TBMs for Norwegian Hydropower projects Sindre Log The Robbins Company
Who am I? Sindre Log M.Sc. Civil engineering, NTNU Specializations in tunneling, geology and Project management Working out of Oslo, Norway
60 YEARS OF EXPERIENCE The Robbins Company Started in 1952 Invented the first Main Beam and Double Shield TBMs First disc cutters to bore hard rock Epic projects:; - Channel Tunnel - Niagara falls (14,5m)
60 YEARS OF EXPERIENCE Robbins Europa / ITALY Roboretec / ROMANIA Robbins China / SHANGHAI Robbins China / GUANGZHOU Robbins Asia Pacific / HONG KONG Robbins GmbH / GERMANY Robbins India / NEW DELHI Robbins España / MADRID Robbins Mexico / MEXICO CITY Robbins TBM Korea / SEOUL Robbins South America / CHILE Plus representatives in 35 countries
Outline Norwegian TBM history Introduction to TBMs Advantages/Disadvantages of TBMs in Hydropower Conclusive remarks
Norwegian TBM history
Norwegian TBM History (1972-1992)
Type of projects
Meråker HEPP (1991-1992) Total of 44km Tunnel 10 km in less than 12 months Cambrian and Ordovician metamorphic sediments with metagabbro intrusions. Average of more than 1000m per month Finished 9 months ahead of schedule
Introduction of TBMs
What is a Tunnel boring machine (TBM)? Mechanized tunneling method for tunnels in soft or hard ground conditions Hard rock TBMs are produced in diameters from 2-16m Small Boring units from 600mm, but boring length/incline is restricted.
General parts of a Main beam TBM
Cutters Max loading depending on size. 19 cutters have a maximum load of 312 KN 10,2 m TBM = 67 Cutters*312kN = 21000 Kn
Rock breaking principles
Chip rock breaking principles
Muck removal
Muck Removal
INNOVATION IN ACTION Conveyor Custom conveyors are designed and manufactured for each project Stacker conveyor Vertical conveyor Horizontal conveyor Alternatives; - Muck trains - Rubber wheel transport
Rock Support
Need for rock support - LCC
Main rock support for Norwegian conditions: Probing and pregrouting Rock bolting Robbins slat system (McNally System) Light Shotcrete Heavy Shotcrete Concrete segments Cast Concrete
TBMs for Hydropower
Main advantages of TBM for Hydro electric power projects Surface roughness/ Reduction of cross section Tunnel Quality Penetration rates Enviromental aspects
Surface roughness
Reduced Cross sections
Blasted vs TBM Cross section
Reduced cross section Less material to excavate Potential to realize marginal -projects Could realize projects which is challenging due to topography Mimimum economical D&B cross section is 16-20 m2 TBM can be 3-5m2
Tunnel quality
Tunnel quality Less rock support Life cycle costs (LCC Maintenance) Less rock fall Less damage on nearby constructions during excavation (Refurbishment of old HEPP)
Penetration rates
Penetration rate
Penetration rates As the penetration per adit is signficantly higher than D&B, there is a big advantage in using TBMs if the access is limited In Norwegian conditions monthly avereage production rates should be 500m-1200m depending on the TBM size and geology
Enviromental aspects Could be run on 100% green energy Better work enviroment Less excavated material to deposit Smaller enviromental interventions Less impacts on external enviroments
Disadvantages with TBMs Less flexibility Longer delivery times (6-12 Months) Higher upfront investment
Higher investment costs
Norwegian registered leasing company started in late 2012, with Robbins as a part owner Provides an opportunity to consider TBMs without writing off the whole TBM over the project Reduces the economically feasible tunnel length for TBMs significantly Stand outside the conference room
Concept for Norwegian hydro
Customized MB-TBM for all concepts
Customization 2.2m Chosen to be able to utlize 17 cutter (250 kn/c) for hard Norwegian rock types Anti-slip gripper system for high inclines Container based conveyor system for easy assembly and dissassembly Special battery driven man rider to bring people and personel Customized muck removal system to allow excavation above 30 degrees incline.
Conclusive remarks
Current situation «Det er et behov, og TBM vil sannsynligvis komme inn igjen, men å kalle det ny vår er kanskje litt tidlig. Det er vel heller en senvinter der det begynner å løsne. Bransjen har for lite kunnskap, siden det er så lite brukt» Prof. Amund Bruland, NTNU, Teknisk ukeblad 27.02.2013
Conclusive remarks With the advantages of TBMs for Hydropower and the projects coming there is no reason why TBMs should not be as competitive as in the previous TBM era Initial interest from all parts of the industry, including contractors, consultants and academia.
Take away point Don t bother to much about the problems, concentrate on the possibilities, there are always people who will focus on the problems Prof. Odd Johannessen, NTNU
Det første vårtegn
Takk for oppmerksomheten! Sindre Log Sivilingeniør The Robbins Company logsindre@robbinstbm.com