realistic synthetic key block analysis to compare ... · realistic synthetic key block analysis to...
TRANSCRIPT
REALISTIC SYNTHETIC KEY BLOCK ANALYSIS TO
COMPARE DIFFERENT SUPPORT SCENARIOS
OH
MS C
on
sultan
cy Divisio
n
METHODOLOGY
Methodology
Geotechnical data
• Data gathering.
• Stereographic projections and discontinuity analysis.
• Statistical analysis, processing and quality control.
Key block analysis input
parameters
• Key block creation
• Define a support scenario
• Hazard Analysis
• Correlation between FOG database and synthetic database
Comparative key block analysis
• Compare different support scenarios
GEOTECHNICAL DATA Geotechnical
data
• Data gathering.
• Stereographic projections and discontinuity analysis.
• Statistical analysis, processing and quality control.
Geotechnical Data
• Data gathering.
Mining Direction
Dip
Strike Scan Line
Dip
Sca
n L
ine
Geotechnical Data
• Data gathering.
• Stereographic projections and discontinuity analysis.
Friction Angle
• Point Estimate Method applied to the Barton and Bandis equation.
• JCS derived from Schmidt hammer rebound number.
• σn estimation can be derived from Examine 2D.
• JRC is derived from field observations.
Geotechnical Data
• Data gathering
• Stereographic projections and Discontinuity analysis
• Statistical analysis, processing and quality control.
Joint Data 1
Joint Data 2
KEY BLOCK ANALYSIS INPUT PARAMETERS Key block
analysis input parameters
• Key block creation
o Key block creation limits
o Generate 100 000 key blocks
• Define a support scenario
o Represent support used inside the time period of FOG database
• Run Hazard Analysis
o Block filtering: tall thin block clamping
• Correlation between FOG database and synthetic database
o Fallout distribution of volume
Project flow of JBlock
• Now we have a geo-domain
• Build excavation
• Generate key-blocks o Creation limits
• Define support scenario o In-use at time of FOG DB
o External loading
Stress in skin of excavation
• Run hazard analysis
o Block filtering
Key block creation limits
• Block creation
o Max aspect ratio considered
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
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0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
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Bin
Aspect Ratio: Longest Edge
Series1
Series2
Aspect ratio = longest edge/volume1/3 Max =5.4
FOG database
Project flow of JBlock
• Now we have a geo-domain
• Build an excavation
• Generate key-blocks o Creation limits
• Define support scenario o In-use at time of FOG DB
o External loading
Stress in skin of excavation
• Run hazard analysis o Block filtering
Analyse a support scenario
Filter blocks for clamping or extreme size…
Batch run several scenarios
Filter block sizes/clamping to use in analysis
Block filtering input parameters
• Block filtering
o Tall thin block clamping
Mid height
Height to face area ratio
Block filtering: Mid height
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
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0.1
0.2
0.3
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0.5
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0.9 1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9 3
3.1
3.2
3.3
3.4
3.5
3.6
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Bin
Histogram: Thickness
Series1
Series2
Mid height = Max thickness / 2 Max = 3.5
Mid height = 1.75
Block filtering: Height to face area ratio
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
100.00%
0
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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
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Height to face area ratio
Series1
Series2
Height to face area ratio = thickness/face area1/2 Max =1.1
Is the synthetic database realistic? • Block creation
oMax aspect ratio considered
• Block filtering o Mid height
o Height to face area ratio
• Correlation: FOG database vs synthetic database o Compare different clamping stresses
Correlation Coefficient
Kolmogorov-Smirnov: Two Sample Test
Clamping Correlation
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
4
4.6
5.2
5.8
6.4 7
7.6
8.2
8.8
9.4 10
10
.6
11
.2
11
.8
12
.4 13
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.6
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.2
14
.8
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.4 16
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.6
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.2
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.8
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.4 19
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.6
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.2
20
.8
21
.4 22
22
.6
23
.2
23
.82
4.4 25
25
.6
26
.2
26
.8
27
.4 28
Fallout: Volume
Clamping Correlation: Volume
2kPa
4kPa
6kPa
8kPa
10kPa
Actual: FOG DB
40% 80%
Clamping Correlation
Clamping Stress [kPa]
Correlation coefficient [%]
Max Error [%]
Avg Error [%]
2 92% 38% 15% 4 92% 38% 17% 6 94% 32% 16% 8 96% 27% 9%
10 94% 30% 15%
Kolmogorov-Smirnov: Two Sample Test
Correlation coefficient
Clamping Correlation
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2 4 6 8 10
Clamping Stress [kPa]
Correlation: Clamping Stress
Correlation
MaxD
COMPARATIVE KEY BLOCK ANALYSIS
Comparative key block analysis
• Compare different support scenarios
• Compare support strategies
• Different tendon lengths.
• Optimize support spacing
When analyzing a support scenario
• Evaluate blocks that can fail
• This implies that we want to evaluate: – Stable by support – Failed support – Failed by rotation – Failed between support
• We don’t want to take into account: – Stable over solid – Stable by friction – Stable no sliding – Tall clamped blocks
Support Comparison
RESULTS EXPRESSED AS FALLS PER 10 000m2
What is driving the Mode of Failure?
What is driving the Support Failure?
Size distributions of failed key blocks?
Different tendon lengths?