Abstract
The problem of traffic disturbances due to wind waves has become obvious on the lakeside road of Lake Shikotsu and urgent measures are required. This study estimated the wind in the lake through the mass-consistent model taking into consideration the impact of the terrain and used Wilson's method to obtain the probability wave to be used for the design. In the hydraulic model test, we reproduced the 1/2 scale slope of the lake bottom and obtained the height of waves passing over the present embankment to compare it with the results of field observation. Then we showed that the height of waves passing over the embankment could be reduced by 50 percent if wave-dissipating concrete blocks were installed in front of the embankment. In the case of high waves equivalent to the design wave, the transition of the foot of the slope toward the offshore side of the wave-dissipating concrete blocks is apparent. Thus, we discovered offshore flows unique to the steep slope condition and the characteristics of wave power applied to foot protection blocks through the analysis using a numerical wave channel. In addition, through results of a stability experiment, we showed that flat blocks (7-ton type) were necessary as foot protection to secure stability of wave-dissipating works. Subject to implementation of such enhancement of shore protection, we made proposals for non-structural measures to ensure safety of passing vehicles.
