NOVEL SYSTEM AND METHOD FOR INSTALLING GROUT-FILLED FRICTION PILES
20230089034 · 2023-03-23
Inventors
Cpc classification
E02D5/54
FIXED CONSTRUCTIONS
International classification
Abstract
The friction pile system may include a steel pipe column, an auger spiraled around its exterior surface, a helical plate near the tip, and small structural elements located around the helix. A plurality of perforations may be provided on the pipe wall. The method of installation includes screwing the pipe assembly down into the ground by rotating it with a drivehead and simultaneously pressure injecting cement grout inside the pipe. The structural elements including weld beads maintain the bore hole created by the rotating helix and also guide grout to flow out though the perforations and upward along the auger while spreading outward filling in the hole. Thus the engineered pipe assembly leverages the mechanical energy of drilling to pressurize grout upward and outward improving bond with soil yielding high pile capacity.
Claims
1. A novel grout-filled friction pile system, comprising: a hollow column having an interior comprising a centrally disposed longitudinal axis extending in a longitudinal direction from a driving end to a closed end, the column having an outside surface, an inside surface, and a first width extending in a lateral direction perpendicular to the longitudinal direction; an auger portion disposed on the outside surface of the column and comprising a first helical pattern fanning out in the lateral direction, the auger portion extending in the longitudinal direction along the outside surface of the column towards the top end; and a plurality of perforations selectively disposed along the column and penetrating the outside surface and inside surface, the plurality of perforations configured to provide a passageway for supplying cementitious material from the interior of the column through the outside surface as excreted cementitious material, wherein the auger portion is configured to convey the excreted cementitious material towards the top end upon rotation of the column around the longitudinal axis.
2. The friction pile system of claim 1, further comprising a capping portion disposed at a tip of the driving end and including a surface that substantially closes the driving end.
3. The friction pile system of claim 2, comprising: a helix portion disposed on the outside surface of the column proximate the driving end and comprising a second helical pattern configured to drill the column downward into the ground upon rotation of the column around the longitudinal axis, and wherein the auger portion is disposed at an elevation that is above the helix portion.
4. The friction pile system of claim 3, wherein an outside edge of the helix portion extends a first distance from the outside surface of the column in the lateral direction and an outside edge of the auger portion extends a second distance from the outside surface of the column in the lateral direction, the first distance being greater than the second distance.
5. The friction pile system of claim 3, wherein the auger portion comprises a first pitch and the helical portion comprises a second pitch, the first pitch being greater than the second pitch.
6. The friction pile system of claim 5, wherein the first pitch is about twice that of the second pitch.
7. The friction pile system of claim 1, further comprising a plurality of structural elements disposed on the outside surface of the column, wherein at least one structural element of the plurality of structural elements is disposed proximate a corresponding perforation of the plurality of perforations, and wherein at least one structural element of the plurality of structural elements is configured to push the excreted cementitious material away from the outside surface of the column during rotation of the column.
8. The friction pile system of claim 1, further comprising a plurality of structural elements disposed on the outside surface of the column, at least one structural element of the plurality of structural elements is disposed proximate a corresponding perforation of the plurality of perforations and configured to protect the perforation during rotation of the column.
9. The friction pile system of claim 8, further comprising: a helix portion disposed on the outside surface of the column proximate the driving end and comprising a second helical pattern configured to drill the column downward into the ground upon rotation of the column around the longitudinal axis, and wherein the plurality of perforations includes a first perforation disposed proximate the helix portion.
10. The friction pile system of claim 9, wherein the first perforation comprises a reinforced weep hole.
11. The friction pile system of claim 1, wherein the interior of the column is configured to be substantially filled with the cementitious material.
12. The friction pile system of claim 11, wherein the outside of the column is configured to be substantially surrounded by the conveyed excreted cementitious material.
13. The friction pile system of claim 1, further comprising a plurality of reinforcement angles disposed on the outside surface, each reinforcement angle of the plurality of reinforcement angles extending in the longitudinal direction between a corresponding top surface of the helix pattern to a corresponding bottom surface of the auger pattern.
14. The friction pile system of claim 13, wherein each reinforcement angle of the plurality of reinforcement angles extends laterally from the outside surface in the lateral direction.
15. A method for installing a friction pile system, comprising: providing a pipe assembly system, comprising: a hollow column extending in a longitudinal direction and having a substantially closed end, the column defining a centrally disposed longitudinal axis extending in the longitudinal direction, the column including an outside surface and an inside surface, a helix portion and an auger portion extending along the outside surface of the column from a lower elevation of the column to an upper elevation of the column, and a plurality of perforations, the plurality of perforations including a first perforation disposed proximate the lower elevation of the column and penetrating the outside surface and inside surface of the column, injecting cementitious material under pressure into an interior of the column through an upper end of the hollow column; excreting the cementitious material from the interior of the column through the first perforation; rotating the pipe assembly system; and conveying the excreted cementitious material along the auger portion from the lower elevation to the upper elevation.
16. The method of claim 15, wherein: the friction pile system further comprises a plurality of V-shaped gussets disposed on the outside surface of the column and extending laterally from the outside surface of the column, each V-shaped gusset being disposed proximate an elevation of a corresponding perforation of the plurality of perforations.
17. The method of claim 16, further comprising: pushing the excreted cementitious material away from the outside surface of the column via the plurality of v-shaped gussets, and wherein at least a portion or an entirety of each of the rotating step, the grout injecting step, the conveying step, and the pushing step is performed simultaneously.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0007]
[0008]
[0009]
[0010]
[0011]
[0012]
DETAILED DESCRIPTION OF PILE
[0013] The following discussion omits or only briefly describes certain components, features and functionality related to one type of friction piles also called micropiles and related methods of installing these friction piles, which are apparent to those of ordinary skill in the art. It is noted that various embodiments are described in detail with reference to the drawings, in which like reference numerals represent like parts and assemblies throughout the several views, where possible. Reference to various embodiments does not limit the scope of the claims appended hereto because the embodiments are examples of the inventive concepts described herein. Any example(s) set forth in this specification are intended to be non-limiting and set forth some of the many possible embodiments applicable to the appended claims. The particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations unless the context clearly indicates otherwise.
[0014] Referring generally to
[0015] The interior void space may define a centrally disposed longitudinal axis L-A extending in the longitudinal direction from a top end 101 to a bottom end 102. The top end 101 of body 10 may be configured for connecting to a rotary driver machine configured to rotate the pipe assembly 100, for example. Additionally, the top end 101 may comprise an open end, or at least a partially open end granting access to the interior void space of the body 10. A bottom-most surface of the bottom end 102 may comprise a closed end preventing access to the interior void space of the body 10 (or at least a substantially closed end). The body 10 may have a width that extends in a lateral direction (represented by X direction in the labeled coordinate system) through the body 10 and passing through the longitudinal axis L-A. The width of body 10 may be any size depending on the particular structural load bearing requirements. In various embodiments, the longitudinal direction and lateral direction may be perpendicular to one another.
[0016] The bottom end 102 may include a capping portion 16, for example. In various embodiments, the capping portion 16 comprises a steel plate having a planar outside surface that is welded to the bottom-most surface of the body 10, e.g., a continuous fillet weld, etc. that is suitable for the thickness of the steel plate and body 10. Additionally, the capping portion 16 may be flush with the outside surface of the body 10. Furthermore, the capping portion 16 may be angled with respect to the body 10 and/or longitudinal axis L-A at about 25 degrees to about 65 degrees, about 35 degrees to about 55 degrees, or in some embodiments about 45 degrees, terminating in a peak that extends from the body 10 in the direction of the longitudinal dimension. The capping portion 16 may be configured to loosen and/or scratch the ground and push debris laterally to the side while the pipe assembly 100 is being rotated. In some embodiments, (not illustrated) a boring machine may initially drive a relatively narrow pilot hole for guiding the cutting portion 16 into the ground; although, in other embodiments a pilot hole is not necessary.
[0017] In various embodiments, a helix portion 12 may be disposed adjacent the capping portion 16 proximate the bottom portion 102. The helix portion 12 may be disposed on the outside surface of the body 10 and have a geometry that is defined by a first helical pattern fanning out from the body 10 in the lateral direction. For example, the first helical pattern may spiral along the outside surface of the body 10 and have about a 4 inch to 8 inch pitch, and in some embodiments about a 6 inch pitch. In the illustrated embodiment, the helix portion 12 makes about one full revolution about the outside surface of body 10 although in other embodiments the helix portion 12 may be repeated with additional plates and/or make additional revolutions around body 10. In various embodiments, the helix portion 12 may be welded to the outside surface of body 10 by, e.g., a thick and continuous fillet weld of about ¼ an inch (quarter of an inch) to about ½ an inch (half of an inch). Additionally, and when viewed as a section cut in plan view (see
[0018] Pipe assembly 100 may further include an auger portion 14 disposed on the outside surface of the body 10 that spirals upward along the body 10 between the helix portion 12 and the top end 101. In some embodiments, the auger portion 14 may begin at an elevation that is proximate to the upper most portion of the helix portion 12, for example. In other embodiments, the auger portion 14 may begin at an elevation that is farther away from helix portion 12 and in other embodiments still auger portion 14 may terminate and/or pick up where helix portion 12 terminates. Auger portion 14 may have a geometry that is defined by a second helical pattern fanning out from the body 10 in the lateral direction. The second helical pattern may be different than the first helical pattern. For example, the auger portion 14 may spiral along the outside surface of the body 10 and have about a 8 inch to 16 inch pitch or in some embodiments about a 12 inch pitch. In at least one embodiment, the pitch of the auger portion 14 is about twice that of the helix portion 12. The auger portion 14 may spiral along the outside of the body 10 from an elevation proximate the helix portion 12 to the top end 101. The auger portion 14 may be formed by cutting from a wide steel plate, bending it according to the design criteria, and welding it the outside surface of body 10.
[0019] Auger portion 14 may further be functionally supported by a plurality of angles and/or other structural elements 18. Structural elements 18 may comprise a closed L-shaped gusset or flange or a V-shaped gusset or a flange that is disposed on the outside surface of the body 10. For example, both outside surfaces of a 90 degree L-shaped gusset may face away from body 10 and the inside surfaces that form a 90 degree bend face the outside surface of body 10. For example still, the outside notch of the L-shaped gusset may point away from body 10 as illustrated in
[0020] Pipe assembly 100 may further include at least one perforation 19. In the example embodiment, pipe assembly 100 may include a plurality of perforations 19 selectively disposed along the body 10 at discrete locations. Each perforation 19 may penetrate the outside surface and inside surface of body 10. In various embodiments, perforations 19 may take any suitable shape, e.g., a circular hole (weep hole), an oblong hole, a slit extending in the longitudinal direction, a slit extending in the lateral direction, and/or an angled slit extending in a direction that is angled with respect to the longitudinal direction. In the embodiment of
[0021] In various embodiments, perforations 19 may be configured to provide a passageway for supplying cementitious material from the interior of the body 10 through the outside surface of body 10 as excreted cementitious material. For example, cementitious material may be injected into the interior of body 10 at the top end 101 by any known means such as a swivel system. In some embodiments, cementitious material such as a flowable grout may be injected into the interior of body 10 under pressure, also referred to in the art as pressure injection grouting. The pressure applied may be in the range of 50-200 psi and substantially constant as the pipe assembly 100 is drilled further into the ground. In turn, the interior of the body 10 may become filled with cementitious material and the cementitious material may flow from the interior of the body 10 through the perforations 19 and to the outside of the body 10. The cementitious material may flow to the outside of the body 10 due to gravity forces initially and then being pressure injected.
[0022] In some embodiments, the cementitious material may be injected into the interior of the body 10 while the pipe assembly 100 is being inserted into the ground by rotation. For example, at least a portion of the rotation and insertion of the pipe assembly 100 and the pressure injection grouting may be performed simultaneously. In some embodiments, cementitious material may continue to be injected into the interior of body 10 after pipe assembly 100 has reached some or the entirety of the target depth. In other embodiments, the cementitious material may be injected in whole or in part after the pipe assembly 100 has been drilled into the ground and reached its target depth. In various embodiments, a target depth may correspond to an elevation where the depth through the competent soil layer is considered sufficient for the design pile capacity, for example. In some embodiments, the pipe assembly may reach the bedrock.
[0023] Consistent with the disclosure herein, the excreted cementitious material will surround the outside of the body 10 due to flowing through penetrations 19, for example. The cementitious material will initially flow through a perforation 19 at the lowest elevation and thereafter will flow through perforations 19 at higher elevations until the cementitious material fills the interior of body 10 and the surrounding space around the pipe assembly 100, i.e. the bore hole and void spaces in the surrounding ground. In various embodiments, perforations 19 may be disposed along the outside of body 10 at regularly spaced elevations from the closed bottom end 102 to the top end 101 or the perforations 19 may be selectively disposed along the outside of body 10 at various elevations configured to facilitate the dispersal of the cementitious material around the body 10. For example,
[0024] This arrangement is particularly advantageous because gravity fed grout may be insufficient, on its own, to force the cementitious material through perforations 19 and upwards to fill the whole cavity (bore hole) surrounding the pipe assembly 100. Notably, embodiments in accordance with the pressurization principles of this disclosure provide a plurality of selectively disposed perforations 19 that feed cementitious material to the helix portion 12 and auger portion 14 such that the helical pattern 11, including the helix portion 12 and auger portion 14, conveys the excreted cementitious material upwards and facilitates even dispersal of the cementitious material around the outside of body 10.
[0025]
[0026] In this way, embodiments in accordance with the principles of this disclosure provide for a pipe assembly 100 that is configured to convey cementitious material vertically along the outside of body 10 in the longitudinal direction and force cementitious material into the available pore space in the surrounding soil or strata. The pipe assembly 100 is engineered in a way that the mechanical energy of drilling the pipe downward will be leveraged to guide and push the grout upward along the auger to fill the bore hole. For example, the rotation of pipe assembly 100 may guide and push the grout upward along the auger 14 to fill the bore hole. In addition to assisting upward movement of grout, the external pressure will push the grout laterally outward thereby penetrating soil and improving a bond between the soil and grout column. This configuration facilitates the even dispersal of the cementitious material throughout the inside of body 10 and throughout the outside of body 10. Once the pipe assembly 100 has been drilled to a sufficient depth, and the interior of the body 10 will not receive any more cementitious material, rotation of the pipe assembly 100 may be stopped and the cementitious material may be allowed to cure and/or harden. Because the cementitious material is substantially homogenously dispersed on the outside of body 10, in the interior of body 10, and is forced into the surrounding ground at pressure, the disclosed friction pile system 110 provides for a strong load bearing system in both the vertical direction and in the lateral direction in a cost effective manner.
[0027] In some embodiments, it is impractical to provide a single pipe assembly 100 of a length that can reach a target design depth. Accordingly, multiple pipe assemblies 100 that are the same as, substantially the same as, and/or similar to pipe assembly 100 may be connected together at a construction site to provide for a final friction pile system 110 having an appropriate length to reach a target design depth. For example, multiple pipe assemblies 100 may be “spliced” together.
[0028]
[0029] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. For example, features, functionality, and components from one embodiment may be combined with another embodiment and vice versa unless the context clearly indicates otherwise. Similarly, features, functionality, and components may be omitted unless the context clearly indicates otherwise. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques).
[0030] Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc. It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified, and that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.