Study On Through Capacity Of Port Collecting And Distributing Road Based On Reliability Theory

In recent years, with the rapid growth of the seaports’ cargo throughput, more and more deep-water berths and channels are under construction in our country, which greatly improves the through capacity of seaport. As an important part of the collecting and distributing system on land, the capacity of the port collecting and distributing roads has become a restraining factor to the development of seaports. Assessing the through capacity is an important issue for planning and designing collecting and distributing roads, a reasonable method to calculate and evaluate the through capacity based on the traffic features of port collecting and distributing roads is the key to solve the allocation problem of through capacity.The existing researches on port collecting and distributing roads’capacity are not that much, most of which are revising formulas used in general road traffic. This paper combines the concepts of through capacity of berth and channel, taking the cargo throughput as a measurement of port collecting and distributing roads’capacity. Meanwhile, the reliability theory is introduced to evaluate the operation status of the collecting and distributing traffic. This method provides a new idea for studying the capacity of port collecting and distributing roads.This study combines features of port production and operation process, summarizing the basic characteristics of port collecting and distributing road traffic by researching the traffic composition and the freight generation mechanism. After carrying out a specific analysis of traffic volume, capacity and travel time based on survey data, a new way of expressing those parameters is proposed, which reflects the features of port collecting and distributing road traffic Combining the capacity reliability and travel time reliability theory, a reliability index which is applicable to port collecting and distributing roads is proposed. The through capacity of port collecting and distributing roads is defined by taking cargo throughput as a measurement of capacity and reliability index as the evaluation standard of traffic operation status, the calculation method is then discussed. At last, this paper gives an example to calculate the reliability index and through capacity of the roads, analyzes the changing reliability index when the traffic volume was increasing, and fits a through capacity formula which is applicable to the port collecting and distributing roads in this example and other similar roads. Through above calculation, the feasibility of the reliability index and the method for measuring the through capacity of port collecting and distributing roads are examined. The results of this study can provide a reference for evaluation and calculation of port collecting and distributing roads in port planning and design.