Section Cover Page
Section 02319
Trench Excavating and Backfilling
2000-03-22
Use this Section to specify requirements which apply specifically to excavating, backfilling, and
compacting trenches required for installation of underground services, occurring within and outside
perimeter of buildings or structures. Underground services may include pipes, ducts, ductbanks,
conduit, cable, wire, etc.
This Master Specification Section contains:
.1
This Cover Sheet
.2
Specification Section Text:
1.
1.1
1.2
1.3
1.4
1.5
1.6
General
Intent
Section Includes
Related Requirements
Related Work Specified in Other Sections/Divisions
Coordination
Unit Prices
2.
2.1
Products
Fill Materials
3.
3.1
3.2
3.3
3.4
3.5
3.6
Execution
Excavation
Placement and Compaction of Fill Material
Utility Crossings
Pipe Trench Width
Pipe Trench Width Schedule
Backfilling Schedule
BMS Basic Master Specification
Alberta Infrastructure
Master Specification System
Page 0
Section 02319
Trench Excavating and Backfilling
Page 1
Plan No:
Project ID:
1.
General
1.1
INTENT
.1
Read this Section in conjunction with:
.1
.2
.3
1.2
[Earthwork Testing:
Fill Materials:
Earthwork General Requirements:
Section 02010.]
Section 02056.
Section 02305.
SECTION INCLUDES
.1
1.3
This Section includes requirements for excavating, backfilling, and compacting trenches
required for installation of underground services, occurring within and outside perimeter
of buildings or structures. Underground services may include pipes, ducts, ductbanks,
conduits, cable and wire.
RELATED REQUIREMENTS
.1
1.4
Mechanical and Electrical
Service Connections:
Division 1.
RELATED WORK SPECIFIED IN OTHER SECTIONS/DIVISIONS
.1
.2
.3
1.5
Pipe bedding for pipe utility systems:
Pipe bedding for mechanical services:
Pipe bedding for electrical services:
Section [02 ]
Division 15.
Division 16.
COORDINATION
.1
1.6
Coordinate work specified in this Section with pipe bedding and other related work
specified in other Sections.
UNIT PRICES
.1
Trench Excavating And Backfilling:
.1
Unit Description: Temporary access, excavating, dewatering, sheathing and
shoring, [support, of existing utilities], backfilling and disposal of excess and
waste material.
.2
Unit of Measurement: Metre length of trench.
Section 02319
Trench Excavating and Backfilling
Page 2
Plan No:
Project ID:
SPEC NOTE: Include following paragraph for gravity sewer or other graded utility lines where
payment is to be made for different depth ranges.
.3
Method of Measurement: Where depth of utility line varies, depth shall be
measured from original grade elevation at centre line of utility to utility invert.
Three depth measurements, one at each manhole and one at mid-point between
manholes, will be taken for each section of line. A section is defined as the
centreline distance between successive manholes. The average of the three
measurements shall be the depth for that section.
SPEC NOTE: Include the following, Topsoil Excavation, when no other site work is being carried
out.
.2
.3
.4
Topsoil Excavation:
.1
Unit Description: Stripping and [stockpiling] [disposal off-site].
.2
Unit of Measurement: [Cut measure] [truck measure] [stockpile measure].
[
] Fill Material:
.1
Unit Description: [
.2
Unit of Measurement: [Excavated quantity, measured by [cubic metre] [truck]
[tonne].] [Compacted in-place quantity, measured by [cubic metre] [truck] [tonne]
[square metre measured parallel to surface for specified thickness].]
[
] Fill Material:
.1
Unit Description: [
.2
Unit of Measurement: [Excavated quantity, measured by [cubic metre] [truck]
[tonne].] [Compacted in-place quantity, measured by [cubic metre] [truck] [tonne]
[square metre measured parallel to surface for specified thickness].]
2.
Products
2.1
FILL MATERIALS
.1
] material as specified in Section 02056].
] material as specified in Section 02056].
Refer to Section 02056 for fill material product specifications.
Section 02319
Trench Excavating and Backfilling
Page 3
Plan No:
Project ID:
3.
Execution
3.1
EXCAVATION
.1
Excavate trenches to alignment and depth indicated or required and to uniform width,
sufficiently wide to provide adequate working room. For pipe trenches, comply with Pipe
Trench Width Schedule.
.2
Grade and shape pipe trench to give uniform and even bearing for each length of pipe.
Dig bell holes at each joint as required.
3.2
PLACEMENT AND COMPACTION OF FILL MATERIAL
.1
Backfill trenches using fill materials as specified in Backfilling Schedule.
.2
Place fill materials in layers not exceeding loose thickness specified in Backfilling
Schedule.
.3
Uniformly compact each layer of fill to minimum percentages of Standard Proctor
Density specified in Backfilling Schedule.
.4
Use care in backfilling to avoid damage or displacement of services.
3.3
UTILITY CROSSINGS
.1
Install crossings as indicated on Drawings.
.2
Comply with requirements [of crossing permit issued by utility company] [and]
[requirements of utility company].
3.4
PIPE TRENCH WIDTH
.1
Except as otherwise specified, minimum and maximum trench widths, up to a point
300 mm above top of pipe [or top of highest pipe in the case of multiple pipes], shall be
as specified in Pipe Trench Width Schedule.
.2
Maximum trench widths indicated in Pipe Trench Width Schedule exclude an allowance
for shoring.
.3
Minimum trench width for "Rock Excavation in Trenches" shall be 1 m.
.4
Trench width at any point shall not be less than trench width at any depth below such
point.
Section 02319
Trench Excavating and Backfilling
Page 4
Plan No:
Project ID:
3.5
PIPE TRENCH WIDTH SCHEDULE
No. of Pipes
Minimum
Trench Width
Maximum
Trench Width
Single pipe,
850 mm diameter
or less
300 mm greater than
external pipe
diameter
450 mm greater than external
pipe diameter or 750 mm total
trench width, whichever is
greater
Single pipe,
greater than
850 mm diameter
300 mm greater than
external pipe
diameter
600 mm greater than
external pipe diameter
Multiple pipes,
side by side
300 mm greater than
horizontal dimension
across outer edges of pipes
600 mm greater than horizontal
dimension across outer edges of
pipes
3.6
BACKFILLING SCHEDULE
Max. Lift
Thickness
Minimum
Compaction
Location
Fill Material
Under interior
slabs-on-grade
[
]
[
] mm
[
]%
Under exterior
slabs-on-grade
[
]
[
] mm
[
]%
Under landscaped
areas
[
]
[
] mm
[
]%
Under paved areas
[
]
[
] mm
[
]%
[
[
]
[
] mm
[
]%
[
]
[
] mm
[
]%
]
Other locations
END OF SECTION