As a frequent occurring geomorphological process characterized by high energy and mobility, the rockfall movement is the basis of the disaster prediction and mitigation. In this study, the kinematic evolution behaviors of rockfalls are investigated using three-dimensional discontinuous deformation analysis (3D DDA) based on block kinematics. A series of field experiments are designed by orthogonal experimental method to study the block movement considering the influence of the slope angle, the characteristics of the block itself and the initial falling conditions. Selecting the combination of factors that have the most significant influence on the block movement, the 3D DDA numerical model is established and the effectiveness of 3D DDA is verified by comparing the displacement and kinetic energy evolutions obtained by experiments. Then, the 3D DDA is applied to simulate the rockfalls of Wangxia slope in Chongqing, and the kinematic evolutions of the entire rockfall processes are further studied by analyzing the rock mass instability and the movement trajectory and kinetic energy evolutions of blocks. The experimental results show that slope angle has the greatest influence on block kinematics, followed by block mass, falling height, block shape and falling angle. In the practical slope analysis, the rockfall processes consist of sliding failure, oblique projectile movement, flying over or colliding with the highway, and flying away from the slope, showing 3D movement characteristics due to lateral translation and rotation. The rockfall kinematic evolutions induce slope disasters to the highway, and pose a threat to shipping in Yangtze River channel. The 3D DDA method can quantitatively analyze the failure of dangerous rock masses and the kinematic evolutions of rockfalls after instability, which is helpful to provide revealing insights into the rockfall disaster processes and mechanisms.

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3D DDA 现场实验验证及其在落石运动学演化中的应用

落石运动作为一种频繁发生、具有高能量、高流动性的地貌过程，是灾害预测和减灾的基础。在本研究中，利用基于块运动学的三维不连续变形分析（3D DDA）研究了落石的运动学演化行为。采用正交试验方法设计了一系列现场试验，综合考虑坡度角度、块体本身特性和初始下落条件的影响，研究块体运动。选择对块体运动影响最显着的因素组合，建立3D DDA数值模型，并通过比较实验获得的位移和动能演化来验证3D DDA的有效性。然后，应用3D DDA对重庆望峡斜坡落石进行模拟，通过分析岩体失稳以及块体的运动轨迹和动能演化，进一步研究整个落石过程的运动学演化。实验结果表明，倾斜角度对块体运动学影响最大，其次是块体质量、下落高度、块体形状和下落角度。在实际边坡分析中，落石过程包括滑动破坏、斜抛射运动、飞越或碰撞公路、飞离边坡等，表现出由于横向平移和旋转而产生的3D运动特征。落石运动演化对高速公路造成边坡灾害，并对长江航道航运构成威胁。 3D DDA方法可以定量分析危岩体的破坏和失稳后落石的运动学演化，有助于揭示落石灾害过程和机制。