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煤矿多孔骨料注浆截流试验机理研究

Research on the experimental mechanism of grouting and interception of porous aggregate in coal mine

  • 摘要: 我国煤矿水害事故频发,利用浆液封堵巷道中的多孔骨料是建造堵水墙实现截流堵水的有效方法。现场注浆过程难控制、不易观察,为了更好地揭示注浆结石体的形成,设计了一套可视化浆液-骨料渗透扩散与封堵试验装置,模拟不同工况下灌注多孔骨料建造堵水墙的过程。正交试验下研究了不同骨料粒径、浆液水灰比与巷道倾角的可注性与封堵巷道的难易程度,分析了浆液在多孔骨料中的运移特征。结果表明:动水注浆过程中,沉积区域首先在巷道底部开始出现,接着向两侧扩展,然后向上发育,直至充满整个巷道;注浆截流效果受控于多因素影响,浆液水泥体积分数为33%、骨料粒径范围在1~2 mm的下行巷道时更容易充实骨料空隙;根据浆液在骨料中不同的流动状态,可以将注浆截流过程划分为三个阶段:填充阶段、沉积阶段与加压阶段;注浆截流本质是浆液中不稳定的水泥颗粒在充填骨料空隙中经离析、水化、滤过、沉淀等一系列物理化学反应转化为结石体实现阻水过程。研究成果对截流骨料选型和浆液配比具有借鉴价值,为巷道突水后快速封堵提供科学的参考依据。

     

    Abstract: In China, coal mine water disasters occur frequently. Using slurry to block the porous aggregate in the roadway is an effective method to build a water blocking wall to achieve water closure. The on-site grouting process is difficult to control and observe. In order to better reveal the formation of grouting stone body, a set of visual grout aggregate penetration diffusion and plugging test device is designed to simulate the process of constructing water plugging wall by pouring porous aggregate under different working conditions. Under the orthogonal test, the inject ability of different aggregate size, slurry water cement ratio and roadway dip angle and the difficulty of plugging the roadway are studied, and the movement characteristics of slurry in porous aggregate are analyzed. The results show that in the process of hydrodynamic grouting, the deposition area first appears at the bottom of the roadway, then expands to both sides, and then develops upward until it fills the entire roadway; The effect of grouting closure is controlled by many factors. When the volume fraction of grout cement is 33% and the size range of aggregate is 1-2mm, the downward roadway is easier to fill the aggregate gap; According to different flow states of grout in aggregate, the process of grouting closure can be divided into three stages: filling stage, sedimentation stage and pressurization stage; The essence of grouting closure is a process in which unstable cement particles in the grout are transformed into stone bodies through a series of physical and chemical reactions such as segregation, hydration, filtration, sedimentation, etc. in the filled aggregate voids to achieve water blocking. The research results have a reference value for the selection of river closure aggregate and slurry ratio, and provide a scientific reference for rapid plugging after water inrush in the roadway.

     

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