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Terra Solutions
Our contribution to high speed trains
Our contribution to high speed trains Our contribution to high speed trains


Terra Solutions - Technical Corner - Case studies - Our contribution to high speed trains

Since 2008, MAXAM is part of the engineer challenge AVE route, that after linking Madrid and Barcelona, today continues towards the Spanish-French border.

With 2.3 million travellers in its first year of operation, the Madrid-Barcelona AVE has elevated rail transport to a different level. Since the 20th of February 2008, the two Spanish capitals are connected in 2.38 hours with direct trains that reach an average speed of 240 km/h. Today, a new phase is being carried out in this large work of infrastructure: the route that links Barcelona with the French border with the Sarrià de Ter-Sant Julià de Ramis, Vilademuls- Pontós, and Borrassà-Figueres stretches in between.

Environmentally respectful
In this new stage, new challenges in the form of tunnels have been projected. Challenges in which MAXAM provides the best solutions to overcome the difficult landscape present across North-eastern Spain and the Pyrenees border.

The Company offers a wide range of civil explosives and initiation systems, backed up by its professionals’ technical expertise that help beat the difficulties of the land’s orography with the utmost respect for the environment and a strict corporate safety policy when handling, transporting and delivering our products. In this project, MAXAM works with three other companies with a wide experience in tunnels construction, PROACON, FCC and CAVOSA that work in three itineraries of the Barcelona Sants-Figueres route in the Girona province.

The Sarrià de Ter-Sant Julià de Ramis stretch
MAXAM helps its clients beyond simply offering its products for blasting activities-, to prepare and follow-up vibration monitoring reports, with training courses for artillerymen, etc. In this first stretch of the route, there are two tunnels that deserve a special mention since they’re going to be executed using the mine excavation system.

The first one, called the Sarrià tunnel, is an extension of the Girona II tunnel. Works are expecting the construction of 3.042 m with a section of 114 m2 to form a single underground structure with a total length of 4.606 m. The second stretch, called the Montagut tunnel, is 475 metres long with a projected section of 140 m2. Running parallel to the tunnel, three wells and an access gallery to the Sarrià tunnel are being excavated using drilling and blasting methods. The gallery will serve as a dividing element for future works. All the explosives used are being supplied by MAXAM, who also offers technical advice and support in environmental studies, mainly in vibration related aspects.

In preparation to build Montagut’s tunnel, excavation using explosives was necessary: 120.000 m3 at the north entrance and around 60.000 m3 at the south entrance. RIODIN, RIOGEL TRONER or NAGOLITA explosive charges were used, depending on the existence or not of water in the shot holes. The maximum operating charge (CIMO), i.e. the number of kilograms of explosive that detonate at the same time in the blast’s shot sequence, was limited to 15kg for environmental reasons. This limit guarantees that vibration keeps to a much lower level than the maximum allowed following the risk prevention criteria.

When it comes to the excavation itself, the Tunnel’s Manager and mining engineer, Jonathan González García, points out that the works to advance began on the 7th of January with an expected period of execution of twelve months. Blasting in three different fronts is currently taking place: at the north entrance of Sarrià, at the intermediate gallery and at the south entrance of Montagut. The explosives used are: Nagolita, with Anfo pneumatic charges, and RIODIN. The detonators used are of the RIODET range, electric with a high sensibility. In this stretch, PROACON has valued very positively the service provided by MAXAM’s explosives that help keep to the executing time deadlines.

The Vilademuls-Pontòs section
Here, the route has three viaducts and a tunnel. Half the section will go underground through the Les Cavorques tunnel, in a mine, with a total length of 2.939 metres. “In the initial tunnel project, despite the fact that any excavation method could be used, the need to use explosives wasn’t very evident”, Francisco Pérez Lira, Tunnel Manager and Head of Production explains. However, they decided to request the use of explosives because they had MAXAM’s technical team’s total support. The Les Cavorques tunnel is a clear example of how compatible the excavation method by means of drilling and blasting is with an initiating mechanism, when the terrain demands it.

As we advance, we encounter conglomerates that need to be blasted. Sometimes they appear throughout the section and therefore a complete shot plan can be drilled. In these cases, four metres of advance in one shot have been reached.

However, it’s more normal to have to adapt the shot plan to the rocks’ shape as we advance. The rest of the softer material is extracted using mechanical methods. The presence of clay in the ground makes supporting the inside of the tunnel of vital importance. So, a metallic structure with “elephant legs” (reinforcement in the legs of the structure) is placed to achieve a better support, and a high resistance cement 35 cm thick is projected. In some cases, cylinders that are 12 metres deep are used to fight the grounds’ strong convergences. In this stretch, explosives are left mainly for the north entrance of the tunnel. The shots are being sequenced with RIONEL non electric detonators. Thanks to everybody’s effort, dedication and organisation skills, an average of 211 metres per month are reached in the mechanical starting system, and 150 metres a month in the mixed option (mechanical and blasting). The Tunnel Manager and Head of Production highlights the record ten metres reached in one single day, specially taking into account the need to support the terrain and the time this requires.

The Borrassà-Figueres section
Finally, the Borrassà-Figueres section has five viaducts, two permeability structures, a tunnel and the taking over and stationing of trains post of Figueres. The Mining Technical Engineer, Joaquín González Meleiro, CAVOSA’s Tunnel Manager, highlights MAXAM’s contribution to train artillerymen and the company’s punctuality in delivering the explosives.

As for the tunnel, González Meleiro explains that approximately 50% of its 1.720 metres go through pleated and karstificated limestone, so it will be executed with drilling and blasting techniques and the rest by means of mechanical methods. Along the stretch excavated using explosive, Joaquín González Meleiro highlights that in some cases they are advancing 4.5 metres per day in the north entrance, given the tunnel’s high demand for support. Given the rock’s characteristics, the explosives used to advance are RIODIN (32x200mm) and the RIOGEL TRONER (32x500). The latter is not very common, but has been chosen given the landscape’s features. The detonators used are electrical, with a high insensibility, called RIODET.

Committed to society
The tunnels being built as part of this large project reflect the great effort being put into achieving an environmental respectful objective when faced with the construction of a very large infrastructure in the beautiful surroundings of the Alto Ampurdá region. To achieve this, MAXAM and its team of professionals are presenting solutions to all the obstacles found in these terrains. As part of MAXAM’s commitment to society, the Company is present in these construction works to offer the highest quality to a first class service like the high speed railway transport.

Our special thanks to: Jonathan González García, Manager of the Sarrià de Ter-Sant Tunnel Section; Julià de Ramis; Francisco Javier Pérez Lira, Tunnel Manager- Head of Production of the Vilademuls-Pontòs Tunnel Section; and Joaquin Gonzalez Meleiro, Tunnel Manager from CAVOSA for the Borrassà-Figueres Section.


Last update 2019.08.08
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