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

本文通过室内试验研究了抛石（块）防波堤可靠度分析的可能性。防波堤模型放置在1/30的底部坡度上。其前后表面坡度均为4/3。模型由平均24.5g的碎石组成。试验采用T=1.0s和1.4s（波周期），H=5- 20 cm（波高）的周期波，测量了防波堤在波浪作用下的表面轮廓变化。这些变化是用放置在波浪槽一侧的摄像机记录的。利用计算机的叠加功能对记录进行分析。在波浪作用开始时，剖面变化很快。但当轮廓达到“稳定S形”时，它逐渐减小并最终停止。剖面变化的表达式为S=c_0+c_1EXP（-c_2n），其中c_0，c_1，c_2为常数，n为作用波数。本研究还对轮廓形状进行了建模。通过相同波高和周期的重复实验，获得了给定波高和周期条件下的期望斜率剖面。将预期的波形与瑞利波高度分布相连接，以n计算预期的波形变化。从这项研究的结果，3级的可靠性分析的可能性显示在块防波堤的稳定性的模型研究。

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.