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| Study on long-term settlement of shield tunnels parallelly undercutting existing highway tunnels with variable spacing under cyclic dynamic loading |
| He Jiacheng1,2, Zhu Chi3, Fu Jinyang3*, Sun Qianhui3, Li Yanan4
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1. China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063, Hubei, China;
2. National and Local Joint Engineering Research Center for Underwater Tunnel Technology, Wuhan 430063, Hubei, China;
3. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China;
4. Yellow River Engineering Consulting Co., Ltd., Zhengzhou 450003, Henan, China |
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Abstract To reveal the long-term settlement behaviour of an existing highway tunnel caused by a newly constructed shield tunnel passing beneath it in parallel under cyclic train loading, the Yellow River Crossing Tunnel of Jinan Rail Transit Line M2 was taken as the engineering background. Soil dynamic deformation parameters were obtained through laboratory dynamic triaxial tests, and a cumulative plastic deformation-based settlement model was established. Dynamic finite element simulations were then conducted to analyse the ground dynamic stress distribution and the long-term settlement response of the existing highway tunnel under different tunnel clear spacings. The results showed that the ground dynamic stress was mainly concentrated within 10 m beneath the newly constructed shield tunnel, accounting for approximately 60%~70% of the total dynamic stress variation. The settlement of the existing highway tunnel increased with tunnel spacing, while the contribution of vehicle dynamic loading first increased and then decreased. Based on multiple working conditions, a quantitative relationship between tunnel clear spacing and long-term settlement was fitted. The proposed model and fitted formula reflected the controlling effect of tunnel spacing on long-term settlement and provided a targeted method for settlement prediction and safety assessment in similar shield tunnelling undercrossing projects.
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Published: 12 October 2026
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