Due consideration of non-linear soil stiffness is one of the essential requisites in many geotechnical applications. A considerable amount of the geotechnical literature, as well as numerous recent studies, have been directed towards enhancing our ability to formulate mathematical relationships expressing the stiffness non-linearity of fine-grained soils and to determine the controlling parameters of such relationships. At present, the parameters of the non-linear clay stiffness formulations are commonly correlated to Atterberg's plasticity index (PI), even though this is obtained from testing remoulded samples, whereas the looked-for parameters are distinctly related to the undisturbed clay condition. In this paper, a new approach is proposed to establish the link between the non-linear stiffness parameters and the undrained rigidity index, as a more pertinent factor for the undisturbed compressibility of clays than the PI. The proposed approach was used to predict the undrained non-linear behaviour of several well-reported formations (London Clay, San Francisco Bay Mud, Skå-Edeby Clay and Hachirougata Clay). Good agreement between the predicted and the measured non-linear stiffnesses was found, implying that the presented methodology can be broadly applicable to different clay formations.

中文翻译：

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利用刚度指数评估黏土的不排水非线性刚度

适当考虑非线性土壤刚度是许多岩土工程应用中的基本要求之一。大量的岩土工程文献以及许多近期的研究都致力于提高我们建立表达细粒土刚度非线性的数学关系式以及确定这种关系的控制参数的能力。目前，非线性黏土刚度配方的参数通常与阿特伯格的可塑性指数（PI）相关，即使这是通过测试重塑样品获得的，而所寻找的参数则与未扰动的黏土条件明显相关。本文提出了一种新的方法来建立非线性刚度参数与不排水刚度指标之间的联系，与PI相比，它是黏土不受扰动压缩性的一个更相关的因素。所提出的方法被用来预测几个报告良好的地层（伦敦粘土，旧金山海湾泥，斯科德比粘土和八路加塔粘土）的不排水非线性行为。在预测的和测量的非线性刚度之间找到了很好的一致性，这意味着所提出的方法可以广泛地适用于不同的粘土地层。