The hybrid Fuzzy Fault and Event Tree analysis in the geotechnical risk management in HDD projects

Abstract

ABSTRACT Horizontal Directional Drilling (HDD) technology is one of the most popular trenchless construction methods for installing pipelines under various obstacles. The geotechnical risk level of HDD projects is one of the key parameters when assessing the project feasibility and making costing of the project. It is also a starting point for introducing the geotechnical risk management strategy which aims to reduce the number of installation failures and their negative consequences. The objective of this work was to develop a new geotechnical risk management model for HDD projects. The risk management process was carried out applying the hybrid Fuzzy Fault and Event Tree analysis. Applying the fuzzy set theory in the proposed model made it possible to decrease the lack of precision and difficulties with gaining the crisp values of the basic events probability, which occur in the conventional Fault Tree Analysis. It allowed to model risk management actions clearly and effectively. Forty-seven risk remediation strategies for all the identified geotechnical risks were proposed. Four types of risk response strategies were considered: risk retention, risk transfer, risk elimination and risk reduction. The practical application of the proposed risk management model for HDD projects was shown on four examples.