RESEARCH ON THE SAFETY EVALUATION AND RELIABILITY DESIGN AGAINST WAVE ACTION FOR ARMOR BLOCK BREAK WATER

本研究旨在通过室内试验研究碎石（块）溃决水可靠度分析的可能性。破水模型放置在1/30的底坡上。它的前后面斜率都是4/3。该模型由24.5g（平均）的碎石组成。实验采用周期波T=1.0s和1.4s（波周期），波高H=5-20cm（波高）的周期波来测量波浪作用下防波堤表面剖面的变化。这些变化用放置在波浪槽一侧的摄像机记录下来。使用计算机的叠加功能对记录进行分析。在波浪作用开始时，剖面变化非常快。然而，它逐渐减小，并最终停止，当剖面达到“稳定的s形剖面”。剖面变化公式为S=c_0+c_1EXP (-c_2n)，其中c_0， c_1， c_2为常数，n为作用波数。在本研究中，还对剖面形状进行了建模。在相同的波高和周期条件下，通过重复实验得到以n为单位的给定波高和周期条件下的期望斜率曲线。将预期波廓线与瑞利波高分布连接起来，以n为单位计算预期波廓线变化。从本研究的结果可以看出，在块体溃坝稳定性模型研究中，有可能进行3级可靠度分析。

This study aims at studying the possibility of reliability analysis for a rubble (block) break water through laboratory experiments. The break water model is placed on a bottom slope of 1/30. Its fore- and back surface slopes are both 4/3. The model is composed of crashed stones with 24.5g (average). Periodic waves with T=1.0s and 1.4s (wave period), and H=5-20cm (wave height) are used in the experiments to measure the surface profile changes of the breakwater against wave actions. The changes are recorded with the video camera placed side of the wave tank. The records are analyzed using the super-impose function of a computer. The profile change is very quick in the beggining of the wave actions. However, it reduces gradually and stops finally when the profile reaches to the "stable S-shape profile". The profile changes are formulated in the form of S=c_0+c_1EXP (-c_2n), where c_0, c_1, c_2 are constants and n is the number of waves acted. The shape of profile are also modeled in this study. Expected slope profiles for given conditions of wave height and period in terms of n are obtained through repeated experiments with the same wave height and period. Connecting the expected wave profiles with the Rayleigh wave height distribution, the expected profile changes are calculated in terms of n. From results of this study a possibility of the reliability analysis of the level 3 is shown in a model study of a stability of block break water.