LAGUNA-LBNO at Fréjus General Meeting September 2013, Paris Giovanni Como and Davide Vietti

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Contents List of contents: Access tunnel cross section choice: - considered parameters - comparison between different options - identification of the final choice Access tunnel portal area (legal permits and occupation of external areas): - peculiarities of the chosen entrance areas Excavation of the main caverns: - excavation technique - safety aspects - ventilation management - linings and expected deformations Open Questions Future steps

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice ASPECTS TO BE CONSIDERED: Building site ventilation (minimum required air exchange) Safety during construction (fire loads to be considered) Logistic during construction Logistic at final operation stage (transport of PMTs and of different parts of the future laboratory) Safety at final operation stage

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects BUILDING SITE VENTILATION REQUIREMENTS: Access tunnel construction: ventilation will be managed according to normal AFTES prescriptions for tunnel excavation Maximum volume of the caverns: x 2 = m 3 Maximum air speed in accessible ducts/tunnels = 5 m/s Maximum air speed in non accessible air-ducts = 20 m/s Optimal air exchange rate during construction phase = 2 vol./hour

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects REQUIRED CROSS SECTION CALCULATION: In any case it will not be possible to refresh the air simultaneously in both caverns. Thus the following calculations will be made referring to the volume of just one cavern.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects REQUIRED CROSS SECTION CALCULATION:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: HORIZONTAL SLAB OPTION: Solution presented in Hamburgh ( ):

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: VERTICAL WALL OPTION – NOT OPTIMIZED SECTION:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: VERTICAL WALL OPTION – OPTIMIZED SECTION:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: DOUBLE TUNNEL OPTION – SOLUTION 1:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: DOUBLE TUNNEL OPTION – SOLUTION 2:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects DIFFERENT CONSIDERED OPTIONS: DOUBLE TUNNEL OPTION – SOLUTION 3:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Ventilation aspects COMPARISON IN TERMS OF AVAILABLE CROSS SECTION FOR AIR FLOW: Referring to the proposed cross section schemes the option with a horizontal slab results to be more efficient for little air flow rates For rates around 200 m 3 /s the options of a double tunnel and of a single one with a horizontal slab have the same efficiency To guarantee higher flow rates (> 200 m 3 /s) the more efficient solution feasible with usual excavation and support techniques is the one with the vertical slab

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Logistic aspects CONSIDERED ASPECTS: the chosen cross section must guarantee the possibility to install a material transport system based on electric trains A conveyor belt will also be installed There must be the possibility to access the tunnel with heavy trucks for special transports (minimum loading gauge h = 5.0 m – w = 3.75 m)

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Costs aspects COSTS COMPARISON: The unit costs considered for the comparison are based on the Lombardi SA experience of similar tunnel shapes in Europe Referring to the proposed cross section schemes the option with a horizontal slab results to be less expensive than the solution with 2 tunnels for air flow rates around 200 m 3 /s The solution with a vertical wall for an air flow rate of around 200 m 3 /s has a comparable cost and a slightly higher efficiency

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice CHOICE OF THE BEST OPTION: The cost estimation is based on unit costs derived from Lombardi SA experience on projects realized in Switzerland (real prices applied by Construction Companies) The option with the vertical wall guarantees the same air flow rate of the horizontal slab option with a reduced cross section (it is not necessary to build the final lining to install the slab) thus reducing the final cost The option with 2 separate tunnels results more expensive due to the 2 different excavation techniques to be adopted on the same building site. The length considered in calculations already takes in count the bifurcation to reach the caverns top.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice CHOSEN CROSS SECTION: Possibility to have an efficient logistic both during the building phase and in the future laboratory activity one. Possibility to have a separated escape-way

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Alignment solution 1 Solution N°1 - New access tunnel Tunnels total length [m]7035 First estimation of the volume to be excavated [m 3 ]471345

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel cross section choice – Alignment solution2 Solution N°2 - New access tunnel Tunnels total length [m]6990 first estimation of the volume to be excavated [m 3 ]468330

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel entrance areas National Road RN 46 Solution N°1 Tunnel Frejus Platform Solution N°2 Landfill site of Frejus Safety’s Tunnel City Road Road Modane- Frejus Tunnel Site Construction Road Existing Tunnel Tunnel under construction Possible entrance areas illustrated in Hamburg

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel entrance areas SOLUTION 1: current muck storage area Current storage area of Frejus safety tunnel muck PRO : access without entering the Modane village good distance from the residential area CON : probable litlte storage volume available

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Access tunnel entrance areas SOLUTION 2: old quarry area Current storage area of Frejus safety tunnel muck PRO : good residual storage volume CON : to avoid the access through the Modane village the narrow connection between Sol 1 and Sol 2 must be enlarged.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Construction permission Procedure: Submission of the form for the construction permission to the municipality Publication of the construction request (3 months) In case of no opposition, the request will be allowed In case of opposition, the request can be refused ( PRO : The chosen areas are currently being used for muck storage and construction activities, thus are not residential or agricultural areas.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Aspects of fire safety Considerations: According to Lombardi SA experience there are no Regulations defining the fire loads to be considered during the building phase of underground structures. The power connected to the fire of a car or a truck varies between 5 and 15 MW. As a term of comparison the power involved in the channel tunnel fire was estimated into 350 MW, while the one in the Mont Blanc tunnel reached about 175 MW. PRO : the power involved in a fire during the construction phase is stronghly lower than the one of a destructive fire. Fire situations are usually managed during underground structures construction. Channel tunnel fire.Mont Blanc tunnel fire.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Aspects of fire safety Possible risk-mitigation measures: Examples of refuge and rescue chambers. These chambers will be used after blasting during the smoke evacuation phase. Fire safety will be guaranteed by: - Instruction/training of the workers - Monitoring systems - Design of the electro-mechanic equipments

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Update of the final layout in the caverns area Possible optimizations and solutions:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Update of the final layout in the caverns area Possible optimizations and solutions:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Aspects connected to the caverns excavation phase POSSIBLE SOLUTION FOR MATERIALS AND EQUIPMENTS HANDLING DURING CAVERNS EXCAVATION:

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Aspects connected to the caverns excavation phase POSSIBLE SOLUTION FOR MATERIALS AND EQUIPMENTS HANDLING DURING CAVERNS EXCAVATION: Top-hammer drilling rigs for vertical drilling (total weight ≈ 20 t) Muck evacuation through a vertical shaft. Technique commonly used in caverns excavations. (Kops II power plant cavern) Scheme of ventilation and muck evacuation. Muck evacuation through a vertical shaft. Technique commonly used in caverns excavations. (Kops II power plant cavern) Monorail crane

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Choice of the final lining system for the caverns The considerable thickness of the concrete linings and the consequent volume will imply the development of shrinkage deformations. Considering an average value of shrinkage deformation  = ‰ and an average lining radius of m the expected deformation due to shrinkage varies between 4 and 6 cm on the whole circumference. Such a deformation, without the presence of any construction joint or adequate reinforcement, will cause the formation of an uncontrolled concrete cracking. As presented in Hamburg, starting form the experience coming from the hydraulic, Lombardi SA proposes to create a lining with construction joints. The thickness of the lining will be variable between 1.5 m (top) and 2.3 m (bottom)

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Choice of formwork system for the final lining – Self climbing formworks Connectors between the formwork and the concrete wall The formworks can be adapted to curved or straight shapes The formworks are connected to the already cured concrete with connectors with a resistance between 150 and 220 kN The formworks can be self climbing with a system of hydraulic motors acting on racks or in alternative they can be lifted by cranes

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Chosen solution for dome support Permanent for the systematic bolting The dome support will be realized only with shotcrete (reinforced with steel fibres in the first 5 – 10 cm and then steel welded mesh. The rock bolting will be realized with permanent anchors able to bear the rock- mass loads during the entire service life of the laboratory.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Frejus – Rock-bolting solutions Strand anchors installation Strand anchors for the vault stability

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Frejus – Rock-bolting solutions

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Fastening of the photomultiplier panels Yann Colaitis – APC Laboratory SUPPORT STRUCTURE: Horizontal stability elements Technodyne International Ltd. QUESTION: will it be possible to have a fine regulation system on the PMT’s support system in order to compensate unavoidable construction deviations from the theoretical shape (± 5 cm) and to compensate the time dependent lining deformations?

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Open questions for Partners Which is the accepted tolerance in the civil works dimensions? A common tolerance of ± 5 cm could be accepted? Rock-mass time dependent deformations, in particular in the tank caverns, can not be excluded. Which are the maximum allowable deformations? Are there any purity demands also for the civil structures? During the construction phase is it necessary to consider particular measures to keep air, water and realized structures clean? Is it acceptable to have a temporary variation in the stored liquid temperature? Which is the maximum allowable variation? Is it possible to quantify the final installations in the new access tunnel connected to the future laboratory activity: number of optical-fibres ducts, number of independent power supply cables, number and dimensions of ducts for possible special liquids supply, etc.? It is important to know the minimum required areas for PMT’s storage during installation. Quantification of radon emissions in Frejus massif.

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 Fréjus Open questions Construction permits: procedures to be cleared soon Water supply: contacts with Val Susa authorities are ongoing Technical aspects sprayed waterproofing membrane Final cost estimation after answers to the actual and future technical questions

LAGUNA-LBNO at Fréjus – General Meeting, Paris, 16 – 18 September 2013 END THANK YOU FOR YOUR KIND ATTENTION