摘要
级配呈现过渡特征的土被称为过渡土.路基填料中过渡型细粒土的击实特性不同,且力学性能受基质吸力的影响较大.根据试验标准(ASTM D698-12),进行标准击实试验,得到最优含水率和最大干密度.对试验土样,分别使用露点水势仪和高量程吸力计量测击实前后土样的基质吸力.结果表明:过渡土中黏粒含量的增加使路基填土压实特性不同,过渡土的最大干密度随着黏粒含量的增加而减小,过渡土的最优含水率随着黏粒含量的增加而增大;在击实曲线湿侧时击实土的基质吸力接近于0;击实后过渡土的基质吸力呈现过渡特征,当认为过渡土中的水分被黏粒完全吸收后,过渡土的吸力-含水率可以拟合为一条曲线,即吸力-黏土含水率曲线;在压实前的松散土颗粒的吸力量测中,也得到近似的试验结果.
Soil with transitional gradation is called transitional soil.The compaction characteristics of transitional fine-grained soil in subgrade filler are different,and its mechanical properties are greatly affected by matric suction.According to the standard ASTM D698-12,the standard compaction test was carried out,and the optimum water content(OWC)and the maximum dry density(ρdmax)were obtained.For each sample,the suction of compacted soil was measured using a dew-point water potential instrument(WP4C)and a high-capacity tensiometer(HCT)before and after compaction.The results show that the increase of the clay content in the transitional soil makes the compaction characteristics of the subgrade different.The maximum dry density decreases with the increase of clay content,and the optimum water content increases with the increase of clay content.When the water content of the wet side of the compaction curve is greater than OWC,the matric suction of compacted soil is close to zero.The matric suction of transitional soil also presents transitional characteristics.When the water in transitional soil is completely absorbed by clay particles,the suction-water content of transitional soil can be fitted as a curve of suction-water content of clay.The same results were obtained in the suction measurements of loose soil particles before compaction.
作者
张炎飞
刘先峰
袁胜洋
陈伟志
ZHANG Yanfei;LIU Xianfeng;YUAN Shengyang;CHEN Weizhi(Key Laboratory of High-Speed Railway Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Xinjiang Institute of Engineering,Urumqi 830023,China;China Railway Eryuan Engineering Group Co.Ltd,Chengdu 610031,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2023年第4期935-945,共11页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(52168066,52078432)
四川省科技计划项目(2019YFSY0015)
中铁二院工程集团有限责任公司科研项目(科2018-61)。
关键词
道路工程
击实试验
击实特性
过渡型细粒土
基质吸力
非饱和土力学
土水特征曲线
road engineering
compaction test
compaction characteristics
transitional fine-grained soil
matric suction
unsaturated soil mechanics
soil water characteristic curve
作者简介
张炎飞(1992-),男,博士研究生.E-mail:zhangyanfei@my.swjtu.edu.cn;通信作者:刘先峰(1980-),男,博士,教授.E-mail:xianfeng.liu@swjtu.edu.cn。
