JP3051350B2 - Horizontal drain for promoting consolidation settlement of cohesive soil and method for promoting consolidation settlement of cohesive soil using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal drain for civil engineering, and more particularly, to an effective drainage of pore water discharged from cohesive soil in improvement work of soft ground, landfill work, embankment work and the like. The present invention relates to a horizontal drain disposed on an on-site bed or inside an embankment to promote consolidation settlement of the cohesive soil and stabilize an embankment body.

[0002]

2. Description of the Related Art When road work or embankment construction is carried out directly on cohesive soil containing a large amount of pore water, the above-mentioned pore water contained in the cohesive soil is imposed by embankment loads on these roads and embankments. Because the water gradually drains, the settlement of the cohesive soil occurs over a long period of time, for example, for several years or several decades, and the structure or the like may be deformed and cause serious problems. For this reason, when performing the above-mentioned work on cohesive soil containing a large amount of pore water, pore water in the cohesive soil was forcibly drained to promote the settlement of the cohesive soil and stabilized. It is necessary to start construction later.

[0003] As a method of promoting the consolidation settlement of the cohesive soil containing a large amount of pore water as described above, first, it is necessary to secure the trafficability of the heavy construction equipment, or to lay a vertical drain and load the embankment from the ground after embankment loading. A sand layer, commonly called a sand mat, is laid on the ground surface to drain incoming water. Next, a vertical drain such as a sand pile or a plastic board drain is placed vertically in the cohesive soil,
After that, the embankment is loaded to the planned height. Thereby, the pore water in the cohesive soil is guided toward the ground surface along the vertical drain, and is also guided toward the end of the sand mat through the gap in the sand mat and drained. By the above, the consolidation settlement of the cohesive soil is promoted.
The embankment may be removed after the cohesive soil has settled sufficiently.

FIG. 11 is a schematic partial cross-sectional view showing the movement of pore water in order to explain the process of consolidation settlement of the viscous soil described above. A large number of vertical drains 23
Are placed in a substantially vertical direction, and a sand mat 41 is laid on the surface of the viscous soil 21.
An embankment 22 is placed on the upper surface of the device 1. Pore water (not shown) in the cohesive soil 21 is guided toward the vertical drain 23 in a substantially horizontal direction (the direction of the arrow h in the figure) by pressure and is taken into the vertical drain 23. Next, the pore water is guided toward the surface of the viscous soil 21 along the vertical drain 23 in a substantially vertical manner (direction of arrow v in the figure), and is drained through the gap of the sand mat 41.

The vertical drain 23 includes a sand pile and a plastic board drain as described above.
Drain sand used for forming the sand pile is depleted in its resources, its quality is degraded, and its unit price is currently rising. From the viewpoint of cost, a vertical drain 23 instead of sand is desired. On the other hand, the plastic board drain can reduce the material cost, but there is a problem that pores of the filter material for water permeability formed on the surface are clogged with fine-grained soil, and the like. However, since the material is a synthetic resin made from petroleum, it is not decomposed in the ground and serves as an industrial waste when it has no useful value because it fulfills the purpose of promoting consolidation settlement of the viscous soil 21. At the same time, it may interfere with later construction work.

Therefore, Japanese Utility Model Publication No. Hei 6-34413 proposes a fiber drain using a natural material as the vertical drain 23 instead of a sand pile or a plastic board drain. According to this, after the fiber drain is poured into the cohesive soil 21 to promote the consolidation settlement of the cohesive soil 21, even if the cohesive soil 21 is left as it is, it corrodes with the lapse of time, Since it is taken into the cohesive soil 21, there is no need to collect it from the cohesive soil 21, and there is no risk of polluting the cohesive soil 21 and causing pollution. In addition, cost reduction is possible in terms of material cost.

However, at present, sand mats 41 are mostly used as horizontal drains. Since sand is used for the sand mat 41, it is difficult to reduce the amount of sand after all. There is a problem that is. In the case of the sand mat 41, in the case of construction on land, so that the thickness of 50 to 100 cm,
In the case of construction in the sea, sand is laid so as to have a thickness of about 100 cm or more, and the laid thickness varies depending on the construction accuracy, but an enormous amount of sand is required for preparing a horizontal drain.

[0008] As described above, large-scale extraction of sand is not appropriate from the viewpoint of environmental protection and economic efficiency.
Since the amount of the horizontal drain material used is enormous over the vertical drain material, the development of a new material that functions as a sand mat without using sand is desired.

Therefore, a method of using the fiber drain disclosed in Japanese Utility Model Publication No. 6-34413 not only as a vertical drain but also as a horizontal drain is conceivable, but embankment is generally formed on the horizontal drain. Considerable pressure is applied in the thickness direction of the horizontal drain, and the flow path cross-sectional area per fiber drain is small (9c
mx 0.9cm), and the pressure of the embankment crushes the water supply space, and the water supply as a horizontal drain
The drainage function is small. Further, even a plastic board drain, which is one of the vertical drain materials, has a smaller flow passage cross-sectional area per piece (about 10 cm × 0.3 cm) than the fiber drain, and has a small water guiding / draining function as a horizontal drain.

Further, in the case of a horizontal drain, it is necessary to lay the fiber over a relatively large area. Therefore, when the fiber drain as the vertical drain is used as it is as a horizontal drain, not only in terms of surface area but also in some cases, There is a problem that it is necessary to stack the sheets, a considerable number of fiber drains are used, and the construction is not easy.

[0011]

As described above, if a plastic board drain or a fiber drain conventionally used as a vertical drain is used as a horizontal drain as it is to replace a sand mat, one sheet is used. In addition to the small cross-sectional area per channel, the pressure of the embankment crushes the water supply space, and the water drainage and drainage function as a horizontal drain is small. There is a problem such as poor sex.

The present invention has been made in view of the above problems, and as a horizontal drain instead of a conventional sand mat, water conductivity is hardly impaired even when pressure is applied by embankment or the like, and has excellent water conducting and draining functions. Another object of the present invention is to provide a horizontal drain for consolidating cohesive soil, which can follow distortion deformation of the ground and can be eliminated in the ground.

[0013]

In order to achieve the above-mentioned object, a horizontal drain for accelerating consolidation settlement of cohesive soil according to the present invention comprises a plurality of string-shaped or rope-shaped cores made of palm tree fibers. Cotton comprising at least one of natural fibers such as coconut fiber, jute, hemp, palm, grass, or other fibrous vegetables between the cores. A horizontal drain having a flat shape, wherein the core material and the filler material are integrally coated with a water-permeable covering material made of burlap cloth. Is double-structured, and the widthwise end sides thereof are sewn together, and each core material is sewn at a plurality of predetermined locations with the outer jacket material in the lengthwise direction. Features.

The size of the horizontal drain of the present invention is preferably a flat plate having a width of 30 to 100 cm and a thickness of 2 to 4 cm, and at least six or more core members are used. Is preferred.

The horizontal drain of the present invention is preferably made as long as possible in the form of a flat plate, and it is preferable to take a form in which it is cut as required at the time of construction. However, it is difficult to manufacture such a long drain. In this case, a plurality of horizontal drains are connected to each other by connecting the ends of the core members of the opposing horizontal drains with a flexible joint, and the horizontal drains are integrated to achieve continuous water conduction in the length direction. Such a connected body of horizontal drains may be used.

Further, the method for accelerating consolidation settlement of cohesive soil according to the present invention comprises placing a vertical drain in a local bed of soft cohesive soil for which consolidation settlement is to be promoted, and placing the horizontal drain of the present invention on the surface of the local disc. By laying the drain connection body and loading the embankment, excess pore water in the field board is guided substantially vertically toward the vertical drain and taken in the vertical drain, and the inside of the vertical drain is substantially vertically After guiding towards the ground surface,
It is characterized in that the water is drained by being guided in the longitudinal direction of the horizontal drain.

[0017]

FIG. 1 is a schematic partial perspective view showing a horizontal drain according to an embodiment of the present invention.
FIG. 3 is a schematic partial sectional view, and FIG. 3 is a schematic partial sectional plan view. The horizontal drain 10 has, for example, a width (W) of about 30 to 100 cm and a length (L) of 200 to 100 cm.
It has a flat outer shape of about 400 cm and a thickness (H) of about 2 to 4 cm. The horizontal drain 10 has a predetermined number of parallel string-like or rope-shaped core members 11 arranged at substantially equal intervals at both ends in the width direction and an intermediate portion thereof. The plurality of core members 11 are connected to the horizontal drain 10.
Is covered with a water-permeable outer covering material 12 which forms the outer shape of the above. An appropriate amount of a cotton-like filler 13 is filled between the cores 11 to fill the voids. Further, the core material 11 is sewn to outer covering materials 12, 12 located on the front and back of the horizontal drain 10 while being sandwiched by the thread body 14. Several are lined up. The horizontal drain 10 includes the core material 11, the outer cover material 12, the filler 13, and the thread 14.

The core material 11 is usually made to have a diameter of about 3 cm, and it is preferable to use at least six or more of them. It is preferable to arrange the core materials 11 and 11 in parallel with an interval of about 12 cm from each other. preferable. The core material 11 is formed in a string shape or a rope shape as shown in FIG. According to this core material 11, water conductivity is obtained by the capillary action due to the gap between the fibers in the length direction. Also, as shown in FIG.
By combining these fibers f in a string shape or a rope shape to form the core material 11, the tensile strength of the core material 11 can be further improved. The core material 11 is not limited to the above-described twisting of the fibers f, and may be a string or a rope-shaped core material 11 made of, for example, one fiber f as long as a desired diameter can be obtained.

The jacket material 12 is a burlap cloth made of woven fibers of jute, a natural material. For example, fiber diameter 1.5 ~
2.0 mm, jute fibers having a density of 1.5 to 1.7 g / cm ³ are woven into a 3 × 3 / cm ² mesh and
By using a burlap cloth having a weight of about 650 g / m ^2, it is possible to obtain the outer covering material 12 having sufficient tensile strength and appropriate water permeability. According to the covering material 12 made of burlap, pore water in the viscous soil can be taken into the horizontal drain 10 while preventing the horizontal drain 10 from being clogged by fine-grained soil or the like. Further, since the outer cover material 12 has a double structure as shown in FIG. 5, the function as a filter for taking only the pore water into the horizontal drain 10 (hereinafter referred to as a filter property) is further improved. And the horizontal drain 10
Can be significantly improved.

As shown in FIG. 1, the ends of the horizontal drain 10 in the width (W) direction are formed by connecting the ends in the width (W) direction of the outer covering materials 12, 12 located on the front and back of the horizontal drain 10. The body 14 is sutured. As shown in FIG. 5, in the case of a continuous double-layered covering material 12, as shown in FIG. 5, the folded end portion 12 a of the burlap folded in two is overlapped with the free end portion 12 b,
This overlapping portion and a covering material portion which is an opposite side when the overlapping portion is set as one side of the horizontal drain are formed into a thread body 14.
Suture.

The material of the cotton-like filler 13 is, for example, palm tree fiber, natural fiber such as jute, hemp, palm, grass, or other fibrous vegetables. , Ie, carded cotton. According to the cotton-like filler 13, even if pressure in the thickness direction of the horizontal drain 10 is applied by embankment or the like, the upper and lower covering members 1 located between the core members 11, 11 are formed.
2 and 12 do not adhere to each other.
The cotton-like filler 13 acts as a water guide in the horizontal drain 10 while ensuring a gap for water transfer between the two.

As the thread body 14 for sewing the core material 11 to the outer cover material, a natural fiber yarn such as hemp yarn, a synthetic fiber yarn, a blended yarn or the like can be considered. The shape may be a band shape, or a string shape having an elliptical or circular cross section. The thread body 14 is used for sewing the core material 11 and the jacket material 12 together. Since the thread occupies little space in the horizontal drain 10, it is not necessarily a natural material.
It is not necessary to give much weight to the selection of the synthetic material, and any material having strength and flexibility that can withstand the suturing operation may be used.

As described above, in the horizontal drain according to the present invention, since the core material 11, the covering material 12 and the filler 13 are made of a natural material, the passage of time after burying in the ground As a result, each member is decomposed in the soil and reduced to the soil, so that it does not remain in the soil as industrial waste after becoming unnecessary after fulfilling the intended purpose.

Further, in the horizontal drain 10 of the present invention, since the jacket material 12 made of burlap has water permeability, pore water in the viscous soil is transmitted through the jacket material so that Can be captured. In addition, since the outer cover material 12 has a filter property and the outer cover material 12 has a double structure, only the pore water can permeate without permeating fine-grained soil and the like. By laying in a sludge containing a large amount, the water conductivity and drainage as a horizontal drain do not extremely decrease.

Since a plurality of cords or rope-shaped cores 11 are arranged in parallel in the horizontal drain 10 of the present invention, the shape of the horizontal drain 10 can be maintained. The thickness (H) of the core material 11 can be made substantially constant, and the core material 11 forms a certain thickness even when a load is applied in the radial direction, so that the horizontal drain 10 is embedded in the ground. At this time, the horizontal drain 10 is not completely crushed by the load of the embankment or the like, and the thickness (H) can be secured to some extent to secure the water guiding space. In addition, horizontal drain 10
Since the core material 11 is disposed at both ends in the width (W) direction of the horizontal drain 10, the both ends are not crushed by a load such as an embankment or the like. H) can be secured.

Furthermore, in the horizontal drain 10 of the present invention, since the cotton-like filler 13 is filled between the cores 11, the horizontal drain 1
Even if 0 is compressed in the thickness (H) direction, it is possible to prevent the space between the core materials 11 and 11 from being extremely crushed by earth and sand. Therefore, the horizontal drain thickness (H) between the core members 11 and 11 can be maintained to some extent, and the filler 1
3 is cotton-like and has water permeability, so that the core materials 11 and 11
An air gap to serve as a headrace can be formed therebetween. Further, since the cores 11 can be separated from each other by the filler 13, it is possible to prevent the cores 11 in the horizontal drain 10 from being shifted.

Further, since the core material 11 is sewn to the sheath material 12 by the thread body 14, the core material 11 can be prevented from being displaced in the horizontal drain 10, and the core material 1 can be prevented from shifting.
A predetermined interval between the two can be maintained. In addition, core material 1
1 can be prevented from falling out of the horizontal drain 10.

Further, the core material 11, the outer cover material 12, and the filler 1
3 are flexible, and have a length (L) direction;
Since the horizontal drain 10 can be flexible in the width (W) direction, it is possible to sufficiently cope with distortion deformation of the ground even after being buried in the soil.

As a method for manufacturing and constructing the horizontal drain 10 when the above-described horizontal drain 10 of the present invention is buried in soil, the following method examples can be considered. (1) A core material 11, an outer covering material 12, and a filler material 13 each separately wound in a roll or coil shape are separately prepared, and are combined and sewn on a carrier such as a truck at the time of construction. The horizontal drains 10 which have been continuously sewn are sequentially laid on the local board in the order of the completed amount. That is, a method of executing the construction at the same time as manufacturing the horizontal drain 10. (2) The core materials 11 are arranged in a mold imitating the outer cover material 12,
After filling the filling material 13 between the core materials 11 and 11 and arranging the covering material 12 in accordance with the mold, the mold in contact with the inner surface of the covering material 12 is pulled out and stitched at a predetermined position,
A horizontal drain 10 is made. After that, the horizontal drain is transported to the construction site by a truck or the like, and is laid on the local board. That is, a method of carrying out the construction by carrying the previously manufactured horizontal drain 10.

Although not limited to the above method,
In any case, the length (L) of the horizontal drain 10 is convenient because a longer one can be cut to a required length at the time of use. However, if the length (L) is long, it becomes bulky during storage or transportation, which may increase the cost. In such a case, it is preferable that the horizontal drains 10 are formed in a length convenient for storage or transportation, and are connected to form a horizontal drain connection body having a desired length (L).

FIG. 6 is a schematic partial side sectional view showing a state in which the horizontal drains 10 are connected in the length (L) direction. The connection of the horizontal drains 10 is performed by connecting the core members 11 in the horizontal drains 10 with the joints 15. The joint 15 shown here has a bellows structure with both ends open, and is fixed between the horizontal drains 10 with the core material 11 fitted in the ends. As a material for forming the joint 15, a plastic such as polypropylene or polyethylene, or a material having flexibility such as synthetic rubber, bamboo, natural rubber, or the like is preferable. It is also a preferable embodiment to use a recycled plastic as the plastic. .

According to the connecting body in which the horizontal drains 10 are connected as described above, it is possible to easily conduct water introduction and drainage over a wide range and a long distance without deteriorating the performance.

Next, FIG. 7 is a schematic sectional view showing an example in which the horizontal drain 10 is constructed for improving the soft ground. In the figure, reference numeral 20 denotes an on-site bed of soft cohesive soil intended to promote consolidation settlement, and reference numeral 22 denotes an embankment loaded on the on-site board 20. Vertical drains 23 are provided in the on-site board 20 in the horizontal and substantially vertical directions, and a plurality of connected bodies of the horizontal drains 10 are arranged on the surface of the on-site board 20 on the opposite side in the figure. The horizontal drains 10 are connected by a flexible joint 15 as shown in FIG. 6, for example, and are long in the length (L) direction of the horizontal drains 10 and arranged in parallel, for example, as shown in FIG. . Excessive pore water (not shown) in the on-site board 20 is guided toward the vertical drain 23 in a substantially horizontal direction (the direction of the arrow h in the figure), and is taken into the vertical drain 23. Next, the inside of the vertical drain 23 is guided toward the ground surface in a substantially vertical direction (arrow v direction in the figure), and toward the length (L) direction (arrows x and x 'directions in the figure) of the horizontal drain 10. Guided and drained. As described above, the promotion of consolidation settlement of the ground
After the material is compacted to some extent, there is no reason to bury the horizontal drain 10. Is preferably reduced.

In the above embodiment, the case where the horizontal drains 10 connected in the length (L) direction are laid in parallel on the ground surface or in the embankment is shown, but the invention is not limited to this. Without the horizontal drain 10
It may be laid in parallel, for example, on the ground surface in a state where a plurality of layers are stacked instead of one layer. In this case, it is preferable that the plurality of layers be superposed such that a substantially central portion of the upper layer horizontal drain 10 is superimposed on a connection portion between the core members 11.

[0035]

EXAMPLE The following experiment was conducted to examine the water permeability of the horizontal drain 10 according to the present invention. The details will be described below. <Experimental Example 1> First, FIG.
Permeability test (JIS A) using the device shown in the schematic sectional view of
1218). 2 pieces of burlap fabric of the outer covering material 12 have a diameter of 1
A specimen cut to a size of 1.9 cm and a sectional area of 111.2 cm ² was used as a test body. The thickness of the two burlap fabrics is 2.5 mm.

In the illustrated apparatus, the jacket 12 is attached to the lower portion of the inner cylinder 27 installed in the outer cylinder 26. When water is supplied into the inner cylinder 27 from above, while water accumulates in the inner cylinder 27, a part of the water permeates the outer cover material 12 and enters the space 28 between the outer cylinder 26 and the inner cylinder 27. It gradually accumulates. The water accumulated in the space 28 overflows from the overflow port 26a of the outer cylinder 26. On the other hand, the inner cylinder 27 has an overflow port 27 at a position above the overflow port 26a.
a, and the water accumulated in the inner cylinder 27 is
It flows outward from 7a. When the difference between the height of the overflow port 27a and the height of the overflow port 26a is set to a certain value, the water pressure applied to the jacket material 12 becomes constant. The position difference between the overflow port 27a and the overflow port 26a is the head difference Δh. A permeability test was conducted by changing the head difference Δh by several types.

The water permeability (k) is obtained by the following equation (1). <Equation 1> k = q / (iA) = q / ｛(Δh / t)
A｝ q: Water flow rate per unit time (cm ³ / sec) i: Hydraulic gradient (i = Δh / t) Δh: Head difference t: Thickness of jacket material 12 A: Cross-sectional area of inner cylinder 27 (Cross-sectional area of jacket material 12)

Table 1 below shows the results of calculating the difference in height between the overflow ports 26a and 27a, that is, the coefficient of permeability (k) when the head difference (△ h) was changed.

[0039]

[Table 1]

As is apparent from Table 1, the water permeability of the jacket material 12 (two pieces of jute fabric) at a constant water temperature of 15 ° C. is k ₁₅ =
The range was 1.5 × 10 ^{−1 to} 2.3 × 10 ⁻¹ (cm / s). This is 100 to 100 times higher than the permeability coefficient k = 1.0 × 10 ⁻³ (cm / s) of a commonly used sand mat.
The value is about 200 times larger, which indicates that the jacket material 12 has a sufficient water passage capacity.

<Experimental Example 2> Next, in order to investigate the water flow performance in the length direction of the horizontal drain 10 according to the embodiment, the following experiment was carried out using an apparatus shown in a schematic sectional view of FIG. Was done. The test method conforms to the water permeability test (JIS A 1218).

In Experimental Example 2, a horizontal drain 10 manufactured under the following conditions was used as the object to be measured. Core material 11 Material: Palm fiber Size: Diameter 3 cm Form: Rope number: 9 Outer covering material 12 Material: Burlap fiber Size: 98 cm in width x 0.2 cm in thickness x 200 cm in length (up and down 2 pieces) : Fiber woven fabric (weight: 600 g / m ² , density: 61 × 32/10 cm square) Filler 13 Material: coarse carded burlap fiber Form: flocculent Usage: 8 kg / sheet The size of the horizontal drain 10 used in the test The width is 40cm
× Thickness 3.8 cm × Length 100 cm, cut out from the product shown above.

In the apparatus 30 shown in FIG. 10, the horizontal drain material 10 to be measured is wrapped in the rubber films 29b and 29c and set in the apparatus. First, the lower lid 32 is attached via the rubber film 29d, and The gap between the device and the horizontal drain 10 is filled with sand 31a, 32a, and the upper lid 31 is attached via the rubber film 29a. The upper lid 31 and the lower lid 32 are connected to a compressor 35 via a pressure gauge 33 and a regulator 34.
Is connected to The regulator 34 applies a predetermined air pressure to the rubber film 29a on the upper lid 31 and the rubber film 29d on the lower lid 32, and applies a predetermined vertical pressure to the horizontal drain 10 sandwiched between the sands 31a and 32a. It has become. In addition, the device 30 includes the horizontal drain 1
Water tanks 36 and 37 connected to both end portions of the “0” are provided. In this device 30, for example, water supplied from a water tank 36 flows from one side end of the horizontal drain 10 to the other side end, and the water that escapes is collected in a water tank 37. I have. The difference between the water levels of the water tanks 36 and 37 is the head difference (△ h).

The vertical pressure (kgf) from the upper lid 31 and the lower lid 32
/ Cm ² ) and the water flow performance of the horizontal drain 10 when the hydraulic gradient i was changed are shown in Table 2 below.

[0045]

[Table 2]

As is clear from Table 2, the vertical pressure σ _v =
In the range of 0.5 to 2.0 (kgf / cm ² ), the hydraulic conductivity in the length (L) direction of the horizontal drain 10 is k ₁₅ = 5.0 ×
It was 10 ^{−2 to} 1.3 × 10 ⁻² (cm / s).

As described above, the permeability of a commonly used sand mat is about k = 1.0 × 10 ⁻³ (cm / s), and the permeability in the longitudinal direction of the horizontal drain 10 according to Experimental Example 2 is as follows. Is 10 to 50 times larger than this, indicating that it has a sufficient water flow capacity.

<Experimental Example 3> In order to obtain the same water permeability as the horizontal drain 10 according to the present embodiment using the fiber drain described in Japanese Utility Model Publication No. 6-34413, how many fiber drains are required? The following calculation was made in order to investigate

The conditions for the trial calculation are shown below. Fiber drain size: width 90 ± 15 mm, thickness 9 ± 1.5 mm Permeability: k _a = 1 × 10 ⁻¹ cm / s at _a constraint pressure of 0.5 kgf / cm ^{2 At} _a constraint pressure of 2.0 kgf / cm ² k _a = 1 × 10 ⁻² cm / s Size of the horizontal drain 10: width 90 cm, thickness 3.8 c
m Permeability: in at confining pressure _{^{0.5kgf / cm 2 k b = 5}} × 10 -2 cm / s confining pressure _{^{2.0kgf / cm 2 k b = 1.3}} × 10 -2 cm
/ S

At a confining pressure of 2.0 kgf / cm ² , the amount of water flow q in the cross section of the horizontal drain 10 is calculated according to the following formula. (Under the conditions of the same hydraulic gradient _{i) q = A × k b} × i = 90 × 3.8 × 1.3 × 10 -2 × i
= 4.45 × icm ³ / s Thus, the number of fibers drain corresponding thereto is determined by the following calculation. _{A = q / k a × i} = 4.45 × i / 1 × 10 -2 × i = 4
45cm ² sheets x = 445/9 × 0.9 ≒ 55 sheets

As is apparent from the above formula, in order to obtain the same drainage capacity as one horizontal drain, 55 fiber drains need to be stacked in the horizontal or vertical direction. Practically, it is difficult to perform such an operation in terms of cost and workability, and from this, the usefulness of the horizontal drain 10 is apparent.

[0052]

As described above in detail, according to the horizontal drain according to the present invention, pore water in the soil is guided into the horizontal drain through the covering material, and the water is disposed in the horizontal drain. Is guided in the longitudinal direction of the horizontal drain.
After that, the water is drained from the longitudinal end of the horizontal drain.

Since the jacket material has water permeability, the pore water can be easily taken into the horizontal drain. Further, since the outer cover material is made of burlap cloth, it has a high filter property, and can transmit only pore water in the soil without clogging and without allowing fine-grained soil or the like to pass. As the jacket material, for example, a fiber diameter of 1.5 to
2.0 mm, jute fibers having a density of 1.5 to 1.7 g / cm ³ are woven into a 3 × 3 / cm ² mesh and
By using a burlap cloth having a weight of about 650 g / m ² , a covering material having sufficient tensile strength and having both appropriate water permeability and good filter performance can be obtained. In addition, since the outer cover material is formed in a double configuration, the filter performance can be further improved, and the strength of the horizontal drain can be significantly improved.

Further, since the core material is arranged in parallel in the horizontal drain, the shape of the horizontal drain can be stabilized, and the horizontal drain can be prevented from being extremely collapsed even by a load due to embankment or the like. it can. Further, since the core material is sewn to the jacket material at a plurality of locations in the length direction, it is possible to cope with distortion deformation of the ground.

Further, since the filler is filled between the cores, the maintenance of the thickness of the horizontal drain between the cores is assisted. In addition, the filler has a water permeability because it is cotton-like. Therefore, the water taken in the horizontal drain can be smoothly guided in the length direction of the horizontal drain through the core material, the gap formed between the core materials, and the filler. Further, the width in the width direction between the cores can be maintained, and the cores in the horizontal drain can be prevented from being shifted. Further, since the core material is obtained by combining fibers in a string shape or a rope shape, the strength can be further improved.

Thus, when the horizontal drain according to the present invention is used for landfill construction, embankment construction, etc., pore water in the soil is effectively drained to quickly remove soft cohesive soil or embankment. Can be stabilized. In addition, water permeability is hardly impaired even by pressure of an embankment or the like, and has a followability to distortion deformation of the ground. Furthermore, since it is not necessary to use sand, it is possible to contribute to environmental conservation and to reduce material costs.

In addition, the horizontal drain of the present invention has a core material of palm tree fiber, a sheath material of burlap cloth, and a filler material of palm tree fiber, jute, hemp, palm, grass, or other fibrous materials. Made of natural fibers such as vegetables, it is possible to use inexpensive imported materials, etc., so that the cost of raw materials can be reduced, and after laying on the ground to drain underground, Even if it is left buried in the ground, it will be decomposed in the soil with the passage of time, so there is no need to collect it later, which is reasonable, and there is no danger of polluting the ground and generating pollution.

Further, if the end faces of the opposing core members are connected by a flexible joint and the opposing horizontal drains are integrated into a horizontal drain integrated body,
Water can be continuously introduced in the length direction. Therefore, it is possible to freely cope with the surface area required at the time of embedding.

[Brief description of the drawings]

FIG. 1 is a schematic partial perspective view showing a horizontal drain according to an embodiment of the present invention.

FIG. 2 is a schematic partial cross-sectional view showing a horizontal drain according to the embodiment.

FIG. 3 is a schematic partial cross-sectional plan view showing a horizontal drain according to the embodiment.

FIG. 4 is a schematic enlarged side view of a core material.

FIG. 5 is a schematic cross-sectional view showing a horizontal drain according to the embodiment.

FIG. 6 is a schematic partial cross-sectional view showing a state where horizontal drains according to the embodiment are connected to each other.

FIG. 7 is a schematic cross-sectional view showing a construction example using the horizontal drain according to the embodiment.

FIG. 8 is a schematic partial plan view showing a state where horizontal drains according to the embodiment are connected to each other.

FIG. 9 is a schematic cross-sectional view showing an apparatus used in an experimental example in the embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view showing an apparatus used in an experimental example in another embodiment.

FIG. 11 is a schematic cross-sectional view for explaining a process of consolidation settlement of a conventional soft ground.

[Explanation of symbols]

10: horizontal drain, 11: core material, 12: jacket material,
13: filler, 14: thread, 15: joint, 2
0: local board, 22: embankment, 23: vertical drain,
26: outer cylinder, 26a: overflow, 27: inner cylinder, 27a: overflow, 28: space, 30: device,
31: upper lid, 32: lower lid, 33: pressure gauge, 3
4: Regulator, 35: Compressor, 3
6, 37: Aquarium

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Inoue 2- 15-3 Higashino, Asaminami-ku, Hiroshima City (72) Inventor Toshio Aboshi 3-58 Takasu, Nishi-ku, Hiroshima City (56) Reference Hei 5-3346 (JP, U) Japanese Utility Model Showa 51-6705 (JP, U) Japanese Utility Model Hei 6-34413 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 3 / 00 E02D 3/10

Claims (5)

(57) [Claims] 1. A plurality of string-shaped or rope-shaped core members made of palm tree fibers are provided at both ends in the width direction and at an intermediate portion thereof.
The parallel arrangement, the fibers of palm trees between the core material, jute,
Natural fibers such as cannabis, palm, grass or other fibrous vegetables
A cotton-like gap filler made of at least one of fibers is disposed, and the plurality of cores and fillers are made of burlap.
A horizontal drain which is integrally covered with a water-permeable outer cover material and has a flat plate shape, wherein the outer cover material has a double structure.
And the edges in the width direction are stitched together.
Rutotomoni, viscous each core material, characterized in that it is stitch at said outer covering material and a plurality of predetermined locations along its length
Horizontal drain for accelerating consolidation settlement of porous soil . 2. The horizontal drain for accelerating consolidation settlement according to claim 1 , wherein the horizontal drain is formed in a flat plate shape having a width of 30 to 100 cm and a thickness of 2 to 4 cm. 3. Use of at least 6 or more core materials
A horizontal drain for accelerating consolidation settlement of cohesive soil according to claim 1 or 2 . 4. The horizontal drain according to claim 1 , wherein ends of the core members of the horizontal drain facing each other are connected to each other by a flexible joint. A continuous body of horizontal drains, wherein continuous connection of water in the length direction is achieved. 5. A weak viscous material which promotes consolidation settlement
A vertical drain is installed in the soil base and the surface
A series of horizontal drains according to any one of claims 1 to 3.
By laying the union and loading the embankment, the excess
The large pore water to the vertical drain in a substantially horizontal direction
Take in the vertical drain, and place inside the vertical drain on the ground surface
Guide in a substantially vertical direction toward the horizontal drain
Drains pore water in cohesive soil by guiding it toward
A method for promoting consolidation settlement of cohesive soil.