3. A horizontal circular cavity with a diameter of 2R,=6m is excavated in the rock mass at a depth of 400m below the sur
Posted: Sat May 21, 2022 3:24 pm
3. A horizontal circular cavity with a diameter of 2R,=6m is excavated in the rock mass at a depth of 400m below the surface. It is assumed that the natural stress of the rock mass is hydrostatic pressure state, and the natural density of the rock mass is p=2.7g/cm'. Please calculate: (20 points) (1) The redistributed stress on the wall and 2 times of the radius of the cavity (2) If the strength parameters of the surrounding rock are Cm = 0.4MPa, m = 30°, please discuss the stability of the cavity (3) If the cavity is not stable, please calculate the radius of the plastic ring (R1) = >