摘要
开展上海软黏土的宏微观三轴剪切试验,研究软黏土受荷状态下孔隙的演化特征。结果表明:局部变形在加荷初期就开始发生。随着荷载的增加,细碎团聚体增多,孔隙不断地扩展,生成大的贯通孔隙,孔隙定向排列明显,剪切带形成。微观结构参数与剪应力比呈非线性正相关关系,最大孔隙面积、孔隙比、孔隙各向异性率及分布分维数在受荷初期缓慢地增大,后期快速增大。应变为8%时,最大各向异性率达到0.68,最大孔隙比为1.96。剪切带附近的微观结构参数都大于带外值。在受荷过程中,土的微观结构发生劣化,软黏土变形过程分为损伤开始、损伤发展剪切带形成和土体破坏3阶段,微观结构的劣化与土的宏观力学特性紧密相联系。
Macroscopic and microscopic triaxial shearing experiments were carried out on Shanghai soft clay to study the evolution characteristics of pores under loading.The results show that local deformation occurs at the beginning of loading.With the increase of the loading,number of small aggregates increase,pores continually enlarge,interconnected pores occur,the pore orientation is obvious,and a shear band is formed.Microstructure parameters are nonlinearly positive to the shear stress ratio.The maximum pore area,void ratio,anisotropy ratio and fractal dimension of pores increase slowly at an initial loading stage,and then increase rapidly at the later stage.The maximum anisotropy ratio reaches 0.68 and void ratio is up to 1.96,when the axial stain is 8%.The microstructure parameters of shear band are larger than those outside the band.During the triaxial loading,soil microstructure deteriorates and the whole deformation process of soft clay is divided into three stages:damage initiation,damage developing and shear band formation,as well as soil failure.Microstructure degradation is closely related to macroscopic mechanical properties of soil.
作者
孙红
宋春雨
滕慕薇
葛修润
SUN Hong;SONG Chun-yu;TENG Mu-wei;GE Xiu-run(School of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第1期141-146,共6页
Rock and Soil Mechanics
基金
国家自然科学基金项目（No.41572255,No.51678361）~~
关键词
软黏土
场发射电子扫描电镜
剪切带
孔隙
分形维数
soft clay
field emission scanning electron microscope(FESEM)
shear band
pore
fractal dimension
