ABSTRACT
Currently, the circulation method and the reverse circulation method are applied to the construction of the cast-in-place piles under the overhead restrictions and other site access restrictions. BH method and TBH method are the representative methods of the circulation and the reverse circulation method, respectively. In the circulation method, from its excavation mechanism, the construction machinery can be downsized. However, mud cakes can be easily formed in the excavation holes, and slime can settle around the pile end because of the circulation of the high-density stabilizing slurry with flowing excavated materials in the excavation hole. Therefore, it is considered that the piles constructed by this method are not reliable and of low quality from the point of view of the bearing capacity, when it is applied to permanent structures.
