DIGITAL DIRECT SHEAR APPARATUS-SINGLE SPEED

Complies with IS : 2720 (PART 13) 1986 / IS : 11229 - 1985

Introduction

The test covers the determination of consolidated drained or undrained shear strength of a soil material by direct shear. Normal Load, Strain and shearing force are measured directly during the test. Specimen size 60mm square can be tested. The complete system consist of Microprocessor based Touch screen PLC-HMI, Load Frame, Mould assembly or shear box made of brass with accessories, Shear box housing with two ball strips, specimen cutter with set of weights to give normal stress of 3 kg/cm² through lever.

Salient Features :

1. Password protected operation of touch screen Panel
2. The screen displays load, shear stress, horizontal and vertical displacements, Independent taring and calibration of each Channel
3. Facility for selection of measurement unit KN, KG

LOAD FRAME :

The Load Frame is silent and rigid to not to transmit any vibration to the sample during the test or cause friction between the loading frame and shear box housing assembly. The floor mounted Load frame consist of loading head driven by electric motor with gearbox to ensure variable speed from 0.0002mm/min to 1.25 mm/min. Strain rate will remain constant irrespective of the stress. 2 KN Load cell is used for Load measurement while 2 Nos. 0.001 mm sensitivity LVDT is used for vertical and horizontal measurements. The load frame has V-strips on which the shear box housing rests. The lead screw connected to the shear box housing helps application of shear stress.. Suitable for specimen of size 60 x 60 x 25mm square.

Normal stress is applied to the specimen by utilizing a weight hanger, a lever arm (amplification ratio 10:1) and a vertical loading yoke. Hanger can receive slotted weights which is amplified by the lever arm and transferred to the specimen by the vertical loading yoke as a normal force up to 3 kg/cm²

The system receives the output signal from the sensors i.e. Load cell and Displacement Sensors attached to the apparatus. The data of all three channels of Test can be transferred to computer through RS-485 and can be online monitored. (software at extra cost)

Working on 220/230 Volts, AC single Phase.

SHEAR BOX AND HOUSING :

It comprises of Shear box assembly, 60 mm square, complete with a U-bracket, guide pins and spacing screws, Made of brass, Gripper assembly consisting of two plain grid plates, two perforated grid plates, one base plate, one loading pad, all made of brass. Two porous stones, each 6 mm thick are also supplied. Shear box housing of brass, complete with two ball roller strips. Specimen cutter and mould extracting tool also supplied along with.

Salient Features:

1. Aesthetical appearance
2. Powder coated exterior body
3. Tactfully designed complete system
4. Multiple reversal type system
5. Motorized, Twelve speed design
6. Electrically operated to give twelve (12) different constant rate of strain at 1.25, 0.625, 0.125, 0.05, 0.01, 0.005, 0.002, 0.001, 0.0004 and 0.0002mm/min.
7. Supplied with loading yoke with direct and lever for applying load.
8. Normal stress capacity 8 Kg/Sq. cm
9. Load is applied either directly or through a counter balanced detachable lever.
10. 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.
11. The loading unit is provided with V-strips and roller strips for frictionless movement of shear box housing.
12. Suitable for operation on 230 Volt,50 Hz, Single Phase, A.C. Supply

Consists of following accessories:

1. Loading unit with normal loading of 8 kg/cm2 on 60 mm square specimen
2. Shear box assembly for 60 mm x 60 mm x 25 mm thick specimen
3. Shear box housing, complete with two ball roller strips, made of gunmetal material
4. Two porous stones, each of 6 mm thick, fitting to the shear box
5. Gripper assembly consisting of 2 plain grid plates, 2 perforated grid plates, one base plate and one loading pad, all made of gunmetal.
6. Specimen cutter for a specimen size of 60 mm square & 25 mm thick specimen
7. Set of weight to give normal stress of 3 kg/cm2 through lever as follows.
8. To give kg/cm2:
9. 0.05 - 4 Nos.
10. 0.1 - 1 Nos.
11. 0.2 - 1 Nos.
12. 0.5 - 3 Nos.
13. 1.0 - 1 Nos.