摘要
为深入了解软土蠕变机制,开展了上海淤泥质黏土的一维固结蠕变试验、结合水测试试验和扫描电镜(SEM)试验,定量分析了固结蠕变过程中结合水和微结构的分阶段变化规律。结果表明:p<σ_k时主要是自由水的排出,宏观表现为衰减蠕变过程;p>σ_k后,渗透结合水逐渐转化为自由水排出,蠕变变形和等速蠕变率明显增大。蠕变过程由渗透结合水主导,随着结合水排出土的结构逐渐固化,含水率随荷载增加呈指数型衰减,存在固结-蠕变耦合效应。松散的骨架-絮凝结构演变为紧密的团聚-絮凝结构,颗粒在经历了蠕变调整之后定向性降低,小孔隙数量大量增加,孔径<1μm的小孔隙组占优。存在荷载、结合水与颗粒的响应机制,其结果可以较好地解释工程现象。
To understand creep mechanism of soft clay, one-dimensional consolidation creep tests, bound water measurement tests, and scanning electron microscope（SEM） tests on Shanghai mucky clay are conducted. The variations of bound water and microstructure in the process of consolidation-creep are quantitatively analyzed. The results show that, free water discharged under condition of pσ_k during decaying creep process. The osmotic bound water is changed into free water to excrete under condition of pσ_k. Meanwhile, the creep strain and steady-state creep strain rate increase significantly. The creep process is dominated by osmotic bound water. The microstructure is solidified gradually with bound water discharging and the water content decreases exponentially with increasing loads. Deformation of soft clay is caused by consolidation-creep coupling effects. The original loose skeleton-flocculated structure translates into dense reunion-flocculated structure. The directionality of particles decreases under the long-term creep adjustment. The quantity of fine pores increases massively after creep tests and the pores with diameters less than 1 μm in dominancy. The response mechanism among loads, bound water and particles can explain engineering phenomenon well.
作者
李硕
王常明
吴谦
张志敏
张兆楠
LI Shuo WANG Chang-mingl WU Qian ZHANG Zhi-minl ZHANG Zhao-nan(College of Construction Engineering, Jilin University, Changchun, Jilin 130026, China Highway College, Chang＇an University, Xi＇an, Shaanxi 710064, China No.272 Geological Party of Nuclear Industry, Nanjing, Jiangsu 210003, China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2017年第10期2809-2816,共8页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41572257)~~
关键词
软土
固结蠕变
结合水
微结构
蠕变机制
soft soil
consolidation-creep
bound water
microstructure
creep mechanism
