| Underground utility infrastructure, a very substantial and crucial part of our urban underground space, has been built up progressively over the last 100 years or longer. It represents a major investment in both of developed and developing countries, what' more it underpins all modern economies activity and daily living. It consists of transport systems, water supply, waste disposal, energy distribution, telecommunications and recreational networks. However, due to the technical difficulty in inspection and rehabilitation in the non-man access pipeline system, the asset structure condition and performance efficient are usually deemed to good or acceptable until there are some visible failures, defects or accidents, such as pavement settlement, leakage, even if collapse. What's more, the pipe condition and performance declines rapidly without timely maintains and rehabilitation. It is report that the average age of underground infrastructure is 47 years, and maximum age of greater than 100 years (Mailik, et al.,1997). Aging is a fact of life, and structural failure typically occurs over a long time. Sometimes, the underground pipelines also fail earlier due to hydraulic overloading, live loading, corrosion, and other deterioration.Underground pipeline asset management is designed to address these problems mentioned above and maximum the benefit of municipality investment by processing underground infrastructure information, taking a lifecycle approach, minimizing the failure risk, improving implementation effective and helping engineer to make decision.Pipeline performance rating model consists of four procedures:defects identify, rating policy, defects weight and final formula. The evaluation value of pipeline performance rating helps municipalities and engineers to understand the conditions of underground pipeline system and then make decisions if the pipeline needs emergent repair or rehabilitations to keep acceptable performance efficiency. A new weight definition approach by linear regression analysis on statistical data is put forward for more detailed and precise performance rating in this dissertation. For risk prediction, a modified approach is presented to model the deterioration of buried infrastructure assets by using a fuzzy rule-based, non-homogeneous Markov process. This deterioration model yields the 'possibility' of failure at every time period along the pipe life. The use of fuzzy sets and fuzzy techniques help to incorporate the inherent imprecision and subjectivity of the data, as well as to propagate these attributes throughout the model, yielding more realistic results. Underground infrastructure management is not only a multi-discipline field over physics, chemistry, mechanics, economics, statistics and mathematics, but also consists of different research directions such as rehabilitation materials, rehabilitation approaches, risk management, pipe evaluation, life-cycle analysis, and so on. However, this dissertation will focus on two primary research directions, performance rating and risk management based on three projects that author have involved, "An Asset Management Approach for Drainage Infrastructure and Culverts" and "Use of Trenchless Technologies for a Comprehensive Asset Management of Culverts and Drainage Structures" in CUIRE from 08/2007 to 02/2009, "Trenchless Assessment Guide based on Web-site" at TTC from 03/2009 to 09/2009, and "Underground Pipeline asset management based on Trenchless Inspection and Rehabilitation" in CUG from 10/2009-03/2010. Performance rating is critical part of underground pipeline asset management, which helps municipalities and engineer to understand the pipeline system by inspection methods. What's more, it also is viewed as the technical information for further inspection schedule and rehabilitation invest. Risk management is hot research over developed countries, viewed as the primary process for stability analysis, decision-making of rehabilitation, life-cycle analysis on investment of underground pipeline system.Chapter 1 presents normal conception of Underground Pipeline Asset Management, so called Underground Infrastructure Asset management, which usually consists of organisation strategic plan, asset management policy, asset management processes, implement asset management solutions, asset data and information systems. Developed countries have put underground pipeline asset management a high important place since last century, and government, industry, research institutes have involved this field, such as EPA, Department of Transportation of Unite states (DOT), National research Council Canada (NRCC), University of Texas at Arlington (UTA), National Trenchless Technology Cent (TTC) and so on.Chapter 2 reviews these surveys and researches on pipe condition and performance rating over the world. There are various researches and rating models for condition and performance rating in different states or countries. Section 2.1 introduces pipe inventory including most of pipe information during pipe installation. Section 2.2 gives a normal idea about condition assessment model. Section 2.3 lists the problems with the development of underground pipeline asset management and also points out benefits to develop UPSM in China.In Chapter 3, Pipeline Performance Rating Model is designed and developed with four important steps, defects identify, rating policy, defects weight and final formula. Section 3.1 gives a simply introduction to performance rating development. Section 3.2 lists all of the defects that could lead to pipeline failure of different distribution system. Section 3.3 and section 3.4 discusses the failure mechanics of structure defects and capacity defects separately. Section 3.5 presents two defects weight defining methods, subjective and data-based. Section 3.6 develops the formula to rating the pipeline performance according to the condition-if-then table and defect weight. Section 3.7 gives a summary for this chapter.In Chapter 4, a modified risk prediction approach is put forward to evaluate the deterioration of buried pipeline by using a fuzzy rule-based, non-homogeneous Markov process. This deterioration model yields the 'possibility' of failure at every time step along the life of the asset. Fuzzy sets and fuzzy techniques help to incorporate the inherent imprecision and subjectivity of the data, as well as to propagate these attributes throughout the model, yielding more realistic results. Section 4.1 introduces the widely-using risk model and points out the problem with this model, while section 4.2 collects two useful algorithm and principle for further researches. Section 4.3 develops detailed Deterioration Probability Markov Chain based on information of section 4.2, and then section 4.4 modifies this model to match the real situation of pipe defect deterioration process by adding thresholds. Section 4.5 applies the modified Markov Deterioration model to six different pipe structure defects to validate this mode. Section 4.6 gives a summary of Chapter 4Chapter 5 gives a general summary, analyzing the benefits to develop Underground pipeline asset management, pointing out research direction for China and listing Innovations in this dissertation: data-based defects weigh definition and modified fuzzy Markova deterioration model.
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