Deformation behaviors and mechanical mechanisms of largespan tunnels in sedimentary rock: insights from field monitoring and numerical modeling

Yun Cheng , Zhanping Song , Guannan Zhou , Zhaoyu Wang , Zhiwei Xu , Wenjun Qian , Tengtian Yang , Yinhao Sun

Abstract

Under train-induced disturbances, sedimentary rocks at the tunnel floor heave causes inverted arch cracking and track deformation. However, no consensus has yet been reached regarding the causes of floor heave. This paper presented a case study of GZ tunnel, in which the uplift deformation of the inverted arch was investigated through on-site inspection, deformation monitoring, and 3D numerical simulation. The deformation characteristics and underlying mechanisms were analyzed, and the original invert was subsequently reconstructed using a renovation scheme involving steel cushion beam hanging rails and transitional speed restrictions. The evolution of contact stress between the inverted arch and bedrock, as well as the deformation of the tunnel vault and inverted arch settlement, were systematically examined. The proposed remediation involved deepening the original invert structure by 1.56 m, which proved effective in mitigating and suppressing uplift deformation. The performance and applicability of the reconstructed invert were evaluated by analyzing the contact stress evolution, vault deformation, and settlement behavior based on field monitoring data and numerical modeling. The contact stress exhibited a gradual increase followed by convergence, with final values of 155.09 kPa, 167.57 kPa, and 221.69 kPa at the monitored sections. No abrupt stress changes were observed over 30 to 55 days, indicating a stable stress state. The average uplift displacement of the inverted arch surface was reduced by 73.17% compared with pre-reconstruction conditions, indicating that the reconstructed invert exhibited stable structural adaptability and effectively controlled both vault settlement and arch uplift.

Key Words

deformation behavior; inverted arch structure; mechanical mechanisms; sedimentary rock tunnel; site - monitoring

Address

Yun Cheng — School of Civil Engineering, Yancheng Institute of Technology, 1 Xiwang-ro, Tinghu-gu, Yancheng, 224051, Republic of China Jiangsu Coastal Transportation Infrastructure Intelligent and Disaster Prevention Engineering Research Center, 1 Xiwang-ro, Tinghu-gu, Yancheng, 224051, Republic of China College of Civil Engineering, Xi'an University of Architecture and Technology, 13, Yanta-ro, Beilin-gu, Xi'an, 710055, Republic of China Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, 13, Yanta-ro, Beilin-gu, Xi'an, 710055, Republic of China
Zhanping Song — College of Civil Engineering, Xi'an University of Architecture and Technology, 13, Yanta-ro, Beilin-gu, Xi'an, 710055, Republic of China Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, 13, Yanta-ro, Beilin-gu, Xi'an, 710055, Republic of China
Guannan Zhou, Tengtian Yang, Yinhao Sun — Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, 13, Yanta-ro, Beilin-gu, Xi'an, 710055, Republic of China; China Railway Construction Bridge Engineering Bureau Group Co., Ltd., 32, Central west-ro, Airport economic zone-gu, Tianjin, 300300, Republic of China
Zhaoyu Wang, Zhiwei Xu, Wenjun Qian — School of Civil Engineering, Yancheng Institute of Technology, 1 Xiwang-ro, Tinghu-gu, Yancheng, 224051, Republic of China Jiangsu Coastal Transportation Infrastructure Intelligent and Disaster Prevention Engineering Research Center, 1 Xiwang-ro, Tinghu-gu, Yancheng, 224051, Republic of China

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