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Research on Mechanical and Deformation Characteristics of Large Diameter Shield Tunnels under Cyclic Loadings
(1. Jinan City Construction Group Co., Ltd., Jinan 250131; 2. School of Civil Engineering and Architecture, University of Jinan, Jinan250022; 3. The Engineering Technology Research Center for Urban Underground Engineering Supporting and Risk Monitoring of Shandong Province, Jinan 250022; 4. China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430063)
Abstract The cyclic vehicle loads on the shield tunnel during operation period always induce stress concentration and plastic strain accumulation, which lead to fatigue damage and cracking deformation of tunnel structures. Based on ABAQUS software and concrete plastic damage constitutive model (CDP), a numerical calculation model of double-deck shield tunnel was established, the internal force and deformation characteristics of tunnel structure and connecting bolts under different cyclic times were analyzed. The results show that (1) the internal force of tunnel segment and internal structure present periodic variation according to the cyclic vehicle loads. With the increase of loading frequency, the plastic strain zone of tunnel segment and internal structure increases, and the vertical displacement of internal structure increases. (2) The axial stress of connecting bolts also shows periodic variation, and the maximum axial stress appears in the middle of the connecting bolt. Under the cyclic load, the axial stress of the connecting bolt near the loading position is larger than that of the surrounding bolts. (3) Under the action of soil pressure and cyclic vehicle loads, stress concentration occurs at the bottom and waist of tunnel segments, where the plastic deformation accumulation is easy to occur at the stress concentration area.
Abstract：
The cyclic vehicle loads on the shield tunnel during operation period always induce stress concentration and plastic strain accumulation, which lead to fatigue damage and cracking deformation of tunnel structures. Based on ABAQUS software and concrete plastic damage constitutive model (CDP), a numerical calculation model of double-deck shield tunnel was established, the internal force and deformation characteristics of tunnel structure and connecting bolts under different cyclic times were analyzed. The results show that (1) the internal force of tunnel segment and internal structure present periodic variation according to the cyclic vehicle loads. With the increase of loading frequency, the plastic strain zone of tunnel segment and internal structure increases, and the vertical displacement of internal structure increases. (2) The axial stress of connecting bolts also shows periodic variation, and the maximum axial stress appears in the middle of the connecting bolt. Under the cyclic load, the axial stress of the connecting bolt near the loading position is larger than that of the surrounding bolts. (3) Under the action of soil pressure and cyclic vehicle loads, stress concentration occurs at the bottom and waist of tunnel segments, where the plastic deformation accumulation is easy to occur at the stress concentration area.
LI Chunlin1 ZHANG Xiwen2,
3 LIU Guangsen2,
3 LIU Junyan2 etc
.Research on Mechanical and Deformation Characteristics of Large Diameter Shield Tunnels under Cyclic Loadings[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(5): 47-53
2022, Vol. 59 