Profile Optimization Based On Improved Genetic Algorithm Railway

During railway design process, profile alignment is a very important item, because it will directly affect the investment of construction and operation of a line.Therefore, conducting the study of profile optimization can bring practical social and economic benefits.With further study, researchers at home and abroad have proposed many profile optimization model and algorithm to better meet the needs of practical engineering.Through analysis and comparison of various kinds of methods, the optimization model based on the satisfactory degree theory has been established. And improved genetic algorithm has been designed to solve the model.Mainly works of this paper are as following:(1)In order to correctly lead slope trend, preliminary feasible region which is determined by maximum limiting gradient have been used to modify profile ground line which is ups and downs.Then, ground line which was modified has been smoothed to determine the number of slope changing points automatically. The profile plan has been created by integrating uniform distribution method, fitting method and normal distribution method. Base on the hypothesis that the plan meet the demands of constraint condition and population diversity, initial population of the improved genetic algorithm have been formed.(2) Using the slope changing points, mileage and design elevation as variable of optimization design, satisfactory degree theory has been induced to establish profile optimization model,which can comprehensively consider both construction and operation. Base on analysis of connotation of profile design, multi-objective fitness functions have been established. Single slope fitness function has been proposed to draw into crossover operator, in order to moving direction of the slope changing points.Variation range of mutation operator and virtues or defect degree of the plan have been related to accelerate searching speed of the algorithm.(3)On the basis of profile optimization theory, using VC.NET and ObjectARX2006,profile optimization program integrated with the satisfactory degree theory and the improved genetic algorithm has been drawn up.Parallel relation of the optimization algorithm has been disposed with multithread technology which can reduce time of the profile optimization effectively.(4) Using the program to do optimization analysis for engineering examples under different conditions, the effectiveness and practicability of the program have been checked.