Grouting Treatment of Water and Mud Inrush in Fully Weathered Granite Tunnel: A Case Study

When mountain tunnel passes through completely weathered granite strata, water and mud inrush is easy to occur, causing casualties and economic losses. Grouting is a common and effective treatment method for water and mud inrush disaster. The current existing researches focus on theoretical analysis, numerical simulation, and laboratory test, and the researches based on the field of engineering application are few. Based on the fully weathered granite tunnel of Junchang tunnel in Guangxi, this paper studies the grouting treatment of water and mud disaster in the fully weathered granite tunnel. This paper first introduces the geological and hydrological conditions of Junchang tunnel in order to understand the causes of water inrush and mud inrush. Then, the treatment method of full-section curtain grouting is introduced. During the grouting, the combination of exploration and injection is adopted. According to different hydrological conditions, different kinds of grouting materials are adopted. After grouting is completed, Transient Electromagnetic Methods, water inflow analysis, borehole investigation, and P-Q-T method are used to evaluate the grouting effect. According to the reaction of the detection results, the weak part of grouting can be supplemented to improve the grouting quality. The results show that the curtain grouting is effective for the treatment of water-mud inrush disaster in the fully weathered granite tunnel. This study provides a reference for the treatment of water and mud inrush in other similar tunnels.