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回采巷道底鼓演化过程的分布式光纤实测研究

Distributed optical fiber measurement of floor heave evolution in mining roadway

  • 摘要: 随着煤矿开采的深部化和开采设备的大型化,回采巷道底鼓成为制约工作面高效、安全回采的重要问题,揭示回采巷道底鼓的发生规律对巷道底板稳定性控制具有重要意义。在分析回采巷道底板变形破坏特征的基础上,结合巷道底鼓关键特征研究了分布式光纤应变表征方法,并通过钻孔布设分布式传感光缆,以煤矿现场大量实测数据为依据,对工作面回采过程中回采巷道底鼓的发生进行了系统分析。研究结果表明:分布式光纤以一个正应变峰值和一个负应变峰值分别对应底板岩层的离层和挤压的非协调挠曲变形特征,以光纤局部范围受拉对应底板岩层的破碎和挤压膨胀变形特征,破碎特征区光纤的应变增量、增速反映了破碎岩块之间的挤压剧烈程度。将回采巷道底鼓演化过程分为扰动、破坏、卸压隆起3个阶段,指出每个阶段底板岩层破坏特征,确立了各阶段破碎区分布式光纤应变特征值关键信息。研究所得结论为实现巷道围岩大范围分布式光纤监测提供新的思路,对回采巷道底鼓控制具有指导意义。

     

    Abstract: With the deepening of coal mining and the upsizing of mining equipment, the floor heave of the mining roadway has become an important problem that restricts the efficient and safe mining of the working face. It is of great significance to reveal the occurrence law of floor heave of the mining roadway for the stability control of the roadway floor. Based on the analysis of the deformation and failure characteristics of the mining roadway floor, com-bined with the key characteristics of the roadway floor heave, this paper studies the distributed optical fiber strain characterization method, and embeds the distributed sensing optical cable into the roadway floor through the borehole. Based on a large number of field measured data in the coal mine, the oc-currence of the roadway floor heave in the mining process of the working face is systematically analyzed. The results show that the distributed optical fiber has a positive strain peak and a negative strain peak respectively corresponding to the uncoordinated bending deformation characteristics of delamination and extrusion of the floor rock, and the local tension of the optical fiber corresponds to the crushing and extrusion expansion deformation characteristics of the floor rock. The strain value and strain growth rate of the optical fiber in the crushing characteristic area reflect the intensity of extrusion between the broken rock blocks. The evolution process of mining roadway floor heave is divided into three stages: disturbance, failure and relief uplift. The failure characteristics of floor strata in each stage are pointed out, and the key information of distributed optical fiber strain characteristic values in the crushing area in each stage is established. The conclusion of the study provides a new idea for the realization of large-scale distributed optical fiber monitoring of roadway surrounding rock, and has guiding significance for the floor heave control of mining roadway.

     

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