An analytical method of continuous upper bound limit analysis for the stability of shallow shield tunnels in cohesive-frictional soils
Autor: | Yanyong Xiang, Wenjie Song |
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Rok vydání: | 2020 |
Předmět: |
Optimization problem
General Mathematics General Engineering Particle swarm optimization Mechanics Slip (materials science) Dissipation 01 natural sciences Upper and lower bounds Finite element method Physics::Geophysics 010305 fluids & plasmas 010101 applied mathematics Limit analysis 0103 physical sciences Displacement field 0101 mathematics Geology |
Zdroj: | Journal of Engineering Mathematics. 122:101-116 |
ISSN: | 1573-2703 0022-0833 |
Popis: | For stability analysis of shallow shield tunnels in cohesive-frictional (clayey–sandy) soils, an analytical method of continuous upper bound limit analysis is developed to determine the most critical slip line position and the minimum required tunnel support pressure. The ground displacement field due to composite volume loss is calculated using a complex variable solution, and the optimization problem is solved by employing the particle swarm optimization technique. Energy dissipation at the potential slip boundary, which is determined through a system of tracking schemes, and in the corresponding potential plastic zone is taken into account. Example calculations are carried out to verify the proposed method via finite element simulations and comparisons with solutions from existing methods, and to study the effects of soil strength properties and tunnel size and depth. The results show that both the internal friction and the cohesion of the surrounding soil may help reduce the range of the potential collapse zone and the magnitude of the necessary support pressure. This study represents the first attempt to deal with cohesive-frictional soils via an analytical and continuous approach, and the developed method can be extended for various tunnel and other geotechnical stability problems involving cohesive-frictional soils. |
Databáze: | OpenAIRE |
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