Research On The Optimization Scheme Of The Reconstruction And Expansion Of The Water Supply Network In A Small And Medium-sized City

The water distribution network is the lifeline of the entire city,and it has an important significance for ensuring the development of the city and the living standards of the people.With the sustainable development of cities,the existing water supply system cannot satisfy the increasing demand for supplying water,and the aging phenomenon of some urban pipe networks is serious,which is a great threat to water supply safety.Formulating a scientific and reasonable reconstruction and expansion plan is of great significance for saving investment in water distribution networks and ensuring the safety of water distribution networks.This paper takes City A,a small and medium-sized city in Northeast China as the research object,combined with the existing problems of the current water supply pipe network,and studies the water supply pipe network transformation plan of City A.The main research results are as follows:Based on the collection of water supply network data in the study area,this paper uses EPANET and Hongye municipal pipeline software to simulate and analyze the operating conditions of the current water supply network.At the same time,the most unfavorable point of the current network is checked.The results show that more than 60%of the node pressures in the study area cannot meet the requirements of the specification during certain periods,and the flow velocity of more than 80%of the pipe sections is below 0.6m/s,the pipe network velocity is low,and the unit head loss of some pipe sections is high.Based on the basic data of the study area,the demand for water supply network reconstruction was analyzed,and the scope of water supply network reconstruction was finally determined,including new pipelines and renovation of old water supply pipelines.In response to the transformation needs of the water supply network in City A,a minimum value of the operation and expansion cost of the pipe network,the minimum value of the residual head variance of the pipe network nodes as the objective function,and hydraulic balance,water pressure,pipe diameter,flow rate,etc.,are established as the objective function.Multi-objective optimization,modification and expansion model.After comparison and analysis,the whale optimization algorithm was selected as the algorithm for solving the optimization reconstruction and expansion model,and the algorithm was improved.On the one hand,the adaptive inertia weight was introduced to improve the local search ability of the algorithm,and on the other hand,the fast non-dominated sorting was introduced to make it possible.It is suitable for solving multi-objective optimization models,and organically combines the improved whale optimization algorithm with the optimization design model of water supply network reconstruction and expansion,laying a foundation for practical engineering solutions.The traditional reconstruction and expansion method was adopted to preliminarily determine the transformation plan of the water transmission and distribution pipeline.After comparison,the plan of using the“special water pipeline to directly supply to the iron crossing point”was finally determined.The water distribution pipeline transformation plan mainly includes pipeline network connection,in-situ transformation of old pipelines,adjustment of pipe diameters of some pipe sections,and new pipelines in the North Lake area.On this basis,the improved whale optimization algorithm was used to solve the optimization design model of water supply network reconstruction and expansion,and the pipe diameter combination scheme was determined.The comprehensive evaluation of the water supply network after reconstruction and expansion was carried out,and the economic evaluation was carried out using the value engineering method.The V value index of this reconstruction project was 0.88 RMB/m~3,which was lower than the average economic cost range of the water supply network;After the expansion,the degree of freedom of the system is 3,and the reliability of the entropy value is5.15,which are close to the theoretical maximum;the analysis results of the operating conditions show that the node pressure of the water supply network after the expansion meets the requirements 100%,and the flow velocity and the head loss per unit pipe length are also Both have been greatly improved compared with the previous renovation,which proves that the renovation and expansion plan is economical and reasonable,and can meet the requirements of the renovation and expansion project.