| Bore diameter | m |
|
| Material strength | MPa |
Rock - Unconfined uniaxial compressive strength qu (MPa) |
| Electric Motor | kw |
| 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 |
References:
