Excavation tool and method of installing a foundation using the same

Abstract

Excavation tool (10) for use during installation of a foundation (100) into soil (200) in an insertion direction (11). The excavation tool comprises a body (12), an engagement surface (18) provided on the body (12) for releasable engagement with the foundation (100) for driving the body (12) into the soil (200) in the insertion direction (11); and a plurality of nozzles (38) provided on the body for jetting a fluid.

Description

[0001] The present disclosure concerns an excavation tool and a method of installing a foundation using the same excavation tool. In particular, the present disclosure concerns the installation of structural foundations, such as piles, tubular piles, monopiles, jacket piles, suction bucket / caisson foundations and suction anchors, and skirted foundations that may be inserted into a soil for supporting structures such as buildings, offshore structures, and wind turbines. The present disclosure is particularly relevant to offshore foundation installation, and more particularly to the installation of open ended tubular offshore foundations, and most particularly monopiles and monopiles for wind turbines.

[0002] Structural foundations are typically installed by forcing the foundation into the ground in an insertion direction. This may be achieved, for example, by applying a weighted ballast to the proximal head of the foundation, applying a vibratory hammer, or using a pile hammer to apply a series of axial impacts to drive the foundation's toe down into the soil. Once installed, the foundation is axially supported by the friction applied to the lateral surfaces of the foundation's body and the resistance to further penetration at the foundation's toe.

[0003] During installation, the toe at the distal end of the foundation displaces soil as it is driven down. This compresses the soil in the surrounding region. However, as the foundation is driven deeper, and pressure increases, the forces required to continue displacing soil at the foundation's toe also increase. At the same time, the surface area of the foundation in contact with the soil increases, leading to an increase in the shear forces required to overcome the frictional resistance to driving. As a result, the load bearing capacity of the foundation increases as the foundation is installed deeper into the soil.

[0004] In recent years, there has been a trend towards having larger monopiles and other foundations, and this has exacerbated the challenges associated with their installation. For example, higher impact forces and / or a higher number of hammer strikes are required for pile driving larger foundations. This in turn imposes significant failure resistance requirements on the foundation. At the same time, the noise generated by the larger impacts is also increased, which presents significant environmental and safety hazards.

[0005] In view of the above, various methods and systems have been proposed for making the installation of foundations easier.

[0006] In this connection, one solution involves the use of liquid excavation techniques, which not only facilitate easier installation, but may also help to minimise noise emissions. With such arrangements, high pressure nozzles are used to jet liquid for cutting into and flooding the body of soil around the toe in order to fluidise the soil and excavate space for the foundation.

[0007] Although conventional jetting methods are effective at aiding the driving of the foundation, this is therefore often to the detriment of the bearing load of the resultant installation. As such, there has been efforts to find alternative solutions. For example, one solution is described in WO2019 / 206690 where nozzles on the interior of the foundation are used to direct fluid laterally into a soil region displaced inward by the foundation's toe. This thereby allows targeted fluidisation of the soil compressed by the advancing toe, and hence minimises disturbance of the exterior soil structure.

[0008] However, one issue with the above solutions is that they require specialised foundations with integrated jetting systems. This makes manufacture of foundations more complex which, in the case of large foundations such as monopiles, significantly increases their cost.

[0009] The present invention therefore seeks to address the above issues with the prior art.

[0010] According to a first aspect of the present invention, there is provided an excavation tool for use during installation of a foundation into soil in an insertion direction, the excavation tool comprising: a body; an engagement surface provided on the body for releasable engagement with the foundation for driving the body into the soil in the insertion direction; and a plurality of nozzles provided on the body for jetting a fluid.

[0011] In this way, a jetting system may be provided for use with a standardised foundation which does not include an integral jetting system. This may thereby provide the advantages associated with jetted foundation installation, whilst at the same time providing cost savings in foundation design and improved flexibility in deployment and use. For example, the fluid jetted from the plurality of nozzles may act to cut into a region of soil distally below the toe of the foundation for forming a channel into which the foundation may then be received. This may thereby reduce installation resistance during the main driving phase of the foundation's installation. In addition, the excavation tool can be used for various types of foundations and in different soil conditions to install the foundation. Furthermore, as mentioned above, installation costs can be reduced by providing an excavation tool as a separate part to the foundation.

[0012] In embodiments, the foundation is a monopile comprising a toe and the body has a shape in a lateral plane corresponding to the toe. In this way, the toe and the body may have substantially the same footprint so that they can mate with each other when fitted together. In this way, the excavation tool can be used to facilitate the installation of monopiles, such as wind turbine monopiles used for supporting wind turbine generators offshore. The shape of the excavation tool can allow it to engage with the toe of the foundation. While the shape of the excavation tool across an interface surface may substantially be the same as the shape of the toe of the foundation, the size of the excavation tool can also be varied, such that the excavation tool can be fitted in, around or on the toe, or offset from the toe of the foundation.

[0013] In embodiments, the engagement surface is configured to be engaged by the toe of the foundation. In this way, the excavation tool may be configured to mate to the distal end of the monopile for generating an annulus into which the monopile body is inserted.

[0014] In embodiments, the foundation comprises a hollow interior and the engagement surface is configured to releasably engage an interior lateral surface of the hollow interior at a distal end of the foundation or offset from the distal end by a distance.

[0015] In embodiments, the engagement surface is configured to releasably engage an exterior lateral surface of the foundation at a distal end of the foundation or offset from the distal end by a distance.

[0016] In embodiments, the plurality of nozzles are distributed around an inner surface or a bottom surface of the body. In embodiments, these may include an interior array of nozzles mounted to an interior circumference of the body and / or an exterior array of nozzles mounted to an exterior circumference of the body. In this way, nozzle arrays may be provided corresponding to the toe of the monopile foundation.

[0017] In embodiments, the plurality of nozzles comprise a plurality of nozzles configured to jet the fluid in an insertion direction ahead of the foundation. In this way, the plurality of nozzles may be directed to cut into the soil immediately ahead of the foundation in the insertion direction. This results in a decreased installation resistance as the soil ahead of the foundation is excavated.

[0018] In embodiments, the plurality of nozzles may comprise nozzles directed substantially tangentially with respect to a circumference of the body. In this way, the plurality of nozzles generate a rotating soil suspension within the channel that aids to excavate the region of soil distally below the toe of the foundation. This may provide decreased installation resistance by fluidising the soil and minimising soil compaction.

[0019] In embodiments, the engagement surface is configured to be engaged by a toe end of the foundation. In this way, the excavation tool may connect to the distal end of a foundation such that it sits beneath the foundation as it is driven into the soil. In embodiments, the engagement surface is configured to attach to the toe end of the foundation. In this way, the separate excavation tool and foundation may be fixed together to form an assembly, which may thereby prevent the excavation tool from becoming separated from the toe during monopile installation.

[0020] In embodiments, the excavation tool further comprises an alignment formation for aligning an engagement region of the foundation with the engagement surface. In this way, engagement between the excavation tool and the foundation may act to force these parts into alignment as they are driven together.

[0021] In embodiments, the engagement region of the foundation is the foundation's toe, and the alignment formation is for guiding the body to align with the foundation.

[0022] In embodiments, the alignment formation comprises an inclined guide surface for guiding the body to align with the foundation. In this way, the inclined guide may gradually move the parts into alignment as they are forced into engagement with one another.

[0023] In embodiments, the alignment formation comprises one or more expansion slots for accommodating different toe sizes of the foundation. In this way, the excavation tool can engage with a variety of foundations with varying toe sizes.

[0024] In embodiments, the alignment formation comprises a foldable member configured to fold towards the foundation once engaged for coupling the body to the foundation. In this way, the alignment formation may be used to lock the excavation tool and the foundation into an aligned coupling.

[0025] In embodiments, the excavation tool further comprises a locking mechanism for locking the body to the foundation. In this way, the excavation tool and the foundation can be locked together for preventing disengagement between these bodies. In embodiments, the locking mechanism comprises at least one of a latch, a friction fit, a pressure fit, and a press fit. In embodiments, the locking mechanism may form a water-tight connection between the body and the foundation. Such embodiments are particularly helpful in scenarios where the internal water table is controlled for controlling the suspension pressure.

[0026] In embodiments, the body comprises one or more internal chambers for feeding fluid to the plurality of nozzles. In this way, pressurised fluid may be supplied to the body, allowing it to act as a manifold for supplying the nozzles and helping to maintain its structural integrity under the installation load.

[0027] In embodiments, the body further comprises an inlet for receiving a high-pressure fluid for supplying the plurality of nozzles. In embodiments, the inlet comprises a decoupling mechanism for decoupling a high-pressure supply hose. In other embodiments, the decoupling mechanism feature is provided on the high-pressure supply hose. In this way, the umbilical used to supply high pressure fluid to the body may be decoupled, for instance, at mudline level after installation. In other arrangements, the decoupling mechanism comprises a guillotine for severing the hose at mudline. This may be provided as a redundancy if the de-coupling at the inlet port fails.

[0028] In embodiments, the engagement surface further comprises an activator for activation when the engagement surface is engaged by the foundation. In some embodiments, this activator may comprise a sensor for detecting the engagement of the foundation. In embodiments, the activator may be a mechanical activator. Such a mechanical activator may be used, for instance, to open a valve for activating the nozzles or to actuate a latching mechanism for locking the tool to the foundation.

[0029] According to a further aspect of the invention, there is provided a method of installing a foundation using an excavation tool according to any one of the above statements, the method comprising: engaging the excavation tool with a foundation at an engagement surface; driving the body into the soil in the insertion direction using the foundation; and jetting fluid from the plurality of nozzles.

[0030] In embodiments, the method further comprises the step of detaching a fluid supply pipe from the body once a predetermined depth in the installation direction has been reached.

[0031] In embodiments, a controller is further provided for controlling jetting from the nozzles.

[0032] Illustrative embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows an isometric view of an excavation tool according to a first illustrative embodiment; Figures 2A-2C shows cross-sections of excavation tools according to various embodiments having different arrangements of nozzles; Figure 3 shows an isometric view of an excavation tool according to a further illustrative embodiment with a plurality of nozzles directed in a tangential direction; and Figure 4A-4E shows an installation process for a foundation using the excavation tool.

[0033] Figure 1 shows an excavation tool 10 of a first illustrative embodiment. The excavation tool 10 is provided as a body separate to a foundation and can be used during the installation of the foundation. In the illustrative embodiments described in this application, the foundation 100 is a monopile comprising a hollow tubular body 102 having an exterior lateral surface 104, and an interior lateral surface 106 that defines an interior cavity 108 in the form of a bore. However, it is to be understood that other foundations are suitable for use with the excavation tool 10. The excavation tool 10 is sized and shaped to cooperate with the hollow body of the foundation, as described in more detail below. The interior lateral surface 106 defines an opening 110 into the interior cavity 108 of the foundation 100. A distal end 112 of the foundation 100 comprises a toe 114 for insertion into the soil 200 at the seabed 202 in an insertion direction (e.g. see Figures 4a-4e). During installation a proximal end 116 of the foundation 100 is supported by an external structure, or foundation installation vessel. In embodiments of the present invention, the foundation 100 is an offshore wind turbine monopile for supporting a wind turbine.

[0034] The excavation tool 10 comprises a body 12 adapted to receive the toe 114 of a foundation 100 for foundation installation. In particular, in some embodiments, the excavation tool 10 may be first lowered onto the soil 200 at the seabed 202. Subsequently, the foundation 100 is lowered onto and aligned with the body 102 of the excavation tool 10. In other embodiments, the excavation tool may be premounted to the foundation, for instance in the harbour or immediately prior to its lowering into the sea. In embodiments, the body 12 may have a polygonal, circular, elliptical, or compound cross section. The body 12 comprises a central aperture 14 that is configured to substantially correspond to the cross-sectional area of the opening 110 at the toe 114 of the foundation 100. That is, the central aperture 14 has a diameter that substantially matches the diameter of the opening 110 at the toe 114 of the foundation 100. As the foundation 100 is driven into the soil 200 during installation, a coaxial assembly is formed between the bodies with the central aperture 14 and the opening 110 being coaligned such that soil 200 can pass through the central aperture 14 and into the internal cavity 108 through the opening 110.

[0035] In embodiments, the shape of the body 12 is configured to substantially correspond to the shape, or cross section, of the toe 114 of the foundation 100. In one embodiment, the size of the body 12 is larger than the size of the toe 114, such that the body 12 is configured to be installed on the exterior lateral surface 104 around the distal end 112 or offset from the distal end 112 by a distance. In alternative embodiments, the size of the body 12 is smaller than the size of the toe 114, such that the body 12 is configured to be installed on the interior lateral surface 106 around the distal end 112 or offset from the distal end 112 by a distance.

[0036] The body 12 may comprise an alignment formation 16 provided on a top surface 18, or engagement surface, of the body 12 for aiding the alignment of the toe 114 of the foundation 100 with the body 12. The alignment formation 16 may be provided as a continuous tapered ridge that runs along the top surface 18 of the body 12. In this embodiment, the alignment formation 16 comprises two tapered ridges which together form a substantially V-shaped cross-section for guiding the toe 114 of the foundation into engagement with the toe surface 18 of the excavation tool 10. While the embodiment of Figure 1 shows a continuous alignment formation 16 provided on the top surface 18 of the body 12, it is to be understood that the alignment formation 16 may be formed of a plurality of projections that are circumferentially spaced along the top surface 18 of the body 12 for aligning the foundation 100 with the body 12. In addition, the alignment formation 16 may comprise one or more expansion slots for accommodating various toe sizes. For example, the excavation tool may comprise an open side to its engagement surface to allow for different diameters to be accommodated. For instance, there might be one or more expansion gaps provided on, for example, the opposite side of the high-pressure inlet.

[0037] Furthermore, the alignment formation 16 may be foldable such that it collapses inwards towards the lateral surfaces of the foundation 100 as the excavation tool 10 is driven into the soil 200. For example, an outer side 20 of the alignment formation 16 may fold towards the exterior lateral surface 104 of the foundation 100. In addition, or alternatively, an inner side 22 of the alignment formation 16 may fold towards the interior lateral surface 106 of the foundation 100. Accordingly, the alignment formation 16 may be separated into sections so that the sections of the alignment formation 16 may fold. Preferably, the alignment formation 16 is folded by the weight of the foundation 100 itself. In this way, the alignment formation 16 does not extend substantially beyond the profile of the body 12 once folded and hence the soil resistance is reduced. The folding action may also function as a latching mechanism for attaching the excavation tool 10 to the foundation 100, as described below.

[0038] In this respect, the body 12 in this embodiment comprises one or more latches 24 on the top surface 18. In one embodiment, as the alignment formation 16 folds inward during installation, the top edges 26 of the alignment formation 16 may couple to a bar, or an edge, located on the exterior lateral surface 104 of the toe 114 of the foundation 100 to latch the excavation tool 10 to the foundation 100. Alternatively, the one or more latches 24 may couple to the toe 114 of the foundation 100 by friction, by a pressure or press fit between the one more latches 24 and the exterior lateral surface 104 of the toe, and / or by magnets with opposite poles located in the one or more latches 24 and the toe 114 of the foundation. Once the latches 24 are coupled to the toe 114, the excavation tool 10 may be translationally and rotationally coupled to the toe 114 of the foundation 100. In an embodiment, the coupling between the excavation tool 10 and the toe 114 of the foundation 100 may be watertight, such that water is prevented from flowing through the alignment formation 16. In these embodiments, the one or more latches 24 are releasable from the toe 114 of the foundation 100, such that the excavation tool 10 can be decoupled from the toe 114.

[0039] In an embodiment, the excavation tool 10 may be coupled to the toe 114 prior to foundation installation. In a further embodiment, the excavation tool 10 may be first lowered onto the soil 200 at the seabed 202 with the foundation 100 then lowered onto and aligned with the body 102 of the excavation tool 10, such that the excavation tool 10 couples with the toe 114 of the foundation 100.

[0040] As shown in Figures 2A-2C, the body 12 of the excavation tool 10 comprises a manifold 28, or internal chamber, that forms in this embodiment a ring-like conduit around the central aperture 14. In use, the manifold 28 is pressurised by fluid fed through a fluid feed pipe 30 connected to an inlet port 32 provided on the body 12. The inlet port 32 can be provided, for example, on the interior circumference 32 or the exterior circumference 34 of the body 12. As described below, additional jets maybe provided to make space for the inlet port. In other embodiments, a plurality of fluid feed pipes and inlets 32 may be used. In a further embodiment, the body 12 of the excavation tool 10 comprises a plurality of manifolds 28 that are each pressured by a fluid at different pressures. In these embodiments, the fluid feed pipe 30 is releasably attached to the body 12, such that the fluid feed pipe 30 can be detached from the body 12 and withdrawn from the seabed once installation of the foundation 100 is complete. For example, the fluid feed pipe 30 may detach from the body 12 or at a point along the length of the fluid feed pipe 30. In other embodiments, the fluid feed pipe 30 may be connected to an interior circumference 34 of the body 12, such that the fluid feed pipe 30 passes up through the interior of the foundation 100. In these embodiments, the fluid feed pipe 30 may be a flexible pipe, such as an umbilical pipe or a hose.

[0041] The fluid feed pipe 30 may be fed by a fluid pump (not shown) under the control of a controller 36 provided on an installation vessel, another vessel or any other appropriate place (not shown). Advantageously, the pressurisation of the manifold 28 by fluid during use may help to resist its compression if, for example, the body 12 is driven into a rock in the soil 200 during installation.

[0042] The manifold 28 feeds a plurality of nozzles 38 provided on the body 12. As shown in Figures 2A-2C, the plurality of nozzles 38 may be provided on the interior circumference 34 of the body, or on the exterior circumference 32 of the body 12. In addition, the plurality of nozzles 38 may be integrally formed with the body 12 on a bottom surface 40. In alternative embodiments, the plurality of nozzles 38 may be a combination of the arrangements shown in Figures 2A-2C. In embodiments where the inlet port 32 is provided on the exterior circumference 34 of the body 12, a nozzle 38 may be provided adjacent to the inlet port 32 on the exterior circumference 32 of the body 12 to excavate a region of soil distally below the inlet port 32, such that the fluid feed pipe 30 connected to the exterior inlet port 32 can be accommodated in the soil.

[0043] In embodiments, the bottom surface 40 of the body 12 may be provided with a spud, or mud mat, for preventing the excavation tool 10 from sinking into the soil 200 when the excavation tool 10 is lowered onto the soil 200 at the seabed 202, prior to the foundation 100 being lowered onto the excavation tool 10. The mud mat is configured to fold or break off from the body 12 of the excavation tool 10 as the excavation tool 10 is driven into the soil 200 by the body 12 of the foundation 100.

[0044] The controller 36 is configured to activate the fluid pump for jetting the fluid through the nozzles 38 after the toe 114 of the foundation 100 is received into the alignment formation 16 and engages with the top surface 18 of the body 12. In embodiments, an activator or trigger 42 may be provided on the body 12 that is actuated by the weight of the foundation 100. The controller 36 may detect the actuation of the activator 42 and this may be used as a control input to activate other operations. For example, actuation of the activator 42 may activate a latching mechanism for clamping the tool to the foundation. In other embodiments, it may prime or activate the fluid supply system to enable subsequent jetting during the installation process. Alternatively, the folding of the alignment formation 16 may be detected by the controller 36. As such, alignment between the body 12 and the foundation 100 may be determined based on the engagement between these parts.

[0045] As shown in Figures 2A-2C, the nozzles 38 are fed by connectors 44, which extend into an interior conduit of the manifold 28 and contain an internal fluid channel between the plurality of nozzles 38 and the manifold 28. As such, fluid fed into the manifold 28 is jetted through the nozzles 38. Each nozzle 38 is configured to direct pressurised fluid jets downwardly ahead of the body 12 in the insertion direction. The cutting action of the jets from adjacent nozzles 38 form circumferential cuts into the soil 200 ahead of the body 12. Accordingly, a cut into the soil 200 is created by the plurality of nozzles 38, which excavates the soil 200 ahead of the body 12 and foundation 100 to reduce the force required to install the foundation 100.

[0046] In other embodiments, the nozzles 38 may be angled to generate a circumferential fluid flow in the fluid channel formed thereby. This circumferential fluid flow may thereby result in a swirling fluid flow in a lateral plane to the insertion direction, carrying with it excavated particulates which may help to excavate further soil ahead of the foundation's toe.

[0047] Figures 4A-4E show a sequence of the excavation tool 10 being deployed and the foundation 100 being installed according to an embodiment of the invention. In Figure 4A, the excavation tool 100 is lowered onto the soil 200 at an installation location by a crane located on the installation vessel. While Figure 4A shows that the excavation tool 100 is lowered onto the soil 200, it is understood from the present disclosure that the excavation tool 100 may instead be coupled to the foundation before the foundation is installed, such that the combined assembly of the excavation tool 100 and foundation 100 are both lowered together and inserted onto the soil 200. The installation vessel may be different to the foundation installation vessel used to lower the foundation 100. Beneficially, by providing two separate vessels for lowering the excavation tool 10 and the foundation 100, a first smaller, and hence lower cost installation vessel can be used to set up the installation site, with the larger vessel required for handling the monopile being deployed later. This allows for streamlining of offshore processes.

[0048] Once the excavation tool 10 has been lowered onto the seabed 202, the foundation 100 is lowered onto and aligned with the excavation tool 10, as shown in Figure 4B. The controller 36 activates the pump to generate fluid jets through the nozzles 38 when the toe 114 of the foundation 100 contacts the top surface 18 of the body 12. The controller 36 may activate the pump, for example, once the activator 42 on the body has been activated, or when the depth of the toe 114 of the foundation 100 reaches a pre-defined depth.

[0049] As shown in Figure 4C, the foundation 100 is lowered further, causing the body 12 to be driven downward into the soil 200 under the foundation's 100 own weight, by the aid of an additional ballast, or through use of a vibration hammer for vibration driving of the foundation 100. This insertion is further facilitated by the jetting from the nozzles 38. The jets act to remove the soil 200 ahead of the body 12 as the foundation 100 continues to be driven downward, thereby forming the channel 204. The channel 204 may form a deep trench extending from the jetted region ahead of the toe 2 up to the surface of the soil 200 at the seabed 202. Toe depth and installation resistance may be determined by the controller 36 based on how far the foundation 100 has been driven into the soil 200 and the rate of its advance.

[0050] Once the required installation depth is reached and jetting has been stopped, the fluid feed pipe 30 may be detached from the body 12 and withdrawn by the installation vessel. Surplus water from the jetting will drain away from the trench, and soil particles will resettle.

[0051] It will be appreciated that with the above methods and arrangements, a foundation may be installed into the soil more easily using the jetted assisted installation of the excavation tool. By using a separate, attachable, tool for enabling jetting, the number of sacrificial jetting components can be minimised, and manufacturing of the foundation can be simplified as the jetting system does not interfere with these manufacturing processes. At the same time, offshore logistics become much simpler because supporting systems, such as the high-pressure fluid supply and the associated umbilical can be handled by a separate, much smaller vessel. This also allows for redundancies and standardisation. For example, universal feeder pipe designs can be used. This reduces cost and allows installation noise to be minimised. The excavation tool may be coupled, or retrofit, to the foundation either before or during foundation installation, such that it can be coupled to a variety of foundations without modifying the design of the foundations. That is, standardised foundations may be used without needing their own integral jetting system. This provides for lower costs, whilst also allowing more complex jetting arrangements to be implemented. Moreover, some equipment such as the feed pipe may be recovered following installation to allow for re-use and lower costs.

[0052] It will be understood that the embodiments illustrated above show applications of the invention only for the purposes of illustration. In practice the invention may be applied to many different configurations, the detailed embodiments being straightforward for those skilled in the art to implement. For example, while the illustrative embodiments described in this application have been shown in conjunction with a monopile foundation having a circular cross-section, it is to be understood that the invention can also be applied to other shaped foundations, with the shape and size of the excavation tool being configured to conform that respective foundation shape.

Claims

1. An excavation tool for use during installation of a foundation into soil in an insertion direction, the excavation tool comprising: a body; an engagement surface provided on the body for releasable engagement with the foundation for driving the body into the soil in the insertion direction; and a plurality of nozzles provided on the body for jetting a fluid.

2. The excavation tool according to claim 1, wherein foundation is a monopile comprising a toe, and the body has a shape in a lateral plane corresponding to the toe.

3. The excavation tool according to claim 2, wherein the engagement surface is configured to be engaged by the toe of the foundation.

4. The excavation tool according to claim 1 or 2, wherein the foundation comprises a hollow interior and the engagement surface is configured to releasably engage an interior lateral surface of the hollow interior at a distal end of the foundation or offset from the distal end by a distance.

5. The excavation tool according to claim 1 or 2, wherein the engagement surface is configured to releasably engage an exterior lateral surface of the foundation at a distal end of the foundation or offset from the distal end by a distance.

6. The excavation tool according to any preceding claim, wherein the plurality of nozzles are distributed around an inner surface or a bottom surface of the body.

7. The excavation tool according to any preceding claim, wherein the plurality of nozzles comprise a plurality of nozzles configured to jet the fluid in an insertion direction ahead of the foundation.

8. The excavation tool according to claim 2 or 3, further comprising an alignment formation for aligning an engagement region of the foundation with the engagement surface.

9. The excavation tool according to claim 8, wherein the engagement region of the foundation is the foundation's toe, and the alignment formation is for guiding the body to align with the foundation.

10. The excavation tool according to claim 8 or 9, wherein the alignment formation comprises an inclined guide surface for guiding the body to align with the foundation.

11. The excavation tool according to any of claims 8 to 10, wherein the alignment formation comprises one or more expansion slots for accommodating different toe sizes of the foundation.

12. The excavation tool according to any of claims 8 to 11, wherein the alignment formation comprises a foldable member configured to fold towards the foundation once engaged for coupling the body to the foundation.

13. The excavation tool according to any preceding claim, further comprising a locking mechanism for locking the body to the foundation.

14. The excavation tool according to any preceding claim, wherein the body comprises an internal chamber for feeding fluid to the plurality of nozzles.

15. The excavation tool according to any preceding claim, wherein the body further comprises an inlet for receiving a high-pressure fluid for supplying the plurality of nozzles.

16. The excavation tool according to any preceding claim, wherein the engagement surface further comprises an activator for activation when the engagement surface is engaged by the foundation.

17. A method of installing a foundation using an excavation tool according to any one of claims 1 to 16, the method comprising: engaging the excavation tool with a foundation at an engagement surface; driving the body into the soil in the insertion direction using the foundation; and jetting fluid from the plurality of nozzles.

18. A method according to claim 17, further comprising the step of: detaching a fluid supply pipe from the body once a predetermined depth in the installation direction has been reached.

Images