顺层岩质边坡“滑移-剪断”型失稳过程中的损伤演化机理研究

In this project, the "slip-shear" instability of bedding rock slopes is taken as the research object, and the damage evolution mechanism of bedding rock slopes during the process of "slip-shear" instability is studied by using the method of similar model experiment and numerical simulation. Firstly, similar experimental models for bedding rock slopes are established in the laboratory. The internal deformation, acoustic emission, cracks evolution and slope surface deformation of bedding rock slopes are monitored by means of distributed optical fiber, digital speckle, acoustic emission and laser displacement. The mechanical mechanism of slopes damage and instability caused by stress concentration, stress release and stress transfer in laboratory scale are revealed. Secondly, a numerical model of anisotropic damage-dominant direction evolution is established to simulate and interpret the mechanical mechanism of slope damage and failure instability at laboratory scale, and to inversely calculate the relevant parameters in the numerical model. Finally, the numerical model is applied to engineering slope to reveal the damage evolution mechanism of bedding rock slopes during "slip-shear" instability. The research results are of great theoretical significance for determining the sliding surface evolution of bedded rock slopes, early-warning information for bedded rock slopes hazard and design for bedded rock slopes reinforcement.

本项目以顺层岩质边坡的“滑移-剪断”型失稳为研究对象，采用相似模型实验和数值模拟相结合的方法，开展顺层岩质边坡“滑移-剪断”型失稳过程中的损伤演化机理研究。首先，开展顺层岩质边坡的相似模型实验，采取分布式光纤、数字散斑、声发射和激光位移相结合的监测手段，监测顺层岩质边坡内部变形、声发射及裂缝演化和坡表变形规律，揭示实验室尺度边坡内部应力集中、应力释放和应力转移诱发边坡损伤、破坏失稳的力学机制；其次，建立各向异性损伤-优势方位演化数值模型，模拟解译实验室尺度边坡损伤、破坏失稳力学机制，反算数值模型中的相关参数；最后，将该数值模型应用于工程实例边坡，揭示顺层岩质边坡“滑移-剪断”型失稳过程中的损伤演化机理。研究成果对于确定顺层岩质边坡滑移面演化、滑坡灾害预警及加固方案设计具有重要理论意义。

顺层岩质边坡失稳主要是沿着关键结构面滑动及其诱发的岩桥断裂，人们越来越重视“滑移-剪断”型边坡安全，特别是对层状岩层切向和法向刚度、强度变化引起的多层滑移、主滑移厚度与剪断启裂位置、扩展角度的变化规律尚不清楚，剪切应力变化诱发坡脚损伤区演化机理仍有待进一步明晰。本项目利用室内实验、数值模拟、原位监测试验及相应的理论分析方法，着重开展了顺层岩质边坡“滑移-剪断”型失稳过程中的损伤演化机理研究，主要研究成果体现在如下三个方面：（1）基于层状岩体各向异性波速场实验及理论分析，提出了基于各向异性波速场模型的声发射事件定位算法；（2）研究了顺层岩质边坡滑动面的启动、滑移及局部拉伸-剪断过程，揭示了顺层岩质边坡滑移-剪断型损伤破坏演化机制；（3）研究了开挖扰动作用下边坡岩体声发射/微震活动性分布规律，识别和圈定边坡深部岩体诱发的损伤区，建立了基于声发射/微震的顺层岩质边坡稳定性评价与预警方法。历时三年研究，本项目累计发表学术论文5篇（SCI收录5篇）、申请发明专利1项、获得省部级科技奖励1项。本项目的研究成果不仅对于确定顺层岩质边坡潜在滑移面、滑坡预测预警及加固方案具有重要意义，而且对于确定隐伏型顺层岩质边坡的极限高度、优化隐伏型顺层岩质边坡的最终边坡角也具有一定参考价值。