An anchor pile for expediently penetrating the seabed, lakebed or ground

Technical field of the invention

The present invention relates to foundations for constructions above a water or wetland, and more particularly to the use of specific anchor piles as a substitute for traditional vertical poles.

Background of the invention

In regions where the lakes and/or shore line waters freeze over during winter time, it is necessary to remove docks, boathouses, jetties, and the like before the winter arrives. Otherwise, the formed ice will damage the constructions. Prior art has tried to use aerating means to stir the water around the vertical poles.

However, this solution needs electrical power, and consumes a lot of energy.

It is therefore desirable to provide a system, which can allow docks, boathouses, jetties to survive harsh winters without the use of electricity.

Summary of the invention

The inventor has found that the vertical poles may be exchanged with hollow anchor piles comprising a tubular shaft with a proximal end and a distal end, and first and second helical plates extending outwardly from said shaft and secured thereto. The first helical plate (leading helix) is positioned at the distal end, and the distal end comprises at least two slots or holes in its tubular wall. When the anchor pile is torqued into the seabed, lakebed or wetland ground, the slots or holes direct the heat therefrom up (often about 8 degrees Celsius during winter) through the hollow anchor pile, thereby defrosting it, and the surrounding water will not freeze. A first aspect relates to the use of a plurality of anchor piles as a foundation for a construction above a water (such as a lake or a sea) or wetland; wherein the anchor piles are of a length extending above the waterline when mounted in the seabed, lakebed or wetland ground;

wherein the anchor pile comprises a tubular shaft with an open proximal end and a distal end, and a first (leading helix) and second (trailing helix)

helical plates, extending outwardly from said shaft and secured thereto;

wherein the first helical plate is positioned at the distal end;

wherein the distal end comprises at least two slots or holes in its tubular wall.

A second aspect relates to an anchor pile for expediently penetrating the seabed, lakebed or ground, the anchor pile comprising a tubular shaft with an open proximal end and a distal end, and a first (leading helix) and second (trailing helix) helical plates, extending outwardly from said shaft and secured thereto;

wherein the first helical plate is positioned at the distal end;

wherein the distal end comprises at least two slots or holes in its tubular wall.

In one or more embodiments, the at least two slots or holes are positioned just above the tip of the distal end. This position is chosen to secure maximal heating through the entire tubular shaft. If the slots or holes are positioned at the tip, i.e. that the distal end is open, the effect of heating is observed to be less - probably due to the open end being closed with dirt. Further slots or holes along the tubular shaft are thought to be less efficient as cooler regions, e.g. in the water, are thought to cancel the heating effect from the ground or bed. A single slot or hole does not provide the same effect as two slots or holes, and further slots or holes risk weakening the tubular shaft too much.

In one or more embodiments, the width or diameter of the at least two slots or holes is within the range of 5-25 mm, and preferably about 10 mm. The tubular shaft and the helical plates are preferably made from steel, and more preferably from galvanized steel. The tubular shaft of the anchor pile may have different shapes, with cross-sections being e.g. round, oval, circular, triangular or squared, but it must be hollow. Preferably, the cross-section is round as there is less friction during the piling operation.

Preferably, the tip of the distal end is configured as a ground penetrating means adapted for selectively penetrating the ground, and for guiding the tubular (e.g. hollow cylindrical) shaft into the seabed, lakebed, and/or ground. The ground penetrating means may advantageously be configured as an elongate rod, preferably 15-30 cm long, and with a cross-sectional width or diameter of 5-35 mm. Prior art tips of anchor piles have been shown with a 45-degree end.

However, these ends do not guide the pile perpendicularly into the ground or bed. Rather, they tend to lead the pile into the ground slightly angled. Preferably, the elongate rod is 20 cm long, and with a circular cross-section of 20 mm.

Preferably the rod tip is blunt, as it would otherwise be too fragile in an encounter with a stone or the like in the ground or lakebed.

Known anchor piles of the same type (screw piles) as the anchor pile of the present invention, have disadvantages. When the soil is displaced by the helical discs during the piling, the soil is loosened to such an extent that the pile stability is weakened. The inventor has found that it is crucial to the pile stability that the shaft is provided with helical plates with less than two turns, and that the helical plates are spaced from one another, such that they follow the same track when moving through the ground. It is a non-limiting theory by the inventor that the soil will otherwise be loosened/disturbed too much for the anchor pile to anchor in the ground. When testing an anchor pile with a helical plate spanning the whole shaft, hardly no anchoring was observed (one was able to lift it free of the ground with very low pull force applied). When varying the length of the turns (the pitch opening) from wide to narrow along the helical axis, the anchoring was

worsened. Reducing the amount of helical spanning along the shaft to one or more regions with multiple turns did not solve the problem to a satisfactory level. It was then tried to reduce the amount of turns in the individual helical plate to a single turn around the shaft (i.e. a 360 degree turn, in practice a 358 degree turn). This improved the anchoring to a certain extent. However, an acceptable anchoring was first obtained when a specific combination of the distance and relative position between the helical plates was found. The helical plates must be spaced at distances far enough apart, such that they function independently as individual bearing elements.

A third aspect relates to an anchor pile for expediently penetrating the seabed, lakebed, or ground, the anchor pile comprising a tubular shaft with an open proximal end and a distal end, and a first and a second helical plates, extending outwardly from said shaft and secured thereto;

wherein the first helical plate is positioned at the distal end;

wherein the distance between the first and second helical plates is at least 80 cm, and the diameter of the first and second helical plates is within the range of

15-80 cm;

wherein an individual helical plate spans 270-450 degrees around the shaft; wherein the helical plates are spaced from one another, such that they follow the same track when moving through the seabed, lakebed, and/or the ground;

wherein the tip of the distal end is configured as a ground penetrating means adapted for selectively penetrating the ground, and for guiding the tubular shaft into the seabed, lakebed, and/or ground;

wherein the distal end comprises at least two slots or holes in its tubular wall.

As mentioned, the helical plates must be spaced at distances far enough apart, such that they function independently as individual bearing elements. However, the inventor was surprised to see that a specific distance worked surprisingly better than others. In general, screw piles offer some structural resistance to tensile and compressive forces. When testing the tensile and compressive load on anchor piles with different distances between the first and second helical plates, the inventor surprisingly found a specific distance that showed markedly better tensile load than the others. The distance between the first and second helical plates was tested within the range of 20-150 cm, and with 10 cm intervals. Distances within the range of 20-50 cm were generally poor, while improvement was seen within the range of 60-80 cm. The tensile load of an anchor pile with 90 cm between the first and second helical plates showed 39% better tensile load than the second best with a distance of 100 cm between the first and second helical plates. Distances within the range of 110-150 cm were better than distances within the range of 20-80 cm, but lower than 90 cm and 100 cm distances. The compressive load at the 90 cm distance was only 5% better than the compressive load of the anchor pile with a 100 cm distance between the first and second helical plates. The test was conducted with a first helical plate having a diameter of 20 cm, and a second helical plate having a diameter of 40 cm.

In one or more embodiments, the diameter of the first helical plate is within the range of 15-25 cm, and the second helical plate is within the range of 35-45 cm.

In one or more embodiments, the first helical plate has a diameter within the range of 15-25 cm; wherein the second helical plate has a diameter within the range of 35-45 cm; and wherein the distance between the first and second helical plates is within the range of 85-95 cm.

In one or more embodiments, the first helical plate has a diameter of 20 cm;

wherein the second helical plate has a diameter of 40 cm; and wherein the distance between the first and second helical plates is 90 cm.

For applications requiring deeper penetration underground for better load- bearing capabilities, it may be necessary to lengthen the anchor pile.

In one or more embodiments, the anchor pile further comprises an open ended tubular extension shaft; wherein the proximal end of the shaft is adapted for coupling to said extension shaft; wherein the extension shaft comprises a shaft with a proximal end and a distal end, and at least one helical plate extending outwardly from said shaft and secured thereto; and wherein when the shaft of the anchor pile is coupled to the extension shaft, the helical plates of the extension shaft and the anchor pile are spaced from one another, such that they follow the same track when moving through the ground.

In one or more embodiments, the distance between the first helical plate and the helical plate on the extension shaft is at least 200 cm.

In one or more embodiments, the distance between the first helical plate and the helical plate on the extension shaft is 210 cm; wherein the diameter of the helical plate on the extension shaft is 40 cm; wherein the first helical plate has a diameter of 20 cm; wherein the second helical plate has a diameter of 40 cm; and wherein the distance between the first and second helical plates is 90 cm.

In one or more embodiments, the individual helical plate spans 270-450 degrees around the shaft, such as within the range of 275-445 degrees, e.g. within the range of 280-440 degrees, such as within the range of 285-435 degrees, e.g. within the range of 290-430 degrees, such as within the range of 295-425 degrees, e.g. within the range of 300-420 degrees, such as within the range of 305-415 degrees, e.g. within the range of 315-410 degrees, such as within the range of 320-405 degrees, e.g. within the range of 325-400 degrees, such as within the range of 330-395 degrees, e.g. within the range of 335-390 such as within the range of 340-385 degrees, e.g. within the range of 345-380 degrees, such as within the range of 350-365 degrees, e.g. within the range of 355-360 degrees around the shaft. Preferably, the individual helical plate spans 340-360 degrees around the shaft, e.g. 358 degrees around the shaft or 359 degrees around the shaft. In a preferred embodiment, each helical plate forms a substantially 360-degree helical turn.

The first, second, and possible other helical plates are spaced from one another, such that they follow the same track when moving through the ground. This is e.g. possible when the pitch opening is the same for all helical plates, such as 10 cm, and when the distance (e.g. 90 cm) between the individual plates is an integer (e.g. 9) of said distance. The distance may e.g. be measured from the leading edge of the upper helical plate to the leading edge of a lower helical plate; or from the tailing edge of the upper helical plate to the tailing edge of a lower helical plate.

Generally, the helical plates have a pitch angle substantially within the range of 5-90 degrees, such as within the range of 10-85 degrees, e.g. within the range of 15-80 degrees, such as within the range of 20-75 degrees, e.g. within the range of 25-70 degrees, such as within the range of 30-65 degrees, e.g. within the range of 35-60 degrees, such as within the range of 40-55 degrees, e.g. within the range of 45-50 degrees.

In one or more embodiments, the helical plates have a pitch angle substantially within the range of 5-50 degrees, such as within the range of 10-45 degrees, e.g. within the range of 15-40 degrees, such as within the range of 20-35 degrees, preferably within the range of 15-30 degrees.

In one or more embodiments, the pitch opening is at least 5 cm, such as within the range of 5-50 cm, e.g. 10-45 cm, such as within the range of 15-40 cm, e.g. 20-35 cm, such as within the range of 25-30 cm. In the present context, the pitch opening is determined by the pitch angle of the helical plate in a 360-degree turn and corresponds to the distance between the threads of the helical plate for each 360-degree rotation of helical plate. In other words, the pitch opening is equivalent to approximately the distance from the top of the bottom portion of the plate at the leading edge to the bottom of the top portion of the opposing side of the plate at the trailing edge. Preferably, the pitch opening is at least 5 cm, such as within the range of 5-15 cm, e.g. 6-14 cm, such as within the range of 7-13 cm, e.g. 8-12 cm, such as within the range of 9-11 cm.

The anchor pile may be positioned by a system comprising:

- a hydraulic system configured to torque an anchor pile into the ground;

- means for applying pressure onto an anchor pile during positioning; and

- an anchor pile stability indicator.

Furthermore, in order to avoid skidding of the anchor pile during the piling operation, and thereby loosening the soil, the system for positioning the anchor pile may also include means for applying pressure onto the anchor pile during positioning.

It is a problem to asses when the anchor pile is positioned sufficiently deep to provide a wanted anchor pile stability. The inventor therefore provided a system where an anchor pile stability indicator is included.

The distal end of the anchor pile faces the ground during operation, and the proximal end is the opposite end, preferably facing the hydraulic system configured to torque the anchor pile into the ground.

The inventor has found a correlation between the fluid pressure within the hydraulic system and the anchor pile stability. Thereby, it is possible to estimate the anchor pile stability by measuring the fluid pressure within the hydraulic system.

The hydraulic system comprises hydraulic fluid, a hydraulic motor, a hydraulic pump supplying hydraulic fluid to the individual components in the system, preferably control valves for directing the hydraulic fluid flow, a hydraulic fluid reservoir, and hydraulic tubes. A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation).

In one or more embodiments, the proximal end of the shaft is adapted for connecting to the hydraulic motor.

In one or more embodiments, the anchor pile stability indicator is a manometer configured to measure the hydraulic fluid pressure within the hydraulic system.

In one or more embodiments, the anchor pile stability indicator is a manometer configured to measure the hydraulic fluid pressure within the hydraulic tubes.

In one or more embodiments, the anchor pile stability indicator is configured to measure the fluid pressure within the hydraulic system, such as within the hydraulic tubes, and compare said fluid pressure with one or more reference patterns of fluid pressure and anchor pile stability.

In one or more embodiments, the anchor pile stability indicator is a manometer configured to measure the fluid pressure within the hydraulic system, such as within the hydraulic tubes, and compare said fluid pressure with one or more reference patterns of fluid pressure and anchor pile stability.

In one or more embodiments, the anchor pile stability indicator is configured to continuously measure the fluid pressure within the hydraulic system, such as within the hydraulic tubes.

In one or more embodiments, the system further comprises a ground positioning system configured for determining the ground position of the anchor pile.

If an unexpected event occurs with e.g. a building positioned on top of the piled ground area, it may be an advantage to log all data to an individual anchor pile in order to trace back how stable the specific area was estimated to be. In one or more embodiments, the system further comprises a processor configured to pair the ground position of the anchor pile with the data obtained by the anchor pile stability indicator, and store it in a database.

When an operator is using the system from e.g. a mini excavator, it may be difficult for him to see the progress of the anchor pile entering the ground.

Flence, in one or more embodiments, the anchor pile stability indicator is configured to signal when a preset anchor pile stability is reached.

In one or more embodiments, the anchor pile stability indicator is configured to provide a first signal when the pile stability is below a preset anchor pile stability, and to provide a second signal when a preset anchor pile stability is reached, to insure that the installation is completed in the correct manner. The signal may be a sound signal, a light signal, or a combination of both.

Brief description of the figures

Figure 1 shows a system for positioning an anchor pile in accordance with various embodiments of the invention;

Figure 2 shows an anchor pile in accordance with various embodiments of the invention; and

Figure 3 shows an extension shaft in accordance with various embodiments of the invention.

Detailed description of the invention

Referring to Figure 1 , the general scheme of the invention is shown. Figure 1 shows a system 100 for positioning an anchor pile in accordance with various embodiments of the invention. The system 100 comprises a hydraulic system 300 configured to torque an anchor pile 200 into the ground, means 400 for applying pressure onto an anchor pile 200 during positioning, and an anchor pile stability indicator 500 - here shown coupled to a hydraulic tube 302.

The anchor pile 200 has a proximal end 203 coupled to the distal end 605 of an extension shaft. The proximal end 603 of the extension shaft is coupled to a hydraulic motor 304 being part of the hydraulic system 300.

The anchor pile 200 is shown comprising a tubular shaft 202 with an open proximal end 203 and a distal end 205, and a first 204A and a second 204B helical plates, extending outwardly from said shaft 202 and secured thereto.

The first helical plate 204A is positioned at the distal end 205. The distance between the first 204A and second 204B helical plates is 90 cm. The diameter of the first 204A helical plate is 20 cm, and the second helical plate 204B is 40 cm. The helical plates 204A, 204B both span 358 degrees around the shaft 202. The helical plates 204A, 204B are spaced from one another, such that they follow the same track when moving through the seabed, lakebed, and/or the ground.

The extension shaft is shown with one helical plate 604 extending outwardly from the shaft 602 and secured thereto. The helical plates 604, 204 of the extension shaft and the anchor pile are spaced from one another, such that they follow the same track when moving through the ground. The distance between the second helical plate 204B and the helical plate 604 on the extension shaft, when the tubular shaft is coupled to the extension shaft, is 120 cm.

Figure 2 shows a closeup view of the anchor pile from Figure 1. The anchor pile 200 here shows that the distal end 205 comprises holes 206 in its tubular wall. Two holes are present, but only one may be seen in this view. The tip 207 of the distal end 205 is configured as a ground penetrating means adapted for selectively penetrating the ground, and for guiding the tubular shaft 202 into the seabed, lakebed, and/or ground.

Figure 3 shows an extension shaft in accordance with various embodiments of the invention. The extension shaft (600) comprises a shaft (602) with a proximal end (603) and a distal end (605), and at least one helical plate (604) extending outwardly from said shaft (602) and secured thereto. The distal end (605) of the shaft (202) is adapted to be coupled to the proximal end (203) of the anchor pile (200). When the extension shaft and the anchor pile are coupled together, the helical plates of the extension shaft and the anchor pile are spaced from one another, such that they follow the same track when moving through the ground.

References

100 System

200 Anchor pile

202 Shaft

203 Proximal end

204 Helical plate

205 Distal end

206 Slot or hole

207 Tip

300 Hydraulic system

302 Hydraulic tube

304 Hydraulic motor

400 Means for applying pressure onto the anchor pile

500 Anchor pile stability indicator

600 Extension shaft

602 Shaft

603 Proximal end

604 Helical plate

605 Distal end