TW202403151A - Foundation for a structure and method of installing the same - Google Patents

Abstract

A foundation (10) for a structure including a body (1) for insertion into a soil (2) in an insertion direction during installation, the body (1) having a toe (3) at its distal end. An array of nozzles (6) are provided at the distal end for jetting a fluid, with the nozzles (6) in the array being configured such that their fluid jets (7) are complementarily directed for generating a fluid stream (8) ahead of the toe (3) which flows in a direction perpendicular to the insertion direction to erode the soil below the pile toe.

Description

Foundations for structures and methods of installation

The present invention relates to a foundation for a structure and a method for its installation. In particular, the invention relates to structural foundations, such as piles, pipe piles, monopiles, jacket piles, suction tubes, etc., which can be inserted into the soil for supporting structures such as buildings, walls, offshore structures and wind turbines. suction bucket/caisson foundations and suction anchors, skirted foundations, sheet walls, berthing dolphins and other types of temporary and permanent shallow water or deep water foundation. The invention is particularly suitable for offshore foundations, and more particularly for open-ended tubular foundation types, such as monopiles, jacket piles and suction cans, and most particularly for offshore wind turbine foundations.

Structural foundations are typically installed by driving the foundation downward into the soil in an insertion direction and forcing it into the ground by subjecting it to a series of axial impacts using a piling or hydraulic hammer. After it is installed, the foundation moves in the axial direction through friction applied to the lateral surfaces of its body and, to a smaller extent, resistance to further penetration by the toe of the foundation. is supported.

In traditional installation techniques, the toe at the end of the foundation moves away from the soil as it is driven downward. This compresses the soil within the surrounding area. However, as the foundation is driven deeper, the pressure increases, and so does the force required to continue to move soil at the toe of the foundation. At the same time, the area of the lateral surface of the foundation in contact with the soil increases, resulting in an increase in the shear force required to overcome the driving frictional resistance. Therefore, the deeper the foundation is installed in the soil, the greater the resistance it will endure.

In recent years, there has been a trend towards the use of larger monopiles and other types of foundations, which exacerbates the above installation challenges. For example, driving a larger foundation will require greater impact force and/or more hammer strokes. On the contrary, this has greatly increased the requirements for the foundation's resistance to failure. At the same time, the noise generated by larger impacts also increases, causing significant environmental and safety hazards.

In view of the above problems, various methods and systems have been proposed to make the installation base easier. For example, electro-osmosis has been proposed as a mechanism to reduce shaft resistance during pile driving by attracting pore water towards the foundation body. This lubricates the interface between the soil and the foundation surface. However, while research in this area is ongoing, electroosmotic flow may not be suitable for all situations. Therefore, there is still a need in the industry for other methods or systems to reduce installation resistance during the installation of foundations.

Therefore, the present invention seeks to solve the above-mentioned problems.

According to a first aspect, a foundation for a structure is provided, including: a body for inserting into the soil along an insertion direction during installation, and a toe at the end of the body; and an array of nozzles, arranged at the end for ejecting a fluid, wherein the nozzles in the array are configured such that their fluid jets are complementary directed to create a fluid flow in front of the toe along a generally vertical flow in the direction of insertion.

In this way, the invention provides a foundation that can be installed more easily. Specifically, the creation of a fluid flow driven by a high pressure jet from a nozzle provides a high velocity flow that can erode soil as it moves around a fluid channel formed in a plane in front of the toe. When soil erodes, coarse particles accumulate in suspension, increasing its abrasiveness and further intensifying the erosion effect. Therefore, the toe can gradually advance into the cavity formed by the flowing fluid. At the same time, by continuous flow The excess soil suspension caused by the mass inflow is pushed upward through the gap created by this abrasive suspension flow between the foundation wall and the soil. In this way, soil particles are continuously sent away from the installation front. Importantly, since the fluid flow is perpendicular to the installation direction and the complementary arrangement of the nozzles serves to increase the fluid flow velocity, erosion of the fluid chamber wall is controlled and rapid. This contrasts with traditional jetting technology, which relies on high-power vertical jets to mechanically cut into and break up the soil. Embodiments of the invention thus allow for both improved installation speed and preservation of the surrounding soil structure to provide more stable support for the foundation after it is installed.

In some embodiments, when fluid flows through a fluid channel in a direction perpendicular to the insertion direction, the fluid flow forms the fluid channel in front of the toe in a plane perpendicular to the insertion direction by eroding soil.

In some embodiments, soil is gradually eroded from the wall of the fluid channel as the toe advances along the insertion direction during installation.

In some embodiments, the nozzles in the array are configured to create a fluid flow that flows in a circulation path in the soil region in front of the toe. In this way, the fluid flow can form a continuous loop, such that the fluid flow is driven at high speed by nozzles in a corresponding array, with each nozzle feeding into the flow generated by the preceding nozzle.

In some embodiments, the circulation path is a circumferential path coaxial with the body. In this way, when the foundation is advanced in the installation direction, the fluid channel cavity formed by the fluid flow is aligned with the foundation body to form a space between the soil and the body.

Preferably, the foundation is a hollow foundation. More preferably, the foundation is a hollow pile foundation. Even more preferably, the foundation is a single pile. For example, the monopile may have a hollow tubular body.

In some embodiments, the foundation further includes a second array of nozzles disposed at the tip, wherein the nozzles in the second array are configured such that their fluid jets are complementary directed to precede the toe. A second fluid flow is produced, the second fluid flow is along a direction perpendicular to the insertion direction and is consistent with the first flow Body fluids flow in opposite directions. In this way, the nozzles of the second array may be arranged so that their injection thrust is exerted in an opposite direction to the thrust exerted by the first array of nozzles. Therefore, this cancels out the torque exerted by spraying in the same direction. At the same time, the creation of a second flow allows for the formation of wider cavity areas to create space between the soil and the foundation body.

In some embodiments, a first array of nozzles is disposed on the inner side of the body for producing a first fluid flow in a path consistent with an interior lateral surface of the body, and a second array of nozzles is disposed on on the outside of the body for generating a second fluid flow in a path consistent with the outer lateral surface of the body. In this manner, the angle of the nozzles in each of the first and second arrays, respectively, may be directed to create a space between the soil and the inner and outer lateral surfaces of the base body.

In some embodiments, a fin is disposed at the end to separate the first fluid flow from the second fluid flow. This results in improved efficiency since less jet energy is consumed by the turbulent interface between opposing flows. At the same time, the individual nozzles in each array can be tilted closer together, thereby providing a narrower combined fluid channel cavity, which in turn allows the soil structure around the base body to be better preserved.

In some embodiments, the base further includes a manifold at an end of the base, and wherein the nozzles are secured to the manifold to be supplied with fluid. In this way, pressurized fluid can be supplied to the nozzles at the end of the base, with the shape of the manifold defining the shape of the path of the fluid channel cavity formed during spraying. That is, the shape of the manifold in a horizontal plane determines the shape of the fluid channel in the horizontal plane. At the same time, the applied pressurized fluid is used to maintain the shape of the bore within the manifold itself.

In some embodiments, the nozzles are directed downwardly about a radial axis within a range of 1 to 40 degrees from the tangential direction. Preferably, the nozzles are oriented within 10 to 30 degrees from the tangential direction. In this way, the fluid ejected from the nozzles in each array is not directed into the soil in front of the toe, but is directed obliquely downward to drive a flow of fluid suspension in the transverse plane. For example, for a circle In terms of basis, the fluid suspension flow is driven in the circumferential direction. In some embodiments, the nozzles are oriented at an angle ranging from -10 to +10 degrees from the tangential direction about the axial axis.

In some embodiments, the nozzles are distributed around the circumference of the toe. In this way, the velocity of the fluid flow created by the fluid jet can be maintained throughout the fluid circuit to provide uniform soil erosion.

In some embodiments, the base further includes a pressurized fluid supply to supply pressurized fluid to the nozzles. Preferably, the pressure of the pressurized fluid supply is 10 bar above the ambient fluid pressure. More preferably, the fluid pressure is 100 bar above ambient. Preferably it is 200 bar higher than the ambient fluid pressure.

In some embodiments, the nozzles have a diameter of 1.5 to 5 millimeters (mm). It can be understood that the larger the nozzle diameter, the greater the flux. In a preferred embodiment, the diameter of the nozzles is 2.8 mm. In such embodiments, the fluid may be supplied at a pressure of approximately 250 bar. Such an embodiment could be implemented with a monopile having two rows of nozzles pointing in different directions, each nozzle being 15/9 mm in diameter apart.

In some embodiments, the foundation further includes a controller to control one or more of the following: installation speed, ballast weight, fluid pressure of fluid supplied to the nozzle.

Preferably, the fluid contains water. For example, the fluid may be seawater, an aqueous solution, or an aqueous suspension. In this regard, a controller may be provided to control the pressure, flow rate and/or composition of the fluid delivered through the nozzle.

In some embodiments, the base further includes an additive delivery system to deliver additives to the fluid stream. For example, abrasion-increasing additives may be introduced into the fluid stream to enhance soil erosion. These additives can be introduced into the fluid supply system or via a separate delivery path. For example, it is conceivable that wear-increasing additives such as coarser particles, fine gravel or steel shot could be deposited on the seabed near the pile walls before or during installation. Then, when the erosion front As the erosion front progresses downward, these additives can trickle down the annulus to the erosion front to enhance soil erosion.

According to a second aspect of the present invention, a method for installing the above-mentioned foundation is provided. The method includes the following steps: inserting a toe into the soil; supplying fluid to the nozzles of the array to spray the fluid in front of the toe. generating a fluid flow flowing in a direction perpendicular to the insertion direction; and controlling movement of the body in the insertion direction to maintain a fluid channel formed by the fluid flow as the toe advances in the insertion direction.

In some embodiments, the method further includes a step of supplying the fluid to the second array of nozzles to generate the second fluid flow in front of the toe, the second fluid flow along a direction perpendicular to the insertion direction. and flows in a direction opposite to the direction of the first fluid flow.

1: Ontology

2:Soil

3: Manifold

4: Fluid channel

5: Lateral extension

6:Nozzle

6a, 6b: Nozzle, nozzle array

7: Fluid jet

8,8a,8b: fluid flow, flow

9:Particles

10:Basics

12:Crane

13: Test load

21: Tip, axial axis

22: Radial axis

23: Tangential direction

24:Injection direction

25:Injection angle

31:Fins

Illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of one end of the base of the first embodiment of the present invention;

Figure 2 is an enlarged isometric view of a portion of the fluid manifold shown in Figure 1 during fluid ejection;

Figure 3 is a cross-sectional plan view of a portion of an array of nozzles and associated fluid flows in the first embodiment of the present invention shown in Figure 1;

Figure 4 shows a schematic diagram for explaining the injection angle of the nozzle;

Figure 5 shows the sequence for installing the foundation shown in Figure 1; and

Figure 6 shows a cross-sectional view of one end of the base of the second embodiment of the present invention.

Figure 1 is a cross-sectional view of an end region of the base of the first embodiment of the present invention. In this embodiment, the foundation 10 is a monopile.

The foundation 10 includes a hollow tubular body 1 . The body 1 has an outer lateral surface and an inner lateral surface, and the inner lateral surface defines a hole-like internal cavity. The end of the body 1 forms a toe, which includes a manifold 3 for supplying a plurality of nozzles 6 with spray fluid. The manifold 3 is fed by a pressurized fluid supply (not shown) which delivers pressurized fluid to the end of the foundation 10 , for example from a pump provided on a nearby installation vessel. . Generally speaking, the fluid supplied via the manifold 3 is seawater.

Each nozzle 6 is supported on a lateral extension 5 extending outwardly from the manifold 3 . The lateral extension 5 contains an internal fluid channel 4 connected between the interior of the manifold 3 and the outlet of each nozzle 6 . In this way, pressurized fluid from the manifold 3 can be sprayed through the nozzle 6 .

In this embodiment, the nozzles 6 are arranged in two arrays, wherein an inner group of nozzles 6a is disposed on the inner lateral surface side of the body 1, and an outer group of nozzles 6b is disposed On the outer surface side of the body 1 . The nozzles 6 of each array are distributed circumferentially around the manifold 3 so that they are evenly spaced around the end of the body 1 . In this regard, FIG. 2 shows an enlarged isometric view of a portion of the fluid manifold shown in FIG. 1 during fluid ejection. In this figure, two of the set of outer nozzles 6b are most visible, while the set of inner nozzles 6a located on the opposite side is visible at the back of the lateral extension 5 . As shown, the nozzles 6 within each array are angled to direct their fluid jets 7 diagonally downward and in the direction of the flow of adjacent fluid jets. In this way, all nozzles 6 within each of the inner and outer arrays are evenly angled in a complementary configuration.

The above arrangement is more clearly illustrated in Figure 3, which shows a cross-sectional plan view of a portion of an array of nozzles 6 and the associated fluid flow resulting therefrom. It will be appreciated that there is also an oppositely directed flow produced by another array of nozzles. As shown, each nozzle 6 produces a fluid jet 7 when supplied with pressurized fluid via the manifold. As the injected fluid travels diagonally downward and away from each nozzle 6, it spreads and dissipates into a fluid suspension beneath the base toe. The diagonal tilt of nozzle 6 to fluid jet 7 means that instead of cutting into the soil beneath the foundation, each jet feeds diagonally under adjacent nozzle 6 in a square fluid suspension. Thus, in use, this drives the fluid suspension in a plane substantially perpendicular to the direction of insertion and thereby creates a high velocity circulating fluid flow 8 below the respective nozzle array. This flow 8 flows in the path defined by the manifold 3 in the direction of injection. In an embodiment, a flow rate of 30 m/s can be generated. Therefore, the nozzles 6 of each array form a high-speed circulating fluid annulus that is coaxial with the body 1 . As shown in Figure 2, the inner and outer nozzle arrays 6a, 6b have nozzles angled in different directions so that their respective fluid streams 8a, 8b will also flow in opposite directions. This configuration of generating opposite flows serves to counteract the torsional moments that would otherwise be exerted on the ends of the base body 1 if the jet thrust from all nozzles were directed in the same direction of rotation.

As shown in Figure 1, in this embodiment the inner and outer nozzles 6a and 6b are also slightly tilted outwards away from each other, so that the fluid flows 8a and 8b thus generated are separated. That is, the nozzles 6a and 6b are angled so that the tip 21 of the soil 2 below the manifold 3 will remain between the two streams 8a and 8b, thereby avoiding mutual interference between them.

FIG. 4 shows a schematic diagram for explaining the spray angle of the nozzle in more detail. As shown, the base body 1 defines an axial axis 21 coinciding with the direction of insertion of the base. Perpendicular to this is the radial axis 22 of the body 1 and the tangential direction 23 is also shown. In this embodiment, the nozzle is tilted in the injection direction 24 at an injection angle 25 which is 20 degrees lower than the tangential direction of rotation about the radial axis 22 . In other embodiments, the injection angle 25 may be from 0 to 40 degrees, and preferably from 10 to 30 degrees. As mentioned above, the nozzle may also be slightly tilted outwards or inwards, for example at an angle of -10 to +10 degrees about the axial axis 21.

In use, as shown in Figure 1, when the base body 1 is driven into the soil, particles 9 from the soil will be suspended in the fluid streams 8a, 8b. The fluid streams 8a, 8b thus contain a suspension of abrasive soil particles flowing at high speed in two concentric rings with opposing flows formed by the inner and outer nozzle arrays 6a, 6b. In this way, the fluid flows 8a, 8b accelerated by the fluid jet 7 have an abrasive effect on the underlying soil 2, causing more soil particles to detach from the walls of the fluid channel. When the toe of base 10 is deep This has the effect of maintaining space for the fluid flow 8a, 8b when penetrating into the soil 2. As a result, the soil 2 is quickly eroded away before the foundation 10, allowing the foundation 10 to move down through the soil more easily.

In this regard, Figure 5 shows the sequence for installing the foundation 10 in an offshore location. As shown in Figure 5(a), the foundation 10 is lowered through the water 10 so that its end is inserted into the soil 2. Before joining the seabed, the fluid jet 7 starts ejecting, but at a relatively low pressure, for example 50 bar. This initial spray prevents soil from entering the spray system. After the foundation toe contacts the seabed, it penetrates downward to the initial depth under its own weight. The depth may be, for example, approximately 2 meters.

Once the initial depth is reached, the fluid injection pressure is increased to 300bar. As shown in Figures 5(b) and 5(c), as the high-pressure injection is established, the toe of the foundation 10 penetrates the soil 2 axially downward along the insertion direction. As mentioned above, the water jet is used to accelerate the flow of the soil suspension located under and around the toe of the body 1, forming at least one fluid channel cavity with a high-speed circulating flow stream. These flows 8 around the circumference of the toe area are loaded with suspended abrasive soil particles and serve to erode the walls of the fluid channel. This thereby forms a ring on either side of the body 1 which separates the soil from the inner and outer surfaces of the foundation. The excess soil suspension caused by the continuous fluid inflow through the spray nozzle 6 also creates an upward fluid flow through the gap formed between the body wall and the soil. The soil is thus transported onto the foundation body. These combined effects result in a significant reduction in frictional resistance during foundation installation.

The insertion speed may be controlled, for example, by controlling the rate at which the crane 12 lowers the foundation 10. For example, an installation rate of two meters per minute (2m/min) could be maintained during this installation phase. Often the weight of the foundation itself is enough to drive the toe down. However, in some cases, a ballast (not shown) may be attached to the proximal end of foundation 10 to aid drive installation.

In this regard, the dimensions of the fluid channel cavity formed by the fluid jet 7 may vary depending on the erosiveness of the soil and the speed of foundation installation. If the installation speed is too fast, the cavity may become so small that the suspension flow eventually becomes immobilized and the erosion rate decreases. In this case, the installation speed can be reduced or stopped to allow new cavities to form and the suspension flow to develop. For example, in use, if you are driving If a rapid increase in installation resistance is detected during the dynamic phase, the crane 12 can be used to stop the installation and lift the foundation by, for example, 10 cm before restarting the lowering process of the piles. This thereby raises the foundation to create space to re-establish the fluid flow 8, allowing their grinding action to resume. This may occur, for example, when conditions change from granular soil to more cohesive soil during installation. When the toe penetrates the clayey soil layer, the erosion will be reduced, otherwise a runaway effect may occur. By quickly reducing the installation rate, circumferential flow can be avoided from stalling, and once through the more viscous layer, the installation rate can be gradually increased to return to the optimal rate. It should be understood that if the installation speed is too fast for the crane 12 or associated mechanism, the injection pressure may be reduced.

As shown in Figure 5(d), once the foundation 10 reaches a predetermined depth threshold slightly ahead of the target depth, the fluid jet 7 may be shut down. For example, the predetermined depth threshold may be 30 centimeters above the target depth. This thereby minimizes disturbance of the soil at the target depth, allowing the foundation 10 to sink to its final target depth without unduly weakening the soil structure in this area. Once the target depth is reached, the foundation 10 will prevent further installation. Once the insertion phase is complete, the soil 2 will relax to refill the space created by the fluid flow. As shown in Figure 5(e), a test load 13 may then be applied to verify the initial axial load carrying capacity of the foundation 10. Over time, the axial load-carrying capacity of the foundation will gradually increase as the load cycles of wave loads act, thereby re-compacting the soil in the annulus formed by the fluid flow.

Figure 6 shows a cross-sectional view of the end of a foundation according to a second embodiment of the invention. This second embodiment is essentially the same as the first embodiment, but the toe of the base 10 is also provided with fins 31 for separating the inner and outer fluid flows 8a, 8b. Fins 31 serve to separate opposing suspension flows to avoid interference between them. This may thereby allow the respective nozzles of each array to be angled more closely together, thereby providing a narrower combined fluid channel cavity. This allows the soil structure around the foundation body to be better preserved. At the same time, it also improves efficiency because the turbulent interface between opposing flows consumes less jet energy.

As will be appreciated from the above, the inventive arrangements disclosed herein allow for easier installation of foundations into the soil. This reduces costs and allows installation noise to be minimized.

In this regard, with embodiments of the present invention, the soil failure mechanism at the toe of the foundation can be sustained throughout the pile installation process as the foundation penetrates deeper. Therefore, no piling or large ballast is required to achieve the target installation depth. After the foundation is installed to the desired depth, the fluid injection system can be turned off to allow water to drain from the soil around the foundation body. Suspended soil particles will then settle to form sediments, which may become compacted over time through a cyclic shake down effect, thereby re-stabilizing soil strength.

Importantly, because the fluid jet is used to create a fluid flow that erodes the soil, rather than cutting directly into the soil itself, the soil structure outside the resulting fluid channel is essentially undisturbed, and the suspension pressure acts to stabilize the adjacent soil. Therefore, this soil is able to maintain its structure in supporting the foundation. This contrasts with traditional liquid excavation techniques, which use pressurized liquid to cut into the soil to excavate space for foundations. With this traditional method, soil is removed in an uncontrolled manner and once the foundation is in place, the excavated site is effectively refilled with reclaimed soil. However, since the soil that refills the space is newly located, it will have low structural development and will therefore be inherently weaker.

It should be understood that the above-described embodiments illustrate the application of the invention for illustrative purposes only. Indeed, the invention may be applied in many different configurations and the detailed embodiments will be readily apparent to those skilled in the art.

For example, it should be understood that by adjusting the spray direction of the nozzle, the position and shape of the fluid channel formed under the toe can be adjusted. For example, by positioning the nozzle inside the base, the fluid chamber will be moved further into the base body. Instead, by positioning the nozzles on the inside and outside, and placing them slightly further away from the base wall, the suspension flow can form a wider cavity, or it can form two separate cavities, as shown in Figure 1.

Additionally, in some embodiments, additives may be added to the fluid flow formed at the base toe, such as by introducing the additive into a fluid supply or separately using an additive delivery system. For example, abrasive additives can be used to introduce rougher/angled material to improve the abrasiveness of the fluid stream. This may be advantageous when dealing with non-erodible soil types such as silt, clay, chalk, soft bedrock. Grout can also be introduced at the end of the installation process to improve the in-place performance of the foundation.

It should also be understood that additional mechanisms and systems may be used in conjunction with the described fluid injection system to further reduce drive resistance. For example, the base may further contain electrodes for electroosmotic flow. Additionally, fluid injection systems can work in conjunction with electroosmotic flow systems.

Finally, although in the above illustrative embodiment the foundation is a monopile, it should be understood that other foundations are possible, such as bucket foundations.

1: Ontology

2:Soil

3: Manifold

4: Fluid channel

5: Lateral extension

6a, 6b: Nozzle, nozzle array

7: Fluid jet

8a,8b: fluid flow, flow

9:Particles

10:Basics

21: Tip, axial axis

Claims (15)

A basis for structure, including: A body for insertion into the soil in an insertion direction during installation, the body having a toe at its end; and An array of nozzles is disposed at the end for ejecting a fluid, wherein the nozzles in the array are configured such that their fluid jets are complementary directed to create a fluid flow in front of the toe, the fluid The flow flows in a direction generally perpendicular to the direction of insertion. The foundation of claim 1, wherein when the fluid flows through a fluid channel in the direction perpendicular to the insertion direction, the fluid flow erodes soil at the toe in a plane perpendicular to the insertion direction. The fluid channel is formed in front of the part. The foundation of claim 2, wherein when the toe advances along the insertion direction during installation, the soil gradually begins to be eroded from the wall of the fluid channel. The basis of claim 1, wherein the nozzles in the array are configured to generate the fluid flow along a circulation path in a soil area in front of the toe. The basis of claim 4, wherein the circulation path is a circumferential path coaxial with the body. The basis of claim 1, further comprising a second array of nozzles disposed at the end, wherein the nozzles in the second array are configured such that their fluid jets are complementary directed to form at the toe A second fluid flow is generated in front, and the second fluid flow flows in a direction perpendicular to the insertion direction and opposite to the first fluid flow. The basis of claim 6, wherein the first array of nozzles is disposed on the inside of the body for generating the first fluid flow in a path consistent with an interior lateral surface of the body, and The second array of nozzles is disposed on the outside of the body for generating the second fluid flow in a path consistent with the exterior lateral surface of the body. The foundation of claim 6, further comprising fins disposed at the end to separate the first fluid flow and the second fluid flow. The foundation of claim 1, further comprising a manifold located at the end of the foundation, and wherein the nozzles are secured to the manifold to be supplied with fluid. The basis of claim 1, wherein the nozzles are directed downward around a radial axis in a range of 1 to 40 degrees from the tangential direction. The basis of claim 1, further comprising a pressurized fluid supply device for supplying pressurized fluid to the nozzles. The basis of claim 1, further comprising a controller to control one or more of the following: installation speed, ballast weight, and fluid pressure supplied to the nozzles. The basis of claim 1, further comprising an additive delivery system for delivering additives to the fluid stream. A method of installing a foundation as described in any one of claims 1 to 13, the method comprising: Insert the toe into the soil; supplying the fluid to the nozzles of the array to eject the fluid to create a flow of the fluid in front of the toe in a direction perpendicular to the insertion direction; and As the toe advances along the insertion direction, movement of the body in the insertion direction is controlled to maintain a fluid channel formed by the fluid flow. The method of claim 14, when dependent on claim 7, further comprising the step of supplying the fluid to the nozzles of the second array to generate the second fluid flow in front of the toe, the second fluid flow Flow in a direction perpendicular to the insertion direction and opposite to the first fluid flow.