Experimental Study on Near-Field Characteristics of Impulse Waves Generated by Three-Dimensional Rock Slide
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摘要:
为了预测水库库岸滑坡入水后产生的冲击波(涌浪)到达承灾体的时间及立波高度,以水库岩体滑坡所诱发的冲击波为研究对象,对近场区涌浪的波场特征进行研究. 首先,根据弗劳德相似准则,并结合三峡库区典型岩体滑坡参数及其裂隙发育情况,建立碎裂岩体滑坡涌浪三维物理模型;其次,通过模型试验揭示了近场涌浪的产生机理及传播规律;最后,通过多元回归分析建立了近场涌浪预测模型. 研究结果表明:初始涌浪产生的主要驱动力是滑坡体对水体的置换和拖拽所致,其中初始波谷振幅大小主要取决于水面塌陷的持续时间;根据滑坡水下运动过程,引入两种临界水深,提出初始波谷产生时间的计算方法;初始波峰的传播速度与孤立波波速非常接近,而初始波谷、第二波波峰与波谷的传播速度则要小于孤立波波速,其无量纲相位波速分别为孤波波速的0.90倍、0.78倍、0.68倍.
Abstract:In order to predict the arrival time and wave height of the shock wave (surge) from a landslide source to the hazard-affected body, the near-field wave characteristics of the surge induced by the reservoir rock mass landslide were experimentally studied. Firstly, according to the typical rockslide parameters and rock fracture characteristics in the Three Gorges reservoir area, a three-dimensional physical laboratory model for cracked rockslide generated impulse waves was built based on the generalized Froude similarity. Then, the near-field wave generation mechanism and propagation law were revealed though model tests. Finally, a prediction model of near-field waves was established by multiple regression analysis. The results showed that the main driving force of the first wave is the displacement and drag of the landslide to the water body; the size of the leading wave trough amplitude depends on the duration of the water collapse. According to the underwater movement process of the landslide, two critical water depths are introduced in this paper, and the calculation method of the first wave trough generation time is proposed. Furthermore, the first wave crest propagates at velocities up to the approximate solitary wave celerity. The celerity of the first wave trough and the second wave is lower than that of the solitary wave, and their measureless phase wave speeds are 0.9, 0.78 and 0.68 times the solitary wave celerity, respectively.
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