These composite piles are made from steel pipe piles with protrusions on the outer surface and hardened bodies (soil cement columns). The piles possess high vertical bearing capacity and are capable of supporting foundation structures with a small number of piles. As a result, the piles contribute to reduced construction costs.

Evaluation is performed for large tip bearing force at the bottom of the soil cement column, and for frictional force and horizontal support force for the circumferential surface. In addition, it is a hybrid pile with high-bearing capacity which exhibits high toughness against bending due to the use of steel pipe.

Since the in-situ soil is effectively used to form a hardened body, this construction method produces less soil than conventional construction methods that are based on excavation and replacement. Since the soil generated from construction is cement-stabilized soil, it can be recycled for use as leveling soil and backfill soil at the construction site.

The construction efficiency is higher than conventional construction methods that are based on excavation and replacement, thus contributing to a shortened construction period. We will select the appropriate construction method according to the site conditions and construction environment, and then propose the advantages of adopting the method.

A one-process construction method in which rotary embedding is simultaneously performed for steel pipe piles at the same time as forming a hardened body. Since the construction cycle is shorter than the post-lay burying method, the construction period is shortened in many cases. These characteristics are highly applicable to large-scale construction.
The stabilizer installed on the rod maintains a constant distance between the rod and the steel pipe pile, so high vertical accuracy is maintained even when constructing long piles.

A two-process construction method in which the steel pipe is buried after the hardened body is formed. Depending on the details of the pile and the soil condition, the construction machine can be downsized. This makes the method applicable to construction in a narrow environment or construction under height limits.