【作者】 鞠金峰；

【导师】 许家林；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2013， 博士

【摘要】 神东矿区是我国典型的浅埋近距离煤层赋存矿区，现已逐步进入第2层主采煤层的开采。由于上煤层开采遗留煤柱的影响，下煤层工作面在推出此类煤柱前后5m左右的范围内常易出现支架活柱瞬时大幅下缩的压架现象。据不完全统计，自2007年以来已累计发生类似案例7起，直接经济损失近亿元，严重影响着矿区的安全高效生产；如何确保出煤柱开采的安全，已成为矿区亟待解决的重大技术难题。论文综合采用现场实测、理论分析和模拟实验等手段，就浅埋近距离煤层出煤柱开采压架发生的机理、影响因素、发生条件及其防治对策等进行了深入的研究。针对浅埋近距离煤层出两侧采空煤柱和一侧采空煤柱这2种开采类型，从煤柱上方关键块体破断运动的角度，揭示了各自压架灾害发生的机理。出两侧采空煤柱时，煤柱上方关键层破断块体将与采空区一侧已断块体形成拱形的三铰式结构，由于该结构始终无法达到稳定的承载状态，其相对回转运动将造成上覆岩层的载荷全部施加到支架之上，最终导致压架。出一侧采空煤柱时，受切眼在煤柱下布置位置的影响，其压架存在2种情况：当切眼距煤柱边界较远而大于煤柱上方关键层的初次破断距时，则出煤柱时该关键层将处于周期破断状态，此时的压架机理与出两侧采空煤柱时相同。当切眼距出煤柱边界较近而介于煤柱上方关键层的初次破断距和周期破断距之间时，则出煤柱时该关键层将呈现大跨度的悬臂式破断，由于支架处于该“砌体梁”破断结构的回转铰接点，此结构的回转运动将造成支架载荷的过大而压架。通过对影响煤柱上方关键块体回转运动的关键因素分析，掌握了出煤柱开采压架灾害的发生条件。上覆煤柱埋深越大，越易导致煤柱边界在工作面临近推出煤柱时发生超前失稳，从而促使上部关键块体提前发生反向回转，最终抑制压架的发生。而上下煤层间距越大，受覆岩以一定破断角向上发展的影响，煤柱上方关键块体滞后工作面破断的距离越长；当此滞后距离满足一定条件时，关键块体回转运动传递的载荷将仅能作用于采空区矸石之上，从而也可抑制压架的发生。由此形成了特定条件下出煤柱开采压架与否的判别准则和方法，并据此得出在神东矿区浅埋近距离煤层开采条件下，出煤柱开采的压架灾害将普遍存在。研究提出了浅埋近距离煤层出煤柱开采压架灾害的防治对策。基于关键块体回转运动的致灾机理，从促使关键块体提前回转、阻止和破坏其回转等3个方面，提出了煤柱边界预掘空巷或预爆破、煤柱边界未压实采空区充填以及煤柱边界上方关键块体结构预爆破强放的防治措施，成功指导了神东矿区补连塔煤矿和石圪台煤矿出煤柱开采压架灾害的防治实践，取得了显著的应用效果。更多还原

【Abstract】 Shendong mining area, the typical occurrence region of close distance shallow seams,.has turned into the mining of the second coal seam step by step. Due to the coal pillars leftin the upper first coal seam, many support crushing accidences happened in the mining ofthe lower second seam while the working face out of the upper coal pillar in the area5m inand out of the coal pillar boundary. Violent weighing phenomenon occurred in theaccidents, such as sharp and huge shrinkage length of support plunger in1~2minutes.According to incomplete statistics,7similar cases had happened since2007, which hadcaused nearly one million yuan of economic loses and been threatening the safe andefficient production of the coal mines in the mining area. So, how to insure the safetyduring mining out of the upper coal pillar is a significant technical problem. Based on themeans of field measurement, theoretical analysis and simulation experiment, themechanism, influencing factors, occurred conditions and the preventions of the supportcrushing disaster in close distance shallow seams are deeply researched.With the analysis of the key blocks’ breaking movement above the coal pillar, themechanism of the support crushing disaster while mining out of the upper coal pillar andgoaf-side coal pillar in close distance shallow seams was revealed respectively. Whenmining out of the upper coal pillar, the breaking block of the key stratum (KS) above thepillar and its broken block in the goaf side would form an arched three hinged structure.Due to that the structure could not reach a stable bearing state all along, all the load of theoverburden strata would be applied on the supports of the working face by the relativerotary motion of the key block structure, which finally caused the support crushing. Whenmining out of the upper goaf-side coal pillar, there would be two situations on the supportcrushing affected by the decorate position of the cut-hole under the goaf-side coal pillar. Ifthe distance between the cut-hole and the coal pillar boundary was further than the firstbreaking step of the KS above the coal pillar, the KS would present periodic breaking statewhile mining out of the pillar, and the mechanism of the support crushing was the same tothat in the mining out of the upper coal pillar. If the distance was between the periodic andfirst breaking step of the KS, the KS would present the cantilevered state with longbreaking span when mining out of the pillar, and the support crushing was caused by theexcessive load from the rotary motion of the KS structure due to that the supports wereunder the swing hinge joint of the structure.According to the analysis of the influencing key factors on the key blocks’ rotary motion, the occurred conditions of the support crushing disaster while mining out of theupper pillar had been mastered. The deeper the depth of the upper pillar, the easier to leadthe instability in coal pillar boundary occurring ahead, thus which would induce thereverted turning in upper key blocks and play a significant inhibition on the occurrence ofsupport crushing disasters. On the other hand, the further the distance between the seams,the longer the breaking position of the key block lag behind the working face by theinfluencing that the overburden strata always broke upward with a certain angle. As the lagdistance met a certain condition, the load from the rotary motion of the key blocks wouldonly act on the gangue in the goaf which can also restrain the support crushing. From theseabove, the discrimination criterion and method of the support crushing occurring whilemining out of the upper pillar in specific conditions had been formed. According to thecriterion, it was concluded that the support crushing disaster would generally exist in themining condition of close distance shallow seams in Shendong mining area.The prevention measures of the support crushing disaster while mining out of theupper coal pillar in close distance shallow seams had been proposed in the paper. Base onthe mechanism of the disaster caused by the rotary motion of the key blocks, from theaspects of prompting the key blocks to spin ahead of time, preventing or destroying itsrotation, the measure of the pre-blasting in the upper pillar boundary, the filling in the goafnear pillar boundary and the pre-blasting in the key block structure above the boundary toprevent the support crushing disaster were put forward. With the prevention measuresabove, the support crushing disaster during the mining out of the upper coal pillar inBulianta coal mine and Shigetai coal mine of Shendong mining area were preventedsuccessfully, which achieved remarkable application effect.更多还原