# GEOTECHNICAL LABORATORY TESTS Reading time: 1 minute

Geotechnical laboratory tests consists of number of tests for the properties of soil. These tests are done to find out the suitability of soil for the construction projects.

### DIFFERENT TYPES OF SHEAR TESTS AND DRAINAGE CONDITIONS

The following tests are used to measure the shear strength of the soil Direct shear test Triaxial compression test Unconfined compression test Vane shear test Depending upon the drainage conditions, there are three types of tests Unconsolidated-Undrained condition Consolidated –...

### CALIFORNIA BEARING RATIO TEST

AIM: To determine the California Bearing Ratio value of the subgrade soil. APPARATUS: Loading machine-any compression machine can operate at constant rate of 1.25mm per minute can be used. Cylindrical moulds- moulds of 150mm diameter and 175mm height provided with...

### SPECIFIC GRAVITY OF SOLIDS BY PYCNOMETER METHOD

TO DETERMINE SPECIFIC GRAVITY OF SOLIDS BY PYCNOMETER METHOD Theory: The Pycnometer method can be used for determination of the specific gravity of solid particles of both fine grained and coarse grained soils. The specific gravity of solids is determined...

### SPECIFIC GRAVITY OF SOLIDS BY DENSITY BOTTLE METHOD

TO DETERMINE SPECIFIC GRAVITY OF THE SOLIDS BY DENSITY BOTTLE METHOD Theory; The specific gravity of solid particles is the ratio of the mass density of solids to that water. It is determined in the laboratory using the relation: Where...

### DETERMINATION OF WATER CONTENT OF SOIL

A) By oven dry method Theory: The water content (w) of a soil sample is equal to the mass of water divided by the mass of solids. Where M1=mass of empty container with lid, M2= mass of the container with...

### DRY DENSITY OF SOIL BY WATER DISPLACEMENT METHOD

TO DETERMINE THE DRY DENSITY OF A SOIL SAMPLE BY WATER DISPLACEMENT METHOD Theory: A soil specimen of regular shape is coated with paraffin wax to make it impervious to water. The total volume (V1) of the waxed specimen is...

### IN-SITU DRY DENSITY BY SAND REPLACEMENT METHOD

TO DETERMINE IN-SITU DRY DENSITY BY SAND REPLACEMENT METHOD Theory: A hole of specified dimensions is excavated in the ground. The mass of the excavated soil is determined. The volume of the hole is determined by filling it with clean,...

### DRY DENSITY OF SOIL BY CORE CUTTER METHOD

TO DETERMINE DRY DENSITY OF SOIL BY CORE CUTTER METHOD Theory: A cylindrical core cutter is a seamless steel tube. For determination of the dry density of the soil, the cutter is pressed into the soil mass so that it...

### PARTICLE SIZE DISTRIBUTION OF SOIL BY SEIVING

TO DETERMINE THE PARTICLE SIZE DISTRIBUTION OF A SOIL BY SEIVING Theory: The soil is sieved through a set of sieves. The material retained on different sieves is determined. The percentage of material retained on any sieve is given by...

### PARTICLE SIZE DISTRIBUTION BY HYDROMETER METHOD

TO DETERMINE THE PARTICLE SIZE DISTRIBUTION BY HYDROMETER METHOD Theory: Hydrometer method is used to determine the particle size distribution of fine-grained soils passing 75 sieve. The hydrometer measures the specific gravity of the soil suspension at the centre of...

### THE LIQUID LIMIT OF SOIL TEST

TO DETERMINE THE LIQUID LIMIT OF A SOIL SPECIMEN Theory: The liquid limit of a soil is the water content at which the soil behaves practically like a liquid, but has small shear strength. It flows to close the groove...

### DETERMINATION OF SHRINKAGE LIMIT OF REMOULDED SOIL

TO DETERMINE THE SHRINKAGE LIMIT OF A SPECIMEN OF THE REMOULDED SOIL Theory: The shrinkage limit is the water content of the soil when the water is just sufficient to fill all the pores of the soil and the soil...

### PERMEABILITY OF SOIL BY CONSTANT HEAD PERMEAMETER

TO DETERMINE PERMEABILITY OF SOIL BY CONSTANT HEAD PERMEAMETER. Theory: The coefficient of permeability is equal to the rate of flow of water through a unit cross section area under a unit hydraulic gradient. In the constant head permeameter, the...

### VARIABLE HEAD PERMEABILITY TEST OF SOIL

TO DETERMINE THE PERMEABILITY OF A SOIL SPECIMEN BY THE VARIABLE HEAD PERMEAMETER Theory: The variable head permeameter is used to measure the permeability of relatively less pervious soils. The coefficient of permeability is given by Where = initial head,...

### CONSOLIDATION TEST OF SOIL

TO DETERMINE THE CONSOLIDATION CHARACTERISTICS OF A SOIL SAMPLE Theory: Consolidation of a saturated soil occurs due to expulsion of water under static, sustained load. The consolidation characteristics of soils are required to predict the magnitude and the rate of...

### SHEAR STRENGTH OF SOIL BY DIRECT SHEAR TEST

TO DETERMINE THE SHEAR STRENGTH OF A SANDY SOIL SPECIMEN BY DIRECT SHEAR TEST Theory: Shear strength of a soil is its maximum resistance to shearing stresses. The shear strength is expressed as Where c’ = effective cohesion, = effective...

### UNCONFINED COMPRESSIVE STRENGTH OF COHESIVE SOIL

TO DETERMINE THE UNCONFINED COMPRESSIVE STRENGTH OF COHESIVE SOIL Theory: The unconfined compressive strength () is the load per unit area at which the cylindrical specimen of a cohesive soil falls in compression. Where P= axial load at failure, A=...

### COMPACTION OF SOIL PROCTOR’S TEST

TO DETERMINE THE COMPACTION CHARACTERISTICS OF A SOIL SPECIMEN BY PROCTOR’S TEST Theory: Compaction is the process of densification of soil by reducing air voids. The degree of compaction of a given soil is measured in terms of its dry...

### TRIAXIAL SHEAR STRENGTH TEST

TRIAXIAL SHEAR STRENGTH TEST ON SOIL This is the most widely used and is suitable for all types of soils. A cylindrical specimen, generally having a length to diameter ratio of 2, is used in the test and is stressed...

### VANE SHEAR TEST ON SOIL

VANE SHEAR TEST ON SOIL The vane shear test apparatus consists of four stainless steel blades fixed at right angle to each other and firmly attached to a high tensile steel rod. The length of the vane is usually kept...