Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
  • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
  • E21D9/001—Improving soil or rock, e.g. by freezing; Injections
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
  • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
  • E21D9/10—Making by using boring or cutting machines
  • E21D9/1053—Making by using boring or cutting machines for making a slit along the perimeter of the tunnel profile, the remaining core being removed subsequently, e.g. by blasting
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
  • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
  • E21F17/16—Modification of mine passages or chambers for storage purposes, especially for liquids or gases

Definitions

• the present invention relates to a method for producing an underground gallery, or a well, for a deep installation in a geological medium intended to receive hazardous and especially radioactive waste. This process will make it possible to construct a waterproof cap during the closure of the storage.
• the future of hazardous waste has long been a problem, particularly for radioactive waste from nuclear power plants or spent fuel reprocessing plants.
• nuclear waste particularly high-level and long-lived waste
• long-term storage in a "geological" layer that is to say in deep layers of a material selected for its purpose, is envisaged. very high mechanical and chemical stability.
• the choice of these layers may vary according to the country and the site, for example to a depth of the order of 300 to 500m and in materials such as argillites, shales or granite.
• some of these wastes can create additional constraints, for example by producing heat during the first stages of storage, for a few hundred years.
• the methods envisaged for sealing are based on the filling of access tunnels with bentonite, and the sealing of tunnels by injecting a suspension of bentonite into the walls so that they resist hydraulic pressure in the case water circulation ducts.
• the stability and sealing performance for this type of storage is an important point, to prevent water infiltrations from entering the storage cells, at the risk of damaging the containers, and do not come out at the risk of contaminating the surrounding subsoil and groundwater in their underground route.
• EDZ Excavated Damaged Zone
• EDZ Excavated Damaged Zone
• These cracked areas do not always occur immediately, but develop over a period of time, depending on the nature of the environment and the depth of storage.
• Their extension can be signaled by audible crunches. For example, in the Mont-Blanc tunnel, in granite and under heavy cover, this period lasted more than a week.
• EP 1 760 256 Another solution proposed by EP 1 760 256 is to use an automated machine provided with a tool carrying arm to resize the walls to a certain thickness, to eliminate the damaged part and thus achieve a specific profile before the pouring of a concrete plug.
• this new excavation itself causes a damaged area because of the tools used, or even simply that there is a new relaxation of internal pressures that still remain behind the new surfaces exposed.
• An object of the invention is to allow a good seal to gases or liquids in good conditions of reliability and stability over time, around the galleries or wells once the plugs are sealed.
• the invention proposes a method of producing a gallery or wells in particular according to the claims below.
• the invention proposes to provide this plug in a gallery that has not been disturbed by a face size. For this, as paradoxical as it may seem, it is proposed to make part of the gallery (or well) in an area far from the face of size, that is to say, in front of the face of size.
• One principle of this method is to remove the face of size, which is the main source of damage and cracking of the host mass, the area where we must provide for the installation of a plug, or less of
• the invention proposes a method of producing a gallery leading to an underground installation intended for the medium or long term storage of hazardous waste.
• this method comprises an excavation of at least a predetermined length of this gallery by employing a method of preparation prior to digging.
• any method of prior preparation is considered unnecessary in very stable materials such as those excavated during the digging of such storage facilities.
• no reinforcement can be obtained with respect to this type of material, or only to a small extent.
• the stable and often strong nature of such materials for example granite or argillite, makes any further processing of the material before excavation difficult and expensive, in time as well as in work and equipment.
• the invention proposes to use such a method of preparation (protection and / or reinforcement), not to facilitate the construction of the gallery but to obtain a better subsequent seal of this gallery, despite the additional efforts that may represent and despite this prejudice of uselessness.
• the invention proposes to minimize as much as possible the dimensions of the holes or boreholes used to perform this prior preparation, which allows to minimize the risk of damage caused by these preliminary drilling or to avoid them completely.
• several small boreholes may be used rather than a single bore of larger dimensions, for example to excavate the volume necessary for the establishment of a prior protection in front of the face or to allow the implementation place of tie rods.
• the protective structures implanted prior to the main excavation will preferably have compact dimensions. Preferably, they will be full and it will avoid making a posteriori empty spaces or compressible inside to limit the risk of damage that could create future crash. It should be noted that this choice goes rather against the methods often used to obtain a better mechanical resistance by limiting the contribution of material, in which it is common to use or to realize hollow structures having large external dimensions
• FIG. 1 is a schematic perspective view of a multi-storage level cavities within an underground radioactive waste storage facility
• FIG. 2 is a diagrammatic view of a horizontal tunnel in the course of digging according to the prior art and of the damaged zone surrounding it, respectively in cross-section, in horizontal section, and in vertical longitudinal section in the region; the face of the waist
• - FIGURE 3 is a schematic vertical half-sectional view of a gallery portion made according to the first embodiment with prior implantation of retaining elements;
• FIGURE 4 is a schematic view of a frustoconical shell 324 constructed around a portion of the gallery of FIGURE 3;
• FIGURE 5 is a schematic horizontal sectional view of the gallery of FIGURE 3;
• FIGURE 6 is a schematic horizontal sectional view of a tunnel being excavated according to the second embodiment of the invention using consumable anchor bolts implanted alternately in three successive groups;
• FIG. 7 is a schematic view in horizontal section of a gallery being excavated according to an embodiment combining prior implantations of retaining elements a prior reinforcement of the working face by means of consumable anchor bolts;
• FIGURE 8 is a schematic view in longitudinal section of a gallery comprising a sealing plug during leak test.
• gallery is used here to indicate indifferently a horizontal gallery, or also a vertical shaft, or a descent, or also pipes at all intermediate inclinations.
• FIG. 3 illustrates a first embodiment of the invention using an implementation of retaining elements 321 to 324 before the digging of the gallery and as and when progession 219 (see FIGURE 2).
• the part 301 has already been hollowed in the conventional manner.
• the intermediate portion 302 is being excavated and is intended to subsequently receive a sealing plug.
• Part 303 is not yet dug, and will be conventionally after completion of the intermediate portion 302.
• the portion 302 is constructed sheltered frustoconical hulls 321 to 324 of horizontal axis and nested one inside the other.
• the shells already constructed 321 to 323, as well as the hull 324 under construction, are made by means of a series of boreholes 32410 made in the periphery of the face of size 309. These drillings are contiguous to each other and inclined so as to move away from the axis of the gallery to dig. They are for example dug by means of a chain mechanism, comparable to a chainsaw, but working end.
• These holes 32410 are then filled 32419 concrete to form a segment 3241 forming part of a truncated cone 324 (shown separately in FIGURE 4) surrounding an area 3240 of the future gallery.
• FIGURE 5 thus illustrates the result of the operation in a long sectional cut: the parts 301 and 303 normally excavated each have a damaged zone 391 and 393, in contrast to the portion 302 intended to receive the plug.
• the digging of the housing 3241 to receive the concrete to form the hull portion 324 creates only negligible damage, perhaps a hundred times smaller than that of the zones 391 and 393 generated by the conventional digging of the gallery.
• each of the holes 32410 made has a very small dimension which therefore causes only a very small damaged area, or none at all.
• These holes are for example of a maximum diameter of 10cm to 15cm, or even 15cm to 20cm in the case of chain drilling equipment.
• the frustoconical hulls 322, 323 and 324 have thus been entirely made in areas undisturbed by a face of size, and do not have the disadvantages of the damaged zone (EDZ) known in the current state of the art.
• EDZ damaged zone
• FIG. 6 illustrates a second embodiment of the invention using consumable anchor bolts implanted in the material in front of the face of the face and / or on its periphery, and as the progression progresses.
• the first part 601 has already been dug, in a conventional manner.
• the second part 602 is being excavated and is intended to subsequently receive a sealing plug.
• the pre-build method of preparation used herein includes the implantation of tie rods 621 to 623 consumable and sealed onto full length, to arm the front of size 609.
• These tie rods are embedded in narrow holes drilled in the front of the tail 609 and / or its periphery.
• These tie rods are for example fiberglass with a length of the order of three times the diameter of the gallery, for example between 2.5 and 4 times this diameter. They are sealed in the material of the face of size; they are distributed substantially uniformly over the surface of the face and / or its periphery.
• This armed volume may correspond to the substantially cylindrical volume of the future duct, but may also be provided to occupy a slightly conical volume widening in the direction of progression 609, at an angle of, for example, between 0 ° and 10 °.
• These tie rods strengthen the area of the face. They are of different lengths 621, 622 and 623 and implanted by successive thirds. They are destroyed during the advanced digging along the entire length of the area where we try to avoid deformation of the medium, so its cracking. New long rods are implanted by a third of the total number of tie rods each time the digging advances one-third of the length of these rods.
• a third embodiment which does not require any particular representation here, comprises the use of a method of freezing the solid mass beyond the face of the face, which allows an increase in the resistance of the medium when the interstitial water is turned into ice over ten meters in length.
• the material is then excavated in its frozen form, which prevents the formation of a damaged area around the excavated gallery.
• This freezing can be carried out with means and according to methods used in extreme cases for the crossing of an unstable zone by a tunnel. It can be done on all or part of the tunnel volume in the location of the future cap.
• the method according to the invention preferably comprises a preliminary thermo-hydro-mechanical study of the material to be digged.
• FIGURE 7 illustrates an embodiment combining prior implementations of support elements and means for anchoring the face, for example as described above.
• the anchoring means may be combined without departing from the scope of the invention.
• FIGURE 7 illustrates an embodiment combining prior implementations of support elements and means for anchoring the face, for example as described above.
• the anchoring means may be combined without departing from the scope of the invention.
• FIGURE 7 illustrates an embodiment combining prior implementations of support elements and means for anchoring the face, for example as described above.
• the anchoring means for example as described above.
• 621 to 623 may be arranged to exceed EA thickness outside the 600 series, for example to still imin the damage caused by the frustoconical hulls of drilling 321 to 323
• the invention may then include the specific use of a prior reinforcement method in certain areas of the gallery or the face when there is a greater risk of creating an EDZ.
• the invention also proposes a method for verifying the tightness of a plug, for example installed in an excavated tunnel according to the invention.
• FIG. 8 thus illustrates how to test a gallery produced according to the invention on a part 802 and comprising a plug 805 and the device for checking the tightness around the gallery.
• the tested gallery comprises the treated part 802, which has been produced according to the invention. It is located between a part 803 called upstream on one side, for example on the storage side, and a part 801 called downstream on the other side.
• a central plug 805 is made according to known methods within the treated portion 802.
• an upstream annular chamber 831 is created by installing a plug 832 d it upstream.
• an annular chamber 811 called downstream is created by installing a plug 812 called downstream.
• the upstream plugs 832 and downstream 812 may also be an integral part of the central plug 805, which then has a shape releasing an annular space forming the upstream 831 and downstream 811 chambers.
• a pressure pi is imposed in the upstream chamber 831 and the evolution of the pressure p2 prevailing in the downstream chamber 811 is recorded to evaluate the leakage rate and the leaktightness of the gallery around the central plug 805.
• Wileveau Y., Bernier F. Similarities in the hydraulic-mechanical response of Callovo-Oxfordian clay and clay boom during excavation gallery. Clays in Natural & Engineered Barriers for Radioactive Waste Confinement. 3 rd International Meeting. Lille, September 17 to 20, 2007. page 149.

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• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Environmental & Geological Engineering (AREA)
• Soil Sciences (AREA)
• Lining And Supports For Tunnels (AREA)
• Processing Of Solid Wastes (AREA)

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• 2008
  • 2008-07-17 FR FR0854876A patent/FR2934007B1/fr not_active Expired - Fee Related
• 2009
  • 2009-07-13 EP EP09737050A patent/EP2313614A2/de not_active Withdrawn
  • 2009-07-13 WO PCT/FR2009/051394 patent/WO2010007305A2/fr active Application Filing
  • 2009-07-13 US US13/054,243 patent/US20110116868A1/en not_active Abandoned
  • 2009-07-13 JP JP2011517970A patent/JP2011528119A/ja active Pending

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