Geotechnical Testing Laboratory


Determination of grain size distribution by means of a hydrometer

The hydrometer method of particle size analysis calculates the physical proportions of these soil particles based on their settling rates in an aqueous solution and identifies three size classes: sand (2000 – 50 µm), silt (50 – 2.0 µm), and clay < 2.0 µm.

Sieves – for determination of grain size distribution for natural & engineering properties

Particle size distribution is determined by weighing the material retained on each of the sieves and dividing these weights by the total weight of the sample.

Determination of soil paste alkalinity by means of PH & conductivity

pH is determined by measuring the hydrogen ion activity in an aqueous solution and the electrical conductivity indicates the amount of soluble (salt) ions in the soil. The determination of electrical conductivity (EC) is made with a conductivity cell by measuring the electrical resistance of a 1:5 soil: water suspension.

Determination of Triaxial stress and strain calculations and shear characteristics

A triaxial shear test is a common method to measure the mechanical properties of many deformable solids, especially soil (e.g., sand, clay) and rock, and other granular materials or powders.

An oedometer test is a kind of geotechnical investigation performed in geotechnical engineering that measures a soil’s consolidation properties. Oedometer tests are performed by applying different loads to a soil sample and measuring the deformation response.

Direct shear tests are performed with three different shear box sizes (60 × 60, 100 × 100, and 300 × 300 mm). Results indicate that the peak shear strength and the peak friction angle decrease with increasing the shear box size while residual shear strength is constant.


Porous and perforated plates are placed on the top and bottom surface of the specimen which allows free drainage during the test. The whole shear box is placed inside a container (carriage box) which is filled with water and enables the test specimen to be submerged during the test.

Conductivity meter- Determination of alkalinity of a soil paste Ph. & conductivity.

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