Technical Field

The present invention relates to tunnels and health, environment and safety. More specifically, the invention relates to a method of building and/or operating tunnels, isolation plugs particularly feasible for utilization with the method, and uses of the isolation plugs.

Background Art

In many countries with difficult geography with mountains, ridges, fjords and rivers making road and rail constructions difficult, tunnels can represent a significant part of the infrastructure. In some areas, where the access to land is restricted or expensive due to urbanization, tunnels can result in further projects being economically viable. Tunnels are built not only for transport by vehicles and trains, but also for water supply, overflow transport, sewage transport, ventilation, for utility purpose, military purposes, and other utilization. However, the cost is often high, and meeting the requirements for health, environment and safety can cause significant challenges.

Major sources to issues with respect to health, environment and safety (hereinafter termed HSE) are from use of explosives and/or tunnel drilling machines or other typical equipment and methods. Microscopic particles, fumes, aerosols and gases from explosives, fragments from wear of machinery, components or products from fuels and lubricants can be toxic and can be fully inhaled if present in the air, which can increase the risk for serious diseases, including cancer. Larger particles, often due to challenging ground or rock conditions, can also challenge HSE seriously. Inherent inground radioactivity and/or toxicity can often be found, and when inhaled, long term exposure may result. The driving forward of the tunnel can contaminate the full tunnel volume and all technical equipment therein. Much of the technical equipment in modem tunnels are sensitive to pollution, resulting in risk for unreliability. Accordingly, due to reliability risk and HSE concern, numerous stops in progress to ensure that HSE and risk are at acceptable levels are required.

In addition, long periods with too low temperature or other unfavorable conditions for concrete curing or other typical processes taking place, can result in long seasonal stops or slow progress. In many areas, such as in Norway, the progress of the tunnel building can be seriously affected not only by concern with respect to HSE for the personnel, but also by weather and season conditions. In the winter, the tunnel driving progress can be very low or not existing. The result is slow progress in tunnel driving and completion and increased cost.

A demand exists for reducing the challenges with respect to HSE and risks for building and/or operating tunnels. A demand also exists for reduced downtime and increased progress in the process of building tunnels, which can result in reduced cost for tunnels, enabling further tunnel projects to be economically viable.

Summary of invention

The invention meets the demands by providing a method for building a tunnel, a plug for use in the tunnel, and uses of the plug.

More specifically, the invention provides a method for building a tunnel for vehicles, transport on rails, pipes or ducts or other utilization, wherein explosives, tunnel drilling machines, other tools or methods are used for driving the tunnel through a ground structure, or the tunnel is arranged through a prefabricated bore or trench structure, and wherein the tunnel comprises one tunnel bore with a ventilation channel extending from inside the tunnel at or near an active part of tunnel driving to outside the tunnel. The method is distinguished in that it comprises the steps: to arrange a plug in the one tunnel bore but with opening through the plug for the ventilation channel, whereby the active part of tunnel driving is isolated with respect to air atmosphere, and wherein the further outfitting/utility work of building the tunnel takes place in the parts of the tunnel outside the isolated active part of tunnel driving, whereby the tunnel building continues or can continue in substance uninterrupted with respect to the further outfitting/utility work, irrespective of season, weather, outside temperature and extent of pollution in the isolated active part of tunnel driving.

The invention further provides a plug to be arranged in a tunnel bore, particularly feasible for use with the method of the invention. The plug is distinguished in that comprises: an expandable mid-section, with dimension in transverse direction and/or stiffness to be self-supported from start of expansion to as installed in a tunnel bore, a peripheral section expandable after the mid-section has been expanded, and further comprising an open-close able door for personnel, vehicles or trains, arranged as an opening of the peripheral side facing a floor of the tunnel, allowing passage of personnel, vehicles or trains on the tunnel floor, wherein the plug is selfsupported by the transverse direction, that is along the tunnel bore axis, preferably by being at least 1/8, 1/6 or 1/5 of the height and/or width and/or by integrating support structure in the inner part of the plug being inflated first.

The plug of the invention overcomes operational limitations with respect to stability for easy installation and feasibility for traffic by cars, lorries, other vehicles, trains, and personnel through the plug, which are crucial factors for functionality for enabling effective building of tunnels, compared to the plugs of WO 2015/189536 A1 , WO 2015/189537 A1 and JP H05231100 A. More specifically, the plug of the inventions is not hoisted up and fastened to the roof of the tunnel when starting the installation, but is inflated from the tunnel floor by inflating the inner parts of the plug first, after which the peripheral parts of the plug is inflated, sealing the plug against the tunnel roof, whilst the plug is selfstanding and thereby self-supported during the whole installation procedure. In addition, the open-close able door for personnel, vehicles, or trains, arranged as an opening of the peripheral side facing a floor of the tunnel, is simultaneously formed during inflating the plug, without further structure between said openclose able door and the tunnel floor, allowing passage of personnel, vehicles or trains directly on the tunnel floor. Arranging or deploying the plugs thereby becomes far easier, since no hoisting/fastening operations in difficult positions are required for arranging the plug, moving the plugs as the tunnel is built become far easier, no or less work is required on the tunnel roof and sides, and storing the plugs locally is easier, resulting in far less work and possible failures, and the opening for vehicles or trains are directly on the floor enabling passing of vehicles and/or trains without damaging parts of the plug structure.

With the method and/or plug of the invention, tunnels can be built safer and faster and at lower cost, combined with improved health, environment and safety (HES) at a level higher than achievable so far. The method and/or plug of the invention enables to maintain the whole tunnel bore or bores outside the driving end(s) without fragments of explosives, oil fragments, cement/rock dust and at feasible humidity and temperature, resulting in that the tunnel outside the driving end(s) can be completed faster and to less cost. The tunnel plug of the invention enables traffic on the tunnel floor, also thorough sluices formed between tunnel plugs, and the plugs can be moved and rearranged easier, so that driving of the tunnel, outfitting and completion of the tunnel become more effective. The complete method and plug solution include systems for energy recovery and cleaning of air brought out from the driving end(s) to outside the tunnel.

Preferable embodiments of the method and plug are as defined in dependent claims and/or in the description and/or as illustrated.

A plug specifically designed and feasible for the full tunnel bore is hereinafter termed a full bore plug, whilst a plug specifically designed and feasible for cross cuts is hereinafter termed a cross cut plug, if found convenient for clarity.

Preferably, the tunnel building starts with driving one bore, with a full bore plug with ventilation duct arranged through the plug. The ventilation duct is preferably balanced, with inlet air, from outside the tunnel in a central channel and outlet air, from inside to outside the tunnel, in a channel coaxial or around the inner channel or otherwise, in heat exchange. The inlet air is thereby conditioned with respect to temperature, and favourable effect can also be achieved with respect to humidity. If the season, temperature or other factors restrict work with outfitting/utilities, a full bore plug is arranged at the inlet or in each full bore inlet, and a full bore plug is arranged near the driving end (often termed “stuff”), isolating the active driving end effectively, and outfitting/utility work can take place simultaneously in tunnel sections outside the isolated driving end or ends. If the one bore is for a one bore tunnel, driven from one or both ends, the work can continue likewise. However, a ventilation duct can preferably be arranged in a side bore/escape route. A one bore tunnel can be wide, with 1 , 2, 3, 4 or more lanes or tracks or ducts.

If a double bore tunnel is built, when the first bore has become long enough, preferably a parallel bore is driven, and a cross cut between the bores is driven. A cross cut plug is arranged in the cross cut. Then, one of the bores or an active driving end thereof is preferably kept isolated from the driving end atmosphere, for short or long time, enabling facilitating full completion of said bore or a section thereof.

Preferably, the plugs, especially the full bore plugs, can be arranged in series, as sluices, not only in either bore end, preferably as full bore plugs with fast open-close ports, allowing traffic through at least one lane or one rail, preferably two lanes or two rails. Outfitting/utilities can thereby be completed faster also in one bore tunnels while traffic still is open since sufficient ventilation for acceptable air quality can be enabled.

Full bore plugs preferably comprises fast open-close ports for vehicles, such as 5 m x 5 m or other dimension, as part of outer frame floor. Thereby, lorries or train wagons can transport excavated, drilled out or fractured ground and rock out of the tunnel bore, preferably through sluices of full bore plugs. A road-like structure, or rails, must be arranged on the lower side of the full tunnel bores, preferably at an earlier stage, for such preferred operation. Also cross cut plugs and cross cuts can comprise open-close ports for vehicles, and road structure on the cross cut floor for vehicles, enabling traffic from one bore to another, facilitating the building process.

Preferably, all plugs are built to withstand pressure variations, such as by wind and tunnelling winds, and including explosions and fire-related pressure variations. Cross cut plugs preferably comprises peripheral high friction material, such as silicon rubber coated cloth, since the smaller dimension results in lower forces than larger plugs. Full bore plugs preferably comprises high friction material and anchoring devices or fastening devices, such as fastening lugs, plugs, bolts or similar means.

Plugs with inner self-supporting expandable body with port for vehicles/trains and/or personnel towards floor as part of the peripheral structure included, and/or with transverse dimension for stand-alone functionality, facilitating installation and operation thereof, and/or with outer more flexible C-shaped ring with convex shape towards tunnel roof and sides, are preferable. The port or opening preferably is directly on the floor, with the mid-section around on three sides and the tunnel floor below without any structure of the plug below the port or opening. Preferably, the plug is self-supported in that the expandable midsection, in transverse direction, that is the direction along the tunnel bore axis, is at least 1/8, 1/6 or 1/5 of the height and/or width.

The material of the plug is in many preferable embodiments fire cloth, such as meta-aramid or kevlar, mineral fibre fabrics, or coated fabrics, or other typical fire-resistant material, but also polymer based materials are feasible. The plugs of the invention preferably are easily removable and reusable, wherein lighter polymer based materials can have sufficient strength, wear resistance, and fire or heat resistance for a prescribed acceptable period, while being low in weight and easy to install, operate, remove and reuse.

Preferably, the plug comprises a peripheral section, wherein the peripheral section preferably is a more flexible sealing element, having opposite II shape facing the roof and sides, wherein the transverse dimension of the peripheral section preferably is longer in transverse direction than the mid-section and preferably is expandable after the mid-section has been expanded. An opposite II is an II shape rotated 180°, with the concave side facing downwards. A larger transverse dimension in the peripheral section than the mid section provides better sealing. If combined with lower pressure in the peripheral section than in the mid-section, and/or material of higher friction and/or elasticity and/or puncture resistance and/or a ridge structure along the periphery, better sealing and friction can be provided.

In addition, self-supporting or self-standing functionality is preferably improved in that the mid-section, and preferably also a C-shaped peripheral section with the concave side facing downwards, comprises transverse stiffeners, such as rod elements, embedded, wherein the structure can be packed in direction perpendicular to the stiffeners, preferably symmetrically about a centre line from either side, and be expanded while being self-standing and self-supported during the full installation and operation process. The transverse stiffeners are preferably mostly or only arranged on the side facing the tunnel floor, preferably with stiffeners arranged most densely, that is with shorter distance in between stiffeners, towards the openings.

The plug expansion is by an operatively coupled compressor, compressed air or gas bank, or by sodium azide ignition.

The plug, preferably the full bore plug embodiments, comprises a frame structure towards or prearranged to the tunnel surface. Preferably, the frame structure is prearranged in appropriate positions in the tunnel, with ventilation ducts arranged outside or inside the frame structure. The frame preferably is wood, since rigidity and flexibility are favourable, and machining of openings for cables, lines, lights, and other purposes is feasible. Frame structures of wood are preferably reusable. In other embodiments, the frame structure is made of bricks, such as leca or ytong type bricks, wherein the frame structure preferably is permanent and later becomes part of for example a permanent wall with access door for personnel, leading to an escape route.

The plug and/or the method of the invention preferably comprises one or more of the features, in any combination: a self-supported door structure, a door structure fastened by magnets or other means to the mid-section, one or two expandable or inflatable parts, self-supported, between the outer frame and the door, expandable when the outer frame and door is arranged, wherein the parts are the mid-section and the peripheral section, a wooden outer frame, massive wood or preferably glue laminated and/or cross laminated timber/wood, with machined openings arranged for cable ducts, lights, power or/and instrumentation cables or pipes, which wooden outer frame is reusable or is a fundament for later use in the tunnel, which wooden frame preferably at least faces the roof and sides of the tunnel bore, a door or port for vehicles and/or trains, open-close able upwards or sideways, automatically when traffic accumulates and/or opening and/or closing as controlled by an operator, and/or a remote control mechanism, a more flexible centre part of the peripheral opposite U-section, facing the tunnel bore or an outer frame, for example comprising less fire resistant material than the sides parts and/or having an outer ridge along the periphery, a more flexible centre part on the mid-section and/or ends of the peripheral part facing the driving lane or rails or floor, for example comprising less fire resistant material than the sides parts and/or having an outer ridge along the periphery, pads for fastening fire cloth on at least one or both of the sides facing the tunnel bore, thereby improving fire resistance significantly, also for plugs made of inflatable polymer cloth, one or more openings, preferably along the periphery, for one or more ventilation ducts, preferably the ventilation ducts are coupled to an air cleaning facility at the outlet outside the tunnel, one or more anchoring devices, such as anchoring lugs, openings for anchoring bolts or other means, along the periphery, for withstanding pressure fluctuation, such as by explosives, for the one or two full bore plugs nearest to the driving end, if tunnel driving is by explosives, the plug or plugs preferably are over dimensioned with respect to anchoring lugs, openings for anchoring bolts or other fastening means and/or over dimensioned in the opening with respect to robustness and functionality for robust and fast open and close function for traffic by vehicles or trains transporting out rock fragments, for withstanding the explosions when arranged as a single full bore plug or two full bore plugs arranged as a sluice, which provides a unique functionality for tunnel driving rate and simultaneous outfitting of the tunnel parts outside said plugs, arranging full bore plugs at intervals so as to reduce flow of air velocity through the tunnel bore so as to enable concrete spraying without concrete dust problems and allow temperature to adjust to the natural rock temperature, in Norway 8- 10° C any time of the year, thereby enabling ideal work conditions for completion and outfitting any time of the year. The invention also provides use of the plug of the invention, for improved HSE and/or increased technical reliability when building tunnels, as temporarily or permanent cross cut isolation plugs, as end plugs and/or sluices in main tunnel bores; as isolation plugs for facilitating escape in case of accidents or fire; for isolating fire extinguishing gases into a tunnel bore volume between plugs; as barriers for better protection of shelter (escape rooms), such as for closing tunnels leading to subway stations, train stations and other rooms underground or over ground being feasible for escape and accessible via tunnels or similar routes that can be closed or restricted by plugs of the invention for improved air quality and/or shocks.

Brief description of drawings

Figure 1 illustrates an embodiment of the method and plugs of the invention,

Figure 2 a-d illustrates a main embodiment of a plug of the invention,

Figures 3 a-d illustrates a main embodiment of a plug of the invention.

Detailed description of the invention

Reference is made to Figure 1 , illustrating an embodiment of the method and plugs of the invention, more specifically a section of a double bore tunnel 1 with cross cuts 2, with a cross cut embodiment of plugs 3 of the invention arranged in cross cuts and a main bore embodiment of plugs 4 of the invention arranged in the main tunnel bores. The driving end 5 of one bore (stuff) is in black, the cross cut plugs 3 are yellow/light grey and the main bore plugs 4 are red/dark grey. An additional access/air in-air out tunnel 6 is also illustrated. The illustrated part is only a section of a much longer total length, in either end. What is not illustrated is that in each main bore, a ventilation duct is arranged, transporting air from the isolated driving end inside the plugs to outside the tunnel bores. In the bore with the driving end, ventilation ensures a little underpressure, preventing leakage of polluted and perhaps toxic air and fumes to the other bores. The severely pollute and perhaps toxic air is ventilated out through a ventilation duct in the bore with the driving end. In other preferable embodiments, a fill bore plug is arranged near the driving end, and preferably with further plugs, providing sluices and cleaner air in further parts of the tunnel system from an earlier stage.

Further reference is made to Figure 2 a-d illustrating an embodiment of a plug 3 of the invention, to be arranged in cross cuts, and termed a cross cut plug. These embodiments are smaller in dimensions than the main bore plugs, since the bores are smaller in diameter/height/width and often without opening for allowing traffic by cars, lorries or other vehicles, or trains, to pass through the plugs. However, the cross cut plugs 3 comprises opening 7 or openings for access of personnel and optionally other equipment, such as optional ventilation ducts or access for fire hoses, cables and lights. Figure 2c illustrates a pad for fastening fire resistant cloth, illustrated as detail 01 on Figure 2a. Figure 2d illustrates a magnetic strip for hanging up door cloth, illustrated as detail 01 in Figure 2a.

Further reference is made to figures 3 a-b illustrating a main embodiment of a plug of the invention, more specifically a main bore plug 4. These plugs are arranged in the main bores, with ventilation ducts typically arranged on the outside or through the plugs, and typically including a port for vehicles and/or trains, allowing traffic and equipment to pass through. Such plugs and arrangements thereof are very preferable for allowing enhanced progress. Waste material/rock fragments can be transported through the ports in the plugs, on vehicles and/or trains, preferably with the plugs arranged as sluices for maintaining a cleaner air quality outside the sluices despite traffic and frequent opening and closing. When the tunnel has been built with at least one bore through the full length, traffic can start earlier than common practice, while the total time and cost for building a double bore or single bore traffic is significantly reduced. A saving in cost of from 10% to over 40 % is realistic, according to estimates and tests. A saving in time up to above 50% can be achieved in the best estimates, which represent a significant advantage for the society.