Suripto, Putera Agung Maha Agung, Sutikno, Aldo Wirastana Adinegara, Muhammad Fathur Rouf Hasan, Armin Naibaho, Faisal Abdullah
Indonesia experiences not only extreme fluctuation in temperature and rainfall intensity, like in Langsa District, Indonesia, but also temperature and rainfall changes due to climate change, which can be a trigger for slope stability. Infiltration of water during the precipitation process on unsaturated expansive residual soil types can create a significantly unstable situation in the slope zone, caused by an increase in pore water pressure in the short term. The study aims to determine the magnitude of deformation and the safety factor (SF) using the Bishop and Morgenstern methods for slope stability conditions. The analysis considered pore water pressure (PWP) at the soil water characteristic curve (SWCC) during dry and rainy seasons. One of the important things to evaluate slope stability and/or all deformations is the laboratory grain-size distribution of the existing soil mass. Climate variations may cause significant swelling and shrinkage due to changes in water content and grain size, which can trigger initial movements at the toe of the slope. A susceptible soil layer was identified between depths of 0.0 and 6.0 m. The critical SF during wetting, representing rainfall infiltration, was found to be SF = 1.543, whereas during drying or evaporation in the dry season, it increased slightly to SF = 1.566. It was discovered that the SWCC shape changed significantly at fine-grain content above ±20–30%, characterized by an increase in AEV and residual water content, leading to a nonlinear decrease in unsaturated permeability. Different SWCCs across layers are caused by variations in particle size with depth. ©2026 The authors.
Department of Civil Engineering, Politeknik Negeri Jakarta, Depok, 16425, Indonesia; Graduate School, Universitas Brawijaya, Malang, 65145, Indonesia; Department of Civil Engineering, Politeknik Negeri Malang, Malang, 65141, Indonesia; Department of Civil Engineering, Politeknik Negeri Lhokseumawe, Lhokseumawe, 24301, Indonesia
