US2876628A - Rapid sinking articulated revetment - Google Patents

Description

March 10, 1959 y G. F. DlxoN, .1R 2,876,628

' RAPID sINKNG ARTICULATED REvETMEN Filed July 2, 1956 1 3 Sheets-Sheet 1 INVENToR. 'eore Fzxan, J7: BY c,

March 10, 1959 G. F. DIXON, JR iff' l l2,876,628

v RAPID SINKING ARTICULATED REVETMNT Filed July 2, 1956l v v -3 Sheets-Sheet 3 F535. y EL 5 55 L-.- v mm1 INVEN TOR. I

United States Patent() RAPID SINKING ARTICULATED REVETMENT George F. Dixon, Jr., Kansas City, Mo. Application July 2, 1956, Serial No. 595,564

4 Claims. (Cl. 61-38) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

The present invention provides certain improvements in articulated revetment assemblies customarily referred to in the art as revetment mattresses which are employed widely for protection and stabilization of the banks of streams or the like which are subject to watererosion, such revetment mattresses being applied to shore lines for inhibiting scouring and erosion thereof by water currents and streams. Such revetment mattresses usually are composed of tlexibly interconnected reinforced concrete blocks of substantially standard size, a substantially standard number of such individual blocks being exibly interconnected along both longitudinal and transverse sides to form a complete mattress or revetment section which is placed by suitable launching means on an embankment or similar location which is subject to water erosion.

Such revetments are intended to be permanent installations. However, in service, many widely dilering conditions may be encountered, particularly from the aspects of widely differing volumes and current velocities obtained in periods of floods or droughts, which may result in disarrangement of revetment mattresses which have already been launched in service locations, or variable current conditions may impede or prevent proper launching of such mattresses in desired location. Also, under service conditions the revetments, even if placed properly initially, may become displaced or distorted from lifting and sub-revetment scouring of the stream bed, even though the revetments are intended to be selfaccommodating and self-adjusting to irregularities in` the stream bed or the embankment upon which such revetments have been placed.

The present improved revetment construction is ntended to provide a revetment mattress which will sink rapidly through a owing stream of water independently of the velocities of the currents or moving volumes of water at the time of, launching, so that the revetment mattresses may be launched readily in desired locations, and which, because of structural features which will be referred to in greater detail hereinafter, will become increasingly more firmly anchored in position during service through the provision of means enhancing deposition and collection of stream-borne silt and detritus in and on the revetment mattresses during service by interrupting smoothly-flowing silt-bearing water currents in such manner that smooth flows will be braked and retarded as to their velocities with accompanying increased rate of sedimentation into and about the individual units of the placed revetments.

This feature of increasingly rm anchorage is found to inhibit the leaching of river banks and bed materials through the interstices of emplaced revetment mattresses, which leaching or scouring is a frequent cause of revetment failures. In addition to structural means in the revetment mattresses for enhancing sedimentation rates of Ysilt-bearing water `currents in Vand on the revetment,

Patented Mar. l0, 1959 lCC a the present invention includes provisions of means for accelerating the sinking of the revetment mattress through swiftly moving currents for enhancing accurate launching or placing of the revetment mattresses in desired locations.

At this point, it may be pointed out that in previous types and designs of articulated revetment mattresses for the protection and stabilization of stream banks and beds against erosion and scouring action by water currents and wave action, the interstices between individual blocks composing the mattresses either have been left open without particular provision for interruption of current ow along them, or closed almost completely by narrowing the interstices, such provisions, however, being found to have attendant disadvantages in practice, which are obviated by the improvements of the present invention.

The present invention is found to avoid the disadvantages revealed in use of prior types of revetments by providing suttcient openings to facilitate the sinking of the mattress, while at the same time the present improvements prevent leaching and scouring of river-bank and bed materials beneath the revetmen p In addition to the above-indicated advantages and objects of the present invention, a further object of the present invention is the provision of an articulated revetment mattress which inhibits scouring: and leaching of underlying river bed and bank materials, thus eliminating a common cause of revetment failures p A further object of the invention is to provide a revetment mattress which, although constructed `to prevent leaching along the interstices, still will have suicient open area in its body to permit it to sink freely into position despite high current velocities.

A still further object of the invention is to provide a revetment mattress having openings for relieving -or dissipatng uplift pressures beneath the mattress, thus permitting the mattress to be seated firmly on the bed or bank of a stream or river for enhancing the protective value of the mattress.

A further object of the invention is to provide an articulated revetment mattress provided with means for retarding or braking smoothly or evenly owing river currents along the exposed or upper surface of the installed revetment mattress for the purpose of augmenting deposition of silt or other materials carried by such currents in and on the revetment mattress for enhancing the protective value of the revetment by progressive increase in stability after launching. v

A still further object of the invention is to obtain maximum closing of interstitial spaces between individual blocks and still retain the flexibility requisite for self-l adjustment of the revetment mattress to the contours of the river bed by constructing the mattress so that all contiguously adjacent blocks within each mattress will have convex edges, thereby obtaining maximum practicable closing of such interstitial spaces while re taining flexibility between individual blocks.

A still further object of the invention is to prevent uninterrupted longitudinal ow of the stream along the interstices with attendant leaching of the stream bed, by constructing the mattress with interlocking edges between contiguous squares composing the mattress.

A still further and important object of the invention is to construct an articulated revetment mattress having sutlicient openings for assuring rapid sinking of the revetment in a rapidly moving stream or current by employing interlocking edges between the squares composing the mattress and employing conventional openings in the interstitial spaces between the individual units or blocks;r l

i or by providing additional openingsin the individual 3 with maximum closing of interstitial spaces between such individual units.

Further objects and advantages of the invention will become apparent as the description proceeds and the `features of novelty will be pointed out in particularity in the appended claims.

The invention will be understood more readily by reference to the accompanying drawings, in which* Fig. l is a fragmentary plan view of an illustrative form of a revetment mattress embodying certain of the improvements provided by the present invention;

Fig. 2 is a fragmentary plan view of a modiiied form of a revetment mattress, the View being generally similar to the showing of Fig. l;

Fig. 3 is a fragmentary plan view of a still further modified construction of a revetment mattress, the view being generally similar to Figs. l and 2 but showing a still further form of a revetment mattress including features of the present invention;

Fig. 4 is a vertical section taken on the line 4-4 of Fig. 1, looking in the direction of the arrows;

Fig. 5 is a vertical section taken on the line 5-5 of Fig. 2, looking in the direction of the arrows;

Fig. 6 is a vertical section taken on the line 6-6 of Fig. 3, looking in the direction of the arrows;

Fig. 7 is a vertical section taken on the line 7-7 of Fig. l, looking in the direction ofthe arrows, the View being taken at right angles to Fig. 4;

Fig. 8 is a vertical sectional view taken on the line 8-8 of Fig. 2, looking in the direction of the arrows, the view being taken at right angles to Fig. 5;

Fig. 9 is a vertical section along the line 9 9 of Fig. 3, looking in the direction of the arrows, the view being at right angles to Fig. 6;

Fig. 10 is a perspective view of two successive individualunits or slabs of the form shown in Fig. 1;

Fig. ll is a similar view with respect to Fig. 2; and

Fig. l2 is a similar view with respect to Fig. 3.

Referring more particularly to the drawings, and first to the embodiment of the improvements embodied in the form of revetment A shown in Figs. 1, 4, 7, and 10, a fragment of the revetment mattress A is illustrated as comprising an assembly of individual blocks or units 28 which usually are composed of concrete, which blocks are shown as being generally of rectangular peripheral shape with their longer sides extending transversely of the assembled mattress. In forming the articulated mattress of embodiment A, the individual blocks 28 are cast around a reinforcing fabric, such fabric being composed of corrosion-resisting metallic wire strands assembled into cables of suitable tensile strength, the views illustrating (a) the maximum closing of the straight interstices 20, with retention of free iiexibility between the individual blocks by use of convex contiguous longitudinal surfaces 32 for minimizing leaching action of stream currents on the river bed beneath the positioned revetment; and (b) the provision in each block of rows of recesses 26 which are aligned longitudinally and transversely with respect to each block and also the successive blocks. These recesses provide side walls 24 which are at least approximately normal to the plane of the top surface of the individual blocks, the recesses 26 extending from the top surface of the respective blocks to about the horizontal medial plane thereof, the sides of such recesses providing means for abruptly retarding or braking the velocity of ilow of smoothlyowing, silt-bearing water currents, which braking action produces a desired release of such silt from the currents, and deposition of released silt and detritus into the recesses or pockets 26 which retain the same and enhance the stability of placement of the revetment mattress through the increased weight of the mattress due to such accumulations. It will be noted, although this is not critical, that certain of the pockets 26 are substantially larger than others, and that the pockets are arranged so that `the pattern thereof is repeated in alternate blocks.

Thus it will be seen from Fig. 1 that in the central series of blocks, the first block is shown as having a row of large pockets or recesses intermediate two rows of small recesses, while in the second block of the series a row of the larger pockets parallels the top surface (or edge) of the block (viewed as in Fig. l), while there are two rows of the smaller pockets below the row of the larger pockets, the pocket-pattern of the first block being repeated in the third block of the row. This alternation of pocket-pattern appears in the blocks disposed on each side of the central series of blocks. It will be understood that such pockets extend inwardly from the top surface of each block when the revetment has been launched in protective position on a river bank or bed. In order to facilitate rapid sinking of the revetment during placement thereof into the desired site of its placement, the recesses or pockets 26 are provided with through-holes or openings 22 which extend from the bottoms of the recesses 26 for overcoming the buoyancy of the revetment in the water, resulting in a rapid sinking of the revetment responsively to the recesses 26 becoming filled with water. The sides 24 of the pockets or recesses 26 provide, in effect, vertical ribs or bales on the upper surface of the respective Iblocks, which sides or baflles retard flowing water currents adjacent to the placed revetment, the resulting obstructions causing deposition and collection of silt, mud, and other transported materials in the water currents until the pockets 26 become lilled therewith, thus progressively more firmly positioning the launched revetment in its desired position because of accumulating weight of the solid materials thus being collected.

As has been mentioned above, the individual blocks 20 of the revetment mattress are interconnected flexibly by reinforcing cables 30 which extend uninterruptedly throughout the length of the revetment mattress but transversely with respect to he individual blocks. There also are provided connecting cables 30 which take the form of endless loops and extend longitudinally through the blocks connecting successive pairs of blocks, these loops 30' extending beyond the ends of the successive pairs of blocks and being connected to launching cables 36 by clips 34.

A second embodiment B of the present improvements is shown in Figs. 2, 5, 8, and l1. This modification is generally similar to that of Figs. l, 4, 7, and 10, as described above, except that alternate blocks are molded so as to have equally spaced projecting or extending members 46 having spaces 40 therebetween, each block having two such projecting members or portions on one longitudinal side and three on the opposite longitudinal side, the projecting members 46 of one block complementarily intertting in the recesses 40 of the next adjacent block, forming a hinged interlit therewith. In a manner such as has been described above, the individual blocks 42 are cast around a reinforcing fabric composed of stranded cables 30 and 30', as aforesaid.

This embodiment of Figs. 2, 5, 8 and l1 illustrates maxi mum closing of interstices 40 and increased length thereof between interlocking extensions 46 of adjacent blocks 42 with a high degree of flexibility retained by the use of rounded or convex edges 32 on the individual blocks. Multiple holes 22 in the pockets or recesses 26 extending from the bottoms of the recesses through the remaining thickness of the blocks between the bottom of the recesses 26 and the bottom surface of each block, permit rapid ingress of water into the recesses or pockets 26 which are in the upper surface of the mattress when the revetment is in service, these holes 22 thereby facilitating rapid sinking of the revetment mattress during launching, as has been noted in connection with the foregoing described embodiment. Also, as lhas been described above, the vertical sides 24 of the recesses or pockets 26 are used as currentbraking or retarding means for impeding flow of continuously smoothly Viiowing stream currents along the revetment, thereby promoting ,deposition into the pockets ,26 of silt and other solids being conveyed by the stream currents, thereby increasingly firmly anchoring the revetment B into its launched location.

The individual blocks 42 are interconnected in the same manner as has been described in connection with the preceding embodiment, by cables 30 and 30', the latter being secured to launching cables 36 by clips 34, as described above in connection with the precedingly-described embodiment.

This second embodiment of the improved construction illustrates (a) the maximum closing of interstitial spaces between individual blocks of a row between interlocking extensions 46 of adjacent blocks 42, with a high degree of flexibility retained by the use of rounded or convex surfaces 32 on the individual blocks 42 within each mattress square; (b) the provision of holes 22 in the individual blocks 42 to give sufiicient open area to permit rapid sinking of the revetment in high velocities of stream currents; (c) the incorporation of the recesses 26 with vertical sides 24 to brake and to impede smooth high-velocity currents flo-wing along the exposed top surface of the mattress to produce filling of the pockets or recesses 26 with solid materials being carried by such currents, thereby enhancing permanence of placement of the launched revetments; and (d) the elimination of straight uninterrupted interstices along the line of flow by interlocking the adjacent extensions 46 of contiguous blocks 42.

A third illustrative embodiment C of the invention is illustrated in Figs. 3, 6, 9, and 12. In this modification C, the essential differences from the previously described embodiments A and B lie in the elimination of the holes through the bottom of the pockets and use of square longitudinal surfaces for the blocks instead of the previouslydescribed rounded surfaces. In this third embodiment C, the individual blocks or slabs 52 are cast around a reinforcing fabric composed of stranded cables 30, 30', as described above. The blocks 52 have sediment-collecting recesses or pockets 26 in their upper surface as aforesaid which have vertical walls 50 which brake and retard the velocity of flow of smoothly-fiowing water currents moving along the launched revetment, the baffle action of these walls or sides 50 increasing deposition of silt into the pockets 26 in the same manner as has been described previously herein. The blocks 52 have interlocking extensions 54 with increased length of interstices 48 and fiat longitudinal edges 56 for facilitating the rapid sinking of the revetment in stream currents of high velocity. Flexible connections between the blocks 52 are effected as described above by casting the blocks 52 about flexible cables 30, 30', as aforesaid, the projecting end loops of the latter being secured by clips 34 to launching cables 36.

This illustrative embodiment C of the improved revetment of the present invention illustrates (a) the provision of the vertical sides or baflies 50 for the recesses or pockets 26 for interrupting and retarding smooth, high-velocity currents flowing along the top exposed surface of the revetment; (b) eliminating straight uninterrupted interstices between the blocks along the line of current flow by interlocking adjacent extensions 54 of contiguous blocks S2; (c) retaining conventional width of interstices between blocks 52 by using conventional fiat longitudinal surfaces 56 instead of additional openings in the individual blocks 52 to facilitate the sinking of the revetment mattress in currents of high velocity while retaining fiexibility between the blocks by casting the successive blocks within a square on a fiexible reinforcing fabric of high tensile strength.

In this embodiment C, it will be seen that the patterns of the recesses or pockets and of the projections 54 are repeated on alternate blocks of each series, as shown on Figs. 3, 6, 9, and 12, such duplication of patterns following generally similarly the duplication of patterns of embodiments A and B illustrated in Figs. l, 4, 7, and 10, and Figs. 2, 5, 8, and 11, respectively, of the accompanying drawings.

While the attached drawings and foregoing detailed description are directed to preferred modified embodiments of the improvements of the present invention, it will be apparent that further modifications of structural details and features of the improved construction may become suggested to one skilled in the art without departing from the spirit and concept of the invention; and it will be understood, therefore, that it is intended and desired to embrace within the scope of the invention such modifications and changes as may be necessary or desirable to adapt it to varying conditions and uses as dened by the appended claims.

Having thus described my invention, what I claim as new and wish to secure by Letters Patent is:

l. An articulated revetment for protecting shore lines such as river banks against erosion by water currents, comprising serially disposed rows of substantially at rigid blocks having substantially square transverse edges defining ends of the blocks and convexedly rounded front and rear longitudinal surfaces, flexible cables flexibly interconnecting the blocks in longitudinal and transverse directions, the cables reinforcing the blocks and interconnecting one block to a succeeding block and thereby interconnecting the blocks in both longitudinal and transverse directions to form a continuous articulated revetment while defining reinforcing means for the blocks, each block having an upper surface and a lower surface, the said lower surface being adapted to lie firmly against the river bank, the upper surface of each block being provided with a plurality of rows of recesses having a depth less than the thickness between the upper and lower surfaces of the blocks and having vertical sides defining vertically disposed riles for abruptly breaking and interrupting continuity of smooth-ffowing, silt-bearing current streams f fiowing along the blocksl for causing sudden retardation of such current streams for releasing silt therefrom into the recesses for increasingly firmly embedding the revetment in its launched position by progressive increase in weight as accumulations of silt and solids increase in the recesses, and openings extending entirely through the blocks from the recesses for enabling water to enter the recesses from bottom portions thereof for promoting rapid sinking of the revetment when the revetment is being operatively launched.

2. An articulated revetment as claimed in claim 1, wherein the silt-receiving recesses are disposed in aligned rows, the recesses of selected rows being dimensonally substantially larger in area than the recesses of the remaining rows.

3. An articulated revetment as claimed in claim 2, wheerin the rows of silt-receiving recesses are arranged n two alternating patterns in the blocks of each row, one of the patterns being a row of large-area recesses above two rows of small-area recesses in a block of the revetment, the other of the two patterns being a row of the large-area recesses intermediate two rows of the small-area recesses, the said patterns being repeated alternately in each row of the blocks, the patterns being also alternated throughout alternate rows of blocks of the revetment.

4. An articulated revetment as claimed in claim 3, in which each recess is provided with a pair of through-port openings extending vertically through the block from the bottom of each recess, the port openings all being of the same diameter.

References Cited in the file of this patent UNITED STATES PATENTS 929,728 Taylor Aug. 3, 1909 954,283 Hawkes Apr. 5, 1910 1,071,091 Rogers Aug. 26, 1913 1,144,143 McGillivray .Tune 22, 1915 1,164,708 Edinger Dec. 21, 1915 FOREIGN PATENTS 495,480 Belgium May 31, 1950

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