Plastic sheet piling panel

Abstract

The object of the present invention is to provide a sheet pile resistant to UV radiation, which does not deform or degrade over time due to prolonged exposure to UV radiation, and which does not lose its preferable mechanical properties. The object of the present invention is also to provide a sheet pile that is not easily damaged when being inserted into the ground, despite being made entirely of plastic material. The object of the invention has been achieved by providing an elongated sheet piling panel having a top end and a bottom end for driving the panel into the substrate, and a first wall and a second wall arranged parallelly to each other, whereby the first wall and the second wall are connected by partitions extending between said walls inside the panel and oriented along the length of the panel, from the top end to the bottom end of the panel, thereby forming hollow chambers extending longitudinally. The air contained in the chambers of the sheet piling panel acts as a thermal insulator, what allows the temperature of the wall regions which are not exposed to solar radiation to be lowered enough to prevent deformation of the panel. At the bottom end of the panel the chambers are closed. Closing the chambers at the bottom end of the panel allows to prevent the substrate from entering into the chambers during insertion, and thus prevents damaging the chambers.

Description

Field of the invention

[0001] This invention concerns the field of sheet piling panels that can be connected with each other to form a wall system. More particularly, this invention relates to sheet piling panels that can be driven into the ground to form a tight wall that prevents water from entering or prevents soil displacement.Prior art

[0002] Sheet piles are structural elements, typically made of steel, concrete, or wood, used in construction to create retaining or sealing walls. Their main purpose is to protect against water infiltration, secure excavation sites, and stabilize soil. Sheet piles have a form of elongated, planar sheets and are driven vertically into the ground, thereby forming a tight wall, such as retaining wall or sea wall.

[0003] Sheet piles may be used for temporary or permanent protection of excavation sites, such as during the construction of foundations, tunnels, or underground structures. They prevent soil from shifting and collapsing into the excavation and block groundwater from entering. In situations where there is a risk of water entering a construction area (e.g., near rivers, water reservoirs, or in areas with high groundwater levels), sheet piles create a barrier that prevents flooding. Sheet piles also serve as retaining walls, stabilizing soil on slopes, embankments, or areas at risk of landslides. They prevent erosion and the movement of soil masses. In hydraulic engineering, sheet piles are commonly used to build quays, docks, and ports. They form solid walls that can serve as structural elements or as protection against water flow.

[0004] For connecting the sheet piling panels with each other, the sheet piling panels on their side edges are equipped with interlocking formations, enabling interlocking of the edges of the adjacent panels to provide a permanent connection of the panels in order to form a continuous, tight wall. There is no standard interlock design and thus the interlocking formations may be provided in various types, such as Larssen interlock, thumb and finger interlock, male-female interlock, or interlock using separate connector elements fitting into formations provided on the side edges of the sheet piles.

[0005] Sheet pilings are manufactured in various cross-sectional configurations, the most popular of which are for example Z-shaped, U-shaped, arch-shaped, box shaped or straight flat configurations.

[0006] Depending on the necessary properties of sheet piles, sheet piles may be made of various types of material, including concrete, steel, aluminum, treated timber, or plastic materials, such as PVC (polyvinyl chloride) or pultruded fiber-reinforced polymer material.

[0007] Steel sheet piles are commonly used due to their strength and flexibility, however they are susceptible to corrosion and are heavy. Aluminum sheet piles are more corrosion-resistant than steel, but are more expensive. The use of timber sheet piles is restricted due to environmental controls related to preservatives used to treat timber. Concrete sheet piles are primarily used where durability and high resistance to corrosion are required. Plastic sheet piles, such as sheet piles made of PVC or PVC-based material, are highly resistant to corrosion, making them ideal for use in marine environments, coastal areas, or places with aggressive chemical exposure, where steel might corrode over time. Compared to steel or concrete, PVC sheet piles are significantly lighter, making them easier to transport, handle and install. This reduces overall construction costs and the need for heavy machinery. PVC sheet piles are also considered a more environmentally friendly option due to their longer lifespan and the fact that they can be recycled at the end of their use. While PVC sheet piles are not as strong as steel, they still offer good durability for applications where they are subject to lower loads, such as groundwater barriers or soil retention in less demanding conditions. PVC sheet piles also tend to be more affordable than steel or concrete piles, both in terms of material costs and installation expenses.

[0008] Sometimes, in order to facilitate driving the sheet pile into the ground, the sheet pile panel may be finished with a sharp tip, sharp rods or another similar structures.

[0009] Many types of sheet piles are known in the art, made of various materials and sometimes provided with various types of reinforcing elements.

[0010] For example, Chinese patent application CN113481969A discloses a bank protection plastic-steel sheet pile having a slotted pipe and a cylinder body respectively fixed on both sides of the sheet pile, and having a guide with a bolt with a cone fixed on top of the bolt to facilitate alignment clamping. Both ends of the sheet pile are fixed with reinforcement blocks provided with material guide grooves, whereby the reinforcement blocks are arranged along the end contour of the sheet pile. The side of the reinforcement block away from the centre of the sheet pile is narrowed so it can be inserted into the soil smoothly.

[0011] Document JP4817891B2 discloses a sheet pile reinforced with carbon fiber. The cross-sectional shape of the sheet pile has flange portion and a web portion connected to the end portion of the flange portion. Both parts may contain a hollow part, open at both ends of the sheet pile, which serves as a passage for water flow, poured from the top of the sheet pile.

[0012] Document CN112411471B discloses a plastic-steel sheet pile having the fender pile surrounding the sheet pile from the bottom side, and having at the bottom end a bottom plate, arranged in a "V" shape with the tip of the "V" facing downwards, whereby the "V" shape enables the bottom plate to be pressed into the soil more smoothly. The sheet pile also comprises vertical vents through which the outside air enters the space surrounded by the bottom plate and the fender pile, which reduces the possibility of sediment accumulation under the lifted sheet pile.

[0013] However, despite the various reinforcing methods or materials used, sheet piles made of plastic still remain susceptible to environmental conditions, especially to UV radiation. Prolonged exposure to UV radiation can cause PVC to degrade over time. This can be mitigated by using UV-stabilized materials, but such materials are more expensive in manufacturing and their production requires more workload. Moreover, the main raw material used for the production of sheet piles is PVC recyclate from window frames, facade panels, etc. As a result of the recycling process, in addition to high-impact PVC, the recyclate also contains soft PVC from gaskets. Such a composition of regranulates causes the Vicat softening temperature to often drop to a value below the acceptable value for this type of products. With long-term exposure to solar radiation and heating of the surface, shape deformation often occurs. The known state of the art does not eliminate said problem of shape deformation.Object and summary of the invention

[0014] The object of the present invention is to provide a sheet pile resistant to UV radiation, which does not deform or degrade over time due to prolonged exposure to UV radiation, and which loses preferable mechanical properties, such as creep strength and appropriate Young's modulus, to a lesser extent. The object of the present invention is also to provide a sheet pile that is not easily damaged when being inserted into the ground, despite being made entirely of plastic material.

[0015] The object of the invention has been achieved by providing an elongated sheet piling panel having the features according to claim 1.

[0016] According to the invention, there is provided a plastic sheet piling panel having an elongated body of constant shape along its length, comprising two opposite side edges having interlocking formations for connecting the side edges of adjacent panels together along their lengths, a top end, and a bottom end for driving the panel into the substrate, and a first wall and a second wall arranged parallelly to each other.

[0017] The first wall and the second wall are connected by partitions extending between said walls inside the panel and oriented along the length of the panel, from the top end to the bottom end of the panel, thereby forming hollow chambers extending longitudinally from the top end to the bottom end of the panel. The air contained in the chambers of the sheet piling panel acts as a thermal insulator, what allows the temperature of the wall regions which are not exposed to solar radiation to be lowered enough to prevent deformation of the panel.

[0018] At the bottom end of the panel the chambers are closed, so that the chambers have no outlet at said bottom end. Closing the chambers at the bottom end of the panel allows to prevent the substrate from entering into the chambers during insertion, and thus prevents damaging the chambers.

[0019] Preferably, the bottom end of the panel is formed as a sharp tip having a shape of an acute angle, with a decreasing cross section towards its end. This allows to facilitate insertion of the sheet piling panel into the substrate.

[0020] Preferably, the bottom end of the panel is shaped by thermoforming.

[0021] Preferably, one of said oppositely extending side edges has a male interlocking formation and the other one of said side edges has a matching female interlocking formation, having complementary size and shape to surround and lock with said male locking formation.

[0022] Alternatively, the oppositely extending side edges have Larssen type interlocking formations.

[0023] Alternatively, the oppositely extending side edges have thumb and finger type interlocking formations.

[0024] Preferably, the module has a first flange wall segment, a second flange wall segment and a straight middle wall segment connected with said first and second wall segments by bent regions, whereby said first and second flange wall segments form obtuse angles with the middle wall segment, such that the panel has a stretched Z-shaped cross section.

[0025] Alternatively, the module has a first flange wall segment, a second flange wall segment and a middle wall segment connected with said first and second wall segments by bent regions, whereby the middle wall segment has two bent regions having obtuse internal angles, such that the panel has an U-shaped cross section.

[0026] Alternatively, the module is a box-type sheet piling panel, having a box-like cross-section, or a H-shaped sheet piling panel, having two parallel walls joined by a wall perpendicular to them, or an arch-shaped sheet piling panel, having a curved or arched cross-section.

[0027] Alternatively, the panel has a first flange wall segment, a second flange wall segment and a polygon-shaped structure between said first and second wall segments.

[0028] Alternatively, the first flange wall segment and the second flange wall segment have different widths.

[0029] Alternatively, the panel is a flat-web sheet piling panel, having a straight cross-section.

[0030] Alternatively, the chambers are provided in the straight parts of the panel.

[0031] Preferably, the panel is made of PVC or PVC-based material.

[0032] According to the invention there is also provided a plurality of sheet piling panels each having the features of claim 1, connected into a tight sheet piling wall.Brief description of the drawings

[0033] The present invention will be described in detail in relation to the attached drawings, in which: Fig. 1 depicts a schematic cross-sectional view of an U-shaped sheet piling panel; Fig. 2 depicts a schematic cross-sectional view of an Z-shaped sheet piling panel; Fig. 3 depicts a schematic cross-sectional view of an custom-shaped sheet piling panel; Fig. 4 depicts the sheet piling panel of Fig. 3 in front view and in cross-section through the polygon-shaped structure of the panel; Fig. 5 depicts the sheet piling panel of Fig. 3 in orthogonal view, from the side of the top end of the panel; Fig. 6 depicts the sheet piling panel of Fig. 3, in orthogonal view, from the side of the bottom end of the panel; Fig. 7 depicts a schematic cross-sectional view of a sheet piling wall made of two sheet piling panels according to Fig. 3. Detailed description

[0034] Sheet piles come in various shapes and profiles, each designed to optimize their performance for different engineering applications. The shape of a sheet pile affects its strength, interlocking ability, and suitability for specific types of construction. The present invention is applicable to various shapes of sheet piles, i.e. the sheet pile according to the invention may have any shape which is appropriate for specific use, since the essence of the invention is providing the chambers between the walls of the sheet pile, irrespectively of their shape.

[0035] During use, the sheet piling panels are mostly covered by the ground surrounding its walls, but top regions of the sheet piling panels are exposed to the surface and thus are exposed to UV radiation and heat. Therefore, top and bottom parts of each sheet piling panel have different temperatures, and that causes its deformations.

[0036] The object of the invention is therefore to prevent degradation of plastic sheet pile due to prolonged exposure to UV radiation and heat. The object of the invention has been achieved by providing a sheet piling panel having chamber structure, i.e. having multiple longitudinal chambers 6 separated from each other by partitions 5 and extending along the whole length of the panel. The partitions 5, also referred to as inner walls, are arranged between the chambers 6 and are provided in order to strengthen the structure of the sheet piling panel.

[0037] The sheet piling panel according to the invention will be described below in greater detail with reference to the attached Figures depicting three exemplary embodiments of the panel, which differ in the cross-sectional shape as will be described later below. The sheet piling panel according to the invention is made of plastic, preferably of PVC, PVC recyclate or of other PVC-based material.

[0038] A plastic sheet piling panel according to the invention has an elongated body of constant shape along its length, whereby the length L of the panel is significantly bigger than its width W. This is shown for example in Fig. 4.

[0039] As depicted in Fig. 1 to Fig. 3, the sheet piling panel has two opposite side edges 1a, 1b having interlocking formations for connecting the side edges 1a, 1b of adjacent modules together along their lengths. In the shown embodiment, the first side edge 1a has a female configuration and the second side edge 1b has a male configuration, the female locking formation having complementary size and shape to surround and lock with said male locking formation. However, any other type of interlock can be used at the edges 1a, 1b, what will be described later below.

[0040] As depicted in Fig. 4, the sheet piling panel has a top end 2 and a bottom end 3. The bottom end 3 is the end intended for driving the panel into the substrate, such as ground.

[0041] The sheet piling panel has double walls allowing to form chambers inside, and therefore has a first wall 4a and a second wall 4b, arranged parallelly to each other. The first wall 4a and the second wall 4b are connected by partitions 5 extending between said walls 4a,4b inside the panel. Preferably, the partitions 5 are arranged perpendicularly to said walls 4a, 4b. The partitions 5 are oriented along the length L of the panel, from the top end 2 to the bottom end 3 of the panel, thereby forming hollow chambers 6 extending longitudinally from the top end 2 to the bottom end 3 of the panel (and, in the obvious manner, also oriented along the length L of the panel).

[0042] The air contained in the chambers 6 of the sheet piling panel according to the invention acts as a thermal insulator. This allows the temperature of the wall regions which are not exposed to solar radiation (closer to the bottom end 3) to be lowered enough to prevent deformation and thus eliminate this unfavourable phenomenon. The lowered temperature of the sheet piling panel in said regions causes a smaller loss of mechanical properties, such as Young's modulus and creep strength, which are key in sheet pile structures made of PVC.

[0043] The use of a sheet pile having multiple elongated, vertical chambers 6 separated by partitions 5 is associated with an increased frontal resistance area when driven into the ground, due to which a good mechanical strength of the structure is obtained. Thanks to such a structure, the sheet piling panel is not easily damaged during insertion into the ground.

[0044] In the simplest embodiment, the chambers 6 may be open both from the top side 2 as well as from the bottom side 3 of the panel.

[0045] To sum up, a sheet pile according to the invention has chamber structure, which means that it has double wall divided into multiple chambers 6 (compartments) which are separated from each other by partitions 5. The sheet piling panel thus has two walls 4a, 4b which are connected by substantially perpendicular partitions 5, forming hollow chambers 6 extending longitudinally from the top end 2 to the bottom end 3 of the pile. The partitions 5 allow to strengthen the structure of the sheet pile.

[0046] There occurs a risk that the soil entering the chambers 6 during insertion into the substrate may cause them to burst. According to that, the substrate (such as ground or soil) should be prevented from entering into the chambers 6 and thus damaging them.

[0047] Therefore, there is provided a sheet piling panel in which the chambers 6 are closed at the bottom end 3, i.e. at the side which first comes in contact with the substrate during insertion. Thus, in preferable embodiment, at the bottom end 3 of the panel the chambers 6 are closed, so that said chambers 6 have no outlet at said bottom end 3 of the panel, what prevents the soil from entering the chambers 6.

[0048] Since the sheet piling panel is made of plastic, the most convenient way of forming and thus closing the chambers 6 is thermoforming. The plastic material of the walls 4a, 4b at the bottom end 3 of the sheet piling panel are thermally welded, and thus sealing of the chambers 6 is achieved. In other words, the opposite ends of the walls 4a, 4b at the bottom side 3 of the panel are fused to close and seal the chambers 6 at this bottom side 3, and in the result the chamber 6 structure at this bottom end 3 is eliminated.

[0049] As depicted in Figs. 1 to 5, in order to further facilitate the insertion of the sheet piling panel into the ground, the bottom part 3 of the panel may be formed as a sharp tip 7. Closing the bottom end 3 of the sheet piling panel eliminates the chamber 6 structure at this bottom end 3, as mentioned above. By fusing the outer walls 4a, 4b into a sharp tip 7, the frontal drag is minimized and insertion of the sheet piling panel into the substrate is facilitated. As shown in Figs. 1 to 3, the tip 7 has a decreasing cross-section A-A towards the bottom end 3 of the panel, whereby the bottom end 3 of the panel is the one which comes in contact with the substrate during insertion. In other words, the cross-section A-A of the double wall (composed of first and second walls 4a, 4b) is smaller at the bottom end 3 of the panel, and in longitudinal cross-section the bottom end 3 of the panel is formed as an V-shaped, acute angle. The sharp tip 7 is preferably made by thermoforming -the walls 4a, 4b in the bottom part 3 of thermoformed to achieve a sharp tip 7.

[0050] Preferably, the temperature range for thermoforming of the sheet piling panel's material is between 90°C and 200°C.

[0051] Fig. 5 depicts the sheet piling panel of Fig. 3 in orthogonal view, from the side of the top end 2 of the panel. As shown in Fig. 5, the chambers 6 at the top end 2 of the panel are open. Thanks to that the surrounding air can enter the chambers 6. Fig. 6 depicts the sheet piling panel of Fig. 3, in orthogonal view, from the side of the bottom end 3 of the panel. As shown in Fig. 5 and more precisely in Fig. 6, the chambers 6 at the bottom end 3 of the panel are closed, so that during insertion into the substrate, the substrate cannot enter into the chambers 6. The chambers 6 are closed preferably by thermoforming. As shown in Fig. 5,6, the bottom end 3 may be formed into the sharp tip 7. The sharp tip 7 is also shown in Fig. 4, in the cross-section B-B through the sheet piling panel.

[0052] In the most simple embodiment (not depicted), the sheet piling panel has a straight cross-section and thus is formed as a flat sheet, having interlocking formations provided on its both distal side edges 1a, 1b. In the embodiments depicted in the Figures 1 to 7, the sheet piling panel has more complex shape, due to the presence of bent regions 10. Three exemplary shapes of the sheet piling panel according to the invention will be described below. However, the possible shapes are not limited to these presented herein.

[0053] One of the most common profiles are U-shaped sheet piling panels. U-shaped sheet piling panel is presented in Fig. 1 and has a symmetrical, U-shaped cross-section with interlocking formations provided on opposed side edges 1a, 1b of the panel. The first side edge 1a has a female configuration and the second side edge 1b has a male configuration, however any type of interlock can be used at the edges 1a, 1b. In other words, the U-shaped sheet piling panel has a hollow and substantially rectangular shape (possibly, with slightly inclined walls) in longitudinal cross section. In yet another words, the U-shaped profile has a first flange wall segment 8a and a second flange wall segment 8b which are connected by a middle wall segment 9 having substantially rectangular or trapezoidal shape. The first flange wall segment 8a and the second flange wall segment 8b may have the same or different widths. In Fig. 1, flange wall segments 8a, 8b have different widths. The middle wall segment 9 has two bent portions 10, whereby the internal angles of the middle wall segment 9 are obtuse. The middle wall segment 9 is connected to the first flange wall segment 8a and to the second flange wall segment 8b by another two bent portions 10. On the side remote from the middle wall segment 9, the straight flange wall segments 8a, 8b lead to the interlocking formations of the side edges 1a, 1b. According to Fig. 1, the first flange wall segment 8a has two chambers 6 divided by one partition 5, the second flange wall segment 8b has one chamber 6, and the middle wall segment 9 has five chambers 6 in the central part and three chambers 6 in each side part. These type of piles can be driven into the ground either singly or joined, providing flexibility during installation.

[0054] Another common sheet pile type is Z-shaped sheet pile. Z-shaped sheet pile is presented in Fig. 2. Z-shaped sheet piles are shaped roughly like a horizontally stretched Z, and have a Z-like cross-section where the middle of the panel is offset to create a zigzag shape. The panel is provided with interlocking formations provided on opposed side edges 1a, 1b of the panel. The first side edge 1a has a female configuration and the second side edge 1b has a male configuration. Z-shaped sheet piling panel thus has a first flange wall segment 8a, a second flange wall segment 8b, and a middle wall segment 9 between said first and second wall segments 8a, 8b. Said first and second flange wall segments 8a, 8b are connected to the middle wall segment 9 at an obtuse angle. The first flange wall segment 8a and the second flange wall segment 8b may have the same or different widths. In Fig. 2, flange wall segments 8a, 8b have different widths. In another words, said flange wall segments 8a, 8b and said middle wall segment 9 define a substantially stretched Z-shaped cross section. The Z-shaped sheet piling panel has thus two bent regions 10 respectively curving in opposite directions, whereby the middle wall segment 9 is connected to the first flange wall segment 8a and to the second flange wall segment 8b by bent regions 10. On the side remote from the middle wall segment 9, the straight flange wall segments 8a, 8b lead to the interlocking formations of the side edges 1a, 1b. According to Fig. 2, the first flange wall segment 8a has three chambers 6, the second flange wall segment 8b has four chambers 6, and the middle wall segment 9 has six chambers 6.

[0055] Sheet piles may also have another, non-standard shapes, such as for example a shape presented in Fig. 3, Fig. 4, Fig. 5, and Fig. 6. In this embodiment, the sheet piling panel is a hollow walled sheet piling profile with non-symmetrical, polygon-shaped functional chamber. The sheet piling panel thus has a polygon-shaped structure 11 instead of the middle wall segment 9, whereby the polygon-shaped structure 11 resembles a tube and forms a functional chamber. The panel is provided with interlocking formations provided on opposed side edges 1a, 1b of the panel. The first side edge 1a has a female configuration and the second side edge 1b has a male configuration. The sheet piling panel has a first flange wall segment 8a, a second flange wall segment 8b, and the polygon-shaped structure 11 arranged between said first and second flange wall segments 8a, 8b. Said first and second flange wall segments 8a, 8b are connected to the polygon-shaped structure 11 preferably at an right angle. The first flange wall segment 8a and the second flange wall segment 8b may have the same or different widths. In Fig. 3, flange wall segments 8a, 8b have different widths. as depicted in Fig. 3. The polygon-shaped structure 11 is made of wall segments forming a hollow space between them, the wall segments being joined by bent regions 10. In the shown embodiment, the polygon-shaped structure 11 has six wall segments and thus has a hexagonal cross section. One segment is located at the same plane as the flange wall segments 8a, 8b, thereby forming a flat surface with them. Another segment of the polygon-shaped structure 11 is parallel to the flange wall segments 8a, 8b, another two segments are perpendicular to the flange wall segments 8a, 8b, whereby the remaining another two wall segments are located between said perpendicular segments and said segment parallel to the flange wall segments 8a, 8b, and is joined with them at obtuse angles, thereby forming bent regions 11. On the side remote from the polygon-shaped structure 11, the straight flange wall segments 8a, 8b lead to the interlocking formations of the side edges 1a, 1b. Into the polygon-shaped structure 11 various reinforcing elements may be inserted, such as poles or pillars made of steel or plastic, in order to additionally reinforce the sheet piling panel. According to Fig. 3, the first flange wall segment 8a has three chambers, the second flange wall segment 8b has six chambers 6, and the polygon-shaped structure 11 has ten chambers 6 (two segments having two chambers 6, three segments each having one chamber 6 and one segment having three chambers 6). In exemplary embodiment, the second flange wall segment 8b is divided in the middle by divider 12, which does not have any chamber 6, and thus the second flange wall segment 8b has two sections, each having three chambers 6. The dividers 12 have purely aesthetic function and are not necessary in any embodiment. Figure 4 shows a side view of the sheet piling panel having a shape presented in Fig. 3, from the side of the polygon-shaped structure 11. Fig. 4 also shows a cross-section B-B of the sheet piling panel through the polygon-shaped structure 11.

[0056] Another type of sheet piling panels, not shown in the figures, is a flat-web (also referred to as a straight-web) sheet pile. Flat-web sheet piles have a flat, straight cross-section with simple interlocking formations on the edges, and have no bent portions. They are mostly formed in circles and arcs to create gravity cells held together through the tensile strength of the interlock. They are generally used in applications where bending stresses are lower. Therefore, in the most simple embodiment of the invention, the sheet piling panel is formed as a flat sheet, having interlocking formations provided on its both distal side edges. However, typical sheet piling panels have folds or angles, referred herein as to bent portions 10, to provide nonlinear cross-sections for increased stiffness.

[0057] Yet another type of sheet piles, also not shown in the figures, is a box-shaped sheet pile. Box-shaped sheet piles are formed as two U-shaped profiles welded together to form a box-like cross-section (typically having a shape of a hexagon or a square-like shape). This design significantly increases the pile's moment of inertia. It is also known to weld together more than two U-shaped profiles, thus creating more complex shapes. The box shape provides exceptional resistance to bending and shear forces. Therefore, these piles are suitable for situations where very high strength is required.

[0058] There are also known H-shaped sheet piles, having two parallel walls joined by a wall perpendicular to them, or hat-shaped sheet piles, resembling U-shaped profiles having perpendicular wall attached to the middle wall and extending to the outside of the U letter, or arch-shaped sheet piles, having a curved or arched cross-section. Generally, the possible shapes of sheet piles are well known to the person skilled in the art.

[0059] As mentioned above, sheet piling panels are elongated, and thus have length L much greater than width W, as shown for example in Fig. 4. The sheet piling panel has dimensions depending on the requirements. Typically, length of the sheet piling panel is up to 3 m. For example, the sheet piling panel may have length of 1,8 m and width of 60 cm.

[0060] Except for the flat sheet piles, the sheet piles in general are not straight and have corners, referred herein as to bent regions 10. The corners of the sheet piles should be especially strong and rigid, and thus these places are preferably not equipped with chambers 6. In other words, the chambers 6 are concentrated in straight parts of the sheet piling panel. Moreover, the sheet piling panel having double wall (first and second walls 4a, 4b) and a chamber 6 in the corner would be difficult in manufacturing. Therefore, each corner (bent region 10) of the sheet pile is preferably provided with partition 5. More preferably, the partitions 5 in the bent regions have a form of a wide filling material, thicker than each partition 5 provided in the straight parts of the panel. The dimensions of the partitions 5 in the corners varies since it is dependent for example on the angle at which the corner is bent and also on the required rigidity of the sheet pile. For example, in Fig. 1 (U-shaped sheet pile), the partition in the bent region 10 has similar width to the width of the chamber 6, whereby in the embodiments depicted in Fig. 2 and Fig. 3 the width of the partition in the bent region 10 substantially corresponds to the radius of the bent region 10.

[0061] The chambers 6 of the sheet piling according to the invention, except acting as a thermal insulator, may be used to introduce reinforcing elements, allowing to strengthen the structure of the sheet piling panel. For example, reinforcing elements such as steel flat bars may be introduced into the chambers 6.

[0062] The connector parts of sheet piles, often referred to as interlocks or clutches, are integral features that allow individual sheet piling panels to be locked together at their distal edges to form a continuous wall. There are various types of interlocks which are well known to the person skilled in the art. The specific design of the connectors varies depending on the type of sheet pile and its intended application. There are no established industry standards for interlocks, however manufacturers have the same objectives for the interlocks: they should provide permanent connection of individual sheets forming a continuous, relatively water or earth tight wall; they should permit reasonably free sliding during installation; and they should meet the appropriate strength requirements. The present invention is obviously applicable to any type of interlocks, however, for the sake of clarity, the most common types of interlocks will be discussed briefly below.

[0063] The Larssen interlock is one of the most common types, originally developed for steel sheet piles. It features a hook-and-grip mechanism where the protruding edge of one pile hooks into the receiving edge of the adjacent pile. Adjacent sheet piles interlock to form a wall with alternating indents and outdents, since Larssen interlocks cause that each segment is flipped 180° versus the preceding segment.

[0064] Thumb and finger interlock design, typically used on flat sheet piles, resembles a thumb fitting into a slot, with one sheet pile having a protruding "thumb" and the other a receiving "finger" slot - the thumbs of opposing profiles are threaded into the sockets formed by the thumb and curved finger.

[0065] The typical interlock type is also an interlock having male and female connectors, which are located at opposite sides of the sheet pile. One specific type of this interlock is also for example a ball and socket interlock, featuring a ball-shaped end on one panel and a corresponding socket on the adjacent panel. The ball fits into the socket, creating a strong and flexible connection.

[0066] The adjacent sheet piles may also be joined by separate connector elements, fitting into various types of connectors formed on the side edges of the sheet piles.

[0067] In the embodiments shown in the Figures 1 to 7, the sheet piling panel is equipped with an interlock having male and female connectors. The individual panels thus have first side edges 1a equipped with female formations and second side edges 1b equipped with corresponding male formations. The male and female formations arranged along the lengths of said edges 1a, 1b.

[0068] Figure 7 shows two sheet piling panels according to the embodiment depicted in Fig. 3, connected with each other by side edges 1a, 1b having male-female interlocks. To form a tight wall, multiple sheet piling panels are connected to each other. Plurality of elongated sheet piling panels, in obvious manner, may be connected into a continuous sheet piling wall by any interlocking formations arranged on side edges 1a, 1b of each panel.

[0069] The width and thickness of the chambers 6, as well as the width of the partitions 5, may vary since it depends on the parameters required for the specific sheet piling panel. However, in an exemplary embodiment, the partitions 5 which are placed in the straight sections of the panel's walls may be 2,2 mm wide. Preferably, at the bending points 10 the partitions 5 are wider than 2,2 mm. The width of each chamber may be for example 7 mm (which corresponds to the length of the partitions 5). The length of each chamber 6, in the plane of the cross-section as shown in Figs. 1 to 3, may vary in each segment of the sheet piling panel and even may vary within the same segment, but preferably is bigger than its width (which is, as said above, for example 7 mm). Each wall 4a, 4b may have for example a thickness of 2 mm to 3 mm, preferably 2,5 mm. Internal width of the polygon-shaped structure 11, between its parallel segments, may be for example 160 mm x 160 mm.

Claims

1. A plastic sheet piling panel having an elongated body of constant shape along its length, comprising: two opposite side edges (1a, 1b) having interlocking formations for connecting the side edges (1a, 1b) of adjacent panels together along their lengths; a top end (2), and a bottom end (3) for driving the panel into the substrate; a first wall (4a) and a second wall (4b) arranged parallelly to each other, characterized in that the first wall (4a) and the second wall (4b) are connected by partitions (5) extending between said walls (4a, 4b) inside the panel and oriented along the length of the panel, from the top end (2) to the bottom end (3) of the panel, thereby forming hollow chambers (6) extending longitudinally from the top end (2) to the bottom end (3) of the panel, and in that at the bottom end (3) of the panel the chambers (6) are closed, so that the chambers (6) have no outlet at said bottom end (3).

2. A plastic sheet piling panel according to claim 1, wherein the bottom end (3) of the panel is formed as a sharp tip (7) having a shape of an acute angle, with a decreasing cross section (A-A) towards its end.

3. A plastic sheet piling panel according to claim 1 or 2, wherein the bottom end (3) is shaped by thermoforming.

4. A plastic sheet piling panel according to any of the preceding claims, wherein one of said oppositely extending side edges (1b) has a male interlocking formation and the other one of said side edges (1a) has a matching female interlocking formation, having complementary size and shape to surround and lock with said male locking formation.

5. A plastic sheet piling panel according to any of the preceding claims, wherein the oppositely extending side edges (1a, 1b) have Larssen type interlocking formations.

6. A plastic sheet piling panel according to any of the claims from 1 to 4, wherein the oppositely extending side edges (1a, 1b) have thumb and finger type interlocking formations.

7. A plastic sheet piling panel according to any of the preceding claims, wherein the module has a first flange wall segment (8a), a second flange wall segment (8b) and a straight middle wall segment (9) connected with said first and second wall segments (8a, 8b) by bent regions (10), whereby said first and second flange wall segments (8a, 8b) form obtuse angles with the middle wall segment (9), such that the panel has a stretched Z-shaped cross section.

8. A plastic sheet piling panel according to any of the claims from 1 to 6, wherein the module has a first flange wall segment (8a), a second flange wall segment (8b) and a middle wall segment (9) connected with said first and second wall segments (8a, 8b) by bent regions (10), whereby the middle wall segment (9) has two bent regions (10) having obtuse internal angles, such that the panel has an U-shaped cross section.

9. A plastic sheet piling panel according to any of the claims from 1 to 6, wherein the module is a box-type sheet piling panel, having a box-like cross-section, or a H-shaped sheet piling panel, having two parallel walls joined by a wall perpendicular to them, or an arch-shaped sheet piling panel, having a curved or arched cross-section.

10. A plastic sheet piling panel according to any of the claims from 1 to 6, wherein the panel has a first flange wall segment (8a), a second flange wall segment (8b) and a polygon-shaped structure (11) between said first and second wall segments (8a, 8b).

11. A plastic sheet piling panel according to any of the preceding claims, wherein the first flange wall segment (8a) and the second flange wall segment (8b) have different widths.

12. A plastic sheet piling panel according to any of the claims from 1 to 6, wherein the panel is a flat-web sheet piling panel, having a straight cross-section.

13. A plastic sheet piling panel according to any of the preceding claims, wherein the chambers (6) are provided in the straight parts of the panel.

14. A plastic sheet piling panel according to any of the preceding claims, wherein the panel is made of PVC or PVC-based material.

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