Q$4)$ In the limit equilibrium conditions, point A that is on the failure surface is

shown in Figure $6.$ Based on this point, please write the Factor of Safety $($FOS$)$

Equations changing with the shear strength of the soil for

$($a$)$ Total Stress conditions $($please consider UU Triaxial data$),$ and

$($b$)$Effective stress conditions $($please consider CD Triaxial data$).$

Note that in the limit equilibrium conditions, the FOS is assumed to be

constant for the entire failure surface. Hence, the average FOS is indicated by

the ratio of available to required shear strength $($ required$).$

Figure $6.$ Failure surface of A point in Limit Equilibrium Conditions