Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Constructing Database and Probabilistic Analysis for Ultimate Bearing Capacity of Aggregate Pier

쇄석다짐말뚝의 극한지지력 데이터베이스 구축 및 통계학적 분석

  • Park, Joon-Mo (Dept. of Civil and Environmental Engineering, Dongguk Univ.) ;
  • Kim, Bum-Joo (Dept. of Civil and Environmental Engineering, Dongguk Univ.) ;
  • Jang, Yeon-Soo (Dept. of Civil and Environmental Engineering, Dongguk Univ.)
  • 박준모 (동국대학교 공과대학 건설환경공학과) ;
  • 김범주 (동국대학교 공과대학 건설환경공학과) ;
  • 장연수 (동국대학교 공과대학 건설환경공학과)
  • Received : 2014.06.12
  • Accepted : 2014.08.13
  • Published : 2014.08.31
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Abstract

In load and resistance factor design (LRFD) method, resistance factors are typically calibrated using resistance bias factors obtained from either only the data within ${\pm}2{\sigma}$ or the data except the tail values of an assumed probability distribution to increase the reliability of the database. However, the data selection approach has a shortcoming that any low-quality data inadvertently included in the database may not be removed. In this study, a data quality evaluation method, developed based on the quality of static load test results, the engineering characteristics of in-situ soil, and the dimension of aggregate piers, is proposed for use in constructing database. For the evaluation of the method, a total 65 static load test results collected from various literatures, including static load test reports, were analyzed. Depending on the quality of the database, the comparison between bias factors, coefficients of variation, and resistance factors showed that uncertainty in estimating bias factors can be reduced by using the proposed data quality evaluation method when constructing database.

국내 외 하중저항계수설계법의 저항계수 보정 시 수집된 데이터베이스의 신뢰성을 향상시키기 위하여 저항편향계수 산정 단계에서 저항편향치의 ${\pm}2{\sigma}$ 범위의 데이터만을 선택하거나 가정된 확률분포 검정을 만족하도록 꼬리(tail)부분의 데이터를 제거하는 방법을 적용하고 있다. 그러나 이들 방법에서는 데이터베이스 내에 우연히 포함된 저품질의 데이터를 확인할 수 없는 단점이 발견되었다. 본 연구에서는 정재하시험의 품질, 원지반의 공학적 특성, 쇄석다짐말뚝의 제원 등의 품질기준을 이용하여 데이터베이스 구축 단계에서 수행할 수 있는 품질평가법을 제안하였으며, 국내 외 문헌 및 정재하시험 보고서로부터 65개소의 정재하시험 데이터를 수집하여 데이터베이스의 구축 및 품질평가를 수행하였다. 데이터베이스의 품질 평가 상태에 따른 저항편향계수와 변동계수, 저항계수를 비교한 결과, 기존의 데이터베이스 처리과정과 품질평가법을 병행할 경우에 저항편향계수의 불확실성이 감소되며, 신뢰도 높은 LRFD 저항계수 보정에 효과적인 것으로 판단된다.

Keywords

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