AU2391799A - Reinforcing structure for a support pillar - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): INDUSTRIAL NETTING AND MINING PRODUCTS (PROPRIETARY)

LIMITED

Invention Title: REINFORCING STRUCTURE FOR A SUPPORT PILLAR.

r r The following statement is a full description of this invention, including the best method of performing it known to me/us: REINFORCING STRUCTURE FOR A SUPPORT PILLAR BACKGROUND OF THE INVENTION This invention is concerned generally with the provision of support in an underground excavation, between a hanging wall and a foot wall, and is particularly concerned with a reinforcing structure for use in a support pillar.

It is known to construct a support pillar between a hanging wall and a foot wall by placing a settable material into a bag which is suitable braced by a "reinforcing arrangement. The provision of the reinforcement can be problematic for it is desirable to have a compact, easily transportable reinforcing arrangement taking into account the difficult conditions which are encountered underground.

SUMMARY OF THE INVENTION The invention provides a reinforcing structure for a support pillar which includes a tubular member which is formed from diamond mesh orientated so that the member is collapsible in its axial direction with strands of the mesh nesting one in the other, and a plurality of containment rings which are fixed to the tubular member at locations which are spaced from one another in the said axial P.18573/bjt direction.

The tubular member may be formed from a panel of metallic diamond mesh which is shaped into tubular form and wherein opposed ends of each strand of the mesh are welded together so that the tubular form is retained.

The containment rings may be positioned on an inner side of the tubular member but preferably are positioned on an outer side of the tubular member.

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Each ring may be formed from an elongate metallic member such as round bar 15 or flat bar and opposed ends of the elongate member may be welded to each other to form a closed ring.

:i Each ring may be attached to the diamond mesh using suitable ties.

.i In a preferred arrangement of the invention two of the containment rings are located respectively at what, in use, are opposed upper and lower ends of the tubular member.

A flexible bag may be located inside the tubular member. The bag may include an inlet through which a settable material can be introduced into the bag.

P.18573/bjt The bag may be water permeable and may be made from a woven polypropylene or similar material which allows drainage of water from the bag whilst retaining solid or particulate material inside the bag.

The invention also provides a support pillar which includes a reinforcing structure of the aforementioned kind and a load bearing material which fills, and 9* .*In order to construct a support pillar the reinforcing structure must be supported at least for the period during which a load bearing material is introduced into the 0 0 15 bag and while the load bearing material is setting. Preferably the reinforcing structure is supported from an overhead support. According to this aspect of the invention there is provided a method of forming a support pillar between a foot wall and a hanging wall which includes the steps of locating a flexible bag inside a reinforcing structure of the aforementioned kind, securing the bag at least to the containment ring at the said upper end of the tubular member, suspending the reinforcing structure and the bag from the hanging wall with the lower end of the tubular member and a lower end of the bag on the foot wall, filling the bag with a settable load bearing material, and allowing the material to set.

The load bearing material is introduced into the bag in a fluent form and may be of any appropriate type which is known in the art e.g. a slimes slurry or a cementitious material.

BRIFF nF:.qrplr)Tlr)KI rEIFLE p A )F A INQS The invention is further described by way of example with reference to the accompanying drawings in which- Figure 1 is a side view of a support pillar which is constructed using a reinforcing structure according to the invention, Figure 2 illustrates a portion of a tubular diamond mesh member used in the reinforcing structure of the support pillar, and o: 15 Figure 3 illustrates the manner in which the tubular diamond mesh member may be collapsed.

'FER RED EMBOUIMENT Figure 1 of the accompanying drawings illustrates a support pillar 10 according to the invention which is located in an underground excavation 12 and which is positioned between opposing surfaces of a hanging wall 14 and a foot wall 16.

The support pillar includes on its outer side a reinforcing structure 18 which is made up of a bag 20, a tubular diamond mesh member 22 and a number of containment rings 24, and a load bearing material 26 which fills the bag P-18573/bit f o 2 o* 20 The bag 20 is made from woven polypropylene or a similar water permeable material which is capable of allowing water to drain from the bag whilst retaining particulate material inside the bag. At its upper end the bag has an inlet 28 through which material can be introduced into the bag.

The tubular diamond mesh member 22 is made from metallic mesh 30 which is similar to material used for fencing. Figure 2 is an enlarged side view of a portion of the mesh 30. The mesh consists of zig-zag strands 32A, 32B, 32C etc which are threaded one into the other to form a chain-link structure. A panel of the mesh 30 is precut to appropriate dimensions and then folded into a tubular form. Opposing ends of each strand 32 are positioned so that they come into contact with each other and the ends are welded to each other at locations 34 to ensure that the tubular form is retained.

As is evident from Figure 2 each strand 32 extends in zig-zag form in a general horizontal sense. This enables the mesh 30 to be collapsed in a vertical direction which corresponds to the axial direction of the structure 18. Each strand can move downwardly, relatively to its adjacent underlying strand, to take up a nested configuration of the kind shown in Figure 3.

Each containment ring 24 is formed from a length of round or flat bar which is bent into a circular form of appropriate diameter and adjacent opposed ends of P.18573/bjt the round or flat bars are fixed to each other by means of welds 36 to form closed rings. Each ring is attached to an outer side of the tubular diamond mesh member 22 by means of suitable wire ties 38.

Due to the nesting capability of the strands 32, as shown in Figure 3, the structure 18 is capable of bcing collapsed ill the axial sense,-toqether with the rings 24, into a compact arrangement which lends itself to efficient space *utilisation for storage purposes and which may easily be transported and installed in an underground situation.

:15 The structure 18 has a containment ring 24A at what, in use, is a lower end of the pillar and a ring 24B at what, in use, is an upper end of the pillar. The bag is fixed to the upper ring 24B using suitable ties 38A.

In order to construct the pillar a number of roof bolts 40 are first fixed at appropriate locations to the hanging wall 14 using conventional roof bolting techniques. Thereafter the structure 18 and the bag 20 are suspended from the roof bolts using suitable ties 42. The lower ring 24A and a lower end of the bag rest on the foot wall 16. The material 26, in fluent form, is then introduced into the bag through the inlet 28. Water in the fluent material can drain through the permeable fabric from which the bag is made and the particulate material is retained inside the bag and can therefore set to form the load bearing support P.18573/bt pillar 10 which extends between the foot wall and the hanging wall.

In one example of the invention the reinforcing structure 18 included nine of the containment rings. The rings were positioned slightly closer to each other towards a lower end of the pillar and were further apart towards an upper end of the pillar. The pillar had a length of approximately 2,2 metres. The ring 24A woo made from rou l l d bl wit a ldameter ot 12mm while the ring 24B was made from round bar with a diameter of 10mm. The intermediate rings were made from flat bar with dimensions 25 x *o 15 Referring to Figure 2 the size of each aperture 50 in the diamond mesh was approximately 100 x 100mm. The diameter of the wire used in the mesh i.e. the diameter of each strand 32 was approximately 4mm.

The aforegoing dimensions have been given merely by way of non-limiting -example. Within reason the support pillar can be made of any appropriate diameter and length.

An important aspect of the invention is that the reinforcing structure 18 can be constructed to provide substantial reinforcement for the bag 20. Thus it is possible to increase the strength of the reinforcing structure by reducing the aperture size of the mesh and by increasing the diameter of each strand 32. The rI 0S.0T/LJL 3 number and the dimensions of each containment ring can also be increased. On the other hand due to the horizontal orientation of the strands 32 the reinforcing structure retains its collapsible characteristic which, as has been noted, lends itself to storage, transport and ease of erection.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

P.18573/bjt

Claims (9)

1. A reinforcing structure for a support pillar which includes a tubular member which is formed from diamond mesh orientated so that the member is collapsible in its axial direction with strands of the mesh nesting one in the other, and a plurality of containment rings which are fixed to the tubular member at locations which are spaced from one another in the said axial direction.

2. A structure according to claim 1 wherein the tubular member is formed from a panel of metallic diamond mesh which is shaped into tubular form 15 and wherein opposed ends of each strand of the mesh are welded together so that the tubular form is retained.

3. A structure according to claim 1 or 2 wherein the rings are positioned on an outer side of the tubular member.

4. A structure according to any one of claims 1 to 3 wherein each ring is formed from an elongate metallic member opposed ends of which are welded to each other.

5. A structure according to any one of claims 1 to 4 wherein two of the containment rings are located respectively at what, in use, are opposed upper P. 1 8573/bjt and lower ends of the tubular members.

6. A structure according to any one of claims 1 to 5 which includes a flexible bag which is located inside the tubular member and which includes an inlet through which a settable material can be introduced into the bag.

7. A support pillar which includes a reinforcing structure according to claim 6 and a load bearing material which fills, and which has set inside, the bag.

8. A method of forming a support pillar between a foot wall and a hanging wall which includes the steps of locating a flexible bag inside a reinforcing structure according to claim 5, securing the bag at least to the containment ring at the said upper end of the tubular member, suspending the reinforcing structure and the bag from the hanging wall with the lower end of the tubular member and a lower end of the bag on the foot wall, filling the bag with a settable load bearing material, and allowing the material to set.

9. A reinforcing structure for a support pillar substantially as hereinbefore described with reference to the accompanying drawings. Dated this 23rd day of April 1999 INDUSTRIAL NETTING AND MINING PRODUCTS (PROPRIETARY) LIMITED By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia