基于触发式黏塑性元件的黏性土黏弹塑性动本构模型  

Viscoelastic-plastic dynamic constitutive model of cohesive soil based on triggered viscoplastic element

作　　者：赵程斌 骆亚生[1] 范全 孟智田 孙哲 ZHAO Cheng-bin;LUO Ya-sheng;FAN Quan;MENG Zhi-tian;SUN Zhe(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《岩土力学》2024年第2期502-510,524,共10页Rock and Soil Mechanics

基　　金：陕西省自然科学基础研究计划(No.2021JLM-51)。

摘　　要：基于黏性、弹性和塑性元件构造的动本构模型往往存在预测效果较差,不能完全反映黏性土的黏性、弹性、塑性的缺点。通过引入一种触发式的黏塑性元件Ψ,以残余变形为切入点,提出了一个考虑振动稳定和振动衰化现象的黏性土黏弹塑性动本构模型,并通过动三轴试验进行了验证。该动本构模型不但能够描述动荷载作用下黏性土残余应变的发展规律,且能合理地预测动应变的发展情况。结果表明,试样在动荷载作用下,存在元件Ψ的黏滞系数随振动周期增长而衰减的现象,且衰减情况和含水率密切相关。最优含水率是影响振动稳定和振动衰化现象的重要参数,当含水率小于最优含水率时,试样变形表现为振动稳定,此时元件Ψ黏滞系数的变化可以忽略不计;当含水率大于最优含水率时,试样变形表现为振动衰化,此时元件Ψ黏滞系数的变化不可忽略。The dynamic constitutive models based on viscous,elastic,and plastic elements often suffer from poor prediction performance and fail to fully capture the viscous,elastic,and plastic characteristics of cohesive soil.To address these limitations,a viscoelastic-plastic constitutive model for cohesive soil is proposed in this study by introducing a triggered viscoplastic element(symbolized as Ψ) and considering residual deformation as a starting point.The model takes into account the phenomena of vibration stability and vibration decay and is validated through dynamic triaxial shear tests.This dynamic constitutive model not only describes the development pattern of residual strain in cohesive soil under dynamic loads but also provides reasonable predictions for dynamic strain development.The results indicate that the viscosity coefficient of the Ψ element decays as the vibration period increases,and this attenuation is closely related to the moisture content under dynamic loading conditions.The optimal moisture content serves as an important parameter that influences both vibration stability and vibration decay.When the moisture content is less than the optimal moisture content,the deformation of the sample exhibits vibration stability,and the change of the viscosity coefficient can be ignored.When the moisture content is greater than the optimal moisture content,the deformation of the sample exhibits vibration decay,and the change of the viscosity coefficient cannot be neglected.

关 键 词：触发式黏塑性元件 残余变形 振动稳定 振动衰化 黏弹塑性动本构模型 

分 类 号：TU435[建筑科学—岩土工程]