CA2229758C - Drainage method and strap draining materials therefor - Google Patents
Drainage method and strap draining materials therefor Download PDFInfo
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- CA2229758C CA2229758C CA002229758A CA2229758A CA2229758C CA 2229758 C CA2229758 C CA 2229758C CA 002229758 A CA002229758 A CA 002229758A CA 2229758 A CA2229758 A CA 2229758A CA 2229758 C CA2229758 C CA 2229758C
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- strap
- drain material
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- notches
- drain
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/02—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against ground humidity or ground water
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02B—HYDRAULIC ENGINEERING
- E02B11/00—Drainage of soil, e.g. for agricultural purposes
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- General Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Structural Engineering (AREA)
- Civil Engineering (AREA)
- Mechanical Engineering (AREA)
- Agronomy & Crop Science (AREA)
- Environmental & Geological Engineering (AREA)
- Hydrology & Water Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Road Paving Structures (AREA)
Abstract
A drainage method comprises the step of absorbing liquid from soil, by capillary action, into a plurality of drain-collecting slots provided on at least one surface of a strap-like drain material embedded in the soil. The slots include a plurality of notches in the surface of the drain material that are sufficiently small to create a capillary effect and that extend to the slots which are larger than the notches. The slots are arranged in a spaced-apart fashion across a width of the drain material and extend along its length. The notches correspond to the plurality of slots; the notches extending from the slots to a surface of the drain material. Each notch is sized such that the notch is capable of creating a capillary action and is adapted to draw liquid from outside into the slot corresponding to the notch.
Description
DRAINAGE METHOD AND STRAP
DRAINING MATERIALS THEREFOR
BACKGROUND OF THE INVENTION
The present invention relates to a novel drainage method and the strap draining materials therefor and, in particular, to a draining method adapted for use in drainage system in the soil conservation on mountain slopes, agricultural industry and in civil engineering work and to flexible thin sheet like draining straps having a high resistance to pressure and a high efficiency of drain absorption.
Conventionally, the most frequent use of water permeable and draining materials in drainage in the soil conservation on mountain slopes, underground irrigation and drainage on farms, and the civil engineering work on tunnel road bases and retaining walls are of a tubular type, that is, the so-called permeability pipes or drain pipes. The basic structure of a drain pipe is all that the circumference of at least of more than a half of the upper half portion of the circular tubular pipe is opened up with numerous tiny cracks densely distributed like meshes of a net for collecting infiltration water from the soil cover into the non-porous water collecting part of the lower half portion in the pipe and from there again water to flow out along the longitudinal direction of the pipe.
However, because the infiltration water moves water to flow downwardly into the lower half portion of the pipe by the water head and the water gravity, it must also carry along the tiny sandy particles into the meshes. Certainly, the sandy particles after collecting for some time gradually seal the meshes resulting thus in a blockade. Even though a part of the sandy particles entering the pipe can be discharged together with the water that has infiltrated into the pipe, because the amount of water collecting in the pipe is small and the speed of drain flow is low, a majority of sandy particles will settle on the lower half portion of the pipe. When collecting over a long period, it also results in disadvantages that there is blockade in the pipe and reduction in the amount of drain.
Sometimes, to prevent blocking of the meshes, there is covered on the outside of the drain pipe with a non-woven coating or a synthetic fiber gauze as the filtering layer thereby forming a multiple-layer permeability pipe or drain pipe.
However, since after use over a period of such a filtering layer blockade can still occur, its use would merely accomplish the effect of prolonging the life only.
Furthermore, as drain pipes of the kind are mostly made of a hard plastics, this makes the construction process on embedding relatively inconvenient. Again, as the total area of the meshes provided on the unit area of the circumference of the drain pipe to act as the water inlet hole differs greatly from the pipe diameter sectional area (water service sectional area) and the actual amount of drainage in the drain pipes is less than one third of its sectional area, no siphonic action will thus be created. On the other hand, if the circumference of the pipe is formed densely with meshes, there will be a great reduction in theresistanee to pressure in the drain pipe and the pipe can hardly be resistant to the soil pressure and the heavy pressure from vehicles, the drain pipe will get distorted easily and will even break by pressure leading to a blockade in the meshes or the pipe.
In order that the drain pipe be flexible and bendable to facilitate construction, a soft flexible permeable pipe made of various materials of PVC coated screw-type spring steel wire, non-woven fabric tube and nylon yarn has also been disclosed.
However, even with such a flexible permeable pipe the problems of the aforesaid blockade in the meshes and the resistance to pressure still remain.
Others also include disclosure of forming a screw ditch on the outer circumference of a hard plastic drain pipe and in which the meshes are provided inside the ditch whereby it enhances the strength of the pipe body and improves the absorption efficiency There is disclosed also another type of a non-tubular type of drain sheet.
This type of drain strap is formed by coating on the surface of a hard plastics formed concavo-convex support body with a layer of felt non-woven fabric. The support body also has the two sides formed in ditches, however, the opening of the ditches is broader than the ditch bottom.
It is a purpose of the present invention to provide a new draining material which differs in construction, shape and principle from the foregoing various drain pipes and sheets, and which provides a large drainage of high absorption rate, a resistance to pressure, resists blockage and is adapted for use in most kinds of drainage systems.
DRAINING MATERIALS THEREFOR
BACKGROUND OF THE INVENTION
The present invention relates to a novel drainage method and the strap draining materials therefor and, in particular, to a draining method adapted for use in drainage system in the soil conservation on mountain slopes, agricultural industry and in civil engineering work and to flexible thin sheet like draining straps having a high resistance to pressure and a high efficiency of drain absorption.
Conventionally, the most frequent use of water permeable and draining materials in drainage in the soil conservation on mountain slopes, underground irrigation and drainage on farms, and the civil engineering work on tunnel road bases and retaining walls are of a tubular type, that is, the so-called permeability pipes or drain pipes. The basic structure of a drain pipe is all that the circumference of at least of more than a half of the upper half portion of the circular tubular pipe is opened up with numerous tiny cracks densely distributed like meshes of a net for collecting infiltration water from the soil cover into the non-porous water collecting part of the lower half portion in the pipe and from there again water to flow out along the longitudinal direction of the pipe.
However, because the infiltration water moves water to flow downwardly into the lower half portion of the pipe by the water head and the water gravity, it must also carry along the tiny sandy particles into the meshes. Certainly, the sandy particles after collecting for some time gradually seal the meshes resulting thus in a blockade. Even though a part of the sandy particles entering the pipe can be discharged together with the water that has infiltrated into the pipe, because the amount of water collecting in the pipe is small and the speed of drain flow is low, a majority of sandy particles will settle on the lower half portion of the pipe. When collecting over a long period, it also results in disadvantages that there is blockade in the pipe and reduction in the amount of drain.
Sometimes, to prevent blocking of the meshes, there is covered on the outside of the drain pipe with a non-woven coating or a synthetic fiber gauze as the filtering layer thereby forming a multiple-layer permeability pipe or drain pipe.
However, since after use over a period of such a filtering layer blockade can still occur, its use would merely accomplish the effect of prolonging the life only.
Furthermore, as drain pipes of the kind are mostly made of a hard plastics, this makes the construction process on embedding relatively inconvenient. Again, as the total area of the meshes provided on the unit area of the circumference of the drain pipe to act as the water inlet hole differs greatly from the pipe diameter sectional area (water service sectional area) and the actual amount of drainage in the drain pipes is less than one third of its sectional area, no siphonic action will thus be created. On the other hand, if the circumference of the pipe is formed densely with meshes, there will be a great reduction in theresistanee to pressure in the drain pipe and the pipe can hardly be resistant to the soil pressure and the heavy pressure from vehicles, the drain pipe will get distorted easily and will even break by pressure leading to a blockade in the meshes or the pipe.
In order that the drain pipe be flexible and bendable to facilitate construction, a soft flexible permeable pipe made of various materials of PVC coated screw-type spring steel wire, non-woven fabric tube and nylon yarn has also been disclosed.
However, even with such a flexible permeable pipe the problems of the aforesaid blockade in the meshes and the resistance to pressure still remain.
Others also include disclosure of forming a screw ditch on the outer circumference of a hard plastic drain pipe and in which the meshes are provided inside the ditch whereby it enhances the strength of the pipe body and improves the absorption efficiency There is disclosed also another type of a non-tubular type of drain sheet.
This type of drain strap is formed by coating on the surface of a hard plastics formed concavo-convex support body with a layer of felt non-woven fabric. The support body also has the two sides formed in ditches, however, the opening of the ditches is broader than the ditch bottom.
It is a purpose of the present invention to provide a new draining material which differs in construction, shape and principle from the foregoing various drain pipes and sheets, and which provides a large drainage of high absorption rate, a resistance to pressure, resists blockage and is adapted for use in most kinds of drainage systems.
SUMMARY OF THE INVENTION
In accordance with this invention liquid is absorbed from soil, by capillary action, into a plurality of drain-collecting slots provided on at least one surface of a strap-like drain material embedded in the soil. The slots include a plurality of notches in the surface of the drain material which are. smaller than and extend to the slots and are sufficiently small to create a capillary effect, and the slots extend along a longitudinal direction of the drain material.
The strap-like drain material of the invention comprises a strap having a plurality of slots arranged in a spaced-apart fashion across a width of the strap and extending along a length of the strap, and a plurality of notches. Each one of the plurality of notches corresponds to one of the plurality of slots, the notches extending from the slots to a surface of the strap; each notch being sized such that the notch is capable of creating a capillary action and drawing liquid from outside the strap and into the slot corresponding to that notch.
Thus, an aspect of the invention provides a drainage method whereby the capillary action produced at the narrow crack notches of the small diameter drain-collecting slots, extending longitudinally and provided densely on the surface of the thin strap-draining materials embedded within the soil, is used to absorb water contained in the soil into the slots, and whereby the siphonic force produced by the drop of water level is used to enhance absorption and collect and discharge water from one end of the slots.
An embodiment of the invention provides a drainage method wherein notches of the drain-collecting slots of the draining materials face downwardly, and water not only enters the slots by the capillary action on the one hand, but the surface tension of water produced at the narrow notches is used to support water pressure in the slots not to leak back on the other hand. At the same time the siphoning force produced at the section of drop is used to collect and discharge water, and because of the notches facing downwardly, it is possible to effectively prevent the drawback that sand particles sink because of gravity and collect at and block the slots.
Another embodiment of the invention provides a drainage method in which a strap-draining material, having on one side densely provided with small hole diameter drain-collecting slots extending whole length along the longitudinal direction and having the notches capable of producing capillary action, is embedded between soil cover or stratum and the wall of a permeable structure such that the side with the drain-collecting slots is in contact with the soil cover or stratum while the side which is without drain-collecting slots is adjacent the wall of the structure. The water content from the soil is suctioned through the notches into the slots by capillary action, and water inside the slots is collected and discharged by the siphoning force created by the drop of water level at the two ends of the slots while at the same time, on the side which is without drain-collecting slots water from the soil is blocked from permeating into the wall of the structure.
Another aspect of the invention is the provision of a strap-like draining material capable of effectively implementing the draining method, in which the draining material is formed of a weather-resistant, thermoplastic synthetic resin into a thin sheet elongated strap body, at least one side thereof having a plurality of tiny drain-collecting slots densely arranged spaced-apart along the direction of the breadth of the strap and extending the whole length of the strap in the direction of the strap length.
Notches thereof form cracks narrow enough to create a capillary action, and inside the slots there are ditches in section of expanded small round holes to facilitate collection and discharge of the water that is absorbed into the slots.
In another aspect the invention can provide a strap-draining material which can be used as a waterproof membrane as well as a draining material in basement and tunnel constructions. Also, the side that is without drain-collecting slots can have an even and smooth surface or a plain surface having a plurality of reinforced ribs.
Alternatively, the plain surface can have a reinforcement member for enhancing resistance to soil pressure.
If preferred the side which has slots can be provided with a non-woven filter material.
Therefore, the drainage method of the invention is adapted for use in a system of soil conservation on mountain slopes, underground drainage in fruit ranges and farmlands, and drainage in road bases. It utilizes a draining strap with at least one side having a plurality of parallel-arranged small diameter drain-collecting slots extending along the length of the band and with notches in the shape of capillary cracks, which is buried in any form, preferably laid flat, within the soil layer to be drained.
By capillary action at the notches of the slots, water content in the soil is absorbed into the drain-collecting slots, and water is drawn, collected and drained through the siphoning force created by the drop of water level at the two ends or at any one section of the slot.
4a For draining materials, flexible plastic materials of PVC, PE or PP are used in forming thin sheet-like elongated strap bodies. At least one surface of the strap bodies is formed with a plurality of narrow drain-collecting ditches densely arranged spaced-apart in the direction of breadth of the strap and extending the length of the band.
An opening of the ditch is formed into capillary cracks, while the ditch portion is formed in an expanded small hole, in section. In draining materials of another form, the surface where there is no formation of drain-collecting ditches is formed in a flat and even surface, and to enhance resistance to pressure and the form protecting the draining materials, this flat surface can be provided with a U-shaped reinforcing material. Having also the function of a water-resistant membrane, the draining strap may be used in an infiltration prevention and drainage system in basement and tunnel constructions.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention will be apparent from the .
following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings:
FIG. 1 is a perspective view showing a first embodiment of the draining material of the present invention;
FIG. 2 is a perspective view showing a second embodiment of the draining material of the present invention;
FIG. 3 is a perspective view showing a third embodiment of the draining material of the present invention;
FIG. 4(A), (B) and (C) are front views showing the deformation examples of the draining material attached with a reinforcement material;
FIG. 5 is a front view showing a fourth embodiment of the draining material of the present invention;
FIG. 6 is a schematic view showing the apparatus of Examples 1 and 2 of the draining material of the present invention;
FIG. 7 is a schematic view showing the apparatus of Example 3 of the draining material of the present invention; and -$-FIG. 8(A) and (B) sow respectively the partial enlarged views of the draining material with slot portions facing upwardly and downwardly illustrating the principle of drain absorption.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of one embodiment of the draining material of the present invention, with a section cut off along the direction of its length, in which the numeral 1 represents the elongated strap draining material with a flat shape in section.
This draining material 1 is a flexible strap body made by forming of a weather-resistant thermoplastic synthetic resin, one side of which is provided with a plurality of tiny drain collecting slots 2 densely arranged spaced-apart along the direction of breadth and parallel extending whole length along the longitudinal direction. Notches 21 of the slots 2 are formed in narrow cracks sufficient to create a capillary action and are communicated inwardly with small round hole slots 22 with an expanded section.
The other side of the strap body is formed in a flat and smooth surface 3. In this manner, the entire strap body is formed in a strap of reel band having the two sides both actually of a plain surface capable of being rolled up like a bolt of cloth and cut in appropriate length for use according to need. The notches 21 are formed in inlet portions to absorb water by capillary phenomenon while the slots 22 are formed in channels for collecting and draining water, the action and principle of which will be described hereinbelow.
FIG. 2 is a second embodiment of the draining material of the present invention, in which a draining material lA is basically same as the first embodiment of a flat elongated strap body made by forming of a thermoplastic synthetic resin. However, both the upper and lower sides of the strap body are formed with drain collecting slots 2 of same construction as the first embodiment. In the present embodiment, the drain collecting slots 2 on the two sides of the draining strap lA are maintained on the same pitch and opposite to each other vertically. However, it is also possible if a vertically staggered arrangement is followed.
FIG. 3 is a third embodiment of the draining material of the present invention, where in order to enable the soft flexible draining material to have a high strength of resistance to soil pressure, there is attached to the flat and smooth surface 3 of the draining material 1 shown in FIG. 1 a reinforcement material 4 formed of a hard plastic material. In the present embodiment, the form material 4 uses simply a U-shaped ri~aterial, however, it is also possible to use, for example, a U-shaped material 4A containing inside the slot numerous ribs, or reinforcement in the form of a rectangularly shaped pipe-like member 4B or other suitable form 4C, as shown in FTGS. 4(A), (B) and (C).
FIG. 5 is a furtheF embodiment of the draining material of the present invention, whereas in the third embodiment one side of the draining material 1 is attached with a hard plastics made reinforcement form material 4 in the present embodiment, however, the reinforcement portion is formed directly integrally with the draining material 1. The reinforcement portion shown in the drawings includes several high and low ribs 41, 42 extending along the longitudinal length, it is apparent however that various modifications can be made. Next, on the one side of the foregoing draining strap I having drain collecting slots 2, if necessary, there may be coated also with a non-woven and nylon yarn as filter material.
A strip of the draining strap 1 of the first embodiment having length 35cm x breadth Scm x thickness 0.3cm with a pitch of holes l.2mm on one side thereof and a total of 40 lanes of drain collecting slots 2 with notches 21 of a breadth 0.1 Smm and slots 22 of a diameter 0.9mm was obtained. With the ode with slots facing upwardly and the inner end higher than the outer end for about 1 cm, the draining strap 1 after the inner end was sealed, was embedded on the bottom inside an acryl transparent plastics made container 5 of breadth 30cm x length 30cm x height 20cm such that the outer end of the draining strap was exposed to the outside for about Gcm as shown in FIG. 6.
Sandy soil of mud and river sand mixed in a ratio of 2 : 1 and slightly pressed to be flat and smooth was filled into the container 5 to a height of l5cm with a remaining height of Scm on the soil surface. This remaining height of Scm on the soil surface was fylled with water 30 x 30 x 5 = 4500cc and after two minutes ( depending upon the rate of water permeation in the mud), water flowed out from the outlet end of the draining strap.
Based on observation of the outflow of water, it has been found that water flows out from about 2/3 of the slots and the state of water flow appears to be in a continuous or intermittent water column of full slots. This indicates that owing to differences in density and rate of water permeation among various parts in the nature of the soil, water absorbed through the notches by the capillary phenomenon enters the sbts one after the other and partially to be collected to form a segment of water column for discharge. At _7_ this time when water column flows towards the outlet end via a drop in the water head, a vacuum suction effect is created in the rear part thereof which again brings another segment of water column of the collected water at the rear part to move forward so that a siphonic action is produced. By means of this siphonic action, water that enters the slots is continuously sucked out thereby improving further the capillary action to accomplish a high rate of water absorption and rate of drainage. That about 1/3 of the slots where there is only a small amount that flows out and the flow stops or there is no water to flow out, it is because the force of infiltration from the upper layer of the soil into the lower layer is not sufficient for absorption and drainage in all of the slot ways of the present draining strap. In other words, because the draining strap has an excellent rate of water absorption, use of only those draining straps having 25 to 30 lanes of drain collecting slots proves to be more than enough with respect to the sandy soil and the amount of water use in the present experiment.
The draining strap 1 of Example 1 was embedded with the reverse side thereof, that is, the side having slots 2, facing downwardly in the similar position of the container 5, and the other conditions were same as in Example 1. The container was filled with water 4500 cc and then after approximately 2 minutes and 5 seconds had passed, water flowed out from the outlet end of the draining strap. Same as in Example 1, the flow was still in the form of continuous or intermittent water column flowing out from about 2/3 of the slots 2 on the straps. To observe that the state of outflow of water is more continuous than the state in Example 1 and the rate of flow is more fast, this can be seen from the fact that when outflow of water started till the container was filled to the capacity of SOOcc and 1000cc respectively, the time t2 needed in Example 2 was shorter by a little of several of ten seconds to a few minutes than the time t 1 needed in Example 1.
It can be deduced that when the reverse side of the draining strap is used, as the upper part of the slots is closed, there is thus no communication with the air from the clearances of the sandy soil to acquire a better effect of siphonic action.
Two strips la, lb and a section of conventional drain pipe lc (diameter 2cm x length 32cm) were prepared from the draining strap 1 of Example 1. 2/3 circumferential _$_ surface of the drain pipe was provided with numerous small holes and the area of water infiltration was 70 cm=./m. Both strips of the draining strap and the drain pipe were embedded by the same inclination (1/30) in the aforesaid container 5, as shown in FIG. 7, with the draining strap 1 a facing downwardly, the draining strap 1 b facing upwardly and the drain pipe lc with the non-porous part lying below. About 2 minutes after addition of water to the full, water flowed out respectively from the draining straps la, lb and the drain pipe 1 c. Rate of flow was observed, it flows more rapidly in the draining straps 1 a, lb than the drain pipe lc. When 2 minutes after the outflow of water started, the outflow of water in the drain pipe lc decreases gradually to 3 1/2 minutes the flow of water stops. While the same outflow ofwater is still maintained in the draining straps la, lb, however, after 3 1/2 minutes the amount of outflow of water also decreases gradually form the draining strap lb till 4 1/2 minutes the outflow of water stops.
Outflow of water continues in the draining strap la till after about 30 minutes when it stops. At this time, the sandy soil was substantially saturated with water content and the water level was no longer there on the upper part of the soil.
From the foregoing result of experiments it can be seen that the draining strap of the present invention possesses a strong rate of water absorption and a drainage effect.
Accordingly, when water head pressure drops gradually there is a tendency that Infiltration water from the sandy soil infiltrates and flows gradually towards the draining straps la, lb, especially towards the side of the draining strap la that faces downwardly. It can be deduced that because the rate of water absorption in the conventional drain pipe is relatively low, the infiltration water infiltrates and flows naturally towards the draining straps where the rate of water absorption is high because of the capillary and siphonic actions, and thus causes the particle clearances in soil for infiltration and flow of the water to gradually form into waterways for the infiltration water to be readily led to the draining straps. Once such waterways are formed, most of the infiltration water will flow towards the ways thereby reducing the water head pressure, the drain pipe 1 c where absorption effect is low will stop draining, and following this will then be the draining strap lb and the draining strap la will be the last only.
It has been surprisingly found that the draining straps la, lb of the present invention are better in the water absorption effect than the conventional drain pipes, and then of the same draining straps la, lb those facing downwardly contrarily are better in the rate of water absorption then those which face upwardly. This will be described in more detail in the following by means of partially enlarged drawings of FIGS.
8(A) and 8(B). As shown in FIG. 8(A), because the notches 21 of the drain collecting slots 2 face upwardly, inevitably the sandy loam P 1 of larger particle size gradually collects on the upper part of the notches 21 causing a partial blockade in the notches.
However, since the notches extend longitudinally, unlike the general drain pipes which have individual meshes of a considerable pitch and can be easily blocked, here there are still intercommunicating notches of a considerable length or number that can absorb infiltration water by the capillary action and at: the same time encourage drainage by the siphonic action created inside the slots. The result is a much better drain absorption effect than is in a drain pipe that relies merely on the water head and the gravity of water for water flowing in and drainage. Moreover, the sandy loam P2 that enter the slots 22 from the narrow notches 21 will not block either because there the space increases abruptly and also because of the siphonic action created in the notches the sandy loam easily flows out with water.
FIG. 8(B) shows the notches 21 facing downwardly and in the condition, water flows in by the water-head pressure and the capillary effect. Since the draining strap 1 is closed on the above and also the notches 21 face downwardly, both large and small size sandy loam particles P1, P2 settle down because of the gravity and will not collect and enter the notches and block in. Only the dissolved matter enters the slots 22 and this matter dissolves in and flows out with water. Next, because the notches are very narrow, it is su~cient to support water pressure inside the slots by means of the surface tension in the stationary state and there is no back leakage. Also, as it is closed on the top surface and air can hardly come in, a vacuum state is more readily produced, which resulted in the interior of the slots by the siphonic action, the eff ciencies of water absorption and drainage, to the contrary, are better than those whose notches face upwardly.
In addition, because of the dissolved matter which is drained away uninterruptedly along with the water, it results in the crevices between the sandy loam particles to become larger thereby increasing further the rate of water infiltration in the sandy loam and also results in water mark defects or infiltration routes for water to be collected readily towards the draining straps thereby further raising the efficiency of drainage. Same experiments were performed under different conditions of soil and water volume, and at conditions with different known drain pipes, and similar results were obtained, which - 1~ ..
indicates that the draining straps or bands of the present invention is superior over the conventional drain pipes and that the straps with notches facing downwardly are better than those with notches facing upwardly or facing any of other directions.
Furthermore, when water content in the sandy loam has reached saturation and the draining strap has stopped draining, water drains away again when pressure is exerted on the sandy loam and whereby the humidity in the sandy loam drops and the hardness increases. If instead vibration is exerted, the conditions will also be the same.
Frorn the foregoing, it is clear that the drain materials of the present invention not only use the capillary action plus siphonic action in achieving a high effectiveness of water absorption and drainage, but because also the straps are formed in a flexible flat band-like structure to facilitate transportation and construction and resistance to pressure, permit gravity rolling at the condition of only a thin soil cover or without a soil cover thus making it possible a saving in the cost of construction. Also, in the above condition where the soil is saturated with water content, this soil will become liquefied and form mire if subject to gravitational pressure or rolling pressure ( such as: by vehicles, etc.).
However, using the present drain materials it is still possible to continue draining and to allow the soil to become hardened at once. The materials are therefore advantageous to construction. Besides, since the drain materials are formed of an totally impermeable plastics, they can be used as a waterproof membrane as well as a draining strap to achieve the dual purposes of preventing water from infiltrating into the inner sides of the walls of the construction while simultaneously draining away water from the soil, if the materials are attached by the flat and smooth side thereof to the side of the walls of the basement or tunnel construction which are in contact with the soil by an adhesive.
The materials are thus a novel and extensively useful drain material for use in the drainage system of the agricultural and industrial constructions.
While preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes can be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.
In accordance with this invention liquid is absorbed from soil, by capillary action, into a plurality of drain-collecting slots provided on at least one surface of a strap-like drain material embedded in the soil. The slots include a plurality of notches in the surface of the drain material which are. smaller than and extend to the slots and are sufficiently small to create a capillary effect, and the slots extend along a longitudinal direction of the drain material.
The strap-like drain material of the invention comprises a strap having a plurality of slots arranged in a spaced-apart fashion across a width of the strap and extending along a length of the strap, and a plurality of notches. Each one of the plurality of notches corresponds to one of the plurality of slots, the notches extending from the slots to a surface of the strap; each notch being sized such that the notch is capable of creating a capillary action and drawing liquid from outside the strap and into the slot corresponding to that notch.
Thus, an aspect of the invention provides a drainage method whereby the capillary action produced at the narrow crack notches of the small diameter drain-collecting slots, extending longitudinally and provided densely on the surface of the thin strap-draining materials embedded within the soil, is used to absorb water contained in the soil into the slots, and whereby the siphonic force produced by the drop of water level is used to enhance absorption and collect and discharge water from one end of the slots.
An embodiment of the invention provides a drainage method wherein notches of the drain-collecting slots of the draining materials face downwardly, and water not only enters the slots by the capillary action on the one hand, but the surface tension of water produced at the narrow notches is used to support water pressure in the slots not to leak back on the other hand. At the same time the siphoning force produced at the section of drop is used to collect and discharge water, and because of the notches facing downwardly, it is possible to effectively prevent the drawback that sand particles sink because of gravity and collect at and block the slots.
Another embodiment of the invention provides a drainage method in which a strap-draining material, having on one side densely provided with small hole diameter drain-collecting slots extending whole length along the longitudinal direction and having the notches capable of producing capillary action, is embedded between soil cover or stratum and the wall of a permeable structure such that the side with the drain-collecting slots is in contact with the soil cover or stratum while the side which is without drain-collecting slots is adjacent the wall of the structure. The water content from the soil is suctioned through the notches into the slots by capillary action, and water inside the slots is collected and discharged by the siphoning force created by the drop of water level at the two ends of the slots while at the same time, on the side which is without drain-collecting slots water from the soil is blocked from permeating into the wall of the structure.
Another aspect of the invention is the provision of a strap-like draining material capable of effectively implementing the draining method, in which the draining material is formed of a weather-resistant, thermoplastic synthetic resin into a thin sheet elongated strap body, at least one side thereof having a plurality of tiny drain-collecting slots densely arranged spaced-apart along the direction of the breadth of the strap and extending the whole length of the strap in the direction of the strap length.
Notches thereof form cracks narrow enough to create a capillary action, and inside the slots there are ditches in section of expanded small round holes to facilitate collection and discharge of the water that is absorbed into the slots.
In another aspect the invention can provide a strap-draining material which can be used as a waterproof membrane as well as a draining material in basement and tunnel constructions. Also, the side that is without drain-collecting slots can have an even and smooth surface or a plain surface having a plurality of reinforced ribs.
Alternatively, the plain surface can have a reinforcement member for enhancing resistance to soil pressure.
If preferred the side which has slots can be provided with a non-woven filter material.
Therefore, the drainage method of the invention is adapted for use in a system of soil conservation on mountain slopes, underground drainage in fruit ranges and farmlands, and drainage in road bases. It utilizes a draining strap with at least one side having a plurality of parallel-arranged small diameter drain-collecting slots extending along the length of the band and with notches in the shape of capillary cracks, which is buried in any form, preferably laid flat, within the soil layer to be drained.
By capillary action at the notches of the slots, water content in the soil is absorbed into the drain-collecting slots, and water is drawn, collected and drained through the siphoning force created by the drop of water level at the two ends or at any one section of the slot.
4a For draining materials, flexible plastic materials of PVC, PE or PP are used in forming thin sheet-like elongated strap bodies. At least one surface of the strap bodies is formed with a plurality of narrow drain-collecting ditches densely arranged spaced-apart in the direction of breadth of the strap and extending the length of the band.
An opening of the ditch is formed into capillary cracks, while the ditch portion is formed in an expanded small hole, in section. In draining materials of another form, the surface where there is no formation of drain-collecting ditches is formed in a flat and even surface, and to enhance resistance to pressure and the form protecting the draining materials, this flat surface can be provided with a U-shaped reinforcing material. Having also the function of a water-resistant membrane, the draining strap may be used in an infiltration prevention and drainage system in basement and tunnel constructions.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention will be apparent from the .
following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings:
FIG. 1 is a perspective view showing a first embodiment of the draining material of the present invention;
FIG. 2 is a perspective view showing a second embodiment of the draining material of the present invention;
FIG. 3 is a perspective view showing a third embodiment of the draining material of the present invention;
FIG. 4(A), (B) and (C) are front views showing the deformation examples of the draining material attached with a reinforcement material;
FIG. 5 is a front view showing a fourth embodiment of the draining material of the present invention;
FIG. 6 is a schematic view showing the apparatus of Examples 1 and 2 of the draining material of the present invention;
FIG. 7 is a schematic view showing the apparatus of Example 3 of the draining material of the present invention; and -$-FIG. 8(A) and (B) sow respectively the partial enlarged views of the draining material with slot portions facing upwardly and downwardly illustrating the principle of drain absorption.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of one embodiment of the draining material of the present invention, with a section cut off along the direction of its length, in which the numeral 1 represents the elongated strap draining material with a flat shape in section.
This draining material 1 is a flexible strap body made by forming of a weather-resistant thermoplastic synthetic resin, one side of which is provided with a plurality of tiny drain collecting slots 2 densely arranged spaced-apart along the direction of breadth and parallel extending whole length along the longitudinal direction. Notches 21 of the slots 2 are formed in narrow cracks sufficient to create a capillary action and are communicated inwardly with small round hole slots 22 with an expanded section.
The other side of the strap body is formed in a flat and smooth surface 3. In this manner, the entire strap body is formed in a strap of reel band having the two sides both actually of a plain surface capable of being rolled up like a bolt of cloth and cut in appropriate length for use according to need. The notches 21 are formed in inlet portions to absorb water by capillary phenomenon while the slots 22 are formed in channels for collecting and draining water, the action and principle of which will be described hereinbelow.
FIG. 2 is a second embodiment of the draining material of the present invention, in which a draining material lA is basically same as the first embodiment of a flat elongated strap body made by forming of a thermoplastic synthetic resin. However, both the upper and lower sides of the strap body are formed with drain collecting slots 2 of same construction as the first embodiment. In the present embodiment, the drain collecting slots 2 on the two sides of the draining strap lA are maintained on the same pitch and opposite to each other vertically. However, it is also possible if a vertically staggered arrangement is followed.
FIG. 3 is a third embodiment of the draining material of the present invention, where in order to enable the soft flexible draining material to have a high strength of resistance to soil pressure, there is attached to the flat and smooth surface 3 of the draining material 1 shown in FIG. 1 a reinforcement material 4 formed of a hard plastic material. In the present embodiment, the form material 4 uses simply a U-shaped ri~aterial, however, it is also possible to use, for example, a U-shaped material 4A containing inside the slot numerous ribs, or reinforcement in the form of a rectangularly shaped pipe-like member 4B or other suitable form 4C, as shown in FTGS. 4(A), (B) and (C).
FIG. 5 is a furtheF embodiment of the draining material of the present invention, whereas in the third embodiment one side of the draining material 1 is attached with a hard plastics made reinforcement form material 4 in the present embodiment, however, the reinforcement portion is formed directly integrally with the draining material 1. The reinforcement portion shown in the drawings includes several high and low ribs 41, 42 extending along the longitudinal length, it is apparent however that various modifications can be made. Next, on the one side of the foregoing draining strap I having drain collecting slots 2, if necessary, there may be coated also with a non-woven and nylon yarn as filter material.
A strip of the draining strap 1 of the first embodiment having length 35cm x breadth Scm x thickness 0.3cm with a pitch of holes l.2mm on one side thereof and a total of 40 lanes of drain collecting slots 2 with notches 21 of a breadth 0.1 Smm and slots 22 of a diameter 0.9mm was obtained. With the ode with slots facing upwardly and the inner end higher than the outer end for about 1 cm, the draining strap 1 after the inner end was sealed, was embedded on the bottom inside an acryl transparent plastics made container 5 of breadth 30cm x length 30cm x height 20cm such that the outer end of the draining strap was exposed to the outside for about Gcm as shown in FIG. 6.
Sandy soil of mud and river sand mixed in a ratio of 2 : 1 and slightly pressed to be flat and smooth was filled into the container 5 to a height of l5cm with a remaining height of Scm on the soil surface. This remaining height of Scm on the soil surface was fylled with water 30 x 30 x 5 = 4500cc and after two minutes ( depending upon the rate of water permeation in the mud), water flowed out from the outlet end of the draining strap.
Based on observation of the outflow of water, it has been found that water flows out from about 2/3 of the slots and the state of water flow appears to be in a continuous or intermittent water column of full slots. This indicates that owing to differences in density and rate of water permeation among various parts in the nature of the soil, water absorbed through the notches by the capillary phenomenon enters the sbts one after the other and partially to be collected to form a segment of water column for discharge. At _7_ this time when water column flows towards the outlet end via a drop in the water head, a vacuum suction effect is created in the rear part thereof which again brings another segment of water column of the collected water at the rear part to move forward so that a siphonic action is produced. By means of this siphonic action, water that enters the slots is continuously sucked out thereby improving further the capillary action to accomplish a high rate of water absorption and rate of drainage. That about 1/3 of the slots where there is only a small amount that flows out and the flow stops or there is no water to flow out, it is because the force of infiltration from the upper layer of the soil into the lower layer is not sufficient for absorption and drainage in all of the slot ways of the present draining strap. In other words, because the draining strap has an excellent rate of water absorption, use of only those draining straps having 25 to 30 lanes of drain collecting slots proves to be more than enough with respect to the sandy soil and the amount of water use in the present experiment.
The draining strap 1 of Example 1 was embedded with the reverse side thereof, that is, the side having slots 2, facing downwardly in the similar position of the container 5, and the other conditions were same as in Example 1. The container was filled with water 4500 cc and then after approximately 2 minutes and 5 seconds had passed, water flowed out from the outlet end of the draining strap. Same as in Example 1, the flow was still in the form of continuous or intermittent water column flowing out from about 2/3 of the slots 2 on the straps. To observe that the state of outflow of water is more continuous than the state in Example 1 and the rate of flow is more fast, this can be seen from the fact that when outflow of water started till the container was filled to the capacity of SOOcc and 1000cc respectively, the time t2 needed in Example 2 was shorter by a little of several of ten seconds to a few minutes than the time t 1 needed in Example 1.
It can be deduced that when the reverse side of the draining strap is used, as the upper part of the slots is closed, there is thus no communication with the air from the clearances of the sandy soil to acquire a better effect of siphonic action.
Two strips la, lb and a section of conventional drain pipe lc (diameter 2cm x length 32cm) were prepared from the draining strap 1 of Example 1. 2/3 circumferential _$_ surface of the drain pipe was provided with numerous small holes and the area of water infiltration was 70 cm=./m. Both strips of the draining strap and the drain pipe were embedded by the same inclination (1/30) in the aforesaid container 5, as shown in FIG. 7, with the draining strap 1 a facing downwardly, the draining strap 1 b facing upwardly and the drain pipe lc with the non-porous part lying below. About 2 minutes after addition of water to the full, water flowed out respectively from the draining straps la, lb and the drain pipe 1 c. Rate of flow was observed, it flows more rapidly in the draining straps 1 a, lb than the drain pipe lc. When 2 minutes after the outflow of water started, the outflow of water in the drain pipe lc decreases gradually to 3 1/2 minutes the flow of water stops. While the same outflow ofwater is still maintained in the draining straps la, lb, however, after 3 1/2 minutes the amount of outflow of water also decreases gradually form the draining strap lb till 4 1/2 minutes the outflow of water stops.
Outflow of water continues in the draining strap la till after about 30 minutes when it stops. At this time, the sandy soil was substantially saturated with water content and the water level was no longer there on the upper part of the soil.
From the foregoing result of experiments it can be seen that the draining strap of the present invention possesses a strong rate of water absorption and a drainage effect.
Accordingly, when water head pressure drops gradually there is a tendency that Infiltration water from the sandy soil infiltrates and flows gradually towards the draining straps la, lb, especially towards the side of the draining strap la that faces downwardly. It can be deduced that because the rate of water absorption in the conventional drain pipe is relatively low, the infiltration water infiltrates and flows naturally towards the draining straps where the rate of water absorption is high because of the capillary and siphonic actions, and thus causes the particle clearances in soil for infiltration and flow of the water to gradually form into waterways for the infiltration water to be readily led to the draining straps. Once such waterways are formed, most of the infiltration water will flow towards the ways thereby reducing the water head pressure, the drain pipe 1 c where absorption effect is low will stop draining, and following this will then be the draining strap lb and the draining strap la will be the last only.
It has been surprisingly found that the draining straps la, lb of the present invention are better in the water absorption effect than the conventional drain pipes, and then of the same draining straps la, lb those facing downwardly contrarily are better in the rate of water absorption then those which face upwardly. This will be described in more detail in the following by means of partially enlarged drawings of FIGS.
8(A) and 8(B). As shown in FIG. 8(A), because the notches 21 of the drain collecting slots 2 face upwardly, inevitably the sandy loam P 1 of larger particle size gradually collects on the upper part of the notches 21 causing a partial blockade in the notches.
However, since the notches extend longitudinally, unlike the general drain pipes which have individual meshes of a considerable pitch and can be easily blocked, here there are still intercommunicating notches of a considerable length or number that can absorb infiltration water by the capillary action and at: the same time encourage drainage by the siphonic action created inside the slots. The result is a much better drain absorption effect than is in a drain pipe that relies merely on the water head and the gravity of water for water flowing in and drainage. Moreover, the sandy loam P2 that enter the slots 22 from the narrow notches 21 will not block either because there the space increases abruptly and also because of the siphonic action created in the notches the sandy loam easily flows out with water.
FIG. 8(B) shows the notches 21 facing downwardly and in the condition, water flows in by the water-head pressure and the capillary effect. Since the draining strap 1 is closed on the above and also the notches 21 face downwardly, both large and small size sandy loam particles P1, P2 settle down because of the gravity and will not collect and enter the notches and block in. Only the dissolved matter enters the slots 22 and this matter dissolves in and flows out with water. Next, because the notches are very narrow, it is su~cient to support water pressure inside the slots by means of the surface tension in the stationary state and there is no back leakage. Also, as it is closed on the top surface and air can hardly come in, a vacuum state is more readily produced, which resulted in the interior of the slots by the siphonic action, the eff ciencies of water absorption and drainage, to the contrary, are better than those whose notches face upwardly.
In addition, because of the dissolved matter which is drained away uninterruptedly along with the water, it results in the crevices between the sandy loam particles to become larger thereby increasing further the rate of water infiltration in the sandy loam and also results in water mark defects or infiltration routes for water to be collected readily towards the draining straps thereby further raising the efficiency of drainage. Same experiments were performed under different conditions of soil and water volume, and at conditions with different known drain pipes, and similar results were obtained, which - 1~ ..
indicates that the draining straps or bands of the present invention is superior over the conventional drain pipes and that the straps with notches facing downwardly are better than those with notches facing upwardly or facing any of other directions.
Furthermore, when water content in the sandy loam has reached saturation and the draining strap has stopped draining, water drains away again when pressure is exerted on the sandy loam and whereby the humidity in the sandy loam drops and the hardness increases. If instead vibration is exerted, the conditions will also be the same.
Frorn the foregoing, it is clear that the drain materials of the present invention not only use the capillary action plus siphonic action in achieving a high effectiveness of water absorption and drainage, but because also the straps are formed in a flexible flat band-like structure to facilitate transportation and construction and resistance to pressure, permit gravity rolling at the condition of only a thin soil cover or without a soil cover thus making it possible a saving in the cost of construction. Also, in the above condition where the soil is saturated with water content, this soil will become liquefied and form mire if subject to gravitational pressure or rolling pressure ( such as: by vehicles, etc.).
However, using the present drain materials it is still possible to continue draining and to allow the soil to become hardened at once. The materials are therefore advantageous to construction. Besides, since the drain materials are formed of an totally impermeable plastics, they can be used as a waterproof membrane as well as a draining strap to achieve the dual purposes of preventing water from infiltrating into the inner sides of the walls of the construction while simultaneously draining away water from the soil, if the materials are attached by the flat and smooth side thereof to the side of the walls of the basement or tunnel construction which are in contact with the soil by an adhesive.
The materials are thus a novel and extensively useful drain material for use in the drainage system of the agricultural and industrial constructions.
While preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that changes can be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.
Claims (10)
1. A drainage method comprising the step of absorbing liquid from soil, by capillary action, into a plurality of drain-collecting slots provided on at least one surface of a strap-like drain material embedded in the soil, the slots including a plurality of notches in the surface of the drain material which are smaller than and extend to the slots and are sufficiently small to create a capillary effect, and the slots extending along a longitudinal direction of the drain material from a first point to a second point of the drain material.
2. The drainage method as defined in claim 1, wherein the the notches are on only one side of the drain material, and the method comprises a further step of orienting the drain material in the soil such that the side of the drain material having the notches faces downwardly.
3. The drainage method as defined in claim 1, wherein the the notches are on only one side of the drain material, and the method comprises a further step of arranging the drain material adjacent to construction in the soil such that the side of the drain material with the notches faces the soil and aside of the drain material without notches faces and is substantially adjacent to the construction.
4. The drainage method as defined in claim 1, comprising a further step of orienting the drain material such that the first point is higher than the second point so that a siphonic force is created by the drop in elevation from the first point to the second point and causes further absorption of water from the soil.
5. A strap-like drain material comprising a strap having a first side and second side and first and second ends, at least the first side of the strap having a plurality of slots arranged in a spaced-apart fashion across a width of the strap and extending along a length of the strap, and a plurality of notches; each one of the plurality of notches corresponding to one of the plurality of slots, the notches extending from the slots to a surface of the strap; each notch being sized such that the notch is capable of creating a capillary action and drawing liquid from outside the strap and into the slot corresponding to that notch.
6. The strap-like drain material as defined in claim 5, wherein the strap includes a flat and smooth surface on the second side.
7. The strap-like drain material as defined in claim 5, wherein the second side of the strap includes a plurality of reinforcing ribs arranged spaced-apart and extending along the length of the strap.
8. The strap-like drain material as defined in claim 5, wherein the second side of the strap includes at least one U-shaped reinforcing member.
9. The strap-like drain material as defined in claim 5, wherein the second side of the strap includes reinforcement in the form of at least one rectangular pipe-like member.
10. The strap-like drain material as defined in any one of claims 5 to 9, further comprising non-woven fiber material on the surface to which the notches extend.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP98101547A EP0933477B1 (en) | 1998-01-29 | 1998-01-29 | Drainage method and strap draining materials therefor |
| CA002229758A CA2229758C (en) | 1998-01-29 | 1998-02-17 | Drainage method and strap draining materials therefor |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP98101547A EP0933477B1 (en) | 1998-01-29 | 1998-01-29 | Drainage method and strap draining materials therefor |
| CA002229758A CA2229758C (en) | 1998-01-29 | 1998-02-17 | Drainage method and strap draining materials therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2229758A1 CA2229758A1 (en) | 1999-08-17 |
| CA2229758C true CA2229758C (en) | 2005-06-28 |
Family
ID=31947253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002229758A Expired - Fee Related CA2229758C (en) | 1998-01-29 | 1998-02-17 | Drainage method and strap draining materials therefor |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0933477B1 (en) |
| CA (1) | CA2229758C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109613208A (en) * | 2018-11-26 | 2019-04-12 | 贵州师范大学 | A kind of simulation experiment method of sloping upland gutter soil and water conservation benefit |
| CN109613209A (en) * | 2018-11-26 | 2019-04-12 | 贵州师范大学 | A kind of crop field simulation experiment method of sloping upland gutter soil and water conservation benefit |
| CN110485375A (en) * | 2019-07-25 | 2019-11-22 | 黄河勘测规划设计研究院有限公司 | Antiseepage drainage exhaust structure suitable for Wall in Plain Reservoir library basin |
| CN112227504A (en) * | 2020-10-12 | 2021-01-15 | 湖南凡工建筑工程有限公司 | Connecting device for capillary permeable and drainage belt of asphalt highway |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4246305A (en) * | 1978-03-22 | 1981-01-20 | Solentanche-Entreprise | Drainage structure and process |
| FR2473262A1 (en) * | 1980-01-14 | 1981-07-17 | Renard Patrick | Underground irrigation and drainage strip - has channels formed in plastics strip with permeable felted material on upper side for seepage |
| CA1314681C (en) * | 1989-06-22 | 1993-03-23 | Grant Mccarthy | Basewrap foundation wall insulation and drainage |
| US5511346A (en) * | 1994-08-24 | 1996-04-30 | The Dow Chemical Company | Thermoplastic foam insulation and drainage board and method of using in below-grade applications |
-
1998
- 1998-01-29 EP EP98101547A patent/EP0933477B1/en not_active Expired - Lifetime
- 1998-02-17 CA CA002229758A patent/CA2229758C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0933477A1 (en) | 1999-08-04 |
| CA2229758A1 (en) | 1999-08-17 |
| EP0933477B1 (en) | 2004-04-07 |
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