Study On The Navigable Water Flow Conditions And Improvement Measures In The Pilot Channel And Entrance Area Of The Cruise Ship Lock Under Continuous Sharp Bends

The Rongjiang River belongs to the Xijiang River system in the Pearl River Basin and is the middle reaches of the main stream of the Liujiang River,a first-class tributary of the Xijiang River.Rongjiang has a long history of navigation and has played an important role in material transportation and social and economic development on both sides of the river.In recent years,with the continuous strengthening of regional economic cooperation,it is required to give full play to the role of inland shipping hub and the advantages of water transportation,and Liujiang,as a northwest water transport route to the sea,plays an important role in promoting the leapfrog development of Liuzhou and Guangxi.It is planned to comprehensively improve the level and passing capacity of the Liujiang waterway.Among them,the Tai Po Junction Extension Lock Renovation Project is also included in this plan.The hub is located downstream of the continuous sharp bend section,and the upstream pilot channel of the lock is located on the convex bank of the curved river section,and the door area and connecting section of the upper pilot channel are also affected by the provoking effect of a convex mouth,and the navigable water flow conditions are very complicated.Based on the Tai Po Hub Reconstruction and Expansion Lock Project,this thesis uses the method of comparative analysis of mathematical model and physical model to explore and analyze the layout type of the barrier wall in the gate area of the upstream pilot channel and the influence of local bank slope excavation on the navigable water flow conditions of the entrance area,and draw effective improvement measures.The main research contents are:(1)Aiming at the problem of poor navigable water flow conditions in the gate area of the lock pilot channel entrance in the curved river section,the method of combining physical model and mathematical model is used to find out the main factors affecting navigation safety,and summarize the corresponding improvement measures that can be actually implemented.(2)Through the overall hydraulic physical model test of Tai Po Hub,it is found that the flow pattern in the gate area of the upstream pilot channel entrance of the design scheme is poor,which affects the safe navigation of ships,therefore,in view of the problem that the upstream pilot channel has too long a barrier wall,an optimization scheme to shorten the length of the barrier wall is proposed.Through the comparison of the results of the two schemes,it is concluded that the optimization scheme effectively reduces the longitudinal and transverse flow speeds in the entrance gate area,can better meet the requirements of the safe navigable water flow conditions of the ship,and considers the comprehensive engineering investment and other aspects,and the optimization scheme is considered feasible.(3)Two-dimensional numerical simulation of the curved river section upstream of the Tai Po Junction dam site,from the establishment and verification of the model to the analysis of numerical simulation results,and the mutual verification of the material module and digital model results.Through the comparative analysis of the results,it is found that the optimization scheme shortens the length of the partition wall of the widening section of the pilot channel,so that the proportion of the overflow section area in the pilot channel entrance gate area to the river channel overflow section decreases,reduces the occurrence intensity of longitudinal and cross-current,and effectively solves the problem of excessive longitudinal and cross-flow velocity in the entrance gate area of the design scheme.(4)According to the influence of the presence of the bulge on the navigable water flow conditions in the gate area of the pilot channel entrance area of the upstream curved river section,the control variable method was used to study and analyze the optimal arrangement length of the barrier wall under the premise of the incision nozzle by using the control variable method and combining the flow velocity results simulated by the mathematical model;The cutting nozzle scheme and the optimization scheme were compared and analyzed,and it was found that due to the excision of the convex nozzle,the provoking effect of the upstream incoming flow at the curved river section was weakened,resulting in the water flowing into the gate area of the pilot channel on the left bank being mostly along the bank,so the flow pattern became more stable and there was no backflow.