The Testing And Analysis On The Dynamic Response Of Cross-river Road Tunnel Considering Interaction Between Soils And Structures

Vehicle movement in shield tunnel can impose dynamic effect on the tunnel and the response of the tunnel to such effect is influenced by the property of the soil layers around. In the article, Nanjing Yangtze River Tunnel which runs across soft soil layer and sandy soil layer is taken as an example to test the vibration performance of the linings and the road slabs inside the tunnel under the stimulation of vehicle loads through the three methods, namely field measurement, modal finite element analysis and dynamic finite element analysis; to simulate the influence of soil-structure interaction on tunnel modality; to analyze the displacement, the acceleration and the excess pore water pressure of the soil body around the tunnel and the changes thereof under load effect, and the influence of the soil property on the tunnel, as well as the dynamic response of the soils around. The obtained research achievements are as follows:(1) The natural vibration frequency of Nanjing Yangtze River Tunnel in soft soil layer and sandy soil layer are 0.287Hz and 0.544Hz; meanwhile, it is found that soil-structure interaction can significantly reduce the natural vibration frequency of the tunnel, thus to suppress the stimulation of the high-order vibration of the tunnel.(2) By means of vibration measurement, the maximum acceleration of the tunnel segments during traffic time is 9.4mm/s2 and the dominant frequency of the tunnel in soft soil layer are 0.19Hz and 2.56Hz, lower than 0.31Hz and 3.56Hz, which are in sandy soil layer; meanwhile, it is found that the dynamic response amplitude of the tunnel segments in soft soil is greater than that in sandy soil under the same load effect.(3) The displacement, the acceleration and the excess pore water pressure of the soil body around the tunnel and the changes thereof under vehicle load effect have been simulated; meanwhile, it is found that the dynamic response amplitude of the soft soil layer is smaller than that of the sandy soil layer under the same load effect.