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 w as the result of foundation instability during the exceptionally heavy rainfall season of 1991/1992. The area of the landslide is approximat ely 42,000 m(2) carrying an estimated volume of 500,000 m(3). This pap er summarized the detailed geotechnical investigation carried out at t he site to identify the causes and mechanism of failure, and recommend s remedial measures. The slope failure resulted from two major causes: the presence of lateral failure planes within the colluvium aligned i n a direction that promotes failure, and the lack of adequate drainage within the colluvium material. The following remedial alternatives ar e recommended: the material existing in the base of the embankment sho uld be excavated and replaced with properly compacted material incorpo rating a suitable drainage system, and the road should be realigned wi th the slopes founded on rock and cut at a safe angle.