Helical pile

Abstract

The present invention relates to a helical pile for being inserted into the ground. The helical pile includes a helical blade and a cylindrically shaped wall extending outwardly of the helical blade. The helical blade and / or the cylindrical wall includes one or more selected from an aperture and a recess. The aperture and a recess may extend from the cylindrical wall into the helical blade. The cylindrical wall may extend upwardly from the periphery of the helical blade, and / or it may extend downwardly from the periphery of the helical blade. A helical flange may extend outwardly of the cylindrical wall. The thickness of the cylindrically shaped wall may vary over the length of the cylindrically shaped wall.

Description

HELICAL PILEField of the Invention

[0001] The present invention relates to a helical pile and in particular to a helical screw pile for use as shallow or deep pile foundations.

[0002] The invention has been developed primarily for use in / with foundations and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.Background of the Invention

[0003] At present helical piles have become one of the most commonly employed approaches for a variety of structures. Helical piles foundation technology entails affixing a steel foundation to at least one helical bearing plate that is attached to a rotating shaft in the ground.

[0004] The advantages of helical piles over other piling technologies include installation ease, low noise and vibration levels, low cost, and high bearing capacity.

[0005] The helical pile installation process involves coupling the helical pile's shaft to a hydraulic torque engine and rotating the helical pile in the ground using torque and vertical downward pressure. Helical piles are designed to withstand multiple forms of loads (compression, tension, and lateral).

[0006] Any discussion of the background art throughout the specification should in no way be considered as an admission that such background art is prior art, nor that such background art is widely known or forms part of the common general knowledge in the field in Australia or any other country.Summary of the Invention

[0007] The invention seeks to provide a helical pile which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[0008] In a discussion of the relative directions below, the words “upwards” and “downwards” are to be construed as corresponding to the directions in which the helical pile would be inserted into the ground.

[0009] According to a first aspect, the present invention may be said to involve a helical pile for being inserted into the ground, the helical pile including:a. a helical blade;b. a cylindrically shaped wall extending outwardly of the helical blade; c. wherein the helical blade includes one or more selected from an aperture and a recess in the helical blade.

[0010] In one embodiment, the one or more selected from an aperture and a recess extends into the cylindrically shaped wall.

[0011] In one embodiment, the cylindrically shaped wall includes one or more selected from an aperture and a recess in the cylindrically shaped wall.

[0012] In one embodiment, the one or more selected from an aperture and a recess extends downwardly from the helical blade on the cylindrically shaped wall.

[0013] In one embodiment, the thickness of the cylindrically shaped wall varies over the length of the cylindrically shaped wall.

[0014] In one embodiment, the thickness of the cylindrically shaped wall tapers between a smaller thickness towards the lower half and a larger thickness towards the upper half.

[0015] In one embodiment, the helical blade extends 360° around its axis.

[0016] In one embodiment, the helical pile includes a central shaft that extends along the axis of the helical blade.

[0017] In one embodiment, the cylindrically shaped wall extends downwardly from an outer edge of the helical blade.

[0018] In one embodiment, the cylindrically shaped wall extends upwardly from an outer edge of the helical blade.

[0019] In one embodiment, the helical blade can include a cutting edge at a lower end.

[0020] In one embodiment, the cutting edge is one or more selected froma. tapered;b. cone-shaped;c. flat ended.

[0021] In one embodiment, the length of the cylindrically shaped wall is between 1 and 10 times the pitch of the helix.

[0022] More preferably, the length of the cylindrically shaped wall is between 1 and 4 times the pitch of the helix.

[0023] In one embodiment, the aperture is between 1% and 10% of the surface area of the helical blade.

[0024] In one embodiment, at least one edge of the aperture in the helical blade extends from the helical surface of the helical blade.

[0025] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the helical blade extends upwardly from the helical surface of the helical blade.

[0026] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the helical blade extends downwardly from the helical surface of the helical blade.

[0027] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends from the surface of the cylindrically shaped wall.

[0028] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends outwardly from the surface of the cylindrically shaped wall.

[0029] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends inwardly from the surface of the cylindrically shaped wall.

[0030] In one embodiment, the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends upwardly of the helical surface of the helical blade.

[0031] In one embodiment, the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends downwardly of the helical surface of the helical blade.

[0032] In one embodiment, the helical blade extends outwardly of the cylindrically shaped wall.

[0033] In one embodiment, the helical pile includes an outwardly extending helical flange that extends outwardly of the cylindrically shaped wall.

[0034] In one embodiment, the helical flange is co-planar with the helical blade.

[0035] In one embodiment, the one or more selected from an aperture and a recess extends upwardly from the helical blade on the cylindrically shaped wall.

[0036] In one embodiment, the one or more selected from an aperture and a recess extends downwardly from the helical blade on the cylindrically shaped wall.

[0037] According to a first aspect, the present invention may be said to involve a helical pile for being inserted into the ground, the helical pile including:a. a helical blade;b. a cylindrically shaped wall extending outwardly of the helical blade; c. wherein the cylindrically shaped wall includes one or more selected from an aperture and a recess in the cylindrically shaped wall.

[0038] In one embodiment, the one or more selected from an aperture and a recess extends into the helical blade.

[0039] In one embodiment, the helical blade includes one or more selected from an aperture and a recess in the helical blade.

[0040] In one embodiment, the one or more selected from an aperture and a recess extends upwardly from the helical blade on the cylindrically shaped wall.

[0041] In one embodiment, the one or more selected from an aperture and a recess extends downwardly from the helical blade on the cylindrically shaped wall.

[0042] In one embodiment, the thickness of the cylindrically shaped wall varies over the length of the cylindrically shaped wall.

[0043] In one embodiment, the thickness of the cylindrically shaped wall tapers between a smaller thickness towards the lower half and a larger thickness towards the upper half.

[0044] In one embodiment, the helical blade extends 360° around its axis.

[0045] In one embodiment, the helical pile includes a central shaft that extends along the axis of the helical blade.

[0046] In one embodiment, the cylindrically shaped wall extends downwardly from an outer edge of the helical blade.

[0047] In one embodiment, the cylindrically shaped wall extends upwardly from an outer edge of the helical blade.

[0048] In one embodiment, the helical blade can include a cutting edge at a lower end.

[0049] In one embodiment, the cutting edge is one or more selected froma. tapered;b. cone-shaped;c. flat ended.

[0050] In one embodiment, the length of the cylindrically shaped wall is betweenl and 10 times the pitch of the helix.

[0051] More preferably, the length of the different cylindrically shaped wall is betweenl and 4 times the pitch of the helix.

[0052] In one embodiment, the aperture is between 1% and 10% of the surface area of the helical blade.

[0053] In one embodiment, at least one edge of the aperture in the helical blade extends from the helical surface of the helical blade.

[0054] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the helical blade extends upwardly from the helical surface of the helical blade.

[0055] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the helical blade extends downwardly from the helical surface of the helical blade.

[0056] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends from the surface of the cylindrically shaped wall.

[0057] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends outwardly from the surface of the cylindrically shaped wall.

[0058] In one embodiment, at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends inwardly from the surface of the cylindrically shaped wall.

[0059] In one embodiment, the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends upwardly of the helical surface of the helical blade.

[0060] In one embodiment, the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends downwardly of the helical surface of the helical blade.

[0061] In one embodiment, the helical blade extends outwardly of the cylindrically shaped wall.

[0062] In one embodiment, the helical pile includes an outwardly extending helical flange that extends outwardly of the cylindrically shaped wall.

[0063] In one embodiment, the helical flange is co-planar with the helical blade.

[0064] Other aspects of the invention are also disclosed.Brief Description of the Drawings

[0065] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0066] Figure 1 shows a top perspective view of a first embodiment of a helical pile;

[0067] Figure 2 shows a bottom perspective view of a first embodiment of a helical pile;

[0068] Figure 3 shows a top perspective view of a second embodiment of a helical pile;

[0069] Figure 4 shows a bottom perspective view of a second embodiment of a helical pile;

[0070] Figures 5 shows a top perspective view of a third embodiment of a helical pile;;

[0071] Figure 6 shows a bottom perspective view of a third embodiment of a helical pile;

[0072] Figures 7 shows a top perspective view of a fourth embodiment of a helical pile;

[0073] Figure 8 shows a bottom perspective view of a fourth embodiment of a helical pile;

[0074] Figures 9 shows a top perspective view of a fifth embodiment of a helical pile;

[0075] Figure 10 shows a bottom perspective view of a fifth embodiment of a helical pile;

[0076] Figures 11 shows a top perspective view of a sixth embodiment of a helical pile;

[0077] Figure 12 shows a bottom perspective view of a sixth embodiment of a helical pile;

[0078] Figure 13 shows a top perspective view of a seventh embodiment of a helical pile;

[0079] Figure 14 shows a top perspective view of an eighth embodiment of a helical pile;

[0080] Figure 15 shows a bottom perspective view of the eighth embodiment of a helical pile;

[0081] Figure 16 shows a top perspective view of a ninth embodiment of a helical pile;

[0082] Figure 17 shows an bottom perspective view of the ninth embodiment of a helical pile;

[0083] Figure 18 shows a top perspective view of a tenth embodiment of a helical pile; and

[0084] Figure 19 shows eight bottom perspective view of the tenth embodiment of a helical pile.

[0085] Figures 20a-20b shows the helical shape of a prior art helical pile (HP-10) used in large scale laboratory testing;

[0086] Figures 20c-20d shows the helical shape of a helical pile according to the invention (HP-9) used in large scale laboratory testing;

[0087] Figure 21 shows a chart of bearing pressure versus s / DHfor different helical shapes including HP-9 and HP-10;

[0088] Figure 22 shows a chart of load test bearing pressures for various helical shapes;

[0089] Figure 23 shows a chart of bearing pressure versus s / DHcurves for HP-9 piles for different helix diameters;

[0090] Figure 24 shows a chart of bearing pressure versus s / DHcurves for HP-9 piles for different embedment depths;

[0091] Figure 25 shows a chart of bearing pressure versus s / DHcurves for HP-10 piles for different cylindrical cap depths;

[0092] Figure 26a-b shows a calibration chart of typical load versus settlement curve, comparing load-settlement curves from large-scale laboratory tests and finite element modelling for (a) H P-9 / 100Z)H / 350zHand (b) HP-10 / 100Z)H / 350ZH;

[0093] Figure 27 shows a chart showing the load versus settlement curves for various helix shapes;

[0094] Figure 28a and b shows stress distribution contours in helical shapes a) HP-09 and b) HP-10;

[0095] Figure 29a and b shows a finite element analysis of generated stresses in a) the modified cylindrical helix (HP-9 / 100Z)H / 350zH.) and b) prior art cylindrical helix (HP-10 / 100Z)w / 350zw.)Description of Embodiments

[0096] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0097] In a first aspect a helical pile is denoted by the reference numeral 1000 and multiples thereof.

[0098] Now described with reference to figures 1 and 2, there is provided a first embodiment of a helical pile 1000. The helical pile 1000 comprises a helical blade 1100, and a cylindrically shaped wall 1200 extending outwardly of the helical blade 1100. The helical blade includes four apertures 1300 that extend through the helical blade 1100. The apertures 1300 include radially extending edges 1310, as well as curved edges 1320.

[0099] The helical blade 1100 extends around a shaft or central shaft 1400 for 360° of rotation. The two opposed ends 1110 of the helical blade 1100 lie adjacent each other at different heights.

[0100] The shaft or central shaft 1400 is preferably hollow towards its upper end, and includes mounting formations 1410 for mounting the central shaft to a larger shaft (not shown) at complementary mounting formations. The mounting formations may be bolt holes or similar. The central shaft 1400 may be reinforced or solid towards its lower end to prevent installation failure.

[0101] The cylindrically shaped wall 1200 extends at a constant distance downwardly from the helical blade, so that the opposed ends 1210 of the cylindrically shaped wall end up being staggered from each other by the pitch of the helical blade. The cylindrical wall forms a chamber within the cylindrical wall. It is envisaged that the more is 1210 of the cylindrically shaped wall 1200 will preferably be secured to each other, for example by welding. However, this need not necessarily be the case.

[0102] In an alternative embodiment (not shown) the cylindrically shaped wall can extend upwardly, or both upwardly and downwardly from an outer edge of the helical blade.

[0103] In a further alternative embodiment (not shown) the cylindrically shaped wall can extend upwardly and / or downwardly from the helical blade at a position inwardly from the outer edge.

[0104] The helical blade 1100 is secured to the central shaft 1400, preferably by welding, although it is envisaged that alternative securing formations may be used. The central shaft 1400 ends along the axis of the helical blade 1100.

[0105] It is envisaged that the helical blade 1100 could extend for an increased or decreased amount of rotation about the central shaft 1400. It is envisaged that the helical blade 1100 could overlap itself, for example if it extended for more than 360° around the central shaft 1400.

[0106] The apertures 1300 are spaced regularly around the central shaft 1400. In the embodiment shown in figures 1 and 2, the edges 1310, 1320 of the aperture are evenly thick.

[0107] It is envisaged that the diameter of the cylindrically shaped wall will preferably be between 1 and 10 times the pitch of the helix, and more preferably between 1 and 4 times the pitch of the helix.

[0108] Preferably, the aperture 1300 is between 1% and 10% of the surface area of the helical blade.

[0109] In a second embodiment as shown in figures 3 and 4, a helical pile 2000 is shown. In this embodiment, the helical pile 2000 includes a helical blade 2100, a cylindrically shaped wall 2200 and a central shaft 2400. However, in this embodiment, a pair of apertures 2300 are provided in the helical wall 2100 that extend as recesses from an edge of the helical blade adjacent the central shaft 2400 to a distance that is about half the width of the helical blade 2100.

[0110] The helical blade 2100 varies in thickness from being thicker towards the central shaft 2400 and tapers to being thinner at its outer edge 1220. The aperture 2300 includes radially extending edges 2310 and curved edges 2320.

[0111] The helical blade 2100 extends around a central shaft 2400 for 360° of rotation. The two opposed ends 2110 of the helical blade 2100 lie adjacent each other at varying heights. The cylindrically shaped wall 2200 extends at a constant distance downwardly from the helical blade, so that the opposed ends 2210 of the cylindrically shaped wall end up being staggered from each other by the pitch of the helical blade. It is envisaged that the ends 2210 of the cylindrically shaped wall 2200 will preferably be secured to each other, for example by welding. However, this need not necessarily be the case.

[0112] A third embodiment of a helical pile 3000 is shown in figures 5 and 6. In this embodiment, the helical pile 3000 includes helical blade 3100, a cylindrically shaped wall 3200, and a central shaft 3400. The helical pile 3000 is similar to the first embodiment of a helical pile 1000 shown in figures 1 and 2. However, the helical pile 3000 furtherincludes apertures 3500 extending through the cylindrically shaped wall 3200. The apertures 3500 are diametrically opposed to each other, however it is envisaged that in alternative embodiments (not shown) the more apertures could be placed at any location, but would preferably be spaced regularly around the cylindrically shaped wall 3200. The central shaft 3400 preferably extends to a point 3410 at its lower end.

[0113] A fourth embodiment of a helical pile 4000 Is shown in figures 7 and 8. The helical pile 4000 includes a helical blade 4100, a cylindrically shaped wall 4200 and a central shaft 4400. In this embodiment, apertures 4600 are provided that extend from the helical blade 4100 into the cylindrically shaped wall 1200. In the embodiment shown, the apertures extend fully downwardly along the length of the cylindrically shaped wall 4200. In this way, the apertures 4600 may also be regarded as being recesses extending inwardly from a lower edge of the cylindrically shaped wall 4200. In this embodiment, three apertures 4600 are provided that are spaced regularly between opposed ends 4110 of the helical blade 4100, however it is envisaged that in alternative embodiments (not shown) any number of apertures 4600 may be provided, and that they need not be regularly spaced.

[0114] It is envisaged that the sizes of the apertures 4600 can be changed based on soil conditions.

[0115] In an alternative seventh embodiment of a helical pile shown in figure 13, the aperture 700 extends from the helical blade 7100 onto the cylindrically shaped wall 7200, but extend only along only a portion of the length of the cylindrically shaped wall.

[0116] A fifth embodiment of a helical pile 5000 is shown in figures 9 and 10. In the fifth embodiment, the helical pile 5000 includes helical blade 5100, a cylindrically shaped wall 5200 extending downwardly from the helical blade 5100, and a central shaft 5400 around which the helical blade 5100 extends in a helical fashion. Four apertures 5300 extend through the helical blade 5100 at regular spacings around the central shaft 5400. Downwardly extending walls 5330 extend out of the plane of the helical blade and downwardly from an edge of each of the apertures 5300 to a position below the lower surface of the helical blade 5100. Preferably the downwardly extending walls 5330 taper to a sharpened lower edge 5332. It is envisaged that the downwardly extending walls 5330 will serve to guide soil being compacted underneath the helical blade 5100 from underneath the helical blade to above the helical blade in use.

[0117] The helical pile 5000 further includes apertures 5500 in the cylindrically shaped wall.

[0118] It is further envisaged that in alternative embodiments (not shown) walls may be provided with similar tapered walls that may serve to guide compacted soil from within the cylindrically shaped wall to outside of the cylindrically shaped wall, or vice versa.

[0119] A sixth embodiment of a helical pile 6000 is shown in figures 11 and 12. In this sixth embodiment, the helical pile 6000 includes helical blade 6100, cylindrically shaped wall 6200 extending downwardly from the helical blade 6100, and a central shaft 6400 around which the helical blade 6100 extends into helical fashion. Four apertures 6300 extend through the helical blade 6100 at regular spacings around a central shaft 6400.

[0120] Curved upwardly extending walls 6340 extend upwardly from a curved edge of the apertures 6300. Such curved upwardly extending walls 6340 are used, once the helical pile 6000 is embedded within the soil, to provide further resistance to lateral movements of the central shaft 6400 through the soil after being installed, while at the same time allowing compacted soil to traverse through the helical blade 6100 while the helical pile 6000 is being installed. The helical pile 6000 further includes apertures 6500 in the cylindrically shaped wall 6200. The apertures 6500 further includes outwardly extending walls 6510 that extend substantially outwardly on a horizontal plane. Outwardly extending walls 6510 further serve to resist turning moments on the helical pile 6000 once the helical pile is installed, while allowing for equalisation of soil pressures between the inside and the outside of the cylindrically shaped wall 6200 during installation.

[0121] It is envisaged that in alternative embodiments (not shown) the thickness of the cylindrically shaped wall may vary over the length of the cylindrically shaped wall. Preferably, the thickness of the cylindrically shaped wall tapers between a smaller thickness towards the lower edge and a larger thickness towards the upper edge.

[0122] In another alternative embodiment (not shown), the helical blade can include a cutting edge at a lower end, in that the leading lower edge of the helical blade may be sharpened to more easily cut through soil. The cutting edge can be tapered, cone-shaped or flat ended.

[0123] In alternative embodiments (not shown), it is envisaged that the perforations or apertures and / or recesses can be of various shapes, for example circular, square, trapezoidal, triangular, or the like. Further, the apertures and / or recesses can be of different sizes to accommodate the particle sizes of the soil that will be passing through.

[0124] Further, depending on the soil type, helical pile dimensions, and embedment depth, the length of the cylindrical chamber is preferably between 1 and 10 times the pitch of the helix, and more preferably between 1 and 4 times the pitch of the helix.

[0125] It is envisaged that the location, number, size and shape of the apertures or perforations on the cylindrical chamber or the helix flange, or both can be varied based on the type of soil and the dimensions of the helical pile.

[0126] It is believed that the effect of pro’s viding embodiments of a helical pile with features in accordance with the above may be to increase the bearing capacity of the helical pile. Additionally and / or alternatively, it may be to increase the friction resistance between the helical pile in the soil. Additionally and / or alternatively, it may be to reduce the total settlement of the helical pile. Additionally and / or alternatively it’s may be to remove undesirable material from underneath the helical blade during installation. Additionally and / or alternatively it may be to reduce the installation depth of the helical pile to achieve a required bearing capacity. Additionally and / or alternatively, it may be too reduced installation resistance, requiring less energy in the installation of the pile.

[0127] An eighth embodiment of a helical pile 8000 is shown in figures 14 and 15. In this embodiment, the cylindrically shaped wall 8200 extends upwardly from the helical blade 8100, and not downwardly as shown in the previous embodiments. Apertures 8300 are also provided in the helical blade 8100. It is envisaged that apertures may also be provided in the cylindrically shaped wall.

[0128] It is further envisaged that any of the previously shown embodiments of the helical pile can include cylindrically shaped walls that extend upwardly from the helical blade instead of downwardly. It is further envisaged that any of the previously shown embodiments of the helical pile can include cylindrically shaped wall that extend both upwardly and downwardly from the helical blade.

[0129] A ninth embodiment of a helical pile 9000 is shown in figures 16 and 17. The helical pile 9000 includes a helical blade 9100 and a cylindrically shaped wall 9200. The cylindrically shaped wall 9200 includes an upwardly extending portion 9220 as well as a downwardly extending portion 9230. The helical blade 9100 further defines apertures 9300 through it.

[0130] A tenth embodiment of a helical pile 10000 is shown in figures 18 and 19. In this embodiment, the helical blade 10100 extends outwardly of the cylindrically shaped wall 10200 as helical flange 10700. The cylindrically shaped wall 10200 in turn also extends upwardly from the helical blade 10,100 in an upwardly extending portion 10220 as well as downwardly from the helical blade 10,300 in a downwardly extending portion 10,230.

[0131] In an alternative embodiment (not shown) it is envisaged that the helical flange 10,700 can also include one or more selected from recesses and apertures.Examples

[0132] Tests have been conducted on the shapes presented in Figures 20a-b (showing prior art configurations HP-10) and Figure 20c-d (showing a configuration HP-9 according to the present invention). An axial compressive load test was carried out on 10 different helical piles. The bearing pressure versus S / DH curves for various helical shapes are presented in Figure 21. As found in this study, the helical shape has a significant effect on the helical pile bearing pressure and performance and is considered one of the significant factors of the helical pile configurations. The performance of the developed helical shape (HP-9 and HP-10) with a cylindrically shaped wall surrounding the helical blade, increases the bearing pressure to 203 and 208kPa, respectively. Which represents a 25.3% and 28.4% improvement in the helical pile bearing pressure compared to conventional helical piles such as HP-1.

[0133] Figure 22 presents the performance of differently shaped helical piles including HP-9 and HP-10 mentioned above

[0134] This study investigated five different diameters (80, 90, 100, 110, and 120 mm), which corresponded to a 12.5%, 25%, 37.5%, and 50% increase in helix diameter when compared to HP-9 / 80DH / 350ZH. Figure 23 shows that the bearing pressure was found to be affected by the helical pile diameter. As expected, the ultimate bearing pressure rises with the helical pile diameter. This could be because increasing the diameter of the helical pile increases the diameter of the failure bulb that surrounds the helix.

[0135] The axial load test results for the HP-9 pile at various installation depths are shown in Figure 24. In this study, four different installation depths (e.g., 250, 300, 350, and 400 mm) were used to investigate the effect of installation depth on the bearing pressure response of the helical pile, which corresponds to a 20%, 40%, and 60% increase in installation depth when compared to HP-9 / 80DH / 350ZH. AS shown in Figure 24, the bearing pressure increases with the increase of the embedment depth. Although increasing the installation depth increases the shaft resistance area, the helix diameter has a greater influence on generating helical pile bearing pressure.

[0136] Figure 25 represents the bearing pressure versus S / DH for different cylindrical cap depths for HP-9. The performance was investigated for three cap depths (0, 15, and 30mm), which represent 0%, 100%, and 200% of the helix pitch. Figure 25 shows that the bearing pressure was found to be affected by the cylindrical cap depth. As expected, the ultimate bearing pressure increases with the helical pile cap increase. The soil confined within the chamber experiences densification inside the cylindrical chamber,increasing bearing pressure. Increasing the cylindrical cap depth increases the friction between the soil and the cap wall.

[0137] Figure 26 shows the typical load versus settlement curve of a) HP-9 and b) HP-10 helical shapes during axial compressive load testing. The helical pile settlement increases with the increase in the bearing pressure. The finite element model results capture the load versus settlement in the same way as the large-scale laboratory tests for the developed helical shapes (HP-9 and HP-10). To understand the performance of the helical piles with the innovative shape in more detail, a field-size helical pile with the new shape was examined to study the effect of the shape on real-life-size helical piles. Figure 27 illustrates the comparison between the HP-9, HP-10 and a traditional helix shape performance for field-size helical piles.

[0138] Figure 27 shows the modified cylindrical helix HP-9 ultimate load at 9mm settlement is 231 kN and for the cylindrical helix HP-10 the load is 244kN, which represents 10.5% and 16.7% change in comparison to the traditional helix.

[0139] Figures 28 a and b illustrates the stress contours in the soil during the load testing for the modified cylindrical helix and cylindrical helix (HP-9 and HP-10). Both shapes are subjected to the same amount of displacement (10mm) to investigate the amount of the transfer stress from the applied load to the soils surrounding the helical pile. The maximum stress generated in the soil during load testing for HP-9 is 325.2kPa and for the HP-10 is 334kPa. The figure illustrates the stresses in the cylindrical helix developed inside the cylindrical chamber and the highest level of stresses generated directly below the pile tip and the stresses extend to the corners of the cylindrical chamber. Creating the cylindrical chamber leads to densifying the soil inside the chamber, which increases the contact area between the soil particles and improves the soil's capacity to hold the transferred stress from the helical pile. Interestingly, the stress developed in the modified cylindrical chamber extended to the apertures. This can be related to the apertures in the helix. Adding the apertures in the helix densifies the soil, which allows the densified soil to pass through the apertures. Thus, the cylindrical chamber densifies the soil up to the outer edge of the aperture. Reducing the amount of densified soil inside the cylindrical chamber from the edge of the chamber to the edge of the apertures leads to reduce the ultimate bearing capacity of the pile. The influence zone of the transferred stress extends horizontally up to 2.4 times the diameter of the helix for both HP-09 and HP-10. Vertically, the influence zones extend below the helix up to 3.1 times the helix diameter for HP-09 and 3.2 times for HP-10.

[0140] Figures 29a and b presents the stresses generated in the helix during the load testing for both modified cylindrical helix and cylindrical helix (HP-09 and HP-10). The generated stresses in the helices are examined at the end of the static load testing to capture the maximum stresses generated in the helices. The maximum stress generated in the soil after load testing for the modified cylindrical helix is 55.52MPa, and for the cylindrical helix is 110.7MPa. As Figures 29a and b illustrates, the stresses generated inside the cylindrical helix HP-10 are about 2 times the stresses generated in the modified cylindrical helix HP-9. On the other hand, the increase in the bearing capacity is only about 2% higher. Introducing the apertures to helix HP-9 transfers the stresses from the helix to the surrounding soils, and then the soil passes through the apertures, thereby offloading the stresses from the helix to the surrounding soils. In contrast, in the cylindrical helix HP-10’s case, the cylindrical helix encloses the soil inside the cylindrical chamber and prevents the soil from passing which concentrates the stresses inside the helix. Lower stress levels inside the helix indicate that the material is less likely to have plastic deformation or failure over time. In addition, this may allow HP-9 to bear additional loads. It is worth noting that the generated stress inside the cylindrical chamber is generated along the whole helix structure, which shows similar behaviour for the stresses transferred to soil in Figures 28b. For the modified cylindrical helix shape HP-9, the highest stress levels were generated from the apertures to the pile tip, illustrating the distinct mechanism by which stresses transfer from the helix to the surrounding soil, as shown in Figure 28a.Interpretation

[0141] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. For the purposes of the present invention, additional terms are defined below. Furthermore, all definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms unless there is doubt as to the meaning of a particular term, in which case the common dictionary definition and / or common usage of the term will prevail.

[0142] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, thesingular articles “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise and thus are used herein to refer to one or to more than one (i.e. to “at least one”) of the grammatical object of the article. By way of example, the phrase “an element” refers to one element or more than one element.

[0143] The term “about” is used herein to refer to quantities that vary by as much as 30%, preferably by as much as 20%, and more preferably by as much as 10% to a reference quantity. The use of the word ‘about’ to qualify a number is merely an express indication that the number is not to be construed as a precise value.

[0144] Throughout this specification, unless the context requires otherwise, the words “comprise”, “comprises” and “comprising” will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements.

[0145] The term “real-time” for example “displaying real-time data,” refers to the display of the data without intentional delay, given the processing limitations of the system and the time required to accurately measure the data.

[0146] As used herein, the term “exemplary” is used in the sense of providing examples, as opposed to indicating quality. That is, an “exemplary embodiment” is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality for example serving as a desirable model or representing the best of its kind.

[0147] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0148] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as“only one of” or “exactly one of,” or, when used in the claims, “consisting of’ will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0149] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. Embodiments:

[0150] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0151] Similarly, it should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the variousinventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detailed Description of Specific Embodiments, with each claim standing on its own as a separate embodiment of this invention.

[0152] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are envisaged and intended to be within the scope of the invention, and form different embodiments, as would be understood by those in the art, unless such combinations of features are not logically possible. For example, in the following claims, any of the claimed embodiments can be used in any combination.Specific Details

[0153] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0154] It will be appreciated that the methods / apparatus / devices / systems described / illustrated above at least substantially provide a helical pile.

[0155] The helical pile described herein, and / or shown in the drawings, are presented by way of example only and are not limiting as to the scope of the invention. Unless otherwise specifically stated, individual aspects and components of the helical pile may be modified, or may have been substituted therefore known equivalents, or as yet unknown substitutes such as may be developed in the future or such as may be found to be acceptable substitutes in the future. The helical pile may also be modified for a variety of applications while remaining within the scope and spirit of the claimed invention, since the range of potential applications is great, and since it is intended that the present invention be adaptable to many such variations.Terminology

[0156] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner toaccomplish a similar technical purpose. Terms such as "forward", "rearward", "radially", "peripherally", "upwardly", "downwardly", and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.Different Instances of Objects

[0157] As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.Combinations of features in embodiments

[0158] Different features are described in different embodiments in this specification, however it is envisaged that any features shown in any embodiment described may be used with any other features in any other embodiment in any combination, unless this is not logically possible.Comprising and Including

[0159] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0160] Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.Scope of Invention

[0161] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[0162] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.Chronological order

[0163] For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be carried out in chronological order in that sequence, unless there is no other logical manner of interpreting the sequence.Markush groups

[0164] In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.Industrial Applicability

[0165] It is apparent from the above, that the arrangements described are applicable to the pile driving and construction industries.

Claims

Claims1. A helical pile for being inserted into the ground, the helical pile including:a. a helical blade;b. a cylindrically shaped wall extending outwardly of the helical blade; c. wherein the helical blade includes one or more selected from an aperture and a recess in one or more selected from the helical blade and the cylindrically shaped wall.

2. The helical pile as claimed in claim 1, wherein the one or more selected from an aperture and a recess extends between the helical blade and the cylindrically shaped wall.

3. The helical pile as claimed in either of claims 1 or 2+, wherein the thickness of the cylindrically shaped wall varies over the length of the cylindrically shaped wall.

4. The helical pile as claimed in any one of claims 1 to 3, wherein the thickness of the cylindrically shaped wall tapers between a smaller thickness towards the lower half and a larger thickness towards the upper half.

5. The helical pile as claimed in any one of claims 1 to 4, wherein the helical blade extends 360° or more around its helical axis.

6. The helical pile as claimed in any one of claims 1 to 5, wherein the helical pile includes a central shaft that extends along the axis of the helical blade.

7. The helical pile as claimed in any one of claims 1 to 6, wherein the cylindrically shaped wall extends in a direction that is one or more selected froma. downwardly from an outer edge of the helical blade; andb. downwardly from an outer edge of the helical blade.

8. The helical pile as claimed in any one of claims 1 to 7, wherein the helical blade includes a cutting edge at a lower end.

9. The helical pile as claimed in any one of claims 1 to 8, wherein the length of the cylindrically shaped wall is between 1 and 10 times the pitch of the helix.

10. The helical pile as claimed in any one of claims 1 to 9, wherein the aperture in the helical blade is between 1% and 10% of the surface area of the helical blade.

11. The helical pile as claimed in any one of claims 1 to 10, wherein at least one edge of the aperture in the helical blade extends in a direction that is one or more selected froma. upwardly from the helical surface of the helical blade; andb. downwardly from the helical surface of the helical blade.

12. The helical pile as claimed in any one of claims 1 to 11, wherein at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends from the surface of the cylindrically shaped wall.

13. The helical pile as claimed in any one of claims 1 to 12, wherein at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends outwardly from the surface of the cylindrically shaped wall.

14. The helical pile as claimed in any one of claims 1 to 13, wherein at least one edge of the at least one or more selected from an aperture and a recess in the cylindrically shaped wall extends inwardly from the surface of the cylindrically shaped wall.

15. The helical pile as claimed in any one of claims 1 to 14, wherein the one or more selected from an aperture and a recess extends upwardly from the helical blade on the cylindrically shaped wall.

16. The helical pile as claimed in any one of claims 1 to 15, wherein the one or more selected from an aperture and a recess extends downwardly from the helical blade on the cylindrically shaped wall.

17. The helical pile as claimed in any one of claims 1 to 16, wherein the helical pile includes an outwardly extending helical flange that extends outwardly of the cylindrically shaped wall.

18. The helical pile as claimed in claim 17, wherein the helical flange is co-planar with the helical blade.END

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