Anisotropic effect of surrounding rocks using the resistivity method in tunnel prediction

Abstract

In predicting water-bearing disaster structures in tunnels, complex geological conditions can pose significant risks to underground construction. To enhance data interpretation accuracy, this study presents a tunnel prediction method that accounts for the anisotropic effect of surrounding rocks using an unstructured finite element resistivity approach. A classic whole-space model has validated the effectiveness of the algorithm. We conducted simulations of a fault structure under the anisotropic surrounding rocks. The results indicated that increasing the anisotropy coefficient and Euler angle resulted in a greater offset distance of the minimum apparent resistivity. Compared with the isotropic model, the predicted distance of the anisotropic model was found to be greater. To address the adverse effects of tunnel and rock anisotropy, a ratio-based method was proposed in data processing, which has been proven to be effective. Next, we simulated a large number of models using the Monte Carlo method and found that anisotropic Euler angles caused significant deviations. Furthermore, our findings revealed that the prediction results were more reliable than those in previous literature. Finally, we applied this method to a real-world case of tunnel prediction, and the predicted results closely matched the true distance. This study will provide important insights for the practical application of tunnel prediction in complex geological environments.