Thesis (M.Sc.)--Chulalongkorn University, 1989

This study was done on the Prachinburi-Khao Yai Highway (3077) between KM. 11 and KM. 15.3 where it passes through a colluvial slope. Between KMs. 12.658 and 12,765, the foundation failures has occurred repeatedly on this embankment three times in 1981,1983 and 1985/1986.The reconnaissance and detailed geologic, geotehnic, geomorphologic and hydrologic investigations were done to analyze and evaluate the stability and causes of failures of the embankment on the colluvial slope.The slope stability was analyzed in terms of effective stress by limit equilibrium and categorized into 3 stages, namely the preconstruction state, the stages of embankment failures in 1983 and in 1985/1986. Different mode of failures were thus recommended and compared. The results of the investigations revealed that the failures occurred as the embankment was built on the active natural landslide scarp which indicates a progressive failure in the colluvial mass.