doi: 10.16186/j.cnki.1673-9787.2023020075

Received: 2023/02/27

Revised: 2023/04/18

Published: 2024/03/25

Discrete element numerical simulation analysis of dynamic response of high-speed railway subgrade in goaf sites

REN Lianwei1，2， WANG Ziqiang1， ZOU Youfeng3， DUN Zhilin1，2， YANG Wenfu4

1. School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China; 2. Henan Engineering Research Center for Ecological Restoration and Construction Technology of Goaf Sites; 3. School of Surveying and Land Information Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China; 4. Coal Geological Geophysical Exploration Surveying & Mapping Institute of Shanxi Province, Jinzhong 030600, Shanxi, China

Abstract:  Objectives High-speed railways running through goaf sites pose significant safety risks. This study aims to investigate the dynamic response patterns of high-speed railway subgrades in goaf sites. Methods Seventeen numerical models of high-speed railway subgrades in goaf sites were established using the 3DEC discrete element software. Settlement deformation and dynamic stress distribution within the subgrade under varying train loads were analyzed. The dynamic response differences between ballasted and ballastless track subgrades were compared. Additionally, the effects of goaf width and thickness on the dynamic response distribution were examined. Results Compared with the ballastless track, the dynamic stress amplitude within the ballasted track subgrade is significantly higher, but the attenuation rate of dynamic stress is also greater. The time-history curves of dynamic stress and dynamic displacement exhibit a gradual increase in phase differences along the depth direction of the subgrade. As the loading time increases, the amplitude of dynamic displacement gradually increases, although the rate of increase slows down over time, while the dynamic stress amplitude remains essentially unchanged. A linear relationship exists between the dynamic stress and displacement amplitudes and the train’s axle load, with both increasing proportionally as the axle load increases. The width and thickness of the goaf significantly affect the amplitude of dynamic displacement caused by train loads. As the goaf width and thickness increase, the dynamic displacement amplitude also increases. However, when the mining width exceeds a certain threshold, the dynamic displacement amplitude begins to decrease. Conclusions Differences in train load, subgrade track type, and goaf site characteristics significantly influence the distribution of dynamic responses within the subgrade. These findings provide valuable theoretical references for ensuring the safe operation of high-speed railways in goaf sites.

Key words: goaf site； high-speed railway subgrade； dynamic stress； dynamic displacement； discrete element