充填回收房式煤柱围岩变形及煤柱承载特征物理模拟研究

Physical simulation for surrounding rock deformation and coal pillar bearing characteristics of filling recovery room coal pillar

为探明风积沙综采固体充填回收房式煤柱采场围岩稳定性特征,采用相似物理模拟方法对比分析了垮落法与充填法回收时的围岩变形及煤柱受力特征,基于相似原理给出了房式开采、垮落法及充填法回收房式煤柱的过程与时间控制方案,确定采用纸张+塑料泡沫+海绵按比例组合并预压缩的方式模拟风积沙充填物料的压缩变形特性。研究发现:(1)相比垮落法,风积沙充填回收煤柱时可大幅减缓覆岩下沉速度,延后及延长覆岩移动周期,避免垮落法回收时因基本顶及上覆坚硬岩层来压剧烈导致的煤柱失稳、煤房垮塌;(2)垮落法与充填法回收时,煤柱的最大承载均出现在超前第1排煤柱上,充填回收可大幅降低超前煤柱的整体承载与应力大小,消除煤柱上的动载现象。

To investigate the force and stability of surrounding rock in recovering standing pillars with aeolian in fully-mechanized solid backfilling mining working face, the similar physical simulation method was used to compare and analyze the deformation of the surrounding rock and the stress characteristics of the coal pillar when the caving method and the backfilling method were used. Firstly, based on the similarity principle, the methods to simulate process and time control room mining stage, caving to recover pillars stage and backfilling to recover pillars stage were given, while the precompression of paper, plastic foam and sponge combination were chosen to simulate the stress-strain characteristics of aeolian backfilling material. The results showed that: 1) Comparing with caving method, backfilling with aeolian could reduce activity of overlying strata movement, delay and extend period of overlying strata movement, also could avoid failure of pillars and room roof caused by periodic weighting of main roof and hard formation in caving mining working face;2) The maximum load were both found at the first rank pillars in front of working face whether caving method or backfilling was used to recover standing pillars, backfilling method could effectively reduce the overall load and the stress of standing pillars, and eliminate the phenomenon of dynamic load damage on these standing pillars.