工作面采动破坏过程电阻率动态响应特征研究

Study on dynamic response characteristics of resistivity in mining failure process of working face

  • 摘要: 矿井电阻率法在采煤工作面水害隐患监测中发挥着重要作用,但工作面采动破坏过程的异常响应会对底板水害隐患的识别形成较大干扰。为了提高矿井电阻率法对采煤工作面底板水害隐患监测的解释精度,同步考虑覆岩破坏和底板破坏的影响,建立工作面采动破坏过程动态地电模型,通过矿井电阻率法三维数值模拟和反演成像,分别进行顶板监测和底板监测,分析采动破坏过程的电阻率动态响应特征,识别和提取底板水害隐患的电阻率响应特征。分析结果表明:采动破坏过程形成的电阻率异常区随回采工作面推进向前移动,在超前支撑压力的作用范围内会出现相对低阻异常,在采空区范围内会出现相对高阻异常;工作面固定位置的电阻率响应在回采过程中会经历先降低、后升高、再降低的过程,该过程与工作面回采过程中顶底板经历的周期性应力变化和破坏过程基本一致;底板水害隐患的低阻异常响应强度与其相对回采工作面的位置有关,当底板水害隐患的展布范围与采空区范围有所重合时,采空区的高阻异常响应会削弱底板水害隐患的低阻异常响应;当底板水害隐患的展布范围与超前支撑压力影响区范围有所重合时,二者的低阻异常响应会叠加在一起,使低阻异常响应得到一定幅度的增强;针对底板水害隐患进行纯异常提取后,可以消除采动破坏过程的影响,不同位置的底板水害隐患其纯异常响应强度基本一致,其垂向影响范围均大于采动破坏的垂向影响范围。

     

    Abstract: The mine resistivity method plays an important role in monitoring hidden danger of water hazards in coal working face. However, the abnormal response of mining failure process of coal working face will interfere with the identification of hidden danger of floor water hazards. In order to improve the interpretation precision of the mine resistivity method for monitoring hidden danger of floor water hazard in coal working face, simultaneously considering the influence of overburden failure and floor failure, a dynamic geoelectric model of the mining failure process in coal working face is established. The roof monitoring and floor monitoring are respectively carried out through three-dimensional numerical simulation and inversion imaging of mine resistivity method. The dynamic response characteristics of resistivity in the mining failure process are analyzed. The resistivity response characteristics of floor water hazard are identified and extracted. The analysis results show that the resistivity anomaly area formed in the process of mining failure moves forward with the advancing of the working face. There will be relatively low resistivity anomaly in the action range of the advance support pressure, and relatively high resistivity anomaly in the goaf area. The resistivity response at the fixed position of the working face will experience a process of first decreasing, then increasing, and then decreasing in the mining process. This process is basically consistent with the periodic stress change and failure process of the roof and floor in the mining process of the working face. The low resistance abnormal response intensity of floor water hazard is related to its position relative to the working face. When the distribution range of floor water hazard overlaps with that of goaf, the high resistance abnormal response of goaf will weaken the low resistance abnormal response of floor water hazard. When the distribution range of floor water hazard danger overlaps with the area affected by the advance support pressure, the low resistance abnormal response of the two will be superimposed together. The low resistance abnormal response can be enhanced to a certain extent. The influence of the mining damage process can be eliminated after the pure anomaly extraction of the hidden danger of floor water hazard. The pure abnormal response intensity of floor water hazards at different positions is basically the same, and their vertical influence scope is larger than that of mining damage.

     

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