Seepage Behavior of Underwater Tunnels in Stratum with Inclined Surface: Insights from Numerical Analysis

Abstract

This paper is to investigate the seepage behavior of underwater tunnel with inclined boundary at the contact between water body and underwater stratum. Extensive finite element analyses using COMSOL are performed considering various magnitudes of inclination degree of underwater soil surface. The rationality of the numerical analysis method is demonstrated via comparing with analytical solutions. It is found that the inclined boundary has a significant impact on the seepage field of underwater tunnel. The hydraulic head distribution, streamline evolution, velocity and other aspects are comprehensively analyzed, and relevant conclusions are drawn. The streamlines in waters are not vertically downward, but presents a certain acute angle distribution with the stratum direction. And the interface angle toward the depth is larger. Streamlines will also become denser. The streamline flows into the tunnel from all directions. And the attenuation speed of water head in the lower part of tunnel is less than that in the upper part. Thereby serving the optimal design and construction of practical projects.