EP1094198A2

EP1094198A2 - A method for drilling an underground tunnel

Info

Publication number: EP1094198A2
Application number: EP00870241A
Authority: EP
Inventors: Paul Kips
Original assignee: Smet-Tunnelling
Current assignee: Smet-Tunnelling
Priority date: 1999-10-21
Filing date: 2000-10-23
Publication date: 2001-04-25
Also published as: EP1094198A3

Abstract

The invention relates to a method and a device (1) for drilling an underground tunnel (35) with a tunnel wall (33), the device (1) comprising a drill head (2) for drilling ground and a driving (7) for driving the drill head (2). The device comprises a coating device (20) for forming a casing (32) for the tunnel wall (33), the coating device (20) comprising a formwork (34) with an outer face (36) facing the tunnel wall (33) and a device for supplying a coating material in a viscous state to an ejection nozzle (39) for ejecting the coating material in a space between the tunnel wall (33) and the outer face (36) of the formwork (34), the ejection nozzle (39) being rotatably mounted to allow the casing to be applied against at least part of the tunnel wall (33). The drilling device (1) further comprises an expandable gripping device (10) for pushing the drilling device off against the tunnel wall (33).

Description

The present invention relates to a device for drilling an underground tunnel as described in the preamble of the first claim.
According to the state of the art, horizontally or slightly slanting underground tunnels are drilled between a starting well and an end well, by means of a drilling device with a drill head for excavating the ground. After it has been mounted in the starting well, the drilling device is forwarded in the direction of the end well while excavating ground to form the tunnel. After a first tunnel length has been excavated, a casing is applied against the freshly drilled tunnel wall. As a casing, often use is made of a plurality of subsequent pipes made of concrete material, which fit against each other and extend in longitudinal direction of the tunnel. A first pipe is introduced into the tunnel by inserting the pipe in such a way that its front end faces the drill head, the back end of the pipe facing the starting well. As the drill head is advanced towards the end well, each time an additional pipe is added to the back end of a former pipe, and the plurality of pipes is advanced in the direction of the end well. This means in fact that the entire casing needs to be advanced through the tunnel, until the first pipe of the casing reaches the end well. The end well is only there to allow recuperation of the drilling device.
The energy required to advance the plurality of pipes through the tunnel depends on the tunnel length as well as on the friction forces occurring between the wall of the pipes and the tunnel wall. To keep these friction forces as low as possible, often the diameter of the tunnel is over-sized with respect to the external diameter of the pipes.
The method known from the art however presents the disadvantage that the oversize of the tunnel cannot be maintained sufficiently long to allow displacement of the pipes until the front pipe reaches the end well. It has namely been found that in certain types of soils, in particular in converging grounds such as clay, the ground surrounding the tunnel wall expands thus exerting a pressure to the tunnel wall. As a result, its diameter starts decreasing rapidly, until the oversized space has disappeared. As a consequence of the decreasing diameter, friction forces will increase when advancing the plurality of pipes through the tunnel, thus leading to an increased power required to allow the plurality of pipes to be displaced through the tunnel. This limits the pipe length that can be driven through the tunnel already within a relatively short period of time after the tunnel has been drilled.
It is the aim of this invention to provide a device with which the problem of the rapidly increasing friction forces when forming the tunnel casing, can be overcome.
This is achieved with the technical features of the characterising part of the first claim.
The device of this invention comprises a coating device for forming a casing for and against the tunnel wall. The coating device comprises a formwork with an outer face facing the tunnel wall and a device for supplying a coating material in a viscous state to a space between the tunnel wall and the outer face of the formwork. The coating material is preferably supplied through an ejection nozzle, which is rotatably mounted within the coating device to allow the coating to be applied and the casing to be formed against at least part of the tunnel wall, taken in circumferential or radial direction of the tunnel.
The use of the formwork permits to obtain a casing with an even, smooth surface, which cannot be achieved by the generally known spraying techniques. Simultaneously concrete loss can be limited, as falling of concrete from the top and side parts on the bottom part of the tunnel is counteracted.
To overcome blocking of the formwork in the tunnel after the tunnel has been finished and to allow the formwork to be recuperated, the formwork is shrinkable. The formwork is preferably also expandable to allow it to be used with tunnels of varying diameters.
In a preferred embodiment, the coating device and preferably also the formwork comprise means for displacing them within a.o. the tunnel. In that way, the coating device and preferably also formwork may be advanced to a subsequent tunnel part the wall of which has not yet been coated after the wall of a first tunnel part has been coated.
The present invention also relates to a device for drilling underground tunnels, in particular horizontally extending or slightly slanting tunnels.
According to a state of the art method for drilling a tunnel, a drilling device is placed into the starting well. The front surface of the drill head of the drilling device is pressed against the wall of the starting well. As the drill head is rotated, ground is excavated in front thereof and evacuated from the thus drilled hole. In that way a tunnel is formed. To allow that a sufficiently high pressure is exerted by the drill head and to allow the drilling device to be advanced through the ground to excavate the tunnel, the drilling device must be capable of pushing itself off against a support. In the state of the art method, the drilling device is pushed off against the tunnel lining, for example the front rim of the pipe closest to the drilling device in case the lining is formed by a plurality of pipes. However, this technique cannot be used when the casing is made by spraying mortar or concrete in the viscous state between a formwork and the tunnel wall, as the sprayed material will need some time to harden and as the drill head is advanced before it has hardened to a sufficient extent.
This problem is solved by the present invention in that the drilling device of this invention comprises a drill head for drilling the ground, a driving for driving the drill head and means for pushing off the drill head, comprising a gripping device which is provided to be clamped against the tunnel wall in radial direction of the tunnel wall.
As appears from these technical features, the drilling device is capable of pushing itself off in radial direction against the tunnel wall. The reaction forces needed to withstand the thrust force of the drill head needed to advance the drilling device must not be absorbed by the tunnel casing, but are rather absorbed by the tunnel wall itself and the ground surrounding the tunnel wall. The transfer of the reaction forces to the ground surrounding the tunnel has the effect that inward expansion of the ground towards the tunnel may be prevented, thus counteracting converging of the ground and shrinking of the tunnel diameter. It has been observed that the pushing off of the drilling device in radial direction against the tunnel wall entails the advantage that deviation of the drilling device from its planned advancing direction can be minimised, thus minimising the extent to which advancing of the drilling device must be corrected in the course of the drilling operation.
To facilitate the displacement of the gripping device through the tunnel the gripping device is preferably shrinkable and preferably also expandable in radial direction of the tunnel, in such way that a circumferentially closed structure is obtained for a range of the diameter. As the size of the gripping is variable, it is suitable for use with tunnels of varying diameters.
To allow expansion and shrinking of the gripping device to take place, the gripping device preferably comprises a housing with a central axis and a wall which is divided in a plurality of shells in radial direction of the housing. Each shell is moveably mounted towards and from the centre of the housing. To ensure that the housing of the gripping device may form a closed unity, the gripping device comprises means for filling a gap between adjacent shells, which means are preferably movable in radial direction of the housing. The means for filling a gap between adjacent shells preferably comprise a wedge or any other means known to the man skilled in the art. The wedge may be displaced through the action of a hydraulic jack or any other means known to the man skilled in the art. Upon the action of the hydraulic jacks the shells are forced to fit against the tunnel wall. As the housing of the gripping device is forced to fit against the tunnel wall, the reaction force needed to allow advancement of the drill head through the ground may be transferred to the tunnel wall, through friction of the shells against the tunnel wall. As the reaction forces to the drilling action are transferred to the surrounding ground, relatively large overburden loads may be absorbed by a relatively light gripping device.
The thrust jacks are preferably mounted inside the housing of the gripping device, thus limiting the length of the drilling device, which in turn leads to a reduced thrust ting force.
To solve the problem of an unwanted deviation or roll of the drill head from the axial direction of the tunnel in the course of the drilling action, the drilling device of this invention comprises a drill head with a cutter wheel for drilling into the ground, the cutter wheel comprising at least two concentric wheels which are rotatably mounted in such a way that they are rotatable in opposite directions.
The presence of two concentric wheels provided to rotate in opposite directions permits that the reaction force of the couples driving the wheels may compensate each other. Due to this compensation, the weight of the drill head may be reduced without this going at the expense of the accuracy of the drill head, thus rendering the drilling device easier to handle. Simultaneously friction of the device with the surrounding tunnel walls and pushing off of the device against the tunnel wall can be minimised, as this friction is no longer required to compensate the deviation.
This way of preventing roll of the drill head is of particular importance in case of a full face digging device where the entire front face of the cutter wheel is provided to contact and dig the ground and rather large reaction forces are needed to allow advancing of the drilling device. Roll of the cutter wheel and drill head from the planned axial direction of the tunnel is mostly caused by these reaction forces, the roll becoming increasingly important with smaller, lighter devices. In state of the art devices, the problem of unwanted roll is solved by alternatively rotating the cutter wheel clockwise and counter-clockwise. However this has the disadvantage that with light machines, rotation of the drill head needs to be interrupted and reversed frequently to reverse the direction of rotation, which involves a significant loss of time.
In a preferred embodiment of the invention, each of the wheels is connected to its own driving device, the rotation speed of each of the wheels being individually adaptable. As deviation of the advancing direction of the drill head from the axial direction of the tunnel depends on the rotation speed of the drill head or cutter wheel, which in turn may vary with the composition and constitution of the ground that is drilled, deviation can be counteracted by adapting the rotation speed of each wheel.
Roll of the drilling device of this invention form a planned track is reduced in that the device comprises a roll detector for detecting the roll of the drill head from the axial direction of the tunnel or a planned advancing direction of the drill head, and in that the roll detector is coupled to the drill head and is provided to control rotation, rotation speed and direction of rotation of each wheel. The presence of these features permits roll to be compensated immediately, in an automatic manner.
An improved control of the advancing direction of the drilling device results from the presence in the drill head of at least two teeth which are cantably mounted with respect to the drill head. The teeth are cantable between a first retracted position in which they fit to the drilling device and a second position in which they extend from the drilling device. In the extended position the diameter of the ground drilled by the drill head is increased, so that the direction in which it is displaced may be adapted towards the preferred direction. This is a new way of driving a drill head.
The position of each tooth is preferably individually controllable along the circumference of the shield, to allow the displacement correction in various directions. The cantable mounting of the teeth further allows the diameter of the drilled part to be extended to a smaller or larger extent, which may be of particular importance in the case of converging grounds when it is advisable to control the time at which the ground contacts the casing. The axis of the cutter wheel remains a central axis of the drill head, however the cutting diameter of the cutter wheel is enlarged to create a preferred movement direction of the drill head.
Controlling the advancing direction of the drilling device is particularly important in ground layers with a non-homogeneous composition. As the drill head will preferably take the easiest way, it will deviate from the planned direction so that its advancing direction needs correction. The present solution is particularly suitable for use in smaller drilling devices (i.e. devices for drilling tunnels with a diameter of less than approximately 1.6 m), in combination with a cutter wheel with at least two concentric mounted rings. The present technical features provide a simplified system for controlling the advancing direction and are of particular importance in case it is desirable to recuperate the drilling devices after the tunnel has been finished.
To facilitate removal of the ground that has been drilled away, preferably a plurality of teeth are mounted on the cutter wheel, each tooth comprising an ejection nozzle which is connected to a supply for an anti-adhesive for the ground. By injecting an anti-adhesive in the course of the drilling action, the ground grains become coated with the anti-adhesive as they are formed. In that way it is possible to prevent that ground grains stick together, so that discharge thereof is facilitated.
Another way to facilitate discharge of the drilled ground can be achieved in that the cutter wheel has a diameter and the drilling device comprises means for temporarily enlarging the diameter of the cutter wheel. Thereto the drilling device comprises at least one tooth which is cantably mounted within the housing of the drilling device, in such a way that when the tooth is canted, it extends with respect to the cutter wheel.
The drilling device of this invention comprises a front part and a back part taken in longitudinal direction of the tunnel, the front and back part being electrically isolated from each other and being coupled to opposite charges of an electric power supply. In particular, the drill head and the gripping device are electrically isolated from each other and are coupled to opposite charges of an electric power supply. Thereby preferably the drill head is coupled to a cathode and the gripping device is coupled to an anode of the electric power supply. These technical features provide a solution to the problem that in the course of a drilling operation the drill head may become blocked due to various reasons, when the available power is smaller than the power required to advance the drill head. The coupling to opposite charges of an electric power supply involves that an electro-osmosis effect is created in the ground, as a consequence of which water pressure is locally increased and water is forced to flow through the ground. The local increase of the water pressure results in an alteration of the soil charcteristics such as a decreasing shear resistance. The pressure at a specific position in the ground is namely proportional to the weight of the ground laying on top of that position and is the sum of the particle pressure and the water pressure. The shear resistance in turn is proportional to the particle pressure.
Connection of the drill head to a cathode and the gripping device to an anode involves a water flow from the gripping device where the ground is dehydrated and thus fortified, towards the drill head where the ground is humidified and thus weakened.
The invention will be further described in the following figures and description thereof.
Figure 1a is a cross section of the drilling device head and the gripping device of this invention.
Figure 1b is a cross section of the coating device, the front end of which is provided to be coupled to the back end of the gripping device.
Figure 2 is a cross section of the gripping device of this invention.
Figure 3a is a cross section in longitudinal direction of the coating device of this invention. Figure 3b is a cross section in cross direction.
Figure 4a shows a view to the teeth for use with the cutter wheel, figure 4b is a cross section of the drill head with the teeth for use with the cutter wheel.
Figure 5a is a cross section of a tooth mounted on a spoke of the cutter wheel.
Figure 6 is a view to a tooth with ejection nozzle mounted on a spoke of the cutter wheel.
Figure 7 is a cross section of the electro-osmosis system of the invention.
The drilling device 1 shown in figure 1a comprises a drill head 2 and a gripping device 10. The drill head 2 is rotatably mounted around an axis 5 of a housing 6, and is provided to drill away ground to form an underground tunnel. The drill head 2 may have various shapes, the shape mostly being adapted or adaptable to the type of ground that needs to be drilled. The drill head may have a conical shape, have a flat drilling surface or be an inwardly turned cone.
The drill head 2 contains a cutter wheel comprising a first 3 and second 4 concentric mounted cutter wheel. If so desired for specific applications, the drill head 2 may comprise more cutter wheels. The first and second cutter wheel 3, 4 are rotatable around the axis 5. Preferably the first and second cutter wheels 3, 4 are coupled to an individual driving, so that their direction of rotation and rotation speed are individually controllable. The first and second cutter wheel 3, 4 are provided to be rotated in opposite directions, but may also be rotated in the same direction. The rotation direction of each cutter wheel is preferably reversible. As the drill head 2 is rotated, ground is drilled away and the drilling device is advanced through the ground while forming a tunnel. The device of this invention is particularly suitable for the drilling of horizontal or slightly slanting underground tunnels of widely varying sizes.
The gripping device 10 (figure 2) functions as a means for pushing off the drill head 2 against the tunnel wall, and to provide the reaction forces needed to allow the drill head 2 to be advanced and to withstand the thrust force of the drill head 2. The gripping device 10 is preferably both expandable and shrinkable in radial direction of the device. The preferred embodiment of the gripping device 10 of this invention shown in figure 2, comprises a housing 11 with a central axis 15, which preferable coincides with the axis of the drilling device 1. As can be seen from figure 2 which shows the gripping device 10 in a partly expanded situation, the wall of the housing 11 is in radial direction divided in a plurality of shells 12. Each shell 12 is moveably mounted towards and from the axis 15, on at least two hydraulic jacks 13. Each shell 12 may be individually moveable, or the jacks 13 may be moveable all together or in pairs. Depending on the size thereof, a plurality of hydraulic jacks 13 may be provided in length direction of the housing 12 of the gripping device 10. To fill the gap between adjacent shells 12 when in expanded position, the gripping device 10 further comprises wedges 16. Preferably a wedge 16 is provided between each pair of adjacent shells 12, to provide a virtually completely closed circumference in the working situation. All or part of the wedges 12 are moveably mounted on hydraulic jacks 14, which control the displacement of the wedges. In stead of hydraulic jacks 13, 14 other means generally known to the man skilled in the art for driving the shells 12 and wedges 16, may be used.
The above described technical features allow the shells 12 to be forced against a tunnel wall, so that the gripping device 10 may be clamped against the tunnel wall 33 in radial direction thereof and the reaction forces needed to allow advancement of the drill head through the ground may be transferred to the tunnel wall through friction between the shells 12 and the tunnel wall. As the shells 12 and wedges 16 are displaceable, the size of the gripping device in cross direction of the tunnel is variable, so that the gripping device 10 may be adapted to fit against the tunnel wall 33 as a closed unity and is suitable for use as a support in the building of tunnels with widely varying diameters. Due to the closed circumference, even gripping devices with a light construction are capable of withstanding large ground strains. Also, the gripping device is capable of fulfilling its function irrespective of the reaction of the surrounding ground to the drilling action, and variation of the diameter of the drilled hole as a consequence thereof. In converging grounds namely, the diameter of a drilled hole is not univocally defined, if a period of time has expired between the drilling of the hole and the positioning of the gripping device 10. The diameter is namely determined by a.o. the ground characteristics, drilling speed, possible drilling interruptions, the presence of other constructions.
The mounting of the thrust jacks 13, 14 in the housing 11 allows the length of the housing to be minimised. The dimensions of the gripping device 10 in radial direction, when in the contracted situation are preferably such that the device may be removed from the tunnel without touching or damaging the tunnel wall 33.
The drilling device 1 of this invention preferably comprises or is connected to a roll detector (not shown) for detecting roll of the drill head 2 from the axial direction of the tunnel 33 or a planned advancing direction of the drill head 2. The roll detector is provided to control the direction and speed of rotation of each cutter wheel 3, 4 to permit that roll of the drilling head 2 may be compensated immediately, in an automatic manner. Preventing roll has constructive advantages and is particularly important with this invention as the driving of the drilling device does not contact the tunnel casing as is done in the state of the art to absorb and compensate roll.
An improved possibility to correct or control the displacement direction of the drilling device 1 is provided by the presence of at least one cutting tooth 9, which is extendable with respect to the outer rim 8 of the outer cutter wheel 4 of the drill head 2 (figure 4). The teeth 9 are preferably mounted in the housing 6 in the vicinity of the cutter wheels 3, 4.
Thereto, the teeth 9 may for example be cantably mounted within the drilling device 1. This can be achieved by mounting the teeth 9 on an axis, which is perpendicular to the spokes 8 of the cutter wheel 3, 4 and parallel to the drilling front drilled by the drilling head 2. A plurality of teeth 9 may be present, the teeth being preferably being evenly distributed over the circumference of the housing 6 and drill head 2. The cantable mounting of the teeth 9 allows the diameter that is drilled by the drill head 2 to be extended to a varying extent, depending on the canting of the teeth 9. The shape of the teeth 9 is chosen such that they cut the ground when canted. This may be of particular importance in the case of converging grounds when it is advisable to control expansion of the ground towards the drilled tunnel. Enlarging of the cutting diameter of the cutter wheel 3, 4 may also assist in creating a preferred movement direction of the drill head 2, which is particularly important in ground layers with a non-homogeneous composition. As the drill head 2 will preferably follow the easiest track, it will deviate from the planned direction so that its advancing direction needs correction.
With the present solution to enlarge the diameter that may be drilled by the drill head 2 and to control the advancing direction of the drill head 2, the size of the drilling device may be reduced thus facilitating recuperation of the drilling device through the tunnel after it has been finished.
As can be seen from figure 1a, the cantable mounting of the teeth 9 is obtained in that an end 19 of the teeth 9 pointing away from its cutting edge 21 is bevelled off and is supported by a ring 22 mounted against the inner wall 26 of the housing 6. The surface of the ring 22 is complementary to the bevelled surface 19 of the tooth 9, and is preferable bevelled off from the back of the housing 6 in a direction pointing towards the drill head 2. The ring 22 is moveable in longitudinal direction of the housing 1. Canting of the teeth 9 is obtained by moving the ring 22 towards the drill head 2. As the ring 22 is moved towards the drill head, the teeth are forced to cant and extend from the cutter wheel. Movement of the ring 22 may be controlled by a controller of the device and/or by the roll detector 23. The position and canting of each tooth 9 may be individually controllable to allow the displacement correction in various directions.
When drilling an underground tunnel, the ground that has been drilled away needs to be evacuated from the tunnel. Usually dry discharge of the ground is done by means of an air flow, which is however not evident in case large distances have to be overcome. The ground particles having an uneven shape show a tendency to stick together or to the discharge pipe, which may involve clogging of the discharge pipe. Discharging of the particles based on water as a transport medium can often not be used, in particular not with soils which absorb and swell in water.
This problem may be solved by mounting onto the spokes of the cutter wheel 3, 4 a plurality of teeth 24 with at least one ejection nozzle 25 for ejecting an anti-adhesive for the ground (figure 6). The anti-adhesive may be a gas or a liquid. Application of the anti-adhesive to the ground particles involves that the grains become coated with the anti-adhesive as they are formed, so that sticking of the ground is prevented and discharge thereof is facilitated. Each ejection nozzle is connected to a supply for the anti-adhesive.
This problem may also be solved by the presence of a plurality of teeth 24 mounted in a cantable manner on the spokes of the cutter wheel 3, 4 (figure 5). Thereto each tooth 24 comprises a recess 26 provided to receive the spoke 18. Spoke 18 and recess 26 have a rounded surface as a result of which tooth 24 may freely rotate with respect to spoke 18, which functions as the rotation axis. Each tooth 24 is essentially V-shaped and comprises a first and a second tip 27, 28 with cutting edges 29 and non cutting edges 30. With such teeth left-wise rotating as well as right-wise rotating drilling can be done. The rotation of the teeth 24 is not mechanically determined, but is implied by the shape thereof. As the cutting edge of the teeth 24 is automatically oriented towards the surface that needs to be drilled when it contacts this surface, wearing of the teeth 24 and adverse alterations of the ground characteristics can be prevented.
The drill head 2 and gripping device 10 are preferably connected to opposite charges of an electric power supply 31. This allows to solve the problem of blocking of the drill head 2 in the course of a drilling operation, when the available power is smaller than the power required to advance the drill head. The coupling of the drill head 2 to the cathode and the gripping device 10 to the anode induces an electro-osmosis effect in the ground, as a consequence of which water is forced to flow towards the drill head 2 where the ground is humidified, weakened and thus loosened. At the position of the gripping device 10 the water pressure decreases, thus increasing the pressure exerted by the ground particles, which in turn leads to an increasing shear resistance. The particle pressure is namely proportional to the shear resistance. In that way, a blocked drill head 2 may be unblocked.
The division of the cutter wheel into at least two concentric cutter wheels 3, 4 and the shrinkable construction of the gripping device allow that the drilling device of this invention may be recuperated through the tunnel formed by it, without necessitating an end well for the recuperation of the device. This allows a serious cost saving.
As can be seen from figures 1b and 3, the present invention also relates to a coating device 20 for applying a casing 32 to at least part of the wall 33 of the tunnel 35. The coating device 20 may be coupled to the drilling device 1 or not. The coating device 20 comprises a formwork 34 with an outer face 36 provided to face the drilled tunnel wall 33, and an inner face 37 facing the tunnel 35. The fromwork 34 is preferably driven by the driving 7 of the drill head 2, to allow that both are advanced at the same speed and to minimise interference of converging ground as far as possible. It is however also possible to drive the drill head 2 and fromwork 34 by a separate driving. The coating device 20 further comprises means 38, preferably a spraying device 38, for applying a coating in the viscous state between the outer face 36 of the formwork and the tunnel wall 33. The coating device 20 comprises a supply 38 for supplying the coating material 32 towards an ejection nozzle 39, the ejection nozzle 39 being displaceably mounted in such a way that it is capable of applying the coating to at least part of the tunnel wall 33 taken in radial direction of the tunnel 35. Thereto, the ejection nozzle 39 may for example be mounted on a rotatable arm 40. The arm 40 is preferably rotatable over 360° to allow that a coating can be applied over the circumference of the tunnel wall 33, but it may be rotatable to a smaller extent. The coating is preferably applied by spraying or ejection of the viscous mass. As a viscous mass often use is made of concrete or mortar. The casing 32 is formed by inserting a formwork 34 in the tunnel 35, the shape of the formwork 34 corresponding to the shape of the casing 32 to be constructed.
To prevent sticking of the formwork 34 to the casing 32, the formwork 34 will be continuously advanced as the coating material is applied, at low speed. The coating is preferably applied by spraying or ejection of the viscous mass.
To prevent that the formwork 34 gets blocked in the tunnel 33 after the casing 32 has been constructed, the formwork is preferably expandable and shrinkable. The formwork can than be retracted from the finished tunnel casing after it has been shrunk, to prevent that is contacts the casing 32 and the casing 32 would get damaged. The fromwork has a back end 41 which is preferably slightly conical to prevent that the formwok gets blocked into the tunnel 33.
The present invention also relates to a the method for drilling a tunnel length. Thereto, the drilling device is inserted in a starting well. The drill head 2 is rotated, cutting wheel 3, 4 rotating in opposite directions and at a speed adapted to the constitution of the ground. If necessary, the ring 22 is advanced to cant the teeth 9 and to allow the drilled diameter to be enlarged. To facilitate removal of the ground, an anti-adhesive is ejected into the ground through the teeth 24. Upon rotation of the cutter wheel 3, 4, the teeth 24 are automatically canted with their cutting edge 29 facing the ground to be removed. The ground that has been drilled away is evacuated from the tunnel. As the drill head rotates, it is advanced and an increasing tunnel length is created. As the drill head 2 advances through the tunnel 35, the gripping device 10 is expanded to be spanned within the tunnel, to provide the reaction forces needed to allow the drill head 2 to be advanced. Thereto, the shells 12 and wedges 16 are moved to fit against the tunnel wall 33 and to form a closed unity. After a tunnel length has been excavated, the gripping device is crimped and moved forward into a newly drilled tunnel part. The gripping device may also be continuously moved throughout the tunnel to follow the drill head 2. At the back end of the gripping device 10, a formwork 34 is inserted into the tunnel. A coating in a viscous state is sprayed in the space remaining between the outer wall 36 of the formwork 34 and the tunnel wall 33. The coating is allowed to harden to form the casing 32. As a coating preferably use is made of concrete, or mortar in the viscous state.
After the wall of a first tunnel part has been coated, the formwork is advanced to a subsequent tunnel part the wall of which has not yet been coated. To prevent sticking of the formwork to the casing, the formwork will be continuously advanced, at low speed.
Reference list.
1. drilling device
2. drill head
3. first cutter wheel
4. second cutter wheel
5. axis of the drilling device
6. housing
7. driving
8. outer rim drill head
9. cantable cutting tooth
10. gripping device
11. housing
12. shell
13. hydraulic jack for a shell
14. hydraulic jack for a wedge
15. axis of gripping device
16. wedge
17. front end
18. spoke of cutter wheel
19. tooth end
20. coating device
21. cutting edge
22. ring
23. roll detector
24. tooth
25. nozzle
26. recess
27. first tip
28. second tip
29. cutting edge
30. non-cutting edge
31. electric power supply
32. casing
33. tunnel wall
34. formwork
35. tunnel
36. outer wall formwork
37. inner wall formwork
38. electric power supply
39. ejection nozzle
40.arm
41.back end

Claims

A device (1) for drilling an underground tunnel (35) with a tunnel wall (33), the device (1) comprising a drill head (2) for drilling ground and a driving (7) for driving the drill head (2), characterised in that the device comprises a coating device (20) for forming a casing (32) for the tunnel wall (33), the coating device (20) comprising a formwork (34) with an outer face (36) facing the tunnel wall (33) and a device for supplying a coating material in a viscous state to an ejection nozzle (39) for ejecting the coating material in a space between the tunnel wall (33) and the outer face (36) of the formwork (34), the ejection nozzle (39) being rotatably mounted to allow the casing to be applied against at least part of the tunnel wall (33).
A drilling device as claimed in claim 1, characterised in that the formwork (34) has a frusto conical front end at a side facing the drill head (2).
A drilling device as claimed in claim 1 or 2, characterised in that the formwork (34) is displacably mounted.
A drilling device as claimed in any one of claims 1- 3, characterised in that the device (1) comprises means for pushing off the drill head (2) to allow the drill head (2) to advance through the ground, the means for pushing off the drill head comprising a gripping device (10) provided to be clamped in radial direction within the tunnel (35) against the tunnel wall (33).
A drilling device as claimed in claim 4, characterised in that the gripping device (10) is expandable and shrinkable in radial direction of the tunnel (35).
A drilling device as claimed in claim 4 or 5, characterised in that the gripping device (10) comprises a housing (11) with an axis (15) and a wall of a plurality of shells (12), each shell (12) being moveable towards and from the axis (15), the device further comprising means (14, 16) for filling a gap between adjacent shells (12).
A drilling device as claimed in claim 6, characterised in that the means for filling a gap between adjacent shells (12) comprise at least one wedge (16), the wedge (16) being movable upon action of a hydraulic jack (14).
A drilling device as claimed in any one of claims 1- 7, characterised in that the drilling head (2) comprises a rotatable cutter wheel (3, 4) for drilling the ground, the cutter wheel (3, 4) containing at least a first (3) and a second (4) concentric cutter wheels, each wheel being connected to an individual driving for rotatably driving the wheel, the wheels (3, 4) being provided to rotate in opposite directions.
A drilling device as claimed in claim 8, characterised in that each cutter wheel (3, 4) is provided to be rotated at a rotation speed, the rotation speed of each cutter wheel (3, 4) being individually controllable.
A drilling device as claimed in claim 8 or 9, characterised in that the driving of each wheel is coupled to a roll detector (23), the rotation speed of each wheel being controlled by the roll detector.
A drilling device as claimed in any one of claims 8-10, characterised in that the cutter wheel (3, 4) has a diameter and comprises means (9) for enlarging its diameter.
A drilling device as claimed in claim 11, characterised in that the means for enlarging the diameter of the cutter wheel (3, 4) comprise at least one tooth (9) which is cantably mounted within the housing (6) of the drilling device (1).
A drilling device as claimed in any one of claims 8-12, characterised in that on the cutter wheel (3, 4) a plurality of teeth (24) are mounted, each tooth (24) comprising an ejection nozzle (39) for ejecting an anti-adhesive for ground particles.
A drilling device as claimed in any one of claims 1-10, characterised in that each tooth (24) is cantably mounted on a spoke of the cutter wheel (3, 4), each tooth (24) being essentially V-shaped and comprising a first and a second tip (27, 28) and a first and second outer cutting edge (29) for cutting the ground.
A drilling device as claimed in any one of claims 1-11, characterised in that the drill head (2) and the gripping device (10) are electrically isolated from each other and are coupled to opposite charges of an electric power supply (31).
A drilling device as claimed in claim 12, characterised in that the drill head (2) is coupled to a cathode and the gripping device (10) is coupled to an anode of the electric power supply.
A method for drilling an underground tunnel with a tunnel wall which is covered by a casing, in which method a drilling device comprising a drill head is advanced underground to drill a tunnel length in ground, whereafter a casing part is applied to at least part of the wall of the tunnel length, characterised in that the casing part is formed by inserting in the tunnel a formwork with an outer face facing the tunnel wall, spraying a viscous coating between the outer face of the formwork and the tunnel wall and hardening the coating to form the casing.
A method as claimed in claim 17, characterised in that when spraying the coating, use is made of a spray head which is rotated to allow a casing to be applied against at least part of the tunnel wall in circumferential direction of the tunnel wall.
A device for applying a casing to an underground tunnel wall, characterised in that the device comprises a formwork with an outer face facing the tunnel wall, means for supplying a coating for forming the casing between the outer face of the formwork and the tunnel wall, the means for supplying the coating being displaceably mounted to allow the coating to be applied such that at least part of the tunnel wall is covered in radial direction of the tunnel.