Deformations of Subway Tunnels Induced by the Overcrossing Jacked Box Tunnels

Wei Liu,Lingyi Miao,Huajing Zhao,Xiangyang Xu,Yinlong Wu

doi:10.3390/sym13101800

Abstract

The rectangular utility tunnels have been increasingly built in urban areas in recent decades. In this paper, a case of jacked box tunnels built closely over-crossing the existing subway tunnels in Suzhou, China, is presented. The tunneling-induced deformation of the subway tunnels is measured and analyzed. The measurement indicates that the subway tunnels are uplifted and subjected to the overcrossing box tunneling. As compared, the longitudinal deformation of the range that locates under the box tunnels is more significant than that outside the range. The tunneling-induced deformation of the left subway tunnel is relatively higher than that of the right one. The numerical simulation is performed for validation. The numerical result is agreed with the in-situ measurements. Moreover, the simulation reveals that the presence of friction in jacked tunnels causes the extra uplift deformation of subway tunnels. The higher the friction, the is the deformation. It is affirmed that using the effective lubrication not only facilitates the tunnel jacking but also inabilities the tunneling-induced deformation of underlying tunnels

Highlights

Overcrossing Jacked Box Tunnels.In recent years, there has been a rapid development of underground construction in China
This paper aims to study the influence of the jacked box tunneling on the deformation of the existing subway tunnels
The deformations of subway tunnels induced by overcrossing jacked box tunneling are investigated

Summary

Introduction

There has been a rapid development of underground construction in China. Rectangular tunnels with high space utilization have been gradually used for building urban utility tunnels. As one of the typical trenchless techniques, jacking box tunneling is widely adapted for underground construction. The excavation in box tunneling triggers the significant release of soil stress, i.e., more than that in circular tunnels [1,2]. The inappropriate support on the working face causes unexpected great ground movement and, even worse, a collapse or blowout failure [3,4,5,6,7,8,9]. The interaction between the jacked linings and the surrounding soils impacts the soil movement. The disturbance on the existing underground structures when the jacked box tunnel passing by is complicated

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Conclusion