Anti-Plane Dynamics Analysis of a Circular Lined Tunnel in the Ground under Covering Layer

Jing Guo,Fuqing Chu,Hui Qi,Guohui Wu,Yang Zhang

doi:10.3390/sym13020246

Abstract

Wave diffusion in the composite soil layer with the lined tunnel structure is often encountered in the field of seismic engineering. The wave function expansion method is an effective method for solving the wave diffusion problem. In this paper, the wave function expansion method is used to present a semi-analytical solution to the shear horizontal (SH) wave scattering problem of a circular lined tunnel under the covering soil layer. Considering the existence of the covering soil layer, the great arc assumption (that is, the curved boundary instead of the straight-line boundary) is used to construct the wavefield in the composite soil layer. Based on the wave field and boundary conditions, an infinite linear equation system is established by adding the application of complex variable functions. The finite term is intercepted and solved, and the accuracy of the solution is analyzed. Although truncation is inevitable, due to the Bessel function has better convergence, a smaller truncation coefficient can achieve mechanical accuracy. Based on numerical examples, the influence of SH wave incident frequency, soil parameters, and lining thickness on the dynamic stress concentration factor of lining is analyzed. Compared with the SH wave scattering problem by lining in a single medium half-space, due to the existence of the cover layer and the influence of its stiffness, the dynamic stress of the lining can be increased or inhibited. In addition, the lining thickness has obvious different effects on the dynamic stress concentration coefficient of the inner and outer walls of different materials.

Highlights

In recent decades, while the use of underground space by humans has increased, underground tunnels have been used extensively in infrastructure
The stresses at or near the boundary of the lining can be significantly phantom under the disturbance of shear horizontal (SH) waves
For this kind of problem, the dynamic stress concentration factor is usually used to reflect the degree of stress concentration

Summary

Introduction

While the use of underground space by humans has increased, underground tunnels have been used extensively in infrastructure. The researchers studied a series of scattering problems using the wave function expansion method based on the large arc assumption method [17,18,19]. The successful application of the complex variable function theory to the problems related to elastic wave scattering and dynamic stress concentration in any hole in the whole space makes the great arc assumption method easier to use [20,21,22]. The wave function expansion method combined with the great arc assumption method is an ideal analytical method to solve the problem of elastic wave scattering by tunnels in composite soil layers. This paper further investigates the dynamic stress concentration in circular tunnels under SH-wave interference in the soil below the covering soil layer

Model and Analysis

The circular lined tunnel disturbedby byshear shearhorizontal horizontal

Results and Discussion

Figures and

Variation around outer outer surface for geological geological combina*

Conclusions