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Lateral Bearing Capacity of Triaxial Micropile by Installaton Condition

설치조건에 따른 삼축 마이크로파일(TMP)의 수평지지력

  • Received : 2021.04.11
  • Accepted : 2021.04.20
  • Published : 2021.05.01

Abstract

Micropile refers to a small-diameter cast-in-place pile of less than 300 mm. In general, even though it is a small-diameter pile, it is known that the resistance of the pile to the vertical force is large, while the resistance to the lateral load is insufficient. Among several micropile methods, a triaxial micropile (TMP) was recently developed for the purpose of increasing the lateral bearing capacity (seismic resistance). A triaxial micropile has the advantage of being able to effectively resist lateral loads because three micropiles installed inclined on each axis resist lateral load. As a result of the study, In the short pile (L/d < 60), the lateral bearing capacity increased due to the increase in the pile length ratio, but in the long pile (L/d ≥ 60), the increase in the bearing capacity was insignificant. The lateral bearing capacity increased as the triaxial micropile installation angle (θ) increased, but the increase in the lateral bearing capacity was clearly decreased when it exceeded 35°. The increase in the lateral bearing capacity was greater with the increase of the micropile installation angle (θ) in the long pile than the short pile.

마이크로파일은 300mm 이하인 소구경 현장타설말뚝을 말하며, 일반적으로 소구경 파일임에도 연직력에 대한 파일의 저항력이 큰 반면, 수평하중에 대한 저항성은 미비한 것으로 알려져 있다. 여러 마이크로파일 공법들 중 최근 수평지지력(내진저항력)의 증가를 위한 목적으로 개발된 삼축 마이크로파일(Triaxial micropile, TMP)이 개발되었다. 삼축 마이크로파일은 각축에 경사지게 설치된 3개의 마이크로파일이 수평하중에 저항하므로 좀 더 효과적으로 수평하중에 저항할 수 있는 장점이 있다. 본 연구에서는 파일길이 및 설치각도를 달리 설치했을 경우 삼축 마이크로파일에 대한 수평지지력을 평가하고자 3차원 수치해석을 수행하였다. 연구결과, 짧은 파일(L/d < 60)에서 파일길이비 증가에 따른 수평지지력 증가가 발생하였으나, 긴 파일(L/d ≥ 60)에서는 지지력 증가가 미미했다. 마이크로파일 설치각(θ)이 증가함에 따라 수평지지력이 증가하였으나 35° 초과 시 지지력 증가가 급격히 저하되었고, 짧은 파일보다 긴 파일에서 마이크로파일 설치각(θ)의 증가에 따른 수평지지력 상승이 컸다.

Keywords

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