TABELLOUT - razel-bec.com

Destination... TABELLOUT

magazine

SPECIAL EDITION

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Editorial Staff: Isabelle Sacquet and all named persons

Photo credits: Thomas Léaud, Image & Process, RAZEL-BEC/DR

Design and printing: Hawaii CommunicationTel. +33 (0)130 053 151

Circulation: 2,000 copies Printed on paper sourced from

sustainable forests. BVQI No. PEFC/10-31-1086

RAZEL-BEC magazine N° 05 / April 2015Published by RAZEL-BEC

3, rue René Razel – Christ-de-Saclay91892 Orsay Cedex, France

Tel. +33 (0)169 856 985razel-bec.com

Publication Director: Jérôme PerrinEditor-in-Chief: Isabelle Sacquet 03

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// Éditorial

// autonomy & cutting-edge equipment

// tunnel

// razel in algeria

// people and occupations

// major projects & export

// interview

// dam

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60 years of shared historyRazel and Algeria have been walking hand-in-hand since 1954, the year in which the company started work on a great many projects on the southern bank of the Mediterranean. Earthworks, civil engineering, industrial and railway developments, airports, highways and linear infrastructures, the growth in the company’s all-round expertise has mirrored the projects of our Algerian partner.

To firm up its intention to establish a sustainable presence in Algeria, Razel created a subsidiary, Razel Algérie, in 1999.

Razel has therefore naturally been in the frame for the country’s major projects, particularly in the area of water and infrastructures.

In August 2002, the company won the international tender for Koudiat Acerdoune Dam. This involved constructing a straight gravity dam using the roller-compacted concrete (RCC) technique. Standing 121 metres tall, the dam is 134 metres thick at the base, 8 metres thick at the crest and covers a length of 490 metres. A total of 1,850,000 m³ of concrete were used, including 1,525,000 m³ of RCC. It is one of the tallest dams ever built using the demanding RCC technique.

Our successful efforts on this project have been rewarded, as one year on from completion of the work on Koudiat Acerdoune Dam, our client, the Algerian National Agency for Dams and Water Transfers (ANBT), showed its trust in Razel by awarding us the Tabellout Dam contract in March 2010.

Tabellout Dam will have the particular feature of being one of the few RCC dams with an arched profile to withstand seismic stress. A complex, yet innovative piece of engineering, this new structure confirms the extent to which Razel’s teams master specific know-how on major projects.

I trust that you will enjoy reading this special edition devoted to the construction of a new monument to which the teams in the field are showing total dedication. The company and every single employee can take a great deal of pride in this accomplishment.

éditorialLaurent Fayat CEO

// people and occupations

04 RAZEL-BEC / magazine No. 05 / April 2015Special Edition Destination Tabellout

Alongside its involvement in the country’s major hydraulic projects, Razel Algérie is also in the frame for numerous other public and private-sector pro-jects. Discover this subsidiary with Walid Baghriche, Director of Razel Algérie.

Having studied in both Algeria and France, where he obtained a Post-Graduate Diploma in International Business, Walid Baghriche joined Razel-Bec and its subsidiary Razel Algérie after 13 years with Thalès. He has been in charge of the agency since 2010. “Razel is highly respected in Algeria where it has been part of the local landscape since 1954. I am proud to represent this French group in my country of birth and to manage the type of far-reaching projects on which the company’s international reputation is built,” he confided.The subsidiary has continued to grow throughout its 60 years in Algeria. Originally operating as a “support base” for the major projects conducted in the country, it has, with head office backing, become an auto-nomous entity with a strategy of esta-blishing a lasting presence combined with in-depth local knowledge of the projects and the people behind them.

Local identity“Our aim was to integrate Razel Algérie into the local fabric,” Bagriche explained. “We have managed to achieve this and this is what makes us unique. We have obtai-ned the certifications required to respond to national invitations to tender and this opens doors to projects that only local companies can bid for.”

In addition to the major RCC projects such as Koudiat Acerdoune (see page 7) and Tabellout, Razel Algérie is also moving into other fields. The Subsidiary Director analysed the situation: “Our multi-skilled expertise and our references put us in a strong position as civil engineers to be involved in large-scale energy projects in Algeria, where internationally-recognised technical know-how and proven ability to work locally are crucial.”

RaZeL in aLGeRia

FULLY INTEGRATEDAND HERE TO STAY

Walid Baghriche

Back, left to right: Aissa Keddache, Omar Sebhi, Ismaïl Ramdani,

Yazid Bettahar, Aziz Belarbi, Mahfoud Hasnaoui, Walid Baghriche,

Roger Dunand-Chatellet.Front, left to right:

Souhila Si Larbi, Abdelhalim Mansour, Amel Chennafi, Mahmoud Hebache, Hassina Maala.

“Razel is highly respected in Algeria

where it has been part of the local landscape

since 1954.”

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Razel Algérie’s Administrative and Financial Director, Ismaïl Ramdani joined the company in 2001. He is part of the team that created Razel-Bec’s Algerian subsidiary.

“Razel has forged its reputation as a solid company that has built itself up and developed within the Algerian legal framework. Our greatest asset lies in the fact that we have trai-ned and placed our trust in local managers to create an autonomous, operational team in spite of active competition and a difficult economic context.”

Ismaïl Ramdani

Private-sector projectsBoosted by its local identity, Razel Algérie has also turned towards private-sector markets in developing its commercial acti-vity. Médéa quarry, located 120 km west of Algiers, started operation in April 2014 after a six-month facility setup period. The limestone deposit amounts to three million cubic metres. Annual production targets are set at 500,000 tonnes.

For Walid Baghriche, local identity and an entrepreneurial mindset are not the only factors that characterise Razel Algérie. “The human dimension lies at the heart of the company’s values. We are committed to encouraging our expat and local employees to move forward together on a common project. Training facilities have been set up and resources allocated for this purpose, to bring a human element to the company’s global business plan.”

RAZEL IN ALGERIA: a LonG HistoRY

1954Razel set up business in Algeria to build the Still-Touggourt-Hassi-Messaoud road (370 km) and, over the following ten years, progressed from project to project:• 1,500 km of oil roads, Algiers and

Constantine aerodromes• Tifoune pipeline (212 km)• El Akoun steelworks• Algiers Olympic Stadium.

1966The company played an active role in the construction of the El Hadjar steelworks near Annaba. The Contracting Authority was SNS (Société Nationale de Sidérurgie).

1974Establishment of a public-private partner-ship, Genisider, that developed significant-ly with widespread diversification over a 15-year period. Its major projects: • El Hadjar steelworks• civil engineering of the Ghardaïa, El

Eulma, Réghaïa, Tiaret and Biskra works• Ras Djinet and Jijel power stations• Annaba and Tiaret international airports• Annaba-Berrahal motorway• Ouled Mélouk Dam near Chlef…

1988Cooperation continued in the form of a technical assistance agreement for the construction of the first line of the Algiers metro system.

1992Razel signed a technical assistance agree-ment for repair work on the Baaziz railway tunnel in Médéa on the Blida-Djelfa line.

1999Razel set up Razel Algérie, incorporated under Algerian law and based in Algiers.

Medea quarry


France adopted first Roller Compacted Concrete (RCC) technology. Razel-Bec has acquired unparalleled expertise which has opened up the market for large RCC dams all over the world.

Built by the Major Projects & Exports Division of Razel-Bec, Tabellout Dam is a 121-metre-tall, arc-shaped structure com-prising a 13.5 km transfer tunnel excavated by a tunnel boring machine. This com-plex, yet innovative work illustrates Razel-Bec’s widely acknowledged know-how and expertise. The earlier Koudiat Acerdoune Dam experience (see opposite) enabled the company to gain proficiency in RCC, an increasingly sophisticated material that calls on the development of quite specific production methods and demands that stringent implementation constraints be observed.

Autonomy and materials proficiency

Over a million cubic metres of RCC are required to build Tabellout Dam. A com-plete industrial process was therefore set up on site, upstream of the dam, to produce and transport the RCC. The aggregate used in the RCC was also produced here.As Jean Guillaume, the Deputy Managing Director responsible for Major Projects and Exports, pointed out: “This dam highlights the company’s ability to manage projects that bring together up to 1500 people of various nationalities. The management teams in the field are used to coordinating local, international and expat staff and tackling technological challenges collec-tively. I might add that the support teams at head office offer first-rate administra-tive backing and advice to deal with legal, contractual and accounts issues.”

“With the two Algerian dam projects – Koudiat Acerdoune and Tabellout – and the one at Rizzanèse in France, we have built up a solid track record in terms of RCC technology. Thanks to this expertise, Razel-Bec has embarked on a strategy of partnerships with several foreign companies with a view to bid-ding for the large-scale international dam projects, and RCC dams in particular, that are currently emer-ging in South-East Asia and in the Near and Middle East.”

Jean-Philippe Cattin, International Projects Director

MaJoR PRoJeCts & eXPoRts

tHe eXPeRts IN RCC DAMS

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KOUDIAT ACERDOUNE DAM

“ Two major activities – Dams and Tunnels – are represented in this project. The experience acquired through the combination of the two is valued within the Company. Young engineers can benefit from it by being offered training opportunities and the possibi-lity of acquiring new experience on high-pro-file projects.”

Jean Guillaume, Executive Vice-President

This structure, located in the Isser river valley in the region of Lakhdaria, this structure started to operate in October 2008. It is an RCC gravity dam supported by a rock foundation consisting of marly shales. The 121-metre-tall dam supplies drinking water to 800,000 people (101 million cubic metres per year) and irri-gates farmland in the East Mitidja and Lower Isser regions (69 million cubic metres per year). With a 134-metre-thick base, the dam is 490 metres long and 8 metres thick at the crest. As 1,850,000 m3 of concrete (including 1,525,000 m³ of RCC) were required to construct the dam, numerous facilities had to be set up: pumping stations and water and alluvial treatment plants, filler production plant (40 t/h), RCC production station (100 t/h) and an electricity generating unit (11,000 kVA) to power the site.

Left to right: Cédric Tinel, Zahia Benséghir, Hicham Allouche, Jean-Philippe Cattin, Sophie Renard, Arnaud Watel, Marlène Gorlier, Sébastien Poli, Marie Auriol, Sophie Flachez, Catherine Martinez, Samantha Fabre, Stéphane Le Gall and, in the centre, Jean Guillaume.


Tabellout Dam and its 13.5 km transfer tunnel, part of the Government’s water management programme, will be the fifth structure of this type in the country. The National Agency for Dams and Water Transfers (ANBT) sought advice from the consulting engineering firm Coyne et Bellier for the dam and Safège for the tunnel. Razel’s experience on the Koudiat Acerdoune dam project is a major asset for this demanding job where tight, smooth-running organisation and operation are crucial.We met Mustapha Rabei, ANBT Director of Developments - Centre (DRC).

Sétif Province. The aim of this system is to supply 42.5 hm3 of drinking water per year to 16 towns in the eastern part of Sétif Province and 151 hm3 per year to irrigate the El Eulma Plain.

What is the other development?

M. R. - The West system is based on the transfer of water from the existing Ighil-Emda Dam (Béjaïa Province) to the Mahouane reservoir (Sétif Province). It is intended to supply 56 hm3 of drinking water per year to 12 towns in the western part of Sétif Province and 66 hm3 per year to irri-gate the Sétif Plain.

What does Tabellout Dam repre-sent?

M. R. - With a storage capacity of 294 mil-lion cubic metres, Tabellout Dam, which is currently under construction, will rank among Algeria’s largest dams. This struc-ture, located in the Djendjen river valley in the municipality of Djmila (Jijel Province), is the starting point of the East system of the HPS development. Its Roller-Compacted

What is the overarching challenge facing this development?

Mustapha Rabei. - The Sétif High Plains (HPS) development programme is particularly important given the dimension of the plan-ned structures, both in terms of their technical and economic parameters, and the social objectives that will be assigned to them.When completed, this development will be used to transfer a volume of 313 million cubic metres of water for the purposes of supplying drinking water to a population of around two million in 28 towns in Sétif Province by 2040, and irrigating around 36,000 hectares of farmland on the plains of El Eulma and Sétif.

How is the Sétif-Hodna project structured?

M. R. - The Sétif-Hodna transfer project comprises two distinct developments.The East system consists in transferring water from Tabellout Dam, located in Jijel Province, to the Draâ-Diss reservoir in

Mustapha Rabei,ANBT Director

of Developments – Centre

inteRVieW

RaZeL AT THE HEART OF A MAJOR WATER TRANSFER SYSTEM

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For over twenty years, Algeria’s limited, vulnerable and unequally distributed water resources have been suffering

from the combined harmful effects of drought and pollution while, at the same time, the country’s needs have continued to increase under the joint effects of eco-

nomic and demographic growth. To tackle the issues posed by chronic water shor-

tage, the Algerian Government has imple-mented an ambitious water management

and resource optimisation programme, integrating all existing solutions: well

drilling and aquifer pumping, seawater desalination, and dams with water trans-

fer. The Tabellout project, which falls into the latter category, will bring the number

of dams in activity to 58, twelve short of the target of 70 dams with a total capacity

of eight billion cubic metres.

• strengthening the right bank to preserve stability in the structure’s final configura-tion (this was done as a result of instabi-lity being recorded during construction);

• eliminating the grouting platform at the foot of the slope, replacing it with grou-ting from the gallery.

Concrete (RCC) design makes it the fifth dam of this type in Algeria.

Is Tabellout Dam similar to Koudiat Acerdoune Dam, built by Razel for the ANBT in 2009?M. R. - Tabellout Dam is similar to Koudiat Acerdoune in that they are both made from Roller-Compacted Concrete (RCC). However, its storage capacity is different.

Have the construction constraints changed since the start of the project?

M. R. - During construction work on Tabellout Dam, the presence of a poten-tially active fault was localised 200 metres upstream of the dam axis, which led to some major changes and adaptations to the design of the structure. These included: • an arch shape to concentrate the stress in

the banks in the event of an earthquake;• consolidating the base to improve its geo-

technical and geomechanical properties and avoid differential settlement;

SETIF

Erraguen

TABELLOUT

Wilayade Sétif

Wilayade Jijel

Draâ Diss

EAST SYSTEM: setif-HoDna


In 2010, the ANBT awarded the Tabellout dam and tunnel contract to Razel. One year later, new seismic legislation forced changes to the initial dam pro-ject with the ANBT increasing the thickness of the tunnel segments. This had a profound impact on the management of the construction project, the orga-nisation of which was already complex due to the distance between the dam and tunnel sites. However the teams headed by Hervé Guerpillon, Manager of the Tabellout dam and Aïn Sebt tunnel project, have managed to adapt.

tWo PRoJeCts in one

RaZeL ADAPTS AND RISES TO THE CHALLENGE

Due to new seismic legislation, the pro-posed geometry of Tabellout Dam chan-ged from a straight to an arched profile – quite rare on this type of structure. Hervé Guerpillon, Project Manager, explains the reasons behind this decision: “To inte-grate the new design calculation values, we would have had to design a more mas-sive structure and increase the volume of roller-compacted concrete by 70%. Faced with this solution, which would have pushed up the price tag to a level that the cus-tomer would have had trouble accepting, the Engineering Consultants suggested reviewing the shape of the dam. With the new arched geometry, the increase in the volume of RCC was kept to a minimum – it now totals 1,000,000 m3”.

Hervé Guerpillon, Project Manager

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Changes compared with the detailed design

The main changes made to the design were:• transfer of the bottom outlet to the centre

of the dam• inclusion of an antiseismic beam in the

top part of the dam• elimination of the intermediate berms

making construction site access more difficult for heavy plant

• creation of shear keys (see page 14 for explanations) with associated grouted joints, thereby increasing the total num-ber of joints and, therefore, the number of blocks

• creation of inclined galleries linking the drainage galleries (perimeter galleries)

• consolidation grouting.

tWo PRoJeCts in one

RaZeL ADAPTS AND RISES TO THE CHALLENGE

Effects on site organisation

The impact of these changes was further amplified by a landslide in June 2012, at the exact location of the bottom outlet.“In spite of these major changes, it was decided together with the customer not to stop construction. The impacts meant that we had to reorganise and refocus on the bottom outlet,” Hervé Guerpillon pointed out, before detailing the consequences: “sequencing and progress were revised and the schedule extended.”The construction site, designed to lay 65,000 m³ of RCC per month, finally achie-ved just 30,000 m³ per month during the so-called “downgraded” phase of reorga-nisation. The restrictions relating to this downgraded mode having recently been lifted, the RCC can now be laid at the plan-ned rate.Scheduled RCC laying time has consequently been adjusted from 15 to 23.5 months.

“The ‘contract management’ aspect is important on all projects. On the Tabellout dam and tunnel project, its importance was taken to quite another level. Contract management means defending the company’s interests by ensuring in particular that the terms of the contract are properly applied. This is of course done with the support and legal insight of the Algiers office and our headquarters in Saclay.”

Jean-Philippe Maillard, Contract Manager

One of the specific features of the project lies in the fact that it is split into two dis-tinct sites located around 15 kilometres apart as the crow flies. This meant setting up two independent Works Management teams, although headed by the same Project Management team.From their main base at the Tabellout Dam site, Project Management provides contractual and logistic assistance to the Aïn Sebt Tunnel “South Head” teams led by Sylvain Mandégout.

aïn sebt TUNNEL


“Twenty staff work at the laboratory testing all the materials used on the construction site. We must be extremely vigilant with regard to the constituents of concrete, and especially RCC, which are produced at the site by the Materials Unit, the cleanliness of which in particular is regularly monitored.The laboratory is also in charge of establishing formulas for concrete and for RCC, as well as inspection (specimen sampling and crushing, and compaction testing for example). We also install auscultation devices within hydromecha-nical facilities…”

Giuseppe Abbagnato, Senior Laboratory Technician

“Versatility and anticipation are the key words that define the 18-strong Topographic & Quantity Surveying team working on the dam and tunnel, in constant liaison with the work crews and customer representatives. We col-late a host of information that will enable the dam to be built. Other important aspects of the mission include quantity tracking, issuing daily statements of work completed, preparing and presenting progress reports, participating in the preparation of negotiation documents, as well as managing the numerous construction drawings up to the ‘as-constructed’ files.”

Alexandre Espéret, Engineer, Quantity surveyor

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“When it comes to safety, quality and the environment, the demands are no different to any other of the company’s projects. Around 20 ‘red vests’, split between three shifts, watch over staff safety on the dam 24 hours a day.

Omar Bouacha, Head of HSE

“The various unforeseen events encountered and the company’s adaptability to the new constraints have made this a particularly outs-tanding and dynamic project! The chance to contribute to such a project does not come along very often.”

Dominique Certo, Head of Methods, Engineering & Planning for the dam

“Subcontracted work primarily includes boring and grouting (Sefi Intrafor, Fayat Group), HEM work (Calzoni Hydro and its local partner Alieco), electrical work (Calzoni Hydro and its local partner PM2I), auscultation (Telemac), and the metal bridge over the spillway. The scheduling of subcontracted activities and their integration into the master schedule are accompanied by day-to-day monitoring of the subcontractors through every stage: factory manufacturing (in Italy and Algeria), logistics, transportation or site assembly, not forgetting the design work specific to the hydromecha-nical and electrical activities, for which the Consortium and its subcontractors are responsible, through to approval by the ANBT and its engineering consultants.”

Roberto Rossetti, Head of Subcontracting for the dam


AN RCC ARCH DAM

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16 RAZEL-BEC / magazine No. 05 / April 2015Special Edition Destination Tabellout Dam

This 121-metre-tall dam, with an associated 13.5-km-long TBM-excavated water transfer tunnel, has the unusual feature of being one of the few dams of this type designed with an arched profile. To construct the dam, almost one million cubic metres of roller-com-pacted concrete (RCC) are required. We were accompanied on our visit by Rachid Amari, the Dam Construction Manager.

AN innoVatiVe YET DEMANDING STRUCTURE

In Algeria, a little over 350 km to the east of Algiers in Jijel Province, the Tabellout Dam construction site is running at full capacity. The site is isolated with difficult access, and very steep slopes. Thirteen kilometres away, as the crow flies, at the Aïn Sebt site, tunnel excavation work is underway. A hard-rock tunnel boring machine is driving towards the dam. The distance between the two sites is 30 kilo-metres by the most direct road. Owing to these various constraints, Razel has natu-rally organised itself by splitting into two fully autonomous, in situ operations for the dam and for the water transfer tunnel.

Complex construction

The structure is built from 14 blocks sepa-rated by six grouted “keyed” joints and seven simple (ungrouted) joints. These joints are designed to guide concrete contraction and are protected upstream by waterstops preventing the passage of water between the blocks. Keyed joints, 50 metres apart, are intended to be grouted to offset the contraction effect and encourage arch action. They consist of two to three compartments equipped with grouting and auscultation devices and shear keys in the shape of a quadrangular prism to transmit shear from one block to the contiguous block. This complicates the construction of the actual dam considerably. When com-pleted, it will take the form of an arched structure with a developed length of 392 metres and a thickness of 8 metres at the crest, a base length of 100 metres and a height of 121 metres,” explained Rachid Amari, the Dam Works Manager.

Rachid Amari, Dam Works Manager

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It comprises a stepped central spillway, a perimeter gallery and a low- or mid-level discharge gallery.The construction of an antiseismic belt between the abutments, in the top part of the structure, at the spillway sill, consisting of a concrete beam reinfor-ced with 64 HA-40 mm diameter bars is designed to strengthen the dam and limit the “piano effect” in the event of an earthquake.

During the preliminary phase of the project:• two temporary bypass tunnels measuring

380 and 431 metres long respectively,

Project Data•

Contracting Authority: ANBT (National Agency for Dams and Water Transfers)• Dam and Tunnel Designer: EDF CIH• Consultant Engineers to Contracting Authority: Coyne & Bellier/Safège• Contractors: RAZEL/CMCRA/Tabellout Consortium• Funding: Algerian Government• Scheduled completion date: late 2015

with a 6-metre “horseshoe” cross-sec-tion, were excavated by blasting in order to divert the river from its bed during the work phase. These two tunnels will be sealed once construction is complete;

• two temporary embankment-type coffer-dams were built, one upstream and one downstream, to protect the construction zone while the dam is being erected.

The purpose of the project is to transfer water from this very wet part of Algeria where annual precipitation can reach 1.50 metres (twice the French average) to the Sétif region, some 80 km away.


Since March 2014, the production and laying of RCC at Tabellout Dam have really taken off, passing symbolic milestones on the way. At 500,000 m³, half the total volume of RCC required had been output by mid-June and, on 4 August, the dam reached its mid-height point 60 metres above the foundation, at elevation 271, corresponding to 60% of the total volume of RCC.

On Monday 16 June 2014, the symbolic barrier of 500,000 m³ of RCC laid was broken: “To achieve this, we exceeded an average daily rate of 3,000 m³ over the six working days to clock up 18,332 m³ in a record week, and 70,961 m³ during the month of June”, Hervé Guerpillon announced.

“The arrival of summer with its high temperatures and the necessary alterations to work schedules during the month of Ramadan – which meant that RCC was laid only at night – have prevented us from beating this record, but we should manage it in September.”

a sWift PaCe FOR THE WORKFORCE

“From March to August 2014, the dam height consistently rose 1.20 metres - a lift of four 30 cm layers - per week, which meant that we reached elevation 271 early August. This elevation corresponds to half the final height of the dam, which will comprise 100 such lifts, midway between the trench bottom at elevation 211 and the final elevation 332.Each lift is itself made up of a variable number of blocks depending on its placement in relation to the height of the dam – four at the base, seven at the top – of variable volume (around 2,500 m3 per block in the current phase). At present, each block is laid in around ten hours on average.”

Hervé Guerpillon, Project Manager

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To manage the Tabellout project, Razel calls on a number of experts, and notably Brian Forbes, the international dam specialist. He is pictured here with Jean-Philippe Cattin, Giuseppe Abbagnato, Ouchene Hamza, Jean-Claude Mogno and Rachid Amari.

Douadi Boultif, Senior General Foreman–Earthwork and RCC, flanked by

Jean-Claude Mogno and Rachid Amari. He is the principal architect

of RCC laying for the dam.

Below: Angelo Trevisan, Senior Site Foreman, with Rachid Bettahar to his right and Abdesllam Atamna to his left.


A demanding form of concrete

“The first constraint is the fact that a layer must be placed on top of a layer which has still not set (after just a few hours), which implies flawless continuity and consistency in the placement,” Rachid Amari explained. A number of redundant items of equipment must therefore be kept available and any unexpected events must be met with an immediate response.Another constraint, which only applies however in the summer months, is the fact that RCC must be laid on the dam at a tem-perature not exceeding 25°C to limit fissu-ring. This implies cooling the concrete.

The development of RCC can be explained in particular by two main advantages: its adaptation to geology is less demanding than for conventional concrete structures, and the possibility of incorporating intake and discharge works into the dam body, unlike rockfill dams. A further advantage lies in the use of aggregate produced on site. The difference with conventio-nal concrete lies in its consistency which enables it to support compaction by a heavy vibrating roller – in this respect, the material must offer intrinsic qualities and specific properties on laying (strength, den-sity, impermeability, durability, workability and segregation) to guarantee the absence of weak zones in the structure, particularly with regard to water tightness.

Roller-compacted concrete is a relatively recent technology as the first RCC dams were built in 1980. Since that time, more than 250 have been construc-ted throughout the world. This process obviously has its advantages, but also some serious constraints.

RCC: A CoMPLeX PRoCess

“Generally, when we have to cool conventional concrete, we use cold water or even crushed ice. In the case of RCC, as the quantity of water added per cubic metre is very low (less than 100 litres), we must cool not only the water but also the coarser aggregate. For this purpose, we circulate cold air through the high-volume storage silos to lower the temperature to around 12–14°C. The cold air is pro-duced by a machine that operates in a similar way to an air conditioning system but with a 750 kW power rating. Considerable construction work is also necessary to stockpile sufficient materials for chilling to ensure at least 15 hours’ supply of cold aggregate.”

Rachid Amari, Dam Works Manager

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Quantities• Volume of RCC: 1,000,000 m3

• Volume of CVC: 80,000 m3 divided

between the dam (40,000 m3),

reinforcement (20,000 m3), and

site installations (20,000 m3)


At the construction site, they are known as the “noble parts”. Deep down in the concrete bowels of the dam, these highly complex civil works will never be seen. And yet this is precisely where the dam’s engineering comes to the fore and where it is auscultated!

at tHe HeaRt OF THE DAM

“The HEM – Hydro-Mechanical – systems comprise sheet metal and mechanical equipment designed

for the management of the water retained by the dam. In the case of Tabellout Dam, this involves primarily

the pipework and the valves of the low-level and mid-level discharge systems; the water intake and pumping works are not included within the scope

of the contract awarded to Razel.”

Jean-Claude Mogno, Works Engineer

For installation and maintenance opera-tions, the two chambers are equipped with an overhead travelling crane as some of the valve components can weigh as much as 20 tonnes. The valves are operated by hydraulic cylinders.

UPstReaM VaLVe CHaMbeR A room located within the dam, housing the valves used for partial discharge (mid-level) or total discharge (low-level) via a metal pipe with a diameter of 3.60 metres, embedded in the RCC. The upstream chamber comprises a bulkhead gate-type valve and two fixed-wheel gate-type valves. The mid-level bulkhead gate will be instal-led halfway up the dam. These four gate valves operate vertically. The bulkhead gates enable maintenance to be performed on the fixed-wheel gates.

DoWnstReaM VaLVe CHaMbeRRoom outside the dam, located on the downstream left bank, housing the radial gate that releases and regulates the discharge rate. This gate has a cylindrical segment shape and moves in a semi-circular motion. In this downstream ser-vice building, the radial gate leads to the discharge deflector.

For traditional farming activities, such as crop cultivation, market gardening and livestock rearing, the HEM installations are designed to maintain a permanent flow of compensation water in the riverbed downstream of the dam.

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Galleries

A network of internal galleries is built into the dam for monitoring purposes (dam verticality, movements and other ausculta-tion parameters) and for operations during or post-construction (grouting, drainage, etc.).These galleries positioned in the upstream part of the dam are particularly used to drain off any water infiltrating through the upstream face, the left and right abutments and the dam base. This drain network is produced by boring following dam construction and sealing of the joints by grouting.

Low-level and mid-level drainage pipes.

Upstream valve chamber.Access gallery to the upstream valve chamber.


This drainage water is discharged by gravi-ty through the following network of internal galleries at three levels (low, mid and high).

• Galleries in the right and left abutments: these six (3x2) underground galleries are approximately 60 metres long, have a 3-metre “horseshoe” cross-section and follow the arched shape of the dam. They are excavated using traditional techniques and the roof is lined with non-reinforced concrete.

• Dam internal galleries: these three galleries are constructed by shuttering on laying the RCC, and with prefabri-cated cover slabs. As requested by the Customer, the surface of the vertical walls of these galleries is left “as laid” to enable the evolution in the RCC to be monitored. These dam internal gal-leries are combined with declines for level-to-level access via stairways and ramps, the gradient of which is as high as 45°.

• Drainage galleries: these six (3x2) galle-ries discharge drainage water by gravity at the left and right banks downstream of the dam, in addition to providing ventilation. Bearing on the bank slopes, these reinfor-ced concrete galleries are placed before the RCC. To date, just one access to these galleries is planned (downstream of the lower left bank gallery). This road access will be shared with the upstream valve chamber gallery.

• Access gallery to the upstream valve chamber: this is the gallery made in the body of the dam on the left-bank side. This 4.50 x 4.50-metre gallery provides access to the upstream service building, com-monly called the upstream valve chamber.

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Dam originally planned: straight profile

Visit

Antiseismic beam

Network of internal galleries

Rotec route

Dam under construction: arched profile


27

AUTONOMY & CUTTING-EDGE EQUIPMENT

28 RAZEL-BEC / magazine No. 05 / April 2015Special Edition Destination Tabellout Equipment

The Equipment Resources teams provide the logistic support and autonomy that the concurrent dam and tunnel construction sites need. The Equipment Resources Manager, Jacky Legras, reviews the issues tackled by an impressive setup.

assessMent, PeRfoRManCe, aUtonoMY, antiCiPation

PLant ISSUES

The first issue is to assess exactly what equipment is needed and to avoid com-mitting an error in plant specification. If it turns out be the wrong choice once construction is under way, particularly relating to production plant, this will have a negative impact especially on the schedule.

1. assessMent

Jacky Legras, Plant Manager

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Another issue given the distance and the difficulties involved in transport and impor-ting equipment into Algeria is to ensure that we have the resources on site for total command over all the equipment in place and that they fully master absolutely all the technologies used so that we can be fully autonomous. In the event of a breakdown on the RCC plant, for example (whether it be mechanical, electrical, electronic or computer-related), it would be inconcei-vable to bring in a specialist from abroad who would, at best, take a few days to get here.

The second issue is to achieve maximum performance very quickly. The running-in period must be as short as possible. We rely on very heavy industrial facilities (a material production unit with an output of 650 tonnes/hour, a 1,000 tonne/hour continuous concrete mixing plant and a 1,000 tonne/hour Rotec conveyor) that in the aggregate or concrete industry would be installed for 30 years, whereas we install them for 24 months. So nothing must be left to chance, either in the specification, rigour and quality of the plant, or in the support resources required to ensure optimum ope-ration which will in turn guarantee optimum performance.

2. PeRfoRManCe

3. aUtonoMY

The final issue is the need to have a great sense of anticipation. In Algeria probably more than anywhere due to the distance involved and the difficulty in reaching the site, the option of importing parts at very short notice would appear to be impos-sible. Even if, by definition, a breakdown is unpredictable, efforts must be made to anticipate it to avoid being caught short when it does occur. We have to pinpoint the fine dividing line between stocking too many spare parts and supplies, with the inherent costs that this generates, and not stocking enough which may impinge on efficiency, and which would also represent a cost.

4. antiCiPation

“As on the Koudiat Acerdoune Dam project, we have put the necessary structures in place to guarantee complete autonomy.”

Jacky Legras, Equipment Resources Manager


THE PRoDUCtion CIRCUIT

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2

8

10

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1- Alluvia mining areas (downstream borrow material)

2- Material processing unit3- Filler manufacturing plant4/5- Filler and cement storage

silos6- RCC plant

7- CVC plant8- Rotec conveyor9- Dam10- Service base11- Catering/Ancillary operations12- Base camp13- Workshops and stores

3

4

5

6

7

9

11

12

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It’s not the end of the world... but almost! Considering the remoteness of the site, the Equipment Resources department is structured into four divisions that must all be able to work cross-functionally, but also in complete autonomy. Let’s have a closer look at the people who are constantly on the look-out to counter the slightest difficulty and ensure uninterrupted RCC production and, consequently, uninterrupted dam construction.

PRoDUCtion, MeCHaniCaL enGineeRinG, eLeCtRiCitY, LoGistiCs

A sMootH, aUtonoMoUs ORGANISATION

The production facilities employ 160 people. They include the materials unit which pro-duces the aggregate, the filler manufac-turing plant, the CVC and RCC plants and the Rotec conveyor (see article on pages 36 and 37). These facilities are capable of instantly outputting 650 tonnes/hour of crushed aggregate and 1,000 tonnes/hour of concrete for roller compacting.

“Participating in the building of a dam is the ultimate experience in the construc-tion world. After Koudiat Acerdoune, working on Tabellout Dam seemed to me to be an obvious step and yet having responsibility for the production facilities is a real challenge. We are responsible for the entire RCC produc-tion line, from processing the aggregate taken from the river valley to conveying the RCC to the dam. The expats in our team are all working on their second dam for Razel! When it comes to meeting increasingly tough budgetary, environmen-tal and safety targets, such experience is a real boon.”

Gaël Renaux, Head of Production Facilities 1. Production facilities

“The materials processed at Tabellout are highly degraded. Crushing must therefore be adjusted to within a millimetre,” explained the international

crushing specialist who is part of the team running the Tabellout materials unit. Africa, the Far East,

Indonesia, Russia, Latin America… wherever Roger Debot has worked, this colourful adventurer

from Burgundy has left a mark on his colleagues. “I’ve seen lots of dams but this one with its arched

structure is most unusual. Its situation also demands infallible equipment and logistics.”

Roger Debot, Head of the Crushing Unit

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“The plant facilities are subject to very high wear and tear owing to the particular nature of the alluvial materials. We therefore have to stock a considerable number of spares and wear parts, but the guys always show plenty of innovation in restoring or repairing them!”

Brahim Oukheddi, Concrete Batcher

“Years later, the challenges tackled for the Koudiat Acerdoune Dam project remain in the collective memory of all of the staff, both expats and locals, who took part in the adventure. This can be seen in the fact that many of us spontaneously signed up for this new dam. Compared with Koudiat, more power must be dis-tributed as the facilities are larger and dispersed over a greater area, and the base camps accommodate more local workers. This is yet another great project for the company which confirms our earlier success in terms of RCC technology and in the completely autonomous management of a complex construction site.”

Eric Guidon, Assistant Equipment Resources Manager

Eric Guidon, Assistant Equipment Resources Manager

and Tian Rangwu, Chief Electrician.

The Electrical Department, comprising 35 people led by Chabane Choudani, assisted by Tian Rangwu and Jonathan Brisavoine, has a broad scope. It has the competence required to guarantee that the construc-tion site is totally self-sufficient in terms of power generation (11,000 kWA avai-lable power at just the dam site), 20 kV power distribution over the whole site, and troubleshooting and repair of the electrical equipment and the controllers that have become an essential part of all modern machinery.

On the strength of the Department’s great skills in all these domains, the site has the essential ability to adapt the equipment and particularly the production facilities immediately to the exacting requirements of the structure to be built, making it a pillar of the “Tabellout setup”.

2. electricity

LEXICONCVC = conventional vibrated concrete.RCC = roller-compacted concrete.

Chabane Choudani, “Kamel TRICIEN”.

Jonathan Brisavoine.


If there is another pillar of the “Tabellout setup”, it has to be the Logistics Department.At the head of a 20-strong team, Fabien Pantel is in charge of all supplies to the dam and tunnel sites, for both the Equipment Resources Department (spare parts) or Works Departments (cement, rebar, form lumber, etc.), and from all sources (Algeria or abroad).

As the supply chain is particularly long (an average of three months from placing an order to receiving the goods), there is an onsite store where a stock of commonly used products and, in particular, spare parts is kept. Almost 40,000 articles are listed and almost 20,000 kept in stock mainly due to the great diversity of equip-ment used. For many of these articles, just one piece is stocked. “This is key to the efficiency of our equipment”, explai-ned Alexis Le Guil, who is also heavily involved in logistics, even if it is not his only function in the Equipment Resources Department.The Logistics Department also deals with all issues relating to transportation, tran-sit and customs.

“And when the construction work is com-pleted,” Fabien pointed out, “barely half of the job will have been done for us, as we’ll have to re-export the majority of the equipment that we have imported.”

3. Logistics

Fabien Pantel.

The Store Team. Ahcene Gaci, Chief Storeman.

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The Mechanical Engineering Department is not exempt from the need to be totally autonomous in order to be able to react as quickly as possible in the event of a breakdown or any other requirement. A 1,000 m² workshop split between the mechanical engineering, electricity, heavy plant, machining, sheet metalwork, bodywork and painting trades accommo-dates the 60 members of the teams headed by Jean Beaufort, Sébastien Amisse, Alexis Le Guil and Mohamed Boudra. “We deal with all sorts of problems here,” Jean Beaufort explained. “We rebuild engines and gearboxes, we make parts in our machining shop where our friend Bouzid Drissi and his team work miracles every day by saving many worn or broken parts or by making new ones which overcomes the long supply time issue and saves money into the bargain.” In the adjacent unit, no fewer than five panel beaters restore cars, trucks or heavy plant that have been vic-tims of mistreatment.

“The electronics now present in all our machi-nery means that we have to be equipped with modern diagnostic instruments,” Sébastien Amisse said. Ouahid Zergat, the young elec-trician hired at the start of the Koudiat dam project who has become THE specialist in heavy plant electronics, added: “My laptop is the most important tool in my toolbox.”

The sheet metalwork trade is also very busy as even the largest excavator buc-kets are rebuilt on site, as well as speci-fic formwork and all sorts of framework and equipment to meet everyone’s needs. “The achievement we are most proud of is undoubtedly the impressive posts suppor-

4. Mechanical engineering and equipment servicing

“After 19 years with the company in France, working particularly on high-speed rail line projects, I must admit that this new experience is extremely rewar-ding. All the trades work side-by-side in an outstan-ding organisational setup in spite of the complexity linked to isolation and procurement issues.”

Daniel Rivollier, Head of Equipment Maintenance with two members of his team, Ali and Lounès

ting the Rotec,” claimed Mustapha Adi, a leading figure in the sheet metalwork shop.

The Maintenance Department is here to be counted too, with its 30 people in charge of the routine servicing of heavy plant, refuelling and, if that wasn’t enough, the distribution of fluids (compressed air and industrial water) across the site. “We are even equipped with our own semitrailers to transport the million litres of fuel required every month to run the two project sites,” Daniel Rivollier commented. “Here too, the watchwords are autonomy and inde-pendence.”

Sébastien Amisse. Alexis Le Guil. Jean Beaufort.

Left to right: Mohamed Bouchenak, Mohamed Boudra, Mohamed Hasnaoui, Sébastien Amisse and Abdelatif Boukhelf.


An immense conveyor belt transports between 1,000 and 1,300 tonnes of RCC per hour to the exact point where the dam is being built. Focus on this highly specific piece of equipment.

foCUs

AN iMPRessiVe RCC CONVEYOR

Apart from the fact that it transports concrete, what is so special about the Tabellout Dam Rotec conveyor is its ability to adapt permanently to the elevation of the dam under construction. At the site, the lowest point of RCC delivery is at elevation 211 and the highest at elevation 332 – a vertical lift of 121 metres. For this purpose, girders were required with parti-cularly long spans between bearings and thick sections, making them very heavy (113 metres and over 80 tonnes for the biggest).At Tabellout, the geology of the moun-tain upstream of the dam prevented the conveyor from being routed along the

This is Carlos Calle. This Colombian who speaks more than five languages is none-

theless a master of the understatement. He considers the Rotec conveyor to be a “very practical system”. To a novice, the famous conveyor belt that carries concrete from the production plant to

the actual dam site is an extraordinary installation. Both in terms of efficiency, of course, and also in view of its highly

improbable construction along the moun-tainside, made possible by the combined

experience of Jacky Legras and Carlos. Colombia, Brazil, Chile, Venezuela, India,

Pakistan... Carlos has worked all over the world. With his sombrero and hard hat wedged firmly together on his head, he told us: “If Razel pulls off another dam

contract, I’ll stay”. And what’s his output record? 1,400 tonnes per hour in Chile.

Hats off to Señor Calle.

CARLOS THE EXPERT

mountainside on ground-level supports as is usually the case. The outcome was a spectacular installation operation for those involved. The considerable insta-bility of the zone meant that it had to be bypassed, with a part of the conveyor being “perched” atop 20 to 40-metre pylons. Gigantic piles were made to counter the wind – which can blow quite strongly in the region – and seismic loads.The erection of heavy components (up to 80 tonnes at a height of over 30 metres) was a feat that will have to be repeated on dismantling when the conveyor will be considerably higher still. The operation promises to be even trickier.

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39

13.5 KILOMETRES OF TUNNEL

40 RAZEL-BEC / magazine No. 05 / April 2015Special Edition Destination Tabellout Tunnel

A 13.5 km transfer tunnel, 3.5 m in diameter, was originally intended to transfer water to the Sétif high plains from the dam reservoir to the pumping station. However the extremely complex subsoil has forced the project to be revised.

A CoMPLeX PROJECT

of our main constraint which is the small interior section of the tunnel which forces us to extend the length of the backup train,” commented Sylvain Mandégout, Tunnel Works Manager.After the initial adjustment phases in early 2012, the TBM quickly reached its contrac-tual cruising speed (25 metres per day) and

The tunnel is being excavated with a hard-rock tunnel boring machine to a diameter of 4.30 metres in which precast concrete segments with an inside diameter of 3.50 metres and an outside diameter of 4 metres are placed. The TBM is 236 metres long in total, including the backup train. “This considerable length is the consequence

“To overcome these difficul-ties, the Tunnel crews deve-loped methods suited to the local geological context with the backing of the support functions at head office.”

Sylvain Mandégout, Tunnel Works Manager

Sylvain Mandégout, Tunnel Works Manager

41

even peaked at over 44 metres. Record progress of 195.51 metres was achieved in the week 8–13 March 2014 and 739 metres in a month! And yet the race was by no means already won. The TBM was in fact brought to an abrupt stop as a result of a highly intense convergence* phenomenon in the surroun-ding terrain which jammed the TBM skirt (see panel opposite).

Surprising subsoil

This incident illustrates the complexity of the Algerian subsoil which continues to surprise and create difficulties. The TBM is required in fact to work through variable, hardly explored geological formations (limestone, sandstone, marl and shale with various degrees of weathering).Illustration of the same order at the dam earthwork site: a landslide on the downstream left bank resulting in a volume of material corresponding to a fifty-plus-metre slab of cliff toppling into the valley bottom. Since 29 February 2012, the TBM had only been able to make progress on 203 days, representing less than eight months’ pro-duction. The average daily production rate reached 21.95 metres, in spite of four start-up and ramp-up phases.Last June, over the whole of the tunnel excavated to date, almost half of the rings

A DISRUPTED SCHEDULE

• 9 March 2010: order to commence work.

• 27 December 2010: earthwork area of “South head” site handed over.

• 8 January 2012: TBM erection phase 1 started (shield and trailers 1 to 16).

• 29 February 2012: tunnelling started.

• 16 March 2012: TBM stopped at Point 163.82 for TBM erection phase 2.

• 31 March 2012: tunnelling resumed. 1,282 metres excavated in 2.5 months with peaks at 38.40 metres per day.

• 26 June 2012: TBM jammed at Point 1462. Significant fissuring appeared on precast segments from Point 1350.

• 1 December 2012: tunnelling resumed after releasing the shield.

By the week following resumption, major degradation began to appear on the precast segments 24 to 48 hours after the TBM had passed, whereas they were intact when they were put into place.These issues meant that the TBM had to be immobilised several days a week while the segments were strengthened by anchor bolts or by arches.

• 12 February 2013: tunnelling stopped due to suspicious movements identified in the area around Point 1575.

The TBM had reached Point 2835, so 1,372 metres had been excavated in 2.5 months since the shield had been freed, with peaks at 44.40 metres per day.

• 14 February 2013: tunnel collapsed at Point 1575.

• From 14 February to 13 March 2013: tunnel secured downstream of the col-lapse (A1198 to A1305) for safe access to the collapsed zone.

• From 14 March to 7 May 2013: collapse at Point 1575 cleared.

• From 8 May 2013 : tunnel strengthened from Point 1575 to the TBM, to secure access to the TBM.

• Tunnel strengthening continued until the rear of the TBM (A 2162) was reached on 14 october 2013.

• TBM restoration began on 12 october 2013.

• TBM restarted on 12 november 2013.

• TBM production suspended from 7 December 2013 to 2 January 2014, for the installation of a further 260 HEB-200 arches (representing 254 tonnes of steel).

• 18 January 2014, after 208.85 metres of excavation with peaks at 33.60 metres per day, tunnelling was stopped at Point 3347.02 due to another geological event which lifted the TBM and the last rings fitted.

The TBM was lifted 15 cm during the wee-kend shutdown (out of production), and the rings at the rear of the TBM were lifted 21 cm. 7 cm of displacement to the left was also observed.

• After installing major reinforcements and planing the lifted ring (to free the section of passage for the backup train), the TBM restarted on 2 February 2014,

• The TBM reached the Imnar river at Point 4483 on 1 April 2014. Excavation was suspended on the Contracting Authority’s instruction pending a decision on the solution for continuation of the project.


showed signs of degradation. In order to secure the tunnel up to the TBM, 1,214 pre-cast-segment rings had to be strengthe-ned, 2,310 arches (requiring 1,800 tonnes of steel) installed in very difficult condi-tions, 1,120 anchor bolts of various types inserted, 114 circumferential drains made, and reinforcement grouting applied to 296 points.

Reconnaissance, surveys and experimental tunnel

In order to gain a better understanding of the behaviour of the surrounding terrain and prepare a solution for the resumption of excavation, an additional reconnaissance campaign was ordered by the Employer, including topographic surface surveys, geotechnical testing in an experimental

tunnel, laboratory tests and core sampling from the surface. An airborne LIDAR sur-vey was also performed over 770 hectares between 12 and 17 February 2014. This surveying method is very quick and over-comes problems where the terrain to be surveyed is difficult to access (in our case, the steepness and safety issues prevented conventional direct measuring).An experimental tunnel is being excavated since 3 May 2014 in the existing tunnel at Point 1544. The purpose of this tunnel is to take samples of untouched terrain and carry out specific geotechnical tests which were scheduled to be completed on 10 August 2014. The following tests will be conducted to characterise the mechanical behaviour of the terrain better: plate load tests, flat jack tests and extensometer rings.

Mathias Trémolières, Head of Equipment Resources, and David Ledet, Lead Electrician, have solid background in

the construction industry and in expatriation. The tunnel equipment specialists were trained by Jacky Legras.

“After informing us, Jacky is now deforming us!”, they joked. “We mean that Jacky is not shy in transferring

knowledge and ensures that hand-overs and everyone’s integration into the team go smoothly,” Mathias pointed

out. “And this is easier said than done on a multicultural worksite such as Tabellout where some juggling was

needed so that everyone works well together. The Chinese, being willing and disciplined, have picked up

the rhythm particularly quickly”

THE SPECIALISTS

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“Originally from Sichuan, in central-western China, I have been integrated by the French and Algerian teams really well. The managers

are young, dynamic and enthusiastic. Our Head of Equipment Resources knows the whole line. He’s young and a very good boss.

Razel has really understood the challenges of multicultural worksites.”

Zhou Jun, Head of Maintenance

“Here, just like anywhere else, it’s the terrain that has the final say. If the TBM can no longer progress, I can take on jobs other than opera-ting the TBM. I was trained by the French and, in turn, I’ve trained some of them! It’s a com-pany that conveys and develops trust.”

Sofiane Bounefa, TBM Operator


The 43,000 25-cm-thick segments measuring 1.20 metres in length (four per ring) are prefabricated on site in a segment casting unit adjacent to the TBM. Production began in late 2011 as soon as the Italian-made moulds were delive-red.

A SEGMENT CASTING UNIT ON SITE

Continuing the project: the solutions

Numerous solutions for continuing the project have been studied with ANBT.The first solution is to continue under-ground.The current lining (25 cm thick) is not suited to the exceptional terrain conditions encountered. Depending on the results of the additional campaign, a new seg-ment thickness will have to be established. Providing significant alterations are made, the current TBM can be used with seg-ments up to 35 cm thick. “Over 35 cm, we have planned to use a different high-power TBM designed for high convergence

levels,” Sylvain Mandégout pointed out. According to the Consortium, changing the TBM is essential if the decision is made to continue underground. However the geological complexity is such that the investigations currently in progress cannot guarantee that there will be no further geo-logical hazards.Other solutions envisaged include the com-bined overground/underground solution, the overground-only solution or conti-nuing tunnelling but diverting the path to the east where the terrain is allegedly more favourable with less overburden.ANBT will reach a decision on which solu-tion to adopt in order to continue the pro-ject in November 2014. Frédéric Coindon,

Deputy Tunnel Works Manager

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Project DataTunnel specifications• Tunnel inside diameter: 3,500 mm• Bored diameter: 4,300 mm• Total tunnel length: 13,500 metres• Excavation by hard-rock tunnel boring machine•Precast concrete segments produced on site

Longitudinal profile• Tunnel driven uphill• Continuous 0.12% gradient

Tunnel boring machine• Single-shield hard-rock TBM• Installation of precast segments• Closed skirt• Shield length 9.5 metres• Conical shield design• Total length 240 metres

LEXICONConvergence characterises the natural tendency of terrain to close up after boring. It provides evidence of the tec-tonic forces present in the block and/or the pressure applied by the weight of the earth above the tunnel.


PEOPLE AND OCCUPATIONS

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48 RAZEL-BEC / magazine No. 05 / April 2015Special Edition Destination Tabellout People and occupations

“With administrative, accounting and cashflow services, the functions of the Administration and Accounts Manager cover a wide scope. We are the hidden face of the projects but also the point towards which everything converges. On a self-sufficient worksite such as Tabellout, and Koudiat before that, we like the production teams have to be autonomous and proactive, even if we can count on the backing of the Algiers agency and the head office’s support functions. Another less well-known aspect of the job is the management of ancillary operations such as catering. The orga-nisation of life on the worksite must be spot-on to ensure total staff satisfaction. Quality is at the heart of our approach.”

Claude Bourgis, Administration and Accounts Manager

a ViLLaGe , ON SITE

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Catering organisationIn total, on the dam and tunnel sites

• 8 base camps

• 2 food storage areas equipped with cold rooms

• 2 laundries

• 1 bakery

• 84 catering staff

Left to right: Samia Mesbout, Samira Ancel, Nacira Ancel.

Thomas Montagne, Assistant Admin & Accounts Manager

MeDiCaLSERVICESEach site has its own sick bay and an ambulance for transfers to hospital where necessary. Two medical crews, each comprising three people (a doctor, a nurse and an ambulance driver), work shifts to providing 24/7 cover.


“With local staff and expats from all over the world, this worksite’s lifeblood is multicultural. The prime asset of this complex project, from an industrial and technical aspect, lies in the high level of know-how of the teams working on it. Some of the best-qualified staff hired for the Koudiat Acerdoune project have followed the company on to this new challenge. These experienced members of staff helped pass on know-how to the new, locally hired workers at both sites. In 2014, the average local workforce across both sites totalled 1,084 people, to which we can add 57 expats. Production staff represent 94% of the overall workforce – 54% for the works, 36% for the equipment and production facilities and 4% for the operational support services (laboratory, surveying and methods). Functional support service staff represent 6% of the workforce and are assigned to administra-tive, financial, human resources, safety and general resources tasks.The staff works six days a week from Saturday to Thursday, with a continuous shift system in operation for the production teams. A staff transport service is provided between the various towns where the staff live and the two sites. In order to meet production targets, our various organisations have to be optimised, hands-on management is provided by supervisors and our human resources support teams are responsive and receptive to our operatives’ concerns.”

Joël Rémy, Site Director of Human Resources

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55

3, rue René Razel Christ-de-Saclay - 91892 ORSAY Cedex

Tél. : +33 (0)169 856 985 Fax : +33 (0)160 190 645

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