Abstract
Voids behind linings may affect the safety and performance of structures. In this paper, the applicability of the extended finite element method for simulating crack propagation was verified firstly through comparisons between numerical simulations and model tests. Moreover, the mechanical behavior of double-arch tunnels under effects of voids on the top of the middle wall was investigated numerically. Two factors, including void size and tunnel shape, were mainly investigated. The main results obtained were explored including internal forces, deformation and fracturing of the liner. The results showed that voids produced adverse effects on the liner. Internal forces on the liner experienced significant changes and the deformation of the liner increased. Besides, larger crack depth was observed at the crown and the connection between the spandrel and middle wall, indicating a significant decrease in bearing capacity of the structure compared with tunnels without voids.
Highlights
Owing to construction, materials and geological factors, most existing tunnels are suffering from lining disease, such as cracking and leaking water
Two-dimensional (2D) elastic solutions for a deep circular tunnel with a void behind the liner were presented by Yasuda et al [1]
Meguid and Dang [2] assessed the effects of voids on the internal forces through a series of simplified elastic–plastic finite element method (FEM) analyses, in which the flexibility ratio, coefficient of earth pressure at rest and void size were considered
Summary
Materials and geological factors, most existing tunnels are suffering from lining disease, such as cracking and leaking water. Meguid and Dang [2] assessed the effects of voids on the internal forces through a series of simplified elastic–plastic finite element method (FEM) analyses, in which the flexibility ratio, coefficient of earth pressure at rest and void size were considered. The model test is another effective method to study the mechanical behavior of liners. Li et al [10] studied the rock mass mechanical behavior of a large-span double-arch tunnel through the combination of model tests and numerical simulations. Most of the present research about the issue only study a single tunnel; it is not known that how voids affect the mechanical behavior of liners in double-arch tunnels. A model test and numerical simulation were carried out respectively to investigate the mechanical behavior of asymmetrical double-arch tunnels under the effects of voids. Results obtained from two methods were compared to verify the applicability of the extended finite element method for simulating crack propagation
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