Structural analysis of pressure tunnel of hydropower station based on extended finite element method

Abstract

The lining of the tunnel generally cracks under the action of internal water pressure, which will threaten structural safety. It is difficult to simulate the discontinuity problem like cracking by the traditional finite element method. In order to study the influence of different tunnel lining structure types on structural safety and to find the better structure type, two types of tunnel lining models (circular and horseshoe) are simulated in this paper. The extended finite element method is used to calculate the stress distribution, crack distribution law, and expansion process of tunnel lining under different conditions. The results show that the lining cracks penetrate the horseshoe section, but not the round section under the same load and lining thickness. By improving the lining of the horseshoe section and analyzing it again, the results showed that the crack length was shortened, and the structural safety was improved. The study can provide a reference for the structural type selection of pressurized tunnel lining.