Performance-based Engineering Risk Management And Application To Risk Evaluation In Metro Construction

Metro construction is blossoming in recent decades,and the risk management of metro engineering is significant because of the high risk in metro construction.Thanks to the research and application in decades,the engineering risk management is approaching maturity,and the corresponding guideline and code have been filed.However,the existing ideas and methods of engineering risk management have some deficiencies.The improvement to these deficiencies and the perfection of engineering risk management are necessary.Aiming at these problems,this thesis summarizes the existing ideas and methods for engineering risk management,the deficiencies and the corresponding improvement proposals are ascertained,with the developments being as follows:1.Improvement and optimization of risk loss classification criteriaChinese current national code “GB 50652-2011” defines risk loss classification criteria explicitly.Risk loss is classified into five categories,with each being explicitly defined as quantitative criteria.However,the risk loss classification criteria do not involve all fields of risk loss,nor be carried out conveniently due to the characteristics of metro construction.With these deficiencies,the risk loss classification criteria are updated and optimized using Performance-based Earthquake Engineering(PBEE)idea.The severity level of risk loss is classified by means of the performance level concept in PBEE idea,and Performance-based risk loss classification(PBRLC)is proposed.PBRLC defines risk loss category based non-uniform criteria and measures risk loss severity based quantitative criteria.Risk loss classification is ascertained based on the characteristics of engineering problem and the demands of engineering owner.2.Proposal for Performance-based engineering risk managementPerformance-based engineering risk management idea(PBRM)is proposed based on current engineering risk management procedure.PBRLC is selected as the principal index.The procedure of PBRM is the same as current risk management procedure and it contains risk delineation and identification,risk estimation,risk evaluation,and risk control.PBRM idea accords with the diversity and relativity of engineering risk,leading to the definition for risk loss being simplified and accordance with the actual demand in engineering construction.Moreover,the execution for PBRM must integrate widely the existing theory and technology,so thatit can be accepted simply by engineering construction.3.Proposal for Performance-based risk dynamic evaluation method in metro construction.Considering the deficiency of existing risk evaluation methods for metro construction,Performance-based risk dynamic evaluation(PBRDE)method for metro construction is proposed based on PBRM idea.PBRDE selects the dynamic monitoring data during metro construction as the major index of risk evaluation,and analyzes monitoring data by SPC method,so that the traditional risk evaluation method is improved.PBRDE calculates the probability of risk loss through process capacity index(PCI)analysis of SPC method,and the risk level is ascertained.Moreover PBRDE identifies the characteristics of risk variation by statistical control chart(SCC)analysis of SPC method,and the ultimate risk decision measures are ascertained by applying PCI analysis and SCC analysis.PBRDE selects PBRLC as the risk loss index,and risk loss is defined explicitly.The dynamic randomness of process is analyzed based on statistical inference by introducing SPC method,which renders risk dynamic evaluation to be executed scientifically.