供水管网多目标更新优化模型研究-环境工程专业论文.docxVIP

ABSTRACT Water distribution systems (WDS) as vital urban facilities play an important role in the modern life and urban developments. In many cities in China, the operation of mains suffers from such problems as leakage, pipe failure, pressure fluctuation, contamination and so on, which results in reduced level of service. Research the subject of rehabilitation strategies for mains do really make sense. A decision support system for rehabilitation policy-making is formulated in this thesis, with operations research, system engineering, reliability theory, optimization theory, mathematics and computer technology involved flexibly. Optimal sort of pipes to be restored in mains is illustrated. In this section,pipes are divided into two sets. Primary set is retrieved from the candidate set by topology reliability, and the rest part is so called secondary set. Then total influenced flow and weighted sum of pressure and quality reliability are separately defined as failure strike level for the two sets here and programed with EPANET engine. The probability of pipe failure and the probability of accident are formulated. The two sets are sorted based on Bayesian decision method. The event score is failure strike level and the probability is formulated by reliability theory. Finally, optimal rehabilitation sort are formulated based on some provisions such as threshold break rate and corrosion level and models above. Positive result was derived here. Optimal rehabilitation scheduling for the whole network is illustrated, aiming to get optimal pipe set and size choice. As a muti-objective optimal problem, trade-offs among total cost, failure strike level of the mains, pressure reliability and quality reliability are considerd as four independent goals here. GPU parallel computing based numeration method is structured here first to solve the muti-objective problem. NSGA-II and GPU parallel computing are both used to solve the example problem for comparison. It was shown that G