| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
In order to investigate the standard value on the wave-making signal length of random wave in the experiments of stability weight of armor units on breakwater, firstly, the wave-making system which faithfully reproduces the simulation wave is developed, secondly, the influence of wave-making signal length on damage of armor units and the damage mechanism of units are investigated by the experiments and numerical simulations. Finally, by focusing the relationship between damage of units and the history effect of the wave actions, the wave group characteristics in the damages are assessed stochastically. Main conclusions are as follows:
(1) In the result of examining the probability of the wave height over limitative wave height which brought about the damage of armor unit, it is proven that the probability is largely affected by the number of the wave which composes the random wave. It can be confirmed from the dynamic simulation that the damage mechanism of unit is the memory type, in which the wave action hysteresis is related.
(2) The probability characteristic of both surf similarity parameter E at the damage and just prior to damage approximately came in the Weibul-distribution, the most of E is concentrated in 2<__=ξ<__=3.5.
(3) The appearance characteristic of wave group in the dangerous condition for units was analyzed for simulation waves of the 10,000 cases every 7 kinds of wave-making signal length. As the number of waves in wave-making signal is less, the standard deviation of the appearance frequency increases.
(4) About 600 waves which both standard deviation of the appearance frequency of the wave group and the damage rate of units in the damage experiments become small and almost constant, are proposed as minimum standard on the composition wave number of random wave in the stable experiments of the units.
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