Table of Contents
8.1.5 tunnel (2)
8.1.5.1 type of tunnel (2)
8.1.5.1.1 classified by construction method (2)
8.1.5.1.2 classified by shape of cross-section (2)
8.1.5.2 construction method (3)
8.1.5.2.1 construction procedure (3)
8.1.5.2.2 TBM method (4)
8.1.5.2.3 dill and blast (5)
8.1.5.2.4 cut and cover (7)
8.1.5.2.5 ventatilation (8)
8.1.5.2.6 lighting system (9)
8.1.5.2.7 tunnel finishes (9)
8.1.5.3 glossary (10)
8.1.5 tunnel
8.1.5.1 type of tunnel
8.1.5.1.1 classified by construction method
8.1.5.1.2 classified by shape of cross-section
8.1.5.2 construction method 8.1.5.2.1 constructionprocedure
8.1.5.2.2 TBM method
What tmbis:
What parts included in TMB
Modern TBMs typically consist of the rotating cutting wheel, called a cutter head, followed by a main bearing, a thrust system and trailing support mechanisms.
What soil conditions applied in
In hard rock, either shielded or open-type TBMs can be used. All types of hard rock TBMs excavate rock using disc cutters mounted in the cutter head.
In fractured rock, shielded hard rock TBMs can be used, which erect concrete segments to support unstable tunnel walls behind the machine.
In soft ground, there are three main types of TBMs: Earth Pressure Balance Machines (EPB), Slurry Shield (SS) and open-face type. Both types of closed machines operate like Single Shield TBMs, using thrust cylinders to advance forward by pushing off against concrete segments.
Merit and weakness
TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in heavily urbanized areas. The major disadvantage is the upfront cost. TBMs are expensive to construct, and can be difficult to transport. TBMs is much more efficient and results in shortened completion times (when they operate successfully).
TBM procedure
8.1.5.2.3 dill and blast
What dill and blast method is
Drilling and Blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often
in mining, quarrying and civil engineering such as dam or road construction.
Type of drill and blast
TYPE 1 :Twin sidewall drift face excavation
TYPE 2 :Single sidewall drift face excavation
TYPE 3 :Crown, bench and invert face excavation procedureof drill and blast method
