三维加筋土结构稳定性分析与设计优化研究

Reinforced earth structures are widely used in China. The collapse of these projects causes serious damage of infrastructures, such as highway, railway and hydraulic engineering project, and even causes many casualties. In reality, the failure surfaces of reinforced earth structures are three-dimensional. However, the current stability analysis and design methods are still based on the traditional plane-strain assumption, ignoring the effects of 3D conditions. The 2D assumption has inevitable influence on the stability analysis and design of reinforced earth structures. Therefore, the 3D conditions need to be included. In this project, the 3D failure mechanism will be established in the framework of limit analysis, solving the problems in the current approaches of stability analysis and design of reinforced earth structures. Based on this 3D failure mechanism, a design optimization for non-uniform length of reinforcements will be presented. Besides, the effects of seismic loads and pore water pressure will be analyzed and verified by model tests. Finally, design charts will be given for the convenient design of three-dimensional reinforced earth structures or stability assessment. Comparing with the solutions under plane-strain conditions, the effects of three-dimensional conditions will be demonstrated. These results will enhance the stability analysis theory of reinforced earth structures and provide reliable suggestions for practice.

加筋土结构在我国应用广泛，这些工程一旦失稳将会造成公路、铁路、水利等设施的严重破坏，同时给人民生命财产带来重大损失。加筋土结构在真实的破坏形式上呈现三维空间特性，然而目前的稳定性分析和设计方法仍主要基于传统的平面应变假设，忽略了实际存在的三维空间效应。这会不可避免地影响加筋土结构的稳定性评价和设计，因此需要开展三维加筋土结构稳定性分析及其设计的研究。本项目将针对现有加筋土结构稳定性分析及设计中的不足，采用极限分析法构建三维破坏机制，并在此基础上进行加筋体的非均匀铺设设计优化方法研究，同时考虑地震作用和孔隙水压对加筋土结构稳定性的影响规律，并通过试验进行验证。最终绘制一系列稳定图用于三维加筋土结构的设计或快速评价其稳定性，通过与平面应变解对比，揭示三维空间效应对加筋土结构稳定性及其设计的影响规律。研究成果将丰富加筋土结构稳定性分析理论，同时对工程设计提供可靠的参考依据。

目前加筋土结构的稳定性分析方法仍是主要基于平面应变展开，这将对加筋土结构稳定性分析的真实性产生影响。采用三维分析能准确地评估加筋土结构的稳定性，为工程决策者制定合适的设计方案提供可靠的参考依据。本项目针对三维加筋土结构稳定性分析及设计研究中的不足，考虑实际加筋土结构的三维空间特性，基于极限分析法构建和完善了其三维破坏机制，在三维分析框架下建立了更加合理的加筋土结构优化设计方法，揭示了三维空间效应以及地震和孔隙水压对加筋土结构稳定性的影响规律。同时针对三维加筋土结构稳定性分析方法难以广泛应用的缺点，绘制了稳定图，能用于快速而准确地评价或设计加筋土结构。