TBM

TBMTUNNEL BORING MACHINE

INTRODUCTION

Atunnelis an underground passageway, completely enclosed except for openings for egress, commonly at each end.

A tunnel may be for road traffic,,canal,hydroelectric station,sewer etc.TheDelaware Aqueductin New YorkUSAis the longest tunnel, of any type, in the world at 137km (85mi)

REQUIRMENTS OF TUNNELIT IS VERY USEFUL WHERE BRIDGE FAIL TO FULFILL REQUIRMENTS LIKE IN SEA ,IN URBAN AREA ,AND IN MOUNTAINS.

EFFICIENT COPARED TO BRIDGES. IN WAR TIME IT IS MUCH DIFFICULT TO DESTROY A TUNNEL BUT DESTRUCTION OF BRIDGE IS TOO EASY.

LOTS OF LAND AND TIME IS SAVED.

TUNNEL BORING MACHINEtunnel boring machine (TBM) is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strataThey can bore through anything from hard rock to sandTunnel diameters can range from a metre to 19.25metre

DRILL AND BLAST1.Before the advent oftunnel boring machines,drilling and blastingwas the only economical way of excavating longtunnelsthrough hard rock, where digging is not possible.

2.Even today, the method is still used in the construction of tunnelsBut the disadvantage is it disturbance the sorroundings

HOW DRILL AND BLAST IS BEING DONE

HISTORYThe first successful tunnelling shield was developed by Sir Marc Isambard Brunel to excavate the Thames Tunnel in 1825

In the United States, the first boring machine to have been built was used in 1853 during the construction of the Hoosac Tunnel.

MAIN PARTS OF TBM

WORKING OF TBMA TBM is shaped like a tube. At the front is a rotating disk with cutting teeth that can shear through rockThe pulverized rock falls to a conveyor belt that carries it to the back of the TBMHydraulic feet grip the sides of the tunnel and push the machine forwardThere is also the ability to insert plates to line the interior of the tunnel

How its work

ADVANTAGE Higher advance ratesContinuous operationsLess rock damageLess support requirementsUniform muck characteristicsGreater worker safetyPotential for remote, automated operation.

DISADVANTAGEThe major disadvantage is the upfront costTBMs are expensive to construct, and can be difficult to transport.TBM can not move in backward directionTBMs are expensive to construct, and can be difficult to transport.

APPLICATION1.IN ROAD TRAFFICS2.IN SEWERS3.IN MININGS4.IN RAIL TRAFFICS5.IN HYDROELECTRIC STATIONS

CONCLUSIONThe main purpose for any organisation is that provide safe environment for worker and TBM is more control and safe than drilling and blasting