A novel bi-modular elastic algorithm in particle Flow Code for thermal cracking modeling of rock

Abstract

Experimental studies indicated that most rocks exhibit distinct elastic moduli under compressive and tensile loading, leading to intricate stress conditions in rock mass under thermal–mechanical coupling. It is an urgent demand for advanced numerical methods that can simultaneously consider the bi-modular elasticity of rock, thermal–mechanical coupling effects, and thermal cracking behaviors to improve understanding of geological science. The Balanced Interface Method (BIM), a novel bi-modular elastic algorithm is proposed in Particle Flow Code to investigate the thermal–mechanical behavior of bi-modular elastic materials. Firstly, this study introduces the calculation principle of BIM and presents the calibration procedure for bi-modular elastic materials, which is further validated through two case exercises. Subsequently, the thermal–mechanical coupling algorithm is improved by utilizing the Flat-Joint Model (FJM), and a correction method for the position of the compression-tension interface based on BIM for the thermal–mechanical coupling process is introduced, which is then verified by a comprehensive transient heat conduction case with different elastic assumptions. Lastly, a cracking example induced by thermal–mechanical coupling is simulated. The numerical results demonstrate consistency with previous studies and reveal a significant improvement in the thermal cracking behavior of rock, proving the developed algorithm’s necessity in investigating the coupled thermal–mechanical problem.