CE4003 Geotechnical Engineering Subject Code Credits GPA/NGPA CE4003 4.0 GPA Subject Title Total Hours Geotechnical Engineering 55hrs Lectures Lab/Assignt 10hrs PreRequisites CE 3003-Soil Mechanics and Engineering Geology Aims: To Calculate the changes in stress resisted by soil due to external point loads, line loads and loaded areas To develop an understanding of the principle of settlement and the distinct difference between immediate settlement and consolidation. To be able to calculate potential consolidation settlements due to loading and dewatering Understand the concepts of ground improvement by pre-consolidation with or without vertical drains. To develop an understanding of the processes of geotechnical investigation, determination of engineering characteristics of soil in situ and methods of undisturbed sampling To develop an understanding of the concepts of shear strength of soils, time dependence, evaluation of shear strength of soils in the laboratory under different drainage conditions and application to different field conditions To demonstrate different mechanisms of slope failure, evaluation of safety margin by different methods under limit equilibrium approach and time dependence of stability, To demonstrate methods of enhancing the stability of slopes and rectification of failed slopes. To demonstrate the ability to determine the relevant strength parameters of soils for foundation design, evaluate the allowable bearing pressure of soil using bearing capacity equations, select an appropriate shallow foundation for a given structure to suit the subsurface condition, estimate the immediate and consolidation settlement of a shallow foundation and the ability to identify the difficulties associated with the construction of shallow foundations To demonstrate the ability to determine the relevant strength parameters of soils for foundation design, ability to select a suitable type of a foundation for a given structure to suit the subsurface condition and the environmental constraints, ability to evaluate the carrying capacity of a pile considering the effects of negative skin friction, ability to estimate the expected settlement of a single pile subjected to vertical axial loading and the ability to identify the difficulties associated with construction of bored piles. Ability to identify the importance of drainage behind a retaining wall, ability to use Coulombs trial wedge approach to determine the design lateral earth pressure on a gravity retaining wall, ability to evaluate the safety of the retaining wall against different failure modes and the ability to propose recommendations to improve the stability of the retaining wall To demonstrate the ability to determine the depth of embedment of an embedded retaining wall,evaluate the short-term and long-term stability of an embedded retaining wall, evaluate the maximum bending moment of the retaining wall and the ability to discuss the limitations of the conventional design procedure Learning Outcomes: Ability to estimate settlements due to consolidation due to constructions and/or dewatering Ability to design improvements in soft clay through pre-consolidation. To be able to plan a appropriate geotechnical investigation for a basic civil engineering project To be able to apply the shear strength concept in geotechnical problems; To be able to assess the stability of existing slopes, design new cut or fill slopes and propose methods for rectification of failed slopes To be able to plan a appropriate geotechnical investigation for a basic civil engineering project To be able to apply the shear strength concept in geotechnical problems; To be able to assess the stability of existing slopes, design new cut or fill slopes and propose methods for rectification of failed slopes Ability to understand basic mechanical and physical behaviour of rock masses and design of rock slopes; Ability to design shallow foundations Ability to design deep foundations Ability to design gravity type and embedded type retaining walls Syllabus Consolidation: Concept of consolidation, Terzaghi’s theory for one dimensional consolidation, Determination of consolidation characteristics in the laboratory, Stress distributions in the soils, Estimation of amount and rate of settlement due to loading, consolidation due to dewatering, secondary consolidation, improvement of soft clays is preloading. Geotechnical Investigations Methods of geotechnical investigation, methods of advancing a borehole in soil, methods of coring in rock, in situ tests, methods of obtaining undisturbed samples, borehole logging, idealization of a soil profile with borehole data. Shear Strength Relevance of shear strength of soils, Mohr Coulomb failure criterion, Drained and undrained conditions, Determination of shear strength in the laboratory by Direct shear test and triaxial tests, applicability of different types of triaxial tests, Pore water pressure development and Skempton’s law, Stress invariants and stress paths, Vane shear test, Shear strength of unsaturated soils Stability of Soil Slopes: Different modes of slope instability, Drained and undrained behavior, shallowtranslational slides, Analysis of rotational slides by friction circle method, Taylor’s chats,Bishop and Morgenstern charts, Ordinary slices method, Bishop’s method of slices,concept of probability of failure, Stabilization of slopes. Earth Retaining Structures: Different types of earth retaining structures, Evaluation of earth pressures byRankin’s theory and by Coulomb’s trial wedge approach, Effect of wall roughness,effects of pore water pressure and seepage, codes for the design of earth retainingstructures, Design of gravity retaining walls to resist different failure modes, Design ofembedded retaining walls by free earth support method and fixed earth supportmethod. Shallow Foundations Design of centrally and eccentrically loaded footings with vertical and inclined loads; Use of insitu soil test results in shallow foundation design; Settlement estimation of shallow foundations using the theory of beams on elastic medium and the theory of consolidation. Deep Foundations Construction quality controlling and quality assurance of deep foundations; Design of vertically loaded single pile; Design of pile groups subjected to vertical loads, estimation of settlement of piles. Retaining walls Different types of earth retaining structures, Evaluation of earth pressures by Rankine’s theory and by Coulomb’s trial wedge approach, Effect of wall roughness, effects of pore water pressure and seepage, codes for the design of earth retaining structures, Design of gravity retaining walls to resist different failure modes, Design of embedded retaining walls by free earth support method and fixed earth support method. Assessment: Laboratory tests Consolidation Test Direct shear Test Triaxial Test Continuous Assessment -30% Final Examination (3hrs paper) -70% References: Principles of Geotechnical Engineering by Borja M Das, PWS-KENT Publishing Company. Principles of Foundation Engineering Borja M Das, PWS-KENT Publishing Company. Soil Mechanics for Civil and Mining Engineers by G N Smith, Granada Publication Soil Mechanics – R F Graig, Van Nostrand Reinhold Company Ltd