近断层煤层开采的采空区地震动力响应及其对地表的影响

Seismic Dynamic Response of Goaf in Near-Fault Coal Seam Mining and its Influence on Surface

为研究近断层煤层采空区地震动力响应及其对地表的影响规律,以山西炉峪口煤矿为工程背景,基于工程波动理论,运用MIDAS GTS NX有限元软件并结合地质环境条件建立三维数值模型,对自由场地和近断层煤层开采场地采用非线性时程分析方法,计算分析其加速度响应规律、位移变化规律和塑性区分布情况。研究结果表明:在剪切地震波作用下,采空区的存在会减小其上方水平加速度峰值,改变了地表动力反应特性;采空区与断层之间会在极短时间内产生裂隙贯通,裂隙的扩张导致采空区跨落会持续加重,造成地表变形;相比自由场地,开采后下盘出露地表岩层沿软弱层面迅速产生裂隙贯通,其位移响应更大,会引起地表崩塌、滑坡等地质灾害。研究结果可以为煤矿地震动力灾害的科学防治提供一定参考依据。

In order to study the seismic dynamic response of goaf in near-fault coal seam and its influence on the surface,taking Luyukou Coal Mine in Shanxi Province as the engineering background,based on engineering wave theory,a three-dimensional numerical model was established using MIDAS GTS NX finite element software combined with geological environmental conditions.Nonlinear time history analysis method was used to calculate and analyze the acceleration response law,displacement variation law and plastic zone distribution of free site and near-fault coal seam mining site.The research results indicate that under the action of shear seismic waves,the presence of goaf will reduce the peak horizontal acceleration above it and change the surface dynamic response characteristics.Cracks will form between the goaf and the fault in a very short period of time,and the expansion of the cracks will lead to the continuous aggravation of the goaf,resulting in surface deformation.Compared to free sites,after mining,the exposed surface rock layers of the footwall quickly develop cracks and connect along the weak layer,resulting in greater displacement response and causing disasters such as surface collapse and landslides.The research results can provide a certain reference basis for the scientific prevention and control of coal mine seismic dynamic disasters.