Shear Box Test

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Definition - What does Shear Box Test mean?

Shear box test is a testing method used to determine the shear strength of a soil sample. Since granular soils cannot be retrieved undisturbed, the soil is re-compacted inside a shear box.

The soil’s friction angle is then determined by direct shear and the tests are carried out under saturated conditions. This test is performed as per ASTM D3080 and is performed on three or four specimens of undisturbed soil samples.

Trenchlesspedia explains Shear Box Test

Shear strength testing is carried out for analyses of short term and long term slope stability. The shear box is a rectangular box divided into two halves horizontally. Two stacked rings hold the samples and contact each other at mid-height of the sample.

Confining stress is applied to the sample vertically and the upper ring is pulled laterally through a specified strain or till the sample fails. A stress-strain curve is drawn based on the load applied and strain is induced at regular intervals.

Usually, the sample is saturated prior to testing or can be run at site moisture content.

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