L.

D COLLEGE OF ENGINEERING AHMEDABAD

PRESENTATION
ON
PNEUMATIC SHEAR TEST
(SII-3714308)

PRESENTED BY:
SR NO. NAME ROLL NO.
1 PATEL DARSHAN S. 714310
2 QURAISHI HAFSAA I. 714314
3 PATEL RAHUL 714315
4 SHAIKH TOKIRHUSEN 714317
I.
5 SHUKAL SPARSH K. 714318
6 DHANJAL SIMRANJEET 714319
CONTENT
INTRODUCTION
COMPONENTS
SAMPLE PREPARATION
WORKING PROCEDURE
OBSERVATIONS & DATA LOGGING
CALCULATIONS
ADVANTAGES AND DISADVANTAGES
INTRODUCTION
 COMPONENTS USED FOR THE
TEST:
 Shear box Shear box container
Base plate with cross groves on its top
Porous stones (2 Nos)
Plain Grid plates (2Nos)
Perforated grid plates (2Nos)
Loading pad with steel ball
Pneumatic loading assembly
Loading frame with loading yoke
Proving ring Dial gauges (2 Nos)
Weights Tampering
Rod ,Spatula ,Rammer ,Sample
SAMPLE PREPARATION
The testing procedure can be summarized in the
following stages:
1. Weigh the initial mass of the soil
2. Measure the height and diameter of the shear box
3. Place the shear box inside the shearing device
4. Stabilize the bottom part of the shear box by fixing
the 2 screws
5. Assemble the shear box (put porous stone and the
gripper disk together)
6. Put the sample inside the box and place a filter
paper, a porous stone and the loading cap on top of
it
7. Weight the mass of the remaining soil to derive the
mass of the sample
 WORKING PROCEDURE:
After the sample is prepared….
Shear box with the prepared specimen is placed in the load
frame chamber.
Assembling the vertical load frame.
Re-engage the shear device through the load cell.
Remove the guiding pins.
Select a seating load and read the dial indicator to note the
initial reading before beginning the consolidation and then
after measure the vertical displacement due to consolidation
Set all dial gauges to zero.
Set up the pneumatic system for normal load by required
adjustments and set the normal load to be maintained during
the test.
Check alignments for the assembly before starting the test.
Set a selected rate of the shearing device and start the shearing
stage.
Take reading measures frequently depending on the shearing
rate until the shear stress peaks and falls.
To stop the test full closure is applied which traps the
pressure, further the vent valve is opened and slight load is
applied to release all pressure.
After the pressure in the system is removed, the Shear box can
be taken apart and the sample can be inspected.
OBSERVATION AND DATA
COLLECTION
Calculate the volume of the sampler and weigh the sampler.
After completing three layers, level the top layer and weigh the soil sampler with soil and
find the weight of wet soil.
Calculate the water content of soil.
Calculate the density of soil to confirm the obtainment of required density.
Normal stress 0.5 kg/cm2 L.C=....... P.R.C=.........
Horizontal Gauge Vertical Dial Proving ring Horizontal Dial Shear deformation Vertical gauge Vertical deformation= Proving Shear stress = div. col. (8) x
Reading gauge Reading Reading gauge Reading Col. (4) x Least reading Initial div.in col.6 x L.C of reading Initial proving ring constant Area of
(1) Initial reading div. count of dial Reading dial gauge reading the specimen (kg/cm2)
(2) (3)
gauge
(5) (6) (7) (8) (9)
(4)

0                
25                
50                
75                
100                
125                
150                
175                
200                
250                
300                
400                
500                
600                
700                
800                
900                
ADVANTAGES
 Direct measurement of shear strength
 Basic principles are easily understood
 Relatively easy testing procedure
 Simple and easy sample preparation
 Quick consolidation procedure due to the small thickness of the specimen
 Almost all soil types can be tested
 Both peak and residual shear strength is determined
 Residual strength tests are applicable
 Partially saturated soil specimens can be tested with the appropriate equipment
DISADVANTAGES
Shear strength is measured only on a predefined shear plane.
Distribution of stresses along the shear plane is not uniform.
Only total stresses are applied, except on the testing of dry granular material, as pore water
pressures cannot be measured.
There is no control of the drainage, therefore only drained tests can be performed.
The continual decrease in the contact surface of the two halves during the test produces a
small error on the shear and normal stress and affects the Mohr-Coulomb failure envelope.
This error is generally ignored.
THESE ARE THE CODES WE
USED FOR REFERENCE:
IS 2720 - Part 13 - 1986 : Methods of Test for soil, Direct Shear Test.
BS1377 - Part 7 - 1990 : British Standard Methods of test for Soils for civil engineering
purposes, Part 7 - Shear strength tests (total stress)
ASTM D3080-04 : Standard Test Method for Direct Shear Test of Soils Under Consolidated
Drained Conditions
AS1289.6.2.2 – 1998 : Methods of testing soils for engineering purposes – Method 6.2.2:
Soil strength and consolidation tests – Determination of the shear strength of a soil – Direct
shear test using a shear box.
THANK YOU!