JP2008025219A - Impervious sheet for embankment method, embankment structure and embankment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impervious sheet for use in an embankment method, which prevents sliding thereof with respect to materials on an embankment, and to provide an embankment structure and an embankment method. <P>SOLUTION: A nonwoven fabric sheet 26 arranged so as to face an embankment area 30 is formed of a nonwoven fabric made of polyester, polypropylene, etc. The coefficient of friction of a front surface of the nonwoven fabric sheet 26 is higher than that of a front surface of the impervious sheet 24. Preferably the coefficient of friction of the front surface of the nonwoven fabric sheet 26 is set to 0.8 or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water-insulating sheet for a banking method, a banking structure, and a banking method, and in particular, a water-blocking sheet for a banking method disposed at the interface between a natural ground and a banking, and the water-blocking sheet for the banking method. The present invention relates to a banking structure and a banking method.

In recent years, lightweight embankment methods are known as embankment methods for soft ground, steep slopes, and the like. In this lightweight embankment method, the embankment portion is formed of a lightweight embankment material having lightness and fluidity. At the interface between the embankment and the natural ground, a structure for preventing drainage and water from entering the embankment is required (see Patent Document 1). Therefore, a water shielding sheet may be arranged at the interface between the embankment and the natural ground. However, the surface of the water-impervious sheet generally has a low coefficient of friction, causing slippage between the water-impervious sheet and the material on the embankment side, and a lighter embankment material increases the downward load along the interface. There was a problem that.
JP 2001-220746 A

  The present invention has been made in consideration of the above facts, and provides a water shielding sheet for a banking method, a banking structure, and a banking method capable of suppressing slippage between materials on the banking side. Is an issue.

  In order to solve the above-mentioned problem, the water-impervious sheet for embankment method according to claim 1 is a water-impervious sheet for embankment method disposed between a natural ground and a lightweight embankment material for the natural ground, A ground protection sheet disposed on the natural ground side, a water shielding sheet adhered on the opposite side to the natural ground of the natural ground protection sheet, and an adhesive on the opposite side of the water shielding sheet to the natural ground protection sheet A non-woven fabric sheet.

  Here, the lightweight embankment material refers to a material having lighter weight than ordinary soil, such as a bubble-mixed lightweight soil used in a lightweight banking method, and generally, a bubble-mixed mortar or the like is used.

  According to the said structure, since the nonwoven fabric sheet is adhere | attached on the water-impervious sheet, when a lightweight embankment material is laid on the outer side of a nonwoven fabric sheet, the fiber of the surface of a nonwoven fabric sheet will enter in a lightweight embankment material. Therefore, when the lightweight embankment material is cured, the fibers of the nonwoven fabric sheet are fixed in the lightweight embedding material in a state where the fibers are intertwined with the lightweight embankment material. Thereby, a banking part and a nonwoven fabric sheet are adhere | attached firmly, and the slip between a banking part and a nonwoven fabric sheet can be suppressed.

  The water-impervious sheet for embankment method according to claim 2 is characterized in that the nonwoven fabric sheet has a larger coefficient of friction than the water-impervious sheet.

  If the nonwoven fabric sheet has a large friction coefficient, slippage can be suppressed even if the nonwoven fabric sheet loses the adhesiveness as described above with the lightweight embankment material.

  The water-impervious sheet for embankment method according to claim 3 is characterized in that the ground-mountain side protection sheet includes a nonwoven fabric.

  Thus, drainage properties, such as groundwater from a natural ground, can be improved by using a nonwoven fabric as a natural ground side protection sheet.

  The water-impervious sheet for embankment method according to claim 4 is characterized in that the non-woven fabric sheet is thinner than the natural ground side protective sheet.

  Since a nonwoven fabric sheet is a layer provided for adhesion | attachment with a banking part, thickness may be thinner than the natural mountain side protection sheet provided for drainage improvement. Since the water-impervious sheet for the embankment method preferably has a thinner overall thickness in consideration of ease of construction, the overall thickness can be reduced by reducing the thickness of the nonwoven fabric sheet.

  The embankment structure according to claim 5 is a embankment structure embankment using a light embankment material with respect to a natural ground, and a natural ground side protection sheet disposed so as to cover the natural ground, and the natural ground side protection A water shielding sheet adhered to the opposite side of the ground of the sheet, a non-woven sheet adhered to the opposite side of the ground protecting sheet of the water shielding sheet, and a side of the nonwoven sheet opposite to the water shielding sheet. And an embankment portion formed using the lightweight embankment material.

  According to the said structure, since the nonwoven fabric sheet is arrange | positioned between the water-impervious sheet and the embankment part, the slip of an embankment part can be suppressed.

  The embankment method according to claim 6 is a embankment method in which a light embankment material is used for embankment, and the water shielding sheet for embankment method according to any one of claims 1 to 4. Then, using the lightweight embankment material on the outside of the non-woven fabric sheet of the water shielding sheet for the embankment method and the sheet disposing step, which covers the natural mountain by disposing the natural ground side protection sheet side on the natural ground side. And a bank part forming step for forming the bank part.

  According to the above-mentioned embankment method, since the nonwoven fabric sheet is bonded to the embankment side of the water-impervious sheet for the embankment method, the embankment portion can be easily formed and slippage of the embankment portion can be suppressed.

  Since this invention set it as the said structure, the slip between materials on the embankment side can be suppressed.

  The embankment structure 10 according to the present invention is a structure used when embankment is performed on a steep slope or soft ground.

  As shown in FIG. 1, a natural slope 12 has a steeply inclined slope 14. The surface of the slope 14 is covered with a water shielding sheet 20 for the embankment method. As shown in FIG. 2, the embankment method water-impervious sheet 20 is configured by laminating a ground-mountain-side protection sheet 22, a water-impervious sheet 24, and a nonwoven fabric sheet 26 in this order from the ground-mountain 12 side. .

  The natural mountain side protection sheet 22 can be comprised with the nonwoven fabric which uses polyester, a polypropylene, etc. as a material. The thickness D1 of the natural mountain side protection sheet 22 is preferably in the range of 2 mm to 15 mm. This is because the natural mountain side protection sheet 22 is disposed on the natural mountain 12 side and becomes a water-permeable layer of water that infiltrates from the natural mountain 12 such as groundwater, so that it is 2 mm or more from the viewpoint of ensuring drainage. This is because the necessary drainage performance can be secured at about 15 mm.

  The water-impervious sheet 24 is constituted by a sheet having a water-impervious property and can be made of an ethylene vinyl acetate copolymer, polyvinyl chloride, or the like. Moreover, it is preferable that the water shielding sheet 24 has a thickness of 0.8 mm to 1.5 mm.

  The nonwoven fabric sheet 26 can be comprised with the nonwoven fabric which uses polyester, a polypropylene, etc. as a material. It is preferable that the friction coefficient of the surface of the nonwoven fabric sheet 26 is 0.8 or more.

  In addition, it is preferable that thickness D2 of the nonwoven fabric sheet 26 is thinner than thickness D1 of the natural ground side protection sheet 22. FIG. This is because the non-woven fabric sheet 26 is provided in order to increase the adhesive force with the embedding portion 30 described later, and does not need to have a drainage function like the natural mountain side protection sheet 22. This is because, by reducing the thickness, the entire thickness of the water shielding sheet 20 for the embankment method is reduced. Specifically, the thickness D2 can be set to 0.3 mm to 0.6 mm.

  The natural mountain side protection sheet 22, the water shielding sheet 24, and the nonwoven fabric sheet 26 are bonded or wholly bonded to each other. The bonding may be any method as long as it does not perforate the water shielding sheet 24. For example, the bonding is performed by bonding using an adhesive, direct heating and melting between sheets, or heating and melting using a melting member. be able to.

  As FIG. 1 shows, the embankment part 30 is comprised in the outer side of the water shielding sheet 20 for embankment methods. As a material constituting the embankment 30, a lightweight embedding material such as a bubble mixed mortar or a bubble mixed concrete can be used. A retaining wall 16 is formed on the opposite side of the embankment 30 from the natural ground 12, and the embankment 30 is formed between the retaining wall 16 and the natural ground 12. The upper surface of the embankment portion 30 is covered with the upper surface water shielding sheet 18.

  A drainage groove 19 is provided below the water-impervious sheet 20 for the embankment method near the retaining wall 16. The groundwater flows downward through the natural mountain side protection sheet 22, reaches the drainage groove 19, and is drained to a predetermined place by the drainage groove 19.

  Next, the construction method of the above-mentioned embankment structure 10 is demonstrated.

  First, the retaining wall 16 is formed on the slope 14 where embankment is performed, and the drainage groove 19 is installed in the vicinity of the retaining wall 16. Next, the slope 14 is covered with the water-impervious sheet 20 for the embankment method. The water shielding sheet 20 for the embankment method is installed so that the natural mountain side protection sheet 22 is arranged on the slope 14 side.

  Then, a lightweight embankment material is placed between the impermeable sheet 20 for embankment construction and the retaining wall 16. The placed lightweight embankment material enters the fibers of the nonwoven fabric sheet 26. After placing, curing for a predetermined time to cure the lightweight embankment material. Thereby, the fiber of a nonwoven fabric sheet is fixed in a lightweight embankment material in the state intertwined with the lightweight embankment material. Then, the embankment part 30 is formed and the upper surface of the embankment part 30 is covered with the upper surface water-impervious sheet 18.

  According to the water-impervious sheet 20 for the embankment method of the present embodiment, since the nonwoven fabric sheet 26 is provided on the embankment portion 30 side, the fibers of the nonwoven fabric sheet 26 are intertwined with the lightweight embankment material, and the embankment portion 30 and the nonwoven fabric. The sheet 26 can be firmly bonded. Moreover, since the friction coefficient of the nonwoven fabric sheet 26 is larger than that of the water-impervious sheet 24, the friction with the embankment portion 30 can be increased, and even when the nonwoven fabric sheet 26 is peeled off from the lightweight embankment material, the embankment portion 30. The downward load along the slope 14 can be reduced.

  In the present embodiment, an example in which nothing is arranged in the embankment 30 has been described. However, as shown in FIG. 3, a wire mesh 32 may be arranged in the horizontal direction. The embankment 30 can be reinforced by arranging the wire mesh 32.

  [Example 1]

  Next, the Example which confirms the adhesiveness between the nonwoven fabric sheet 26 of this embodiment and a lightweight embankment material is demonstrated.

  Three types of specimens A to C were prepared by adhering a lightweight embankment material to the surface of a sheet obtained by laminating a nonwoven fabric on the surface of the water shielding sheet (hereinafter referred to as “waterproof sheet with nonwoven fabric”). Specimens A to C were classified into the following three types depending on the location of preparation and blending.

  The specimen A was created at the construction site. After preparation of the specimen A, the specimen A was moved by the vehicle at the early stage of the material age and continuously vibrated, so that material separation occurred, and the contact portion with the nonwoven fabric was mainly cement milk.

  Specimens B and C are specimens prepared in the test room, and the unit volume weights of the materials are different. Table 1 shows the measured unit volume weight.

供試体Ａ〜Ｃは、次の手順で作成した。

Specimens A to C were created by the following procedure.

1. A plastic container having an inner size of about 25 × 12 × 7 cm was used as a simple mold, a water-impervious sheet with a nonwoven fabric was attached, and an exposed portion of the water-impervious sheet was provided in part.

2. The container was filled with a lightweight embankment material.

3. After curing, the mold was removed, and the adhering portion with the water-impervious sheet with a nonwoven fabric was cut out to about 5 × 5 × 2 cm to obtain a test piece. The test pieces were 8 specimens A to C, respectively.

  Next, the adhesion strength test was done about the test piece of each specimen AC.

  Since the load acting on the adhesion portion is a load on which the lightweight embankment material tries to slide on the waterproof sheet with nonwoven fabric, the adhesion strength is evaluated by the strength in the tensile shear direction.

  In the test, the test piece was attached to the fixture of a tensile tester and the test speed was 50 mm / min. The maximum load until the break (peeling) was read and used as the test value.

Since the adhesion area of the waterproof sheet with nonwoven fabric and the lightweight embankment material varies depending on the conditions at the time of demolding and cutting out the test piece, the adhesion area of each test piece is measured in advance, and the test value obtained above is attached to this adhesion value. Dividing by area gave the adhesion strength (N / cm ² ).

  Tables 2 to 4 show the adhesion strength test results of the specimens A to C.

表２は、サンプルＡの付着強度試験結果であり、材齢（日）が３０日、モルタルミルク状（材料分離）という条件である。

Table 2 shows the results of the adhesion strength test of Sample A, in which the age (day) is 30 days and the condition is mortar milk (material separation).

表３は、サンプルＢの付着強度試験結果であり、材齢（日）が２２日、圧縮強度 ８ｋＮ／ｍ^３という条件である。

Table 3 shows the adhesion strength test results of Sample B, in which the age (day) is 22 days and the compressive strength is 8 kN / m ³ .

表４は、サンプルＣの付着強度試験結果であり、材齢（日）が２２日、圧縮強度 １０ｋＮ／ｍ^３という条件である。

Table 4 shows the adhesion strength test results of Sample C. The material age (day) is 22 days and the compressive strength is 10 kN / m ³ .

  <Discussion>

(1) For any of the three types of specimens A to C, it was confirmed that adhesion was obtained between the nonwoven fabric and the water shielding sheet.

(2) When the waterproof sheet with nonwoven fabric was forcibly removed from the lightweight embankment material, entanglement of the nonwoven fabric fibers and the lightweight embankment material could be observed.

(3) About the exposed part of the water shielding sheet, the lightweight embankment material was easily peeled off. From this, it can be understood that the nonwoven fabric contributes to the attachment of the lightweight embankment material.

(4) About the difference in the adhesion strength due to the difference in the lightweight embankment material, etc., a large adhesion force was obtained in the order of specimen A> sample B> sample C.

(5) It is considered that the specimen A is a material mainly composed of cement milk due to material separation and has a small amount of bubbles, and because the contact area between the nonwoven fabric and the mortar is large, the adhesion strength is also increased.

(6) Specimens B and C are considered to have little difference in measured values of unit volume weight and no difference in bubble volume. Regarding the fact that the specimen B showed a greater adhesive force, it is considered that other blending and placing conditions are factors.

(7) From the above, it was confirmed that when a light-weight embedding material was placed on the surface of the water-impervious sheet with a non-woven fabric, the fibers of the non-woven fabric were entangled with the light-weight embedding material and adhesion was obtained after curing.

  [Example 2]

  The friction characteristic test was implemented about the water-impervious sheet (Example sheet) for the embankment method according to the present invention, and the A sheet and B sheet as comparative examples. As shown to FIG. 4 (A), as for the A sheet | seat, the surface by the side of a embankment part is comprised with the water-impervious sheet | seat. Moreover, as shown to FIG. 4 (B), as for the B sheet, the rib R is comprised on the surface of the water-impervious sheet facing the embankment part side. The B sheet has a characteristic that the friction coefficient is larger than that of the flat surface water shielding sheet, but the thickness is thick and the workability is poor. The friction coefficient μ of each sheet is 0.87 for the example sheet, 0.47 for the A sheet, and 0.72 for the B sheet.

  The test sheet on which the bubble mixed mortar is cured is placed on the surface of each of the example sheet and the A sheet and the B sheet as a comparative example, and the inclination angle at which the test piece starts to slide is gradually increased by gradually increasing the inclination angle of each sheet. It was measured. The measurement results are shown in [Table 5].

表５から、実施例シートは、ＦＣＢ工法用のシートとして日本道路公団の示す「摩擦係数０．５以上」に合致しているといえる。また、傾斜角４１°以上でも滑り出さず、盛土部に対して高い保持機能を有している。

From Table 5, it can be said that the example sheet matches the “friction coefficient of 0.5 or more” shown by the Japan Highway Public Corporation as a sheet for the FCB method. Moreover, it does not slide out even at an inclination angle of 41 ° or more, and has a high holding function with respect to the embankment portion.

It is sectional drawing which shows the embankment structure of this embodiment. It is a cross-sectional view of the impermeable sheet for the embankment method of the present embodiment. It is sectional drawing which shows the modification of the embankment structure of this embodiment. It is sectional drawing of the sheet | seat of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filling structure 12 Ground mountain 14 Slope 20 Water-impervious sheet 22 for embankment method Ground-mountain side protection sheet 24 Water-impervious sheet 26 Non-woven sheet 30 Embankment

Claims (6)

A water-impervious sheet for the embankment method disposed between a natural ground and a lightweight embankment material for the natural ground,
A natural ground side protection sheet disposed on the natural ground side;
A water shielding sheet bonded to the opposite side of the natural mountain side protective sheet, and
A non-woven sheet adhered to the reverse side of the ground protection sheet of the water shielding sheet;
Water shielding sheet for embankment method with   The said nonwoven fabric sheet has a larger coefficient of friction than the said water shielding sheet, The water shielding sheet for embankment methods of Claim 1 characterized by the above-mentioned.   The water shielding sheet for embankment method according to claim 1 or 2, wherein the ground mountain side protective sheet is configured to include a nonwoven fabric.   The said nonwoven fabric sheet is thinner than the said natural ground side protection sheet, The water-impervious sheet for embankment methods of any one of the Claims 1 thru | or 3 characterized by the above-mentioned. It is a banking structure that fills the ground with a lightweight banking material,
A natural ground side protection sheet disposed so as to cover the natural ground,
A water shielding sheet bonded to the opposite side of the natural mountain side protective sheet, and
A non-woven sheet adhered to the reverse side of the ground protection sheet of the water shielding sheet;
On the opposite side of the nonwoven fabric sheet to the water-impervious sheet, a bank part formed using the lightweight bank material,
Embankment structure with. It is an embankment method for embankment using a lightweight embankment material against natural ground,
A sheet disposing step for covering the natural mountain by disposing the natural mountain side protection sheet side on the natural mountain side with the water shielding sheet for embankment method according to any one of claims 1 to 4.
Forming the embankment part using the lightweight embankment material on the outside of the nonwoven fabric sheet of the water-impervious sheet for the embankment method, an embankment part forming step,
On the outside of the embankment-side protective layer, a embankment portion is formed using a lightweight embankment material,
Filling method including

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