Civil Engineering Reference
In-Depth Information
Figure 10.9
Power law peak strength envelope for shear tests.
and these are shown in Fig. 10.9. Equation (10.14) describes the peak strength of soil
in shear tests. The voids ratio or water content is contained within the critical stress
σ
c
through Eq. (9.8). Equation (10.14) contains two parameters
φ
c
and
B
which are
material parameters and they depend only on the nature of the soil grains.
For triaxial tests the power law peak strength envelope is
M
p
p
p
c
β
q
p
p
c
=
(10.16)
Equation (10.16) shown in Fig. 10.10 describes the peak strength of soil in triaxial tests.
The voids ratio or water content is contained with in the critical stress
p
c
through
Eq. (9.13). Equation (10.16) contains two parameters
M
and
β
which are material
parameters and they depend only on the nature of the soil grains.
Figure 10.11(a) shows points
a
,
b
and
c
which are the peak strengths in three shear
tests on the same soil. The test results have been normalized with respect to the critical
stress
σ
c
to take account of different water contents. The curved envelope which passes
close to the three points, through the origin and through the critical state point is a
power law curve. A linear Mohr-Coulomb envelope has been drawn as a best fit to
Figure 10.10
Power law peak strength envelope for triaxial tests.
