深部采煤覆岩移动和地表沉降研究

Study on Overlying Strata Movement and Ground Subsidence in Deep Coal Mining

为揭示深部采煤覆岩移动和地表沉降规律,以兖矿集团东滩煤矿6采区63_(上)04、63_(上)05、63_(上)06工作面采矿条件为背景,基于微震及地表沉降监测数据,利用UDEC对深部采煤覆岩移动和地表沉降进行了数值模拟研究。结果表明:(1)沿工作面回采方向(z_(1)方向)的模拟结果显示,随着工作面开采宽度的增加,覆岩的破坏形式由大块整体垮落转变为覆岩大变形;大能量矿震逐渐减少,能量趋于平稳;导水裂隙带高度先迅速升高后基本不变,稳定在85 m,与经验公式计算相符,据此确定了覆岩的三带分布;工作面回采完毕后,在采空区上方形成三角拉应力带,采空区边缘20~30 cm处形成了竖向峰值应力为50 MPa的超前支撑压力带。(2)垂直工作面回采方向(z_(2)方向)的模拟结果显示,紧邻采空区的存在、采空区间煤柱的破坏一定程度导致63_(上)06工作面回采后覆岩竖向位移迅速增大,并波及地表。(3)将模拟得到的地表沉降数据和实测数据绘制成地表沉降曲线图,地表沉降曲线呈“U”字形,且在煤层回采过程中,沉降速率逐渐增大;通过将模拟数据与现场实测数据进行对比,其平均误差仅为8%,说明模拟结果真实可靠,可为同类煤矿地表沉降预测提供借鉴。

In order to reveal the law of overlying strata movement and surface subsidence in deep coal mining,with the mining conditions of working faces 63_(upper)04,63_(upper)05,and 63_(upper)06 of No.6 mining area in Dongtan Coal Mine of Yankuang Group as the background,we carried out a numerical simulation study of surface subsidence in deep coal mining and overlying strata movement with UDEC based on microseismic monitoring and surface subsidence data.The results are as follows:(1)According to the simulation results along the mining direction(z_(1))of the working face,as the mining width of the working face increased,the damage form of the overlying rock changed from a large overall collapse to a large deformation of the overlying rock;the large-energy mine earthquake gradually decreased and the energy became stabilized;the height of the water-conducting fissure zone increased rapidly and then remained basically unchanged at 85 m,which was consistent with the empirical formula calculation.Based on this,the three-zone distribution of the overlying strata was determined;after the mining of the working face was completed,a triangular pull-out was formed above the mined-out area.In the stress zone,an advanced support pressure zone with a vertical peak stress of 50 MPa was formed at the edge of the goaf at 20~30 cm.(2)According to the simulation results of the stoping direction(z_(2))of the vertical working face,it can be seen that the existence of the adjacent mined-out area and the destruction of the coal pillars in the mined-out interval to a certain extent led to the rapid increase of the vertical displacement of the overlying strata and its subsequent spreading to the surface after working face 63_(upper)06 was mined.(3)The surface subsidence data obtained by the simulation and the measured data were drawn into a graph.The curve is U-shaped,and the subsidence rate gradually increases during the coal seam mining process.The comparison between the simulated data and the measured data on the spot indicates that the average error is only 8%,and the simulation results are true and reliable,which can provide reference for the prediction of surface subsidence in similar coal mines in the future.