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TECHNICAL FIELD  
       [0001]     This invention relates generally to retaining walls, and more specifically to retaining walls for use in controlling land erosion in contact with water.  
       BACKGROUND OF THE INVENTION  
       [0002]     Over the many years, there has long existed the problem of land erosion adjacent waterways, rivers, lakes and oceans wherein seawalls of various types have heretofore been constructed of wood, steel or cement. Heretofore, efforts have been made to provide a series of seawall elements which are laterally aligned and in some manner interconnected and pounded down into the ground and anchored. Illustrative of earlier prior art efforts to provide a seawall, constructed of reinforced concrete, is U.S. Pat. No. 1,332,655 issued to R. B. Willard in 1920. The problem then as recognized by the inventor and thereafter, has been the enormous pressures and loads applied to the seawall which have ultimately destroyed the connection between adjacent seawall elements to render the seawall less than effective and ultimately requiring replacement and repairs.  
         [0003]     It is known to form seawalls of a plurality of panels formed of extruded PVC material and interconnected edge to edge, as shown in Berger, U.S. Pat. Nos. 4,674,921 issued Jun. 23, 1987 and 4,690,588 issued Sep. 1, 1987. In Berger, panel strips of corrugated or sinusoidal shape are formed with alternating groove edges and tongue edges, permitting the panels to be interlocked along their vertical marginal edges. Wale elements are mounted along outer surfaces of the panel strips and accept tie bolts or tie rods extending to ground anchors on the opposite side of the seawall. Berger also discloses angled strips for making corners, and connectors for joining adjacent strips in edge-to-edge relation.  
         [0004]     Sinusoidal or corrugated sheets have been mounted in facing relation and connected or joined by tie rods, and the spaces therebetween have been filled with concrete or mortar to provide a water-tight joint, to form a revetment, as shown in Schneller, U.S. Pat. No. 3,247,673 of Apr. 26, 1966.  
         [0005]     Sinusoidal or corrugated panel sections have been used to make up retaining walls or seawalls, with wale elements on a front surface tied back to anchors, as shown in a number of prior patents. Caples, U.S. Pat. No. 1,947,151 of Feb. 13, 1934 shows panel sections formed with interconnecting locking vertical edges in alternating inwardly and outwardly directed portions to form a sinusoidal wall. In Caples, the interlocking ends are identical. In Frederick, U.S. Pat. No. 3,822,557 of Jul. 9, 1974, one panel vertical edge is formed with a tongue and the opposite panel vertical edge is formed with a groove proportioned to receive the tongue of an adjacent panel.  
         [0006]     Another example of a retaining wall made of interlocking sections of sheet material is McGrath, U.S. Pat. No. 2,968,931 of Jan. 24, 1961. In McGrath each panel section is bent into three angular portions, and each panel section is reversed when connected, edge to edge to form a sinusoidal-like pattern.  
         [0007]     Earlier examples of wall systems having interlocking panel sections which are assembled in longitudinal alignment, with interlocking vertical edges, include Clarke, U.S. Pat. No. 972,059 of Oct. 4, 1910; Boardman et al, U.S. Pat. No. 1,422,821 of Jul. 18, 1922; and Stockfleth, U.S. Pat. No. 1,371,709 of Mar. 15, 1921.  
         [0008]     It is also known to use a series of individual arcuate sections which are then joined or interconnected to form a retainer wall, as shown in Van Weele, U.S. Pat. No. 4,407,612 of Oct. 4, 1983.  
         [0009]     While walls formed by corrugated panel sections are extensively shown in the prior art in which the corrugations or the axes of the corrugations run vertically, is also known to form panel sections in which the axes of the corrugations run horizontally, as shown in Sivachenko U.S. Pat. No. 4,099,359 of Jul. 11, 1978.  FIGS. 7 and 8  also show opposed facing pairs of corrugated sections in which the spaces therebetween may be filled with concrete to form a revetment.  
         [0010]     It is common to use wale brackets or wale elements in combination with panel-type seawalls or retainer walls. Berger, Schnabel, Jr. and Caples show wale elements in longitudinal alignment. Schnabel, Jr., U.S. Pat. No. 3,541,798 of Nov. 24, 1970 shows individual longitudinally spaced wale elements along the wall front face. The wale elements receive tie-back rods, which rods extend through or between the panels to suitable anchors.  
         [0011]     Essentially two-dimensional polymeric retaining wall members with interlocking members along the edges that are universally mateable to like members are illustrated in U.S. Pat. No. 4,863,315, issued Sep. 5, 1989 to Wickberg while a wall system which employs a plurality of individual panels formed of extruded polymer joined in edge-to-edge relation including wale members which are vertically offset and interlocked at end portions thereof with adjacent wale members is shown in U.S. Pat. No. 4,917,543, issued Apr. 17, 1990 to Cole et al.  
         [0012]     A shoreline erosion prevention bulkhead system which employs a series of interlocking fiberglass panels is shown in U.S. Pat. No. 5,066,353 issued Nov. 19, 1991, to Bourdo while a plastic structural panel and ground erosion barrier is illustrated which in general is a stretched Z-shaped cross-sectional design with opposed male and female interlock edges for mating association with adjacent panel strips in U.S. Pat. No. 5,145,287 issued Sep. 8, 1992 to Hooper et al.  
         [0013]     Corner adapters for use with corrugated barrier sections are disclosed in U.S. Pat. No. 5,292,208 issued Mar. 8, 1994 to Berger and a sheet piling extrusion with locking members is illustrated in U.S. Pat. No. 6,000,883 to Irving et al. A reinforced Z-shaped configuration of the same with strengthening ribs is illustrated in U.S. Pat. No. 6,033,155 issued Mar. 7, 200 to Irvine et al. A generally U-shaped seawall panel is disclosed in U.S. Pat. No. 6,575,667 issued Jun. 10, 2003 to Burt et al.  
         [0014]     This invention was developed to continue to advance the state-of-the-art for retaining walls, particularly extruded polyvinyl chloride (PVC) retaining walls which offer easier installation and greater structural integrity than those found in the Prior Art.  
       SUMMARY OF THE INVENTION  
       [0015]     It is an aspect of the present invention to provide a modular barrier or retaining wall, particularly for use in tidal environments where land erosion is a particular problem.  
         [0016]     It is another aspect of the invention to provide a modular barrier wall which utilizes linear U-shaped (optionally polygon-shaped—whether open or closed polygon) channel modules and angled (optionally polygon-shaped—whether open or closed polygon) channel modules which through mating engagement of male projections and female receptacles, effect wall construction which is self-aligning.  
         [0017]     It is still yet another aspect of the invention to provide a modular retaining wall which permits wall construction to angle either outward or inward by inserting the appropriate end of an angled module, the angled module being essentially a mirror-image of each other as viewed through a bisecting horizontal line through the angled module.  
         [0018]     It is a further aspect of the invention to improve on existing seawall “sheet pilings” of plastic material by exposing a smooth face toward both the sea and the land using a substantially rigid three-dimensional structure which employs a double connection system which is locked into a fixed location. A connection hook is employed which allows for clearing of external material during installation. The final structure is hollow and can be filled with gravel, concrete, etc., to achieve a higher strength. The smooth surfaces are not only more visually appealing, but also make installation easier due to the ease of concrete form construction. Additionally, angled modules are provided which allow for a radiused appearance.  
         [0019]     It is still a further object of this invention to employ a two point connection that makes for faster installation because the three-dimensional profile cannot twist or bow to the degree of existing two-dimensional products. This means less driving energy will be absorbed by the pile making it faster to drive. It also reduces rework required to correct misplaced piles in that they will not have to be withdrawn and replaced.  
         [0020]     To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:  
         [0022]      FIG. 1  is a perspective view of the modular retaining wall illustrating a 45° bend interposed therein with end caps positioned at opposed ends of the wall;  
         [0023]      FIG. 2  is a top plan view of one module of  FIG. 1 ;  
         [0024]      FIG. 3  is a top plan view of  FIG. 1 ;  
         [0025]      FIG. 4  is a top plan view of an embodiment of the modular retaining wall illustrating the incorporation of a middle retaining rib and a different linking geometry;  
         [0026]      FIGS. 5-7  are top plan views of alternative embodiment of the modular retaining wall illustrating alternative linking geometries including middle side wall support;  
         [0027]      FIG. 8  is a top plan view of closed polygonal shaped modules for use in an embodiment of the retaining wall;  
         [0028]      FIG. 9  is a top plan view of an end or middle module of the modular retaining wall illustrating the open polygon shape; and  
         [0029]      FIG. 10  is a top plan view of an end module of the retaining wall illustrating the closed polygon shape. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     The invention is described with reference to the accompanying figures, which illustrate the best mode known to the inventor at the time of the filing of the application illustrating the modular retaining wall of the invention.  
         [0031]     As better illustrated in  FIG. 1 , retaining wall  10  consists of various modules which form a contiguous barrier wall across a length of the modules when in their assembled state. Some modules are essentially interlocking linear U-shaped channels, e.g.,  12   a,    12   b,  and  12   c  whereas other interlocking modules, e.g., angled module  14 , are used to impart non-linearity to the wall. As illustrated in the figure, the imparted angle is approximately 45°, although this is but an example of any angle between 1° and 180°, the end-use application, which in an aqueous environment will be the shoreline defining the requisite angularity required for the non-linear modules. The combination of linear U-shaped modules with non-linear modules provides essentially limitless geometries for retaining wall  10 . At each end of the wall, is an end-cap  16 ,  18 , with an appropriate geometry so as to interlock or mate with its adjacent module, whether that module is linear or angled.  
         [0032]     As better illustrated in  FIG. 2 , a combination of one linear U-shaped channel module  12   a  with adjacent angled channel  14  with respective end caps  16 ,  18  is shown in an unassembled state. Linear module  12   a  is comprised of a pair of essentially parallel vertically-extending sides  20  in connected engagement with an essentially vertical third side  24  positioned normal to the vertical plane of sides  20  at one end of each side  20  forming an essentially open “U-shaped” channel  66  within module  12   a.  Affixed to the exterior of third side  24  and positioned interiorly of each of the ends of the side, is a pair of outwardly facing “J-shaped” or “U-shaped” hook protrusions  26  defining an open longitudinal channel  28 . Affixed to each end of lateral sides  20  at the open end of U-shaped channel  66  are a pair of inwardly facing end wall segments  30 . Spaced apart from end wall segments  30  and penetrating inwardly and curvilinearly toward the open end of the channel are interior curvilinear wall segment protrusions  32 , the combination of end wall segments  30  and interior curvilinear wall segment protrusions  32  defining open vertically-extending longitudinal channel  34 . While curvilinear wall segments  32  are defined as curvilinear, in an alternative embodiment, these segments could be intersecting linear segments, the end-use application defining the need for a geometry which is either curvature-based or intersecting perpendicular line based in a manner similar to that defined for outwardly-facing J-shaped hooks  26 .  
         [0033]     In constructing retaining wall  10 , either a second linear U-shaped channel module  12   b  is attached to the first linear U-shaped channel module  12   a  or a non-linear or angled module  14  is affixed through mating channels and protrusions. As illustrated in  FIG. 2 , a non-linear module  12   b  is shown adjacent to the closed end of linear U-shaped module  12   a.  This angled module, shown to produce an angle of approximately 30°, although both larger and smaller angles are within the scope of this invention, ranging from 1° to 180° are envisioned. Angled module  14  is essentially J-shaped or hook-shaped in which side  44  and curvilinear or curved side  46  intersect, the degree of curvature defined by an angle α (shown to be approximately 45° in the Figure) formed by the intersection of the vertical plane of side  44  and the vertical plane of curvilinear side  46 . In a manner analogous to that discussed with vertical third side  24  of linear module  12   a,  and affixed to the exterior of side  44  and positioned interiorly of each of the ends of this side, is a pair of outwardly facing “J-shaped” hook protrusions  52  defining an open longitudinal channel  62 . Affixed to non-intersecting end of side  44  at the open end of open triangular shaped channel  68  and to non-intersecting end of curvilinear side  46  at the same open end of channel  68  is a pair of inwardly facing end wall segments  48 . Spaced apart from end wall segments  48  and penetrating inwardly and curvilinearly toward the open end of the channel are interior curvilinear wall segment protrusions  50 , the combination of end wall segments  48  and interior curvilinear wall segment protrusions  50  defining open longitudinal channel  54 . While curvilinear wall segments  50  are defined as curvilinear, in an alternative embodiment, these segments could be intersecting linear segments, the end-use application defining the need for a geometry which is either curvature-based or intersecting perpendicular line based in a manner similar to that defined for outwardly-facing J-shaped hooks  26 .  
         [0034]     Attachment of angled module  14  to a linear module, e.g.,  12   a  or  12   b  or  12   c,  is effected by mating engagement of male J-shaped hook protrusion  26  into open female longitudinal channel  54  formed by end wall segments  48  and curvilinear segments  50 . By having mating engagement occur with two channels simultaneously, the modules become self-aligning.  
         [0035]     Retaining wall  10  is constructed by matingly securing linear U-shaped modules  12  and angled modules  14  in combination to meet the geometry required by the end-use application. It is recognized that since the modules are mirror images when dissected through a horizontal plane, that the direction of the turn of the retaining wall through the utilization of an angled module can be in either direction by simply turning the angled module upside-down. At either end of the retaining wall, is an end cap, the configuration of which is dictated by whether the end cap is designed to close an open U-shaped channel or to mate with a pair of outwardly facing J-shaped hooks. In  FIG. 2 , channel closing end cap  16  is constructed with side  36  essentially parallel to third side  24  at the closed end of channel  66 . Spaced inwardly and interiorly of each opposed end  38  of the end cap is a pair of outwardly facing “J-shaped” hook protrusions  40  defining an open longitudinal channel  42 . Attachment of channel closing end cap  16  with linear module  12   a  occurs via mating engagement of male J-shaped hook protrusion  40  into female longitudinal channel  34  formed by end wall segments  30  and curvilinear segments  32 . At the opposed end of retaining wall  10  from channel-closing end cap  16  is terminating cap  18  having a side  56  with a pair of inwardly facing J-shaped hooks  58  at each end with a pair of inwardly facing fingers  60  spaced apart and inward from the pair of J-shaped hooks. Attachment of terminating end cap  18  with angular module  14  occurs via mating engagement of male J-shaped hooks  52  into open female longitudinal channels  64  formed by J-shaped hooks  58  and inwardly facing fingers  60  thereby closing and simultaneously forming channel  70  between side  56  of terminating end cap  18  and side  44  of angled module  14 .  
         [0036]     As illustrated in  FIG. 3 , terminating end cap need not be affixed to angled module  14 , but rather could also terminate a linear U-shaped channel module  12   c.  Attachment of terminating end cap  18  with linear module  12   c  occurs via mating engagement of male J-shaped hooks  26  into open female longitudinal channels  64  formed by J-shaped hooks  58  and inwardly facing fingers  60  thereby capping retaining wall  10 .  
         [0037]     As used in the field and in a preferred embodiment only, subsequent to driving the modules into the seabed using mechanized driving equipment, each closed cavity which is formed through mating engagement with a subsequent module, is filled with pea gravel or concrete or combinations thereof. The filling operation creates outward lateral pressure on each module. For those modules which have relatively small horizontal dimensions, the inherent structural strength of the walls of the module are sufficient to resist any lateral bowing of the module. However, for those modules which have a larger horizontal dimension, e.g.,  12   a,    12   b,    12   c  in the Figures, it is often desirable to include T-shaped (or other geometried) male anchors  72  positioned on opposing side walls  20  on the inside of cavity  66 , thereby forming two separate cavities,  66   a  and  66   b.  This lessens the tendency of the larger modules to lateral bowing when the male anchors  72  are in mating engagement with at least one rib  74  (better illustrated in  FIGS. 5-7 ) which are in mating engagement with the male anchors. While a pair of T-shaped male anchors  72  are illustrated in  FIGS. 4, 6  and shown to be in engagement with a rib  74  having a pair of open oval channels  76   a  positioned at each end of the rib for mating engagement with the male anchors, there is no need to limit the invention to this geometry. As illustrated in  FIGS. 5, 7 , reinforcing rib  74  can mate with male anchors  72   a  (inwardly facing bent finger positioned normal to the vertical plane of wall  20 ) or  72   b  (inwardly facing bent angular finger). When in either of these geometries, it is important that the geometry of the opposed ends  76   b  of reinforcing rib  74  successfully mate or securely or lockingly engage with the male anchor.  
         [0038]     As illustrated in  FIGS. 4-7 , each of the modules can have mating attachment locking mechanisms which employ slightly different geometries, and the invention is not limited to any one geometry. For example, inwardly facing wall segments  30  may be geometried as inwardly facing J-shaped hooks  30   b  which bend backwards 180°, or as inwardly facing J-shaped hooks  30   c  which form an acute angle with wall  20 , said angle ranging from 1-90°, or as outwardly-facing J-shaped hooks  30   d.  Additionally J-shaped hooks  26  may be geometries as outward-facing J-shaped hooks  26   a  which form an acute angle to the initial normal projection from third end wall  24 , said angle ranging from 1-90°, or outward-facing J-shaped hooks  26   b  which bend backwards 180°, or outward-facing J-shaped hooks  26   c  or inward-facing hooks  26   d.  Similarly, inwardly-facing wall segments  48 , namely  48   a,    48   b,    48   c  or  48   d  may be possessed of different geometries, the key being mating or secure or locking engagement with their corresponding J-shaped hooks  26 . Similar comments are pertinent to protrusions  52 , namely  52   a,    52   b,    52   c,  and  52   d  which would need to correspondingly securely or matingly engage with their associated next modular unit.  
         [0039]      FIG. 8  illustrates a further embodiment of the modular retaining wall construction wherein each module is of a closed geometry for additional stability if required by the application. Module  12   a  comprises a closed rectangular polygon having a pair of parallel sides  20  and a pair of connecting ends. End  24   a  simply closes the polygon on one side and is used as a terminating end module to the retaining wall  10 . When used in this configuration, there is no need for end cap  36  as illustrated in  FIG. 3  for example. Opposed end  24  has a pair of outwardly-facing male J-shaped hook protrusions  26  for engagement with inwardly-facing J-shaped hooks of inner module  12   b.  This module is the building block module when the wall is constructed with closed polygon modules. Module  12   b  comprises similar parallel sides  20  with opposed end walls, one end wall having a pair of inwardly-facing J-shaped hooks  30  while opposed end  24  has a pair of outwardly-facing J-shaped hooks. Construction of the retaining wall includes linking as many modules  12   b  as is necessary until the wall either ends or is angled. When angularity is required to the construction of the wall, a closed triangular-shaped module is added to end  24  of module  12   b  through gripping or securing engagement of outwardly-facing J-shaped hooks  26  with inwardly-facing J-shaped hooks. Completion of a modular retaining wall is effected by the attachment of module  12   c,  a module similar to  12   a  with the exception that the securing fingers are inwardly-projecting J-shaped hooks  30  in contrast to the outwardly-facing J-shaped hooks  26  of module  12   a.    
         [0040]     While the invention has been described in terms of open U-shaped modules and closed rectangular modules for the essentially linearly oriented modules, there is no need to limit the shape of the modules to such. In fact, as illustrated in  FIGS. 9-10 , both open and closed polygons are useful in the invention. As shown particularly in  FIG. 9 , end  12   a  or middle module  12   b  which was illustrated to be an open U-shaped three-sided polygon, may be envisioned as an open seven-sided polygon, wherein side panel  20  has been modified by inwardly-positioned side panels  20   a  and  20   b.  It is noteworthy that the apex of side panels  20   a  and  20   b  need not be equally spaced between bottom side  24  and end cap  36 , but may be positioned off-center. It is also noted that the length of side panels  20   a  and  20   b  need not be equal. In a similar manner, this concept may be extended to the closed polygons which were originally shown to be rectangular in shape in  FIG. 8 , but are illustrated to be polygonal in  FIG. 10 . This concept may equally be extended to the non-linearly oriented modules, e.g.,  14 .  
         [0041]     In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the Prior Art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described.  
         [0042]     This invention has been described in detail with reference to specific embodiments thereof, including the respective best modes for carrying out each embodiment. It shall be understood that these illustrations are by way of example and not by way of limitation.

Summary:
A modular retaining wall with improved features is illustrated and described. Open or closed polygonal modules having channels disposed therein are set at least partially below a surface, said surface either being land-based or aqueous-based, and interfaces therebetween, e.g., shoreline, and attached to each other by respective fastening means which provide engaging connectivity between the modules.