粉砂-结构界面的剪切特性及多尺度本构关系

项目名称： 粉砂-结构界面的剪切特性及多尺度本构关系

项目编号： No.51508585

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑科学

项目作者： 周万欢

作者单位： 珠海澳大科技研究院

项目金额： 20万元

中文摘要： 研究土-结构接触面的力学特性是解决土与结构物相互作用问题的基础性研究。土体是散粒体材料，土-结构界面剪切过程伴随的颗粒滑移、转动、错位等微观现象是界面宏观剪切特性的根本原因。基于连续体理论的宏观模型本质上无法有效地从物理角度描述土-结构界面的力学和变形机制。本项目拟采用微观力学方法研究粉砂-结构界面剪切特性。在代表性单元内定义土颗粒间及土颗粒-结构接触面平均微观力学关系，即局部坐标下法向及切向力-位移关系。通过宏观坐标系下代表性单元内所有接触面方向的统计，积分得到界面宏观应力-应变关系，构建粉砂-光滑及粗糙界面多尺度本构关系。进行一系列粉砂-结构界面的排水剪切试验，考虑粉砂不同粒径范围，不同密实度，界面不同粗糙度等因素，研究粉砂-结构界面的剪切特性。界面剪切试验结果与多尺度本构关系模拟结果比较，验证模型的有效性和准确性。通过参数分析深入探讨微观参数对粉砂-结构界面的剪切特性的影响。

中文关键词： 土-结构界面；本构关系；多尺度模拟；界面粗糙度；微观力学

英文摘要： The Investigation of mechanical properties of soil-structure interface is a fundamental study for the interaction between soil and structures. Soil is an aggregate of particles. The soil-structure interface shearing is accompanied with particle slip, rotation, dislocation and other microscopic characteristics during the shearing process, which is the fundamental reason of the macro shearing properties of soil-structure interface. Existing macro interface models, which are based on the theory of continuum mechanics, are unable to effectively describe the nature of soil-structure interface shearing mechanism. This project aims to investigate the multi-scale constitutive modeling of silty sand-structure interface with the use of micro-mechanics approach. Based on the theory of contact mechanics, the average micro-mechanical relationship, i.e. the normal and tangential force-displacement relationship between soil particles and between soil particle - structure can be defined in a representative volume unit. The macro stress-strain relationship of silty sand-structure interface can be established by integrating all directions of the contact stiffness of the representative interface unit in the micro coordinate. Then the multi-scale constitutive relationships of silty sand- smooth/rough structure interface can be obtained. A series of interface direct shear tests between silty sand–structure will be conducted, taking into account different gradations of soil particles, initial dry density, roughness degree of the structure surface, etc., to investigate the shearing behavior of silty sand-structure interface. The new multi-scale constitutive relationships can be validated by comparing with the experimental results. Parametric analysis will be further performed to study the effect of micro parameters on the shearing characteristics of silty sand-structure interface.

英文关键词： Soil-Structural Interface;Constitutive Relationship;Multi-scale Modeling;Interface Roughness;Micromechanics