Numerical simulation of T-walls supported by batter piles within a levee embankment

Abstract

After catastrophic levee failures triggered by the 2005 Hurricane Katrina, concrete T-walls with batter piles are extensively used to enhance the integrity of levees in the New Orleans area. Since the foundation soils in this region typically include soft and compressible clays, T-walls with batter piles should be designed to account for bending moments and stresses induced by settlement. However, the current T-wall design procedure for estimating these settlement-induced bending moments (SIBMs) only takes a limited range of conditions into consideration. This paper presents results from a series of finite-difference numerical simulations to investigate the effects of various parameters on SIBM in pile-supported T-walls. The numerical model was first used to simulate a centrifuge test and upon comparison, a reasonable agreement was observed between the numerical simulation and experimental results. The numerical model was then used to investigate the effects of different parameters including pile connection fixity, batter, and stiffness of the pile on SIBM. The simulation results showed that the fixed connection greatly increases the bending moment compared to the pinned case. The difference in the maximum bending moment due to different pile batters can be approximated linearly. However, the results showed that changes in the maximum bending moment versus pile stiffness do not follow a linear pattern. Findings of this research can be used to validate or identify the need for possible adjustments in the current T-wall modelling and design methodologies.