降雨-地震共同作用下加筋土挡墙变形破坏演化机理及设计方法研究

加筋土挡墙良好的抗震性能已被广泛认同。历史震例表明：地震与降雨常相伴而生，其共同作用会削弱加筋土结构稳定性并引发次生灾害，对其进行深入研究需重点关注降雨-地震共同作用下非饱和填土的力学特性，即固、液、气三相之间动力耦合作用。本项目旨在探索降雨-地震共同作用下加筋土挡墙变形破坏演化机理及其设计方法。首先，通过大尺寸静/动三轴试验获取加筋土填土的应力-应变关系；继而探寻能够真实反映填土静/动力学行为的本构表征参数及其发展函数，建立饱和•非饱和填土统一静/动力本构模型，并将其导入数值计算程序中对工程实例进行数值分析；最后，结合足尺振动台试验和数值分析结果，揭示降雨-地震共同作用下加筋土挡墙变形演化规律及破坏机理，并提出可考虑降雨作用的加筋土挡墙动力设计计算方法。其研究成果不仅为加筋土挡墙的风险评估提供科学依据，而且为控制加筋土挡墙变形确保其稳定性提供技术支撑，同时还可完善现有加筋土结构设计理论。

It has been widely recognized that geosynthetic reinforced soil retaining walls (GRS-RWs) have good seismic performance. Previous research has shown that earthquakes and rainfall often occur together, their combined effect will decrease the stability of reinforced soil structures and trigger secondary disaster. In order to study it in-depth, the mechanical properties of unsaturated filling under rainfall-earthquake combined effect need to be focused, namely, the dynamic coupling effect between soil particles, water and air. This project aims to explore deformation and failure mechanism of GRS-RWs under rainfall-earthquake combined effect, and establish a corresponding dynamic design and calculation method. First, large-scale static/dynamic triaxial tests are employed to reveal the stress-strain relationship and deformation characteristics of the filling. Then apparent parameters and their development function, which can truly reflect the static /dynamic behavior of the filling, will be confirmed. On this basis, a unified saturated-unsaturated filling static/dynamic constitutive model can be established thereafter, which will be imported to a numerical analysis program to model real engineering cases. Finally, full-scale shaking table tests and numerical simulation will be carried out to reveal the evolution mechanism of deformation and failure of GRS-RWs under rainfall-earthquake combined effect, and a design and calculation method that can properly assess the dynamic response of GRS-RWs under considering the rainfall effect will be established. The research results can not only provide scientific evidence for the risk assessment of GRS-RWs, but also can provide technical support for controlling the deformation of GRS-RWs, meanwhile, existing design theories of reinforced soil structures can be improved as well.