WO2019162668A1

WO2019162668A1 - A pile guide

Info

Publication number: WO2019162668A1
Application number: PCT/GB2019/050470
Authority: WO
Inventors: Luiz DEMENICIS; Barry KNIGHTING; Paul Redhead
Original assignee: Houlder Limited
Priority date: 2018-02-20
Filing date: 2019-02-20
Publication date: 2019-08-29
Also published as: GB2571138A; GB201802727D0

Abstract

In overview, a pile template in accordance with the disclosure comprises a base frame for engaging a substrate and a main frame having guide means for guiding at least one pile as it is driven into the substrate. Adjustable support means are provided on the base frame which support the main frame. Constraining means are also provided on the base frame arranged to engage the main frame to prevent substantial lateral movement of the main frame relative to the base frame, to enable the orientation of the main frame relative to the base frame to change, and to enable the distance of the base frame from the main frame at the engagement with the constraining means to vary, according to the arrangement of the adjustable support means.

Description

A PILE GUIDE

FIELD

The present disclosure relates to an apparatus and method for driving a pile into a substrate and, in particular, although not exclusively, to and a pile template configured to guide piles as they are driven into an underwater substrate with an uneven surface while keeping the distance between each pile constant, and a method of using said pile template.

BACKGROUND

Pile templates for guiding piles as they are driven into the seabed are known. EP2686488 describes a pile template having a main frame which includes three pile guide members in the form of cylindrical sleeves for receiving piles as they are driven into the seabed. The main frame is supported on a base frame via a support arrangement in the form of a ball and socket joint. The base frame has a planar substrate engaging surface. The main frame is adjusted relative to a base frame via a set of hydraulic rams which act about the central supporting ball and socket joint on which the main frame pivots. The ball and socket joint enables the main frame to pivot whilst being horizontally and vertically restrained relative to the base frame. The hydraulic rams at each end of the base frame can thus be actuated to pivot the main frame relative to the base frame. In this way the base frame can be placed on a surface on the seabed which is inclined relative to the horizontal. The hydraulic rams are either extended or retracted so that the main frame pivots relative to the base frame in such a way that the main frame is adjusted to be horizontal with the pile guide members vertical. Piles may then be vertically driven into the seabed despite the seabed being inclined.

In a system described in EP2686488, the support arrangement via which the load of the main frame is borne prevents all translational movement of the of the main frame relative to the base frame but permits rotational movement of the main frame relative to the base frame about the supporting ball and socket joint. Rotation of the main frame relative to the base frame about a third axis of rotation, about which the three pile guide members are radially and circumferentially spaced and which is also perpendicular to the two permitted axes of rotation, is prevented by the hydraulic rams. The pile template described in EP2686488 has several drawbacks as shall be explained. The suppression of the vertical axis of movement of the main frame relative to the base frame necessitates that the control of hydraulic rams must be accurately synchronised. Any imbalance in the control of the hydraulic rams would induce stress in the system. As such, there is an increased risk of component failure resulting from any slight imbalance in the control of the hydraulic rams. Further, the control system which controls the hydraulic rams is dependent upon the location of the support arrangement relative to the base frame. Any change in design of the pile template which results in a change in the location of the support arrangement and/or any of the hydraulic rams would require a complete reconfiguration of the control system.

In addition to the drawbacks associated with control of the hydraulic rams, there is a further drawback with respect to limitations imposed by the design of the pile template on the shape of the base frame. The vertical load of the main frame is borne by the base frame via the ball and socket joint. As a result of this, the base frame described in EP2686488 has a planar substrate engaging surface which is configured to contact the seabed at the location of the support arrangement such that the vertical load of the main frame can be transmitted directly to the seabed via the ball and socket joint and the base frame. This planar design of the base frame means that the pile template has reduced stability on seabed surfaces which are not planar, such as a surface with seabed sand waves. This is because parts of the seabed surface supporting the planar substrate engaging surface of the base frame may be at different heights resulting in parts of the planar substrate engaging surface not being in contact with the seabed surface. This could leave the base frame unbalanced resulting in the instability of the whole pile template, hence compromising the ability of a pile to be driven into the surface with the required accuracy.

SUMMARY

Advantageously, unlike in the known pile template described in EP2686488, constraining means are provided which enable the distance of the base frame from the main frame at the engagement with the constraining means to vary. In other words, a translational degree of freedom is permitted as the distance of the base frame from the main frame is permitted to change. In effect, the main frame is allowed to ride up and down relative to the base frame. The constraining means also permit the attitude of the main frame relative to the base frame to be adjusted. As a result, the main frame is isostatically supported on the base frame and the risk of stress in the system is greatly reduced when compared with aforementioned pile templates of the type disclosed in EP2686488 where no translational degrees of freedom are permitted, in particular, no vertical movement of the main frame relative to the base frame is possible. Further, control of the adjustable support means need not be as synchronised as with known pile templates of the aforementioned type as the additional translational degree of freedom provides a greater degree of tolerance in the control of the movement of the main frame.

In some aspects of the disclosure, a pile template suitable for supporting a pile as it is driven into a substrate is provided. The pile template includes a base frame for engaging the substrate and a main frame comprising guide means for guiding at least one pile as it is driven into the substrate. The pile template also includes adjustable support means on the base frame supporting the main frame. The pile template further includes a constraining means on the base frame arranged to engage the main frame to prevent substantial lateral movement of the main frame relative to the base frame and to enable the orientation of the main frame and its pile guide means relative to the base frame to change, and the distance of the base frame from the main frame at the engagement with the constraining means to vary, according to the arrangement of the adjustable support means.

In some embodiments, the constraining means may include a post on the base frame and the main frame may have an aperture within which the post is disposed. The post may be located at the centre of the base frame. The aperture may be located at the centre of the main frame. The constraining means further may include a sleeve slidably mounted to the post and the sleeve may be disposed in the aperture of the main frame. The sleeve enables the main frame to slide up and down the post. In this way, translational movement of the main frame away from or towards the base frame is permitted. In other words, the distance of the base frame from the main frame at the point at which the main frame engages the constraining means can vary.

The sleeve may comprise an outwardly curved surface and the main frame, for example a central portion of the main frame, may comprise a corresponding inwardly curved surface engaged with the outwardly curved surface of the sleeve. In other words, the curved surfaces are shaped to match one another. The curved surfaces are able to slide relative to each other and, in this way, the orientation of the main frame relative to the base frame can be changed. The inwardly curved surface may be located at the aperture of the main frame within which the post is disposed.

The post may comprise an abutment configured to limit the range of movement of the sleeve along the post. In this way, although translational movement of the main frame relative to the base frame is permitted, the range of such movement is limited by the abutment. In some embodiments, the post may comprise a further abutment such that range of movement of the sleeve along the post is limited in both directions. The abutments may be respectively located along the post at either end of the sleeve with the sleeve movable along the post between the abutments.

In some embodiments, the pile template may also comprise only a single constraining means.

In some embodiments, the pile template may further comprise a restraining member on the base frame configured to prevent substantial rotation of the main frame about the post. The restraining member may be configured to engage with the main frame, thereby preventing its rotation about the post.

In some embodiments, the main frame may include a plurality of guide means. The plurality of pile guide means may be arranged around the constraining means. The plurality of pile guide means may be radially spaced equally from the support

arrangement. The plurality of pile guide means may be circumferentially spaced equally around the support arrangement.

The guide means may each be disposed at a periphery of the main frame. The adjustable support means may include a respective support member coupled to the main frame at the location of each of the guide means. Each support member may have an adjustable strut, such as a hydraulic actuator. The orientation of the main frame relative to the base frame can be varied by extending and retracting the adjustable struts of the support means.

In some embodiments, the or each guide means may include a pile engaging sleeve having first and second pile engaging portions configured to move between an open position, which may be for receiving a pile in the guide means and/or for allowing a pile to be driven further into the substrate, and a closed position for guiding a pile once into the guide means. In this way, a pile can be easily inserted into the pile engaging sleeve while in the open position and, when the pile is to be driven into a substrate, the pile engaging sleeve may be moved into the closed position so as to guide the pile. Once the pile has been driven into the substrate to the point where the top of the pile is close to the top of the guide means, it may not be possible for a hammer with a larger diameter than the guide means (when in the closed position) to continue driving the pile into the substrate.

In this situation, the guide means can be moved to the open position so as to allow such a hammer to continue driving the pile into the substrate from a position which is closer to the substrate than would otherwise be possible (e.g. when using the pile template described in EP2686488) without having to remove the template from its guiding position.

The or each guide means may comprise an actuator configured to move the first and second pile engaging portions between the open and the closed positions. The actuator may be an adjustable strut, such as a hydraulic actuator. A locking mechanism may be provided to lock the pile engaging sleeve of the or each guide means in the closed position.

In some embodiments, the base frame may comprise a raised portion on which the constraining means are disposed. As the constraining means do not bear the vertical load of the main frame, it can be placed on a raised portion of the base frame meaning that a variety of configurations of base frame shapes are possible.

In some embodiments, the base frame is configured such that, when placed on a planar substrate, the base frame is raised from the substrate at the location of the constraining means.

In some embodiments, the base frame may further comprise radially spaced legs extending from the raised portion, wherein each arm comprises a surface for engaging the substrate. The base frame may comprise three such radially spaced legs.

Advantageously, a base frame with such a configuration may be securely disposed on non-planar substrates, such as surface with seabed sand waves. In the embodiment where three radially spaced legs are provided, the base frame is able to stably engage surfaces with a wide variety of profiles as improved stability against downward forces and horizontal forces and movements about horizontal axes is provided.

In some aspects of the disclosure, a method of guiding at least one pile as it is driven into a substrate is provided. The method comprises providing a pile template according to the above aspect, positioning the base frame on the substrate, changing the orientation of the main frame relative to the base frame by controlling the adjustable support means and/or changing the distance of the base frame from the main frame at the engagement with the constraining means. In this way, a pile can be accurately driven into a substrate using a pile template even when the surface of the substrate is inclined relative to the horizontal or is uneven.

The method may further comprise engaging a pile with the guide means and driving the pile into the substrate.

Where the guide means includes a pile engaging sleeve having first and second pile engaging portions configured to move between an open position and a closed position, the method may further comprise, once a pile has been driven into the substrate to the level of the guide means, moving the guide means into the open position, for example by moving the first and second pile engaging portions to the open position, and continuing to drive the pile into the substrate past the level of the guide means.

The method may further comprise the step of removing the pile template from the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are now described by way of example for the purpose of explanation and illustration, with reference to the accompanying drawings in which:

FIG.1 depicts a pile template;

FIG.2a depicts a profile view of the pile template on a flat substrate;

FIG.2b depicts a profile view of the pile template on an inclined substrate;

FIG.3a depicts a plan view of the pile template with pile engaging sleeves in a closed position; FIG.3b depicts a plan view of the pile template with pile engaging sleeves in a open position;

FIG.4 depicts a cross section of a constraining means;

FIG.5 depicts a restraining member; and

FIG.6 illustrates a method for driving a pile into a substrate.

DETAILED DESCRIPTION OF THE DRAWINGS

Some specific embodiments are now described by way of illustration with reference to the accompanying drawings in which like reference numerals refer to like features.

With reference to Figure 1 , a pile template 100 comprises a base frame 102 and a main frame 104 mounted on the base frame via an adjustable support 106 in the form of three hydraulic actuators 106. The depicted base frame 102 has a raised central portion 110 and three radially spaced legs 112 extending from the raised portion. Each leg 112 comprises a surface for engaging the substrate. The construction of the depicted base frame 102 is that of a lattice structure constructed from interlocking struts.

The main frame 104 is also a lattice structure constructed from interlocking struts. The depicted main frame 104 is triangular in shape. The main frame 104 could equally be square in shape, or any other suitable shape, depending on the number of guide means 116 provided. The main frame 104 has a central hub 114 about which three guide means 116 are radially and circumferentially spaced. A greater number of guide means than the depicted number could be provided, for example, four guide means could be provided on a square main frame. In the depicted embodiment of pile template 100, each guide means 116 is located at the periphery of the main frame 104, at a corner. The guide means 116 each include a pile engaging sleeves comprising a first pile engaging portion 118 and a second pile engaging portion 120 which are connected to each other and the main frame 104 via a hinge. Actuators 122 are coupled to each first pile engaging portion 118 and each second pile engaging portion 120 which are configured to move the first and second pile engaging portions between open and closed positions. A locking mechanism 124 is also provided to lock each pile engaging sleeve of each guide means 116 in the closed position.

The main frame 104 is supported on the base frame 102 by three hydraulic actuators 106 mounted to the base frame 102 and coupled to the main frame 104. A single hydraulic actuator 106 is located on the base frame 102 at the location of each corner of the main frame 104. The vertical load of the main frame 104 is borne by the base frame 102 via the three hydraulic actuators 106.

A constraining means (not visible in Figure 1) is provided on the raised portion of the base frame 102. The constraining means is arranged to engage the main frame to prevent substantial lateral movement of the main frame relative to the base frame, to enable the orientation of the main frame relative to the base frame to change, and to enable the distance of the base frame from the main frame at the engagement with the constraining means to vary, according to the arrangement of the hydraulic actuators 106. An example construction of the constraining means is described in greater detail in the below discussion of Figure 4.

A restraining member (not visible in Figure 1) is provided on the base frame 102 configured to prevent substantial rotation of the main frame 104 about the longitudinal axis of the central hub 114 of the main frame 104. The restraining member is configured to engage with the main frame, thereby preventing rotation of the main frame 104 about the longitudinal axis of central hub 114. An example construction of the restraining member is described in greater detail in the below discussion of Figure 5.

Figure 2a depicts a profile view of the pile template 100 on a flat surface and Figure 2b depicts a profile view of the pile template 100 on an inclined surface. The raised central portion 110 and three radially spaced legs 112 of the base frame 102 are clearly visible. The constraining means 400 and the restraining member 500 are also clearly visible. The constraining means 400 is mounted to the base frame 102 and engages main frame 104 in such a way as to restrict movement of the main frame 104 relative to the base frame 102 in the aforementioned manner. The restraining member 500 is mounted to the base frame 102 and engages either side of a strut of the main frame 104 so as to prevent rotation of the main frame 104 about the longitudinal axis of the hub 114.

Figure 3a depicts a plan view of the pile template 100 with the first pile engaging portion 118 and a second pile engaging portion 120 in the closed position. Figure 3b depicts a plan view of the pile template 100 with the first pile engaging portion 118 and a second pile engaging portion 120 in the open position. It will be appreciated that a pile can be easily inserted or removed from any particular guide means 116 when the first pile engaging portion 118 and a second pile engaging portion 120 in the open position. It will also be appreciated that a pile can be driven beyond the upper surface of the guide means 116 after it has been moved into the open position. In this way, the pile template need not be removed before a pile can be driven beyond the upper surface of the guide means 116, as would be the case with the pile template described in EP2686488.

Figure 4 depicts a cross section of the constraining means 400. The constraining means 400 comprises a post 402 which is mounted to the base frame 102. A sleeve 406 is slidably engaged with the post. The sleeve 406 has an outwardly curved surface.

Coupled to the sleeve is a cup 404 which is mounted to the main frame 104. In an alternative embodiment, the cup may be an integrally formed part of the main frame 104. The cup 404 defines an aperture within which the post 402 and sleeve 406 are located. The cup 404 has an inner surface 408 which is inwardly curved such that it corresponds to and engages with the outwardly curved surface of the sleeve 406. The corresponding curved surfaces are able to slide relative to each other and, in this way, the orientation of the main frame 104 relative to the base frame102 can be changed while keeping the main frame 104 restrained radially in the horizontal plane.

As the sleeve 406 is able to slide along the post 402, the distance between the cup 404 of the main frame 104 and the base frame 102 can vary. The extent of movement of the sleeve along the post 402 is restricted by a lower abutment 410 on the post and an upper abutment 412.

It will be appreciated that the constraining means 400 depicted in Figure 4 prevents substantial lateral movement of the main frame 104 relative to the base frame 102. The constraining means 400 also enables the orientation of the main frame 104 relative to the base frame 102 to change according to the arrangement of the adjustable support by virtue of the engagement between the inwardly curved inner surface 408 of the cup 404 and the corresponding outwardly curved surface of the sleeve 406. Further, the distance of the base frame 102 from the main frame 104 at the engagement with the constraining means (i.e. the cup 404) can vary according to the arrangement of the adjustable support.

Figure 5 depicts the restraining member 500. The restraining member has two arms 502 which sit either side of a strut of the main frame 104 and which define a channel between them within which vertical movement of the strut of the main frame 104 is permitted but which prevents any horizontal movement of the strut. As the restraining member 500 is mounted to the base frame 102, it acts to restrict any rotation of the main frame104 about the post 402 of the constraining means 400 and about the longitudinal axis of the central hub 114 of the main frame104. Further, in conjunction with the constraining means 400, the restraining member 500 defines a preferred axis of rotation for the main frame104 along the line between the constraining means 400 and the restraining member 500.

In an alternative embodiment, the restraining member may be in the form of a pair of hydraulic actuators mounted to the base frame 102 and coupled to the main frame 104. This pair of actuators may be located at the location of one of the corners of the main frame 104 in place of the single hydraulic actuator 106 which would be present in the depicted embodiment. This pair of hydraulic actuators may be mutually inclined towards each other so as to restrict any rotation of the main frame 104 about the post 402 of the constraining means 400, and about the longitudinal axis of the central hub 114 of the main frame 104. A preferred axis of rotation for the main frame104 would be provided along the line between the constraining means 400 and the mutually inclined hydraulic actuators.

Figure 6 illustrates a method by which a pile can be guided as it is driven into a substrate using the pile template 100. At step 601 , the base frame 102 of the pile template 100 is positioned on a substrate, such as the seabed. At step 602, the orientation of the main frame 104 relative to the base frame 102 can be changed by controlling the hydraulic actuators 106 so as to account for any incline in the substrate. In doing so, the constraining means 400 enables the distance of the base frame 104 from the main frame at the engagement with the constraining means to vary, thereby reducing the likelihood of any stress in the system.

The method may further comprise engaging a pile (not shown in the drawings) with the guide means 116, at step 603, for example by inserting the pile through the guide means 116. The guide means 116 could either be in the open or the closed position at this point.

The method may further comprise driving the pile into the substrate, with the guide means 116 in the closed position, until the top of the pile and/or a driving apparatus (not shown in the drawings) are close to, or at the level of, the guide means 116, at step 604.

The method may further comprise moving the first and second pile engaging portions of the guide means 116 to the open position, at step 605.

The method may further comprise continuing to drive the pile into the substrate past the level of the guide means 116, at step 606. Finally, the method may further comprise removing the pile template 100 from the substrate.

Claims

1. A pile template for supporting at least one piles as it is driven into a substrate, the pile template comprising:

a base frame for engaging the substrate;

a main frame comprising guide means for guiding at least one pile as it is driven into the substrate;

adjustable support means on the base frame supporting the main frame; and constraining means on the base frame arranged:

to engage the main frame to prevent substantial lateral movement of the main frame relative to the base frame;

to enable the orientation of the main frame relative to the base frame to change; and

to enable the distance of the base frame from the main frame at the engagement with the constraining means to vary, according to the arrangement of the adjustable support means.

2. The pile template of claim 1 , wherein the constraining means comprises a post on the base frame, wherein the main frame comprises an aperture within which the post is disposed.

3. The pile template of claim 2, wherein the constraining means further comprises a sleeve slidably mounted to the post, wherein the sleeve is disposed in the aperture.

4. The pile template of claim 3, wherein the sleeve comprises an outwardly curved surface, wherein the main frame comprises a corresponding inwardly curved surface engaged with the outwardly curved surface of the sleeve.

5. The pile template of claim 3 or claim 4, wherein the post comprises an abutment configured to limit the range of movement of the sleeve along the post.

6. The pile template of any preceding claim, wherein the pile template comprises a single constraining means.

7. The pile template of any of claims 2 to 6, wherein the pile template further comprises a restraining member on the base frame configured to prevent substantial rotation of the main frame about the post.

8. The pile template of claim 7, wherein the restraining member is configured to engage with the main frame, thereby preventing rotation of the main frame about the post.

9. The pile template of any preceding claim, wherein the main frame comprises a plurality of guide means, wherein the adjustable support means comprises a respective support member coupled to the main frame at the location of each of the guide means.

10. The pile template of claim 9, wherein each support member comprises an adjustable strut.

11. The pile template of any preceding claim, wherein the or each guide means comprise a pile engaging sleeve having first and second pile engaging portions configured to move between an open position and a closed position.

12. The pile template of claim 11 , wherein the or each guide means comprises an actuator configured to move the first and second pile engaging portions between the open and the closed positions.

13. The pile template of claim 11 or claim 12, further comprising a locking mechanism to lock the pile engaging sleeve of the or each guide means in the closed position.

14. The pile template of any preceding claim, wherein the base frame comprises a raised portion on which the constraining means is disposed.

15. The pile template of claim 14, wherein the base frame further comprises radially spaced legs extending from the raised portion, wherein each leg comprises a surface for engaging the substrate.

16. A method of guiding at least one pile as it is driven into a substrate, the method comprising:

providing a pile template according to any preceding claim;

positioning the base frame on the substrate;

changing the orientation of the main frame relative to the base frame by controlling the adjustable support means and/or changing the distance of the base frame from the main frame at the engagement with the constraining means.