This study proposes an advanced type of a micropile system. The proposed micropile system consists of perfobond ribs installed steel rod to improve shear capacity between the thread and the grout, and partially expanded drill holes to increase resistance capacity between the grout and the ground. This study contains experimental evaluations on the proposed micropile system to verify the load-carrying capacity of shear key created by the partially expanded drill hole. Through on-site pullout tests, it was found that load-carrying capacity increased significantly in the proposed micropile system, due to the shear keys created by the partially expanded drill hole.

• 정치영(연세대학교 토목환경공학과 박사과정, 공학석사) | Jung, Chi Young
• 이현민(연세대학교 토목환경공학과 석사과정, 공학사) | Lee, Hyun Min
• 원성환(연세대학교 토목환경공학과 석사과정, 공학사) | Won, Seong Hwan
• 김상효(연세대학교 사회환경시스템공학부 교수, 공학박사) | Kim, Sang Hyo