JP2659697B2 - Drain material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drain material used in a drain construction method for strengthening the ground by draining water in a soft ground efficiently to the ground surface in a short time.

[0002]

2. Description of the Related Art A drain construction method, which is one of the soft ground improvement methods, is to drive a belt-shaped drain material wound in a roll shape into the ground by using a dedicated driving machine, and to form the drain material. It is a method of removing the water contained in the ground at an early stage by the water permeation effect and stabilizing the ground. This drain method is widely used as an economical consolidation promotion method in land improvement work on land. .

As a drain material used in the drain method, for example, as shown in FIG. 11, a polyethylene is formed by bending a corrugated shape between two nonwoven fabrics (water-permeable materials) 1 and 1 'which are spaced apart from each other. The one in which a base material 2 made of a synthetic resin such as the above is interposed is known. Nonwoven fabric having water permeability 1, 1 '
The water in the ground that has passed through the
The water is discharged to the ground surface through the water passage 3 surrounded by. As the shape of the water passage, a water passage 3 'having a wave shape as shown in FIG. 12 is also known. In these corrugated waterways, the cross-sectional area per waterway is large, but the cross-sectional modulus increases due to the use of materials, and the possibility of bending due to the curvature of the drain caused by the subsidence of the ground increases. Become. In order to avoid this, a water channel 3 ″ having a double-sided groove shape as shown in Fig. 13 is used. With the double-sided groove shape, it is possible to suppress bending, but 1 is not uniform,
As shown in FIG. 4 (a), the drain material 4 has a large curve and a small curve with respect to the ground surface G depending on the location, and the interval between the adjacent drain materials 4 in the depth direction (arrow D). Become irregular. Since the time required for consolidation of the ground is governed by the maximum value of the interval between the drain members 4, it takes a lot of time to consolidate the portion where the drain member 4 deforms irregularly. In addition, the double-sided groove-shaped one has a smaller cross-sectional area per one water passage than the corrugated one, and the drainage efficiency may slightly decrease as the water-passing distance increases.

Further, as a method of draining when a cross section of a water passage is reduced due to crushing or clogging due to earth pressure in a certain water passage, a cut is made in an adjacent water passage wall to connect the water passage with each other. As shown in the figure, “a groove member 5 is interposed between two nonwoven fabrics 1 and 1 ′, and a plurality of cuts 6 are formed at predetermined intervals in the longitudinal direction of the groove member 5 so that an adjacent water passage is formed. What can be communicated (refer to Japanese Patent Publication No. 3-57245) is known. In the structure shown in FIG. 15, since the adjacent water passages communicate with each other, even if a certain water passage is closed, the water moves to the adjacent water passage, so that the draining operation is not interrupted at all. However, the water is not smoothly moved between the adjacent water passages because the cut is simply made. Moreover, the method shown in FIG. 15 cannot suppress the irregular curvature of the drain material.

Accordingly, as shown in FIG. 16, the applicant of the present invention has stated that “on both sides of a flat substrate 7 interposed between two nonwoven fabrics 1 and 1 ′ spaced apart from each other and substantially parallel to the longitudinal direction. A large number of rib plates 8 are integrally formed, each of which has a plurality of water passages 9 surrounded by the rib plates 8 and the nonwoven fabrics 1 and 1 'and the substrate 7, and a nonwoven fabric is formed from a portion of the rib plate 8 which is in contact with the nonwoven fabric 1. The invention relating to "a drain material in which a narrow groove-shaped opening 10 is provided over a portion in contact with 1 '" has been filed. (6-30218
According to this drain material, even if the drain material is long, the drainage resistance is small, the water does not bend into an irregular shape in the soil, and the water moves smoothly between the water passages. However, providing a part of the opening that extends over the front and back of the rib plate requires a high level of manufacturing technology and increases the cost.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to discharge water in soft ground to the ground surface in a short period of time and quickly consolidate the ground. An object of the present invention is to provide a low-cost drain material that can be strengthened.

[0007]

In order to achieve the above object, the gist of the present invention is to provide a large number of protrusions substantially parallel to the longitudinal direction on both the front and back surfaces of a flat substrate between two water-permeable materials facing each other. In a drain material having a plurality of water passages surrounded by a ridge rib, a water permeable material and a substrate, a notch communicating with the adjacent water passages is provided by interposing a core material integrally formed with the ribs. The drain material is characterized in that a range (hereinafter referred to as a “notch zone”) provided in the ridge rib and a range not provided (hereinafter referred to as a “normal zone”) are alternately provided in the length direction of the drain material. In the first invention, a drain material characterized in that the width of the notch provided in the ridge rib is substantially the same as the width of the water passage, as the second invention, In the invention, the length of the notch zone is set to 1 In this case, the drain material characterized in that the length of the normal zone is between 0.5 and 3 is the third invention. In the third invention, the arrangement of the notches in the notch zone is as follows: A fourth aspect of the present invention is a drain material characterized in that it is wide in the width direction at the center of the notch zone, narrows toward the normal zone, and converges to the center of the width.

[0008]

[Function] Since the notch zone and the normal zone constitute one cycle and are provided repeatedly in the length direction, after extruding the flat substrate, a rib plate portion having an outer peripheral length of an integral multiple of one cycle is formed on a forming roll. By simply passing the core material, a core material in which the notch zone and the normal zone are alternately provided can be easily obtained. Then, even if a part of the water passage is clogged, the notch can reliably secure the water passage, and can smoothly drain the water.
When the width of the notch is substantially equal to the width of the water passage, clogging of the notch does not occur, communication between adjacent water passages is ensured, and drainage can be performed more smoothly. In addition, since the cutout zone and the normal zone are provided alternately so that the rigidity of the drain material is repeatedly changed at regular intervals in the length direction, the curvature of the drain material in the soil is less likely to be irregular. However, if the length of the normal zone is shorter than 0.5 when the length of the notch zone is set to 1, the rigidity of the entire drain material decreases, and as shown in FIG. When the normal zone length is longer than 3.0, the curve in the soil becomes too large and the variation in drainage distance becomes large, resulting in a delay in consolidation settlement. Therefore, the ratio of the length of the normal zone to the length of the notch zone is 0.5 to 3.
The range of 0 is preferable, and the range of 1.0 to 2.0 is more preferable. In addition, the arrangement of the notches in the notch zone is wider in the width direction of the drain material in the center part of the length, the number of notches is large, the distribution narrows toward the normal zone, and converges to the center in the width direction. As a result, the change in rigidity from the notch zone to the normal zone becomes gentle, buckling in the soil hardly occurs, and the curved state is stabilized.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. A belt-like plate made of polyethylene is extruded and passed between a pair of forming rolls provided immediately thereafter to form ridge ribs (11 in FIG. 1) extending substantially parallel to the longitudinal direction on both front and back surfaces, and at the same time, the following description The notch zones (13 in FIG. 2 (a) and FIG. 3) and the normal zones (14 in FIG. 2 (a) and FIG. 3) are alternately arranged in an arrangement as shown in FIG. 2 (a) or FIG. A core material was obtained in which the notches (12 in FIG. 1) were wide and distributed over the entire width at the center of the notch zone, narrowed toward the normal zone, and converged at the center of the width.
Next, a nonwoven fabric (1, 1 in FIG.
1) was laid on the tip of the ridge rib and welded by a pair of heat rolls to form a number of water passages (9 in FIG. 1), thereby obtaining the drain material shown in FIG. To further explain FIG. 1, two long synthetic fiber nonwoven fabrics (water-permeable materials) 1 and 1 ′ having a thickness of 0.3 mm and a width (W-W direction) of about 97 mm are about 3 mm.
A polyethylene core in which 33 protruding ribs 11 are integrally formed between the two non-woven fabrics so as to be substantially parallel to each other in the longitudinal direction between the two nonwoven fabrics. 32 water passages 9 (width 2 mm on the substrate side) surrounded by the ribs 11, the nonwoven fabrics 1, 1 ′, and the substrate 7
× 1.3 mm in height) are formed in two rows above and below the substrate. A plurality of notches 12 (width 2 mm × depth 0.7 mm) are provided at substantially constant pitch in the longitudinal direction (arrow L) in the protruding ribs 11 formed on both surfaces of the flat substrate 7.
The notch 12 does not necessarily need to be provided on all protruding ribs on the same line (KK), and may be provided so that adjacent water passages communicate with at least one location in the notch zone. The shape of the notch 12 may be a semicircle or a rectangle. The width of the notch 12 is substantially the same as the width of the water passage 9, and the depth of the notch 12 is preferably ２〜 to ／ of the rib height.

FIGS. 2A and 3 show examples in which the arrangement of the notches in the notch zones is different. In each case, the notch zones 13 and the normal zones 14 are provided alternately. At the center of the length of the cutout zone 13, the cutouts are wide in the width direction of the drain material, and the number of the cutouts is distributed in large numbers. The distribution becomes narrower toward the normal zone 14 and converges to the center in the widthwise direction. (Figure 2
(A), the bold line in FIG. 3 indicates the portion where the notch exists). The arrangement of the notches in the notch zone 13 in the case of FIG. 2A is rhombic when viewed from above, and it is elliptical when viewed from above in FIG. The length of the notch zone in FIGS. 2A and 3 is 240 mm, and the length of the normal zone is 43 mm.
At 0 mm, the ratio of the length of the notch zone to the length of the normal zone is 1:
1.79. In this case, the pitch P in the length direction at the position where the notch is provided is the same (15 mm), but may be different. In addition, it is preferable to shift the position of the notch 12 on the front and back in the longitudinal direction (arrow L) as shown in FIG. 1 from the viewpoint that buckling hardly occurs in the soil.

As shown in FIG. 2 (b), the drain material of the present invention (notch width = 2.5 mm, depth = 0.7 m) in which notch zones 15a and normal zones 15b are alternately provided.
m, P = 10 mm, notch zone length = 70 mm, normal zone length = 80 mm, notches displaced by about 5 mm on both sides) and no notches as shown in FIG. For the conventional drain material, an experiment was performed on the deformation and drainage effect in the soil by the following method.

As an experimental device, as shown in FIG. 4, a cylindrical consolidation tester having a height (H) of 35.5 cm and an inner diameter (D) of 33 cm was used. 4, 16 is a compressed air port, 17 is a drain port, 18 is a piston, 19 is a sand layer,
Reference numeral 20 denotes a vinyl sheet, 21 denotes clay, 22 denotes a drain material (having a thickness of 3.6 mm and a width of 3 cm), 23a and 23b detents for the drain material, 24 a displacement gauge, and 25 a strain gauge. FIG. 5 is an enlarged view showing an attached state of the drain member 22 to the upper and lower stoppers 23a and 23b. As the clay, a seabed clay adjusted to a water content of 110 to 130% is used, and the compressed air pressure is 0.5 to 1.0 kgf / cm.
^The loading was performed with the goal of producing a compression strain of about 26 to 30%. After the consolidation was completed, the drain material was dug out, the curved shape was observed, and the water content around the drain material was investigated.

FIG. 6 shows the curved shape of the drain material according to the present invention, which is deformed right and left in the depth direction at substantially the same rate. As shown in FIG. It is greatly curved only on one side with respect to the vertical direction.

FIG. 8 is a diagram showing a position where the water content is investigated in the apparatus shown in FIG. 4, wherein the inner diameter d ₁ is 13 cm and d ₂ is 23 cm. 8A is a plan view, FIG. 8B is a cross-sectional view taken along the line XX of FIG. 8A, and FIG. 8C is a cross-sectional view taken along the line YY of FIG. 8A. . The distribution of the water content when the drain material of the present invention is used is as shown in FIG. 9 and the average water content is about 52%, but the average water content when the conventional drain material shown in FIG. 10 is used. 10% or more lower than about 66%. Further, the variation in the water content ratio at each position in the depth direction is within about 9% in the case of the present invention in FIG. 9, but reaches about 14% in the conventional case in FIG. That is, by using the drain material of the present invention, the drain material can be curved almost regularly in the depth direction and can be drained smoothly.

In the drain material of the present invention, the notch zone and the normal zone are arranged at regular intervals in the length direction of the drain material. Therefore, when the material is driven into the soil, the driving tool is provided with an ultrasonic device or the like. Then, by detecting the notch zone, the driving depth and the position in the soil can be known.

[0016]

According to the present invention, it is possible to provide a low-cost drain material capable of discharging water in soft ground to the ground surface in a short period of time and rapidly strengthening the consolidation of the ground.

[Brief description of the drawings]

FIG. 1 is a perspective view in which a part of a drain material of the present invention is cut away.

FIG. 2A is a plan view showing the arrangement of a cutout zone of a drain material of the present invention and a normal zone, and FIG. 2B is a cutaway zone of a drain material of the present invention used in an experiment and a normal zone; It is a top view showing arrangement of a zone.

FIG. 3 is a plan view showing another arrangement of the cutout zone and the normal zone of the drain material of the present invention.

FIG. 4 is a side sectional view of a consolidation tester.

5 is a view showing a state in which a drain material is attached to upper and lower stoppers of the consolidation tester of FIG. 4;

FIG. 6 is a diagram showing a state of deformation of the drain material of the present invention in the depth direction by a consolidation test.

FIG. 7 is a diagram showing a state of deformation of a conventional drain material in a depth direction by a consolidation test.

8A and 8B are diagrams for explaining a position where a moisture content is investigated in a consolidation test. FIG. 8A is a plan view, and FIG.
FIG. 8A is a sectional view taken along the line XX of FIG. 8, and FIG. 8C is a sectional view taken along the line YY of FIG.

FIG. 9 is a diagram showing the distribution of the water content in the depth direction in a consolidation test when the drain material of the present invention is used.

FIG. 10 is a diagram showing the distribution of the water content in the depth direction in a consolidation test when a conventional drain material is used.

FIG. 11 is a perspective view in which a part of a conventional drain material having a corrugated water passage is cut away.

FIG. 12 is a cross-sectional view of another conventional drain material having a corrugated water passage.

FIG. 13 is a perspective view in which a part of a conventional drain material having a water passage having a double-sided groove shape is partially cut away.

FIG. 14 (a) is a schematic diagram showing a state of curvature of a conventional drain material in the depth of the ground, and FIG. 14 (b) is a view showing a state of curvature of the drain material of the present invention in the depth of the ground. It is a schematic diagram.

15 (a) is a cross-sectional view of a conventional drain material having cuts, and FIG. 15 (b) is a ZZ of FIG. 15 (a).
It is arrow sectional drawing.

FIG. 16 is a partially cutaway perspective view of a conventional drain material having a narrow groove-shaped opening.

[Explanation of symbols]

 1, 1 '... non-woven fabric 2, 2' ... substrate 3, 3 ', 3 ", 9 ... water passage 4, 22 ... drain material 5 ... groove material 6 ... cut 7 ... substrate 8 ... rib plate 10 ... opening 11 ... Ridged rib 12 ... Notch 13 ... Notch zone 14 ... Normal zone

Claims (4)

(57) [Claims] 1. A core member integrally formed with a plurality of ridge ribs substantially parallel to a longitudinal direction on both front and back surfaces of a flat substrate between two opposing water permeable materials. In a drain material having a large number of water passages surrounded by a rib, a water-permeable material, and a substrate, a notch communicating with the adjacent water passage is provided on the protruding rib and a range not provided is defined by a length of the drain material. A drain material provided alternately in the direction. 2. The drain material according to claim 1, wherein the width of the notch provided in the ridge rib is substantially equal to the width of the water passage. 3. The length of a range in which a notch is not provided is 1 to 3 when the length of a range in which a notch is provided in a ridge rib is 0.5 to 3. 3. The drain material according to 1 or 2. 4. The arrangement of the notch in the area where the notch is provided in the protruding rib is wide in the width direction at the center of the area where the notch is provided, becomes narrower toward the area where the notch is not provided, and has a width center. 4. The drain material according to claim 3, wherein the drain material converges.