Soil Mechanics Q/A

2. What are the uses of Direct shear test?

3. History of Engineering Materials?

Soil Constituents its types and properties

Atterberg's Limits

Constituents of Soil

Sand, Silt, Gravel, Stones

Types of Soil

Dry, Saturated, Partially saturated, Coarse, Fine, Organic, Gravel, Sand, Clay, Silt, Boulders, Cobbels, Peat

Properties

Voids ratio, Porosity, Degree of Saturation, Air Content, Water Content, Unit weight, Bulk unit weight, Specific Gravity, saturated unit weight

1. Liquid limit | Determine Liquid Limit of soil

2. Plastic limit | Determine Plastic Limit of soil

3. Shrinkage limit

4. Liquidity index

5. Flow index

6. Toughness index

• Stresses in Soil Mass
• Soil Analysis Compaction of Soil
• Earth Pressure
• Palm Islands Dubai
• Shear Strength of Soil
• Index Properties RCC Design Procedure
• Bearing Capacity
• Engineering Geology
• Soil Properties

Sieve Analysis & Particle Sizing Graphs

Classification of Soil

The grain-size characteristics of soils that are predominantly coarse grained are evaluated by a sieve analysis

A nest of sieves is prepared by stacking sieves one above the other with the largest opening at the top followed by sieves of successively smaller openings and a catch pan at the bottom of all the sieves
[Read More]

There are two soil classification systems in common use for engineering purposes.
... [Read More]

1. AASHTO
2. Unified Classification System
3. MIT Classification System

Soil Stress Analysis

Compaction of soil, its uses and effects

Both immediate and consolidation settlement analysis requires estimate of increase in pressure (ΔHσ) in the soil layers from the applied loads. Several methods are available to estimate the increase in pressure at any depth z from the applied load. ..... [Read More]

We will discuss:

1. 2:1 Slope method
2. Boussinesq Method.

Compaction is the application of mechanical energy to a soil to rearrange the particles and reduce the void ratio.. [Read More]

1. Purpose of compaction
2. Factors affecting compaction

There are three modes of shear failure, i.e. General, Local and Punching shear failures depending upon the compressibility of soil and depth of footing with respect to its breadth (i.e D/B Ratio). When the ultimate bearing capacity of the soil is reached, it may fail in one of the following three failure mode depending upon the type of soil and depth to width ratio of the footing (i.e. D/B)......... [Read More]

1. Pressure at rest
2. Active earth pressure
3. Passive earth pressure
4. Co efficients of earth pressure

Types of Soil Settlement

Methods of Determining Soil Bearing Capacity

A soil shear failure can result in excessive building distortion and even collapse. Excessive settlements can result in structural damage to a building frame nuisances such as sticking doors and windows, cracks in tile and plaster, and excessive wear or equipment failure from misalignment resulting from foundation settlements.

It is necessary to investigate both base shear resistance (ultimate bearing capacity) and settlements for any structure. In many cases settlement criteria will control the allowable bearing capacity...... [Read More]

• Analytic method i.e. through bearing capacity equations like using Terzaghi equation, Meyerhof equation, Hansen equation etc

• Correlation with field test data e.g. Standard penetration test (SPT), Cone penetration test (CPT) etc

• On site determination of bearing capacity e.g Plate load test, Pile load test

• Presumptive bearing capacity (recommended bearing capacity, in various codes).... [Read More]

Index Properties of Soil

Soil Bearing Capacity Analysis

The soil properties on which their classification and identification are based are known as index properties..... [Read More]

The index properties which are used are:

• Grain Size Distribution
• Consistency Limits
• Plasticity Index

Plastic saturated soils (silts and clays) usually have lower shear strength than non-plastic cohesion less soil and are more susceptible to bearing capacity failure.

For saturated plastic soils, the bearing capacity often has to be calculated for different conditionTotal Stress Analysis (Short term condition) that uses the un-drained shear strength of the plastic soil. Effective stress analysis (Long term condition that uses the drained shear strength parameters (c' & F') of the plastic soil).... [Read More]

Shear Strength of Soil

Determining Liquid Limit of Soil

Soils derive their strength from contact between particles capable of transmitting normal as well as shear forces. The contact between soil particles is mainly due to friction and the corresponding stress between the soil grains is called the effective stress s'.

Thus, the shear strength of a soil is mainly governed by the effective stress. Besides the effective stress between soil grains, the pore water contained in the void spaces of the soil also exerts pressure which is known as pore pressure, u. [Read More]

This testing method is used as an integral part of several engineering classifications systems to characterize the fine‑grained fractions of soils and to specify the fine‑grained fraction of construction materials. The liquid limit, plastic limit and plasticity index of soils are also used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, permeability, compactibility, shrink‑swell and shear strength..... [Read More]