Construction of Access Adits Underway on Lyon-Turin High Speed Line First envisaged in 1990 as a mere extension of the high speed passenger network between France and Italy, the Lyon-Turin rail link is today a strong sustainable and ecological response to freight transport needs. The goal is to dig a railway beneath the Alps, between Saint-Jean-de-Maurienne in France, at an altitude of 570 metres, climbing to 752 metres and ending at 580 metres in Susa valley in Italy. The route will therefore pass under Alpine peaks shaping a sort of circumflex with gradients never exceeding 12.5‰. This very flat path will allow freight trains pulled by a unique locomotive to run at cruise speed while trains on old tracks travel much higher under the mountains and require two or three locos. Two other tunnels under the Chartreuse and Belledonne massifs in France and other tunnels in Italy will supplement the Lyon-Turin cross-border tunnel. In Italy, the route is being reviewed further to massive demonstrations against the project in Susa valley in 2005 due to worries about uranium and asbestos in the mountainside.Ecological urgencyThe two- or four-lane road tunnels built from the 1960s to the 1980s (Mont-Blanc, Frejus, Grand Saint-Bernard, Gotthard, San Bernardino, Brenner, Tauern) have favoured a real boom of freight transport by road. Not less than 154 million tonnes of goods was carried in the Alps in 2006 for just 70 million tonnes in 1984. There are 9,800 trucks crossing the French-Italian border each day. By 2020, it is estimated that 1.5 million more trucks will cross the border each year.The reviewed project submitted by Italy in July is now under analysis by the EU in Brussels and the outcome is awaited by the end of November. The tunnel will be built but its construction could be much delayed. A new route running more to the south of the initial alighment would shorten the base tunnel between France and Italy from 52.7 to 51.5 km, returning to the surface in Chiomonte instead of Venaus, the valley that became the symbol of the resistance to the high speed rail link in Italy. Visit www.notav.itFinancingThe Lyon-Turin rail link forms part of the priority projects within the trans-European network endorsed by the European Council in Essen in 1994. This 65,000 km-long complex network requires thirty railway hubs budgeted at billions of euros. As part of the programme, the countries in charge of the construction are entitled to request European funds to finance up to 30% of the total cost. But they need to act rapidly. The European Commission has earmarked EUR8 billion for the 2007-2013 period but the number of projects exceeds the possible financing capacity. Under pressure to act due to the budgetary calendar, France and Italy requested EUR725 million for that period. Click here. The Lyon-Turin scheme including all the structures between the two cities is estimated at EUR12.5 billion. The cost estimate for the cross-border section, in other words the base tunnel, is EUR7.6 billion, financed in majority by Italy (63%) and the remainder (37%) by France while less that 10 kilometres of the approx. 52 km base tunnel is located in Italy, the very major part of it being on the French territory.Preliminary works prior to construction of the base tunnelThe bi-national company Lyon Turin Ferroviaire (LTF) is the project owner. It was established on 3rd October, 2001 by Réseau Ferré de France (RFF) and Rete Ferroviaria Italiana (RFI), at the request of the French and Italian governments, following the international agreement signed in Turin on 29th January, 2001, to carry out the preliminary studies and preparatory works of the French-Italian section, i.e. the 52.7 km cross-border tunnel between Saint-Jean-de-Maurienne and Bussoleno. Click here, fr/11 & it/80. Read E-News Weekly 27/2007, 15/2007, 7/2007, 1/2007, 2/2006, 50/2005, 46/2005 & 34/2005. Visit www.ltf-sas.com, www.transalpine.com and www.transpadana.orgThe first works are underway in France to build three access adits located, from west to east, in Saint-Martin-la-Porte, La Praz and Modane–Villarodin-Bourget. These are intermediate attacks to access to the base tunnel of the future Lyon-Turin high speed rail link. The technical objective is to know better the ground and to use these steep sloping tunnels as service and rescue access.Once the axis of the future base tunnel is reached, it is planned to bore exploratory tunnels along the alignment. These tunnels are being reviewed and will be put out to tender since they do not form part of the ongoing contracts. The original project envisaged a 2 km west tunnel and a 1.8 km east tunnel in Saint-Martin-la-Porte, a 2 km west tunnel in La Praz, and a 900 m west tunnel and a 2,050 m east tunnel in Modane–Villarodin-Bourget.On the Italian side, the construction of the Venaus exploratory tunnel has been cancelled because of continual protests from local communities in Susa valley.Complex geology and hydrogeologyTo prepare the jobsite, as early as 1990, scientists and geologists of France's geological and mining research bureau (BRGM), the Grenoble and Chambéry universities, the university of Turin in partnership with SEA Consulting, and the Turin polytechnic university analysed and mapped the site to give engineers the best possible geological and hydrogeological map and a description of the rocks in accordance with their relevant parameters for tunnelling. These specialists identified not less than 25 rock types, affected by three levels of fracturation producing 75 possible scenarii. A real patchwork. This is why there is a financing margin, equal to 12% of the EUR7.6 billion planned for the international section of the project, i.e. the base tunnel. Visit www.brgm.fr, www.polito.it, www.dst.unito.it and www.seaconsult.euAnother problem is pressure that may cause violent decompression phenomena. Squeezing ground cause the tunnel to shrink. Ultimately, a further enemy is water. The deeper tunnellers work, the less water they encounter but its pressure is higher.Faced with such challenges, the geologists performed more than 150 bore holes, 50 m to 1.6 km long, taking samples vertically, horizontally and diagonally within the axis of the future tunnel, for a total length of 55 kilometres. They even took two oil drill-type samples, much more expensive but more informative.Then, not only they produced foreseeable geological sections but also 3D models of the subsoil of certain areas estimating the probability in terms of rock type and geometry of the geological formations. This mapping in volume was necessary for two reasons: first, the dimension of the project with two parallel bores and secondly, its complexity at the foot of the Modane adit where a network of secondary tracks, and a rescue and medical centre will be installed.The Saint-Martin-la-Porte access aditSince March 2003, the Saint-Martin-la-Porte access adit is being built by a joint venture of Razel, its parent company Bilfinger Berger, Pizzarotti and Granulats Rhône-Alpes (GRA). The contract is worth EUR40.4 million. A joint venture of Egis (ex Scetauroute), Antea and Alpina is the construction manager. Visit www.razel.fr, www.bilfinger.de, www.pizzarotti.it, www.egis.fr, www.antea-ingenierie.fr and www.alpina-spa.itThe same builders recently pocketed a EUR72 million contract to continue and finish the adit. The works mostly include approx. 780 m of tunnel, cross section of 112 sq m, and associated structures and core drilling. The same joint venture of consultants concluded a EUR3.1 million deal for construction management.The 2,280 m-long single bore adit features a 13.40 m external diameter, a 9 m finished internal diameter and a 6.45 m net width. Some service niches, 15 m x 6 m, will also be provided.In the first 800 metres, the geology was sandstone of good and excellent quality, then crews gradually entered in the Encombres coal-bearing formation where considerable convergence problems appeared. There has never been water or methane gas. The rock mass is extremely chaotic, with variable percentages of argillite, coal, sandstone and grey schists, black schists, cataclasite and psammitic sandstone. However, the GSI (Geological Strength Index) is not subject to important variations, its average value being 38. The overburden in this varied zone ranges from 250 to 600 m.As of 18th July, 2007 tunnelling had reached chainage 1,600 m and as of 9th October, 2007 crews had reached chainage 1,651 m. The executive project is prepared by the builders and submitted to the construction managers for approval. The construction managers are assisted both by their own experts and by outside consultants of international reputation. At the site, the engineers are verifying if slight alterations to the construction phases may optimize the works.In the first 800 metres, the drill/blast method was adopted, using a three-boom Atlas Copco Rocket Boomer XL3 C and explosives. The daily progress achieved was 0.5 metre. The support consisted of self-drilling anchors, glass-fibre rods at the face, Swellex bolts, normal steel and sliding steel arches, shotcrete reinforced with Dramix fibres, and deformable fibre-reinforced concrete plates. Visit www.bekaert.comOn the construction managers’ recommendation, and in agreement with LTF and the joint venture of builders, it was decided to change the construction method from chainage 1,250 onwards, because of the substantial convergence, and the type of cross-section. From then on, a Caterpillar excavator equipped with hammer or other tool has been used.Initially, it is was planned to excavate a horseshoe-shaped cross-section at Saint-Martin-la-Porte. This has been subject to several alterations until the third change adopted in the stretch of the adit submitted to substantial convergence, from chainage 1,250 to chainage 1,384. In this stretch, a horseshoe-shaped cross-section was planned together with a yielding support and reinforcement of the nucleus ahead of the face and the crown. The support consists of yielding steel arches TH 44/58 every metre, 24 self-drilling bolts of 8 m in length at the top heading and benches, 10 self-drilling bolts of 8 m in length at the invert, eight Swellex bolts Mn12 of 4 m at the top heading, 8 mm-diameter welded mesh, 150 x 150 mm nets, and 20 cm fibre-reinforced shotcrete. The consolidation is carried out by means of 54 glass-fibre rods supplied by Elas Geotecnica, 15 m in length, and minimum lap of 6 m, and 20 self-drilling injection bolts of 8 m at the crown. Visit www.swellex.com and www.elasgeotecnica.itAfter chainage 1,384, another type of cross-section has been decided, which changed also the type of support and consolidation adopted until then. The cross-section is polycentric (almost circular). The consolidation of the ground nucleus ahead of the face requires a greater number of glass-fibre rods (121) compared to the previous cross-section. The rods are installed so as to form a reinforcement ring around the contour of the excavation. Advance is carried out in three phases.During phase 1, crews install yielding steel arches TH 44/58 every metre, 10 cm-thick fibre-reinforced shotcrete, 32 self-drilling bolts of 8 m in length all around the contour of the excavation, as well as eight Swellex bolts Mn12 of 4 m in length. Phase 2, implemented at a distance of about 15 metres behind the tunnel face, consists in installing a more robust support made of 20 cm-thick fibre-reinforced shotcrete, flexible steel arches and HIDCON (high deformable concrete) elements. The scope is to allow for a deformable behaviour of the excavation under controlled conditions. In phase 3, at a certain distance from the tunnel face, the invert is dug and cast with in situ concrete, then the final concrete lining is poured all around the excavation. The most important and innovative feature is the use of high deformable concrete (HIDCON) elements able to absorb a deformation of 45-50% and to guarantee a uniform axial load, which translates in a confinement action around the contour of the tunnel. These elements are installed at the junctions of the yielding steel arches. Initially, eight elements (four on each side) have been installed at the walls and top heading. From chainage 1,450, a further deformable element has been installed at the centre of the invert.Given the geometry of the steel arches, the maximum acceptable convergence during phase 2 is 600 mm. If such figure is reached before passing to phase 2, a reprofiling of the tunnel is performed. Consolidation tasks are extended horizontally to all of the tunnel face and around the contour at the top heading and benches. The deformability of the cross-section in phase 2 tolerates a further convergence of about 400 mm.The means used or still in use include an Atlas Copco XL3 C drill rig, two Atlas Copco Boltec 435H bolting machines, a Caterpillar 325 LN excavator, a Kobelco excavator, a Casagrande X driller for drilling the glass-fibre holes, a Volvo LC 220 loader, two Normet Spraymec 9150 WPC shotcreting robots, a Normet Himec 9810 B HEX lift platform to install the steel arches, a Merlo elevator platform, three to four Volvo A25D dumpers and four Dieci F7000 concrete mixers. View pictures here. Visit www.atlascopco.it or www.boomer-rig.com, www.cat.com, www.casagrandegroup.com, www.volvo.com/constructionequipment, www.normet.fi, www.merlo.com and www.dieci.comFor spoil haulage, a conveyor belt has been used in the first 1,200 metres then dumpers. Visit www.magazine.bilfinger.com to read more. Atlas Copco's Rocket Boomer L2 C and Normet's Himec in Modane, September 2007 The La Praz access aditThe La Praz access adit, commenced at 974 metres in November 2005, is built by a joint venture of Spie Batignolles TPCI, Sotrabas, Ghella and Cogeis. The foreseen amount of the contract (VAT not included) is EUR61.5 million for a time frame of 36 months. The project manager is SPI (Schmidhalter & Pfammater Ingenieure). Visit www.spiebatignolles.fr, www.ghella.com, www.cogeis.it and www.spi.chThe subcontractors are Fondazioni Speciali and GD Test for the bore holes, probe drilling and special works, Technoscavi for mucking-out inside the tunnel (every day of the week) and Casarin et Fils for installations, concrete transport and mucking-out outside the tunnel (every day except on week ends). Visit www.fondazioni-speciali.com, www.gdtest.it and www.technoscavi.itThe La Praz access adit is a 2,572 m-long 80 sq m cross sectional tunnel, with a gradient of about 8%. In a first stage, the adit will serve for access to the international base tunnel and in a second stage for access to rescue vehicles.The drill/blast method is employed. The dynamite has been replaced this year by Nitro Bickford’s MORSE system, an explosive of new generation composed of two inert pastes that can be easily brought to the face. The compounds are detonated only once mixed in the blast holes. Click here. Visit www.nitrobickford.frThe means used include two drill rigs from Atlas Copco, a three-boom WL3 C and a two-boom L2 C with basket for face bolting or as a back-up; a Liebherr 934 excavator for purging rock spalls, cleaning the invert and other tasks; a New Holland excavator; a Volvo L220E loader with side-tipping bucket to avoid U-turns in the tunnel; two Volvo A25D dump trucks with rollers under the tipper to allow U-turns in the tunnel; two Normet Spraymec concrete sprayer; two Normet Himec lift platforms, one of which is equipped with a steel arch clamp; and two Atlas Copco Boltec, one of which is equipped for resin bolts and the other for Swellex bolts. Visit www.liebherr.com and www.newholland.comThe support consists of HEB 200 steel arches supplied by LMT Arcane, HA 25 resin bolts from Mecsider, welded mesh from Bruno F.lli, Swellex bolts from Atlas Copco, sheet plates and sodium silicate concrete admixtures. Visit www.mecsider.com and www.brunofratelli.comRock samples are taken by the joint venture ahead of the face and by the subcontractors along the lateral niches. A cave-in occurred in September 2006 had to be concreted by means of an injection pump prior to being bored again.Work proceeds 24 hours seven days a week. As of mid-September 2007, 1,174 metres had been bored. As of 1st October, crews had progressed further to 1,211 metres. Visit www.descenderiedelapraz.fr Main figures Muck (adit) 225,000 cubic metres Muck (associated structures) 38,000 cubic metres Mucking-out to dump site 263,000 cubic metres Reinforcement concrete 2,500 cubic metres Shotcrete 19,800 cubic metres Concrete (concrete bed, rolled compacted concrete and invert) 14,400 cubic metres Ground injections 400 cubic metres Anchoring bolts 150,000 linear metres Glass-fibre bolts 20,000 linear metres Ground investigation 11,500 linear metres Drilling for special works 3,000 linear metres Steel arches and sheeting 1,000 tonnes Total man hours 500,000 The Modane–Villarodin-Bourget access aditThe construction of this 4 km access adit started beneath the village of Le Bourget at 1,095 metres, at the northern exit of Modane. This tunnel will provide access to the base tunnel and will be used for spoil extraction. The average excavated cross-section is 70 sq m (width of 10.50 m). At its end, the adit crosses the path of the approx. 52 km future base tunnel of the Lyon-Turin scheme at the spot of the future underground safety station. The tunnel starts from the right side of the Alpine arc to plunge deep at more than 360 metres below the mountain. Foot of the Modane access adit (widened cross-section of 115 sq m), September 2007 The construction manager is Lombardi. The construction contract, worth EUR51.4 million, has been awarded to the same joint venture as that of the Saint-Martin-la-Porte access tunnel, with the exception of GRA who has a separate contract with LTF for the production of concrete. Around 1.1 kilometre of tunnel was bored between July 2002 and May 2004 by another joint venture before their contract was cancelled. The new notice to proceed was given in September 2005. Read E-News Weekly 28/2004. Visit www.lombardi.chTerrasol is consultant on the project. The subcontractors are Fondazioni Speciali and GD Test for special works, probe drilling ahead of the face and in situ tests, Figuière for muck extraction and Casarin et Fils for civil engineering works. Visit www.terrasol.comThe adit mainly crosses the Briançon siliceous zone of Vanoise, mostly composed of quartzite and micaschists with some anhydrite. There was water infiltration mainly in the first 900 metres of the adit when crossing rauhwackes with presence of water (up to 120 l/s) at the main contact zones between the rauhwackes and quartzites. The residual flow of this water ingress is now about 30 l/s. There is no convergence in Modane. Probe drilling to take core samples on lengths of 150 to 200 metres in the axis of the tunnel are undertaken from the side niches to avoid any disruption to the excavation cycle.Atlas Copco has supplied a three-boom Rocket Boomer WL3 C, a two-boom Rocket Boomer L2 C, a Boltec LC and a Diamec U6. Here again like in La Praz, the dynamite has been replaced in July 2006 by the MORSE method of Nitro Bickford.Normet has supplied a Spraymec 9150 WP shotcreter, a Himec 9910 B REX lift platform to charge the explosives and a Himec 9915 BA 1 to install heavy 1.5-tonne steel arches.The rock is hauled away by a fleet of 7 to 10 Volvo dumpers.The worksite is busy 24 hours in three shifts, seven days a week. As of 4th October, 2007, excavation had progressed 3,930 metres. This adit, which is the longest of the three in the French Alps, will be the first to be completed, in November 2007 except unexpected events. Visit www.ltf-sas.com/upload/File/depliantmodane2007light.pdf MS mobile water treatment plant at La Praz Nitro Bickford’s MORSE systemMORSE, a French acronym meaning Module for Repumping and Sensitization of Emulsion, is a technique by which a bulk explosive insensitive to water can be pumped to optimally fill the blast holes while reducing transport and storage of explosives and improving site safety because the quantities of explosives handled are reduced to a minimum. It is the safest and most efficient system for underground blasting. The process can activate an emulsion, a very efficient explosive, at the very site. It limits the quantity of explosive in the module to 50 grammes. The explosive is pumping into the blast holes. The emulsion fills completely the holes and optimizes the drilling pattern. The MORSE module is suitable for all types of carriers or mining vehicles. To know more about the MORSE method, click on Nitro Bickford's logo or read (in French) the description of the method at www.nitrobickford.fr/IMG/pdf/MORSE.pdfSpoil managementA spoil processing plant has been installed at Modane to recycle some of the materials excavated from the three tunnels and produce concrete aggregates used for the projects. This processing phase is being optimised with a view to preparing the base tunnel worksite, which will generate about 14.7 million cubic metres of spoil, 40% of which approximately could be recycled into concrete aggregates (about 25%) or used for embankments, earthwork and landscaping (about 15%). In Modane, the excavated material account for one million tonnes, whereof 300,000 tonnes to transform into concrete aggregates and 700,000 tonnes to haul away to final dump sites, equivalent to a volume of 400,000 cubic metres.Water purification at La Praz and ModaneCrews working in the La Praz and Modane adits are faced with the presence of water while there is no water in Saint-Martin-la-Porte. In Modane, all the waters are conveyed to a settling and treatment basin prior to being discharged in the Arc, a river bordering the site. The water released in the river is subject to periodic measurements to monitor certain parameters and make sure that the contents do not exceed the limits set by the administrative authorities.At the two sites, MS has supplied complete units to eliminate gravels and sands in line with the surface water conveyance. The system eliminates rapid settling sands. Indeed, after desanding, there is no sudden sedimentation risk of the extra fine particles (<63µ) contained in the waters and the wear of the pumps and pipes is therefore very reduced. To improve the safety of the system upstream of the hydrocyclones, scalping is performed beforehand using a protective trommel equipped with a 7 mm grid and a vibrating dewaterer removes water from the sands, with a capacity of up to 60 t/h. At each site, these scalping-desanding units have the appropriate size to cope with the maximum instantaneous flow of heavily loaded waters, i.e. 720 cu m/h at Modane and 270 cu m/h at La Praz. MS units are peculiar because there are modular and mobile, which means that they move as the tunnel progresses. Extra fine particles (<63µ) that cannot be processed through hydrocycloning are pumped to the surface.At La Praz, MS has also supplied a flocculant and coagulant dosage unit to improve the decantation of waters in basins and an automatic filter press to dehydrate the removed sludge. Click here to read more on MS systems. Visit www.m-s.frThe pumping of infiltration water in these two tunnels has been commissioned to CE2A. Submersible pumps are used to convey waters loaded with sands and gravels to the MS units and a set of pumps is positioned downstream to transport to the surface waters loaded only with extra fines. Their contract is worth EUR1.1 million.The main difficulties are a 360 m height difference at the Modane access adit, daily variations of the total manometric height, and waters heavily loaded with silica, laitance and clays. The installation is composed of 51 Arder pumps of a capacity of 160 kW, 20 Tsurumi submersible pumps, electric panels, pipes and hydraulic equipment. This dewatering system is capable to pump 40 litres of water/second, with capacity for up to 150 litres/second and the possibility to reinforce the capacity to 300 litres/second. Visit www.ce2a.eu/index.php?option=com_content&task=view&id=12&Itemid=54 and www.tsurumi-europe.com 43/07. For the Saint-Martin-la-Porte adit, some information is taken from presentations and reports by the Department of structural engineering (DIST) of the Turin polytechnic university, headed by Prof. Giovanni Barla, consultant for the construction manager