Study On Optimal Selection Of High-speed Railway Line From Xi'an To Chengdu In Daba Mountains

High-speed rail as a new transport mode in the modern society, has a very distinct advantage. Rail alignment design is the most important and one of the key design work of the railway construction project, and it is directly related to the product quality and cost of the project The selection of appropriate optimization algorithm for optimal design becomes a very important part of the rail lines alignment design.Traditional optimization methods require a higher performance of the function, which causes a certain extent effect on the accuracy of the results,and in some cases leads to discrepancy between theory and practice.Therefore, to achieve the purpose of optimal design, a further research for more suitable algorithm is required.From the perspective of geologic factors, the analysis and evaluation on geological factors which affect the rail lines is made by the same accuracy. For choosing the best route, AHP (analytic hierarchy process) is used to determine the weights of the various influencing factors, and SPA (set pair analysis) is used in variable fuzzy sets calculation. It gains the following results:First, the principles and steps of the AHP and SPA are described and analyzed, in order to provide theoretical support for the rail lines alignment design.Second, by taking the six schemes in Daba Mountains of the High-speed rail program which are from Xi'an to Chengdu for the research objects, through the study data collection of the engineering geological conditions, field investigation, the indoor data analysis, six evaluation factors which have the impact on the program of the study area come up.Then, through a nine-scale method, it obtains the matrix of the evaluation factors on the rail program.It is calculated by AHP, to obtain the weights of evaluation factorsFinally, SPA is used for the pros and cons evaluation of each line, to choose the best alignment of optimal design.