高陡岩质边坡岩桥的脆性剪断机理及定量评价

Stability control of Large rock slope is the urgent problem of science and technology in the engineering geology field. For the slip, tensile crack and shear failure of large rock slope, The "brittle failure" of rock bridge which play critical controlling role in the "three stages pattern" deformation model is taken as the research object for rock slope in this project..At first, centrifugal model test is carried out to simulate the "three stages pattern" landslide failure, and the experienced complex stress path of the rock bridge can be got in the slope failure process. The test is focus on the multi-scale test(true triaxial test, AE testing and SEM observation) for the rock bridge on the complex stress path, The brittle failure and dynamic energy evolution rule of the rock bridge can be revealed in the failure process of rock slope. And on this basis, the mechanical model that can describe the plastic-brittle failure of the the rock landslide is proposed, scientific simulation method of the quantitative analysis for large rock landslide disaster is established. Finally, the large rock slopes of hydropower engineering in southwest China are taken as the example to validate and perfect the above theory..The reveal of brittle failure mechanism of rock bridge and the establishment of quantitative evaluation method can provide the precious early warning time for the landslide prevention and people evacuation. The research results provide basic theory for studying large rock slope stability which is based on the deformation controlling.

大型岩质边坡稳定性控制是工程地质领域迫切需要解决的科学技术问题。针对大型岩质边坡的滑移-拉裂-剪断"三段式"失稳破坏问题，本项目以"三段式"岩质边坡变形模式中具有关键控制作用的岩桥"脆性破坏"为研究对象。首先开展模拟"三段式"滑坡形成的离心模型试验，获得岩桥在滑坡失稳中经历的复杂应力路径，重点开展在此应力路径下岩桥多尺度试验（真三轴试验、AE测试和SEM观察），针对性地揭示边坡失稳过程中岩桥的脆性破坏及能量动态演化规律；在此基础上，提出能描述三段式岩质滑坡塑性-脆性破坏的力学模型，建立大型岩质滑坡灾害定量分析的科学仿真方法；最后，以西南大型水电工程岩质高边坡为背景，验证和完善上述理论。岩桥脆性破坏机理的揭示和定理评价方法的建立可为滑坡灾害防治和人员及时撤离提供宝贵的预警时间，研究成果将为基于变形控制的大型岩质边坡稳定性研究提供基础性理论依据。

滑移-拉裂-剪断“三段式”岩质边坡的失稳破坏问题，是我国西南典型的地质灾害问题，大量的工程实践表明中部岩桥呈现明显的脆性破坏特征。本项目以“三段式”岩质边坡变形模式中具有关键控制作用的岩桥“脆性破坏”为研究对象。首先开展模拟“三段式”滑坡形成的物理模型试验，获得岩桥在滑坡失稳中经历的复杂应力路径，重点开展在此应力路径下岩桥直剪试验、常规三轴加载和加卸载试验和真三轴试验，针对性地揭示边坡失稳过程中岩桥的脆性破坏及能量动态演化规律；在此基础上，提出能描述三段式岩质滑坡塑性-脆性破坏的力学公式，建立大型岩质滑坡灾害定量分析的科学仿真方法；最后，以西南地区的大岗山水电工程岩质高边坡为背景，验证和完善了上述理论。.本项目深入揭示了岩桥内部破裂的应力、变形和能量演化机制，以及岩质边坡内部的破坏机理，阐明了岩质边坡破坏能量大、滑动距离远，引发巨大灾害的内在原因。先后提出了基于瑞典条分-软化理论的边坡稳定性评价方法，基于动态和整体强度折减法的边坡动态稳定性评价方法，发表SCI论文10篇，EI论文10篇，中文核心期刊7篇，授权相关专利5项，申请软件登记2项。研究成果应用于拉西瓦水电站、锦屏二级水电站、丹巴滑坡和大岗山水电边坡工程，解决了岩体变形预警、潜在滑动面识别等一系列重大工程技术难题，该项目的成果自2013年发表后，年平均引用达50余次，已累积引用200余次，其中SCI他引21次。论文《基于动态和整体强度折减法的边坡稳定性分析》入选“领跑者5000中国精品科技期刊顶尖学术论文”。本项目的成果对于岩质滑坡灾害的预测预警研究具有重要的科学意义，也能服务和应用于我国西南地区重大地质灾害预报工作。