The experimental data dealing with the so-called small strain stiffness of soils are indispensable in developing and calibrating advanced numerical models. A literature review revealed a lack of such data for unsaturated soils. In this study, the laboratory measurements of very small and small strain stiffness are carried out in a double-walled triaxial cell using bender elements and LVDT transducers. The tested soil is a reconstituted silty clay, representing a typical soil encountered in engineering practice. A so-called effective stress for unsaturated soil is used in interpreting and numerically simulating the effects of suction magnitude, net stress magnitude and suction history on the initial elastic shear modulus, and on its decrease with increasing strain. The increase of both net stress and suction leads to increase in stiffness. This is observed by both elastic shear modulus and shear modulus reduction curve measurements. The “overconsolidation” by suction leads to the increase of stiffness, too. The experimental data are used for calibrating constitutive parameters and for assessing the capabilities of an advanced hypoplastic model for unsaturated soils. The model predictions are consistent with the laboratory measurements and the model can capture the increase of stiffness with respect to the increase of suction and net stress reasonably well. Moreover, the model is able to predict the increase of stiffness due to suction “overconsolidation”.

在开发和校准高级数值模型中，处理所谓的土壤小应变刚度的实验数据是必不可少的。文献综述表明，对于非饱和土壤缺乏此类数据。在这项研究中，使用弯曲元件和LVDT换能器在双壁三轴单元中对很小和很小的应变刚度进行了实验室测量。所测试的土壤是再生的粉质粘土，代表了工程实践中遇到的典型土壤。所谓的非饱和土壤有效应力用于解释和数值模拟吸力大小，净应力大小和吸力历史对初始弹性剪切模量以及随应变增加而减小的影响。净应力和吸力的增加导致刚度的增加。通过弹性剪切模量和剪切模量降低曲线的测量都可以观察到这一点。吸力的“过度固结”也导致刚度的增加。实验数据用于校准本构参数，并用于评估非饱和土壤高级塑性模型的能力。该模型预测与实验室测量结果一致，并且该模型可以很好地捕获相对于吸力和净应力的增加所产生的刚度增加。此外，该模型能够预测由于吸力“过度固结”而导致的刚度增加。实验数据用于校准本构参数，并用于评估非饱和土壤高级塑性模型的能力。该模型预测与实验室测量结果一致，并且该模型可以很好地捕获相对于吸力和净应力的增加所产生的刚度增加。此外，该模型能够预测由于吸力“过度固结”而导致的刚度增加。实验数据用于校准本构参数，并用于评估非饱和土壤高级塑性模型的能力。该模型预测与实验室测量结果一致，并且该模型可以很好地捕获相对于吸力和净应力的增加所产生的刚度增加。此外，该模型能够预测由于吸力“过度固结”而导致的刚度增加。