极限荷载下平顶楔体破坏机理的非线性能耗分析方法与试验研究

项目名称： 极限荷载下平顶楔体破坏机理的非线性能耗分析方法与试验研究

项目编号： No.51478477

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 赵炼恒

作者单位： 中南大学

项目金额： 72万元

中文摘要： 平顶楔体极限荷载问题是岩土塑性理论中的基本问题，地基承载力、土压力和边坡承载力均可归结为该问题。传统的不考虑土体重度、界面摩擦和材料非线性特点的分析方法，为避免数学求解的困难而忽视了材料的有重和非线性自然本质，导致计算结果与实际偏差较大，是土工构筑物设计面临的主要困境之一。本课题充分利用能量法物理意义明确、解答严格有效、便于引入材料非线性特性获得直观破坏模式的特点，深入研究极限荷载下平顶楔体非线性失稳机理的几个基础性问题：提出基于滑移线场理论的有重土二维完整上限速度场构建方法；建立通用非线性破坏准则条件下平顶楔体极限荷载问题的非线性能量耗散模型，揭示内外非线性能耗效应共同作用下平顶楔体破坏的演化机理；同时采用模型试验和数值仿真与理论结果对比验证；最后开展拓展应用研究，开发便于工程应用的可视化程序包。项目研究可以完善岩土塑性理论的研究内容，为工程实际中土工构筑物灾变评估提供理论依据。

中文关键词： 平顶楔体；极限荷载；非线性能耗模型；滑移线场理论；非线性规划

英文摘要： The ultimate load of flat wedge is the basic problem in geotechnical plasticity theory, including the soil pressure, bearing capacity of foundations and slope. Although the weightness and nonlinear feature of geomaterials is a well-known fact, the traditional methods have neglected it due to the complexity of theoretical solution. This design way is the main reason lead to the unmatched in features between calculation results with the engineering practice, hence the traditional methods could not guarantee a satisfactory design. The limit analysis approach has the characteristics of clear physical meaning, strict and effective solutions and easy to introduce the geotechnical nonlinear material properties. In addition, it can directly apply the nonlinear programming method to obtain the critical failure state of the rock mass in instability region without gradation loading. Therefore, this topic adopts this method to study several basic problems of the nonlinear failure mechanism for flat wedge under the ultimate load. Through the research, the complete 2d upper limit velocity field building method is put forward based on the theory of slip line field. According to the general nonlinear failure criteria of the geotechnical material, the nonlinear energy dissipation model of geotechnical ultimate load is established, and thus gets the failure mode of flat wedge and internal energy dissipation distribution, thereby reveals the failure mechanism of flat wedge under the common action of internal and external nonlinear energy dissipation. Finally, adopting model test and finite element simulation to compare with the theoretical results, and then carrying out expanding research on the basis of this study. This project will broaden the geotechnical plastic mechanics research field and content from theoretical system, and provide solid theoretical basis for geotechnical structure disaster assessment and prevention in practical engineering.

英文关键词： flat wedge;ultimate load;nonlinear energy model;slip line theroy;nonlinear programming