Study On The Characteristics Of Traffic Flow And The Scheme Of Dredging In Fujiangsha Waterway

The Fujiangsha waterway is located in tidal reach,with narrow and curved channel and complicated navigation environment.The waterway is the key maintenance area of the 12.5-meter deep water channel in nanjing of the Yangtze river.Dredging is carried out directly on the main channel with dense traffic flow,which increases the contradiction of navigation.The characteristics of vessel traffic flow in fujiangsha waterway are studied and the scheme of vessel safety avoidance during dredging is put forward to ensure navigation safety.The present situation of dredging construction area of Fujiangsha waterway was investigated,and the characteristics of vessel flow of each waterway were discussed based on the continuous 24 h on-site observation of traffic flow of Fujiangsha waterway.The AIS data in the waterway were mined,and the AIS was checked and corrected with field observation data.Based on the on-site measured and revised AIS data and the tidal level data of Tiansheng Port,the spatiotemporal characteristics of traffic flow in Fujiangsha Channel were analyzed.The characteristics of time variation of traffic flow are as follows: hourly traffic flow is related to the change of tide level;The daily total number of ships is not affected by the tidal level and the quantity changes stably.The ship traffic flow within a month is affected by spring and neap tides.The relationship between the number of hourly traffic flow and the tide level is more obvious during spring tide.The characteristics of ship flow variation in the year are that the total flow of each section changes smoothly in the flood,middle and dry season,and is less affected by the average monthly tide level.The spatial distribution characteristics of traffic flow are as follows: the spatial distribution characteristics of traffic are consistent with channel conditions and route rules,and the upstream navigable diversion is selected when the ship is up,while the downstream navigable diversion is selected when the ship is down.According to the maintenance dredging construction ship type and construction scheme,the navigable ship type of each waterway during the construction period was calculated: ships with navigable length below 150 m for Fubei waterway and all types of ships for other waterways.Two kinds of ship avoidance schemes are put forward: first,based on the characteristics of navigable vessels,a diversion scheme is proposed to divert the transit vessels over 110 meters in length from Fubei waterway to Liuhaisha waterway.Second,a scheme of avoidance is put forward based on the daily variation law of traffic flow.According to the present dredging tasks and the characteristics of traffic flow vessels,construction is selected to avoid the peak period of traffic flow for construction,and the ships are allowed to avoid according to the regulations.