饱和砂土液化后流体本构模型研究

利用空心圆柱扭剪仪开展了饱和南京细砂液化后常速率加载试验,考虑了有效固结压力和加载速率对饱和南京细砂液化后流体特性的影响,结果表明:液化后静加载过程中剪应力与孔压比的发展具有明显的二阶段特性,且剪应力与孔压比的发展有着良好的线性相关关系,有效围压及加载速率对二者的关系有着明显影响;据此提出一种符合液化后静加载过程的率相关性及孔压相关性流体本构模型,该模型将构成饱和砂土强度的土颗粒摩阻力与土–水黏滞阻力分别表示为时变型和非时变型剪切稀化流体;最后进行了该模型的验证性试验,并将模型预测结果与其他学者研究成果对比,验证试验及对比结果均表明该模型具有较好的适用性。

Constitutive model for fluid of post-liquefied sand

The static load tests on post-liquefied saturated Nanjing fine sand are carried out using the hollow cylinder apparatus. The effect of the initial effective confining pressure and loading rate on the fluid characteristics of post-liquefied saturated Nanjing fine sand is taken into account. The results show that the development process of the shear stress and pore water pressure ratio have obvious two-stage characteristics in static loading process, and they have a a good linear relationship. The effective confining pressure and the static loading rate have obvious influence on the relationship between them. On this basis, a constitutive model for fluid with rate and pore water pressure-dependent static loading process is proposed. In this model the friction resistance between soil particles and the viscous resistance between soil and water are respectively expressed as the thixotropic shear-thinning fluid and non-time-variant shear-thinning fluid. Finally, experiments and comparisons between the predicted curves and other researchers′test results are carried out, indicating that the proposed constitutive model has good applicability.