砂土液化后液-固相变机理的单元试验与模拟

Mechanical Behavior and Theoretical Simulation of Post-Liquefied Sand in Fluid-Solid Transition Process

摘要:

液化后砂土流动是一个涉及液相向固相转化的过程。针对目前常规三轴加载模式在进行松砂液化后性质研究中存在局限性的现状，提出应力与应变控制相结合的加载方法，获取初始液化状态，开展液化后松散土体流态化性质研究。基于试验结果，引入液?固相变参数，耦合流体本构与固体本构关系，建立可统一描述液化后土体应力应变关系的经验模型，实现不同密实度条件下砂土液化后液?固相变转化全过程力学行为的模拟。

关键词:液化后砂土;液‒固相变;三轴试验;本构模型

Abstract:

Post-liquefied sand flow involves a phase transition process from fluid to solid. To overcome the limitation of normal triaxial loading mode for loose sand， a two-staged loading method， stress- and strain-controlled loading， was applied to obtain the initial liquefaction state and investigate the mechanical behavior in the post-liquefaction process. Based on test results， a fluid-solid transition parameter was proposed to combine solid and fluid constitutive models. Finally， the stress-strain relation of post-liquefied sand was established to simulate the fluid-solid transition process at different relative densities.

Key words:post-liquefied sand;fluid-solid transition;triaxial test;constitutive model