Reliability analysis of pile-founded T-walls using the random variable method and random field method

Abstract

The pile-founded walls (e.g., T-walls) are important civil infrastructure for flood protection. The stability analysis of floodwalls in the face of flooding hazards is a critical problem for the design and maintenance of floodwalls. However, most current studies for the stability assessment of floodwalls are based on deterministic analyses. The uncertainties of soil properties, which cannot be avoidable due to complex geological processes and depositional environment, are not sufficiently studied. To address the uncertainties of soil properties, a two-dimensional pile-founded T-wall system with several clay layers on the top and a sand layer on the bottom is taken as an example for the reliability analysis. Both the random variable method and random field method are adopted for the probabilistic analysis of floodwalls. The effect of the coefficient of variation (COV) and scales of fluctuation of soil properties are investigated by parametric studies. The results show that the probability of failure increases with the COV of soil properties for both methods. For the random field method, the effect of the vertical scale of fluctuation of soil properties is more profound than the horizontal scale of fluctuation. The probability of failure derived from the random variable method is generally larger than that from the random field method at high flood water elevations when the same COV of soil properties is applied. This study can provide useful references for risk-informed decision-making in the stability assessment of floodwalls in the face of flooding hazards.