Railway Alignment Optimization and Seismic Responses of High-Speed Railway Bridge Considering the Spatial Effects of Mountainous-Plateau

Abstract

Topographic effects significantly influence the propagation of seismic activity; however, research on the differences between mountainous and plateau terrains remains scarce. This paper focused on the 2008 Wenchuan earthquake, analyzing a five-span high-speed railway simply supported by a bridge through dynamic time-history analysis. Stations were categorized into mountainous and plateau groups based on their average shear wave velocity for the top 30[Formula: see text]m ([Formula: see text] values and elevation, aiming to explore the impact of terrain differences on seismic actions by comparing structural responses between the two groups. This study revealed an exponential relationship between structural responses and the rupture distance ([Formula: see text])/peak ground acceleration (PGA), with a rapid decrease in response when [Formula: see text]/PGA was below 100 and subsequent stabilization. Additionally, the sites were segmented into three zones according to the epicentral distance. The findings highlighted that the average PGA value of the mountain group was 2.7 times that of the plateau group in Region I, and the value decreased to 1.93 times that in Region II. However, the average PGA value of the plateau group slightly exceeded that of the mountain group in Region III. By comparing the PGA values of stations with similar fault distances within these regions, it was discovered that elevation could amplify seismic motion up to 4.59 times for smaller fault distances, with minimal amplification effects observed for larger fault distances. Finally, by examining damage to key components such as rails, beams, bearings, and piers and employing the kriging interpolation method to produce a regional seismic response cloud map, instances of high-speed railways constructed post-Wenchuan earthquake serve as evidence to corroborate the findings.