【作者】 陈登红；

【导师】 华心祝；

【作者基本信息】 安徽理工大学 ， 采矿工程， 2014， 博士

【摘要】 随着煤矿开采深度的增加,回采巷道围岩变形量大、支护体变形失效多、巷道断面收缩严重等矿压显现强烈,有关深部回采巷道围岩变形破坏机理及支护技术的研究越来越成为确保工作面安全高效生产的重要课题。以淮南矿区13-1煤回采巷道赋存及工程条件为背景,在调研深部典型回采巷道支护及围岩变形破坏现状的基础上,开展深部典型回采巷道围岩变形破坏特征及控制机理研究,采用地应力实测、相似模拟、数值模拟、理论分析和现场实测等综合研究方法对深部典型回采巷道围岩变形破坏特征及控制机理进行了系统的研究,主要研究内容和结果如下：1)分析深部回采巷道地质工程条件,开展围岩力学参数、地应力参数测试及掘进回采期间矿压显现规律研究,获得深部典型回采巷道的围岩力学及矿压显现特征。2)在深部煤炭开采与环境保护国家重点实验室开展了大尺寸、真三轴应力下煤巷围岩变形破坏特征的模型试验研究。获得了浅埋静水压力、深埋静水压力、初掘采动应力(k=1.5倍900m埋深静水压力,后同)及回采动压(k=2～4.5)等不同应力环境下矩形、直墙拱形共四种尺寸的煤巷围岩应变、变形及破坏特征,结果表明：随加载压力增加,煤巷围岩经历了小应变、浅部拉伸深部压缩的分区应变到高应力下拉应变区范围不断扩展的变化过程,获得了拉压分区应变产生的条件：顶底板、载荷集度介于900m静水压力～k≤2之间、直墙拱形更易出现,研究还发现高应力下拉应变扩展范围超锚索支护长度。监测底鼓随加载压力变化表明：高应力是巷道底鼓量大、底鼓速度加快的主要原因,断面形状对底臌也有一定的影响,直墙拱形较矩形小。断裂丝监测结果显示：巷道破坏先后顺序为：巷帮首先发生破裂,进而传递到底角,最终巷道顶板产生明显离层；试验还得到大断面预留大变形是深部典型回采巷道围岩稳定性控制的有效途径之一。3)数值模拟研究深部典型回采巷道围岩稳定性影响因素(采高、面长、埋深、锚索支护体长度)结果表明：(1)回采巷道初掘期间,应变软化是围岩稳定性的主要影响因素。软化模量为Q=2.0GPa时深部典型回采巷道的围岩变形和矿压实测结果更为吻合,且软化后巷道围岩塑性区内出现较多范围的拉破坏区,与模型试验结果一致。(2)工作面回采期间,采用单因素法分析了四因素对面前方回采巷道两帮老顶支承压力峰值的影响,获得了相应的峰值应力变化规律。(3)采用极差分析法确定埋深是影响回采巷道围岩稳定性的主要影响因素,拟合得到了四因素随埋深变化关系式,相关性很好,结果表明：帮部围岩变形呈线性增加,顶底移近呈指数增长,随埋深增加,帮部增速较顶底快,埋深900m时,各移近量相当,加强帮部支护和控制顶板离层应并驾齐驱。4)初掘期间,基于M-C、D-P准则,按应变软化、碎胀扩容条件分析了深部软化区、残余区范围的影响因素,研究发现同梯度增加的软化模量、支护力(△Q=1GPa、△Pi=0.15MPa)对巷道围岩软化区、残余区范围的影响,初始段较后续段大,基于D-P准则简化计算得到走向高应力是软化区、残余区范围增长的不利影响因素之一,代入典型条件煤巷参数计算分析了软化区、残余区范围,发现残余区范围超过一般帮锚杆支护长度(小于等于2.5m),需加强帮部支护。5)回采期间,基于损伤理论、材料力学理论,构建了坚硬老顶“梁”模型研究了工作面侧、实体煤侧巷道深部围岩弹塑性交界处顶板压力大小对老顶挠度的影响。研究发现随老顶垂直压力增加,挠度增加很快；同时其最大挠度位置随压力大小及距巷表距离发生改变。依据最大拉应力破坏准则,分析了坚硬顶板的拉破断特征,计算得到高应力下巷道顶板基本处于拉破坏失稳阶段。6)为防止拉破坏失稳,提出帮角顶板加强支护减少顶板下沉位移,依据超静定梁的求解步骤,采用解除约束的办法分析老顶岩梁受力变形,求出作用于顶板的支护力及其挠度曲线,得出了巷道上方顶板反弹的曲线,理论上解释了顶板压缩变形及压缩区存在的可能。7)在总结模型试验、数值计算、理论分析等深部典型回采巷道围岩变形破坏特征的基础上,提出“开掘方向优化”、“强帮护两侧顶”、“断面形状优化”、“分区分级加强”等控制原则,并优化同类条件破坏变形严重的回采巷道支护方案,方案实施后,深部典型回采巷道围岩变形量明显减小,工程效果良好。更多还原

【Abstract】 With the increment depth of coal mining, the strata behavior severely, such as the characteristics of large deformation, lots of support deformation and failures, severe contraction(shrink) gateway section and so on during excavation and mining period. It was became a more and more important subject that studing on supporting mechanism of deep gateways and the supporting technology to ensure coal mine safety and efficient production, Based on the condition of13-1coal seam typical gateways and reseaching on the situation of the support and deformation of gateways’surrounding rock of Huainan deep mine, the destruction characteristic and control mechanism of surrounding rock were studied, Complex research methods were adopted such as in-situ measurement, similarity simulation,numerical simulation and theoretical analysis for mastering the destruction characteristic and control mechanism of surrounding rock on typical gateways under deep depth. The main research contents and results are as follows:1) Based on the surrounding rock conditions of deep typical gateways, by carring out the test of mechanics and in-situ stress parameters and studing strata behavior,its character was obtained.2) The three axials model test on deformation characteristic of typical gateway surrounding has been done in the State Key Laboratory Deep Coal Mine&Environment Protection.the strain,deformation and destruction character of four sections gateways with rectangle and straight wall semicircle arch type was obtained on condtions of different load pressure such as shallow and deep hydrostatic pressure, excavtion stress(k=1.5times to the depth of the900m hydrostatic pressure, the same after) and mining stress(k=2～4.5).The result shows:the strain on surrounding rock of gateway was changed from small,shallow tension and deep compression strain partition and tension strain area was gradually englarged under high stress.the conditions of stress partition were:roof and floor,load pressure between900m hydrostatic pressure and k≤2and the semicircle arch type gateways is more prone to this phenomenon,the tension strain area were out of the anchor support during high stress.Floor heave monitoring shows that which was main caustion for floor heave deformation speed was high stress,a certain impact for the section shape different such as the semicircle arch type was smaller than rectangle, wire breakage shows the order of destruction was:sidewall was destroyed firstly and then damage transferred to floor angle,at last obvious separation was produced on roof. Reserved large deformation by larger section was acquired by the test.3) The result by numerical simulation on factors of stability on deep typical gateways surrounding rock shows:during excavation, strain softening was the main factors on stable of surrounding rock.The deformation of surrounding rock was more similar to site while Q=2.0(strain softening parameters) and constantly large tension plastic zone area appeared, Consistent with the model test results.(2) during mining period, the four factors’affection of stress on two sidewall’s main roof were studied by single factor analysis and the laws were agained.(3) The depth was main factor to surrounding rock deformation by the variance methods.The expression of relation between four factors and depth were fitted,good correlation,it shows:the sidewall dformation increasd lineral with depth, roof and floor deformation exponential growth.The former enlarge faster than the later, the depth was going to900m,each section was simlar,therefore enhanced sidewall support was as same as roof support.4) Based on M-C, D-P criterion, strain soften, broken expansion, factors on soften area and expansion area range were studied,it shows:the influence to the range of soften and residual area,initial enlarge taken more actions than later enlarge by the same gradient(△Q=1GPa、△Pi=0.15MPa).Based on D-P criterion,the strike high stress was one of the negative factors for two area.Take typical conditions parameters into the expression,the residual area was out of common anchor support length(≤2.5m), sidewall support needs to be enhanced.5) Based on damaged theory and materials mechanics theory,"beam" model was made to analysis hard roof stability during mining period by deflection changed. The deflection increased quickly while the vertical stress on roof increased, and the distance of maximum deflection changed. Based on the maximum tensile stress criterion,tensile fracture characteristics of hard main roof were studied and largely belongs to tensile failure stage.6) In order to prevent tensile failure, the roof on sidewall angle were enhanced to reduce deflection. On the basis of solving steps of hyperstatic beams,deformation of main roof were studied by constraint relief measures,the rebound curve of main roof were acquired, the compression area could be expained by this theory.7) Based on stuy of defomation and destruction on surrounding rock deep typical gateways,"optimization of excavation direction","strengthen sidewall support and lateral roof suppot","optimization on section of gateways","different support stress during different area" were mentioned and support shceme was optimizated under similar conditions for severely defomation and destruction, after implemented, the deformation of surrounding rock gateways were reduced obviously, good effect has been acquired.更多还原