复杂应力条件下原状饱和海洋黏土残余变形特性试验研究  

Experimental study of characteristics of residual deformation of undisturbed saturated marine clay under complex stress conditions

作　　者：刘功勋[1,2] 栾茂田[2] 唐小微[2] 邵琪[2] 张俊峰[2] 

机构地区：[1]中交上海航道勘察设计研究院有限公司中交疏浚技术重点实验室,上海200120 [2]大连理工大学土木工程学院岩土工程研究所,辽宁大连116024

出　　处：《岩土力学》2011年第7期1931-1938,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金重点基金资助项目(No.50639010);国家自然科学基金资助项目(No.51079018;No.50779003)

摘　　要：针对取自黄河三角洲地区的原状饱和海洋软黏土,进行了一系列非均等固结条件下的应力控制式双向耦合循环剪切试验,着重探讨了初始大主应力方向角α0、循环剪切荷载分量比R以及循环应力水平(用循环应力比Rc来表示)对饱和海洋黏土残余变形特性的影响。试验结果表明,α0对循环剪切过程中产生的残余轴向应变εr、破坏时的εr以及残余轴向应变比渐减小。对应相同N/Nf,随着R值减小,εr/εrmax值先增大后减小。试验数据经归一化处理后,不同R值对应的εr/εrmax-N/Nf关系曲线集中于一个狭窄的条带内,可用统一的表达式来表示。α0=0°与90°时,不同R值对应的残余剪应变γr–循环次数N关系曲线差异性并不十分明显,而α0=30°与60°时,R对γr-N关系影响显著。低应力与高应力水平循环荷载作用下εr与γr随N的增加变化规律差异性明显,分别建议了相应的εr/εrmax-N/Nf关系表达式。Through a series of stress-controlled bi-directional cyclic shear tests under different three-dimensional anisotropic consolidation stress conditions on the undisturbed saturated marine soft clay from the yellow river delta area, the effects of the initial orientation angle of the maximum principal stress α0, the ratio of the two stress components R and the cyclic stress level （expressed by cyclic stress ratio Re） on the characteristics of residual deformation of the saturated marine clay are examined. The test results show that the α0 has remarkable effect on the residual axial strain er caused by cyclic loading, εr at failure and the relation between ratio of residual axial strain ετ/εmax and ratio of number of cycles N/Nf. Both εr caused by cyclic loading and εr at failure decrease with a decrease of R. At the same N/Nf, ετ/εmax increases at first then decreases with a decrease of R. The relation curves of ετ/εmax -N/Nf with different R concentrate in a narrow strip and can be expressed by a unified expression by normalizing the test data. At α0 =0° and 90°, the differences of relation curves between residual shear strain γr and cycle number N with different values of R are not remarkable. While at or0 =30° and 60°, the R has significant influence on the relation curves between γr andN. The differences of the variation regularities of ετand γr under low stress level and high stress level with an increase of N are obvious. The relational expressions between ετ/εmax and N/Nf are proposed.

关 键 词：原状饱和黏土 三向非均等固结 双向耦合循环剪切 主应力轴持续旋转 循环应力水平 残余变形 

分 类 号：TU411[建筑科学—岩土工程]