Research review of rock mechanics experiment and numerical simulation under THMC multi-field coupling

The study of multi-field coupling of rocks is currently a pressing and difficult problem at present. To better analyze the interaction mechanism of rocks under of multi-field coupling, research is mainly carried out by experiment and numerical simulation. On the basis of summarizing the research and development of multi-field coupling micro-meso-macro multi-scale mechanical test equipment at home and abroad, and the developments of numerical simulation software and coupling calculation program, the development direction of rock mechanical test equipment and numerical analysis under multi field and multi-phase coupling are prospected. To study the mechanical properties of rocks under multi-field coupling, a multi-field coupling test system with different physical fields was designed by improvement through research and development. Based on the development of the test equipment, modern non-destructive detection methods, such as real-time computed tomography (CT) scanning technology, scanning electron microscopy (SEM), nuclear magnetic resonance imaging (NMRI), X-ray stereo imaging and ultrasonography, were developed. Acoustic wave technology can not only nondestructively detect the micro-structure and evolution process of rock internal pores, but also clarify the macro-relationship of rock physical fields in the multi-field coupling action of thermal-hydrological-mechanical-chemical (THMC), and further clarify the rock performance under multi-field coupling action from the perspective of a combination of micro and macro scales. With the advancement of computer technology, the development of numerical simulation software and coupling calculation program under multi-field coupling of rock has made certain progress. Especially, the development of the numerical simulation software of THMC four-field coupling interaction combined with TOUGHREACT and FLAC3D, and the multi-field coupling calculation program of Comsol docking with MATLAB provide technical supports for the development of multi-field coupling simulation of rocks. Finally, the key difficulties and future research directions of rock multi-field coupling research were discussed and analyzed, which can provide a reference for engineering practice and related problems.