| 疲劳动剪应变门槛与武广高铁无碴轨道路堑基床长期动力稳定 |
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| 引用本文： | 刘晓红,杨果林,方 薇.疲劳动剪应变门槛与武广高铁无碴轨道路堑基床长期动力稳定[J].岩土力学,2010,31(Z2):119-124. |
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| 作者姓名： | 刘晓红 杨果林 方 薇 |
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| 作者单位： | 1.中南大学 土木建筑学院，长沙 410075；2.湖南理工学院 土木建筑系，湖南 岳阳 414000 |
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| 基金项目： | 国家自然科学基金资助项目(No. 50778180)；铁道部科技研究开发计划项目(No. 2005K002-B-2-1)。 |
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| 摘 要： | 针对武广高铁无碴轨道红黏土路堑基床长期动力稳定性问题,利用改造后的应力控制式动三轴仪代替国内尚无的剪应变控制式共振柱仪,测试土体疲劳动剪应变门槛值,提出了一套完整的试验方案和数据处理方法,为疲劳动剪应变门槛的确定开辟了新的试验途径。通过疲劳动三轴试验,获得了9种试验条件下红黏土疲劳动剪应变门槛值。按曲线走势特征,红黏土Ed-lgN曲线可分为稳定型、临界型、破坏型3类,且不同试验条件下同类型的曲线具有相似的走势特征;探讨了含水比、围压对红黏土疲劳动剪应变门槛的影响,给出了简单实用的疲劳动剪应变门槛经验估算公式;基于室内试验及现场动响应测试成果,采用动剪应变法初步评价了武广高铁无碴轨道红黏土路堑基床的动力稳定性,给出了不同物理状态下红黏土基床最小换填厚度建议值。研究成果为我国高速铁路无碴轨道土质路基动力稳定性评价及路堑基床换填厚度的确定提出了新的思路,也为红黏土疲劳特性的深入研究提供了宝贵的第一手资料。
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| 关 键 词： | 疲劳动剪应变门槛 长期动力稳定 换填厚度 路堑基床 红黏土 |
| 收稿时间： | 2010-06-24 |
Fatigue dynamic shear strain threshold and long-term dynamic stability of cutting bed under ballastless track of Wuhan-Guangzhou high-speed railway |
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| LIU Xiao-hong,YANG Guo-lin,FANG Wei.Fatigue dynamic shear strain threshold and long-term dynamic stability of cutting bed under ballastless track of Wuhan-Guangzhou high-speed railway[J].Rock and Soil Mechanics,2010,31(Z2):119-124. |
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| Authors: | LIU Xiao-hong YANG Guo-lin FANG Wei |
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| Institution: | 1. School of Civil and Architectural Engineering, Central South University, Changsha 410075, China; 2. Department of Civil Engineering and Architecture, Hunan Institute of Science and Technology, Yueyang, Hunan 414000, China |
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| Abstract: | In view of the long-term dynamic stability of red clay cutting bed under ballastless track of Wuhan-Guangzhou high-speed railway, the reformed stress controlled dynamic triaxial test apparatus is utilized to measure fatigue dynamic shear strain threshold firstly, replacing the shear strain controlled resonant column test apparatus not existing at home now. A complete set of test program and data processing method are put forward, which open up a new test way of measuring fatigue dynamic shear strain threshold. The values of fatigue dynamic shear strain threshold of red clay are obtained through fatigue dynamic triaxial tests under 9 kinds test conditions. According to curves trend features, - curves of red clay (where is dynamic modulus, N is number of vibration) can be classified as three types: the stable type, critical type and destructive type; and the same type curves have similar trend characteristics under different test conditions. Influences of water content ratio and confining pressure on fatigue dynamic shear strain threshold of red clay are discussed; and a simple and practical empirical formula for estimating fatigue dynamic shear strain threshold is also given. Based on results of laboratory test and field dynamic response test, the long-term dynamic stability of red clay cutting bed under ballastless track of Wuhan-Guangzhou high-speed railway is preliminary evaluated; and the corresponding minimal replacement thicknesses of red clay under different physical conditions are also given. A new train of thought is put forward for evaluating long-term dynamic stability and ensuring replacement thickness of cutting bed under ballastless track of high-speed railway in China. Valuable first hand data for the further study of fatigue characteristics of red clay are provided. |
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| Keywords: | fatigue dynamic shear strain threshold long-term dynamic stability replacement thickness cutting bed red clay |
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