Optimization Design For Drainage Pipe Network Using Adaptive Genetic Algorithm

With the progress of urbanization and the enlargement of city scale in China, the optimal design on rehabilitation and extension of urban drainage networks poses a key task to the water and wastewater engineers. In recent years, frequently flooding in the north and South, due to the increasing impervious surface of the city, some drainage pipes cannot eliminate the peak of storm rain water, bring inconvenience to people’s life and safety and some even endanger life. The city water supply and drainage networks related to the construction of the ecological environment and the quality of life for city dwellers, so research on optimization of drainage network is becoming more and more important.In recent years, there has been an attempt to the application of Genetic Algorithm in the calculation of drainage pipe network, but for medium and large drainage pipe network optimization is very few, and in the use of Genetic Algorithm, use the fixed crossover probability and mutation probability, and easy to fall into local optimum, because regardless of fitness big or small both adopt fixed crossover and mutation probability, cannot fully simulate the nature principle of " Natural selection assures the survival of the fittest". So in view of the above problems, this paper adopts Adaptive Genetic Algorithm, the crossover probability and mutation probability were varied according to the fitness value, use MATLAB programming. It also uses the Excel form to calculate the velocity and slope after selecting feasible diameter and full of degree, repeatedly check guarantee the diameter not eliminated because of hydraulic constraints, enrich the space of feasible solution. First, through the simulation analysis of the main pipe, the fitness adaptive probability parameters, and compared with the basic Genetic Algorithm optimization, faster converge to the optimal value and find the cost-saving design of drainage network. Then by using Adaptive Genetic Algorithm to optimize the design of medium drainage pipe network in some areas, compared to the Excel table calculation, also can find the cost-saving design of drainage network, so the Adaptive Genetic Algorithm is suitable for optimization design of drainage pipe network, and can find the cost-saving plan.