Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil it is composed of a variable mixture of small particles such as sand, silt and/or clay. The determination of the engineering properties of the soil and rock strata that affect the performance of the structure and determination of the in situ properties are generally done by performing field tests such as standard penetration test, cone penetration test etc.

This Section of Laboratory under Assam Road Research & Training Institute deals with sub soil investigation and various Laboratory tests to be performed on sub-soil samples. This section deals with testing of soil properties such as Specific gravity, Moisture Content of Soil, Mechanical properties of soil, particle size analysis, Shear Strength of Soil etc. The test results of such samples help in solving various problems related to various Foundation Design and Construction, Design of underground and earth retaining structures, Pavement Design etc.

Tests conducted at Soil-Survey Section with approved rates are as follows: