【作者】 孙毅；

【导师】 曹胜根；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2017， 硕士

【摘要】 为提高煤炭采出率和资源利用率、延长矿井服务年限,不少矿井准备或正在回收矿井保护煤柱。由于保护煤柱受两侧工作面的采动影响,因此其在回采时工作面应力集中程度大,巷道维护困难。本文以盛平煤矿西大巷保护煤柱为研究背景,综合运用理论分析、数值模拟和现场试验等方法,系统研究了两侧采动影响下煤柱内支承应力和塑性区分布规律、煤柱内回采巷道合理位置及支护技术,取得的研究成果如下:(1)针对煤柱两侧采空区空间分布情况的不同,分别建立了两侧采空模型和采空区拐点模型,(1)两侧采空时煤柱内支承应力集中,采空区侧应力呈“Λ”分布,集中系数为2.8,受采动影响的塑性区范围约为0~40m;(2)采空区拐点处支承应力呈扇形分布,应力峰值系数约为2.3,采空区塑性区范围缩小到35m;(2)研究煤柱内巷道掘进阶段不同煤柱宽度下,巷道围岩应力和变形的变化规律,分析将巷道布置在应力降低区或原岩应力区的合理性,并由此划分了回采巷道合理位置的范围:回风平巷侧煤柱宽度为4m~6m,运输平巷侧煤柱宽度为20m~40m;(3)煤柱工作面回采阶段,工作面超前支承应力与采空区周围支承应力相互叠加,应力集中程度升高。研究工作面推进过程中,不同煤柱宽度下巷道围岩应力分布规律,当煤柱回采时,巷道围岩应力环境发生变化,部分掘进期间正常使用的巷道出现较大变形,并由此确定了回采巷道合理位置:回风平巷侧煤柱宽度为5m,运输平巷侧煤柱宽度为30m;(4)针对煤柱回采时巷道围岩变形严重,提出了高预高强度锚杆支护技术,并对锚杆间距对巷道围岩的控制机理进行研究,发现锚杆间距不大于900mm时,锚杆压应力场会在巷道围岩浅部相互叠加形成承压拱;尤其针对回风平巷巷道两帮变形不对称的特点,提出非对称支护技术,并确定了合理的巷道支护参数:煤柱帮锚杆间排距为700mm×800mm,开采帮为850mm×800mm。现场工业性试验结果表明:研究成果有效控制了巷道围岩变形,为煤柱工作面成功回采创造了有利条件,并对类似煤柱的回收提供了借鉴意义。更多还原

【Abstract】 It is important for improving the coal recovery rate and resource utilization ratio and prolonging the mine life to exploit protection coal pillar.When coal pillar is extracted,the stress concentration in the working face is large and the roadway maintenance is difficult.This paper systematically studied the bearing stress and distribution of plastic zone in the pillar under the influence of mining of two sides,the reasonable position of roadway and supporting tech nology,with Shengping Mine for research background,by using theoretical analysis,numerical simulation and field test.The main research achievements are as follows:(1)Established the models of isolated coal pillar and the inflection point of gob.(1)When the both sides of pillar is gob,the distribution of bearing stress near gob likes “Λ”.The concentration coefficient is 2.8,and the range of plastic zone affected by mining is about 0~40m;(2)At the inflection point of the gob,the support stress is fan-shaped.The stress concentration factor is about 2.3,and the plastic area range decreases to 35m;(2)Studied on stress distribution and deformation of roadway surrounding rock under different width of coal pillar in tunneling stage.Analyzed the rationality of the layout of the roadway in the stress reduction zone or the original rock stress zone and thus divided the scope of reasonable position of roadway: the width of the pillar near airway is 4m~6m,the width of the pillar near another roadway is 20m~40m;(3)During the mining stage,the pre stress of the working face and the support stress around the gob overlap with each other.Studied stress distribution of roadway surrounding rock under different width coal pillar during the mining process.And the reasonable location of the roadway was determined: the width of pillar near airway is 5m and the width of another pillar is 30m;(4)In view of the serious deformation of the surrounding rock in coal pillar mining,the bolt support technology with high pre-stress and high strength was put forward study.And studied the control mechanism of bolt density,found that when the spacing between the bolts is lower than 900 mm,the compressive stress field of the bolt will overlap with each other in the shallow part of the surrounding rock to form a compression arch.The asymmetric support technology is put forward and the reasonable supporting parameters of roadway are determined: The spacing between the bolts in pillar wall is 700 mm ×800mm,and the other one is 850 mm × 800 mm.Field industrial test results show that the research results effectively control the deformation of roadway surrounding rock and provide reference for the recovery of similar coal pillars.更多还原