On the land reclamation of hills, the main engineering works are the cutting and banking of sloping land. In the work of banking in land reclamation, the compaction work on the soils is not sufficient as compared with that of the road embankments. Moreover, the slope of the bankings is ordinarily steeper than that of road embankments in order to expand the agricultural land. From this reason, sliding failure of slopes of embankments occure frequently after the construction.
In this paper, it is shown that the causes of sliding failure of a banking of cohesive soil of Masuda land reclamation are the rise of groundwater level and the decrease of shearing strength by water adsorption. The drainage works of groundwater are suitable for stabilization of the slope.