Study on the Generalized Displacement Boundary and Its Analytical Prediction for Ground Movements Induced by Shield Tunneling

Qianlong Tang,Limin Peng,Fudong Chen,Binbin Zhu,Mingfeng Lei,Gang Zhou

doi:10.1155/2021/8858874

Qianlong Tang, Limin Peng + Show 4 more

Open Access

https://doi.org/10.1155/2021/8858874

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Abstract

The process of shield tunnel excavation would inevitably cause surrounding ground movement, and excessive displacement in the soil could lead to large deformation and even collapse of the tunnel. The methods estimating convergence deformation around tunnel opening is summarized. Then, a universal pattern of displacement boundary condition around the tunnel cavity is originally introduced, which is solved as the combination of three fundamental deformation modes, namely, uniform convergence, vertical translation, and ovalization. The expression for the above-mentioned displacement boundary condition is derived, by imposing which the analytical solution for ground movements, based on the stress function method, is proposed. The reliability and applicability of this proposed solution are verified by comparing the observed data in terms of surface settlement, underground settlement, and horizontal displacement. Further parametric analyses indicate the following: (1) the maximum settlement increases linearly with the gap parameter and the tunnel radius, while it is negatively related to the tunnel depth; (2) the trough width parameter is independent of the gap parameter and the radius, while it is proportional to the tunnel depth. This study provides a new simple and reliable method for predicting ground movements induced by shield tunneling.

Highlights

IntroductionAn increasing urbanization has led to the over-crowded ground transportation issue around the world [1,2,3]
Over the last decade, an increasing urbanization has led to the over-crowded ground transportation issue around the world [1,2,3]
Further analysis indicates that when the gap parameter increases by 2 times, the trough width parameter only increases by 1.35%, and when the radius increases by 1 time, the trough width parameter only increases by 0.47%. erefore, it can be considered that the trough width parameter is independent of the gap parameter and the radius

Summary

Introduction

An increasing urbanization has led to the over-crowded ground transportation issue around the world [1,2,3]. Benefiting the aforementioned advantages, the analytical method has become the primary approach to compute tunneling-induced ground movements This method is conducted by developing mathematical equations satisfying soil behavior and solving them based on special boundary conditions. As for analytical prediction for tunneling-induced ground movement, limitations still exist for both the stress function method and displacement boundary condition, and further researches are still needed to be conducted. Looking at these challenges, this paper originally introduces a universal pattern of displacement boundary condition around the tunnel cavity (defined as the generalized displacement boundary ) based on the three fundamental deformation modes. E method associated with engineering properties is introduced to estimate the characteristic parameters of the generalized displacement boundary

The Generalized Displacement Boundary

Model Validation

Findings

Conclusion