In this paper, a new approach is proposed to determine the undrained shear strength of intact clays using the undrained rigidity index inferred from piezocones and shear wave velocity measurements based on the theory of spherical cavity expansion. The derived cone factors are further simplified for young, uncemented (non-structured) clays to be solely expressed in terms of the cone behaviour type index. Moreover, an empirical expression is suggested to relate the undrained shear strength of fissured clays to the cone and shear wave measurements. The proposed approach is used to assess the values of undrained shear strengths in several well-reported test sites. The estimated strengths are found to be in a good agreement with the related field and laboratory measurements in intact clays, whereas in fissured clays, the estimated undrained strengths are shown to match less favourably with the laboratory measurements. This may be attributed to the strong dependence of the undrained shear strength of such clays on the site-specific orientations and properties of the prevailing fissures.

中文翻译：

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使用压电锥和剪切波测量进行不排水的剪切强度评估

本文提出了一种新方法，该方法可以根据压电锥的不排水刚度指数和基于球形腔膨胀理论的剪切波速度测量来确定完整黏土的不排水抗剪强度。对于年轻的，未胶结的（非结构化）粘土，可以进一步简化派生的圆锥系数，仅根据圆锥行为类型指数来表示。此外，提出了一个经验表达式，将裂隙粘土的不排水抗剪强度与圆锥波和剪切波测量值相关联。所提出的方法用于评估几个报告良好的测试位置中不排水的剪切强度的值。发现完整黏土的估计强度与相关领域和实验室测量值非常吻合，而在裂隙黏土中，估计的不排水强度与实验室测量值的匹配度较差。这可能归因于这种粘土的不排水抗剪强度强烈依赖于主要裂缝的特定位置取向和性质。