Question

Shear strength of a rock joint is not dependent on

• A. Applied normal stress
• B. Applied shear stress
• C. Friction angle of the joint plane
• D. Cohesion of the joint plane

Hint:

For a rock joint, \[ \boxed{ \tau=c+\sigma_n\tan\phi. } \] Thus, shear strength depends on cohesion, normal stress, and friction angle—not on the applied shear stress.

Answer 1

The Correct Option is B

Step 1: Recall the Mohr--Coulomb equation for joint shear strength. The shear strength of a rock joint is \[ \tau = c+\sigma_n\tan\phi, \] where \[ c=\text{cohesion}, \] \[ \sigma_n=\text{normal stress}, \] and \[ \phi=\text{friction angle}. \]

Step 2: Identify the independent quantity. From the above equation, shear strength depends on \[ c,\quad \sigma_n,\quad \phi, \] but it does not depend on the applied shear stress itself. Hence, \[ \boxed{\text{Applied shear stress}} \] is the correct answer. Therefore, \[ \boxed{(B)} \] is the correct answer.