上行开采条件下多煤层开采覆岩破坏规律研究

摘要

In order to quantatively study the failure rule of the overlying rock strata under the condition of the ascending mining of the single seam and multiple seams, FLAC3D numerical simulation sofware was used for studying the failure rule of the overlying rock strata in two cases in Maiduoshan Mine, that is, the first case is that only No. 6 seam is mined, and the second case is that the No. 5 seam is first mined and then No. 2 seam. Study results showed that in the first case, the sagging subsidence zone mainly developed 491. 02 m below the surface, the development height of the water flowing fractured zone was 51. 70 m and the surface subsidence amount was 94. 00 mm;in the second case, the sagging subsidence zone mainly developed 380. 00 m below the surface, the development height of the water flowing fractured zone of No. 6 seam was 59. 00 m and the surface subsidence amount was 375. 00 mm. The impact of the ascending mining on the develoment height of the water flowing fractured zone of the lower No. 6 seam was not big, the development of water flowing fractured zone of the upper No. 2 seam led to the scope of the sagging subsidence zone to be reduced, and the the surface subsidence amount was significantly increased due to the mining of the upper No. 2 seam.%为了定量研究上行开采条件下单一煤层和多煤层开采的覆岩破坏规律,利用FLAC3D数值模拟软件,分别对麦垛山煤矿仅开采6煤和先开采6煤后开采2煤两种情况下覆岩破坏规律进行了研究,结果表明:仅开采6煤时,弯曲下沉带主要发育在地表以下491.02 m,导水裂缝带发育高度为51.70 m,地表下沉值为94.00 mm;先开采6煤后开采2煤时,弯曲下沉带主要发育在地表以下380.00 m,6煤导水裂缝带发育高度为59.00 m,地表下沉值为375.00 mm.上行开采对于下部煤层6煤导水裂缝带发育高度影响不大,由于上部煤层2煤导水裂缝带的发育,导致弯曲下沉带范围缩小,地表下沉值由于上部煤层2煤的开采而显著增大.