粘性土剪切带与屈服应力的探讨-水利水运工程学报.PDFVIP

第2期 水 利 水 运 工 程 学 报 No.2 摇 2008年6月 HYDRO鄄SCIENCE AND ENGINEERING Jun. 2008 粘性土剪切带与屈服应力的探讨 1,2 1 2 李苏春 , 蒋摇 刚 , 雷秋生 (1. 南京工业大学 土木工程学院, 江苏 南京摇 210009;2. 江苏省纺织工业设计研究院有限公司, 江苏 苏州摇 215001) 摘要:利用全自动三轴仪,对南京地区典型的粉土、粉质粘土试样进行了固结不排水剪试验,研究具有剪切带 性状试样的孔隙水压力随偏应力的变化关系,分析屈服应力、孔隙水压力和土体分叉之间的关系.试验结果表 明,孔隙水压力的峰值可以表征土体局部开始屈服,并出现应变局部化的状态.围压的增大会延迟土体分叉,而 干密度较大时易出现剪切带.可用土体初始分叉点来确定土体的强度参数. 关摇 键摇 词:剪切带;屈服;分叉;孔隙水压力 中图分类号:TU442摇 摇 摇 摇 文献标识码:A摇 摇 摇 摇 文章编号:1009-640X(2008)02-0089-05 An exploration of shear band of cohesive soils and yield stress 1,2 1 2 LI Su鄄chun , JIANG Gang , LEI Qiu鄄sheng (1. Collegeof CivilEngineering,Nanjing University of Technology,Nanjing摇 210009,China;2. SuzhouBranch, JiangsuProvince Textile Industry Design and Research Co郾 ,Ltd郾 ,Suzhou摇 215001,China) Abstract:The undrained shear tests of Nanjing silty and silty clay were conducted by the KTG to investigate relationships between pore water pressure and deviator of specimens with shear band,and to analyze yield stress and pore water pressure and soil bifurcation. The experimental analysis shows that water pressure peak can illuminate the state when some districts in soil begin to yield and deformation localization occurs. The soil bifurcation will be delayed as the confiningpressure increases. But shear band isapt to come inthe specimenwith high dry density. The strength parameters can be determined by onset of soil bifurcation. Key words:shear band;yield stress;bifurcation;pore water pressure 与其它工程材料一样,土具有应力-应变特性和屈服特性.当土体某一微小区域满足屈服条件时,便开 [1-3] 始产生塑性应变 .随着应力的增加,薄层区域内的变形相对较大,而区域外的变形相对较小,随之土体出