JPH05106217A - Civil engineering drain material - Google Patents

Abstract

PURPOSE:To correct deflection to be applied to filtering material, and protect the filtering material by bonding core material and the filtering material to each other with rubber-state elastic bonding material, and by composing the bonded section of both the materials slidably according to a tensile force to be applied to, after both the materials are embedded in ground. CONSTITUTION:Band-shaped sheet rugged-mold core material 4 having a plurality of independent projections formed with hard polyvinyl chloride or the like excellent in water resistance, is covered with water-permeable filtering material 3 formed with the thermally pressure-fitting type non-woven fabric of polyester fibers or the like. After that, a partial section at least among sections for the core material 4 and the filtering material 3 in contact with each other is bonded with bonding material 2 displaying rubber-state elasticity at a room temperature with, SBS or SIS as the main body and they are integrally formed, and a drain 1 is composed. Till manufacturing, carrying, storing, and embedding in ground, for the drain material 1 are completed, the core material 4 and the filtering material 3 are properly bonded to each other, and when mutual tensile forces are worked on the bonded section of both the materials 3, 4 after they are embedded in ground, then according to the tensile forces, the bonded section can be extened to be slidably moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial drain material for civil engineering. More specifically, the present invention mainly relates to an artificial vertical drain material suitable for deep ground improvement.

[0002]

2. Description of the Related Art In recent years, land reclamation of oceans and lakes has been actively carried out for the redevelopment of the national land. The sand pile method has been mainly used as a drainage consolidation method mainly using natural water-permeable materials such as sea sand, but the development of artificial drain materials is required against the backdrop of depletion of sea sand and rising prices. .. However, it is not uncommon for the vertical settlement material for large depths, which mainly targets the soil with a high water content, to have a consolidation settlement rate of more than 50%, and the drain material undergoes compression and bending deformation of 50% or more in the soil. Is not uncommon.

By the way, as an artificial vertical drain material,
Many proposals have been made so far in which the peripheral surface of a plastic core material is coated with a water-permeable material. There are roughly two types of structures for composite integration of a core material and a water-permeable material in the artificial drain materials proposed so far. One is that, as described in Japanese Patent Publication No. 22168/1990, the core material is simply covered with a water-permeable material, and the core material and the water-permeable material can freely slide on each other. The other one is a core material and a water-permeable material as described in JP-A-63-67321, JP-A-1-207515, etc., which have high durability over a part or the entire surface. This type is rigidly fixed by a hard adhesive.

However, the two types described above have the following problems, respectively. Therefore, they are not in full use as the vertical drain material for large depth. Usually, these strip-shaped drain materials are manufactured as a long product in the form of a roll, but in the former non-adhesive type drain material, the strip material is not integrated because the core material and the water-permeable filter material are not integrated. When the long product of is rolled up, the core material and the filtering material show different behaviors, and there is a defect that the coated filtering material is partially dubbed or wrinkles, which is caused in the soil. When earth pressure is applied to the drain material, the coated filter material in the relevant portion may be easily deformed by the action of the earth pressure to cause a problem such as reducing the water passage cross-sectional area of the drain material. Further, in this type, there is a problem that the work is incomplete due to the sliding between the core material and the filter material in the work of gripping the tip portion with the mandrel and placing it in the soil.

Further, the latter durable and rigid adhesion type drain material has no problems in manufacturing the drain material, and has an advantage that it is excellent in handling performance and initial performance until the end of pouring in the soil, but for large depths. When used as a vertical drain material, of course, a high level of consolidation settlement phenomenon occurs in the ground, and accordingly, a high level of axial compression is applied to the drain material, which causes the drain material to largely bend. Since the core material and the filter material are firmly bonded to each other partially or entirely by a durable hard adhesive, the filter material that has been subjected to a high tensile action is broken or punctured on the outer peripheral surface side of the curved portion as shown in FIG. There is a problem that it causes a perforation phenomenon and the filter does not function as a filter.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art and to cause the core material and the filter material to slide when placed in the soil, or to break the filter material due to bending. The purpose is to provide civil engineering drainage materials.

[0007]

Therefore, in view of the above-mentioned circumstances, the present inventors have considered that the normal condition, that is, the manufacture of the drain material,
The core material and the filter material are properly combined and integrated until the end of transportation, storage, and placement in the soil.After that, after being buried in the soil, the core material is bent due to the bending phenomenon of the drain material that accompanies consolidation settlement of the ground. When mutual tensile force acts on the joint between the filter material and the filter material,
As a result of earnest efforts to develop an ideal drain material capable of protecting the filter material by absorbing the strain applied to the filter material by the joint portion extending and sliding according to the tensile force, an adhesive material exhibiting rubber-like elastic behavior. The present invention has been made based on the idea.

That is, according to the present invention, the periphery of a strip-shaped plate-shaped core material having a large number of independent projections is covered with a water-permeable filter material, and the water-permeable filter material and the core material are in contact with each other. Is a drain material for civil engineering, characterized in that at least a part thereof is bonded by an adhesive material that exhibits rubber-like elasticity at room temperature. The strip-shaped plate-shaped core material used in the present invention is not particularly limited as long as it is approximately flat and elongated. As the material, hard polyvinyl chloride, high-density polyethylene, polystyrene, polypropylene, polyvinylidene chloride, polyamide, polyester, etc., which are excellent in water resistance and hard and can be thermoformed, are used. The material thickness of the core material is generally 0 in view of the high ground pressure of deep ground.
It is necessary to secure a large drainage conduit (drainage cross-sectional area) from the viewpoint of the high water content ratio of the deep ground, and the molding thickness of the core material is preferably 4 to 0.8 mm, more preferably 0.6 to 0.7 mm. The thickness is 4 to 8 mm, preferably 6 to 7 mm.

The core material used in the present invention has a large number of independent protrusions. An example of the shape of the independent protrusions is shown in FIGS. 3 and 4. Needless to say, the shape of the independent protrusion is not limited to these. The apex portion of the independent protrusion may or may not be perforated. The center-to-center distance of the independent protrusions is preferably about 10 to 20 mm, but it is desirable to comprehensively determine it in consideration of the material thickness of the core material, the molding thickness and the like. Further, the width of the strip-shaped core material is generally around 10 cm, and the length thereof is preferably about 100 to 200 m, which can be rolled up.

The water-permeable filter material used in the present invention is preferably thermocompression-bonded non-woven fabric such as polyester, polyamide, polypropylene and polyethylene fibers from the viewpoint of water permeability, but polyester is particularly preferable from the viewpoint of water resistance and deformation resistance. preferable. From the viewpoint of soil particle separation performance and earth pressure durability,
The monofilament denier of the constituent fibers is generally 1 to 5 d, more preferably 2 to 4 d, but the basis weight is generally 50 to 200 g /
m more preferably ² well to a 80 to 120 / m ² or so, the degree of dispersion of the fiber array is higher, vertically and horizontally, and two oblique directions substantially, preferably more are evenly distributed array.

In the present invention, an adhesive material which exhibits rubber-like elasticity at room temperature means that it has an appropriate adhesive state under a standard condition (normal temperature) where no tensile load (shearing / peeling) is applied, and the tensile force is applied to the adhesive portion. Refers to an adhesive material having the property that the adhesive film stretches and spreads depending on the magnitude of the tensile force, for example, styrene-butadiene-styrene (SBS), styrene-isobutylene-styrene (S
IS) and other styrene block copolymers, polyester and polyurethane elastomers, and synthetic rubber polymers such as chloroprene rubber, nitrile rubber, and butyl rubber, tackifiers such as rosin, and softeners such as process oil. There may be mentioned an adhesive or the like to which other additives are added according to the above, but it is not necessarily limited to these.

Although these adhesives have hot-melt properties, the most suitable adhesive may be selected in view of the target level of initial adhesive strength. Since the adhesive material used in the present invention is melted and adhered at a high temperature and then cooled and solidified (including natural cooling), it is not re-adhered (adhered) to the non-adhesive part, and It does not unnecessarily reduce the water permeability.

[0013] Here, a proper state of connection means that the drain material is sufficiently durable against various handlings and loads (shearing / peeling) applied until the end of manufacturing, transportation, storage, and placement in the soil, and it is buried in the soil. It refers to a bonded state in which the load strain applied to the core material and the filter material by absorbing and stretching the adhesive against a large shear load applied later can be absorbed and relaxed. In the drain material of the present invention, at least a part of the portion in which the core material and the filter material are in contact with each other is, in terms of cross section, as shown in FIGS. (FIG. 5), whole surface on one side (FIG. 6), both ends of front and back (FIG. 7), both ends on one side (FIG. 8), both ends (FIG. 9), etc.
As shown in FIGS. 12 and 13 in the side view, the entire surface or a part thereof, or a combination thereof, and the bonding pattern of the bonding portion of the projection portion, as shown in FIGS. It refers to the entire surface of the top part, a part thereof, or a combination thereof. These bonded portions and their bonding may be selected appropriately as long as they can withstand various loads and handling until the completion of the driving of the drain material.

To apply the adhesive material to the surface of the core material, a gravure coater, a roll coater, a hot melt spray gun, a hot melt gun or the like may be used. Next, an example of the method for producing a drainage material of the present invention and its effects will be described with reference to FIGS. 25 and 26. FIG. 25 is an explanation showing an example of the method for manufacturing the drain material of the present invention. The plate-shaped core material 4 is continuously fed by a pinch roll 6, and a hot melt adhesive 7 having rubber-like elasticity is applied by a roll coater 8 to the apexes of the protrusions on both front and back surfaces of the core material. Next, the water-permeable filter medium 3 is continuously supplied to the surface of the core material from the roll 3A of the water-permeable filter medium wound separately by the filter medium coating device 9.
The water-permeable filter medium 3 is flow-velocity-coated so as to surround the peripheral surface of the core material, and then the polymerized portion of the filter medium coated with the adhesive (non-aqueous system) extruded by the adhesive extruding device 10 is applied. The drainage material 1 which is fixed, is sent to the drying device 12 by the press roll 11, is supplied, and is rolled up to obtain a long-sized drainage material 1.

FIG. 26 is an explanatory view showing the usage state of the drainage material of the present invention. FIG. 26A shows a state during driving, and FIG. 26B shows a state during consolidation settlement. Note that 13 is the embankment and 14 is the ground surface. The drainage material 1 is supplied to the driving machine, and is drawn vertically into the soil with the tip of the mandrel of the driving machine being held in the soil. According to the present invention, since the core material and the filter medium are firmly integrated by the adhesive material until the production, transportation, and placement of the drainage material are completed, the filter medium is misaligned or damaged, and the handleability is poor. The problem of does not occur at all, and rational manufacturing, transportation, and placement are possible.

The drain material 1 buried in the soil is transferred to the filter material even if the drain material undergoes a large bending deformation of more than 50% as the soil subsidence proceeds. A stable structure can be obtained by sliding an arbitrary distance from the connection point with the core material according to the magnitude of the applied tensile force. As a result, it is possible to endure underground burial for a long period of time without being damaged and to maintain a high drainage function.

Next, the effects of the present invention will be specifically described with reference to examples.

[0018]

[Examples] Performance evaluation was carried out on the following two items in the following manner. 1. Initial adhesive strength (shear adhesive strength / peeling adhesive strength) between the core material and the filter material, as shown in FIG. 22, the vertex diameter d of the convex portion is 5 mmφ,
A strip-shaped provision in which the apex parts of the row of three independent concave-convex molded core materials 4 made of hard polyvinyl chloride having a distance L between the convex parts of the convex portion and the polyester spunbond 15 are joined together with an adhesive. In the standard state (dry state) of the sample, the shear adhesive force and the peel adhesive force were measured and evaluated by the methods shown in FIGS. 23 and 24. The test speed is shear adhesive strength of 1
mm / min, peeling adhesive force 5 mm / min. 2. Durability of the drain material after 1 day of immersion in water The bending performance of the above-mentioned independent concavo-convex molded core material is covered with a polyester spun bond, and all of the apex parts of the convex parts where these materials are in contact with each other are bonded with an adhesive material. The drain material sample with a width of 10 cm and a length of 20 cm is placed in water at 20 ° C. for 24 hours.
After immersing for a period of time, take out and perform compression and bending within 1 minute at a speed of 1 mm / min under a side pressure of 5 kg · f / cm ² ,
The relationship between the compressive deformation rate and the press-bend followability of the spunbond at that time was observed and evaluated.

The polyester spunbond used as the filtering material in this test is a thermocompression-bonding type non-woven fabric having a single yarn denier of 2d, a basis weight of 50 g / m ² and a thickness of 0.18 mm. As is clear from Table 1, the elastomer hot-melt adhesives of Examples 1 and 2 have a sufficient initial adhesive strength for practical use as a whole, although there are some differences depending on the type, and also after immersion in water. It was confirmed that it has a high level of compression-bending followability.

On the other hand, in the case of the curable durable adhesives of Comparative Examples 1 and 2, although the initial adhesive strength is sufficient, the water resistance durability of the adhesives adversely affects the high-level compression-bending followability remarkably. I understand. This result shows that the drain material of the present invention has an ideal function as a deep depth vertical drain material.

[0021]

[Table 1]

[0022]

EFFECTS OF THE INVENTION Since the drain material of the present invention integrates the core body and the filter material with an adhesive material that exhibits rubber-like elasticity at room temperature, a proper bonded state can be obtained in the standard state, After burying, the joint between the core material and the filter material can slide freely according to the magnitude of the tensile force applied between both materials, so a high level compression and bending force acts on the drain material. It is extremely suitable as a vertical drain material for large depths.

Since the drainage material for civil engineering of the present invention has the above-described characteristics, it is highly useful as a vertical drain material for medium / low depth and a horizontal drain material in addition to the vertical drain material for large depth. Yes, it greatly contributes to various ground improvement.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an integrated state of a core material of a drain material and a filtration material of the present invention.

FIG. 2 is a schematic diagram showing a curved state of a drain member.

[Figure 3]

FIG. 4 is a perspective view showing an example of a molded shape of an independent protrusion.

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

FIG. 9 is a sectional state view showing an example of the mutual relationship of integration of the core material and the filter material.

[Figure 10]

FIG. 11 is a schematic plan view showing an example of an adhesive application pattern on a core material surface.

[Fig. 12]

FIG. 13 is a schematic side view showing an example of an adhesive application pattern on the core material surface.

FIG. 14

FIG. 15

FIG. 16

FIG. 17

FIG. 18

FIG. 19

FIG. 20

FIG. 21 is a schematic view showing an example of a pattern of applying an adhesive to the vertexes of the core material projections.

FIG. 22 is a schematic view showing the dimensional relationship of the independent protrusions in the example of the present invention.

FIG. 23 is a schematic diagram of a shear adhesive strength evaluation method.

FIG. 24 is a schematic diagram of a peel adhesion evaluation method.

FIG. 25 is a schematic view showing an example of a method of manufacturing a drain material.

[Fig. 26] Fig. 26 is a schematic diagram showing a state in which the drain material of the present invention is buried in soil, where A is at the time of placing and B is at the time of consolidation and settlement.

[Explanation of symbols]

 1 Drain Material 2 Rubber-like Elastic Adhesive Material 3 Water-permeable Filter Material 4 Concavo-convex Molded Core Material 5 Convex Top 6 Guide Roll 7 Hot Melt Adhesive Liquid Showing Rubber Elasticity 8 Roll Coater 9 Filter Material Covering Device 10 Adhesive Extruding Device 11 Press roll 12 Cooling device 13 Embankment 14 Ground surface d Convex portion apex diameter L Convex portion center distance

Claims (1)

[Claims] 1. A strip-shaped plate-shaped core material having a large number of independent protrusions is coated with a water-permeable filter material on the peripheral surface thereof, and at least one of the portions where the water-permeable filter material and the core material are in contact with each other. A civil engineering drain material, characterized in that the parts are joined by an adhesive material that exhibits rubber-like elasticity at room temperature.