Resilience of MSE Walls with Marginal Backfill under a Changing Climate: Quantitative Assessment for Extreme Precipitation Events

Abstract

Climate change is expected to alter statistics of extreme events in the future. Adapting geotechnical infrastructure to a changing climate necessitates quantitative assessment of the potential climate change impacts on the performance of infrastructure. This study numerically investigates the hydromechanical response of a mechanically stabilized earth (MSE) wall constructed with marginal backfill to extreme rainfall events under a changing climate. The need for investigating the effects of extreme precipitation on marginal backfill is more pronounced because larger matric suction can be developed in such backfills. To address this need, this paper compares the performance of an MSE wall using two sets of rainfall intensity-duration-frequency (IDF) curves, denoted as baseline and projected, for the Seattle area. The baseline IDF curves are provided by the National Oceanic and Atmospheric Administration (NOAA) and currently used for design purposes, and the projected IDF curves are obtained using 20 climate model simulations of the future. The results show that use of the baseline IDFs can lead to underestimation of the wall deformation and loads carried by reinforcements. The results highlight the importance of site-specific assessments to quantify the potential impacts of climate change on the performance of current and future MSE walls. Such consideration gains even more importance considering the increasing interest in using marginal backfills in earth retaining structures due to economic and environmental considerations.