Transverse Seismic Vulnerability Analysis Of Shield Tunnel Based On Pseudo-static Method

The damage probability of shield tunnels under different earthquake intensities can be obtained intuitively by performance-based vulnerability analysis method.The main difficulty lies in the fact that the structural vulnerability analysis based on numerical simulation requires a large amount of computational analysis,and the dynamic time-history method cannot meet the requirements for computational efficiency;The performance level of shield tunnels is currently lacking wel-defined classification criteria,and the selection of quantitative indicators is relatively simple.Based on summarizing the research status at home and abroad,this dissertation investigates the vulnerability of shield tunnels under transverse seismic earthquake.The main research contents include:(1)The pseudo-static analysis method of underground frame structure is introduced.The cross-section finite element model of the shield tunnel considering the soil-structure interaction and joint effect is established.Finally,the complete PUSHOVER analysis process of shield tunnel transverse earthquake is established.And its validity and applicability are verified by comparing with the results of dynamic time-history analysis.(2)Taking a metro tunnel section in southwest China as an example,the PUSHOVER method is used to analyze the seismic failure mode of the transverse section of the shield tunnel,and the deformation and stress of the whole structure process are obtained.By defining characteristic events and monitoring the indicators affecting the use of shield tunnels,the reasonable parameters defining the performance level of shield tunnels are obtained.(3)The current performance level of shield tunnels is defined directly through the occurrence of characteristic events,regardless of the selection of quantitative indicators for structural performance levels,thus avoiding the interference of uncertainty of quantitative indicators on the vulnerability of shield tunnels.The transverse seismic vulnerability of shield tunnels is calculated by Monte Carlo method.(4)The parameter analysis of the calculation parameters of the shield tunnel finite element model is carried out.At the same time,the influence of the correlation of soil parameters and the correlation of structural parameters on the vulnerability results is analyzed.