重载铁路水泥改良膨胀土路基动力特性数值研究  

Numerical Research on the Dynamic Features of Cement-Stabilized Expansive Soil Subgrade of Heavy Haul Railway

作　　者：商拥辉[1,2] 尹方芳 徐林荣[2,4] 陈钊锋 SHANG Yonghui;YIN Fangfang;XU Linrong;CHEN Zhaofeng(Institute of Architecture and Engineering,Huanghuai University,Zhumadian 463000,China;School of Civil Engineering,Central South University,Changsha 410075,China;Logistic department,Huanghuai University,Zhumadian 463000,China;High Speed Railway Construction Technology National Engineering Laboratory,Changsha 410075,China)

机构地区：[1]黄淮学院建筑工程学院,河南驻马店463000 [2]中南大学土木工程学院,长沙410075 [3]黄淮学院后勤处,河南驻马店463000 [4]高速铁路建造技术国家工程实验室,长沙410075

出　　处：《铁道标准设计》2020年第10期18-23,共6页Railway Standard Design

基　　金：国家自然科学基金项目(51778634,51078358);河南省科技厅攻关项目(201202310264);河南省教育厅重点项目(20B580003)。

摘　　要：相比普铁与高铁而言,列车动载作用下重载铁路路基的动力特性更突出。依托浩吉重载铁路工程背景建立"列车-有砟轨道-基床-地基"三维数值模型,对不同荷载条件下重载铁路水泥改良膨胀土路基的动力特性进行分析。同时,结合室内动三轴试验,获取水泥改良膨胀土填料临界动应力,并建立填料累积变形经验模型,综合"强度-变形"指标对重载铁路水泥改良膨胀土路基的长期动力稳定性进行评估。结果表明:路基动应力受轴重影响敏感性大于车速,轴重25~30 t重载列车动载作用路基面动应力是预留客运列车作用时的1.2倍;不同列车荷载作用下重载铁路改良膨胀土路基的动应力沿深度逐渐衰减,动力影响深度是基床设计厚度(2.5 m)的1.2~1.6倍,但影响范围内路基动应力水平远小于填料临界动应力范围,说明路基动强度稳定满足要求;结合动三轴试验"应变-振次"稳定性曲线,建立考虑振次、应力水平等多因素的水泥改良膨胀土填料累积变形经验模型,预测400万振次基床表面累积变形为5.5~6.5 mm,其中前150万振次累积变形量占比达85%以上,说明路基动变形稳定满足要求;数值结果与文献测试数据吻合,验证模型的合理性。Compared with ordinary and high-speed railways,the dynamic features of the subgrade are more prominent under the dynamic load of a heavy-haul train.Based on the engineering background of the Haolebaoji-Ji’an Heavy-haul Railway,a three-dimensional numerical model is established to analyze the dynamic features of the cement-stabilized expansive soil subgrade of the heavy-haul railway under different load conditions.At the same time,combined with the indoor dynamic triaxial test,the critical dynamic stress of the cement-modified expansive soil filling is obtained,and the empirical model of the cumulative deformation of the filling is established,and the long-term dynamic stability of the cement-modified expansive soil subgrade of the heavy haul railway is evaluated by combining the"strength-deformation"index.The results show that the subgrade dynamic stress affected by axle load is greater than that of vehicle speed,and the dynamic stress of the subgrade surface under the dynamic load of 25~30 t heavy-duty train is 1.2 times more than that under the dynamic load of the reserved passenger train;the dynamic stress of improved expansive soil subgrade of heavy-duty railway decreases gradually along the depth under different train loads,and the dynamic impact depth is 1.2~1.6 times more than the designed thickness of subgrade bed(2.5 m),but the dynamic stress level of subgrade within the scope of influence is far smaller than the critical dynamic stress range of the filling,which indicates that the dynamic strength stability of the subgrade meets the requirements;combined with the dynamic triaxial test"strain vibration number"stability curve,an empirical model of cumulative deformation of cement improved expansive soil filling covering multiple factors such as vibration number and stress level is established,which predicts that the cumulative deformation of the bed surface with 4 million vibration times is 5.5~6.5 mm,and the cumulative deformation of the first 1.5 million vibration times accounts for more than 85%,whic

关 键 词：路基 水泥改良膨胀土 动力特性 数值模拟 重载铁路 

分 类 号：U213.1[交通运输工程—道路与铁道工程]