Research on the Influence of Train Formation on the vibration Stress of Railway Subgrade in Seasonally Frozen Region

Abstract

In order to research the characteristics of subgrade vibration response under train vibration load, the finite element method is used to establish a three-dimensional numerical model of railway subgrade vibration response. Through numerical calculation, the vibration response of roadbed in different freezing periods and train formation is analyzed, and the influence of train formation in different seasons on dynamic stress, acceleration amplitude-frequency characteristics and amplitude attenuation law of roadbed is deeply studied. The results show that :(1) affected by the superposition of vibration, the dynamic stress amplitude and acceleration amplitude of the train both increase significantly with the increase of train number in each frequency band; (2) the amplitude of acceleration at the surface of the foundation bed is affected by the frozen state of the subgrade, and the amplitude of acceleration at different freezing periods at the bottom of the foundation bed is basically the same. The dynamic stress effective value in the freezing period is greater than that in the normal period, and the dynamic stress effective value in the spring thawing period is the smallest. The results provide theoretical basis for the permanent deformation of railway subgrade caused by train load in seasonal frozen soil area.