CN116113754A - Tunnel shield - Google Patents

Abstract

Tunnel Boring Machines (TBMs) are known which comprise a large metal cylindrical shield in front of which is a rotary cutting wheel and which contains a tunnelling chamber in which the excavated soil is stored (and optionally mixed with mud for extraction, depending on the type of geological/soil conditions). However, TBMs suffer from various drawbacks, including their start-stop characteristics for tunnel excavation, and the inability of individual TBMs to easily transition between different rock/soil types (especially severely crushed and sheared rock formations). The present invention provides a tunnel shield provided with a jet grouting tool arranged to protrude from a leading edge thereof. In this way, the quality of the geological material that is excavating the tunnel may be dynamically improved as part of the excavation process.

Description

Tunnel shield

The present invention relates generally to tunnel shield and finds particular, but not exclusive, use in constructing tunnels that are several kilometres long.

Tunnel Boring Machines (TBMs) are known which comprise a large metal cylindrical shield in front of which is a rotary cutting wheel and which contains a tunnelling chamber in which the excavated soil is stored (and optionally mixed with mud for extraction, depending on the type of geological/soil conditions). Behind the heading room is a set of hydraulic jacks for advancing the TBM relative to the concrete tunnel wall behind. As the TBM moves forward, the tunnel wall is installed in segments. Once the TBM has excavated a length it is stopped and the installer builds a new tunnel ring using the precast concrete segments. More operators can be found behind the shield, in the tunnel-finishing section, which are generally considered as part of the TBM system: decontamination, mud plumbing (if applicable), control rooms, tracks for transporting prefabricated pipe sections, and the like. However, TBMs suffer from various drawbacks, including their start-stop characteristics for tunnel excavation, and the inability of individual TBMs to easily transition between different rock/soil types (especially severely crushed and sheared formations).

According to a first aspect of the present invention there is provided a tunnel shield comprising: a movable protective structure for use during tunnel excavation, the movable protective structure being configured to protect an interior region thereof from tunnel collapse; at least one guiding probe arranged to extend from the leading edge of the mobile protection structure into the geology of the tunnel to be excavated; and a jet grouting tool located on the at least one guiding probe, the jet grouting tool configured to pour slurry into the earth to enhance its quality.

Thus, as part of the excavation process, the quality of the geological material that is excavating the tunnel may be dynamically improved.

Pressure grouting and jet grouting are known techniques in which a slurry is poured into a geologic material (e.g., soil, sand, and/or rock) to enhance its quality, such as to correct faults, enhance its strength, and/or reduce the flow of water therethrough. Such grouting techniques are commonly used around the foundations of large structures (buildings, bridges, etc.) and around underground structures including large pipes and tunnels. Typically, in pressure grouting, a slurry is poured into the geologic material to fill any interconnected voids and interstices, so as to stabilize the existing material without disturbing it. In contrast, jet grouting is typically accomplished by relatively high velocity grouting jets, which serve to erode and significantly mix the geologic material in situ, and generally form a specific shape (e.g., column and/or platform).

The protective structure may be hollow and/or may comprise an outer shell and an inner void, in which the machine (which may also form part of the tunnel shield) may be located. The protective structure may be substantially tubular; i.e. having a wall extending substantially along its axial length. The walls may extend different distances depending on their height (along the axial length). For example, the top of the structure may extend farther than the bottom of the structure such that it overhangs the bottom to allow operation below it (or above it if the top extends far less than the bottom). Alternatively, the walls may extend the same distance such that the structure is substantially prismatic in shape (but has open ends for operation).

The invention can be used for building new tunnels, as well as for expanding and/or replacing lining and/or repairing existing tunnels.

The tunnel shield may be used in situations where a first hole along a first predetermined path is drilled through the earth. The diameter of the first hole may be significantly smaller than the diameter of the tunnel to be excavated, for example at least ten times smaller, in particular at least twenty-five times smaller, especially at least one hundred times smaller. A plurality of second holes may be drilled through the geology along respective second predetermined paths, each of which may be substantially parallel to the first predetermined path so as to define a substantially prismatic region therebetween. That is, if an imaginary plane connecting each hole to each other is provided, the outermost imaginary planes may collectively define a boundary surface forming the prismatic region. All cross sections of the prismatic region perpendicular to the drilling direction may be identical. If such a cross-section is taken at any point along the length of the prismatic region and an imaginary line is provided connecting each aperture to each other, the outermost imaginary lines may together define a boundary polygon.

Such drilling may include directional drilling, such as HDD or the form of directional drilling used in the oil and gas industry. In addition, there are various directional drilling techniques for the mining, oil and gas and construction industries. For example, horizontal Directional Drilling (HDD) is used for installing pipes and the like. HDDs are capable of drilling holes with adequate precision, up to only about 800m, and diameters between 100mm and 1200 mm. Alternatively, directional drilling is used in the oil and gas industry, and longer holes may be drilled.

The drilling operation may be performed from the entrance and/or exit of a pre-built tunnel, from a centrally located shaft and/or from the ground. Alternatively or additionally, the drilling operation may be deployed from the tunnel shield. Directional drilling/boring techniques may be combined with shield techniques such that boring is performed from each steering probe on the shield, allowing the shield to advance before boring is complete.

Each of the first and/or second plurality of holes may comprise a hole and/or shaft having a substantially circular cross-section and a length several orders of magnitude greater than its diameter. For example, the diameter of each hole may be between 100mm and 1200 mm; the length of each aperture may be at least 25m, at least 50m, at least 100m, at least 200m or more.

The method may include determining a first predetermined path (and optionally a second predetermined path); however, this will be done by conventional methods.

The generally prismatic region may be defined by the second plurality of apertures alone or may be defined by a combination of the second plurality of apertures and the first plurality of apertures together. For example, a combination of the first hole and the two second holes may form a triangular prism-shaped region. For another example, three second holes may individually form a triangular prism-shaped region in which the first holes are located. Alternatively, if three second holes and first holes are properly positioned relative to each other, the three second holes and first holes may form a cubic (square prism) area.

The prismatic region may be curved; that is, the region may have a cross-section of a regular or irregular geometric shape (e.g., triangle, square, etc.) along its entire length (and the geometry and the size of the shape may be constant along its length), however, the path on which the region is based may not be a straight line, but may be a curve.

The first aperture may comprise a single first aperture or a plurality of first apertures (e.g. two or three first apertures). The first hole may include a guide hole. The guide hole may be spaced apart from the periphery of the prismatic region, positioned through the interior of the prismatic region.

Data from the first hole may be collected to determine the material from which drilling has been performed.

The plurality of second holes may form a tunnel profile; that is, the plurality of second paths may protrude along the wall of the planned tunnel. For the avoidance of doubt, during construction other holes may be formed which do not contribute to the tunnel profile or to additional and/or different tunnel profiles.

The tunnel cross-section may be circular; however, other cross-sections are also possible (preferably non-circular cross-sections), such as rectangular, semi-circular, arched, flat bottom, etc. A rounded or curved wall may enhance the stability of the tunnel structure so formed, but it is not deemed necessary (e.g., based on data obtained from the first/second apertures), and a flat floor may be selected to facilitate movement of personnel, excavating equipment and muck trucks, and/or to suit the end use of the tunnel (e.g., as a road or railroad track).

The first and/or second apertures may be lined with, for example, a (e.g. sacrificial) tube or lining. In this way, the integrity of each hole may be protected. The first holes may be lined before/after drilling of the plurality of second holes is started and/or completed. Similarly, at least one of the second holes may be lined before/after drilling of the first holes begins and/or completes. Lining may include lining the entire hole, or lining only a portion of the hole. Any hole liners may be removed or partially removed prior to excavation.

All or part of the first and second holes may be drilled simultaneously or each hole may be drilled separately. This may be particularly important when drilling holes in sand/soil where the integrity of each hole is compromised.

A tunnel shield is utilized to excavate material within the substantially prismatic region to form a tunnel.

The shape of the shield and the outline of the tunnel; i.e. the cross-section of the area to be excavated is matched. The one or more guide probes may be sized to fit within the first and/or second apertures; in particular, the one or more guiding probes may be dimensioned to allow the position of each hole to vary somewhat from its intended path, for example up to 50cm, more particularly up to 30cm.

The guide probe may be configured to guide the shield into position. In particular, the guiding probe may be arranged to extend into the bore such that the positioning of the shield may be controlled and/or monitored.

One or more of the steering probes may be retractable and/or removable. In this way, the out of tolerance stretching problem can be addressed by temporarily retracting/removing the associated guide probe (until re-engagement is possible) and digging through an alternative means (e.g. boom mounted cutter blade found on a heading machine).

One or more of the guide probes may be retractable so that the guide probes may be removed or the tool replaced without moving the shield.

The at least one steering probe may comprise only one steering probe or a plurality of steering probes, for example two, three, four, five, six or more steering probes.

Some or all of the guide probes may be arranged on the protective structure such that they are aligned with respective ones of the first and second plurality of holes.

A plurality of guide probes may extend outwardly from the protective structure. The leading edge of the protective structure may be the edge of the front of the structure during use and when moving into the tunnel and/or the geology to be excavated.

The geological or geological material may be any form of subsurface (e.g., subsurface) material that is being (and/or is to be) excavated into a tunnel, such as rock, soil, sand, gravel, and/or other alluvial deposits.

The jet grouting tool may be configured to supply materials that may include grouting and/or remedial substances, such as epoxy, polyurethane foam, polyurethane resin, acrylic, cement, and aqueous solutions. The grout may be cement, resin or a solution chemical mixture. The grout may be cement, resin or a solution chemical mixture.

The tunnel shield may be configured to deposit the reinforcing member into the material poured during jet grouting, which may include a region within the bore. Thus, the tunnel shield may further comprise an insertion device for deploying the stiffening element. The reinforcement member may be configured to act as a tensioner within the grout to strengthen and assist the grout under tension. The reinforcing member may include a reinforcing bar; i.e. a metal (e.g. steel) rod (e.g. threaded or unthreaded) and/or a wire mesh. Alternatively or additionally, the reinforcement member may comprise a cable and/or a cable bolt.

The tunnel shield may be shaped so that it conforms to (and/or approximates/substantially conforms to) the cross-section of the prismatic region. For example, if the prismatic region is substantially regular octagon in cross-section, the tunnel shield may have a rounded (or octagon, or any shape therebetween) leading edge.

The protective structure may be movable in that it may be moved along its axis by internal or external means. I.e. it can be moved along the tunnel to be excavated.

The tunnel shield may include an internal/external power motion source (e.g., a motorized drive wheel or track) that may be used to initially align the device with the start of the tunnel face at the beginning of the excavation and/or during the excavation if the tunnel shield is to be diverted and/or realigned.

The shield may comprise a dragline shield, and the method may further comprise pulling the shield through the material. The dragline shield may be a combination of conventional tunnel shield and dragline excavator technologies such that the tunnel shield includes cables/ropes/chains (typically controlled by a winch) that may be used to drag the protective structure. The cable/rope/chain may pass through the first and/or second apertures) but does not require a positioning arm because the dragline shield is located within the tunnel and does not require positioning.

The dragline shield may be pulled through the material by a plurality of cables, each cable of the plurality of cables passing through a respective hole of the first and second plurality of holes.

In this way, the progress of the shield can be reliable and continuous. Each cable may be attached to a respective steering probe. One or more winches may act on respective ones of the plurality of cables or on more than one of the plurality of cables to pull the shield forward. The winch may be disposed at an opposite end (e.g., an open end) of the bore.

Each cable may be independently controlled such that a different amount of tension in each cable may be used to effect manipulation of the shield. The respective tension may be determined by monitoring the position of the respective probe relative to the hole in which it is located; however, other methods of determining tension may alternatively or additionally be employed, such as monitoring the position of the support structure. Such monitoring may be performed manually and/or automatically using sensors and/or control systems.

Each of the plurality of cables may pass down through a respective one of the first and second apertures to a cable return bracket secured downhole and up through the respective aperture back to the dragline shield.

In this way, the winch may be positioned behind or within the shield and shield operations may be initiated before each hole is completed.

The cable return bracket may include a clamping system that engages the bore wall and is disposed within the bore. The clamping system can be remotely operated to engage and disengage on command so that it can be moved to a new position when required.

The excavated waste soil may be continuously removed to the loading mechanism, for example, with a mechanical excavator. However, in a preferred embodiment, the shield is shaped such that the shield moves forward through the excavated tunnel lifting the excavated waste soil onto the loading mechanism. Specifically, the action of lifting the excavated waste soil is similar to a bulldozer or a dragline bucket.

The excavated waste soil in the shield can be removed by a conventional method; the excavated waste soil has been transported back to the tunnel floor where it can carry heavy machinery. Heavy machinery may include zero emission autonomous electric or hydrogen powered transportation vehicles. These vehicles may carry material, such as transporting prefabricated lining segments (if used) to the work area and taking away excavated waste soil. The vehicle may be configured to automatically return to the charging point as needed prior to resuming operation.

The lowermost hole (e.g., along the tunnel floor) may be cleaned (e.g., with a sweeper) behind the point where the excavated waste soil enters the shield so that the landing gear (e.g., wheels/skids) of the shield may be advanced from the sacrificial lining over the roughened half-pipe. In this way, no track need be installed or extended as the shield advances.

Loose debris may be scooped up and removed by a sweeper and conveyor belt (which may form part of the tunnel shield) which conveys material to the rear of the protective structure for removal from the tunnel. Tunnel shields may include heading machines, backhoes, and similar machines built into the front of the structure, for example, to assist in breaking up material and moving it onto a conveyor system. The machine may be controlled by an operator outside the tunnel, for example using a camera, lights and radar/lidar scanning system which communicate with a control room located outside the tunnel, allowing the apparatus to operate unmanned on board to ensure safety. The shotcrete lining may be automatically delivered using a machine mounted at the rear of the protective structure. These devices may be directly connected to the protective structure and/or may be mounted to the trailer immediately behind the protective structure. Alternatively or additionally, the tunnel shield may comprise robotic rock bolting means and/or concrete slip forming means in a similar manner.

Operations of the shield may include lining the tunnel while excavating the tunnel; for example, as the shield moves forward, the tunnel may be lined up directly behind the shield.

Tunnel lining options include precast concrete blocks (with or without waterproof lining), cast-in-place concrete (e.g., modular blind design forms involving the use of rebar), and/or shotcrete, such as "shotcrete" (with or without sprayed waterproof film, optionally in combination with roof anchor supports, wire mesh, or rebar/rebar).

It is contemplated that the present invention may also be used with timber, masonry, block, masonry, tunnel process piping and/or tunnel lining of cast steel/iron pipe sections.

For example, the formation of tunnel lining may include spraying a waterproofing membrane (e.g., basf (RTM) spraying a waterproofing membrane to form a continuous waterproofing system and formulated for use in conjunction with shotcrete and cast-in-place concrete to facilitate construction of composite structures) and internal spraying of fiber reinforced concrete. Alternatively, if the geology requires higher structural integrity, the cast-in-place approach may be preferred.

The operation may also include a continuous concrete forming process. In particular, as the shield advances, the last of a series of sequentially reusable metal formers may be moved forward, with the older concrete having set and being in front, where casting will continue in a nearly uninterrupted process. Water and cement may be brought into the working area and the excavated aggregate may be used, where possible, to mix the concrete locally during the excavation operation. The former is expected to be about 10m in length, 3 or 4 blocks per section, and to have 10 or more sections in use. This means that a tunnel of about 90 metres behind the shield will have a former in place with fresh concrete poured in front and solidified concrete behind, where the front pipe section is removed and advanced in a continuous cycle. The former can pass each other so that the unit where the earliest and already set concrete is located can be moved forward for redeployment at the front end of the process. The seal between the former and the surface of the concrete to be poured may be made with a pneumatic gasket. Once the latest model is placed and the gasket is inflated, the previous gasket will be deflated so that the casting remains continuous. The process may be simply repeated.

The waste earth from directional drilling and excavation can be used to make concrete that can be pumped into the space between the tunnel skin (if prefabricated lining is used) and the outer shell to fill the void therebetween and further stabilize the structure. Alternatively or additionally, such excavated waste soil (e.g., rock detritus) may be used as part of the aggregate required to make concrete in situ to form tunnel lining using removable and reusable forms or other lining methods, such as shotcrete.

A flat ground can be poured in a continuous operation as the shield is moved forward and the metal plates or structures protect the concrete as it sets. The shield may utilize some directional drilling of the tunnel bottom as a guide rail or track (the required number is determined by the shield design). Once all tunnel excavation work has stopped and the shield has been removed, these can be filled or will be reused.

One or more guide probes or one or more additional guide probes may be provided with (optionally exchangeable) tools allowing to dig them out from within the first and/or second holes. In particular, various different tools such as a disk cutter, a rotary cutting cylinder or cone cutter, a chainsaw arm with teeth adapted to the material being treated, high pressure water, plow blades, acoustic fracturing techniques and hydraulic separators may be employed to treat different materials, which may apply tremendous pressure around and within the tunnel as needed to further loosen and break up the material to be removed.

Some or all of the tools (including the jet grouting tool) may be located on at least one of the guide probes; that is, it may be mounted in front of the guide probe (i.e., at the opposite end of the guard structure from the leading edge). Alternatively or additionally, the tools may be mounted on one side of the steering probe, or may be attached to the steering probe so that they can be operated remotely similar to conventional downhole drilling equipment.

One or more tools may be activated simultaneously with each other or may be activated independently.

Collapse techniques may be used for soft and/or loose materials to be excavated. For this type of operation, the pilot probe may be equipped with a coulter and/or reaming tool as the shield is advanced.

As the shield advances, the newly exposed outer surface of the excavation can be continually scanned using a laser array to ensure that no material protrudes from the peripheral wall into the tunnel, thereby contaminating or impeding advancement of the shield. Ground penetrating radar (or other such remote sensing technology) may also be used where excavated waste earth covers the just exposed tunnel area.

The method may also include removing these areas when they are detected, for example by using a robotic arm fitted with a pneumatic drill or interchangeable cutting head or other suitable tool.

The shield may have a beveled leading edge, the angle of which may be selected by conventional methods depending on the nature of the material to be excavated. Specifically, the sloped leading edge slopes upward and toward the tunnel to be excavated.

The shield can be pushed by a hydraulic cylinder.

Either or each aperture may be lined with a gasket. The lining may comprise a sacrificial lining. The lining may comprise a solid wall. Alternatively, the lining may be pre-perforated; in this way, time and cost spent in the field can be saved with sufficient knowledge of the underlying geology. The pre-perforated lining may include an outer sleeve covering the perforations; thereby, material or water can be prevented from entering the pores in an uncontrolled manner.

The apparatus may be passed through the lining in a conventional manner to perform operations at the desired location. The apparatus may include a return carrier, a drill bit, and/or a perforating gun. In particular, perforating guns (as are conventionally used in the hydraulic fracturing industry) may be passed through the liner to perforate the liner at the desired location. The perforating gun may include multiple shaped charges, one or more drill bits, one or more blades, one or more needles, and/or other suitable devices for perforating a tubular wall. The perforating gun may be configured to weaken the material outside the lining; i.e. the explosive may fracture the material. Perforations may be formed in desired locations on the lining, such as facing inwardly toward the prismatic region, facing outwardly away from the prismatic region, and/or lying laterally along the outline of the prismatic region.

The underlying geology may be treated prior to excavating the material to increase the efficiency of excavating the material.

The treatment may include acoustic and/or hydraulic disruption of the material within the substantially prismatic region.

In the case of a relatively hard material in this region, the material may be ruptured by introducing pressurized water, for example, through perforations. Unlike hydraulic fracturing operations that remove natural gas or oil, small particle hydraulic fracturing proppants (sand or alumina) need not be introduced to keep the fracture open.

The application of acoustic and/or hydraulic fracturing techniques through perforations allows fracturing to occur only in certain predefined directions; for example, into the area.

Prior to the shield, a reaming tool may be passed through the hole to break the sacrificial lining, allowing the material for excavation to collapse/collapse, thereby facilitating deployment of the removal process. The reaming tool may be connected to the pilot probe or may be delivered downwardly prior to use of the shield.

The processing may include stabilizing the underlying geology outside of the substantially prismatic region.

In this way, the material can be stabilized in the case of weak, void, unstable or water-soaked material outside the region. The device may be placed downhole to stabilize the underlying geology.

Stabilization may be achieved, for example, by coolant passing through the ground freezing technique, the coolant being pumped through the lining and possibly exiting the lining through perforations. Freezing and other stabilization techniques may be temporary.

Permanent stabilization may be achieved by injection of chemical stabilizers, for example, through chemical delivery nozzles (e.g., within telescoping arms). The amount and type of stabilizer used will depend on the geological conditions to be stabilized and can be controlled as desired and may include cements or any other suitable materials such as micro cements, mineral grouting (known as colloidal silica), water sensitive polyurethanes (quick reaction foaming resins to prevent water ingress), quick reaction and non-water sensitive polyurea silicate systems (expanding foam for void filling), acrylics, jet grouting, i.e. building a cured floor in situ according to design characteristics; commonly referred to as Soilcrete (RTM), etc.

Stabilization of the underlying geologic structure outside of the substantially prismatic region may also greatly reduce, if not prevent it entirely, further water ingress. Any groundwater remaining in the area of the tunnel to be excavated may be drained through the lowermost hole.

Stabilization or weakening as described above may be performed in synchronization with the shield so that the ground preparation does not need to be completed completely before the shield advance is started.

In particular, stabilization (e.g., using a jet grouting tool) may be directional; that is, stabilization may occur substantially outside of the prismatic regions, while cracking may occur substantially inside the prismatic regions. The underlying geological stability outside the substantially prismatic region may be used to form the initial external structure (shell) of the tunnel prior to excavation.

The excavation of the tunnel may include only the step of excavating material within the prismatic region, or may include other steps, such as drilling and/or lining the tunnel.

According to a second aspect of the present invention, there is provided a tunnel construction method comprising the steps of: providing a tunnel shield as described in the first aspect; moving a protective structure within a tunnel to be excavated to protect an interior region thereof from collapse; casting at least one guiding probe from the front edge of the movable protection structure into the geology of the tunnel to be excavated; grouting into geology by using a jet grouting tool, so that the quality of the grouting tool is improved.

The above and other features, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Fig. 1 is a cross-sectional view of a tunnel defined by circular holes.

Fig. 2 is a side view of a hole drilled into a hillside.

Fig. 3 is a complete tunnel cross-section, similar to fig. 1.

Fig. 4 is a side view of a dragline shield.

Fig. 5 is a view of a downhole wireline return cradle.

The invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each of the figures may not include all of the features of the present invention and therefore should not be considered an embodiment of the present invention. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and relative dimensions do not correspond to actual reductions in practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the operations are capable of operation in other sequences than described or illustrated herein. Likewise, method steps described or claimed in a particular order may be understood as operating in a different order.

Furthermore, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the operation is capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term 'comprising', used in the claims, should not be interpreted as being limitative to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components or groups thereof. Thus, the scope of the expression "a device comprising means a and B" should not be limited to a device consisting of only components a and B. This means that for the purposes of the present invention, the only relevant components of the device are a and B.

Similarly, it should be noted that the term "coupled" as used in the description should not be interpreted as limited to direct coupling only. Thus, the scope of the expression "device a connected to device B" should not be limited to devices or systems in which the output of device a is directly connected to the input of device B. This means that the path between the output of a and the input of B may be a path comprising other devices or means. "connected" may mean that two or more elements are in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. Consider, for example, a wireless connection.

Reference throughout this specification to "one embodiment" or "an aspect" means that a particular feature, structure, or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, the appearances of the phrase "in one embodiment" or "in one aspect" in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may. Furthermore, it will be apparent to one of ordinary skill in the art that any particular feature, structure, or characteristic of any embodiment or aspect of the invention may be combined with any other particular feature, structure, or characteristic of another embodiment or aspect of the invention in any suitable manner.

Similarly, it should be appreciated that in the description, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Furthermore, any individual figures or descriptions of aspects should not be considered as examples of the present invention. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features contained in other embodiments, combinations of features of different embodiments are intended to be within the scope of the invention and form additional embodiments, as will be appreciated by those of skill in the art. For example, in the following claims, any of the claimed embodiments may be used in any combination.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the present invention, unless indicated to the contrary, the disclosure of alternative values for the upper or lower limit of the permissible range of a parameter, plus an indication that one of the values is more preferred than the other, should be interpreted as implying that each intermediate value of the parameter lying between the more preferred and less preferred of the alternatives is itself preferred over the less preferred value and over each value between the less preferred value and the intermediate value.

In some cases, the use of the term "at least one" may mean only one. In some cases, the use of the term "any" may mean "all" and/or "each.

The principles of the present invention will now be described in detail with reference to at least one drawing associated with exemplary features. It is obvious that other arrangements may be configured according to the knowledge of a person skilled in the art without departing from the basic concept or the technical teaching, the invention being limited only by the terms of the appended claims.

Fig. 1 is a cross-sectional view of a tunnel defined by circular holes. Three central guide holes 10 are drilled along the path of the tunnel. A plurality of shape defining holes 20 are drilled around these holes 10 to form an arch-shaped tunnel profile with a flat lower layer. The inclination angle of the tunnel is optimized according to the specific requirements of the relevant tunnel and may be, for example, vertical.

Fig. 2 is a side view of the pilot hole 10 and the shape defining hole 20 during drilling into the hill 30, each hole 10, 20 being shorter in length than their final length. It will be appreciated that some of the holes may be drilled simultaneously with other holes, some of the holes may be completed before other holes begin, and/or some of the holes may be partially drilled and interrupted while other holes continue the drilling operation.

Fig. 3 is a view of a cross section of a finished tunnel 100 similar to fig. 1 in the hillside 30 of fig. 2. Outside the section 80 defined and excavated by the shape defining bore 20, the underlying geology has been consolidated/stabilized to form a reinforced region 90 surrounding the tunnel. An example of a lining option that may be applied is described as the outer concrete lining 120 being separated from the inner concrete lining 110 by a waterproofing membrane 115 when required.

There are many other tunnel lining and finishing methods. For example, a temporary reusable metal former may be placed in the tunnel and concrete 120 applied to the back of the former to form a smooth tunnel inner wall. Once the concrete 120 has hardened completely, the temporary former may be removed and reused in another portion of the tunnel, leaving the smooth concrete 120 as the inner wall.

Alternatively, during excavation, two shape-defining apertures 20 on the tunnel bottom may be left to serve as channels/grooves 130 to help guide the machine (particularly the dragline shield) along the tunnel. Once tunneling is complete, these trenches/trenches 130 may be filled at a later time.

Fig. 4 is a side view of a dragline shield. Arrow 200 represents the direction of movement of the dragline shield during excavation. The profile of the dragline shield matches the predefined external tunnel shape. The angle of inclination of shield leading edge 202 is optimized for the specific requirements of the tunnel concerned and may be, for example, vertical.

The shield may be advanced into the tunnel by pushing hydraulic ram 206 of the dragline shield and/or by cable 208 attached to the end of the guide probe, which passes through the (lined/unlined) hole to the winch that pulls the dragline shield forward. The latter would be the preferred method as it facilitates continuous movement.

The lower shape defining aperture along the tunnel bottom may be cleaned up behind the point where the waste soil enters the shield so that the wheels 210 (or optional landing gear) of the dragline shield may travel from the sacrificial lining in the left-behind thick half pipe, which remains in place. With the pushing of the dragline shield, the track does not need to be installed or prolonged.

The guide probe 204 on the guide surface of the shield is aligned with and extends into the shape defining aperture. The guide probes 204 are spaced and sized such that they engage the shape defining apertures and the dragline shield is moved forward through the now predefined tunnel shape. Although the accuracy of the holes is very accurate, if the path of the holes deviates from the target route, the guiding probe 204 will be able to tolerate some variation. Short stretches, where out-of-tolerance deviations have occurred, can see the pilot probe retracted until it can be re-engaged after digging for a period of time by other means, such as boom-mounted cutting head 212 found on a heading machine unit.

The guide probes 204 are provided with interchangeable tools so that they can be either coarse or fine tuned as appropriate. These interchangeable tools include, but are not limited to, disk cutters, rotary cutting cylinders or cone cutters, toothed chainsaw arms for the material being processed, high pressure water, coulters 214, and hydraulic splitters 216 that can apply tremendous pressure directly as needed, which can apply tremendous pressure around the circumference/perimeter of the tunnel profile and/or inwardly (toward the interior of the tunnel) as needed to further loosen and break up the material to be removed (in addition to removing the sacrificial lining shaped to define the hole).

Collapse/collapse techniques may be used with soft and/or loose materials to be excavated, particularly if areas outside the tunnel perimeter have been stabilized to form a self-supporting enclosure. For this type of operation, the guide probe is fitted with a coulter 214 as the dragline shield is advanced.

A laser array (not shown) will continuously scan 218 the freshly exposed excavated outer surface to ensure that no material is left to protrude inwardly so as not to contaminate or impede the progress of the dragline shield. Ground penetrating radar can also be used where waste soil covers the just exposed tunnel area. If any such area is found, it will be immediately processed by one or more robotic arms 212 without impeding progress, wherein one or more robotic arms 212 are fitted with a pneumatic drill or interchangeable cutting head or other suitable tool.

Working under the protection of the dragline shield, the waste soil is continuously excavated (with the assistance of the mechanical digger 220, if necessary) onto the loading mechanism 222 within the shield. The spoil may be loaded onto the loading mechanism 222 primarily by the dragline shield moving forward through the spoil, much like a bulldozer action. Removing the excavated waste soil by a conventional method; the waste soil has moved back on the conveyor 224 to a position where the newly laid tunnel bottom is able to carry heavy machinery.

Fig. 5 is a view of the downhole cable return cradle, wherein the cradle housing 250 is shown transparent. A clamping system 252 is provided on the housing 250, the clamping system 252 engaging a wall of the hole with lining, the clamping system being deployed within the hole. The clamping system 252 may be engaged or disengaged by an operator to allow the carriage to move within the aperture and be secured in place in preparation for winch operation. A first end of the cable 254 is connected to the shield. A second end of the cable 256 is connected to the winch. When the winch is wound on the second end of the cable 256, a series of pulleys 258 within the carriage reverse the cable such that the shield is pulled by the first end of the cable 254.

Claims (5)

1. A tunnel shield, comprising:

a mobile protective structure for use during tunnel excavation, the mobile protective structure being configured to protect an interior region thereof from tunnel collapse;

at least one steering probe arranged to extend from the leading edge of the mobile protection structure into the geology of the tunnel to be excavated; and

a jet grouting tool is positioned on the at least one guiding probe, the jet grouting tool being configured to pour slurry into the earth to enhance its quality.

2. The tunnel shield of claim 1 configured to deposit reinforcing members into material that has been poured during jet grouting.

3. The tunnel shield of claim 1 or claim 2 wherein the at least one steering probe comprises a plurality of steering probes, each steering probe having a jet grouting tool disposed thereon, wherein the jet grouting tools are configured to be activated simultaneously.

4. The tunnel shield of claim 1 or claim 2 wherein the at least one steering probe comprises a plurality of steering probes, each steering probe having a jet grouting tool disposed thereon, wherein the jet grouting tools are configured to be independently activated.

5. A tunnel construction method comprises the following steps:

providing a tunnel shield as claimed in any one of the preceding claims;

moving the protective structure within the tunnel to be excavated to protect its interior region from collapse;

projecting the at least one steering probe from the leading edge of the movable protective structure into the geology of the tunnel to be excavated; and

grouting is performed into the geology by using the jet grouting tool to improve the quality thereof.

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