US3396541A - Means and method for construction sand drains in the earth's surface - Google Patents

Description

B. A. LAMBERTON MEANS AND METHOD FOR CONSTRUCTING SAND Aug. 13, 1968 DRAINS IN THE EARTH'S SURFACE 2 Sheets-Sheet 1 Filed April 19, 1965 FIG. 2

INVENTOR.

BRUCE LAMBERTON ATTORNEYS Aug. 13, 1968 s. A. LAMBERTON MEANS AND METHOD FOR CONSTRUCTING SAND DRAINS IN THE EARTH'S SURFACE 2 Sheets-Sheet 2 Filed April 19, 1965 INVENTOR- BRUCE LAMBERTON ATTORNEYS United States Patent 3,396,541 MEANS AND METHOD FOR CONSTRUCTIVG SAND DRAINS IN THE EARTHS SURFACE Bruce Alexander Lamberton, Berea, Ohio Intrusion- Prepakt, Inc., 1705 Superior Bldg., Cleveland, Ohio 44114 Filed Apr. 19, 1965, Ser. No. 448,974 9 Claims. (CI. 6111) ABSTRACT OF THE DISCLOSURE A sand drain comprising a flexible, porous tube of fabric material filled with sand inserted in a hole in the earth. A plurality of tubes may be arranged in side by side relationship around the perimeter of the hole with loose aggregate material in the core or concentric tubes of sand and aggregate may be used. The tube may be formed in a continuous strip, filled with sand and laid in a trench in the earth.

Disclosure This invention pertains to the art of water drainage from the earths surface and more particularly to means and method for constructing sand drains for this purpose.

There are areas in the world where the water content of the surface or subsurface soil is so high that the soil has such a low load bearing capacity that it is impossible to erect structures thereover without first providing means for draining water from the soil. Numerous arrangements have been attempted in the past to remove such water. For example, large weights have been placed in the soil in an effort to squeeze the water out. A further and more common method has been to dig a vertical hole in the soil to a predetermined depth and then fill this liole with sand or aggregate or both such that the water can bleed into the sand or aggregate and thence upwardly to the top where it can then be pumped or allowed to drain away. Such sand drains have proven particularly effective in removing water.

Difficulty has been experienced in the past, however, in the forming of such sand drains or in keeping them open. Thus, in the time lapse between the digging of the hole and filling it with sand, the walls of the hole often collapse, in full or in part, either restricting the depth of the hole or if the collapsing should take place after a portion of the sand has been poured thereinto, blocking off the lower portions of the hole from the upper portions thereof and thus impeding or preventing the necessary drainage characteristics. A further problem has been that even though the hole may have been properly filled with sand, shifting or collapsing of the earths surface after a passage of time results in the sand drain being completely blocked such that thereafter the drain is unable to properly function.

A still further problem has been that over a period of time the water flowing from the soil into the sand carries with it particles of the soil into the sand and finally blocks up and close the passages between the sand particles.

A still further problem has been that it was not always possible to use the optimum size of sand particles or to obtain a gradation of the size of sand particles from the outer portions toward the core or even to use the aggregate as a core for the sand column.

In horizontal drains, laying of tile is expensive and time consuming. Also the tiles tend to plug up after short periods of use.

The present invention contemplates means and meth- Patented Aug. 13, 1968 "ice od for constructing sand drains in the earths surface which overcomes all of the above-referred to difliculties and others and provides a sand drain which is easily and quickly constructed and which will not block up due to any cause.

In accordance with the method of the present invention, a hole of a desired diameter and depth is first formed in the ground and then a flexible, porous tube of woven fabric is placed in the hole, such tube, either before or after being inserted into the hole, being filled with sand or other particulate material through which water can readily flow. In the preferred embodiments of the invention, the tube is filled with the sand prior to being inserted into the hole.

In accordance with another aspect of the invention, a sand drain is provided comprised of an elongated tube of flexible, porous woven fabric material closed at at least the lower end and filled with a particulate material, such as sand or aggregate.

Further in accordance with the invention, a sand drain is provided comprised of a pair of inner and outer coaxial tubes of woven fabric, porous material with the inner tube filled with a coarse aggregate and the space between the inner and outer tubes being filled with sand.

Further in accordance with the invention, a method of providing horizontal drains is provided comprising progressively forming a continuous trench in the earths surface, progressively forming a sand filled tube of flexible porous material, progressively placing such filled tube at the bottom of the trench and progressively covering the tube.

The principal object of the invention is the provision of a new and improved means and method for constructing sand drains in the earths surface which is quickly installed and which will not plug up while in use.

Another object of the invention is the provision of a new and improved sand drain for use in the earths surface which enables the use of the optimum size of sand particle.

Another object of the invention is the provision of a new and improved sand drain wherein the center core of the drain may be open or have a particle size much larger than the outer portions thereof.

Another object of the invention is the provision of a new and improved method for forming sand drains in the earth wherein the sand drain may be inserted into a newly formed opening before the walls of the opening have had a chance to cave in.

Another object of the invention is the provision of a new and improved sand drain in the earths surface which will not be blocked up by horizontal shifts in various layers of the earths surface.

Another object of the invention is the provision of a new and improved sand drain wherein intermingling of the sand and the surrounding soil is prevented.

Another object is the provision of a new and improved method of installing horizontal drains in the earths surface which is simple, rapid and economical.

The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawing which is a part hereof and wherein:

FIGURE 1 is a cross-sectional view of the earths surface showing one method of forming the hole to receive a sand drain of the present invention;

FIGURE 2 is a view similar to FIGURE 1 showing a sand drain supported in position for filling and partially lowered into the hole of FIGURE 1;

FIGURE 3 is a cross-sectional view of a sand drain having an alternative form of reinforcement;

FIGURE 4 is a fragmentary, cross-sectional view of the fabric tube of FIGURES 2 and 3 showing the arrangement of the seam;

FIGURE 5 is a top cross-sectional view of an alternative form of sand drain;

FIGURE 6 is a fragmentary perspective view of the sand drain of FIGURE 5 prior to being shaped into the form of a tube; and,

FIGURE 7 is a schematic view of apparatus and method for continuously laying horizontal sand drain and illustrating an alternative embodiment of the invention.

Referring now to the drawings wherein the showings are for the purposes of illustrating preferred embodiments of the invention only and not for the purpose of limiting same, FIGURE 1 shows a fragmentary cross section of the earths surface 10 with an auger 11 being rotatably driven thereinto for the purpose of drilling a vertically extending opening 12. The auger 11 may take any known construction and may be rotated by any suitable power means not shown. The diameter of the hole may be as desired, but in the preferred embodiments, will be on the order of from 10-12 inches. The depth of the hole 12 is that required to provide the desired depth of drainage and, of course, will vary with dilferent soils and different locations.

The earth 13 removed from the hole 12 may be allowed to remain around the auger or it may be removed as fast as the auger 11 brings it up from the bottom of the hole. When the hole is completed, the auger 11 may be removed.

Prior to the completion of the drilling of the hole 12, a sand drain for insertion into such hole has preferably been prepared. In accordance with the preferred embodiment of the invention, such sand drain is comprised of an elongated tube of flexible, porous fabric material, the lower end of which has been sealed closed by means of a suitable tie 21. This tube 20 is then filled with a particulate material such as loose sand or aggregate or a mixture of both 22, and the upper end tied as at 24.

This tube 20 may be filled in any desired way, but in the preferred embodiment, the upper end of the tube 20 is folded out and down over a steel ring 26 having a downwardly and inwardly inclined outer surface 27. A clamping ring 28 having an upwardly and outwardly inclined surface 29 clamps the folded over portion of the tube 25 between the two inclined surfaces 27, 29. Support members 30 extend upwardly from the clamping ring 28 and are supported by overhead support means not shown.

Sand or gravel from a hopper 32 is then fed into the open upper end of the tube 20 through a flexible hose 33. Obviously, the exact method of filling the tube with the sand or gravel forms no part of the present invention. After the tube 20 is filled to the desired amount, it is then tied off as at 24 as heretofore described. Preferably, as the auger 11 is withdrawn from the hole 12, the filled tube 20 is supported vertically adjacent to the hole 12 so that as soon as the auger 11 is out of the way, the filled tube 20 may be quickly lowered into the hole 12.

Normally the tube 20 will have an inflated diameter of from 1-2 inches less than that of the hole 12 so that it inserts readily thereinto and in the event of any projecting rocks or the like, there is no danger of the tube 20 being torn as it is being inserted. The length of the tube is such that when bottomed in the hole 12, it will be generally flush with the earths surface.

It is to be noted that the tube 20 is of flexible, porous material. The size of the openings therethrough should not be substantially greater than the smallest size of the particles of the material which will be placed into the tube. Such materials normally have flow characteristics and inflate the tube 20 with a considerable pressure, particularly at the lower end. The filled tube 20 is normally quite rigid due to this internal radial pressure.

Also, the sand in the tube 20 may have considerable weight beyond that of the strength of the fabric ma terial. If this is the case, suitable longitudinal reinforcing means can be provided. In the embodiment shown in FIGURE 2, such reinforcing means is comprised of an elongated rod 40 which extends coaxially through the filled tube 20 from a point below the tie 21 to a point above the tie 24. This member 40 may have a loop 41 provided therein so that it can be suitably engaged by overhead supports not shown. The lower end of the rod 40 is suitably threaded into a flat Washer 43 and the entire weight of the filled tube 20 thus rests on this washer 43 and is transferred to the rod 40. Once the filled tube has been lowered to the bottom of the hole 12, the rod 41 can be unscrewed from the washer 43 and reused.

FIGURE 3 shows an alternative arrangement for reinforcing the filled tube 20. In this embodiment of the invention, a plurality, three or four rods 50 extend vertically the length of the tube in engagement with the outside thereof. These rods 50 engage in threaded openings in a plate 51 positioned at the lower end of the filled tube 20 and the weight of the filled tube rests on this plate 51 and is thus transferred to the rods 50. The upper end of the rods 50 extend through suitable openings in a plate 52 and threaded nuts 53 engage the end thereof. An eye 54 connected to the plate 52 is adapted to be engaged by an overhead supporting means, not shown. As soon as the sand drain of FIGURE 3 is lowered into position in the hole 12, the nuts 53 and plate 52 may be removed and then the rod 50 may be unscrewed from the plate 51 and recovered for reuse.

The use of the rods 40 or 50 makes it possible to use a flexible material for making the tube which has considerable less strength requirements than would be the case if the rods 40 or 50 were not employed.

The tube 20 can be formed of any one of a number of different materials, but in the preferred embodiment is formed from a woven fabric of one of the synthetic materials such as nylon, Orlon or the like. The individual strands of this fabric are preferably of the twisted type and are coated so that they will pass water more freely. These synthetic materials have the ability of not rotting away when left in the earths surface and exposed to water over prolonged periods and further have the required strength characteristics to withstand without rupturing the various pressures and forces imposed on the filled tube by the sand and gravel on the inside thereof or by the shifting of the earths surface after the sand drain has been installed.

The tube 20 may be formed in any one of a number of different ways such as being woven to the shape of a tube, but in the preferred embodiment of the invention, an elongated strip 60 of the desired material is folded over longitudinally so that its edges 61, 62 overlap, with the outer surface of the edge 61 facing or opposing the inner surface of the edge 62 and these edges are then preferably cemented with a flexible cement 63 which has substantial shear strength characteristics. If desired, stitching 64 can be employed to hold the edges 61, 62 in overlapping engagement until the cement 63 has had a chance to set up. Such a method of fabricating the tube provides a seam which has the strength necessary to resist the very high radial pressures which can be developed on the inside of the tube 20.

It will be appreciated that in some instances the tube 20 in a collapsed condition can be lowered into the hole 12 and then the particulate material poured thereinto.

The material from which the tube 20 is formed must be water permeable, that is to say, it must have a willciently loose weave that water can readily flow therethrough while at the same time the size of the openings must be small enough to prevent the particles of the sand 22 from flowing out through such holes, at least to an appreciable degree. Normally, the maximum size of the openings of the fabric should not be greater than one and one-half times the minimum size of the majority of the particles of the sand 22.

It will also be understood that the tube 20 can be filled with sand, gravel or a mixture of both.

FIGURE 5 shows an alternative form of sand drain constructed in accordance with the present invention. Such a sand drain consists of a plurality of vertically extending tubes 65 arranged in side-by-side engagement around the outer periphery of the hole 12. These tubes 65 are preferably comprised of elongated tubes of woven fabric material filled with suitable sand or aggregate. These tubes 65 may be inserted individually into the hole 12 in the arrangement shown in FIGURE 5 or in a preferred embodiment, are made from a blanket of woven fabric material made up of two layers 68, 69 which are joined at spaced longitudinally extending points 70. This joining may take place by stitching or in the preferred embodiment, by having the weave of the layer 68 extend across the layer 69. The ends of the layers 68, 69' may be suitably joined by cementing or stitching as at 72 to hold the tubes in the circular configuration of FIGURE 5.

The core defined by the plurality of tubes 65 may be left void or filled with a coarse aggregate or a loose sand as desired.

FIGURE 7 shows a still alternative embodiment of the invention, particularly adapted for installing horizontal drains in the earths surface in a continuous manner. Heretofore it has been conventional to dig a trench, fill the trench with suitable tile and then cover over the top with the dirt which was dug out of the trench. In the embodiment of the invention shown in FIGURE 7, a wheeled vehicle 80 is provided which is moved from right to left by any suitable power means not shown. Means for digging the trench is shown as being in the form of a plow blade 81 extending downwardly into the earth to a desired depth. This blade 81 cuts a furrow or channel 82 in the earth, throwing the dirt into a windrow 83 along the sides of the channel 82.

At the front end of the vehicle 80 there is a reel 85 of an elongated strip 36 of woven fabric material which strip 86 is unwound from the reel 85 as the vehicle 80 moves to the left. A funnel-shaped guide 87 forces the edges of the strip 86 into overlapping relationship to form a tube as at 90. If necessary, cementing or stitching means, not shown, can be provided for fastening these overlapping edges together. Sand is continuously supplied from a hopper 88 through a flexible tube 89 into the inside of this tube 90 as fast as it forms. The filled tube 90 is then supported on a slide 91 on the rear of the vehicle and is gradually lowered into the trench 82 as the vehicle 80 moves to the left, it being noted that the sand on the inside of the filled tube 90 keeps the fabric inflated into the shape of an elongated cylinder. As soon as the filled tube 90 is on the bottom of the trench 82, the windrow 83 may be pushed back into the trench as at 95. Water may then seep from the surrounding soil through the porous walls of the tube 90 and thence longitudinally through the sand on the inside of the tube 90 to suitable drainage points not shown.

It will be appreciated that with a sand drain so formed, shifting of the earths surface will not affect the ability of the drain to conduct water therethrough. In fact, in all of the embodiments of the invention, even though the surrounding earth should shift so as to totally collapse the tube by displacing the sand on the inside, there will still always remain a wick of the porous fabric material through which the water can continue to flow.

In the preferred embodiment of the invention, the tube 20 was filled prior to insertion into the opening 12. Obviously, the tube 20 may be inserted into the opening 12 in the unfilled condition and sand, gravel or aggregate poured into the tube 20 or if desired, and particularly where the walls defining the tube 12 have little or no strength, an alternative form of insertion of the tube 20 may be necessary. Thus, the auger 11 may be provided with a hollow shaft and the tube 20 in radially collapsed form may be forced lengthwise through this hollow shaft to the bottom of the auger. Also a hose or a rigid pipe extends internally of the collapsed tube 20 to the bottom end thereof. As the auger 11 is withdrawn, the tube 20 is held stationary, that is to say, it is pushed out of the bottom of the hollow shafted auger as the auger 11 is being withdrawn. At the same time, a slurry of sand is pumped downwardly through the pipe so as to fill and inflate the lower end of the tube 20 as fast as it is pushed out of the lower end of the hollow shaft of the auger. In this way, even though the walls of the opening 12 tend to collapse as the auger 11 is being withdrawn, as soon as the auger 12 has been even in part withdrawn, the tube 20 inflated with the sand expands outwardly, engages the walls and prevents their collapse.

By particulate material is meant a non-water-soluble granular substance having a grain size sufficiently large that water can readily seep therethrough at rates faster than in ordinary soils. A grain size of approximately & inch or larger is contemplated. Obviously, as the grain or particle size increases, the volume of the voids therebetween increases and the water flow therethrough is facilitated.

It will thus be seen that preferred embodiments of the invention have been described which accomplish all of the objects heretofore set forth and others and provide an arrangement for quickly and economically installing said drains which assures a drain of full depth and which will not plug or block up over long periods of time.

The invention has been described with particular ref erence to such preferred embodiments. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification and it is my intention to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalent thereof.

Having thus described my invention, I claim:

1. A method of forming said drains in the earths surface comprising forming a hole in the earths surface, filling an elongated flexible, porous tube of fabric material with sand and inserting a closed end of such filled tube into the hole and lowering the tube in an upright position to substantially fill the hole to provide a drain.

2. The method of forming a sand drain in the earths surface comprising forming a hole in the earths surface, inserting a tube of flexible, porous fabric material into and lengthwise of such hole and filling the inserted tube with sand, the sand inflating the tube to support the tube in the hole to form a drain therein.

3. The method of forming sand drains in the earths surface comprising forming a hole in the earths surface of a predetermined diameter and to the desired depth of the sand drain, providing an elongated tube of flexible, porous fabric material, filling such tube with sand and immediately after the forming of the hole, inserting the filled tube into the hole in an upright position and lowering the tube to substantially fill the hole to provide a drain.

4. A sand drain comprised of an elongated tube of flexible, porous fabric material, means closing the lower end thereof, rigid means defining a load bearing support at said end, a reinforcing member extending the length of such tube and removably attached at one end to said rigid means, the other end of the member providing means for supporting the tube in an upright position, and sand filling such tube and expanding same.

5. A sand drain comprised of a pair of coaxial tubes of flexible, porous fabric material extending in the earths surface, the inner tube having a diameter of less than that of the outer tube and aggregate filling the inner tube and a sand filling the space between the inner and outer tubes, the aggregate and sand inflating the tubes Whh the outer tube being in engagement with the earth to provide drainage.

6. A sand drain comprised of a plurality of longitudinally extending tubes of woven flexible porous fabric material filled with a sand-like material said tubes being arranged in longitudinal side-by-side relationship lengthwise of and around the perimeter of a generally circular hole in the earths surface.

7. The combination of claim 6 wherein the core defined by such plurality of filled tubes is filled with a loose aggregate material.

8. A method of manufacturing a sand drain in the earths surface comprising continuously forming a trench in the earths surface, continuously forming a strip of Woven porous fabric material into the shape of a flexible tube, filling such tube with a loose sand-like material, lowering the filled tube into such trench and filling in the remainder of the trench adjacent the tube.

9. A method of manufacturing a sand drain in the earths surface comprising: providing a hollow shafted auger, screwing such auger into the earths surface to the desired depth of the sand drain, providing an elongated tube of flexible, porous fabric material in the hollow shaft of such auger, the lower end of such tube being closed, withdrawing such auger while simultaneously pushing said tube through the hollow shaft of the auger into the cavity formed by the withdrawal of the auger and pumping a granular material into such tube as it emerges from the end of the hollow shafted auger.

References Cited UNITED STATES PATENTS 6/1906 Cummings 61-53.62 X 12/1910 Bouslaugh 61-11 8/1922 Maury 166-228 X 11/1932 Records 16656 12/1951 Kjellman 61-11 11/1953 Jourdain 61-11 9/1956 Kennon 6113 6/1962 Jameson et al. 166228 X 11/1965 Diamond et a1 61-11 X 11/1965 Boa 6l-72.6 9/1966 Landau 6153.'64 X FOREIGN PATENTS 6/1955 Italy. 4/ 1962 Great Britain. 10/1962 France. 8/ 1963 France.

OTHER REFERENCES Roads and Streets, page 99, September 1955. Civil Engineering, pages 31-33, January 1963.

' EARL I. WITMER, Primary Examiner.

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