Study on the block-caving criterion of rheologic fracture of jointed rockmass under inducing condition

The jointed rock-mass for the reheloogic fracture criterion under the inducing condition is a key to the success of the natural caving. And the rheologic fracture of jointed rock mass under induced condition was studied in this paper. Three kinds of different failure mechanisms of jointed rock mass for the rheologic fracture were induced. And a uniform failure criteria based on these failure mechanisms was obtained, which was judged according to the length of wing crack in the jointed rock mass. In this foundation, three necessary conditions such as the failure condition, the free face condition and the equilibrium condition were proposed firstly for the jointed rock mass to block caving under the action of gravity. And the criterion mathematical expression of rheologic fracture and block caving of the rock mass was deduced and established. Finally, the research results had been transformed to the computer program, which can provide a new and effectual way for us to study and predict the rule of block caving of rheologic fracture ore-rock.