含断层构造采动底板岩体突水过程数值模拟

Numerical Simulation on the Process of Water Inrush from Mining Floor with Fault Structure

为确保承压水上煤层安全开采,从"下三带"理论入手,以实际工程为背景,基于FLAC3D数值软件,构建断层构造承压水上煤层开采模型,分析断层影响下底板破坏规律及突水路径,结果表明:随着工作面推进,在距断层一定范围内,煤层底板最大破坏深度为10 m,靠近断层时,受断层影响,煤壁前下方破坏深度增大至16m,并与断层破坏带导通形成突水通道;受采动影响,孔隙水压力沿着底板隔水层和断层均发生明显导升,其高度约6~8m不等,且流水矢量方向与底板突水通道路径一致;含30°、45°和60°断层工作面开采突水通道形成时,对应剩余临界水平煤柱长度分别为67m、37m和18 m,说明断层倾角越小,需要留设的保护煤柱越长,即在相同推进距离下,断层倾角越大越不易发生底板突水现象。该研究结果为矿井煤柱留设提供了科学依据,具有重要的实用价值。

In order to ensure safe mining of coal seam above confined water, the FLAC^3D was used to establish a mining model of fault-structure coal seam above confined water, which was based on the analysis of three failure zones in the floor and took the actual project as the background. Then, the failure law and water inrush path of the floor under the influence of fault were ana lyzed. The results were concluded as follows. Firstly, the maximum failure depth of coal seam floor was 10 m when the working face was advancing to a certain distance from the fault. Affected by the fault, the failure depth of the inclined floor rock be- low the coal wall increased to 16 m when the working face was close to the fault. And, the failure zone of the floor was connected with the fault zone to form a water inrush channel. Secondly, the pore pressure water was obviously rising along the waterresisting layer and fault, and the ascending height was about 6-8 m. The vector direction of the flow was consistent with that of the water inrush channel of the floor. Thirdly, when the water inrush channels in mining face with 30°, 45° and 60° faults were formed, the remaining lengths of the critical horizontal coal pillar were 67 m, 37 m and 18 m respectively. It indicated that the smaller the dip angle was, the longer distance the protective coal pillar should be reserved. That was, under the same advancing distance, the greater the fault dip, the less prone to floor water inrush. The results of the research could provide a certain scientific basis for the coal pillar setting, and had important practical value.