关键词: 静力定向破岩, 膨胀压力, 裂纹扩展, 巷道悬顶

Abstract: The problem that the roof of the curved triangular area at the end of the mining face is too long, Threats to the safe and efficient production of the mining face, At present, the problem of roof hanging is mainly solved by means of pre-cracking blasting. Due to the ban of pyrotechnics in the goaf of high gas mines, the use of this method is limited. Based on this problem, the static-oriented rock breaking technology is developed to solve the problem of excessive roof hanging of coal mine head roadway. Through the static fracture agent expansion mechanical properties test, the factors affecting the expansion pressure of the crushing agent are analyzed. Based on the test results, the expansion pressure of the static breaker is mainly affected by the water-cement ratio of the slurry and the borehole diameter, and the expansion pressure of the slurry will gradually increase as the ratio of the water-cement ratio of the slurry decreases and the pore diameter increases. Taking into account the fluidity of the slurry, it is determined that the optimum water-cement ratio of the static crusher in industrial applications should be controlled between 0.2 and 0.35. Based on the elastic mechanics and rock mechanics analysis of the cracking principle of rock under porous pressure, the principal stress surface between the boreholes is the axial plane between the holes, the expansion of the unit crack is related to the magnitude of the expansion pressure, and the point is related to the position of the hole core.. Relatedly, increasing the aperture or reducing the hole pitch can effectively promote the crack propagation; According to the specific engineering geological conditions, combined with the static crusher expansion mechanics test and the analysis results of the rock cracking principle under porous pressure, the concrete design of the construction scheme is carried out, The specific operation methods and steps of using the principle of “three tubes, two inputs and one return” during static grouting construction are discussed. The field application results show that after applying the static rock breaking technology to solve the suspended roof problem of the end roadway, the length of the suspended roof of the end roadway is reduced by 36%, and the effect is significant to ensure the safe and efficient production of the mining face.