Study on dynamic response and permanent deformation of the pier and its surrounding sites induced by high-speed train loads in seasonally frozen regions

Abstract

Vibration induced by high-speed trains (HSTs) is well-known problem, which can deteriorate the embankments, piers and other structures along the railways. Particularly, the problem is more serious due to the freeze-thaw cycle of soil in seasonally frozen regions. In the present study, a series of field experiments are conducted to measure the HST-induced vibration of the pier and its surrounding different sites on the Harbin-Dalian high-speed railway (HSR) in seasonally frozen regions. The characteristics of the vibration in the time and frequency domains are analyzed based on the field measurement results. And the site effects are investigated by the frequency response function (FRF). In addition, the finite element model is established to study the vibration propagation characteristics along the soil surface and interior in different season by the analyzing the variation laws of acceleration peak (Amax) and deviatoric stress (qd), and predict the permanent deformation (Dp) of surface. The results show that the vibration characteristics of the pier and foundation sites are completely different. The Amax decreases in the form of a power function with the distance (R) from the pier in the unfrozen and frozen conditions. Moreover, the distributions of the qd of soil surface in freezing season are obviously different from those in non-freezing season, but the difference between them decreases gradually with the increase of depth (D). The growth speed of Dp decreases with the increase of the time, and the Dp value will eventually trend to a stable value.