Qatar
| Participants | |
|---|---|
| Owner | QDVC Qatar |
| Contractor | Bauer International for 3 Tunnels |
| Location of the Job Site | Doha, Katar, Al Matar Station |
| Tender | |
| Short Description of Job | Pipe roofs for 8 tunnel projects comprising 23 canopy pipe drills up to 74 m long |
| Specifications for Tenders | 8 tunnel 23 drills per tunnel with steel pipes OD 508 mm wall thickness 10 mm Single pipe length between 6 and 12 m, joints fully welded Steel pipes to be installed in partially weathered limestone up to 50 MPa accuracy required vertical ± 100 mm, horizontal ± 50 mm |
| Alternative Methods proposed by the Constructor | Front Steer with DTH hammer and optical guiding system Front Steer with flat drilling head and optical guiding system |
| Ground conditions | |
| Described Ground in the Ground Report | Partially weathered Limestone with Uniaxial Compressive Strength up to 30 MPa |
| Encountered Soils | Partially weathered Limestone with Uniaxial Compressive Strength up to 50 MPa |
| Depth of Coverage | Varies between 5 and 6 m underneath the motorways |
| Accuracy | Vertically ±100 mm, Horizontally ±50 mm |
| Time for Job or Production Rate | Production rates: 4 to 6 m/hour for Front Steer with flat drilling head and 6 to 10 m/h for Front Steer with down-the-hole hammer, timeframe to complete one 72 m long drive 48 hours, machines operated in two shifts |
| Driving Length | 60 to 74 m |
| Any other Specifics | Guided auger boring with DTH hammer and optical guiding system Very high requirements for the accuracy Very small distances between the pipes |
Bohrtec Gesellschaft für Bohrtechnologie mbH
Konrad-Zuse-Straße 24
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+49 (0) 2404 9881 - 0
+49 (0) 2404 9881 - 10
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