地下采矿引起地表塌陷机理研究

根据赤峰红岭铅锌矿的地质资料,利用颗粒流程序PFC2D建立了红岭铅锌矿的二维离散元模型,模拟矿体的开挖过程; 并通过分析开采过程中的应力和位移演化规律,揭示矿山地表塌陷区的形成机理。模拟结果表明:矿山地表发生塌陷的主要原因是矿区较大水平构造应力的释放,以及采空区未及时回填而使上盘形成悬臂结构; 塌陷废石回填了部分采空区,并在一定程度上限制了围岩的水平变形; 地表位移的缓慢变形阶段和加速变形阶段的拐点表示围岩塌陷的开始,可作为预测地表塌陷的指标。

Mechanism of Surface Subsidence Caused by Underground Mining

Based on the geological data of Hongling Lead-Zinc Mine of Chifeng Nonferrous Metal Group, a two-dimensional discrete element model for the mine was established by using particle flow code(PFC), so as to simulate the excavation process of the ore body. The formation mechanism of surface subsidence zone was revealed by analyzing the evolution law of stress and displacement during mining. Simulation results show that surface subsidence are primarily contributed by the release of the larger horizontal tectonic stress and the formation of cantilever structures in hanging wall due to the mined-out area without in-time backfilling. The subsidence leads to part of the mined-out area backfilled with the collapsed rocks, which can restrict the horizontal deformation of the surrounding rock to a certain degree. The turning point from a stage of slow deformation to an acceleration stage for the surface displacement indicates the beginning of the collapse of surrounding rock, which can be taken as an indicator to predict the ground surface subsidence.