Abstract:
Mine audio frequency electrical resistivity perspective method is one of the main methods of water disaster monitoring in coal working face. However, its monitoring electrodes are easy to rust, leading to the decline of monitoring data quality, which adversely affects the imaging and interpretation of monitoring results. In this paper, study on physical simulation of mine water disaster monitoring by audio frequency electrical resistivity perspective method in water tank was carried out. A physical model with a similarity size ratio of 1∶250 was established to simulate the dynamic rising process of the floor water. The influence characteristics of electrode rusting on the monitoring data were analyzed by comparing the physical simulation results with the numerical simulation results. The electrode consistency correction method was used to suppress the influence of electrode rusting. Three-dimensional electrical resistivity inversion and imaging were carried out to verify the effectiveness of the electrode consistency correction method. The results of physical simulation and numerical simulation show that, shallow small-scale anomaly and deep anomaly (within depth of 70 m) will cause the maximum value of the receiving curves to decrease slightly near their centers; with the buried depth of the deep anomaly rising gradually, the receiving curves intersect at the center of the deep anomaly and show an increasingly obvious double hump shapes in a whole. Electrode rusting may cause zigzag distortion or overall deviation of the receiving curves. The acquisition error caused by electrode rusting may cover up the anomalous responses of shallow small-scale anomalies and deep anomalies, and cause false anomalies in imaging results, which adversely affects the interpretation of monitoring results. Electrode consistency correction method is used to solve the problem. By sorting and smoothing the monitoring data in the order of common transmitting points and common receiving points respectively, the acquisition error caused by electrode rusting is eliminated. After electrode consistency correction, false anomalies in imaging results are suppressed and imaging effect is also improved. In addition, the receiving curves of physical simulation are lower on the left and higher on the right, causing the positions of anomalies in the imaging results shifting to the right, which needs further experiments to explore the causes of the phenomenon.