The influence of stress anisotropy and stress shadow on frost cracking in rock

Abstract

With growing research interest of liquefied natural gas storage in underground frozen host rock cavern, it is the key to have a comprehensive understanding of rock deformation and cracking under freezing and their impact on the stability of the underground storage caverns. In this work, a coupled thermo-hydro-mechanical model is developed in the framework of TOUGH-FEMM simulator to gain such understanding, where complex coupled processes involving water–ice phase transition as well as non-planar frost cracks are rigorously considered. In this model with the TOUGH-FEMM, heat transfer and fluid flow under freezing are simulated using TOUGH2, while mechanical deformation and cracking are simulated using the hybrid finite element-meshfree method (FEMM). The new modelling component for simulating temperature transfer and freezing-induced strain is validated against data from a previous laboratory experiment on sandstone by Neaupane et al. Finally, the influence of stress anisotropy and stress shadow on frost cracking are discussed using a set of experiments and TOUGH-FEMM modelling. The experimental and numerical results show that frost-induced cracks propagate towards to the direction of the maximum principal stress, while the stress shadow between multiple cracks has a significant impact on the damage pattern.