【摘要】 已有的液化砂土流动特性试验结果表明,砂土在液化流动状态下是剪切稀化非牛顿流体,可以用幂函数表示其剪应力-剪应变率的关系,从而建立了砂土液化流动的本构方程。基于FLAC3D程序的二次开发平台,将液化流动本构方程开发到FLAC3D中,建立了液化流动变形的简化分析方法。通过倾斜场地的液化流动变形分析,发现倾斜场地的液化变形曲线可以用正弦函数曲线描述,这与Towhata的理论分析成果一致,验证了本方法的合理性。分析了液化层坡度、稠度系数、流动指数以及弹性参数等变量对液化变形的影响。计算结果表明,液化变形随液化层坡度的增大而逐渐增大,液化砂土的稠度系数和流动指数对液化流动变形有重要的影响,而弹性参数对变形基本无影响,因此,在实际工程分析中,需要对流动模型参数进行深入研究。更多还原

【Abstract】 Previous research on liquefaction flow characteristic indicates that liquefied sand can be modeled as shear thinning non-Newtonian fluid.Aflow constitutive equation of liquefied sand is established by using a power function relationship between the shear stress and the shear strain rate.A simplified method for large deformation analysis of liquefied sand is established through implementing the flow constitutive equation into the FLAC3D package.Acase study of gradient foundation is performed by applying the proposed method to validate the constitutive model.The numerical results show that the displacement of gradient foundation can be described by a sinusoidal curve,which is in good agreement with the theoretical solution of Prof.Towhata.Parametric sensitivity analyses are conducted to investigate the influences on the deformation of liquefied sand from variables including the liquefaction layer slope,consistency coefficient,flow index and elastic parameters.The results indicate that the liquefaction deformation develops with the increase of the slope of the liquefied layer.What’s more,the consistency coefficient and the flow index of the liquefied sand have significant effect on the deformation of liquefied sand;while influence from the elastic parameters is inconsiderable.A further research on these parameters should be conducted in engineering practice.更多还原