Geotechnical Investigation

Course Objective

The aim of this course is to impart to the students, a clear idea about how a geotechnical investigation program is to be planned and executed. It enables the students an in-depth knowledge of the various methods of geotechnical investigation and the field tests to be conducted in different situations.

Prescribed Syllabus

Module 1

Introduction and practical importance – Objectives of soil exploration– Planning of a sub-surface exploration program –Collection of existing information, reconnaissance, preliminary and detailed investigation – I.S. and other guidelines for deciding the number, size, spacing, and depth of boreholes Methods of exploration – Open pits – Auger boring- -Wash boring, percussion drilling, rotary drilling

Module 2

Sounding methods Standard Penetration Test – Procedure –corrections to be applied to observed N values – Numerical examples -Factors influencing the SPT results and precautions to obtain reliable results – Merits/drawbacks of the test – Correlations of N value with various engineering and index properties of soils Static Cone Penetration Test – Procedure – Merits/drawbacks –Correlation of static CPT results with soil properties -Dynamic Cone Penetration Test – Brief Procedure – Merits/drawbacks –Critical comparison of SPT, static CPT, and dynamic CPT

Module 3

Geophysical methods – Seismic refraction method – Procedure, uses, limitations – Solution of numerical problems to estimate the velocity of seismic waves and the thickness of the upper layer of a two-layered soil system – Electrical resistivity method – Electrical profiling and electrical sounding – Procedure, uses, limitations. Stabilization of boreholes, Groundwater level estimation.

Module 4

Soil sampling – Undisturbed, disturbed, and representative samples –Chunk and tube samples – Factors affecting sample disturbance and methods to minimize them –Area ratio – Inside clearance – Outside clearance – Recovery ratio –Ball check valve – Numerical Problems -Handling and transportation of samples – Extrusion of samples Types of samplers – Thin-walled sampler – Piston sampler – Split spoon sampler – Methods for collection of sand samples from beneath the water table – Core retainers

Module 5

Pressure meter test – Procedure –Uses – limitations, Flat Dilatometer Test (Brief only)Plate load test – Procedure, uses, and limitations – modulus of subgrade reaction- Solution of numerical problems using plate load test data Rock core sampling, Rock Quality Designation, Core Recovery Ratio –Bore log – Soil profile – Sub-soil investigation report

Text Books (T) 

T1. Gopal Ranjan and Rao A.S.R., “Basic and Applied Soil Mechanics”, New Age International (P) Limited, New Delhi, 2002

T2. Venkata Ramaiah, “Geotechnical Engineering”, Universities Press (India) Limited, Hyderabad, 2000.

Reference Books (R)

R1. Arora K.R., “Geotechnical Engineering”, Standard Publishers Distributors, New Delhi, 2006.

R2. Joseph E. Bowles, „Foundation Analysis and Design‟, Mc. Graw Hill Inc., New York, 1988.

R3. Purushothamaraj P., Soil Mechanics and Foundation Engineering, Dorling Kindersley(India) Pvt. Ltd., 2013.

R4. Terzaghi K. and R. B. Peck, Soil Mechanics in Engineering Practice, John Wiley, 1967

Course Outcomes

At the end of the course, students will be able to  

CO1: Understand the procedure, applicability, and limitations of various methods of geotechnical investigation

CO2: Make engineering judgments and take appropriate decisions related to geotechnical investigations

CO3: Understand the procedure and applications of penetration tests and geophysical tests for exploration of the soil profile

CO4: Choose the right soil sampling technique and analyse the dependability of samples collected

CO5: Understand the procedure and applications of field load tests and rock quality indices

Mapping of Course Outcomes with Program Outcomes and Program Specific Outcomes