Worth of the three dimensional simulations of seepage in the vicinity of heading-up structures

Abstract

This paper evaluates the three dimensional effects in studying seepage in the vicinity of heading up structures. An artificial heading-up structure installed on pervious soil is studied using both a 3D model (Seep3D) and a vertical 2D model (SEEP2D). The uplifts under the apron and the exit gradients resulting from both models are compared for different structure configurations including the presence and lack of sheetpiles for both laterally homogeneous and heterogeneous conditions. In addition, the effects of downstream wing walls (guide walls) on seepage are also assessed. The results showed that the exit gradient in the 3D simulations can reach almost double its value in the 2D simulations in different configurations. The existence of downstream guide walls can also lead to significant increase in the exit gradient. The paper proves that studying seepage in 3D can significantly become critical over the traditional 2D approach especially in cases of significant lateral heterogeneity.