Abstract: A barrier device includes a first containment chamber and a second containment chamber. The first containment chamber is secured to the second containment chamber by a connector. A barrier wall includes a first barrier device having a first containment chamber, a second containment chamber, and a connector. A containment chamber of a second barrier device is positioned between the first containment chamber and the second containment chamber and is positioned in overlying relationship to the connector. A barrier wall is built by positioning a first barrier device, having a first containment chamber, a second containment chamber, and a connector on a support surface. A containment chamber of a second barrier device is positioned between the first containment chamber and the second containment chamber of the first barrier device and overlying the connector.

Abstract: A flexible interlocking element (10) having opposing, interlocking ends (12, 14). Element end (12), features a contour, including element top surface segment (16), extending to bend (18), then defining a tongue element (34) extending downwardly along an incline (19), to inverted bend (20), which defines a tongue side (60) having a tangent (62). The contour of the tongue, further extending downward and around to bend (22), which defines a tongue tip (58). The tongue tip (58) having a bottom (54) with a tangent (56). The tongue further extending upward along incline (26), then further extending horizontally to bend (28), then further extending vertically downward to bend (30). Bend (30) defines the lower edge of bottom surface segment (32). Element end (14) features a contour including element top surface segment (36) extending horizontally to bend (38).

Abstract: A protective wall assembly (8) for protecting an embankment (6) to prevent scouring of the embankment (6) during high water flows such as experienced in floods or tidal waves. The protective wall assembly (8) comprises a plurality of block assemblies (10) each having a body (11), a top surface (30), and a bottom surface (32). Each block assembly (10) further includes four side faces (34,34a,34b,34c) interconnected by four intermediate faces (13,13a,13b,13c) to define an eight-sided body. Each intermediate face (13,13a,13b,13c) has a bore (21,22) extending perpendicularly thereinto. A first connecting device (42) engages the bores (21,22) in a first pair of intermediate faces (13,13b) of a first pair of block assemblies (10A,10C). The length of one (21) of the bores (21,22) is different than a length of the other of the bores (21,22). The protective wall assembly (8) provides an environmentally friendly structure harmonized with the surrounding scenery.

Abstract: A method for reinforcing a slope in which field ground deformation characteristics of an unstable slope can be rapidly and reliably judged and the unstable slope recovered and restored to its own natural state by introduction and application of an earth reinforcement theory, where apparent cohesion is increased by reinforcement members.

Abstract: In an assembly of concrete revetments, each having two expansive surfaces, each having a first set of comparatively larger holes extending between the expansive surfaces, and each having a second set of comparatively smaller holes extending from at least some holes of the first set to outer edges of said revetment, wherein the revetments of an adjacent pair of the assembly are connected to each other by one or more bolts, each bolt has a flexible, polymeric shank, which has a proximal end and a distal end, a head attached to the proximal end, and a nut attachable to the distal end, and each bolt has its shank extending through a hole of the second set of each revetment of the adjacent pair.

Abstract: A weight strip constructed from a plurality of stacked sheets of elastomeric material slackly assembled for resting upon an uneven surface.

Abstract: A pouch (18), made of a water absorbent polymer that expands and becomes a gel in consistency upon absorbing water and that is biodegradable, is placed in each bag (10) of lesser volume. After the flood conditions have subsided, an opening (12) in each bag (10) is unsealed to drain the bags (10) of the biodegradable gel, as by squeezing the bag (10) to force the gel from the bag (10). The collapsed bags (10) are re-stored for future use and the gel is biodegraded as by disposition the conventional sewage system.

Abstract: A block having a semicircular male lobe and a semicircular female recess on opposing sides thereof. On other opposing sides of the block, there is formed a side edge shape such that when neighboring blocks are placed together, a circuitous water channel is formed between the blocks. The block includes cable channels formed therethrough, with the cable channels opening at the side edges into cable cavities. The cable cavities facilitate access to ends of the cables when the blocks are placed side by side.

Abstract: A storm water or flood water containment bag constructed of lightweight, inexpensive material with a quantity of absorbent material therein, for use in constructing dykes or dams to stop encroachment of water, or other liquid, the bag having an at least partially porous or permeable cover containing a liquid absorbing filler material composed of recycled carpet in a mixture of about 15 to 40% polypropylene, about 20 to 45% polyester, about 40 to 60% nylon, and about 5% or less of wool, rubber and/or fiber pad. The bag can be easily and quickly transported to a point of use and arranged to form a water barrier or wall.

Abstract: A synthetic hay bale and method are used to control water flow, soil erosion, and sediment flow at a construction site. The synthetic hay bale is made from a sheet member formed from ground carpet fibers that are packed together. The sheet member is rolled up to form a body member and the body member may be received within a mesh cover or may be strapped. A rod can be longitudinally inserted into the rolled up body member. The body member is secured to the ground by passing at least one stake through the body member or straddling the body member and inserting the stake into the ground.

Abstract: The invention relates to an element (10) comprised of a plurality of strips (12 to 26) which run in a horizontal and vertical manner and which have common points of intersection. The strips (12 to 26) are respectively closed rings (28), whereby each ring (28) alternately encloses the rings (28) or is guided through the rings (28) which are arranged at a right angle thereto. A forward end (36) of each ring (28) is guided through a rear end (38) of each ring (28) arranged at a right angle thereto. The ring projects over the lateral edges (40) of the ring (28) arranged at a right angle thereto in such a way that an eye (42) and/or loop is formed in order to accommodate an additional element and/or a connection element (34).

Abstract: Concrete blocks with an open cell structure extending throughout the block are assembled in substantially parallel columns and rows to from a mat structure capable of articulating over underwater structures. The blocks are assembled by flexible cables that pass through the center of each block through perpendicular apertures, which are located on different horizontal planes to prevent intersection of the cables. A removable abrasive resistant pad is placed on one surface of the blocks to prevent the concrete block from causing damage to the structure. The pad is comprised of a solid base with an opening matching the opening on the block. It also has a plurality of upwardly extending post which serve as a contact point between the pad and the underwater structure and at least one self-locking dowel extending downward, which are inserted into dowel holes on one surface of the block, after the concrete has hardened. The entire pad is one homogeneous material.

Abstract: For military as well as for civil applications there is provided a construction element comprising a disc-shaped central part (1) with at least four legs (2) extending outwards substantially radially with respect to a transversal axis (3) of the central part (1) and having longitudinal axes arranged in a plane perpendicular to the transversal axis (3) of the central part (1). The central part (1) has a face recess (4) extending inwardly from the central part (1) periphery between two adjacent legs (2). The face recess (4) has a width corresponding to the central part thickness and a depth being equal from one to two thirds of the central part width measured along an axis (8) of the face recess (4). The central part (1) is also furnished with a first passage (5) the axis (6) of which is parallel to the transversal axis (3) of the central part (1), and with a second passage (7), opening into the central part (1) face walls and having an axis (9) perpendicular to the axis (8) of the face recess (4).

Abstract: A cell confinement structure for confinement of material having a plurality of elongated plastic strips in a side by side relationship bonded together in spaced-apart, limited areas where the plurality of strips are capable of being stretched in width to form a unitary web of cells. The strips forming walls of the cells with at least one of the cell walls having a plurality of apertures in which each diameter is between about 3 mm and 17 mm. Preferably, each of the cell walls has a plurality of apertures with the total area of the apertures in the cell walls being between 19% and 28% of cell wall area.

Abstract: A cell confinement structure for confinement of material having a plurality of elongated plastic strips in a side by side relationship bonded together in spaced-apart, limited areas where the plurality of strips are capable of being stretched in width to form a unitary web of cells. The strips forming walls of the cells with at least one of the cell walls having a plurality of apertures in which each diameter is between about 3 mm and 17 mm. Preferably, each of the cell walls has a plurality of apertures with the total area of the apertures in the cell walls being between 19% and 28% of cell wall area. The sell structure may include tendons passing through the walls of the cell.

Abstract: An erosion control system for protecting a shoreline is provided comprising a first row of starter elements in contact with one another and fixedly attached to the shoreline; a second row of standard elements in contact with one another and matably engaged with the first row, such that the second row is closer to the shoreline and overlaps the first row in an interlocking manner; a third row of standard elements in contact with one another and matably engaged with the second row, such that the third row is closer to the shoreline and overlaps the second row; and wherein each successive row of standard elements is laterally offset from a previous row of standard elements.

Abstract: A system for preventing erosion and release of chemicals from exposed soil, the system including a pattern of horizontally-disposed, closely-spaced tires substantially filled and surrounded by inorganic fill material for limiting efflux of the exposed soil surface. In a first preferred embodiment, the system comprises the array of tires with an underlayment of open-weave lyophobic textile covering the soil surface. In a second preferred embodiment, the system comprises the array of tires with an underlayment of open-weave lyophobic textile and a fixated fill material for the individual tires with the top of the horizontally-disposed area of exposed fixated fill material containing a surface layer of water-soluble inorganic aggregate.

Abstract: A device for forming a siltation construction comprising a substantially rectangular cloth (1) of water-permeable material, which is anchored on all sides to a water bed by anchoring means. Floating elements (10) are arranged on cloth at a distance from one side (4) thereof and along the other sides (3) are formed pouches (1) open toward the center of the cloth.

Abstract: An elongate flexible container, made of a textile fabric and having at least one filling opening. The container is filled with solid material, such as sand or other ground material, for the formation of a body adapted for use as a core or base of a dam, a quay, a bank reinforcement, a jetty or a breakwater, or for filling holes or trenches, or for use at the bed of a waterway, or for the packaging and storage of contaminated material. The container is provided at its upper side with at least one filling opening. The container includes stitching extending in the longitudinal direction of the container and mutually connecting facing edges of the textile fabric.

Abstract: The method for engaging a geosynthetic or erosion mat including a soil engaging layer to underlying ground includes the steps of feeding a length of twine out over the soil engaging layer of the mat, and pressing a loop of the twine into the ground at intermittent points therealong. If required, an enhancing step of compressing the ground over the pressed in twine may be incorporated into the method.

Abstract: A turf product for use in erosion control is provided as a turf product matting of a fibrous material in combination with a reinforcing mesh for giving directional stability thereto. Turf is located above the matting and the reinforcing mesh with its root system passing thereinto. The turf is initially grown above the matting and the reinforcing mesh with its root mass passing therethrough onto an impervious surface. The impervious surface acts as a barrier to root transmission, so that the roots tend to mat above the impervious surface, and when the turf product is moved to its required location for use, the roots are then permitted to pass into an underlying surface.

Abstract: A block for use in a revetment system comprising a plurality of blocks arranged to form a mat. The block has a top surface, a bottom surface and first and second opposed side surfaces that extend between the top and bottom surfaces, and third and fourth opposed side surfaces extending between the top and bottom surfaces and the first and second side surfaces. The first and second opposing side surfaces have a mating recess and projection, such that a recess on a first side surface mates with a projection on a second side surface of an adjacent block in a revetment system. On each of the third and fourth sides is a channel and two interlocking tips disposed on either side of the channel. The interlocking tips of a third or fourth side of one block are adapted to fit into the channel of the third or fourth side of another block. The channel is configured so that there is the possibility of lateral movement when the blocks are configured into a mat.

Abstract: An improved geotextile container of the type for maintaining fill material includes a geotextile fabric configured into a tubular shape and having stitched, multi-layer, flanged seams with the stitched flange disposed inside the container. Due to this construction, outwardly directed forces imparted by the fill material will be directed against the stitching. An embodiment with an outer layer of geotextile material has an inner liner of geotextile material.

Abstract: A mat installation is disclosed which reduces shoreline deterioration due to wave and tide surging, comprising a series of concrete elements, disposed over a set of pipes fastened together, preferably in groups of three, by strapping or other suitable means and protected with a geotextitle fabric. The mat is then placed over the set of pipes and anchored at the onshore side of the pipes, with the pipes laterally facing the wave action.

Abstract: The erosion control system includes a plurality of erosion control blocks connected to one another by connectors to form an interconnected network of erosion control blocks conforming to the underlying terrain for erosion prevention. Each erosion control block includes a plurality of apertures therethrough each forming a side wall. The connector includes a pair of projecting legs for insertion into adjacent erosion control blocks. Each leg attachingly engages the side wall of the aperture of an erosion control block for connecting that erosion control block to an adjacent block. The legs include tapered extensions which frictionally engage the side wall, and in one embodiment of the erosion control block, the side wall includes a shoulder which engages the terminal end of the tapered extension. The erosion control block may have one end with convex arcuate surface and another end with a concave arcuate surface for providing an articulating joint between adjacent erosion control blocks.

Abstract: A hanging articulated mat assemblage disposed between pilings or on a support structure using a plurality of elements connected with flexible rope to each other and to a support beam which permits the mat to swing freely while supporting substantial weight, and optionally using a nonabrasive pad disposed on selected faces of the elements to prevent abrasion while swinging of the mat.

Abstract: The instant shoreline erosion-preventing bank installation comprises a vegetation supporting strengthened skin having negatively-buoyant bottom and side drop-skirts, which skirts each include an extendable reservoir of skin folded on itself accordion-like, and which skirts each include at least one weight. The side and bottom negatively-buoyant drop-skirts of the vegetation supporting strengthened skin fall as the bank is eroded by wave action, conforming the skin to the bank as it erodes in a storm, thereby preventing wash-away of the installation. Energy absorbing and flow control weighted ballasts are attached to the skin; which, among other things, control wave and wind action in a storm so as to prevent wash-off to, and erosion of, adjacent property that may be unprotected. In time, the installation of the invention is completely overgrown with vegetation, permitting the use and enjoyment of the bank protected thereby, provides long term protection from erosion and provides a wildlife habitat.

Abstract: The revetment mat comprises at least two webs joined together at aligned perimeter edges. Each web comprises a plurality of (a) interior blocks disposed side-by-side in rows and (b) a plurality of edge blocks defining a pair of perimeter edge rows of the web. The interior and edge blocks are interlinked together by threading a revetment cable through tunnels defined in the blocks. Each of the edge blocks defines a recess in one end thereof and further defines a pair of coaxial bores which extend from a first side to an interior face in the recess and from an opposing face in the recess to a second side of the edge block. An elongated rod is received in the bores and thereby extends across a gap in the recess between the opposing interior faces. A plurality of couplers are used to join a first web to a second web, which webs are positioned side-by-side. Each coupler is disposed within one of the recesses.

Abstract: A body having an interior with a plurality of chambers, a plurality of fracture zones and a plurality of filter zones which permit water to pass through opposing exterior surfaces of the body, in use the body interior being arranged to receive a substance which hardens on drying and fractures at locations defined by the fracture zones.

Abstract: A system used to insulate soil, most practically in waste sites and the like, including a plurality of geoinsulation blankets and an anchoring means. Each blanket has a flexible plastic casing sealed around its perimeter with at least one air vent through it, a resilient insulation batt contained within the casing, and attachment means of the hook and loop type positioned along its perimeter to adjoin overlapping edges of blankets in the system.

Abstract: An environmentally sound vegetation growth-enhancing erosion control blanket is formed from an elongated rectangular excelsior/wood wool mat. The mat is held together with adhesive and a surface pattern is embossed therein. When the finished blanket is placed atop the ground, the blanket serves to shield the earth area from wind and water erosion forces, without the presence of the plastic netting often used in the prior art. As the ground vegetation grows, it ultimately replaces the blanket which decomposes and furnishes the ground vegetation with a nutritive mulch.

Abstract: A ground stabilization structure having a plurality of rings secured together at peripherally adjoining surfaces by helical coil fasteners. The rings are arranged in a two dimensional array and the rings may be folded into a stack to provide for easy transportation of the structure. Preferably, the rings are tire beads cut from the rim of a waste tire and having a rigid wire support member embedded therein. The helical fasteners have a diameter sufficient to allow two rings to lie substantially flat on a ground surface with the peripheral surfaces of the rings contacting each other. The diameter of the coil also permits two adjacent secured rings to be folded upon each other to form a stack. A method of forming a ground stabilization structure is also provided in which the helical coils are threaded onto the rings at their peripheral junctions to form a two dimensional array.

Abstract: An environmentally sound vegetation growth-enhancing erosion control blanket is formed from an elongated rectangular excelsior/wood wool mat. The mat is held together with adhesive and a surface pattern is embossed therein. When the finished blanket is placed atop the ground, the blanket serves to shield the earth area from wind and water erosion forces, without the presence of the plastic netting often used in the prior art. As the ground vegetation grows, it ultimately replaces the blanket which decomposes and furnishes the ground vegetation with a nutritive mulch.

Abstract: A bag that self-closes from pressure of material insertable into the bag comprising (A) an openable overlapping elastic structure in which an innermost elastic material is disposed to completely cover an opening in the bag; and (B) an outermost elastic material disposed to completely overlap the innermost elastic material.

Abstract: Multiple sections of grid-like sheet material extend centrally through a thickness of a plurality of staggered rows of concrete panels to form a geomattress of unlimited dimensions. The sheet material preferably includes a plurality of parallel strands and perpendicular, intersecting bars. At least one bar extends within each concrete panel in a direction parallel to a longitudinal axis of the concrete panel to add strength to the formed geomattress and aid in lifting of the geomattress by the sheet material. The geomattress is formed by placing a section of sheet material above bottom mold halves filled with concrete and then filling top mold halves positioned above the sheet material with concrete. Gaps formed between adjacent rows of staggered panels and tapered sidewalls of the panels allow bending of the geomattress to aid in lifting the geomattress and to conform to a limited extent to the contour of the area onto which the geomattress is placed.

Abstract: A structure that prevents beach erosion and that builds-up the existing beach and shoreline is disclosed. The structure has a plurality of blocks that are configured into a matrix configuration. Each block has a pair of longitudinal rods extending from the block sides. The longitudinal rods have a hook at a first end and a loop at a second end. The blocks cooperate with each other so that the blocks become flexibly connected by placing the rod hook from a first block into the rod loop of a second and adjacent block. The process is repeated until a matrix is in place covering the area desired. Anchors are attached to the matrix assembly and buried in the sand to keep the matrix configuration in place at the assembly site.

Abstract: The invention relates to a groundcovering element, consisting of a plurality of components (1) with links (2,3) in between, a method for the manufacture thereof and a method for the manufacture of a mold (24, 25, 26, 27, 29, 30). According to the invention it is provided that the links between the components are deformable, possibly flexible and allow for a distance between adjacent components, resulting in a groundcovering element that is easy to lay, offers better possibilities of adjustment to various desired surfaces to be covered and is considerably more suitable for a more or less undulating terrain. In a method of manufacture, one steel mold part (34) cooperates with many rubber ones (31), so that with little investment a high production rate is obtained.

Abstract: Apparatus and method for constructing an artificial ocean reef for use below the ocean surface to serve as an offshore breakwater for inbound waves and thereby prevent beach erosion. The reef has a plurality of adjacent sections, each of which comprises an arched wall having a series of side-by-side transverse concrete blocks, and flexible interconnections between the blocks at adjacent lateral edges to provide a generally smooth outer surface. The arched wall sections are each formed above the water surface on a barge or the like and then submerged with a shoreward side having a shoreward end resting on the floor of the ocean and a seaward side with a seaward end resting on the floor of the ocean outwardly from the shoreward end to present the smooth outer surface on the seaward side of the wall to incoming waves. Adjacent sections are secured together to form a continuous barrier aligned with the shore line of the beach being protected.

Abstract: A system of concrete blocks is provided for use as a revetment for preventing soil erosion in which individual blocks are sized and shaped to be cable interconnected to form a matrix or mats. The matrix or mat or blocks overlies and holds in place a layer of porous and permeable geo-textile overlying the protected soil area. The shape of the individual blocks is such as to permit growth of vegetation therethrough and to channel water flowing over the surface of the blocks to increase the downward pressure on the geo-textile layer.

Abstract: A plant riprap material for use in a shoreline to prevent erosion, which plant riprap material comprises a felt material, a substrate within the felt material, a plurality of aquatic plants in the substrate, a geotextile material over the top of the felt material and a netting material to retain the plant riprap material in shape.

Abstract: In the case of concrete blocks having narrow through holes for water drainage (perforated blocks), in particular paving stones of various formats and sizes that can be laid on surfaces exposed to the rain, such as streets, paths, squares, parking areas and rings around planted trees, and can be filled by means of jointing means or by means of sand at the lateral ends, the problem exists that the holes become plugged upon jointing or sanding-in. In order to prevent this, the holes are closed at their top end until the jointing or sanding-in operation is complete. This is advantageously accomplished by means of a filling agent that can be floated away or dissolves by means of the addition of water.

Abstract: Mattress Gabions are provided for soil stabilization revetments, designed to halt erosion and/or to consolidate the soil. A protective revetment consisting of a structure of vegetable matter forms a mattress gabion which retains the soil inside each of a multiplicity of individual cells. Each cell of the container can be filled with earth or a soil or soil-forming mixture, encouraging the growth of vegetation inside the mattress, in order to afford a natural protection to the soil of banks or excarpments, etc. Once it has been filled, the mattress is closed by a top cover in double twist steel mesh, after laying a geosynthetic sheet between the two to keep in fine materials.

Abstract: Improved wood fiber mat comprised of a mixture of thermo-mechanically processed wood fibers and synthetic fibers.

Abstract: A ground anchor for use in securing above ground objects in place consists of a molded plastic body member having a cylindrical central portion with a cone-shaped projection terminating in a point at one end thereof and a concentrically disposed cylindrical stem projecting from the other end. The stem is of a smaller O.D. than that of the central portion and, thus, an annular shoulder surface is created at the junction. A tie plate is fitted into a slot formed in the molded plastic body. A cable or other tie member connects to that plate and to the object to be anchored. The anchor is driven into the ground by positioning a drive rod over the stem portion of the anchor body so that the end of that rod abuts the annular shoulder. Then, by hammering on the upper end of the drive rod, the anchor is driven into the ground to the desired depth. The anchor is configured so that tension on the tie cable tends to rotate the anchor within the earth to increase the resistance against pull-out.

Abstract: The present invention features a dual-purpose sediment mat for trapping loose sediments that have been disturbed upstream in a riverbed. The mat is generally rectangular in shape and laid horizontally on the riverbed. The low horizontal profile provides a mechanism by which the sediments can be entrapped without unduly disturbing the flow of the river. The sediment mat has a highly porous top surface and a tightly woven bottom surface to entrap the sediments settling thereupon. The mat itself is a loose arrangement of excelsior, straw or other sediment-absorbing material. Wooden stays define modular portions of the sediment mat, maintain its configuration and provide handles for moving the mat. Eyelets disposed at the corners and along the sides of the mat provide a mechanism for staking the mat to the riverbed. Thereafter, the sediment-rich mat can be anchored to the sides of the riverbank. There, it can be seeded to grow vegetation that beautifies and stabilizes the berm.

Abstract: A process and fabric for controlling soil erosion which comprises an erosion control mat formed of a scrim having a lightweight web secured thereto to be utilized by applying the erosion control mat to a soil surface. A method of producing such erosion control mat is also disclosed.

Abstract: A foldable cell structure is formed from water-permeable flexible strips whose width represents the height of the cells and which are connected to adjacent strips at intervals. An integral part of said cell structure is formed by strong stabilizing bands which, in the unfolded state of the cell structure, are arranged in straight lines and are at least predominantly parallel to one another, the cell structure preferably being formed by the unfolding of a water permeable sheet material provided with off-set, mutually parallel incisions of finite length. A further preferred embodiment of the cell structure has some of the water-permeable strips replaced or supplemented by stabilizing bands.

Abstract: A ground anchor comprises an anchor plate (1) which is to be driven edge first into the ground. A flexible anchor strap or web (4) is attached to the plate, and the plate has a tail flap (7) which provides a fulcrum about which the buried anchor plate can pivot. Apparatus (5) are provided on the anchor whereby it can be driven into the ground with rotation about a generally horizontal axis. Once it is buried the strap (4) can be used to increase the rotation of the plate and thus give the plate maximum resistance to withdrawal from the ground.

Abstract: Woven geotextile grid for earth reinforcement applications. The grid is formed of woven fabric which is coated with a suitable polyvinylchloride or other plastic coating. The fabric is formed of a plurality of spaced-apart pick yarn bundles which are interwoven with a plurality of spaced-apart warp yarn bundles. The pick yarn bundles are held in place in the warp yarn bundles with locking yarns which run parallel to the pick yarns and which are positioned adjacent to the edges of the pick yarn bundles. The warp yarns extend between the pick yarn bundles and locking yarns to lock the pick yarn bundles into place. A plurality of pairs of leno yarns oriented parallel to the warp yarns additionally strengthen the fabric by interlocking with one another in the spaces between pick yarn bundles and locking yarns. The result is a grid which has wide lateral and longitudinal members that lock together to form large interstices through which soil and water may penetrate.

Abstract: A revetment mattress for preventing the erosion of earthen structures comprising a revetment fabric having a pair of layers of flexible pervious plastic material interconnected by intermittent and staggered spacer threads. This structure has the ability to maintain the layers in a substantially parallel relationship once the mattress has been injected with filler material.