基于摩擦动力学的地震滑坡产状分布特征形成机理及其预测方法研究

Research of distribution characteristics of the landslides triggered by Wenchuan earthquake, Lushan Earthquake and Ludian Earthquake showed a coupling effect of slope-unit occurrence (orientation and inclination), lithology and strata acceleration on the advantage of occurrence of earthquake-induced landslides. However, its dynamic mechanism has still not been demonstrated. We aim to explore the friction dynamic mechanism of landslide occurrence distribution phenomenon on the seismic excitation. In this research, a model shaking table experiment will be carried out, with seismic signals from Zoushishan and Songpan seismic stations recorded during the Wenchuan earthquake as input, to analyze the impact on the landslide seismic response for sliding surface friction characteristics and determine the relationship between seismic excitation, sliding surface friction characteristics and landslide dynamic response, to propose a dynamic friction model and evolution equations which contain occurrence of earthquake-induced landslides to analyze landslide seismic response, landslide initiation and its evolution, to reveal the dynamic mechanism of occurrence distribution of earthquake-induced landslides and to explore the prediction method, which will lay a solid scientific foundation for disaster prevention and mitigation planning of earthquake-induced landslides.

汶川、芦山和鲁甸地震导致的区域滑坡分布特征的研究表明，地震滑坡的优势产状与所在的斜坡产状（倾向和倾角）、岩性、地层加速度有关，但其动力学作用机理尚未十分明确。本课题旨在探索地震激励下，滑坡产状分布的摩擦动力学机制及其预测方法。拟以汶川地震郫县走石山和松潘两个台站的地震波为激励，进行振动台滑坡动力学模拟试验，分析滑动面摩擦特性对滑体地震响应的影响，确定地震激励、滑动面摩擦特性和滑体动力响应的关系，构建包含地震滑坡产状的摩擦动力学模型和演化方程，分析滑体地震响应与滑坡启动条件和演化过程，揭示地震触发的滑坡产状分布特征的摩擦动力学机制并探索其预测方法，为制定和完善地震区滑坡防灾减灾规划提供科学基础。

我国是一个地质灾害频发的国家，尤其是西南地区，频繁的地震和强降雨往往会带来大量的滑坡等地质灾害。本项目基于动力作用下的滑坡的演化机理，构建了滑坡动力学模型和演化方程。基于层状泥质板岩边坡的原位直剪试验，分析研究了结构面抗剪强度特性。在通过原位试验与UDEC数值计算对比的基础上，通过数值分析从细观角度揭示了含泥结构面的抗剪力学特性和其渐进破坏机制以及夹层厚度对含泥结构面抗剪强度的影响。采用Pietruszczak-Mroz各向异性破坏准则来描述层状岩石强度的方向依赖性。在子午线平面上，通过引入各向异性变量来确定摩擦系数。在偏平面上，各向异性破坏面表现为Lode角的光滑形状函数。基于三轴试验来确定破坏准则的材料参数，从而提出利用PM各向异性准则预测特定层状岩石的各向异性强度。本研究基于遥感解译，野外调研等技术，基于地理信息技术平台多学科多技术融合技术研究了西南地区地震及降雨作用下的滑坡特性及产状分布规律。通过中等分辨率的陆地卫星（Landsat）图像，结合典型地段的SPOT-5高精度遥感数据，利用人机交互的方式进行室内解译和野外验证相结合，完成汶川、芦山和鲁甸地震区域滑坡解译，提炼地震滑坡产状。此外，本项目还构建了地震频发区域滑坡分布预测方法及其产状预测方法。基于大数据统计分析了1040例边坡和8800例的模拟边坡，构建了在役边坡整体安全稳定技术状况评定体系。