절리암반에서 근접사면 굴착 시 기존터널의 안정성 평가를 위한 근접도 연구
Study on the Proximity Diagram for Tunnel Stability Evaluation in Case of Adjacent Slope Excavation in Jointed Rock Masses
- 주제(키워드) 절리암반 , 근접사면 굴착 , 터널 근접도
- 발행기관 아주대학교
- 지도교수 이상덕
- 발행년도 2009
- 학위수여년월 2009. 8
- 학위명 박사
- 학과 및 전공 일반대학원 건설교통공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000010108
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
본 논문에서는 기존 터널에 근접하여 절리암반 사면을 굴착할 때에 응력해방과 암반 변위에 의해 터널이 변형됨에 따라 기존 터널의 안정성이 저하되는 것을 방지하기 위한 굴착 깊이에 대한 터널 근접도를 연구하였다. 특히, 터널과 동일한 이격거리의 사면을 굴착할 때에 절리각도와 굴착사면 경사를 고려하여 터널의 안전성을 확보할 수 있는 한계 깊이를 구하였다. 이를 위하여 절리면 경사각은 0°, 30°, 60°, 90°로 변화시키고 각 절리면 경사각에 대해 굴착사면 경사가 60°, 75°, 90°인 경우를 2차원 대형모형시험과 수치해석을 통하여 분석하였다. 대형모형시험은 3.1m(폭), 3.1m(높이), 0.5m(길이) 크기의 시험장치에서 콘크리트 블록을 사용하여 시험지반을 조성하여 수행하였다. 터널에서 사면까지는 터널 직경(D)만큼 이격시켰으며, 모형터널은 1/20의 상사율을 적용하여 두께 6㎜, 직경 0.6m로 제작하였다. 수치해석은 개별요소법 프로그램인 UDEC을 사용하여 수행하였다. 대형모형시험 결과와 수치해석 결과를 비교분석하여 동일한 절리면 경사각에서도 굴착사면 경사와 굴착 깊이에 따라 터널 내공변위와 터널의 부재력이 다르게 발생하며, 터널 안전에 영향을 미치는 사면의 굴착 깊이는 굴착사면 경사가 급할수록 얕아진다는 것을 확인하였다. 굴착사면 경사가 절리면 마찰각보다 큰 경우에는 사면굴착 시 사면 붕괴가 발생하지만, 사면을 절리면 경사각과 동일한 경사로 굴착을 하면 사면붕괴를 방지할 수 있으며, 터널의 안정성을 높일 수 있을 뿐만 아니라 터널과의 이격거리도 감소시킬 수 있다는 것을 확인하였다. 이상의 연구를 통해서 절리암반 내 기존터널과 터널 직경(D)만큼 근접하여 절리암반 사면을 굴착할 경우에 절리면 경사각과 굴착사면 경사에 따른 굴착 깊이별 터널 근접도를 제시하였다.
more목차
목 차
요 약 문 ⅰ
그림목차 ⅴ
표 목 차 ⅹ
제 1 장 서 론 1
1.1 연구 필요성 및 목적 1
1.2 연구동향 2
1.3 연구내용 및 범위 5
제 2 장 이론적 배경 7
2.1 불연속면에서의 전단거동 7
2.1.1 직접전단시험 시의 응력-변형률 거동 7
2.1.2 불연속면 거칠기의 영향 7
2.1.3 삼축압축시험을 이용한 전단강도 모델 9
2.1.4 구속조건 하의 전단강도 12
2.1.5 구속효과에 따른 전단거동 12
2.1.6 불연속면의 전단강도 모델 14
2.2 터널 주변의 전단영역 18
2.3 터널의 영향범위 21
2.4 지반과 터널라이닝의 강성 23
2.5 암반사면 안정해석 27
2.5.1 원호파괴 27
2.5.2 평면파괴 28
2.5.3 쐐기파괴 30
2.5.4 전도파괴 34
2.6 절리암반의 파괴형태 39
2.7 근접굴착의 근접도 43
제 3 장 대형모형시험 45
3.1 개 요 45
3.2 모형 절리암반의 특성 45
3.3 모형시험 장치 48
3.3.1 모형 토조 48
3.3.2 모형 터널 49
3.3.3 계측 시스템 52
3.3.4 계측 위치 53
3.4 대형모형시험 방법 57
3.4.1 시험 종류 57
3.4.2 절리암반 조성 61
3.4.3 대형모형시험 순서 61
제 4 장 수치해석 64
4.1 개 요 64
4.2 해석 모델 64
4.3 입력 변수 65
제 5 장 모형시험과 수치해석 결과 고찰 70
5.1 개 요 70
5.2 굴착사면 경사에 따른 터널과 절리암반 거동 분석 70
5.2.1 터널 내공변위 71
5.2.2 터널라이닝 모멘트 85
5.2.3 터널라이닝 축력 96
5.2.4 절리암반 지중변위 103
5.3 사면 굴착단계에 따른 터널과 절리암반 거동분석 108
5.3.1 지중변위와 수평토압 108
5.3.2 터널 내공변위와 터널라이닝 모멘트 126
5.3.3 터널거동 원인분석 140
5.4 굴착 깊이에 따른 근접도 제시 146
5.4.1 터널거동에 영향을 미치는 굴착단계 146
5.4.2 궤도틀림 154
5.4.3 굴착 깊이에 따른 근접도 156
제 6 장 결 론 161
참 고 문 헌 164
부 록 168
ABSTRACT 252
목차
LIST OF FIGURE
Fig. 1.1 Trap door testing apparatus (Jian-Hong Wu, 2004) 3
Fig. 2.1 Tangential and normal displacements during a direct shear of
a rough joint 8
Fig. 2.2 Patton's law for the joint shear strength of rock 9
Fig. 2.3 Triaxial test results with jointed specimens 11
Fig. 2.4 The condition between deviations stress and the discontinuity angles 12
Fig. 2.5 Prediction of shear behavior for different confining effect 13
Fig. 2.6 Bilinear model suggested by Patton 15
Fig. 2.7 Nonlinear shear strength model suggested by Barton 16
Fig. 2.8 A circular tunnel in a jointed rock mass under biaxial loading condition 18
Fig. 2.9 Shear sliding zone (B.Shen, 1997) 19
Fig. 2.10 Stress, strain and displacement distributions
in the ground around the tunnel 22
Fig. 2.11 Streamline around the cylinder shape obstacle 23
Fig. 2.12 Effect of flexibility ratio of the tunnel lining 24
Fig. 2.13 Maximum bending moment depending on the stiffness ratio
of ground tunnel lining (Duddeck and Erdmann, 1985) 26
Fig. 2.14 Shape of circular failure and distribution of poles by stereonet 27
Fig. 2.15 Shape of plane failure and distribution of poles by stereonet 28
Fig. 2.16 Stability analysis of plane failure with tension crack 30
Fig. 2.17 Shape of wedge failure and distribution of poles 31
Fig. 2.18 Stability analysis of wedge failure 32
Fig. 2.19 Shape of toppling failure and distribution of poles by stereonet 34
Fig. 2.20 Geometry for limit equilibrium analysis of toppling failure 35
Fig. 2.21 Limit equilibrium condition for toppling and sliding of n-th block 37
Fig. 2.22 Configuration of joint set(Singh, 1997) 40
Fig. 2.23 Modes of failure of jointed mass(Singh et al. 2002) 41
Fig. 2.24 A proximity of tunnel(Side excavation of tunnel, RTRI, 1996) 44
Fig. 3.1 Result of uniaxial compression test 46
Fig. 3.2 Result of normal stiffness test for joint 47
Fig. 3.3 Result of shear stiffness test for joint 47
Fig. 3.4 Schematic diagram of the model test box 48
Fig. 3.5 Front view of the model test box 49
Fig. 3.6 Data acquisition systems used for the model tests 53
Fig. 3.7 Measurement of tunnel displacement 54
Fig. 3.8 Measurement of tunnel lining member forces 54
Fig. 3.9 Location of underground displacement and horizontal earth
pressure sensors 55
Fig. 3.10 Installation of LVDTs for the measurement of displacement 55
Fig. 3.11 Installation of lateral earth pressure sensors 56
Fig. 3.12 Test Cases 58
Fig. 3.13 Excavation step (J30S75 case) 59
Fig. 3.14 Installation of shaped block 61
Fig. 3.15 Test procedure 63
Fig. 4.1 Numerical analysis model by UDEC 65
Fig. 5.1 Displacement of the tunnel lining with slope angle of 0° dip of joint 74
Fig. 5.2 Displacement of tunnel lining with 0° dip of joint (Shallow excavation) 75
Fig. 5.3 Displacement of the tunnel lining with slope angle of 30° dip of joint 76
Fig. 5.4 Displacement of tunnel lining with 30° dip of joint (Deep excavation) 77
Fig. 5.5 A vector diagram of tunnel displacement 0° dip of joint
(Numerical analysis) 78
Fig. 5.6 A vector diagram of tunnel displacement 30° dip of joint
(Numerical analysis) 78
Fig. 5.7 Displacement of tunnel lining with 60° dip of joint 81
Fig. 5.8 Displacement of the tunnel lining with slope angle of 90° dip of joint 82
Fig. 5.9 Displacement of tunnel lining with 90° dip of joint (Deep excavation) 83
Fig. 5.10 A vector diagram of tunnel displacement 60° dip of joint
(Numerical analysis) 84
Fig. 5.11 A vector diagram of tunnel displacement 90° dip of joint
(Numerical analysis) 84
Fig. 5.12 Moment of the tunnel lining with slope angle of 0° dip of joint 86
Fig. 5.13 Moment of the tunnel lining with 0° dip of joint (Deep excavation) 87
Fig. 5.14 Moment of the tunnel lining with slope angle of 30° dip of joint 90
Fig. 5.15 Moment of the tunnel lining with 30° dip of joint (Deep excavation) 91
Fig. 5.16 Moment of the tunnel lining with 60° dip of joint 92
Fig. 5.17 Moment of the tunnel lining with slope angle of 90° dip of joint 94
Fig. 5.18 Moment of the tunnel lining with 90° dip of joint (Deep excavation) 95
Fig. 5.19 Axial force of the tunnel lining with slope angle of 0° dip of joint 100
Fig. 5.20 Axial force of the tunnel lining with slope angle of 30° dip of joint 101
Fig. 5.21 Axial force of the tunnel lining with slope angle of 90° dip of joint 102
Fig. 5.22 Underground horizontal displacement with slope angle
of 0° dip of joint 105
Fig. 5.23 Underground horizontal displacement with slope angle
of 30° dip of joint 106
Fig. 5.24 Underground horizontal displacement with slope angle
of 90° dip of joint 107
Fig. 5.25 Measuring point of horizontal earth pressure with 0° dip of joint 108
Fig. 5.26 Changes in the horizontal earth pressure and horizontal underground
displacement according to excavation steps(J0S60) 111
Fig. 5.27 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J0S75) 112
Fig. 5.28 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J0S90) 113
Fig. 5.29 Measuring point of horizontal earth pressure with 30° dip of joint 114
Fig. 5.30 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J30S60) 116
Fig. 5.31 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J30S75) 117
Fig. 5.32 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J30S90) 118
Fig. 5.33 Measuring point of horizontal earth pressure with 60° dip of joint 119
Fig. 5.34 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J60S60) 120
Fig. 5.35 Measuring point of horizontal earth pressure with 90° dip of joint 121
Fig. 5.36 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J90S60) 123
Fig. 5.37 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J90S75) 124
Fig. 5.38 Changes in the horizontal earth pressure and horizontal underground
displacement during excavation steps(J90S90) 125
Fig. 5.39 Displacement and moment of tunnel lining by excavation steps
with J0S60 130
Fig. 5.40 Displacement and moment of tunnel lining by excavation steps
with J0S75 131
Fig. 5.41 Displacement and moment of tunnel lining by excavation steps
with J0S90 132
Fig. 5.42 Displacement and moment of tunnel lining by excavation steps
with J30S60 133
Fig. 5.43 Displacement and moment of tunnel lining by excavation steps
with J30S75 134
Fig. 5.44 Displacement and moment of tunnel lining by excavation steps
with J30S90 135
Fig. 5.45 Displacement of tunnel lining by excavation steps
with 60° dip of joint 136
Fig. 5.46 Moment of the tunnel lining by excavation steps
with 60° dip of joint 136
Fig. 5.47 Displacement and moment of tunnel lining by excavation steps
with J90S60 137
Fig. 5.48 Displacement and moment of tunnel lining by excavation steps
with J90S75 138
Fig. 5.49 Displacement and moment of tunnel lining by excavation steps
with J90S90 139
Fig. 5.50 Principal stress distribution by numerical analysis(J0S60) 141
Fig. 5.51 Principal stress distribution by numerical analysis(J30S75) 143
Fig. 5.52 The excavation step of maximum tunnel deformation
at 0° dip of joint 147
Fig. 5.53 The excavation step of maximum tunnel deformation
at 30° dip of joint 149
Fig. 5.54 The excavation step of maximum tunnel deformation
at 60° dip of joint 151
Fig. 5.55 The excavation step of maximum tunnel deformation
at 90° dip of joint 153
Fig. 5.56 Excavation depth at proximity diagram of tunnel 158
Fig. 5.57 A proximity diagram with excavation depth with slope angle 60° 159
Fig. 5.58 A proximity diagram with excavation depth with slope angle 75° 159
Fig. 5.59 A proximity diagram with excavation depth with slope angle 90° 160
LIST OF TABLE
Table 2.1 Modes of failure in jointed mass(M., Singh, 2004) 42
Table 2.2 Type and feature of adjacent construction 43
Table 3.1 Mechanical properties of block and joint 46
Table 3.2 Stiffness ratio and thickness of the tunnel lining model 51
Table 3.3 Reduction ratio of the model test 52
Table 3.4 Data acquisition system 52
Table 3.5 Measuring sensors 53
Table 3.6 Type of tests 58
Table 4.1 Mechanical properties of MC model and BB model 66
Table 4.2 Mechanical properties of the block 67
Table 4.3 Mechanical properties of the discontinuities 69
Table 4.4 Mechanical properties of the tunnel lining 69
Table 5.1 Maximum displacement of the tunnel lining with slope angle
(dip of joint : 0°, 30°) 72
Table 5.2 Maximum displacement of the tunnel lining with slope angle
(dip of joint : 60°, 90°) 80
Table 5.3 Maximum moment of the tunnel lining with 0° dip of joint 85
Table 5.4 Maximum moment of the tunnel lining with 30° dip of joint 89
Table 5.5 Maximum moment of the tunnel lining with 90° dip of joint 93
Table 5.6 Maximum axial force of the tunnel lining with 0° dip of joint 96
Table 5.7 Maximum axial force of the tunnel lining with 30° dip of joint 97
Table 5.8 Maximum axial force of the tunnel lining with 90° dip of joint 98
Table 5.9 Displacement and moment of tunnel lining during excavation
with 0° dip of joint 126
Table 5.10 Displacement and moment of tunnel lining during excavation
with 30° dip of joint 128
Table 5.11 Displacement and moment of tunnel lining during excavation
with 60° dip of joint 128
Table 5.12 Displacement and moment of tunnel lining during excavation
with 90° dip of joint 129
Table 5.13 The excavation steps of tunnel member force and displacement
increased sharply (dip of joint 0°) 146
Table 5.14 The excavation steps of tunnel member force and displacement
increased sharply (dip of joint 30°) 148
Table 5.15 The excavation steps of tunnel member force and displacement
increased sharply (dip of joint 60°) 150
Table 5.16 The excavation steps of tunnel member force and displacement
increased sharply (dip of joint 90°) 152
Table 5.17 Track maintenance standard on train 154
Table 5.18 Track maintenance standard for alignment on high speed train 155
