沉箱式防波堤蛇行破坏的期望滑移量模型

Expected Sliding Distance Model of Meandering Damage to the Caisson Breakwater

防波堤是港工建筑物中的一个重要组成部分,主要作用为保护港湾免受波浪、冰、沙等海洋动力因素的侵袭。综合以往的相关文献,对于防波堤断面破坏形式,如滑移、倾覆、地基滑动等有了非常充分的研究,可以定量计算出其损坏程度。而对于防波堤平面形态的损坏,如蛇行破坏等,只是较深入研究了失效机理,并没有一个能够定量计算其后果的模型。本文第一部分将期望滑移量模型和绕射模型结合,建立了计算半无限长沉箱式防波堤在使用期限内蛇行破坏程度的模型。第二部分则利用实测的波浪数据设计并计算了一个沉箱式防波堤实例。结果表明,各个堤段的期望滑移量呈现出一定周期性变化的规律,堤头附近区域的滑移量远大于较远的堤段,这对于防波堤施工过程中的堤头防护具有参考价值。本文为建立防波堤平面形态损坏定量计算模型提供了一种思路。

Breakwater is one of important port structures, which is used to protect the harbor from being attacked by oceanic hydrodynamic forces, such as waves, ices and sand. In the past years, many literatures have studied the mechanics and quantitative models for cross-sectional failures of breakwater, such as sliding, overturning and foundation deformation. However, up to the present time, only the mechanics of the horizontal failure modes of breakwater, e.g. meandering damage, is discussed in some literatures and no quantitative models have been proposed. In the first section, this paper establishes the model of computing the consequence of meandering damage of semi-infinite caisson breakwater by combining the expected sliding distance technique and the diffraction model. In the second section, a caisson breakwater is designed and calculated on the basis of measured wave data. The results show that the expected sliding distance undulates periodically along the trunk of breakwater, which results in the meandering damage. The sliding values in the adjacent region of the tip of breakwater are larger remarkably than those away from it, which indicates the importance of protecting the tip of breakwater during the construction. This paper puts forward an idea for establishing the quantitative models for horizontal failures of breakwater.