Optimization Of Typical Rural Water Supply Network In Mountainous City Based On The NSGA-Ⅱ Algorithm

As an essential infrastructure,water supply system plays an extremely important role in ensuring people’s livelihood and urban economic development.As the main part of water supply system,water supply network plays a very important role in the process of water delivery.The water supply pipe network system of typical villages and towns in mountainous cities has the following characteristics: first,the terrain fluctuates greatly,the height difference is great,the pipe network layout is complex,and most of them are tree-shaped pipe networks,resulting in the uneven distribution of pipe network pressure and the pipe explosion problem.Secondly,due to the limitations of geographical and environmental factors,mountain pipe network is difficult to form a ring and has low reliability,which is prone to water outage and small amount of water,which cannot meet the water demand.Therefore,according to the characteristics of typical villages and towns in mountainous cities,an optimization model of water supply network which can work out the economic pipe diameter can effectively control the construction cost and pressure.The paper studies the influence of the selection of pipe material and pressure value on the cost of pipe network in mountainous villages and towns,by collecting the location of the project pipeline price information in Matlab software for different material,different pressure value of the pipelines for curve fitting,it is concluded that the PE100 feed pipe 0.6 MPa,0.8 MPa,1.0 MPa,1.25 MPa,1.6 MPa and steel skeleton clad pipe 1.0 MPa,1.6 MPa,2.0 MPa,2.5 MPa pipe cost formula.The characteristics of different zoning methods and their application in water supply network layout in mountainous villages and towns are summarized through literature review.The optimization model of water supply network is established based on the characteristics of mountainous villages and towns.The economic objective function includes the construction cost of pipe network,pump station and pool and the power cost of pump station.The reliability objective function is determined by calculating the average surplus water head of nodes.This model is a multi-objective optimization model with pipe diameter as independent variable.At the same time,considering the construction cost and water pressure distribution of the pipe network system,it has practical significance to reduce investment and improve operation status in the optimization process of water supply network in mountainous villages and towns.Take rensha town of Fengdu County of Chongqing as an example to study the water supply network.The elevation difference of the water supply pipe network in Rensha Town is significant,and the distribution of the pipe network is in the form of tree network,mainly using gravity water supply,with the characteristics of typical villages and towns in mountainous cities.In Matlab software using the NSGA-Ⅱalgorithm for this optimization model,a pipe network in conversion cost is210306.37 yuan,compared with before optimization reducing 83589.83 yuan,and node average surplus waterhead reduce 5.84 m,total years reduced costs by 14.19%.At this time,the corresponding pipe diameter combination is 160 mm,110mm,90 mm,110mm,63 mm,110mm,32 mm,32mm,110 mm,90mm,40 mm,63mm,50 mm.The results show that the pipe diameter combination obtained by the optimization model can significantly reduce the construction cost of the pipe network and improve the reliability of the pipe network system.