Research review of the state key research development program of China:Deep rock mechanics and mining theory

With the gradual depletion of mineral resources in the shallow earth,the exploitation of deep mineral re- sources has become normal. However,due to the true nature of the typical “three highs” occurrence environment of the deep rock mass and the additional attributes of “strong disturbance” and “ strong aging” of resource exploitation,the large-scale engineering disasters with deep high-energy frequently occur,and the mechanism is unclear. It is difficult to effectively predict and control those engineering disasters. The traditional rock mechanics and mining theory are contro- versial in terms of deep mining applicability. In this paper,the research developments of the project called Deep Rock Mechanics and Mining Theory within the framework of the State Key Research and Development Project are reviewed, including ① The technical system of in-situ coring,transportation and testing with in-situ physical state has been pre- liminarily formed,and the in-situ restoring rock mechanics tests at different depths have been carried out. ② The long- term in-situ mechanical behavior of rock mass with different depths under disturbance is systematically explored,and the dynamic constitutive models of rock under various stress environments are constructed. ③ The relationship between average stress and deformation modulus of deep non-linear rock mass under complex geological conditions is proposed, and the batch data processing network (GMDH) algorithm is developed to inverse the deep geostress field. The energy accumulation and dissipation characteristics in the process of rock failure are systematically studied. ④ The criteria for assessing the characteristics of “ strong disturbance” and “ strong timeliness” are put forward. The damage evolution and discontinuous abutment pressure theory of coal under the path of strong disturbance stress in deep mining are ex- plored. The damage and fracture,energy evolution and permeability characteristics of coal under strong disturbance in deep mining are studied. ⑤ The three-dimensional visualization model of complex pore structure in rock mass is estab- lished,and the visualization of stress field in the process of dynamic crack propagation is realized. The freezing experi- mental device of the three-dimensional stress field of the visualized physical model is developed. ⑥ The experimental simulation of slab crack failure in the surrounding rock of deep hard rock rectangular tunnel is carried out,and the the- ory of stably releasing stress in deep near stope area are put forward. The method and technology of fine rock breaking coupled with high stress and blasting in deep hard rock are developed and applied. ⑦ The evolution mechanism of fracture initiation and differentiation of three disaster modes under a strong unloading of deep hard rock is summa- rized,and a new method of continuous-discontinuous calculation based on material point principle is proposed,which innovates the method of cracking-restraint support for chamber stability. ⑧ The main influencing factors of safe green mining of deep coal are analyzed,and a new safe green mining mode of “high protection and low loss” is preliminarily constructed. ⑨ The spatial model of deep mining and the dy-namic optimization model of production plan are estab- lished. The unloading technology of deep excavation face,the integrated pressure relief control strategy of deep high stress pillar and the stress isolation technology of deep pressure relief curtain are put forward. Based on those contents, a theoretical research system for deep rock me-chanics and mining theory was initially constructed,which will provide theoretical basis and technical support for the development of deep mineral resources in China in the future.