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原文传递 BERM BREAKWATERS: A FLEXIBLE CONSTRUCTION – AN EXCELLENT WAVE BREAKER SOME RESULTS FROM MODEL TESTS

题名：	BERM BREAKWATERS: A FLEXIBLE CONSTRUCTION – AN EXCELLENT WAVE BREAKER SOME RESULTS FROM MODEL TESTS
作者：	A. JACOBSEN; J.E. HAGEN; A. ANDERSEN; C. SOLBERG; G. VIGGOSSON; S. VOLD; S. BJQDAL
关键词：	BREAKWATERS; A FLEXIBLE CONSTRUCTION
摘要：	Breakwaters are constructed to achieve acceptable conditions for ship, effectively loading and unloading at berth. In rough sea the berm breakwaters have proven to be an advantageous construction. Compared to a conventional rubble mound breakwater a static stable berm breakwater of equal length gives significantly better wave damping, especially in the area along the breakwater. In some situations, the quarry did not contain necessary amount of blocks with sufficient weights for a static stable construction. An alternative could then be to construct a berm breakwater of the type static stable after reshaping. This paper describes a comprehensive model test where the wave damping effects for reshaped and non reshaped breakwater heads are compared. The model test also includes the effects of different size of the porous volume in the berm. The wave overtopping and through-flow are also measures for different degree of reshaping. Longshore transport during reshaping under attack of breaking oblique waves is important in design of a reshaping berm breakwater and some results are presented. Wave reflection is an important factor for the wave climate in the approach area. The wave measurements outside and around the breakwater head are analysed in the frame of dangerous waves. From the tests it could be concluded that reshaping of the berm in a natural way improve the wave damping for ocean waves and swell. For shorter waves the reshaping will increase the wave disturbance behind the breakwater. The wave propagation around a berm breakwater are just slightly dependent on the proportion of the porous volume, provided that the porous layer has a minimum thickness. The form and the dimensions of the berm breakwater in relation to the wave length are a more important factor. The wave overtopping and through-flow of the upper part of the breakwater increase with increasing reshaping. It should be noted that single waves and certain combinations of waves can create overtopping and through-flow of a large volume of water in a few seconds. Breaking oblique waves create a stronger longshore transport than could be calculated from the common-used formula based on non-breaking waves. Especially, great discrepancies from the theory could arise due to concentration of wave energy from strong refraction effects along the breakwater.
总页数：	Proceedings of the 30th PIANC-AIPCN Congress. Sydney Australia. 22-26 Sept. 2002. pp18
报告类型：	科技报告