开采引起的含水层失水对地表下沉的影响

为了改善矿区开采沉陷预计精度，解释华东矿区地表下沉系数大于１的原因，减小采动损害，本文基于现场钻孔水位动态观测结果，获得了覆岩破坏与含水层水位变化的３种对应关系。根据含水层失水后固相颗粒有效应力增加引起岩土体孔隙比的变化，建立了含水层失水固结沉降机理，利用叠加原理，导出了地下开采与含水层失水共同引起的地面沉降计算方法，研究实验表明，失水下沉占煤层开采下沉的２５％。

DE-WATERING EFFECT OF AQUIFER TO SURFACE SUBSIDENCE

In order to improve the predicting accuracy of mining subsidence,to explain the phenomena which the subsidence coefficient is larger than 1,and to decrease the mining damage,on the basis of bore hole measuring of dynamic water level results,the 3 kinds of relations between overburden failure and de watering of water holding strata is obtained.The void ratio may decrease with the increasing of effective stresses after water losing.The mechanism of consolidation subsidence due to de watering of water bearing strata is established.The calculation method of surface subsidence caused by underground mining and de watering is derived using superposition principle.The example demonstrates that the consolidation subsidence due to de watering accounts for 25% of the coal seam mining subsidence.