Research on structural types and transmission coefficients of submerged dykes;

The submerged dyke plays an important role in protecting bank and promoting beach accretion,and the project benefit and economic input of submerged dyke are af- fected by its structural form and height.

The flow of a non-gap submerged dyke system is unsteady,the sluice and water level of the dams area have a close relation to the effect of beach protection and siltation promotion of the submerged dyke and the structural stability of dams.

Base on the analysis of a real example of determination of dike top construction allowance for settlement for heightening a submerged dike on soft soil,this paper studied and discussed the method for determining the construction elevation in heightening of submerged dike.

However, because there are many types of the submerged dike, it is hard to get a unifying result, in the real projects and in most cases; they will have to depend on the results of physical model experiment.

Based on the Boussinesq type equations with the second order nonlinearity and dispersion,an improved Crank-Nicolson method is employed to simulate the evolved wave propagation passing over the submerged bar.

The ivestigation of applicability of the numerical model,numerical simulations were done upon the relatively steeper submerged bar.

To investigate the applicability of the numerical model, further numerical simulations of wave propagating over a submerged bar are done.