Applications of Hydro-Mechanical Phase-Field Model: From Laboratory Scale to Natural Fracture Networks

In recent years, the hydro-mechanical phase-field method has demonstrated its value in studying the geotechnical properties of rock mass. This paper presents a hydro-mechanical phase-field model that couples a length scale insensitive phase-field fracture theory and Biot’s theory in poroelastic media. The proposed model exhibits the capability to simulate complex crack behavior, including non-planar propagation and crack coalescence, as well as accurately capturing the pressure drop when induced cracks merge with pre-existing cracks, which indicated the process of fluid filling the pre-existing cracks. Two numerical examples demonstrate the model's ability to simulate hydraulically induced fractures in geological materials across multiple scales and provide insights into fracture behavior. In fracture networks injection, the majority of the time is spent in the process of the dropped pressure gradually increasing to trigger the next fracture event. The proposed model provides an effective tool for investigating fracturing from laboratory-scale to field-scale and has promising application prospects in studying hydro-mechanical fracture behavior in geological materials.