ABSTRACT
NOTES Notes There are so many factors, apart from design considerations, which influence the cost of tunnelling that it is only possible to give guide prices for a sample of the work involved. For more reliable estimates it is advisable to seek the advice of a Specialist Contractor. The main cost considerations are : * the nature of the ground * size of tunnel * length of drive * depth below surface * anticipated overbreak * support of face and roof of tunnel (rock bolting etc.) * necessity for pre-grouting * ventilation * presence of water * use of compressed air working The following rates for mass concrete work cast in primary and secondary linings to tunnels and access shafts are based on a 5.0 m depth of shaft and 15.0 m head of tunnel Apply the following factors for differing depths and lengths : HEAD LENGTH: 15 m 30 m 60 m 90 m Shaft depth 5m +0% +10% +20% +32½% Shaft depth 10m +5% +12½% +27½ +35% Shaft depth 15m +10% +17½% +32½%+40% Shaft depth 20m +15% +20% +37½%+42½% EXCAVATION Excavating tunnels in rock 1.5 m diameter - - - - m3 479.21 3.0 m diameter - - - - m3 298.26 Excavating tunnels in soft material 1.5 m diameter - - - - m3 226.79 3.0 m diameter - - - - m3 125.59 Excavating shafts in rock 3.0 m diameter - - - - m3 183.10 4.5 m diameter - - - - m3 155.25 Excavating shafts in soft material 3.0 m diameter - - - - m3 107.26 4.5 m diameter - - - - m3 91.78 Excavating other cavities in rock 1.5 m diameter - - - - m3 479.21 3.0 m diameter - - - - m3 298.26 Excavating other cavities in soft material 1.5 m diameter - - - - m3 226.79 3.0 m diameter - - - - m3 125.59 Excavated surfaces in rock - - - - m2 17.46 Excavated surfaces in soft material - - - - m2 17.46
Item
Gang hours
Labour £
Plant £
Material £ Unit
Total rate £
IN-SITU LINING TO TUNNELS Notes The following rates for mass concrete work cast in primary and secondary linings to tunnels and access shafts are based on a 5.0 m depth of shaft and 15.0 m head of tunnel See above for additions for differing shaft depths and tunnel lengths. Mass concrete; grade C30, 20 mm aggregate Cast primary lining to tunnels 1.5 m diameter - - - - m3 291.99 3.0 m diameter - - - - m3 249.26 Secondary lining to tunnels 1.5 m diameter - - - - m3 336.62 3.0 m diameter - - - - m3 266.12 Formwork; rough finish Tunnel lining 1.5 m diameter - - - - m2 46.82 3.0 m diameter - - - - m2 46.82 IN-SITU LINING TO ACCESS SHAFTS Notes The following rates for mass concrete work cast in primary and secondary linings to tunnels and access shafts are based on a 5.0 m depth of shaft and 15.0 m head of tunnel See above for additions for differing shaft depths and tunnel lengths. Mass concrete; grade C30, 20 mm aggregate Secondary linings to shafts 3.0 m int diameter - - - - m3 266.91 4.5 m int diameter - - - - m3 260.72 Cast primary lining to shafts 3.0 m int diameter - - - - m3 285.60 4.5 m int diameter - - - - m3 272.51 Formwork; rough finish Shaft lining 3.0 m int diameter - - - - m2 71.11 4.5 m int diameter - - - - m2 48.38 IN-SITU LINING TO OTHER CAVITIES Notes The following rates for mass concrete work cast in primary and secondary linings to tunnels and access shafts are based on a 5.0 m depth of shaft and 15.0 m head of tunnel See above for additions for differing shaft depths and tunnel lengths.
