厚松散层下多煤层重复开采地表移动规律

为了研究厚松散层下多煤层重复开采对地表移动的影响，结合淮南矿区地质采矿条件，在分析顾桥煤矿重复开采地表移动规律的基础上，运用FLAC3D软件建立数值模拟模型，研究了重复开采地表变形规律，并建立了地表变形参数与采动次数之间的关系模型。研究表明:厚松散层下首次开采时地表下沉系数大于1，随着采动次数的增加，松散层逐渐被压实，地表下沉系数呈现线性增大的趋势，但3次开采后松散层已经压实，下沉系数趋于稳定，不再随采动次数增加而增大；达充分采动后，地表移动盆地范围不再增大，但受到采深增大的影响，主要影响角正切、边界角与采动次数之间均呈线性增大关系。该成果为研究厚松散层重复开采地表移动规律提供了理论依据和技术参考。 

Study on surface movement characteristics of repeated mining under thick alluvium

In order to study the influence of multi-seam repeated mining under thick alluvium on surface movement, the surface movement characteristics of Guqiao coal mine repeated mining were analyzed based on the geological and mining conditions of Huainan coal mining area. Then FLAC3D numerical simulation model of multi-seam repeated mining under thick alluvium was built, and the surface deformation characteristics and the relationship between the number of parameters and mining times were analyzed. Research results showed that when the first mining under thick alluvium surface subsidence factor is greater than 1, the alluvium is gradually compacted. The surface subsidence coefficient presents the tendency of linear increase with the mining times, but the mining subsidence coefficient tends to be stable when the mining time reaches three as the alluvium has been compacted gradually. When the goaf reaches the supercritical size, the boundary of subsidence basin is no longer increased, but is affected by the mining depth. The tangent of main effect angle and the limit angle have linear increase relationship with mining times. The results provide theoretical basis and technical reference for studying the surface movement characteristics under thick alluvium.