You, X (2010) Risk analysis in tunneling with imprecise probabilities. PhD thesis, University of Texas at Austin, USA.
Abstract
Due to the inherent uncertainties in ground and groundwater conditions, tunnel projects often have to face potential risks of cost overrun or schedule delay. Risk analysis has become a required tool (by insurers, Federal Transit Administration, etc. ) to identify and quantify risk, as well as visualize causes and effects, and the course (chain) of events. Various efforts have been made to risk assessment and analysis by using conventional methodologies with precise probabilities. However, because of limited information or experience in similar tunnel projects, available evidence in risk assessment and analysis usually relies on judgments from experienced engineers and experts. As a result, imprecision is involved in probability evaluations. The intention of this study is to explore the use of the theory of imprecise probability as applied to risk analysis in tunneling. The goal of the methodologies proposed in this study is to deal with imprecise information without forcing the experts to commit to assessments that they do not feel comfortable with or the analyst to pick a single distribution when the available data does not warrant such precision. After a brief introduction to the theory of imprecise probability, different types of interaction between variables are studied, including unknown interaction, different types of independence, and correlated variables. Various algorithms aiming at achieving upper and lower bounds on previsions and conditional probabilities with assumed interaction type are proposed. Then, methodologies have been developed for risk registers, event trees, fault trees, and decision trees, i.e. the standard tools in risk assessment for underground projects. Corresponding algorithms are developed and illustrated by examples. Finally, several case histories of risk analysis in tunneling are revisited by using the methodologies developed in this study. All results obtained based on imprecise probabilities are compared with the results from precise probabilities.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Thesis advisor: | Tonon, F |
| Uncontrolled Keywords: | cost overrun; groundwater; tunnel; risk analysis; risk assessment; probability; risk analysis |
| Index terms: | risk assessment, decision tree, interaction, schedule delay, judgment, engineer, cost overrun, methodology, evidence, risk analysis, history, tunnel, groundwater, face, risk register |
| Subjects: | evaluation and assessment methods, profession, dispute resolution, psychology, financial and cost management, architectural and construction history, research methods, water management, financial risk, project controls, decision analysis, infrastructure and transport systems, environmental hazards, behavioral psychology |
| Topics: | Engineering Principles, Risk Management, Sustainability, Legal Issues, Cost Management, Research Practice, Roles and Professions, Organizational Design, Time Control |
| Descriptive scope: | 4 PCTA |
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