Abstract Sandy soils produced from offshore engineering and dredging activities usually possess a fine fraction beyond the “transitional fine content”. The soils have a wide range initial water content and sand fraction. Previous models based on mixture theory is not straightforward, and the effect of initial water content is not explicitly incorporated. To this end, a novel compression model is formulated by incorporating the equivalent void ratio into the tangent stiffness of clay matrix. The virgin compression behavior of clay matrix is captured by incorporating two physical variables, termed as the reference void ratio and the remolded yield stress, which are correlated with the initial water content of the clay matrix. The equivalent void ratio concept is then introduced by incorporating a structure variable which relies uniquely on the volume fraction of sand. The structure variable denotes the sand fraction effect linking to partial contacts and densified clay bridges between aggregates. It relies on basic features of sand, e.g., the particle shape and particle size distribution. Morphological analysis reveals that the model is versatile to capture the two basic features of the sandy clays, e.g., the increasing compressibility and decreasing remolded yield stress with rising initial void ratio of clay matrix, the sand fraction effect arising from the partial contacts and clay bridges between aggregates. The proposed model has five material constants, and only three oedometer tests are required for the calibrating these parameters. Validation of the model reveals that the model is effective to reproduce the compression behavior of sandy soils with a wide range of initial void ratio and sand fraction.

中文翻译：

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基于等效孔隙比概念考虑砂分效应的砂质粘土压缩行为估算

摘要 海洋工程和疏浚活动产生的砂质土壤通常具有超出“过渡细粒含量”的细粒部分。土壤具有广泛的初始含水量和沙子比例。以前基于混合物理论的模型并不简单，初始含水量的影响也没有明确纳入。为此，通过将等效空隙比纳入粘土基体的切线刚度，建立了一种新的压缩模型。粘土基质的原始压缩行为通过结合两个物理变量来捕获，称为参考空隙比和重塑屈服应力，它们与粘土基质的初始含水量相关。然后通过结合唯一依赖于砂的体积分数的结构变量来引入等效孔隙比概念。结构变量表示与骨料之间的部分接触和致密粘土桥相关的砂粒分数效应。它依赖于沙子的基本特征，例如颗粒形状和粒度分布。形态学分析表明，该模型可以通用地捕捉砂质粘土的两个基本特征，例如，随着粘土基体初始孔隙率的增加，压缩性增加和重塑屈服应力降低，部分接触和粘土桥引起的砂分效应聚合体之间。所提出的模型有五个材料常数，校准这些参数只需要三个固结仪测试。