Geotechnical laboratory

Geotechnical laboratory of AlmatyGeoCentre LLP carries out soil tests and determines their physical, hydrophysical, mechanical and chemical properties.

Basic physical, hydrophysical and chemical properties that are generally used in constructiona are as follows: 

– natural moisture content;

– plastic limits;

– liquidity index;

– soil grading;

– bulk density;

– natural void ratio;

– permeability coefficient;

– groundwater chemistry;

– salt content of soils;

– groundwater and soil aggressiveness to metals and concrete;

 

Our geotechnical laboratory determines a wide range of soil mechanical properties using the highly sophisticated automated equipment.

 

Compression

Soil sample compression in the odometer with freely drainable pore liquid. This test is used to determine the deformation properties of soils, such as the modulus of total deformation, the modulus of elasticity, as well as the coefficients of primary and secondary consolidation.

The principle attraction of the test lies in the simplicity of its preparation and execution, however, it has the disadvantage of impossibility of the lateral expansion in the odometer and, as a consequence, lack of lateral strain monitoring. In view of this, the results of deformation modulus determination shall be corrected based on the results of other laboratory methods or field tests.

 

Single-plane shear test

Direct shear test of soil samples is the most common and the most important method used to determine the soil strength. The analysis of bearing capacity of foundation soils of buildings and structures is based on the soil strength. Also, the value of the angle of internal friction and specific cohesion are the most important parameters, without which it is impossible to estimate the stability of slopes, fills, dams, open pit walls, etc.

Our geotechnical laboratory is testing soils by the in-plane shear method according to the following procedures:

unconsolidated undrained procedure (quick shear test for unstabilized soil) – strength parameters shall be determined at overall stresses;

consolidated drained procedure (slow shear test for stabilized soil) – strength parameters shall be determined at effective stresses.

 

Triaxial compression test of soil

Stabilometer test is the most accurate method used to determine the strength and deformation properties of soil. It is possible to monitor the principal stresses practically independently, measure volumetric deformations, control drainages, create and measure pore pressure during the test, which allows to obatain a wealth of information about the soil behavior at various loading paths.

 

Interpretation of test results for nonlinear analysis in PLAXIS/MIDAS software packages

Software packages with modern soil models such as the Hardening Soil, the top range nonlinear model of soil behavior, are now rapidly gaining popularity. A fairly large number of laboratory tests are required in order to provide such a model with high-quality input data, however, saving in construction expenses due to more precise analysis may be repaid many times over.

 

Our geotechnical laboratory conducts tests and provides interpretation of their results to be used in modern nonlinear models of soil behaviour.