INVESTIGATION OF FAILURE OF HIGHWAY EMBANKMENT FOUNDED ON COLLUVIUM AND SUGGESTED STABILIZATION MEASURES FOR RECONSTRUCTION

The landslide at km 38 + 600 along the Irbid-Amman Highway in Jordan was the result of foundation instability during the exceptionally heavy rainfall season of 1991/1992. The area of the landslide is approximately 42,000 m(2) carrying an estimated volume of 500,000 m(3). This paper summarized the detailed geotechnical investigation carried out at the site to identify the causes and mechanism of failure, and recommends remedial measures. The slope failure resulted from two major causes: the presence of lateral failure planes within the colluvium aligned in a direction that promotes failure, and the lack of adequate drainage within the colluvium material. The following remedial alternatives are recommended: the material existing in the base of the embankment should be excavated and replaced with properly compacted material incorporating a suitable drainage system, and the road should be realigned with the slopes founded on rock and cut at a safe angle.