Patent Publication Number: US-6908258-B2

Title: Methods and apparatus for maintaining seawalls

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to the maintenance of seawalls disposed between bodies of water and retained earth and, more particularly, to methods and apparatus for maintaining seawalls using anchoring devices to strengthen the seawalls to resist potential damage and/or repair actual damage in the seawalls. 
   2. Discussion of the Related Art 
   Seawalls are commonly disposed between bodies of water and earth to provide physical boundaries between the bodies of water and the earth and to support or retain the earth by resisting the pressure of the retained earth against the seawalls. Seawalls can be used to separate earth from various types of bodies of water of various sizes and depths. Seawalls can be constructed in various ways and of various materials. Typically, seawalls have a vertical span or height sufficient for an upper end of the seawall to normally extend above the water with a lower end or toe portion of the seawall embedded in the earthen floor to extend below the body of water. The distance that a seawall extends above the water may vary depending on the height of the retained earth above the water and/or anticipated fluctuations in water level. The depth to which the embedded toe portion extends below the water may vary in accordance with the vertical span of the seawall and/or the depth of the body of water to provide sufficient support for the seawall to resist movement from the pressure of the retained earth against the seawall. Accordingly, seawalls are usually designed for a particular depth body of water. The thickness of seawalls may vary depending on site-specific loads and other engineering parameters. One representative type of seawall comprises concrete panels about ten to fifteen feet high, about four feet wide and about three to five inches thick disposed in side by side abutment to form a continuous wall. 
   Since the earth exerts greater pressure against seawalls than the water, seawalls are oftentimes damaged or destabilized during their lifetimes as evidenced, for example, by movement, displacement, shifting, cracking and/or misalignment of the seawalls. Sometimes seawalls are placed at risk for damage or instability due to a change in conditions occurring subsequent to installation of the seawalls. For instance, if a body of water is dredged resulting in a greater depth body of water and a lesser depth of penetration for the toe portion of an existing seawall, the lesser depth of penetration for the toe portion may no longer be sufficient for the seawall to support the pressure of the retained earth such that the seawall is susceptible to damage or instability. In some cases, the height of the retained earth on the earth facing side of an existing seawall may be increased, causing increased pressure of retained earth against the seawall by which the seawall may be damaged or destabilized. In addition to the pressures of retained earth, seawalls may be damaged or destabilized directly or indirectly due to other conditions including collisions or other impacts, corrosion, environmental factors, and age. Since removal and replacement of damaged and/or unstable seawalls involves significant cost and disruption, it is preferable to strengthen existing seawalls to repair and/or avoid damage or instability. 
   It has been proposed to strengthen seawalls to resist movement using anchors or tie rods in conjunction with cementitious material as represented by U.S. Pat. No. 1,270,659 to Ravier, U.S. Pat. No. 4,480,945 to Schnabel, Jr., U.S. Pat. No. 4,711,604, to Heimsoth et al., and U.S. Pat. No. 4,728,225 to Brandl et al. U.S. Pat. No. 3,371,494 to Lagerstrom, U.S. Pat. No. 4,253,781 to Fischer et al., and U.S. Pat. No. 4,911,582 to Pierce, Jr. et al. disclose the use of anchors or tie rods in conjunction with cementitious material to restrain structural walls other than seawalls. Helical anchors for building constructions are represented by U.S. Pat. No. 4,499,698 to Hoyt et al., U.S. Pat. No. 5,011,366 to Hamilton, et al., U.S. Pat. No. 5,120,163 to Holdeman et al., U.S. Pat. No. 5,139,368 and U.S. Pat. No. 5,171,107 to Hamilton et al., U.S. Pat. No. 5,213,448 to Seider et al., and U.S. Pat. No. 5,927,905 to van Halteren. 
   Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls have various disadvantages including complicated structure and installation steps, major disruption, the need for excavating and/or disturbing the earth, partial or complete demolition of existing walls, the need to temporarily hold back or contain water during installation, the need to install additional and/or replacement wall structure, the use of cementitious material to assist in anchoring, the need for backfill, and the inability to execute installation from a body of water. Prior apparatus and methods which require earth-side access are untenable where homes or other buildings are situated close to seawalls making it undesirable and even prohibitive to disturb the earth on the earth facing sides of the seawalls and/or to conduct seawall maintenance from the earth facing sides. Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls using anchors or tie rods generally lack the ability to rigidly interconnect a plurality of spaced anchors or tie rods installed in a wall to maintain the spacing between the anchors or tie rods in a desired direction. Furthermore, prior apparatus and methods for repairing and/or maintaining seawalls and other retaining walls using anchors or tie rods do not allow a plurality of spaced anchors or tie rods installed in a wall to be adjustably interconnected to adjust the spacing between the anchors or tie rods. Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls do not contemplate closing openings in the walls by adjustably moving the walls between interconnected anchors or tie rods installed in the walls on opposite sides of the openings. 
   Accordingly, there is a need for apparatus and methods for maintaining seawalls by repairing and/or strengthening the seawalls utilizing anchoring devices having anchoring members installed from the water facing sides of the seawalls to extend through the seawalls into the retained earth and retaining members secured to the anchoring members along the water facing sides of the seawalls without the need for excavation and/or disturbance of the earth, removal of existing seawalls or seawall portions and/or the installation of additional seawalls or seawall portions, and without the need for backfill, cementitious material and water containment while having simplified structure and installation steps. There is also a need for apparatus and methods for maintaining seawalls by which at least a pair of spaced anchoring members extending through a seawall may be rigidly secured in interconnected relation to maintain the spacing between the interconnected anchoring members. Another need exists for apparatus and methods for maintaining seawalls by which at least a pair of spaced anchoring members extending through a seawall may be adjustably interconnected to adjust the spacing between the interconnected anchoring members. A need further exists for apparatus and methods for maintaining seawalls by which anchoring members installed in a seawall on opposite sides of an opening in the seawall may be interconnectedly drawn toward one another to close the opening. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to overcome the aforementioned disadvantages of prior apparatus and methods for maintaining seawalls. 
   Another object of the present invention is to strengthen a seawall utilizing one or more anchoring devices each including an anchoring member having a shaft installed to extend through the seawall from a water facing side thereof and an anchor anchored in earth on an earth facing side of the seawall, and a retaining member secured on the shaft along the water facing side of the seawall. 
   It is also an object of the present invention to restrain a seawall against movement due to pressure of retained earth on an earth facing side of the seawall by compressing the seawall between a retaining member secured on a shaft of an anchoring member extending through the seawall and an anchor of the anchoring member embedded in the retained earth. 
   The present invention has as an additional object to adjustably compress a seawall between an anchor of an anchoring member embedded in retained earth on an earth facing side of the seawall and a retaining member disposed along a water facing side of the seawall by adjustably securing the retaining member along a shaft of the anchoring member carrying the anchor and extending through the seawall at a selected non-perpendicular angle. 
   It is a further object of the present invention to tension an anchoring member longitudinally between an anchor of the anchoring member embedded in retained earth on an earth facing side of a seawall and a retaining member adjustably secured in a selected longitudinal portion along the length of a shaft of the anchoring member extending from the anchor through the seawall at an acute angle with the seawall. 
   Moreover, it is an object of the present invention to rigidly interconnect at least a pair of anchoring members extending through a seawall at spaced locations to fix the separation distance between the anchoring members. 
   Yet another object of the present invention is to rigidly interconnect a first anchoring member extending through a seawall to more than one other anchoring members extending through the seawall at spaced locations from the first anchoring member to fix the separation distances between the first anchoring member and the more than one other anchoring members. 
   It is an additional object of the present invention to adjustably interconnect at least a pair of anchoring members extending through a seawall at spaced locations to adjust the separation distance between the anchoring members and maintain the adjusted separation distance. 
   The present invention has as a further object to adjustably interconnect a first anchoring member extending through a seawall to more than one other anchoring members extending through the seawall at spaced locations from the first anchoring member to adjust the separation distances between the first anchoring member and the more than one other anchoring members and maintain the adjusted separation distances. 
   Additionally, it is an object of the present invention to interconnectedly secure a plurality of anchoring members extending through a seawall at spaced locations to one another via connecting members secured on the anchoring members along a water facing side of the seawall. 
   Another object of the present invention is to close an opening in a seawall by compressing the seawall between anchoring members extending through the seawall on opposite sides of the opening. 
   Yet a further object of the present invention is to compress a seawall with a desired compressive force between anchoring members extending through the seawall at laterally spaced locations. 
   The aforesaid objects are achieved individually and in combination, and it is not intended that the present invention be construed as requiring two or more of the objects to be combined unless expressly required by the claims attached hereto. 
   Some of the advantages of the present invention are that the anchoring devices are installed from the water facing sides of seawalls without the need for excavating or disturbing the earth, removing existing seawalls or seawall portions, adding additional seawalls or seawall portions, water containment, and backfill; the anchoring devices are installed using procedures conducted from the body of water such that the earth facing sides of the seawalls need not be interfered with; the need for cementitious material is eliminated; the anchors can have various configurations including helical formations, arm formations and/or expandable/collapsible formations; any type of earth anchor can be used on the anchoring members; the apparatus and methods of the present invention can be employed on various types of seawalls made of various materials and having various dimensions; the apparatus and methods of the present invention may be used for various aspects of seawall maintenance including the repair of damaged seawalls and as a preventative to avoid damage to existing seawalls not already damaged; the apparatus and methods of the present invention may be used to repair or avoid various types of actual or potential damage to seawalls including movement, shifting or displacement of seawalls, cracked or separated seawalls and misalignment of seawall panels; the apparatus and methods of the present invention may be used for various stages of disrepair in seawalls; depending on the extent of deviation from original specifications, a seawall may be restored to original specifications with a single adjustment performed upon installation of one or more anchoring devices or with multiple incremental adjustments performed dynamically over time following installation of one or more anchoring devices; the apparatus and methods of the present invention may be implemented in accordance with site-specific conditions and engineering requirements; the apparatus and methods of the present invention are particularly advantageous for use where earth-side access is restricted or not viable and/or where replacement of a seawall would entail negative consequences; installation of the anchoring devices may be accomplished using conventional machinery and tools; the number of and locations for the anchoring members installed in a seawall may vary in accordance with individual requirements; the anchoring members may be interlocked in various lateral directions including vertical, horizontal and/or any other angular lateral direction on the seawalls; pairs of anchoring members may be forcefully drawn toward one another in various lateral directions including vertical, horizontal and/or any other angular lateral direction on the seawalls; the shafts of the anchoring members extend through passages formed through the seawalls to facilitate installation; where the cross-sectional sizes of the passages are larger than the cross-sectional sizes of the shafts therethrough, the excess cross-sectional area of the passages not occupied by the shafts may be filled in various ways; ferrules or other structural members may be disposed on the shafts and introduced in the passages with an interference fit to fill the excess cross-sectional area not occupied by the shafts, to support the shafts in the passages and/or to center the shafts in the passages; the retaining members can be designed in various ways for securement on the shafts parallel or non-parallel to the water facing sides of the seawalls; various types of securing members may be used to secure the retaining members on the shafts of the anchoring members; the retaining members may have abutment surfaces configured to abut the water facing sides of the seawalls; various inserts can be inserted or interposed between the retaining members and the water facing sides of the seawalls; the retaining members distribute forces or pressures on the seawalls; the anchoring members can be interlocked by interlocking the retaining members therefor; the retaining members of any two anchoring members can be rigidly interlocked using a fixed length connecting member having opposing ends secured to the retaining members of the two anchoring members, respectively; the retaining members of any two anchoring members can be adjustably interlocked using an adjustable length connecting member having opposing ends secured to the retaining members of the two anchoring members, respectively; the apparatus and methods of the present invention can be used to strengthen existing seawalls for which the depth of penetration of the toe portions is reduced, such as following deepening of the bodies of water on the water facing sides of the seawalls; and the apparatus and methods of the present invention can be used to strengthen existing seawalls for which the height of retained earth is increased on the earth facing sides of the seawalls. 
   These and other objects, advantages and benefits are realized with the present invention as generally characterized in an apparatus for maintaining a seawall disposed between a body of water and retained earth, the apparatus comprising at least two anchoring devices for being installed on the seawall at spaced locations and a connecting member for rigidly interconnecting the anchoring devices to fix or maintain the separation distance between the anchoring devices. The apparatus may comprise first and second anchoring devices or any number of anchoring devices. Each anchoring device includes an anchoring member and a retaining member. Each anchoring member may comprise a longitudinally extending shaft carrying an anchor having a configuration to anchor the anchoring member in the retained earth. The anchor may comprise any type of earth anchor having various anchor formations including a helical formation, an arm formation and/or a collapsible expandable formation. Each retaining member may comprise a flange having a bore hole therethrough for receiving an end of the shaft of the corresponding anchoring member by which the retaining member is movable longitudinally along the shaft. Each retaining member may have an abutment surface for abutment with a water facing side of the seawall, and the retaining members and the abutment surfaces may have various configurations. Any of the anchoring devices may further include an insert for being interposed between the retaining member and the water facing side of the seawall. Any of the anchoring devices may further comprise a filler for being disposed around the shaft of the anchoring device to fill the passage in the seawall through which the shaft extends when the anchoring device is installed on the seawall. Each retaining member may be secured on the corresponding shaft in various ways using one or more securing structures formed separately from or as part of the retaining member. Securing structures formed separately from the retaining member may comprise a securing member of the anchoring device, and the securing member may include a nut for threadedly engaging the end of the shaft extending from the bore hole of the retaining member. Securing structure formed as part of the retaining member may include a thread along the bore hole for threadedly engaging the end of the shaft. 
   Each anchoring member is inserted in a passage formed through the seawall and is advanced in the passage into the retained earth to anchor the anchor in the retained earth a distance spaced from an earth facing side of the seawall. The end of each anchoring member extends from the passage along the water facing side of the seawall, and the retaining member is secured on the end of the anchoring member extending from the passage. The retaining members apply compressive force against the seawall by virtue of the seawall and retained earth being compressed between the retaining members and the anchors and by virtue of the anchoring members being tensioned between the retaining members and the anchors. The connecting member rigidly interconnects the ends of the anchoring members to fix or maintain the separation distance between the anchoring members, and the connecting members may be attached to the retaining members of the anchoring devices. The length of the connecting member between the interconnected anchoring members or devices may be fixed or may be adjustable to permit the separation distance between the anchoring members or devices to be selectively adjusted. 
   The present invention is also generally characterized in a method of maintaining a seawall disposed between a body of water and retained earth involving the steps of forming a passage through the seawall to extend downwardly at an acute angle from a water facing side of the seawall to an earth facing side of the seawall, inserting an anchoring member through the passage from the water facing side and into the retained earth on the earth facing side, advancing the anchoring member into the retained earth to anchor an anchor of the anchoring member in the retained earth at a distance spaced from the earth facing side of the seawall with a longitudinally extending shaft of the anchoring member which carries the anchor extending through the passage along the water facing side of the seawall, and securing a retaining member on an end of the shaft extending from the passage on the water facing side of the seawall to apply compressive force against the water facing side of the seawall to resist displacement of the seawall due to pressure of the retained earth. The method may be performed entirely from a vessel deployed on the body of water without the need for excavation or disturbance of the earth or for earth-side access. Any number of anchoring devices may be installed on the seawall so that the compressive force applied to the seawall is sufficient to strengthen the seawall to resist displacement without the need for cementitious materials for anchoring. The passage may be formed in the seawall by drilling, for example, using a directional drilling machine or any other suitable machinery deployed on the body of water. Advancement of the anchoring member into the retained earth may involve moving the anchoring member into the retained earth longitudinally and/or rotationally. Securing the retaining member on the end of the shaft may involve rotating a securing member on the shaft into compressive engagement with the retaining member with the shaft extending through a bore hole of the retaining member. The method may involve interposing an insert between the retaining member and the water facing side of the seawall. The method may further involve filling the passage around the shaft extending therethrough. Advancement of the anchoring member into the retained earth may involve advancing the anchoring member with the anchor in a collapsed position and moving the anchor from the collapsed position to an expanded position to anchor the anchoring member in the retained earth. The method may comprise periodically adjusting the compressive force of the retaining member against the seawall. 
   The present invention is further generally characterized in a method of maintaining a seawall disposed between a body of water and retained earth involving installing a first anchoring member on the seawall at a first location, installing a second anchoring member on the seawall at a second location, spaced from the first location, and rigidly interconnecting the anchoring members to maintain the separation distance between the anchoring members. The anchoring members may be installed to extend through the thickness of the seawall with an anchor of each anchoring member anchored in the retained earth at a distance spaced from an earth facing side of the seawall and with an end of each anchoring member extending from a water facing side of the seawall. Installation of the anchoring members may involve securing first and second retaining members on the ends of the first and second anchoring members, respectively, and the first and second anchoring members may be rigidly interconnected by rigidly interconnecting the first and second retaining members. Securement of the retaining members on the anchoring members may involve compressing the seawall and retained earth between the retaining members and the anchors, and the method may involve periodically adjusting the compressive force of the retaining members against the seawall. Rigidly interconnecting the first and second anchoring members may involve adjusting the separation distance between the first and second anchoring members. The method may involve installing the first anchoring member on one side of an opening in the seawall, installing the second anchoring member on an opposite side of the opening, with the step of rigidly interconnecting the first and second anchoring members including drawing the first and second anchoring members toward one another to adjust the separation distance between the anchoring members an amount sufficient to close the opening and maintaining the adjusted separation distance between the first and second anchoring members after the opening is closed. The method may be used to close openings formed by separated cracks or seams in the seawall. The method may involve drawing a pair of interconnected anchoring members together in various directions including vertical and horizontal directions. The method may involve periodically adjusting the separation distance between the anchoring members. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates an anchoring device and method according to the present invention. 
       FIG. 2  is a broken, exploded side view of the anchoring device of FIG.  1 . 
       FIG. 3  is a broken side view depicting an alternative anchoring device and method according to the present invention. 
       FIG. 4  is a broken, exploded side view of the alternative anchoring device of FIG.  3 . 
       FIG. 5  is a broken plan view of a seawall depicting one arrangement for a plurality of anchoring devices installed thereon. 
       FIG. 6  is a broken plan view of a seawall depicting a plurality of further alternative anchoring devices installed thereon in rigid interconnected relation. 
       FIG. 7  is a broken plan view of a seawall having openings therein and depicting additional alternative anchoring devices installed thereon in pairs on opposite sides of the openings in adjustable interconnected relation. 
       FIG. 8  is a broken plan view of the seawall of  FIG. 7  depicting the interconnected pairs of additional alternative anchoring devices drawn toward one another to close the openings. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 5  illustrate a seawall  10  installed in use between a body of water  12  and retained earth  14 . Seawall  10  comprises a plurality of seawall panels  16  in side by side abutment. Panels  16  are depicted as being planar with each panel having a height or span in the vertical direction, a width in the horizontal direction and a thickness perpendicular to the height and width. The width of each panel  16  extends between side edges of the panel, and the side edges of adjacent panels  16  may be in abutment as shown in  FIG. 5  to form a continuous seawall  10 . The seawall  10  has an upper end, which may be finished with a cap  18 , normally extending above the water  12 , a lower end or toe portion  20  penetrating the earthen floor  22  to extend below the water  12 , a water facing side  24  and an earth facing side  26 . The distance that the upper portion extends above water  12  will usually depend on the height of retained earth  14  above water  12  and/or anticipated fluctuations in the level of water  12 , for example due to tides and/or storms. The toe portion  20  is typically driven into the earthen floor  22  during installation of seawall  10 , and the distance the toe portion extends below the water  12  is typically selected in accordance with the depth of body of water  12 , the height of retained earth  14  and/or other site-specific conditions to support the seawall in an upright vertical orientation to resist the pressure of retained earth  14 . 
   In one representative seawall, the panels  16  are made of concrete and have a height of about ten to fifteen feet, a width of about four feet and a thickness of about three to five inches. The seawall  10  can be constructed in various alternative ways including, for example, as bulkheads, pilings and/or piers, and of various materials including, for example, steel, wood and concrete. The seawall  10  can have various dimensions. Body of water  12  may be any type of body of water including, for example, oceans, harbors, channels, sounds, rivers and lakes. The retained earth  14  may comprise one or more constituents including, for example, dirt, sand, rock and shells. One representative composition for retained earth  14  is an aggregate of sand and shell. Site-specific conditions may be determined using standard engineering tests and/or calculations, such as soil analysis, from which the force or pressure on seawall  10  from earth  14  can be determined. 
   The force or pressure exerted on seawall  10  by retained earth  14  is ordinarily greater than the force exerted on seawall  10  by body of water  12  such that the seawall may become damaged or unstable. Damage or instability of seawall  10  may be evidenced by movement, displacement or shifting of seawall  10  from its upright vertical orientation, by openings in the seawall due to cracks in individual seawall panels  16  or separation of adjacent seawall panels  16 , and/or by misalignment of seawall panels or cracked portions of panels. Various other conditions may contribute to or cause damage or instability in seawall  10  including collisions or other impacts with the seawall, corrosion and age. Where body of water  12  is deepened after construction of seawall  10 , the increased depth of body of water  12  results in a reduced penetration depth for toe portion  20  below earthen floor  22  as shown by dotted line  22  in FIG.  1 . Consequently, the seawall  10  may no longer be able to support or retain the retained earth  14  and may be increasingly susceptible to damage or instability. If the height of retained earth  14  is increased as shown by dotted line  14  in  FIG. 1 , the increased pressure of retained earth exerted on seawall  10  may place the seawall at increased risk of damage or instability. In accordance with the present invention, seawall  10  is maintained by installing one or more anchoring devices to strengthen and repair the seawall where there is actual damage or instability in the seawall and/or to strengthen the seawall to resist potential damage or instability in the seawall from the pressure of earth  14  or other causes. Accordingly, maintenance of a seawall in accordance with the present invention is intended to encompass repair and/or strengthening of a seawall in cases of actual or potential damage or instability arising from the pressure of retained earth and/or other causes. 
   An anchoring device  32  according to the present invention is illustrated in  FIGS. 1 and 2  and comprises an anchoring member  34  and a retaining member  36 . Anchoring member  34  includes an elongate shaft  38  having a forward end  40 , a rearward end  42  and at least one anchor  44  carried on shaft  38 . The shaft  38  is longitudinally straight and has a central longitudinal axis. The shaft may have various uniform or non-uniform cross-sections to extend through a passage formed in seawall  10  as explained further below. 
   Shaft  38  is depicted with a circular cross-section that is uniform or constant along the length of the shaft; however, the cross-section of the shaft can be non-uniform or non-constant along its length. The anchor  44  may be carried on shaft  38  close to or along forward end  40  as shown in  FIGS. 1 and 2 , but may be disposed at various locations along the length of the shaft. The anchor  44  can have various configurations to anchor the anchoring member  34  in earth  14  and resist withdrawal of the anchoring member from the earth, and any type of earth anchor can be used for anchor  44 . The anchor  44  is depicted as comprising a helical formation of sufficient external diameter to anchor the anchoring member  34  in earth  14  and resist withdrawal of the anchoring member from the earth. The helical formation  46  facilitates advancement of the anchoring member  34  in earth  14  via rotation and forward longitudinal movement of the anchoring member. The forward end  40  may terminate at a taper, point or other configuration to facilitate advancement of the anchoring member  34  in earth  14  as described further below. The rearward end  42  may be provided with engagement structure for engagement with securing structure of the anchoring device as described further below. The engagement structure may be designed in various ways, and the engagement structure is depicted by way of example as a thread  50  along the rearward end  42  of the shaft  38 . The anchoring member  34  may be made of various materials enabling the anchoring member to sustain preselected torque, compression and tensile forces. Representative materials include galvanized steel and stainless steel. 
   The retaining member  36  may be designed in various ways to be secured on the rearward end  42  of shaft  38  via securing structure formed separately from or as part of the retaining member. The retaining member  36  includes a flange  52  having a forward abutment surface  54  and a bore hole  56  extending through the flange at an angle to the abutment surface. The flange  52  is depicted as being planar with planar abutment surface  54  for abutment with the planar water facing side  24  of seawall  10 . It should be appreciated, however, that the abutment surface and/or the flange can have various non-planar configurations and can have various perimetrical configurations including a square perimetrical configuration as shown in FIG.  5 . The bore hole  56  may be centrally or non-centrally located in flange  52  and has a central longitudinal axis  58  disposed at an angle A with the abutment surface  54  as shown in FIG.  2 . The bore hole  56  has a cross-sectional configuration and size to receive the rearward end  42  of shaft  38  concentrically therethrough with a close fit. As an example of securing structure formed as part of the retaining member, the retaining member  36  can include securing structure  62  engageable with the engagement structure of shaft  38  to secure the retaining member  36  on the shaft  38  in a desired longitudinal position along the length of the shaft  38 . The securing structure formed as part of the retaining member  36  can be designed in various ways and may comprise an internal thread along bore hole  56  threadedly engageable with the external thread  50  of shaft  38 . As an example of securing structure formed separately from the retaining member  36 , the anchoring device  32  may comprise a securing member  62 ′, such as a nut, having an internal thread along a hole therethrough for threadedly engaging the external thread  50  of shaft  38  and having an external size preventing passage of the securing member through the bore hole  56  of the retaining member. For ease of installation and adjustment, the securing member  62 ′ may be preferable to the securing structure  62 , in which case the retaining member  36  can be provided without securing structure  62 . When retaining member  36  is disposed on shaft  38  with the shaft  38  extending through bore hole  56 , the central longitudinal axis  58  of bore hole  56  and shaft  38  is disposed at angle A with the plane P of abutment surface  54  as shown in FIG.  1 . As explained further below, angle A is an acute angle which corresponds to an acute angle selected for the central longitudinal axis of shaft  38  with the water facing side  24  of seawall  10  when the shaft  38  extends angularly downwardly through the thickness of the seawall  10  from the water facing side  24  to the earth facing side  26 . As shown in  FIG. 2 , the central longitudinal axis of the hole through the securing member  62 ′ may be coaxial with axis  58  so that the hole through the securing member is disposed at angle A to a forward face of the securing member  62 ′. The retaining member  36  and securing member  62 ′ may be made of any suitable materials including galvanized and stainless steels. 
   A method for maintaining seawall  10  using anchoring device  32  is performed from body of water  12  without the need for excavating or disturbing retained earth  14  or earthen floor  22  and without the need for earth-side access to seawall  10 . As shown in  FIG. 1 , the method can be conducted from a vessel  64 , which may be a conventional spud barge having a platform  66  which floats upon the body of water  12  and spuds  68  (only one of which is shown) selectively extendable for lowering from platform  66  into the earthen floor  22  whereby the platform  66  is maintained at a location relative to the water facing side  24  of seawall  10  suitable to conduct the seawall maintenance. The vessel  64  may be towed to the selected location by a tugboat, and the vessel serves as a workstation for equipment, materials and personnel. The spuds  68  may be raised using winches. A directional drilling or boring machine or any other suitable machinery  70  is supported on vessel  64  and includes a drive shaft  72  that is rotatable as well as being movable forwardly and rearwardly in a longitudinal or axial direction for the drive shaft as shown by arrows in FIG.  1 . The drive shaft  72  is capable of being positioned at various angles to the seawall  10 . A drill bit  74  is carried by a forward end of drive shaft  72  and may be removably coupled or connected to the forward end of drive shaft  72  in any suitable manner. Various couplings or connectors may be provided for removably coupling or connecting the drive shaft  72  to the anchoring member  34  in coaxial relation or alignment, and the drive shaft  72  may also be removably coupleable or connectable with the retaining member  36  using suitable couplings or connectors. Additional machinery and/or tools may be carried by barge  66  as needed to conduct seawall maintenance pursuant to the present invention. The directional drilling machine  70  also includes suitable instruments or gauges for measuring tension, compression and torque. 
   In accordance with the method of the present invention, the drive shaft  72  carrying drill bit  74  is positioned at the preselected angle A to the seawall  10 , and the drive shaft  72  is rotatably driven while being advanced or moved forwardly in a longitudinal or axial direction to form a passage  76  extending entirely through the thickness of seawall  10  from the water facing side  24  to the earth facing side  26  as shown in FIG.  1 . The passage  76  has a cross-sectional size to accommodate the anchoring member  34  extending therethrough and, accordingly, a drill bit  74  of appropriate size is selected for formation of the passage  76 . The drive shaft  72  is retracted or moved rearwardly in the longitudinal or axial direction for withdrawal from the seawall  10  upon completion of the passage  76 . Operation of the machine  70  to control rotation and axial or longitudinal advancement and retraction of the drive shaft  72  may be effected by an operator situated on the vessel  64 . A central longitudinal axis of the passage  76  is disposed at angle A with the water facing side  24  of the seawall  10  and extends downwardly from the water facing side  24  to the earth facing side  26 . The angle A, the cross-sectional size of the passage  76  and the type and size of anchoring member  34  are predetermined or preselected in accordance with site-specific conditions, engineering tests and/or calculations. 
   Once the passage  76  has been formed in seawall  10 , the drive shaft  72  is coupled or connected with the shaft  38  of anchoring member  34  in coaxial relation or alignment. Coupling or connection of the drive shaft  72  with the shaft  38  may be performed above the water on or from the vessel  64 . The drive shaft  72  having the anchoring member  34  coupled or connected thereto is positioned at angle A to seawall  10 , and the drive shaft  72  is again advanced in a longitudinal or axial direction to introduce the anchoring member  34 , forward end  40  first, into and through the passage  76  from the water facing side  24  to the earth facing side  26  of the seawall  10 . The drive shaft  72  is rotated while continuing to be advanced in the longitudinal or axial direction to rotate and advance the anchoring member  34  into the retained earth  14  while the rearward end  42  of the shaft  38  extends from the passage  76  along the water facing side  24  of the seawall  10 . The configuration of forward end  40  and anchor  44  of anchoring member  34  facilitate advancement of the anchoring member in earth  14 . As it is advanced, the anchoring member  34  contacts the retained earth  14  such that the anchoring member penetrates the retained earth. Accordingly, the portion of the anchoring member  34  extending into the retained earth from the earth facing side of the seawall is embedded in the retained earth  14  without any gap or space between the anchoring member and the surrounding earth. The anchoring member  34  is advanced a preselected or predetermined distance into earth  14  such that anchor  44  is anchored and embedded in earth  14  at a preselected or predetermined distance from the earth facing side  26  of seawall  10 . The configuration of anchor  44  embedded in earth  14  resists withdrawal of the anchoring member  34  from the earth  14 . The shaft  38  of anchoring member  34  extends through the passage  76 , and the eternally threaded rearward end  42  of shaft  38  extends from the passage  46  on the water facing side  24  of seawall  10 . As shown in  FIG. 1 , the rearward end of shaft  38  may extend from the passage  76  into the body of water  12 . 
   Where the seawall  10  is made of a material capable of being cut or penetrated by anchor  44  being driven through passage  76 , the cross-sectional size of passage  76  may be made no larger than necessary to accommodate the cross-section of shaft  38  extending therethrough. However, the cross-sectional size of passage  76  may be made larger than necessary to accommodate the cross-section of shaft  38 , and may be made large enough to accommodate the cross-section of anchor  44 . As described below, anchors may be used which have collapsed positions presenting a relatively small or narrow cross-section and expanded positions presenting a relatively large or wide cross-section as described below, and the passage  76  may be made no larger than necessary to accommodate the cross-section of the anchor in the collapsed position. Where an annular or other gap is presented in passage  76  around shaft  38  due to the cross-sectional size of the passage being larger than the cross-section of the shaft  38  extending therethrough, this gap can be filled with any suitable filler as explained further below. Accordingly, the anchoring device  32  may further comprise a filler, such as the sleeve  153  described below and as shown in FIG.  5 . 
   The retaining member  36  is secured on the rearward end  42  of shaft  38  along the water facing side  24  of seawall  10  with a predetermined torque to obtain a predetermined tension in anchoring member  34  and a predetermined compression against seawall  10  in an anchored position for the anchoring member. The rearward end  42  of shaft  38  is inserted in the borehole  56  of retaining member  36  with the abutment surface  54  of the retaining member facing the water facing side  24  of seawall  10 . Where the retaining member  36  is provided with securing structure  62 , the retaining member  36  is rotated relative to the shaft  38  in a first rotational direction with the thread  50  on the rearward end  42  in threaded engagement with the thread of borehole  56 . Rotation of the retaining member  36  relative to the shaft  38  in the first rotational direction causes forward advancement of the retaining member  36  longitudinally along the shaft  38  toward seawall  10 . The retaining member  36  is rotated relative to the shaft  38  in the first rotational direction to a predetermined torque with the abutment surface  54  in abutment with the water facing side  24  of seawall  10  to obtain a predetermined tension in anchoring member  34  and a predetermined compression against seawall  10 . The retaining member  36  is secured on the shaft  38  in the longitudinal position corresponding to the predetermined torque, compression and tension due to engagement of thread  50  with the securing structure  62 . 
   Where the anchoring device  32  comprises securing member  62 ′, the rearward end  42  of shaft  38  is inserted in the bore hole  56 , which may be provided without the internal thread, with the abutment surface  54  facing the water facing side  24 . The retaining member  36  is advanced along the shaft  38  in the direction of the seawall, and the end of shaft  38  extending rearwardly from the bore hole  56  is inserted in the hole of securing member  62 ′ to threadedly engage the internal thread of the securing member  62 ′ with the external thread  50  of shaft  38 . The securing member  62 ′ is rotated in a first rotational direction to advance the securing member  62 ′ forwardly along shaft  38  into compressive engagement with the retaining member  36 . The securing member  62 ′ is rotated to a predetermined torque with the abutment surface of the retaining member  36  applying a predetermined compression against seawall  10 . The securing member  62 ′ and the retaining member  36  are secured on shaft  38  in longitudinal positions corresponding to the predetermined torque, compression and tension, the securing member  62 ′ being held in place due to engagement of its thread with the thread of shaft  38 . 
   When the anchoring device  32  is installed on seawall  10 , the seawall  10  and earth  14  between the retaining member  36  and anchor  44  are compressed, and the anchoring member  34  is tensioned between retaining member  36  and anchor  44  to strengthen seawall  10  to resist displacement of the seawall in the direction of water  12 . The predetermined torque, compression and tension are selected in accordance with site-specific conditions, the type and/or size of anchoring member, and engineering specifications. Since the central longitudinal axis of bore hole  56  and shaft  38  are disposed at angle A to the abutment surface  54 , the abutment surface  54  is in face to face abutment or contact with the water facing side  24  of seawall  10  along plane P, with the central longitudinal axis of shaft  38  extending downwardly from the water facing side  24  to the earth facing side  26 . 
   The retaining member  36  can be secured on the rearward end  42  of shaft  38  at various positions along the length of rearward end  42 . Where the retaining member  36  is provided with securing structure  62 , the torque, compression and tension can be increased by further rotating the retaining member  36  relative to the shaft  38  in the first rotational direction, and the torque, compression and tension can be decreased by rotating the retaining member  36  relative to shaft  38  in a second rotational direction, opposite the first rotational direction, to cause retraction or rearward movement of the retaining member  36  longitudinally along the shaft  38  in a direction away from seawall  10 . When the securing member  62 ′ is used to secure the retaining member  36 , the torque, compression and tension can be increased by further rotating the securing member  62 ′ in the first rotational direction, and the torque, compression and tension can be decreased by rotating the securing member  62 ′ in a second rotational direction, opposite the first rotational direction, to cause retraction or rearward movement of the securing member  62 ′ longitudinally along the shaft  38  in the direction away from seawall  10 . Accordingly, torque, compression and tension adjustments are possible in the anchoring devices. The retaining member  36  and securing member  62 ′ could be rotated, advanced and retracted via drive shaft  72  using an appropriate connector or coupling to releasably couple or connect the retaining member  36  and/or securing member  62 ′ to the drive shaft  72 . The retaining member  36  and securing member  62 ′ can be secured on the anchoring member  34  using any other suitable machinery or tools operated and controlled from the vessel  64 . 
     FIG. 1  depicts anchoring device  32  as a first anchoring device installed on seawall  10  at a first location and depicts drive shaft  72  in the process of drilling another passage  76  through seawall  10  for installation of another or second anchoring device to be installed on seawall  10  at a second location spaced laterally above the first anchoring device  32 . In  FIG. 1 , a portion of rearward end  42  protrudes from the securing member  62 ′ on the water facing side  24  of seawall  10 . If desired, this portion can be cut or trimmed following installation of anchoring device  32 . However, it may be advantageous to allow this portion to remain intact to facilitate torque, compression and/or tension adjustments of anchoring device  32  conducted following installation. Following installation, the anchoring device  32  can be periodically checked or inspected, and the torque, compression and/or tension can be increased or otherwise adjusted as needed to strengthen seawall  10 . 
   Where seawall  10  is not already damaged or unstable, one or more anchoring devices  32  may be installed on seawall  10  to strengthen the seawall to resist potential damage or instability. The compressive force applied by the one or more anchoring devices  32  against seawall  10  via the intermediary of earth  14  enables the seawall  10  to resist deviation from original design specifications, such as displacement from its upright vertical orientation. Where seawall  10  has already deviated from its original design specifications and experienced actual damage or instability, such as displacement from its upright vertical orientation, the one or more anchoring devices  32  can be used to strengthen the seawall and repair the actual deviation or damage. As an example, dotted lines in  FIG. 1  depict seawall  10  displaced from its upright vertical orientation in the direction of water  12  due to the pressure of earth  14 . Depending on the amount of displacement of seawall  10  from its original design specifications, sufficient compressive force may be applied against the seawall  10  by the installation of one or more anchoring devices to repair the seawall by moving it to the upright vertical orientation and to strengthen the seawall by resisting displacement from the upright vertical orientation. Accordingly, a seawall that has deviated from its original design specifications may be restored to its original design specifications upon the installation of one or more anchoring devices. More commonly, incremental adjustments made to the one or more anchoring devices over time will be needed to restore a deviated seawall to its original design specifications. One or more anchoring devices  32  can be installed on seawall  10  to repair various types or stages of damage in seawall  10 . Where a plurality of anchoring devices  32  are installed on seawall  10 , the angle A for the anchoring devices may be the same as or different from each other. Paint, epoxy and/or urethane may be applied to exposed surfaces following installation of one or more anchoring devices for added strength, protection and/or cosmetic enhancement. 
     FIGS. 3 and 4  depict an alternative anchoring device  132 , the anchoring device  132  being shown in  FIG. 3  installed on a seawall  10 . Anchoring device  132  comprises anchoring member  134 , retaining member  136  and filler  151 . Anchoring member  134  is similar to anchoring member  34  except that anchor  144  for anchoring member  134  has an arm formation including a plurality of arms  147  and has a collapsible/expandable formation. Arms  147  have ends pivotally mounted to shaft  138  at a pivot location  149  such that the arms  147  are pivotable relative to the shaft  138  about the pivot location. The arms  147  extend angularly outwardly from the shaft  138  in the rearward direction in an expanded position for anchor  144  shown in FIG.  3  and in solid lines in FIG.  4 . In the expanded position, the anchor  144  presents a configuration to resist withdrawal of the anchoring member  134  from earth  14  and, in the expanded position for anchor  144 , the anchor presents a relatively large or wide cross-sectional profile. The arms  147  are disposed alongside shaft  138  in a collapsed position for anchor  144  shown in dotted lines in  FIG. 4  such that anchor  144  presents a configuration facilitating insertion and advancement of anchoring member  134  through the seawall  10  and into earth  14  during installation. In the collapsed position, anchor  144  presents a relatively small or narrow cross-sectional profile. The anchor  144  is disposed in the collapsed position while the anchoring member  134  is being passed through the seawall  10  and advanced in the earth  14 , and the anchor  144  is moved to the expanded position to be embedded in the earth  14  upon the anchoring member  134  being advanced the appropriate distance. Various mechanical mechanisms can be provided for selectively moving the anchor  144  between the collapsed and expanded positions and/or for locking the anchor  144  in the expanded position. The retaining member  136  is similar to retaining member  36  except that the borehole  156  through flange  152  of retaining member  136  is perpendicular to abutment surface  154 . The borehole  156  may be threaded for engagement with the thread of shaft  138  or may be without a thread. The anchoring device  132  may include a securing member  162 ′ for securing the retaining member  136  on shaft  138  when the borehole  156  is without a thread. The securing member  162 ′ is similar to securing member  162  except that the threaded hole through securing member  162 ′ is perpendicular to the forward face of the securing member  162 ′. 
   The filler  151  comprises a cylindrical ferrule or sleeve  153  having a lumen  155  extending axially therethrough. The lumen  155  has a cross-sectional diameter or size corresponding to the external cross-sectional diameter or size of the rearward end  142  of shaft  138  to receive the shaft  138  therethrough with a close fit. The sleeve  153  has an external diameter or cross-sectional size corresponding to the diameter or cross-sectional size of passage  76  formed in seawall  10  such that the sleeve  153  can be disposed in passage  76  with an interference fit. The sleeve  153  could be provided with engagement structure along lumen  155  for engaging the engagement structure of shaft  138 , and such engagement structure may comprise a thread  159  for threaded engagement with the thread  150  on the rearward end of shaft  138 . 
   Installation of anchoring device  132  on seawall  10  in a method of maintaining seawall  10  is similar to that described above for anchoring device  32 . A passage  76  of appropriate size is formed through the thickness of seawall  10  at a selected angle for insertion of anchor  144  and shaft  138  therethrough with the anchor  144  maintained in the collapsed position. The anchoring member  134  is advanced into the retained earth  14  the appropriate distance and anchor  144  is moved from the collapsed position to the expanded position whereby the anchor  144  is embedded in the retained earth  14  to resist withdrawal of anchoring member  134 . The filler  151  is used to fill the annular gap present in passage  76  around the shaft  138  extending therethrough. Accordingly, the sleeve  153  is positioned on the rearward end  142  of shaft  138  which extends from the water facing side  24  of seawall  10  as accomplished by inserting the rearward end  142  in the lumen  155 . The sleeve  153  is advanced longitudinally along the shaft  138  in the direction of seawall  10  so that the sleeve enters passage  76  with an interference fit and thereby fills the gap around shaft  138 . The sleeve  153  also supports and centers the shaft  138  in the passage  76 . Where the sleeve  153  is provided with thread  159 , the sleeve is advanced by being rotated relative to the shaft  138  in a first rotational direction. The longitudinal position of the sleeve  153  along the shaft  138  may be maintained due to threaded engagement of thread  150  with thread  159 . The drive shaft  72  of machine  70  or any other suitable machinery and/or tools can be used to position and advance the sleeve  153  on the shaft  138  from vessel  64 . The sleeve  153  may be retracted or moved rearwardly along the shaft  138  for longitudinal adjustment and, where the sleeve is provided with thread  159 , it may be rotated on shaft  138  in a second rotational direction, opposite the first rotational direction, to cause longitudinal rearward movement of the sleeve along the shaft  138  in a direction away from seawall  10 . The sleeve  153  may be made of any suitable material including galvanized and stainless steels. Although filler  151  is depicted as a definitive structural component, it should be appreciated that the filler may comprise any suitable filler material with or without a definitive structural shape. 
   The retaining member  136  is secured on the portion of rearward end  142  which protrudes from sleeve  153  and the passage  76  on the water facing side of seawall  10  and is used to establish tension in anchoring member  134  and compression against seawall  10  as described above for retaining member  36 . Tension in anchoring member  134  and compression against seawall  10  may be established using securing member  162 ′ as described for securing member  62 ′. Since the bore hole  156  of retaining member  136  is perpendicular to planar abutment surface  154 , the abutment surface  154  is at an angle to the water facing side  24  of seawall  10  due to the downward angle of passage  76 . Accordingly, the abutment surface  154  is not in face to face abutment with the water facing side  24 , and there is a space presented between the abutment surface  154  and the water facing side  24 . As shown in  FIG. 3 , the anchoring device  132  further comprises an insert  161  for being disposed in the space between the abutment surface  154  and the water facing side  24  to transmit force against the seawall  10  from retaining member  136 . Insert  161  may have any geometric configuration needed to distribute the force of retaining member  136  against the water facing side  24 . In the case of anchoring device  132 , the insert  161  has a wedge shaped configuration for being disposed in the angular space presented between abutment surface  154  and water facing side  24  with an abutment surface  163  of the insert facing the water facing side  24 . During installation, the retaining member  136  is advanced along shaft  138  with the insert  161  interposed between abutment surface  154  and water facing side  24 . The retaining member  136  is advanced along shaft  138  into abutment with the insert  161 , which in turn abuts the water facing side  24  via abutment surface  163  and applies compressive force against the seawall as explained above for retaining member  36 . 
   Anchoring device  32  thusly is representative of an anchoring device in which the abutment surface of the anchoring device in contact with the water facing side of the seawall is formed in its entirety by the abutment surface of the retaining member. Anchoring device  132  is representative of an anchoring device in which the abutment surface of the anchoring device in contact with the water facing side of the seawall is formed in part by the abutment surface of the retaining member and in part by an abutment surface of an insert interposed between the retaining member and the water facing side. It should be appreciated that in the anchoring device  132 , the abutment surface  154  of retaining member  136  itself can be designed with a configuration  154 ′ corresponding to the configuration resulting from the combination of abutment surfaces  154  and  163  as shown in  FIG. 4  so that insert  161  may be eliminated. Accordingly, the abutment surfaces of the anchoring devices which apply force against the seawall may be formed partly or entirely by the abutment surfaces of the retaining members and may be formed partly or entirely by the abutment surfaces of the inserts. The insert  161  can be designed in various ways as one or more parts or materials and may comprise various shoring or shim members. 
     FIG. 5  illustrates one of many possible arrangements for one or more anchoring devices installed on seawall  10 .  FIG. 5  depicts a plurality of adjacent seawall panels  16   a ,  16   b  and  16   c  each having one or more anchoring devices installed thereon. Although one or more anchoring devices will typically be installed on each seawall panel, any number of seawall panels  16  which form the seawall  10  can have any number of anchoring devices installed thereon, and some panels may be without anchoring devices. Panel  16   a  has anchoring devices  32   a  and  32   b  installed thereon at first and second spaced locations, respectively, on panel  16   a  laterally spaced from and aligned with each other in the vertical direction. Panel  16   b  is adjacent panel  16   a  and has anchoring devices  32   c  and  32   d  installed thereon, anchoring device  32   c  being depicted without the securing member  62 ′ in order to show sleeve  153 . Anchoring devices  32   c  and  32   d  are installed at first and second spaced locations, respectively, on panel  16   b  laterally spaced from and aligned with each other in the vertical direction. In addition, the first and second locations for anchoring devices  32   c  and  32   d  are laterally spaced from and aligned with the first and second locations for anchoring devices  32   a  and  32   b , respectively, in the horizontal direction. Panel  16   c  is adjacent panel  16   b  and has one anchoring device  32   e  installed thereon at a location laterally spaced from the first and second locations for anchoring devices  32   c  and  32   d . The location for anchoring device  32   e  is not aligned in the horizontal direction with the first and second locations for anchoring devices  32   c  and  32   d  but, rather, is staggered or offset with respect thereto in the horizontal direction. Anchoring device  32   c  is depicted in dotted lines as including a sleeve  153  as described above.  FIG. 5  shows an arrangement where all of the anchoring devices are disposed below water  12 ; however, it should be appreciated that any or all of the anchoring devices could be disposed above the water depending on site-specific conditions. 
     FIG. 6  depicts an apparatus for maintaining a seawall comprising a plurality of alternative anchoring devices, at least one connecting member for interconnecting a pair of the alternative anchoring devices and one or more fasteners for connecting the at least one connecting member to the pair of anchoring devices which are to be interconnected. The apparatus of  FIG. 6  comprises first, second and third anchoring devices  232   a ,  232   b  and  232   c  each comprising an anchoring member  234  and a retaining member  236  as shown for anchoring device  232   a . Each anchoring member  232   a ,  232   b  and  232   c  is also shown as comprising a securing member  262 ′. The anchoring members  234  may be similar to anchoring members  34  or  134  and include shafts  238  as shown for anchoring device  232   a . The retaining members  236  may be similar to retaining members  36  or  136  except that each retaining member  236  includes one or more legs  265  extending therefrom. Each retaining member  236  may comprise a flange  252  of square peripheral configuration defined by four straight sides, with there being a leg  265  extending perpendicularly from each side in a direction radial to the bore hole of the flange which receives shaft  238 . Each leg  265  has a hole  267  therethrough for receiving a fastener. The securing member  262 ′ may be similar to securing members  62 ′ or  162 ′. The apparatus of  FIG. 6  comprises first and second connecting members  271   a  and  271   b  each comprising a straight, longitudinally extending channel member  273  having first and second opposing ends. A longitudinal slot  278  is formed in each of the first and second ends, the slots  278  being aligned with one another in the longitudinal direction for the channel member. Each slot  278  has a closed inner end and a closed outer end. The channel members  273  are rigid members of fixed predetermined length with a predetermined longitudinal distance between the outer ends of slots  278 . The channel members  273  may be made of any suitable material including galvanized and stainless steels. Four fasteners are provided in the apparatus of  FIG. 6 , each comprising a threaded bolt  269  and a nut (nut shown) threadedly engageable on the bolt  269 . 
   In a method of seawall maintenance using the apparatus of  FIG. 6 , the anchoring devices  232   a ,  232   b  and  232   c  may be installed on a seawall  10  with the anchoring member of each anchoring device placed in its anchored position in a manner similar to that described above for anchoring devices  32  and  132 .  FIG. 6  illustrates first and second anchoring devices  232   a  and  232   b  installed on panel  16   a  of seawall  10  and third anchoring device  232   c  installed on panel  16   b  of seawall  10 . The first and second anchoring devices  232   a  and  232   b  are installed at laterally spaced first and second locations on seawall  10  on opposite sides of a crack  283  in panel  16   a  which has not yet separated or opened. Since the crack  283  extends in the horizontal direction, the first and second anchoring devices  232   a  and  232   b  are laterally spaced from and aligned with one another in the vertical lateral direction traversing crack  283 . The retaining members  236  for anchoring devices  232   a  and  232   b  are positioned so that a leg  265  of first anchoring device  232   a  is aligned with a leg  265  of second anchoring device  232   b  in the vertical lateral direction traversing crack  283 , and the aligned legs  265  of the first and second anchoring devices  232   a  and  232   b  extend toward each other from their respective flanges  252 . Anchoring device  232   c  is installed on panel  16   b  of seawall  10  at a third location on seawall  10  laterally spaced from and aligned in the horizontal lateral direction with the first location for anchoring device  232   a . The first anchoring device  232   a  and the third anchoring device  232   c  are installed on opposite sides of a vertically extending seam  284  defined between the side edges of adjacent panels  16   a  and  16   b , and the seam  284  has not yet separated or opened. The retaining members  236  for anchoring devices  232   a  and  232   c  are positioned so that a leg  265  of first anchoring device  232   a  is aligned with a leg  265  of third anchoring device  232   c  in the horizontal lateral direction traversing seam  284 . The aligned legs  265  of the first and third anchoring devices  232   a  and  232   c  extend toward each other from their respective flanges  252 . 
   Following installation of the first and second anchoring devices  232   a  and  232   b  with their anchoring members in their anchored positions, the method of seawall maintenance utilizing the apparatus of  FIG. 6  involves rigidly interconnecting the anchoring members  234  of the first and second anchoring devices  232   a  and  232   b  to fix or maintain the separation distance between the anchoring members of the first and second anchoring devices in the vertical lateral direction and rigidly interconnecting the anchoring members  234  of the first and third anchoring devices  232   a  and  232   c  to fix or maintain the separation distance between the anchoring members of the first and third anchoring devices in the horizontal lateral direction. The first connecting member  271   a  is rigidly interconnected to the anchoring members  234  of the first and second anchoring devices  232   a  and  232   b  by aligning the outer ends of slots  278  of the first connecting member  271  a with the holes  267  in aligned legs  265  of the first and second anchoring devices, respectively. Bolt  269  is inserted through each pair of aligned outer ends and holes  267  and are secured in place via nuts, respectively. If desired, the holes  267  in the legs  265  of the anchoring devices may be threaded to threadedly engage the bolts. The first end of the first connecting member  271   a  is adjacent or in abutment with the retaining member  236  of first anchoring device  232   a  and the second end of the first connecting member  271   a  is adjacent or in abutment with the retaining member  236  of second anchoring device  232   b . Accordingly, the first and second anchoring devices  232   a  and  232   b  are prevented from moving inwardly toward one another in the vertical lateral direction. The anchoring devices  232   a  and  232   b  are prevented from moving outwardly away from one another in the vertical lateral direction due to engagement of bolts  269  with the closed outer ends of the slots  278  of the first connecting member  271   a . Since the anchoring devices  232   a  and  232   b  are not rigidly interconnected until after installation with their anchoring members in their anchored positions, the tension and compression established with each anchoring device is independent of the tension and compression established in the other. 
   Following installation of the first anchoring device  232   a  and the third anchoring device  232   c  with their anchoring members in their anchored positions, the second connecting member  271   b  is rigidly interconnected to the anchoring members  234  of the first and third anchoring devices by aligning the outer ends of slots  278  of the second connecting member  271   b  with the holes  267  in the aligned legs  265  of the first and third anchoring devices, respectively. Bolts  269  are inserted through each pair of aligned outer ends and holes  267  in the aligned legs  265  of the first and third anchoring devices and are secured in place via nuts, respectively. The first end of the second connecting member  271   b  is adjacent or in abutment with the retaining member  236  of the first anchoring device  232   a  and the second end of the second connecting member  271   b  is adjacent or in abutment with the retaining member  236  of the third anchoring device  232   c  to prevent movement of the first and third anchoring devices toward one another in the horizontal lateral direction. Movement of the first and third anchoring devices  232   a  and  232   c  away from one another in the horizontal lateral direction is also prevented due to engagement of bolts  269  with the closed outer ends of slots  278  of the second connecting member  271   b . Again, the tension and compression established with anchoring device  232   a  is independent of that established with anchoring device  232   c  since the anchoring devices are not rigidly interconnected until after the anchoring devices have been installed. 
   Due to the rigid interlocking connection between the first and second anchoring devices  232   a  and  232   b , separation, misalignment or other displacement of crack  283  is prevented. Due to the rigid interlocking connection between the first and third anchoring devices  232   a  and  232   c , separation, misalignment or other displacement of seam  284  is prevented. It should be appreciated that the legs  265  can extend from the retaining members  236  in any desired lateral direction to fix or maintain a desired separation distance between a pair of interconnected anchoring devices in any desired lateral direction. Any suitable machinery and/or tools can be used to secure the connecting members to the anchoring devices in interconnected relation from vessel  64 . The anchoring devices  232   a ,  232   b  and  232   c  can be inspected or checked periodically and torque, compression and tension adjustments can be made along with adjustments to the fasterners, as needed. 
   A further alternative apparatus for seawall maintenance is shown in  FIGS. 7 and 8  and is similar to the apparatus depicted in  FIG. 6  except for the number of anchoring devices and connecting members and except for the connecting members of the apparatus of  FIGS. 7 and 8  having an adjustable length. The apparatus of  FIGS. 7 and 8  comprises first, second, third and fourth anchoring devices  332   a ,  332   b ,  332   c  and  332   d  which are similar to the anchoring devices  232   a ,  232   b  and  232   c . The apparatus of  FIGS. 7 and 8  comprises first, second and third connecting members  371   a ,  371   b  and  371   c , each comprising a turnbuckle or other adjustment mechanism. As shown for connecting member  371   a , each connecting member  371   a ,  371   b  and  371   c  comprises an actuator or housing  385  having opposed ends, respectively, threadedly receiving the stems of adjustment members  387  terminating at eye formations at opposed first and second ends of the connecting member. The housing  385  is rigid and has a straight longitudinally extending configuration mounting straight stems extending longitudinally from the opposed ends of the housing  385  in longitudinal alignment with one another but in opposite directions. The housing  385  may be cylindrical or any suitable configuration. The adjustment members  387  are rigid with the eye formations being in line with the stems thereof. The stems and, therefore, the adjustment members  387 , are longitudinally extendable from the housing  385  when the housing is rotated in a first rotational direction relative to the adjustment members  387  while being longitudinally retractable in the housing  385  when the housing is rotated relative to the adjustment members  387  in a second rotational direction, opposite the first rotational direction, as shown by arrows in FIG.  7 . The apparatus depicted in  FIGS. 7 and 8  includes fasteners for connecting the first and second ends of each connecting member with a pair of anchoring devices, and the fasteners may each comprise a bolt  369  and nut (not shown) similar to the fasteners of the apparatus of FIG.  6 . 
   In a method of seawall maintenance using the apparatus of  FIGS. 7 and 8 , the anchoring devices  332   a ,  332   b ,  332   c  and  332   d  may be installed on a seawall  10  in a manner similar to that described above for anchoring devices  232   a ,  232   b  and  232   c .  FIG. 7  illustrates first and second anchoring devices  332   a  and  332   b  installed on panel  16   a  of seawall  10  and third and fourth anchoring devices  332   c  and  332   d  installed on adjacent panel  16   b  of seawall  10 . The first and second anchoring devices  332   a  and  332   b  are installed at laterally spaced first and second locations on seawall  10  on opposite sides of a horizontally extending crack  383  in seawall panel  16   a  which has separated or opened to present an opening between upper and lower portions of panel  16   a . Since the crack  383  extends in the horizontal direction, the first and second anchoring devices  332   a  and  332   b  are laterally spaced from and aligned with one another in the vertical lateral direction traversing the crack  383 . The retaining members  336  for anchoring devices  332   a  and  332   b  are positioned so that a leg  365  of first anchoring device  332   a  is aligned with a leg  365  of second anchoring device  332   b  in the vertical lateral direction traversing crack  383 . The aligned legs  365  of the first and second anchoring devices  332   a  and  332   b  extend toward each other from the flanges of their respective retaining members  336 . 
   Anchoring device  332   c  is installed on panel  16   b  of seawall  10  at a third location on seawall  10  laterally spaced from and aligned in the horizontal lateral direction with the first location for anchoring device  332   a . First anchoring device  332   a  and third anchoring device  332   c  are installed on opposite sides of a vertically extending seam  384  defined between the side edges of adjacent panels  16   a  and  16   b , and the seam  384  has separated or opened to present an opening between the panels  16   a  and  16   b . The retaining members  336  for anchoring devices  332   a  and  332   c  are positioned so that a leg  365  of first anchoring device  332   a  is aligned with a leg  365  of a third anchoring device  332   c  in the horizontal lateral direction traversing seam  384 . The aligned legs  365  of the first and third anchoring devices extend toward each other from the flanges of their respective retaining members  336 . Anchoring device  332   d  is installed on panel  16   b  at a fourth location on seawall  10  laterally spaced from and aligned in the horizontal lateral direction with the second location for anchoring device  332   b . The second anchoring device  332   b  and the fourth anchoring device  332   d  are installed on opposite sides of the seam  384 . The retaining members  336  for anchoring devices  332   b  and  332   d  are positioned so that a leg  365  of second anchoring device  332   b  is aligned with a leg  365  of fourth anchoring device  332   d  in the horizontal lateral direction traversing seam  384 . The aligned legs  365  of the second and fourth anchoring devices  332   b  and  332   d  extend toward each other from the flanges of their respective retaining members  336 . The third and fourth anchoring devices  332   c  and  332   d  are in vertical alignment with one another on seawall panel  16   b.    
   A method of seawall maintenance utilizing the apparatus of  FIGS. 7 and 8  further involves adjustably rigidly interconnecting the anchoring members of the first and second anchoring devices  332   a  and  332   b , adjustably rigidly interconnecting the anchoring members of the first and third anchoring devices  332   a  and  332   c , and adjustably rigidly interconnecting the anchoring members of the second and fourth anchoring devices  332   b  and  332   d . Following installation of the first and second anchoring devices  332   a  and  332   b , the first connecting member  371   a  is interconnected to the anchoring members of the first and second anchoring devices by aligning the eye formations of the first connecting member with the holes in the aligned legs of the first and second anchoring devices. A bolt  369  is inserted through each pair of aligned eye formations and holes and the bolts are respectively secured with nuts. With the first and second ends of the first connecting member  371   a  thusly secured to the aligned legs  365  of the first and second anchoring devices  332   a  and  332   b , the housing  385  of the first connecting member  371   a  is rotated in the first rotational direction to retract the adjustment members  387  thereof into the housing whereby the anchoring members of the first and second anchoring devices are moved or drawn toward one another in the vertical lateral direction as shown by arrows in FIG.  8 . The adjustment members  387  of the first connecting member  371   a  are retracted into the housing  385  an amount sufficient to draw the anchoring members of the first and second anchoring devices  332   a  and  332   b  together a distance sufficient to move the upper and lower portions of panel  16   a  toward one another to close or reduce the size of the opening of crack  383  as shown in FIG.  8 . Once the first and second anchoring devices  332   a  and  332   b  have been drawn together to close or reduce the size of crack  383  with a desired compressive force, the separation distance between the first and second anchoring members  3321  and  332   b  in the vertical lateral direction is fixedly maintained by the first connecting member  371   a  due to threaded engagement of the stems of the adjustment members  387  and the housing  385 . 
   Following installation of the first anchoring device  332   a  and the third anchoring device  332   c , the second connecting member  371   b  is interconnected to the anchoring members of the first and third anchoring devices  332   a  and  332   c  by aligning the eye formations of the second connecting member  371   b  with the holes in the aligned legs  365  of the first and third anchoring devices and securing the eye formations to the aligned legs  365  using bolts  369  and nuts as described for the first connecting member  371   a . The housing  385  for the second connecting member  371   b  is rotated in the first rotational direction to retract the stems of the second connecting member into the housing thereby moving or drawing the anchoring members of the first and third anchoring devices  332   a  and  332   c  toward one another in the horizontal lateral direction to correspondingly draw panels  16   a  and  16   b  toward one another to close or reduce the size of the opening of seam  384  as shown in FIG.  8 . Once the opening of seam  384  has been closed or reduced in size with a desired compressive force, the longitudinal separation distance between the anchoring members of the first and third anchoring devices  332   a  and  332   c  in the horizontal lateral direction is fixedly maintained by the second connecting member  371   b . The anchoring members of the second and fourth anchoring devices  332   b  and  332   d  are drawn together using third connecting member  371   c  to close or reduce the size of the opening of seam  384  and thereafter maintain a fixed separation distance between the anchoring members of the second and fourth anchoring devices as described for the second connecting member  371   b  and the first and third anchoring devices  332   a  and  332   c . The second and fourth anchoring devices can be drawn together simultaneously, sequentially or in alternating increments with the first and third anchoring devices. Since the stems are extendable from the housings  385 , the separation distance between interconnected pairs of anchoring devices can be adjusted. Accordingly, the connecting members  371   a ,  371   b  and  371   c  can be used to separate seawall panels or seawall panel portions by moving seawall panels or seawall panel portions away from one another by rotating the housing  385  in the second rotational direction. Various machinery and/or tools can be used to secure the connecting members  371   a ,  371   b  and  371   c  to the anchoring devices and to effect actuation of the adjustment members  387  via rotation of the housing  385  from the vessel  64 . Depending on the size of the opening in the seawall, the opening may be completely closed with one adjustment of interconnected anchoring members. More commonly, an opening will be closed incrementally over time with periodic adjustments of interconnected anchoring members 
   With the methods of the present invention, compressive force may be applied against a seawall by one or more anchoring devices sufficient to prevent displacement of the seawall without the need for cementitious material to assist in anchoring. The methods of the present invention can be conducted entirely from a vessel located on the body of water without the need for excavation or disturbance of the earth, earth-side access to the seawall or underwater diving. The methods can be used to strengthen various types of seawalls to resist potential damage and to correct various types and stages of actual damage. The anchors can have various configurations to anchor the anchoring members in the retained earth, and the retaining members can have various configurations. The retaining members can be secured on the anchoring members in various ways including the use of securing members threaded onto the ends of the anchoring members. Where a gap is presented around the anchoring member in the passage through the seawall, various types of fillers can be used to fill the gap. The fillers can include structural components or filler materials not having a definitive structural shape. The retaining members may comprise flanges having various planar or non-planar configurations, and the abutment surfaces of the retaining members can have various configurations. The anchoring devices may include various inserts insertable between the retaining members and the water facing side of the seawall. The retaining members distribute force or pressure against the seawall to resist displacement thereof. Any number of anchoring devices can be installed in a seawall at various locations and in various arrangements. Any pair of anchoring devices can be rigidly interconnected to maintain a fixed separation distance between the anchoring devices. Any pair of anchoring devices may be interconnected using a connecting member which permits adjustment of the separation distance between the interconnected anchoring devices. Adjustable connecting members may be provided which permit the separation distance between interconnected anchoring devices to be increased and/or decreased. Anchoring devices can be installed on relatively movable portions of a seawall and adjustably interconnected to effect movement of the relatively movable portions and thereafter maintain the adjusted position of the relatively movable portions. Adjustably interconnected anchoring devices can be used to close various types of openings in seawalls including openings between seawall panel portions and between seawall panels. Adjustably interconnected anchoring devices can also be used to separate relatively movable portions of a seawall including relatively movable panels or panel portions. The type of anchoring device or devices utilized and the torque, compression and tension for the anchoring device or devices may be selected in accordance with site-specific conditions and engineering specifications. Following initial installation, the anchoring devices and apparatus of the present invention can be checked or inspected periodically and adjustments may be made as needed to maintain or obtain a desired torque, compression and/or tension. Deviations from original design specifications can be corrected in seawalls using the anchoring devices to apply the necessary corrective forces. A deviation from original design specifications can be corrected at one time in a single application of corrective force or forces using one or more devices, or may be corrected dynamically or incrementally over a period of time in multiple applications of corrective force or forces using one or more anchoring devices, much in the manner of orthodontia. 
   Inasmuch as the present invention is subject to many variations, modifications and changes in detail, it is intended that all subject matter discussed above or shown in the accompanying drawings be interpreted as illustrative only and not be taken in a limiting sense.