AP984A

AP984A - Pillar bag.

Info

Publication number: AP984A
Application number: APAP/P/1997/000970A
Authority: AP
Inventors: Plessis Joseph Albertus Du
Original assignee: Alnet Pty Limited
Priority date: 1996-07-25
Filing date: 1997-02-24
Publication date: 2001-07-27
Also published as: BR9701201A; AU718182B2; CA2198808A1; US5823718A; RU2173387C2; DE19705713A1; AP9700970A0; AU1482297A

Abstract

A pillar bag which is made from a synthetic fabric which is folded, at vertically spaced intervals, to from a number of sheaths, with each sheath housing a reinforcing ring.

Description

BACKGROUND OF THE INVENTION 5

This invention relates to a pillar bag of the kind used in an underground excavation in order to provide support between a hanging and foot wall. The bag is mounted to suitable supporting structure and is then filled with a cementitious or other settable material which is allowed to harden.

It is desirable with this type of bag to make use of some form of reinforcing to provide hoop strength for the bag. It is also desirable to protect the reinforcing from the effects of blasting which can occur during mining operations.

SUMMARY OF THE INVENTION

The invention provides a pillar bag which is made from a suitable fabric and which includes at least one reinforcing ring which is formed from at least one closed loop of elongate material.

The closed loop may be formed from a flexible material such as a rope wfficFTrriay be spliced onto itself, from a hollow core rope or braid which is inserted into itself, from an elongate steel member, which may for example be round bar or flat bar, closed and secured eg by welding onto itself, or in any other appropriate way.

The closed loop of elongate material may be located in a preformed sheath which is attached to the fabric. In order to protect the loop from the effects of blasting or any other harmful external cause it is desirable to locate the loop, and hence the sheath, inside the bag.

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If however the loop is made from steel or any other material which may resist the effects of blasting then it is possible to attach the sheath to the outside of the bag.

The sheath may be formed from any appropriate fabric or materia, which is 10 attached for example by stitching to the bag.

In a different form of the invention the closed loop of elongate material is enclosed in a sheath which is formed from the fabric from which the bag is made.

.- The sheath may be defined by folding the bag fabric appropriately, locating the loop between two opposed sections of the fold, and stitching or otherwise securing the sections to one another.

With this form of the invention the sheath may be formed inside or outside the bag.

The bag may include a plurality of the loops at spaced intervals from one another along the height of the bag. The number of loops, their spacing, the material

·.. from which they are made and the strength of the loops are determined substantially empirically, through tria, and experiment, according to design requirements.

The invention also provides a pillar bag which is made from a suitable fabric and which includes at least one sheath which is formed by suitably folding the fabric and at least one reinforcing ring located in the sheath.

The sheath may be positioned so that it is inside the bag or outside the bag, in use.

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The bag may include a plurality of the sheaths at spaced intervals from one another with each sheath respectively housing a suitable reinforcing ring.

The reinforcing ring may be flexible and may be made from any suitable material such as nylon or polypropylene or it may be made from a metallic material such as steel in which event it could for example comprise round bar or flat bar.

Depending on the material which is to be placed in the bag the material from which the bag is made could be water pervious, to allow water to drain from the bag, or impervious. In the latter case the bag could be filled with a settable grout, which could include a gelling agent, to reduce water seepage. The bag material may be synthetic eg knitted polyethylene or polypropylene fibre.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of examples with reference to the accompanying drawings in which:

Figure 1 illustrates a reinforcing ring, according to one form of the invention, for use in the pillar bag of the invention;

Figure 2 is a cross-section through the material from which the reinforcing ring 2o of Figure 1 is made;

Figure 3 and 4 respectively illustrate alternative reinforcing rings for use in the pillar bag of the invention;

Figure 5 is a cross-sectional view through a portion of a pillar bag according to one form of the invention;

Figure 6 is a cross-sectional view through a portion of a pillar bag according to another form of the invention;

Figure 7 illustrates a side wall of a pillar bag according to another form of the invention;

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Figure 8 depicts a pillar bag with an optional feature according to the invention; and

Figures 9 and 10 are graphs of load vs displacement measured under test conditions for pillar bags of the kind shown in Figures 5 and 6 respectively.

DESCRIPTION OF PREFERRED EMBODIMENTS

Figure 1 and 2 of the accompanying drawings illustrate a braided polypropylene rope 10 which has a hollow core 12 and which is threaded into itself for a complete loop, as shown in Figure 1. The leading end 14 of the rope is then

Io threaded transversely through the rope. This simple form of construction provides a closed loop of significant strength. In Figure 1 the proportions of the loop have been distorted only for the sake of clarity of illustration for, in practice, the ratio of the diameter of the loop to the diameter of the rope is substantially greater than what is illustrated.

Figure 3 illustrates a different way of making a reinforcing ring 16 wherein a flexible rope 18 is fashionedT into> a closed loop bymeans of a splice 20 at abutting ends of the rope.

a- Figure 4 illustrates a third form of reinforcing ring 22 which consists of a length 24 of steel round bar or flat bar shaped into a ring, with abutting ends welded together at a location 26.

Figure 5 depicts a cross-section through a pillar bag 28 according to a first form of the invention. Before upper and lower ends are fixed to the bag, the fabric of the bag is folded inwardly at a number of locations 30, only one of which is shown in the drawing. In this way two opposing fabric sections 32 and 34 are formed and a reinforcing ring 36 which may be of the kind shown in any one of

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Figures 1, 3 and 4, is placed between the two sections 32 and 34. These sections are then sewed to one another along lines 38 and 40.

In the pillar bag 42 shown in Figure 6 a similar technique is adopted but, in this case, the sheath 44 is formed by folding the bag fabric upwardly to form fold sections 46 and 48. A reinforcing ring 50 is positioned between the folded fabric sections which are then stitched to each other along lines 52 and 54.

Figures 9 and 10 show graphs of load vs displacement for pillar bags 28 and 42 of the kind shown in Figures 5 and 6 respectively. A high initial load bearing io capability of at least 200 tons is rapidly achieved with a relatively small displacement, of the order of 70mm, and thereafter the bags have significant load bearing ratings while yielding up to about 280mm in the former case and 350mm in the latter case.

Figure 7 illustrates a wall 56 of a pillar bag 58 to which is attached, on an inner or outer surface as the case may be, a preformed sheath 60 which contains a

AR/P/ 97/00970 reinforcing ring 62. In this case the sheath 60 is formed by overlapping lengths— of material and the ring 62 is held in position by means of stitching 64. Subsequently, by means of stitching 66, the sheath is attached to the fabric of the bag.

With the arrangement shown in Figure 5 it is possible to use reinforcing rings which are made from relatively soft material such as polypropylene, nylon or the like. When the bag is filled with a slurry, eg a slimes mixture, or a cementitious mixture, the reinforcing rings 36 are embedded in the mixture and consequently are protected from the effects of blasting which can take place in underground conditions and which otherwise could possibly damage the reinforcing rings. The integrity of the bag is therefore largely ensured.

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With the Figure 6 arrangement the reinforcing ring 50 will normally be of steel for it is on an exposed outer side of the bag once the bag has been filled with a cementitious mix. The steel, which could be of round bar or flat bar, is able to withstand the effects of blasting.

With the Figure 7 arrangement the reinforcing ring 62 may be of any of the types shown in Figures 1, 3 and 4 or, in fact, be formed in any appropriate way by means of a length of elongate material which is closed on itself. Again, as has been noted, if the ring 62 is of a relatively soft material it is located inside the bag while, if the ring 62 is made from a material such as steel which can withstand the j

Ί-j effects of blasting, it is possible to position the sheath and hence the ring on the outer side of the bag.

Figure 8 shows a complete filler bag 70 which has a number of reinforcing rings 72 at spaced intervals along its length. The bag has ties 74 fixed to it at appropriate points to facilitate erection of the bag and, more particularly, to tie the bag to supporting structures under adverse, eg sloping, conditions.

Preferably the bag is made from material which is formed with integral reinforcement which extends longitudinally in the vertical direction 76 of the bag, as depicted by means of arrows in Figure 5. Thus the bag is reinforced both in the vertical sense by means of the reinforcement 76, and in a hoop manner by means of the reinforcing rings.

It is to be noted that the number and spacing and strength of the reinforcing rings 30 are largely determined by the particular application in mind.

Claims

1. A pillar bag which is made from a suitable fabric and which includes at least one reinforcing ring which is formed from at least one closed loop of elongate material.

2. A pillar bag according to claim 1 wherein the close loop is selected from the following: a rope which is spliced onto itself; a hollow core rope or braid which is inserted into itself; an elongate steel member which is closed in a loop and secured onto itself.

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3. A pillar bag according to claim 1 or 2 wherein the loop is located in a preformed sheath which is attached to the fabric.

4. A pillar bag according to claim 1 or 2 wherein the loop is 20 enclosed in a sheath which is formed from the fabric.

5. A p.jj_ar k_agto claim 4whereinIhe sheath Tsformeci by folding the fabric, locating the loop between two opposed sections of the fold, and securing the sections to each other.

6. A pillar bag according to claim 3, 4 or 5 wherein the sheath is located on what, in use, is an inner side of the fabric.

7. A pillar bag according to claim 3, 4 or 5 wherein the sheath is 30 located on what, in use, is an outer side of the fabric.

8. A pillar bag according to any one of claims 1 to 7 which includes a plurality of the loops at vertically spaced intervals from one another.

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9. A pillar bag which is made from a suitable fabric and which includes at least one sheath which is formed by suitably folding the fabric and at least one reinforcing ring located in the sheath.

10. A pillar bag according to claim 9 wherein the ring is made from a material selected from the following: a flexible material; a metallic material.

11. A pillar bag according to claim 9 or 10 wherein the sheath is positioned on what, in use, is an inner side of the fabric.

12. - A pillar bag according to claim 9 or 10 wherein the sheath is positioned on what, in use, is an outer side of the fabric.

13. A pillar bag according to any one of claims 9 to 12 which includes a plurality of the sheaths at spaced intervals from one another with each sheath respectively housing a suitable reinforcing ring.

14. A pillar bag which is made from a synthetic fabric which is folded, at vertically spaced intervals, to form a number oh sheaths, with each sheath housing a reinforcing ring.