1. GEOTECHNICAL ENGINEERING – I B.E. IVTH SEMESTER
Prof. R. G. Bade

2. UNIT 1
1. Introduction: Formation of soil, residual & transported soil, major deposits found in India, soils generally used in practice such as sand, gravel, organic soil, clay, Betonies, black cotton soil etc. Introduction to clay mineralogy.
2. Phases of soil: Various soil weight & volume inter-relationship. Density index, methods of determining in situ density.

3. What is Geotechnical Engineering?
Soil:
Natural aggregates of mineral grains, loose or moderately cohesive inorganic or organic in nature that have the capacity of being separated by means of simple mechanical processes.
Geotechnical Engineering:
A unique combination of science, experience, judgment and a passion for understanding the uniqueness and variability of ground conditions resulting from the forces of nature.
It is the art of determining the properties of unseen and variable materials to provide a facility that perform as expected at acceptable level of risk and at an optional cost.

4. Application of civil engineering to earthen materials
What is Geotechnical Engineering?
Application of civil engineering to earthen materials
Soil
Rock
Groundwater

5. What is the difference between
soil and dirt?
If you can grow food in it, get paid to analyze it, or get college credit for playing with it, it’s soil; otherwise it’s dirt.

6. Branches of Geotechnical Engineering
Soil Mechanics
Rock Mechanics
Foundation Engineering
Geoenvironmental Engineering
Geotechnical Earthquake Engineering
Geologic Engineering

7. Soil Behavior Introduction
“Concrete and Steel are textbook materials; Soil is not.”

8. Soil is heterogeneous
Homogeneous
Heterogeneous

9. Soil is anisotropic
Anisotropic
Isotropic

10. Soil is non conservative
Before
After
Conservative
Before
After
Nonconservative
(but that doesn’t mean it’s liberal)

11. Soil is nonlinear
Stress
Strain
Linear
Stress
Strain
Nonlinear

12. SOIL FORMATION
Weathering is the process of the breaking down rocks. There are two different types of weathering. Physical weathering and chemical weathering. In physical weathering it breaks down the rocks, but what it's made of stays the same. In chemical weathering it still breaks down the rocks, but it may change what it's made of. For instance, a hard material may change to a soft material after chemical weathering.
STAGE STAGE STAGE 3
STAGE 4

13. SOIL PROFILE

14. SOIL TYPES SOIL TYPES RESIDUAL SOIL SEDIMENT SOIL ALLUVIUM SOIL
LACUSTRINE SOIL
MARINE SOIL
PARTICULAR SOIL
EXPANSIVE SOIL
ORGANIC SOIL
COLLAPSIBLE SOIL
QUICK CLAY

15. BASIC CHARACTERISTIC PARTICLE BONDING
THE PARTICLE BONDING IS VERY WEAK SO RELATIVELY EASY TO GOING TO CHANGE AND HAVE NON-LINEAR BEHAVIOUR AND CHARACTERISTIC
SHAPE, SIZE AND STRUCTURE OF SOIL PARTICLE
Cohesive Soil
Non-cohesive Soil

18. PHYSICAL PROPERTIES OF SOIL
BASIC DEFINITION AND PHASE RELATIONS
Solid
Water
Air
Soil is generally a three phase material
Contains solid particles and voids
Voids can contain liquid and gas phases
Phase
Volume
Mass
Weight
Air Va
Water Vw Mw Ww
Solid Vs Ms Ws

19. Units Length metres Mass tonnes (1 tonne = 103 kg) Density t/m3
Weight kilonewtons (kN)
Stress kilopascals (kPa) 1 kPa = 1 kN/m2
Unit weight kN/m3
Accuracy Density of water, rw = 1 t/m3
Stress / Strength to 0.1 kPa

20. Weight and Unit weight
Force due to mass (weight) more important than mass
W = M g
Unit weight

21. Specific Gravity This is defined by
Gs is useful because it enables the volume of solid particles to be calculated
from mass or weight

22. Voids Ratio
It is not the actual volumes that are important but rather the ratios between the volumes of the different phases. This is described by the voids ratio, e, or porosity, n, and the degree of saturation, S.
The voids ratio is defined as
and the porosity as
The relation between these quantities can be simply determined as follows
Hence

23. Degree of Saturation
The degree of saturation, S, has an important influence on soil behavior.
It is defined as
The phase volumes may now be expressed in terms of e, S and Vs
Vw = e S Vs
Va = Vv – Vw = e Vs (1 – S)