In a direct shear test, the failure of the soil sample in shear is caused along a predetermined plane. Test is performed as per IS 2720 part XIII The normal load, strain and shearing force are measured directly during the test. It is also used to estimate residual stress of soil. The direct shear testing apparatus utilizes a square box divided horizontally into two halves. The box containing the sample is placed in a water jacket and subjected to constant normal load while a horizontal force is applied till the specimen fails along the plane of juncture of the two halves. A number of specimens are tested under different loads and from the data obtained the angle of internal friction and shearing strength of the soil can be evaluated.

The apparatus comprises of the following.
Loading Unit:
Supplied with load yoke with direct and lever system for applying load. Normal stress capacity 8 kg/sq. cm. Load is applied either directly or through a counter balanced detachable lever. Provision is made for the load to be applied either through a steel ball recessed in the loading pad or direct through a boss on the pre calibrated loading yoke. The loading unit is provided with V strips and roller strips for frictionless movement of shear box housing.
Shear Box Assembly:
Comprising direct shear box in two halves for a square specimen size 60 x 60 x 25mm one pair of plain gripper plates, One pair of perforated gripper plates, one pair of porous stones, one top of loading pad.
Shear Box Housing:
Accommodates the direct shear box assembly.
Complete with two ball roller strips.
Specimen cutter: for cutting 60 x 60 x 25 mm.
Specimen form larger samples. Set of weights to give a normal stress of 3kg/sa.cm. Through larger as following :

To give kg/cm. sq.      Qty.
0.05                          4 nos.
0.1                            1 no.
0.2                            1 no.
0.5                            3 nos.
1.0                            1 no.

Complete set as above but without proving ring. 

• IS:2720 (Part XIII)
• IS:11229

The apparatus comprises of the following.
Loading Unit:
Supplied with load yoke with direct and lever system for applying load. Normal stress capacity 8 kg/sq. cm. Load is applied either directly or through a counter balanced detachable lever. Provision is made for the load to be applied either through a steel ball recessed in the loading pad or direct through a boss on the pre calibrated loading yoke. The loading unit is provided with V strips and roller strips for frictionless movement of shear box housing.
Shear Box Assembly:
Comprising direct shear box in two halves for a square specimen size 60 x 60 x 25mm one pair of plain gripper plates, One pair of perforated gripper plates, one pair of porous stones, one top of loading pad.
Shear Box Housing:
Accommodates the direct shear box assembly.
Complete with two ball roller strips.
Specimen cutter: for cutting 60 x 60 x 25 mm.
Specimen form larger samples. Set of weights to give a normal stress of 3kg/sa.cm. Through larger as following :

To give kg/cm. sq.      Qty.
0.05                          4 nos.
0.1                            1 no.
0.2                            1 no.
0.5                            3 nos.
1.0                            1 no.

Complete set as above but without proving ring. 

Essential Accessories:
High sensitivity compression proving ring. Cap 200kg. One consolidation dial gauge 0.01mm x 25mm and one strain dial gauge 0.01mm x 25mm
Optional Extras:
Additional set of weights to give a normal stress of 5 kg/cm2. Soil sampler for 60mm x 60mm specimen and test forms pad of 50.
Spares:
Porous stone for 60mm x 60mm size sample available in pairs.
Unit is electrically operated to give the following 12 rates or strains. 1.25, 0.625, 0.25, 0.125, 0.05, 0.025, 0.01, 0.005, 0.002, 0.001, 0.004 and 0.0002 mm/min. The apparatus is suitable for operation on 230 Volts Single Phase A.C. Supply.