基础理论与实验研究

基于微观力学机制的各向异性结构性砂土的本构模型研究

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  • 1. 同济大学 土木工程学院 地下建筑与工程系,上海 200092;2. 同济大学 土木工程防灾减灾国家重点实验室,上海 200092
蒋明镜,男,1965年生,教授,博士生导师,主要从事天然结构性黏土、砂土、非饱和土、太空土和深海能源土宏微观试验、本构模型和数值分析方面的研究工作。

收稿日期: 2014-12-01

  网络出版日期: 2018-06-09

基金资助

国家自然科学基金重点项目(No.51639008);国家杰出青年科学基金项目(No.51025932);长江学者及创新团队发展计划资助项目(No.IRT1029)。

A constitutive model for anisotropic structured sandy soil based on micromechanical mechanism

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  • 1. Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China; 2. State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai, 200092, China

Received date: 2014-12-01

  Online published: 2018-06-09

Supported by

This work was supported by the Key Program of National Natural Science Foundation of China (51639008), the National Science Foundation for Distinguished Young Scholars (51025932) and the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (IRT1029).

摘要

在岩土破损力学基础上,基于微观破损机制,提出了考虑各向异性的结构性砂土本构理论。采用Lade-Duncan强度准则考虑中主应力对抗剪强度的影响;采用考虑颗粒排列组构的各向异性状态变量A反映各向异性对土体强度和变形的影响;通过相似扩大重塑土的屈服面反映结构性对土性的影响;通过引入非相关联流动法则考虑各向异性和结构性对土体塑性变形的影响。同时,将基于微观力学机制的损伤演化规律引入结构性土的硬化规律;该硬化规律同时考虑了塑性体积应变和剪切应变对各向异性结构性土强度的影响。然后将该模型用于模拟室内三轴压缩试验,初步验证了该模型的合理性和适用性。

本文引用格式

蒋明镜,周 卫,刘静德,李 涛, . 基于微观力学机制的各向异性结构性砂土的本构模型研究[J]. 岩土力学, 2016 , 37(12) : 3347 -3355 . DOI: 10.16285/j.rsm.2016.12.001

Abstract

Based on the framework of damage mechanics for geological materials, a constitutive model is proposed for anisotropic structured sandy soils considering the micromechanism of the destructuring. The Lade-Duncan failure criterion is adopted to consider the effect of intermediate principal stress on the shear strength. An anisotropic state variable A considering the fabric of particle arrangement is employed to reflect the influence of the anisotropy on the mechanical behavior of structured soil. The influence of soil structure on the mechanical behaviors is considered by enlarging the structural yielding surface for reconstituted soils in geometry. The non-associated flow rule is applied to describe a reasonable plastic strain for the anisotropic structured soil. A damage law based on the debonding effect on microscale is used to model the soil destructuring in the hardening law for structured soils. The effect of both plastic volumetric strain and shear strain is considered in the hardening law. Thus, this model can properly describe the mechanical behaviors of soils from intact state to reconstituted state. The proposed model is preliminarily verified by predicting the mechanical behaviors of natural and artificially cemented sands in the triaxial tests.
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