Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

Lin Wu,Wei Wang,Hong Guo,Xiancong Meng,Xiedong Zhang

doi:10.3390/app11167577

Lin Wu, Wei Wang + Show 3 more

Open Access

https://doi.org/10.3390/app11167577

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Abstract

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

Highlights

With the increasing shortage of underground space in cities, large diameter twin tunnels with near distances are becoming more common
There are many tunnels with a diameter of d1 = 5–10 m under train vibration [1,2,3]
Yang et al conducted a systematic study on the dynamic characteristics of single tunnel structure and its surroundings under train operation vibration [16,17]

Summary

Introduction

With the increasing shortage of underground space in cities, large diameter twin tunnels with near distances (i.e., smaller than 0.25 times diameter) are becoming more common. The dynamic characteristics of d3 ≥ 15 m cross-river twin tunnels under train vibration are different from those of small diameter twin tunnels. Yang et al conducted a systematic study on the dynamic characteristics of single tunnel structure and its surroundings under train operation vibration [16,17]. It is necessary to re-construct and anchor the damaged tunnel to ensure the tunnel’s safety He et al [23] established a 2.5-dimensional model that can predict train-induced vibration in tunnels with any cross-section. From the research on train vibration in single and twin tunnels, closely spaced twin tunnels (smaller than 0.25 times diameter) have become more common. The above analysis can be used to quantitatively compare the dynamic characteristics of super-large (D = 15.2 m) and small (d = 6.2 m) diameter twin tunnels under train vibrations

Project Background and Type A Train

Micro-Parameters of Silty Sand and C60 Concrete

Twin Tunnels Model in DEM

Findings

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