29-08-2011, 02:55 PM
TUNNEL BORING MACHINE.ppt (Size: 1.77 MB / Downloads: 770)
INTRODUCTION
Tunnel Boring Machine (TBM) also known as ‘MOLE’.
It is used to excavate tunnels with a circular cross section.
It can bore through anything from hard rock to sand.
Different types of TBMs are used for different geotechnology.
Used as an alternative to drilling and blasting (D&B) methods and conventional 'hand mining' in soil
Limits the disturbance to the surrounding ground and produces a smooth tunnel wall.
Suitable to use in heavily urbanized areas.
TBMs is also a complete single unit moving factory
Only little finishing work has to be done after using TBMs as this single unit can do
DRILLING SYSTEMS
CONCREATE SPRAYING
SEGMENTAL LINING
ROCK SUPPORTING
PIPE JACKING
CONVEYANCE OF EXCAVATED MATERIAL
GEOTECHNOLOGY
The geological and hydraulic information about the soil forms the basis for planning and executing tunnelling and pipe jacking projects.
Provide the basic data for selecting tunnelling methods and cutting wheel tools that will cut through the native ground efficiently and economically.
The most important ground or rock-mechanical parameters for designing a tunnel boring machine are:
-grading curve -rock/clay mineralogy
-ground water penetration -quality of the rock
-consistency limits -hardness of the rock
CUTTING ROLLS
Cutting rolls are used to tear of the soil and rock from tunnel face.
They are mounted on the cutting heads.
Different types of materials are used for different ground condition.
They are placed radially, so as to have maximum efficiency.
They can revolve themselves in full 360 degree.
They can be replaced periodically.
They presses the tunnel face with a force of 26 tons