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Traditional tunnels

Technical advice and design missions for the Abastumani road tunnel - Georgia. 

The project involves the construction of a 368 m long tunnel with the NATM - drill and blast method. The tunnel rock mass is represented by andesite tuffs (60%) and an andesite band (40%), with medium joint. After the construction of two thirds of the tunnel, water inflow was reported and a partial rock fall of the vault had place. After the accident, the front face excavation was stopped. 
Following this event, the owner and the Construction Supervision (EGIS) asked ICF to advise on the reparation of the damage and on the safe continuation of the excavation. 
Our intervention was done in two steps; first, we advised about the reparation of the damaged section to undertake in terms of drainage, vault reinforcement and filling of cavity. For the stabilization of the bolts to put in place, calculations of rock bolts were carried out based on the UNAL formula. 
In the second step, we recommended first the additional investigations and rock tests to be done on the vault and the front face of the tunnel. Then proper calculations of the stability of the front face and the vault have been undertaken, according to the theory of Tamez, to define the new excavation method and sequence.

Bypass formwork studies lot 1 - line 16 of the Grand Paris Express.

Calculations for dimensioning of wooden formwork for the execution of the definitive layer of the tunnel connecting the shafts and the main tunnel for CIPA SARL.

Technical assistance services to the subcontractor during the execution of the works.

These are bypass excavated using the traditional method, in the presence of groundwater.

Maison Blanche. Lot GC01 of Metro Line 14 south extension. Paris 13°

Technical Direction and validation of the technical design, Contractor-Side, of the TN2 tunnel connecting "Olympiades" Station to "Maison Blanche" new station.

Redaction of the building Method Statements and validation of execution procedures. Progress Planning management.

Follow up of the works during the execution of the access shaft and the tunnel excavation works (2018-2019).

The project includes the technical design and building of the new underground station Maison Blanche, with a "top-down" sequence.

The tunnel, excavated with traditional method, is 136 m long, it is 7.62 m width, with shallow overburden (8-12 m). The mix front face is limestone at the top, plastic clay at the bottom. The face reinforcement in clay, to limit the risk of face extrusion, was carried out by fiber glass bolts.

The presence of groundwater required the design and drilling of preliminary horizontal sealing injections, around the excavation outline.

The presence of sensitive and very sensitive neighbors imposed an excavation method inspired by ADECO-RS.

The project is part of a highly constrained urban site that forced to take into account hard obligations to the site operations and to the logistics too.

For phasing reasons, the access to the tunnel was built through a 26 m deep armored shaft, to fill after tunnel excavation, allowing station excavation.

Ganntas tunnel and Ramdane tunnel of the new El Affroun - Khemis Miliana railway line (Algiers - Oran line) - Algeria

Head of the Tunnels Department (MOE) of the El Affroun - Khemis line (55 km).

Validation of the technical design, of the building procedures and of the methods statements. Management, organization of works supervision teams. Monitoring work on site and expertise on critical points. Monitoring and updating Planning and work schedule. Management of the design variants and audit of the additional prices of the Ganntas and Ramdane Tunnels. (2014-2015).

Ganntas : this is a twin-tubes tunnel, each 7.4 km long, to be excavated using the traditional method, in a massif having its overburden up to 500m. Excavation area 39 m2. Mixed-face: fractured marl in vault, very swelling clay in the invert. Contractor is the Chinese company CCECC.

The face reinforcement of the clay layer, to limit the face extrusion, was carried out by fibers glass bolts.

The excavation was carried out working on 4 sides at the same time.

Ramdane : this is a 2.8 km single-tube tunnel, to be excavated using the traditional method. The transversal section of the tunnel has R = 5.45 and area = 75 m2 , the max overburden is 250 m. The excavation of the tunnel was in slightly fractured marls with significant water inflows (5-10 l/s).

The excavation proceeded, working on both sides at the same time, with NATM method by the Turkish company OZGUN.

Relizane - Tiaret - Tissemsilt railways tunnels and civil works in Algeria

Head of the Tunnels and Civil Works Department (MOE) of the new Relizane-Tiaret-Tissemsilt railway line (185 km) in partnership with "TPF".

In charge of the coordination and work supervision on site through a local team. Validation of the technical design and of the building procedures. Site monitoring and geotechnical campaign management. (2012-2013)

This project includes the construction of 4 tunnels (RT 3010 RT 3030 RT 3040 RT 3050) having length respectively 1.102 m, 799 m, 540 m, 800 m. The four tunnels excavated with NATM method, with Hydraulic Hammer in consolidated marl, sandstone and sand. Excavation section: 115 m2. Contractors JV: FCC + ETRHB (Contract 900 M €).

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Tunnels of the Chengdu-Chongqing HS railway line - Lot n° 2 - China

Project Director and Head of Tunnel Works Direction (MOE) for Lot n.2 of the new HS Chengdu - Chongching railway line (112 km). Supervision activity in partnership with "Sichuan Tieke supervision construction Co. Ltd".

Responsible for the organization, coordination and supervision of works. Responsible for contract management, budget and in charge of official communications. Validation of work procedures and methods statements. Site monitoring and expertise on critical points, particularly geotechnics. HSE and Quality coordination. (2011)


The line is 60% made up of long and medium-high railway bridges. 12 Tunnels excavated with NATM method, using explosives (“smooth blasting method”) in marl and fractured rocks. The site was in agricultural and isolated areas afficted by reduced communications.


Quitaracsa hydraulic tunnel (Peru)

Underground Works Manager (Moe), in charge of supervision and technical monitoring of the underground works of the Quitaracsa hydroelectric project (2011 - 2015).


13 km of tunnels, including 5 km of high water hydraulic pressure tunnel (80 Bar) and 3 operational caves (cost of works M € 250).

The underground works of the Quitaracsa power station are carried out in the granodioritic batholith of the "Cordillera Blanca" in the Ancash region, subjected to high tension stresses due to the large lithostatic cover (more than 1000 meters) and to the transverse tensions caused by the many tectonic faults present.
From the beginning, advancement was difficult due to the occurrence of strong mountain blows (more than 40 events), which forced the installation of a protective mesh on the roof of the tunnel (or the use of shotcrete ).
The presence of strong water flows in not unexpected areas, for the crossing of regional faults, with pressures higher than 40 atmospheres and flows around 70 liters / second, forced several times the stop of the excavation works to carry out pre-injection campaigns on the working face using cement grout, to seal the front and allow the advancement to progress.

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2nd tube of the Croix Rousse Tunnel in Lyon (France)

Underground Works Manager of the Construction Management Office (Moe), in charge of control and site supervision of the second tube of the Croix Rousse tunnel project (2012 - 2014).

Excavation by traditional methods (with explosives) of a new tube of about 1,760 m called "North Tube" whose primary function is to serve as a safety and rescue gallery of the road tube to which it is connected by 11 by-passes.

This tube, with its width of 10 m, is designed to allow the passage of "soft modes" (pedestrians, cycles and small buses, with the possibility of a two-way tramway instead of buses).

The entrance of the tunnel on the Rhône side, located on a steep slope and in an urban environment, was carried out by means of a nailed wall 30 m high, on an area of approximately 550 m2. The wall is anchored to the soil by nails with a cumulative length of more than 3 km and by two top beams.

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Connection tunnel to Bologna HS railway station. Lot 8a of the new Bologna-Milan HS line (IT)

Responsible for the validation of the variant design plans, the monitoring of the works, process for the acceptance of the building materials.

Responsible for the acceptance trials, quality assurance, planning, works journal, accounting and validation of monthly progress (2003-2005).

It is a 1.2 km long tunnel, to be excavated following the traditional method, with the alternative use of a ripper and hammer, with a section of 105 m2. Mixed front face with prevalent granular soil including frequent clays layers.

The excavation followed the Italian method (ADECO_RS): the first stretch thanks to the soil improvement by vertical, massive jet grouting and then by means of vault umbrella of injected micro poles together with horizontal fiber glass bolts to assure the face stability.

Vertical jet grouting field have been necessary also to underpass a railway line.

It includes the construction of an access shaft before the starting of the tunnel excavation, appropriated to become permanent with the function of emergency and rescue shaft. The work has included also the support of a building by compensation grouting.

Value of the works: 80 million Euro. “Condotte” contractor company.

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