For the data given in Example 11.15, determine the reduction in passive earth pressure for a curved surface of failure if 8 = 30°.
Solution
For a plane surface of failure P from Eq. (11.76) is
It is clear from the above calculations, that the soil resistance under a passive state gives highly erroneous values for plane surfaces of failure with an increase in the value of S. This error could lead to an unsafe condition because the computed values of P would become higher than the actual soil resistance.
