지보재 파괴를 고려한 터널의 안전율 평가에 관한 연구 = (The) Evaluation for Safety Factors of Tunnels Considering the Failure of Supports

다국어 초록 (Multilingual Abstract)

The safety factor of a tunnel considering the failure of supports is important because the failure of supports might cause the collapse of the tunnel.
In the previous studies, shotcrete was modelled as beam elements and the failure of the shotcrete was checked according to the allowable working stress concept.
In this study, shotcrete was modelled by both beam elements and continuum (elasto-plastic) elements. Safety factors of tunnels were estimated by two dimensional numerical analysis with varying rock mass class, coefficient of lateral pressure, thickness of shotcrete, rock bolt reinforcement and excavation method. Also the study suggested not only a proper amount of supports but also modelling method.
Also three dimensional analyses were performed to suggest a proper advanced rate, in which the shotcrete was modelled only by continuum elements.
As a results, continuum elements gives more stable results then beam elements in terms of displacement and stress. Therefore it was concluded that shotcrete could be modelled as continuum elements to estimate safety factor of tunnels better.
It was also concluded that the safety factor of a tunnel obtained with continuum elements reduced as the rock mass condition became weaker but almost same safety factor was obtained with two different excavation methods.
In addition, it was shown that the safety factor increased as the thickness of shotcrete increased and decreased as the advanced rate increased as expected.

목차 (Table of Contents)

• 목차 = ⅰ
• 표목차 = ⅲ
• 그림목차 = ⅳ
• 제1장 서론 = 1
• 1.1 연구 배경 및 목적 = 1
• 1.2 기존 연구에 대한고찰 = 3
• 1.3 연구내용 및 방법 = 5
• 제2장 이론적 배경 및 해석 방법 = 7
• 2.1 터널의 안전율 = 7
• 2.2 전단강도 감소기법에 의한 안전율 계산 = 8
• 2.2.1 전단강도 감소기법 = 8
• 2.2.2 전단강도 감소기법에 의한 터널의 안전율 계산 Routine = 10
• 2.3 수치 모델링 = 13
• 2.3.1 2차원 해석 및 3차원 해석에 사용된 지반의 모델링 = 13
• 2.3.2 지보재 모델링 = 16
• 2.3.3 굴착모델링 = 19
• 2.3.4 지반 및 지보재의 물성 = 19
• 2.3.5 2차원 해석시 하중 분배율 = 24
• 제3장 2차원 해석 결과 = 27
• 3.1 2차원 해석에 의한 안전율 = 27
• 3.2 측압 및 숏크리트 두께가 안전율에 미치는 영향 = 29
• 3.2.1 암반등급별 안전율 = 29
• 3.2.2 록볼트 보강이 안전율에 미치는 영향 = 41
• 3.2.3 보(beam)요소와 연속체(탄성체)요소의 내공변위 비교 = 47
• 제4장 3차원 해석결과 = 52
• 4.1 3차원 해석에 의한 터널의 안전율 = 52
• 4.2 2차원 해석과 3차원 해석의 내공변위비교 = 56
• 4.3 굴진장에 따른 터널의 안전율 = 60
• 제5장 결론 = 71
• 참고문헌 = 74
• ABSTRACT = 77