부산항 신항 연약지반의 장기 침하 특성 분석 및 GeoBIM 적용 연구 = Analysis of Long-Term Settlement Characteristics of Soft Ground and a Study on the Application of GeoBIM at the Busan New Port

다국어 초록 (Multilingual Abstract)

This paper aims to investigate the characteristics of the reclaimed soil around the Busan New Port through a literature review and to identify the limitations of the soil improvement methods applied to date. Furthermore, based on post-construction borehole logs from the first phase of the Busan New Port West Container Terminal project, we estimated the secondary consolidation index and compared it with the actual consolidation settlement observed at the Ungdong Hinterland Complex. This analysis confirmed that relying solely on design data to predict long-term settlement has significant limitations. Therefore, to clearly understand the influence of the secondary compression index, long-term settlement measurement data from Pier 5 of the Busan New Port was applied to a settlement prediction method. Actual ground information was obtained, and the EOP was calculated from the settlement curve to determine the secondary consolidation settlement. The results of this study are as follows. （1） Although port construction has expanded and the depth of the clay subgrade has increased, creating conditions conducive to long-term settlement, an analysis of the geotechnical data from the geotechnical report following the completion of Phase 1 of the Busan New Port West Container Terminal construction revealed that the estimated average secondary consolidation index was 0.00423 and the estimated average secondary consolidation settlement was 0.1212 m, figures close to ideal values. （2） In the report analyzing the causes of settlement in the Ungdong Hinterland Complex, the secondary consolidation settlement over a 30-year period was estimated based on geotechnical data from borehole logs to be 0.226–0.664 m, showing a difference of approximately 2 to 6 times compared to the consolidation settlement estimated in the previous design. （3） The range of long-term settlement over 14 years at 100 points along the road section within Pier 5 of the New Busan Port was 0.25–0.5 m. When using the hyperbolic method and the Asaoka method—two settlement prediction methods—to predict settlement over 1,000 days, 2,500 days, 4,000 days of measurement data to predict settlement over 5,000 days. While predictions were somewhat possible using the 4,000-day data, their utility was very low. This phenomenon occurred despite having sufficient settlement measurement data; the observed settlement was greater than that of previous data and did not converge, which is evidence that secondary consolidation is much greater than predicted during the design phase. （4） Assuming that high organic matter content was the cause of this settlement, dredged soil samples were collected and laboratory tests were conducted, confirming that the organic matter content of the dredged soil samples ranged from approximately 5.7% to 9.12%. To determine a meaningful secondary compression index based on organic matter, experiments were conducted with organic matter content ranging from 0% to 24% in 4% increments; the results showed that the secondary compression index ranged from 0.0057 to 0.018. （5） In addition, by obtaining borehole log data from locations where actual settlement was measured to verify the thickness of the clay layer, and by calculating the EOP from the settlement graph to analyze the secondary compression index and secondary consolidation settlement, it was found that it takes approximately 4 months to reach EOP, with the secondary consolidation index ranging from 0.0149 to 0.0273 and the secondary consolidation settlement ranging from 0.169 to 0.282 m. Ultimately, settlement management currently managed individually by port operators is unsystematic and unintegrated, making it difficult to address current settlement issues. To construct a stable Jinhae New Port with the goal of becoming a smart port, it is necessary to incorporate secondary consolidation settlement into design parameters and simultaneously establish a settlement measurement system operated by public institutions over the very long term, utilizing GeoBIM from the construction planning stage through the maintenance stage. Therefore, recognizing the importance of data and to establish a long-term system, the reliability of the secondary consolidation parameterization process must be enhanced by having the government or public institutions, rather than the private sector, take full responsibility for measurement management and transform the data into big data.

목차 (Table of Contents)

• 제1장 서 론 1
• 1.1 연구 배경 및 필요성 1
• 1.1.1 부산항 신항 건설 현황 및 지반침하 사례 1
• 1.1.2 2차 압밀침하 분석의 필요성 3
• 1.2 연구 내용 및 목적 5
• 1.2.1 침하사례 및 계측자료로부터 2차 압밀침하량 분석 5
• 1.2.2 2차 압축지수의 설계인자 적용 6
• 제2장 진해신항 주변 매립토 특성 및 적용된 지반개량공법 8
• 2.1 낙동강 하구 유입 퇴적물 특성 8
• 2.1.1 낙동강 하구 주변 점토지반 특성 8
• 2.1.2 부산항 신항 및 진해신항의 준설매립 특성 14
• 2.2 부산항 신항 및 진해신항 매립지 지반개량공법 16
• 2.2.1 PBD(PVD) 17
• 2.2.2 SCP, GCP 공법 등 19
• 2.2.3 현 지반개량공법의 한계 21
• 제3장 연약지반개량 설계 및 실제 침하 발생 현황 23
• 3.1 연약지반개량 설계 현황 23
• 3.1.1 침하 발생 주요 원인 및 해석방법 23
• 3.1.2 연약지반 판정기준 조사 26
• 3.2 연약지반 침하 발생 사례 30
• 3.2.1 부산항 신항 서컨 1단계 실시설계 압축지수 분석 30
• 3.2.2 웅동 항만배후단지 장기침하 사례 33
• 3.3 연약지반개량 설계시 추가 고려 요소 38
• 제4장 부산항 신항 준공 후 장기침하 실측자료 분석 및 원인 추정 · 42
• 4.1 부산항 신항 장기침하 실측자료 분석 42
• 4.1.1 계측 방법 및 침하 현황 42
• 4.1.2 시나리오별 침하예측 분석 46
• 4.2 유기물에 의한 2차 압밀침하량 실내실험 61
• 4.2.1 실내실험 방법 61
• 4.2.2 유기물 함량별 압밀 특성분석 결과 64
• 4.3 장기계측자료 기반 2차 압밀침하량 추정 72
• 4.4 소결론 80
• 제5장 침하 mapping 및 신속 대응을 위한 GeoBIM 적용 81
• 5.1 부산항 신항 및 진해신항 지반특성 BIM 모델링 81
• 5.1.1 기존 지반조사의 활용 한계 및 GeoBIM 81
• 5.1.2 시추주상도 지반정보를 가시화한 BIM 모델 84
• 5.2 GeoBIM의 지반정보로부터 신속한 침하분석 적용 93
• 5.2.1 GeoBIM에서 지반정보 입력 및 활용성 93
• 5.2.2 GeoBIM에서 지반정보, 계측정보로부터 침하영향 분석 95
• 5.3 소결론 103
• 제6장 요약 및 결론 105
• 참고 문헌 109