Simulation of buoyancy-driven fracture propagation using the displacement discontinuity boundary element method

摘要

A coupled flow and fracture propagation model is described for the simulation of buoyancy-driven propagation of volcanic dyke structures. The fluid properties are assumed to be Newtonian and the elastic interaction between the opening volume of the crack structure and the surrounding rock is evaluated using displacement discontinuity boundary element influence functions. The shape of the evolving crack is represented by unstructured triangular elements with a region of moving elements at the crack edge. A refinement of this approach is described to allow differential renewal of the edge region, depending on the incremental propagation distance. This approach is compared to a simpler computation strategy using regular fixed grid elements with no specific control of the asymptotic crack edge opening shape. Some illustrative examples are provided to indicate the large-scale footprint shape of a dyke structure and the effect of source flow duration.