| Abstrakt: |
It is very easy to encounter the phenomenon of water and mud gushing during construction and excavation of tunnel through karst area. How to choose appropriate anti-seepage measures to reduce the seepage flow of tunnel has always been a hot issue. In this paper, a three-dimensional finite element model of complex strata in karst area is established based on a water diversion project . Three anti-seepage measures, namely back-filling concrete on the roof of the tunnel, grouting ring around the tunnel and concrete cutoff wall, are mainly considered. The change law of pore water pressure and seepage flow of the tunnel during tunnel excavation is studied, and the influence of permeability coefficient of the cutoff wall and grouting ring on seepage characteristics is analyzed. The results show that the concrete cutoff wall has a great influence on the distribution of pore water pressure in the tunnel, the water level between the cutoff walls decreases obviously, and the grouting ring around the tunnel has the greatest influence on the seepage flow of the tunnel, and the quality of the grouting ring should be ensured during construction. The pore water pressure increases with the increase of the horizontal distance from the tunnel center, and increases first and then decreases with the increase of the vertical distance from the tunnel center. With the increase of the permeability coefficient of the grouting ring or the cutoff wall, the pore pressure growth rate in the area of the grouting ring or the wall decreases gradually, and the seepage flow of the tunnel increases continuously. [ABSTRACT FROM AUTHOR] |
