Steel pipe pile with spiral blades, composite pile, and method for constructing composite pile

摘要

There is disclosed a steel pipe pile with spiral blades which is capable of effectively improving comparatively soft ground in which a clay layer and the like are present at deep positions of several ten meters beneath the surface of the ground. A steel pipe pile 1 with spiral blades comprises a steel pipe pile main body 10 and one or more spiral blades 20 attached to the steel pipe pile main body 10, and a diameter D of the spiral blade 20 is set to three times or more as large as a diameter d of the steel pipe pile main body 10.