Extended finite element modelling of fracture propagation during in-situ rock mass alteration

This paper investigates the e ect of rock mass alteration on the initiation and propagation of fractures. Mining-induced fractures influence the stability of overburden and may provide pathways for mass transfer in underground environments. However, the usefulness of existing fracture modeling techniques with discrete element methods and traditional finite element approaches is strongly hindered by pre-defined joints and re-meshing, respectively. In this paper, we use the Extended Finite Element Method/Modelling (XFEM), which makes the initiation and propagation of a fracture totally along a solution dependent path without the need for mesh refinement. The model is constructed based on the conditions of a previously published case study, located in Western Turkey. The results show that the roof strata fracture propagation occurs in four stages, namely initiation stage, steady growth stage, sharp increment stage, and stabilization stage. The “arch-shaped” fracture propagation curve obtained from this simulation shows a good agreement with both laboratory tests and discrete element numerical simulations. Moreover, the actual height of the fractured zone is predicted accurately in accordance with a previous empirical study. The current paper shows that XFEM is suitable to describe the fracture propagation during longwall mining.