饱和盐渍土分数阶蠕变模型及试验研究

采用等温条件下饱和盐渍土的固结蠕变试验研究了其蠕变特性。在元件模型的基础上，通过引入Abel阻尼器和渗透吸力后，建立了饱和盐渍土的分数阶蠕变模型，从表观现象学方面展开了含盐量与饱和盐渍土蠕变特性的相关性讨论。结合试验结果和分数阶模型，拟合分析了渗透吸力同次固结系数与压缩指数的比值 和初始剪切模量以及初始剪切应变的相互作用关系。在蠕变试验的基础上，通过不同应力水平、含盐量的试验结果对分数阶模型进行了拟合分析，并结合给出的黏度系数公式对模型的有效性进行了验证。分析结果表明：次固结系数与压缩指数的比值 随着渗透吸力的增大而增大且呈指数关系，初始剪切模量随着渗透吸力的增大而减小，初始剪切应变与渗透吸力呈现出线性关系。相比与整数阶元件模型，所提出的分数阶蠕变模型更适合于饱和盐渍土蠕变行为的预测。结合试验和模型分析结果，发现含盐量的增大促进了盐渍土的蠕变行为。

Fractional creep model and experimental study of saturated saline soil

The creep behaviors of saturated saline soil are studied in the consolidation creep test under isothermal conditions in this paper. Based on the element model, the fractional creep model of saturated saline soil was established by introducing Abel dashpot and osmotic suction. The phenomenological correlation between salt content and creep behavior of saturated saline soil is discussed. The effects of osmotic suction on the ratio of the secondary compression coefficient to the compression index, initial shear modulus and initial shear strain are analyzed by combining experimental results with fractional model fitting. The fractional order model is fitted by the test results of different stress levels and salt content. The validity of the model is verified by the viscosity coefficient formula. The results show that the ratio increases exponentially as the osmotic suction increases. The initial shear modulus decreases as the osmotic suction increases, and the initial shear strain exhibits a linear relationship with the osmotic suction. Comparing with the integer element model, the fractional creep model proposed in this paper is more suitable for predicting the creep behavior of saturated saline soil. Combined with the results of experiments and model analysis, it is found that the increase of salt content promotes the creep behavior of saline soil.