煤层底板破坏的断层效应模拟及其在防治水中的应用

Simulation of Fault Effect on Mining Failure of Coal Seam Floor and Its Application in Water Disasters Control

梁北煤矿已发生5次寒武系灰岩底板突水事故,造成重大经济损失。根据矿井的水文地质条件,建立了煤层开采的FLAC数值模型,利用岩石力学及渗流力学理论,分别模拟了无断层和有断层条件下煤层底板采动破坏带的演化规律,重点讨论了断裂深度及断层空间位置对底板破坏深度的影响。结果表明,断层的存在可使底板采动破坏深度增加20%~33%,断层是突水重点防范区域,遇断层前10m直到过断层15m须加强防治水工作。根据模拟结果设计了梁北矿11041,11151,11111三个工作面底板的注浆加固工程,重点注浆层位分别为底板破坏范围和寒武系顶部裂隙发育带,注浆工程增强了底板的阻水能力,实现了工作面的安全回采。

Five water inrush events happened in Liangbei coal mine. The water source was from the confined Cambrian karst aquifer under the coal seam. According to the hydrogeological conditions of Liangbei coal mine, the numerical models, including non-fault and fault models, were established with FLAC package. Based on the theory of rock mechanics and seepage mechanics, numerical simulations were directed for revealing the failure evolution of the seam floor above the high pressure confined aquifer. Different fault factors such as fault depth and location controlling the failure of coal seam floor were discussed. Simulation results showed that failure depth for the fault model increased 20%-33% compared to the non-fault model. The fault zone, especially the area of 10 meters ahead of the fault to 15 meters behind the fault, must be paid more attention to. Accordingly, the grouting reinforced projects were designed for No. 11041, 11151, 11111 working faces in Liangbei coal mine. Targeting the failure zones of coal seam floor and fractures on top of the confined Cambrian karst aquifer, the grouting projects reinforced the water-resisting strength of the coal seam floor, which assured the safe mining in Liangbei coal mine.