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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。
A series of stress-controlled bidirectional coupling cyclic shear tests under unequal consolidation conditions were carried out for undisturbed saturated marine soft clay from the Yellow River Delta. Emphasis was placed on the effects of initial principal stress direction angle α0, cyclic shear load component The effect of R and cyclic stress levels (indicated by the cyclic stress ratio Rc) on the residual deformation behavior of saturated marine clay. The experimental results show that the residual axial strain εr, the εr and the residual axial strain ratio of α0 during cyclic shear decrease gradually. Corresponding to the same N / Nf, the value of εr / εrmax firstly increases and then decreases with the decrease of R value. After the test data are normalized, the curves of εr / εrmax-N / Nf corresponding to different R values are concentrated in a narrow band and can be expressed by a unified expression. When α0 = 0 ° and 90 °, the difference of the residual shear strain γr-cycle number N corresponding to different R values is not very obvious. When α0 = 30 ° and 60 °, R has a significant effect on the γr-N relationship. The variation of εr and γr with the increase of N under low stress and high stress level is obvious, and the corresponding expressions of εr / εrmax-N / Nf are proposed respectively.