煤矿微震监测台网优化布设研究

Study on optimal configuration of seismological observation network for coal mine

煤矿冲击矿压现象日益严峻,作为矿山动力灾害的主要监测手段,微震监测系统已在许多矿井广泛使用,为保证矿震定位和能量计算的准确,提高预测预报煤矿冲击矿压的可行性,应建立一套台网布设优化及评价系统.应用微震定位和D值优化设计理论,结合煤矿实际条件研究了影响矿震定位精度的主要因素和不利条件,并提出了采用综合指数法确定煤矿高微震活动区域和区域内矿震发生的概率,制定了台站候选点和监测区域确定的一般原则.通过理论分析震中和震源标准差反映台网定位能力的不足,建立基于数值仿真实验方法的震中与震源误差期望值模型,最终形成台网布设优化及评价系统.实验和现场应用结果表明,该系统能够快速确定台网最优布设方案,准确评价台网定位能力,满足煤矿微震监测的需要.

The rockburst phenomenon caused mostly by mining induced tremors becomes progressively more severe as the mining depth and extent increase. Microseismic monitoring technique, as the major investigation tool for the monitoring of rockburst and other mining dynamic hazards, has been widely used in many coal mines around the world. To ensure the accuracy of seismic source locating and energy calculation, and further improve the feasibility of rockburst forecasting, an optimal design and assessment system of network configuration needs to be built first. In this paper, according to practical conditions and requirements of coal mines, especially the accuracy of picking seismic wave arrivals at stations and building velocity model, the main influencing factors and bad conditions which influence the accuracy of source location were analyzed using the theory of D-optimal design and localization. A view of using the comprehensive index method to determine the high microseismic activity zones and the occurrence probability of mining-induced tremors were also proposed. Then, the general principle of choosing candidate points of geophone stations and monitoring area were established. In addition, since the location capacity of network can＇t be reflected accurately using the source standard error calculated by the traditional theoretical analysis, the model of expected epicenter and hypocenter error was created by numerical emulation experiment, and then the optimal design and assessment system of network was built up finally. The results from experiment and field practice show that, the optimal design and assessment system can be used to solve the optimal plan of network quickly, evaluate the location ability of network exactly, and can satisfy the requirements of microseismic monitoring in coal mines quite well.