A Probabilistic Risk Assessment Approach for Surface Settlement Caused by Metro Tunnel Construction Using Credal Network

Abstract

The epistemic uncertainty of geological condition, hydrological condition, and human factors causes the risk assessment result of metro construction to be imprecise. To reveal the epistemic uncertainty, a probabilistic risk assessment approach for metro construction is proposed based on the credal network. The epistemic uncertainty of risk factors is described by prior probability and conditional probability. Based on the scarcity of available data, prior probability is quantified by interval probability and probability box, and conditional probability is qualified by imprecise leaky noisy-OR model and imprecise Dirichlet model. Taking the shield tunnel projects of Beijing Metro Line 14 as the research object, the proposed approach and the conventional approach without considering epistemic uncertainty were adopted to predict the risk probability of surface settlement caused by shield tunnel construction. The predicted results were compared with the statistical probability derived from Peck formula and the field monitoring data, which verifies the rationality and effectiveness of the proposed approach.