Civil Engineering Reference
In-Depth Information
Figure 7.6
Interpretation of shear tests.
Henkel (1962) in their standard text. Most of these are still widely used today, although
many of the instruments have been superseded by modern electronic devices.
The basic features of the conventional triaxial tests are shown in Fig. 7.7. The soil
sample is a cylinder with height about twice the diameter; sizes commonly used in the
United Kingdom are 38 and 100 mm diameters (originally 1
2
and 4 in). The sample
is enclosed in a thin rubber sleeve sealed to the top platen and to the base pedestal
by rubber O-rings. This is contained in a water-filled cell with a cell pressure
c
.
A frictionless ram passes through the top of the cell and applies a force
F
a
to the top
platen; this is measured by a proving ring or by a load cell either inside or outside
the cell, as shown. Axial displacements are measured by a displacement transducer
attached to the loading ram. The cell and sample assembly are placed inside a loading
σ
Figure 7.7
Conventional triaxial apparatus.
