多位厚层顶板双巷工作面矿压显现规律研究

    Study on the manifestation law of mine pressure in double-channel working face of multi-positioned thick roof plate

    • 摘要: 煤矿的复杂地质构造对工作面开采的矿压显现规律具有重要影响,严重制约着煤炭资源的安全高效回采。为研究布尔台煤矿巷道底鼓致因,揭示多位厚层顶板双巷工作面矿压显现规律及发生机理,本文构建了多位厚层顶板双巷工作面开采的物理模型和数值模型,研究了双巷工作面开采过程中覆岩位移及破断的动态变化过程,揭示了工作面开采过程中围岩垂直应力分布规律、煤柱垂直应力演化规律和围岩能量演化规律,分析了12上302辅运顺槽巷道底鼓致因。研究结果表明:12上301工作面初次来压步距为55 m,周期来压步距约8.2 m,平均岩层垮落角53.4°。覆岩下沉移动受多位厚层顶板控制,当推进60~240 m范围内,中位厚层顶板破断前各岩层下沉过程表现为离层出现-离层增大阶段,当中位厚层顶板破断后,覆岩随之整体、快速下沉。在12上301工作面推进过程中,工作面前方和临空煤柱附近的垂直应力峰值增加明显,与上覆多位厚层顶板的破断密切相关,最大应力集中系数均为3.6。临空煤柱的垂直应力在工作面后方约250 m处达到最大值,约为21.09 MPa。工作面前方和临空煤柱区域容易形成能量积聚,能量密度峰值最高达55.3 MJ/m3。12上302辅运顺槽巷道受多位厚层顶板变形破断的直接影响,临空煤柱产生了应力集中和能量积聚,最终导致巷道底鼓现象发生。本文研究可为类似条件矿井矿压治理提供理论依据。

       

      Abstract: The complex geological structure of coal mine has an important influence on the appearance law of mine pressure in working face mining, which seriously restricts the safe and efficient mining of coal resources. In order to study the causes of roadway bottom drumming in Buertai Coal Mine, and reveal the law and mechanism of mine pressure manifestation in double-channel working face of multi-positioned thick roof, this paper constructs physical and numerical models of double-channel working face mining of multi-positioned thick roof, studies the dynamic change process of overburden displacement and breakage in the process of double-channel working face mining, and reveals the law of surrounding vertical stress distribution, the law of vertical stress evolution of coal pillar, and the law of energy evolution of surrounding rock in the process of mining in working face, and analyses the law of energy evolution of 12-upper 302 auxiliary transportation roadway. It reveals the distribution law of vertical stress in the surrounding rock, the evolution law of vertical stress in the coal pillar and the evolution law of energy in the surrounding rock during the working face mining process, and analyses the cause of the bottom drum of the roadway in the auxiliary transport tunnel of 12-upper 302. The results of the study show that: the initial pressure step of 12-upper 301 working face is 55 m, the cycle pressure step is about 8.2 m, and the average rock fall angle is 53.4°. The subsidence movement of overburden rock is controlled by the roof plate of multi-positioned thick layers. When advancing within 60-240 m, the subsidence process of each rock layer before the roof plate of the median thick layer breaks down is shown as the stage of emergence of off-layers and increase of off-layers, and the overburden rock sinks rapidly as a whole after the roof plate of the median thick layer breaks down. During the advancing process of 12-upper 301 working face, the vertical stress peaks in front of the working face and in the vicinity of the adjacent coal pillar increase significantly, which is closely related to the breakage of the overlying multi-positioned thick roof plate, and the maximum stress concentration coefficient is 3.6, and the vertical stress of the adjacent coal pillar reaches the maximum value of about 21.09 MPa at about 250 m behind the working face, and the energy accumulation is easy to be formed in the area of the front of the working face and the adjacent coal pillar, and the peak energy density is up to 55.0 MPa, and the peak energy density is up to 55.0 MPa. The peak energy density reaches up to 55.3 MJ/m3. The roadway of the 12-upper 302 auxiliary transport tunnels is directly affected by the deformation and breakage of the thick roof plate, which generates stress concentration and energy accumulation in the adjacent coal pillar, and eventually leads to the occurrence of the bottom drumming phenomenon in the roadway. This study can provide theoretical basis for mine pressure management in mines with similar conditions.

       

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