GB2095308A

GB2095308A - Method and apparatus for consolidating rock strata

Info

Publication number: GB2095308A
Application number: GB8208055A
Authority: GB
Original assignee: Willich F GmbH and Co
Current assignee: Willich F GmbH and Co
Priority date: 1981-03-24
Filing date: 1982-03-19
Publication date: 1982-09-29
Also published as: PL131495B1; PL235607A1; CS204382A3; CS276967B6; FR2502688A1; AU8183282A

Abstract

The rock and coal strata which tend to flake or break out are stuck or nailed to one another in that, simultaneously with the consolidation, anchors or spikes 4 of tubular form are introduced and stuck in the drill hole by means of the consolidating material. The tubular rod consists of material of high strength having an elasticity far above that of steel, and thus is usable especially as anchor in roadways which are heavily stressed at the gallery connection. Possibilities of attachment for high-pressure pumps are produced by suitable ends. A uniform distribution of the consolidating agent in the cavity between rod and drill hole wall is guaranteed by bores formed over the length. A device serving simultaneously as consolidating cartridge, anchor and spike has an interior divided by a partition into two chambers, the chamber walls having apertures closed by the side edges of the partition while the partition carries a mixer head at the upper end and is conducted out of the device at the lower end. <IMAGE>

Description

SPECIFICATION Method and apparatus for consolidating rock strata The invention relates to a method for consolidating rock strata in mining and tunneling in which the consolidating material is injected into the rock under pressure into and/or through prepared drill holes. The invention further relates to a device for consolidating, especially anchoring, rock strata, consisting of a rod which when introduced into the drill hole protrudes therefrom by a predetermined amount.

Roadways and other cavities opened up by blasting work or with roadway driving machines are secured in underground mining and tunneling by rigid or yieldable steei or reinforced concrete supporting or by anchors. Especially working roadways or roadways affected by the effects of working are then frequently subsequently or even simultaneously in driving made adherent and secured by consolidation of the surrounding rock strata. For this purpose a cement solution or a special adhesive synthetic plastics material is forced under pressure through drill holes into the rock. The rock strata thus consolidated can take up the stresses deriving from the winning work better than can the roadways secured exclusively with steel arches or concrete or compositecon crete supporting.Furthermore adhesive cartridges or injection- methods are used in the gallery itself in order to secure the coal face which tends to batter out. For this purpose what are called wood spikes, that is long wooden rods, are also driven into the prepared drill holes and if possible stuck within the drill hole, in order thus to hold fast, that if nail fast, the coal strata.

It is also known to secure working roadways and spaces by means of anchors, in which case the rock strata which tend to flake out are nailed with the aid of the rock anchors to firmer rock.

The anchors furthermore have the effect of holding together the strata arranged between anchor plate and the anchor tip. Various anchoring systems exist, as for example expanding sleeve anchors, adhesion anchors and slide anchors. These anchoring methods have the disadvantage however that they always affect only a tubular or pear-shaped part of the rock around the anchor, so that according to the nature of the rock it can occur that anchored rock strata break into the open cross-section. Inter alia this also applies to adhesion anchors, where especially in the case of fissured rock the adhesive composition frequently does not suffice for adequate adhesion of the anchor with the rock because the adhesive composition flows away into the fissures.

The invention is based upon the problem of producing a method with which the rock zone affected in each case by the operations can be substantially enlarged and appropriately made continuous round about the roadway, and with which the nailing of the coal strata can be optimalised. Moreover suitable devices are to be produced for these purposes.

The problem is solved in accordance with the invention in that simultaneously with the consolidation of the rock, anchors or spikes are introduced and stuck with the consolidating material in the drill hole.

By the simultaneous introduction and adhesion of the anchor or, in the seam consolidating of the spike in the drill hole in any case required for the consolidation, not only can two operations be combined and optimalised, but at the same time it becomes possible to produce a consolidated rock jacket around the roadway, which can no longer break away because it is additionally stabilised by the anchors in the region near the roadway crosssection. The length of the drill holes will here be predetermined, irrespective of the length of the anchor rods, according to the criteria of rock consolidation. As a rule here the length of the anchor rods will be less than the length of the drill holes.Equally when used in the nailing of coal seams, the method according to the invention has advantageous effects because the region influenced by the adhesive or the consolidating material is substanlially enlarged.

Escape of the consolidating material into the roadway cross-section is effectively prevented in that the consolidating material is introduced under reduced pressure into the region of the mouth of the drill hole. Thus at the same time sticking of the anchor over its whole length is possible, so that the rock strata are held together in this region too by means of their connection with the anchor, which is advantageous especially in the case of obliquely applied anchors and spikes.

Simultaneous good consolidation of the rock by adhesion and good attachment of the device to the drill hole wall are achieved in that in accordance with the invention as consolidating material an adhesive composition, foaming or non-foaming, of good adhesion is used, and is forced by sections against and into the rock, starting from the deepest part of the drill hole, considered over the length of drill hole. Thus firstly the strata lying most remote from the roadway cross-section are consolidated, and only then those lying nearer to the roadway, so that not only can undesired escape of the consolidating material into the roadway crosssection be prevented, but at the same time a systematic adhesion and consolidation of the rock strata to the rock regions not yet influenced by the workings can be achieved.The same again applies to use in the seam in spiking, if the regions lying furtherst from the working face are first stuck and only then the seam regions already somewhat loosened by the working are stuck.

For spiking it can here be advantageous for the consolidating material to be charged into cartridges for introduction into the drill hole and then burst with the aid of a tubular spike and distributed in the drill hole and at the same time in the tubular spike itself. As tubular spike there is designated a device consisting of a hollow rod through which the adhesive material is forced in injection and pressed into the rod when cartridges are used.

For the execution of the method a device is proposed which consists of a rod which when introduced into the drill hole protrudes therefrom by a predetermined amount. In accordance with the invention here the rod is made in tubular form.

Such a device can be introduced into the drill hole immediately after its completion, in which case then the consolidating material is forced by a high-pressure pump through the hollow rod into the rock. Naturally the cavity remaining between the periphery of the tube and the drill hole wall in that case becomes filled with the consolidating material which connects the tube and wall with one another. A regular adhesion of the rod over its entire length is ensured thus. Moreover the rod is itself filled with the consolidating material and thus becomes one unit. The rod is here advantageously produced from elastic material of high strength and equipped with a connecting or attaching piece at the end protruding from the drill hole. The rod is connected to the highpressure pump through the connecting or attaching piece without difficulty nor expenditure of time.

Since the rock strata are frequently flaked open in the region close to the excavated cross-section and also close to the drill holes, and thus in the case of injection to the whole depth of the drill hole consolidating material could escape into the free roadway cross-section, it is expedient to equip the rod with one or more sealing collars formed in the lower part, in which collars there are provided bores of small calibre extending parallel with the rod. The desired pressure reduction in the lower region of the device can be achieved in a simple manner by way of the sealing collar or collars.

Instead of the sealing collars, it can also be expedient to form the shell of the tube with annular attenuation in one or more zones, in which case a valve flap seated externally upon the tube shell is arranged above these zones. The valve flap achieves the object that firstly such a pressure builds up in the rod that the elastic material inflates into a bead in the attenuated zones and then rests closely on the wall of the drill hole. However the valve flaps are formed so that when an appropriate pressure is reached or exceeded they bend over and then clear the way for the consolidating material into the interspace between drill hole wall and anchor.

Especially when the device according to the invention is used as spike for the spike attachment of coal strata which tend to run out, it is adavantageous if the shell of the tube has bores in specific zones or in distribution over the entire length, and a quick-acting catch at the lower end emerging from the drill hole. Such a device leads more to adhesion than to injection of the coal or rock, while a rapid connection with the highpressure pump or charging pump can be achieved by way of the quick-acting catch at the protruding end. Flowing of the consolidating material out of the hollow rod is here suppressed in a simple manner in that the quick-acting catch, formed as plug-in fastening with clip, has a troughing corresponding with a ball valve which is arranged above in the rod.

The introduction of the rod for example into the drill holes prepared in the coal is facilitated according to the invention in that the end of the rod arranged in the drill hole can be closed by means of a stopper with rounded cap and insert end, the cap being made to protrude beyond the shell of the tube. In the subsequent filling or introduction of the consolidating material under pressure this stopper is forced away from the rod, so that sufficient filling material can escape from the upper opening of the rod.

For easier arresting of the device within the drill hole downwardly pointing barbs are formed on the shell of the tube. It is also advantageous to arrange the sealing collars and/or the valve flaps at the tip and/or over the length of the rod, forming sections. Near the plug-in end it can also be advantageous, according to use, for the rod to have an internal threading at the roadway end.

Especially for use as spike for consolidating coal strata which tend to run out, an embodiment of the invention is conceived in which within the rod there are arranged one or more mechanically destroyable cartridges filled with consolidating material.

Furthermore the interior of the rod can also be divided, forming two chambers, by a longitudinally displaceably arranged partition guided in the tube, at the end of which facing the rod tip a mixer head is arranged. In the case of such a formation the device at the same time forms the cartridge, which suitably is no longer destroyed but in which rather the adhesive, previously stored in the separate chambers is intermixed and thus brought to reaction through the mixer head by extraction of the partition. Escape of the adhesive from the rod, serving as cartridge, is achieved at the right moment in that the side edges of the partition are made in dovetail form. In the region of the guide the tube shell expediently has apertures which are closable from the chambers by the partition. For this purpose, to seal off the region of the guide, it can be expedient to form sealing lugs on the partition.

Good intermixing of the consolidating material or the adhesive is achieved in that the mixer head has slots having an oblique or twisting course and made continuous from the under side to the upper side.

Likewise for easier arresting or the rod, serving as cartridge, within the drill hole and to prevent unintended escape of adhesive composition out of the bore, the lower end of the rod has a sealing bead which at the same time serves to contribute to keeping the slot penetrating the partition as small as possible.

Further detaiis and advantages of the object of the invention appear from the following description of the accompanying drawing, in which a preferred example of embodiment is illustrated with the necessary details and indvidual parts and wherein:- Figure 1 shows a cross-section through a consolidated and anchored roadway, Figure 2 shows a drill hole with rod introduced, Figure 3 shows a drill hole with a rod in section, Figure 4 shows another embodiment of the rod with bores arranged in distribution over the length, Figure 5 shows a cross-section through a gallery in the region of the working face, Figure 6 shows a cross-section through a rod serving a cartridge, Figure 7 shows a longitudinal section throug a rod serving as cartridge, Figure 8 shows a lateral elevation of the rod, Figure 9 shows the lid region of the rod according to Figure 7, and Figure 10 shows several rods serving as cartridges, connected with one another, in lateral elevation.

The roadway as represented in Figure i is for example a cross heading which must be additionally secured by reason of winning operations. It can equally be a companion roadway to the workings. The surrounding rock is designated by 2.

Figure 1 shows that when the method as described is used in the surrounding rock 2, a large rock jacket securing the roadway crosssection is produced. This jacket is divided by the rock anchors 4, 5 into the zone 6 and by the injection of the consolidating material into the zone 7, the two zones 6, 7 nevertheless forming one unit. Only in the region of each bore hole mouth is a zone 8 formed which is penetrated very little, if at all, by the consolidating material that is it is practically only stuck. A roadway secured in this way can take up very high stresses, and even alternating stresses.

In Figures 2 and 3 there are shown rock anchors 4 which are introduced into a drill hole 9.

It is indicated here that the rock anchors 4 are each not pushed up to the deepest part 1 7 of the drill hole, but rather a more or less large cavity remains which is filled with consolidating material in the injection. Thb rods 10 as illustrated are tubular stock. The rods 10 consisting of a highly elastic material have for example a plate 11 at the roadway end 1 3. This plate 11 firstly prevents the escape of the consolidating material. For the attachment of the high-pressure pump the rod 10 has a threading 14 at the roadway end 13. By means of this threading 14 it is possible to attach the high-pressure hose 1 5 or equally plates or suspension hooks for the monorail suspended railways for example.Such rock anchors 4, 5 or rods 10 are in fact also used to ever greater extents to constitute a secure suspension for the monorail suspended railways, supply conduits and cables, and such working equipment.

The escape of consolidating material over the roadway edge 1 6 is prevented by means of the sealing collars 20 which are fitted, at a specific distance from the mouth 1 8 of the drill hole, in the lower part 21 of the rod 10.

The arrows in Figure 2 and 3 indicate that the consolidating material penetrates, by way of highpressure pump and the high-pressure hose 15, through the tube shell 12 into the drill hole 9 and then by way of fissures 23 into the rock 2. The sealing collar 20 with the bores 22 ensures that the consolidating material penetrates only with low pressure into the region, so that it does not then force its way forward beyond the roadway edge 16.

In place of the sealing collars 20, in the variant of the rod 10 shown in Figure 3, annular zones 24, 25 are provided in which the tube shell 12 is attenuated. At the tip 19 a valve flap or several valve flaps 26 is or are formed, which ensure that before the consolidating material penetrates into this region firstly such a high pressure develops within the tube shell 12 that the annular zones 24, 25 are inflated into beads. These beads place themselves tightly against the wall of the drill hole and prevent penetration of the consolidating material.

In the upper region of the rod 10, or in distribution over its whole length, barbs 27 are provided which are intended to prevent premature slipping of the anchor out of the drill hole 9 and at the same time increase the adhesion in the drill hole 9 filled with consolidating material.

Figure 4 shows a tubular spike suitable for example for the consolidation of coal which tends to run out. The tubular spike is designated by 30 and consists, like the rod 10 as shown in Figures 1 to 3, of highly elastic material in which bores 31, 32, 33, 34 are formed in distribution over the length. At the lower end of the tubular spike 30 there is provided a quick-acting catch 35 with a ball valve 36. By means of the seal 37 the consolidating material is prevented from overflowing into the interior of the roadway.

The upper end is closed by means of a stopper 38 which comprises a cap 39 and an insertion end 40 by means of which the stopper 38 is fitted upon the tubular spike 30.

Figure 5 shows the use of tubular spike 30 in the gallery. For this purpose firstly cartridges 43 with consolidating material are introduced into the drill hole 9, and are then broken by means of tubular spike 30 so that the consolidating material can penetrate into the strata 42 formed in the seam 41 and also into the tubular spike 30 itself. In this way the coal face 46 is consolidated in the region between roof 44 and floor 45 so that an approximately perpendicular face is guaranteed.

Incidentally 47 designates the trough within the quick-acting catch 35, upon which the ball of the valve 36 can rest in order effectively to prevent consolidating material from flowing out of the tubular spike 30.

Figures 6, 7, 8, 9 show a rod 10 which is at the same time formed as a cartridge 51 accommodating consolidating material. For this purpose the cartridge 51 comprises two mutually separate chambers 52, 53 which are formed due to the fact that the interior 59 of the cartridge 51 is divided by the partition 68 into the two chambers 52, 53. At the upper end 69 the partition 68 is connected with a mixer head 71 which is seated fixedly or rotatably on the partition 68. The lower end 70 of the partition 68 is conducted out beyond the end piece 72 and has several apertures 74 in the protruding part 75, by means of which the extraction of the partition 68 from the cartridge 51 is to be facilitated. The end piece has an appropriately formed slot 73 for the passage of the partition 68.

The mixer head 71 has a plurality of slots 79, 80 extending through from the under side 77 to the upper side 78. These slots serve, on actuation of the partition 68, to permit the displaced consolidating material to penetrate into the free space then forming above the mixer head 71. The slots 79, 80 are here so formed and shaped that correct intermixing of the components stored in the two chambers 52, 53 is ensured. Premature mixing or reaction of the components stored in the chambers 52, 53, in the region of the lid 81, is effectively prevented by sealing stoppers 82, 83, which, as shown by Figure 9, are introduced into the slots 79, 80. The stoppers 82, 83 are expediently part of the lid 81.

To facilitate the actuation of the partition 68 and to guarantee the sticking of the cartridge 51 as a whole in the drill hole, the side edges 85, 86 of the partition 68 are made in dovetail form and guided in a guide 90. In the region of the guide, that is in the region where the walls of the chambers 52, 53 are attenuated, apertures 87, 88 are provided by way of which the mixed consolidating material can penetrate into the interspace between the cartridge 51 and rock 2. It can here be expendient, as shown in Figure 6, to form seal tabs 91 in the region of each of the side edges 85, 86. It is likewise advantageous to form seal washers 92 in the region of the slot 73 at the end piece 72, in order effectively to prevent escape of the consolidating material through the slot 73 in the end piece 72. The slot 73 is here at the same time constricted as far as possible and necessary in that on the outer periphery of the cartridge 51 a sealing bead 93 isfittedwhich at the same time also leads to a sealing of the lower region and better arresting of the cartridge 51 in the drill hole.

Figure 10 shows several cartridges 51, 96, 97 connected with one another, which are stored as such and if necessary separated by means of the cut-away or tear-away seams 95, 98 and used singly. For this purpose the intermediate pieces 94 are formed which are intended additionally to prevent the escape of the consolidating material from the individual cartridges 51, 96, 97.

Claims

1. Method for consolidating rock strata in mining and tunneling, in which the consolidating material is injected under pressure into and/or through prepared drill holes into the rock, characterized in that simultaneously with the consolidation of the rock, anchors or spikes are introduced and stuck with the consolidating material in the drill hole.

2. Method according to Claim 1, characterised in that the consolidating material is introduced under reduced pressure into the region of the mouth of the drill hole.

3. Method according to Claim 1, characterised in that foaming or non-foaming adhesive composition of good adhesion is used as consolidating material and is forced against and/or into the rock by sections starting from the deepest part of the drill hole, considered over the length of the drill hole.

4. Method according to Claim 1, characterised in that the consolidating material is charged into cartridges and introduced into the drill hole and then the cartridges are broken with the aid of a tubular spike and distributed in the drill hole and at the same time in the tubular spike.

5. Device for the consolidation, especially anchoring, of rock strata according to methods in accordance with Claims 1 to 4, consisting of a rod which when introduced into the drill hole protrudes therefrom by a predetermined amount, characterised in that the rod (10) is made in tubular form.

6. Device according to Claim 5, characterised in that the rod (10) is produced from elastic material of high strength and comprises a connecting or attaching piece (14,35) at the end (13) protruding from the drill hole.

7. Device according to Claims 5 and 6, characterised in that the tube shell (12) is made attenuated in annular form in one or more zones (24, 25), and above these zones a valve flap (26) is arranged seated externally upon the tube shell.

8. Device according to Claims 5 and 6, characterised in that the tube shell (12) comprises bores (31,32, 33, 34) in specific zones (24, 25) or in distribution over the entire length and comprises a quick-acting catch (35) at the lower end (13) protruding from the drill hole (9).

9. Device according to Claim 8, characterised in that the quick-acting catch (35), formed as plug-in fastening with clip, comprises a trough (47) corresponding with a ball valve (36) arranged thereabove in the rod (10).

10. Device according to Claim 8, characterised in that the end of the rod (10) arranged in the drill (9) is closable by means of a stopper (38) with rounded cap (39) and push-in end (40), the cap being formed to protrude beyond the tube shell (12).

11. Device according to Claims 5 and 6, characterised in that the rod (10) has one or more sealing colIars20) formed in the lower part (21) in which there are provided bores (22) of small calibre extending parallel with the rod.

12. Device according to Claims 5 and 6, characterised in that downwardly pointing barbs (27) are formed on the tube shell (12).

13. Device according to Claims 7 to 11, characterised in that the sealing collars (20) and/or the valve flaps (26) are arranged forming sections at the tip (19) and/or over the length of the rod (10).

14. Device according to Claim 5, characterised in that the rod (10) has an internal threading (14) at the roadway end (13).

1 5. Device according to Claims 5, 6 and 8, characterised in that one or more mechanically breakable cartridges (43) filled with consolidating material is or are arranged within the rod (10).

16. Device according to Claims 5, 6 and 8, characterised in that the interior (59) of the rod (10) is divided, forming two chambers (52, 53), by a partition (68) guided in the tube shell (12) and formed for longitudinal displacement, on the end of which partition facing the rod tip (19) there is arranged a mixer head (71).

17. Device according to Claim 16, characterised in that the side edges (85, 86) of the partition (68) are made in dovetail form.

1 8. Device according to Claims 16 and 17, characterised in that the tube shell (12) has, in the region of the guide (90), apertures (87, 88) which are closable from the chambers (52, 53) by the partition (68).

1 9. Device according to Claim 1 6, characterised in that the mixer head (71) comprises slots (79, 80) formed continuously from the under to the upper side (77, 78) and having an oblique or twisting course.

20. Device according to Claims 5, 6 and 16, characterised in that the lower end (13) of the rod (10) serving as cartridge wall comprises a sealing bead (83) which is formed drawn down to the end piece (72), which has the aperture (74) for the drawing through of the partition (68), and surrounding and firmly connected with the tube shell (12).

21. Method for consolidating rock strata in mining and tunneling as claimed in Claim 1 substantially as described herein.

22. Device for the consolidation of rock strata as claimed in Claim 5 substantially as described with reference to the accompanying drawings.