Novel numerical approach to jointed rock mass simulation: element partition method

In the finite element method,the tri-node triangular element exhibits a geometrical characteristic,that is,when a fracture runs through it,one node is always located at one side of the fracture and another two nodes located at the other side.The former node can potentially construct two contact pairs with the latter two nodes.Through the two contact pairs is the stiffness matrix of the partitioned element derived to represent the contact and friction effect between interfaces of joint or fracture.Based on the advantage of this geometrical characteristic of triangular element,an element partition method(EPM) is developed to simulate the joint or fracture propagation of jointed rock mass.Due to the fact that the stiffness matrix of the partitioned element shares the common nodes of the corresponding intact triangular element,it doesn’t need to modify the original mesh configuration for setting up the joint element.The fracture propagates in the manner of successive element partition.To represent the newly generated and pre-existing fractures,it is just to displace the stiffness matrix of original intact triangular element with that of the partitioned element.This makes the simulation of the fracture propagation highly convenient and efficient.However,the present method is only an approximate method for the elastic-plastic deformation of the two bodies generated by the element partition.By simulating an experiment of fracture propagation and coalescence,good agreement is found between the experimental and the simulated results,which suggests that the present method is validated and feasible.