SHT 3528-2014 Specification for the construction and acceptance of petrochemical steel storage tank subgrade & foundation
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ICS 93.020 P 72 Record No.: J2000-2015 Petrochemical Industry Standard of the People's Republic of China SH/T 3528-2014 Substitute SH/T 3528-2005 _______________________________________________________________________________ Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry Issued on July 9, 2014 Implemented on November 1, 2014 Issued by Ministry of Industry and Information Technology of the People's Republic of China SH/T 3528-2014 Contents Foreword............................................................................................................................................. 3 1. Scope............................................................................................................................................... 5 2. Normative References.....................................................................................................................5 3. Terms and Definitions.....................................................................................................................6 4. General Provision............................................................................................................................8 4.1 Basic provisions............................................................................................................................ 8 4.2 Type of storage tank foundations..................................................................................................9 5. Subgrade Construction.................................................................................................................. 11 5.1 Basic provisions.......................................................................................................................... 11 5.2 Subgrade acceptance................................................................................................................... 12 6. Storage Tank Foundation Construction........................................................................................ 13 6.1 Excavation and backfilling..........................................................................................................13 6.2 Foundation cushion..................................................................................................................... 17 6.3 Reinforced concrete foundation.................................................................................................. 18 6.4 Packing layer and impervious layer / sand layer in ring wall.....................................................23 6.5 Asphalt sand insulating layer...................................................................................................... 29 6.6 Heat insulation layer................................................................................................................... 32 6.7 Construction of auxiliary facilities..............................................................................................33 7. Leak Test and Foundation Settlement Observation......................................................................33 7.1 Basic provisions.......................................................................................................................... 33 7.2 Settlement observation results.................................................................................................... 36 8. Defect Disposal............................................................................................................................. 36 9. Technical Documents for Hand over............................................................................................ 37 Annex A (Normative) Classification of Section / Subsection Project, Item Project.....................39 Annex B (Informative) Cylinder Diesel Piling Hammer Parameter............................................. 40 Annex C (Normative) Quality Control Criteria for Packing Layer and Asphalt Sand Insulating Layer..................................................................................................................................................41 1 SH/T 3528-2014 Annex D (Informative) Trademark and Performance of Asphalt..................................................42 Bibliography......................................................................................................................................43 Explanation of Wording in This Specification................................................................................. 44 Add: Explanation of Provisions........................................................................................................ 45 2 SH/T 3528-2014 Foreword After extensive investigation and research, the drafting group of standard carefully summarized practical experience, referred to relevant international standards and foreign advanced standards, and revised this Specification on the basis of extensive opinions according to the requirements of Preparation and Revision Plan of the Second Batch of Industry Standards in 2012 (GXTK [2012] No. 119) of the Ministry of Industry and Information Technology of the People's Republic of China. This Specification is divided into 9 chapters and 4 Annexes. The main technical contents of this Specification include: ground improvement technologies; reinforced concrete foundation construction quality acceptance items, standards and procedures; construction site quality management and quality control requirements; quality defect disposal technologies. This Specification is revised on the basis of SH/T 3528-2005 Specification for the Construction and Acceptance of Petrochemical Steel Storage Tank Subgrade & Foundation. The main technical contents of the revision are: — Expanding the application scope of this Specification; — Adding the terms; — Adding technical regulations on heat insulation of storage tank foundation; — Adding technical regulations on seepage control of storage tank foundation; — Adding relevant requirements for mass concrete construction; — Adding relevant requirements for the construction quality defect disposal; — Defining the classification of subsection project; defining the quality inspection items, sampling inspection quantity and inspection methods of item project; — Adding 2 normative annexes (quality control criteria for packing layer and asphalt sand insulating layer, and classification of section / subsection project, item project), and 1 informative annex (trademark and performance of asphalt); — Modifying the cylinder diesel piling hammer parameter (original Annex D); — Deleting 7 original informative annexes, including Annex A (Common Construction Equipment for Dynamic Compaction, Vibroflotation Pile and Sand Pile Foundation), Annex B 3 SH/T 3528-2014 (Provisions on Dynamic Compaction Test), Annex C (Particle Grading Range of Gravel or Stone), Annex E (Mix Proportion and Main Physical Properties of Sulfur Mastic), Annex F (Application Scope and Performance of Drilling / Punching Equipment), Annex G (Pile Formation Technology), Annex H (Trenching and Deviation Correction Method for Storage Tank Foundation). — Deleting the water filled preloading foundation. This Specification is managed by Sinopec Group, daily managed by Sinopec Group Guangzhou Construction Technology Branch, and interpreted by Tianjin Zhongye Petroleum and Chemical Construction Engineering Co., Ltd. In case of any comments and suggestions during the implementation, please send them to the daily management organization and chief development organization. Daily management organization of this Specification: Sinopec Group Guangzhou Construction Technology Branch Mailing address: No. 81, Zhongshan Seventh Road, Liwan District, Guangzhou City Postcode: 510145 Tel: 020-28348176 Fax: 020-28348169 Chief development organization of this Specification: Tianjin Zhongye Petroleum and Chemical Construction Engineering Co., Ltd. Mailing address: No. 194, Century Avenue, Binhai New Area (Dagang District), Tianjin Postcode: 300270 Participating development organization of this Specification: The Fifth Construction Company of Sinopec Main drafters of this Specification: Wang Shuiping, Li Chengzhi, Jiang Shidong, Guo Jianping Main reviewers of this Specification: Guan Weiqing, Ge Chunyu, Nan Yalin, Wang Yonghong, Tan Lijing, Zheng Hongzhong, Qian Lixia, Haobin, Li Yuhua, Bi Shukai, Li Changkun, Zhao Zhifeng, Yang Xiaowu This Specification was issued and revised in 1993 and 2005 for the first time. This is the second revision. 4 SH/T 3528-2014 Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry 1. Scope This Specification specifies the construction technology and quality criteria of steel storage tank subgrade and foundation, foundation settlement observation, and the requirements for technical documents of project acceptance and handover. This Specification is applicable to the construction and acceptance of the vertical cylindrical steel storage tank subgrade and foundation in petrochemical and coal chemical industries, as well as the construction and acceptance of the steel gas tank subgrade and foundation. It is not applicable to the construction and acceptance of the prestressed concrete steel storage tank subgrade and foundation. 2. Normative References The following documents are vital for the application of this Specification. For dated references, only the dated version is applicable to this Specification. For undated references, the latest version (including all amendments) is applicable to this Specification. GB/T 50430 Code for Quality Management of Engineering Construction Enterprises GB 50484 Code for Technical of Construction Safety in Petrochemical Engineering GB 50496 Code for Construction of Mass Concrete GB/T 50756 Technical Code for Ground Treatment of Steel Tanks GB/T 17639 Geosynthetics-Synthetic Filament Spunbond and Needlepunched Nonwoven Geotextiles GB/T 17643 GB 1499.2 Geosynthetics - Polyethylene Geomembrane Steel for the Reinforcement of Concrete - Part 2: Hot Rolled Ribbed Bars JGJ 18 Specification for Welding and Acceptance of Reinforcing Steel Bars JGJ 46 Technical Code for Safety of Temporary Electrification on Construction Site JGJ/T 104 Specification for Winter Construction of Building Engineering JGJ 107 Specification for Winter Construction of Building Engineering JGJ/T 178 Technical Specification for Application of Shrinkage-compensating Concrete 5 SH/T 3528-2014 SH/T 3503 Regulation of Technical Document for Construction Completion of Petrochemical Industry Project SH/T 3510 Acceptance Specification for Construction Quality of Equipment Concrete Foundation in Petrochemical Engineering 3. Terms and Definitions The following terms and definitions are applicable to this Specification. 3.1 Ground improvement Engineering measures taken to improve the bearing capacity of the foundation or its deformation or permeability. 3.2 Composite foundation Foundation in which part of the soil is strengthened or replaced to form a reinforcement, and the reinforcement and the surrounding foundation soil jointly bear the load. 3.3 Cushion A hard and dense foundation soil obtained by excavating the shallow soft soil layer or uneven soil layer on the surface, backfilling the specified materials, then compacting or tamping. 3.4 Slope protected foundation Foundation that the load is jointly borne by the concrete slope protection or gravel slope protection and the packing layer, sand layer, asphalt sand insulating layer in the slope protection. 3.5 Ring wall foundation Foundation that the load is jointly borne by the reinforced concrete ring wall and the packing layer, sand layer and asphalt sand insulating layer in the ring wall. 3.6 Outside ring wall foundation Foundation that the load is jointly borne by the reinforced concrete ring wall and the packing layer, sand layer and asphalt sand insulating layer in the ring wall. 6 SH/T 3528-2014 3.7 Pile foundation Foundation that the load is jointly borne by the pile, the reinforced concrete pile cap connected to the pile top and the packing layer, sand layer, asphalt sand insulating layer on the cap. 3.8 Asphaltic sands insulating layer Part composed of slope protected foundation, ring wall / outside ring wall foundation and pile foundation structure paved with the mixture of asphalt, sand and other materials in the required proportion. 3.9 Sand layer Part composed of slope protected foundation, ring wall / outside ring wall foundation and pile foundation structure paved with the mixture of medium sand, coarse sand or sand-gravel materials in the required proportion. 3.10 Packing layer Part composed of slope protected foundation and ring wall / outside ring wall foundation structure paved with plain soil, lime soil or graded gravel, sand-gravel. 3.11 Compacting test A test method to obtain the maximum dry density and optimum moisture content by using different compaction work (hammer weight × falling distance × hammer speed) respectively to hammer soil samples with different moisture content, and measure the corresponding dry density. 3.12 Maximum dry density Dry density corresponding to the peak point on the relation curve between dry density and moisture content obtained from compacting test. 3.13 Optimum moisture content Moisture content corresponding to the peak point on the relation curve between dry density 7 SH/T 3528-2014 and moisture content obtained from compacting test. 3.14 Compacting factor Ratio of the dry density of the construction quality control of the cushion or the packing layer to the maximum dry density obtained from the compacting test. 4. General Provision 4.1 Basic provisions 4.1.1 The storage tank subgrade and foundation construction shall comply with the provisions of design documents and GB/T 50756. The construction unit shall have corresponding professional qualifications and establish a quality management system and quality inspection system in accordance with the relevant requirements of GB/T 50430. 4.1.2 The following preparations shall be completed before the storage tank subgrade and foundation construction: a) Carry out design disclosure, joint review of drawings and preparation of construction technical documents; b) Arrange the survey points of construction gauge piles and benchmarks, set obvious signs, and take protective measures; c) Find out the distribution of concealed works; d) Build construction roads and drainage facilities. 4.1.3 The quality, inspection items, batch and inspection methods of raw materials such as sand, gravel, cement, steel, lime, asphalt and heat insulation shall comply with the provisions of corresponding product standards. 4.1.4 The storage tank subgrade and foundation project is classified as section project. According to the actual situation of the project, several subsection projects and item projects can be classified according to Annex A. 4.1.5 During the subsection project construction, the quality control of each construction process shall be carried out according to the construction technical documents. After each construction process is completed, the inspection shall be carried out, and the handover inspection shall be carried out for relevant processes among professional types of work, and records shall be made. The construction of the next process can be carried out only after it is qualified. The next process 8 SH/T 3528-2014 of the concealed works shall not be constructed without the inspection and approval of the supervising engineer or the professional technical director of the development unit. 4.1.6 The winter construction of storage tank subgrade and foundation shall comply with the provisions of JGJ/T 104. 4.1.7 The safety technology and labor protection of storage tank subgrade and foundation construction shall comply with the provisions of GB 50484. 4.1.8 The installation and removal of power supply and circuit on the construction site shall comply with the provisions of JGJ 46. 4.1.9 The layout of temporary construction, temporary facilities, temporary fire-fighting facilities, temporary evacuation exits and temporary fire rescue sites on the construction site shall be specified in the construction technical documents, and the general layout shall be drawn. 4.2 Type of storage tank foundations 4.2.1 The type of storage tank foundations can be divided into plain soil slope protected foundation (Figure 4.2.1-1), gravel ring wall slope protected foundation (Figure 4.2.1-2), ring wall foundation (Figure 4.2.1-3), outside ring wall foundation (Figure 4.2.1-4) and pile foundation (Figure 4.2.1-5). 4.2.2 When there are impervious requirements for the storage tank foundation, the impervious layer shall be set. The impervious material should be geotechnical material first, and the impervious layer shall be set between the sand layer and the packing layer. Inner wall of steel storage tank Sealing Steel storage tank Slope protection (construction after leak test) i (center to all sides) Set drain pipes i≥5% Ring beam Ground design Bottom plate of steel storage tank Asphalt sand insulating layer Sand layer Packing layer Figure 4.2.1-1 Plain Soil Slope Protected Foundation 9 SH/T 3528-2014 Inner wall of steel storage tank Steel storage tank Sealing i (center to all sides) Slope protection (construction after leak test) Graded gravel Set drain pipes i≥5% Ring beam Design ground Bottom plate of steel storage tank Asphalt sand insulating layer Sand layer Packing layer Figure 4.2.1-2 Gravel Ring Wall Slope Protected Foundation Inner wall of steel storage tank Steel storage tank Inverted filter Sealing i (center to all sides) Leak aperture Bottom plate of steel storage Design floor tank Asphalt sand insulating layer Sand layer Packing layer Ring wall (reinforced concrete) Foundation cushion Figure 4.2.1-3 Ring Wall Foundation 10 SH/T 3528-2014 Inner wall of steel storage tank Inverted filter Steel storage tank Sealing i (center to all sides) Slope protection (construction after leak test) Leak aperture Ring beam Bottom plate of steel storage tank Design floor Asphalt sand insulating layer Sand layer Ring wall (reinforced concrete) Packing layer Foundation cushion Figure 4.2.1-4 Outside Ring Wall Foundation Inner wall of steel storage tank Inverted filter Steel storage tank Bottom plate of steel storage tank Sealing i (center to all sides) Asphalt sand insulating layer Leak aperture Sand layer Packing layer Design floor Reinforced concrete pile cap Ring wall (reinforced concrete) Foundation cushion Figure 4.2.1-5 Pile Foundation 5. Subgrade Construction 5.1 Basic provisions 5.1.1 Before foundation construction, it is necessary to be familiar with geological survey data and master the environmental conditions of the construction site, including adjacent buildings and structures, underground concealed works in the construction area. 11 SH/T 3528-2014 5.1.2 The performance and applicability of the selected equipment shall be checked and accepted before foundation construction. Refer to Annex B for cylinder diesel piling hammer model and performance. 5.1.3 The foundation construction area shall be flat and meet the requirements of construction equipment for foundation bearing capacity. 5.1.4 The maximum dry density, optimum moisture content and compaction times of each layer of packing such as plain soil foundation, lime soil foundation and sand-gravel foundation shall be determined through compacting test. 5.1.5 Before foundation construction, physical and mechanical property test, static cone penetration test and vane shear test of the soil shall be carried out respectively. 5.1.6 The layer thickness during the construction of plain soil foundation, lime soil foundation, sand-gravel foundation, dynamic compaction foundation, stone chip foundation and graded gravel foundation shall comply with the provisions of Articles 6.4.2~6.4.5 of this Specification. The construction quality shall be controlled by layers in terms of compacting factor and layer thickness, and shall be checked according to Article 5.2.1 of this Specification. 5.2 Subgrade acceptance 5.2.1 The compacting factor and thickness shall be checked for the construction quality acceptance of plain soil foundation, lime soil foundation, sand-gravel foundation, dynamic compaction foundation, stone chip foundation and graded gravel foundation. After the compaction of packing, the cutting-ring method, sand cone method and irrigation method should be used for sampling. The sampling shall be conducted at the depth of 2/3. The penetration measurement method, nuclear instrument method or K30 method can also be used for inspection. For the inspection quantity, if the packing area is less than 1,000m2, the number of points shall not be less than 3; if the area is greater than or equal to 1,000m2 but less than 5,000m2, there shall be one point per 300m2, and if the balance is less than 300m2, it shall be calculated as 300m2; if the area is more than 5,000m2, there shall be one point every 500m2, and if the balance is less than 500m2, it shall be calculated as 500m2. The compacting factor and thickness shall be inspected and accepted according to the layer thickness in Article 5.1.6 of this Specification, and the cumulative error of layer thickness shall not exceed the allowable deviation of total thickness. If there is no provision in the design document, it shall comply with the provisions of Annex C. 12 SH/T 3528-2014 5.2.2 The bearing capacity of cement soil mixing pile composite foundation, sand pile composite foundation, vibroflotation pile composite foundation, soil and lime soil compaction pile composite foundation and cement fly-ash gravel pile composite foundation shall be inspected, and the inspection quantity shall be 0.5%~1% of the number of piles, and shall not be less than 3. 5.2.3 The bearing capacity of reinforced concrete pile composite foundation shall be inspected, and the inspection quantity shall be 0.5%~1% of the total number of piles, and shall not be less than 3. When single pile strength inspection is conducted for reinforced concrete pile composite foundation, the inspection quantity shall be 0.5%~1% of the total number of piles, and shall not be less than 3. 5.2.4 The construction quality acceptance of the cushion foundation, composite foundation and reinforced concrete pile composite foundation shall comply with the provisions of Article 4.1.1 of this Specification. See Table 5.2.4-1~5.2.4-7 for the inspection items and quality criteria of foundation acceptance. 6. Storage Tank Foundation Construction 6.1 Excavation and backfilling 6.1.1 Before the excavation, it is necessary to measure, set out and position first, and then the excavation can be conducted according to the approved construction technical documents after re-measurement and confirmation. Table 5.2.4-1 Inspection Items and Quality Criteria of Plain Soil, Lime Soil and Sand-gravel Foundation Item S/N 1 Dominant item 2 3 1 Plain soil foundation Foundation bearing capacity Compacting factor Moisture content 2 Allowable deviation Unit Value Requirements of design documents Requirements of design documents Requirements of design documents Inspection methods Provisions of design documents See Article 5.2.1 Mass ratio Ratio of drying method calculation to optimum moisture content Moisture content Moisture content - - See Table 6.1.7 Level gauge - Layer thickness - See Table 6.4.3.4 Level gauge - - Layer thickness See Table 6.4.3.4 Level gauge Layer thickness General item Inspection items Lime soil Sand-gravel foundation foundation Foundation Foundation bearing bearing capacity capacity Compacting Compacting factor factor Mix Mix proportion proportion 13 % ±2 SH/T 3528-2014 Table 5.2.4-2 Inspection Items and Quality Criteria of Dynamic Compaction, Stone Chip and Graded Gravel Foundation Allowable deviation Inspection items Item Dominant item General item S/N Dynamic compaction foundation Stone chip foundation 1 Foundation bearing capacity 2 - Foundation bearing capacity Compacting factor Graded sand-gravel foundation Foundation bearing capacity Compacting factor 3 - Mix proportion Mix proportion 1 Center displacement of compacting point - - Top elevation - Layer thickness - Layer thickness 4 - Silt content Silt content % ≤7 5 6 - Particle size Organic content - mm % ≤10 ≤5 2 3 Table 5.2.4-3 Unit Value Requirements of design documents Requirements of design documents Requirements of design documents mm ≤150 mm ±20 mm ±50 See Table 6.4.4.2 Inspection methods Provisions of design documents See Article 5.2.1 Mass ratio Measured with theodolite and steel ruler Level gauge Level gauge Level gauge Water washing method Sieving method Roasting method Inspection Items and Quality Criteria of Sand Pile and Vibroflotation Pile Foundation Item Dominant item S/N Inspection items Allowable deviation Inspection methods Sand pile foundation Vibroflotation pile foundation 1 Foundation bearing capacity Foundation bearing capacity 2 Pumped sand amount - 3 - Packing particles 1 Displacement of pile center Displacement of pile center mm ≤50 - mm +100 -50 - mm -20 mm +50 -20 Measured with steel ruler mm +100 -50 mm ±200 mm ±100 Immersed tunneling method mm ±100 Ballistic method mm ±200 % 1.5H Measured with steel ruler Measured with counter weight and steel ruler Measured with counter weight and steel ruler Measured with counter weight and steel ruler Measured with counter weight and steel ruler Measured with theodolite and steel ruler Hammering method Vibration method Pile diameter 2 - General item Hammering method Hole-forming depth - 4 Perpendicularity 95 Requirements of design documents - Vibration method 3 Value Requirements of design documents % Immersed tunneling method Ballistic method Pile diameter Unit Hole-forming depth Perpendicularity Note: H is hole-forming depth of sand pile and vibroflotation pile (mm). 14 Provisions of design documents Volume ratio of actual and calculated sand amount Sampling inspection Measured with theodolite and steel ruler Measured with steel ruler Measured with steel ruler SH/T 3528-2014 Table 5.2.4-4 Inspection Items and Quality Criteria of Cement Soil Mixing Pile Composite Foundation Item Allowable deviation Unit Value Requirements of design documents Requirements of design documents Requirements of design documents S/N Inspection items 1 Foundation bearing capacity 2 Pile strength 3 Quality of cement and admixture 1 Pile bottom elevation mm 2 Pile top elevation mm 3 4 Pile position deviation Pile diameter mm mm +100 -50 < 50 < 0.04D 5 Perpendicularity % ≤1.5H Dominant item General item ±200 Note: D is pile diameter, and H is pile length (mm). Table 5.2.4-5 Inspection methods Provisions of design documents Regulated methods Quality certificates Measurement of machine head depth Level gauge Measured with steel ruler Measured with steel ruler Measured with theodolite and steel ruler Inspection Items and Quality Criteria of Soil and Lime Soil Compaction Pile Composite Foundation Item S/N 1 Dominant item General item 2 Inspection items Foundation bearing capacity Pile and dry density of soil between piles Allowable deviation Unit Value Requirements of design documents Requirements of design documents Requirements of design documents mm -20 Inspection methods Provisions of design documents See Article 5.2.1 3 Mix proportion 1 Pile diameter 2 Pile length mm +500 3 Pile position deviation mm ≤0.40D 4 Perpendicularity % 1.5H mm ≤5 Measured with steel ruler Measurement of pile pipe length or hole depth Measured with steel ruler Measured with theodolite and steel ruler Sieving method % ≤5 Roasting method 5 Lime particle size Organic content in soil 6 material Note: D is pile diameter, and H is pile length (mm). Table 5.2.4-6 Mass ratio, sampling inspection Inspection Items and Quality Criteria of Cement Fly-ash Gravel Pile Composite Foundation Item Dominant item General item S/N Inspection items 1 Foundation bearing capacity 2 Pile body strength 3 Raw materials 1 2 3 Pile diameter Pile length Pile position deviation 4 Perpendicularity Allowable deviation Unit Value Requirements of design documents Requirements of design documents Requirements of design documents mm -20 mm +100 mm ≤0.40D % Note: D is pile diameter, and H is pile length (mm). 15 ≤1.5H Inspection methods Provisions of design documents Regulated methods Quality certificates Measured with steel ruler Measured with steel ruler Measured with steel ruler Measured with theodolite and steel ruler SH/T 3528-2014 Table 5.2.4-7 Inspection Items and Quality Criteria of Reinforced Concrete Pile Foundation Item Dominant item S/N Inspection items 1 Foundation bearing capacity 2 Precast quality of piles 3 Pile body concrete strength 4 Pile body completeness 1 General item Pile position deviation The number of piles is less than or equal to 16 piles in the pile foundation The number of piles is greater than that of the outermost pile in the 16-pile foundation The number of piles is greater than that of the center pile in the 16-pile foundation 2 Perpendicularity 3 Pile top elevation 4 Pile deviation Allowable deviation Unit Value Requirements of design documents Requirements of design documents Requirements of design documents Requirements of design documents Inspection methods Provisions of design documents Product quality certificates Product quality certificates Provisions of design documents mm 1/2D1 Measured with steel ruler mm 1/3D1 Measured with steel ruler mm 1/2D1 Measured with steel ruler % 0.5H Measured with theodolite and steel ruler Requirements of design documents Center line mm ≤10 Curve vector height at nodal point % 0.1H Note: D1 is pile diameter or side length, and H is pile length (mm). Level gauge Measured with steel ruler Measured with theodolite and steel ruler 6.1.2 Mechanical construction should be adopted for the excavation, and manual leveling shall be carried out during the excavation, or 100mm~300mm thick soil shall be reserved above the base elevation, and manual excavation shall be carried out to the design elevation when the cushion is paved. 6.1.3 Excavation should be carried out continuously. In case of high groundwater level or in the rainy season, dewatering measures shall be taken, and drainage ditches shall be set around the foundation trench (pit). Table 6.1.4 Quality Criteria for Excavation Works Allowable deviation Item Dominant item General item Unit Elevation Displacement of center line Length, width or diameter Properties of base soil Surface flatness Value 0 -50 mm mm 20 +200 -50 Requirements of design documents mm 20 mm 16 Inspection methods Level gauge Measured with theodolite and steel ruler Measured with theodolite and steel ruler Observation or soil sample analysis Level gauge SH/T 3528-2014 6.1.4 After excavation, the trench shall be inspected in time. The foundation trench quality criteria shall comply with the provisions of Table 6.1.4. After trench inspection, cushion construction shall be carried out in time. 6.1.5 The excavation of pile foundation shall be carried out after the pile foundation construction is completed and the quality is qualified, and corresponding protection measures shall be taken for the pile foundation. 6.1.6 Before backfilling, the sundries at the base shall be removed, and the ponding shall be removed. The drainage measures shall be taken during backfilling. 6.1.7 When there are no requirements in the design documents, the laying thickness and compaction times of each layer of backfilling soil shall comply with the provisions of Table 6.1.7. Table 6.1.7 Laying Thickness and Compaction Times of each Layer of Backfilling Soil Layer thickness Compaction times Exciting force mm Times t Smooth wheel roller 250 ~ 300 6~8 ≥5 Vibratory compactor 300 ~ 400 3~4 ≥6 Light-weight rammer 200 ~ 250 3~4 ≥1 Ramming manually ≤200 3~4 ≥ 0.05 Compaction equipment 6.1.8 Sludge, peat, cultivated soil, expansive soil, frozen soil and soil materials with organic impurity content of more than 5% shall not be used for backfilling. The backfilling soil should have the optimum moisture content. If the gravel is used as backfilling soil, the gravel particle size should not be greater than 50mm. 6.1.9 The backfilling shall be compacted in layers and the compacting factor shall be checked by sampling. There shall be 1 point per 400m2 or 30m along the circumference, and each layer shall not be less than 3 points. When there are no requirements in the design documents, the compacting factor shall not be less than 0.90. The inspection methods shall comply with Article 5.2.1 of this Specification. 6.2 Foundation cushion 6.2.1 The construction of concrete cushion shall comply with the following provisions: a) The ready-mixed concrete shall be used; b) The concrete shall be leveled after being vibrated and compacted, and the curing measures shall be taken. 6.2.2 The construction of asphalt sand or asphalt concrete cushion shall comply with the following provisions: 17 SH/T 3528-2014 a) After paving, the cushion shall be leveled and compacted immediately, and the virtual paving thickness of the first layer shall not be less than 60mm; b) The plate vibrator or roller and hot roller shall be used for compaction; c) The temperature before compaction is 150°C~160°C, and the temperature after compaction is not lower than 110°C. When the construction ambient temperature is lower than 5°C, the temperature before compaction takes the highest value; d) During layered construction, the distance between the vertical construction joints of the upper and lower layers shall not be less than 500mm, and the horizontal construction joints shall be coated with a layer of hot asphalt. 6.2.3 The elevation and thickness of cushion construction shall be controlled, and the allowable deviation of elevation is ±8mm; the allowable thickness deviation is ±10% of the design thickness. 6.2.4 When the cushion concrete has strength requirements, the sample blocks for standard maintenance shall be reserved for the cushion concrete according to the provisions of SH/T 3510. 6.3 Reinforced concrete foundation 6.3.1 Steel bar construction 6.3.1.1 Steel bar for storage tank foundation shall have quality certificates meeting the requirements of GB 1499.2, and shall be rechecked by batch. 6.3.1.2 The steel bars shall be temporarily fixed and erected during installation, and the arrangement distance of auxiliary components shall be determined in the construction technical documents; The temporary components for fixing and erecting the steel bars shall be removed one by one with the installation of formwork. 6.3.1.3 After the steel bars are installed, the construction of the next process can be carried out only after the self-inspection is qualified and the concealed works are inspected and accepted. The steel bar installation quality criteria shall comply with the provisions in Table 6.3.1.3. 6.3.2 Formwork construction 6.3.2.1 The set-shaped steel formwork or wood glued formwork should be used for pile cap (bottom plate) formwork. The contact surface between formwork and concrete shall be clean, flat and smooth, and formwork isolation agent shall be painted; the stability, strength and stiffness of the formwork support system shall be specified in the construction technical documents. 6.3.2.2 The positioning sideline, circumferential axis and embedded bolt position of ring wall, pile cap (bottom plate) shall be marked on the concrete cushion. 18 SH/T 3528-2014 Table 6.3.1.3 Steel Bar Installation Quality Criteria Unit: mm Item Allowable deviation Connection mode of hoop or Requirements of design vertical stressed load-bearing documents Inspection methods Observation bars Dominant item Mechanical properties of steel Provisions in JGJ 107 and JGJ bar joints 18 Checking qualification certificate of connectors, and mechanical performance test report of joints Type, grade and specification of Requirements of design load-bearing bars documents Spacing of main load-bearing Observation, measured with steel ruler ±10 Measured with steel ruler ±5 Measured with steel ruler ±20 Measured with steel ruler ±10 Measured with steel ruler ±8 Measured with steel ruler bar Row spacing of main General load-bearing bar item Stirrup spacing Protective layer Pile cap / of main bottom plate load-bearing bar Ring wall 6.3.2.3 The formwork removal time of the concrete ring wall shall not be less than 3d, and the formwork removal time for winter construction shall comply with relevant provisions of JGJ/T 104. 6.3.2.4 Split bolts for foundation formwork reinforcement shall be cut off or removed before backfilling, and shall comply with the following provisions: a) Anti-corrosion treatment shall be carried out after the embedded and fixed split bolts are cut off; b) After the withdrawable split bolts are removed, the installation holes shall be completely filled with 1:2 cement mortar, and the surface shall be troweled and calendered. Table 6.3.2.5 Allowable Installation Deviation of Storage Tank Foundation Formwork Unit: mm Allowable Item deviation Dominant Deviation of center point position from item the foundation center Radial section of ring wall 0 ~ +10 Measured with steel ruler General Radius of ring wall formwork 0 ~ +5 Measured with steel ruler 10 Measured with theodolite, level gauge item Leak aperture 10 Inspection methods Measured with total-station instrument, theodolite and steel ruler Position and steel ruler Slope ≥ 5% 19 Measured with level ruler SH/T 3528-2014 6.3.2.5 The allowable installation deviation of formwork shall comply with the provisions of Table 6.3.2.5. 6.3.3 Foundation bolt 6.3.3.1 The oil stain, rust and oxide scale on the bolt surface shall be removed before installation. 6.3.3.2 Wood and steel fixed-distance formwork should be used for bolt installation, or other measures can be taken to fix the bolt position. 6.3.3.3 Concealed acceptance shall be carried out after the self-inspection of the bolt installation is qualified. 6.3.3.4 During concrete pouring and after the removal of bolt spacing formwork, the exposed part of the bolt shall be protected. 6.3.3.5 After the completion of concrete pouring and before the final setting of concrete, the bolt position should be calibrated again. 6.3.3.6 The bolt installation quality criteria shall comply with the provisions in Table 6.3.3.6. Table 6.3.3.6 Allowable Deviation of Bolt Installation Position Unit: mm Item Dominant item Bolt specification, model, material Allowable deviation Inspection methods Requirements of design Checking product qualification documents certificate Deviation of center line position 10 from the foundation center line General item Measured with theodolite and steel ruler Measured with level gauge or Bolt top elevation 0 ~ +10 Exposed length 0 ~ +20 Measured with steel ruler Radius of embedded bolts ±15 Measured with steel ruler Chord length of adjacent bolts ±15 Measured with steel ruler stay wire and steel ruler 6.3.4 Concrete construction 6.3.4.1 Ready-mixed concrete should be used for storage tank foundation concrete, which shall comply with relevant provisions of GB 14902; independent sample block shall be reserved for each storage tank foundation; the fabrication of concrete sample block and concrete curing shall comply with the relevant provisions of SH/T 3510, and the construction of mass concrete shall also comply with the relevant provisions of Article 6.3.5 of this Specification. 6.3.4.2 The ring wall and the bottom plate (pile cap) can be poured separately from the construction joint, which shall be left on the top surface of the bottom plate (pile cap); before secondary pouring, the construction joint shall be cleaned and wetted after roughening. 20 SH/T 3528-2014 6.3.4.3 The ring wall concrete shall be poured and formed at one time, and the concrete on the upper surface shall be calendered at one time without secondary plastering; when there is a leveling layer on the top, the surface shall be roughened. The non-shrinkage grouting material with a grade higher than the concrete strength of the ring wall shall be used, and the thickness should not be less than 30mm. After construction, the top surface flatness shall not exceed 7mm on any 10m arc length of the surface, and the height difference of any two points on the whole circumference shall not exceed 13mm. 6.3.4.4 After the formwork is removed, the allowable deviation of storage tank foundation position and overall dimension shall comply with the provisions of Table 6.3.4.4. Table 6.3.4.4 Deviation of Overall Dimension of Cast-in-situ Concrete Storage Tank Foundation Unit: mm Allowable Item Dominant item item Measured with theodolite and Center position 15 Radial section of ring wall 0 ~ +15 Measured with steel ruler Inner diameter 0 ~ -10 Measured with steel ruler Outer diameter 0 ~ +10 Measured with steel ruler Radius of annular embedded bolt -5 ~ +10 Measured with steel ruler Chord length of adjacent bolts ±3 Measured with steel ruler Leak aperture position 20 Radius of ring wall General Inspection methods deviation Every 10,000mm Flatness of top arc length surface of ring wall Any two points of arc length 7 13 steel ruler Measured with theodolite, level gauge and steel ruler Measured with level gauge and steel ruler Measured with level gauge and steel ruler 6.3.4.5 For the construction of reinforced concrete pile cap or ring wall, if there are no requirements in the design documents and the circumference (center circle) length of reinforced concrete ring wall is greater than 40m, the post-cast strip should be reserved for segmental pouring, and the pouring shall be carried out according to the following provisions: a) The post-cast strip of pile cap or ring wall shall be poured with micro-expansive concrete with a higher strength grade after 28d of concrete pouring of pile cap or ring wall, and shall comply with the provisions of JGJ/T 178. b) The post-cast strip joints of pile cap or ring wall shall avoid the steel bar connection area and be set according to the following Figure 6.3.4.5. 21 SH/T 3528-2014 1—Formwork; 2—Vertical bar / bottom plate steel bar; 3—Post-cast strip; 4—Concrete ring wall (pile cap) Figure 6.3.4.5 Schematic Diagram of Reserved Post-cast Strip 6.3.4.6 The leak apertures on the ring wall shall be evenly arranged every 10m~15m along the circumference of the storage tank, with a slope of no less than 5%, from inside to outside. Pebbles or gravels with a particle size of no less than 30mm shall be used for water filtration at the water inlet. 6.3.4.7 The underground part of the storage tank foundation shall be backfilled in time after the formwork is removed, and the aboveground part shall be protected. 6.3.5 Mass concrete construction 6.3.5.1 When the concrete construction of storage tank foundation meets the requirements for mass concrete, the provisions of GB 50496 shall be implemented. 6.3.5.2 Before mass concrete construction, adiabatic heating and thickness of heat insulation layer shall be calculated, and provisions shall be specified in the construction technical documents. 6.3.5.3 Special disclosure shall be carried out before mass concrete pouring, and inspection and confirmation shall be carried out according to the following requirements: a) The material reserve meets the requirements of one-time continuous pouring; b) The vibrating and pouring equipment and standby equipment are in good condition, and the performance meets the requirements; c) Curing materials and temperature control materials meet the requirements; d) The transportation road is smooth. e) The supply of water and electricity is normal, and standby water and electricity lines are set. 6.3.5.4 Mass concrete should be poured continuously in layers, with the layer thickness of 300mm~500mm, and the surface bleeding shall be removed in time. 6.3.5.5 The pouring and molding temperature of mass concrete should be controlled at 5°C~30°C. 6.3.5.6 The temperature monitoring of the mass concrete pouring block should be measured and recorded by the embedded automatic thermometer or contact-type thermometer in embedded pipe. 22 SH/T 3528-2014 6.3.6 Foundation appearance quality inspection 6.3.6.1 After the foundation construction is completed, the supervision unit, the development unit and the construction unit shall jointly inspect the appearance quality according to Table 6.3.6.1 and determine the nature of the defects. Table 6.3.6.1 Name Crack Phenomenon Foundation Appearance Quality Defects Serious defects Vertical crack of Through crack with width reinforced concrete greater than 0.3mm and length ring wall greater than 1/2 of the height of Common defects Other cracks the ring wall Exposed Exposed structural Exposed structural load-bearing Exposure of other steel bars reinforcing load-bearing bar bar Joint Concrete defects at The joint has defects affecting The joint has defects that do not affect defect construction joints the force transmission force transmission performance of the and post-cast strips; performance of the structure, structure Embedded part and the embedded bolts or bar defects embedded steel plates are loose Surface Pitted surface, Pitted surface, peeling, sanding, Pitted surface, peeling, sanding, defect peeling, sanding, contamination, slag inclusion, contamination, slag inclusion, cavity or contamination, slag cavity or looseness affecting the looseness not affecting the durability of inclusion, cavity, durability of structure structure, and uncleaned or untreated looseness, etc. materials for construction measures 6.3.6.2 For cracks, the defect nature shall be checked and confirmed again after the leak test of the storage tank. 6.3.7 Physical inspection of foundation structure 6.3.7.1 When it is necessary to conduct physical inspection on the storage tank foundation structure, the inspection parts and inspection quantity shall be jointly selected by the supervision unit and the construction unit. 6.3.7.2 The physical inspection of foundation structure shall be organized and implemented by the project technical director of the construction unit under the witness of the supervising engineer. 6.3.7.3 The inspection and test unit undertaking the physical inspection of structure shall have corresponding qualifications. 6.4 Packing layer and impervious layer / sand layer in ring wall 6.4.1 General requirements 6.4.1.1 The materials of packing layer and impervious layer / sand layer shall be inspected and accepted according to Article 4.1.3 of this Specification after mobilization. 23 SH/T 3528-2014 6.4.1.2 Sludge, cultivated soil, expansive soil, frozen soil and soil materials with organic impurity content greater than 5% shall not be used as plain soil packing. 6.4.1.3 The sand layer material should be medium and coarse sand with good particle grading and hard texture. The silt content shall not exceed 5%, and there shall be no grass roots, garbage and other impurities. 6.4.1.4 The maximum dry density, optimum moisture content and compaction times of each layer of plain soil, lime soil, sand-gravel shall be determined through compacting test. The moisture content of the packing used should be the optimum moisture content. 6.4.1.5 The construction of the packing layer in the ring wall can be carried out only when the concrete strength of the ring wall reaches more than 75% of the design strength. The ring wall concrete strength should be determined by the compressive strength of sample blocks under the same conditions or the strength detected by rebound apparatus. 6.4.1.6 During the construction of the packing layer in the ring wall, the drainage of the backfilling area shall be well done. Rainproof measures shall be taken for the construction in rainy days, and the construction shall not be carried out in rainy days. 6.4.1.7 According to the selected compaction equipment, the laying thickness and compaction times of each layer of packing shall be controlled according to the provisions of Articles 6.4.2~6.4.5 of this Specification. After the compaction, the dry density shall be measured by sampling according to the provisions of Article 5.2.1 of this Specification. At the edges and corners of manual compaction, there shall be no less than 1 inspection point every 20m or every 3 places. 6.4.1.8 When backfilling on the natural floor, the sundries and ponding on the surface of the natural floor shall be cleaned, and the cleaning and leveling of the natural floor shall be accepted before the construction of the packing layer. 6.4.1.9 During the construction of packing layer, attention shall be paid to the protection of leak apertures, and the inverted filter of leak apertures shall be constructed in time. 6.4.1.10 During the construction of the packing layer, its bottom surface should be laid on the same elevation. If the depth is different, the bottom surface of the foundation trench shall be excavated into steps or slope lapped joint, and the lapped joint shall be compacted. The construction shall be carried out in the order of deep first and then shallow. During the construction in layers and sections, the staggered distance between the joints of the upper and 24 SH/T 3528-2014 lower layers of lime soil shall not be less than 500mm. 6.4.2 Plain soil packing layer 6.4.2.1 The plain soil plain soil shall comply with the requirements of Article 6.4.1.2 of this Specification, shall have the optimum moisture content, and shall not contain bricks and tiles. The maximum particle size shall not be greater than 50mm; in case of gravel, the gravel particle size shall not be greater than 50mm. The optimum moisture content and maximum dry density of various plain soils are shown in Table 6.4.2.1. Table 6.4.2.1 Optimum Moisture Content and Maximum Dry Density of Plain Soil Types of soil Optimum moisture content (mass ratio), % Maximum dry density, g/cm3 Sandy soil 8 ~ 12 1.80 ~ 1.88 Silt 16 ~ 22 1.61 ~ 1.80 Silty clay 18 ~ 21 1.65 ~ 1.74 Clay 19 ~ 23 1.58 ~ 1.70 6.4.2.2 The layered paving thickness of plain soil shall comply with the provisions of Article 6.1.7 of this Specification. The parts within 500mm close to the ring wall that are not suitable for mechanical compaction shall be compacted manually. 6.4.3 Lime soil packing layer 6.4.3.1 When there are no requirements for mix proportion of the lime soil in the design documents, the volume mix proportion of lime and soil should be 2:8 or 3:7; the soil materials should be silty clay, shall not contain soft impurities, and shall be screened. Its particle size shall not be greater than 15mm. 6.4.3.2 The lime shall be the cured lime powder, and the particle size shall not be greater than 5mm. There shall be no uncured quicklime block. 6.4.3.3 During the construction of lime soil packing layer, the moisture content shall be controlled at ±2% of the optimum moisture content according to the nature of soil materials. Damp lime soil shall be used after re-drying. 6.4.3.4 The lime soil shall be mixed evenly with the same color and paved in layers. The laying thickness is shown in Table 6.4.3.4. The thickness of each layer shall be controlled by marking piles set on the side wall of the foundation pit. 6.4.3.5 The lime soil shall be compacted or tamped along with the paving, and cannot be compacted or tamped every other day. The compaction method should be mechanical compaction supplemented by manual compaction. The compacted and tamped lime soil cannot be soaked in 25 SH/T 3528-2014 water within 7d. Table 6.4.3.4 Layer Laying Thickness of Each Layer of Lime Soil Type of ramming Equipment Thickness equipment mass (t) mm Road roller 6 ~ 10 200 ~ 300 Dual wheel 0.12 ~ 0.3 200 ~ 250 Frog hammer, diesel hammer 0.04 ~ 0.08 ≤200 Light-weight ramming equipment Stone rammer, wooden rammer Remark Manual ramming, drop distance of 400mm~500mm, compacted half ramming 6.4.3.6 After lime soil compaction and tamping, the surface shall be flat without looseness, peeling and cracks. 6.4.4 Graded gravel packing layer 6.4.4.1 The graded gravel shall be hard, dense and unweathered engineering stone, and shall meet the following requirements: a) The particle size should be 5mm~40mm; b) The water absorption should not more than 5%; c) The silt content should not be greater than 5%. 6.4.4.2 The graded gravel should not be paved directly from the bottom of foundation pit. A 150mm~300mm sand layer shall be paved first or a 200mm thick lime soil or clay impervious layer shall be made. The laying thickness of each layer shall be determined according to the roller properties, but shall not be greater than 500mm, and the thickness deviation of each layer shall be ±50mm. 6.4.4.3 For non-continuously graded gravel, the stone chips and gravels of more than two sizes should be used, and the best mix proportion after laboratory screening shall be provided. 6.4.5 Sand-gravel packing layer 6.4.5.1 Naturally graded sand-gravel should be used as the material for sand-gravel packing layer. When manually graded sand-gravel is used, medium sand, coarse sand, gravel sand, gravel (pebble), stone chips or other industrial waste residues with hard texture, stable performance and non-corrosiveness should be selected and mixed evenly. 6.4.5.2 Sand-gravel materials shall not contain grass roots, garbage and other foreign organic matters, and the particle size of gravel or pebble should not be greater than 50mm. 6.4.5.3 The sand-gravel packing layer shall be laid in layers, and the layer thickness can be controlled by marking piles during construction. The laying thickness and optimum moisture 26 SH/T 3528-2014 content of each layer shall comply with the provisions of Table 6.4.5.3. The vibration rolling method should be adopted for layered compaction, or vibration compaction, compaction and other methods can be selected. Table 6.4.5.3 Laying Thickness and Optimum Moisture Content of Each Layer of Sand-gravel Foundation Paving thickness of each layer Optimum moisture content during construction (mm) (%) 200 ~ 250 15 ~ 20 Compaction method 150 ~ 200 8 ~ 12 Rolling method 250 ~ 350 8 ~ 12 Tamping method Flat vibration method 6.4.6 Sand layer 6.4.6.1 Medium and coarse sand (fineness modulus not less than 2.3) or sand-gravel mixture with maximum particle size not more than 20mm should be used for sand layer. There shall be no grass roots, garbage and other foreign organic matters, and the silt content shall not be more than 5%. Silty sand, fine sand (fineness modulus less than 2.3), frozen sand and sea sand without desalination shall not be used. 6.4.6.2 During the construction of the sand layer, water shall be sprayed to keep the moisture content of sand at about 20%. 6.4.6.3 During the construction of the sand layer, the slope required by the design documents shall be formed from the center to the periphery. The surface flatness shall be protected after the completion of the sand layer. 6.4.6.4 During the construction of the sand layer, auxiliary marking piles should be set every 2m as elevation control points to control the elevation of the sand layer. 6.4.6.5 When the asphalt sand insulating layer is directly laid on the sand layer, the surface of the sand layer before construction shall be dry, and not sticky or agglomerated. 6.4.7 Quality acceptance standards 6.4.7.1 After the construction of packing layer and sand layer, the inspection items and quality criteria shall comply with the provisions of Table 6.4.7.1. 6.4.7.2 When there are no requirements in the design documents, the compacting factor of packing layer and sand layer shall comply with the provisions of Annex C. 27 SH/T 3528-2014 Table 6.4.7.1 Construction Quality Criteria of Packing Layer in Ring Wall Unit: mm Item Allowable deviation Inspection methods 0 ~ -50 Level gauge -20 ~ +10 Level gauge Plain soil, lime soil, Dominant graded gravel Elevation Sand, sand-gravel item Compacting factor item See Article 5.2.1 documents Requirements of design Thickness General Requirements of design Level gauge documents Surface flatness Measured with level gauge or stay 20 wire and steel ruler 6.4.8 Impervious layer 6.4.8.1 When the clay is used as the impervious layer, the total thickness after layered compaction shall not be less than 500mm, and the compacting factor of each layer shall not be less than 0.97. 6.4.8.2 When the geomembrane is used as the impervious layer, the thickness of geomembrane shall not be less than 1.5mm, and the geomembrane material shall comply with the provisions of GB/T 17643. 6.4.8.3 When the geotextile is used as the geomembrane protection material, the filament non-woven geotextile shall be used, and the size shall not be less than 600g/m2; the performance index of the geotextile shall comply with the provisions of GB/T 17639. 6.4.8.4 The geomembrane welding shall comply with the following provisions: a) Test welding shall be conducted before welding, and various working conditions and parameters of the welder shall be inspected; b) Oil stain, dust, sediment and other sundries at the joint shall be removed before welding; c) Geomembrane shall be welded by lapping and the lapping method and width shall comply with the provisions of Table 6.4.8.4; Table 6.4.8.4 Lapping Method and Width of Geomembrane Unit: mm Materials Geomembrane Lapping method Lapping width Allowable deviation Sweat soldering 100 ±20 Extrusion welding 75 ±20 d) The weld surface shall be flat without cracks, pores, missing welding or skip welding; e) After welding, measures shall be taken to prevent the geomembrane from being damaged by wind; 28 SH/T 3528-2014 f) In case of any of the following conditions in the welding environment, welding shall not be carried out without protective measures: 1) Wind velocity is more than 2m/s; 2) Relative humidity is more than 60%; 3) Rainy and dew environment; 4) Ambient temperature is lower than 5°C. 6.4.8.5 The geotextile shall be flat, and the flatness should be controlled within ±20mm. The lapping method and width of geotextile shall comply with the provisions in Table 6.4.8.6. Table 6.4.8.6 Lapping Method and Width of Geotextile Unit: mm Materials Non-woven geotextile Lapping method Lapping width Allowable deviation Stitching joint 75 ±15 Hot sticking joint 200 ±25 6.4.8.6 The stitching of geotextile shall use UV resistant and chemical resistant polymer thread, and double-stitched seam shall be used. When non-woven geotextiles are connected through hot sticking, all lapping parts within the lapping width shall be bonded. 6.5 Asphalt sand insulating layer 6.5.1 Commercial hot asphalt sand should be used as asphalt sand, which can also be mixed on site. 6.5.2 During hot mixing of asphalt sand on site, the sand shall be heated to 100°C~150°C and the asphalt shall be heated to 160°C~200°C. It shall be mixed evenly in hot state and meet the following requirements: a) The sand used shall be dry medium and coarse sand, and the silt content in the sand shall not be greater than 5%; b) When the medium temperature in the storage tank is lower than 80°C, No. 60A pavement petroleum asphalt or No. 30 building petroleum asphalt should be used; c) When the medium temperature in the storage tank is greater than 80°C, No. 30 building petroleum asphalt should be used, and the heat insulation layer should be used at the bottom of the storage tank; d) The mix proportion of asphalt sand can be configured according to the volume ratio of 90% medium and coarse sand and 10% asphalt or 92% medium and coarse sand and 8% asphalt; it can also be configured according to the weight ratio of 93% medium and coarse sand and 7% 29 SH/T 3528-2014 asphalt; e) When there is no petroleum asphalt with appropriate grade, it can be configured according to the requirements of Annex D. 6.5.3 Before laying asphalt sand, the sand layer surface shall be dry, and the concrete surface shall be evenly coated with cold primer oil. The asphalt sand shall be laid in layers, and the laying thickness of the first layer shall not be less than 60mm. The same layer can be laid according to the fan-shaped partition block in Figure 6.5.3-1, and the maximum arc length of the fan-shaped segment shall not be greater than 12m. It can also be laid according to the continuous belt partition block in Figure 6.5.3-2, and the continuous belt should be 6m. The joints of upper and lower partition blocks shall be staggered, and the staggered distance shall not be less than 500mm. Figure 6.5.3-1 Schematic Diagram of Fan-shaped Partition Block of Asphalt Sand Insulating Layer Figure 6.5.3-2 Schematic Diagram of Annular Partition Block of Asphalt Sand Insulating Layer 6.5.4 The laying temperature of hot asphalt sand shall not be lower than 140°C and shall be paved smoothly. A non-vibrating roller with a total mass of not more than 50 kN or a roller with an 30 SH/T 3528-2014 exciting force of 10kN~30kN should be used for rolling; For local trimming, the plate vibrator can be used for vibration, or the fire roller can be used for rolling, and then the heated soldering iron can be used for soldering. 6.5.5 After the interruption of hot asphalt sand construction and before paving, the edge of the compacted layer shall be heated and coated with a layer of hot asphalt. The joint shall be rolled and leveled without joint trace. 6.5.6 The compacting factor of the asphalt sand insulating layer shall be checked by sampling method. If there are no requirements in the design documents, the inspection method of compacting factor is shown in Annex C, and the inspection quantity is: a) One place every 200m2~500m2, but not less than 3 places for each storage tank foundation; b) For the single storage tank foundation of 50,000m3 and above, when the unit has the construction method or construction technology summary of the same foundation, each storage tank foundation can be randomly inspected at 6 places; c) One place can be inspected for the foundation of each other storage tank foundation if the capacity of the tank farm is more than 100,000m3; the number of storage tanks is more than 5; the construction process is the same; the first foundation is qualified according to Item a) of this Article. 6.5.7 The actual thickness of the asphalt sand insulating layer after compaction shall not be less than 95% of the design thickness. If there are no requirements in the design documents, the thickness inspection method is shown in C.2, and the inspection quantity shall not be less than 1 for each storage tank. 6.5.8 The surface of the asphalt sand insulating layer shall be flat and dense without cracks. The surface flatness of asphalt sand shall be checked according to the following provisions: a) When the diameter of the storage tank is less than 25m, it can be measured from the center of the foundation to the periphery of the foundation. The surface flatness shall not be greater than 25mm. The number of measuring points shall not be less than 10 per 100m2. Those less than 100m2 shall be calculated as 100m2; b) When the diameter of the storage tank is equal to or greater than 25m, the elevation shall be measured at equal diversion points on each circumference by taking the center of the foundation as the center of the circle and making concentric circles with different radii. The minimum number of measuring points shall comply with the provisions of Table 6.5.8. For the 31 SH/T 3528-2014 measuring points on the same circumference, the difference between the measured elevation and the calculated elevation shall not be greater than 20mm. Table 6.5.8 Concentric Circle Diameter and Number of Inspection Points for Checking the Surface Flatness of Asphalt Sand Insulating Layer Storage tank diamete r (D) D > 80 40<D≤8 0 25<D≤4 0 Concentric circle diameter (d) Number of measuring points Inspectio Circl Circl Circl Circl Circl Circl Circl Circl Circl Circl n eI e II e III e IV eV eI e II e III e IV eV methods D/6 D/3 D/2 2D/3 5D/6 8 16 24 32 40 D/5 2D/5 3D/5 4D/5 - 8 16 24 32 - Level gauge D/4 D/2 3D/4 - - 8 16 24 - - 6.5.9 The asphalt sand insulating layer shall not be constructed in rainy days. 6.5.10 During the construction of the asphalt sand insulating layer, measures shall be taken to protect the sand layer, and the transport vehicle wheel shall not directly roll the sand layer. 6.5.11 The construction quality control standards of the asphalt sand insulating layer shall comply with the provisions in Table 6.5.11. Table 6.5.11 Asphalt Sand Quality Control Standards Acceptable deviation Item S/N or value Inspection items Unit 1 General 2 Requirements of design Quality of asphalt sand documents materials Field mixed Requirements of design asphalt sand documents Commercial Requirements of design Mix asphalt sand documents proportion Field mixed Requirements of design asphalt sand documents 3 Compacting factor 1 Thickness 2 item Value Commercial Dominant item Inspection methods Surface flatness Requirements of design documents mm ±5% Quality certificates Regulated methods Quality certificates Field measurement See Annex C Level gauge and ruler Measured with stay wire D < 25m mm 25 D≥25m mm 20 Level gauge and steel ruler 3 Laying temperature ℃ ≥140 Thermometer 4 Center elevation mm ±20 Level gauge 6.6 Heat insulation layer 6.6.1 When the design requires that the medium in the storage tank is constant temperature or the 32 SH/T 3528-2014 medium temperature is greater than 90°C, the storage tank bottom shall adopt heat insulation layer. 6.6.2 The heat conductivity coefficient and compressive strength of heat insulation materials shall comply with the design requirements. 6.6.3 The flatness of the heat insulation layer or surface layer after construction shall comply with the following requirements: a) There shall be no protruding edges and corners on the foundation surface in any direction; b) The surface flatness measured with stay wires from the center to all sides shall not exceed 25mm; c) The height difference between any two points within every 3m along the circumference shall not be greater than 20mm. 6.7 Construction of auxiliary facilities 6.7.1 The foundation of the operating platform and step of the storage tank shall be separated from the storage tank foundation, and the construction shall be carried out after the water filling test of the storage tank foundation. 6.7.2 The waterproof sealing of the storage tank bottom shall be carried out before the water filling test of the storage tank is completed and the storage tank body is not insulated. When there are no requirements in the design documents, waterproof ointment should be used as the sealing material. 6.7.3 Flexible waterproof materials should be used for secondary sealing after storage tank insulation. 6.7.4 A 10mm~15mm wide gap shall be reserved between the concrete apron and the storage tank foundation. A 10mm wide expansion joint should be set every 10m along the circumference of the storage tank foundation, and the joint shall be filled with stone matrix asphalt or asphalt sand. 7. Leak Test and Foundation Settlement Observation 7.1 Basic provisions 7.1.1 The settlement observation points of storage tank foundation shall be set evenly along the circumference. When there are no requirements in the design documents, the number of measuring points shall be set according to Table 7.1.1. 7.1.2 When there are no requirements in the design documents, the storage tank foundation 33 SH/T 3528-2014 settlement observation points can be directly buried or post embedded bars (Figure 7.1.2-1), or embedded parts (Figure 7.1.2-2). Table 7.1.1 Number of Storage Tank Foundation Settlement Observation Points Nominal capacity of Number of settlement Nominal capacity of Number of settlement storage tank (V) observation points storage tank (V) observation points m Piece m Piece 3 3 ≤2000 4 30000 < V≤50000 24 2000 < V≤5000 8 50000< V≤100000 24 5000 < V≤10000 12 100000< V≤150000 24 10000 < V≤30000 16 > 150000 32 Top elevation of foundation concrete Paint red on top Foundation concrete φ20 rivet Figure 7.1.2-1 Directly Buried or Post Embedded Bars Top elevation of foundation concrete Paint red on top Foundation concrete φ20 rivet Apply 2 layers of antirust paint to the weld bead with anchor plate δ= 8 Anchor plate 34 SH/T 3528-2014 Figure 7.1.2-2 Embedded Parts 7.1.3 The storage tank foundation settlement shall be observed by qualified surveyors at least twice a day. The settlement observation shall include the whole process before, during and after water filling, as well as during and within 48h after drainage of the storage tank, and records shall be made. 7.1.4 Level gauge and steel ruler should be used for settlement observation and measurement, and the measurement accuracy should be Level II leveling within the valid appraisal period. 7.1.5 Water filling of storage tank and foundation settlement observation shall comply with the provisions in Table 7.1.5. Table 7.1.5 Water Filling and Settlement Observation Standards of Storage Tank S/N Observation stage Water filling height (m) Standing Observation requirements time (h) Inspection methods The number of observation points shall 1 Before water filling - - comply with the provisions of Article 7.1.1, and the initial data shall be Level gauge recorded Control the water filling speed shall be H/2 24 controlled, and continue to fill the water when the differential settlement shall be Level gauge less than or equal to 5mm/d Control the water filling speed shall be 2 During 3H/4 24 water filling controlled, and continue to fill the water when the differential settlement shall be Level gauge less than or equal to 5mm/d Continue to fill water to the highest water level and stand for 48h. Drain the water H 48 when the settlement is still less than or equal to 5mm/d, and the total settlement Level gauge is less than or equal to the requirements of the design documents 3 During drainage - - Control the drainage speed and observe the foundation rebound twice a day Level gauge Note 1: H is the designed water filling height of the storage tank. Note 2: during water filling, the water filling speed shall not be greater than 3m/d. Note 3: during drainage, the drainage speed shall not be greater than 2m/d. 7.1.6 If any abnormality is found during settlement observation, water filling and drainage shall be stopped. 7.1.7 When the first storage tank foundation settlement in the tank farm meets the requirements, and the foundation structure and construction method of other storage tanks are exactly the same 35 SH/T 3528-2014 as those of the first storage tank, the two observations of water filling to H/2 and 3H/4 can be cancelled for the water filling test of other storage tanks. 7.2 Settlement observation results 7.2.1 The top surface of the foundation shall not be less than 300mm above the floor, and the leak aperture shall be above the floor. 7.2.2 The allowable value of final settlement difference in any diameter direction shall not exceed the provisions in Table 7.2.2. Table 7.2.2 Allowable Value of Final Settlement Difference of Storage Tank Foundation Unit: m Inner diameter of storage tank (D) Final settlement difference in any diameter direction Floater and covered floating roof tank Fixed roof tank D≤22 0.0070D 0.015D 22<D≤30 0.0060D 0.010D 30<D≤40 0.0050D 0.009D 40<D≤60 0.0040D 0.008D 60<D≤80 0.0035D - D>80 0.0030D - 8. Defect Disposal 8.1 If the concrete appearance quality has the common defects in Table 6.3.6.1, the construction unit shall deal with them in accordance with the provisions of SH/T 3510. 8.2 If the concrete appearance quality has the serious defects in Table 6.3.6.1, the construction unit shall put forward a technical treatment scheme, and the defects shall be treated after being approved by the supervision unit and the construction unit. 8.3 If the foundation bearing capacity test is unqualified or the foundation concrete strength is unqualified, the design unit shall put forward the treatment scheme. 8.4 When the height difference of the top surface of the ring beam of the storage tank foundation is greater than 13mm, the high-altitude concrete surface should be removed and polished without the exposed steel bars or loose concrete on the surface. After the top surface of the ring beam is roughened, it can be leveled with high-strength non-shrinkage grouting materials. 8.5 If the compactness of the asphalt sand insulating layer does not meet the requirements of design documents, the supervision unit shall determine the treatment scheme together with the design unit and the construction unit. 36 SH/T 3528-2014 8.6 After the leak test and settlement observation of the storage tank foundation is completed, if the foundation settlement does not comply with the provisions of Article 7.2 of this Specification, and the bottom plate of the steel storage tank is seriously deformed, and its hollowing area is greater than 5% of the storage tank bottom plate area, the construction unit shall draw the plane position drawing and elevation drawing of the settlement deviation, submit them to the design unit for putting forward the treatment scheme. 8.7 If the construction quality of storage tank foundation does not meet the requirements, it shall be re-accepted according to relevant regulations after treatment according to Articles 8.1 ~ 8.6 of this Specification. 9. Technical Documents for Hand over 9.1 During the acceptance of section project of storage tank subgrade and foundation, the construction unit shall submit the following technical documents: a) Material quality certificates and inspection and test reports; b) Positioning and measuring records of the project; c) Inspection records of foundation trench (pit); d) Ground improvement records; e) Registration form of qualified welder; f) Re-measurement records of allowable deviation items of storage tank foundation; g) Settlement observation records; h) Records of concealed works; i) Pile foundation construction / acceptance records; j) Composite foundation construction / acceptance records; k) Steel bar welding / mechanical connection test report; l) Compressive strength report of storage tank foundation concrete; m) Ex-factory certification of qualification of ready-mixed concrete; n) Concrete strength evaluation form; o) Quality accident handling report; p) List of engineering changes (attached with change order); q) Acceptance records of inspection lot; r) Acceptance records of item project; 37 SH/T 3528-2014 s) Acceptance records of section / subsection project; t) Process handover records. 9.2 If there is no provision in the contract, the technical documents for handover should be compiled according to SH/T 3503. When the form cannot meet the requirements, the form specified by the local Administrative Department of Construction can be used. 38 SH/T 3528-2014 Annex A (Normative) Classification of Section / Subsection Project, Item Project Table A S/N Classification of Section / Subsection Project, Item Project Section Name of subsection project project 1 Pile foundation Name of item project Pre-tensioned pre-stressed pipe pile and reinforced concrete pile Excavation and backfilling; Plain soil foundation, lime soil foundation, gravel foundation, dynamic compaction foundation, stone chip foundation and graded gravel foundation; cement 2 Foundation soil mixing pile composite foundation, cement fly-ash gravel pile composite foundation, sand pile composite foundation, vibroflotation pile composite foundation and lime soil compaction pile composite foundation Subgrade 3 and foundation Reinforced concrete foundation Concrete cushion, asphalt concrete cushion / asphalt sand layer, steel bar, formwork, concrete, post-cast strip, backfilling outside the ring wall Plain soil packing layer, lime soil packing layer, graded gravel 4 Packing layer packing layer, gravel packing layer, sand layer and impervious layer 5 Asphalt sand insulating layer 6 Heat insulation layer 7 Others Asphalt sand insulating layer Leveling layer and heat insulation layer Operating platform, apron, slope protection, storage tank bottom sealing 39 SH/T 3528-2014 Annex B (Informative) Cylinder Diesel Piling Hammer Parameter Table B Model of diesel hammer Impact body mass (t) Cylinder Diesel Piling Hammer Parameter 25# 32# ~ 36# 40# ~ 50# 60# ~ 62# 72# 2.5 3.2, 3.5, 3.6 4.0, 4.5, 4.6, 5.0 6.0, 6.2 7.2 5.2 ~ 6.2 7.2 ~ 8.2 9.2 ~ 11.0 12.5 ~ 15.0 18.4 1.5 ~ 2.2 1.6 ~ 3.2 1.8 ~ 3.2 1.9 ~ 3.6 1.8 ~ 2.5 300 301 ~ 400 401 ~ 500 501 ~ 550 551 ~ 600 Dense sand Dense sand Gross mass of hammer body (t) Common stroke (m) Applicable pile specification (diameter or side length) (mm) Rock and soil layer accessible to pile tip Hammer depth (mm/10 strikes) layer, hard soil layer, hard soil Strong Strong Strong layer and layer and strong weathered rock weathered rock weathered rock weathered rock weathered rock 20 ~ 40 20 ~ 50 20 ~ 50 20 ~ 50 30 ~ 70 600 ~ 1200 800 ~ 1600 1300 ~ 2400 1800 ~ 3300 2200 ~ 3800 Applicable range of design value of compression bearing capacity of pile shaft center (kN) Note: the pile hammer shall be selected according to the geological conditions of project, the design value of compression bearing capacity of pile shaft center, the pile specification, the embedded depth and other comprehensive factors; it is applicable to the working conditions of pile length of 15m~60m, pile tip entering a certain depth of rock and soil layer, and heavy hammer and low strike. 40 SH/T 3528-2014 Annex C (Normative) Quality Control Criteria for Packing Layer and Asphalt Sand Insulating Layer C.1 See Table C.1 for quality criteria for compacting factor of packing layer and asphalt sand insulating layer. Table C.1 Quality Criteria for Compacting Factor of Packing Layer and Asphalt Sand Insulating Layer Material type of packing layer, Inspection sand layer and methods K30 value a asphalt sand MPa/cm Number of Compacting factor inspection points insulating layer K30 Graded gravel 2.0 - Sand 1.0 ~ 1.2 - See Article 5.2.1 Sand - 0.94 ~ 0.96 Nuclear instrument Plain soil - 0.95 ~ 0.96 method Lime soil - 0.94 ~ 0.96 Asphalt sand - 0.95 Sand - 0.94 ~ 0.96 Plain soil - 0.95 ~ 0.96 Lime soil - 0.94 ~ 0.96 Graded gravel - 0.94 ~ 0.96 Irrigation method Sand - 0.94 ~ 0.96 See Articles 5.2.1 (sand cone method) Plain soil - 0.95 ~ 0.96 and 6.4.1.7 Lime soil - 0.94 ~ 0.96 Asphalt sand - 0.95 Cutting-ring method Drilling method a See Article 5.2.1 See Article 6.5.6 See Article 5.2.1 See Article 6.5.6 The K30 value of the first layer of cushion shall not be less than 0.8 times of the design value. C.2 See Table C.2 for thickness control criteria for packing layer and asphalt sand insulating layer. Table C.2 Thickness Control Criteria for Packing Layer and Asphalt Sand Insulating Layer Packing type of packing layer and asphalt sand Sand-gravel, sand, plain soil, lime soil, graded gravel Asphalt sand Thickness deviation Inspection methods Less than or equal to 10% of design thickness Less than or equal to 5% of design thickness 41 Number of inspection points Level gauge See Article 5.2.1 Borehole survey See Article 6.5.7 SH/T 3528-2014 Annex D (Informative) Trademark and Performance of Asphalt D.1 Asphalt can be divided into pavement petroleum asphalt, building petroleum asphalt and ordinary petroleum asphalt according to their uses; petroleum asphalt has the characteristics of water resistance, anti-corrosion, cohesiveness, high temperature stability, high ductility and high flash point. D.2 See Table D.2 for trademark and performance of asphalt. Table D.2 Quality index Trademark and Performance of Asphalt Pavement petroleum asphalt Building petroleum asphalt 100B 60A 60B 10 30 40 Penetration (0.1mm) 80 ~ 100 50 ~ 80 40 ~ 80 10 ~ 25 26 ~ 35 36 ~ 50 Ductility (cm) ≥60 ≥70 ≥40 ≥1.5 ≥2.5 ≥3.5 Softening point (℃) 42 ~ 52 45 ~ 55 45 ~ 55 95 75 60 Flash point (℃) ≥230 ≥230 ≥230 ≥230 ≥230 ≥230 Note 1: the penetration is the value measured under the condition of "25℃, 100g, 5s". Note 2: the ductility is the value measured under the condition of "25℃, 5cm/min". Note 3: the softening point is the value measured by the ring-and-ball method. D.3 When the asphalt trademark required in Article 6.5.2 of this Specification cannot be purchased, two brands of petroleum asphalt can be used for mixing, and the mix proportion can be estimated according to formula (D.3-1) and formula (D.3-2). When mixing, asphalt from the same production source shall be selected, that is, it is building petroleum asphalt or pavement petroleum asphalt. (D.3-1) (D.3-2) Wherein: Q1—mass ratio of asphalt with large penetration value, %; Q2—mass ratio of asphalt with small penetration value, %; T1—softening point of asphalt with large penetration value, ℃; T2—softening point of asphalt with small penetration value, ℃; T3—softening point of mixed petroleum asphalt, ℃. 42 SH/T 3528-2014 Bibliography [1] Zhang Zhong. Technical Manual for Testing of Building Materials [M]. Beijing: Chemical Industry Press, 2010 [2] Drafting Group of Building Construction Handbook. Building Construction Handbook (Fifth Edition) [M]. Beijing: China Architecture & Building Press, 2013 [3] Jia Qingshan. Storage Tank Foundation Engineering Handbook [M]. Beijing: China Petrochemical Press, 2002 [4] Jiang Zhengrong. Building Construction Calculation Handbook (Third Edition) [M]. Beijing: China Architecture & Building Press, 2013 __________________________________ 43 SH/T 3528-2014 Explanation of Wording in This Specification 1. In order to facilitate the different treatment when implementing the provisions of this Specification, the words with different strictness are explained as follows: 1) Words denoting a very strict or mandatory requirement: "Must" is used for affirmation; "Strictly Prohibited" is used for negation; 2) Words denoting a strict requirement under normal conditions: "Shall" is used for affirmation; "Shall Not" or "Should Not" is used for negation; 3) Words denoting a permission of slight choice, when conditions allow may first be chosen: "Should" is used for affirmation; "Should Not" is used for negation; 4) "May" is used to express the option available, sometimes with the conditional permission. 2. In case other relevant standards are specified for use in the provisions the implementation shall be written in the form of "shall comply with the requirements of" or "shall be executed according to". 44 SH/T 3528-2014 Petrochemical Industry Standard of the People's Republic of China Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry SH/T 3528-2014 Explanation of Provisions 2014 Beijing 45 SH/T 3528-2014 Revision Note SH/T 3528-2014 Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry was approved and issued by the Ministry of Industry and Information Technology in Announcement No. 47 on July 9, 2014. This Specification is revised on the basis of SH/T 3528-2005 Specification for the Construction and Acceptance of Petrochemical Steel Storage Tank Subgrade & Foundation. The editor in chief of the previous edition is the Fourth Construction Company of Sinopec (renamed as Sinopec Fourth Construction Co., Ltd.), and the main drafter is Wang Shuiping and Meng Ju. During the revision of this Specification, the drafting group has conducted extensive investigation and research on the steel storage tank subgrade and foundation constructed all over the country in recent years, analyzed the use of raw materials and products and construction technologies used in the storage tank subgrade and foundation construction under different geological and climatic conditions, summarized the storage tank subgrade and foundation construction in China, especially the practical experience in petrochemical steel storage tank subgrade and foundation engineering, and provided the important technical basis. In order to facilitate proper understanding and implementation of provisions of concerned persons in design, construction and scientific research units and universities, the drafting group of Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry explains the provisions of this Specification according to chapter and article and interprets the purpose, basis and matters need attention in the process of implementation of articles. However, the Explanation of Provisions does not have the same legal force as the main text, which is only used as the reference for users to understand and master related provisions in this Specification. 46 SH/T 3528-2014 Contents 4. General.......................................................................................................................................... 48 4.1 General provisions...................................................................................................................... 48 4.2 Type of storage tank foundations................................................................................................48 5. Storage Tank Foundation Construction........................................................................................ 48 5.1 General provisions...................................................................................................................... 48 6. Storage Tank Foundation Construction........................................................................................ 48 6.1 Excavation and backfilling..........................................................................................................49 6.3 Reinforced concrete foundation.................................................................................................. 49 6.4 Packing layer and impervious layer / sand layer in ring wall.....................................................50 6.5 Asphalt sand insulating layer...................................................................................................... 51 6.7 Construction of auxiliary facilities..............................................................................................52 7. Leak Test and Foundation Settlement Observation......................................................................52 8. Defect Disposal............................................................................................................................. 52 9. Technical Documents for Handover............................................................................................. 53 47 SH/T 3528-2014 Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry 4. General provision 4.1 Basic provisions 4.1.1 In order to strengthen the construction quality management, standardize the quality management behavior of construction enterprises and promote the construction enterprises to improve the quality management level, it is stipulated that the construction unit can establish relevant quality management system according to the quality management of the unit and the relevant requirements of GB/T 50430. 4.1.2 During the construction of underground works, there are often abnormal conditions with or without exploration data, so that the project cannot be carried out smoothly. In order to avoid losses, the construction unit is required to find out the distribution of concealed works within the construction scope. 4.2 Type of storage tank foundations This Article only aims to make the personnel who have just contacted the storage tank foundation construction know the foundation structure, and does not mean that it is limited to the forms listed herein. Due to the improvement of national environmental protection requirements, the seepage control practice of storage tank foundation is becoming more and more common. In order to improve the seepage control effect, geotechnical materials are given priority because they are easier to construct than other impervious materials and have good seepage control effect. 5. Storage Tank Foundation Construction 5.1 General provisions GB/T 50756 has been issued and implemented. In this revision, some contents of ground improvement have been deleted. This Specification refers to GB/T 50756 for the foundation construction and quality requirements. Therefore, the foundation construction and quality acceptance requirements meet the provisions of GB/T 50756 and this Specification. 6. Storage Tank Foundation Construction 48 SH/T 3528-2014 6.1 Excavation and backfilling 6.1.1 The construction survey and setting-out aim to calibrate the plane position, shape and elevation of the storage tank foundation designed on the drawing on the ground of the construction site, and guide the construction in the construction process, so that the project can be constructed according to the design requirements. Construction survey is not only the basis of the project, but also the key to the project quality. The checking of building line after setting-out is more important and cannot be a mere formality. 6.1.2 When the storage tank foundation is located in mountain or areas with high groundwater level, blasting and dewatering measures shall be taken for excavation. This Article especially emphasizes that excavation shall be carried out according to the approved construction technical documents. 6.1.4 The trench shall be inspected in time after the excavation, and the cushion shall be poured in time after the inspection. It is emphasized that the two timely measures are to prevent rainwater and groundwater from soaking the foundation trench. Timely understanding means no delay, immediately, at once. 6.1.7~6.1.9 The backfilling in these articles refers to the backfilling outside the ring wall of the storage tank foundation, and these articles define the sampling quantity for layered construction, layered compaction and compacting factor. 6.3 Reinforced concrete foundation 6.3.1.3 In recent years, there have been accidents of collapse during the installation of ring wall reinforcement or the removal of support system after installation, resulting in property and construction period losses in less serious cases and casualties in serious cases. Therefore, a support system is required for steel bar setting, which is not only to ensure the steel bar setting quality, but also an important safety protection measure. 6.3.4.3 Ensuring the construction quality of reinforced concrete ring wall is not only an important link to ensure that the storage tank foundation meets the requirements of design documents, but also a basis to ensure that the storage tank body is evenly stressed, and the foundation is fully stressed and evenly settled. In order to ensure the quality of the top surface of the ring wall, it is clear that the concrete on the surface of the ring wall is troweled, calendered and leveled at one time; it also specifies the requirements for secondary mortar leveling when the surface of the ring wall needs to be plastered. 49 SH/T 3528-2014 6.3.5 Mass concrete construction See GB 50496 for the definition of mass concrete. 6.4 Packing layer and impervious layer / sand layer in ring wall 6.4.1 General provisions At present, the packing in the ring wall of domestic storage tanks is mainly plain soil, lime soil, graded sand and graded gravel. The requirements for raw materials of the packing are relatively high, and the compacting factor is usually more than 0.96. In order to ensure the packing quality, it is necessary to focus on material selection and construction. As the main pressure bearing part of the steel storage tank foundation structure, the construction quality of the packing in the ring wall directly affects the safe operation of the storage tank. The packing in the ring wall shall be treated as a sub-part of the foundation acceptance. The material quality and compaction quality of the packing in the ring wall shall be regarded as an important quality control point for the storage tank foundation construction, and the construction unit and the supervision unit shall strictly control it. When the concrete strength of the ring wall is greater than C20, the ring wall can bear considerable lateral pressure generated by mechanical movement; the construction of internal and external ramps over the ring wall will not damage the ring wall; when the concrete strength of the ring wall is not greater than C20 or the amount of packing is large, in order to save the construction period, the construction technical documents shall be approved when the scheme of reserving door holes on the ring wall and carrying out storage tank core construction in advance is adopted. 6.4.2 Plain soil packing layer Moisture content is an important factor affecting the compaction quality. Under the action of the same compaction energy, the moisture content of the packing has a direct impact on the dry density (compacting factor) after compaction. Near the optimum moisture content, the dry density (compacting factor) after compaction is the largest. With the gradual increase or decrease of moisture content, the dry density (compacting factor) after compaction gradually decreases. With the gradual increase of the storage tank foundation diameter, the degree of mechanized construction used for the packing is higher and higher, which also gradually increases the reliability of the packing quality. Therefore, the area of inspection points is also increasing with the increase of the packing area specified in this Article. 50 SH/T 3528-2014 During the layered laying of packing, evidential sampling shall be carried out layer by layer, but evidential sampling shall also be conducted for the parts that are not convenient for mechanical compaction construction and are tamped manually, so as to achieve all-round monitoring in the whole process. 6.4.3 Lime soil packing layer During lime soil mixing, the lime digestion period is generally half a month, which must be reached, and then fine screening shall be conducted. Fine screening is also required for the soil mixing. Generally, it takes 3~5 days for stuffy lime with plastic cloth. If the digestion period does not expire, the lime particles will be too large and will expand after encountering water, so it cannot be compacted. 6.4.4 Graded gravel packing layer The maximum dry density of middle-level gravel in this Article shall be determined through compacting test according to the stone selected for actual construction. 6.4.8 Impervious layer This Article stipulates that geotechnical materials shall be rechecked before mobilization, and can be used only after passing the recheck; Test welding shall be conducted before geomembrane construction, and weld inspection shall be conducted according to the selected weld mode. Before the geomembrane construction, the sundries in the base course shall be cleaned, and there shall be not local concave-convex phenomenon on the base course surface. The cleaned base surface shall be dense and flat, and the flatness and cleanliness shall be controlled to prevent the impervious membrane from being pierced by sundries or leakage due to uneven compactness during use. 6.5 Asphalt sand insulating layer 6.5.6 The asphalt sand insulating layer has three main functions: anti-corrosion, anti-static and stress transfer; The large-scale storage tank foundation also provides a place for mechanical operation for the asphalt sand insulating layer construction, and ensures the asphalt sand insulating layer construction quality. Therefore, this Article specifies that the number of representative samples increases with the increase of area. 6.5.8 In order to meet the design elevation requirements, this Article stipulates that the difference between the measured elevation and the calculated elevation (calculated elevation: that is, the design elevation) is used to control the flatness of large-scale storage tank foundation. 51 SH/T 3528-2014 6.5.11 The asphalt sand insulating layer of the storage tank foundation is the bearing contact surface of the metal tank, and it is also an important measure to protect the storage tank bottom plate from electrochemical corrosion and prevent the capillary water rise of the sand layer. Therefore, the compactness of the asphalt sand insulating layer is very important. Similarly, the mix proportion of asphalt sand is also related to the final compaction effect of asphalt sand layer. The mix proportion specified in this Article is the dominant item. 6.7 Construction of auxiliary facilities The auxiliary facilities specified in this Article mainly refer to the operating platform, apron and bottom sealing of the storage tank. The operating platform, apron and bottom sealing of the storage tank are the operation items carried out after the leak test and settlement observation are qualified. Sealing is very key. Poor anti-corrosion and rust removal will lead to storage tank bottom corrosion, and poor joint between sealing material and heat insulation material will lead to rainwater entering the heat insulation layer through sealing. 7. Leak Test and Foundation Settlement Observation 7.1 General provisions 7.1.6, 7.1.7 This articles specifies the requirements and regulations for storage tank foundation settlement observation. After the storage tank is filled with water for 48h, if the maximum settlement value and uneven settlement value do not exceed the allowable value, it is considered that the foundation settlement test is qualified, and then the water can be drained. If the uneven settlement exceeds the allowable deviation value, it needs to immediately analyze the causes and take measures to stop water filling or drain to prevent foundation instability, In addition, it is also necessary to observe the leakage of the storage tank due to uneven settlement. 8. Defect Disposal The storage tank foundation defect disposal method is mainly based on the storage tank foundation settlement. An economic and reliable method with convenient construction and less impact shall be selected after analyzing the current stress state of storage tank body and foundation. During the specific implementation, calculation, test and checking calculation shall be carried out to ensure the safety and reliability of the repair scheme, and the durability after repair shall be considered. 52 SH/T 3528-2014 After the leak test and settlement observation of the storage tank foundation is completed, the concave-convex deformation or hollowing of the storage tank bottom plate is common. If the deformation error is not greater than the specified value, it is appropriate to maintain the current redistribution of the stress of the storage tank bottom plate; otherwise, it is necessary to deal with the concave-convex deformation or hollowing. The specific error limit is given. 9. Technical Documents for Handover Before the acceptance of storage tank foundation, the construction unit shall organize self-inspection and timely repair the parts with quality defects until they meet the acceptance standards specified in this Specification, and then the construction unit shall deliver it to the development / supervision unit for the acceptance. The acceptance shall be carried out in two aspects: one is that the technical data meet the requirements; the other is that the on-site measured data meet the requirements. The technical documents for handover shall be compiled and delivered to the development unit according to the provisions of the contract or SH/T 3503. 53 SH/T 3528-2014 Petrochemical Industry Standard of the People's Republic of China Specification for Construction and Acceptance of Steel Storage Tank Subgrade & Foundation in Petrochemical Industry SH/T 3528-2014 * Published by China Petrochemical Press Issued by Sinopec Engineering Standard Distribution Station Address: No. 58, Andingmenwai Street, Dongcheng District, Beijing Postcode: 100011 Tel: (010) 84271850 Telephone of Sinopec Standard Editorial Department: (010) 84289937 Telephone of Reader Service Department: (010) 84289974 http://www.sinopec-press.com E-mail: press@sinopec.com Copyright proprietary without reproduction * Book size 880×1230 1/16 Sheets 2.75 Words 70,000 Version 1 in May 2015 First Printing in May 2015 * ISBN: 155114 • 1032 Pricing: CNY 38.00 (Please identify the anti-counterfeiting mark on the cover when purchasing) 54
