U.S. patent application number 17/416276 was filed with the patent office on 2022-02-10 for improvements in and relating to pile foundations.
The applicant listed for this patent is Keltbray Limited. Invention is credited to Stuart NORMAN, Paul Michael PELKEN.
Application Number | 20220042268 17/416276 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-10 |
United States Patent
Application |
20220042268 |
Kind Code |
A1 |
PELKEN; Paul Michael ; et
al. |
February 10, 2022 |
IMPROVEMENTS IN AND RELATING TO PILE FOUNDATIONS
Abstract
A pile (270) within a bore (110) comprises a column (250). The
column (250) comprises a stack of a plurality of pile sections
(300) arranged end-to-end within the bore (110). There is a cured
material (260) between at least a part of an outside surface of the
column (250) and the surface of the bore (110). The cured material,
for example grout, may be provided through channels in the pile
sections.
Inventors: |
PELKEN; Paul Michael; (Esher
Surrey, GB) ; NORMAN; Stuart; (Esher Surrey,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Keltbray Limited |
Esher Surrey |
|
GB |
|
|
Appl. No.: |
17/416276 |
Filed: |
December 18, 2019 |
PCT Filed: |
December 18, 2019 |
PCT NO: |
PCT/GB2019/053606 |
371 Date: |
June 18, 2021 |
International
Class: |
E02D 5/52 20060101
E02D005/52; E02D 7/00 20060101 E02D007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2018 |
GB |
1820764.7 |
Claims
1. A method of forming a pile within a bore, the method comprising:
stacking a plurality of hollow pile sections end-to-end within the
bore to form a column, there being a gap between at least a part of
an outside surface of the column and the surface of the bore;
filling the gap with a curable liquid material; and curing the
liquid material.
2. The method of claim 1, wherein the pile sections are tubular
pile sections, preferably having the same inner diameter.
3. The method of claim 1, further include the preceding step of
joining together a plurality of section components to form each
pile section.
4. The method of claim 1 wherein the curable liquid material is
grout.
5. The method of claim 1 including the step of pouring the curable
liquid material directly into the gap.
6. The method of claim 1, the method including the step of
directing the curable liquid material into the gap through channels
in the pile sections.
7. (canceled)
8. A pile within a bore, comprising: a column comprising a stack of
a plurality of hollow pile sections arranged end-to-end within the
bore, and a cured material between at least a part of an outside
surface of the column and the surface of the bore.
9. The pile within a bore of claim 8, wherein the column tapers in
width.
10. The pile within a bore of claim 8, wherein the pile sections
comprise elements at each of their axial ends, the axial end
elements being sized and shaped to interlock with the corresponding
axial end elements of another of the pile sections.
11. The pile within a bore of claim 8, wherein the pile sections
include channels configured to allow the transport of a curable
liquid material along the length of the column.
12. The pile within a bore of claim 8, wherein the pile sections
are pre-fabricated concrete.
13. (canceled)
14. The pile within a bore of claim 8, wherein the pile is
load-bearing within a building.
15. A kit of parts for forming a pile within a bore, the kit
comprising: a plurality of pile sections, wherein the plurality of
hollow pile sections are configured to be stacked end-to-end to
form a column, the number of pile sections corresponds to a length
of the column, said length being equal to at least half of the
depth of the bore; and a curable liquid material.
16. The method of claim 2, further including the preceding step of
joining together a plurality of section components to form each
pile section.
17. The method of claim 3, wherein the curable liquid material is
grout.
18. The method of claim 4, including the step of pouring the
curable liquid material directly into the gap.
19. The method of claim 5, the method including the step of
directing the curable liquid material into the gap through channels
in the pile sections.
20. The pile within a bore of claim 9, wherein the pile sections
comprise elements at each of their axial ends, the axial end
elements being sized and shaped to interlock with the corresponding
axial end elements of another of the pile sections.
21. The pile within a bore of claim 10, wherein the pile sections
include channels configured to allow the transport of a curable
liquid material along the length of the column.
22. The pile within a bore of claim 11, wherein the pile sections
are pre-fabricated concrete.
Description
FIELD OF THE INVENTION
[0001] The present invention concerns piles. More particularly, but
not exclusively, this invention concerns a pile within a bore and a
method and a kit of parts for forming the same. The invention also
concerns a building including a pile within a bore and a method of
forming the same.
BACKGROUND OF THE INVENTION
[0002] Piles are deep foundations providing support for buildings
or other structures. They are typically long, narrow columns of
reinforced concrete or steel. Prior-art piles include pre-cast
concrete piles that are driven into the ground using a pile-driver
and cast solid concrete piles that are formed by digging a bore in
the ground (typically using an auger), pouring concrete directly
into the hole and allowing it to set.
[0003] WO 2008/047151 A1 (City University) discloses a method of
forming a pile comprising: forming a bore in the ground to a
required depth; disposing a cylinder in the bore; filling the bore
with uncast concrete so that, on hardening, a cast concrete pile is
formed in the bore, the pile having a longitudinal cavity
permitting access to the pile along at least a portion of its
length. The longitudinal cavity is sufficiently wide to allow
access to the longitudinal cavity so that cast concrete can be
tested at a time after construction.
[0004] The approach in WO 2008/047151 can be relatively
time-consuming. There also is a risk that voids or other faults
will form in the pile when it is cast underground, as the bore in
which it is cast can have unpredictable or unhelpful wall
properties. Voids or other faults can result in weaknesses in the
cast concrete pile. Although the longitudinal cavity provides some
access for testing the cast concrete, there remains a risk that
faults go undetected.
[0005] The present invention seeks to mitigate the above-mentioned
problems.
SUMMARY OF THE INVENTION
[0006] A first aspect of the invention provides a method of forming
a pile within a bore, the method comprising:
[0007] stacking a plurality of hollow pile sections end-to-end
within the bore to form a column, there being a gap between at
least a part of an outside surface of the column and the surface of
the bore;
[0008] filling the gap with a curable liquid material ; and curing
the liquid material.
[0009] A second aspect of the invention provides a method of
constructing a building, the method including forming a pile within
a bore by the method of the first aspect of the invention.
[0010] A third aspect of the invention provides a pile within a
bore, the pile within a bore having the features set out in claim 8
below.
[0011] A fourth aspect of the invention provides a building
including a pile within a bore according to the third aspect of the
invention.
[0012] A fifth aspect of the invention provides a kit of parts
having the features set out in claim 15 below.
[0013] It will of course be appreciated that features described in
relation to one aspect of the present disclosure may be
incorporated into other aspects of the present disclosure. For
example, the method of the present disclosure may incorporate any
of the features described with reference to the apparatus of the
present disclosure and vice versa.
DESCRIPTION OF THE DRAWINGS
[0014] Embodiments of the present disclosure will now be described
by way of example only with reference to the accompanying schematic
drawings of which:
[0015] FIGS. 1a to 1h are a sequence of side views of a pile being
formed, according to a first embodiment of the present
disclosure;
[0016] FIG. 2 is a perspective view of a pile section according to
a second embodiment of the present disclosure;
[0017] FIG. 3 is a perspective view of a pile section according to
a third embodiment of the present disclosure;
[0018] FIG. 4 is a perspective view of a pile section according to
a fourth embodiment of the present disclosure;
[0019] FIG. 5 is a side view of a pair of pile sections according
to a fifth embodiment of the present disclosure;
[0020] FIG. 6 is a plan view of a pile section according to a sixth
embodiment of the present disclosure; and
[0021] FIG. 7 is a plan view of a pile section according to a
seventh embodiment of the present disclosure;
DETAILED DESCRIPTION
[0022] A first aspect of the invention provides a method of forming
a pile within a bore, the method comprising: [0023] stacking a
plurality of hollow pile sections end-to-end within the bore to
form [0024] a column, [0025] there being a gap between at least a
part of an outside surface of the column and the surface of the
bore; [0026] filling the gap with a curable liquid material; and
[0027] curing the liquid material. [0028] The pile sections may be
tubular pile sections; thus, the column may be a tube.
[0029] The pile sections are preferably concrete. The pile sections
are preferably pre-formed (for example pre-cast) at a location
remote from the location at which the pile is to be formed. The
method may comprise the step of receiving the pile sections from a
remote location.
[0030] The surface of the bore will be understood to be the surface
of the surrounding soil into which the bore is made (typically
longitudinally and circumferentially extending).
[0031] The method may include the step of joining together a
plurality of section components to form each pile section. The
section components are preferably pre-formed (for example pre-cast)
at a location remote from the location at which the pile is to be
formed. The method may comprise the step of receiving the plurality
of section components from a remote location, and then joining
together the plurality of section components to form each pile
section.
[0032] The curable liquid, when in place and cured, is preferably
configured to transfer the skin friction generated at the interface
with the pile bore to the interface between the grout and the
sections of the pile.
[0033] The curable liquid material may be grout. The grout may
comprise reinforcing material. Alternatively, the curable liquid
material may be for example resin.
[0034] Advantageously, grout is not concrete. Providing a pile
formed from a stack of pile sections and then filling the gap
between the pile and the bore, with the curable liquid, has been
found to be especially advantageous because it tends to be possible
to use on a variety of soil types (whereas the pile in WO
2008/047151 tends to be limited to use of clay soils).
[0035] The method may include the step of pouring the curable
liquid material directly into the gap. The curable liquid material
may be inserted under relatively low pressure.
[0036] The method may comprise the step of applying additional
curable liquid material after the previous liquid material has
cured. The additional curable liquid material may be supplied at
relatively high pressure, for example such that it cracks and
percolates through the first cured material. This step may be
advantageous on fine soils as it enables the additional curable
liquid to percolate into the soil. The additional curable liquid
material may be grout, preferably finer grout than the first
curable liquid material.
[0037] The method may include the step of directing the curable
liquid material into the gap through channels in the sections. The
stacking may include aligning the channels of one section with the
channels of an adjacent section, such that the liquid material may
flow from the channel in one section to the channel in an adjacent
section. Alignment may be achieved visually but is more preferably
achieved via an alignment arrangement (such as interlocking male
and female members located at a common location on the opposing
ends of the adjacent pile sections). The adjacent pile sections may
be configured to be self-aligning (for example they may comprise
suitable inclined surfaces to ensure correct alignment as the
adjacent sections are stacked together).
[0038] The method may include the step of digging the bore, for
example using an auger.
[0039] The method may include the step of forming impressions into
the interior wall of the bore.
[0040] The method may include lowering the pile sections into the
bore sequentially, for example one-at-a-time.
[0041] The column may have a length that is substantially the same
as the depth of the bore. The column may be shorter than the depth
of the bore. The column may for example have a length that is
between half the depth of the bore, and the full depth of the bore.
Alternatively, the column may be longer than the depth of the
bore.
[0042] The column may have a length that is more than three times
its breadth. The gap may be continuous. The gap may extend across
the majority, (preferably, all or substantially all) of the outside
surface of the column and the surface of the bore. The gap may be
substantially uniform around the outside surface of the column.
[0043] The curable liquid material may fill all or substantially
all of the gap. The method may comprise the step of installing a
pile cap on the top of the final pile section to close off the top
of the stack of pile sections. The method may comprise the step of
selecting the pile cap from a plurality of differently-sized (more
preferably different length) pile caps. The pile caps may be
pre-cast. This may ensure the correct height of the pile may be
obtained (for example a relatively short cap can be provided if the
stack of pile sections is relatively tall in the bore, and likewise
a relatively long cap can be provided if the stack of pile sections
is relatively short in the bore).
[0044] Before placing the stack of pile sections into the bore, the
method may comprise the step of initially installing a pile base
piece in the base of the bore, to close off the base of the pile.
The pile base piece may facilitate increased end bearing resistance
of the pile. The pile base piece may be shaped to facilitate
increased end bearing resistance of the pile.
[0045] A second aspect of the invention provides a method of
constructing a building, the method including forming a pile within
a bore by the above-mentioned method. A third aspect of the
invention provides a pile within a bore, comprising:
[0046] a column comprising a stack of a plurality of pile sections
arranged end-to-end within the bore, and a cured material between
at least a part of an outside surface of the column and the surface
of the bore.
[0047] The plurality of pile sections may include pile sections
that have different widths from each other. The column may taper in
width, for example so that it has a smaller width at its base and a
larger width at its top (or vice versa). Thus, the pile sections
forming the column may increase in width with height up the column
(or vice versa). The pile sections may have the same internal width
(e.g. internal diameter). A taper in the column may be achieved by
varying the thickness of the wall of adjacent pile sections. In
embodiments comprising a channel configured to allow the transport
of a curable liquid material along the length of the column, a
channel in each pile section may be at the same spacing (e.g.
radius) from the centre of the column. That spacing may be defined
by the smallest width pile section.
[0048] The pile sections may be tubes. The tubes may have a
constant inner width along the height of the column (even in
embodiments in which the outer width of the tubes is not the same
along the height of the column, for example where the tubes forming
the column increase in width with height up the column). The tubes
may have an internal width that is at least half their external
width.
[0049] The pile sections may be circular in cross-section. The pile
sections may be polygonal in cross-section.
[0050] The pile sections may comprise elements (for example
castellations) at each of their axial ends, the axial end elements
being sized and shaped to interlock with the corresponding axial
end elements of another of the pile sections.
[0051] The pile sections may comprise a plurality of section
components. Each pile section may for example be made from between
2 and 10 section components. The plurality of section components
may be identical to each other. The section components may be
segments of an annulus. Providing section components in each pile
section may facilitate efficient transport of the components of the
pile (compared to transporting fully assembled, or cast, pile
sections).
[0052] Each pile section, and preferably each pile section
component, may comprise elements (for example, tongue-and-groove
elements) at each axial end, sized and shaped to interlock with the
corresponding elements of another of the pile section/pile section
component. The method may comprise the step of joining adjacent
pile sections together, for example with a fastener.
[0053] At least some of the pile sections may include a raised
and/or indented pattern on their outer surfaces, i.e. a textured
pattern. The pattern may be irregular.
[0054] Alternatively, the pattern may be a regular pattern of
repeating shapes. Such an arrangement may facilitate effective
binding of the curable liquid to the outer surface of the sections
and/or increase the resistance between the outer surface of the
pile and the cured liquid. At least some of the sections may
include protrusions on their outer surface, which may be arranged
in a regular pattern. The protrusions may be dome-shaped.
[0055] At least some of the sections may include channels
configured to allow the transport of a curable liquid material
along the length of the column. The channels may be within the
sections, for example entirely enclosed in the solid material of
the sections (save at inlets and outlets). The channels may be
wholly or partly on the surface of the sections, for example the
channels may be exposed channels running along a face of the
sections. The channels may comprise transport channels in fluid
communication with outlet channels. The transport channels may be
vertical. The outlet channels may be horizontal. The transport
channels may be in fluid communication with the outlet channels.
There may, for example, be a multiplicity, for example 1 to 10,
transport channels in each pile section. The transport channels may
be at the same radial position in each pile section in the
column.
[0056] The hollow pile sections may be concrete, for example
pre-cast concrete. Use of pre-cast concrete has the advantage that
the pile sections (or the section components) can be manufactured
remotely from the site of the bore and then transported to the bore
for use. Manufacturing the pile sections (or the section
components) as pre-cast concrete, before their use in the bore, has
the advantage that quality checks can be carried out on them before
their installation in the ground. The pile sections may be
reinforced concrete.
[0057] A fourth aspect of the invention provides a building
including a pile within a bore, as described herein. The pile may
be load-bearing within the building.
[0058] A fifth aspect of the invention provides a kit of parts for
forming a pile within a bore, the kit comprising:
[0059] a plurality of pile sections, wherein [0060] the plurality
of pile sections are configured to be stacked end-to-end to form a
column, [0061] the number of pile sections corresponds to a length
of the column, said [0062] length being equal to at least half of
the depth of the bore; and
[0063] a curable liquid material.
[0064] The invention will now be more fully understood and further
advantages will become apparent when reference is made to the
following detailed description of embodiments of the invention,
wherein like reference numerals denote similar elements.
[0065] FIG. 1a to 1h show in side view an example embodiment of the
method of forming a pile. In FIG. 1a, bore 110 has been excavated
in the ground 10 using an auger (not shown), which has been
operated by piling rig 100. Piling rig 100 includes attachment
point 102 that is used to attach various apparatus that is to be
lowered into bore 110. (For example, the auger was attached to
attachment point 102 during the digging of the bore 110).
[0066] In FIG. 1b, impression-forming attachment 104 is attached to
attachment point 102 and is lowered into bore 110.
Impression-forming attachment 104 comprises a plurality of
impression-forming elements 106 that are configured to form
impressions in the interior wall of bore 110 when
impression-forming attachment 104 is actuated to expand outwards in
a radial direction. The actuation and expansion of impression
forming attachment 104 is shown in FIG. 1c. Impression forming
elements 106 are pressed into the wall of bore 110 to form
impressions 112. Impression forming attachment 104 is then
withdrawn from bore 110 by piling rig 100 as shown in FIG. 1d. The
result of this operation as shown in FIGS. 1b to 1d is that
impressions 112 are formed in the wall of bore 110.
[0067] An advantageous effect of impressions 112 is that when the
pile is finally constructed, the skin friction between the pile and
the bore is increased, thereby increasing the pull-out resistance
and/or providing a piling structure that better reacts loads into
the ground. However, this feature is not essential to the invention
and in alternative embodiments of the present disclosure, the steps
of FIGS. 1b to 1d may be omitted, and substantially no impressions
are formed in the wall of bore 110.
[0068] In FIG. 1e, pile section 200a has been attached to
attachment point 102. Pile section 200a is a hollow cylinder of
prefabricated concrete. Piling rig 100 lowers pile section 200a
into bore 110 as indicated by directional arrow 105.
[0069] Successive pile sections 200b, 200c, 200d, 200e are attached
to attachment point 102 and lowered into bore 110 respectively in
turn. As shown in FIG. 1f, each successive pile section is stacked
on top of the previous section to form vertical column 250. Dashed
line 202 indicated the continuous inner surface of hollow column
250. The size of pile sections 200a-200e is selected such that when
pile sections 200a-200e are stacked to form column 250, there is a
gap 114 between the outer surface of column 250 and the inner
surface of bore 110. While column 250 has a length that is
substantially the same as the height of bore 110, in alternative
embodiments of the present disclosure column 250 may have a length
that is shorter than the height of the bore, for example, to leave
some space at the top of bore 110 for other structural features in
the construction. Indeed, the length of column 250 may correspond
to between half the height of bore 110, and the full height of bore
110. In alternative embodiments of the present disclosure, the
length of column 250 may correspond to a height greater than the
height of bore 110.
[0070] FIG. 1g shows that grout 260 is poured into gap 114. The
insertion of grout 260 is indicated by directional arrow 113.
[0071] FIG. 1h shows that grout 260 has filled gap 114, including
impressions 112 within the wall of bore 110. This forms completed
pile 270. In alternative embodiments of the present disclosure,
grout 260 may be an alternative curable liquid material, for
example a resin. An advantage of grout is that it is light and
cheap, and has relatively low viscosity (compared to more coarse
materials such as concrete).
[0072] Column 250 is formed of concrete and can bear the majority
of the primary longitudinal loads from any construction above. The
grout is arranged to transfer the skin friction generated at the
interface with the pile bore to the interface between the grout and
the pre-cast sections of the pile (i.e. such that the loads can be
reacted/transferred from the pile to the surrounding soil).
[0073] In alternative embodiments of the present disclosure, pile
sections 200a-200e may comprise channels. Grout 260 is poured into
the channels within column 250 to achieve a uniform distribution of
grout 260 across the entire length of column 250. For example, FIG.
2 shows a perspective view of pile section 300 according to an
embodiment of the present disclosure. Pile section 300 comprises
vertical channels 302 in fluid communication with horizontal
channels 304 (shown in dashed lines in FIG. 2). Vertical channels
302 are designed to allow for a vertical flow of curable liquid
material through section 300. Horizontal channels 304 allow for the
curable liquid material to flow out of pile section 300. In
embodiments of the present disclosure, the curable liquid material
would flow out of horizontal channels 304 and into a gap (such as
gap 114 in the embodiments of FIGS. 1a-1e).
[0074] In alternative embodiments of the present disclosure,
vertical channel 302 is not entirely enclosed in the solid material
of pile section 300. Instead vertical channel 302 may be an exposed
channel running along the outside face of pile section 300.
[0075] FIG. 3 shows a perspective view of pile section 400
according to an embodiment of the present disclosure. Pile section
400 comprises textured pattern 402 on its exterior surface.
Textured pattern 402 comprises protrusions that extend outwardly
from the surface of pile section 400. These protrusions have the
effects of increasing the friction between the outer surface of
pile section 400 and any grout that may be in contact with it (such
as grout 260 in the embodiments of FIGS. 1a-1h). In embodiments of
the present disclosure, textured pattern 402 may be irregular. In
embodiments of the present disclosure, textured pattern 402 may be
a regular pattern of repeating shapes.
[0076] FIG. 4 shows a perspective view of pile section 500
according to an embodiment of the present disclosure. Pile section
500 comprises regular, circular-shaped protrusions 502 at regular
intervals around the outer surface of pile section 500. The
function of protrusions 502 are similar to the function of textured
pattern 402 in the embodiment of FIG. 3. In alternative embodiments
of the present disclosure, protrusions 502 may be non-circular but
may for example be any other regular shape, such as an oval, or
square.
[0077] FIG. 5 shows a side view of a pair of pile sections 600a,
600b according to an embodiment of the present disclosure. Each
pile section 600a, 600b comprises a castellations at an axial end.
The castellations of first pile section 600a are sized and shaped
to interlock with the castellations of second pile section 600b.
This is achieved by the provision of female alignment portion 602a,
and the provision of male alignment portion 602b. When first pile
section 600a is brought together with second pile section 600b, the
respective alignment portions fit within one another and prevents
pile sections 600a, 600b from experiencing any radial or
circumferential displacement. Advantageously, in embodiments in
which pile sections 600a, 600b comprise channels (such as those of
FIG. 2), the castellations enable a more straightforward alignment
of the vertical channels of adjoining pile sections.
[0078] FIG. 6 shows a plan view of pile section 700 according to an
embodiment of the present disclosure. Pile section 700 is composed
of three equally sized pre-cast concrete section components 702,
704, 706. When the section components 702, 704, 706 are assembled
together, they form a concrete cylinder that is pile section 700.
To facilitate alignment, each section component comprises
protrusion 702b and recess 702a at each end. Protrusion 702b
interlocks with recess 704b of adjacent pile section 704. Likewise,
recess 702a interlocks with protrusion 704a of the same adjacent
pile section 704. The protrusions and recesses ensure that once the
pile sections are in position, the pile sections are only free to
move in an axial direction, and are fully restricted in the radial
and circumferential directions. Assembling the pile section from a
plurality of section components allows the pile sections to be
readily transported (as section components, that can typically be
stacked or otherwise efficiently stored).
[0079] FIG. 7 shows a plan view of pile section 800 according to an
embodiment of the present disclosure. Pile section 800 is composed
of five equally sized pre-cast concrete section components 802,
804, 806, 808, and 810. When the section components 802, 804, 806,
808, and 810 are assembled together, they form a hollow concrete
pentagon that is pile section 800.
[0080] Whilst the present invention has been described and
illustrated with reference to particular embodiments, it will be
appreciated by those of ordinary skill in the art that the
invention lends itself to many different variations not
specifically illustrated herein. By way of example only, the pile
sections need not necessarily be circular cylindrical. The pile
sections may be other shapes such as polygonal. It may be that the
section components of the pile sections are configured such that
they can form different shaped/sized polygonal sections by altering
the angle of the join between adjacent section components and/or by
choosing differently sized section components.
[0081] Where in the foregoing description, integers or elements are
mentioned which have known, obvious or foreseeable equivalents,
then such equivalents are herein incorporated as if individually
set forth. Reference should be made to the claims for determining
the true scope of the present invention, which should be construed
so as to encompass any such equivalents. It will also be
appreciated by the reader that integers or features of the
invention that are described as preferable, advantageous,
convenient or the like are optional and do not limit the scope of
the independent claims. Moreover, it is to be understood that such
optional integers or features, whilst of possible benefit in some
embodiments of the invention, may not be desirable, and may
therefore be absent, in other embodiments.
* * * * *