煤巷顶板围岩结构承载能力弱化分析

Analysis on bearing capacity weakening of surrounding rock structure at roof of coal roadway

为了揭示煤巷顶板围岩承载能力的弱化机理,结合已有的研究成果,建立巷道顶板三向承载梁结构承载弹塑流弱化分析模型,确定三向承载梁结构承载状态的分析方法,提出用围岩塑性区深度、宽度、长度作为评价巷道围岩承载的弱化分析指标,研究围岩性质、支护强度、采动应用等诱导因子对煤巷顶板结构承载能力弱化分析指标的影响规律。研究结果表明:随着围岩强度的提高、支护强度的增加、扰动应力的减小,弱化分析指标呈似线性减小的变化规律,且减幅由大到小排序为塑性区长度Sy,宽度Sx和深度Sz,同时提高围岩强度、支护强度,减小采动作用应力,煤巷顶板弱化分析指标的减小程度显著高于单因子的改善。

In order to reveal the weakening mechanism of bearing capacity of the surrounding rock at the roof of coal roadway,an analysis model of bearing elastic-plastic-rheolytic weakening for the three-direction bearing beam structure at the roadway roof was established combining with the existing research achievements,and the analysis method of bearing status of the three-direction bearing beam structure was determined.It was proposed that the depth,width and length of plastic zone of the surrounding rock could be taken as the weakening analysis indexes to evaluate the bearing of roadway surrounding rock,and the influence laws of the inducible factors,such as the properties of surrounding rock,support strength,mining application and other factors,on the analysis indexes of bearing capacity weakening for the roof structure of coal roadway were studied.The results showed that the weakening analysis indexes presented an approximately linear decrease with the increase of strength of surrounding rock,the increase of support strength,and the decrease of mining action stress,and the decreasing amplitude was sorted in descending order as length of plastic zone S y,width of plastic zone S x and depth of plastic zone S z.The decreasing degree of the weakening analysis indexes for the coal roadway roof when enhancing the strength of surrounding rock and support strength and reducing the mining action stress simultaneously was significantly higher than that of singer factor improvement.