Thispaper presents an assessment of arock planar slide,which took place at km108alongtheTienYen-MongCaiexpressway, anextensionoftheHalongVandon expressway in Vietnam.Half ofthe expressway has been covered by a large volume of rock deposit after its movement.

This study utilizes Geo-Slope 2D to evaluate slope stability along Route 14G, integrating soil characteristics and historical rainfall data to analyze the slope stability based on the Factor of Safety (FoS). Key findings highlight the significant role of Soil-Water Characteristic Curves (SWCCs) and permeability coefficients in determining slope responses to varying rainfall levels.