人工湖下连采连充煤炭开采地表移动变形预测研究

Predicting surface movement and deformation for continuous mining and continuous backfilling under an artificial lake

为研究人工湖下煤炭连采连充开采后的地表移动变形规律,对连采连充工作面进行了室内力学试验和现场取芯力学试验,验证充填体的可行性;基于等价采高概率积分法,对连采连充工作面进行地表沉陷预测;通过数值模拟计算,分析导水裂缝带发育高度,并与概率积分法结果进行对比。结果表明:充填体的强度5.063 MPa超过设计强度2.0 MPa,能够确保矿井的安全开采;连采连充工作面开采后,地表倾斜值极值0.3 mm/m,地表水平变形极值-0.2 mm/m,小于砖混结构建筑I级损坏范围,周围地表沉陷平缓,无安全隐患;导水裂缝带发育高度约49.7 m,距离隔水层约160.3 m,水下采煤安全,FLAC^(3D)数值模拟和概率积分法结果比较接近,验证连采连充技术可有效减缓地表移动变形。

To investigate surface movement and deformation characteristics due to continuous mining and continuous backfilling(CMCB)of coal under artificial lakes,laboratory and field coring mechanical tests were conducted on the CMCB area to verify the feasibility of the filling body.Based on the equivalent mining height probability integration method,the surface subsidence of the CMCB area was predicted.The height of the water-conducting fracture zone was analyzed using numerical simulation,and its results were compared with those of the probability integration method.The results show that the strength of the filling body is 5.063 MPa,which is higher than the designed strength of 2.0 MPa,ensuring safe mining.Owing to continuous mining and backfilling in the area,the maximum inclination value of the surface was 0.3 mm/m and the maximum horizontal deformation value of the surface was-0.2 mm/m,respectively,which is less than the range of gradeⅠdamage to brick and concrete structures.The surrounding surface subsidence was gentle,and there was no safety hazard.The height of the water-conducting fracture zone was about 49.7 m,and the distance from the waterproof layer was about 160.3 m,indicating the safety of underwater coal mining.Results of the FLAC^(3D)numerical simulation and probability integration method were close,thereby verifying that the CMCB technology can effectively slow down surface movement and deformation.