浅埋采场地表裂缝-采动裂隙连通性评价及浅表水响应特征

Assessing Connectivity of Surface Clefts and Mining-Induced Fractures above Shallow Coal Seam and Water Response

西部矿区浅埋煤层开采引起地表裂缝和采动裂隙的大规模发育,二者的相互连通为浅表水体稳定及井下安全生产带来极大影响。研究以杨家村煤矿浅埋22上煤层水文地质条件为背景,通过综合实测、理论分析和反演建模等方法评估长壁工作面采动影响下的地表裂缝-采动裂隙连通性及浅表水文响应。结果表明,采高5 m、面长240 m情况下地表裂缝-采动裂隙未发生结构与水力连通,浅表含水层产生约0.77 m的水位下降;工作面长度增至300 m可使浅表含水层失稳,水位降深增大至1.33 m;水位降深与工作面长度呈正相关关系。

The extraction of shallow coal seam occurring in Western China triggers the massive propagation of surface clefts and mining-induced fractures. The connection of both can pose greats threats to shallow water stability and underground safety production. With the hydrogeology of 22 upcoal measure of Yangjiacun coal mine as the case, evaluates the connectivity of upper clefts and lower fractures induced by longwall mining and the response of shallow groundwater regime by means of comprehensive field measurements, theoretical analysis, and inverse modelling. The results show that the operation of longwall panel which is 5 m in height and 240 m in width does not result in the connection between clefts and fractures from structural and hydraulic perspectives, while inducing shallow water drawdown about 0.77 m. With panel width enlarged to 300 m, the shallow aquifer occurs to destabilization, and the drawdown also increases to 1.33 m. In general, water level drawdown witnesses a positive correlation with panel width.