A series of tri-axial compression tests conducted on sandstone samples reveal the following relationship between major and minor principal stresses σ₁ = 50 + 30σ₃ [stresses are in MPa)
The cohesion in MPa and angle of internal friction in degrees of sandstone respectively are

A. rock strength B. RQD C. ground water condition D. layers thickness

A. 5 - 10 KN B. 15 - 20 KN C. 50 - 60 KN D. 120 - 130 KN

A. point load test B. servocontrolled test C. displacement test D. post peak test

A. 1.25 B. 1.50 C. 2.25 D. 1.00