To form sufficient bearing power by integrally connecting a sufficiently long base section steel pipe and a tip steel pipe larger in diameter than it via a connecting member.
A sufficiently long base section steel pipe 2 and a tip steel pipe 3 larger in diameter than the steel pipe 2 are connected by welding via a connecting member 4 to form a steel pipe pile 1. An air vent hole 7 is provided on the connecting member 4 so that no air is accumulated below the connecting member 4, thus the strength degradation of a foot protection section is prevented. At the time of execution, a root protection liquid is injected into an excavation hole excavated to the bearing ground and is mixed with the sediment of the bearing ground, a pile fixing liquid is injected, then a pile 1 is inserted into the excavation hole to fix the steel pipe 3 to the root protection section. A casting constituted of a tip large-diameter section, a connection section, and a neck section may be connected to the base section steel pipe 2 via the neck section to increase thickness instead, and the tip large-diameter section and the connection section are smoothly connected to prevent stress concentration. The root protection section can be formed with good accuracy, and large tip bearing power can be formed with the large-diameter section.
KOYAMA SEIICHI
YANAGIMOTO YASUTOMO
IIDA HISAO
TANAKA HIROMASA
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