西非某深水斜坡式防波堤设计要点分析

Analysis on design points of a deepwater mound breakwater in West Africa

为了优化复杂地质条件下强涌浪海域的斜坡式防波堤设计,确保工程质量与施工安全,提出了西非某深水斜坡式防波堤工程的初步设计方案,并进行了物模试验验证。在现场勘查的基础上,研究了不同水位和波浪组合情况下断面的护面块体、护脚、胸墙、低堤顶的混凝土路面的稳定性,测量了越浪量以及堤后波高,对腐木段地质处理以及防波堤分期建设等提出了针对性的施工建议。结果表明,1)5 t与8 t中国扭王块在西非10~16 s涌浪环境下是适用的;2)涌浪对于护面块体的稳定有明显的影响,近岸段需增加压脚块石,以确保护面块体的局部稳定;3)越浪量标准可分级为运营工况(q≤0.5 L/(s·m))和校核工况(q≤20 L/(s·m));4)腐木地质强度随着木质结构的腐烂程度而逐渐减弱,可使用开山砂和风化岩作为换填料来处理;5)对于低堤顶的混凝土路面的设计,要优先考虑越浪对结构稳定性的影响,同时在运营期间限定人员车辆可作业的波高。研究成果较好地解决了复杂地质条件下防波堤易出现的稳定性及沉降等问题,对类似海岸涌浪环境下的工程建设具有参考价值。

In order to optimize the design of rubble mound breakwaters in sea areas with surging wave under complicated geological conditions and to ensure the engineering quality and construction safety,a tentative design proposal for a deepwater mound breakwater project in West Africa was presented,and the physical model test was made to verify the proposal.On the basis of site investigation,the stability of armor block of the cross section,toe,crown wall and concrete pavement at the low embankment top were studied under different combinations of water levels and wave heights.Meanwhile,the wave overtopping and wave height behind breakwater were measured and some suggestions regarding the geological structure of rotten wood and phased construction were put forward accordingly.The results show that:1)5 t and 8 t accropode blocks are used in swells of 10~16 s in West Africa successfully.2)Swells have a significant effect on the stability of the armor block,so the toe rock is added to ensure the local stability in the nearshore section.3)The standard of overtopping criteria can be divided into operation condition(q≤0.5 L/(s·m))and check condition(q≤20 L/(s·m)).4)The geological strength of rotten wood gradually weakens with the decay of the wooden structure,which should be filled with sand rock and mantle rock.5)For the design of concrete pavement at the low embankment top,it is necessary to give priority to the influence of overtopping on the structural stability,and to limit working wave height for personnel and vehicles during the operation.The results have solved the issues of stability and settlement of breakwaters easily occurred in complicated geological conditions,which can be used as a reference for the construction under similar surging wave circumstances.