Direct Shear Test of Soil, Strength Test

Direct Shear Testing Equipment

The direct shear test is used to measure the shear strength properties of soil. In many engineering projects, the cohesion and internal angle of friction are needed to determine soil strength. The direct shear test is a laboratory method used to quickly predict these factors in a field situation.

This test can be performed in three different drainage conditions:

1. Unconsolidated-Undrained Test: drainage is not permitted during the application of both normal stress and shear stress
2. Consolidated-Undrained Test: the specimen is allowed to fully consolidate under applied normal stress and then sheared at a high rate of strain so that pore water may not drain out
3. Consolidated-Drained Test: the specimen is allowed to fully consolidate under applied normal stress and then sheared at a low rate of strain so that pore water may drain out

During the direct shear test, shear strength is measured by exposing the specimen to shear stress. The deformation that occurs, the shear strain, is measured at frequent intervals to produce a stress-strain curve. Several specimens are tested, and the results are plotted to determine the soil’s internal angle of friction strength parameters.

Humboldt provides both the necessary equipment and software to perform direct shear tests. These include:

Direct shear testing machines are used to apply both normal and shear stress on the specimen.
NEXT Direct Shear Software provides tabulated test data, graphs and all test-specific calculations in real time.
Accessories include shearboxes, weights, and sample prep supplies.

Visit our geotechnical testing and engineering landing page for more in-depth information.