Abstract
The amount of material upheaved owing to the installation of a granular compaction pile (GCP) in the seabed was analyzed by a field execution. The amount of material upheaved was predicted by existing equations, proposed by the Korea Construction New-Technology Association (KCNET; 2003) and Shiomi and Kawamoto (1986), and compared with the amount measured by bathymetry in the field. As a result, the upheaval heights were found to show a clear increase with increasing replacement ratio. The measured amount was larger than the amount predicted by the equations, but the amount predicted from the equation proposed by KCNET (2003) was relatively close to the measured amount. The upheaval heights were found to be more sensitive to the replacement ratio than the installation depth. The increasing trends of the upheaval heights with the installation depth as predicted by the equation of KCNET (2003) were in agreement with the measured trends at a replacement ratio of 25%. As a result of comparing the coefficients of upheaval by the equations, the coefficients of upheaval determined by the equation of KCNET (2003) were larger than those determined by the equation proposed by Shiomi and Kawamoto (1986), which were relatively close to the measured trends. Specifically, the difference between results obtained by both these equations was large when the replacement ratio was relatively low.
해상에서 쇄석다짐말뚝(GCP) 타설로 발생하는 해저지반의 융기량을 현장 시공사례를 통하여 분석하였다. 기존의 경험식들에 의해 융기량을 추정하고 시공단계에서 수심측량을 통하여 얻은 실제 융기량과 비교 분석하였다. 실측 융기고와 경험식에 의한 융기고를 분석한 결과, 치환율에 따라 융기고가 뚜렷이 증가하였고 실측치가 경험식에 의한 추정치에 비하여 컸으나 비교적 국내 건설신기술품셈(한국건설신기술협회, 2003)에 제시된 경험적 방법이 실측치에 근사하였다. 융기고는 개량심도 보다는 치환율에 보다 민감함을 알 수 있었고, 건설신기술품셈(2003)에서 제시한 방법의 경우 치환율 25%에서 개량심도에 따른 융기고 증가추세가 실측추세와 매우 잘 일치하였다. 경험식에 따른 융기량을 융기율로 비교한 결과, 건설신기술품셈(2003)의 제안식으로써 산정한 융기율이 Shiomi and Kawamoto(1986)의 제안식에 의한 값보다 크게 나타나 비교적 실측치와 근접하는 경향을 보이고 특히, 치환율이 작은 경우에 두 식 사이의 차이는 심한 것으로 나타났다.
