Matric suction characteristics of unsaturated residual soils at the Naketiya landslide site

Abstract

This paper discusses the experimental determination of some matric suction characteristics of residual soils from Naketiya landslide site, Badulla District, Sri Lanka. The test programme required the modification of the triaxial test apparatus using high air entry disks so that pore-air and pore-water pressures of a soil sample could be maintained at required magnitudes. Samples were made from soil obtained from the Naketiya landslide site, and these were tested in triaxial conditions under different matric suction values. The shear strength function and the soil-moisture characteristic curve for the soil are developed. These results are of importance in interpreting the variation of shear strength with the moisture content for the residual soil at Naketiya, which will have a direct bearing on stability of the slopes there.