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Patent Searching and Data


Title:
METHOD OF DRILLING A TUBULAR SLOT
Document Type and Number:
WIPO Patent Application WO/2002/099203
Kind Code:
A1
Abstract:
This invention describes a method of locating a foundation member comprising drilling a first hole (13), drilling a second hole (13) alongside the first hole (13) so that it overlaps with the first hole (13), drilling successive holes (13) that each overlap with the previous hole (13) and drilling all of the holes (13) along a set path to form a slot (14) and locating and fixing a foundation member (10) within the slot. The invention provides an alternative means of locating a foundation member by comparison to excavation processes.

Inventors:
Nicholls, John (136 Daws Road Melrose Park, South Australia 5039, AU)
Application Number:
PCT/AU2002/000713
Publication Date:
December 12, 2002
Filing Date:
June 05, 2002
Export Citation:
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Assignee:
SDS CORPORATION LIMITED (136 Daws Road Melrose Park, South Australia 5039, AU)
Nicholls, John (136 Daws Road Melrose Park, South Australia 5039, AU)
International Classes:
E02D17/13; E02D27/42; E02F5/16; E02D5/28; (IPC1-7): E02D27/42; E02D5/28; E02D5/74; E02D7/00; E02D17/13
Domestic Patent References:
WO2001066861A1
Attorney, Agent or Firm:
Madderns (Level 1 64 Hindmarsh Square Adelaide, South Australia 5000, AU)
Download PDF:
Claims:
THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:
1. A method of locating a foundation member comprising: drilling a plurality of overlapping holes along a set path to form a slot along said path, and locating and fixing a foundation member within said slot.
2. A method according to claim 1 wherein said path returns to said first hole.
3. A method according to claim 1 wherein said path is circular.
4. A method according to claim 1 wherein said foundation member is a plate having a thickness that is equal or less than the width of overlap between adjacent holes.
5. A method according to claim 4 wherein said foundation member comprises a tubular member having a thickness that is equal or less than the width of overlap between adjacent holes.
6. A method according to claim 5 wherein said tubular member comprises a cylindrical tube.
7. A method according to claim 5 wherein part of said tubular member comprises a cylindrical tube.
8. A method according to claim 7 wherein the remainder of said tubular member comprises rods fixed to and extending from said cylindrical tube.
9. A method according to any one of claims 5 to 8 wherein said tubular member has a flange on its upper end.
10. A method according to any one of the preceding claims wherein said foundation member is fixed into said slot by cement.
11. A method of locating a foundation member comprising: drilling a first hole, drilling a second hole alongside said first hole so that it overlaps with said first hole, drilling successive holes that each overlap with the previous hole and drilling all said holes along a set path to form a slot, and locating and fixing a foundation member within said slot.
12. A method of locating a foundation member substantially as herein described with reference to the accompanying drawings.
13. A foundation formed in accordance with any one of the methods referred to in claims 1 to 11.
Description:
METHOD OF DRILLING A TUBULAR SLOT This invention relates to the drilling of a slot and using the drilled slot for locating and fixing a foundation member.

A further aspect of this invention is the method of forming a foundation using a drilled tubular slot.

Some buildings or structures use foundation members that comprise a steel tube which is cemented into ground. The steel tube provides a footing to which a structure or building may be attached.

As an example, such foundation members are commonly used in the construction of towers such as lighting towers or towers used to hold wind generating turbines. The foundation member comprises a steel tube that is referred to as a steel can. They are generally three to four metres in diameter, generally eight metres in height and have a wall thickness of 15-30mm.

Current techniques for locating such steel cans within the ground are to excavate a square cross-section hole of the required depth. The steel can is then lowered into place with the centre of the can being back filled with material removed during the excavation process. Cement is then placed between the wall of the excavated hole and the steel can.

Such a construction process is time consuming, particularly when the excavation of the hole is in hard or consolidated ground. Blasting and other rock braking techniques are normally used. Apart from being time consuming it is also a costly aspect of the construction process.

It is an object of this invention to provide an improved means of locating steel cans and similar foundations into the ground and to therefore overcome the problems of time and cost associated with current techniques.

In its broadest form, the invention is a method of locating a foundation member comprising: drilling a plurality of overlapping holes along a set path to form a slot along said path, and locating and fixing a foundation member within said slot.

In the case of a steel can, the plurality of holes are drilled around a circular path.

They overlap to an extent that provides a slot having a width which is equal to or greater than the thickness of the steel can. The depth to which the holes are drilled equals or is greater than the height of the steel can. This provides a continuous slot which is equal to or greater than the thickness of the steel can at a diameter which enables the steel can to be simply dropped into the ground. The process is completed by pouring cement on either side of the steel can to permanently locate it within the tubular slot.

This method of forming a tubular slot preferably uses conventional rock drilling technology, such as pneumatically operated down hole hammers, which enable holes to be drilled to the required depth in a wide range of ground formations. This includes hard and consolidated rock structures as well as sandstones, clay and even some alluvial deposits. In order to drill overlapping adjacent holes, a guide is fitted to the hammer which locates in the hole that has already been drilled to prevent the hammer deviating into that hole and to maintain a constant overlap. An example of a means for guiding the drilling of the slot is a plate or guide structure having a cut out slot the width of the holes being drilled that matches the shape of the slot to be drilled. It can be used as a template to guide the drilling equipment.

Although it is common to use cylindrical tubes as the steel cans, other shapes such as ellipses, triangular, square and other rectilinear shapes may be used. This enables a greater variety of shapes to be fabricated particularly where such shapes may be more desirable than circular or cheaper to produce. The shape of the guide slot in the template can be varied accordingly. Also, the template may comprise only part of the slot with the template being moved to complete the full ground slot.

This invention also includes other forms of slots within which foundation members can be located. These may include straight slots, or partly circular slots, or segments on a circular path. For example, instead of using a cylindrical steel can, a number of curved segments may be located within the ground in a generally circular line so as to form a foundation.

Further, the foundation member may vary from a plain cylindrical tube. For example, part of the foundation member may comprise a cylindrical tube with the remainder comprising rods that are fixed to and extending from the cylindrical tube.

The rods may be spaced around the periphery of the cylindrical tube and have circular tie members spaced along their length to hold the rods in a generally circular form. Such an arrangement has the advantage of significantly reducing costs of the foundation member while at the same time not compromising the strength or integrity of the foundation member.

In order for the invention to be fully understood, preferred embodiments will now be described. However, it should be realised that the scope of this invention is not to be confined or restricted to the precise combination described in these embodiments.

The embodiments are illustrated in the accompanying drawings in which: Fig 1 shows a foundation member comprising a steel can; Fig 2a and 2b show overlapping holes drilled in the ground and the slot formed in the ground respectively; Fig 3 shows a cross-sectional view through the drilled holes with the steel can in place; Fig 4 shows a second embodiment of a foundation member comprising a part steel tube and attached rods; and Fig 5 shows the foundation member of Fig 4 inserted in a drilled tubular slot.

Fig 1 shows a foundation member 10 that has a tubular wall 11 and a flange 12 attached at the upper end of the tubular wall. The tubular wall 11 has a thickness of between 15 and 30mm, is approximately 3 to 4 metres in diameter and approximately 8 metres in height.

The conventional technique for inserting the foundation member 10 into the ground involves digging a square hole of greater than 4 metres in width and 8 metres deep.

The foundation member is then placed into the hole and held in position prior to concrete being poured around the tubular wall 11. Fill material from the excavation process can then be used to fill the centre of the tubular wall 11.

The invention comprises the drilling of a number of adjacent overlapping holes 13 as shown in Fig 2a and 2b. These holes 13 are preferably drilled using pneumatic down hole drilling equipment although other drilling techniques may be used. A guide is attached to the hammer or a guide is inserted within the previously drilled hole which allows the overlap hole to be drilled by preventing the drilling equipment from veering off-line into the already drilled hole.

By drilling the holes 13 on a circular path having the required diameter and by ensuring sufficient overlap, the result is a slot 14 within which the tubular wall 11 of the foundation member 10 can locate. The width of the overlap between adjacent holes 13 can be increased to provide sufficient clearance to enable the tubular wall 11 to easily locate within the resultant slot 14. Fig 3 illustrates the tubular wall 11 located within the slot 14. The tubular wall 11 is fixed with respect to the slot 14 by pouring cement on either side of the tubular wall 11. This fixes the foundation member 10 in place.

Fig 3 also illustrates the location of a conduit 16 that can be formed within the ground to enable electricity cables or pipelines to enter within the structure placed on the foundation member 10. The hole 17 is formed in the tubular wall 11.

Fig 4 and 5 show a second embodiment of the foundation member 10. In this embodiment the tubular wall 11 comprises a first tubular wall 19 and a plurality of rods 20 fixed to the first tubular wall 19 that extend downwardly therefrom. The rods 20 are spaced evenly around the periphery of the first tubular wall 19. Circular stays 21 are located around and fixed to each of the rods 20 and are spaced at intervals along the length of the rods 20. Spacers 22 are positioned on the ends of some of the rods 20 to assist in centralising the rods 20 within the slot 14.

Fig 5 shows the foundation member of Fig 4 located within a slot 14. The illustration also shows a structure 24 attached to the flange 12. As with the first embodiment, the foundation member 10 is secured in the slot 14 by cement being poured into the slot on either side of the first tubular wall 19.

As can be seen by the above description, the invention provides a quick and easy means of forming a recess into which the foundation member 10 can locate. It is clearly the much quicker method of forming the foundation by comparison to currently available means.