GB1576269A

GB1576269A - Tunnel drive shield

Info

Publication number: GB1576269A
Application number: GB4209177A
Authority: GB
Original assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Current assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Priority date: 1976-10-15
Filing date: 1977-10-10
Publication date: 1980-10-08
Also published as: DE2646586A1; DE2646586C3; DE2646586B2

Description

(54) TUNNEL DRIVE SHIELD (71) We, GEWERKSCHAFT El8ENHUTTE WESTFALIA, a body corporate, organised and existing under the laws of Federal Republic of Germany of 4670 Lunen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a drive shield, and in particular to a drive shield which can be used for driving tunnels in hard rock or stone in an underground mine working. Throughout this specification, the term "tunnel" or "tunnels" is intended to include galleries, trenches, adits or other similar elongated excavations.

In order to drive tunnels in loose or cohesive types of ground, it is known to use drive shields having a generally cylindrical cross-section. Drive shields in the form of roof shields are also well known. A particularly useful type of known drive shield is the so-called knife-shield. Such a knife shield has a plurality of elongate planks (or knives) supported side-by-side on a frame.

The knives can be advanced, either singly or in groups, relative to the frame by means of hydraulic rams. When all the knives have been advanced the frame is advanced in a follow-up sequence by the rams. In this way, the entire drive shield is incrementally advanced. It is also known to make roof shields in this manner and to provide the frame members which carry the knives with means for bracing the knives outwardly so as to grip the tunnel walls.

For driving tunnels in hard rock or stone, a drive shield is known which consists of a rigid roof shield which is movable by rollers on the floor of the tunnel. The front of this type of shield is provided with a multi-part protector head for holding up the tunnel roof in the working zone, and the rear of the shield is provided with a tail extension which protects the region in which the permanent tunnel lining is erected.

With this type of drive shield, the actual roof shield has a cross-section which is considerably smaller than that of the tunnel being excavated.

It is, therefore, not possible to hold the rbdf shield firmly against the roof and walls of the tunnel. Moreover, as the tail extension is bent upwardly with respect to the main part of the roof shield, there is a risk that the advance of the shield will be blocked by fallen rocks on the roof shield. Another disadvantage is that the rams used for advancing the shield abut against the permanent tunnel lining and, as there is no firm connection between this lining and the tunnel walls, a firm abutment is not guaranteed. A further disadvantage is that the advance rams have to be individually repositioned each time the shield is advanced.

The aim of the invention is to construct a drive shield for driving tunnels in hard rock, which drive shield will reliably hold up the tunnel roof and walls in the region of the working face, and which will largely eliminate the risk of jamming during shield advance. At the same time, the shield is to be of robust construction and designed so as to leave the maximum free working space in its interior.

The present invention provides a drive shield for use in driving tunnels, the drive shield comprising a roof shield, a pair of support devices for supporting the roof shield, a follow-up unit, and means for advancing the roof shield relative to the follow-up unit, the follow-up unit being provided with bracing units for bracing the follow-up unit against the tunnel walls, the advance means acting between the support devices and the follow-up unit, and the support devices being arranged to raise and lower the roof shield, wherein the support devices are offset laterally, one on either side, with respect to the central longitudinal plane of the roof shield.

With this drive shield, it is possible to adjust the position of the roof shield, using the adjustable support devices, so that it firmly supports the roof and upper walls of the tunnel.

Moreover, the roof shield can be slightly lowered for the purpose of advancing the drive shield.

This permits the roof shield to be advanced without being subjected to any appreciable load.

Advantageously, the support devices are positioned symmetrically with respect to the central longitudinal plane of the roof shield, a respective hydraulic advance ram acting between the follow-up unit and each support device, the two hydraulic advance rams constituting the advance means, and preferably each support device is positioned adjacent to a respective side wall of the tunnel. As the follow-up unit is capable of being braced against the tunnel walls, it forms a firm abutment for the hydraulic advance rams during the advance of the roof shield and its associated support devices.

When the roof shield and support devices have been advanced, the roof shield can be raised so as to be braced firmly against the tunnel roof.

The follow-up unit can then be advanced in a follow-up sequence once the bracing against the tunnel walls is released. Thus, the roof shield/support devices and the follow-up unit can be advanced alternately in a step-by-step fashion. To ensure hermetic sealing for the interior of the drive shield, in the region between the roof shield and the follow-up unit, the roof shield and the follow-up unit overlap one another by a distance which is greater than the working stroke of the advance means.

Each support device may comprise a beam pivotably connected to the roof shield and to a floor sill, and a hydraulic prop acting on the beam. Moreover, the hydraulic prop of each support device may be pivotably connected to the corresponding beam and floor sill, with this arrangement, the applied surface load of the roof shield can be transmitted via the floor sills and distributed over a large area of the tunnel floor. Preferably, each hydraulic prop is provided with a pressure-relief valve so that the roof shield can give way under excess pressure exerted thereon by the overlying strata.

Advantageously, each floor sill extends from a point situated forwardly of the connection between its beam and the roof shield, to a point situated within the follow-up unit. This ensures that the roof shield is supported in a stable manner.

As the beams of the support devices each pivot in a generally vertical plane, it is possible to employ short-stroke hydraulic props. It is also of advantage for the beam of each support device to be connected to the roof shield approximately at the height of the centre of gravity of the roof shield, thus preventing slanting, tilting or warping of the roof shield.

It is also desirable for the beams to be connected to the roof shield approximately midway along the length of the roof shield. It is possible for these connection points to be staggered slightly with respect to the front end of the roof shield. In either case, however, the drive shield is such that the advance forces are conducted satisfactorily into the roof shield structure and for the roof to be adequately supported in the vicinity of the working face.

Preferably, the roof shield is provided with a plurality of elongate planks which can be extended forwardly by means of respective hyhydraulic rams.

Advantageously, the bracing units are hydraulic bracing units which can be expanded to anchor the follow-up unit against the tunnel walls, two bracing units being provided at the base of the follow-up unit and one bracing unit being provided in its roof.

The follow-up unit may also constitute a tail extension for the roof shield, under which tail extension the permanent tunnel lining can be erected. In this case, the follow-up unit may be provided with apertures through which can be inserted sealing elements for the tunnel lining. Preferably, the follow-up unit comprises a non-deformable box-girder framework and said tail extension.

A drive shield constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a part-sectional side elevation of the drive shield, and Figure 2 is to the right of the central chaindotted line, a cross-section takes on the line II-II of Figure 1 and, on the left of said line an end elevation.

Referring to the drawings, the drive shield has a double-walled roof shield 10 internally reinforced by webs 11 to form hollow boxlike girders 12. The roof shield 10 is archshaped in accordance with the desired crosssection of the tunnel (roadway) being excavated In each of the individual girders 12 is telescopically mounted an elongated plank (or knife) 13. Each knife 13 is provided with a hydraulic advance ram 14 which also rests within the corresponding girder 12. The piston rod 15 of each ram 14 is pivotably connected at 16 to the roof shield 10. Thus, by extending the rams 14, either singly or in groups, the knives 13 can be advanced in the direction V towards the face to be worked. Similarly, by retracting the rams 14, the knives can be withdrawn into their girders 12.

Side plates 18 are connected to the bottom sides of the roof shield so as to provide support for the tunnel walls right down to the tunnel floor.

The roof shield 10 is supported by means of a pair of indentical support devices 20, the devices 20 being positioned symmetrically with respect to the central longitudinal plane of the roof shield. Moreover, each support device 20 is situated adjacent to one of the tunnel side walls so that a wide central working space is left within the drive shields. Each support device 20 has a beam 21, a hydraulic prop 22 and a floor sill 23. The rear end of each floor sill 23 is provided with a bracket 24 to the bifurcated end piece 25 of which is pivotably mounted the lower end of the associated beam 21. The upper end of each beam 21 is pivotably connected at 27 to a bracket 28 fastened to the roof shield 10. Each hydraulic prop 22 is pivotably mounted at 29 to its floor sill 23 and is pivotably connected by means of a head joint 30 to its beam 21. The axes of the pivots 26, 27, 29 and 30 are parallel to one another, horizontal and perpendicular to the direction of advance V. The roof shield 10 can, thus, be raised and lowered by extending and retracting the hydraulic props 22. Consequently, the roof shield 10 can be pressed firmly against the tunnel roof to provide adequate support during excavation, and can be lowered to reduce its loading during advance to a new working position. Each hydraulic prop 22 is provided with a pressure-relief valve (not shown) for limiting the pressure to be absorbed by that prop and thus by the roof shield 10.

As can be seen from Figure 1-, each of the floor sills 23 extends from a point forward of the pivotable connection 27 to a point within a follow-up unit 31 which is positioned immediately to the rear of the roof shield 10. This ensures that the roof shield 10 is supported in a stable manner. The pivotable connections 27 are situated approximately midway along the length of the roof shield 10 and at approximately the level of the centre of gravity of the roof shield. This ensures that the roof shield 10 is securely held and supported by the floor sills 23 and so prevents slanting, tilting or warping of the roof shield.

Each support device 20 is provided with a double-acting, hydraulic advance ram 32, the follow-up unit 31 providing the abutment for the two advance rams. The piston rods of the rams 32 are connected by pivotable joints 33 with their respective floor sills 23, and by pivotable joints 34 with the follow-up unit. The two rams 32 are protected by box-shaped lateral extensions 35 of the floor sills 23 (see Figure 2).

The follow-up unit 31 is constituted by a framework 36 made of box-like girders, and a shield tail extension (or cover) 37. The shield tail extension is made of sheet metal and is connected to the framework 36. The roof shield 10, the framework 36 and the shield tail extension 37 all have the same curved profile.

The front part of the framework 36 is provided with a forwardly extending plate 38 which extends into a rear box-shaped portion 39 of the roof shield 10 by a distance which is greater than the working stroke of the advance rams 32. Thus, when the roof shield 10 is advanced relative to the follow-up unit 31, no gap is left therebetween so that the tunnel roof is reliably supported in this region during the advance movement.

In order to anchor the follow-up unit 31 against the tunnel walls for providing a firm abutment during the advance of the roof shield 10, its framework 36 is provided with hydraulic bracing units 40 and 41. A single bracing unit 40 is provided at the top of the framework 36, and two units 41 are provided at its base. Each of the units 40 and 41 occupies a protected position within an appropriate box-shaped compartment of the framework 36, and is provided with a shoe 42 for pressing against the tunnel floor or roof.

The drive shield described above is advanced in the following manner. Firstly, the knives 13 are advanced, either singly or in groups, by their advance rams 14. The advance of the knives 13 secures the tunnel cross-section immediately adjacent to the work face. As soon as all the knives 13 have been advanced, the roof shield 10 can be advanced, the knives 13 simultaneously being telescoped back into their girders 12. For this purpose, the advance rams 32 are extended. During the advance of the roof shield 10, the hydraulic props 22 are relaxed so that the roof shield is wholly or partially relieved of its load. During this advance, the follow-up unit 31 is firmly anchored to the tunnel walls by means of the bracing units 40 and 41. After advance of the roof shield 10, it is braced against the tunnel roof by extending the hydraulic props 22.The bracing units 40 and 41 can then be relaxed and the follow-up unit advanced by retracting the advance rams 32. After its advance, the follow-up unit 31 is again anchored to the tunnel walls by means of its bracing units 40 and 41.

In order to provide a permanent tunnel lining, curved lining sections 43 are provided, these being erected as the tunnel is advanced in a protected position within the tail extension 37 of the follow-up unit 31. During this process, reinforcing elements 44, such as plates or bars, are positioned between adjacent lining sections 43. For this purpose, the tail extension 37 is provided with a central reinforcement web 45 which has slits 46 through which the reinforcing elements 44 are introduced from the roof shield side. The elements 44 are then slid into the space between the inner wall of the tail extension 37 and the outer periphery of the last lining section 43 to be laid. As soon as the tail extension 37 has been moved forward, together with the roof shield 10, a further step, the next lining section 43 is positioned underneath these last introduced reinforcing elements 44.Obviously, the slits 46 are so positioned with respect to the lining elements 43 that the reinforcing elements 44 can be moved without any difficulty from the interior of the shield into their installation position.

WHAT WE CLAIM IS: 1. A drive shield for use in driving tunnels, the drive shield comprising a roof shield, a pair of support devices for supporting the roof shield, a follow-up unit, and means for advancing the roof shield relative to the follow-up unit, the follow-up unit being provided with bracing units for bracing the follow-up unit against the tunnel walls, the advance means acting between the support devices and the follow-up unit, and the support devices being arranged to raise and lower the roof shield, wherein the support devices are offset totally, one or either side, with respect to the central longitudinal plan of the roof shield.

2. A drive shield as claimed in Claim 1, wherein the support devices are positioned symmetrically with respect to the central longitudinal plane of the roof shield, a respec

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the hydraulic props 22. Consequently, the roof shield 10 can be pressed firmly against the tunnel roof to provide adequate support during excavation, and can be lowered to reduce its loading during advance to a new working position. Each hydraulic prop 22 is provided with a pressure-relief valve (not shown) for limiting the pressure to be absorbed by that prop and thus by the roof shield 10. As can be seen from Figure 1-, each of the floor sills 23 extends from a point forward of the pivotable connection 27 to a point within a follow-up unit 31 which is positioned immediately to the rear of the roof shield 10. This ensures that the roof shield 10 is supported in a stable manner. The pivotable connections 27 are situated approximately midway along the length of the roof shield 10 and at approximately the level of the centre of gravity of the roof shield. This ensures that the roof shield 10 is securely held and supported by the floor sills 23 and so prevents slanting, tilting or warping of the roof shield. Each support device 20 is provided with a double-acting, hydraulic advance ram 32, the follow-up unit 31 providing the abutment for the two advance rams. The piston rods of the rams 32 are connected by pivotable joints 33 with their respective floor sills 23, and by pivotable joints 34 with the follow-up unit. The two rams 32 are protected by box-shaped lateral extensions 35 of the floor sills 23 (see Figure 2). The follow-up unit 31 is constituted by a framework 36 made of box-like girders, and a shield tail extension (or cover) 37. The shield tail extension is made of sheet metal and is connected to the framework 36. The roof shield 10, the framework 36 and the shield tail extension 37 all have the same curved profile. The front part of the framework 36 is provided with a forwardly extending plate 38 which extends into a rear box-shaped portion 39 of the roof shield 10 by a distance which is greater than the working stroke of the advance rams 32. Thus, when the roof shield 10 is advanced relative to the follow-up unit 31, no gap is left therebetween so that the tunnel roof is reliably supported in this region during the advance movement. In order to anchor the follow-up unit 31 against the tunnel walls for providing a firm abutment during the advance of the roof shield 10, its framework 36 is provided with hydraulic bracing units 40 and 41. A single bracing unit 40 is provided at the top of the framework 36, and two units 41 are provided at its base. Each of the units 40 and 41 occupies a protected position within an appropriate box-shaped compartment of the framework 36, and is provided with a shoe 42 for pressing against the tunnel floor or roof. The drive shield described above is advanced in the following manner. Firstly, the knives 13 are advanced, either singly or in groups, by their advance rams 14. The advance of the knives 13 secures the tunnel cross-section immediately adjacent to the work face. As soon as all the knives 13 have been advanced, the roof shield 10 can be advanced, the knives 13 simultaneously being telescoped back into their girders 12. For this purpose, the advance rams 32 are extended. During the advance of the roof shield 10, the hydraulic props 22 are relaxed so that the roof shield is wholly or partially relieved of its load. During this advance, the follow-up unit 31 is firmly anchored to the tunnel walls by means of the bracing units 40 and 41. After advance of the roof shield 10, it is braced against the tunnel roof by extending the hydraulic props 22.The bracing units 40 and 41 can then be relaxed and the follow-up unit advanced by retracting the advance rams 32. After its advance, the follow-up unit 31 is again anchored to the tunnel walls by means of its bracing units 40 and 41. In order to provide a permanent tunnel lining, curved lining sections 43 are provided, these being erected as the tunnel is advanced in a protected position within the tail extension 37 of the follow-up unit 31. During this process, reinforcing elements 44, such as plates or bars, are positioned between adjacent lining sections 43. For this purpose, the tail extension 37 is provided with a central reinforcement web 45 which has slits 46 through which the reinforcing elements 44 are introduced from the roof shield side. The elements 44 are then slid into the space between the inner wall of the tail extension 37 and the outer periphery of the last lining section 43 to be laid. As soon as the tail extension 37 has been moved forward, together with the roof shield 10, a further step, the next lining section 43 is positioned underneath these last introduced reinforcing elements 44.Obviously, the slits 46 are so positioned with respect to the lining elements 43 that the reinforcing elements 44 can be moved without any difficulty from the interior of the shield into their installation position. WHAT WE CLAIM IS:

1. A drive shield for use in driving tunnels, the drive shield comprising a roof shield, a pair of support devices for supporting the roof shield, a follow-up unit, and means for advancing the roof shield relative to the follow-up unit, the follow-up unit being provided with bracing units for bracing the follow-up unit against the tunnel walls, the advance means acting between the support devices and the follow-up unit, and the support devices being arranged to raise and lower the roof shield, wherein the support devices are offset totally, one or either side, with respect to the central longitudinal plan of the roof shield.

tive hydraulic advance ram acting between the follow-up unit and each support device, the two hydraulic advance rams constituting the advance means.

3. A drive shield as claimed in Claim 2, wherein each support device is positioned adjacent to a respective side wall of the tunnel.

4. A drive shield as claimed in Claim 2 or Claim 3, wherein each support device comprises a beam pivotably connected to the roof shield and to a floor sill, and a hydraulic prop acting on the beam.

5. A drive shield as claimed in Claim 4, wherein the hydraulic prop of each support device is pivotably connected to the corresponding beam and floor sill.

6. A drive shield as claimed in Claim 4 or Claim 5, wherein each hydraulic prop is provided with a pressure-relief valve.

7. A drive shield as claimed in any one of Claims 4 to 6, wherein the beam of each support device is connected to the roof shield approximately at the height of the centre of gravity of the roof shield.

8. A drive shield as claimed in any one of Claims 4 to 7, wherein the beams are connected to the roof shield approximately midway along the length of the roof shield.

9. A drive shield as claimed in any one of Claims 4 to 8, wherein each floor still extends from a point situated forwardly of the connection between its beam and the roof shield, to a point situated within the follow-up unit.

10. A drive shield as claimed in any one of Claims 1 to 9, wherein the roof shield if provided with a plurality of elongate planks which can be extended forwardly by means of respective hydraulic rams.

11. A drive shield as claimed in any one of Claims 1 to 10, wherein the bracing units are hydraulic bracing units which can be expanded to anchor the follow-up unit against the tunnel walls.

12. A drive shield as claimed in Claim 11, wherein two bracing units are provided at the base of the follow-up unit and one bracing unit is provided in its roof.

13. A drive shield as claimed in any one of Claims 1 to 12, wherein the follow-up unit also constitutes a tail extension for the roof shield, under which tail extension the permanent tunnel lining can be erected.

14. A drive shield as claimed in Claim 13, wherein the follow-up unit is provided with apertures through which can be inserted sealing elements for the tunnel lining.

15. A drive shield as claimed in Claim 13 or Claim 14, wherein the follow-up unit comprises a non-deformable box-girder framework and said tail extension.

16. A drive shield as claimed in any one of Claims 1 to 15, wherein the roof shield and the follow-up unit overlap one another by a distance which is greater than the working stroke of the advance means.

17. A drive shield substantially as hereinbefore described with reference to; and as illustrated by, the accompanying drawings.