Page 17 - Grp3-Soil magazine (Final-Vid ver)
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TESTS FOR DETERMINATION OF
SHEAR STRENGTH PARAMETERS ( A ) D I R E C T S H E A R T E S T
(A) DIRECT SHEAR TEST
(A) DIRECT SHEAR TEST
This test is conducted in two stages:
Consolidation stage: Involves the
consolidation of the specimen under the
same vertical stress as that which will be
applied during shearing. When this stage
finishes, the consolidation parameters can be
obtained.
Shearing stage: The specimen is sheared at a
constant speed which depends on the
consolidation parameters determined from
Figure 1: Direct Shear Test
the consolidation stage. The speed must be
such that sufficient time is allowed for the soil
to expel the excess pore water and therefore
provide drained conditions.
Results of both stages are plotted on graph.
Graph of shear stress vs shear
displacement (refer Figure 2a)
Figure 2 (a): Graph of Shear Stress vs Shear Displacement
Graph of shear stress vs normal stress is
plotted to obtain c’ and ϕ’ (refer Figure 2b)
Direct Shear Test Procedure
Direct Shear Test Procedure
Figure 2 (b): Graph of Shear Stress vs Normal Stress for (a) sand, (b) clay
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