Flip buckets are among one of the most common types of energy dissipaters, especially for dams. The scouring phenomenon occurs when falling jets hit the river bed, and A-Jack concrete block armors can be used as an effective way to control such a phenomenon. The main purpose of this study is to investigate the stability of sediment particles using A-Jack concrete block armors. In this regard, the general form of the incipient motion and incipient failure of A-Jack armor were extracted based on dimensional analysis and particle stability analysis. In these analyses, the dimensionless parameter of stability number denoted by SN is a function of other variables. The results of different physical models for different hydraulic conditions and sediment sizes are evaluated. Variability of SN related to each variable is considered, and linear and non-linear models for prediction of breakage conditions of the A-Jack block are derived. Using the experimental results, several empirical relations were developed to predict the incipient motion and incipient failure for different protection alternatives under different conditions of A-Jack block. By defining the bed scour as a criterion for the stability of A-Jack block, a design relation was also proposed to determine the required block size. Other topics investigated and discussed in this paper include effects of size and type of A-jacks as well as criteria for a gravel filter.

翻转铲斗是最常见的耗能器之一，尤其是在大坝中。当坠落的喷射器撞击河床时会发生擦洗现象，并且可以使用A-Jack混凝土砌块装甲作为控制这种现象的有效方法。这项研究的主要目的是研究使用A-Jack混凝土砌块装甲的沉积物颗粒的稳定性。在这方面，基于尺寸分析和颗粒稳定性分析，提取了A-Jack装甲的初期运动和初期破坏的一般形式。在这些分析中，由SN表示的稳定性数的无量纲参数是其他变量的函数。评估了不同水力条件和沉积物尺寸的不同物理模型的结果。考虑与每个变量相关的SN的可变性，推导了用于预测A-Jack块破损情况的线性和非线性模型。利用实验结果，建立了几种经验关系，以预测在不同的A-Jack块条件下，不同保护替代方案的初期运动和初期失效。通过将床冲量定义为A-Jack砌块稳定性的标准，还提出了一种设计关系来确定所需的砌块大小。本文研究和讨论的其他主题包括A千斤顶的尺寸和类型的影响以及砾石过滤器的标准。建立了几种经验关系，以预测在不同的A-Jack块条件下，不同保护方案的初期运动和初期破坏。通过将床冲量定义为A-Jack砌块稳定性的标准，还提出了一种设计关系来确定所需的砌块大小。本文研究和讨论的其他主题包括A千斤顶的尺寸和类型的影响以及砾石过滤器的标准。建立了几种经验关系，以预测在不同的A-Jack块条件下，不同保护方案的初期运动和初期失效。通过将床冲量定义为A-Jack砌块稳定性的标准，还提出了一种设计关系来确定所需的砌块大小。本文研究和讨论的其他主题包括A千斤顶的尺寸和类型的影响以及砾石过滤器的标准。