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Analysis of the Dynamic Effect of Traffic Load on Shallow Multi-tube Tunnel Structure
(1. School of Civil Engineering, Fujian University of Technology, Fuzhou 350118; 2. Key Laboratory of Fujian Universities for Underground Engineering, Fuzhou 350118; 3. Fujian Provincial Key Laboratory of Advanced Technology and Informatization in Civil Engineering, Fuzhou 350118; 4. China Railway 24th Bureau Group Fujian Railway Construction Co. Ltd., Fuzhou 351111)
Abstract Taking as a study case a shallow four-tube tunnel project passing under a highway in Fujian, this paper establishes a road surface-surrounding rock-tunnel vibration analysis model based on vehicle load dynamics theory to analyze the dynamic response of the shallow multi-tube tunnel structure under vehicle load action. The results show that the time history curve of vertical displacement presents an "inverted bimodal" shape with semi-intense oscillation, while the peak displacement generated by the vehicle load action of one carriageway is much larger than that of the other carriageway in the opposite direction, and the dynamic displacement effect on multi-tube tunnel is small. The dynamic stress is distributed in an asymmetric "clover" shape along the circumference of the tubes and concentrated in the shoulder area. The dynamic stress amplitude of the shoulder increases significantly when the dual carriageway is fully loaded compared with the other solutions, and such a long-term effect should not be neglected. This paper thus puts forward a reasonable mode for the load distribution of highway lanes. The elasticity modulus of each rock-soil mass has a large impact on the transmission of dynamic stress, and the larger the surface elastic modulus is, the faster the attenuation of the dynamic stress will be. However, when it reaches the tunnel structure, it will start reflecting and rising. Therefore, increasing the stiffness of the road surface or the range of the tunnel reinforcement ring can reduce the impact of dynamic stress on the tunnel. The reasonable control of traffic density can significantly reduce the dynamic stress of the tunnel shoulder, while cyclic vehicle load actions will increase the peak of the tunnel dynamic stress by 60.98%~81.3%. By analyzing the degree of impact, it is found that the dynamic stress in the tunnel surrounding rock when the four lanes are in a full traffic jam is 12.68 times higher than that when there is only a half-carriageway traffic jam.
Abstract：
Taking as a study case a shallow four-tube tunnel project passing under a highway in Fujian, this paper establishes a road surface-surrounding rock-tunnel vibration analysis model based on vehicle load dynamics theory to analyze the dynamic response of the shallow multi-tube tunnel structure under vehicle load action. The results show that the time history curve of vertical displacement presents an "inverted bimodal" shape with semi-intense oscillation, while the peak displacement generated by the vehicle load action of one carriageway is much larger than that of the other carriageway in the opposite direction, and the dynamic displacement effect on multi-tube tunnel is small. The dynamic stress is distributed in an asymmetric "clover" shape along the circumference of the tubes and concentrated in the shoulder area. The dynamic stress amplitude of the shoulder increases significantly when the dual carriageway is fully loaded compared with the other solutions, and such a long-term effect should not be neglected. This paper thus puts forward a reasonable mode for the load distribution of highway lanes. The elasticity modulus of each rock-soil mass has a large impact on the transmission of dynamic stress, and the larger the surface elastic modulus is, the faster the attenuation of the dynamic stress will be. However, when it reaches the tunnel structure, it will start reflecting and rising. Therefore, increasing the stiffness of the road surface or the range of the tunnel reinforcement ring can reduce the impact of dynamic stress on the tunnel. The reasonable control of traffic density can significantly reduce the dynamic stress of the tunnel shoulder, while cyclic vehicle load actions will increase the peak of the tunnel dynamic stress by 60.98%~81.3%. By analyzing the degree of impact, it is found that the dynamic stress in the tunnel surrounding rock when the four lanes are in a full traffic jam is 12.68 times higher than that when there is only a half-carriageway traffic jam.
YAO Zhixiong1,
2,
3 JI Lei1 LIU Yaoxing1 HUANG Min4 ZHANG Zhongxing4 CUI Ying1
.Analysis of the Dynamic Effect of Traffic Load on Shallow Multi-tube Tunnel Structure[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(3): 107-117
2022, Vol. 59 