Abstract
Tropical countries are prone to slope instability due to the presence of residual soil, especially under rainfall loading. Past studies only depended solely on laboratory testing or numerical analyses or field instrumentation or two combinations between either of them to assess the stability of residual soil slope. The objective of this study is to develop the integrated framework combining instrumentation reading, laboratory testing, and numerical modelling based on unsaturated soil mechanics principles to assess the residual soil slope stability related to shallow slope failure. The investigation reveals that instrumentation readings align closely with numerical seepage analysis, with the wetting front occurring at a depth of 0.55m after 72 hours. Stability analysis, evaluated using PLAXIS 2D (finite element) and GeoStudio (limit equilibrium), indicates a variance of 6.25% before and 2.97% after rainfall between two methods. Numerical analyses with unsaturated soil mechanics are required to ensure stability and deformation meet the requirement.