연약한 사질토와 점성토가 교호로 형성된 지반에 적합한 심층혼합처리공법(DCM)의 최적 배합비 연구 : DCM 최적배합비 연구

다국어 초록 (Multilingual Abstract)

This research investigates the geotechnical properties of soft ground characterized by alternating layers of loose sandy and cohesive soils, utilizing results from field borehole investigations, laboratory analyses, and in-situ testing. Based on the comprehensive data collected, suitable design parameters for the soil were established. The study also compares various ground improvement methods, taking into account adjacent structures, environmental considerations, and site development needs, to recommend a practical and economical solution. Special attention was given to the application of the Deep Cement Mixing (DCM) technique to control adjacent settlement in proximity to sensitive facilities such as the Busan–Masan double-track railway. The main objective of the study is to derive the optimal mixing ratio for DCM customized to these ground conditions. The DCM design mixing ratio was determined based on construction cases near the Busan Eco Delta project, and the optimal mixing ratio was finally established through a series of laboratory mixing tests, hydraulic sampler applications, and verification borings carried out in Section 3 of Phase 3 of the Busan Eco Delta development project. While numerous case studies exist for marine DCM applications, there are relatively few large-scale land-based DCM projects or research cases. Therefore, this case study aims to establish a construction guideline for effectively controlling the impact of settlement on adjacent structures in deltaic soft ground, where sandy and cohesive soils alternate, such as the lower Nakdong River estuary.
Keywords : Land-based DCM, Soft Ground, Alternating Layers, Adjacent Settlementt, DCM Optimal Mixing Ratio, Ground Improvement

목차 (Table of Contents)

• List of Tables ⅲ
• List of figures ⅳ
• Abstract ⅵ
• 1. 서론 1
• 1.1 연구의 배경 1
• 1.2 연구의 목적 4
• 2. 기존 연구 6
• 2.1 DCM공법의개요 6
• 2.1.1 공법의 정의 6
• 2.1.2 시공원리 6
• 2.1.3 장단점 7
• 2.2 심층혼합처리(Deep Cement Mixing) 공법의 연구 고찰 7
• 2.2.1 국외 활동 현황 7
• 2.2.2 국내활동 현황 9
• 2.3 배합비와 강도 발현 특성 11
• 2.3.1 실내배합강도 산정 11
• 2.3.2 물-시멘트비(W/C) 13
• 2.4 기존적용사례(부산 강서구 인근) 15
• 3. 실내배합시험 19
• 3.1 시험 목적 및 필요성 19
• 3.2 시험절차 19
• 3.3 배합조건 20
• 3.4 시험결과 22
• 3.5 시험결과 정리 25
• 4. 현장 시험시공 27
• 4.1 지층특성 (시공지역) 27
• 4.1.1 사전 조사 결과 27
• 4.1.2 인근지역 지반 특성 연구 (연약지반 개량전후) 32
• 4.2 시험시공 목적 35
• 4.3 시험배합 조건 35
• 4.4 시험위치 및 지반조건 36
• 4.5. 시험시공 절차 39
• 4.6. 시험시공 결과 43
• 4.6.1 일반사항 43
• 4.6.2 현장 시료채취 결과 43
• 4.6.3 확인보링 결과 46
• 4.6.4 종합정리 52
• 5. 결과 및 고찰 54
• 참고문헌 55
• 국문초록 58