Concept explainers
Find the pore water pressure at failure for the second specimen.
Find the Skempton’s pore pressure parameter at failure.
Answer to Problem 10.13P
The pore water pressure at failure for the second specimen is
The Skempton’s pore pressure parameter at failure is
Explanation of Solution
Given information:
Specimen 1:
The confining pressure of the clay
The deviator stress at failure
Specimen 2:
The confining pressure of the clay for consolidated undrained triaxial test is
The deviator stress at failure
Calculation:
The consolidated drained triaxial test was conducted for normally consolidated clay (specimen 1) and the consolidated undrained triaxial test was conducted for specimen 2.
Consider the consolidated drained triaxial test (specimen 1).
Find the major principal effective stress at failure
Here,
Substitute
Find effective friction angle
Here,
Consider that the specimen as normally consolidated clay. Hence the effective stress cohesion
Substitute 0 for
Rearrange the Equation.
Substitute
Consider the consolidated undrained triaxial test (specimen 2).
Find the major principal stress
Here,
Substitute
Show the formula for major principal effective stress.
Here,
Substitute
Show the formula for minor principal effective stress.
Substitute
Calculate the pore water pressure using the Equation (1).
Substitute Equation (2), (3) in Equation (1) and
Therefore, the pore water pressure at failure for specimen 2 is
Find the Skempton’s pore pressure parameter
Substitute
Therefore, the Skempton’s pore pressure parameter at failure is
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Chapter 10 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
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