Determination of Replacement Material Thickness in the Case of Expansive Soil in Dams

Abstract

One simple solution to reduce the impact of damage caused by swelling on expansive soil is to replace it with soil that has better properties. Unlike replacing expansive soil material in the subgrade or foundation layer, replacing expansive material in a constructed dam requires special consideration, as fluctuating reservoir water levels and rainfall cycles affect the active zone of expansive soil, which will affect the stability of the dam. Therefore, this study was conducted to determine the thickness of the replacement layer, which is also the active zone of expansive soil in the dam, by modeling the stability of the dam against changes in reservoir water levels and rainfall cycles with parent analysis using finite element and limit equilibrium method programs. One example of dam damage caused by expansive soil was used as a case study. The study results show that changes in the wet-dry active zone can be used as a basis for determining the thickness of the replacement material in cases of expansive soil in dams.