采场覆岩应力及垮高的柱宽效应三维相似模拟研究

基于采场应力分布的动态性特点,以谢桥矿1151(3)综放工作面地质和开采条件为背景,采用实验室相似材料模拟方法,研究不同煤柱宽度条件下采场覆岩应力分布和垮落特征。研究表明,不同煤柱宽度上覆岩层应力分布及垮落高度有所不同。随煤柱宽度的增大,倾向方向工作面前方应力峰值区由原来的煤体上方逐渐向煤柱上方转移,且峰值逐渐增大,工作面后方煤柱承载上覆岩层主要荷载和压力,且随煤柱宽度增大应力峰值也增大。工作面上覆岩层垮落形成由高应力束组成的应力壳,应力壳对上覆岩体的荷载和压力起主要支撑和传递作用,随着煤柱宽度的增大,应力壳的高度逐渐减小,在煤柱及煤体内形成的壳基也逐渐发生变化和转移,壳基在煤柱内从无到有,壳基的应力集中程度也逐渐增强,煤柱内单位体积的岩块承载的荷载和压力也从小到大,再由大变小。

3D Analog Simulation of Pillar Width Effect of Stress and Caving Height of Overlying Strata

Based on dynamic characteristic of stress distribution of mining field and geological and mining conditions of 1151(3)Full-mechanized Caving Mining Face in Xieqiao Colliery,this paper applied analog simulation to researching stress distribution and caving characteristics of overlying strata under different pillar widths.Results showed that stress distribution and caving height were different for different pillar widths.With pillar width increased,stress peak zone of mining face migrated from above coal body to above pillar and stress peak increased gradually.Pillar behind mining face bear the main load of overlying strata and its pressure peak increased with pillar width increased.Overlying strata caving formed stress shell grouped by high stress bundles.Stress shell played a role of bearing load of overlying strata and transferring pressure.With pillar width increased,height of stress shell gradually decreased and shell basement which formed in coal pillar and coal body changed and migrated.Stress shell basement formed in pillar and stress concentration degree gradually strengthened.Loading and pressure in unit volumetric coal was from small to large,then from large to small.