China Energy Shendong Coal Group Co Ltd
School of Energy, Key Laboratory ofWestern Mine Exploitation and Hazard Prevention of the Ministry of Education, Xi'an University of Science and Technology
Cuncaota No.2 Coal Mine, China Energy ShendongCoal Group Co Ltd

针对浅埋近距离煤层工作面过上覆三角形遗留煤柱开采,存在顶板局部来压强烈和区段煤柱应力集中导致的巷道大变形等问题,以寸草塔二矿 31109 工作面为研究背景,采用现场实测、数值计算和理论分析相结合的方法,研究过三角形煤柱两次采动叠加应力的大小和范围的演化规律,揭示两次采动区段煤柱压力变化规律和相邻巷道破坏机理,明确巷道加强支护的范围和重点支护范围与时机。 研究结果表明:上覆三角形斜交煤柱对其下方工作面煤层形成应力集中,最大应力位置位于斜交区段煤柱之下;当下煤层 31206 工作面开采后,31109 区段煤柱应力上升为最大应力,应力峰值区位于与上覆斜交区段煤柱叠合区附近,峰值区宽度为 240 m,对应该区域巷道变形破坏较明显。 31109 工作面开采过程中,在工作面煤壁与上覆斜交煤柱叠加区和工作面区段煤柱与上覆斜交煤柱叠加区存在应力峰值区,形成应力双峰;随着工作面推进,双峰应力不断升高,且煤壁应力峰值区逐步向区段煤柱方向移动,当工作面推进到区段煤柱叠加区时,双峰合并为更高的单峰应力;在工作面出斜交煤柱时区段煤柱应力达到最大,出煤柱叠加区后应力迅速减小;总体上,31109 工作面开采后区段煤柱应力峰值区最大应力高 56% ,峰值区范围扩大 50% 。 区段煤柱应力升高的机理是随着工作面的推进,上覆三角形斜交煤柱尺寸不断减小,应力集中程度不断提高;当工作面推进到三角形煤柱端区时,斜交煤柱应力、工作面超前支承压力、区段煤柱应力相互叠合,形成区段煤柱应力峰值区,在工作面出煤柱时(三角形煤柱尖端)形成应力核区,引起该区段煤柱变形和巷道破坏。 据此,提出在 31109 工作面开采前,对应力峰值区和核区巷道进行锚索和注浆补强支护,现场工业性试验取得良好效果,保障了 31109 工作面过三角形斜交煤柱区安全回采。

Aiming at the influence of the overlying coal pillar of working face in shallow coal seam,there are problems such as strong ground pressure and large deformation of the roadway caused by stressconcentration of the section coal pillar. Taking the 31109 working face of Cuncaota No.2 coal mine asthe research background, the combined method of field measurement, numerical calculation and theoreti-cal analysis was adopted. The evolution law of the size and range of superimposed stress through the tri-angular coal pillar under two mining stages were mastered, the changing of coal pillar pressure in the twomining stages and the damage mechanism of adjacent roadways were revealed, the scope of roadway en-hanced support and the scope and timing of key support were clarified. The research results show that:the overlying triangular diagonal coal pillars cause stress concentration on the working face of lower coalseam, and the maximum position is located under the diagonal coal pillar. After the 31206 working facein lower coal seam was mined, the stress of the coal pillar in the 31109 working face increased to themaximum stress, the stress peak area was located near the overlapping area of the coal pillar in the over-lying diagonal section, the width of the peak area was 240 m, the deformation and damage of the road-way in this area was more obvious. During the mining process of the 31109 working face, there werestress peak areas in the overlapping area of the coal wall, the coal pillar and the overlying oblique coalpillar, they form stress double peaks. As the working face advanced, the stress of the double peaks con-tinuously increased. Moreover, the stress peak area of the coal wall gradually shifted towards the direc-tion of the section coal pillar. When the working face reached the section coal pillar overlay area, thedouble peaks merge into a higher single peak stress. The section coal pillar stress reaches the maximumwhen the working face emerges from the oblique coal pillar, and the stress decreases rapidly after exitingthe coal pillar overlay area. In general, the maximum stress in the stress peak area of the section coal pil-lar after mining in the 31109 working face increased by 56% , and the range of the peak area expandedby 50% . The mechanism of increasing stress in section coal pillar is that with the working face advances,the size of the overlying triangular diagonal coal pillars continuously decreased, and the degree of stressconcentration continuously increases. When the working face advances to the end area of the triangularcoal pillar, there is an overlap and mutual interaction between the stress in the oblique intersecting coalpillars, the advance support pressure of the working face, and the stress in the segmental coal pillars.This interaction results in the formation of a stress peak zone in the section coal pillar. When the theworking face out the boundary of coal pillar ( triangular coal pillar apex ), it creates a stressconcentration zone, leading to deformation of the segmental coal pillars and damage to the roadway inthat area. Based on this observation, it is proposed to carry out anchor cable and grouting reinforcementsupport for the stress peak area and core area of roadway before mining in the 31109 working face. On-site industrial test achieved good results, ensuring the safe mining of the 31109 working face passingthrough the triangular oblique coal pillar area.

国家自然科学基金项目(52074211,52304153)

1 工程背景
1.1 工作面概况
1.2 工作面巷道变形实测
2 过斜交煤柱开采集中应力演化规律
2.1 三角形斜交煤柱的数值模型
2.2 三角形煤柱引起的3-1煤层采前支承压力分布
2.3 三角形斜交煤柱下开采的支承压力演化规律
2.3.1 31206工作面开采时区段煤柱应力演化规律
1) 31206工作面开采过程中31109区段煤柱支承压力演化规律
2) 区段煤柱叠合应力区巷道破坏机理
3) 三角形煤柱应力核区
2.3.2 31109工作面过斜交煤柱开采应力演化规律
1) 工作面煤壁超前支承压力峰值演化规律
2) 31109工作面区段煤柱应力演化规律
3 斜交煤柱强矿压机理与支护对策
3.1 三角形斜交煤柱集中应力叠合特征
3.2 三角形斜交煤柱影响下巷道变形破坏机理
3.3 三角形斜交煤柱二次采动巷道支护对策
4 结 论