厚覆盖层矿山地下开采地表塌陷机制分析

随着矿山开采深度的不断增加,厚覆盖层成为部分深部地下矿山的主要特点。以物探调查、变形监测以及理论分析为手段,对某典型厚覆盖层金属矿山地下开采初期地表塌陷的成因与机制进行了分析。结果表明,厚覆盖层中存在的大面积采空区为地表塌陷变形提供了空间,采空区顶板厚度较小为地面塌陷的发展提供了条件,采空区的存在是地表塌陷的主要原因。地表出现塌陷以后,塌陷范围以塌坑为中心继续向外扩展,受覆盖层内采空区走向,断层和岩层分界面等地质缺陷影响,塌坑向西、向南与向北三个方向上的扩展较向东快得多。降雨会增大塌坑向外扩展的速度,因为地表水的下渗加快了塌坑周围岩土体向塌坑方向的移动和下沉。

Analysis of mechanism of surface subsidence caused by underground mining with thick overburden

With the increasing of mining depth, thick overburden becomes the main feature of deep underground mines. By geophysical surveys, deformation monitoring, as well as the theoretical analysis, mechanism of surface subsidence caused by underground mining in a typical thick overburden metal mine was analyzed. The results obtained show that goaf in thick overburden provides space for ground subsidence; and smaller thickness of the gob creates condition for the development of ground subsidence, which is the main reason for surface subsidence. After surface subsidence occurred, centering on collapse pit, the range of subsidence continues to expand outward. Because of the strike of goaf and geological defects, such as faults and rock interfaces, collapse pit expands faster in the north, west and south than in the east. Rainfall will increase the expansion speed of the collapse pits, because the infiltration of surface water accelerated the movement and subsidence of the surrounding rock and soil toward the pit.