Direct Shear Test Apparatus

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 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. Following pages give details of both hand operated and motorized versions of direct shear test apparatus conforming to different Indian Standard Specifications.

Direct Shear Apparatus, Hand Operated IS : 2720 (Part XIII)
The unit confirms to IS2720. It has a hand operated horizontal loading system for shearing the specimen. Hangers are provided for creating normal stress.
It comprises :-
(i) Shear box assembly, 60 mm square, complete with a U-bracket, guide pins and spacing screws, made of brass.
(ii) Gripper assembly consisting of two plain grid plates, two perforated grid plates, one base plate and one loading pad, all made of brass.
(iii) Two porous stones, each 6 mm thick, fitting the shear box
(iv) Shear box housing of brass, complete with two ball roller strips.
(v) Loading unit with normal loading of 8 kg/cm2 on 60 mm square specimen. vi) Specimen cutter for a specimen size of 60 mm x 60 mm x 25 mm.
(vii) Set of weights to give a normal stress up to 3 kg/cm2 through lever, comprising 4 of 0.05 kg/cm2, 1 of 0.1 kg/cm2, 1 of 0.2 kg/cm2, 3 of 0.5 kg/cm2 and 1 of 1 kg/cm).
Complete as above but without dial gauges and proving ring.

Direct Shear Apparatus, 12 speed, Motorized IS: 2720 (Part XIII) IS:11229
The unit is same as above except that it is motorized. It is provided with a turret type gear box to get 12 different constant rates of strain i.e 1.25,0.625,0.25,0.125,0.05, 0.025, 0.01, 0.005, 0.002, 0.001, 0.0004, and 0.0002 mm/min. and arrangements to carry out residual shear strength tests. Suitable for operation with 220V, 50 hz, single-phase supply.