不排水条件下基坑卸荷土体变形机理研究(Ⅰ)  

An mechanism study of excavation soilmass deformability of unloading under undrainage (Ⅰ)

作　　者：赵鑫[1] 陈学军[2] 李晓红[3] 朱志政[4] 

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074 [2]桂林理工大学土木工程系,广西桂林541004 [3]广西水利电力职业技术学院机电工程系,广西南宁530023 [4]湖北工业大学土木与建筑学院,湖北武汉430068

出　　处：《四川建筑科学研究》2010年第5期117-119,共3页Sichuan Building Science

基　　金：广西建筑工程检测与试验重点实验室基金课题(桂科能07109005-B)

摘　　要：在真三轴仪上模拟基坑开挖周边土体的应力路径,进行了不排水条件下卸荷与加荷两种试验,通过试验结果的对比分析可知,土体在不同应力路径下应力—应变关系有着显著的差异,说明应力路径条件对土体的变形有着一定的影响。进一步研究了不排水条件下卸荷土体广义剪应力与广义剪应变的关系,证明土体广义剪应力与广义剪应变关系曲线呈明显的非线性,并根据偏应力不变量推导出了土体卸荷剪切模量计算公式。The stress-path of the soilmass surrounding the periphery of a foundation pit project during excavation is simulated using a true triaxial unit; and two kinds of undrainage tests are conducted under loading and unloading conditions respectively. It can be known from the comparison between the testing results that there is a remarkable difference in the stress-strain relationship of the soilmass provided the stress-path conditions are different,which shows that the stress-path condition has an effect to a certain degree on the soilmass＇s deformability. Further studies are conducted on the relationship between generalized shear stress and generalized shear strain under undrainage conditions during unloading,the results showing the nonlinear relationship of those strain and stress. Finally,the equation to calculated the soil＇s unloading shear modulus is deduced when the invariant of deviatoric stress is given.

关 键 词：不排水条件 卸荷土体 变形机理 真三轴 偏应力不变量 

分 类 号：TU41[建筑科学—岩土工程]