THE DIFFERENCE ANALYSIS OF ROCK BURST AND COAL BURST AND KEY MECHANISMS OF DEEP ENGINEERING GEOLOGICAL HAZARDS

Rock burst and coal burst did not originally exist in nature, which were completely induced by humans'project construction such as during utilization of deep underground space and exploitation of deep mineral resources. Both of them belong to the most typical deep engineering geological hazards. For a long time, the concepts of rock burst and coal burst have been confused. This article reviewed the early research progress of rock burst and coal burst in China, and systematically analyzed the difference between them. There were fundamental differences between rock burst and coal burst in the research objects(bearing strength, energy storage and release capacity, and elastic brittleness of hard rock and coal), stress conditions(in-situ stress, disturbance stress) and boundary conditions(excavation & mining methods and procedures, disturbance range and timeliness, etc.). There were also great differences between rock burst and coal burst in the aspects of apparent phenomenon, restricted object, research object, occurrence condition, industry field, engineering construction method, engineering construction purpose, inducing mechanism, requirements and supporting principle, tendency criterion, classification type, classification grade, grade evaluation method, and so on. In conclusion, rock burst and coal burst were two kinds of parallel dynamic failure phenomena of geological body, and no subordinate relationship occurred between them. Based on the previous studies, the definition and connotation of rock burst and coal burst were given respectively. Rock burst was defined as the ejection, burst or caving phenomenon of hard rock occurring in deep buried opening(tunnel), mine roadway and pillar, accompanied by different degrees of sound. Coal burst was defined as the phenomenon that occurs in deep coal mines when coal was thrown out and releases different degrees of kinetic energy, often accompanied by vibration, loud noise, air wave or shock wave in server cases. It is suggested to replace the term "coal bump" with "coal burst" in consideration of the dynamic coal failure phenomenon and the appellative consistency. On this basis, seven viewpoints are expounded in detail in understanding the rock burst and coal burst. Finally, several key mechanisms of rock burst and coal burst were proposed from the aspects of research object, stress and boundary conditions. That is, investigations of rock burst and coal burst from the perspective of coupled static-dynamic(or dynamic-static) loading mechanics favorably agree with the full stress path of deep geological body failure, and the transformation from static state to dynamic state should be studied from the viewpoint of energy conservation. In the mechanism analysis, prediction and forecast, monitoring and early warning, regulation and control of rock burst and coal burst, the logical and dialectical relations among influencing factors should be understood scientifically.