Research On The Key Technology Problems Of The Coastal Embankment

This thesis does research on the key technology problems of the coastal embankmentdepending on two coastal embankment projects in Zhu Hai. Now there are some technicalproblems needed to solve in design and construction of the coastal embankment. And it isdivorced from reality that specifications are referenced simply. In order to explore the ways tosolve these problems, this thesis does the following work:(1) General Extreme Value (GEV) distribution is used to analyse the tidal levels of theBai Jiao tide station including the highest tides. It is shown that good results of curve fittingmay be obtained by using GEV distribution. The different copula functions are used to buildthe bivariate joint distribution of the tidal levels of the Zhu Yin tide station and its upstreamcorresponding flood discharge and the tidal levels of the Zhu Yin tide station and itsdownstream corresponding tidal level. The results show that the different copula functions canbe used to do the quantitative analysis of floods meeting with tides.(2) The orthogonality analysis method is used to do sensitivity analysis of the factorswhich affect the wave run-up. Based on the formation mechanism of wave run-up and theresults of sensitivity analysis, not only the wave run-up on the normal direction should becalculated, but also the wave run-up of different wind directions should be calculated, whenthe waters boundary of the coastal embankment is unregular, compared with the commonmethods. This method has the theoretical basis, and the calculation results comply with theengineering actual situation. This method has engineering value.(3) Research is done to analyse the influence which is caused by different slope ratio ofriverside slope and different width and height of berm on wave run-up. Limit equilibriummethod is used to analyse the stability of different embankment structural shapes. Finiteelement method (FEM) is used to analyse the settlement of different embankment structuralshapes. Based on the analysis results, the thesis summarizes the advantages and disadvantagesof different embankment structural shapes, and puts forward how to choose the rightembankment structural shape and design the embankment structure combine with theengineering projects.(4) The mechanism of soft ground treatments are analysed which include the methods of riprapping to extrude silt, drainage consolidation method and cement-mixed piles method.The design methods including the method of riprapping stones to extrude silt and drainageconsolidation method are introduced combine with the engineering projects. Limitequilibrium method and FEM are used to analyse the effect of the above two methods. Andthe advantages and disadvantages of the above two methods are summarized. Besides, theinfluence of the change of pile’s distance and pile’s length on the stability of embankment isanalysed by using limit equilibrium method, and the influence of the change of pile’s distanceand pile’s length on the settlement of embankment is analysed by using FME. Results showthat the stability of embankment is improved and the settlement of embankment is reducedwith the decreasing of pile’s distance and increasing of pile’s length. But the trend ofimprovement of stability and reduction of settlement is reduced.(5) Based on the studies on the flow characteristics of river network at home and abroad,bank collapse is occurred easily in confluence and bifurcation area combine with the analysisof practical bank collapse in river network. Besides, ebb tide has negative effects on thestability of embankment through the studies on the influence of tidal action on bank collapse.Therefore, in order to protect the embankment where the bank collapse is occurred easily,riprap protection should be designed reasonable.The thesis does research on the key technology problems of the coastal embankment,puts forward the methods to solve these problems for reference of the design and constructionof similar engineering projects.