US20100278594A1

US20100278594A1 - Erosion control system

Info

Publication number: US20100278594A1
Application number: US12/433,022
Authority: US
Inventors: Terence Sheridan
Original assignee: GeoStorage Corp
Current assignee: GeoStorage Corp
Priority date: 2009-04-30
Filing date: 2009-04-30
Publication date: 2010-11-04

Abstract

Improved erosion control systems are provided which, in some embodiments, may comprise large, porous aggregate stabilized with a continuous mesh and a polymeric binding agent. In some embodiments, an erosion control system may include an aggregate layer comprising porous aggregate having a particle size of at least 7.5 mm and containing no more than 5% by weight of smaller particles; a continuous mesh disposed at an upper surface of the aggregate layer; and a polymer adhesive affixing at least some aggregate particles to each other and affixing the mesh to some of the aggregate particles, wherein the polymer adhesive permanently binds the aggregate and mesh such that the system remains porous. The polymer may be applied in-situ after the mesh has been placed on the aggregate.

Description

FIELD

The present invention relates to erosion control systems.

DESCRIPTION OF THE RELATED ART

Erosion control systems prevent soil loss from water flow. They are standard features on land development, construction and landfill projects. Soil loss not only reduces the land's physical and aesthetic attributes, it also has the potential to clog and pollute waterways. As a result there has been a heightened effort on the part of regulatory agencies to enforce strict erosion control practices.
Hard armor erosion control materials such as stone and concrete are used on the most challenging sites such as river channels and coastal revetments. The stability of stone aggregate may be improved by encasing the stone in gabions or grouting the stone in place.
Soft armor erosion control materials such as temporary or permanent rolled blankets are typically utilized to stabilize soils against sheet flow until vegetation is established.
Soil binders and hydraulic mulches utilize an emulsion or tackifier to stabilize a soil surface until vegetation is established. Soil binders and hydraulic mulches have been used with erosion control blankets to improve performance.
Polymer adhesives have been used to stabilize ballast below railroad tracks. Recently they have been utilized to improve coastal stone dikes. The polymer adhesives used for shoreline protection not only bind the stone aggregate but also retain the porosity of the stone. One exemplary method of constructing these maritime dikes is to mix the stone aggregate with a polymer adhesive in a tumbling machine (pre-processed) prior to placement. To date, in situ grouting of a prepared virgin stone aggregate layer has not provided sufficient erosion protection.
Thus, there is a need in the art for an improved erosion control system.

SUMMARY

Improved erosion control systems are provided which, in some embodiments, may comprise large, porous aggregate stabilized with a continuous mesh and a polymeric binding agent. In some embodiments, an erosion control system may include an aggregate layer comprising porous aggregate having a particle size of at least 7.5 mm and containing no more than 5% by weight of smaller particles; a continuous mesh disposed at an upper surface of the aggregate layer; and a polymer adhesive affixing at least some aggregate particles to each other and affixing the mesh to some of the aggregate particles, wherein the polymer adhesive permanently binds the aggregate and mesh such that the system remains porous. The polymer may be applied in-situ after the mesh has been placed on the aggregate.
In some embodiments, an erosion control system may include an aggregate layer comprising porous aggregate having a particle size of at least 7.5 mm and containing no more than 5% by weight of smaller particles; a continuous mesh disposed within 100 mm of the surface or no lower than two times the particle size of the aggregate when the particle size exceeds 50 mm; and a polymer adhesive affixing at least some aggregate particles to each other and affixing the mesh to some of the aggregate particles, wherein the polymer adhesive permanently binds the aggregate and mesh such that the system remains porous.
In some embodiments, a method of fabricating an erosion control system may include depositing an aggregate layer comprising a plurality of aggregate particles having a first diameter of at least 7.5 mm and no more than about 5% or less by weight of smaller particles; placing a mesh atop an upper surface of the aggregate layer; applying a polymer adhesive to a first plurality of the aggregate particles to form permanent bonds between the mesh and at least some of the aggregate particles in the upper region. In some embodiments, a polymer adhesive may be applied to a second plurality of the aggregate particles to form bonds between at least some of the aggregate particles in an upper region of the aggregate layer.
In accordance with some embodiments of the present invention, improved erosion control systems are provided. In some embodiments, the erosion control systems may meet one or more of the criteria of stability, durability, decreased environmental impact and low cost as well as ease and speed of installation.
In some embodiments, the erosion control system of the invention comprises a layer of large aggregate typically placed above a liner system. The large aggregate may enable turbulent flow at the surface and allow for in plane flow below the surface. The aggregate may have a particle size of at least 7.5 mm with no more than 5% by weight of smaller particles. The aggregate may be an open graded, washed stone. The liner system prevents finer soil materials from migrating or piping into the aggregate. The liner may be a geotextile, geomembrane, spray on liner, natural soil filter, or the like.
A top portion of the aggregate layer may include a continuous, integral mesh material. The mesh entangles with the aggregate stone. The mesh may be sized to resist raveling of treated stone through its structure. The mesh may be a geogrid, geonet, polymeric net, metal mesh, or the like. The mesh may be anchored at and/or within its periphery.
The aggregate in the top portion of the aggregate layer may be partially or fully enveloped in polymer. This polymer will bond the stones together and bond the stones to the mesh reinforcement. The polymer may be polyurethane. The polymer may be applied after the mesh has been placed over the aggregate (e.g., in-situ). The polymer may coat the stones and mesh without clogging the apertures between the materials.
Stabilizing forces that resist erosion on individual stones on the surface of a cover layer are weight, friction and interlocking with adjacent stones. A polymer bond between the stones will improve stability.
A mesh provides further stability. The stones can bear against the mesh. Also, the stones can transfer stress through polymer contact points to the mesh. In addition, the mesh can act as a lid on top of the stone to prevent rolling much like the lid of a gabion or wire mattress. The stresses imposed on the mesh through bearing, stone contact points and lid forces may be resisted by bearing and stone contact points in more stable areas of the mesh matrix upstream. Further anchorage may be provided by anchor trenches around and/or within the periphery of the aggregate layer. The above non-limiting summary of the invention is provided for reference only. Other and further embodiments and features of the present invention are disclosed in the detailed description below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the invention depicted in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 is a perspective view illustrating an erosion control system according to some embodiments of the invention.

FIG. 2 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 2.1 is a side view of an interior anchor trench according to some embodiments of the invention.

FIG. 2.2 is a side view of an interior anchor trench ballasted by large aggregate according to some embodiments of the invention.

FIG. 2.3 is a side view of a mesh seam according to some embodiments of the invention.

FIG. 3 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 4 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 5 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 6 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 7 is a side view of an erosion control system according to some embodiments of the invention.

FIG. 8 is a flow chart of a method for fabricating an erosion control system according to some embodiments of the invention.

The above Figures are not drawn to scale and are simplified for clarity. Embodiments of the invention described with respect to any of the above Figures may be combined with any other embodiments described herein to the extent not mutually exclusive.

DETAILED DESCRIPTION

Erosion control systems and methods of fabrication of same are provided herein. In some embodiments, the present invention provides improved erosion control systems having a porous aggregate layer stabilized with a continuous mesh and field applied polymer. The stabilized porous aggregate layer may be sized and dimensioned according to the particular requirements of the location to resist anticipated hydraulic forces. Further, the present invention may advantageously reduce the size of an aggregate particle, the thickness of an aggregate layer required, the environmental impact and/or reduce the thickness of the polymer treated aggregate layer. Further, increased stability from the mesh may advantageously reduce costs by simplifying and speeding construction.
In some embodiments, the erosion control system may further include a liner system disposed below the porous aggregate layer. The liner system may be anchored around and within its perimeter as needed for constructability and long term stability. The liner system may prevent finer subgrade particles from piping into the aggregate. If the design requires water to percolate into the subgrade, the liner may be fabricated from a geotextile or natural soil filter. If the design requires that the base of the erosion control system be impermeable, the liner may be fabricated from a geomembrane or spray on coating.
In some embodiments, the liner system may be provided in a desired location and a porous aggregate layer is dumped and spread on top of the liner system. The size and angularity of the aggregate, the depth of the aggregate layer and the compactive effort applied may be varied to provide optimum, or desired, resistance to hydraulic forces. Large aggregate is more stable because of its weight however, smaller aggregate is generally less expensive and easier to install. The porous aggregate may be stone, shell or recycled concrete, asphalt or glass. The bonding capacity between the aggregate and the polymer can be considered in the selection of the aggregate. The ability of the aggregate to entangle with the mesh can be considered in the selection of the aggregate. Typically, the aggregate can be processed angular stone gravel that is screened and washed to remove finer particles.
The location and strength of the mesh, its ability to bond with the polymer adhesive and its ability to confine and entangle with the aggregate are properties that will influence the performance of the inventive erosion control system. The location of the mesh within the top portion of the aggregate layer may be varied, as discussed below.
A perspective view of an exemplary erosion control system 100 is depicted in FIG. 1. The erosion control system 100 includes an aggregate layer 102 and a mesh 108 that are bonded together. The aggregate layer 102 includes a plurality of aggregate particles 103. The aggregate particles 103 can comprise stone, shell or recycled concrete, asphalt, glass, or combinations thereof. The aggregate particles may range in diameter. In some embodiments, the aggregate particles have a diameter of at least 7.5 mm. A diameter of at least 7.5 mm may be selected to promote turbulent flow at the surface of the erosion control system 100 while maintaining in-plane flow below the surface. The aggregate layer 102 may exclude smaller particles. In some embodiments, the aggregate layer 102 may include no more than about 5% by weight of particles that are smaller than 7.5 mm.
The aggregate layer 102 may range in thickness based on, for example, the desired application, or the strength of erosion forces being applied to the erosion control system 100. As a non-limiting example, in some embodiments, the aggregate layer 102 may be between about 150 to about 450 mm thick. Other thicknesses, greater and smaller, may be utilized as required for a particular application. For example, greater thickness aggregate layers may be required for revetment/dike applications.
At least a portion of the aggregate layer 102 may be treated with a polymer adhesive (e.g., partially or completely coated with a polymer adhesive) to form a polymer treated aggregate layer 104 having a plurality of polymer treated aggregate particles 105. A plurality of the polymer treated aggregate particles 105 may be bonded together, as discussed in more detail below. Examples of suitable polymer adhesives include, but are not limited to, polyurethane adhesives, and the like. One suitable polyurethane adhesive system is the Elastocoast® polyurethane adhesive system, available from Elastogran GmbH. Another suitable polymer adhesive is XiTRACK™ available from Dow Hyperlast.
The polymer treated aggregate layer 104 may be formed in the aggregate layer 102 proximate to and including an upper surface 106 of the aggregate layer 102. As discussed with respect to FIG. 8, below, the polymer treated aggregate layer 104 can be formed in situ (e.g., in the field) to permanently affix the mesh 108 to the upper surface 106 of the aggregate layer 102. As used herein, the term permanently refers to a desired design life of the structure such that the permanently bonded particles remain bonded together at least for the design life of the erosion control system. The polymer adhesive may be applied by grouting, spraying, painting, rolling, pouring, casting, or the like. The polymer treated aggregate layer 104 may range in thickness and uniformity as discussed below with respect to FIGS. 2-4.
The polymer treated aggregate layer 104 comprises polymer treated aggregate particles 105 formed from aggregate particle 103 covered by a polymer coating (not shown). In some embodiments, the polymer treated aggregate particles 105 may be completely coated or covered with the polymer. In some embodiments, the polymer treated aggregate particles 105 may be partially coated with the polymer. The polymer coating facilitates bonding between adjacent polymer treated aggregate particles to promote improved erosion resistance. Further, the polymer coating facilitates a permanent bonding between a plurality of polymer treated aggregate particles 105 and the mesh 108. The polymer treated aggregate layer 104 may be porous or impermeable, or may have both porous and impermeable regions.
The mesh 108 may be disposed atop the upper surface 106 of the aggregate layer 102 and may be permanently affixed, or bonded, to adjacent polymer treated aggregate particles 105 of the aggregate layer 102. The mesh 108 comprises, for example, a mesh material such as geogrid, geonet, polymeric net or metal mesh. The mesh 108 is typically continuous and may be a one-piece construction. Alternatively, the mesh 108 may include separate pieces of mesh material that are structurally joined, for example, by overlapping, being sewn together, interwoven, or otherwise joined, to form a continuous mesh.
A more detailed view of embodiments of the erosion control system 100 is depicted in FIG. 2, which shows a side view of the mesh 108 with the polymer treated aggregate layer 104 at the upper surface 106 of the aggregate layer 102. The mesh 108 may be installed directly on top of the aggregate layer 102. An illustrative direction of fluid flow over the surface of the erosion control system 100 is depicted by arrow 204.
The mesh 108 provides further stability of the erosion control system 100. For example, the mesh 108 can be sized to insure that aggregate particles 103 will not pass through the mesh 108. Individual stones, or particles 105 of the aggregate layer 102 can bear against the mesh 108 (as depicted by bearing points 202). Also, the particles 105 can transfer stress through polymer contact points to the mesh 108 (as depicted by mesh-to-aggregate polymer bonds 208). In addition, the mesh 108 can act as a lid on top of the stone to prevent rolling much like the lid of a gabion or wire mattress. The stresses imposed on the mesh 108 through bearing, stone contact points and lid forces may be resisted by bearing and stone contact points in more stable areas of the mesh matrix upstream. The additional stability afforded by the mesh 108, and the polymer adhesive bonds thereto, may compensate for the lower stability present in some conventional erosion control systems.
In some embodiments, further anchorage may be provided by anchor trenches around and/or within the periphery of the aggregate layer, as depicted in FIG. 2.1. Anchor trenches at the periphery or within the periphery of the aggregate layer may define one or more anchorage zones where the mesh is anchored. In embodiments where the upper surface 106 further includes a trench (302), exposed aggregate within a trench may be covered with a separate mesh (304) and adjoined (306) to a mesh at the upper surface 106. In some embodiments, the mesh 108 may be adjoined as described above and a fluid flow may be tangential to the upper surface 106 in a direction 204 as shown. In some embodiments, aggregate disposed in the anchorage zones may be not treated with a polymer adhesive. For example, FIG. 2.2 illustrates an embodiment where an interior trench (302) is anchored with large aggregate (306) that are independently stable without the need for polymer adhesive and/or a mesh restraint. In some embodiments, the aggregate within the anchorage zone may be stable due to one or more of the size, weight, or angularity of the aggregate, friction between the aggregate particles, or combinations thereof. At seams of adjoining mesh, as depicted in FIG. 2.3, an adjoining mesh upstream of the flow direction 204 may be placed over a mesh which is downstream of the flow direction 204, and secured (306) as necessary.
The polymer treated aggregate layer 104 facilitates forming aggregate-aggregate polymer bonds 206 (where individual polymer treated aggregate particles 105 bond together) and mesh-aggregate polymer bonds 208 (where the mesh 108 contacts individual polymer treated aggregate particles 105, as discussed above). In some embodiments, the polymer may be applied continuously across the upper surface 106 of the aggregate layer 102 to form the polymer treated aggregate layer 104. For example, as illustrated in FIG. 3, the polymer treated layer 104 may continuously span the aggregate layer 102. The polymer treated layer 104 may be formed to a substantially uniform depth within the aggregate layer 102.
Alternatively, the polymer treated aggregate layer 104 may discontinuously span the aggregate layer 102. For example, the polymer treated aggregate layer 104 may comprise a plurality of individual polymer treated regions 402, as shown in FIG. 4. In such a system, the mesh to aggregate bearing points are still continuously provided over the surface of the mesh 108. However, the mesh to aggregate polymer bonds (e.g., 208) will only be formed in the polymer treated regions 402. Each polymer treated region may have the same or different volume (length, width, or depth). In some embodiments, the plurality of polymer treated regions 402 may have a substantially uniform volume for all regions 402 in the plurality as shown. Alternatively, the volume of one or more regions 402 in the plurality may be varied by varying one or more of the length, width, and/or depth of the region 402. For example, to reduce cost or in areas where less stresses are expected to occur, some polymer treated regions 402 may be smaller than in volume than other polymer treated regions 402 in the system 100. In addition, the plurality of polymer treated regions 402 may be uniformly or non-uniformly spaced apart within the aggregate layer 102. In some embodiments, one or more of the polymer segment 402 may be placed in a region of the aggregate layer 102 experiencing increased erosion forces as compared to another region of the aggregate layer 102.
FIG. 5, for example, illustrates areas of relatively light or no polymer spaced between areas of concentrated applications of polymer. For example, a polymer treated aggregate layer 502 may be provided having first polymer treated regions 504 having a first depth 505 that greater than a second depth 507 of a second polymer treated region 506. The second polymer treated region 506 may couple two or more of the first polymer treated regions 504. The polymer treated aggregate layer 502 may have both porous and impermeable regions. For example, the first region 504 may be impermeable, and the second region 506 may be porous. In some embodiments, the polymer treated aggregate layer 502 may further include one or more polymer segments 402, as discussed above in FIG. 4.
In some embodiments, additional anchor aggregate may be provided to further stabilize the mesh 108. For example, as depicted in the erosion control system 600 of FIG. 6, an anchor aggregate layer 602 may be disposed atop the mesh 108 in one or more regions of the erosion control system 600. The erosion control system 600 may otherwise be similar to the embodiments of the erosion control system 100. In some embodiments, as illustrated in FIG. 7, an anchor aggregate layer 702 may be disposed continuously, or substantially continuously, atop the mesh 108 of an erosion control system 700. The erosion control system 700 may otherwise be similar to the embodiments of the erosion control system 100. The anchor aggregate layers 602, 702 each include polymer treated aggregate particles 604 which may be similar to the polymer treated aggregate particles 105, discussed above, or may be of a larger size.
In some embodiments, the anchor aggregate layer (602, 702) may have a thickness of up to about 100 mm. Alternatively, in embodiments where the diameter of the aggregate particles are greater than 50 mm, the anchor aggregate layer (602, 702) may have a thickness of up to about two times the average diameter of the aggregate particles
The anchor aggregate layer (602, 702) may increase the entanglement of the mesh 108 within an aggregate matrix (e.g., the aggregate particles disposed above and below the mesh 108). For example, the erosion control systems 600, 700 having the second aggregate layer 602, 702 disposed above the mesh 108 may provide improved entanglement of the mesh 108 as compared to the mesh 108 in the erosion control system 100. In some embodiments, the erosion control system 600, 700 may be advantageous when an aggregate-aggregate polymer bond is stronger than a mesh-aggregate polymer bond.
In some embodiments, where the erosion control system 600 experiences non-uniform erosion forces, the second aggregate layer 602 can be located atop one or more regions of the mesh 602 which experiences lower erosion forces. In some embodiments, the second aggregate layer 602 disposed atop the mesh 108 may be utilized in place of a trench 302 disposed in the aggregate layer 102.
Returning to FIG. 1, in some embodiments, the erosion control system 100 may further include a liner system 110. The liner system 110 may be anchored by any suitable means (not shown) around and/or within the perimeter of the liner system 110. Anchoring the liner may facilitate constructability of the erosion control system 100 and/or the long term stability thereof. For example, In some embodiments, the anchor may include spikes, nails, bearings or other suitable anchors. The liner system 110 can prevent finer subgrade particles, for example, such as sand, fines or the like, from piping, or diffusing, into the aggregate layer 102. In some embodiments, for example, if water is required to percolate into subgrade particles disposed below the liner system 110, the liner system 110 may comprise a geotextile or natural soil filter. In some embodiments, if the liner system 110 is required to be impermeable, a geomembrane or spray on coating may be used.

Example of a Virgin Aggregate Application

In some embodiments, for example as shown in FIG. 2, the mesh may be installed directly on top of virgin aggregate. The mesh may be sized to insure aggregate particles will not pass through its structure. The mesh may be anchored partially or fully around the periphery of the aggregate layer and in trenches within the aggregate layer. Exposed aggregate above interior trenches may be covered with a separate mesh and secured to mesh at the periphery of the trench (e.g., FIG. 2.1). At seams of the integral mesh the upstream portion of the mesh may be placed over the downstream portion in a shingle fashion and overlapped and secured as necessary (e.g., FIG. 2.3). The mesh may partially or fully entangle within the stone matrix upon placement. The polymer adhesive may then be applied in-situ. The polymer adhesive may be applied by grouting, spraying, painting, rolling, pouring, or casting. The polymer adhesive may be applied relatively uniformly over the aggregate/mesh surface (e.g., FIG. 3), concentrated in patches (e.g., FIG. 4) or a combination of the two application methods might be utilized (e.g., FIG. 5). After in-situ application of the polymer adhesive, the mesh may be more entangled within the aggregate matrix at the surface. The polymer adhesive will bond the aggregate particles to each other and the mesh to the aggregate at their contact points. Erosion of the uppermost aggregate is not possible if the mesh remains intact, anchored, and in intimate contact with the aggregate.
The mesh may be installed on top of the virgin aggregate. Additional virgin anchor aggregate may then be placed over the mesh, partially (e.g., FIG. 6) or totally (e.g., FIG. 7) covering the mesh. The anchor aggregate may increase the entanglement of the mesh within the aggregate matrix. The polymer adhesive may be applied relatively uniformly, concentrated in patches or a combination of the two application methods might be utilized. After in-situ application of the polymer adhesive the mesh may be more entangled within the aggregate matrix at or near the surface. The polymer adhesive will bond the aggregate particles to each other and the mesh to the aggregate at their contact points. In this scenario, the anchorage and the entanglement of the mesh may be superior to the scenario illustrated in FIG. 1, however the aggregate above the mesh will no longer be confined from above. This application might be advantageous where the bonds between the aggregate are stronger than the bonds between the mesh and the aggregate. This application might be advantageous where the anchor aggregate is located in areas experiencing lower erosion forces. This application might also reduce or eliminate the need for trenches within the aggregate layer.

Example of Pre-Processed Applications

In some embodiments, the mesh may be placed directly on top of aggregate that has been mixed with the polymer adhesive prior to placement (e.g., the aggregate may be pre-processed with the polymer adhesive). The polymer adhesive may then be applied in-situ to the mesh and the pre-processed aggregate layer.
In some embodiments, the mesh may be placed directly on top of aggregate that has been mixed with the polymer adhesive prior to placement (pre-processed). Additional virgin anchor aggregate may then be spread over the mesh, partially or totally covering the mesh. The polymer adhesive may then be applied in-situ to the virgin anchor aggregate, mesh, and pre-processed aggregate.
In some embodiments, the mesh may be placed directly on top of aggregate that has been mixed with the polymer adhesive prior to placement (pre-processed). Additional pre-processed aggregate (e.g., a pre-processed anchor aggregate layer) may then be spread over the mesh, partially or totally covering the mesh. The polymer adhesive may be applied in-situ to the mesh and pre-processed aggregate layer before and/or after the application of the pre-processed anchor aggregate layer.

Exemplary Methods of Fabrication

A flow chart for a method of fabricating an erosion control system is depicted in FIG. 8. The method 800 can be applied to fabricate embodiments of the erosion control system described above. The method 800 is described below with respect to FIGS. 1, 6, and 7.
The method 800 begins at 802 by depositing the aggregate layer 102. The aggregate layer 102 may be formed, for example, by depositing a plurality of aggregate particles 103 in a desired location. In some embodiments, the aggregate layer 102 may be formed atop a liner system 110. Selection of the size and angularity of the aggregate particles 103, the thickness of the aggregate layer 102 and the compactive effort applied to the aggregate layer 102 may be varied as desired. For example, in some embodiments, the aggregate particles 103 may comprise cobbles, for example having diameters of between about 75 mm to about 300 mm to increase stability of the erosion control system 100 due to increased weight. In some embodiments, the aggregate particles 103 may comprise small stone, such as gravel, for ease of installation and reduced cost. Selection of the aggregate particles 103 may further include a bonding capacity between the aggregate particles 103 and a polymer adhesive used to form the polymer treated aggregate layer 104, and/or the ability of the aggregate particles 103 to entangle with the mesh 108. In some embodiments, the aggregate particles 103 are processed angular stone gravel that is screened and washed to remove finer particles having diameters smaller than 7.5 mm.
In some embodiments, the aggregate particles 103 may be virgin aggregate particles, where virgin is intended to mean that the first aggregate particles are deposited without pre-processing, such as mixing with a polymer adhesive prior to deposition to form the aggregate layer 102. Alternatively, the aggregate particles 103 may be pre-processed prior to deposition by mixing the aggregate particles with a polymer adhesive prior to forming the aggregate layer 104.
Next, at 804, the mesh 108 is disposed atop the aggregate layer 102. Selection of a suitable mesh may include ability to permanently bind with the polymer adhesive, ability to entangle with the aggregate particles 102 and/or anchor aggregate particles 604, or the like. For example, the mesh 108 may be placed directly on top of the aggregate layer 102, where the aggregate particles are virgin aggregate particles or pre-processed aggregate particles.
Optionally, at 806, an anchor aggregate layer (602, 702) may be disposed atop the mesh 108 by depositing a plurality of anchor aggregate particles 604. The anchor aggregate layer may, for example, be disposed atop the mesh 108 in regions (e.g., FIG. 6) or continuously (e.g., FIG. 7). The anchor aggregate particles 604 may be deposited in either a pre-processed or virgin form. The anchor aggregate particles may be selected based on selection criteria for the aggregate particles 103, as discussed above. Further, selection criteria for the anchor aggregate particles 604 may include size, weight and angularity.
In some embodiments, such as the erosion control system depicted in FIGS. 6-7, a mesh may be placed directly on top of a pre-processed aggregate layer. Virgin anchor aggregate particles may then be spread over the mesh, partially (e.g., FIG. 6) or totally (e.g., FIG. 7) covering the mesh 108. A polymer adhesive may then be applied to the virgin anchor aggregate layer, mesh, and pre-processed aggregate layer, at 808 discussed below, to form a polymer treated aggregate layer. Alternatively, the anchor aggregate particles may be pre-processed prior to deposition.
At 808, a polymer adhesive may be applied to permanently affix the mesh to the upper surface of the aggregate layer 102 (e.g., to a plurality of aggregate particles forming the aggregate layer 102). In some embodiments, the polymer adhesive may be applied at least to the mesh 108. In some embodiments, the polymer adhesive may be applied to an aggregate layer 102 comprising virgin aggregate particles as well as to the mesh 108. In some embodiments, the polymer adhesive may be applied to the mesh 108 and an aggregate layer 102 comprising pre-processed aggregate particles. In some embodiments, the polymer adhesive may be applied to the anchor aggregate layer 602, 702. In some embodiments, the polymer adhesive may be applied to all layers, or a subset of all layers, simultaneously (e.g., in the same application of the adhesive). Upon completion of applying the polymer adhesive at 808, the method 800 generally ends.
Thus, embodiments of an improved erosion control system are provided herein. The erosion control system provides a superior erosion control system and a less expensive construction practice. In addition, the present invention may reduce the size of the aggregate, reduce the depth of the aggregate layer, reduce the environmental impact and/or reduce the depth and quantity of the polymeric treatment.
Non-limiting examples of embodiments of the present invention include: the use of a continuous mesh in combination with an in-situ applied polymer to secure the surface and near surface area of a porous, large aggregate erosion control layer; the use of a polymer to affix a continuous mesh lid directly to the surface of a porous, large aggregate erosion control layer; the use of a polymer to affix an anchored, continuous mesh to large aggregate particles being pushed by erosion forces; and the use of a polymer to anchor a continuous mesh, which restrains the movement of large aggregate particles from erosion forces, by affixing the mesh to large aggregate upstream of the restrained aggregate.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.

Claims

1. An erosion control system, comprising:

an aggregate layer comprising porous aggregate having a particle size of at least 7.5 mm and containing no more than 5% by weight of smaller particles;

a continuous mesh disposed at an upper surface of the aggregate layer; and

a polymer adhesive affixing at least some aggregate particles to each other and affixing the mesh to some of the aggregate particles, wherein the polymer adhesive permanently binds the aggregate and mesh such that the system remains porous.

2. The system of claim 1, wherein the polymer adhesive is applied in-situ after the mesh has been placed on the aggregate.

3. The system of claim 1, wherein the polymer adhesive is disposed substantially uniformly in the upper region of the porous aggregate.

4. The system of claim 1, wherein the polymer adhesive is applied in a pattern with areas of heavier application spaced between areas of lighter or no application.

5. The system of claim 4, wherein the areas of heavier application are impermeable.

6. The system of claim 1, wherein the mesh is anchored at its periphery.

7. The system of claim 1, wherein the mesh is anchored within its periphery.

8. The system of claim 7, wherein the aggregate within an anchorage zone where the mesh is anchored is not treated with a polymer adhesive.

9. The system of claim 8, wherein the aggregate within the anchorage zone is stable due to one or more of size, weight, friction, angularity or combinations thereof.

10. The system of claim 1, further comprising:

an anchor aggregate layer disposed atop the mesh.

11. An erosion control system, comprising:

a continuous mesh disposed within 100 mm of the surface or no lower than two times the particle size of the aggregate when the particle size exceeds 50 mm; and

12. The system of claim 11, wherein the polymer adhesive is applied in-situ after the mesh has been placed on the aggregate.

13. The system of claim 11, wherein the polymer adhesive is disposed substantially uniformly in the upper region of the porous aggregate.

14. The system of claim 11, wherein the polymer adhesive is applied in a pattern with areas of heavier application spaced between areas of lighter or no application.

15. The system of claim 14, wherein the areas of heavier application are impermeable.

16. The system of claim 11, wherein the mesh is anchored at its periphery.

17. The system of claim 11, wherein the mesh is anchored within its periphery.

18. A method of fabricating an erosion control system, comprising:

depositing an aggregate layer comprising a plurality of aggregate particles having a first diameter of at least 7.5 mm and no more than about 5% or less by weight of smaller particles;

placing a mesh atop an upper surface of the aggregate layer;

applying a polymer adhesive to a first plurality of the aggregate particles to form permanent bonds between the mesh and at least some of the aggregate particles in the upper region.

19. The method of claim 18, further comprising:

applying a polymer adhesive to a second plurality of the aggregate particles to form bonds between at least some of the aggregate particles in an upper region of the aggregate layer.

20. The method of claim 18, wherein applying the polymer adhesive to the plurality of the aggregate particles to form bonds between at least some of the aggregate particles further comprises:

mixing the plurality of aggregate particles with the polymer adhesive prior to deposition of the aggregate layer.

21. The method of claim 18, further comprising:

depositing an anchor aggregate layer atop the mesh.

22. The method of claim 21, wherein anchor aggregate particles of the anchor aggregate layer are mixed with a polymer adhesive prior to deposition of the anchor aggregate layer.

23. The method of claim 21, wherein the anchor aggregate layer is deposited such that one or more regions of the mesh remain exposed.