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석션보드드레인 공법에서 하드닝 존을 고려한 압밀 침하 해석

Title
석션보드드레인 공법에서 하드닝 존을 고려한 압밀 침하 해석
Other Titles
Analysis of consolidation settlement considering hardening zone in suction board drain method
Author
김기년
Alternative Author(s)
Kim, Ki Nyun
Advisor(s)
김수삼
Issue Date
2008-08
Publisher
한양대학교
Degree
Doctor
Abstract
본 연구에서는 연약지반을 목적에 맞게 개선하기 위한 방법으로 성토하중 및 멤브레인 등이 필요치 않은 석션보드드레인(Suction Board Drain) 공법의 개량기간 및 적용 석션압에 따른 개량도를 파악하고 하드닝 존(Hardening Zone)의 범위 및 투수계수 감소비를 산정하기 위하여 일련의 실내 실험을 실시하였다. 또한 하드닝 존을 고려한 석션보드드레인 공법에 최적화된 Suction-CAIN 수치해석 프로그램을 개발하여 민감도 분석을 수행하고, 본 공법의 현장시험결과와 비교/분석하여 그 적용성을 검토하였다. 실내 실험 결과, 하드닝 존의 범위는 초기 투수성에 따라 산정할 수 있었으며, 투수계수 감소비(하드닝 존의 투수계수/초기투수계수)의 크기를 초기 시료 특성에 따라 구할 수 있었다. 개발된 Suction-CAIN 수치해석 프로그램의 경우, 실제 3차원적인 배수재 타설 효과를 고려한 해석이 가능하도록 Hird가 제안한 등가 투수계수의 개념을 적용하였으며, 실제 진공압 효율의 고려가 가능하도록 배수재를 별도의 Drainage Bar Element로 고려하여 수치해석 수행하였다. 개발된 해석 프로그램의 민감도 분석 결과, 유한요소의 형상 및 수치해석 단면상 배수재의 타설개수는 프로그램 해석 결과에 큰 영향을 미치지 않았고, 진공압과 하드닝존의 범위에 민감하게 반응함을 파악할 수 있었다. Suction-CAIN 프로그램의 적용성을 검토하기 위해 현장 시험 결과 및 기존프로그램 해석 결과와 비교/검토한 결과, 기존 프로그램이 실제 거동 보다 비교적 큰 변위 거동을 나타낸 반면, Suction-CAIN 프로그램 해석결과의 경우, 현장시험시공에서 계측된 결과와 연직변위, 수평변위, 진공압, 간극수압 거동에서 거의 유사한 결과가 나타났다. 이는 하드닝 존의 범위 및 투수계수감소비를 고려하여 비교적 현장조건과 유사하게 모사할 수 있었고, 배수재 길이에 따른 진공압 감소율을 고려할 수 있었기 때문에 나타난 결과이다.; The purpose of this study is to assess the degree of improvement per duration of improvement for Suction Board Drain method which does not require surcharge load and sealing sheet and to evaluate the impact of hardening zone in order to improve soft ground for its purposes. So, a series of laboratory column tests were constructed to estimate the range of the hardening zone and decreasing ratio of the permeability coefficient. Furthermore, a Suction-CAIN numerical analysis program was developed, which optimizes the Suction Board Drain method of construction that considers the hardening zone. Following this were sensitivity tests that were performed. Also comparison and analysis on the results obtained at the actual site experiment on this method of construction was examined with its applications. From laboratory tests, the range of the hardening zone estimated, according to the initial permeability coefficient. Also, the decreasing ratio of the permeability coefficient(hardening zone permeability coefficient/initial permeability coefficient) estimated, according to the initial permeability coefficient. However, the hardening zone was not developed in the sample with rather high initial permeability. In the case of the developed Suction-CAIN numerical analysis program, Hird's theory was applied to consider the effects on an actual 3-dimensional drain placement, which was an improvement from the 2-dimensional numerical analysis when executed, had dimensional delineation problems. Furthermore, numerical analysis was performed separately for the drainage bar element so that the actual efficiency of vacuum pressure was taken into account. According to the results of the sensitivity issues retrieved from the analysis program, formation of the finite element and number of drains placed regarding the interpretation of numerical analysis did not affect the analysis of the program. However, it reacted greatly to range of the hardening zone and vacuum pressure. In order to examine the Suction-CAIN program’s application potentials, comparison on commercial program(Sage Crisp) results and site experiment results were done. Commercial programs had a tendency to have greater displacements than the actual displacements. On the other hand, Suction-CAIN program had similar results to the actual construction site measurements, such as, settlement, horizontal displacement, vacuum pressure, pore water pressure. This result was given due to similar environmental factors that were copied from the in-situ site, such as the decreasing ratio of permeability coefficient and the range of the hardening zone. Even more, the consideration of the drain’s length had given a more precise measurement in regarding the decreasing ratio of vacuum pressure.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/146064http://hanyang.dcollection.net/common/orgView/200000409889
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > DEPARTMENT OF CIVIL ENGINEERING(토목공학과) > Theses (Ph.D.)
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