基于扰动状态概念的结构性软土蠕变模型

摘要

Soil structural and creep characteristics influence soft soil behavior, therefore, it is necessary to establish models that may reflect the effects of the disturbance and structural breaking processes. The disturbed state concept defined by Desai is introduced, and a creep constitutive model of structural soft soil is established, in which the relative intact state is chosen to be represented by a three-element generalized Kelvin model and the fully adjusted state by a 3-D EVP model, and an empirical expression is employed as the disturbance function. From macroscopic test results and microstructure analysis, it is found that the disturbed state model can describe that structural soft soil gradual attenuation process under the stress in creep. Model parameters are obtained by isotropic compression test and triaxial creep test.The model is verified with one consolidated-undrained triaxial shear creep test of the Huangshi area soft soil.%结构性和蠕变性对软土工程性质具有双重影响,有必要建立一种模型能够准确描述扰动带来结构性逐步破损的过程并同时反映软土蠕变特性对地基变形的影响.引人扰动状态概念,选取三元件广义Kelvin模型描述相对完整状态,3D EVP模型描述完全调整状态,扰动函数采用经验表达式,建立了一个基于扰动状态概念的结构性软土蠕变模型.从宏观试验结果和微观结构变化分析,说明扰动模型可以很好地描述在应力作用下软土结构性在蠕变过程中逐渐衰减的过程.模型中的参数都可通过等向压缩蠕变试验与三轴蠕变试验获取.通过黄石地区的结构性软土的三轴固结不排水蠕变试验数据对模型进行检验,结果表明该模型能较好描述结构性软土的蠕变特性.