Numerical Analysis of Slope Stability for Soil-Cement Improved Slopes Using Finite Element Method

Abstract

Landslides are a problem in northern Thailand, characterized by alternating plains and steep mountainous terrain. Soil cement stabilization has gained popularity as a solution to mitigate this issue. This research investigates the changes in the properties of embankment soil at varying cement mixing ratios. Cement was mixed at proportions of 8%, 10%, 12%, 14%, and 16% by dry unit weight of soil. The properties of the cement-soil mixtures were tested and compared with those of the original soil in the laboratory. The stability of the slope, expressed as the Factor of Safety (F.S.), was analyzed using PLAXIS 2D Version 2020. The results showed that the unconfined compressive strength and shear strength of the soil increased with increasing cement content. The analysis of the F.S. indicated that soil cement stabilization improved slope stability. Specifically, cement mixing ratios of 8-10% by dry unit weight of soil increased the F.S. by approximately 22%, ratios of 12-14% increased the F.S. by approximately 27%, and a ratio of 16% increased the F.S. by approximately 30% compared to the untreated original soil.