Study on the Countermeasures for Disposing of the Water-rich Section of Junmachang Tunnel

Abstract

During tunnel construction, the stability of tunnel surrounding rock caused by excavation of water-rich section has always been a major problem in the project. In this paper, the influx of water in the face of the excavation of the water-rich section of the Junmachang tunnel caused a large amount of water to be unable to be constructed. The on-site sampling was carried out to test the natural and saturated water conditions and the rock mass of the excavation section under the water-rich effect was determined. The characteristics of softening of body mechanics, in view of the lithology of the surrounding rocks of the tunnel and the water inrush of groundwater in the tunnels in the water-rich section of the tunnel, a combination of the grouting reinforcement of the advancement of the small face of the tunnel face, the radial grouting reinforcement around the tunnel, and the combination of a reasonable anti-drainage system were proposed to close the groundwater treatment. The results show that the deformation of the surrounding rock in the water-rich section of the tunnel after treatment is controlled within a reasonable deformation range, and the accumulative total settlement of the dome settlement and the cumulative convergence of the clearance are less than 1/3 of the reserved deformation. The water-rich section of the Junmachang has achieved good results in the combination of advanced small-vessel grouting reinforcement, peripheral radial grouting reinforcement, and the installation of a reasonable anti-drainage system, which has certain engineering application value.