Plate System For Sand Boil Mitigation

This invention relates in general to a laminated support mat. In particular, this invention relates to embodiments of an improved plate system that comprises a plurality of reinforced laminated support mats and is configured for placement over a sand boil.

The construction industry uses solid sawn wood and wood panel members in a variety of forms to aid in the erection of buildings, roads, and bridges. For example, temporary road panels and crane mats are often constructed using solid-sawn hardwood timbers or some species of softwoods. These panels are used to form a temporary lightweight roadway or foundation to facilitate vehicular and equipment travel as may be required in construction operations. Other industry users of such mats include users in the field of pipeline, utility, transportation, oil, and infrastructure.

As shown in, a conventional road panel, shown generally at, is formed by using a plurality of solid sawn timber elements. Typically, four pieces of solid sawn timberare used, each having a cross-sectional dimension ranging from about 8 inches by 8 inches to about 12 inches by 12 inches, with a length of 16 feet. The four pieces of timberare usually bolted together using boltsto form the temporary road panelhaving an assembled dimension of 4 feet by 1 foot by 16 feet. Several panels may be placed side by side over existing ground to form a temporary roadway or to support cranes on a construction site. Ground conditions under the panels vary greatly and may include, for example, sand, clay, wetlands, and possibly a considerable amount of water. Another conventional wood mat uses smaller dimensional lumber and uses nails, carriage bolts, or steel rods as a fastening system. All of these systems have mechanical fastening systems to transfer stresses between components. Additionally, U.S. Pat. No. 4,932,198 discloses a compound timber-metal stressed deck with metal plates inserted between the timbers.

Some support mats may be reinforced with steel or other metal beams. U.S. Pat. No. 8,906,480 discloses one such reinforced laminated support mat.

A sand boil, also known as a levee boil, is a destructive phenomenon that can occur when water builds up against an earthen levee for a long time, causing groundwater to push upward on the land inside the levee. This pressure can force groundwater through the levee's underside to the surface, sometimes appearing to bubble or boil. Sand boils can happen during high water or when seepage occurs and can develop anytime the river level is high.

When flood waters remain high for a long time though, under-seepage can increase in volume and velocity and begin the destructive process of moving sand and other alluvial material from the levee foundation, through the ground, to the surface, forming the sand boils. Left unchecked, the process of forming sand boils may eventually lead to levee failure.

To mitigate the negative effect of sand boils during a flood, engineers will typically build a ring of sandbags around the sand boil. The sandbag ring is built higher and higher, until the weight of the water inside the ring slows the water flow from the boil to where there is just clear water coming from the sand boil. The weight of the water inside the ring of sandbags may also stop the water flow from the boil. The persons building the ring of sandbags, however, are required to work in an area that will be quickly flooded should the levee fail.illustrate the formation of a sand boil and the subsequent resulting levee failure. For example,illustrates a leveeadjacent a body of water, such as a riverand shows seepagefrom the riverthat forms a sand boil SB, and the initial formation of a pipe.and show continued seepage, causing backward erosion and the lengthening of the pipe.shows widening of the pipe, which leads to levee failure, as shown in, and subsequent levee breach, as shown in.

Thus, it would be desirable to provide an improved plate system configured for placement over a sand boil, and further configured to slow or prevent the flow of sand and other alluvial material from the levee foundation, and therefore to prevent levee failure.

This invention relates to an improved sand boil mitigation pad that has a first layer including a plurality of laminated support mats nested and attached together, and defining a deck. The sand boil mitigation pad may include a second layer that includes a plurality of the laminated support mats configured as runners, wherein the runners are positioned perpendicular to the laminated support mats of the deck and are attached thereto, and wherein adjacent ones of the runners are spaced apart. The sand boil mitigation pad may further include a third layer that includes a plurality of the laminated support mats configured as bars, wherein the bars are positioned perpendicular to the runners, and wherein at least two of the bars are attached to one or both of the runners and the deck.

Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in view of the accompanying drawings.

The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

illustrates a known reinforced laminated support mat. The illustrated reinforced laminated support matis comprised of a plurality of laminated beams or billets, has a substantially planar wide or load-bearing face, two opposing, longitudinally extending, edges, a length L of about 14 ft, and a width W. Non-limiting examples of suitable mat widths W include widths of 4 feet and 8 feet. It will be understood however, that the reinforced laminated support matmay have any other desired length.

Each of the illustrated billetscomprises a plurality of wood members or individual wood laminations. Aperturesmay be formed through the reinforced laminated support matfor receiving fastening means, such as substantially rigid fasteners or threaded steel rodsattached with nuts.

In the illustrated embodiment, a plurality of resilient spacersare shown disposed within the space between adjacent billets. It will be understood that any number of resilient spacersmay be disposed within the space between adjacent billets. The resilient spacersmay be formed from any desired material having the properties of good mechanical strength, high ozone and weather resistance, good aging resistance, low flammability, good resistance toward chemicals, moderate oil and fuel resistance, and adhesion to many substrates, such as for example rubber and styrene-butadiene rubber (SBR).

As used in the description of the invention, the term “mat” includes mats as well as panels. Examples of such a support mat are described in co-assigned U.S. Pat. Nos. 7,137,236 and 7,818,929, herein incorporated by reference in their entirety.

The reinforced laminated support matincludes a plurality of elongated, protective edge membersand. Each illustrated protective edge memberis formed of steel having a corrugated shape and attached to each of the longitudinally extending edges. The corrugated protective edge membersinclude apertures through which the steel rodsextend for attachment to the reinforced laminated support mat. The corrugated protective edge membersare similar to the corrugated protective edge members, however distal ends of the corrugated protective edge memberspositioned at the distal ends of the reinforced laminated support matinclude a corrugated sectionhaving a width about ½ the width of the other corrugated sections in the corrugated protective edge members, and in the corrugated protective edge members. The corrugated sectionincludes an attachment flangehaving an aperture formed therethrough. A lag boltextends through the aperture in the attachment flangeand into the billetof the reinforced laminated support mat.

When two or more of the reinforced laminated support matsare used together in the field, they are typically positioned side by side such that the corrugations of the corrugated protective edge membersandare nested.

Referring now to, an improved plate system is configured as a multi-layered pad, shown generally at. The padcomprises a plurality of the reinforced laminated support matsand is further configured for placement over a sand boil SB, such as a sand boil SB having a diameter D of about 6 ft.

The illustrated plate system or padincludes a first layer or deck, and a second layerthat comprises a plurality of the laminated support matsconfigured as runners. The deckincludes a plurality of the laminated support matsnested together as shown in, and attached together, by attachment means, such as with hooks and chains, as shown in. The runnersare positioned perpendicular to the laminated support matsof the deck, are attached thereto, and adjacent ones of the runnersare spaced apart.

Significantly, the interconnectivity of the matsin the deckis key to the assembly of a functional pad. It is this structural connection, such as shown in, that prevent the matsfrom separating, and forces the connected matsto perform as a contiguous plate system or pad. For example, a collection of conventional timber mats laid similarly would separate under the flow of water from a sand boil and alter the physics of the resistance equation.

As shown in, a portion of a sand boil mitigation padis shown having a means of connecting the reinforced laminated support matsin adjacent layers of the sand boil mitigation pad, such as connecting the runnersto the deck, and connecting the barsto the runners. In the illustrated embodiment, the means of connecting the reinforced laminated support matsis configured as a chain and hook assemblyhaving a chainand chain hooksat each end thereof. As shown, the links of the chainpass downwardly through an opening between the edge of the matand the corrugated steel protective edge membersof the upper layer of mats, such as, for example, the runners, and then up and through the bottom of an opening between the edge of the matand the corrugated steel protective edge membersof the lower layer of mats, such as, for example, the deck. A throat of each hookis positioned, or hung on an edge of the corrugated steel protective edge membersof the matsin the respective upper and lower layers of the sand boil mitigation pad, such that the hookswill not become dislodged due to the force of gravity.

Similarly, as shown in, a portion of a sand boil mitigation padis shown having a means of connecting adjacent reinforced laminated support matsin one layer of the sand boil mitigation pad. In the illustrated embodiment, the means of connecting the adjacent reinforced laminated support matsis the chain and hook assembly. As shown, the links of the chainpass downwardly through an opening between the edge of the matand the corrugated steel protective edge membersof one of the two adjacent mats, and then up and through the bottom of an opening between the edge of the matand the corrugated steel protective edge membersof a second of the two adjacent mats. The throat of each hookis positioned, or hung on an edge of the corrugated steel protective edge membersin each of the respective adjacent matsof the sand boil mitigation pad, such that the hookswill not become dislodged due to the force of gravity.

A third layerthat comprises a plurality of the laminated support matsconfigured as bars. The barsare positioned perpendicular to the runners. In the illustrated embodiment, two of the barsare positioned at outboard edges of the padand are attached to the runnersand may be attached to the deck. It will be understood however, that the barsmay be positioned at any desired location on the runners, and that the padmay include more than two of the bars. As shown in, the padis about 40 ft×40 ft and is configured for placement over a sand boil SB having a diameter of about 6 ft.

Although illustrated as having three layers comprising a deck, runners, and bars, it will be understood that the padmay have other configurations. Other configurations of the padinclude, but are not limited to, a padhaving just a single deck, a padhaving two decksand one layer of runners, and a padhaving three decks, one layer of runners, and one layer of bars. The specific configuration of the padwill be determined based on the physics of the sand boil SB, including, but not limited to, its water pressure and diameter. [other configurations??]

Advantageously, the padmay be formed having any desired dimensions, including, but not limited to 100 ft×200 ft. In the event of flooding in a river adjacent to a levee, an area of potential seepage may be identified. However, the area of potential seepage may be quite large, and a large pad, such as a pad having dimensions of about 100 ft×200 ft may be deployed.

Referring again to, and to, unlike the known panel, the padincludes openings or perforations, including longitudinal openingsbetween adjacent billets, i.e., the space created by the resilient spacers, and longitudinal openingsbetween adjacent mats.

Thus, the padmay be placed in a location where sand boils SB may form, or the padmay be placed over a sand boil SB that has already formed. When placed over a sand boil SB, the padis configured to mitigate the negative effect of the sand boil SB by reducing the discharge velocity of seepage water flowing to the sand boil SB such that most or all the alluvial material in the flowing water precipitates out of the seepage water flow before it reaches the sand boil SB throat. Advantageously, the padincludes defined void space, such as for example, the longitudinal openingsbetween adjacent billetsand the longitudinal openingsbetween adjacent mats. Counter pressure by the padto the head of the sand boil SB is sufficient to reduce the discharge velocity of the seepage water flow without completely restricting the overall flow of the seepage water.

The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.