Concept explainers
State whether the following are true or false.
- a. The higher the friction angle, the higher the value of K0.
- b. K0 is greater for normally consolidated clays than overconsolidated clays.
- c. Active earth pressure coefficient is greater than the passive one.
- d. The larger the cohesion, the larger is the depth of the tensile cracks in clays in active state.
- e. Lateral earth pressures increase linearly with depth.
(a)
Whether the statement “The higher the friction angle, the higher the value of
Answer to Problem 14.1P
The given statement is
Explanation of Solution
Write the equation of coefficient of earth pressure at rest
Here,
Find the coefficient of earth pressure at rest when
Substitute
Find the coefficient of earth pressure at rest when
Substitute
Tabulate the values of coefficient of earth pressure at rest with two different drained friction angles of
Drained friction angle, | Coefficient of earth pressure at rest, |
0.5 | |
0.134 |
Table 1
Refer Table 1.
The coefficient earth pressure at rest
Therefore, the given statement is
(b)
Whether the statement “
clays” is true or false.
Answer to Problem 14.1P
The given statement is
Explanation of Solution
The value of over consolidated ratio (OCR) is a whole number.
Write the relationship between earth pressure at rest for over consolidated clay
The multiplication of square root of over consolidated ratio (OCR) with earth pressure at rest for normal consolidated clay gives the earth pressure at rest for over consolidated clay. Hence, the value earth pressure at rest for over consolidated clay is greater than the earth pressure at rest for normal consolidated clay.
Therefore, the given statement is
(c)
Whether the statement “Active earth pressure coefficient is greater than the passive one” is true or false.
Answer to Problem 14.1P
The given statement is
Explanation of Solution
Write the equation of active earth pressure coefficient
Here,
Find the active earth pressure coefficient
Substitute
Write the equation of passive earth pressure coefficient
Substitute
Tabulate the values of active and passive earth pressure coefficients with corresponding friction angle of
Friction angle, | Active earth pressure coefficient, | Passive earth pressure coefficient, |
0.333 | 3 |
Refer Table 1.
The active earth pressure coefficient
Therefore, the given statement is
(d)
Whether the statement “The larger the cohesion, the larger is the depth of the tensile cracks in
clays in active state” is true or false.
Answer to Problem 14.1P
The given statement is
Explanation of Solution
Write the equation of depth of tensile crack
Here,
From Equation (4), cohesion
Therefore, the given statement is
(e)
Whether the statement “Lateral earth pressures increase linearly with depth” is true or false.
Answer to Problem 14.1P
The given statement is
Explanation of Solution
Write the equation of lateral earth pressure
Here,
The lateral earth pressure equation is a linear equation and the lateral earth pressure
Therefore, the given statement is
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Chapter 14 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
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