THE STUDY ON APPLICATIONS THE CONSTRUCTION METHOD OF OVERFLOW IN THE DREDGING ENGINEERING OF THE YANGTZE ESTUARY

摘要

The construction method allowing an overflow during loading is commonly applied to self-propelled trailing suction hopper dredgers, which can discharge the silty fluid of low density in the upper layer of hopper so as to leave more tank volume to load the silty fluid of high density,to improve actual work per ship load and raise the efficiency of the ship. The effect of any overflow during loading in the Dredging Engineering of the Yangtze Estuary is difficult to answer due to the fact that the length of channel is more than 92km and there is a great difference in the soil and flow conditions. The properties and method of overflow from the ship is also not the same. In order to know the diffusing range and the motion law of the different methods of overflow in different regions of the channel, construction data analysis, 3D numerical model simulation and ADCP measurement have been carried out since September 2007. The results shows that the diffusing range and length of the sediment from overflow ports is limited because of the characteristics of the soil and flow in the Yangtze Estuary. It is difficult to realize the aim of transporting the dredging sediment through overflow out of the North Passage of the Yangtze Estuary and reducing the amount of siltation .