Time-dependent crack propagation in a poroelastic medium using a fully coupled hydromechanical displacement discontinuity method

Many problems in subsurface rocks which are naturally filled with saturated cracks and pores (with one or more fluid phases) are better understood in a poroelastic framework. Displacement discontinuity method ( DDM ) is particularly ideal for problems involving fractures and discontinuities. However, the DDM in its original form is limited to elastic problems. The paper derives fundamental solutions of a poroelastic DDM . Then introduces a numerical formulation and implementation for the poroelastic DDM in a code named constant element poroelastic DDM ( CEP-DDM ). The accuracy and validity of the proposed solution and the newly developed code is verified by an analytical solution at short-time and long-time. Numerical results showed good agreement with analytical results at short time (undrained response) and long time ( t = 8000 s) (drained response). A crack propagation scheme for crack propagation problems is introduced and demonstrated in an example which enables the code to follow crack propagation in time and space.