Improved hilbert spectral representation method and its application to seismic analysis of shield tunnel subjected to spatially correlated ground motions. Issue 111 (August 2018)

• Record Type: Journal Article
• Authors: Miao, Yu; Yao, Erlei; Ruan, Bin; Zhuang, Haiyang; Chen, Guoxing; Long, Xiaohong
• Is Part Of: Soil dynamics and earthquake engineering. Issue 111(2018)
• Page Start: 119
• Page End: 130
• Publication Date: 2018-08
• Subjects: Shield tunnel -- Intersegment opening width -- Multiple support excitation -- Identical support excitation -- Spatially correlated ground motions; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2018.04.050
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: A novel and efficient method for simulation of spatially correlated earthquake ground motions (SCEGMs), named as improved Hilbert spectral representation method, was presented. By using Hilbert–Huang transform (HHT), the known record can be decomposed into a series of intrinsic mode functions (IMFs) and a residual function. Targeting on each IMF, simulated IMFs for every field point were derived through a spatial correlation model. The frequency dependence of the spatial correlation structure was simplified such that only the correlation at the predominant frequency of each target IMF was considered. SCEGMs can then be obtained by superposition of simulated IMFs and the original residual function. Taking the Suai shield tunnel project in China as reference, the intersegment opening width response of shield tunnel under multiple support excitation (MSE) and identical support excitation (ISE) were investigated and compared. First, numerous accelerograms, including horizontal and vertical components, were generated based on selected real records and artificial acceleration time histories on bedrock to realize MSE. The generalized response displacement method (GRDM) in combination with a large-scale FEM model was then utilized to proceed with the study. Results showed that the MSE can lead to a higher opening width of tunnel in general. The distribution of longitudinal opening width under MSE is also different from that under ISE. The sharp variation of soil layer stiffness along the longitudinal direction of tunnel may lead to extremely large intersegment opening width or severe damage. Highlights: A novel and efficient method for simulation of spatially correlated earthquake ground motions was presented. The frequency dependence of the spatial correlation structure was extremely simplified. The generalized response displacement method and a large-scale FEM model was utilized to proceed with the study. The intersegment opening width response of shield tunnel under multiple- and identical-support excitation were compared.