路基非饱和土抗剪强度的吸力效应  

Matric Suction Effect on Shear Strength of Roadbed Unsaturated Soil

作　　者：刘东燕[1] 郑志明[1,2] 侯龙[1,3] 赵宝云[1] 伍川生[1] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆市公路局,重庆401147 [3]美国科罗拉多矿业大学,戈尔登80401

出　　处：《土木建筑与环境工程》2012年第4期1-5,18,共6页Journal of Civil,Architectural & Environment Engineering

基　　金：交通部西部交通建设科技项目(2009318000001)

摘　　要：从宏观的吸力控制型直剪试验和微观的土体颗粒结构2方面入手,对路基非饱和土抗剪强度的吸力效应进行了研究。在不同吸力和不同法向应力条件下完成4组剪切试验,并选取2种不同含水量的同类型土样进行结构扫描。研究结果表明,与粘性土不同的是,当粉质砂土含水量逐渐降低时,土体基质吸力对土体抗剪强度的贡献效果并不是一直增加的,而是存在一个峰值。这种现象主要是由于土体微观结构以及所含水分的存在形式所造成的。另外,土体所处的应力环境也会对土体强度的吸力贡献情况造成影响。A study which focuses on the role of matric suction in the stress strength of roadbed unsaturated soil was presented.Two types of tests were described,namely,the suction-controlled shear test and microstructure scanned test.For the former,four sub-tests were conducted under different suction and net normal stress conditions.And two unsaturated soil samples that belong to the same type but with different water contents were scanned.In contrast with clay soil,the corresponding results show that the strength of silty sand soil does not always increase as matric suction increases or soil water content decreases;there exists a peak contributed by matric suction that acts on soil stress strength.The main reason for this kind of phenomenon is due to the typical microstructure of this type of soil and the various types of pore water retention.Additionally,the state of stress in which soil sample meets can also exerts important influence on soil strength.

关 键 词：路基非饱和土 宏微观方法 吸力效应 气-液交界面 弯月形水膜 

分 类 号：U416.14[交通运输工程—道路与铁道工程]