Investigation,Evaluation And Research Of Drainage Pipe Network In A District Of Zhenjiang City

As an important part of urban drainage facilities,drainage pipe network has the characteristics of foundation,openness and complexity.Since the relevant state departments proposed to implement the action of improving the quality and efficiency of sewage treatment facilities in 2019,a large number of researches have focused on improving the treatment efficiency of sewage treatment plants.Therefore,the investigation and evaluation of the drainage pipe network in the built-up area of Zhenjiang City aims to grasp the health status of the drainage pipe network in the area,and analyze the problems of external water intrusion and high water level operation in the dry season in the drainage pipe network.This can help the treatment plant achieve the purpose of improving the quality and efficiency of sewage collection and treatment.In the early stage of this study,through on-site investigation,data analysis and mapping,the current situation of the drainage pipe network system in the built-up area A and the sewage treatment plants and lifting pumping stations serving the area was understood.The results show that the centralized collection rate of urban domestic sewage in Area A is 72.1%,and the stability of sewage treatment facilities in the area is easily affected by rainfall.Based on the current situation,a water quality monitoring method for the drainage network with water quality characteristic factors as the core was established.Furthermore,combined with the water quantity data,a quantitative analytical basic equation for the proportion of each mixed source in the sewage system based on the chemical mass balance model was established.The analysis results show that the main types of external water intruded into the sewage pipe network on sunny days are groundwater and river water.Groundwater and river water intrusion account for 32.24% and 6.18% of the total sewage pipe network transportation,respectively.Based on the analysis results of water quality and quantity,the inspection and investigation of key areas of extraneous water intrusion were carried out,and it was found that there were 1246 structural defects and 616 functional defects in the pipeline network,which affected the water delivery efficiency.Based on the data obtained from the pipe network investigation,an evaluation index system for the health status of the drainage pipe network was constructed,and the scoring method was determined according to the characteristics of individual indicators.The combined weighting method is used to determine the index weights of the index layer and the criterion layer,and an evaluation model of the health status of the drainage network is established based on the fuzzy comprehensive evaluation theory.The evaluation results of the health status of the drainage network are divided into five grades: sickness,moderately pathological,general pathological,sub-health,and health.The semi-trapezoidal function is used to determine the membership degree of each index evaluation level,and the final evaluation level is determined according to the weighted average method,the fuzzy distribution method,and the confidence criterion method.According to the results of the assessment model of the health status of the drainage pipe network,the overall health status of the sewage pipe network in Area A is generally pathological,of which the healthy and sub-healthy state account for 52.98%,and sickness and moderately pathological account for24.43%.It needs to be rectified and repaired in time.This paper has a strong guiding role in the investigation and evaluation of the drainage pipe network by innovating the investigation method of the drainage pipe network and establishing the health status assessment model.