The Channel Ch annel Tunnel Tunnel With With more than six million kilometers of highways and 240,000 kilometers of railways snaking across the United States, life above ground has h as become increasingly congested. unnels !rovide some of the last available s!ace for cars and an d trains, water and sewage, even !ower and communication lines. oday, oday, it"s safe to bore through mountains and burrow beneath oceans # but it was not always this way. way. $n fact, it took engineers thousands of years to !erfect the art of digging tunnels.
%&'(()* U(()* +%&U(()* When )ngland and -rance decided to link their two countries with a 2/mile rail tunnel beneath the )nglish %hannel, engineers were faced with a huge challenge. (ot only would they have to build one of the longest tunnels in the world they would have to convince the !ublic that !assengers would be safe in a tunnel this si1e. unnel unnel fires, like the &olland unnel unnel disaster, were common at this time. &ow did the engineers resolve this !roblem hey built an esca!e route. he %hannel unnel, also called the )uro unnel or %hunnel, actually consists of three tunnels, each 30 km long and bored in the rock below the seabed of the %hannel. wo wo of the tubes are full si1ed and accommodate rail traffic. $n between the two train tunnels is a smaller service tunnel that serves as an emergency esca!e route. here are also several cross/over !assages that allow trains to switch from one track to another. 5ust one year after the %hunnel o!ened, this engineering design was !ut to the test. hirty/one !eo!le were tra!!ed in a fire that broke out in a train coming from -rance. he design worked. )veryone was able to esca!e through the service tunnel. $t took 6ust three years for tunnel boring machines from -rance and )ngland to chew through the chalky earth and meet hundreds hun dreds of feet below the surface of the )nglish %hannel. oday, oday, trains trains roar through the tunnel at s!eeds u! to 700 miles !er hour and it"s !ossible to get from one end to the other in only 20 minutes8
%hunnel *ength / 794,240" +2 miles
Fast Facts 't the time it was being built, the %hunnel was the most ex!ensive construction !ro6ect ever conceived. $t took :27 billion to com!lete the tunnel. hat"s 900 times more ex!ensive than the cost to build the ;olden ;ate ??,
Vital Statistics *ocation@ -olkestone, )ngland, and Sangatte, -rance %om!letion Aate@ 7>>4 %ost@ :27 billion +B>,000,000,000 Cverall *ength@ 7D,D?0 feet E 30.43 km E 7.3 miles Under Sea *ength@ ? km E 24 miles Fur!ose@ Gailway Setting@ Underwater =aterials@ Steel, concrete )ngineer+s@ ransmanche *ink )ngineering -irm rains enter the tunnels at terminals located at -olkestone in the county of Hent in South/)ast )ngland and at %alais in the (ord/Fas/de/%alais region of -rance. he tunnels contain a railway system, which takes shuttle trains between the terminals at -olkestone and %alais *) S&U*) and through/trains which link with the national rail networks of -rance and ;reat
Construction he tunnels are 30 kilometers long and 0 meters a!art and were bored in the rock strata under the %hannel at an average de!th of 43 meters below the seabed. he two large tunnels +9.D meters diameter each contain a single/track railway line. he smaller service tunnel +4.? meters diameter is located between the two rail tunnels and is eIui!!ed with a wire guidance system for s!ecially designed service tunnel vehicles.
'll three tunnels are connected every 93 meters by a cross/!assage, which gives access to the service tunnel in case of emergency. he cross/!assages are also used for ventilation and maintenance service access. )very 200 meters, the two rail tunnels are linked by !iston relief ducts. hese are used for the regulation of the air !ressure in the tunnels. 'll three tunnels are lined with concrete linings.
Geology & Surveying UK FRANCE Shakespeare Cliff / Sangatte
Undersea crossovers E rock strata / chalk E chalk marl E gault clay de!th beneath seabed / average 23 /43 meters Satellite data from geo!hysical surveys !rovided information about the geology and hel!ed to determine the alignment and route of the tunnel. o maximi1e the favourable ground conditions, the tunnels were excavated in the layer of chalk marl exce!t for a /kilometer section on the -rench side.
Construction Sites Sangate - Construction Site In France
$n 7>?9, construction of the %hannel unnel began in -rance at Sangatte on the (ord/Fas de %alais coastline at a location 6ust over kilometers away from the -rench terminal site at %oIuelles. ' circular access shaft, 90 meters dee! and 33 meters in diameter was excavated and lined with concrete. ' hangar /like shed was built to shelter the shaft in the centre of the large construction site, which also contained offices and a lining segment manufacturing factory 'll materials, workers and eIui!ment were lowered down the shaft to the working !latform at 49 meters, where the tunnel boring machines +<= could be assembled in dry conditions. -rom this !oint, three machines excavated the undersea rail tunnels and service tunnel beneath the seabed towards Hent and two boring machines began the drive underground and inland towards the terminal site. Cne of these machines was then re/assembled to excavate the second running tunnel, thus using only 3 machines on the -rench side. ;antry cranes with !ulleys were used to lower the <= sections and subseIuently the concrete lining segments.
Cnce tunneling began, construction trains with a variety of wagons were used to trans!ort the linings, the s!oil and the workers. ' railway control room at the to! of the shaft regulated the movements of all the construction trains. 't the base of the shaft, a s!oil treatment !lant mixed the waste rock with water before !um!ing it 300 meter to the dis!osal site at -ond Fignon. Cnce construction work was com!lete, the Sangatte shaft was transformed into a !ermanent feature of the tunnel system, housing the ventilation and cooling system installations. he rest of the construction site has been landsca!ed and rehabilitation work continues with environmental monitoring of the -ond Fignon site. Shakespeare Cliff - Construction Site In Great Britain
%onstruction work began on the 94. he earlier tunnel workings were used as one of the two access shafts to the underground workings, with a rack and !inion railway used to convey eIui!ment and materials to the marshalling area underground. he six <=s were each assembled in a large cavern area, over 20 meters high and eIui!!ed with overhead cranes for lifting the <= sections, which had first been excavated to accommodate the ?.D meter diameter machines. -rom this !oint under the !latform at Shakes!eare %liff, three undersea tunnels were bored towards -rance and three underground tunnels towards the terminal site at -olkestone. he service tunnel machine on both sides bored in advance of the two running tunnel machines. Frobes on the service tunnel machine !rovided advance warning of difficult ground conditions and the data obtained !rovided data on alignment and conditions for the larger tunnel drives.
Terminal Sites UK er!inal Construction
Work on the -olkestone terminal started in 7>?? with a ma6or landfill engineering !ro6ect in order to !rovide the level area needed for the railway trans!ort system. %onstraints were im!osed by the geogra!hical features / the 740/hectare site lies at the foot of the (orth Aowns chalk escar!ment and to the south, the long narrow site is bounded by the =20 motorway. he tunnel !ortals are located at a !oint to the west of %astle &ill, 6ust north of %heriton an d from this !oint the shuttle trains make their way on a loo! track to the !latform area.
he one/kilometer tunnel constructed by cut and cover method at the west end of the site to accommodate the shuttle train loo! track has two functions. $t increases the amount of s!ace available for the other essential structures and road networks and it !rovides noise !rotection for the ad6acent villages of (ewington and Feene. ' second acoustic and visual barrier between the villages and the site was erected at the start of construction work in the form of a /meter high earth bund =a6or structures include the overbridges, access ram!s and the !latforms where vehicles load into and unload from the shuttle trains.
he site chosen for the terminal at %oIuelles, near %alais, reIuired a ma6or drainage exercise and millions of tonnes of earth were s!read and com!acted to lay the foundations for the 4?0/hectare terminal com!lex. With no land constraints, the railway system stretches from the
he tunnel boring machines were s!ecially designed for excavating the chalk marl rock which geological surveys had shown to lie beneath the seabed along the !ro!osed tunnel route. he ground conditions were ex!ected to be generally favourable in the dry and stable chalk marl, exce!t for the section to be bored in the layer of u!!er chalk between Sangatte and the terminal site at %oIuelles. &owever, several factors combined to make this a uniIue challenge for the machines@ the length of the tunnel to be excavated undersea +in excess of 20 km.J the high rate of advance reIuired to meet the construction !rogramme reIuirements. Some facts and figures serve to illustrate the achievement of these machines and all the teams of workers involved in this remarkable engineering feat.
NUMBER OF DRIVES (tunnels excavated) •
72 / D undersea, D underland
NUMBER OF TBMs •
77 / D undersea, 3 underland +a -rench machine bored 2 underland tunnels
Dimension of U TBMS •
Undersea rail tunnels / dia. ?.Dm length 20.00m
•
Undersea service tunnel / Jdia. 3.Dm length 223.00m
•
Underland rail tunnels / dia. ?.92m length 23.00m
•
Underland service tunnel / dia. 3.9Dm length 223.00m
RATE OF ADVACE / best day / 93.3m best week 42?m best month 7,97>.7m Dimension of F!enc" TBMS •
Undersea rail tunnels / dia. ?.92m length 2D3.00m
•
Undersea service tunnel / dia. 3.92m length 7?.00m
•
Underland rail tunnels / dia. ?.D2m length 277.00m
•
Underland service tunnel / dia. 3.3>m length 204.00m
RATE OF ADVACE / best day / 3Dm best week 2>2.Dm best month 7,703.9m Dates o! Brea"throughs @ •
Undersea service tunnel / Aecember 7, 7>>0
•
Undersea rail tunnel north / =ay 22, 7>>7
•
Undersea rail tunnel south / 5une 2?, 7>>7
Date Tunneling Commence# @ •
Aecember 7, 7>?9
Finishe# Tunnel Diameter @ •
Gail tunnels / 9.Dm
•
Service tunnel / 4.?m
Fi$e# e%uiment he fixed eIui!ment installed after com!letion of the tunnels had to fulfill the following functions@ "# Electricit$ suppl$ for trains an% au&iliar$ e'uip!ent
he !ower reIuired for the trains and auxiliary eIui!ment is su!!lied by two !rinci!al !ower stations at each terminal and linked to the national 400 kK networks +Seaboard at Sellindge in Hent and )lectricite de -rance at *es =andarins in the (ord/Fas/de/%alais )ach network su!!lies half the reIuirement but each is ca!able of su!!lying all the !ower necessary for the whole system. (# Electricit$ suppl$ for catenaries
he catenaries su!!ly the traction !ower necessary for the shuttle trains and the through trains. he overhead !ower lines su!!ly 23 kK / one of the most !owerful 23kK catenary systems in existence. )# Control an% co!!unications s$ste!s
'll the control and communications systems are carried in three fibre/o!tic cables. hese high ca!acity cables transmit digitally all the data for rail traffic management and all the electrical and mechanical !lant in the tunnels. S!eech communications are also transmitted by cable but, in addition, there are inde!endent radio systems including@ •
concession radio
•
track/to train radio
•
shuttle internal radio
*# unnel +entilation
'll trains using the tunnels have electric traction so there is n o engine exhaust !ollution. he service tunnel vehicles have diesel engines designed to give very low emissions. 'ir is !um!ed into the service tunnel from ventilation buildings at Shakes!eare %liff and Sangatte. he service tunnel acts as the su!!ly duct for normal ventilation. 'ir handling units located above the doors of the cross/!assages every 93 meters control the flow of air from the service tunnel to the railway tunnels. ,# rainage s$ste!s
he drainage system of five !um!ing stations !ermits the removal of water from the tunnels. Water from normal see!age is directed via channels into storage tanks or sum!s at the lowest !oints and discharged by !i!eline to the !um!ing stations. .# Fire-fighting
Smoke detectors are installed in all the technical rooms located within the cross/!assages. 'utomatic extinguishing devices and remote control cut/off systems are also installed. ' dedicated water su!!ly line in the service tunnel is fed from storage tanks and !um!ing stations at the !ortals. his line feeds the fire hydrants in the cross !assages and in the running tunnels. # unnel cooling s$ste!s
he tem!erature in the tunnels is maintained at an acce!table level of 23L% by the circulation of refrigerated water in each section of tunnel via a discharge and a return !i!e. Gefrigeration !lants at the former construction sites of Shakes!eare %liff and Sangatte !rovide the chilling and circulation systems. 0# Ser+ice tunnel e'uip!ent
Cn each side of the service tunnel, technical rooms contain all the necessary electrical and technical rooms for the eIui!ment reIuirements in the service tunnel. he %hannel unnel rans!ortation System he %hannel unnel !rovides a railway link between the road and rail networks in ;reat
S'(TT)E TRA*S FOR ROAD VE'*C)ES Goad vehicles access the terminals from the =20 motorway in Hent or via the autoroutes '7D and '2D in the (ord/Fas/de/%alais. %ars, coaches and lorries are directed into a!!ro!riate lanes before arrival at the tollbooths, where tickets are !urchased. *orries follow a se!arate route to areas where travel facilities and customs clearance for freight are located, before following signs to the loading !latforms. Arivers of !assenger vehicles may visit the !assenger terminal buildings for refreshments or sho!!ing facilities or they may !roceed directly towards the allocation 1ones where signs indicate a designated loading !latform. Kehicles then travel onto the overbridges and down the ram! to the !latform and into the shuttle train.
5ourney time !latform to !latform is 3 minutes. he *) S&U*) vehicle trans!ort service is owned and o!erated by )urotunnel &GCU;& G'$(S -CG F'SS)(;)GS '(A -G)$;& &igh/s!eed trains offer !assenger services between the international stations of *ondon Waterloo, Faris ;are du (ord and
)urostar rains
Fower out!ut@
3.9D =W or 9D00h!
*ength of locomotive@
22.273m +92.3 ft
Weight of locomotive@EAJ
72 tonnes
*ength of rain@
m +72>2ft D? tonnes
Weight of train@
2000 tonnes
Weight of locomotive@
=ax. S!eed@
7D0kmEh +700m!h
Weight of train@
?00 tonnes
(ormal S!eed@
740kmEh +?9m!h
rack gauge@
7.43m +3D.3 in
Wheel diameter@
7.230m +4> in
=aximum o!erating 00kmEh +7?3 s!eed@ m!h +-rance
