岳建华,滕小振,胡双贵,等. 基于孔间直流电透视的煤层底板采动破坏电阻率时移变化规律与机理[J]. 煤炭学报,2024,49(1):601−615. DOI: 10.13225/j.cnki.jccs.YH23.1590
引用本文: 岳建华,滕小振,胡双贵,等. 基于孔间直流电透视的煤层底板采动破坏电阻率时移变化规律与机理[J]. 煤炭学报,2024,49(1):601−615. DOI: 10.13225/j.cnki.jccs.YH23.1590
YUE Jianhua,TENG Xiaozhen,HU Shuanggui,et al. Time-lapse change pattern and mechanism of resistivity of coal seam floor mining damage based on inter-hole DC perspective[J]. Journal of China Coal Society,2024,49(1):601−615. DOI: 10.13225/j.cnki.jccs.YH23.1590
Citation: YUE Jianhua,TENG Xiaozhen,HU Shuanggui,et al. Time-lapse change pattern and mechanism of resistivity of coal seam floor mining damage based on inter-hole DC perspective[J]. Journal of China Coal Society,2024,49(1):601−615. DOI: 10.13225/j.cnki.jccs.YH23.1590

基于孔间直流电透视的煤层底板采动破坏电阻率时移变化规律与机理

Time-lapse change pattern and mechanism of resistivity of coal seam floor mining damage based on inter-hole DC perspective

  • 摘要: 煤层采动过程中,底板应力状态的改变会产生变形与破坏,而不同煤层采动过程中底板破坏具有一定的规律。目前基于直流电阻率法的煤层底板水害监测主要集中于底板变形与破坏的电阻率响应特征上。为了研究工作面回采过程中煤层底板的电性时移变化特征,采用孔间直流电透视观测系统和时移电阻率反射系数法,通过数值模拟和现场试验揭示了煤层底板采动破坏电阻率时移规律。首先,针对典型地电模型,对比单独反演和时移电阻率变化率的结果,验证了孔间直流电透视时移方法的可靠性。然后,针对煤层底板采动破坏,分析了采动过程中底板承压水导升与底板破坏带的电性响应规律与特征,并讨论了时移电阻率反射系数确定煤层底板破坏深度的可行性,为野外施工提供理论依据。最后,通过现场监测试验,获得工作面回采过程中煤层底板的电性变化特征,并采用时移电阻率反射系数R确定了工作面底板岩层的破坏深度为15 m。结果表明:利用孔间直流电透视法获得的煤层底板采动破坏电阻率时移特征可在一定程度上消除了监测数据中的地层因素和随机噪声影响,且时移电阻率反射系数可用来确定煤层底板破坏深度。该方法将探测目标从单一的研究地质异常转换到对煤层采动过程中工作面底板破坏的全生命周期动态监测,进而实现了工作面底板结构破坏的精细刻画。

     

    Abstract: During the coal mining process, the change in the floor stress state of coal seam will produce deformation and failure. The seam floor failure in different coal mining processes has a certain law. At present, the water disaster monitoring of coal seam floors based on the DC resistivity method mainly focuses on the resistivity response characteristics of floor deformation and damage. To investigate the temporal changes in the electrical properties of the coal seam floor during mining, this study employs the inter-hole DC perspective observation system and the time-lapse resistivity reflection coefficient method. Through numerical simulation and field tests, the study uncovers the temporal variation law of the resistivity of coal seam floor induced by mining activities. First, this paper compares the results of individual inversion and time-lapse resistivity change rates for a typical geoelectric model to validate the reliability of the inter-hole DC perspective time-lapse method. Next, considering the mining-induced damage to the coal seam floor, this paper analyzes the electrical response patterns and charac-teristics of the rise of confined water and the damage zone in the floor during the mining process. It also discusses the feasibility of using a time-lapse resistivity reflection coefficient to assess the depth of coal seam floor damage, offering a theoretical basis for field construction. Finally, , the on-site monitoring tests reveal the electrical change characteristics of coal seam floor during the coal mining process. The time-lapse resistivity reflection coefficient R is utilized to determine the damage depth of the rock layer of the working face floor, which is found to be 15 m. The study results demonstrate that the time-lapse characteristics of the resistivity of coal seam floor mining damage obtained by the inter-hole DC perspective method can mitigate the influence of formation factors and random noise in the monitoring data to a certain extent. Additionally, the time-lapse resistivity reflection coefficient can be utilized to determine the depth of coal seam floor failure. This method transforms the detection target from the single study of geological anomalies to the full life cycle dynamic monitoring of the floor damage of the working face in the process of coal mining and then realizes the detailed depiction of structural damage to the working surface floor.

     

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