Reliability analysis of bucket foundation breakwater considering water-level variations under complex natural conditions

Abstract

Bucket foundation breakwater is a new type of structure suitable for deep water, strong waves, soft ground and other complex natural conditions. At present, the research on bucket foundation breakwater focuses on the failure mode and stability, and further research on the reliability is needed to promote the application of this structure. Based on the massive field monitoring data that lasted nearly seven years of bucket foundation breakwater in Xuwei Port Area of Lianyungang Port, China, the statistical analysis was carried out according to the bimodal distribution. The composite limit state equation of the structure was established by using the analytic hierarchy process. At the same time, three single failure modes of slip, settlement and overturning, as well as composite failure modes were simulated by Monte-Carlo method, and the influence of the water-level variations on structural reliability were further studied. The results showed that, with the increase of water-level, the rotation center of bucket foundation breakwater gradually moves to the harbor side. Furthermore, due to the increase of overturning moment and the decrease of structure weight, the reliability of bucket foundation breakwater decreases, but it still has a high reliability. The possibility of slip failure is greater than that of overturning failure, and the settlement failure can usually be ignored. It is recommended to use the designed average water-level, establish the composite limit state equation of the structure based on the analytic hierarchy process, and conduct the structural reliability analysis according to the composite failure mode by Monte-Carlo method to obtain reasonable and accurate results.