华北型煤田煤层底板岩溶水害防治的主要技术手段是对含水岩层进行注浆改造，目前注浆效果检测的手段主要是对注浆前后岩性特征进行分析，缺少对注浆全过程的跟踪动态监测，很难对注浆效果进行准确评价。针对上述问题，引入孔间电阻率监测系统对注浆改造岩层的电阻率变化特征进行全过程监测，以实现浆液扩散范围的精准探测。首先，采用改进电极和线缆装置将电阻率监测系统置于煤层底板长定向钻孔内，实现孔间的电阻率监测；然后，构建浆液扩散的地质模型，采用三维电阻率反演对模拟数据进行处理解释；最后，在煤矿井下注浆层位开展注浆全过程的孔间电阻率监测工程试验。模拟结果表明：孔间电阻率监测能识别浆液异常的扩散范围，根据电阻率随时间的变化趋势可推测浆液扩散范围，随着浆液逐渐扩散，异常区范围逐渐变大，异常强度逐渐增强。工程试验结果表明：通过钻孔将电阻率监测系统布置于注浆层位进行动态监测，监测数据经三维反演成像后能成功捕捉到浆液扩散导致的注浆层位电阻率变化特征，为煤矿注浆效果检测提供一种可行的技术方案。

The main technical means for preventing and controlling karst water damage in the coal seam floor of North China type coal fields are grouting transformation of the water-bearing rock layer. Currently, the main method for testing the grouting effect is to analyze the lithological features before and after grouting. There is a lack of tracking and dynamic monitoring of the entire grouting process, making it difficult to accurately evaluate the grouting effect. In order to solve the above problems, an inter hole resistivity monitoring system is introduced to monitor the entire process of resistivity changes in grouting transformed rock layers, in order to achieve precise detection of the slurry diffusion range. Firstly, an improved electrode and cable device is used to place the resistivity monitoring system in a long directional borehole on the coal seam floor, achieving resistivity monitoring between boreholes. Secondly, a geological model of slurry diffusion is constructed, and the simulated data is processed and interpreted using three-dimensional resistivity inversion. Finally, engineering tests are conducted on the inter hole resistivity monitoring of the entire grouting process at the injection layer underground in the coal mine. The simulation results indicate that inter hole resistivity monitoring can identify the diffusion range of slurry anomalies. Based on the trend of resistivity changes over time, the diffusion range of slurry can be inferred. As the slurry gradually diffuses, the range of anomalous areas gradually increases and the intensity of anomalies gradually increases. The engineering test results show that the resistivity monitoring system is arranged on the grouting layer through drilling for dynamic monitoring. After three-dimensional inversion imaging of the monitoring data, the features of resistivity changes in the grouting layer caused by slurry diffusion can be successfully captured. It provides a feasible technical solution for detecting the grouting effect in coal mines.