西部煤层开采覆岩垮落及矿压显现影响因素研究

摘要

西部矿区高强度开采引起覆岩变形-移动-破断是造成顶板大面积切落、突水溃沙等地质灾害以及水土流失等环境损伤的根源.采用数值模拟、现场微震监测和理论分析相结合的方法开展西部矿区煤层覆岩垮落及矿压显现规律影响因素研究.以小纪汗煤矿为例,开展了覆岩层变形、破断、垮落、“三带”形成规律的研究,以及不同开采速度下矿压显现规律研究,揭示了不同采高和开采速度对煤岩破坏的影响规律.现场微震监测结果表明,不同的推进速度会造成工作面不同的应力调整范围和不同的应力调整完整程度.通过2者综合分析,系统揭示了西部煤层覆岩垮落特征及“三带”形成演化规律,为建立高强度开采下覆岩结构破断规律及其稳定性判据的提出提供了科学依据.%In the western mines,the deformation,movement and breakage of overlying strata induced by high intensity mining are the root causes of geological hazards (e.g.large area roof falling,water and sand inrush) and environment damage (e.g.water and soil loss).Incorporated with numerical simulation,in-site micro-seismic monitoring and theoretical analysis,the paper study on influence factors of overlying coal strata falling and mine pressure behaviours.Taking Xiaojihan Coal Mine as an example,the deformation,breakage,falling and "three zones" formation are well discussed,the ground pressure behaviours at different mining speed are also investigated in detail,and the influence rules of different mining height and excavation speed on failure of coal strata are finally clarified.Results of in-site micro seismic monitoring show that,different mining rates of working face causes different range and completion degree of ground stress adjustment.Through comprehensive analysis,the caving characteristics of overlying coal strata and the law of "three zones" origination and evolution are systematically revealed,which will provide scientific basis for establishing failure law and stability criterion of overlying strata in high intensity mining.