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Cut-and-cover construction at Saint-Michel on Paris Métro Line 4 (c. 1910) Cut-and-cover is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. [29] There are two basic forms of cut-and-cover ...
Tunnel Construction. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management.
A sidehill cut can be formed by means of sidecasting, i.e., cutting on the high side balanced by moving the material to build up the low side to achieve a flat surface for the route. In contrast, through cuts, where the adjacent grade is higher on both sides of the route, require removal of material from the area since it cannot be dumped ...
An alternative to digging trenches is to create a utility tunnel. Such a tunnel may be dug by boring or by using a trench for cut-and-cover construction. The advantages of utility tunnels are the reduction of maintenance manholes, one-time relocation, and less excavation and repair, compared with separate cable ducts for each service.
Also amphidrome and tidal node. A geographical location where there is little or no tide, i.e. where the tidal amplitude is zero or nearly zero because the height of sea level does not change appreciably over time (meaning there is no high tide or low tide), and around which a tidal crest circulates once per tidal period (approximately every 12 hours). Tidal amplitude increases, though not ...
Welwyn North Tunnel was the scene of a major accident in 1866: 1850: Hertfordshire: Welwyn South Tunnel: Railway: 408: 446: 1850: Hertfordshire: Weston Hills Tunnel: Road: 230: 250: Cut-and-cover tunnel on the A505 [29] 2006: Hertfordshire: Watford Tunnels: Railway: 1660: 1,815: Part of the West Coast Main Line, first built for the London and ...
A secret tunnel discovered last week on the U.S.-Mexico border will be sealed by Mexican authorities, an army official in Ciudad Juarez said Saturday. The tunnel, discovered on Jan. 10, connects ...
Spencer Dock to Inchicore - dual bored tunnel. Metro North, Dublin. St. Stephen's Green to Ballymun dual bored and twin cut and cover tunnel. Metro North, Dublin. Dublin Airport - dual bored tunnel. Metro North, Dublin. Fosterstown Underpass - short twin cut and cover tunnel. Irish Sea Tunnel - hypothetical.