双重上保护层叠加开采应力分布规律

为获取双重上保护层重叠采动作用下的煤层卸压规律及保护层间的相互影响,以平煤八矿一采区为原型,采用FLAC3D软件模拟了丁、戊组煤层多工作面重叠开采过程。研究结果表明,仅丁组煤层开采时,采区边界煤柱对应范围出现应力集中现象,最大应力值达到19 MPa,影响范围达到下方80 m,不利于被保护层卸压。工作面间区段煤柱最大应力值达39 MPa,但向底板传递范围较小。丁组单独开展卸压区域能够影响至己组,己组煤层应力卸压值约为1 MPa;丁组、戊组煤层重叠开采,当戊组工作面位于丁组煤层区段煤柱下方,同时丁组工作面位于戊组工作面区段煤柱上方,使丁组煤层工作面间区段煤柱应力集中减弱利于卸压,丁组煤层区段煤柱应力值由39 MPa卸载至7.5～10 MPa之间;同时当己组煤层位于戊组单独保护范围时,垂直应力卸压值为2～3 MPa,当己组煤层位于丁戊共同保护范围时,垂直应力卸压值为4～6.5 MPa。

Pressure relief law of double upper protective layer superposition mining

To obtain the law of stress redistribution of coal seam under the action of overlapping mining in multi seam working face, taking Pingmei No.8 Coal Mine No.1 mining area as the prototype, the process of overlapping mining in group D and group E coal seams was simulated using FLAC3D software. The results show that the stress concentration occurs in the corresponding range of the coal pillar at the boundary of the mining area only when the coal seam in group D is mined. The maximum stress value of the coal pillar reaches 19 MPa, and the influence range is 80 m below it. The maximum stress value of the coal pillar in the section between working faces reaches 39 MPa. The pressure relief affects J group, and the stress relief value of J Group coal seam is about 1 MPa. When the D group and E group coal seams are overlapped, and when the E group working face is located under the coal pillar of the D group coal seam section, and the D group working face is located above the coal pillar of the E group working face section, the stress concentration of the coal pillar of the D group coal seam section is weakened, and the stress value of the coal pillar of the D group coal seam section is unloaded from 39 MPa to the range of 7.5 MPa to 10 MPa. At the same time, when the coal seam of group I is located in the independent protection range of group E, the vertical stress relief value is 2 MPa to 3 MPa. When the coal seam of group I is located in the joint protection range of group E, the vertical stress relief value is from 4 MPa to 6.5 MPa.