Dynamic Responseand Accumulative Deformation of Modified Expansive Soil of Heavy-haul Railway under Wetting Action

被引：0
|
作者：
Liu W. [1 ,2 ]
Xu Y. [1 ]
Cai Y. [3 ]
Huang X. [1 ]
机构：
[1] School of Civil Engineering, Central South University, Changsha
[2] National Engineering Research Center of High Speed Railway Construction Technology, Central South University, Changsha
[3] College of Water Resources and Civil Engineering, Hunan Agricultural University, Changsha
来源：
Tiedao Xuebao/Journal of the China Railway Society | 2023年 / 45卷 / 02期
关键词：
accumulative strain; dynamic response; heavy-haul railway; modified expansive soil; wetting effect;
D O I：
10.3969/j.issn.1001-8360.2023.02.014
中图分类号：
学科分类号：
摘要：
Based on the test section of the modified expansive soil subgrade of the Inner-Mongolia-Jiangxi Heavy-Haul Railway, the field vibration excitation tests under different axle loads and service environment conditions were carried out for cement modified soil embankment and lime modified soil cutting to analyze the distribution characteristics of dynamic stress, dynamic acceleration and the development law of vibration cumulative deformation. Then the dynamic wetting deformation tests of plain expansive soil, cement modified soil and lime modified soil under four different moisture contents and four different stress levels were carried out through indoor dynamic triaxial tests, to study the effects of wetting amplitude and dynamic stress amplitude on the cumulative strain characteristics of expansive soil and modified soil. The results show that the attenuation of dynamic stress and dynamic acceleration at the bottom of the subgrade bed can reach 80%. The attenuation speed of dynamic stress and acceleration along the subgrade depth increases with the increase of subgrade stiffness. At the same depth, the dynamic response in immersion is greater than that in natural state, and the influence is more significant with the increase of axle load. The wetting effect significantly weakens the subgrade attenuation ability to dynamic stress and dynamic acceleration. The immersion resistance of cement modified soil is stronger than that of lime modified soil. The cumulative deformation of the subgrade surface increases sharply with the increase of vibration times and axle load after immersion, and under the same vibration times, the cumulative strain of plain expansive soil and the modified soil increases sharply after the wetting amplitude exceeds 2% above the optimal moisture content. The increasing rate of cumulative deformation increases with the increase of dynamic stress. The accumulative deformation rate of the modified soil is only 1/8 ~ 1/5 of that of the plain expansive soil. The lime and cement can effectively inhibit the wetting deformation of the expansive soil. Finally, the cumulative strain prediction model based on the dynamic triaxial test results is established by data fitting, and the empirical relationship between the model parameters and the wetting amplitude of the plain expansive soil and the modified soil is presented. © 2023 Science Press. All rights reserved.
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页码：127 / 138
页数：11
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