Two-dimensional slope stability analysis of earthen levee strengthened by articulated concrete block system under hurricane overtopping flow conditions

Abstract

A critical component of the evaluation of safety of earthen levees is the consideration of their global stability during hurricanes. Very little information is available regarding the slope stability of levees during hurricane overtopping conditions involving storm surge and wind generated wave action. In this research, a comprehensive slope stability investigation was undertaken where an earthen levee, representing full scale overtopping conditions, was subjected to storm surge only overflow, wave only overtopping, and combined wave and surge overtopping conditions. The crest and the landside of the levee were strengthened by the articulated concrete block (ACB) system to protect against overtopping. This paper presents a conceptual model for ACB strengthened levee as well as a methodology for analysis and incorporation of various hurricane overtopping flow conditions in levee slope stability evaluation. The results of this study indicate that ACB strengthening systems increase the stability of the levee significantly during all the overflow conditions, especially wave only overtopping as well as combined storm surge and wave overtopping conditions. The findings of this study show that the slope stability of both the natural and the ACB strengthened levees decreases with larger equivalent random wave pressures. However, during the storm surge conditions, the factor of safety decreases as a result of higher surge regardless of the magnitude of equivalent random wave pressure. In addition, it has been shown that the effect of duration of random wave pressure on the stability of the ACB strengthened levee is limited.