Locations of confined waste disposal facilities in coastal area generally have a great potential in land use for logistics, factories, commercial facilities, leisure facilities, and so on; however, most of them have not effectively used, because leakage of contaminated groundwater is concerned when piles are driven through the soft clay layer which takes a role as hydraulic barrier. In this study, applicability of piled foundations to the confined waste disposal facilities was examined through a series of field tests to demonstrate the performance of impermeability around piles in the clay layer (hydraulic barrier) when the piles are driven under a high level of construction management and quality control. The site conducted the field tests was reclaimed since the late 1970s with non-incineration wastes such as raw trash, plastic, vinyl, metal, concrete fragments. From the field tests, the following conclusions were obtained. When a steel pipe pile is driven by casing method (using hammer grab) or inner excavation method (using both auger and hammer grab), the tip of the pile didn’t bring a waste into the clay layer and high-performance impermeability around the pile was confirmed. Note here that a hammer grab was necessary to remove the wastes/soils, particularly　concrete fragments, from inside of the casing/pile. When a steel pipe pile is driven by hydraulic hammer, the tip of the pile brought a large amount of wastes into the clay layer, even though a hammer grab was used to remove the wastes from inside of the pile, resulting in low-performance impermeability around the pile. When a PHC pile, which has a thick pipe wall and a small inner diameter, was driven by inner excavation method (using auger), pile driving was terminated because inside of the pile was completely clogged by fine soils clinging to the auger.