Study On Mechanism Of Fault Activation Induced Coal And Gas Outburst Under The Influence Of Mining

The research mainly concentrated in the gas occurrence characteristics within the fault zone, and its study on the impact of coal and gas outburst under static or quasi-static, rather than most of the fault zone with the coal and gas outburst is occurred in the process of mining, tunneling and blasting, induced by stress disturbance, lack of research on mining under the influence of fault activation induced outstanding. Therefore, in order to ensure coal mine safety production, further study of mining under the influence from fault activation induced mechanism is imperative.This papers take coal and gas outburst phenomena in the fault zone as the main research object, based on the combination hypothesis, adopting the combination of theoretical analysis, numerical simulation method, systematic study on the mining under the condition of disturbance, fault activation induced the process of coal and gas outburst fault activation patterns, fault and the related stress distribution and deformation and failure characteristics of coal seam, the gas migration dynamic characteristics and dynamic process of coal and gas outburst, and then reveals the mining disturbance, fault activation, causal relationship between the coal and gas outburst, determine a mechanism of the mining under the influence from fault activation induced coal and gas outburst. Based on the analysis of ground stress, gas pressure, fault and so on various influence factors in mining under the influence of fault activation induced coal and gas outburst, mainly got the following useful conclusions:(1) Under the influence of mining, fault activation induced coal and gas outburst process can be divided into 4 parts, stress concentration stage, fault activation induced by coal and rock burst phase, gas pressure driven crack extension stage and phase of coal and gas outburst occurred, ground stress, gas pressure, fault at various stages play a respective role.(2) Under the action of mining disturbance, within the fault zone, the in-situ stress state is the main controlling factors of coal and gas outburst, the occurrence of coal and gas outburst to provide main power, large fault tectonic stress is the decisive factor of high ground stress, under the condition of high pressure gas, and mining disturbance caused by the fault activation, trigger a major cause of coal and gas outburst occurred, and the damage form of fault activation induced is closely related to the face of the ground stress state; gas pressure is the main factor in the process of coal and gas outburst occurred, but the existence of high ground stress determines the gas pressure.(3) Risk coal and gas outburst is closely related to the fault structure, due to the complexity of the effect of in-situ stress and stress field, in the same fault structural feature, the stress concentration degree is different, it controls the gas migration and enrichment of relatively, it is easier to reach the boundary conditions of coal and gas outburst factors.Based on the theory of double porosity physical model of coal, the fault zone with considering the influences of mining gas migration mechanism research, established the mathematical model considering the effects of mining coal seam gas migration, and studied the rule of change under the mining effect, the gas pressure gradient within the fault zone; based on the theory of masonry beam, studied the fault activation mechanism, systematic analyzed the damage mechanism under the influence of mining coal in the fault zone. Research shows that: the evolution of the ground stress, control of coal seam gas occurrence and migration, it plays a leading role; working face by the footwall fault advancing, prone to activate phenomenon, fault and working face by fault on the plate to push fault after fault, fault is easy to activate even slip.In this paper, through the gas coal and rock failure process analysis system RFPA2D-Gasflow, on the basis of considering the heterogeneity of rock material microscopic structure, carried out the research on fault activation induced coal and gas outburst under the influence of mining, achieved a beneficial research, impact on the fault zone of coal and gas outburst prevention and monitoring is of important theoretical value.