Gong-kuang zidonghua (Apr 2022)
Rock burst prevention technology in multi-roadway intersection area of hard roof strong impact working face
Abstract
In order to ensure the safety of multi-roadway crossing area in the mining process of strong impact working face under hard roof, the end mining of 401111 working face of Shaanxi Binchang Hujiahe Mining Co., Ltd. is taken as the engineering background. The method of theoretical analysis and field monitoring is used to classify the rock burst hazard area of the working face during the end mining period. Moreover, the dynamic and static load influencing factors that lead to the increase of rock burst hazard are analyzed. The dynamic and static load monitoring situation during normal mining and the end mining are compared. The results show that the 401111 working face mining coal seam has strong rock burst tendency. Under the condition of hard roof, the static load is provided by the working face goaf, adjacent goaf and multi-roadway intersection area. The dynamic load is provided by the instantaneous release of elastic energy in the overlying hard roof overhanging and collapsed and multi-roadway intersection areas in the goaf. The joint action of dynamic and static loads leads to an increase in the rock burst hazard of the 401111 working face at the end of mining. And the rock burst hazard in the intersection area of the return air roadway is higher than that of the transport roadway side. The idea of separate source prevention and control of rock burst is adopted. For the overlying hard roof, the roof pre-split blasting technology is used to shorten the roof collapse step. And the dynamic load disturbance caused by the large-area overhang and collapse of the roof is reduced. For the roadway side and floor, large-diameter drilling is used to relieve pressure so as to reduce the accumulation of static load and the degree of load on the surrounding rock. At the same time, the roof of the roadway is supported by bolt+steel belt mesh and anchor cable. The side of the roadway is supported by anchor cable+steel ladder mesh so as to improve the rock burst resistance of surrounding rock. After using the rock burst prevention technology based on pressure relief and joint support, the micro-seismic events are greatly reduced. The result indicates that the coal and rock mass fracture degree is low and the integrity is good, and the safe mining of the working face is ensured.
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