The use of seismic refraction method in slope failure investigation

This study is focused on a slope failure investigation for a site of Semantan Formation located at the Temerloh-Mentakab route, Pahang. Ground investigation employing seismic refraction survey was conducted followed by trial pits, Macintosh probe and wash drilling with standard penetration tests (SPT). Laboratory tests that includes classifications, drained shear box and consolidated undrained triaxial with pore pressure measurements were also carried out. The results of the velocity profile from several spread lines have indicated a possible shallow failure from a weak soil material that overlie a deeper sliding failure mass. The two possible sliding surfaces interpreted from the seismic velocity profiles were found to correlate well with the Macintosh probe and the SPT conducted on adjacent boreholes. A lateral variation in the velocity profiles from several spread lines have shown that the dominantly argillaceous material could be delineated from the dominantly arenaceous material that has been unaffected in the slide and conforms well with the geological facies of the site. The topography of the post failure ground level and the probable slip surface, interpreted from the seismic refraction profiles were then represented using a 3-D graphic software in order to evaluate the overall sliding mass