Analysis And Prediction Of Siltation In The Dredging Channel Of Large Bay

The port construction of China has been developed over a period of time, Zhejiang coastal ports group has been formed into the basic pattern of which Ningbo-Zhoushan port as the core, Wenzhou and Taizhou ports for the two wings. But deep shoreline district distributed extremely disequilibrium, Wenzhou and Taizhou was lack of deep water berth. If the large bay built deep water berth by the means of dredging engineering, realizing "use shallow water as deep one", it will bring the back silting problem of dredging channel. Therefore, the key point of realizing "use shallow water as deep one" in a large bay is how to analysis and predict siltation of dredging channel scientific.This paper taked Yueqing Bay hydrologic measured data as basis, using two-dimensional hydrodynamic model for numerical simulation of the port and its adjacent waters before and after the dredging engineering. Analyses of6subregion in dredging channel waters have been made:two areas upper and lower dredging channel had the scouring and siltation status alternately monthly, erosion is significantly greater than the siltation amount, scour depth of0.35m and0.25m; the right area silted continuously, total siltation amount is0.3m; the left area also had the scouring and siltation status alternately monthly, the total siltation amount is0.2m; the siltation amount of two districts in the dredging channel by month is less than0.25m, the total thickness is0.8m.Siltation of Yueqing Bay dredging channel has been predicted by two methods: time series analysis(TSA) and grey theory, which didn’t take volatility uncertainty into consideration. According to dredge channel siltation in sequence has a fluctuation growth characteristics, this paper puts forward the timing analysis-Markov chain prediction mode(TSA-Markov chain), which can not only meet the trend prediction, but also considerate of volatility uncertainty. The hindcasting of Yueqing dredging channel siltation shows that the forecasting accuracy of TSA-Markov chain model, comparing with that of TSA and grey theory, is significantly improved. The dredging channel siltation of Yueqing bay has been forecasted by TSA-Markov chain model:10months later, scour depth of upper and lower areas are1.57m and0.58m; siltation amount of left and right areas are0.38m and0.67m; siltation amount of main area is0.97m. It can provide a theoretical basis for the Yueqing Bay waterway remediation work, and the research foundation of the development of port construction in large Bay.