Formation Process Of Coal Measure Reverse Fault And Its Influence On Mining Disaster

Faults are produced and developed in the tectonic movement of the earth's crust.As a widely existing structural form in coal measure strata,there are structural stress and residual energy in the surrounding rock mass after the formation of faults.Under the influence of mining disturbance in working face,many kinds of mine disasters may be induced,which poses a great threat to the safety of underground workers and is not conducive to the sustainable development of coal mine economy.Therefore,it is particularly important to study the influence of fault formation process on mining disasters.In this paper,based on the mechanical mechanism of fault formation,the physical simulation test is carried out by using the self-developed experimental system.Combined with the numerical simulation method,the formation process of reverse fault and its influence on mining disaster are studied.The main research results are as follows:Based on the mechanism of inverse fault formation geomechanics,a coal-bearing reverse fault formation simulation experiment system RF-2 with stable structure,high automation,and good sealing performance was designed and developed,providing a new experimental platform for related research on coal-bearing faults.Using this system for physical simulation experiments,the formation process of reverse faults was reproduced.The formation process of reverse fault is analyzed by physical simulation and numerical simulation.The results show that the formation process of reverse fault can be divided into four main stages according to the movement and deformation characteristics of rock stratum.During the formation process of reverse fault,the displacement of upper wall rock stratum is larger,while that of lower wall rock stratum is basically unchanged,the horizontal displacement is decreasing from left to right,and the vertical displacement is from bottom to top In the process of formation,the horizontal stress in the rock layer increases first and then decreases,and the variation range of the hanging wall is larger than that of the footwall,while the variation of the vertical stress is smaller,and the vertical stress in the footwall increases,while the vertical stress in the hanging wall increases first and then decreases,and finally rebounds;after the development of the reverse fault stops,there is still a higher level in the rock layer and at the fault Residual structural stress.Mining experiments based on the formation process of reverse faults and mining experiments of prefabricated faults were carried out.The response characteristics of mining rock formations in the two cases were compared and analyzed.The results show that the rock movement failure rules of the two experiments are roughly the same,but the rock formations after the formation of reverse faults There is tectonic stress inside.In the process of coal mining,the interaction between mining stress and structural stress results in more violent overburden movement,higher caving zone height and greater rock fragmentation.In terms of stress changes,the vertical and horizontal stress changes of the roof of the two experiments are roughly the same,both of which show that the stress of the rock layer near the mined-out area increases first and then decreases,but the magnitude of the stress change of the mining test roof after the formation of the fault also changes.Significantly larger than prefabricated fault mining experiments.The decrease is mainly due to the pressure reduction caused by the mining of the lower coal seam.The upper rock layer,which is far away from the working face,has a small effect on the change in stress due to mining.The root cause of mining-induced disasters under the influence of faults is mainly the tectonic stress field generated during the formation of reverse faults.When mining engineering is carried out near the fault area,the superposition of tectonic stress and mining stress causes the regional rock formation to respond more violently and easily.A variety of mine disasters have been induced,so this article proposes related preventive measures for the disaster,including:protection of coal pillars for fault protection,blasting pressure relief in stress concentration areas of fault planes,grouting reinforcement for fault fracture zones,and support technology for broken surrounding rock roadways in fault zones.