WO2010148421A1

WO2010148421A1 - Grout plug

Info

Publication number: WO2010148421A1
Application number: PCT/AU2009/000823
Authority: WO
Inventors: Ian Mckay
Original assignee: Mortlach Holdings Pty Ltd
Priority date: 2009-06-26
Filing date: 2009-06-26
Publication date: 2010-12-29
Also published as: AU2009348881A1

Abstract

A grout plug (40) comprises a body (42) provided with a (stop 44) configured to project into and form a substantial seal in a longitudinal slot (22) of a tube (20). A ring (58) is provided about the body (42) adjacent a trailing end of the stop (44) and forms a substantial seal against an inner circumferential surface of the tube (20). The plug (40) is retained within the tube (20) by action of a flap (80) that is bent backwards over itself when the plug (40) is inserted into the tube (20) to effectively wedge the plug (40) in a tube (20). A passage (62) with one way valve (70) allows grout to be injected into the tube (29) and prevents a back flow of the grout through the passage (62). A passage (74) enables air or other gases within the tube (20) or hole (12) in which the tube (20) resides to escape while grout is being injected.

Description

Gr out Plug

Field of the Invention:

The present invention relates to a grout plug.

Background of the Invention

Friction rock stabilizers (herein after referred to in general as "rock stabilizers" ) are used in mining to stabilize the back of an excavated tunnel, drive or drift (hereinafter referred to in general as "tunnel"). One type of rock stabilizer known as a SPLIT SET rock stabilizer manufactured by International Rollforms, Inc. comprises a steel tube provided with a longitudinal slot extending for the full length of the tube. A distal end of the tube is tapered a proximal end of a tube provided with a circumferential ring flange. The ring flange engages a plate through which the tube passes .

In order to stabilize the ground, holes are drilled into the back of the tunnel . The holes are formed with a diameter slightly less than the outer diameter of the tube. The tube is inserted into the hole with the distal (ie narrow) end first to a position where the ring flange engages a plate and the plate is held against the back of the tunnel. Grout is injected into the tube and corresponding hole.

Embodiments of the present invention may provide a mechanism for minimizing the back flow of grout from tubes such as but not limited to those incorporated in rock stabilizers .

Summary of the Invention

One aspect of the invention provides a grout plug for a tube having a longitudinal slot, the grout plug comprising: a body for insertion into the tube, the body provided with a stop configured to project into the longitudinal slot of the tube.

The stop may form a substantial fluid seal in the longitudinal slot.

The stop may be configured to have a width that increases in a radial direction away from the body.

The stop may be formed with recessed side walls.

The stop may be formed of a resilient material.

The stop may have a minimum width that is greater than a width of the longitudinal slot.

The stop may have a leading end that narrows in a direction of insertion of the plug into the tube.

The stop may extend in an axial direction of the body.

The body may comprise an outer circumferential surface and the stop is raised relative to the outer circumferential surface .

The grout plug may comprise a circumferential ring adjacent a trailing end of the stop.

The circumferential ring may engage an inner circumferential surface of the tube.

The ring may form a substantial seal against the inner circumferential surface of the tube. The ring may be made of a resilient material.

The grout plug may comprise a wedging mechanism supported on the body at a location trailing the stop relative to a direction of insertion of the stop into the tube, the wedging mechanism configured to wedge the body in the tube .

The wedging mechanism may extend outwardly of the body in a direction toward the stop.

The wedging mechanism may comprise at least one flap the or each flap having one end coupled with the body and an opposite free end spaced from the body.

The wedging mechanism may comprise a flap extending circumferentially about the body.

The or each flap may extend at an acute included angle relative to a longitudinal axis of the body.

The acute included angle may be between 20° and 40°.

The body may be provided with a first passage enabling the flow of fluid into the tube.

The first passage may be provided with a one way valve arranged to substantially prevent a back flow of fluid out of the tube and through the first passage.

The body may comprise a gas bleed passage enabling a flow of gas out of the tube through the body.

The grout plug may comprise an extension demountably engageable with the body and provided with a second stop configured to project into the longitudinal slot of the tube. - A -

The second stop may form a substantial fluid seal in the longitudinal slot..

The second stop may be configured to have a width that increases in radial direction away from the body.

The second stop may be formed with recessed side walls,

The second stop may be formed of a resilient material.

The second stop may have a minimum width which is greater than a width of the longitudinal slot.

The second stop may have a leading end that narrows in a direction of insertion of the plug into the tube.

The second stop may extend in an axial direction of the body.

The extension may be provided with an axial bore providing fluid communication between the body and the tube.

The extension may comprise a circumferential ring adjacent a trailing end of the second stop.

The circumferential ring of the extension may engage an inner circumferential surface of the tube.

The ring of the extension may form a substantial seal against the inner circumferential surface of the tube.

The ring of the extension may be made of a resilient material .

Brief Description of the Drawings An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a plan view of an embodiment of a grout plug in accordance with the present invention;

Figure 2 is a sectional elevation of the plug shown in Figure 1 ;

Figure 3 is a view of a first end of the plug shown in Figures 1 and 2 ;

Figure 4 is a view of an opposite end of the plug shown in Figures 1 and 2;

Figure 5 is a view of section AA of the plug shown in Figure 2 ;

Figure 6 is a plan view of a first sleeve incorporated in the plug;

Figure 7 is a plan view of a second sleeve incorporated in the plug;

Figure 8 is a plan view of an extension which may be incorporated in the plug;

Figure 9 is a sectional view of the extension shown in Figure 8;

Figure 10 is a view of a first end of the extension shown in Figures 8 and 9 ;

Figure 11 is a view of an opposite end of the extension shown in Figures 8 and 9 ; Figure 12 is a view of section AA of the extension shown in Figure 9 ;

Figure 13 is a sectional elevation of an extended plug comprising the plug shown in Figures 1 and 2 coupled with the extension shown in Figures 8 and 9; and

Figure 14 is a schematic representation of a rock stabilizer inserted into a hole formed in a back of a tunnel .

Detailed Description of Preferred Embodiment

To provide context to the described embodiments of the present invention references made to Figure 14 which illustrates a rock stabilizer 10 inserted into a hole 12 formed in a body rock 14 in which a tunnel 16 is excavated. A free face of the rock 14 forms a surface 18 of the tunnel 16. Split set 10 comprises a steel tube 20 provided with a longitudinal slot 22 that extends between a tapered distal end 24 and a proximal end 26 of the tube 20. A ring flange 28 is formed about the tube 20 near but in board of the proximal end 26. The ring flange 28 engages a hole formed in a rectangular plate 30 through which the tube 20 passes. The plate 30 is clamped against the back 18 by the ring flange 28. The plate 30 holds a wire mesh 31 against the back 18 to provide protection to workers and equipment from rock falls. The mesh 31 is held by multiple rock stabilizer 10 against the back 18. The hole 18 is formed with an inner diameter less than the outer diameter of the tube 20 (although for the sake of clarity in Figure 14, the hole 12 is shown with a larger diameter) . Accordingly, when the tube 20 is inserted into the hole 12 it is compressed radially resulting in a narrowing (but not a closing) of the longitudinal slot 22. The tube 20 has a degree of resilience and accordingly applies a reactive force against the hole 12. This assists in maintaining the tube 20 within the hole 12 and clamping the plate 30 and mesh 31 against the back 18. To stabilize the rock 14, grout is injected into the tube 20 and the hole 12. The grout also limits or reduces corrosion of the tube 20. Depending on the configuration of the surface 18, a proximal length 32 of the slot 22 extends from the hole 12 into the tunnel 16.

As explained below, embodiments of the grout plug 40 provide a mechanism for filling of the tube 20 and hole 12 with grout, while substantially preventing or minimizing the back flow of grout from the split set 10.

With reference to the accompanying drawings and in particular Figures 1-5, the grout plug 40 comprises a body 42 provided with a stop 44 configured to project into the longitudinal slot 22 of the rock stabilizer 10. The stop 44 is configured to form a substantial seal in a slot 22 which assists in preventing a backflow of grout out of the rock stabilizer 10.

In the illustrated embodiment the stop 44 is configured to have a width that increases in the radial direction R away from the body 42. This is illustrated most clearly in Figure 5 which shows the stop 44 with a minimum width Wl adjacent an outer circumferential surface 46 of the body 42 and a maximum width W2 the radial most distant upper surface 52 of the stop 44. The increase in the width is facilitated by recessing sidewalls 48 of the stop 44. Thus the longitudinal edges 50 of the upper surface 52 of stop 44 overhang the circumferential surface 46 of the body 42.

The stop 44 is made of a resilient material with the minimum width Wl of the stop 44 being greater than the transverse width WS of the slot 22. Thus when the plug 40 is inserted into the rock stabilizer 10, the stop 44 is compressed as it enters the slot 22. Further, the stop 44 projects through the slot 22 so that the upper surface 52 of the stop 44 lies substantially adjacent or proud of an outer surface of the tube 20.

To assist in inserting the stop 44 into the slot 22, a leading end 54 of the stop 44 narrows or tapers in a direction D of insertion of the plug 40 into the split set 10. Further, as illustrated in Figure 2, leading end 54 has a ramp-like surface 56 which slopes in a rearward direction referenced to the direction of insertion D from the circumferential surface 46 of the body 42 to the upper surface 22 of the stop 44. Both the narrowing and ramping of the leading end 54 assist in insertion of the stop 44 into the slot 52. The stop 44 also extends in an axial direction of the body 42 so as to occupy a length of the stop 44 when the plug 40 is inserted into the split set 10.

A circumferential ring 58 extends about the body 42 adjacent a trailing end 60 of the stop 44. Ring 58 is configured or dimensioned so that it engages an inner circumferential surface of_. the rock stabilizer 10 when the plug 40 is inserted into the rock stabilizer 10. In order to accomplish this, the ring 58 has a maximum diameter greater than an inner diameter of the tube 20. Further, the ring 58 is made of a resilient material so as to compress against the inside surface of the tube 20 and form a circumferential seal. It will thus be appreciated that when the plug 40 is inserted into the rock stabilizer 10, the stop 44 projects into and forms a seal in the slot 22 while the ring 58 forms a seal against an inner circumferential surface of the rock stabilizer 10. Thus, with reference to Figure 14, provided the stop 44 lies inside the hole 12 when the plug 40 is inserted into the split set 10, the plug 40 will form a seal substantially preventing the backflow of grout through the slot 22 and between the circumference of the tube 20 and the outer circumferential surface 46 of the body 42.

In order to initially inject grout into the rock stabilizer 10 and hole 12, the plug 40 is provided with a first passage 62 which extends from a first end 64 of the plug 40 in an axial direction toward a leading end 66 of the body 42. However, as shown in Figure 2, the passage 62 has a leading end 68 that lies in board of the end 66 of the body 42. A one-way valve 70 comprising resilient flaps 72 is provided in the passage 62 near the leading end 68. A bleed passage 74 is also formed in the body 42, parallel with the passage 62. The bleed 74 is co-terminus with the passage 62.

When the plug 40 is in use, a hose (not shown) is inserted into the passage 62 typically to a location where it pushes the valve 70 open. Grout is injected through the hose to fill the tube 20 and hole 12 with grout. A bleed hose (not shown) is previously inserted into the hole 12 and is of a length so that a distal end of the hose lies adjacent a toe of the hole 12. An opposite end of the hose is pushed into the bleed passage 74. Thus, while grout is being injected into the tube 20 and hole 12, air or other gases within the hole 12 are displaced and flow through the bleed hose and bleed passage 74 into the tunnel 16. As the distal end of the bleed hose is near the toe of the hole 12 there is very little or no backflow of grout into the bleed hose . Any grout that feeds into the bleed hose would typically solidify prior to reaching the bleed passage 74.

In order to maintain a minimum inner diameter of the passages 62 and 74, each is fitted with a respective sleeve 76 and 78 (see Figures 6 and 7) . The sleeves 76 and 78 are made from a relatively incompressible material such as NYLON. In relation to the passage 62, this ensures that the hose used to insert grout into the rock stabilizer 10 / tube 20 can be inserted and withdrawn from the passage 62 once the grouting has been completed. The sleeve 78 maintains a minimum diameter of the passage 74 to allow insertion of the bleed hose.

A wedging mechanism 80 in the form of a flap is formed about the body 42 at a location trailing the stop 44. In this particular embodiment, the flap 80 extends wholly about the circumferential of the body 42 and extends outwardly of the body toward the stop 44. Thus, the flap 80 has a trailing end 82 that is coupled with the body 42 and a free leading end 84 that is spaced from the outer circumferential surface 46 of the body 42. The flap 80 extends at an acute angle included angle θ relative to a longitudinal axis 86 of the plug 40. The acute included angle θ may be between 20°-60°. Leading end 84 provides the flap 80 with a maximum outer diameter which is greater than the inner diameter of the tube 20. Thus when the plug 40 is inserted into the tube 20, the leading end 84 engages the mouth and/or inner circumferential surface of the tube 20 and is pushed backward and outward over itself. This has the effect of wedging the plug 40 in the split set 10. If desired, multiple wedging mechanisms 80 may be provided about the body 42.

The wedging mechanism 80 also acts as a secondary barrier against the back flow of grout in the event of grout by passing the stop 44 and ring 58. In this regard due to the resilient nature of the flap 80 it will partially extend into and thus partially block the slot 22. The blocking effect of the flap 80 in the slot 22 may be enhanced by providing the flap 80 with either (a) two parallel spaced apart axial cuts or slits to form a finger of a width to enable it to project further into the slot 22; or (b) a plurality of parallel axial slits to form multiple narrow fingers a plurality of which project into the slot 22. The slits may typically be formed in portion of the flap 80 in alignment with the stop 44.

The trailing end 64 of the body 42 is formed with a lateral flange 88 which abuts the proximal end 26 of the tube 20 when the plug 40 is inserted into the split set 10.

A void 90 is provided between leading end 66 of the body 42 and the leading end of the passages 62 and 74. The void 90 forms a socket which can receive an extension 92 (see Figures 8-13) that forms an optional component of the plug 40. The extension 92 is provided with a spigot 94 configured to seat in the void 90 and an axial bore 96 which enables grout to flow into the tube 20 and hole 12, as well as enable the bleed hose to feed to the passage 74. The spigot 92 when inserted into the body 42 has a trailing end 98 which is spaced from the leading end 68 of the passage 62 when extension 92 is fully inserted into the body 42. This space enables the bleed hose to fit in the bleed passage 74 as well as unimpeded opening of the valve 70.

The extension 92 is also provided with a stop 44a of an identical shape, configuration and function as the stop 44, and a circumferential ring 58a of identical shape, configuration and function to the ring 58.

Whether or not the extension 92 is used is dependent upon the size of the rock stabilizer 10, and the distance by which the proximal end 26 of the rock stabilizer 10 extends from the free face 18 (ie the distance traversed by proximal length 32 of the slot 22) . In the event that the stop 44 on the body 42 resides only in the proximal length 32 and thus sits outside of the hole 12, then the extension 92 should be used so that the stop 44A engages the slot 22 at a location inside of the hole 12. This will then prevent a leakage of grout to the proximal end 32 and out of the rock stabilizer 10.

Modifications and variations to the described embodiments of the plug 40 as will be apparent to those of ordinary- skill in the art are deemed to be within the scope of the present invention the nature of which is to be determined from the above description.

Claims

The Claims Defining the Invention are as follows:

1. A grout plug for a tube having a longitudinal slot, the grout plug comprising: a body for insertion into the tube, the body provided with a stop configured to project into a longitudinal slot of the tube.

2. The grout plug according to claim 1 wherein the stop forms a substantial fluid seal in the longitudinal slot.

3. The grout plug according to claim 1 or 2 wherein the stop is configured to have a width that increases in a radial direction away from the body.

4. The grout plug according to any one of claims 1-3 wherein the stop is formed with recessed side walls.

5. The grout plug according to claims 1-4 wherein the stop is formed of a resilient material.

6. The grout plug according to any one of claims 1-5 wherein the stop has a minimum width that is greater than a width of the longitudinal slot.

7. The grout plug according to any one of claims 1-6 wherein the stop has a leading end that narrows in a direction of insertion of the plug into the tube.

8. The grout plug according to any one of claims 1-7 wherein the stop extends in an axial direction of the body.

9. The grout plug according to any one of claims 1-8 wherein the body comprises an outer circumferential surface and the stop is raised relative to the outer circumferential surface.

10. The grout plug according to any one of claims 1-9 comprising a circumferential ring adjacent a trailing end of the stop.

11. The grout plug according to claim 10 wherein the circumferential ring engages an inner circumferential surface of the tube.

12. The grout plug according to claim 11 wherein the ring forms a substantial seal against the inner circumferential surface of the tube.

13. The grout plug according to any one of claims 10-12 wherein the ring is made of a resilient material.

14. The grout plug according to any one of claims 1-13 comprising a wedging mechanism supported on the body at a location trailing the stop relative to a direction of insertion of the stop into the tube, the wedging mechanism configured to wedge the body in the tube.

15. The grout plug according to claim 14 wherein the wedging mechanism extends outwardly of the body in a direction toward the stop.

16. The grout plug according to claim 15 wherein the wedging mechanism comprises at least one flap the or each flap having one end coupled with the body and an opposite free end spaced from the body.

17. The grout plug according to claim 15 or 16 wherein the wedging mechanism comprises a flap extending circumferentialIy about the body.

18. The grout plug according to claim 16 or 17 wherein the or each flap extends at an acute included angle relative to a longitudinal axis of the body.

19. The grout plug according to claim 18 wherein the acute included angle is between 20° and 60°.

20. The grout plug according to any one of claims 1-19 wherein the body is provided with a first passage enabling the flow of fluid into the tube.

21. The grout plug according to claim 20 wherein the first passage is provided with a one way valve arranged to substantially prevent a back flow of fluid out of the tube and through the first passage.

22. The grout plug according to any one of claims 1-21 wherein the body comprises a gas bleed passage enabling a flow of gas out of the tube through the body.

23. The grout plug according to any one of claims 1-22 comprising an extension demountably engageable with the body and provided with a second stop configured to project into the longitudinal slot of the tube.

24. The grout plug according to claim 23 wherein the second stop forms a substantial fluid seal in the longitudinal slot.

^■ 25. The grout plug according to claim 23 or 24 wherein the second stop is configured to have a width that increases in radial direction away from the body.

26. The grout plug according to any one of claims 23-25 wherein the second stop is formed with recessed side walls.

27. The grout plug according to any one of claims 23-26 wherein the second stop is formed of a resilient material.

28. The grout plug according to any one of claims 23-27 wherein the second stop has a minimum width which is greater than a width of the longitudinal slot.

29. The grout plug according to any one of claims 23-28 wherein the second stop has a leading end that narrows in a direction of insertion of the plug into the tube.

30. The grout plug according to any one of claims 23-29 wherein the second stop extends in an axial direction of the body.

31. The grout plug according to any one of claims 23-30 wherein the extension is provided with an axial bore providing fluid communication between the body and the tube.

32. The grout plug according to any one of claims 23-31 wherein the extension comprises a circumferential ring adjacent a trailing end of the second stop.

33. The grout plug according to claim 32 wherein the circumferential ring of the extension engages an inner circumferential surface of the tube.

34. A grout plug according to claim 33 wherein the ring of the extension forms a substantial seal against the inner circumferential surface of the tube.

35. A grout plug according to any one of claims 32-34 wherein the ring of the extension is made of a resilient material .

36. The grout plug according to any one of claims 16-35 wherein the flap forms a substantial seal against the inner circumferential surface of the tube.

37. The grout plug according to any one of claims 16 to 36 wherein the flap is made of a resilient material.

38. The grout plug according to any one of claims 16-37 wherein the flap comprises a leading end configured to engage a mouth or the inner circumferential surface of the tube when the plug is inserted in to the tube.

39. The grout plug according to any one of claims 16-38 wherein the flap comprises one or more fingers configured to project in to the slot.