In consideration of studying island coast hydrodynamic factors is in order to build breakwater engineering , design waves , astronomic - tide and storm - tide which increases water level are computed to offer design parameters , discuss and analyze the influence of engineering safety aroused by those factors 考虑到研究海岛周围海岸动力因素的目的是为了建设海岛工程，还进行了设计波浪以及天文潮、风暴潮增水的计算，分析了这些因素对工程安全性的影响。
The fundamental ideas and methods of this paper are also illuminated in this chapter . in chapter two , a one - dimensional and semi - closed shallow sea mode is studied . the approximate analytical expressions of the water level at the top of the bay induced by the nonlinear interaction between the storm surges and the astronomical tides are obtained by using the perturbation method 在第二章里，研究了一维半封闭水域中的非定常风暴潮与天文潮非线性相互作用的问题，用摄动方法求出了具有实际意义的海湾顶部增水水位的一阶近似解析表达式，并给出了增水过程曲线。
The local current disturbance after bridge being built in qiantang estuary leads to correspond changes of riverbed near bridge . but there is not any impact on astronomical tide , runoff large - scaled river shape and riverbed after bridge being built . so it does n ' t change the formation of tidal bore at all after bridge being built , but there is some impact on the shape and intensity of tidal bore because of pier resistance 在钱塘江河口建桥将引起局部水流的扰动及近区河床的相应变化，但不会对天文潮、径流及大范围河势、河床产生影响，因而，建桥不会从根本上改变涌潮的产生，但桥墩阻力对涌潮形态和强度是有影响的。
It is found : ( 1 ) when the current direction is close to that of the line through the two caissons ' centers , the current speed within the area between the double caissons apparently decreases ; ( 2 ) sea ice ride - up and pile - up against the outer side of the caissons are similar to that against single caisson , and sea ice ride - up and pile - up are determnined by the sea ice velocity , sea ice thickness , tide and the storm set up ; ( 3 ) when locate two caissons , the tops of the two caissons in the shield area are no ice covered 研究发现： ( 1 )当海流流向与双沉箱的中心连线相近时，双沉箱对峙区的流速明显减小； ( 2 )双沉箱外侧区域的海冰爬升和堆积与单沉箱时基本相同，其爬升和堆积与海冰的速度和厚度、天文潮高等有关； ( 3 )双沉箱设置时，对海冰爬升和堆积会起到有效的屏蔽作用，对峙区内的双沉箱顶上不再有海冰堆积。
