土工合成加筋砂土地基加载速率相关的时变特性研究

项目名称： 土工合成加筋砂土地基加载速率相关的时变特性研究

项目编号： No.51279132

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 水利工程

项目作者： 彭芳乐

作者单位： 同济大学

项目金额： 80万元

中文摘要： 与钢筋混凝土基础或挡土结构相比，土工合成加筋土复合地基无疑是一种相对柔软的土工构筑物。因此，施工时的瞬时变形及使用时的长期流变是土工合成加筋土设计上必须考虑的重要参数。实际工程监测表明加筋土的荷载沉降曲线与加载速率显著相关，这种特性严重影响加筋土地基的短期或长期与时间有关的变形行为，而以时间t为内在变量的传统粘塑性理论和流变模型不能完全合理解释这种现象。本项目以土工格栅加筋砂土为对象，基于加载速率变化开展一系列的模型试验和理论研究，分析加载速率变化与加筋砂土地基与时间相关变形的关系及内在规律。本项目的创新点主要包括：阐明加载速率变化下加筋砂土瞬时及长期变形发生机理；提出基于加载速率效应的加筋砂土时间有关变形的有限元预测方法。本项目的研究方法将突破直接以时间t为内变量的传统弹粘塑性理论框架，其成果对揭示加筋砂土与时间相关的变形破坏机理以及确立高精度的变形预测方法具有重要的理论意义及应用价值。

中文关键词： 砂土；土工合成加筋材料；加载速率效应；蠕变；应力松弛

英文摘要： Compared to RC basements and structures, the geosynthetic-reinforced soil is undoubtedly a relatively soft basement or structure, thus the deformation control must be seriously considered in the design of th geosynthetic-reinforced soil, which includes the instantaneous deformation following construction and the long-term residual deformation after construction.The obvious loading rate-dependent behaviors of geosynthetic-reinforced soils are observed in the field measurement of actual engineering project, namely, on a step-change in the loading rate, the basement pressure-settlement relation is changed correspondingly. It is due to the viscous properties of the backfill and the geosynthetic-reinforcement and the interactions between them. The above behaviors seriously affect the short-term deformation following construction and the long-term residual deformation after construction. Although it is time-dependent, the traditional rheological theory and model with the state parameter of time(t), cannot interpret the deformation behaviors of geosynthetic-reinforced soil under the change of loading rate. In the present study,therefore, a series of model tests of the geogrid-reinforced sands under the change loading rate will be performed in order to analyze the relationship between the loading rate and the tim

英文关键词： sands；geosynthetic reinforcements；loading rate effects；creep；stress relaxation