评价饱和砂土液化过程中小应变到大应变的本构模型(英文)

A constitutive model for evaluating small to large cyclic strains of saturated s and during liquefaction process

在RambergOsgood模型的基础上,建立了一个实用的能描述饱和砂土从液化前小应变到初始液化后大应变范围的非线性本构模型。该模型主要有三个特点:①采用作者曾提出的移动相态转换线(MPTL)和移动临界状态线(MCSL)概念来较为合理地描述变形过程中的有效应力路径和临界状态;②采用一个应力软化模型来描述剪胀和定义超静孔压变化引起的骨架曲线的软化与硬化;③基于笔者等提出的液化后大变形理论来描述初始液化后产生的大剪切变形。文中通过对室内循环剪切试验结果的模拟,验证了模型的预测能力。该模型适用于水平饱和砂土地基的有效应力地震反应分析。

A new simplified effective stress constitut ive model is presented for evaluating small to large cyclic strains of saturated sand dur ing liquefaction process.It is developed by refining and modifying Ramberg-Osg ood model in the following three aspects:①A formulation for asymptotic movement s of both MPTL(Moving Phase Transformation Line)and MCSL(Moving Critical Stat e Line)is incorporated to accurately describe the effective stress path and the critical stress state;②A stress degradation model is used to describe the stres s-dilatancy and to define the degradation and hardening of the skeleton curve w ith variation of excess pore water pressure;③A new post-liquefaction deformation theo ry is incorporated to model large shear strain response in cyclic undrained loading after initial liquefaction.The results calculated by the proposed model have been compared favorably with experimental observations.The new model is s uitable for dynamic response analysis of level or nearly level saturated sand gr ound.