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All aboard the Spanish main

High speed rail

Spain's second high speed rail line is nearing Barcelona, with tunnels and viaducts needed all along the way.

Services are the bane of Necso contract manager Alfonso Ranninger's life. Services large and small, pipes, cables and ducts by the dozen.

Shifting them, avoiding them, replacing them and repairing them is only half the problem;

waiting for the utilities to deal with them also disrupts his carefully worked out earthmoving programme.

Ranninger is responsible for construction of a 12km long section of the new high speed rail line from Madrid to Barcelona, one of nine contracts in the latest section under way between Lleida and Martorell. A few kilometres beyond that is Barcelona.

Schedules are tight because railway infrastructure company Gestor de Infrastructuras Ferrovarias (GIF) wants to see the line operational right into the Catalan capital by 2004. Beginning last January the contractor has just 18 months to finish the civils work.

In almost all the sections in this hilly region there is extensive tunnel, bridge and embankment work. Necso's contract includes a 1,280m long tunnel, a 646m long viaduct river crossing and major embankments. The tunnel is going reasonably well and piling for the viaduct is in progress.

So too is the 990,000m 3ofearthmoving for the embankment and 638,000m 3of cutting.

But this is where the services interfere. Necso's section runs past the coastal town of Tarragon which has a major oil refinery and a series of downstream plastics and petrochemical works around it. Oil pipes, gas pipes, cooling water ducts and power lines criss-cross the area.

'We have eight high voltage lines crossing the route including a 440KV line, the highest voltage in Spain, ' says Ranninger.

'Big pipelines also have to be moved or be ducted below the embankment.

'But then we also have lots of small pipes to deal with, ' he adds. Most of the line is in rural land which, typically for Spain, has numerous irrigation pipes feeding the small farms. These have to be removed and restored after works.

'It is more like the work of Chinese peasants, ' says Ranninger. 'It's small scale and not expensive but it takes time.'

His concern with otherwise relatively straightforward earthmoving is to keep the big plant items moving. He uses subcontracted teams, each with one Caterpillar 375 excavator loading into three Cat 777 trucks.

Lifts of 250mm for the embankments are spread with Caterpillar D8 dozers and compacted using sheepsfoot compactors.

'You must have a programme for such big pieces of equipment.

And that's the problem, ' says Ranninger. 'Locating services and, more importantly, waiting for the bureaucratic procedures to churn through before the utility can move them, can be frustrating.'

Despite that, he believes work is going well. It is, however some of the most stringently controlled and instrumented that he has experienced. Quality standards must match ISO 9001.

At the north end of the contract the tunnel is well under way, in two sections. First is 325m of 'false tunnel' - a well tried cut and cover method using a concrete arched horseshoe shell cast at the bottom of a battered trench and later backfilled.

This runs into a full bore tunnel 955m long through a 65m high hill comprising limestone, sandstone and predominantly mudstone. Necso is using a Paurat T2.13 roadheader for the two headings. Progress has been about 8m a day, with 475m achieved from 5 May to 14 July.

'The tunnel cross section has a 7.48m radius at the top and 6.68m below, ' Ranninger says.

'It needs such a large - 140m 2-cross section to cope with 350k/h trains and the pressure waves they generate.'

The roadheader works in an unusual configuration, to one side of the tunnel, with a Komatsu 320 loader pushing up alongside it at the face to remove spoil as the work progresses.

This is loaded onto road trucks, running on a well prepared temporary tunnel base road surface.

'We were lucky too' says Ranninger, 'because alongside our tunnel is an old and now disused railway tunnel. We put in lights, lifted the rails and used it as a haul road.' Spanish railways company Renfe was co-operative, but insisted that Necso reinstate the track once the new tunnel is finished.

Tunnelling is a sub NATM method using four categories of support according to rock conditions. These range from a 50mm layer of sprayed concrete over steel arches at 1.4m centres and 4m long passive anchors, to steel arches at 0.4m centres and 320mm of sprayed concrete.

Further along the contract preparations are beginning for the big viaduct. This is to be a push launched concrete box structure on 16 - up to 40m highpiers to span a river valley.

The tiny trickle of water around the big piling rig working in the river bed hardly seems to justify such a massive structure but sudden storms in September can turn the river into a torrent.

Piles will be some of the biggest in Spain with up to 2m diameters dropping to 30m depths through the gravels and sand of the valley to clay beneath. A steel casing is used for the first 12m.

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