JPH11247172A - Drain material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To successively detect height positions of drain material in underground, and know the accurate driving depth by interposing a part to be detected (copper-based metal mesh piece) at constant intervals in the longitudinal direction between the core material and permeable material of the drain material. SOLUTION: Drain material mutually oppositely disposes two long polyethylene-made non-woven fabrics 21, 21' by separating them from each other at a prescribed interval, and a polyethylene-made core material forming a projection rib 23 on both the faces of a flat plate-like base plate 22 is interposed between the two non-woven fabrics. Thirty four water passages 24 surrounded by the projection rib 23, the non-woven fabrics 21, 21' and a flat plate base plate 22 are formed by sandwiching the base plate vertically. A number of notches 25 are provided on the projection rib 23 formed on both the faces of the flat plate-like base plate at pitches of 15 mm in the longitudinal direction, and prescribed brass-made mesh pieces 6 (for instance, 200 meshes) are interposed between the projection rib 23 of the core material and the non- woven fabric 21 every 1 m in the longitudinal direction in the center of the width direction of the drain material.

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 method for draining water in a soft ground to a ground surface in a short period of time so as to strengthen the ground.

[0002]

2. Description of the Related Art The drain construction method, which is one of the soft ground improvement methods, is to drive a belt-shaped drain material wound into a roll into the ground with a special driving machine, and to form the drain material. This drainage method is a method that removes the water contained in the ground early by stabilizing the ground by its water permeability, and this drain method is widely used as an economical consolidation promotion method in ground improvement work on land. .

As the drain material used in this drain method, for example, as shown in FIG. 4, polyethylene is bent into a wave shape between two nonwoven fabrics (water permeable materials) 21 and 21 ′ which are spaced apart from each other. 28 made of synthetic resin such as
Is known. Nonwoven fabric 2 having water permeability
The water in the ground that has passed through 1, 21 '
The water is discharged to the ground surface through a water passage 29 surrounded by 21 'and the base material 28. As a shape of the water passage, a wave-shaped water passage 29 'as shown in FIG. 5 is also known. According to these corrugated water passages, the cross-sectional area per water passage 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 material caused by the subsidence of the ground increases. Become. In order to avoid this, a structure having a water channel 29 ″ in the form of a double-sided groove as shown in Fig. 6 has been used. As shown in FIG. 8A, the drain material 30 has a large curved portion and a small curved portion with respect to the ground surface G depending on the location, and as shown in FIG.
Are irregular in the depth direction (arrow D). Since the time required for consolidation of the ground is governed by the maximum value of the interval between the drain materials 30, it takes a lot of time to consolidate the part where the drain material 30 deforms irregularly.

[0004] Further, as a method for drainage in the event that the cross-sectional area of a water passage is reduced due to crushing or clogging of a certain water passage due to earth pressure, a cut is made in a wall of an adjacent water passage to connect the water passage with each other. As shown in FIG.
A groove 31 is interposed between 1, 21 ', and a plurality of cuts 32 are formed at predetermined intervals in the longitudinal direction of the groove 31,
An adjacent water channel can be connected (Japanese Patent Publication No. 3-57)
No. 245) is known. In the configuration shown in FIG. 7, 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. In addition, the method of FIG. 7 cannot suppress the irregular curvature of the drain material.

By the way, in a general drain construction method, if the driving condition of the drain material cannot be confirmed, the drain material is pulled up together with the driving tool when the driving tool is pulled out after driving the drain material into the ground. When the construction failure such as the rising phenomenon or the breakage of the drain material occurs, it is not possible to take an appropriate countermeasure of re-driving the drain material, so that the intended drain effect may not be obtained. In this case, it is not possible to know the actual driving situation simply by measuring the length of the drain material sent into the ground, and some kind of detection means is required.

In view of the above, detection portions are formed in advance at equal intervals in the longitudinal direction of the drain material, and detection means for reacting to the detection portion is provided at the end of the driving tool. After the driving, a method is employed in which the height of each detected portion of the drain material is successively detected by the detecting means when the driving tool is pulled out. For example, in Japanese Utility Model Publication No. 1-8583, a magnetic material, a printed mark, a slit, a punch or a notch is formed in the filter layer or the core of a drain material composed of a core and a pair of filter layers sandwiching the core. A drain material to be detected is disclosed. Also,
Japanese Patent Publication No. 2-27486 discloses a drain material provided with a detected part made of a metal plate on the surface or inside of the drain material. Further, Japanese Patent Publication No. 2-29806 discloses a drain material comprising a substrate and a water-permeable sheet, wherein a detection piece of a circular thin metal plate is interposed between the substrate and the water-permeable sheet.

However, there is a problem that the drainage performance is deteriorated in the detected portion because the magnetic material, the printed mark, the metal plate, and the circular metal thin plate which are the detected portion described in the above-mentioned publication have no water permeability. . In addition, when the detected part is a metal plate, the detected part lacks flexibility, so that the detected part may be formed with an irregular curve during compaction.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to discharge water in soft ground to the ground surface in a short time to quickly consolidate the ground. It is a drain material that can be strengthened, and it can detect the installation situation such as the depth at the time of driving into the ground and the presence of rising, and has a detected part with good drainage performance and flexibility Another object of the present invention is to provide a drain material that is regularly curved during compaction.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a flat substrate provided with a plurality of ridged ribs substantially parallel to the longitudinal direction on both front and back surfaces of a flat substrate. In the drain material that is interposed between the ends of the ridge ribs and the water-permeable material, by interposing copper-based metal mesh pieces at regular intervals in the longitudinal direction between the core material and the water-permeable material, The height of each detected part (copper-based metal mesh) of the underground drain material by the detecting means provided on the driving tool when the driving tool is pulled out after driving the drain material into the ground by the driving machine By detecting the position one after another and comparing the pulling speed of the driving tool with the detection signal, it is possible to know the correct driving depth of the drain material. Since the detected portion provided on the drain material is a mesh piece and is permeable through the mesh, drainage performance is not impaired at the detected portion, and since the mesh piece itself has flexibility, the detected portion has a drain. The flexibility of the material is not impaired. In particular, a drain material in which cutouts communicating with adjacent water passages of the drain material are provided alternately in the length direction with a range in which the notch is provided in the protruding rib and a range in which the cutout is not provided, and the cutout in the range in which the cutout is provided is arranged in a fish shape When the copper-based metal mesh piece is provided, the driving depth and the rise can be detected, and since it is easy to bend regularly at the time of consolidation, water in the ground can be efficiently discharged to the ground surface, and the ground can be uniform. Can be compacted.

[0010]

That is, the gist of the present invention is that a large number of ribs substantially parallel to the longitudinal direction are integrally formed on the front and back surfaces of a flat substrate between two water-permeable materials facing each other. A core material is interposed, the tip of the ridge rib is joined to the permeable material, and a drain material having a number of water passages surrounded by each ridge rib, the permeable material, and the plate-like substrate is used. The first invention is a drain material characterized in that a copper-based metal mesh piece is interposed at regular intervals in the longitudinal direction, and in the first invention, the copper-based metal mesh piece is made of brass, A drain material having a mesh size of 100 to 250 mesh is defined as a second invention. In the first or second invention, a range in which a notch communicating with an adjacent water passage is provided in a ridge rib and a range in which a notch is not provided. And drain material provided alternately in the longitudinal direction of the drain material. The third invention.

The copper-based metal mesh piece has a mesh of 100 to 25.
0 mesh (number of meshes per inch) and thickness of 0.
Those having a thickness of about 0.05 to 0.15 mm are preferable because they have good detectability and have a good balance between water permeability and flexibility. This is because as the mesh size becomes smaller than 100 mesh, the generation of the eddy current becomes too weak to make the detection difficult, and when the mesh size exceeds 250 mesh, it becomes difficult not only to generate the eddy current, but also the water flow function and the flexibility are reduced. It is. As the metal forming the mesh piece, a copper-based metal, particularly brass, is preferably used because generation of an eddy current can be clearly detected when the metal enters the oscillation magnetic field of the detector. In addition, the metal mesh pieces are arranged at regular intervals (for example, every 1 m or every 2 m) in the length direction at the center in the width direction of the drain material.

According to the present invention configured as described above,
Drain material can be driven into the ground as follows. That is, using a dedicated driving machine, driving the drain material into the ground along the driving tool built in the tip with a detecting means that reacts to the copper-based metal mesh piece provided on the drain material, and then driving When the tool is pulled out, the height of each detected part (copper-based metal mesh piece) of the underground drain material is successively detected by a magnetic proximity method by a detecting means provided at the tip of the driving tool, and the driving method is performed. By comparing the pull-out speed of the insertion tool with the detection signal, the correct driving depth of the drain material can be known. At this time, if there is an abnormality in the detection signal, it can be determined that a construction defect such as a rising phenomenon of the drain material or breakage of the drain material has occurred. Therefore, it is possible to take appropriate measures such as re-draining the drain material.
In addition, since the detected part provided on the drain material is a copper-based metal mesh piece, the drainage performance is not impaired at that part, and the mesh piece is flexible, so that the characteristics of the drain material body at the time of consolidation are reduced. Accordingly, it is possible to bend regularly.

[0013] By providing a range in which notches communicating with adjacent water passages in the protruding rib (notch zone) and a range in which no notch is provided (normal zone) are alternately provided in the longitudinal direction of the drain material, a part of the rib is provided. Even if the waterway is clogged, the notch ensures the waterway, and the rigidity of the drain material changes repeatedly at regular intervals in the length direction.
During consolidation in the soil, the drain material is likely to bend regularly in accordance with the rigidity. Furthermore, the arrangement of the notches in the notch zone is made wider in the width direction at the center in the length direction of the notch zone, narrower toward the normal zone, and converges toward the center of the width, so that the length of the drain material is reduced. The rigidity change in the vertical direction becomes continuous, and the curvature of the drain material due to the consolidation becomes more regular.

The pitch P in the length direction of the notch may be the same or different. The position of the notch 25 on the front and back is preferably shifted in the longitudinal direction (arrow L) as shown in FIG. 1 from the viewpoint that buckling hardly occurs in the soil. 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, on the contrary, when the length of the normal zone is longer than 3.0, the curvature in the soil becomes too large, and the dispersion of the drainage distance becomes large. As a result, a delay in consolidation settlement tends to occur. Therefore, the ratio of the length of the normal zone to the notch zone is preferably in the range of 0.5 to 3.0, and more preferably in the range of 1.0 to 2.0.

Notches 25 are not necessarily on the same line (K-
In K), it is not necessary to provide the ribs on all the ribs, and the ribs may be provided so that adjacent water passages communicate with each other at at least one location in the cutout zone. The shape of the notch 25 may be a semicircle or a rectangle, and the width of the notch 25 is preferably approximately equal to the width of the water passage 24. This is because, if the width of the notch is substantially the same as the width of the water passage, no clogging of the notch occurs, and the communication between the adjacent water passages can be ensured and the drainage can be performed more smoothly.

Thus, according to the drain material of the present invention,
It is possible to drive with high reliability, and as shown in FIG. 8 (b), the drain material 30 is regularly curved in the depth direction (arrow D) with respect to the ground surface G, and water in soft ground is removed. The water can be efficiently drained to the ground surface in a short period of time through the water channel to strengthen the consolidation of the ground.

[0017]

Embodiments of the present invention and comparative examples will be described below with reference to the drawings.

(Example 1) FIG. 2 is a view schematically showing a manufacturing process of a drain material of the present invention. In FIG. 2, a belt-like plate made of polyethylene is extruded by an extruder 1 and passed between a pair of embossing rolls 2, 2 provided immediately after.
As shown in FIG. 3, a notch zone (2 in FIG. 3) is formed on a ridge rib (23 in FIG. 1) extending substantially parallel to the length direction on both front and back surfaces.
6) and the normal zone (27 in FIG. 3) are alternately arranged, and the notches (25 in FIG. 1) are widely distributed over the entire width at the center of the notch zone, and become narrower toward the normal zone and have a smaller width. A core material 3 having notches arranged so as to converge at the center was obtained. Next, the core material 3 was passed between polyethylene nonwoven fabrics supplied from nonwoven fabric (water permeable) rolls 4 and 5. Then, a brass mesh piece as shown by reference numeral 6 in FIG. 1 is placed on the lower non-woven fabric fed from the roll 5 by a signal sent from an instrument (not shown) for counting the number of rotations of the length measuring roll 7. It was placed at regular intervals on the nonwoven fabric from a supply device (not shown). Next, the tip of the ridge rib of the core body and the nonwoven fabric are welded by a pair of heat rolls 8 and 8,
Cut to predetermined width by slitter 9 and take-up roll 1
By winding the film by a winder 12 through 0 and 11, FIG.
As shown in FIG.

The obtained drain material has two long polyethylene nonwoven fabrics (water-permeable materials) 21 and 21 'each having a thickness of 0.3 mm and a width (in the WW direction) of about 97 mm, and are separated by about 3.6 mm. A polyethylene core material having ribs 23 formed on both sides of a flat substrate 22 is interposed between the two nonwoven fabrics.
36 water passages 24 surrounded by 1 ′ and the flat substrate 22
(Width 2 mm × height 1.3 mm on the substrate side) is formed vertically above and below the substrate.

FIG. 3 shows the arrangement of the notches in the notch zone. The notch zones 26 and the normal zones 27 are provided alternately in the longitudinal direction.
The arrangement of the notches in the center of the length of the notch zone 26 is wide in the width direction of the drain material and the number thereof is large, and the distribution becomes narrow toward the normal zone 27 and converges to the center in the width direction. doing. (The thick line in FIG. 3 indicates the portion where the notch exists). The length of the notch zone in FIG.
0 mm, the length of the normal zone was 430 mm, and the ratio of the length of the notch zone to the length of the normal zone was 1: 1.79.

A plurality of notches 25 (width 2 mm × depth 0.7 mm) are provided in the protruding ribs 23 formed on both sides of the flat substrate 22 at a pitch of 15 mm in the longitudinal direction (arrow L). I have. Further, the tip of the ridge rib 23 of the core material and the nonwoven fabric 21
Between them, a brass mesh piece 6 (200 mesh) of 40 mm × 40 mm × 0.08 mm thickness is interposed every 1 m in the longitudinal direction at the center in the width direction of the drain material.

(Example 2) A drain material with a mesh piece to be detected was obtained in the same manner as in Example 1 except that a brass mesh piece having a mesh size of 100 mesh was used.

Example 3 A drain material with a mesh piece to be detected was obtained in the same manner as in Example 1 except that the mesh piece made of brass was 250 mesh.

Comparative Example 1 Example 1 was repeated except that a brass mesh piece having a mesh size of 40 mesh was used.
In the same manner as in the above, a drain material with a mesh piece to be detected was obtained.

(Comparative Example 2) A drain material with a mesh piece to be detected was obtained in the same manner as in Example 1 except that the mesh piece made of brass was 300 mesh.

(Comparative Example 3) As a detection piece, 40 mm × 4
A drain member with a piece to be detected was obtained in the same manner as in Example 1 except that a stainless steel plate (without mesh) having a thickness of 0 mm and a thickness of 0.1 mm was used.

(Comparative Example 4) A drain material with a detected mesh piece was obtained in the same manner as in Example 1 except that a mesh piece made of stainless steel and having a mesh size of 200 mesh was used as the detected piece. Was.

(Comparative Example 5) A drain material with a mesh piece to be detected was obtained in the same manner as in Example 1 except that notches were not provided in the protruding ribs of the core material.

As shown in FIG. 9, the detection ability of the drain material with the detection piece obtained as described above is compared with the constant speed moving means 42 for moving the sample (drain material) 41 at a constant speed and 12 mm from the sample 41. The moving speed of the sample 41 is 6 m / min by a detection capability measuring device that holds a detector (proximity switch “APS-15-15N” manufactured by Koyo Electronics Co., Ltd.) 43 at a distance.
The measurement was performed under the conditions of a detection distance L = 12 mm and a transmission frequency = 100 Hz. Table 1 shows the results. In Table 1, the detection ability (millisecond) indicates that the sample 41
3 indicates the time during which the proximity switch 43 senses when the proximity switch 43 is moved in parallel, and X indicates that no sensing was performed.

[0030]

[Table 1]

As is apparent from Table 1, only the brass mesh pieces having a mesh size in a specific range among the brass mesh pieces have the detection ability, and all of the examples 1 to 3 have the detection ability. Have. However, in stainless steel, only the plate has the detecting ability, and the mesh stainless steel has no detecting ability.

Next, based on the results shown in Table 1, using the drain materials of Example 1, Comparative Example 3 and Comparative Example 5 having a detecting ability, a test piece was placed in a consolidation tester as shown in FIG. Installed so that it is at the center in the height direction, and the moisture content is 110-1
Compressed air pressure 0.75kgf / cm
^{2. A} consolidation test was performed under the conditions of a compression ratio of 30%. To explain the consolidation tester of FIG. 10, the height (H) is 35.5.
cm, the inside is a rectangle 9.7 cm wide and 33 cm long (L), 44 is a compressed air port, 45 is a drain port, 46 is a piston, 47 is a sand layer, 48 is a vinyl sheet, 49 is clay,
Reference numeral 50 denotes a drain material (having a thickness of 3.6 mm and a width of 9.7 cm), 51a and 51b detents for the drain material, 52 a displacement gauge, and 53 a strain gauge. Table 2 shows the water content at the symmetrical position 8 cm away from the drain material at the center in the height direction after compaction. FIG. 11 shows a curved state of the drain material of Example 1 after compaction. In Table 2, those having a water content of less than 55% on both sides were evaluated as good (○), and those having at least one side of 55% or more were evaluated as poor (x).

[0033]

[Table 2]

As is clear from Table 2, the drain material of Example 1 has the same water content as the side without the detected piece as well as the side without the detected piece, but Comparative Example 3 has poor water permeability on the side with the detected piece. Comparative Example 5 is considered to have an effect without notches.

Further, as is apparent from FIG.
The drain material was curved to the left and right at substantially the same ratio with respect to the depth direction, and was similar to the drain material without the brass mesh piece.

[0036]

According to the present invention, it is possible to perform a reliable driving by detecting a driving depth and a rise, and to bend regularly in consolidation, thereby discharging water in soft ground to the ground surface in a short time. Thus, a drain material capable of rapidly strengthening the consolidation of the ground can be provided.

[Brief description of the drawings]

1 (a) is a perspective view of the drain material of the present invention with a part cut away, FIG. 1 (b) is a cross-sectional view of the drain material of the present invention, and FIG. 1 (c) is a brass mesh piece; FIG.

FIG. 2 is a view schematically showing a manufacturing process of the drain material of the present invention.

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

FIG. 4 is a perspective view in which a part of a conventional drain material having a corrugated water passage is cut away.

FIG. 5 is a cross-sectional view of another conventional drain material having a corrugated water passage.

FIG. 6 is a partially cutaway perspective view of a conventional drain material having a water channel having a double-sided groove shape.

7 (a) is a cross-sectional view of a conventional drain material having a cut, and FIG. 7 (b) is a cross-sectional view taken along the line BB of FIG. 7 (a).

FIG. 8A is a schematic view showing a state of curvature of a conventional drain material in the depth of the ground, and FIG. 8B 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.

FIG. 9 is a side view of the detection capability measuring device.

FIG. 10 is a side sectional view of a consolidation tester.

FIG. 11 is a diagram showing a state of deformation of a drain material in a depth direction in a consolidation test.

[Explanation of symbols]

 6 ... brass mesh piece 21, 21 '... non-woven fabric 22 ... substrate 23 ... ridge ribs 24, 29, 29', 29 "... water passage 25 ... notch 26 ... notch zone 27 ... normal zone 28, 28 '... Base material 30 ... Drain material 31 ... Groove material 32 ... Cut

Claims (3)

[Claims] 1. A core material comprising a plurality of ridged ribs which are integrally formed on two sides of a flat substrate and are substantially parallel to a longitudinal direction between two permeable members facing each other. In the drain material, which has a large number of water passages surrounded by the ribs, the permeable material, and the flat substrate, the copper-based material is joined at regular intervals in the longitudinal direction between the core material and the permeable material. A drain material comprising a metal mesh piece interposed. 2. The drain material according to claim 1, wherein the mesh piece made of copper-based metal is made of brass, and the mesh size is 100 to 250 mesh. 3. The drain material according to claim 1, wherein a notch communicating with the adjacent water passage is provided in the rib in a range alternately in a longitudinal direction of the drain material.