BIODEGRADABLE WOVEN BURLAP SILT FENCE FOR TRENCHLESS AND TRENCH INSTALATION AND METHOD OF INSTALLING THE SAME

Abstract

A cost effective, efficient, and easy to implement biodegradable woven composite burlap silt fences with stabilizing fins having a bury depth indicator. The silt fence comprises plurality of spaced stakes; and a burlap geotextile with a weight greater than 15 oz per square yard and less than 50 oz per square yard comprising one of i) a single layer burlap material and ii) a composite burlap material having multiple burlap layers. A trenchless method of installation includes using an apron on a lower portion of the geotextile and driving the plurality of spaced wooded or metal stakes into the ground until the integral ground engaging apron is flush with the ground; and staking the ground engaging apron to the ground with staking elements.

Claims

1. A silt fence comprising: A plurality of spaced stakes; and A burlap geotextile with a weight greater than 15 oz per square yard and less than 50 oz per square yard comprising one of i) a single layer burlap material and ii) a composite burlap material having multiple burlap layers.

2. The silt fence according to claim 1, further including a belting strip folded over the top of the bulap geotextile and secured thereto.

3. The silt fence according to claim 2, wherein the belting strip is a 4 wide burlap strip sewn to the geotextile.

4. The silt fence according to claim 2, further including stabilizing fins on selective stakes formed by a plate secured thereto.

5. The silt fence according to claim 4, wherein in the burlap geotextile is a single layer burlap material formed of 17 oz burlap.

6. The silt fence according to claim 4, wherein in the burlap geotextile is an asymmetrical biodegradable composite burlap geotextile.

7. A trenchless method of installing a silt fence for erosion, sediment and pollution control, comprising the steps of: Providing a silt fence bundle comprising a plurality of spaced wooded or metal stakes and a burlap geotextile with a weight greater than 15 oz per square yard and less than 50 oz per square yard comprising one of i) a single layer burlap material and ii) a composite burlap material having multiple burlap layers, with the geotextile coupled to the spaced wooded or metal stakes and including an integral ground engaging apron; Driving the plurality of spaced wooded or metal stakes into the ground until the integral ground engaging apron is flush with the ground; and Staking the ground engaging apron to the ground with staking elements.

8. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 7, wherein the silt fence bundle further includes a belting strip folded over the top of the bulap geotextile and secured thereto.

9. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 8, wherein the belting strip is a 4 wide burlap strip sewn to the geotextile.

10. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 8, further including stabilizing fins on selective stakes formed by a plate secured thereto.

11. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 10, wherein in the burlap geotextile is a single layer burlap material formed of 17 oz burlap.

12. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 10, wherein in the burlap geotextile is an asymmetrical biodegradable composite burlap geotextile.

13. The trenchless method of installing a silt fence for erosion, sediment and pollution control according to claim 7, wherein the staking elements include staples and wherein the staples include a row of staples at a leading end of the apron located at a distal end of the fabric.

14. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 13, wherein in the burlap geotextile is a single layer burlap material formed of 17 oz burlap.

15. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 13, wherein the silt fence bundle further includes a belting strip folded over the top of the bulap geotextile and secured thereto.

16. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 15, wherein the belting strip is a 4 wide burlap strip sewn to the geotextile.

17. The trenchless method of installing a silt fence for erosion, sediment and pollution control, according to claim 16, further including stabilizing fins on selective stakes formed by a plate secured thereto.

18. A silt fence configured for trenchless installation comprising: A plurality of spaced stakes; and A single layer burlap geotextile with a weight greater than 15 oz per square yard and less than 50 oz per square yard and including an integral ground engaging apron.

19. The silt fence according to claim 18 further including a belting strip formed as a 4 wide burlap strip folded over a top of the geotextile and sewn to the geotextile.

20. The silt fence according to claim 19, further including wooden stabilizing fins on selective stakes formed by a triangular plywood plate secured thereto.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 is a perspective schematic view of a prior art trenched silt fence.

[0020] FIG. 2 is an elevated schematic view of a biodegradable woven composite silt fence with trench engaging stabilizing fins having a bury depth indicator according to one embodiment of the invention.

[0021] FIG. 3 is a rear perspective schematic view of biodegradable woven composite silt fence with trench engaging stabilizing fins having a bury depth indicator according to FIG. 2.

[0022] FIG. 4 is an enlarged schematic elevated side view of a bottom of the biodegradable woven composite silt fence of FIG. 2.

[0023] FIG. 5 is an enlarged schematic elevated side view of a bottom of the biodegradable woven composite silt fence of FIG. 2 in an alternative apron and bury configuration.

[0024] FIGS. 6 and 7 are schematic perspective views of a single layer biodegradable woven silt fence in a trenchless installation with stabilizing fins having a bury depth indicator according to one embodiment of the invention.

[0025] FIG. 8 is a perspective schematic view of an inside corner formed with the trenchless installation method according to one embodiment of the present invention.

[0026] FIG. 9 is an elevated plan view of a 50 pre-staked bundle of a geotextile silt fence and 5 stakes according to one embodiment of the invention.

[0027] FIG. 10 is a plan view of a chiseled tip on a plate body for providing side fins for the stakes of the silt fence of the invention that are to be driven into the ground.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present invention is directed to a single layer biodegradable woven composite silt fence 110 shown in FIGS. 6-9 or biodegradable woven composite silt fence 10, shown in FIGS. 2 to 5. The biodegradable woven composite silt fence 10 is shown with trench engaging stabilizing fins 40 having a bury depth indicator 42. The silt fence 10 will include a composite woven geotextile 20 coupled to stakes 30 by staples 32 or the like provided at 4 intervals. The silt fence 110 will include a single layer woven geotextile 120 coupled to stakes 130 by staples 132 or the like provided at 4 intervals.

Composite Woven Geotextile 20 of Silt Fence 10

[0029] The woven geotextile 20 is asymmetrical burlap composite. Composite within the meaning of this application defines multiple layers to the geotextile 20 across its operative surface, with each layer formed of woven burlap material (such as three leading burlap layers 22 and two trailing burlap layers 24). Woven defines fabrics formed of interlaced threads. Woven burlap fabric is fabric woven from vegetable fibers such as jute, hemp, sisal, or similar natural fibers.

[0030] Burlap fabric, also known as Hessian fabric, or Crocus fabric in the Caribbean, is generally considered dense woven fabric, historically coarse, more recently produced in a more refined state, the refined version is sometimes known simply as jute, and is well established as an eco-friendly material. Burlap comes in different types, weights or grades and colors. Color is not critical for the woven geotextile 20 other than possibly to increase visibility of the silt fence 10 minimizing the likelihood of people (i.e. construction workers on construction equipment) accidently damaging the silt fence 10, but cost is a critical factor in having users adopt the silt fence 10. The grade or weight of burlap for the layers 22 and 24 forming the asymmetrical burlap woven geotextile 20 is important in the silt fence 10. Conventional burlap fabric comes in different weights ranging from 5 to 11 oz (generally measured as weight/square yard). The higher the weight, the tighter the weave. The preferred embodiment of the invention uses a woven geotextile 20 formed of three 7 oz burlap layers 22 on the leading or upstream side (i.e. facing the flow of water) and two 10 oz burlap layers 24 on the trailing or downstream side.

[0031] The composite geotextile 20 is considered asymmetrical because the layers (three 7 oz layers 22 and two 10 oz layers 10) are arranged asymmetrically along the flow path. A symmetrical arrangement would have, for example, all the same weights for the layers, or the same weight for the leading one or two layers as the last one or two layers, or could be a single layer and be symmetrical.

[0032] Without being limited by theory, the initial layers 22 serve effectively as a pre-filter with the central core of a 7 oz layer 22 and a 10 oz layer 24. The outer layers also serve to protect the core without detrimentally inhibiting flow characteristics of the geotextile 20. The five layer structure allows for a controlled deterioration or degradation of the geotextile 20 in the field without hindering performance.

[0033] The layers 22 and 24 of the composite geotextile 20 may be treated such as with animal fat to improve lifespan and performance of the geotextile. Other ecologically friendly treatment materials may be used such as vegetable oils or lanolin. It is desirable that the surface treatment for the layers 22 and 24, if any, be ecologically friendly.

Woven Geotextile 120 of Silt Fence 110

[0034] The woven geotextile 120 is a single layer burlap material. Single layer within the meaning of this application defines only a single layer to the geotextile 120 substantially across its operative surface. In other words the inclusion of belting 160 at the top does not transform the single layer 120 into a composite component for a silt fence. The single layer of geotextile 120 is formed of woven burlap material. Woven defines fabrics formed of interlaced threads. Woven burlap fabric is fabric woven from vegetable fibers such as jute, hemp, sisal, or similar natural fibers. As noted above, burlap comes in different types weights or grades and colors. Color is not critical for the woven geotextile 120 other than possibly to increase visibility of the silt fence 110 minimizing the likelihood of people (i.e. construction workers on construction equipment) accidently damaging the silt fence 110, but cost is a critical factor in having users adopt the silt fence 110.

[0035] The grade or weight of burlap forming the woven geotextile 120 is important in the silt fence 110. As noted above, conventional burlap fabric comes in different weights ranging from 5 to 11 oz. (generally measured as weight/square yard). The preferred embodiment of the invention uses a woven geotextile 120 formed of 17 oz sagless burlap It is well known that to utilize 17 oz sagless burlap in upholstery applications and in upscale furniture design.

[0036] The surfaces of the geotextile 120 may be treated such as with animal fat to improve lifespan and performance of the geotextile. Other ecologically friendly treatment materials may be used such as vegetable oils or lanolin. It is desirable that the surface of the geotextile 120, if any, be ecologically friendly.

Belting 60 and 160

[0037] A belting and visibility strip 60 formed by a 4 wide strip of natural fiber material folded over the top of the geotextile 20 and sewn thereto may be used as reinforcing belting for the fence 10. The strip 60 serves as a reinforcing member, an aid in geotextile assembly, and a visual indicator of the top of the fence 10. If the strip 60 is made from a high visibility color, such as yellow or red or neon green or the like, it will add another safety feature minimizing the accidental interference with the silt fence 10 during construction activities (e.g., accidentally running over the fence 10 with construction equipment, or placing stored construction materials on the fence 10). The minimization of the accidental knocking down of the silt fence 10 can also be broadly categorized as improving the operation of the fence 10.

[0038] Fence 110 includes a belting strip 160 formed by a 4 wide burlap strip folded over the top of the single layer geotextile 120 and sewn thereto. The burlap strip 160 serves as a reinforcing member, and a visual indicator of the top of the fence 110. If the burlap strip 160 is made from a high visibility color, such as yellow or red or neon green or the like, it will add another safety feature minimizing the accidental interference with the silt fence 110 during construction activities as detailed above.

Stabilizing Fins 40 and 140

[0039] The woven geotextile silt fence 10 further includes trench engaging stabilizing fins 40 formed by wooden plate with a bury depth indicator 42 at a top thereof. The stabilizing fins 40 are easily formed by attaching a wooden rectangular plate body to selective, possibly all, stakes 30 opposite the side coupled to the woven geotextile 20. The length of the wooden plate body forming fins 40 is preferably less than the depth of a conventional silt fence trench 52 in the ground 50 and the width is less than 2 times the width of the stake 30, preferably about 1.9 times the width of the stake 30. The fins 40 are the portion of the body of the plate extending beyond the stake 30. This size makes the fins 40 effective but not unwieldy or costly. The plate body forming fins 40 will engage the wall of the trench 52 during installation and the fins 40 will add a stabilizing resistance preventing the fence 10 and stakes 30 from being pushed over and out of position by ponding water and the like on the fabric 20 or on the fence 10 as a whole.

[0040] In addition to the stabilizing fins 40, the top horizontal surface 42 of the plate body forming fins 40 acts as a visual bury depth indicator 42 for the stake 30. Users can quickly visually see how far to position the stake 30 in the ground 50, namely when the top surface 42 of the plate body forming fins 40 (also the top surface of the fins 40) is even with the top of the ground in the trench 52. As the fins 40 is less than the depth of the trench 52, the plate body forming fins 40 does not increase insertion resistance for the stake 30, and a rectangular shape for the plate body forming fins 40 is effective without causing other detrimental problems. The body forming fins 40 for fence 10 may be made of metal or wood to be ecologically friendly (by avoiding plastic), but wood may be most cost effective.

[0041] The single layer woven geotextile silt fence 110 further includes stabilizing fins 140 formed by triangular wooden plywood plate (- thick generally) with a bury depth indicator 142 at a top thereof shown in FIG. 10. The stabilizing fins 140 are easily formed by attaching the wooden triangular plate body to selective, possibly all, stakes 130 opposite the side coupled to the single layer woven burlap geotextile 120. The length of the triangular wooden plate body forming fins 140 is preferably less than the depth stake 130 and the width is less than 2 times the width of the stake 130, preferably about 1.9 times the width of the stake 130. The fins 140 are the portion of the body of the triangular plate extending beyond the stake 130. This size makes the fins 140 effective but not unwieldy or costly.

[0042] The single layer woven geotextile silt fence 110 is configured for trenchless installation whereby the stakes 130 are typically driven into the ground and the triangular plate body forming fins 140 is shaped to easily penetrate the ground during installation and the fins 140 will add a stabilizing resistance preventing the fence 110 and stakes 130 from being pushed over and out of position by ponding water and the like on the fabric 120 or on the fence 110 as a whole.

[0043] In addition to the stabilizing fins 140, the top horizontal surface 142 of the triangular plate body forming fins 140 acts as a visual bury depth indicator 142 for the stake 130. Users can quickly visually see how far to drive the stake 130 in the ground 50, namely when the top surface 142 of the triangular plate body forming fins 140 (also the top surface of the fins 140) is even with the top of the ground 50.

Stakes 30 and 130

[0044] The stakes 30 and 130 for fences 10 and 110, respectively, may be made of wood or metal, but wood is deemed most cost effective. The plate body forming fins 40 may be nailed or otherwise attached to the individual stakes 30. Metal staples 32 are shown coupling the geotextile 20 to the stakes 30 and are shown angled to minimize tearing of the fabric 20.

Trench or Trenchless Installation

[0045] The multi-layer structure of the composite geotextile 20 allows for the silt fence to be used in a conventional bury mode (trench mode), as shown, with about 12 of the geotextile 20 below grade in trench 52. Some applications desire the fence 10 to be installed in a trenchless configuration or apron mode (not shown) analogous to the trenchless implementation preferred for fence 110 described below in which the otherwise buried portion of the geotextile 20 is laid on the ground facing the flow of water and preferably secured to the ground, such as with staples. The multi-layered structure of the geotextile 20 allows for the fence 10 to be implemented simultaneously in both a trench mode and an apron mode as shown in FIG. 5. In this apron and bury mode the leading layers 22 of the fence 10 are used as an apron on top of the ground (preferably secured by staples) while the trailing two layers 24 are in bury or trench mode. An attaching line of stitching at a bury or apron line (e.g. 12 up from the bottom) is helpful to allow for this installation. The trench and apron mode of FIG. 5 is a subset of a trench installation as the trench must still be formed.

[0046] The height of the geotextile 20 above the grade is 18-28 (without fence backing), preferably 24 with 12 inches as below grade for bury or on grade apron or both as shown. The geotextile could extend to 36 above grade if coupled with a reinforced backing, typically a chain fence, but the 18-28 is preferable.

[0047] One of the main purposes of any silt fence is to prevent the unwanted migration of disturbed soil during construction. The trench 52 that buries the lower part of the fabric 20 of the fence 10 is utilized to prevent water creating a path under the fence 10 bypassing the fabric 20. However, this installation process creates extra disturbed soil that adds to the disturbed soil load of the fence 10. More significantly, this installation requires trenching tools and labor.

[0048] FIGS. 6-10 show a trenchless installation of the fence 110 that minimizes the installation time and soil disturbance without effecting operation of the fence 110. There are several advantages to the trenchless installation shown in FIGS. 6-10. The first is the equipment needed to install the fence 110 is merely sledgehammer, utility knife, and staple guns for staples 132 (or tool for wire ties if used) and apron staples 182, 184 and 186 (discussed below). There is no trenching equipment required or disturbed soil.

[0049] In the trenchless installation the stakes 130 are driven into the ground with a sledge hammer, and as shown in FIGS. 6-7 the top surface 42 of the plate bodies can also be used as a depth of driving guide. The plates may be positioned without the top surface 42 forming a guide so as to be completely buried as shown in FIG. 7. In this method of installation the plate is preferably beveled on the bottom (triangular in shape) as the stakes 130 will be driven into the soil 50. A preferred shape for plates when the stakes are driven into the ground such as in a trenchless installation is shown in FIG. 10. The plate still provides stabilizing fins 140 for the fence 10. FIGS. 6-9 shows preferred wooded stakes 130 with preferred staples 32 as fasters, while FIG. 9 shows the use of metal t-posts forming stakes 130 and wire ties for fasteners 32.

[0050] With the stakes 130 driven into the ground 50, the lower portion 121 forms a ground engaging apron that is secured to the ground through staking elements 182, 184 and 186. The plurality of spaced wooded or metal stakes 130 are driven into the ground until the integral ground engaging apron 121 is flush with the ground 50. Preferably the staking elements 182, 184 and 186 are 16 staples. The apron 121 is preferable about 12 in length. The staking elements 182, 184 and 186 include a line of staples 182 evenly spaced along the leading edge (the distal edge of the fabric 120) of the apron 121 with about 6 proving to be an effective distance. The distal end of the fabric 120 is the end spaced from the top coupling strip 160, which is considered the leading end of the apron 121 as it faces the upstream side of ground 50. The staking elements 182, 184 and 186 include a groupings of about four staples 184 evenly spaced along the trailing edge of the apron 121. The trailing edge of the apron 121 is spaced about 12 up from the distal end of the fabric 120, and about 6 between the staples 184 in the grouping proving to be an effective distance and the grouping being centered between the stakes 130. The staples 182 and 184 are preferably positioned perpendicular to the line of the fence 10 whereby the head of the staples extend generally perpendicular to the plane of the upper portion of the fabric 120 on the stakes 130.

[0051] The staking elements 182, 184 and 186 include a groupings staples 86 spaced along overlapping portions of apron 121. FIG. 8 is a perspective schematic view of an inside corner of the fence 110 formed with the trenchless installation method according to one embodiment of the present invention. The user cuts the apron 121 at 123 and overlaps the apron in the inside corner and adds staples 186 to hold down the overlapped portion. FIG. 9 is an elevated plan view of a 50 pre-staked bundle of a geotextile silt fence 110 with stabilizing features and 5 stakes according to one embodiment of the invention showing a flap 125 on one edge of the bundle. When adding a second bundle for a fence installation the flap 125 of one section is overlapped with the other end (stake 130 without plate 140) and the a grouping of staking elements 186 will be used in the overlapped portion. Further the upper portion of the flap can be coupled to the end stake of the adjacent bundle via staples 132 (generally 1).

[0052] The single layer 17 oz sagless burlap fabric 120 of the fence 110 is particularly well suited for trenchless installation but this method may be applicable to other silt fences assuming they can achieve a solid engagement with the ground and prevent water from undercutting beneath the fence 110.

[0053] The use of metal posts for stakes 130 is well suited for an alternative trenchless installation in which the unbundled metal stakes 130 (no fabric 120 yet attached) are driven into the ground and the fabric 120 with apron 121 is later attached to the stakes 130 in situ with ties as fasteners 132 and the apron 121 is secured to the ground 50 staking elements 182, 184 and 186 as discussed above. The in situ installation may also be used with wooden stakes 130.

Fence Design

[0054] In the silt fence 10 as shown, above grade, the three 7-ounce layers 22 facing the water are more open and form a lofted/thicker/fuzzy pre-filter to entangle and collect solids before getting to the tighter 10 ounce layers 24 in the back. This feature gets better over time because the looser weave 7 ounce burlap layer 22 fibrillates (gets fuzzy) over time as it wets and dries. This helps with pre-collecting solids and should enable better blinding resistance at the 10 ounce layers 24. Further, it's better to have the stronger textile (e.g., 10 ounce layers 24) in the back to resist the bulge/push. This concept may be referenced as collective resistance and has been used in other silt fences using a scrim backer.

[0055] The silt fence 10, primarily below the grade in trench installations, is designed to fight rot from the outside in as it is expected that the outer layers will rot first. Over time, it is expected that that the inner 10 ounce layer 24 and the inner 7 ounce layer 22 next to it to be the last strength survivors. Once below grade fully rots, the geotextile 20 will likely tear at the bury line and effectiveness of the fence 10 is largely finished. The silt fence 10 is designed to resist that for as long as possible and the fence 10 as described and shown is expected to be at least 9 to 12 months in the field.

[0056] Regarding weight, the geotextiles 20 and 120 of the silt fences 10 and 110 needs to be under 50 ounces per square yard, preferably less than 45 ounces per square yard. The geotextiles 20 and 120 have a weight greater than 15 oz per square yard. The fence 10 as shown and described has a geotextile about 41 ounces per sq yard (three 7 ounce layers 22 plus two 10 ounce layers 24) and the fence 110 has a geotextile about 17 ounces per sq yard. With a textile 20 of 36-inch tall, for the fence 10 that's about 13-14 ounces a linear foot of fence 10. Exceeding these upper weights makes the resulting fence 10 or 110 generally nonviable with too much sagging. The asymmetric design of the geotextile 20 of the fence 10 and the single layer geotextile of fence 110 addresses weight advantageously.

[0057] It is apparent that many variations to the present invention may be made without departing from the spirit and scope of the invention. The present invention is defined by the appended claims and equivalents thereto.