The Effect of Soil Layers Thickness and Characteristics on the Efficiency of Sheet Piles under Heading-Up Structures

Abstract

Using sheet piles under the floor of a heading-up structure decreases the flow rate, uplift force, and hydraulic gradient, and increases the structure’s safety. The type of soil under the structure is an important factor in the seepage analysis. In this study, a 2D numerical model is used to simulate the flow under the floor of a heading–up structure resting on two soil layers of unequal thicknesses. The floor is considered to have vertical and inclined sheet piles with different configurations. The model was first validated using experimental data from a previous research, then applied to study different scenarios for the thicknesses and hydraulic conductivities of the soil layers. Various locations and inclination angles of the sheet piles are also studied. The study highlights the effect of the soil layers thicknesses and characteristics on the efficiency of the sheet piles in reducing the flow rate, uplift force, and exit gradient. The results show that such soil properties have a great effect on the efficiency of sheet piles. It is strongly recommended to consider the effect of the soil characteristics as well as the thickness of the upper soil layer relative to the sheet pile’s depth in the floor’s design.

Keywords: Heading-up structures; Seepage; SEEP2D numerical model; Soil layers thickness; Soil characteristics; Vertical and inclined sheet piles.