爆破荷载下瓦斯抽采钻孔致裂增透作用机理研究

Study on Mechanism of Increased Permeability by Gas Drainage Drilling Fracturing Under Blasting Load

为改善高瓦斯低透气煤层透气性差的问题,本文通过数值模拟、实验室试验相结合的方法研究穿层爆破中瓦斯抽采钻孔对煤岩体致裂增透的作用机理。运用数值模拟软件ANSYS对爆炸荷载作用下瓦斯抽采钻孔的裂隙扩展机理进行数值模拟,再通过在实验室构建瓦斯抽采钻孔穿层煤层的相似模型,进行煤层爆破致裂增透试验。试验结果发现:煤层底板岩层破坏比较严重,裂缝发育长,岩层表面产生贯通裂纹,爆破孔和瓦斯抽采钻孔之间裂纹贯通,爆破孔产生的裂隙向抽采孔方向扩展,试验结果与数值模拟结果相吻合。爆破结果说明,瓦斯抽采钻孔可以有效增加煤层的裂隙,提高煤层的增透,改善煤层的透气性问题。

In order to solve the problem of the poor gas permeability in high-gas and low-permeability coal seams,in this paper,the numerical simulation and the laboratory test were used to study the mechanism of increased permeability by the gas drainage drilling fracturing to coal and rock mass under the cross-layer blasting.The numerical simulation software ANSYS was used to numerically simulate the crack propagation mechanism by the gas drainage drilling fracturing under the action of the blasting load.A similar model for the cross-layer coal seam with gas drainage drilling was built in the laboratory to carry out the increased permeability experiment under coal seam blasting.The test results show that the floor rock of the coal seam is severely damaged,the fractures are long,the surface of the rock occurs through-fractures,the fractures around the blasting hole and the fractures around the gas drainage hole are connected,and the fractures generated by the blasting hole expand in the direction of the drainage hole.The test results and the simulation results are consistent.The blasting results show that the gas drainage drilling can effectively increase the fractures of the coal seam,improve the permeability of the coal seam,and improve the permeability of the coal seam.