Experimental Study On Water And Sediment Characteristics Of Shipping Junction In Curved Channel

Since ancient times,inland river shipping has been playing an irreplaceable role in transportation because of its advantages of large cargo carrying capacity and convenience.With the development of economy and society,China's demand for inland river shipping is increasing day by day.In order to develop the inland river shipping potential,China has put forward the National Inland Waterway and Port Layout Plan(2006 ? 2020)to transform the rivers with shipping potential to meet the increasing requirements of inland river shipping.In order to meet the national requirements for shipping,most rivers need to be upgraded,and most inland rivers in China are winding,so it is of great significance to study the characteristics of water and sediment at shipping junctions of curved rivers.In this paper,based on the fifth-class shipping hub(Gutan section)in Nanyang,aiming at the complex water and sediment characteristics of the shipping hub when it is located in the curved reach,the overall hydraulic model of Gutan shipping hub is established.The influence of different operation modes of control sluice,length optimization of diversion dike and different opening modes of diversion dike on navigable flow conditions and scour and silt changes of the upstream approach channel and its entrance area of the hub is studied to provide reference and suggestions for practical engineering operation.The specific research results are as follows;(1)The influence of different scheduling modes on navigable flow conditions of the hub is obtained by conducting clear water and muddy water tests on different scheduling modes of the control sluice;When the upstream inlet flow is less than 2000 and the control lock does not need to be fully opened to regulate the inlet flow,the control lock at the far end of the lock can effectively reduce the oblique flow,cross flow and large range and high intensity backflow in the approach channel of the junction,which can greatly improve the navigable flow conditions of the junction.At the same time,the operation mode of opening the far end of the lock can reduce the backflow siltation caused by the upstream gate area of the hub and the density current siltation in the approach channel to a certain extent.(2)Through the length of the diversion dam,according to a study for the bending river hub,appropriate change diversion dike length,adjust the pier head position,make to the top of head of diversion dike and river bend Angle of attack of attachment and river flow direction in the mainstream or minimize its Angle,at the same time the diversion dam does not affect the river mainstream,upstream hub as well as the approaches and the area at the entrance of the reflux flow further weakened,to improve the navigation flow condition and reduce the fall silting of all have very good effect.(3)Tests of clear water and muddy water containing sand were carried out for different opening ways of diversion embankment respectively,and the tests showed that;After the diversion dike is opened,the backflow at the upstream gate of the hub basically disappears under the condition of small flow.When the upstream inflow flow is large,there is still a small-range and low-intensity backflow area,whose strength has no impact on the navigation safety of the hub by test measurement.At the same time,due to the weakening of reflux,the reflux deposition of sediment in the mouth area has been greatly weakened,the test shows that the way of opening holes at the bottom of the diversion embankment has the best effect on improving the water and sediment condition of the junction.