Modeling Seepage Effects In Heterogeneous Soil Under Heading-Up Structures Using An Experimental And Numerical Methodology

Abstract

Seepage of water under the aprons of heading-up structures is one of the most important factors that should be carefully studied while designing any heading-up structure. Seepage can cause different problems related to uplift pressure and undermining and piping. These problems threaten the stability of the structures and can lead to their failure. In nature, soil is normally heterogeneous rather than uniform. One of the special cases of soil heterogeneity is stratified soil where soil layers are usually horizontal as most soils deposit in this manner. This study introduces a new electric analogue experimental modeling methodology to simulate the effect of soil stratification under the apron of heading-up structures on the safety against uplift and piping. This is achieved through making different scenarios for the hydraulic conductivity values of the layers and their configurations under the apron. Both SEEP2D and electric analogue models are applied to study seepage under heading-up structures occurring on both a single layer and stratified soils.The two models are compared to check the accuracy of the electric analogue in simulating seepage in a trial to add more verification cases of the electric approach. The results showed that the pressure distribution under the floor of heading up structures is actually non-linear, and accordingly, the linear assumption can be a weak assumption to study seepage under large heading up structures and dams. Stratification is found to affect the head distribution under the apron, and the total flow rate.