充填开采隔水关键层渗流稳定性力学模型及分析

Mechanical model and analysis of seepage stability in key aquiclude strata during backfill mining

分析充填体与隔水关键层耦合作用关系,建立了充填开采隔水关键层非线性渗流稳定性力学分析模型,给出了充填开采隔水关键层非线性渗流失稳判据,研究了隔水关键层非线性渗流失稳与临界充实率的定量关系。研究结果表明:充填采空区垮裂带岩体渗透性具有明显的横向分区与垂直分带特征,其渗透性沿横向由煤壁侧向采空区中部逐渐减小,并趋于定值,沿纵向由下至上呈对数型逐渐衰减变化规律。现场实测结果表明:充填开采后裂隙损伤发育至复合隔水关键层下部岩层,电阻率监测值为40~50Ω·m左右,工作面未发生水渗流涌水现象,隔水关键层的控制效果较好,实现了含水层下煤炭资源的安全开采。

Based on the analysis of coupled interaction between backfilling body and key aquiclude strata(KAS),a mechanical model of KAS nonlinear seepage stability under backfill mining conditions was established,criterion of KAS nonlinear seepage instability in backfill mining was proposed,and the quantitative relationship between KAS nonlinear seepage instability and backfilling ratio was studied.The results have shown that pronounced horizontal and vertical zoning patterns present in the rock mass permeability in fracture zone above goaf:In the horizontal direction,it gradually decreases from coal wall to goaf center and approaches a fixed value;along the vertical direction it follows a logarithmic gradual attenuation pattern.The field measurement results have shown that after backfill mining,the fracture damage develops to lower rock strata of composite KAS,and resistivity monitoring value was about 40~50Ω·m.No water seepage or gushing in the working face was observed,and the control effect of KAS was excellent,ensuring safe mining of coal resources under the aquifer.