A consolidated, undrained tri axial test was carried out on a 73.0 mm diameter and 146.6 mm- long decomposed granodiorite sample at an initial water content of 26%. The sample was obtained from Palmerston Highway, North Queensland, Australia, to back-analyze a slope failure, and was initially consolidated under a cell pressure of 200 kPa and backpressure of 150 kPa. The drainage valve was dosed and the cell pressure was increased to 254 kPa when the pore water pressure increased to 182 kPa. Find Skempton's B-parameter. The nature of the soil sample is such that it was not possible to achieve a higher B value. The drainage valve was opened and the sample was consolidated further under the cell pressure of 254 kPa and backpressure of 150 kPa. At the end of consolidation, the drainage valve was dosed, locking in the backpressure in preparation for the undrained loading. The axial strain 8, additional vertical stress applied to the sample under undrained conditions Δσ', and the pore water pressure u measured during the test are summarized in the table given below: a. Plot the total and effective stress paths b. Plot. Δσ and pore water pressure against the axial strain on the same plot c. Find the peak and residual shear stresses at failure, and the corresponding values of Af.
A consolidated, undrained tri axial test was carried out on a 73.0 mm diameter and 146.6 mm-
long decomposed granodiorite sample at an initial water content of 26%. The sample was obtained
from Palmerston Highway, North Queensland, Australia, to back-analyze a slope failure, and was
initially consolidated under a cell pressure of 200 kPa and backpressure of 150 kPa. The drainage valve
was dosed and the cell pressure was increased to 254 kPa when the pore water pressure increased to
182 kPa. Find Skempton's B-parameter. The nature of the soil sample is such that it was not possible
to achieve a higher B value. The drainage valve was opened and the sample was consolidated further
under the cell pressure of 254 kPa
and backpressure of 150 kPa. At the end of consolidation, the drainage valve was dosed, locking in the
backpressure in preparation for the undrained loading. The axial strain 8, additional vertical stress
applied to the sample under undrained conditions Δσ', and the pore water pressure u measured during
the test are summarized in the table given below:
a. Plot the total and effective stress paths
b. Plot. Δσ and pore water pressure against the axial strain on the same plot
c. Find the peak and residual shear stresses at failure, and the corresponding values of Af.
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