KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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The Reinforcing Effect of Blade Attached Pile to Support Submerged Breakwater

보강날개로 보강된 수중잠제 지지말뚝의 보강효과 분석

  • 정상섬 (연세대학교 토목환경공학과) ;
  • 홍문현 (연세대학교 토목환경공학과) ;
  • 고준영 (연세대학교 토목환경공학과)
  • Received : 2015.04.18
  • Accepted : 2015.07.02
  • Published : 2015.08.01
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Abstract

The use of pile reinforcement is considered as one of the most promising techniques for improving load carrying capacity of piles in offshore area. In this study, to consider the horizontal and uplift bearing capacity of submerged breakwater bearing pile, exclusive analysis on load-transfer behaviour of pile was conducted. First of all, check the reinforcing effect from the three-dimensional finite element method, and estimate load transfer curve (ground reaction force). Based on these results, the reinforcing effect was quantified by estimating the coefficients of horizontal and uplift reinforcement of reinforced piles. Load transfer function with consideration of the reinforcing effect was proposed from estimated coefficients. A comparison of the analysis using the proposed load transfer function with three-dimensional finite element analysis has resulted that the proposed load transfer function is displaying good accuracy of predicting behavior of the load transfer between the pile and soil reinforcement. Interpretation of the submerged structure by applying a load transfer function considering the reinforcing effect, has shown that the reinforced pile's shear, bending moment and displacement are less than that of non-reinforced piles, while the subgrade reaction modulus arises greater. Thus, it is expected to be relatively cost effective in terms of design.

본 연구에서는 보강날개로 보강된 수중잠제 지지말뚝의 보강효과를 분석하기 위하여 하중전이거동을 분석하였다. 먼저 3차원 유한요소해석을 통해 말뚝의 변위 및 하중전이곡선(지반반력) 결과로부터 보강효과를 확인하고, 하중전이곡선에서 극한저항력 비율로 보강말뚝의 수평 및 인발하중에 대한 보강계수를 산정함으로써 보강효과를 정량화 하였다. 산정된 보강계수를 쌍곡선 하중전이함수의 극한저항력 $p_u$와 $t_{max}$에 곱해서 보정상수(fitting parameter)로 적용하여 보강효과를 고려한 하중전이함수를 제안하였다. 제안된 하중전이함수가 수치해석 결과를 잘 반영하고 있는지 확인하기 위해 3차원 유한요소해석을 비교하여 보강말뚝의 하중전이거동을 분석하였다. 제안된 하중전이함수를 하중전이법 해석에 적용하여, 실제 수중잠제를 해석한 결과 보강말뚝의 전단력, 휨 모멘트, 변위가 무보강말뚝보다 작게 발생하고, 지반반력은 더 크게 발생하여 비교적 경제적인 설계가 가능할 것으로 판단된다.

Keywords

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