WO2006119607A1

WO2006119607A1 - Explosive-activated ground anchor assembly

Info

Publication number: WO2006119607A1
Application number: PCT/CA2006/000592
Authority: WO
Inventors: Ciro Pasini
Original assignee: Ciro Pasini
Priority date: 2005-05-13
Filing date: 2006-04-13
Publication date: 2006-11-16
Also published as: CA2507344C; CA2507344A1

Abstract

A ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object thereto, the assembly adapted to be received within a borehole within the ground, the assembly comprising an elongate anchor shaft having shaft abutment means on a portion thereof; a plurality of elongate ground-engageable members retained on and moveable along the shaft; each of the members having (i) a first terminal portion operably abutable with the shaft abutment means, and (ii) a second terminal portion operably adjacent an effective explosive charge means adjacent the shaft, whereby detonation of the effective explosive charge effects the movement of the ground-engageable members along the shaft and the abutment with the shaft abutment means as to effect frictional engagement and retention of the first terminal portions within the ground. The assembly also may be used to provide ground anchors within the walls, roof and floors of mine shafts and tunnels.

Description

EXPLOSIVE-ACTIVATED GROUND ANCHOR ASSEMBLY

FIELD OF THE INVENTION

This invention relates to a ground anchor, for use underground in mine shafts, tunnels and the like, or particularly, for tying down structures, such as towers, electricity pylons and the like with guy wires above ground.

BACKGROUND OF THE INVENTION

Utilities and other companies, which use guy towers, use various mechanical devices to anchor the guy wires that hold the towers vertically. Typical installations require than an anchor rod or shaft is held in the ground to provide a holding power sufficient to hold the tower upright under the designed conditions of wind, ice and tower vibrations.

Typical examples of such mechanical anchors known in the art include multi-helix screws, expanding anchors, grouted anchors and wood mats.

Below ground or within mountains and the like, as in mine shafts, tunnels and the like, retained members such as rods, bolts, thick wire members and the like, may be retained in the walls, face, roof or floor of a tunnel within a concrete-filled borehole.

Although the aforesaid prior art is in established use, there is, however, a need for a ground anchor system that provides less disturbance of the ground adjacent the resultant borehole during installation and completion of the installed resultant ground anchor.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a ground anchor assembly which provides a resultant installed ground anchor that minimizes disruption of the annular sides of the borehole and maintains the integrity of the surrounding ground. Accordingly, in one broad aspect the invention provides a ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object thereto, said assembly adapted to be received within a borehole within said ground, said assembly comprising an elongate anchor shaft having shaft abutment means on a portion thereof; a plurality of elongate ground-engageable members retained on and moveable along said shaft; each of said members having

(i) a first terminal portion operably abutable with said shaft abutment means, and (ii) a second terminal portion operably adjacent an effective explosive charge means adjacent said shaft, whereby detonation of said effective explosive charge effects said movement of said ground-engageable members along said shaft and said abutment with said shaft abutment means as to effect frictional engagement and retention of said first terminal portions within said ground. The present invention provides an explosive-activated ground anchor assembly that uses the energy generated by a small charge of explosive located at the bottom of the bore hole below the anchor shaft or within a housing connected to as part of the shaft to propel a plurality of elongate ground-engageable members upwardly on the shaft, whereby the upper end portion of each member is so shaped that upon abutment with a suitably located abutment means, preferably a collar on the shaft, in consequence of the explosion, the upper end portions of the members "splay" outwardly from the shaft and penetrate into the borehole sides of the ground to effect frictional engagement and retention within the ground.

The practice of the invention is equally as practicable when the borehole is horizontal or at any other angle in the ground, with the appropriate charge in directional terminology commensurate with the direction.

In alternative embodiments, the explosive charge means comprises a housing formed of a material selected from a metal, fabric, paper, cardboard and a plastics material.

The housing may be an article separate and distinct from but adjacent the shaft or connected thereto, for example, by welds, or integrally-formed therewith. Preferably, the shaft abutment means constitutes a collar of sufficient width and so located on the shaft as to provide effective operable abutment with the plurality of members to effect proper directional charge of the moving members into the borehole sides. The plurality of members are most preferably retained to and around the shaft by means of a metal ring which embraces and is operably moveable on the shaft. The ring is adjacent the explosive charge whereby detonation thereof causes the upward movement of the ring and associated members along the shaft in a manner analogous to the opening of the retractable spokes of an upsidedown umbrella.

Thus, in a preferred aspect the invention provides a ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object connected thereto, said assembly adapted to be received within a borehole within said ground, and comprising (a) an anchor elongate shaft having a longitudinal axis and a proximal portion and a distal end;

(b) a housing adjacent said distal end of said shaft;

(c) a collar means adjacent said proximal portion of said shaft;

(d) an umbrella assembly between said housing and said collar means, said umbrella assembly comprising

(i) a ring member located and operably moveable on said shaft adjacent said housing; and

(ii) a plurality of elongate members essentially parallel to said longitudinal axis of said shaft, wherein each of said members has a distal end connected to said ring member, and a splayed proximal end portion so shaped relative to said collar means, such that in operation movement of said plurality of elongate members along said shaft effects sufficient abutment of said splayed proximal ends against said collar means as to effect frictional engagement of said proximal end portions of said members within said ground; and

(e) an effective amount of explosive within said housing connectable to detonator means to effect detonation of said explosive to operably propel said umbrella means along said shaft to effect said sufficient abutment of said splayed proximal ends against said collar means.

Penetration of the members to a typical depth of 3-15cm depending on the nature of the ground material and as determined by the skilled person has been found to be effective in achieving effective retention.

In a further aspect, the invention provides a system comprising an object restrained by an object anchor means to or within the ground comprising said object; an elongate anchor; means for connecting said anchor to said object; and ground retaining means for retaining said anchor within said ground; the improvement comprising said anchor retaining means comprising a plurality of elongate ground-engaged members, wherein each member has a proximal portion retained to said anchor, and a distal portion in frictional engagement and retention within said ground.

In a further aspect, the invention provides a method of constructing a system comprising an object restrained to the ground with restraining anchor means comprising an elongate anchor disposed within said ground and attachment means attached to said anchor and said object; said method comprising the steps of locating said anchor within a borehole in the ground and attaching said anchor to said object; the improvement comprising (a) providing said anchor comprising an anchor elongate shaft; a housing connected to said shaft and surrounding at least a part of said anchor shaft; said housing with said part of said shaft defining a chamber; and an effective amount of an explosive within said chamber connectable to detonator means to effect detonation of said explosive to effect deformation of said housing as to provide frictional ground retention of said housing within said ground;

(b) providing said effective explosive charge means adjacent said shaft;

(c) detonating said explosive charge to effect said movement of said ground- engageable members along said shaft and said abutment with said shaft abutment means to effect frictional engagement and retention of said first terminal portions within said ground.

The anchor assembly as hereinabove defined my be used in above and below ground situations, e.g. for tying down structures, such as towers, buildings or the like, as well as in mine shafts, tunnels below ground or within mountains as providing shaft, rod or thick wire members retained in the walls, face, or roof of a tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be better understood, preferred embodiments will now be described by way of example only, with reference to the accompanying drawings, wherein Fig. 1 is a diagrammable vertical cross-section of an explosive-activated anchor assembly according to the invention, within a borehold, prior to detonation;

Fig. 2 is a diagrammatic vertical cross-section of an exploded assembly according to the invention exemplified by Fig. 1 after detonation; and wherein the same numerals denote like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Fig. 1, this shows generally as 10, an assembly according to the invention having a steel, elongate anchor or rod shaft 12 disposed within a borehole 14 having sides 16 and a bottom 18. Top of rod 12 has an eyehole 20 to be subsequently connected by line 22 to pylon or tower 24.

Shaft 12 has a steel collar abutment means 26 welded thereon at a location suitable, typically, midway of the length of shaft 12, as determined by the skilled person, for the practice of the invention. Shaft 12 at its end 28 distal to eye 20 has a tapered, ground entering housing 30 containing an effective amount of explosive 32, sufficient upon detonation, to upwardly propel ring 34 enbracing and operably upwardly moveable on shaft 12. Connected to ring 34, are the distal ends 36 of a plurality of elongate members 38, which members 38 are disposed symmetrically around shaft 12 between collar 26 and housing 30. Members 38 are essentially parallel to shaft 12, analogous to the spokes of an upside down umbrella in a closed manner. The end portions 40 of members 38 proximal to collar 26 are gently splayed outwardly of shaft 12 to a sufficient degree as to effectively, operatively, and sufficiently, abut collar 26 with such force as to cause ends 40 and, subsequently, members 38 to further splay outwardly of shaft 12 under the explosive force acting upon and propelling ring 34 upwardly along shaft 12. In consequence, with reference also to Fig. 2, ends 40 and sufficient lengths of members 38 penetrate borehole sides 16 and become embedded in frictional abutment in the ground. The aforesaid embodiment has been described with reference to the anchor assembly being placed in a vertical borehole. However, it will be understood that the assembly may be placed at an angle with respect to the ground, as is known in the art.

Members 38 may be produced to operably penetrate to a depth of, typically 5-8cm, but also 15cm or greater, if desired, by judicious selection of component dimensions and materials, typically steel, and the amount and type of explosive and disposition with respect to the nature of the ground.

As known in the prior art, anchor rods/shafts may be provided in modular form suitably adapted to be joined one shaft to another in Im, 2m or 3m sections to give a desired total suitable length for use within the borehole. Thus, several assemblies according to the present invention, may be extended into a single joined shaft.

The assemblies according to the invention may be selectively used in all types of ground, such as, for example, limestone strata, granite, Canadian Shield strata, soft soils, sands and permafrost. A major intention of the practise of the invention defined herein is to try and maintain the integrity of the ground surrounding the borehole and to not disrupt the majority of the annular sides around the resultant positioned anchor, with the minimum of breakaway of the sides of the ground.

Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated.

Claims

Claims:

1. A ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object thereto, said assembly adapted to be received within a borehole within said ground, said assembly comprising an elongate anchor shaft having shaft abutment means on a portion thereof; a plurality of elongate ground-engageable members retained on and moveable along said shaft; each of said members having

(i) a first terminal portion operably abutable with said shaft abutment means, and (ii) a second terminal portion operably adjacent an effective explosive charge means adjacent said shaft, whereby detonation of said effective explosive charge effects said movement of said ground-engageable members along said shaft and said abutment with said shaft abutment means as to effect fractional engagement and retention of said first terminal portions within said ground.

2. An assembly as defined in claim 1 wherein said explosive charge means comprises a housing formed of a material selected from a metal, fabric, paper, cardboard and a plastics material.

3. An assembly as defined in claim 2 wherein said housing is connected to said shaft.

4. An assembly as defined in any one of claims 1 to 3 wherein said shaft abutment means comprises a collar.

5. An assembly as defined in any one of claims 1 to 4 wherein said elongate ground- engageable members are arranged symmetrically around the longitudinal axis of said shaft.

6. An assembly as defined in any one of claims 1 to 5 wherein each of said first terminal portions of said ground-engageable members are splayed radially outwardly of said longitudinal axis.

7. An assembly as defined in any one of claims 1 to 6 wherein each of said second terminal portions are connected to a ring member retained and operably moveable on said shaft.

8. A ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object connected thereto, said assembly adapted to be received within a borehole within said ground, and comprising (a) an anchor elongate shaft having a longitudinal axis and a proximal portion and a distal end;

(b) a housing adjacent said distal end of said shaft;

(c) a collar means adjacent said proximal portion of said shaft; (d) an umbrella assembly between said housing and said collar means, said umbrella assembly comprising

(ii) a plurality of elongate members essentially parallel to said longitudinal axis of said shaft, wherein each of said members has a distal end connected to said ring member, and a splayed proximal end portion so shaped relative to said collar means, such that in operation movement of said plurality of elongate members along said shaft effects sufficient abutment of said splayed proximal ends against said collar means as to effect frictional engagement of said proximal end portions of said members within said ground; and (e) an effective amount of explosive within said housing connectable to detonator means to effect detonation of said explosive to operably propel said umbrella means along said shaft to effect said sufficient abutment of said splayed proximal ends against said collar means.

9. An assembly as defined in any one of claims 1 to 8 wherein said effective charge is sufficient to effect said frictional engagement and retention of said first terminal portions within said ground to a ground thickness selected from 3-15 cm.

10. An assembly as defined in any one of claims 2 to 9 wherein said elongate anchor has a tapered, ground-entering terminal portion.

1 1. A system comprising an object restrained by an object-anchor means to or within the ground comprising said object; an elongate anchor; means for connecting said anchor to said object; and ground retaining means for retaining said anchor within said ground; the improvement comprising said anchor retaining means comprising a plurality of elongate ground-engaged members, wherein each member has a proximal portion retained to said anchor, and a distal portion in frictional engagement and retention within said ground.

12. A system as defined in claim 10 wherein each of said proximal portions of said elongate members is connected to a ring member which embraces and is retained on said anchor.

13. A system as defined in claim 10 or claim 11 wherein said elongate members are symmetrically disposed radially around said anchor.

14. A system as defined in any one of claims 11 to 13 wherein said object-anchor means comprises a guy wire, strut or like member.

15. An assembly as defined in any one of claims 1 to 10 or a system as defined in any one of claims 11 to 14 wherein said object is an above ground structure.

16. A system as defined in claim 15 wherein said above ground structure is selected from the group consisting of a tower and a pylon.

17. An assembly as defined in any one of claims 1 to 10 or a system as defined in any one of claims 11 to 14 wherein said object is located within a mine or other subterranean location.

18. A method of constructing a system comprising an object restrained to the ground with restraining anchor means comprising an elongate anchor disposed within said ground and attachment means attached to said anchor and said object; said method comprising the steps of locating said anchor within a borehole in the ground and attaching said anchor to said object; the improvement comprising (a) providing said anchor comprising an elongate anchor shaft having shaft abutment means on a portion thereof; a plurality of elongate ground-engageable members retained on and moveable along said shaft; each of said members having

(i) a first terminal portion operably abutable with said shaft abutment means, and (ii) a second terminal portion operably adjacent an effective explosive charge means adjacent said shaft, whereby detonation of said effective explosive charge effects said movement of said ground-engageable members along said shaft and said abutment with said shaft abutment means as to effect frictional engagement and retention of said first terminal portions within said ground. (b) providing said effective explosive charge means adjacent said shaft; and (c) detonating said explosive charge to effect said movement of said ground- engageable members along said shaft and said abutment with said shaft abutment means to effect frictional engagement and retention of said first terminal portions within said ground.

19. A method as defined in claim 18 wherein said explosive charge means comprises a metal housing connected to said shaft and containing said effective amount of said explosive.

20. A method as defined in claim 18 or claim 19 wherein said anchor comprises a ground anchor retaining means assembly for providing a ground-retained anchor retaining means to restrain an object connected thereto, said assembly adapted to be received within a borehole within said ground, and comprising

(a) an anchor elongate shaft having a longitudinal axis and a proximal portion and a distal end;

(b) a housing adjacent said distal end of said shaft;