28-11-2012, 04:18 PM
Tunnel Construction
tunnel_construction fr pics.pdf (Size: 6.57 MB / Downloads: 318)
Entrance arrangement to the tunnel portal for the 3.7km long Tai
Lam Tunnel of Route 3 at Kam Tin as seen in early 1996. Tai
Lam Tunnel consists two main tunnels, each measures 15.5m wide
and 10.5m high, and a 950m long servicing duct for ventilation
and other supply purposes in between the main tunnels.
Drawing showing the excavation sequences using the New Austrian Tunnel Method. The principle of constructing large sectioned tunnel using this method is to subdivide the tunnel section into several arched smaller sections for the sake of easier control and safer supporting during excavation. The newly formed surfaces are often required to temporary supported by girder sections, shotcrete, nails or anchors.
After the tunnel formed by drill and blast process, the newly
formed tunnel surface is to be lined with an in-situ concrete lining
to stabilize the exposed soil or rock faces. The photo shows the
gantry-type formwork used to form the in-situ concrete lining.
Tunnel portal during the process of tunnel excavation can serve several
purposes: to provide an entrance into the tunnel tube to facilitate the
movement of tunneling equipments and materials; as an exit for the disposal of
spoils; to form a ramp into the tunnel tube which is usually at sub-grade level;
or to provide supporting space for the temporary storing or assembling of
equipments. This photo shows a traveling-type working gantry is being
assembled inside the portal area of Kwai Tsing Tunnel at Mei Foo side.