AHP-TOPSIS Based Assessment Method For Selection Of Urban Drainage Pipe Material

In recent years,China’s water pollution prevention and control process has continued to deepen,and the scale of urban drainage pipeline systems has been increasing.However,due to improper selection of drainage pipe materials and poor construction quality,the effect of the drainage system on water pollution control and water environment quality improvement has not been fully utilized.Since 2019,China has strengthened its emphasis on the quality of drainage pipe and canal systems,and has taken the improvement of the drainage pipe system as one of the keys to improving the quality and efficiency of sewage treatment.There are many types of buried drainage pipes,and the performance,price,and application scenarios of different pipes are different.The quality of commercially available pipes varies.At present,its selection often depends on the subjective experience of design and management personnel and mainly consider the technology during construction.And economic factors.In fact,the fault tolerance of different pipes to the construction level,the probability of damage and repair costs,the environmental impact and remediation costs caused by the damage,and the life cycle environmental impact of the pipe itself will also vary greatly.Therefore,the selection of drainage pipe materials should not only consider the direct cost and technical characteristics of the construction stage,but also the cost,benefit and environmental impact of the entire life cycle.This research aims to construct a systematic and comprehensive evaluation method for the selection of municipal drainage pipes,so as to provide decision-making support for designers and managers.On the basis of consulting relevant domestic and foreign documents,this study analyzed the factors affecting the selection of drainage pipe materials,constructed a set of evaluation index system,and further proposed a comprehensive evaluation method based on AHP-TOPSIS,and selected reinforced concrete pipes and HDPE double-wall Corrugated pipes and UPVC double-wall corrugated pipes are targeted for empirical application evaluation.The results of the study are as follows:Sort out the existing domestic and foreign drainage pipe evaluation research index systems and the requirements of design guidance documents for pipe selection,and propose an evaluation index system.Among them,the target layer is the priority for the selection of drainage pipe materials,and the criterion layer is technical performance indicators,economic cost indicators,and environmental impact indicators.The indicator layers include corrosion resistance,interface reliability,mechanical performance,construction convenience,pipe quality reliability,and hydraulics.9 indicators including performance,life cycle cost,life cycle environmental impact,and pipeline leakage environmental impact.Established a comprehensive evaluation method combining AHP and TOPSIS.The analytic hierarchy process is combined with expert scores to determine the weights of various indicators.Technical performance indicators are assigned by fuzzy comprehensive evaluation.The quantitative indicators of pipe quality and hydraulic performance indicators are determined by membership functions.The qualitative indicators include corrosion resistance,interface reliability,mechanical performance,and construction methods to determine the values through expert scores;Life cycle cost indicators calculate the cost of each stage in the life cycle by establishing a pipeline engineering model and a pipeline degradation model,and convert them into annuities.Life cycle environmental impact indicators are established through simapro9.0 software to calculate the impact of pipes on human health,ecosystems,and resources during the life cycle of pipes,and these impacts are unified into a single score;the environmental impact of pipeline leakage is measured through the defect area of the pipe and the sewage per unit area.The leakage volume is estimated.The comprehensive evaluation is synthesized by the TOPSIS method according to the index weight and value.Taking the specific engineering model as the object,three kinds of pipe materials:reinforced concrete pipe,HDPE double-wall corrugated pipe and UPVC double-wall corrugated pipe were selected to conduct a comprehensive evaluation case study on the selection of pipe materials.The evaluation results show that the relative closeness of the three types of pipes is 0.608(HDPE double-wall corrugated pipe)>0.550(UPVC double-wall corrugated pipe)>0.412(reinforced concrete pipe).HDPE double-wall corrugated pipe is the best choice under the background of the engineering model.This paper proposes a new method for drainage pipes,which can comprehensively consider the technical performance,economic cost,and environmental impact of the pipe life cycle,and realize the priority of the selection of different pipes.It can be used as Decision support tool of selecting drainage pipes for designers and managers.