基于非结构有限元的电阻率超前探测中旁侧异常影响特征研究

A study on the influence of side anomalies in resistivity-based advance detection based on an unstructured finite element method

为了进一步探究旁侧异常体在巷道电阻率超前探测中的影响规律,提高探测精度,采用基于对偶加权后验误差估计的自适应非结构有限元法进行三维正演研究。首先通过无限大垂直板状体模型验证了该方法在超前探测模拟中的适用性和准确性,建立无旁侧异常体模型模拟巷道中的超前探测响应;然后分别对高低阻旁侧异常体的方位、与巷道h和掌子面的距离、巷道大小、不同供电和接收方式以及在多层介质中对超前探测的影响进行了数值模拟。结果表明:巷道前方异常体的实际位置可由异常曲线极值推断出;高低阻旁侧异常体的响应总体上不会掩盖巷道前方的异常响应特征,但会使对应范围内的异常曲线出现凸形或凹形畸变,畸变位置与实际位置相符合;巷道空腔的存在加强了底板异常响应,不同巷道大小对顶板异常影响不同,总体上不会影响巷道前方的异常响应;多层地层中,异常响应曲线仍能反映出旁侧异常体的实际位置,巷道前方的异常响应特征是否会被掩盖要视各层电阻率大小情况而定。干扰异常的辨别需要结合实际进一步开展研究。

To further explore the influence patterns of side anomalies in resistivity-based advance detection for roadways and to improve the detection accuracy,this study conducted three-dimensional forward modeling using an adaptive unstructured finite element method based on dual weighted posteriori error estimation.First,this study verified the applicability and accuracy of this method in the simula-tion of advanced detection using an infinite vertical plate model.Then,it established a model without considering side anomalies to sim-ulate the advance detection response in roadways.Then,it conducted numerical simulations of high-and low-resistivity side anomalies'directions,the distances from side anomalies to roadways and mining faces,roadway sizes,power supply and reception ways,and the in-fluence of side anomalies on advance detection in multi-layer media.Finally,this study analyzed the morphological characteristics of ap-parent resistivity anomaly curves.The results are as follows:(1)The actual positions of anomalies in front of roadways can be inferred from the extreme values of anomaly curves;(2)The responses of high-and low-resistivity side anomalies generally do not mask the re-sponse characteristics of anomalies in front of roadways.However,they can distort the anomaly curves in the corresponding range by making them convex or concave,with the distortion positions consistent with the actual positions of anomalies;(3)The presence of road-way cavities enhances the responses of anomalies on roadway floors.Although different roadway sizes impose different effects on anoma-lies on roadway rooves,they do not affect the responses of anomalies in front of roadways in general;(4)In multi-layer strata,anomaly response curves can still reflect the actual positions of side anomalies.Whether the response characteristics of anomalies in front of road-ways are masked depends on the resistivity of each layer;(5)The identification of interference anomalies requires further research in combination with actual conditions.