흙막이가시설 설계사례의 역해석 기반 입력변수 영향 분석 = Design Cases of Temporary Earth Retaining Structures and Analysis of Input Variable Influence Based on Inverse Analysis

다국어 초록 (Multilingual Abstract)

Design Cases of Temporary Earth Retaining Structures and Analysis of Input Variable Influence Based on Inverse Analysis Kim, Hoyeon Advisor : Prof. Kim, Daehyeon, Ph. D. Department of Civil Engineering Graduate School of Chosun University In excavation work, discrepancies frequently occur between the ground parameters applied during the design phase and the behavior measured during actual construction. Accordingly, this study was conducted to analyze the difference between the ground parameters in the design phase and the actual measured behavior at the actual excavation site, and to provide a reference improvement direction when calculating the initial ground parameters and establishing the design and measurement plan for the temporary structure through reverse analysis and correction requirement analysis based on the measurement data. Based on the results of the geotechnical investigation at the target site, laboratory and field test data, design documents, and construction records, the soil parameters at the design stage and the original design analysis conditions were organized. Subsequently, inclinometer, surface settlement, groundwater level, and member stress measurement data for each excavation stage were collected and organized. Representative measurement cross-sections and excavation stages were selected to analyze the actual behavioral characteristics. The back analysis was performed by setting wall horizontal displacement as the principal response and surface settlement, groundwater level, and member stress as auxiliary verification responses. The main correction variables consisted of elastic modulus, cohesion, internal friction angle, and unit weight. Furthermore, to compare the correction results derived from multiple back analysis models, Back Analysis Variation Index （BI） was defined by normalizing the correction amount for each variable by the search range, thereby quantitatively evaluating the relative level of modification required for each variable. The study results showed that while the initial design analysis demonstrated a certain level of validity regarding the overall increasing trend of excavation behavior and structural stability, differences existed when compared to actual measurement results regarding the magnitude and location of maximum horizontal displacement of the wall, the distribution of surface settlement, and some structural responses. Inverse analysis revealed that the elastic modulus of the upper and middle layers was the variable with the greatest influence on the reproduction of actual behavior; furthermore, the BI analysis also showed the highest value for the elastic modulus, confirming it as a key variable requiring the largest correction relative to the initial design values. Cohesion and internal friction angle played important auxiliary roles depending on the soil type and response characteristics, while unit weight indicated a relatively small correction requirement.

목차 (Table of Contents)

• 제 1 장 서 론 1
• 1.1 연구배경 및 목적 1
• 1.2 국내·외 연구동향 3
• 1.3 연구내용 및 방법 5
• 제 2 장 이론적 배경 8
• 2.1 흙막이 가시설의 거동 특성 8
• 2.2 지반정수 선정 및 가시설 설계 해석 방법 10
• 2.3 계측자료와 역해석의 활용 13
• 2.4 설계지반정수 선정 개요 및 문헌자료 15
• 2.4.1 설계지반정수 선정 개요 15
• 2.4.2 투수계수 문헌자료 16
• 2.4.3 설계지반정수 결정을 위한 문헌자료 19
• 2.4.4 경험식에 의한 강도정수 결정 21
• 2.5 수치해석에 의한 지반안전성 검토 23
• 2.5.1 검토기준 23
• 2.5.2 흙막이 구조물 허용변위 및 침하 기준 25
• 2.5.3 설계하중 28
• 2.6 지반정수 및 지반탄성계수 30
• 2.6.1 탄성계수 및 변형계수 31
• 2.6.2 내부마찰각 32
• 2.6.3 점착력 33
• 2.6.4 단위중량 34
• 2.7 역해석의 방법론 35
• 제 3 장 대상현장및지반굴착설계 37
• 3.1 대상 현장 개요 및 지반조건 37
• 3.2 지반조사 및 실내·현장시험 결과 39
• 3.3 설계단계 지반정수 선정 절차와 근거 42
• 3.4 가시설 형식 및 대표단면 47
• 3.5 해석모델 및 시공단계 설정 50
• 3.6 설계단계 해석 결과 56
• 3.6.1 수치해석 결과 분석 A-A‘ 단면 56
• 3.6.2 수치해석 결과 분석 B-B‘ 단면 59
• 3.6.3 수치해석 결과 분석 E-E‘ 단면 64
• 제 4 장 계측 결과 및 분석 68
• 4.1 계측계획 및 위치선정 68
• 4.2 굴착단계 별 지중변위 거동 70
• 4.3 지표침하 및 부재응력 계측결과 74
• 4.3.1 지표침하 계측분석 74
• 4.3.2 하중계 계측분석 76
• 4.4 당초 설계 해석결과와 계측결과 비교 및 원인고찰 78
• 제 5 장 역해석 기반 지반정수 추정 80
• 5.1 역해석 수행 목적 80
• 5.2 보정 대상 변수 및 범위 82
• 5.3 단계별 역해석 수행 절차 84
• 5.4 보정 결과 및 보정 전후 해석 비교 86
• 제 6 장 주요 변수의 보정지수 분석 및 영향검토 101
• 6.1 분석 목적 및 변동지수 101
• 6.2 주요 지반변수의 변동지수 경향 비교 103
• 6.3 변동지수분석에 따른 지반정수 선정 고찰 110
• 6.4 연구의 의의 및 한계 112
• 제 7 장 결 론 113
• 참고문헌 115