Ground Penetrating Radar

Ground Penetrating Radar
Anne Lalagüe
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3D - Georadar
ƒ GeoScopeTM GPR
ƒ 100 Mhz – 3 Ghz
ƒ 31 elements
ƒ Scan width: 2,25 m
ƒ RoadDoctorTM
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3D – Georadar
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Penetration depth
Depends on:
1.
GPR frequency
High frequency : penetration depth բ , resolution ա
Low frequency : penetration depth ա , resolution բ
2.
Conductivity of materials
Low: penetration depth ա (sand, rocks, plastic, ice...)
High: penetration depth բ (metal, clay, saline soils)
Usually : ≈ 3m
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Determination of space behind
concrete lining in tunnels using GPR
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Determination of space behind concrete
lining in tunnels using GPR
After the accident in Hanekleiva tunnel, it was decided to inspect the rock surface behind frost insulating walls in all tunnels in Norway.
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Determination of space behind concrete
lining in tunnels using GPR
These walls where not designed with inspection hatches and the distance between the wall and the rock surface is in most cases not known.
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Determination of space behind concrete
lining in tunnels using GPR
1m/1,5m
high
002
003
004
001
2m/2,5m high
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Determination of space behind concrete
lining in tunnels using GPR
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Roads and Pavements
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E14 – E39
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E14 – E39
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E14 – E39
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E14 – E39
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Location of peat in Helgeland
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Location of pipes
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Location of pipes
Distance
(m)
80
145
170
226
338
360
478
504
542
592
Depth
(m)
1,1
1,1
1,1
1,6
1,2
1,3
1,0
1,1
1,1
1,6
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Location of culvert
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PhD Projects
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Location of the frost line by GPR - SIP
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FV 512 - hp01: Wintertime (March)
Frost line
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FV 512 - hp01: Springtime (April)
Frost line
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FV 512-hp01 : summertime (July)
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FV 512-hp01 : Cross sections
winter
spring
summer
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Depth8 [m]
1
1,2
1,4
1,6
1,8
2
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510
498
482
469
454
441
429
415
400
381
363
349
339
329
313
297
284
270
255
243
230
216
204
190
174
160
146
131
116
104
90,9
78,2
67,2
54,8
44,7
34
21,9
11
1,21
Frost lines: exported to Excel
Distance [m]
0
0,2
0,4
0,6
0,8
Winter
Spring
Also:
ƒ
Data accuracy
ƒ
Pipe leakages
ƒ
SmartSalt
Soon:
ƒ Tunnel investigation
ƒ Railway ballasts
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Thank you for your attention
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