Tunnel boring machines123

TUNNEL BORING MACHINES

CONTENTS INTRODUCTION REQUIREMENTS OF TUNNEL MAIN PURPOSES PROCEDURES INVOLVED METHODS OF TUNELLING INSTRUMENTATION USEDMETHOD TO SELECTION THE OTHER SIDE

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for road traffic,road traffic,canal,hydroelectric station,sewer etc.The Delaware Aqueduct in New York USA is the longest tunnel, of any type, in the world at 137 km (85 mi) it is very useful where bridge fail to fulfill

requirements like in sea ,in urban area

and in mountains. efficient when compared 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.

INTRODUCTION

WHAT IS A TUNNEL?

MAIN PURPOSES

IN ROAD TRAFFICSIN SEWERSIN MININGIN RAIL TRAFFICSIN HYDROELECTRIC STATIONS ETC.

THE PROCESS FOR BORED TUNNELLING INVOLVES ALL OR SOME OF THE

FOLLOWING OPERATIONS:Probe drilling (when needed)Grouting (when needed)Excavation (or blasting) SupportingTransportation of muckLining or coating/sealingDrainingVentilation

PROBE DRILLINGThis type of drilling is done in order to

find out suitable method for drillingIt consist of drilling in sample, by

various method to find most suitableIt is necessary part of all drilling

operation .

GROUTINGIt is the process of providing

additional support to drilled mine.

It is done by a liquid called grout ,consist of water ,cement ,color tint and sometime fine gravel .

Good surface is achieved .EXCAVATIONExcavation is the digging and

recording of artifacts at an archaeological site.

It is necessary to know the archaeological importance of a site before digging .

This is performed by experts in a scientific way.

Many governments grants permission for tunneling after finding a go certificate in excavation.

SUPPORTING After initial mining , tunnel need supports

for further processing .For the sake of life a perfect planning is

needed for support. In ancient time timber and masonry were

the main methods.Today support is provided by injecting final

pipe or building it completely before further tunneling

TRANSPORTATION OF MUCKIn ancient time transportation was

done by steam engine and by Manual transport.

Today it is done by modern methods and process is automatic .

TBMs are also come with proper arrangment for the transport of muck.

LINING OR COATINGLining of proper material is done by

modern methods like polishing ,painting to prevent wear and tear and corrosion.

Very necessary part where corrosive metals are being used.

DRAININGDraining is the process to remove the

water or other liquid from working site Very important where water level is

very high.Pumps and pipes are used for this

purpose.

VENTILATION Proper ventilation is required for

safety of workers.This is done by proper checking of

oxygen and other parameters .Proper installations for exit of

hazardous gasses coming out from tunneling .

TUNNEL CONSTRUCTION METHODS:

Classical methods Cut-and-cover Drill and blast Tunnel boring machines (TBMs) Immersed tunnels Tunnel jacking Other methods .

CLASSICAL METHODS

Among the classical methods are the Belgian, English, German, Austrian, Italian and American systems. These methods had much in common with early mining methods and were used until last half of the 19th century.

Excavation done by hand or simple drilling equipment.

Supports were predominantly timber, and transportation of muck was done on cars on narrow gauge tracks

Progress was typically in multiple stages The lining would be of brickwork.

These craft-based methods are no longer applicable.

THE ENGLISH METHOD

Crown-bar method- started from a central top heading which allowed two timber crown bars to be hoisted into place, the rear ends supported on a completed length of lining, the forward ends propped within the central heading. Development of the heading then allowed additional bars to be erected around the perimeter of the face with boards between each pair to exclude the ground. The system is economical in timber, permits construction of the arch of the tunnel in full-face excavation, and is tolerant of a wide variety of ground conditions, but depends on relatively low ground pressures.

THE AUSTRIAN (CROSS-BAR) METHOD required a strongly constructed central bottom heading upon which a crown heading was constructed. The timbering for full-face excavation was then heavily braced against the central headings, with longitudinal poling boards built on timber bars carried on each frame of timbering. As the lining advanced, so was the timbering propped against each length to maintain stability. The method was capable of withstanding high ground pressures but had high demand for timber.

THE GERMAN METHOD (core-leaving method) provided a series of box headings within which the successive sections of the side walls of the tunnel were built from the footing upwards, thus a forerunner of the system of multiple drifts. The method depends on the central dumpling being able to resists without excessive movement pressure transmitted from the side walls, in providing support to the top 'key' heading prior to completion of the arch and to ensuring stability while the invert arch is extended in sections.

THE BELGIAN SYSTEM (underpinning or flying arch method) started from the construction of a top heading, propped approximately to the level of the springing of the arch for a horseshoe tunnel. This heading was then extended to each side to permit construction of the upper part of the arch, which was extended by underpinning, working from side headings. The system was only practicable where rock loads were not heavy.

The first sizeable tunnel in soft ground was the Tronquoy tunnel on the St Quentin canal in France in 1803, where the method of construction, based on the use of successive headings to construct sections of the arch starting from the footing, was a forerunner to the German system described above.

Road headers

CUT & COVER METHOD The principal problem to be solved in connection

with this construction method is to how to maintain surface traffic, with the least disturbance during the construction period. One method is to restrict traffic to a reduced street width, another to direct traffic to a bypassing street.

Another way of supporting the sidewalls of open trenches is to substitute sheet-pile walls by concrete curtain walls cast under bentonite slurry (ICOS method), and using steel struts. This is especially a requisite in narrower streets trimmed with old sensitive buildings with their foundation plane well above the bottom level of the pit. This type of trench wall becomes a requirement for maintenance of surface traffic due to the anticipation of vibration effects potentially harmful to the stability of buildings with foundations lying on cohesion less soils.

DRILL AND BLAST

1.Before the advent of tunnel boring machines, drilling and blasting was the only economical way of excavating long tunnels through hard rock, where digging is not possible.

2.Even today, the method is still used in the construction of tunnels.

http://en.wikipedia.org/wiki/Tunnel_boring_machine

http://en.wikipedia.org/wiki/Tunnel

HOW DRILL AND BLAST IS BEING DONE.

Mechanical Drilling and Cutting-Crushing Strength of rock

TBMVarious size Tunnel Boring Machines(TBM) are used

for drilling a vast type of tunnels .

Transportation of muck , supporting and all other actions are done automatically.

Very useful in boring tunnel where all other methods fail.

A main method in use in now a days.

FULL FACE SLURRY TBM in South Africa

IMMERSED TUNNELS• THESE AREA PARTLY OR WHOLLY

ARE UNDERWATWER

• THEY DO NOT BLOCK THE ROUTE FOR SHIPS

• HENCE NO PROBLEM OF CONGESSION OF TRAFFIC AS IN CASE OF BRIDGES OVER RIVERS OR SEAS

TUNNEL JACKING• IT IS A PROCESS TO MAKE TUNNELS

IN ALREADY EXISTING BODIES SUCH AS ROADS ,RAILWAYS

• IN THIS METHOD ESPECIALLY MADE PIPES ARE PUSHED BY A HYDRAULIC RAM IN GROUND

• MAXIMUM DIAMETER OF TUNNEL BY THIS METHOD IS AROUND 2.4 METER

The choice of tunneling method may be dictated by :-

Geological And Hydrological ConditionsCross-section And Length Of Continuous TunnelLocal Experience And Time/Cost Considerations Limits Of Surface DisturbanceTunnel Methods Required Speed Of ConstructionShape Of TunnelManaging The Risk Of Variations In Ground Quality

THE OTHER SIDE Beside of many security measures , tunnelling is still

not fool proof.

Failure of automatic system will cause deadly results as depicted in Hollywood flick Die Hard 4.0.

High cost than bridges, but more fruitful from previous.

Drill-and-Blast Method1. A number of holes are

drilled into the rock2. They are then filled with

explosives3. Detonating the explosive

causes the rock to collapse4. Rubble is removed and the

new tunnel surface is reinforced

5. Repeating these steps will eventually create a tunnel

The positions and depths of the holes and the amount of explosive in each hole are determined by a carefully constructed pattern

Together with the correct timing of the individual explosions, will guarantee that the tunnel will have an approximately circular cross-section

• The machine, known as Jumbo tunneling machine

• Used to drill and form holes inside the tunnel for placing of explosive

• Machine is computer controlled and can drill 3 holes at the same time with direction or angle precisely set

Principle :-

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.

Tunnel Construction using New Austrian Tunnel Method

A trial tunnel section being formed

Tunnel Construction using Drill-and-Blast Method

• 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 Construction using Drill-and-Blast Method

A trial section of tunnel excavation making use of the concept of New Austrian Tunnel Method

Tunnel Construction using New Austrian Tunnel Method

Tunnel Construction using Tunnel Boring Machine (TBM)

The tunnel boring machine for the forming of the 3.8m diameter tunnel tube on Butterfly Valley side.


• Close up of the cutter head. • The cutting disc can cut into

hard rock and the granulated spoils will be collected and removed by a conveyor system that is positioned immediate at the back of the cutting head.


Soil disposal wagons at the disposal area on Butterfly Valley side portal. The spoil will be kept at this location waiting for the removal off-site by dumping vehicles.


Arrangement of the portal as viewed from the tunnel exit. The spoil disposalarea is located on the right side of the exit with rail track heading to thatdirection. Rail track on the left is the depot and servicing centre for the soildisposal wagons, as well as for general loading and unloading purposes.


A view of the tunnel interior with the partly formed lining, tunnel supporting girders, rail track for soil disposing wagon, ventilation hose and other supply pipe lines etc.


• A similar tunnel boring machine employed for the forming of a cable tunnel for the Hong Kong Electric on the Hong Kong Island side.

• Observe the hydraulic jack systems behind the cutter head that enable the machine to stabilize itself, pushing forward, or even slight adjustment of its heading direction.



The working principle of the mixed-ground earth pressure balanced tunneling machine under the open mode and earth pressure balanced mode.




The cutter head isbeing connected tothe shield of theEPBM by the helpof a track-mountedgantry cranepositioned on theground level. Therows of steel tubeson the backgroundare lateral supportused to stabilize the25m deep tunnelshaft.

Tunnel Construction using Cut-and-Cover MethodLarge amount of cut-and-cover tunnels were constructed in theMTR Tseung Kwan O Line in the reclaimed land of TKO New Town

Tunnel Construction using Cut-and-Cover Method

Cut-and-cover tunnel constructed in difficult environment

Tunnel Construction using Cut-and-Cover MethodBox-section tunnel tube constructed inside the tunnel trench using a set of traveling-type tunnel formwork

Tunnel Construction using Immersed TubesWestern Harbour Crossing is constructed using precast oncrete immersed tube sections. A total of 12 sections have been used, each measures 113m x 33.5m x 8.5m high and weighs about 35,000 tons. The photo shows one of the 3 batches of immersed tubes being formed in the casting yard at Shek O, HK

Tunnel Construction using Cut-and-Cover MethodThe arrangement of the approach tunnels on West Kowloon Reclamation side. As can be seen here, the ventilation building also serves as the coupling structure to receive the first approaching immersed tube. After the tube being connected, the water embraced by the elbowing land would be filled tosecure the coupling connection and make the tube land-bound.

Tunnel Construction using Cut-and-Cover MethodThe second immersed tube being towed to the launching position for sinking and connecting onto the first tube. The first tube at this stage has already been firmly positioned at the seabed and cannot be seen on the surface.

Tunnel Construction using Cut-and-Cover Method

Touching up of the land surface after the completion of the immersed tube connection. Note also the construction of the tunnels for the Airport Railway on the right hand side of the reclaimed land.

HAMMER TUNNELING HEAD MACHINES

Operating weight – 18-45 tonsHammer/bucket combinationsHydraulic cutters and rock

breakersMucking toolsPowerful diesel engines and

electric motor: with diesel drive into the tunnel and at the tunnel face using emission free electric motor

Conveyor belt to rapidly move back the excavated material

MUCKING & LOADINGMACHINES

Extremely versatile applicable to varied geological formations

Digging and loading machines in soft rock

As loading machines with typical drill and blasting heads

Scaling the tunnel faceInvertingPowerful loading performance

TUNNEL EXACAVATOR•Efficient and precise•Upper carriage with short tail permits large swing radius•Along with swing bucket dipperstick exhibitshigh break out forces •Turbo diesel engines •165kW diesel engines with high pump capacity allows use of powerful drill rigs

BALLAST LOADING MACHINESExcavation loading and

conveyance takes place in the same track

Slewing of conventional crawler not required

Loading capacity – 3-4 cu.m. per min

ELECTRIC & SPECIAL EXCAVATORSSalt miningRemoval of cement residues in

furnaceDemolition

HYDRAULIC CUTTINGUNITSAdjustable to resp

operating conditionsVaries from 15kW to

120kWLow noise cutting

operation, low vibration, smooth and gentle use

CUTTING DRUMS- for tree stump cutting anddust removal systems

SPECIAL MACHINESCrawler unit based road

heading machineUniversally rotating and

swivelingCutting boom cuts profiles

accuratelyFor underground

transport- quick disassembly & reassembly

TECHNICAL SPECIFICATIONS

Engineering

Tunnel boring machines123