深部高应力巷道锚杆支护优化设计研究

发布时间：2018-08-31 07:20

【摘要】：随着浅部煤炭资源的逐渐枯竭,一大部分矿井都将转入或即将转入深部开采,开采向深部发展成为煤炭开采的必然趋势。煤矿进入深部开采阶段,受到深部特殊地质力学环境的影响,围岩的力学性质发生了很大变化,表现为特有的不利于巷道稳定的力学特征,给巷道围岩控制带来很大的困难。目前,在深部高应力巷道锚杆支护参数设计方面还缺乏足够的科学依据,存在一定的盲目性,造成支护强度和成本的不合理,因而还应开展大量的工程实验及理论研究工作。本论文以国家自然科学基金项目“深井巷道围岩弱化规律及高强锚固群围岩控制机理研究”为依托,并紧密结合现场工程实际,对深部高应力巷道围岩大变形破坏特征进行了大量的现场调查研究,认为该类巷道主要表现为围岩变形量大,变形速度快,变形具有显著的塑性,变形持续时间长,两帮内挤严重,出现支护体部分或完全失效而破坏,并产生较大的底鼓变形和破坏。采用弹塑性力学、工程力学、岩石力学等理论对巷道开挖后的围岩稳定性力学状态进行了分析,建立了力学计算模型,推导出了深部巷道围岩塑性区半径的计算公式,对锚杆长度的选择提供了依据。运用数值分析方法,并基于正交试验方法,结合平煤十矿戊9、10-20160工作面风巷实际情况进行了锚固支护参数的正交数值试验,确定了13因素3水平共27种不同的计算模型,分别进行了数值模拟,对模拟结果进行了多指标的极差分析,得到了巷道的最优支护方案为:①顶板支护参数:锚杆长度2.6m,锚杆直径22mm,锚杆间排距0.75m×0.8m,锚杆预紧力60KN,锚索长度7.3m,锚索直径17.8mm,锚索间排距2×3m,锚索预紧力150KN;②两帮锚杆支护参数:锚杆长度2.4m,锚杆直径22mm,锚杆间排距0.8m×0.8m,顶角锚杆与顶板夹角25°,帮角锚杆与底板夹角25°。运用MATLAB软件分别进行各矩阵的计算得到两帮移近量、顶板下沉量、顶底板移近量的回归方程式及对应的回归系数,通过回归方程式对巷道两帮移近量、顶板下沉量以及顶底板移近量进行近似的定量预测。运用数值模拟方法对让压管不同的让压点进行模拟分析,得到高强预应力让压锚杆最佳让压点为150 KN。运用数值模拟分析深部高应力巷道采用最优支护方案后,围岩变形破坏特征、应力分布规律、位移分布规律等,在巷道掘进过程中,围岩垂直应力峰值变化不明显,大致在28MPa上下波动。在掘进面前方产生应力集中,应力峰值约为28.7 MPa。开挖期间围岩垂直位移变化明显,随着开挖的进行,顶底板位移量逐渐增大,在25m处顶底板位移量接近128mm,围岩顶底板位移量增加约80mm。将经过分析得到的最优支护方案应用到平煤十矿戊9、10-20160工作面风巷,对巷道掘进期间的表面位移和锚杆受力进行监测和分析,得到围岩的顶板下沉量、顶底板移近量和两帮移近量在前期变化程度剧烈,然后逐渐趋于稳定,最终值都在允许的变化范围内,顶板锚杆、上帮锚杆、下帮锚杆受力都是呈缓慢增长趋势,最后分别趋于稳定值,通过顶板和两帮锚杆受力监测图可以看出,顶板锚杆受力超过让压管的让压起始载荷,让压管开始屈服让压,锚杆杆体仍处于弹性变形阶段,有效的阻止了锚杆的拉断。现场应用表明,锚杆支护参数设计合理有效,支护方案的优化决策结果合理,该支护方案完全可以保证巷道在服务期内的生产要求。
[Abstract]:With the gradual depletion of shallow coal resources, a large number of mines will or will soon be transferred to deep mining, mining to the deep development of coal mining is an inevitable trend. It is difficult to control the surrounding rock of roadway because of the mechanical characteristics of roadway stability. At present, there is still insufficient scientific basis for bolt support parameter design of deep high stress roadway, and there is certain blindness, which results in unreasonable support strength and cost. Therefore, a large number of engineering experiments and theoretical research work should be carried out. Based on the project of National Natural Science Foundation of China "Study on the law of surrounding rock weakening in deep mine roadway and the control mechanism of surrounding rock with high-strength anchorage group", and in close connection with field engineering practice, a large number of field investigations and studies have been carried out on the characteristics of large deformation and failure of surrounding rock in deep high-stress roadway. The deformation speed is fast, the deformation has remarkable plasticity, the deformation duration is long, the two sides are extruded seriously, the supporting body is partly or completely invalidated and destroyed, and the large floor heave deformation and destruction are produced. Based on the mechanical calculation model and the formula for calculating the radius of plastic zone in the surrounding rock of deep roadway, the basis for choosing the length of bolt is provided. With the numerical analysis method and the orthogonal test method, the orthogonal numerical test of bolting support parameters is carried out in combination with the actual situation of the air roadway in No. There are 27 different calculation models in element 3 level, and the numerical simulation results are analyzed by multi-index range. The optimum supporting schemes are obtained as follows: 1. Roof supporting parameters: bolt length 2.6 m, bolt diameter 22 mm, bolt row distance 0.75 m *0.8 m, bolt preload 60 KN, bolt cable length 7.3 m, bolt cable diameter 17.8 mm, bolt cable diameter. The distance between cables is 2 *3 m and the pretension force of cables is 150 KN. The regression equation and the corresponding regression coefficient are used to approximate the quantitative prediction of the approximate displacement of the two sides of the roadway, the roof subsidence and the roof-floor displacement. The numerical simulation method is used to simulate and analyze the different concessions of the concessional pipe, and the optimum concessional point of the high-strength prestressed concessional anchor is 150 KN. The paper intends to analyze the deformation and failure characteristics, stress distribution law and displacement distribution law of surrounding rock after adopting the optimal supporting scheme in deep high stress roadway. During the course of roadway excavation, the peak value of vertical stress of surrounding rock does not change obviously and fluctuates about 28 MPa. Stress concentration occurs in front of the roadway, and the peak value of stress is about 28.7 MPa. The displacement of roof and floor increases gradually with the excavation. The displacement of roof and floor approaches 128 mm at 25 m and the displacement of surrounding rock increases about 80 mm. The optimal support scheme is applied to the wind tunnel of No. 10 Mine of Pingdingshan Coal Mine during the excavation period. Through monitoring and analysis, the roof subsidence, the roof and floor displacement and the two-side displacement of the surrounding rock changed sharply in the early stage, then gradually stabilized, and the final values were within the allowable range of change. The roof anchor, the upper-side anchor and the lower-side anchor force showed a slow growth trend, and finally reached a stable value respectively through the roof and the lower-side anchor. It can be seen from the stress monitoring diagram of the two sides of the bolt that the force of the roof bolt exceeds the initial load of the pressure concession pipe and the pressure concession pipe begins to yield. The bolt body is still in the stage of elastic deformation, which effectively prevents the bolt from breaking. The protection plan can completely guarantee the production requirements of the roadway during the service period.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353.6

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