Deformation Characteristics of the Surrounding Rock of a Six-Lane Multiarch Tunnel under Different Excavation Conditions

Lina Luo,Haibo Hu,Gang Lei,Bingxiang Yuan

doi:10.1155/2021/7570359

Abstract

Highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions. Therefore, it is necessary to explore the deformation characteristics of the surrounding rock of a six-lane multiarch tunnel under different excavation conditions. Using the three-dimensional indoor model test and finite element analysis, this paper studies the dynamic mechanical behavior of a six-lane construction, reveals the whole process of the surrounding rock deformation process of class II surrounding rock under different excavation conditions, and puts forward the best construction and excavation method. The results show that the maximum displacement rate of excavation scheme III is the largest, and the maximum displacement rate of excavation scheme I is basically the same as that of excavation scheme II. Therefore, in terms of controlling the displacement rate of the surrounding rock, the effect of excavation scheme I is basically the same as that of excavation scheme II, while that of excavation scheme III is poor. In terms of construction technology, scheme II is simpler than scheme I and can ensure the integrity of the secondary lining. Therefore, in class II surrounding rock of the supporting project, it is recommended to adopt scheme II for construction.

Highlights

In recent years, civil engineering has developed rapidly [1,2,3,4,5,6]
Using the similar model test method to study the construction mechanical form of a mountain highway tunnel, take a square plane twice the tunnel span and a research unit including the tunnel as the research object. ere are two common methods to simulate tunnel excavation. e first is the hollow body loading scheme
E surrounding rock of the six-lane multiarch tunnel is greatly disturbed by mutual construction, and the shape of displacement duration curve is complex because of the influence of this construction disturbance

Summary

Introduction

Civil engineering has developed rapidly [1,2,3,4,5,6]. As an important structural form of civil engineering, highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions [7,8,9]. e tunnel scheme can shorten the mileage, improve the line shape, and protect the environment. Because of the diversity and complexity of the geological conditions of the tunnel surrounding rock and the uncertainty of the stress of the tunnel support structure, the design and construction of the tunnel engineering structure are still in a semitheoretical and semiempirical state, and the theoretical calculation is mainly used as qualitative analysis [12,13,14,15,16]. E large excavation span of a multiarch tunnel, coupled with many factors, such as the interaction caused by excavation, multiple disturbances of the surrounding rock, and asynchronous construction between the support and lining during the construction of the two main tunnels, makes its stress conditions extremely complex. Erefore, for a multiarch tunnel, on-site monitoring, measurement, and back analysis are important means for many scholars to timely grasp the dynamic changes of surrounding rock and the stress of supporting structure, especially under complex geological conditions. Miura et al comprehensively measured and analyzed the new Tomei Meishin on the TokyoKobe expressway and compared it with the four-lane tunnel

Methods

Results

Conclusion