US20120064263A1 - Wind-resistant environmental synthetic cover - Google Patents

Wind-resistant environmental synthetic cover Download PDF

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Publication number
US20120064263A1
US20120064263A1 US13/231,688 US201113231688A US2012064263A1 US 20120064263 A1 US20120064263 A1 US 20120064263A1 US 201113231688 A US201113231688 A US 201113231688A US 2012064263 A1 US2012064263 A1 US 2012064263A1
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United States
Prior art keywords
wind
synthetic
cover
cover system
exposed
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Abandoned
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US13/231,688
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English (en)
Inventor
Michael Ayers
Jose URRUTIA
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Closureturf LLC
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Closureturf LLC
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Priority to US13/231,688 priority Critical patent/US20120064263A1/en
Assigned to CLOSURETURF, LLC reassignment CLOSURETURF, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AYERS, MICHAEL, URRUTIA, JOSE
Assigned to SHAW INDUSTRIES GROUP, INC. reassignment SHAW INDUSTRIES GROUP, INC. SECURITY AGREEMENT Assignors: CLOSURETURF LLC
Publication of US20120064263A1 publication Critical patent/US20120064263A1/en
Priority to US14/721,633 priority patent/US20150252525A1/en
Abandoned legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N7/00—Flexible sheet materials not otherwise provided for, e.g. textile threads, filaments, yarns or tow, glued on macromolecular material
    • D06N7/0092—Non-continuous polymer coating on the fibrous substrate, e.g. plastic dots on fabrics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B1/00—Dumping solid waste
    • B09B1/004—Covering of dumping sites
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2201/00—Chemical constitution of the fibres, threads or yarns
    • D06N2201/02—Synthetic macromolecular fibres
    • D06N2201/0254—Polyolefin fibres
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2209/00—Properties of the materials
    • D06N2209/10—Properties of the materials having mechanical properties
    • D06N2209/103—Resistant to mechanical forces, e.g. shock, impact, puncture, flexion, shear, compression, tear
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/30—Landfill technologies aiming to mitigate methane emissions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/23907—Pile or nap type surface or component
    • Y10T428/2395—Nap type surface
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/23907—Pile or nap type surface or component
    • Y10T428/23957—Particular shape or structure of pile
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/23907—Pile or nap type surface or component
    • Y10T428/23979—Particular backing structure or composition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component

Definitions

  • Environmental covers are used to covers landfills, mines, stockpiles and other waste materials to minimize rain infiltration that can contaminate the groundwater table below. These covers often use synthetic liner materials that are typically covered with two feet of soil that can support natural vegetation. Some of these environmental caps are described in the United States Environmental Protection Agency (40 CFR Sub. D) environmental regulations.
  • Environmental covers are also used with geosynthetic liner materials that are not covered with soil. In this case the impermeable geomembrane is exposed to the environment. However this type of exposed geosynthetic cover requires extensive anchoring and or ballasting to protect the cover against wind uplift in the presence of strong winds.
  • the anchoring system can be very extensive resulting in large construction costs.
  • exposed covers require the cover to be held down by the use of ropes and tires (ballast) spaced a few feet apart and/or numerous anchor trenches across the slope where ballast material can be placed atop the cover in the anchor trenches to protect the liners against the wind uplift.
  • ballast material can be placed atop the cover in the anchor trenches to protect the liners against the wind uplift.
  • sand tubes are used to ballast the geosynthetic liner/synthetic cover against the wind.
  • the exposed geosynthetic liner material also weathers more rapidly as a result of lack of a protective cover.
  • Exposed impermeable geomembranes have been used for the closures of landfills and various man made stockpiles. However, such covers with an exposed membrane generally have negative aesthetics and require extensive anchoring or ballasting.
  • Artificial grass or synthetic grass has been extensively used in sports arenas as well as airport runways and general landscaping. However, a primary consideration of artificial turf fields is the ability of the field to drain moisture therethrough, such as to keep the athletic field playable by avoiding puddling. In environmental covers, the opposite is desired. In environmental covers, it is desired that moisture not drain through the cover and environmental covers generally require the use of an impermeable surface to avoid rainfall infiltration through the cover and into the soil below.
  • ballasting techniques are expensive, often impractical and their effectiveness is typically limited to winds below about 40 mph. Additionally, this type of cover only last a few years due to damage from wind. Accordingly, it can be seen that there exists a need for a wind-resistant liner that doesn't require the expense and trouble of ballasts. It is to the provision of solutions to this and other problems that the present invention is primarily directed.
  • the present invention provides a new and useful system for covering (i.e., closing) various types of sites where waste is deposited.
  • the cover system of this invention comprises a composite of one or more geotextiles that are tufted with synthetic yarns and an impermeable geomembrane, which is comprised of a polymeric material.
  • the geotextiles can comprise polypropylene or polyethylene.
  • the present invention comprises a wind-resistant cover, including textured synthetic slender elongate elements, such as vertical filaments, secured over a low-permeable polymer liner backing.
  • the system does not rely on piled-on weight to resist wind forces and optionally the cover of the present invention can be deployed over a large area with little or no ballasting or anchoring. This new cover breaks up the airflow over the cover, providing wind uplift resistance.
  • the cover includes vertical filaments attached to the liner to break the wind aero-dynamics on the exposed cover.
  • the wind velocity on the impermeable surface membrane
  • the cover now becomes turbulent near the surface of the cover, thus greatly reducing the actual wind velocity at the liner surface and decreasing associated uplift.
  • the reaction of the slender elongate elements to the wind forces may also create a downward force on the membrane. This reaction may be caused by the filaments applying an opposing force against the wind which is transferred as a downward force on the membrane.
  • the use of vertical slender elongate elements amounts to a radical departure from the typical exposed membranes or liners.
  • Optional examples of slender elongate elements contemplated as encompassed by the present invention or in conjunction therewith include structures that resemble blades of grass, rods, filaments, tufts, follicle-like elements, fibers, narrow cone-shaped elements, etc.
  • the wind-resistant cover in this invention can create a larger distance from the material surface to the “free stream” (free stream occurs where the wind flow is unaffected by the material).
  • the cover breaks up the flow stream, increasing the boundary layer (distance from surface to free stream) to the point where uplift forces are very small. This is in stark contrast to a prior art cover with an exposed membrane, where there is a minuscule distance to the uninterrupted free-stream air flow. This small boundary means that there is a large velocity differential over a very short distance creating much higher uplift.
  • the positive/downward force is a result of a reaction of the synthetic cover, with the individual blades acting as spring pushing against the wind.
  • This reaction and opposing force will vary based on the type of cover and the length of the synthetic blade of grass. The blade will be shorter or longer depending on the wind design flow for the disruption provided by the synthetic cover of this invention.
  • the synthetic cover portion of this environmental closure also acts as a protective layer providing protection from physical damage and weathering to the geomembrane liner below.
  • the present invention can extend the longevity of the geomembrane component over a much longer period of time in comparison with the conventional exposed geomembrane covers.
  • This invention in a preferred form, uses a lower geomembrane with roughened or structural components to increase the friction resistance against the lower soil and interface friction between the cover and the geomembrane.
  • the angle of friction can be higher than 18 degrees.
  • the liner can also be affixed to the cover by spraying polypropylene or polyethylene to the back of tufted or knitted geotextile(s).
  • FIG. 1 is a schematic view of prior art environmental cover as per the United States Environmental Protection Agency where the anchoring of the impermeable geosynthetic membrane consists of a two foot soil cover.
  • FIG. 2 is a schematic view of a second prior art environmental cover with exposed geomembranes that require extensive anchoring to resist wind uplift.
  • FIG. 2.1 depicts prior art arrangements and in general shows a cross sectional view of anchor trenches used along the slope of an exposed geomembrane cover to secure it in place in the face of wind which would otherwise tend to lift the cover.
  • FIGS. 2A , 2 B, 3 , 3 . 1 , 4 , and 5 consist of schematic views of a wind-resistant environmental cover/liner according to a first preferred form of the present invention.
  • FIG. 1 depicts a cross sectional view of a typical cover system as described in current United States Environmental Protection Agency federal regulations and as used in the covers for landfills and mines. In this case the two feet of soil is used to cover the geomembrane against wind uplift.
  • FIG. 2 depicts a prior art cover where the geomembrane is exposed to the environment.
  • the system requires extensive anchoring in order to resist wind uplift forces.
  • FIG. 2.1 depicts prior art covers of exposed geomembrane arrangements and in general shows a cross sectional view of anchor trenches ( 30 ) used along the slope of an exposed geomembrane cover to secure it in place in the face of wind which would otherwise tend to lift the cover.
  • the figure shows the geomembrane/raincoat cover ( 12 ), and the use of tires ( 20 ) tied with ropes as additional ballasting system of the exposed geomembrane ( 12 ).
  • This type of prior art anchoring required to resist uplift is very expensive and it is not aesthetically pleasant.
  • FIG. 2A and 2B schematically depict the current invention with an exposed geomembrane or raincoat liner ( 102 ) covered with synthetic strands ( 103 ) that resemble grass with a pile height ranging from about 3 ⁇ 4 inch to 2 inches depending on wind design velocities.
  • the strands ( 103 ) tend to break the laminar flow of the wind and also provide normal pressure on the geomembrane liner system when the strands bend onto the liner, creating normal pressure.
  • the pile height is 3 ⁇ 4 inch to 2 inches or so. More preferably, the pile height is about 1 inch to 1-1 ⁇ 2 inches.
  • the synthetic strands ( 103 ) are slender elongate elements.
  • “slender” indicates a length that is much greater than its transverse dimension(s).
  • Examples of slender elongate elements contemplated as encompassed by the present invention or in conjunction therewith are structures that resemble blades of grass, rods, filaments, tufts, follicle-like elements, fibers, narrow cone-shaped elements, etc.
  • the synthetic strands extend upwardly from a base and form a mat or field of such strands. Such can simulate a field of grass, pine straw or similar.
  • blade-like elements grass blade-like, not necessarily like cutting blades
  • the chemical composition of the synthetic grass blades ( 103 ) should be selected to be heat-resistant and UV-resistant (and to withstand exposure to sunlight, which generates heat in the blades and contains ultraviolet rays).
  • the polymer yarns ( 103 ) should not become brittle when subjected to low temperatures.
  • the selected synthetic grass color and texture should be aesthetically pleasing. While various other materials may work well for the grass blades, it is presently believed that polyethylene fibers work best.
  • the synthetic grass blades ( 103 ) are tufted to have a density of between about 20 ounces/square yard and about 100 ounces/square yard.
  • the synthetic grass blades Preferably, have a density of between about 20 and 40 ounces/square yard.
  • the tufting is fairly homogeneous.
  • a “loop” is inserted at a gauge spacing to achieve the desired density. Each loop shows as two blades of grass at each tufted location.
  • the synthetic grass blades have a thickness of at least about 100 microns.
  • the synthetic grass blades ( 103 ) are tufted into the geotextile backing ( 104 ).
  • the geotextile backing preferably consists of one or more geotextiles made of polypropylene or polyethylene with UV stabilizers.
  • the geotextiles can comprise slit film (tape yarn) or monofilament.
  • slit film tape yarn
  • monofilament geotextiles typically have a small cross section relative to their length, which inherently provides for a smaller surface exposed to UV light per unit weight of polypropylene or polyethylene. In other words, a yarn with a round cross-section typically will exhibit better UV resistance than a flat geometric shape.
  • the geotextile backing ( 104 ) can be a single layer backing, a double layer backing, or can have more than two layers. But it is preferred that a single layer or double layer backing be used.
  • the backing can be made of polypropylene or polyethylene.
  • a separate membrane can be dispensed with, such as by applying a membrane-like layer to the back side of the synthetic geotextile. For example, a urethane coating can be sprayed onto the back of the synthetic geotextile and allowed to cure.
  • FIG. 2.1 The prior art technique of using tarps or geomembranes to cover leach pads, landfills and stockpiles to protect the ore, waste and soil stockpiles from rain and weather damage typically requires substantial ballast or anchorage as shown on FIG. 2.1 .
  • This new invention allows the use of a membrane over large areas without such ballast or anchorage.
  • a synthetic cover layer ( 100 ) is provided that can resist wind uplift and thus protecting the impermeable geomembrane ( 102 ) below.
  • the synthetic cover ( 100 , 103 ) contains grass-like filaments covering and protecting the impermeable geomembrane liner surface.
  • the inventive wind-resistant cover and liner was laboratory tested (at the Georgia Tech Research Institute (“GTRI”) Wind Tunnel Lab) using wind tunnels to determine the uplift vertical pressures and shear pressures on the synthetic cover.
  • the wind tunnel trials indicated that this novel cover resists the uplift forces of the wind.
  • Minimal product weight of 0.3 lbs/sq-ft typically will be required to counteract the shear forces from the wind.
  • Synthetic grass and geomembranes in the range of 30 to 40 mil thickness would exceed this minimum weight-per-unit area threshold.
  • the present inventors have confirmed the performance of this novel cover by testing the same as landfill covers for mines and general covers for ore stockpiles, dams, embankments, general stockpiles and the like.
  • FIG. 4 shows the boundary layer profile for two conditions.
  • the lower curve shows the wind profile at the edges and the upper curves represents the wind profile in the interior conditions of the cover defined in this invention.
  • the wind subjects the cover ( 103 ) to up to 89% of the total free stream.
  • the blades are subject to higher velocities and thus higher increasing drag as the wind speed increases.
  • the higher drag increases the bending of the blades back onto the backing geotextile(s) ( 104 ).
  • the effect of this has two counteracting impacts on the net lift.
  • the synthetic blades ( 103 ) are bent slightly with flow being deflected and accelerated over the edges.
  • This flow acceleration increases the local velocity and lowers the local static pressure below that of the stream static, which creates the pressure differential building up with the associated uplift of the cover geotextiles ( 104 ). This force can be counteracted by building an anchor trench at the perimeter of the cover.
  • FIG. 4 For the interior condition FIG. 4 (upper curve) approximately 18 inches from the edge, the curve is drastically different than the perimeter boundary. Compared with the perimeter profile it is 25% thicker with no measurable velocity until the height is greater than 50% of the cover length. The blades ( 103 ) therefore experience a maximum 45% of the free stream velocity. This reduces the drag action on the cover layer. Furthermore, the static pressure remains constant as a function of height through the boundary which effectively prevents the formation of pressure differential (i.e., no uplift) at the geomembrane/geotextile surface.
  • pressure differential i.e., no uplift
  • the wind-resistant cover of this invention creates a larger distance from the material surface to the “free stream” (free stream occurs where the wind flow is unaffected by the material).
  • the cover radically breaks up the flow stream, increasing the boundary layer (distance from surface to free stream) to the point where uplift forces are very small. This is in stark contrast to a prior art exposed membrane cover, in which there is a minuscule distance from the surface (where velocity is 0 feet per second, which is the case for all materials and wind conditions) to free stream.
  • boundary layer conditions are created by longer flow paths over a given surface and all boundaries grow in thickness and increase in turbulence with increasing distance.
  • the interaction of the flow with the flexible blades causes the boundary layer growth to occur quite rapidly. It is also clearly seen in our experiments that little to no deflection occurred in the cover at a distance just over 6 inches from the perimeter edge.
  • the measured uplift results show values requiring minimal uplift resistance that can simply be achieved by the weight of the cover itself.
  • Exposed geomembrane covers have been used extensively in the past as covers for landfills and stockpiles in the solid waste and mining industries in order to prevent or minimize rainwater infiltration into the waste or the ore.
  • UV-resistance of the liner materials has not been a concern when HDPE and LLDPE, PVC materials are used as the plastic materials.
  • the blades can be made of polyethylene, HDPE, LLDPE, PVC, or other UV-resistant material. While UV resistance is not an absolute requirement, it does provide an important long-term stability for the synthetic grass blades, adding to the overall performance of the system.
  • FIG. 1 depicts a cross sectional view of a typical cover system as described in current United States Environmental Protection Agency federal regulations and as used in the covers for landfills and mines.
  • the two feet of soil is used to cover the geomembrane against wind uplift.
  • the waste W is covered by eighteen inches of soil ( 11 ), then a 40 mil. geomembrane GM, a geocomposite drainage media D, eighteen more inches of soil S, six inches of topsoil TS, and finally vegetive grass G.
  • FIG. 2 depicts a prior art cover where the geomembrane is exposed to the environment.
  • the system requires extensive anchoring in order to resist wind uplift forces.
  • the waste W is covered by eighteen inches of soil S and an exposed geomembrane 12 .
  • FIG. 2.1 depicts prior art covers of exposed geomembrane arrangements and in general shows a cross sectional view of anchor trenches ( 30 ) used along the slope of an exposed geomembrane cover to secure it in place in the face of wind which would otherwise tend to lift the cover.
  • the figure shows the geomembrane/raincoat cover ( 12 ), and the use of tires ( 20 ) tied with ropes as additional ballasting system of the exposed geomembrane ( 12 ).
  • This type of prior art anchoring required to resist uplift is very expensive and it is not aesthetically pleasant.
  • FIG. 2A and 2B schematically depict the current invention over waste W covered with soil ( 101 ) with an exposed geomembrane or raincoat liner ( 102 ) covered with synthetic strands ( 103 ) that resemble grass with a pile height ranging from about 3 ⁇ 4 inch to 2 inches depending on wind design velocities.
  • the strands ( 103 ) tend to break the laminar flow of the wind and also provide normal pressure on the geomembrane liner system when the strands bend onto the liner, creating normal pressure.
  • the pile height is % inch to 2 inches or so. More preferably, the pile height is about 1 inch to 1-1 ⁇ 2 inches.
  • the synthetic strands ( 103 ) are slender elongate elements.
  • “slender” indicates a length that is much greater than its transverse dimension(s).
  • Examples of slender elongate elements contemplated as encompassed by the present invention or in conjunction therewith are structures that resemble blades of grass, rods, filaments, tufts, follicle-like elements, fibers, narrow cone-shaped elements, etc.
  • the synthetic strands extend upwardly from a base and form a mat or field of such strands. Such can simulate a field of grass, pine straw or similar.
  • blade-like elements grass blade-like, not necessarily like cutting blades
  • the chemical composition of the synthetic grass blades ( 103 ) should be selected to be heat-resistant and UV-resistant (and to withstand exposure to sunlight, which generates heat in the blades and contains ultraviolet rays).
  • the polymer yarns ( 103 ) should not become brittle when subjected to low temperatures.
  • the selected synthetic grass color and texture should be aesthetically pleasing. While various other materials may work well for the grass blades, it is presently believed that polyethylene fibers work best.
  • the synthetic grass blades ( 103 ) are tufted to have a density of between about 20 ounces/square yard and about 100 ounces/square yard.
  • the synthetic grass blades Preferably, have a density of between about 20 and 40 ounces/square yard.
  • the tufting is fairly homogeneous.
  • a “loop” is inserted at a gauge spacing to achieve the desired density. Each loop shows as two blades of grass at each tufted location.
  • the synthetic grass blades have a thickness of at least about 100 microns.
  • the synthetic grass blades ( 103 ) are tufted into the geotextile backing ( 104 ).
  • the geotextile backing preferably consists of one or more geotextiles made of polypropylene or polyethylene with UV stabilizers.
  • the geotextiles can comprise slit film (tape yarn) or monofilament.
  • slit film tape yarn
  • monofilament geotextiles typically have a small cross section relative to their length, which inherently provides for a smaller surface exposed to UV light per unit weight of polypropylene or polyethylene. In other words, a yarn with a round cross-section typically will exhibit better UV resistance than a flat geometric shape.
  • the geotextile backing ( 104 ) can be a single layer backing, a double layer backing, or can have more than two layers. But it is preferred that a single layer or double layer backing be used.
  • the backing can be made of polypropylene or polyethylene.
  • a separate membrane can be dispensed with, such as by applying a membrane-like layer to the back side of the synthetic geotextile. For example, a urethane coating can be sprayed onto the back of the synthetic geotextile and allowed to cure.
  • FIG. 2.1 The prior art technique of using tarps or geomembranes to cover leach pads, landfills and stockpiles to protect the ore, waste and soil stockpiles from rain and weather damage typically requires substantial ballast or anchorage as shown on FIG. 2.1 .
  • This new invention allows the use of a membrane over large areas without such ballast or anchorage.
  • a synthetic cover layer ( 100 ) is provided that can resist wind uplift and thus protecting the impermeable geomembrane ( 102 ) below.
  • the synthetic cover ( 100 , 103 ) contains grass-like filaments covering and protecting the impermeable geomembrane liner surface.
  • the inventive wind-resistant cover and liner was laboratory tested (at the Georgia Tech Research Institute (“GTRI”) Wind Tunnel Lab) using wind tunnels to determine the uplift vertical pressures and shear pressures on the synthetic cover.
  • the wind tunnel trials indicated that this novel cover resists the uplift forces of the wind.
  • Minimal product weight of 0.3 lbs/sq-ft typically will be required to counteract the shear forces from the wind.
  • Synthetic grass and geomembranes in the range of 30 to 40 mil thickness would exceed this minimum weight-per-unit area threshold.
  • the present inventors have confirmed the performance of this novel cover by testing the same as landfill covers for mines and general covers for ore stockpiles, dams, embankments, general stockpiles and the like.
  • FIG. 4 shows the boundary layer profile for two conditions.
  • the lower curve shows the wind profile at the edges and the upper curves represents the wind profile in the interior conditions of the cover defined in this invention.
  • the wind subjects the cover ( 103 ) to up to 89% of the total free stream.
  • the blades are subject to higher velocities and thus higher increasing drag as the wind speed increases.
  • the higher drag increases the bending of the blades back onto the backing geotextile(s) ( 104 ).
  • the effect of this has two counteracting impacts on the net lift.
  • the synthetic blades ( 103 ) are bent slightly with flow being deflected and accelerated over the edges.
  • This flow acceleration increases the local velocity and lowers the local static pressure below that of the stream static, which creates the pressure differential building up with the associated uplift of the cover geotextiles ( 104 ). This force can be counteracted by building an anchor trench at the perimeter of the cover.
  • FIG. 4 For the interior condition FIG. 4 (upper curve) approximately 18 inches from the edge, the curve is drastically different than the perimeter boundary. Compared with the perimeter profile it is 25% thicker with no measurable velocity until the height is greater than 50% of the cover length. The blades ( 103 ) therefore experience a maximum 45% of the free stream velocity. This reduces the drag action on the cover layer. Furthermore, the static pressure remains constant as a function of height through the boundary which effectively prevents the formation of pressure differential (i.e., no uplift) at the geomembrane/geotextile surface.
  • pressure differential i.e., no uplift
  • the wind-resistant cover of this invention creates a larger distance from the material surface to the “free stream” (free stream occurs where the wind flow is unaffected by the material).
  • the cover radically breaks up the flow stream, increasing the boundary layer (distance from surface to free stream) to the point where uplift forces are very small. This is in stark contrast to a prior art exposed membrane cover, in which there is a minuscule distance from the surface (where velocity is 0 feet per second, which is the case for all materials and wind conditions) to free stream.
  • boundary layer conditions are created by longer flow paths over a given surface and all boundaries grow in thickness and increase in turbulence with increasing distance.
  • the interaction of the flow with the flexible blades causes the boundary layer growth to occur quite rapidly. It is also clearly seen in our experiments that little to no deflection occurred in the cover at a distance just over 6 inches from the perimeter edge.
  • the measured uplift results show values requiring minimal uplift resistance that can simply be achieved by the weight of the cover itself.
  • Exposed geomembrane covers have been used extensively in the past as covers for landfills and stockpiles in the solid waste and mining industries in order to prevent or minimize rainwater infiltration into the waste or the ore.
  • UV-resistance of the liner materials has not been a concern when HDPE and LLDPE, PVC materials are used as the plastic materials.
  • the blades can be made of polyethylene, HDPE, LLDPE, PVC, or other UV-resistant material. While UV resistance is not an absolute requirement, it does provide an important long-term stability for the synthetic grass blades, adding to the overall performance of the system.
  • FIG. 5 shows synthetic strands ( 103 ) over a geomembrane ( 102 ) atop subgrade soil ( 101 ), with anchor trenches ( 300 ) at the leading edges only.

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US13/231,688 2010-09-13 2011-09-13 Wind-resistant environmental synthetic cover Abandoned US20120064263A1 (en)

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US20120064262A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic grass cover for mse walls
USD667228S1 (en) * 2009-09-24 2012-09-18 Yuyama Manufacturing Co., Ltd. Sheet for a drug bag
WO2015050828A2 (en) 2013-09-26 2015-04-09 Watershed Geosynthetics Llc Earthwork basket with synthetic turf facing
WO2015053977A1 (en) 2013-10-10 2015-04-16 Watershed Geosynthetics Llc Formed in place filled structure with synthetic turf
WO2015126996A1 (en) * 2014-02-21 2015-08-27 Watershed Geosynthetics Llc Synthetic ground cover system for erosion control
USD818206S1 (en) 2016-09-30 2018-05-15 Clear-Coat Holding Company Olfactory mat structure for an olfactory mat for domestic animals
US10058904B2 (en) 2016-03-08 2018-08-28 Commercial Liability Partners, Llc Waste disposal closure system
US20190161931A1 (en) * 2017-11-28 2019-05-30 Watershed Geosynthetics Llc Water flow control ground cover
US10465316B2 (en) 2015-08-20 2019-11-05 Glen Raven, Inc. Outdoor fabric
CN110835877A (zh) * 2019-11-15 2020-02-25 湖北绿城体育产业有限公司 一种改良热熔型环保人造草及其制作方法
WO2020047533A1 (en) * 2018-08-31 2020-03-05 Watershed Geosynthetics Llc Tufted geotetxtile with increased shear resistance to hydraulic infill displacment and dry-flow loading
US10582697B2 (en) 2016-07-26 2020-03-10 Curio Holding Company Olfactory mat for domestic animals
CN111424687A (zh) * 2020-04-20 2020-07-17 中国科学院地质与地球物理研究所 一种利用磷石膏与微生物矿化技术用于膨胀土边坡生态防护的施工方法
US20210141121A1 (en) * 2019-11-13 2021-05-13 Jiangxi Academy Of Environmental Sciences Structure and method for three-dimensional restoration of slope soil in abandoned ion-absorbed rare earth mining area
US11045847B2 (en) 2013-10-29 2021-06-29 Watershed Geosynthetics Llc Geocomposite covering
US20210292979A1 (en) * 2016-03-17 2021-09-23 Watershed Geosynthetic LLC Ballast System For Roof Protection
US11277091B2 (en) 2017-06-20 2022-03-15 Watershed Solar LLC Integrated photovoltaic module mounting system for use with tufted geosynthetics

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GB201704132D0 (en) 2017-03-15 2017-04-26 Thomas & Fontaine Ltd A net

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US20120063854A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic ground cover system for erosion protection for use with or without a sand/soil ballast
US20120064262A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic grass cover for mse walls

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CA2503256A1 (en) * 2004-04-06 2005-10-06 Claude J. Degarie Membrane cover having a protective layer to prevent deterioration of uv stabilizers therein
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US9587364B2 (en) * 2011-03-11 2017-03-07 Watershed Geosynthetics Llc Synthetic ground cover system with impermeable backing and binding infill for erosion control
MX337616B (es) * 2011-03-11 2016-03-10 Watershed Geosynthetics Llc Sistema sintetico de cubierta para suelos con relleno adherente para control de la erosion.
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US3332828A (en) * 1965-12-28 1967-07-25 Monsanto Co Monofilament ribbon pile product
US4946719A (en) * 1988-12-05 1990-08-07 Astroturf Industries, Inc. Drainable artificial turf assembly
US7357966B2 (en) * 2004-08-31 2008-04-15 New England Soccer School, Llc Synthetic turf system and method
US20060045995A1 (en) * 2004-08-31 2006-03-02 Ted Dipple Synthetic turf system and method
US20070009680A1 (en) * 2004-08-31 2007-01-11 Ted Dipple Synthetic turf system and method
US20060045994A1 (en) * 2004-08-31 2006-03-02 Ted Dipple Synthetic turf system and method
US20080069642A1 (en) * 2006-09-14 2008-03-20 Ayers Michael R Cover system for waste sites and environmental closures
US20100266342A1 (en) * 2006-09-14 2010-10-21 Ayers Michael R Cover system for waste sites
US20100272516A1 (en) * 2006-09-14 2010-10-28 Ayers Michael R Cover system with gas collection system for waste sites and environmental closures
US8403597B2 (en) * 2006-09-14 2013-03-26 Closureturf Llc Cover system for waste sites
US8585322B2 (en) * 2006-09-14 2013-11-19 Closureturf Llc Cover system with gas collection system for waste sites and environmental closures
US20120063854A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic ground cover system for erosion protection for use with or without a sand/soil ballast
US20120064262A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic grass cover for mse walls

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD667228S1 (en) * 2009-09-24 2012-09-18 Yuyama Manufacturing Co., Ltd. Sheet for a drug bag
US9587367B2 (en) * 2010-09-13 2017-03-07 Closureturf, Llc Synthetic grass cover for MSE walls
US20120064262A1 (en) * 2010-09-13 2012-03-15 Michael Ayers Synthetic grass cover for mse walls
WO2015050828A2 (en) 2013-09-26 2015-04-09 Watershed Geosynthetics Llc Earthwork basket with synthetic turf facing
WO2015053977A1 (en) 2013-10-10 2015-04-16 Watershed Geosynthetics Llc Formed in place filled structure with synthetic turf
US11045847B2 (en) 2013-10-29 2021-06-29 Watershed Geosynthetics Llc Geocomposite covering
WO2015126996A1 (en) * 2014-02-21 2015-08-27 Watershed Geosynthetics Llc Synthetic ground cover system for erosion control
US10465316B2 (en) 2015-08-20 2019-11-05 Glen Raven, Inc. Outdoor fabric
US10058904B2 (en) 2016-03-08 2018-08-28 Commercial Liability Partners, Llc Waste disposal closure system
US10343198B2 (en) 2016-03-08 2019-07-09 Commercial Liability Partners, Llc Waste disposal closure system
US20210292979A1 (en) * 2016-03-17 2021-09-23 Watershed Geosynthetic LLC Ballast System For Roof Protection
US10582697B2 (en) 2016-07-26 2020-03-10 Curio Holding Company Olfactory mat for domestic animals
US11540491B2 (en) 2016-07-26 2023-01-03 Curio Holding Company Olfactory mat for domestic animals
USD818206S1 (en) 2016-09-30 2018-05-15 Clear-Coat Holding Company Olfactory mat structure for an olfactory mat for domestic animals
USD890444S1 (en) 2016-09-30 2020-07-14 Curio Holding Company Olfactory mat for domestic animals
US11277091B2 (en) 2017-06-20 2022-03-15 Watershed Solar LLC Integrated photovoltaic module mounting system for use with tufted geosynthetics
WO2019108687A1 (en) * 2017-11-28 2019-06-06 Watershed Geosynthetics Llc Water flow control ground cover
US20190161931A1 (en) * 2017-11-28 2019-05-30 Watershed Geosynthetics Llc Water flow control ground cover
WO2020047533A1 (en) * 2018-08-31 2020-03-05 Watershed Geosynthetics Llc Tufted geotetxtile with increased shear resistance to hydraulic infill displacment and dry-flow loading
US20230193567A1 (en) * 2018-08-31 2023-06-22 Watershed Geosynthetics Llc Tufted Geotextile With Increased Shear Resistance To Hydraulic Infill Displacement And Dry-Flow Loading
US20210141121A1 (en) * 2019-11-13 2021-05-13 Jiangxi Academy Of Environmental Sciences Structure and method for three-dimensional restoration of slope soil in abandoned ion-absorbed rare earth mining area
US11591765B2 (en) * 2019-11-13 2023-02-28 Jiangxi Academy Of Environmental Sciences Structure and method for three-dimensional restoration of slope soil in abandoned ion-absorbed rare earth mining area
CN110835877A (zh) * 2019-11-15 2020-02-25 湖北绿城体育产业有限公司 一种改良热熔型环保人造草及其制作方法
CN111424687A (zh) * 2020-04-20 2020-07-17 中国科学院地质与地球物理研究所 一种利用磷石膏与微生物矿化技术用于膨胀土边坡生态防护的施工方法

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Publication number Publication date
CA2811283C (en) 2018-01-02
US20150252525A1 (en) 2015-09-10
EP2616193A2 (en) 2013-07-24
WO2012037152A3 (en) 2013-09-26
EP2616193B1 (en) 2020-12-16
ES2854844T3 (es) 2021-09-23
CA2811283A1 (en) 2012-03-22
PT2616193T (pt) 2021-03-04
WO2012037152A2 (en) 2012-03-22
PL2616193T3 (pl) 2021-06-28
DK2616193T3 (da) 2021-03-01
HUE054056T2 (hu) 2021-08-30
MX2013002811A (es) 2013-08-01
MX337462B (es) 2016-03-03

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