柠条塔煤矿采煤围岩渗透性变化规律及工作面涌水量预测

Permeability changing laws of surrounding rock under the influence of coal mining and prediction of water yield of working face in Ningtiaota Coal Mine

煤矿开采围岩渗透性变化对工作面涌水量预测精度具有重要作用。本文以柠条塔煤矿顶板砂岩为研究对象,采用FLAC3D软件流固耦合模块模拟分析了围岩的水平渗透系数和垂直渗透系数变化规律,以此为基础,采用地下水模拟系统预测分析了S12003工作面的涌水量。研究结果表明:当工作面推进距离为100 m、200 m、300 m和400 m时,水平渗透系数最大分别增大约10倍、500倍、10000倍和1000000倍,垂直渗透系数最大分别增大约5倍、50倍、100倍和10000倍。对于不同的部位,其水平渗透系数和垂直渗透系数变化规律不一致。随着工作面推进距离的增加,孔隙水压力降至0 MPa的范围及覆岩上部发生塑性破坏的范围均呈现逐步增大的趋势。以此为基础,预测的工作面涌水量呈现随工作面推进先逐步增加后有所减少趋势,最终工作面涌水量基本稳定在210 m3/h左右。此时,上覆直罗组承压含水层的静储量基本已经疏干,工作面的涌水主要为含水层的侧向补给。预测结果与实际情况相符合。研究成果可为类似条件下的工作面涌水量预测提供参考。

The permeability change of surrounding rock in coal mining processing plays a crucial role in the accuracy of the prediction of water yield of working face.In this paper,taking the sandstone for roofing of Ningtiaota Coal Mine as the research object,the horizontal and vertical permeability coefficient change laws of the surrounding rock are simulated and analyzed by fluid-solid coupling module in FLAC3D software,and based on which,the water yield of working face of S12003 is predicted and analyzed by using GMS.The results show that when the advancing distance of the working face is 100 m,200 m,300 m and 400 m,the maximum horizontal permeability coefficient increased by 10 times,500 times,10000 times and 1000000 times,respectively,and the maximum vertical permeability coefficient increased by 5 times,50 times,100 times and 10000 times respectively.Different parts of the horizontal and vertical permeability coefficient change laws are not consistent.With the increase of advancing distance,the range of pore water pressure down to 0 MPa and the range of plastic damage occurs in the upper part of the overburden rock both show a gradual increasing trend.Based on this,the predicted water yield of working face show that it increases gradually and then decreases with the advances of the working face,and finally the water yield of working face is basically stabilizes at about 210 m3/h.At this time,the static storage capacity of the overlying Zhiluo group pressurized aquifer have basically been drained,and the water yield of working face is mainly the lateral recharge of the aquifer.The predicted results are consistent with the actual situation.The research results will provide reference for the prediction of water yield of working face under similar conditions.