极薄煤层跨采下伏大巷变形破坏规律研究

针对极薄煤层跨采下伏大巷变形破坏问题,采用地质雷达测定巷道松动圈和三维激光扫描仪监测巷道变形的研究方法,研究了大巷跨采条件下的松动圈大小及巷道变形规律。监测结果表明:大巷的剧烈变形并未发生在相应的工作面周围,而是落后工作面数十米的位置,其变形形式为巷道底板整体上鼓,最高达到287.4 mm;巷道两肩及巷顶未发生明显下沉破坏。大巷破坏原因为:受采动影响,大巷上覆岩层破坏导致大巷上部工作面采空区积水沿裂隙流入大巷周围,大巷围岩受水浸泡变软膨胀,同时,上部工作面的开挖使得巷道垂直方向应力获得释放,导致大巷底板向上抬升。鉴于跨采影响下导致巷道变形较大,对于类似情况建议将U型钢可伸缩支架的排距从1 m减小为0.8 m。

Deformation and failure rules of underlying roadway of cross mining in ultra-thinness coal seam

Aiming at the problem of deformation and destruction of the overlying roadway of overhead-mining in very thin seam,the research methods of measuring the roadway loosening circle and 3 D laser scanner to monitor the deformation of the roadway using geological radar are studied. The monitoring results show that the severe deformation of the roadway does not occur around the corresponding working face, but is located in tens of meters behind the working face. Its deformation form is the overall floor heave, up to 287.4 mm;no obvious subsidence failure occurred on both shoulders and roof of roadway. The cause of the damage to the roadway is: due to the impact of mining, the damage of the overlying rock layer on the roadway causes the water in the goaf of the upper working face of the roadway to flow into the surrounding of the roadway along the cracks, and the excavation of the surface allows the stress in the vertical direction of the roadway to be released, causing the floor of the roadway to rise upward. In view of the large deformation of the roadway under the influence of cross mining, it is recommended to reduce the row spacing of the U-shaped steel telescopic support from 1 m to 0.8 m for similar situations.