Study On Safety Risk Assessment Of Mining Method Based On Fuzzy Fault Tree

In order to study the safety risk assessment of mine tunnel construction,a more perfect and applicable evaluation model is established.Firstly,this paper try to identify the risk and build a risk assessment index system by using WBS-RBS risk matrix which considers risk factors and construction steps.Secondly,the preliminary risk assessment method is established on index system,and a special and general risk assessment method is established on fuzzy fault tree theory.Finally,it is applied to engineering examples.The main research results are as follows:(1)This paper demonstrates the rationality of using fuzzy fault tree to evaluate the safety risk of mine construction.Firstly,the emergence and development of the risk management and the situation of mountain tunnel risk assessment are discussed to reveal some problems in the study of risk assessment of mountain tunnel.Secondly,the risk assessment methods and mountain tunnel construction methods are summarized,and the mining method is determined as risk assessment.At last,considering the problems existing in the research about the risk assessment of the mining method,the characteristics of the risk assessment method and the peculiarity of the tunnel construction method,choose to use the fuzzy fault tree to evaluate the safety of mine construction.(2)To distinguish the risk source of construction,the risk identification matrix is established on the work breakdown structure and risk breakdown structure.According to the construction characteristics of the mining method,the working procedure of the mountain tunnel construction is decomposed by using work breakdown structure;the risk from many influence factors such as environment,design,construction and management is decomposed by using risk breakdown structure.Then,WBS-RBS coupling matrix is formed,which is used to identify the risk events.Finally,the general safety risk assessment index for tunnel construction by mine tunneling method is established.(3)Special and general risk assessment method is established on fuzzy interval.Firstly,the expert estimation results are transformed into fuzzy sets by using fuzzy mathematics theory.Secondly,considering the confidence of experts and the weights of experts,the modified fuzzy set is corrected based on the confidence index method to improve the accuracy of risk analysis.Finally,this paper proposes the concept of fuzzy safety importance and considers the impact of risk probability and risk loss of fault tree quantitative analysis,and then the fuzzy safety important degree is obtained and the risk level is determined according to the level of risk standard.The evaluation model is applied to engineering practice.The risk assessment model is applied in the evaluation of the construction of Maluan mountain tunnel.The evaluation conclusion and practical engineering have high similarity,which verify the mining method of tunnel construction safety risk assessment model has good availability and pertinence.