大倾角伪俯斜异形采场支架与围岩耦合作用及分区控制

Coupling effect and partition control of support and surrounding rock in steeply dipping pitching oblique special-shaped stope

  • 摘要: 为研究大倾角伪俯斜异形采场“支架−围岩”耦合作用机理及其力学响应,采用现场实测、理论分析、三维物理模拟试验、Rhino+Kubrix+FLAC3D数值计算相结合的研究手段,深入分析了伪俯斜工作面开采不同区域滑移矸石和破断顶板与支架的作用机理,揭示了伪俯斜环境下支架的力学响应特征及架间作用规律。结果表明:大倾角伪俯斜采场“支架−围岩”关系受多系统间相互影响,采场各区域顶板岩梁破断位置及来压步距不同,顶板的垮落滑移特征及不同层位破断顶板对支架的作用形式及强度区域性各异,支架三维受载各向异性。下部区域顶板支架正接触,护帮板支护煤壁,对相邻支架影响较小;滑移矸石及破断顶板作用于中部支架掩护梁及架间,支架发生抬头、倾倒、扭摆,“矸石−支架−支架”系统动态失稳,架间挤压、后推最为剧烈;上部“支架−围岩”关系易由正压转化为上下错动及顶梁分开状态,造成上方顶板沿掩护梁切顶局部破坏。伪俯斜支架梯阶错位布置,支架不同部位及架间应力非对称分布转移。正常开采时,中部区域支架后立柱侧向压应力集中,顶梁后端非对称受拉,下部区域架间底部应力分布不均,中上部区域架间法向应力集中;来压期间,支架侧向压应力向右后立柱集中偏转,上部顶梁及顶−掩铰接处拉应力增加明显,沿倾斜延伸易斜向偏载。最大法向应力转移至中部架间顶梁后端,最大切向应力转移至上部支架底座间,下部区域架间挤咬程度降低。结合工程实际,针对支架非均衡受载失效、动载冲击及架后顶板切落等动力灾害问题,提出了支护系统分区控制、增强矸石充实程度、优化支架结构等一系列异形采场“支架−围岩”区域性稳定控制措施,保证了伪俯斜工作面的安全开采。

     

    Abstract: In order to study the coupling mechanism and mechanical response of “support-surrounding rock” in steeply dipping pitching oblique special-shaped stope, field measurement, theoretical analysis, three-dimensional physical simulation experiment and Rhino + Kubrix + FLAC3D numerical calculation were used to analyze the mechanism of slip gangue and broken roof on support in different areas of pitching oblique working face, and the mechanical response characteristics of support and the law of action between supports in pitching oblique environment are revealed. The results show that the relationship between “support-surrounding rock” in the steeply dipping pitching oblique stope is affected by the interaction of multiple systems. The breaking position and weighting step distance of the roof rock beam in each area of the stope are different. The caving and sliding characteristics of the roof, the action form and strength of the broken roof in different layers on the support are different in different regions, and the three-dimensional loading anisotropy of the support is different. The roof support in the lower area is in direct contact, and the coal wall is supported by the guard plate, which has little influence on the adjacent support. The sliding gangue and the broken roof act on the middle support shield beam and between the supports, and the support is raised, toppled, and twisted. The “gangue-support-support” system is dynamically unstable, and the extrusion between the supports, and the pushback are the most severe. The relationship between the upper support and the surrounding rock is easily transformed from positive pressure to the upper and lower dislocation and the roof beam is separated, resulting in the local failure of the upper roof along the shield beam. The pitching oblique support is arranged in staggered steps, and the stress distribution in different parts of the support and between the supports is transferred asymmetrically. During normal mining, the lateral compressive stress of the rear column of the support in the middle area is concentrated, the rear end of the top beam is asymmetrically pulled, the stress distribution at the bottom of the lower area is uneven, the normal stress between the middle and upper areas is concentrated. During the weighting period, the lateral compressive stress of the support is concentrated and deflected to the right rear column, and the tensile stress of the upper top beam and the top-shield hinge increases obviously, and it is easy to be inclined and eccentrically loaded along the inclined downward extension. The maximum normal stress is transferred to the rear end of the top beam between the middle frames, the maximum tangential stress is transferred to the upper bracket base, and the degree of inter-frame squeezing in the lower area is reduced. Combined with engineering practice, aiming at the problems of dynamic disasters such as unbalanced load failure of support, dynamic load impact and roof cutting after support, a series of regional stability control measures of “support−surrounding rock” in special-shaped stope, such as partition control of support system, enhancement of gangue filling degree and optimization of support structure, are put forward to ensure the safe mining of pitching oblique working face.

     

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