Patent Description:
A tunnel boring machine (TBM) is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock. Tunnel diameters can range from <NUM> meter (done with micro-TBMs) up to around <NUM> meters. Tunnels of less than <NUM> meter or so in diameter are typically done using horizontal directional drilling rather than TBMs.

Tunnel boring machines are used as an alternative to drilling and blasting methods in rock, and conventional "hand mining" in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel and makes them suitable to use in heavily urbanized areas. The major disadvantage is cost, since TBMs are expensive to construct and can be difficult to transport. The longer the tunnel, the less the relative cost of tunnel boring machines versus drill and blast methods. This is because tunneling with TBMs is more efficient and results in shortened completion times (and is thus relatively safer).

Modern TBMs typically consist of the rotating cutting wheel, called a cutter head, followed by a main bearing, a thrust system and a trailing support arrangement. The type of machine used depends on the particular geology of the project, the amount of ground water present and other factors. In hard rock, which is typically where TBMs are most commonly used, either shielded or open-type TBMs can be used. In addition, TBMs can be used in either a 'wet-cutting' application, in which mist is sprayed onto the cutter head, or in a 'dry-cutting' application, in which no mist is spayed. In all cases, however, TBMs excavate hard rock using disc cutters mounted on the cutter head. The disc cutters create compressive stress fractures in the rock, causing it to chip away from the rock in front of the machine, called the tunnel face. The excavated rock, known as muck, is transferred through openings in the cutter head to a belt conveyor, where it runs through the machine to a system of conveyors or muck cars for removal from the tunnel.

Open-type TBMs have no shield, and are thus unsupported, which is not ideal from a safety point of view. To advance, the machine uses a gripper system that pushes against the side walls of the tunnel. The machine will then push forward off the grippers gaining thrust. At the end of a stroke, the rear legs of the machine are lowered, the grippers and thrust cylinders are retracted. The retraction of the thrust cylinders repositions the gripper assembly for the next boring cycle. The grippers are extended, the rear legs lifted, and boring begins again. The open-type TBM typically uses ground support methods, such as ring beams, rock bolts, shotcrete, steel straps, ring steel and wire mesh.

It is thus an aim of the present invention to provide a mobile underground tunnel borer arrangement that addresses most of the inherent problems or disadvantages associated with conventional TBMs, whilst still retaining and utilising the proven advantages associated with current TBMs.

In terms of known prior art, <CIT> discloses an excavation machine comprising an outer body and an inner body that can be displaced therein by means of cylinder-piston units. On the front end of the inner body, a rotary working head is rotatably mounted, from which radially pivotable tool arms (fitted with tools at their ends) are mounted. The outer body is carried together with a base frame by a crawler chassis and is equipped with gripper devices for vertically bracing against the floor and the roof of the drift in which the machine operates. A roof shield is mounted on the top of the outer body, the shield being connected to the outer body by coupling bars and cylinder-piston units and can be placed against the roof of the drift to protect the machine from falling rock. The machine further includes muck removing devices for collecting and transporting away the muck. In use, using the tool on a tool arm, the rock face may be cut radially by pivoting the tool arm.

In another prior art document, <CIT> provides a tunnel boring machine with a front drill head comprising a rotating drill tool holder. The drill head is rotated by a drive block, with the drill head and the drive block being mounted by means of a bearing on an inner kelly, which extends to the rear of the machine. The machine includes at least one advancement device that extends between the bracing device and the drill head. A force generator is also provided, which extends between a tubbing support and the drill head. The kelly is arranged to introduce the advancement forces into the drill head, which can be moved in the direction of boring in relation to the bracing device and to which the advancement generator is hinged. This machine further provides a drill cuttings conveyor, to carry away the cuttings, which extends through the interior of the inner kelly.

A further prior art disclosure is an article entitled "<NPL>. This document discloses an assembly method comprising lowering a mini crane and boom lift into an underground passage. Various components for an entrance frame are then lowered, with these components then being assembled to define an entrance frame, adjacent a face to be cut. Various cradle components are then lowered, a first cradle component is used to accommodate subsequent pieces of equipment, a second cradle is used to assemble these pieces, and a third cradle component is located adjacent the assembled entrance frame. Various pieces of a cutter head are then lowered and assembled on the second cradle component, with the second cradle component then being moved so as to be in line with the third cradle component. The assembled cutter head is then slid onto the third cradle component, so as to be adjacent the assembled entrance frame, with a conveyor screw, a rear deck and related support work then being installed behind the assembled cutter head, ready for use.

According to the invention, there is provided a mobile tunnel boring unit according to claims <NUM> to <NUM> and a method of boring a tunnel according to claims <NUM> to <NUM>.

The front shield accommodates cutter head drive means (mounted onto the cutter head) to rotatingly drive the cutter head, the cutter head drive means typically comprising hydraulic drive motors that drive a ring gear which is stabilised by a thrust bearing. A special sealing arrangement is provided to keep dust outside so as to not penetrate the cutter head drive means. The cutter head drive means was shaped specifically to aid fast assembly of the front shield in the correct sequence. A special quick attachment method is used to aid fast assembly/connection between the cutter head drive means to the cutter head when the cutter head has been assembled in the cutting face. The cutter head drive was designed with an open hollow centre to allow the main conveyor to collect dust inside the cutter head. The same opening allows access to the cutter head for maintenance.

In an embodiment, an actuating arrangement, comprising a plurality of hydraulic thrust cylinders, extends between the cutter head drive means and a support arrangement on a rear end of the mobile tunnel boring unit, the actuating arrangement being arranged to telescopingly move the front shield relative to the support arrangement on a rear end of the mobile tunnel boring unit, and thus relative to the rear shield which is fixed to the rear end of the mobile tunnel boring unit.

The thrust cylinder arrangement provides a flexible link between the cutter head drive and the support arrangement, that allows for correction of the support arrangement after rotational slippage. The thrust cylinders, typically four pairs of thrust cylinders, extend slightly inwardly from the support arrangement on the rear end of the mobile tunnel boring unit towards the cutter head drive means. This enables the mobile tunnel boring unit arrangement to be steered in all directions i.e. up, down, left and right, thus enabling cut-aways, cross-cuts, declines, inclines and even spiral shafts to be bored. Connection of the thrust cylinders are via spherical ball joints on either end to accommodate free movement. The thrust cylinders are equipped with position sensors, enabling the system to establish the position of the cutter head relative to the support arrangement.

In an embodiment, the gripper arrangement includes a front gripper stabilizer assembly, fitted to, so as to extend from, the front shield, and a rear gripper assembly, fitted to, so as to extend from, the support arrangement on a rear end of the mobile tunnel boring unit. Each gripper assembly includes a support body and two movable, curved gripper elements that can be extended and retracted, using first actuators, relative to their respective support body. A stabilizer gripper assembly extends at <NUM>° and the rear gripper assembly extends at <NUM>°. In the extended position, the curved gripper elements grip against the tunnel wall, and in the retracted position, the mobile tunnel boring unit can be pulled forwards. In an embodiment, the gripper elements take the form of curved gripper pads that are fitted on pin type spherical joints to accommodate free movement.

In an embodiment, the cutter head takes the form of a full face cutter head fitted with disc cutters, the cutter head defining scoops and channels to allow cuttings and muck to pass automatically through the cutter head for discharge into a muck hopper and collection onto a first conveyor arrangement located immediately behind the cutter head. The first conveyor arrangement extends through the mobile tunnel boring unit for subsequent offloading onto a first backup unit.

In an embodiment, the cutter head is detachably secured to the mobile tunnel boring unit using a quick attachment method, which improves the efficiency of the boring cycle. The centre segment has a tapered profile to accommodate accurate segment attachment. All cutters are of the back-loading type, to accommodate efficient maintenance. In addition, the cutter head comprises a plurality of segments that can be pre-installed with the front shield. The cutter head may also have varying sizes, as required in use; the envisaged diameter range is between <NUM> metres and <NUM> metres. This is achieved by having a common centre segment onto which the various segments for the <NUM> and <NUM> configurations are bolted.

The first conveyor arrangement extends through the mobile tunnel boring unit for subsequent offloading onto a first backup unit. The first conveyor is retractable away from the cutter head drive to allow access for cutter change and maintenance. All conveyors are designed with variable geometry, to enable the conveyors to be compacted to assist manoeuvrability during transportation. All conveyors have a modular design to enable common parts inventory to ease spares and maintenance requirements. In an embodiment, the first, second and third conveyor arrangements are all collapsible, so as to improve and facilitate manoeuvrability.

In an embodiment, a support drill rotation ring and associated ring drive means to rotate the ring are fitted proximate the rear end of the mobile tunnel boring unit, typically behind the support arrangement. The support drill rotation ring carries two spaced apart drills, to facilitate the fitting of rock bolt supports to the surrounding wall. The drills are able to rotate on their own axes to allow a V-configuration for varying support bolt drilling arrangements. The drills are equipped with sliders so they can be stabilised against the tunnel wall. The shields house the probe drill near the cutter head. The probe drill position and orientation can be manually adjusted to allow cover drilling in three directions through the cutter head. In turn, the cutter head is equipped with three openings through which the probe drill rods can advance.

In an embodiment, the rear shield includes a plurality of fingers that define gaps through which the drills can extend and drill. These fingers are hydraulically actuated to provide adjustment during transport and also support to the tunnel wall during support drilling, to protect the support drill operators. Shields are designed to be modular, to ease transport by limiting size and weight. Shield assembly is efficient with a shield interface, resulting in quick alignment and easy access for fasteners. The bottom/belly shield segment stabilises the mobile tunnel borer, in cooperation with the gripper pads, by skidding on the tunnel invert at all times. The belly shield is equipped with replaceable wear plates to extend its operating lifespan. Shields operate telescopically relative to each other, assisting in machine mobility and agility whilst boring direction changes and curves.

In an embodiment, the first drive means for driving the mobile tunnel boring unit includes a pair of spaced apart tracks in contact with the tunnel floor, and related track driving means to move the tracks, and thus the mobile tunnel boring unit. In an embodiment, the tracks are mounted to the bottom of the mobile tunnel boring unit and can hydraulically be pivoted/adjusted, to better accommodate the round shape of the bored tunnel. In addition, the tracks can be moved with six degrees of freedom relative to the boring unit, to accommodate varying diameters of the boring unit and perfect alignment when assembling the mobile tunnel borer to the cutter head. The crawler tracks are also equipped with stabilising cylinders that are actuated to lift the mobile tunnel borer from its tracks when a pivot adjustment is made. The crawler tracks are powered by a diesel powered hydraulic motivator, which is latched to the back of the mobile tunnel boring unit. The crawler track is operated by a handheld remote control, by one operator in close proximity to the mobile tunnel borer.

In an embodiment, the first backup unit is fitted with a second conveyor arrangement to receive the cuttings and muck from the first conveyor arrangement on the mobile tunnel boring unit towards a second backup unit. In an embodiment, the first backup unit is fitted with the main hydraulic power pack and also the electric panel that is equipped with the PLC system. The first back-up unit is also fitted with the scrubber unit to assist with dust suppression.

In an embodiment, the third backup unit is fitted with a third conveyor arrangement to receive the cuttings and muck from the second conveyor arrangement on the first backup unit towards a truck. In an embodiment, the second backup unit is fitted with the cooling water circulation pumping system. The second back-up unit is also fitted with the main incoming transformer substation and also the dust extraction fan unit. Cable and hose reels are fitted as well to allow continuous operation for <NUM> meters.

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings. In the drawings:.

The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiment described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not a limitation thereof.

Referring to <FIG> of the drawings, a mobile underground tunnel borer arrangement <NUM>, according to a first embodiment or version of the invention, comprises a front or leading mobile tunnel boring unit <NUM> and at least one rear, trailing backup or auxiliary unit <NUM>. The mobile tunnel boring unit <NUM> includes first drive means <NUM> to drive the mobile tunnel boring unit <NUM>, a gripper arrangement <NUM> to facilitate boring (by providing the required gripping and thrusting), and a rotatable cutter head <NUM> fitted with cutters <NUM> to bore the tunnel face. The gripper arrangement <NUM> includes a front gripper assembly <NUM> and a rear gripper assembly <NUM>. Each gripper assembly <NUM>, <NUM> includes a support body <NUM>, <NUM> and four movable gripper elements <NUM>, <NUM> that can be extended and retracted, using first actuators (typically, hydraulic pistons), relative to the support body <NUM>, <NUM>. In the extended position, the gripper elements <NUM>, <NUM> grip against the tunnel wall and in the retracted position, the first drive means <NUM> can be operated to move the mobile tunnel boring unit <NUM>.

The gripper elements <NUM>, <NUM> typically include gripper pads that are fitted on spherical joints. The spherical joints enable steering, both left and right steering and up and down steering. In use, the front gripper assembly <NUM> moves forwards with the cutter head <NUM>, and the rear gripper assembly <NUM> extends out to engage against the tunnel. In particular, the front gripper assembly <NUM> stabilises the cutter head <NUM> while the rear gripper assembly <NUM> provides thrust. After advancing <NUM> metre, for example, the front gripper assembly <NUM> clamps against the tunnel and the rear gripper assembly <NUM> retracts. In one version, because there is no overall support for the mobile tunnel boring unit <NUM>, the top two gripper elements <NUM>, <NUM> can retract, to enable the mobile tunnel boring unit <NUM> to be dragged through the tunnel.

In an embodiment, the four movable gripper elements <NUM>, <NUM> extend at <NUM> degree angles around the support body <NUM>, <NUM>, so as to define an X. The front and rear gripper assemblies <NUM>, <NUM> are fitted to either end of a torque shaft housing <NUM> for accommodating a torque shaft that connects a gearbox <NUM> with the cutter head <NUM>. Second actuators <NUM> (typically hydraulic pistons) are arranged to extend and retract the support body <NUM>, <NUM> of the front gripper assembly <NUM> and the cutter head <NUM> relative to the torque shaft housing <NUM>. In an embodiment, the cutter head <NUM> includes a central engaging face <NUM> with a plurality of (typically four) modular cutter segments <NUM> extending at an angle away from the central engaging face <NUM>. This arrangement defines a tapered, self-centring arrangement. In one version, the cutter segments <NUM> can be removed from the cutter head <NUM> (similar to a raise borer head); in another version, the cutter segments <NUM> can be movably collapsible relative to the cutter head <NUM>.

A dust shield <NUM> is provided between the front gripper assembly <NUM> and the cutter head <NUM>. A conveyor arrangement <NUM> extends from the dust shield <NUM> to enable the muck and cuttings to be transported to a tunnelling truck <NUM> for subsequent disposal. The conveyor arrangement <NUM> comprises a first conveyer <NUM> on top of the mobile tunnel boring unit <NUM>, to receive the cuttings via a chute <NUM> provided on the dust shield <NUM>, and a second conveyor <NUM> on top of the backup unit <NUM> to continue conveying the cuttings towards the truck <NUM>. In use, the rotating cutter head <NUM> lifts the cuttings as it rotates, and then dumps the cuttings into the chute <NUM>, and then onto the first conveyor <NUM>. In use, two trucks <NUM> may be used per borer arrangement <NUM>, in a shuttling manner to haul muck away. One additional truck may be provided for every <NUM> tunnel length.

The borer arrangement <NUM> includes a ventilation duct <NUM> that runs from the dust shield <NUM> all the way to a scrubber unit <NUM> at the back of the borer arrangement <NUM>. The borer arrangement <NUM> further includes a fresh air pipe <NUM> to blow fresh air into the working area of the borer arrangement <NUM>. In an embodiment, the borer arrangement <NUM> includes a support drill <NUM> and related platform <NUM>, which is disconnected from the mobile tunnel boring unit <NUM>. In use, as the borer arrangement <NUM> is drilling and vibrating, the support drill <NUM> and platform <NUM> will be stable, thereby allowing personnel to work on top of the platform <NUM>. In particular, a person can stand on top of the platform <NUM> can perform the necessary drilling for the support work. This drilling would typically be done from -<NUM> degrees from horizontal all the way around to -<NUM> degrees on the other side.

The backup unit <NUM> includes second drive means <NUM> to drive the backup unit <NUM>, and a support frame <NUM> on top of the second drive means <NUM>. An advantage of having two separate units <NUM>, <NUM> is to improve mobility and to allow all the required equipment, such as hydraulic power packs, gearboxes, motors, water and cable reels etc, to be arranged so as to provide a balanced arrangement. The borer arrangement <NUM> includes walkways <NUM> on both sides of the machine <NUM>. In an alternate embodiment, instead of the cutter head and cutters cutting forwardly, as described above, they may be arranged to cut from the inside out. As a result, there is nothing pushing the borer arrangement back, thus simplifying the need for the gripper arrangements. This arrangement would also allow hydraulics and other equipment, and conveyors, to be brought through the centre of the head, and would allow hydraulic activation on the head in the front as well.

Turning now to <FIG> of the drawings, a mobile underground tunnel borer arrangement <NUM>, according to a second embodiment or version of the invention is shown. The borer arrangement <NUM> comprises a mobile tunnel boring unit <NUM> and at least one rear, trailing backup unit <NUM>, as described in more detail further below. The mobile tunnel boring unit <NUM> includes a support body <NUM> (best shown in <FIG>) driven by first drive means <NUM>. The first drive means <NUM> for driving the mobile tunnel boring unit <NUM> includes a pair of spaced apart crawler tracks <NUM> in contact with the tunnel floor <NUM>, and related track driving means <NUM> to move the tracks <NUM>, and thus the support body <NUM> of the mobile tunnel boring unit <NUM>. The tracks <NUM> are relatively wide to better support the mobile tunnel boring unit <NUM>. In addition, as best shown in <FIG>, the tracks <NUM> are mounted to a cross support <NUM> with pivot pins <NUM>, to better accommodate the round shape of the bored tunnel. In addition, a hydraulic cylinder <NUM> is fitted between the cross support <NUM> and the support body <NUM> (not shown), to lift the upper part of the boring unit <NUM> relative to the tracks <NUM> (which will be explained in more detail further below). This is one configuration of a lifting configuration to lift the support body <NUM> relative to the tracks <NUM> (the other configuration is described further below). This lifting arrangement conveniently accommodates the round bored tunnel and is particularly useful to accommodate varying diameters of the boring unit <NUM>, as will be explained in more detail further below with reference to <FIG>, and to ensure alignment when assembling the mobile tunnel boring unit <NUM> to a cutter head <NUM> (explained in more detail further below). As best shown in <FIG>, another lifting arrangement is shown, comprising two pairs of criss-cross lifting cylinders <NUM>. The cylinders <NUM> may be actuated to lift the support body <NUM> (and thus the upper portion of the mobile tunnel boring unit <NUM>) relative to the tracks <NUM>. The crawler tracks <NUM> are powered by a diesel powered hydraulic motivator, which is latched to the back of the mobile tunnel boring unit <NUM>. The crawler tracks <NUM> are operated by a handheld remote control, by one operator in close proximity to the boring unit <NUM>.

As best shown in <FIG> and <FIG>, the mobile tunnel boring unit <NUM> further comprises a round rotatable cutter head <NUM> fitted with cutters <NUM> to bore the tunnel face <NUM> shown in <FIG>. The round bored tunnel is particularly advantageous in underground situations, primarily due to its inherent strength. In the illustrated version, the cutter head <NUM> includes a full face cutter head <NUM> with disc cutters <NUM>, the cutter head <NUM> defining scoops <NUM> (best shown in <FIG>) and channels <NUM> (best shown in <FIG>) to allow cuttings and muck to pass automatically through the cutter head <NUM> for discharge into a muck hopper <NUM> (best shown in <FIG>) and collection onto a first conveyor arrangement <NUM> located immediately behind the cutter head <NUM> (as best shown in <FIG>). With particular reference to <FIG> and <FIG>, the cutter head <NUM> comprises four peripheral modular cutter segments <NUM> and a central cutter head segment <NUM>. The size of the peripheral cutter segments <NUM> are variable, depending on the size of the tunnel to be bored, while the central cutter head segment <NUM> remains the same irrespective of the tunnel size, so as to define a common centre. The central cutter head segment <NUM> defines a central aperture <NUM> to enable the back loading of the cutters <NUM>, as best shown in the cross-sectional perspective view indicated by arrow <NUM>. As best shown in <FIG>, the central cutter head segment <NUM> has tapered side walls <NUM>, with the corresponding inner faces of the peripheral cutter segments <NUM> being tapered accordingly. This ensures a tight fit between the segments <NUM> and <NUM>, with the central cutter head segment <NUM> in turn being connected to the main drive <NUM> (discussed further below) using a quick connection arrangement. In use, and as shown in <FIG>, the muck hopper <NUM> extends through the central aperture <NUM> of the central cutter head segment <NUM> to receive the cuttings for transport by the first conveyor arrangement <NUM>.

As best shown in <FIG>, <FIG> and <FIG>, the first conveyor arrangement <NUM> extends through the mobile tunnel boring unit <NUM> for subsequent offloading onto a first backup unit <NUM>, which is described in more detail further below. The first conveyor arrangement <NUM> comprises a front conveyor section <NUM> and a rear conveyor section <NUM>, with the front conveyor section <NUM> being retractable away from the cutter head drive means <NUM>, out from under the muck hopper <NUM>, to allow access for cutter change and maintenance. The rear conveyor section <NUM> is typically enclosed under a cover <NUM>, which is primarily used as a safety measure and to reduce dust within the mobile tunnel boring unit <NUM>.

The mobile tunnel boring unit <NUM> is fitted with a telescopic shield arrangement <NUM>, as best shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>. The shield arrangement <NUM> comprises a front shield <NUM> proximate the front of the mobile tunnel boring unit <NUM>, from which the cutter head <NUM> protrudes, and a rear shield <NUM> that surrounds at least an upper portion of the mobile tunnel boring unit <NUM>. The front and rear shields <NUM>, <NUM> operate telescopically relative to each other, to assist the mobility and agility of the boring unit <NUM> as the boring direction changes and curves. The front shield <NUM> in turn comprises a plurality of peripheral modular segments <NUM> to <NUM> joined together, which further assists with the compact and manoeuvrable design of the mobile tunnel boring unit <NUM>. The shield arrangement <NUM> thus provides a fully supported zone proximate the tunnel face <NUM> being bored. The peripheral segments <NUM> to <NUM> define an aperture <NUM> in the middle, to accommodate the front conveyor section <NUM> therethrough. One of the segments <NUM> to <NUM> is a bottom/belly shield segment <NUM>, which stabilises the mobile tunnel boring unit <NUM>, in cooperation with gripper pads <NUM> (explained in more detail further below), by skidding on the tunnel invert at all times. The belly shield segment <NUM> is equipped with replaceable wear plates to extend its operating lifespan. The shield arrangement <NUM> is modular to ease transport, by limiting size and weight. The shield arrangement <NUM> is designed to be assembled quickly and efficiently, with reference to <FIG> as well, with the shield interface providing quick alignment and easy access for fasteners.

The front shield <NUM> (together with the cutter head <NUM>, as described above) can be detached from the rest of the mobile tunnel boring unit <NUM>, and is typically pre-installed in a starting chamber, as will be described in more detail further below with reference to <FIG>, and in <FIG>. The front shield <NUM> accommodates cutter head drive means <NUM>, best shown in <FIG>, <FIG>, 10B and <FIG>, to rotatingly drive the cutter head <NUM>. The cutter head drive means <NUM> is mounted onto the cutter head <NUM>, and typically comprises hydraulic drive motors that drive a ring gear which is stabilised by a thrust bearing. A sealing arrangement is used to prevent against the ingress of dust, thereby preventing against dust from penetrating the cutter head drive means <NUM>. The drive means <NUM> defines an aperture <NUM> in the middle, as best shown in <FIG>, to accommodate the front conveyor section <NUM> therethrough. The aperture <NUM>, in conjunction with the central aperture <NUM> of the central cutter head segment <NUM>, facilitates access to the cutters <NUM>, for ongoing maintenance.

As will be described in more detail below with reference to <FIG>, <FIG> and <FIG> in particular, the cutter head drive means <NUM> is shaped specifically to aid fast assembly of the front shield <NUM> in the correct sequence. In addition, a quick attachment method was developed to aid fast assembly/connection between the cutter head drive means <NUM> to the cutter head <NUM> when the cutter head <NUM> has been assembled in the cutting face. As indicated above, and with particular reference to <FIG> and <FIG>, the cutter head <NUM> may also have varying sizes, as required in use. In particular, these figures show two possible diameter sizes of the mobile tunnel boring unit <NUM> of the mobile underground tunnel borer arrangement <NUM>, namely a <NUM> metre diameter machine (shown in <FIG> and indicated by arrow <NUM> in <FIG>), and a <NUM> metre diameter machine (shown in <FIG> and indicated by arrow <NUM> in <FIG>). Significantly, an identical mobile tunnel boring unit <NUM> can be used for both sizes, with only the shield arrangement <NUM> (and in particular the front shield <NUM>) and the cutter head <NUM> needing to be changed. In addition, the central cutter head segment <NUM> described above allows the four peripheral cutter segments <NUM> for the <NUM> and <NUM> configurations to be secured in place (described further below with reference to <FIG>, <FIG> and <FIG>). For the <NUM> metre diameter machine <NUM>, an additional bunker car <NUM> is typically used to provide additional storage capacity, as shown in <FIG>.

<FIG> and <FIG> show the relative positioning of the support body <NUM> (and thus the upper part of the mobile tunnel boring unit <NUM>), relative to the tracks <NUM>, depending upon the machine size. Thus, for example, in the <NUM> metre configuration (i.e. <FIG>, and arrow <NUM> in <FIG>), the cylinder <NUM> (in one configuration) or the cylinders <NUM> (in the other configuration) are retracted, in order to lower mobile tunnel boring unit <NUM> (and in particular the support body <NUM>). Conversely, in the <NUM> metre configuration (i.e. <FIG>, and arrow <NUM> in <FIG>), the support body <NUM> and mobile tunnel boring unit <NUM> are raised, with the cylinders <NUM>, <NUM> accordingly being extended.

Turning now to <FIG>, an actuating arrangement <NUM>, comprising a plurality of hydraulic thrust cylinders <NUM>, extends between the cutter head drive means <NUM> and a pair of opposite gripper assemblies <NUM>. The connection of the thrust cylinders <NUM>, on both ends, takes the form of spherical ball joints <NUM>, to allow free movement. The front shield <NUM> is secured to the outside of the main drive <NUM>, whereas the rear shield <NUM> is secured to the rear end of the mobile tunnel boring unit <NUM>, as shown in <FIG>. In this way, the actuating arrangement <NUM> is arranged to telescopingly move the front shield <NUM> relative to the mobile tunnel boring unit <NUM> (and thus the rear shield <NUM>). This telescoping movement further assists with the compact and manoeuvrable design of the mobile tunnel boring unit <NUM>.

The thrust cylinders <NUM>, typically four pairs of thrust cylinders, two pairs on either side of the unit <NUM>, extend slightly inwardly from the gripper assemblies <NUM> towards the cutter head drive means <NUM>, as best shown in <FIG>. This enables the mobile tunnel boring unit <NUM> to be steered in all directions (i.e. up, down, left and right, and thus even enabling spiral shafts to be bored), as best shown in <FIG>. In this figure, two paths <NUM>, <NUM> are shown; in the first path <NUM>, the cutter head <NUM> extends at an angle of <NUM> degrees relative to the rest of the borer arrangement <NUM>, whereas in the second path <NUM>, the cutter head <NUM> extends at an angle of <NUM> degrees relative to the rest of the borer arrangement <NUM>. The mobile tunnel boring unit <NUM> has a turning radius of approximately <NUM> metres.

The arrangement of the thrust cylinders <NUM> acts as a flexible link between the cutter head drive means <NUM> and the rest of the mobile tunnel boring unit <NUM>, which allows for correction of the mobile tunnel boring unit <NUM> after rotational slippage. The thrust cylinders <NUM> are equipped with position sensors <NUM>, enabling the mobile tunnel boring unit <NUM> to establish the position of the cutter head <NUM> relative to the rest of the mobile tunnel boring unit <NUM> (and in particular the gripper assemblies <NUM>).

The mobile tunnel boring unit <NUM> includes a gripper arrangement to facilitate boring (by providing the required gripping and thrusting). The gripper arrangement includes a pair of front, relatively smaller, gripper assemblies <NUM> (best shown in <FIG>), arranged to protrude from the front shield <NUM>, and a pair of rear, relatively larger gripper assemblies <NUM>, fitted to, so as to extend from, the support body <NUM>. In particular, the smaller, gripper assemblies <NUM> define a V (and thus extend radially upwardly at <NUM> degrees), on either side of an upper edge of the front shield <NUM>. The larger gripper assemblies <NUM> extend on opposite sides of the mobile tunnel boring unit <NUM>, with cylinder barrels <NUM> (best shown in <FIG>) being carried on the support body <NUM>, for guiding the movement of the gripper assemblies <NUM>. The gripper assemblies <NUM> include movable, curved gripper elements <NUM>. Under the control of the thrust cylinders <NUM>, the gripper assemblies <NUM> can be extended and retracted, relative to the mobile tunnel boring unit <NUM>. In the extended position, the gripper elements <NUM> grip against the tunnel wall, and in the retracted position, the mobile tunnel boring unit <NUM> is free to move forwards. In particular, in use, the mobile tunnel boring unit <NUM> remains in contact with the floor. After the rear gripper assembly <NUM> retracts, the smaller gripper assembly <NUM> extends, with the actuating arrangement <NUM> then being used to pull the rear of the mobile tunnel boring unit <NUM> forwards. Thus, rear gripper assembly <NUM> provides thrust, while the smaller gripper assembly <NUM> provides stabilisation. In an embodiment, the curved gripper elements <NUM> take the form of curved gripper pads that are fitted on pin type spherical joints to accommodate free movement and minimise pressure on the rock formation.

As best shown in <FIG>, the mobile tunnel boring unit <NUM> further includes a support drill rotation ring <NUM>, and associated ring drive means <NUM> to rotate the ring <NUM> through <NUM> degrees, fitted proximate the rear end of the mobile tunnel boring unit <NUM>. The support drill rotation ring <NUM> carries two spaced apart drills <NUM>, to facilitate the fitting of rock bolt supports to the surrounding wall, and which can operate simultaneously to increase productivity i.e. the support bolts are drilled and installed simultaneously. As best shown in <FIG>, the drills <NUM> are typically fitted to the rotation ring <NUM> to define a V-configuration. Roof bolts of up to <NUM> metres in length and/or support mesh can be fitted using this arrangement, as indicated by lines <NUM> in the fully drilling pattern. Thus, is use, the ring <NUM> rotates through <NUM> degrees, stopping at four distinct positions or intervals, as shown, to enable the drills <NUM> to drill holes into the surrounding wall. The result is eight drilled holes <NUM>, spaced apart at the wall, as indicated by x, by around <NUM>.

Significantly, the ring <NUM> and drills <NUM> define an on-board rock support bolting system that can provide support while the mobile tunnel boring unit <NUM> is busy excavating. This results in a fully supported excavation, with the front shield <NUM> defining a primary support, and the roof bolts defining a secondary support. In addition, the mobile tunnel boring unit <NUM> includes one or more probe drills <NUM>, as best shown in <FIG>, safely housed within the rear shield <NUM>. This allows drilling in advance, typically up to <NUM> metres, to locate bad ground conditions and/or water ahead of the boring unit <NUM>. The probe drill position and orientation can be manually adjusted to allow cover drilling in three directions through the cutter head <NUM> and the front shield <NUM>. In an embodiment, as best shown in <FIG>, the rear shield <NUM> includes a plurality of fingers <NUM> that define gaps through which the drills <NUM> can extend and drill. These fingers <NUM> guide and assist in the drilling operation of the support drills <NUM>. The fingers <NUM> are hydraulically actuated to provide adjustment during transport and also to support the tunnel wall during support drilling, to protect the support drill operators <NUM> (as best shown in <FIG>).

Referring back to <FIG>, the first backup unit <NUM> is fitted with a second conveyor arrangement <NUM> to transport the cuttings and muck from the first conveyor arrangement <NUM> on the mobile tunnel boring unit <NUM> towards a second backup unit <NUM>. The first backup unit <NUM> is fitted with the main hydraulic power pack, and an electric panel that is equipped with a PLC system. The first backup unit <NUM> is also fitted with a scrubber unit to assist with dust suppression. In an envisaged arrangement, the second backup unit <NUM> is fitted with a third conveyor arrangement <NUM> to receive the cuttings and muck from the second conveyor arrangement <NUM> on the first backup unit <NUM> towards a truck <NUM>. In an embodiment, the second backup unit <NUM> is fitted with a cooling water circulation pumping system. The second backup unit <NUM> is also fitted with a main incoming transformer substation and also a dust extraction fan unit. Cable and hose reels are fitted as well to allow continuous operation for a distance of <NUM> meters. In addition, the first, second and third conveyor arrangements <NUM>, <NUM>, <NUM> are all collapsible, so as to improve and facilitate manoeuvrability, as shown in <FIG>, <FIG> and <FIG>. In particular, the end portions of the conveyor arrangements <NUM>, <NUM>, <NUM> can be folded or pivoted downwardly, as best shown in <FIG>, <FIG> and <FIG>. In addition, the conveyor arrangements <NUM>, <NUM>, <NUM> are designed with variable geometry, to enable them to be compacted to assist manoeuvrability during transportation. The conveyor arrangements <NUM>, <NUM>, <NUM> have a modular design to enable common parts inventory to ease spares and maintenance requirements.

Advantageously, the borer arrangement may be monitored and controlled remotely, and is thus safe for working personnel.

In use, turning now to <FIG>, and further below to <FIG>, the utilisation of relatively smaller components, when compared to traditional TBMs, means that after preparing a starting chamber for the borer arrangement, the borer arrangement can advance blind, typically according to a preprogramed route. Typically, with reference to <FIG>, a site is prepared by having a box-cut starting chamber <NUM> prepared, with a typical height of <NUM> meters and a length of around <NUM> metres. The site is further prepared by drilling supports for the chamber <NUM>, as shown by arrow <NUM>. Shuttering is then installed (arrow <NUM>) with an LHD truck, with concrete then being pumped by a truck mixer (arrow <NUM>). The compact design of the units <NUM>, <NUM>, <NUM> allows each one to be transported within existing tunnels and vertical shafts (i.e. each unit can fit into a standard cage), with all components being easily and quickly assembled and disassembled. Conveniently, in this regard, the various components of the invention are all designed to be no higher than <NUM> metres. In a transport configuration, in which the various segments of the cutter head <NUM> and the front and rear shields <NUM>, <NUM> are removed, the mobile tunnel boring unit <NUM> has a length of around <NUM> metres. In the boring configuration, which includes the cutter head <NUM> and the front and rear shields <NUM>, <NUM>, the mobile tunnel boring unit <NUM> has a length of around <NUM> metres.

Once the site has been prepared, with reference now to <FIG>, the machine sections are transported down the shaft in a cage, as shown by arrow <NUM>. Material may then be transported down a decline shaft, provided there is at least a <NUM> metre passage height, as shown by arrow <NUM>. In an embodiment, the cutter head <NUM> is detachably secured to the mobile tunnel boring unit <NUM> with a quick attachment method (described further below with reference to <FIG>, <FIG> and <FIG>), which improves the efficiency of the boring cycle. In addition, the cutter head <NUM> comprises a plurality of segments that can be pre-assembled and pre-installed, typically together with the front shield (described above and further below with reference to <FIG>, <FIG> and <FIG>). The centre segment <NUM> has a tapered profile to ensure accurate segment attachment, as described above. Thus, upon preparation, the front shield <NUM> (together with the cutter head <NUM>, as described above) can be pre-installed in the starting chamber <NUM>, as indicated by arrows <NUM> and <NUM> respectively. Once done, the starting chamber <NUM> is ready for the mobile underground tunnel borer arrangement <NUM> of the invention, as shown by arrow <NUM>.

<FIG> shows the components of the mobile underground tunnel borer arrangement <NUM> of the invention being transported down a decline shaft, again provided there is at least a <NUM> metre passage height, as shown by arrow <NUM>. The mobile underground tunnel borer arrangement <NUM> may then be assembled underground, in an adjacent chamber, as shown by arrow <NUM>. <FIG> shows the mobile tunnel boring unit <NUM> being moved into position and ultimately connected to the cutter head <NUM> and front shield <NUM> combination, along path <NUM>. <FIG> shows the first and second backup units <NUM>, <NUM> being moved into position behind the mobile tunnel boring unit <NUM>, to enable the boring cycle to commence. The boring cycle continues to enable the machine to advance, as described above, and as shown by arrow in <NUM> in <FIG>. As the muck and cuttings are conveyed rearwardly along the conveyors, muck is removed to a stockpile area by truck <NUM> (similar to truck <NUM> shown in <FIG>), with a replacement truck <NUM> (also similar to truck <NUM> shown in <FIG>) being ready to take its place so as to keep the process substantially continuous. The muck is then discharged at a stockpile area, as indicated by arrow <NUM> in <FIG>. Once the required tunnel length has been drilled, as shown by arrow <NUM>, the mobile tunnel boring unit <NUM> is disconnected from the cutter head <NUM> and front shield <NUM> combination, reversed out of the tunnel as indicated by arrow <NUM>, and then moved to a new pre-prepared site <NUM> in which another cutter head <NUM> and front shield <NUM> combination is waiting.

Turning now to <FIG>, the construction and use of a launching or starting frame <NUM> (shown in <FIG>), within a prepared starting chamber <NUM>, will now be described. Within the chamber <NUM>, a first centre base frame component <NUM> is placed down on the ground, spaced apart from the tunnel face <NUM> to be drilled, as shown in <FIG>. Thereafter, a number of additional centre base frame components <NUM> are fitted to the first centre base frame component <NUM>, typically using connection plates <NUM>, leading up to, so as to substantially abut against, the tunnel face <NUM>. This is shown in <FIG>. A number of side base frame components <NUM> are then fitted on either side of the assembled centre base frame components <NUM>, <NUM>, as shown in <FIG>, again typically using connection plates <NUM>. <FIG> shows the resulting assembled base <NUM> for the starting frame <NUM>.

As shown in <FIG>, a first side frame component <NUM> is secured to the side base frame component <NUM>, adjacent the tunnel face <NUM>, using rods <NUM>. A second side frame component <NUM> is secured to the opposite side base frame component <NUM>, adjacent the tunnel face <NUM>, using rods <NUM>, as shown in <FIG>. A cutter head backstop assembly <NUM> is provided to extend across the first and second side frame components <NUM>, <NUM>. A pair of cutter head backstop telescopic pipe supports <NUM>, <NUM> are fitted to upper regions of the first and second side frame components <NUM>, <NUM>, as shown in the views of <FIG>. As shown in <FIG> and <FIG>, a pair of mobile templates <NUM> are provided and fitted proximate the ends of the first and second side frame components <NUM>, <NUM>. As shown in <FIG>, a first pair of crawler track boards <NUM> are provided and fitted to the end of the assembled base <NUM>. <FIG> also shows a first cutter head segment <NUM> (corresponding to peripheral cutter head segment <NUM> shown in <FIG>) ready for installation.

Additional cutter head segments <NUM> are installed, piece by piece, to ultimately define an outer cutter head ring <NUM>, as shown in the views of <FIG>. The cutter head ring is supported on the first pair of track boards <NUM>. A central cutter head component <NUM> (corresponding to central cutter head segment <NUM> in <FIG>) is then fitted within the cutter head ring <NUM>, as shown in <FIG> (and the subsequent figures). As shown in <FIG>, a second pair of crawler track boards <NUM> are provided and fitted to the assembled base <NUM>, adjacent the first pair of track boards <NUM>. As shown in <FIG>, a front shield sector <NUM> is provided and supported on top of the second pair of track boards <NUM>. The front shield sector <NUM> is typically secured in position using pins <NUM>. Turning now to <FIG>, a pair of main drive cylinder components <NUM> are placed in position, adjacent the first and second side frame components <NUM>, <NUM>. This figure also show a third side frame component <NUM>, ready to be installed adjacent the first side frame component <NUM>.

A fourth side frame component <NUM> is also provided and installed, as shown in <FIG>. This figure also shows a front shield <NUM> ready to be installed, with <FIG> subsequently showing the front shield <NUM> fitted around the cutter head ring <NUM>. <FIG> also shows a third pair of crawler track boards <NUM> provided and fitted to the assembled base <NUM>, adjacent the second pair of track boards <NUM>. This figure also show a fifth side frame component <NUM>, ready to be installed adjacent the third side frame component <NUM>. A sixth side frame component <NUM> is also provided and installed, as shown in <FIG>. This figure also shows a fourth pair of crawler track boards <NUM> provided and fitted to the assembled base <NUM>, adjacent the third pair of track boards <NUM>. The result is the now assembled starting frame <NUM>. In use, turning now to Figure 20U, once the starting frame <NUM> has been assembled, mobile tunnel boring unit <NUM> (in its transport configuration, as described above) is brought closer. A tail shield <NUM>, corresponding substantially to the rear shield <NUM> described above, is provided and fitted on top of the boring unit <NUM>, as shown in Figure 20V. Finally, as shown in Figure 20W, the mobile tunnel boring unit <NUM> is driven into the starting frame <NUM>, connected to the central cutter head component <NUM>, and is now ready to operate, as described above.

To assist in the assembly of the cutter head <NUM> and shield segments <NUM>, <NUM>, <NUM> and <NUM> (as shown in <FIG>, <FIG>) inside the starting frame <NUM>, a manipulator <NUM> is provided for use by a telehandler <NUM>, as shown in <FIG>. The telehandler <NUM> is hydraulically powered and remote controlled. The manipulator <NUM> is arranged to pick up a component <NUM> corresponding to any of the cutter head and/or shield segments, drive the component <NUM> into the starting frame <NUM>, and place it where required to facilitate the assembly or connection of the relevant component <NUM>.

The manipulator <NUM> is shown in more detail in <FIG>, and typically comprises a rear plate <NUM> having an elongate support <NUM> that can be grabbed and lifted by a hooking arrangement <NUM> at the end of the telehandler <NUM>. A support arrangement extends from the front of the rear plate <NUM>, comprising a pair of spaced support plates <NUM>, <NUM>. A securing plate <NUM> is fitted across the ends of the support plates <NUM>, <NUM>, the securing plate <NUM> being pivotable relative to the support plates <NUM>, <NUM>, to enable the relevant component <NUM> to be placed where required.

The tunnel borer arrangements of the present invention is far more mobile and versatile than traditional TBMs of the type described above, and is relatively cheaper. In addition, the use of various interchangeable components greatly simplifies maintenance, thereby increasing overall efficiency of the machine.

Claim 1:
A mobile tunnel boring unit (<NUM>), wherein the unit (<NUM>) comprises:
a support body (<NUM>) driven by first drive means (<NUM>), the first drive means (<NUM>) for driving the mobile tunnel boring unit (<NUM>) including a pair of spaced apart crawler tracks (<NUM>) in contact with the tunnel floor (<NUM>) and related track driving means (<NUM>) to move the tracks (<NUM>), and thus the support body (<NUM>);
a cutter head drive means (<NUM>) located at an operatively front end of the support body (<NUM>), to which is fitted a rotatable cutter head (<NUM>) that has been pre-installed in a starting chamber (<NUM>, <NUM>), proximate a tunnel face (<NUM>, <NUM>) to be bored, so as to rotatably drive the rotatable cutter head (<NUM>), in use;
a muck hopper (<NUM>) and a first conveyor arrangement (<NUM>), the cutter head (<NUM>) comprising a full face cutter head (<NUM>) fitted with cutters to bore a tunnel face (<NUM>, <NUM>), the cutter head (<NUM>) being arranged to allow cuttings to pass through the cutter head (<NUM>) for discharge into the muck hopper (<NUM>) and onto the first conveyor arrangement (<NUM>), the cutter head drive means (<NUM>) and a rear portion of the cutter head (<NUM>) defining aligned central apertures (<NUM>, <NUM>) through which a front part of the first conveyor arrangement (<NUM>) can extend;
a telescopic shield arrangement (<NUM>) to shield the boring unit (<NUM>), the shield arrangement (<NUM>) comprising a front shield (<NUM>) proximate the front of the mobile tunnel boring unit (<NUM>), from which the cutter head (<NUM>) protrudes and for accommodating the cutter head drive means (<NUM>), the front shield (<NUM>) also having been pre-installed in the starting chamber (<NUM>, <NUM>) together with the cutter head (<NUM>), and a rear shield (<NUM>) that surrounds at least an upper portion of the mobile tunnel boring unit (<NUM>), the front and rear shields (<NUM>, <NUM>) operating telescopically relative to each other, to accommodate changes in the boring direction; and
an actuating arrangement (<NUM>) comprising a plurality of hydraulic thrust cylinders (<NUM>) extending between the cutter head drive means (<NUM>) and a pair of opposite first gripper assemblies (<NUM>).