What are the standard internal dimensions of a shear box as per this IS code?

The internal plan dimensions are 60 mm x 60 mm, and the internal depth of each half is 25 mm. (Clause 4.1)

What material should the shear box be made of?

A corrosion-resistant material such as brass, gunmetal, or stainless steel. (Clause 3.1)

What is the specified thickness for the porous stones used in the shear box?

The thickness should be 6.0 ± 0.5 mm. (Clause 4.3)

What is the maximum allowable gap between the upper and lower halves of the shear box?

The clearance should not exceed 0.25 mm. (Clause 4.1.2)

IS 11229

: 1985

shear box for testing soils

CurrentSpecializedSpecificationGeotechnical · Soil and Foundation Engineering

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This standard specifies the material requirements, dimensions, and constructional details for the shear box apparatus used in conducting direct shear tests on soil samples. It covers the main components including the shear box assembly, porous stones, grid plates, and loading pad.

shear box for testing soils

Quick Reference Values

Internal dimensions of shear box60.0 ± 0.1 mm square

Internal depth of each half of box25.0 ± 0.1 mm

Thickness of porous stones6.0 ± 0.5 mm

Gap between two halves of boxNot to exceed 0.25 mm

Diameter of perforations in grid plate2.0 ± 0.1 mm

Porosity of porous stonesNot less than 35 percent

Practical Notes

This standard only defines the apparatus; the procedure for conducting the direct shear test is detailed in IS 2720 (Part 13).

Maintaining the tight clearance (max 0.25 mm) between the two halves of the box is critical for accurate shear test results, as a larger gap can introduce significant errors.

The condition of the porous stones is crucial; they should be regularly checked for clogging and saturation to ensure proper drainage during a consolidated drained test.