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工程科学与技术:2020,52(5):170-177
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橡胶颗粒-砂混合物新型路基填料动力参数特性的试验研究
(1.中南大学 土木工程学院,湖南 长沙 410083;2.中南大学 教育部重载铁路工程结构重点实验室,湖南 长沙 410083)
Experimental Study on Dynamic Parameter Characteristics of New Subgrade Filler Composed of Granular Rubber-Sand Mixtures
(1.School of Civil Eng., Central South Univ., Changsha 410083, China;2.MOE Key Lab. of Eng. Structures of Heavy Haul Railway, Central South Univ., Changsha 410083, China)
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投稿时间:2020-01-06    修订日期:2020-03-14
中文摘要: 为研究橡胶颗粒与砂土混合物这种新型路基填料在循环列车荷载作用下的动力参数特性,进行室内固结不排水动三轴试验,分析了橡胶颗粒含量、围压以及加载频率等因素对橡胶颗粒-砂混合物动剪切模量、阻尼比等特性的影响,研究结果表明:应变一定时,混合物的动剪切模量随着橡胶颗粒含量的增加而减小,随着围压的增大而增大,随着加载频率的增加而轻微减小;基于Hardin-Drnevich双曲线模型对动剪切模量试验结果进行拟合,得出最大动剪切模量,发现最大动剪切模量随着橡胶颗粒含量的增加而减小;混合物的阻尼比随着橡胶颗粒含量的增大而增大,随着围压的增大而减小,加载频率对阻尼比的影响较小;基于试验结果,建立了橡胶颗粒-砂混合物阻尼比与动剪应变的关系式。最后,基于柔性橡胶颗粒与刚性砂土颗粒的微观接触特性,分析了橡胶颗粒对混合物动剪切模量以及阻尼比的影响机理。综合研究结果得出:橡胶颗粒含量不宜超过20%,此时橡胶颗粒-砂混合物作为新型路基填料的动剪切模量可以满足要求,阻尼比较大,具有良好的减震耗能效果。
Abstract:To study the dynamic parameter characteristics of the granular rubber-sand mixtures (a new type of subgrade filler) under cyclic train loading, the indoor consolidated undrained dynamic triaxial tests were carried out. The effect of granular rubber content, confining pressure and loading frequency on the shear modulus and damping ratio characteristics of the granular rubber-sand mixtures were studied. The results showed that when the shear strain was constant, the shear modulus decreased with the increase of granular rubber content or loading frequency, and increased with the increase of confining pressure. Based on the Hardin-Drnevichin hyperbolic law, the shear modulus test results were fitted to obtain the maximum shear modulus, which decreased with the increase of granular rubber content. When the shear strain was constant, the damping ratio of the granular rubber-sand mixtures increased with the increase of granular rubber content, and decreased with the increase of confining pressure. Based on the experimental results, the relationship between damping ratio and shear strain was established. In addition, based on the micro contact characteristics of flexible rubber particles and rigid sand particles, the influence mechanism of granular rubber on shear modulus and damping ratio of the mixtures was analyzed. According to the research results, the highest granular rubber content in the new subgrade filler was 20%. When the granular rubber content was lower than 20%, the new subgrade filler, whose dynamic shear modulus can meet the requirements and damping ratio was relatively large, had a good damping and energy dissipation effect.
文章编号:202000011     中图分类号:U414    文献标志码:
基金项目:国家自然科学基金项目(51608533);中国铁路总公司科技研究开发计划(2017G008-A)
作者简介:丁瑜(1990-),女,博士生.研究方向:路基动力学.E-mail:ding_yu@csu.edu.cn
引用文本:
丁瑜,张家生,陈晓斌,王晅,贾羽,闫鹏.橡胶颗粒-砂混合物新型路基填料动力参数特性的试验研究[J].工程科学与技术,2020,52(5):170-177.
DING Yu,ZHANG Jiasheng,CHEN Xiaobin,WANG Xuan,JIA Yu,YAN Peng.Experimental Study on Dynamic Parameter Characteristics of New Subgrade Filler Composed of Granular Rubber-Sand Mixtures[J].Advanced Engineering Sciences,2020,52(5):170-177.