Centrifuge modeling of geosynthetic-reinforced soil retaining walls subjected to the combined effect of earthquakes and rainfall

Local fine-grained soils were usually used as backfill for geosynthetic-reinforced soil retaining walls (GSRWs). However, there are few studies on the seismic response in this case, especially under the influence of rainfall. In this study, three centrifuge shaking table tests were performed at 30 gravities to investigate the performance of GSRWs subjected to the combined effect of earthquakes and rainfall. Two stages were designed in this study. In the first stage, three conditions were simulated, i.e., post-rainfall earthquake (Test-1), rainfall and earthquake occurring simultaneously (Test-2), and post-earthquake rainfall (Test-3). The results show that if there was enough time for rainwater seepage, the suction force generated in unsaturated GSRW enhanced the soil strength. When GSRW was subjected to heavy rainfall and no time for seepage, the deformation of the GSRW was largest due to the high excess pore water pressure of local saturated soil in GSRW. In the second stage, seismic failure models of GSRWs with different water contents were studied. Under the excitation of a series of continuous earthquakes, a large tensile crack was formed in the unsaturated GSRW, whereas no cracks were found in the saturated GSRW, but its panel demonstrated a large bulging deformation. •Centrifuge shaking table tests were performed to investigate the behavior of geosynthetic-reinforced soil retaining walls subjected to the combined effect of earthquakes and rainfall.•Three conditions (post-earthquake rainfall, rainfall and earthquake occurring simultaneously and post-rainfall earthquake) were simulated, covering all possible situations in practice.•Seismic deformation and failure modes of unsaturated and saturated GSRWs were revealed.•The applicability of acceleration prediction in current design guidelines was discussed.