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矿用高分子薄喷层护表支护试验研究

Experimental study on surface protection support of mine polymer thin spray layer

  • 摘要: 薄喷层广泛应用于矿山的密闭工程,具有承载能力的薄喷层是地下煤矿巷道支护中取代金属网的新方法,具有掘进速度快、自动化程度高、适用范围广的优点。首先基于TSL在软岩巷道的变形过程,对TSL的支护作用理论进行分析,认为TSL与表面围岩产生连锁效应,黏结层对深部岩体变形产生约束作用。围岩大变形条件下形成TSL薄壳结构,产生支护作用。基于煤矿巷道现场实际制作大型型煤煤柱试样,使用一种新研发的高分子TSL材料开展试验研究,对比分析了不同护表方式的支护效果。结果显示:TSL比菱形网的约束作用更强,试样应力峰值提高了28.3%。同时,TSL试件残余强度更高,系统能量耗散增加了44.1%。巷道大变形阶段TSL与约束岩体形成薄壳结构,本文首次对不同岩体TSL壳结构的支护效果进行了试验研究。结果显示:TSL壳结构通过自身承载压应力降低表面围岩变形,褐煤和砂岩试样承载能力分别增加了44.6%和20.4%,能量散耗增加约2倍。采用数值计算方法,分析了TSL的煤柱约束作用和薄壳支护试验过程中自身的承载状态和对围岩变形的控制机制,并与试验观测结果进行了比对。研究为TSL支护工程实践提供理论依据,为煤矿巷道TSL支护效果预测提供试验研究方法。

     

    Abstract: Thin shotcrete layer is widely used in mine sealing engineering. Thin shotcrete layer with bearing capacity is a new method to replace metal mesh in underground coal mine roadway support. It has the advantages of fast tunneling speed, high degree of automation and wide application range. Firstly, based on the deformation process of TSL in soft rock roadway, the supporting theory of TSL is analyzed. It is considered that TSL has a chain effect with surface surrounding rock, and the bonding layer has a restraining effect on the deformation of deep rock mass. Under the condition of large deformation of surrounding rock, TSL thin shell structure is formed to produce supporting effect. Based on the actual production of large-scale coal pillar samples in coal mine roadways, an experimental study was carried out using a newly developed polymer TSL material, and the supporting effects of different surface protection methods were compared and analyzed. The results show that the constraint effect of TSL is stronger than that of diamond mesh, and the peak stress of the sample is increased by 28.3%. At the same time, the residual strength of TSL specimens is higher, and the energy dissipation of the system increases by 44.1%. In the large deformation stage of roadway, TSL and constrained rock mass form a thin shell structure. In this paper, the support effect of TSL shell structure in different rock mass is studied experimentally for the first time. The results show that the TSL shell structure reduces the deformation of the surface surrounding rock through its own bearing compressive stress. The bearing capacity of lignite and sandstone samples increases by 44.6% and 20.4%, respectively, and the energy dissipation increases by about 2 times. The numerical calculation method is used to analyze the coal pillar constraint effect of TSL and the bearing state and the control mechanism of surrounding rock deformation in the process of thin shell support experiment, and compared with the experimental observation. This study provides a theoretical basis for the practice of TSL support engineering and an experimental research method for the prediction of TSL support effect in coal mine roadway.

     

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