针对上海软土统一本构模型不能模拟小应变情况下土体剪切模量的衰减特征问题，结合小应变下经典刚度理论对小应变范围内的上海软土统一本构模型进行改进，以使软土本构模型能够模拟土体在小应变下的刚度变化规律，并将模拟结果与上海浅层软土在小应变下的三轴剪切试验结果进行对比，以验证改进的软土本构模型的合理性.结果表明，改进的软土本构模型能够模拟小应变情况下土体较高的初始切变模量及其非线性衰减特征，并能够较好地表征自然黏土体的结构和超固结特性.
Although the Shanghai soil unified model can describe the influence of soil structure and over consolidation, it cannot simulate the highly nonlinear modulus in small strain range. In this paper, combined with the classical theory of small strain stiffness, a small strain constitutive model based on Shanghai soil unified model is developed. The small strain constitutive model can describe the change rule of soil stiffness in the small strain range. The capability of the model is checked by the triaxial compression test results on Shanghai shallow soil. The results show that small strain constitutive model can describe that soil stiffness in the small strain range has initial high modulus and the non-linear attenuation characteristics, and the influence of structure and over consolidation on soil can also be reproduce well by the model.
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