黄土-泥岩斜坡地震动响应结构效应及失稳机制研究

The slope structure with loess-mudstone-weak interlayer in the potential meizoseismal area is the origin of landslide susceptibility and geo-disasters. The dynamic response characteristics and failure mechanism of the special structured slope under earthquakes have not been systematically studied. In this project, the research target is the landslides induced by historical earthquakes in the northern part of West Qinling Mountains Loess Hilly Region. Field investigation is carried out to analysis the characteristic of the structured slope and its geo-disasters background in Loess Hilly Region and to extract the loess slope type and disaster mode. Based on the special soil dynamic tests, the vibrating damage law of the Loess-mudstone contact surface and the soft interlayer is studied, the vibration weakening criterion of these two kinds of structures is constructed, and the mechanism of vibration weakening is revealed from the micro view. With the physical simulation and numerical simulation methods, considering the different internal and external dynamic conditions, it is possible to reproduce the dynamics response and deformation process of the special structured loess slope. Also, the transient dynamics response of the loess slope and the structural effect are studied, and the influence factor of the seismic response of the slope structure are determined. The control effect of loess-mudstone contact surface and mudstone soft interlayer on slope instability under seismic load is analyzed. Then the instability mechanism of earthquake motion on loess-mudstone-soft interlayer slope is discussed. This paper aims to establish quantitative evaluation criteria for earthquake induced slope failure and to provide a theoretical basis for the early identification and early warning of this kind of loess landslide.

位于潜在强震区黄土-泥岩-软弱夹层结构的斜坡是滑坡易发性和灾难性的根源，这类特殊斜坡结构在地震作用下的响应特征和破坏机理尚未得到系统研究。本项目以西秦岭北缘黄土丘陵区历史地震滑坡为导向，开展野外调查，剖析黄土丘陵区斜坡结构的特殊性及其孕灾环境背景，提炼黄土斜坡类型和成灾模式。基于特殊土动力学试验，研究黄土-泥岩接触面及软弱夹层的震动损伤规律，构建这两类结构面的震动劣化准则，并从微细观角度揭示其震动弱化机理。借助物理模拟和数值模拟方法，考虑不同内外动力条件，重现特殊结构黄土斜坡地震动响应至变形的过程，探索黄土斜坡地震动瞬态响应规律及其诱发的结构效应，确定斜坡结构地震动反应的影响因子。分析地震荷载作用下黄土-泥岩接触面及泥岩软弱夹层对斜坡失稳的控制作用，探讨黄土-泥岩+软弱夹层斜坡的地震动失稳机制，以期建立量化评判标准，为这类地震黄土滑坡的早期识别和预警提供理论依据。

位于潜在强震区黄土-泥岩-软弱夹层结构的斜坡是滑坡易发性和灾难性的根源，这类特殊斜坡结构在地震作用下的响应特征和破坏机理亟待开展深入研究。本项目以西秦岭北缘黄土丘陵区历史地震滑坡为导向，开展了野外调查，剖析了黄土丘陵区斜坡结构的特殊性及其孕灾环境背景，提炼了黄土斜坡类型和成灾模式。基于特殊土动力学试验，研究了黄土-泥岩接触面及软弱夹层的震动损伤规律，构建了这两类结构面的震动劣化准则，并从微细观角度揭示了其震动弱化机理。借助了数值模拟方法，考虑不同内外动力条件，重现了特殊结构黄土斜坡地震动响应至变形的过程，探索了黄土斜坡地震动瞬态响应规律及其诱发的结构效应，确定了斜坡结构地震动反应的影响因子。分析了地震荷载作用下黄土-泥岩接触面及泥岩软弱夹层对斜坡失稳的控制作用，探讨了黄土-泥岩+软弱夹层斜坡的地震动失稳机制。研究成果能为这类地震黄土滑坡的早期识别和预警提供理论依据。