基于光纤光栅传感技术的深部巷道围岩状态精准表征

    Precise characterization of deep roadway surrounding rock status utilizing Fiber Bragg Grating sensing technology

    • 摘要: 巷道围岩的变形和破坏是制约煤炭安全、高效生产的主要因素之一,精准的巷道围岩变形和破坏监测对确保煤炭资源安全开采具有重要意义,但传统监测技术难以满足目前巷道围岩精确监测的要求。为探索巷道围岩监测新的方法,针对采动影响下深部巷道围岩变形精准表征难题,结合淮北矿区杨柳煤矿1034工作面回采巷道工程地质条件,利用准分布式光纤光栅(FBG)传感技术,开展工作面回采过程中的巷道深浅部围岩动态变形特征实验研究。研究结果表明:回风巷两帮光纤应变变化存在较大差异,实体煤侧沿水平方向发生拉伸变形,煤柱侧因采动影响局部产生压缩变形且实体煤侧变形量是煤柱侧的两倍;随着工作面逐渐靠近监测位置,巷道围岩变形预演剧烈。工作面回采超前支承压力对于巷道围岩深部的影响越来越弱,围岩产生的应变也越来越小,应变峰值集中在孔深3~4 m;光纤光栅的应变分布与地层岩性相互对应,在弹性模量较小、岩性较软的泥岩中,光纤处于拉伸状态应变值较大,在弹性模量较大、硬度较高的细砂岩中,光纤处于压缩状态应变值较小。准分布式光纤传感技术能够实现在工作面回采过程中巷道围岩变形全过程监测,为深部巷道变形破坏的精准表征提供依据。研究成果可为后续巷道围岩状态感知提供参考与借鉴。

       

      Abstract: The deformation and failure of roadway surrounding rocks are key factors limiting the safe and efficient production of coal. Accurate monitoring of roadway surrounding rock deformation and failure is crucial for ensuring the safe extraction of coal resources. However, traditional monitoring techniques struggle to meet the current demands for precise monitoring of roadway surrounding rocks. To explore new methods for monitoring roadway surrounding rocks, this paper focuses on the challenge of precise characterization of the deformation of deep roadway surrounding rocks under mining influence. The paper is conducted in the 1034 working face of the Yangliu Coal Mine in the Huaibei Mining Area, utilizing quasi-distributed Fiber Bragg Grating (FBG) sensing technology to investigate the dynamic deformation characteristics of the surrounding rock in both deep and shallow parts of the roadway during the mining process. The results indicate that there are significant differences in the strain changes measured by optical fibers on the two sides of the return airway. Tensile deformation occurs in the coal side along the horizontal direction, while compression deformation occurs locally on the coal pillar side due to mining influence, with the deformation amount in the coal side being twice that of the coal pillar side. As the working face approaches the monitoring position, the deformation of the roadway surrounding rock becomes more severe. The influence of the advanced support pressure on the deep part of the roadway surrounding rock diminishes, and the strain generated by the surrounding rock decreases accordingly, with the strain peak values concentrated at a depth of 3 to 4 meters. The strain distribution measured by the FBG corresponds to the rock layer’s lithology. In mudstones with lower elastic modulus and softer lithology, the optical fibers experience tensile strain with higher values, while in fine sandstones with higher elastic modulus and hardness, the optical fibers experience compressive strain with lower values. The quasi-distributed FBG sensing technology enables comprehensive monitoring of the deformation process of roadway surrounding rocks during the mining of the working face, providing a basis for the accurate characterization of deep roadway deformation and failure. The findings offer valuable references and insights for subsequent perception of roadway surrounding rock conditions.

       

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