Tunnel boring and pipe jacking
Bore diameter
Material strength
Rock - Unconfined uniaxial compressive strength qu (MPa)
Tunnel boring machine (TBM) drilling productivity*
Drilling productivity only 0.00 m/shift 10hr shift
** As a rule of thamb 1/3 of the drilling production rate, equates to the total installation production rate
Indicative boring cycle times References
Excavation 33.3 % Howarth, 1981
Pipe installation 10 % Bruland, 1998
Jacking speed 20 % Cheema, 1999
Locomotive Travel Time 6.7 % Gong and Zhao, 2009
Drill repairs and maintenance 30 %
Production rates relative to TBM selection m/shift m/day m/week m/month
Total MTBM productivity per shift (Pipe jacking) 0.00 0.00 0.00 0.00
Gripper TBM for hard rock 0.00 0.00 0.00 0.00
Slurry TBM (Earth Pressure Balance) SPT N-value(blows/300mm) to determin Density Index (Relative Density) i.e. kPa = N-value x 2 0.00 0.00 0.00 0.00
It has been well recognized that joints or fractures have an important effect on the TBM performance (Howarth, 1981, Bruland, 1998, Cheema, 1999, Gong and Zhao, 2009). The discontinuities can facilitate rock breakage, because cracks induced by TBM cutters easily develop with the existing discontinuities. On the basis of a large number of case studies, Bruland (1998) concluded that with the decrease of joint spacing, the TBM penetration increases distinctly.
Hard rock cutter disk abrasivity.
Granite 180MPa with high quartz content 55% to 70% 30 m3/disk
Granite 120MPa with high quartz content 55% to 70% 37.3 m3/disk
Granite 120MPa 100 m3/disk
Granite 230MPa with high quartz content 55% to 70% 10 m3/disk

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