K0固结结构性软黏土的旋转硬化规律研究

Rotational hardening law of K0 consolidated structured soft clays

从Wheeler等S-CLAY1本构模型出发,在软黏土结构性和塑性各向异性性状前期研究成果的基础上,综合考虑软黏土的塑性各向异性、结构性及其演化规律,将传统本构模型发展为更适用于K0固结结构性软黏土的本构模型。在考虑土体结构性及其演化的基础上,进一步研究土体塑性各向异性及其演化规律,引入旋转极限曲线的概念,通过增加一个表征软黏土各向异性演化速率的参数b,分析旋转硬化对K0固结结构性软黏土受力变形性状的影响,各向异性的初始值则可由常规试验参数获得。选取典型的浙江温州软黏土和Bothkennar软黏土,对比K0固结三轴压缩和三轴拉伸的计算和试验结果,揭示结构性软黏土屈服面旋转硬化的规律,同时对旋转演化速率参数的取值方法和取值范围进行研究。

Anisotropic plasticity and structure, together with their evolution laws were considered based on Wheeler＇s S-CLAY1 model. The traditional constitutive model was developed to fit for K0 consolidated structured soft clays, consistent with the author＇s previous works. The rotational limit line was introduced to the rotational hardening law and a parameter b was added to the model to reflect the evolution of anisotropy. The effect of rotational hardening on the behavior of K0 consolidated structured soft clays was analyzed and the initial value of anisotropic parameter could be obtained from the common laboratory tests. Two typical soft clays, Whenzhou clay and Bothkennar clay, were chosen to be calculated under tiaxial conditions. The importance of the rotational behavior of yield surface was indicated by the comparison of the calculated and tested results. At the same time the method to obtain the parameter b as well as its range was also dicussed.