摘要
以黑龙江黏土为研究对象,按照3种不同的路径(干湿—冻融路径、冻融—干湿路径、交叉的干湿冻融路径)施加了温湿作用,对比分析了不同温湿路径下压实黏土的微观结构、土-水特性、累积塑性应变(ε_(p))和回弹模量(MR)的演化规律。结果表明:①温湿作用后土体内宏观孔隙发育,微观孔隙收缩,持水能力降低,脱湿速率增大。多次温湿作用后,经不同温湿路径的试样具有相似的微观孔隙结构及土-水特性;②ε_(p)和M_(R)在高含水率下对湿度变化(包括含水率w和吸力s)更敏感。冻融循环后,ε_(p)对湿度的敏感性显著增加,MR对湿度的敏感性显著降低;③温湿作用后土体的M_(R-s)关系呈现非线性特征,M_(R-w)关系呈现线性特征。长期温湿作用后,不同温湿路径对ε_(p)和MR的影响差异较小;④基于非饱和土力学原理建立模型,较好地预测了不同温湿路径下MR随湿度的变化规律。
The microstructure,soil-water characteristics,accumulative plastic strain(ε_(p))and resilient modulus(M_(R))of a compacted Heilongjiang clay are compared.The specimens are imposed with three different moisture(wetting-drying,WD)and temperature(freeze-thaw,FT)paths(i.e.,WD-FT,FT-WD and interlaced FTWD histories).The experimental results show that:(1)After moisture-temperature(M-T)actions,the structural pores develop while the textural ones shrink,which leads to reduction in the water retention capacity and increase in the desaturation rate.After M-T effects are stabilized,the microstructure and soil-water characteristics of the specimens with different M-T paths become similar.(2)Under at high moisture content(w),ep and M_(R)are more sensitive to moisture changes(including w and suction s).After FT cycles,ε_(p)becomes more sensitive while M_(R)becomes less sensitive to moisture changes.(3)After M-T effects,the M_(R)-s relationships are nonlinear while the M_(R)-w relationships are linear.The different M-T paths do not generate differences inep and M_(R)when the M-T effects are stabilized.(4)A model based on the mechanics of unsaturated soils is used to rationally predict the variation of M_(R)with w and s for the specimens with different M-T paths.
作者
韩仲
张琳
丁鲁强
邹维列
冯怀平
应镇谦
HAN Zhong;ZHANG Lin;DING Luqiang;ZOU Weilie;FENG Huaiping;YING Zhenqian(School of Civil Engineering,Wuhan University,Wuhan 430072,China;School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2024年第12期2591-2601,共11页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(52378365,52308346)
中央引导地方科技发展资金项目(236Z5409G)
中国博士后科学基金项目(2022M720986)。
关键词
压实黏土
温湿路径
动力响应
土-水特性
微观结构
compacted clay
moisture and temperature path
dynamic response
soil-water characteristic
micro structure
