Risk assessment of the buried pipeline based on the fault tree and fuzzy theory

Based on the accumulated engineering data of Changzhou Gas Company, the fault tree of failure for the buried pipeline is established. The major factors of failure for the buried pipeline are determined as the third-party damage, corrosion, pipeline defects, management and improper maintenance. Forty-eight elementary events led to failure of the pipeline are obtained. Integrating the fault tree method into the fuzzy comprehensive assessment method, the risk assessment model for the buried pipeline is established.The risk assessment steps are as follows: (1) the major factors to impact the failure of the buried pipeline are used as the factor set of fuzzy comprehensive assessment model for buried pipeline; (2) the grade membership of factors for every bottom evaluation index of fault tree, judgement matrix and weight set of single factor are established, and (3) to achieve the judement set of single factor and entire evaluation result are made. A case shows that the risk assessment of buried pipeline results obtained by this model is in line with the actual event. It is considered that this model can provide a base in scientific management to other urban gas companies.