Numerical simulation of fracture propagation in freezing rocks using the extended finite element method (XFEM)

Owing to its importance to rockslides in cold regions, the evolution of heaving pressure, which acts as a driving force for fracture propagation in freezing rocks, was studied using the extended finite element method. For the growth of a fracture, the compounds of migrating water and ice lens deliver pressure from volumetric expansion as water consolidates, which is characterized by an empirical rate law. Satisfying the fracture propagation condition at the fracture tip under a given mixture volume and fracture length can result in a critical pressure level that initiated fracture growth. First, the numerical snap-through solutions of the pressure were validated against previous experimental results. The increase in pressure seemed to be limited at the freezing stage. The realistic parameters used in the empirical law for volumetric expansion rates were determined by fitting the numerical results to the experimental results. Then, parametric studies on fracture growth speeds and pressure limits were performed. The fracture size, fracture toughness of the rock, and parameters of the empirical law had a substantial effect on the variation in heaving pressure and thin fracture aperture. When fracture growth was considered, the heaving pressure tended to decrease, and the fracture propagation speed gradually reduced to zero.