(a)
Find whether the statement “For normally consolidated clays
(a)
Answer to Problem 10.1P
The statement, “For normally consolidated clays
Explanation of Solution
According to Mohr-Coulomb failure criteria, the value of effective stress cohesion
The effective stress cohesion is approximated as 0 for normally consolidated clay.
Therefore, the statement, “For normally consolidated clays
(b)
Find whether the statement “Peak friction angle cannot be less than the ultimate friction angle” is true or false.
(b)
Answer to Problem 10.1P
The statement, “Peak friction angle cannot be less than the ultimate friction angle” is true.
Explanation of Solution
When the load is applying on a dense sand, the resisting shear stress increases with shear displacement until it attains a failure stress of
The shear stress gradually decreases with increases of shear displacement after reaches the failure stress. The continuous increase of shear displacement finally attains a constant value, then it is called ultimate shear strength.
Express the peak shear strength as follows:
Find the peak friction angle
Express the ultimate shear strength as follows:
Find the ultimate friction angle
Refer to Figure 10.6, “Determination of shear strength parameters for a dry sand using the results of direct shear stress” in the textbook.
From the Figure 10.6, the peak friction angle
The statement, “Peak friction angle cannot be less than the ultimate friction angle” is true.
(c)
Find whether the statement “The stress strain plot of a dense sand is similar in shape to that of a normally consolidated clay” is true or false.
(c)
Answer to Problem 10.1P
The statement, “The stress strain plot of a dense sand is similar in shape to that of a normally consolidated clay” is false.
Explanation of Solution
Sketch the stress-strain relationship for loose and dense sand as shown in Figure 1.
Refer to figure 1
The stress-strain curve for the loose sand is same as that of the normally consolidated clay.
The stress-strain curve for the dense sand is same as that of the over consolidated clay.
The statement, “The stress strain plot of a dense sand is similar in shape to that of a normally consolidated clay” is false.
(d)
Find whether the statement “Sensitivity of a clay can be less than one” is true or false.
(d)
Answer to Problem 10.1P
The statement, “Sensitivity of a clay can be less than one” is false.
Explanation of Solution
The sensitivity of clays is defined as the ratio of the unconfined compressive strength of clay in undisturbed to remoulded state.
The sensitivity of clay varies from 1 or
The statement, “Sensitivity of a clay can be less than one” is false.
(e)
Find whether the statement “
(e)
Answer to Problem 10.1P
The statement, “
Explanation of Solution
In consolidated undrained test, the shear strength parameters for over consolidated clay based on effective stress c and
In an unconsolidated undrained test, the failure envelope for the total stress lies on the horizontal line.
Hence,
The statement, “
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Fundamentals of Geotechnical Engineering (MindTap Course List)