Question:
Consider an underground limestone mine in flat strata where pillars are 29 m high and depth is 258 m. Rock properties are: E = 77.9GPa, v = 0.20, Co = 148 MPa, To = 11.6 MPa, unit weight = 24.7kN/m3. A joint set of variable dip pervades the mine. Mohr-Coulomb properties are: c = 4.34 MPa, f = 40?. Pillars must have a safety factor of 2.5 with respect to any potential failure mechanism. Is this possible? Show why or why not.