Patent Description:
Sheet piles are used for the stabilization of a soil body. For large infrastructural projects, such as a deep underground parking garage, steel sheet piles are driven or vibrated into the subsoil. The steel sheet piles may have an inserted length of more than <NUM> meters. When the infrastructural project is finished, the steel sheet piles are usually removed to be reused. An example thereof and according to the preambles of claims <NUM> and <NUM> is disclosed in <CIT>.

For small infrastructural projects, such as a revetment ditch in a garden or park, single use plastic sheet piles are installed. However, the inserted length is very limited, in practice to about <NUM> meters, which can be reached by flushing the surrounding subsoil while the plastic sheet pile is pushed downwards into the subsoil. Alternatively, as disclosed in for example <CIT>, the plastic sheet piles are inserted in the subsoil while being fully enclosed in a protective metal housing.

It is an object of the present invention to provide a sheet piling installation for insertion of a sheet pile in a subsoil that can be used for plastic sheet piles with a length of more than <NUM> meters.

According to a first aspect, the invention provides a sheet piling installation for insertion of a sheet pile in a subsoil, wherein the sheet pile comprises a first sheet pile tube that defines a first sheet pile channel, and a second sheet pile tube that defines a second sheet pile channel, wherein the first sheet pile tube and the second sheet pile tube extend parallel to each other, and wherein the sheet piling installation comprises an elongated king post, and a drill assembly and a sheet pile guide assembly on the king post, wherein the drill assembly comprises an elongated first soil drill and a first drill drive assembly for rotation of the first soil drill, and an elongated second soil drill and a second drill drive assembly for rotation of the second soil drill, wherein the first soil drill and the second soil drill extend parallel to each other and pass through the respective first sheet pile channel and second sheet pile channel.

The sheet piling installation according to the invention comprises a first soil drill and a second soil drill that extend parallel to each other and that pass through the respective first sheet pile channel and second sheet pile channel, whereby the distal ends, in practice the drill heads, project downwardly beyond the bottom of the sheet pile to loosen the subsoil under the sheet pile tubes to facilitate the insertion of the sheet pile. This can be performed for any insertion length, and therefore for any length of the sheet pile. In this manner long plastic sheet piles can be inserted in the subsoil.

In an embodiment the first soil drill and the second soil drill comprise a base tube and a drill head at the end of the base tube, wherein the drill head comprises a head base on the base tube and multiple drill teeth that are moveable with respect to the head base between a retracted position in which the drill head fits through the first sheet pile channel or second sheet pile channel, and an extended position in which the outer diameter of the drill head is larger than the largest inner diameter of the first sheet pile channel or second sheet pile channel. According to this embodiment the soil drills can pass through the sheet pile tubes, whereafter the drill teeth are extended to loosen the subsoil amply under the sheet pile tubes.

In an embodiment thereof the drill teeth are hingable connected with the head base, wherein the drill teeth hinge between the retracted position and the extended position by engagement of surrounding soil and in dependency on a rotation direction of the drill head.

In an embodiment the first soil drill and the second soil drill comprise a flight that spirals around the base tube to remove the loosened subsoil under the sheet pile tubes.

In an embodiment the first soil drill and the second soil drill extend parallel to the king post.

In an embodiment the sheet pile guide assembly comprises one or more sheet pile guides that engage the sheet pile, and a positioning device that engages a sheet pile that is already inserted in the subsoil to facilitate the subsequent insert operations.

In an embodiment thereof the sheet pile comprises a first coupling edge and a second coupling edge along its length, wherein the positioning device is positioned with respect to the one or more sheet pile guides to bring the first coupling edge of the already inserted sheet pile in engagement with the second coupling edge of the sheet pile to be inserted in the subsoil.

In an embodiment the positioning device comprises one or more positioning cones that tightly wedge into the first sheet pile channel or second sheet pile channel.

In an embodiment the sheet pile is made of plastic.

According to a second aspect, the invention provides a method for insertion of a sheet pile in a subsoil by means of a sheet piling installation, wherein the sheet pile comprises a first sheet pile tube that defines a first sheet pile channel, and a second sheet pile tube that defines a second sheet pile channel, wherein the first sheet pile tube and the second sheet pile tube extend parallel to each other, and wherein the sheet piling installation comprises an elongated king post, and a drill assembly and a sheet pile guide assembly on the king post, wherein the drill assembly comprises an elongated first soil drill and a first drill drive assembly for rotation of the first soil drill, and an elongated second soil drill and a second drill drive assembly for rotation of the second soil drill, wherein the first soil drill and the second soil drill extend parallel to each other and pass through the respective first sheet pile channel and second sheet pile channel, wherein the method comprises insertion of the sheet pile while the first soil drill and the second soil drill are rotated, wherein during the insertion the first soil drill and the second soil drill project with their distal ends downwardly from a bottom edge of the sheet pile.

<CIT> discloses an apparatus for driving sheet piles, wherein the sheet piles comprise a web and a pair of oppositely sloping flange walls on both sides of the web. The apparatus comprises a screw auger and a tubular screw enclosure that is releasably hooked onto the sheet pile so as to leave exposed only the drill head of the screw auger.

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which:.

<FIG> shows a sheet piling installation <NUM> according to an embodiment of the invention for vertical insertion of sheet piles <NUM>, <NUM> in a subsoil <NUM>. The subsoil <NUM> comprises sand or clay that can be loosened.

The sheet piles <NUM>, <NUM> consist of a rigid plastic, in this example polyvinylchloride (PVC), and are intended for single use. The sheet piles <NUM>, <NUM> are prismatic and each comprise a hexagonal first sheet pile tube <NUM> with six straight tube wall sections <NUM> that define a first sheet pile channel <NUM>, and a hexagonal second sheet pile tube <NUM> with six straight tube wall sections <NUM> that define a second sheet pile channel <NUM>. The first sheet pile tube <NUM> and the second sheet pile tube <NUM> are connected to each other by means of a straight intermediate wall section <NUM>. The sheet piles <NUM>, <NUM> comprise a first end wall section <NUM> on the first sheet pile tube <NUM> that merges into a first coupling edge <NUM>, and a second end wall section <NUM> on the second sheet pile tube <NUM> that merges into a second coupling edge <NUM>. The first coupling edge <NUM> and the second coupling edge <NUM> mate with each other to interlock the sheet piles <NUM>, <NUM> along their length. The first end wall section <NUM>, the intermediate wall section <NUM> and the second end wall section <NUM> extend in a common straight plane. The sheet piles <NUM>, <NUM> comprise a top edge <NUM> as shown in <FIG>, and a bottom edge <NUM> as shown in <FIG>.

The sheet piling installation <NUM> comprises an hydraulically driven crawler crane <NUM> that is displaceable over the subsoil <NUM>. The crawler crane <NUM> comprises a crawler base <NUM>, a crane body <NUM> that is rotatable with respect to the crawler base <NUM> around a vertical axis, a boom <NUM> that is hingeable connected with the crane body <NUM> to hinge around a horizontal axis with respect to the crane body <NUM> by means of hydraulic cylinders, and an arm <NUM> that is hingeable connected with the boom <NUM> to hinge around a horizontal axis with respect to the boom <NUM> by means of hydraulic cylinders.

The sheet piling installation <NUM> comprises an elongate king post <NUM> with a centreline A that is kept vertically upright during insertion of the sheet piles <NUM>, <NUM>. The sheet piling installation <NUM> comprises a first bracket <NUM> that is hingeable connected to the distal end of the arm <NUM> to hinge around a horizontal axis with respect to the boom <NUM> by means of an hydraulic cylinder <NUM>, and a second bracket <NUM> that carries the king post <NUM> and that is hingable connected with the first bracket <NUM> to hinge around a hinge axis that extends parallel to the king post <NUM> by means of hydraulic cylinders. The hinging connections enable the sheet piling installation <NUM> to bring the vertical king post <NUM> at any location on the subsoil <NUM> around the crawler base <NUM>, and in any orientation around its centreline A within reach of the hinging connections. The hinging connections also enable the sheet piling installation <NUM> to turn up the king post <NUM> into its vertical position and to turn down the king post <NUM> to an oblique or horizontal position.

The sheet piling installation <NUM> comprises a hydraulically driven linear drive <NUM> between the king post <NUM> and the first bracket <NUM> that enables the sheet piling installation <NUM> to hoist and lower the king post <NUM> with respect to the first bracket <NUM> in direction B over a limited linear stroke.

The sheet piling installation <NUM> comprises a drill assembly <NUM> along the king post <NUM>. The drill assembly <NUM> comprises a carriage <NUM> that is guided along the king post <NUM> and a schematically indicated hydraulically driven drive belt <NUM> between the king post <NUM> and the carriage <NUM> for driving the carriage up and down in direction C along the king post <NUM>. The drill assembly <NUM> comprises a frame <NUM> on the carriage <NUM> that carries a first drill drive assembly <NUM> and a second drill drive assembly <NUM>. The first drill drive assembly <NUM> comprises a first hydraulic drill drive <NUM> that supports and rotates a hollow first drill drive shaft <NUM>. The first drill shaft <NUM> merges into a first drill drive coupling <NUM>. The second drill drive assembly <NUM> comprises a second hydraulic drill drive <NUM> that supports and rotates hollow second drill drive shaft <NUM>. The second drive shaft <NUM> merges into a second drill drive coupling <NUM>. The first drill drive coupling <NUM> and the second drill drive coupling <NUM> are positioned spaced apart from each other and extend at the same vertical height with respect to the carriage <NUM>.

The drill assembly <NUM> comprises an elongated first soil drill <NUM> with a first centreline S1 that is coupled with the first drill coupling <NUM>, and an elongated second soil drill <NUM> with a second centreline S2 that is coupled with the second drill coupling <NUM>. The first soil drill <NUM> and the second soil drill <NUM> extend with their centrelines S1, S2 parallel to each other and parallel to the centreline A of the king post <NUM>.

The soil drills <NUM>, <NUM> have the same length and both comprise one or more drill intermediate sections <NUM> and a drill end section <NUM> that are coupled in series. The drill intermediate sections <NUM> are selectively applied to adjust the length of the soil drills <NUM>, <NUM> to the length of the sheet piles <NUM>, <NUM>. The drill intermediate sections <NUM> comprise a hollow base tube <NUM>, one or more flights <NUM> spiralling around the base tube <NUM>, and end couplings <NUM> that mate with each other and with the drill drive couplings <NUM>, <NUM>.

The drill end sections <NUM> comprise a hollow base tube <NUM>, one or more flights <NUM> spiralling around the base tube <NUM>, and an end coupling <NUM> that mates with the end coupling <NUM> of the intermediate section <NUM> and with the drill drive coupling <NUM>, <NUM>. The drill end sections <NUM> comprise a drill head <NUM> at the end of the base tube <NUM>. The drill head <NUM> comprises a head base <NUM> on the base tube <NUM> and multiple drill teeth <NUM>, in this example three drill teeth <NUM> that are hingeable connected with the head base <NUM>. The drill teeth <NUM> hinge over a limited rotational stroke between a retracted position as shown in <FIG>, and an extended position as shown in <FIG>. The drill teeth <NUM> are evenly distributed around the circumference of the head base <NUM>. In the retracted position the distal ends of the drill teeth <NUM> are in the direction as from the head base <NUM> to the distal end all directed in the same tangential direction. In the retracted position the drill head <NUM> fits inside and can pass through the channels <NUM>, <NUM> of the sheet piles <NUM>, <NUM>. In the extended position the outer diameter of the drill head <NUM> along the distal ends of the drill teeth <NUM> is larger than the circumscribed circle of the tubes <NUM>, <NUM> of the sheet piles <NUM>, <NUM>. The drill teeth are automatically extended by engagement of the surrounding soil when the drill head <NUM> is rotated in the drilling direction of the soil drill <NUM>, <NUM>, and are automatically retracted by engagement of the surrounding soil when the drill head <NUM> is rotated in the opposite direction. The drill heads <NUM> of the first soil drill <NUM> and the second soil drill <NUM> extend at the same vertical height.

The drill assembly <NUM> comprises conduits <NUM> that are connected with the first soil drill <NUM> and the second soil drill <NUM> via the first drill drive assembly <NUM> and the second drill drive assembly <NUM>. The conduits <NUM> are connected with a flush water source for inserting flush water into the soil drills <NUM>, <NUM> that escapes via the drill heads <NUM> when needed for a particular subsoil <NUM>.

The sheet piling installation <NUM> comprises a sheet pile guide assembly <NUM> at the bottom side of the king post <NUM>. The sheet pile guide assembly <NUM> comprises a frame <NUM> against the king post <NUM>, and on the frame <NUM> a first sheet pile guide <NUM> for slidably engaging the first sheet pile tube <NUM> and a second sheet pile guide <NUM> for slidably engaging the second sheet pile tube <NUM> of the sheet piles <NUM>, <NUM>. The pile guide assembly <NUM> comprises a positioning device <NUM> on the frame <NUM> that comprises a first positioning cone <NUM> that tightly wedges in the first sheet pile channel <NUM>, and a second positioning cone <NUM> that tightly wedges in the second sheet pile channel <NUM>.

The sheet piling installation <NUM> comprises a drill scraper device <NUM> for releasing soil from the first soil drill <NUM> and the second soil drill <NUM> when retracted from the subsoil <NUM>. The scraper device <NUM> comprises a bracket <NUM> that is in this embodiment hingeable mounted to the frame <NUM> of the sheet pile assembly <NUM>. The drill scraper device <NUM> comprises a first scrape wheel <NUM> for the first soil drill <NUM> and a second scrape wheel <NUM> for the second soil drill <NUM>. The scraper wheels <NUM>, <NUM> comprise circumferential fingers <NUM> that loosely enclose the flights <NUM>, <NUM> of the first soil drill <NUM> and the second soil drill <NUM> when the bracket <NUM> is hinged upwards by means of an hydraulic cylinder <NUM>.

The sheet piling installation <NUM> comprises a not shown pushing device that is guided along the king post <NUM> and that engages the sheet pile <NUM>, <NUM> to push it in direction D downwards into the subsoil <NUM>.

The sheet piles <NUM>, <NUM> are inserted one after the other along an installation path F. For the first insert operation for the first sheet pile <NUM>, the drill assembly <NUM> is brought upwards along the king post <NUM> and the first first sheet pile <NUM> is hoisted or brought into the sheet piling installation <NUM>. The first soil drill <NUM> is thereby fed through the first sheet pile channel <NUM> and the second soil drill is fed through the second sheet pile channel <NUM>, wherein the drill teeth <NUM> are in their retracted position with respect to the head base <NUM>. The drill assembly <NUM> is positioned such that with respect to the first sheet pile <NUM> the drill heads <NUM> project downwardly from the bottom edge <NUM> of the first sheet pile <NUM>. The first sheet pile tube <NUM> and the second sheet pile tube <NUM> are engaged and vertically guided by the first sheet pile guide <NUM> and the second sheet pile guide <NUM>.

After the first sheet pile <NUM> is brought into the sheet piling installation <NUM>, the king post <NUM> is positioned to bring the bottom side of the first sheet pile <NUM> onto the installation path F. The first hydraulic drive assembly <NUM> and the second hydraulic drive assembly <NUM> rotate the first drill <NUM> and the second drill <NUM> in their drilling rotation direction E, whereby the drill teeth <NUM> hinge in direction G into their expanded position under the bottom of the first sheet pile <NUM> to simultaneously loosen the soil below the first sheet pile tube <NUM> and the second sheet pile tube <NUM>. The pushing device pushes the first sheet pile <NUM> downwards in direction D into the subsoil <NUM> while the drill assembly <NUM> is simultaneously moved downwards in direction C to keep the drill heads <NUM> in their leading position with respect to the bottom of the first sheet pile <NUM>. When the first sheet pile <NUM> has reached its final depth in the subsoil <NUM>, the drill assembly <NUM> changes the rotation direction of the soil drills to retract the drill teeth <NUM>, whereafter the soil drills are simultaneously hoisted out of the first sheet pile channel <NUM> and the second sheet pile channel <NUM>.

Subsequently the second sheet pile <NUM> is brought into the sheet piling installation <NUM> and inserted in the same manner. During this second insert operation, the first positioning cone <NUM> and the second positioning cone <NUM> are wedged in the first sheet pile channel <NUM> and the second sheet pile channel <NUM> of the first sheet pile <NUM> to ensure that the first coupling edge <NUM> and the second coupling edge <NUM> engage each other.

Claim 1:
Sheet piling installation (<NUM>) for insertion of a sheet pile (<NUM>) in a subsoil (<NUM>), wherein the sheet piling installation comprises a sheet pile, an elongated king post (<NUM>), and a drill assembly (<NUM>) and a sheet pile guide assembly (<NUM>) on the king post, wherein the drill assembly comprises an elongated first soil drill (<NUM>) and a first drill drive assembly (<NUM>) for rotation of the first soil drill, characterized in that the sheet pile comprises a first sheet pile tube (<NUM>) that defines a first sheet pile channel (<NUM>), and a second sheet pile tube (<NUM>) that defines a second sheet pile channel (<NUM>), wherein the first sheet pile tube and the second sheet pile tube extend parallel to each other, and wherein the drill assembly (<NUM>) comprises an elongated second soil drill (<NUM>) and a second drill drive assembly (<NUM>) for rotation of the second soil drill, wherein the first soil drill (<NUM>) and the second soil drill (<NUM>) extend parallel to each other and pass through the respective first sheet pile channel (<NUM>) and second sheet pile channel (<NUM>).