GB2457049A

GB2457049A - Concrete Pile Forming

Info

Publication number: GB2457049A
Application number: GB0801722A
Authority: GB
Inventors: Roger Alfred Bullivant
Original assignee: ROXBURY PATENTS Ltd
Current assignee: ROXBURY PATENTS Ltd
Priority date: 2008-01-31
Filing date: 2008-01-31
Publication date: 2009-08-05
Also published as: GB0801722D0

Abstract

A concrete pile forming device 10 consisting of an elongate probe 12 having an oversized section 20 which at least in part extends further from the axis 14 of the probe than the probe itself. The probe 12 extends to a tip 16 beyond the oversized portion 20 and the probe tapers to a point at the tip 16. The oversized portion 20 causes the outline of the hole formed when the probe is driven 66 to be spaced from the probe sides 18. The oversize portion 20 may be a collar or ring carried on the probe which is a planar member orientated perpendicular from the probe axis. The probe 12 may be mechanically coupled 50 to the collar 20 and the probe 12 may be disengaged from the oversized collar 20 when the probe 12 is withdrawn leaving the ring in the ground. The probe 12 comprises a passage, which may pass through the probe or the probe may be hollow, for a pile forming liquid such as concrete or cement, and has at least one mouth (fig 5, 30) allowing the liquid to flow into the hole formed. At least one of the mouths may be between the tip 16 and the oversized portion or at the tip (fig 5, 30) or be situated further from the tip than the oversized collar 20. The openings are covered 34 to prevent ingress of material when the probe is driven. The method of using the probe 12 is by driving it into the ground and introducing the pile forming liquid as the probe is being driven or withdrawn.

Description

Hole Formation The present invention relates to hole formation and apparatus and methods for use in forming holes.

S

There is a requirement for forming holes in the ground for various purposes, including the construction of foundation components.

Embodiments of the present invention provide apparatus comprising: an elongate probe having an axis, a tip and an outline when viewed along the axis toward the tip, and an oversize portion having an outline, when viewed along the axis, toward the tip, which is further from the probe axis than the probe outline is from the probe axis, around at least part of the probe outline; wherein the probe extends beyond the oversize portion to the tip, and wherein, when the probe and the oversize portion are driven into the ground to form a hole in the ground, the probe engages the ground before the oversize portion engages the ground, and the oversize portion causes the outline of the hole wall to be spaced from the outline of the probe around at least said part of the probe outline.

Substantially the whole of the outline of the oversize portion may be further from the probe axis than the probe outline is from the probe axis. The oversize portion may be a collar carried by the probe. The collar may be a planar member oriented substantially perpendicular to the probe axis.

There may be a mechanical coupling arrangement operable between the oversize portion and the probe to cause the oversize portion to be driven into the ground by movement of the probe. The mechanical coupling may disengage when the probe is withdrawn, to leave the oversize portion in the ground.

The leading end of the probe may taper to the tip. The tip may be pointed. The tapered region may lie between the tip and the position of the oversize portion when the probe is being driven.

The apparatus may further comprise a passage for a flowable medium and having at least one mouth through which the flowable medium can pass into the hole formed by the apparatus. The passage may pass through the probe. The probe may be hollow to provide the passage.

The position of the oversize portion, when the probe is being driven, may be further from the tip than the mouth or one of the mouths is from the tip. The or one of the mouths may be at the tip. The, or one of the mouths, may be further from the tip than the position of the oversize portion when the probe is being driven. The or each mouth may be provided with a cover to prevent ingress of material while the probe is being driven. The cover may be left in the ground as the probe is withdrawn.

In another aspect, examples of the invention provide a method for forming a hole for a foundation component in the ground, in which apparatus according to any of the preceding definitions is provided, the probe and oversize portion are driven into the ground to create a hole which has a hole wall spaced from the outline of the probe around at least part of the probe outline, and the probe is removed to leave a hole in the ground.

Pile forming material may be introduced into the hole as the probe is being withdrawn. Pile forming material may be introduced into the hole as the probe is being driven.

Examples of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which: Fig. 1 is a vertical section through a probe which is an example embodiment of the present invention; Figs. 2 and 3 are views of alternative arrangements, in section and along the central axis, toward the tip of the probe of Fig. 1; Figs. 4 and 5 illustrate the probe of Fig. 1 in use; and Fig. 6 illustrates the pile formed in the manner shown in Figs. 4 and 5.

Figure 1 illustrates an example of apparatus according to the invention. The apparatus 10 is in the form of an elongate probe 12 having an axis 14, a tip 16 and an outline 18 to be described in more detail with reference to Fig. 2.

An oversize portion 20 is also provided, shown disassembled and enlarged in figure 1. The oversize portion 20 has an outline 22 to be described in more detail with reference to Fig. 2.

When the probe 12 and the oversize portion 20 are driven into the ground to form a hole in the ground, the probe 12 extends beyond the oversize portion 20, to the tip (Fig. 1). The probe 12 engages the ground before the oversize portion 20 engages the ground. The oversize portion 20 causes the hole formed to have a wall spaced further from the axis 14 than the outline of the probe 12 is spaced from the axis 14, around at least part of the outline of the probe 12, so that space exists between the probe and the wall of the hole. This will be described in more detail below.

The apparatus 10 has a generally circular cylindrical portion 24, which is hollow to provide an internal passage 26 along the length of the probe 12, from an inlet 28 to a mouth 30. An end region 32 of the probe 12 is tapered to reduce in diameter toward the extreme tip 16. A cap 34 is provided for closing the mouth 30 at the tip 16 and consists of a plate portion 36 and a locating peg 38 which can be received within the mouth 32 to position the cap 34 in the mouth 30.

The inlet 28 is in the form of a generally transverse pipe 40 coupling to a supply of flowable medium (Fig. 5) during use. The flowable medium entering the probe 12 through the inlet 28 is able to move through the probe 12, by the passage 26, to the mouth 30.

At the opposite end to the tip 16, the probe 12 carries an anvil 42 of robust construction against which driving forces can be exerted, by driving apparatus 44, such as a vibrator or hammer.

The oversize portion 20, in this example, is in the form of a circular ring formed from plate material, such as sheet steel, having a central hole 46 which is the same shape and size as the outer surface of the cylindrical part of the probe 12.

Close to the line 48 at which the tapered region 32 meets the main cylindrical part of the probe 12, the outer surface of the probe 12 is provided with one or more locator projections 50. The hole 46 allows the oversize portion 20 to be fitted over the tip 16 to sit around the probe 12 like a collar, being prevented from sliding past the locator projections 50, by mechanical engagement between the collar 20 and the projections 50. It can readily be understood from figure 1 that the locator projections 50 limit how far the collar 20 may move away from the tip 16 (while remaining located around the probe 12), but do not prevent the collar being moved back to the tip 16, or off the tip.

In this example, a single locator projection 50 is illustrated as a circumferential rim extending continuously around the probe 12.

Figure 2 further illustrates the geometry of the probe 12 and collar 20, when the collar 20 is fitted over the probe 12 and moved into engagement with the circular locator projections 50. Fig. 2 is a view along the axis 14, toward the tip 16 and S shows various circular outlines, as follows. Fig. 2 is a sectional view. The material of the probe 12 is therefore shown in section around the passage 26, and the outline 18 of the probe 12 is visible, centred at the axis 14. The locator projection 50 is visible around the probe 12. The outermost of the various circular outlines is the outline 22 of the collar 20.

Accordingly, it can be seen from Fig. 2 that the outline 22 of the oversize portion 20, when viewed along the axis 14, toward the tip 16, is further from the probe axis 14 than the probe outline 18 is from the probe axis 14. This condition applies around the whole of the probe outline 18.

Figure 3 illustrates an alternative example. In this example, the Construction of the probe 12 is as described above. The outline 22a of the collar 20a differs from the outline of the collar 20 described above. In the example of Fig. 3, the outline 22a is star shaped. The points 52 of the star extend out from the probe 12. The concave portions 54, between the points 52, lie closer to the axis 14 than do the points 52. In this example, the concave portions 54 lie outside the outline of the locator projection 50, but alternatively could lie underneath the projection 50.

Accordingly, it can again be seen that the outline 22a of the oversize portion 20a, when viewed along the axis 14, toward the tip 16, is further from the probe axis 14 than the probe outline 18 is from the probe axis 14. Again, this condition applies around the whole of the probe outline 18.

Many other shapes could be envisaged for the oversize portion 20. For many, the outline of the oversize portion will lie outside the outline of the probe around the whole circumference of the probe. For others, the outline of the oversize portion, when viewed along the axis, toward tip, may only be further from the probe axis 14 than the probe outline 18 is from the probe axis 14, around part of the probe outline 18.

The remaining figures illustrate the manner in which the apparatus described above can be used during the formation of a hole in the ground, which may be a hole formed for forming a foundation component in the ground, for example.

Fig. 4 illustrates the probe 12 being driven into the ground 56, with the axis 14 JO generally vertical. Driving is achieved by the action of the drive apparatus 44 on the anvil 42.

Before the pointed tip 16 of the probe 12 penetrates the ground 56, a collar 20 is fitted over the tip 16. As the tip 16 drives into the ground 56, the collar 20 bears against the ground, generally at 58, which results in the collar 20 being forced up the probe 12 until mechanically engaging with the locator projection 50.

Thereafter, further downward drive of the probe 12 is conveyed to the collar 20 through the locator projections 50, causing.the collar 20 to be driven down. In this condition, as can clearly be seen in Fig. 4, the probe 12 (particularly the tapered end region 32) extends beyond the collar 20, to the extreme tip 16. The probe 12 therefore leads the collar 20, to engage the ground before (below) the collar 20 engages the ground.

This results in a hole being formed in the ground 56. At the lower extremity 60, the hole is tapered in a shape which is complementary with the shape of the tip 16. Above the tapered region, a horizontal ledge 62 steps out to a vertical wall 64 left behind by the outline 22 of the oversize portion 20, as it is forced down through the ground 56.

While the tip 16 is being driven into the ground 56, the mouth 30 is closed by the cap 34 to prevent the ingress of soil or other material into the probe 12.

The geometry of the outlines 18, 22 of the probe 12 and the oversize portion 20, as described above with reference to figs 2 and 3, results in a gap 66 forming above the collar 20, between the probe 12 and the vertical wall 64. As the probe 12 is driven further down into the ground 56, no skin friction arises between the wall 64 and the outer surface of the probe 12 above the collar 20, by virtue of the gap 66. Accordingly, the driving force required for the probe 12 is expected to be reduced significantly as compared with a similar arrangement without the collar 20, in which case there would be contact and friction resistance between the probe 12 and the walls of the hole being formed, along the whole length of the probe 12.

When the probe 12 has been driven down to the required depth, driving force is then reversed to raise the probe 12 out from the ground 56. Figure 5 illustrates the probe 12 after partial withdrawal. Prior to withdrawal beginning, the inlet 28 is connected through appropriate pipework 68 to a pump 70 supplying flowable material from a hopper 72. The flowable material may be concrete, cement or other cementitious material for use in forming a pile. The material is pumped into the inlet 28 and down through the passage 26 to the mouth 30. The material is settable after pumping into the ground, for example to form a pile.

As the probe 12 rises in the ground 56, the cap 34 falls out of the mouth 30 to be left in the ground as a sacrificial component. Similarly, the probe 12 slides up through the collar 20, without lifting the collar. The collar 20 remains as another sacrificial component, on the ledge 62. As the probe 12 continues to withdraw, material pumped through the probe 12 leaves through the mouth 32 to backfill the hole, as the probe 12 withdraws.

Eventually, the probe 12 leaves the ground, having fully backfilled the hole with a settable material, as illustrated in figure 6. The cap 34 and the collar 20 are lost at the bottom of the pile 74 formed by the settabte material.

In the examples which have been described, pile forming material is introduced into the ground as the probe is being withdrawn. Alternatively, pile forming material could be introduced into the gap 66, as the probe is being driven. Pile forming material may be introduced below the collar 20, as described, or above the collar 20, for example through an alternative mouth 30a (Fig. 1), located above the collar 20.

The example apparatus and example methods described above are expected to provide a number of practical advantages, such as the following. Skin friction between the probe 12 and the wall 64 is virtually eliminated, by the action of the collar 20, resulting in an expected reduction in the energy required to form a pile 74, and in the time required. Similarly, the probe 12 can easily be withdrawn, there being no interaction between the probe 12 and the oversize hole which has been formed.

During driving, the tapered region 32 and the pointed tip 16 may be beneficial in guiding the probe 12. In particular, it is envisaged that the elongate, pointed nature of the region 32 and tip 16 may assist in guiding the probe 12 through, past or between stones, rocks or other obstructions, It is envisaged that once the tip 16 has been forced into an appropriate path, such as a gap between two stones, there will be a reduction or removal of any tendency of the collar 20 to create a deflection of the probe 12 when encountering stones or rocks. It is envisaged that without the region 32 and tip 16, i.e. with a flat lower face to the arrangement, perpendicular to the axis 14, there may be an unacceptable tendency for the probe 12 to be deflected transversely when encountering an obstruction. This may prevent further penetration.

Many variations and modifications can be made to the apparatus described above, without departing from the scope of the present invention. In particular, many different shapes, sizes and relative shapes and sizes can be devised. In one example, the length of the probe 12 (along the axis 14) may be between 5m and 8m. The outside diameter of the probe 12 may be approximately 1.lm. The outside diameter of the collar 20 may be approximately 1.4m. This results in a clearance of approximately O.3m between the probe 12 and the wall 64, around the entire circumference.

Vibration and hammer driving techniques have been mentioned above, but any other suitable alternative driving technique could be used. Crowd or downward force may be applied to the probe 12, in addition to the driving force, particularly to overcome any resilient characteristics of local ground.

It is envisaged that the pile 74 may be used as a foundation pile, such as for house building or other purposes. Many other arrangements could be made for finishing the pile, particularly at the surface of the ground. This may include pile caps and arrangements for securing other structures to the pile. Reinforcements could be incorporated within the pile 74, such as metal mesh or bar inserted into the pile 74 before the pile material has set.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. Apparatus comprising: an elongate probe having an axis, a tip and an outline when viewed along the axis toward the tip, and an oversize portion having an outline, when viewed along the axis, toward the tip, which is further from the probe axis than the probe outline is from the probe axis, around at least part of the probe outline; wherein the probe extends beyond the oversize portion to the tip, and wherein, when the probe and the oversize portion are driven into the ground to form a hole in the ground, the probe engages the ground before the oversize portion I 5 engages the ground, and the oversize portion causes the outline of the hole wall to be spaced from the outline of the probe around at least said part of the probe outline.

2. Apparatus according to claim 1, wherein substantially the whole of the outline of the oversize portion is further from the probe axis than the probe outline is from the probe axis.

3. Apparatus according to claim 1 or 2, wherein the oversize portion is a collar carried by the probe.

4. Apparatus according to claim 3, wherein the collar is a planar member oriented substantially perpendicular to the probe axis.

5. Apparatus according to any preceding claim, comprising a mechanical coupling arrangement operable between the oversize portion and the probe to cause the oversize portion to be driven into the ground by movement of the probe.

6. Apparatus according to claim 5, wherein the mechanical coupling disengages when the probe is withdrawn, to leave the oversize portion in the ground.

7. Apparatus according to any preceding claim, wherein the leading end of the probe tapers to the tip. l0

8. Apparatus according to claim 7, wherein the tapered region lies between the tip and the position of the oversize portion when the probe is being driven.

9. Apparatus according to any preceding claim, wherein the tip is pointed.

10. Apparatus according to any preceding claim, further comprising a passage for a flowable medium and having at least one mouth through which the flowable medium can pass into the hole formed by the apparatus.

11 Apparatus according to claim 10, wherein the passage passes through the probe.

12. Apparatus according to claim 10 or 11, wherein the probe is hollow to provide the passage.

13. Apparatus according to any of claims 10 to 12, wheein the position of the oversize portion, when the probe is being driven, is further from the tip than the mouth or one of the mouths is from the tip.

14. Apparatus according to any of claims 10 to 13, wherein the or one of the mouths is at the tip.

15. Apparatus according to any of claims 10 to 14, wherein the, or one of the mouths, is further from the tip than the position of the oversize portion when the probe is being driven.

16. Apparatus according to any of claims 10 to 15, wherein the or each mouth is provided with a cover to prevent ingress of material while the probe is being driven.

17. Apparatus according to claim 16, wherein the cover is left in the ground as the probe is withdrawn.

18. A method for forming a hole for a foundation component in the ground, in which apparatus according to any of the preceding definitions is provided, the probe and oversize portion are driven into the ground to create a hole which has a hole wall spaced from the outline of the probe around at least part of the probe outline, and the probe is removed to leave a hole in the ground.

19. A method according to claim 18, wherein pile forming material is introduced into the hole as the probe is being withdrawn.

20. A method according to claim 18 or 19, wherein pile forming material is introduced into the hole as the probe is being driven.

21. Apparatus substantially as described above, with reference to the accompanying drawings.

22. A method substantially as described above, with reference to the accompanying drawings.