Patent Description:
A common method for constructing a seabed wall structure is to use a temporary template structure or falsework to position and align the piles prior to and during installation. However, existing systems for the installation of subsea walls typically require the use of extensive falsework systems or use falsework that extends below the waterline to provide support for the piles during installation. Often divers are used in conjunction with falsework to confirm alignment and/or successful pile to pile interlock.

An alternate method of installation is to extend the length of the pile to the waterline, which simplifies construction, and cut off the ends of the piles once the installation is completed. Related construction methods can be found in <CIT>, which discloses a dock building apparatus and method of construction, <CIT>, which discloses a method and equipment for making an impermeable diaphragm of secant piles, <CIT>, and <CIT>. A further example of a construction method, where a foundation structure is driven into the sea bed together with the pile, is shown in <CIT>.

A number of limitations stem from the common methods for constructing a seabed wall structure. First, the construction rate is typically limited by the movement and setup time of the falsework; second, the cost of the falsework can be significant, depending on the pile geometry, water depth, and accuracy required; third, in many cases, the installation must be carried out during the day time, or have a limited production rate at night; and fourth, the method that cuts off the ends of piles requires additional operations and material, which affects productivity and cost.

Therefore, it is the object of the present invention to solve the above described problems and provide an improved construction apparatus and method for construction of subsea structures that is able to locate piles accurately underwater with very high precision from a land based system without extensive falsework.

According to the invention, a method of driving a pile into a seabed floor adjacent to an existing foundation structure is provided. The method comprises lowering a lead longitudinally oriented in a first direction toward the subsea floor; engaging a lead indexing foot of the lead with the existing foundation structure; and advancing the pile, along the lead, in the first direction into the subsea floor.

In this configuration, the lead indexing foot allows the lead to align with the existing foundation structure. Because the lead is indexed with the existing foundation structure, it is possible to install the pile during times with low viability, for example, turbulent water or night.

In aspects, the method may further comprise inserting an interlock of the pile into an interlock of the existing foundation structure.

In this configuration, the interlock ensures that the pile is properly aligned while the pile is being driven into the seabed floor.

In aspects, the method may further comprise determining whether the interlock of the pile has engaged the interlock of the adjacent existing foundation structure.

Determining whether the respective interlocks are properly engaged prior to driving the pile into the seabed floor prevents damage to the pile, damage to the existing foundation structure, and improper placement of the pile.

In aspects, the method may further comprise attaching the lead to a template that is adapted to move in a second direction that is perpendicular to the first direction.

Having a detachable template allows for the template to be moved concurrently with a pile being loaded into the lead.

In aspects, the method may further comprise adjusting the location of the lead by moving the template on at least one rail.

The benefit of providing a template that is slidably connected to a rail allows for an efficient installation of multiple piles in different locations.

In aspects, the method may further comprise loading the pile onto the lead prior to the step of lowering the lead in the first direction.

This method may be preferable, for example, while performing an installation in turbulent water so that the lead does not remain submerged for longer than required.

In aspects, the method may further comprise loading the pile onto the lead after the step of lowering the lead.

This method may be preferable, for example, while performing an installation in placid water. This method reduces the instillation time because the entire lead can be adjusted contemporaneously with the template rather than be disconnected therefrom.

It is intended that combinations of the above-described elements and those within the specification may be made, except where otherwise contradictory.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, and serve to explain the principles thereof.

Reference will now be made in detail to exemplary embodiments of the disclosure, examples of which are illustrated in the accompanying drawings.

<FIG> shows an apparatus for installing a seabed wall <NUM>. The apparatus may include a lead <NUM>, a template <NUM>, rails <NUM>, and a pile insertion device <NUM>.

The lead <NUM> comprises a long structural column that extends along an axis Y1 from a top end 10a to a bottom end 10b; the top end 10a is higher in elevation than the bottom end 10b.

The lead <NUM> is a self-supporting system that uses integrated winches or crane winches to control the lead lift and elevation, the tool (e.g., pile driving hammer) lift and elevation, and the pile lift and elevation. The lead <NUM> is also equipped with an integrated slide <NUM> (shown in <FIG>) which has a built-in interlock with the template <NUM> and a range of motion (vertical movement) suitable for a specific project. The hydraulic power that actuates the lead <NUM> integrated systems (winches, guiding gates and driving/drilling tools) is provided by the supporting crane hydraulics or additional valve control system with a separate power pack unit or a combination of both (not shown).

As shown in <FIG>, the lead <NUM> may have one or several gates <NUM> that are configured to position and align a foundation element, for example, a pile <NUM>, relative to the lead <NUM>. The gate <NUM> may include at least one gate arm 14a, that may be configured to swing between open and closed positions. The opening and closing of the gate arm 14a may be controlled by any suitable means, for example, hydraulics.

The lead <NUM> further comprises a lead indexing foot <NUM> that extends along an axis Y2 that is laterally offset from the lead axis Y1. The lead indexing foot <NUM> is attached to the bottom end 10b of the lead. The lead indexing foot <NUM> may be joined to the bottom end 10b of the lead by, for example, welding or the lead indexing foot <NUM> may be fully integrated with the lead <NUM> as a unitary piece.

As shown in <FIG>, the lead indexing foot <NUM> may form a tip portion 16a that is configured to align with an opening of an existing foundation structure <NUM>, for example, a previously installed pile, group of piles, sheets, submerged supports laying on the seabed, etc. The lead indexing foot <NUM> further comprises a fitted portion 16b that is configured to at least partially contact an interior surface of the opening of the existing foundation structure <NUM>. The lead indexing foot <NUM> further comprises a base portion 16c that is configured to interface with a top end 60a of the existing foundation structure <NUM>.

The radial distance ra from the axis Y2 of the tip portion 16a may be smaller than a radial distance rb from the Y2 axis than the fitted portion 16b. A surface that extends between the tip portion 16a and the fitted portion 16b of the lead indexing foot <NUM> may be tapered.

The lead <NUM> may further comprise a second lead indexing foot <NUM> that is configured to align and interface with another portion of the existing foundation structure <NUM>, for example, an adjoining previously installed pile. The second lead indexing foot <NUM> may extend along a third axis Y3 that is laterally offset from both the lead axis Y1 and the first indexing foot axis Y2. This second lead foot can be used to provide additional alignment of the lead and pile.

As seen in <FIG>, the ground level template <NUM> consists of a structural frame that is installed on rails <NUM>, which aid in the alignment and movement of the template <NUM>. The template <NUM> and rails <NUM> may be made of any suitable material, for example, steel, iron, aluminium, etc..

The position of the template <NUM> can be fixed or can be moved to a predetermined location based on the required foundation spacing. The template <NUM> is configured to be removeably connected to the lead <NUM>.

The template <NUM> may have a pivotable connection <NUM> with the lead <NUM>. For example, the pivotable connection <NUM> of the template <NUM> may be configured to pivot the lead <NUM> about a first pivot axis so that an operator can account for any construction deviation in the piles and the lead may be adjusted to steer the pile position to maintain the construction within a specified tolerance. The pivotable connection <NUM> may be further configured to pivot the lead about a second or a third pivot axis. The pivotable connection <NUM> may be lockable such that the lead <NUM> can be locked into place after pivoting it about a first, second, and/or third pivot axis.

The pile insertion device <NUM> may be attached to the lead <NUM> by any suitable means, for example, fasteners. The pile insertion device <NUM> may be attached proximate to the top end 10a of the lead <NUM>. The pile insertion device <NUM> may be any appropriate means to insert a pile into a seabed floor F, for example, a pile driving vibrating or impact hammer.

In operation, the template <NUM> is installed on rails <NUM> or rollers that are leveled and aligned with a subsea pile grid along the wall to be constructed. After assembly of the lead <NUM> and appropriate placement of the template <NUM>, the lead <NUM> is held vertically with the lead indexing foot <NUM> touching the ground or connected to a supplied stand that limits movement during pile <NUM> lifting and loading.

As shown in <FIG>, the hydraulic gate <NUM> is opened and then the pile <NUM> is connected to the pile line and lifted vertically using a crane or integrated lifting winches. The hydraulic gate <NUM> is subsequently closed such that the pile <NUM> interlocks 50f, <NUM> are now aligned with the pile line. The interlocks 50f, <NUM> will be discussed in more detail with reference to <FIG>.

The lead <NUM> having the pile <NUM> therein is lifted, moved, and then lowered to be connected to the template <NUM>. The lead assembly may be lifted using a crane. The lead integrated slide engages the template <NUM> by locking thereto. The provided locks, which have <NUM> axis lockable rotation, are engaged to maintain proper alignment in the horizontal and vertical directions, as well as prevent unwanted movement.

The lead <NUM> is then lowered toward the seabed floor F. The lead <NUM> is maintained in a vertical position, which can be monitored with, for example, inclinometers, plumb system, or hand held level tools. As the lead <NUM> is lowered, the tip portion 16a of the lead <NUM> will initially be inserted into the opening of an existing foundation structure <NUM>, e.g., previously installed pile. The tapered surface between the tip portion 16a and fitted portion 16b pilots the lead indexing foot <NUM> until the existing foundation structure contacts the base portion 16c of the lead indexing foot <NUM>. Thus, the lead indexing foot <NUM> is inserted into and is supported by the existing foundation structure <NUM>. In this configuration, the lead <NUM> is substantially connected to the lead indexing foot <NUM>.

As can be seen in <FIG>, it is envisioned that the lead <NUM> may have a second lead indexing foot <NUM> that is configured to engage another portion of the existing foundation structure <NUM> in a similar manner as the previously discussed, first lead indexing foot <NUM>. The second lead indexing foot <NUM> may extend along an axis Y3 that is laterally offset from axes Y1 and Y2. The second lead indexing foot <NUM> may have a similar shape as the first lead indexing foot <NUM> and be disposed on the second end 10b of the lead <NUM>.

Turning to <FIG> and <FIG>, after at least one lead indexing foot <NUM> is fully inserted into the existing foundation structure <NUM>, the pile <NUM> that is loaded in the lead <NUM> is in proper alignment and can be lowered.

The pile <NUM> has interlocks <NUM>, 50f that is adapted to engage interlocks <NUM>, 60f of the existing foundation structure <NUM>. For example, at least a portion of pile <NUM> may have a male type interlock <NUM> that extends along a length of the pile <NUM>, parallel to axis Y1. The existing foundation structure <NUM>, which may be an existing pile, may have a female type interlock 60f that extends along a length of the existing foundation structure <NUM>, parallel to axis Y2. Therefore, when the pile <NUM> is being lowered toward the seabed floor F, the respective interlocks <NUM>, 60f engage each other. Any suitable interlocking means may be implemented, for example a T-shaped protrusion and a corresponding channel. Cameras and/or sensors may be used to ensure that the respective interlocks <NUM>, 60f are properly engaged.

After it is determined that the respective interlocks <NUM>, 60f are properly engaged, the gates <NUM> are opened allowing the pile <NUM> to be lowered to the seabed floor F. Once the pile contacts the seabed floor F, the pile insertion device <NUM> drives the pile <NUM> therein. The pile insertion device <NUM> may be an impact hammer, a vibratory hammer, or a means to drill the pile <NUM> into the seabed floor F. A feedback means may be used with the gates <NUM>, for example hydraulic flags configured to provide visual feedback on the gate position (open/close) even when water turbidity prevents visual confirmation or during a night time installation.

Once the pile <NUM> has been installed into the seabed floor F, the lead <NUM> is elevated vertically, away from the seabed floor F. The lead <NUM> is moved back into its initial position and thereafter disconnected from the template <NUM>. At this point, a new pile can be loaded into the lead <NUM>. This may be done concurrently with moving the template <NUM> to the next position. The template <NUM> may be advanced using a wire rope, winches, or hydraulically actuated cylinders.

The benefits of performing this method of operation using the lead <NUM> having at least one lead indexing foot <NUM> is that lowering the lead indexing foot <NUM> into the existing foundation structure <NUM>, e.g., previously installed piles, fine tunes the alignment of the lead <NUM> at seabed elevation and allows the lead <NUM> to index using the existing foundation structure <NUM>. Further, because the lead <NUM> is indexed with both the existing foundation structure <NUM> and the template <NUM>, it is possible to determine the position and alignment of the existing foundation structure <NUM> by surveying or instrumentation on the lead <NUM>. This enables installation of a seabed wall during times with low viability, for example, turbulent water or night.

An alternative method of installing a pile <NUM> into the seabed floor F is similar to the previous method, except that the lead <NUM> is connected to the template <NUM> without having a pile <NUM> loaded therein. The lead <NUM> is then lowered toward the seabed floor F. Similar to the previous exemplary method, the lead indexing foot <NUM> is inserted into and is supported by the existing foundation structure <NUM>. Also similar to the previous method, it is envisioned that the lead <NUM> may have a second lead indexing foot <NUM> that is configured to engage another portion of the existing foundation structure <NUM>.

After at least one lead indexing foot <NUM> is fully inserted into the existing foundation structure <NUM>, the pile <NUM> is loaded into or onto the lead <NUM> and secured with a movable gate <NUM>. The pile <NUM> is then lowered toward the seabed floor F.

Similar to the previous method, after the respective interlocks <NUM>, 60f of the pile <NUM> and existing foundation structure <NUM> are properly engaged, the gates <NUM> are opened allowing the pile <NUM> to be lowered to the seabed floor F and the pile insertion device <NUM> drives the pile <NUM> therein.

After the pile <NUM> has been installed into the seabed floor F, the lead <NUM> is elevated vertically, away from the seabed floor F and into its initial position. Thereafter, the lead <NUM> can be moved concurrently with the template <NUM> to the next position. The lead <NUM> and template <NUM> assembly may be advanced using a wire rope, winches, or hydraulically actuated cylinders.

The benefits of performing this method of operation using the lead <NUM> having at least one lead indexing foot <NUM> is that lowering the lead indexing foot <NUM> into the existing foundation structure <NUM> remains the same as the previous method in that the lead indexing foot <NUM> fine tunes the alignment of the lead <NUM> at seabed elevation and allows the lead <NUM> to index using the existing foundation structure <NUM>. However, if the installation is occurring in placid or calm water, refraining from disconnecting the lead <NUM> from the template <NUM> after every pile <NUM> is driven, and adjusting the lead <NUM> with the template <NUM>, expedites the installation process.

Throughout the description, including the claims, the term "comprising a" should be understood as being synonymous with "comprising at least one" unless otherwise stated.

Although the present invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure.

Claim 1:
A method of driving a pile (<NUM>) into a seabed floor (F) adjacent to an existing foundation structure (<NUM>), the method comprising:
lowering a lead (<NUM>) longitudinally oriented in a first direction toward the subsea floor (F);
engaging a lead indexing foot (<NUM>) of the lead (<NUM>) with the existing foundation structure (<NUM>); and
advancing the pile (<NUM>), along the lead (<NUM>), in the first direction into the subsea floor (F).