At-rest lateral earth pressure coefficient under narrow backfill widths: A numerical investigation

The lateral earth pressure at rest is typically considered in situations where lateral wall movements are negligible. Determining the coefficient of lateral earth pressure at rest (referred to as K₀) often relies on established classical equations. However, these equations often overlook the influence of the width of the backfill soil on lateral earth pressure. While this omission is generally acceptable when the backfill soil is wide enough, there are instances where a retaining wall supports backfill soils of limited width, such as basement walls between adjacent buildings. Yet, there is limited research addressing the impact of narrow backfill in such scenarios. We aimed to address this gap by investigating variations in K₀ values under different conditions, including backfill width and soil properties. Using ABAQUS for numerical simulations, we refined and validated our model using relevant laboratory experimental data. Subsequently, the validated model was applied to various simulation scenarios. For narrow backfill widths (ranging from 0.1 to 0.7 times the retaining wall height), our findings indicated a general decrease in K₀ values with decreasing backfill widths, often smaller than those estimated using classical equations. Additionally, along the depth of the wall, K₀ values tended to decrease with increasing depth for narrow backfill widths. These findings contribute to our understanding of the impact of narrow backfill on K₀.