Study On The Improvement Potential And Passing Capacity Evaluation Of The Channels In The Upper Reaches Of The Yangtze River

As an important part of the Yangtze River’s main route,the issue of rational planning of the upper Yangtze River channel scale has been the focus of extensive attention and difficulties.Under natural endowment conditions,the upstream channel’s upgrade potential,channel passage capacity,and channel scale and economic development are the fundamental problems in the channel’s planning decisions,as well as important pathways to assess whether the channel’s transport carrier function can be performed.The systematic study of these elements is an important guide for the selection of upstream channel classes and the determination of passage capacity.At present,there is no systematic and complete research on the upgrading potential of the upper Yangtze River channel in terms of the upstream channel’s upgrade potential,channel passage capacity,and channel scale and economic development under natural endowment conditions.In view of this,this paper is based on basic information on shipping in the Three Gorges Dam to Yibin River section of the upper Yangtze River and socio-economic information in the hinterland.The main work and conclusions are as follows.(1)Based on the verification data of the upper Yangtze River channel,937 sections of excellent river section were selected,and the "stable depth estimation method" was used to estimate the exploitable scale of the Fuling to Yibin river channel.The preliminary projection is that the section from Chongqing to Yibin can meet the secondary standard of the inland waterway,Fuling to Chongqing can meet the first level standard of the inland waterway.From the principle of stable bathymetry estimation method,the calculation process of river phase relationship coefficient and water depth correction coefficient is simplified and improved,and the stable bathymetry estimation method under multi-stage flow is proposed.The conclusion is that the consistency of the computational conclusions obtained through validation can be used initially to guide relevant calculations of the channel-scale potential.(2)Based on the method for calculating the passage capacity of inland waterways of ship traffic flow,the theoretical annual passage capacity and design annual passage capacity of two-way waterways in the upper reaches of the Yangtze River were calculated.Combining with the control section vessel scheduling rules,a priority M/M/1 queuing service model was established by analyzing the traffic flow of vessels in typical cross-section of Yangtze River and the queuing time distribution of vessels in the control river section.The queuing loss time of each control river section was quantitatively estimated,and then the passage capacity of each single-line control river section was calculated.(3)The process of transporting goods in the shipping lanes has been generalized into three more concise processes,and the level of shipping demand carried for waterway capacity is evaluated by establishing the shipping demand indicator(WCI)which based on the principle of supply-demand balance.According to the input-output theory,a forecast of shipping demand for each segment of the upper Yangtze River was made.Combining with the passage capacity of the channel,then the WCI was obtained.The results show that: from 2020 to 2040,the dam to Fuling section is in surplus,the bearing level of the Fengdu to Fuling section is low,and he WCI is reduced from 1.82 to1.36;the Fuling to Chongqing section is in deficit after 2030,and the WCI is lower than the equilibrium critical value1,meaning that it should be considered to improve the passage capacity of the obstructed river section;the overall bearing level of the Chongqing to Yibin section is not high,and the average WCI is reduced from 1.71 to1.26.Considering the trend of ship enlargement,it is suggested to improve the regional waterway conditions through engineering means to meet the development needs of ship enlargement.