Abstract
It is sometimes inevitable in recent years to construct an earthfill dam even on a soft soil layers. In such cases some special problems associated with soft soil condition will become of more importance than the case of stiff stable foundation conditions. The most significant problem among that was subsidence and stability of slopes. From the conventional stability analyses by means of circular slip surface, it is found that the critical slip circle goes through the foundation ground and some countermeasure will be needed for designing cross section of the dam. Therefore gravel compaction pile was adopted to increase the shear strength of soils and the safety factor of embankment. Some geotechnical consideration were made on the design of gravel compaction pile and finally the safety factor of the dam including the foundation ground could raise to greater than 1.2.
