Research progress and prospect of deep rock mechanics based on coupled static dynamic loading testing

Deep surrounding rocks are highly statically stressed before mining (excavating) and will inevitably experience disturbances from unloading,mining,stress adjustment or their combinations during mechanical or blasting excavation,which actually suffer from a typical coupled static dynamic stress.Studying deep rock behaviors from the perspective of coupled static dynamic mechanics is more accordant with the practical stress conditions of deep surrounding rocks.In view of this,the concept of “coupled static dynamic rock mechanics” and the history of experimental research on coupled static dynamic rock mechanics from one to two dimensional state and then to three dimensional state are presented,focusing on the development and advances in the development of the true triaxial coupled static dynamic rock mechanics test system.Based on an in depth and scientific understanding of deep rock mechanics,the mechanical response,failure characteristics and energy laws of deep rocks under various coupled static dynamic stress states are revealed,and some abnormal rock failure phenomena such as rockburst and spalling are reproduced and their occurrence mechanisms are revealed in accordance with the related experimental results.On this basis,the common characteristics of the true triaxial coupled static dynamic rock mechanics testing machines are summarized systematically.Four development directions of future research are also proposed:① Developing the true triaxial SHPB coupled dynamic and static loading testing machine that can realize the function of “three dimensional high static stress+unloading+impact disturbance”;② Developing a large scale rock internal unloading true triaxial testing machine;③ Focusing on the energy mechanism of rock burst in deep surrounding rock three dimensional coupled dynamic and static loading rock mechanics tests;and ④ Carrying out threedimensional coupled dynamic and static loading rock mechanics tests based on deep in situ coring technology.