湿地湖泊相黏土应力-应变及屈服特性试验  

Experimental study on stress-strain behavior and yield characteristics ofmarshy and lacustrine clay

作　　者：朱楠 张静娟 刘春原 ZHU Nan;ZHANG Jingjuan;LIU Chunyuan(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China;Civil Engineering Technology Research Center of Hebei Province,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]河北省土木工程技术研究中心,天津300401

出　　处：《哈尔滨工业大学学报》2020年第11期183-191,共9页Journal of Harbin Institute of Technology

基　　金：河北省科技计划项目(15273802D);河北省交通运输厅科技计划项目(Y-2012004)。

摘　　要：为探讨结构性和各向异性影响下湿地湖泊相黏土的应力-应变特性和屈服特性,分析结构性和应力路径对湿地湖泊相黏土应力-应变关系的影响,基于应力路径试验系统研究湿地湖泊相黏土的屈服特性.结果表明:湿地湖泊相黏土的应力-应变特性受胶结和组构的显著影响,当土体球应力增量大于0时,胶结和组构共同承担荷载,能提高土体的抗压强度并减小压缩变形;当土体球应力增量小于0时,组构不能承受拉应力,仅有胶结承担荷载,胶结能够提高土体承受拉应力的能力并产生较大的膨胀变形.由于不同应力路径下湿地湖泊相黏土均受球应力和偏应力的交互影响,导致其应变方向与应力路径方向存在一定偏差,但塑性应变增量与屈服轨迹却存在较好的正交性,可以采用相关联法则描述塑性流动特性.最后,由于受沉积时的K 0固结和胶结影响,湿地湖泊相黏土的屈服轨迹为一旋转椭圆形,并和临界状态线一起与p′轴交于q-p′平面原点左侧.To investigate the stress-strain behavior and yield characteristics of marshy and lacustrine clay under the influences of soil structure and anisotropy,the effects of soil structure and stress path on stress-strain behavior of marshy and lacustrine clay were analyzed,and the yield characteristics of marshy and lacustrine clay were systemically studied by means of stress path tests.Results show that the stress-strain behavior of marshy and lacustrine clay was significantly affected by bonding and fabric of soil.When the soil was in a stress path under positive mean effective stress increments,bonding and fabric of soil bore the mean effective stress together,which improved the compressive strength of the soil and reduced the compressive deformation.When the soil was in a stress path under negative mean effective stress increments,fabric could not bear the tensile stress and only bonding bore the tensile stress,which improved the ability of soil to bear tensile stress and produced large expansion deformation.Due to the interaction between mean effective stress and deviatoric stress under different stress paths,there was a little difference between the orientations of strain and stress paths.However,since there was a good orthogonality between plastic strain increment and yield loci,the correlation flow rule could be used for marshy and lacustrine clay.Finally,the yield loci of marshy and lacustrine clay was a rotating and distorting ellipse,which intersected to the p′axial on the left of the origin of q-p′plane along with the critical state line,because of the effects of K 0 consolidation and bonding during sedimentation.

关 键 词：湿地湖泊相黏土 应力-应变特性 应力路径试验 屈服面 结构性 

分 类 号：TU442[建筑科学—岩土工程]