Dynamic Response Of Subgrade And Vibration Detection Of Defective Subgrade In Existed Railway Lines

After many years of operation,most of the existing railway lines have different degrees of disease,and the main disease is subgrade subsidence.At the same time,for the existing lines in the seasonally frozen regions,there are different degrees of mud-slurry,uneven frost heave deformation,etc.during the spring period.The forced vibration caused by train passes is the main factor that causes the disease of the subgrade.This paper takes the existing line-based regulation project as the engineering background,studies the dynamic response of the subgrade of the existing railway,and the vibration detection method of the disease roadbed.The main achievements are:1.In order to study the vibration characteristics of railway subgrade at different periods in seasonal frozen soil area,the on-site monitoring of the subgrade vibration acceleration caused by the passing of trains during the frozen period and normal period of the Baozhong railway line in a typical seasonal frozen area,the law of vibration acceleration response in three directions of roadbed and side slope of embankment in different periods is obtained.2.Combined with the roadbed regulation works of the engineering site,the typical embankment sections are selected to study the dynamic response of the heavy haul and low-speed Railway Subgrade along the deep roadbed.The corresponding vibration acceleration response time history curve and the attenuation law of roadbed vibration response along the roadbed depth are obtained.3.Through monitoring and analyzing the vibration response of railway subgrade before and after reinforcement and reinforced section and unreinforced section,a method for detecting the vibration response of the disease subgrade is proposed,vibration acceleration,vibration speed,and dynamic displacement were determined as indicators for the detection of subgrade vibration.4.Combined with the disease control project of the Da Zhun railway,the vibration detection of the existing roadbed is carried out.The vibration acceleration,vibration velocity and dynamic displacement response of different roadbeds are obtained.Summarizes a specific method for detecting the vibration response of diseased roadbed and whether the roadbed is a method to determine the roadbed of disease.