JP5300015B2 - Cover structure of the surface of the levee body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating structure of a dam body surface layer section which has superior water intercepting properties, can secure the required stability of a dam body without increasing the area of site, has earthquake resistance due to superior mechanical characteristics, and has superior construction efficiency. <P>SOLUTION: A high performance fiber-reinforced cementitious composite (HPFRCC) 8 is brought into surface contact with and joined to a water permeable material 5 as a porous concrete which is disposed under the composite and has a coefficient of permeability larger than 10<SP>-2</SP>to form into a laminated structure. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  TECHNICAL FIELD The present invention relates to a covering structure for a surface of a levee body, which is used to renovate a surface layer and improve seismic resistance in a dike for water storage or a river revetment or other dam body installed in an existing agricultural pond. .

  Regarding the renovation of the levee body with the aim of improving earthquake resistance, it may be possible to improve stability by expanding the section of the dam body by relaxing the slope of the levee body slope, but this is costly, The construction period is long, and there is a growing overgrowth of weed trees.

  In addition, in the repair of a bank body covered with alpha-ltd facing, the durability is inferior, the workability is poor, and there is a concern that the surface protection will be cracked after construction.

On the other hand, use of a water shielding sheet such as a waterproof civil engineering sheet is shown in the following patent documents.
Japanese Utility Model Publication No. 50-45885 JP 2001-98526 A JP 2006-322302 A

  These are based on the idea that the levee soil is protected from erosion even if the overflow continues for several hours by laying the sheet. For example, in Patent Document 2, as shown in FIG. Nine cores 18 are embanked, and the cores 18 are further crushed, and the semi-permeable civil engineering sheet 1 of the present invention is continuously applied thereon to cover the cores 18 without gaps.

The semi-permeable civil engineering sheet 1 includes a high-density flat cloth 3 in which 800 to 1200 denier monofilament yarns are woven into 12 to 16 yarns / inch between two synthetic fiber cotton layers 2a and 2b, and polyethylene or ethylene. -Needle punch with a needle density of 45 ± 10 / cm ² from the surface of one side of a two-layer synthetic fiber felt mat with a vinyl acetate copolymer waterproof sheet 4 interposed Processed.

  Furthermore, the customer soil 23 is embanked on the semi-permeable civil engineering sheet 1 and rolled. Finally, concrete 10 is placed on the outside of the bank, the top end 11 is paved as appropriate, and vegetation is constructed on the back slope 12 to complete. It should be noted that the thickness of the customer soil is appropriately several tens of centimeters.

  Reference numeral 13 is river water, 14 is a river bed, 15 is a steel sheet pile, and 16 is a steel ridge.

  Rainwater that has fallen on the surface of the levee penetrates the customer soil 23, penetrates the semipermeable civil engineering sheet 1, and penetrates to the core soil 18. The same applies to air.

  Moreover, since the semi-permeable civil engineering sheet 1 has the synthetic fiber cotton layers 2a and 2b having a large friction coefficient on both sides of the sheet, the customer soil 23 is strongly attached to the synthetic fiber cotton layer 2a, and the core soil 18 is the synthetic fiber cotton. By strongly adhering to the layer 2b and, as a result, through the semi-permeable civil engineering sheet 1, the customer soil 23 and the core soil 18 are strongly bonded.

  In the case of using the water shielding sheet as in Patent Documents 1 to 3, durability is inferior and workability is poor. After construction, there is concern about the outflow of backside soil due to sheet damage.

  In addition, there is a concern that the upstream slope will be eroded after construction because there is an overgrowth of weed trees when embankment is made on the sheet.

  The object of the present invention is to eliminate the inconveniences of the conventional examples described above, to have good water shielding, and to ensure the required levee body stability without expanding the site, and to achieve high earthquake resistance with excellent mechanical properties. The object is to provide a covering structure for the surface layer portion of the levee body having excellent workability.

  In order to achieve the above object, the present invention according to claim 1 is a porous concrete having a water permeability coefficient larger than 10 (−2), in which a plurality of fine cracked fiber reinforced cement composite materials (HPFRCC) are disposed below. The gist is that a laminated structure is formed by surface contact with the water-permeable material and bonding.

  According to the first aspect of the present invention, the multiple fine crack type fiber reinforced cement composite material (HPFRCC) covering the surface of the bank body exhibits high durability and wear resistance.

  Also, when the slope of the levee body is directly coated with multiple fine cracked fiber reinforced cement composite material (HPFRCC), as shown in Fig. 2, there is a water head difference between the pond and the dam body when the water level in the pond is lowered. When the water pressure is applied from the inside of the dam body toward the back surface of the surface impermeable wall, a plurality of fine cracked fiber reinforced cement composite materials (HPFRCC) may be lifted or possibly collapsed or damaged.

  On the other hand, the present invention provides a drainage layer on the back surface (base layer) of the multi-fine crack type fiber reinforced cement composite material (HPFRCC), and the drainage is improved, so that water pressure is not applied. There is no possibility that the cement composite material (HPFRCC) will be lifted, or in some cases, collapsed or damaged.

  The gist of the present invention described in claim 2 is that the bank body is for storing water and is a bank bank for agricultural use.

  According to the second aspect of the present invention, when the water level in the pond decreases, the water head difference between the pond and the embankment is due to the use of stored water as irrigation water during the irrigation period, ) And water reservoirs with low water levels are frequently generated in agricultural ponds, and the presence of a drainage layer is particularly effective for agricultural ponds.

According to the third aspect of the present invention, in the cement composite material, 1 vol. Of PVA (Poly Vinyl Alcohol) short fiber satisfying the following [F1] is added to a cement preparation matrix satisfying the following [M1]. % Or more 3 vol. The gist of the present invention is that it is a crack-dispersed fiber-reinforced cement composite material blended in a blending amount of not more than%.
[M1]
Weight percentage of water binder (W / C): 25% or more Weight ratio of fine aggregate to binder (S / C): 1.5 or less (including 0)
Unit water quantity: 250-450 kg / m ³
Air volume immediately after kneading: 3.5-20%
High-performance AE water reducing agent: less than 30 kg / m ³ [F1]
Fiber diameter: 0.05 mm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500-2400 MPa

  According to the third aspect of the present invention, there is provided an appropriate blending of a plurality of microcracked fiber reinforced cement composite materials (HPFRCC) that simultaneously realize high tensile strain performance after curing and low shrinkage, When the strain is 1% or more, it means that a crack dispersion type fracture phenomenon in which a large number of cracks (multi-cracks) are generated in a direction substantially perpendicular to the loading direction (stress direction). Various research studies have been conducted to realize the Steady State Cracking phenomenon (SSC phenomenon), which is the cause of multi-cracking, with PVA fibers. When the properties of the PVA fibers used and the properties of the matrix are successfully combined, Even so, a high toughness FRC (Fiber Reinforced Concrete) material having a tensile strain of 1% or more, preferably 2% or more can be obtained.

  Further, the PVA short fiber F1 is added to a matrix of a formulation having a water cement ratio (W / C × 100) of 25% or more and a sand cement ratio (S / C) of 1.5 or less (including 0). More than 3 vol.% Or less of the blended amount randomly distributed in the three-dimensional direction, and the PVA fiber F2 has a water cement ratio (W / C × 100) of 25% or more and a sand cement ratio (S / When the dispersion matrix is randomly dispersed in the three-dimensional direction at a blending amount of 1 to 3 vol.% In a matrix with a blend of C) of 1.5 or less (including 0), a crack-dispersed high toughness FRC material Is obtained.

  In the present invention described in claim 4, the plural fine crack type fiber reinforced cement composite material is continuous from the dam body upstream side slope to the top of the dam body, and the present invention described in claim 5 is provided with the plural fine crack type fiber reinforced cement reinforcement. The cement composite material is continuous from the slope on the upstream side of the dam body to the top of the dam body, and is continued to the bottom of the dam body. However, the gist of the plural fine crack type fiber reinforced cement composite material is to continue from this low portion to the bottom of the dam body.

  According to the present invention as set forth in claims 4 to 6, even if the overtopping should occur, the breakage of the levee body can be prevented.

  The gist of the present invention described in claim 7 is to form a predetermined roughness on the surface of the multiple fine crack type fiber reinforced cement composite material.

  According to the seventh aspect of the present invention, even when a coating layer is further provided on the multiple fine crack type fiber reinforced cement composite material, the adhesion can be enhanced by forming a predetermined roughness.

The gist of the present invention described in claim 8 is to form an environmental porous concrete layer capable of further greening on the coating layer of a plurality of fine crack type fiber reinforced cement composite materials (HPFRCC).

    According to the eighth aspect of the present invention, when the surface of the levee body is greened, the porous concrete has a high porosity, so that vegetation is easily formed, and the restoration of the ecosystem can be achieved along with the restoration of the vegetation.

  As described above, the covering structure of the surface of the levee body according to the present invention can be expected to have high durability to the dam body after repair, and in particular, can be expected to have high weather resistance even in the air. The excellent mechanical properties of the fine cracked fiber reinforced cement composite (HPFRCC) can improve stability during earthquakes.

  Furthermore, when it is for water storage, the required levee body stability can be ensured without expanding the site of the existing pond. In addition, the required levee body stability can be ensured while securing the reservoir water volume, and the embankment material required for renovation of the pond can be reduced.

  Moreover, even when embankment is required, a material having high shear strength can be used regardless of water shielding, and maintenance work using heavy machinery or a scoop can be performed on the renovated dam body.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal side view showing an embodiment of a covering structure for a surface portion of a levee body according to the present invention, in which 9 is a dam body for water storage.

  In this embodiment, the dike body 9 for water storage is for forming a pond for agriculture.

  In the present invention, as the covering structure of the levee body 9, a water permeable material which is a porous concrete having a water permeability coefficient larger than 10 (−2), in which a plurality of fine crack type fiber reinforced cement composite materials (HPFRCC) 8 are disposed in the lower part. The material 5 was brought into surface contact and bonded to form a laminated structure.

  The thickness of the multiple fine crack type fiber reinforced cement composite material (HPFRCC) 8 is set to 05 mm to 50 mm, and the thickness of the porous concrete is set to about 100 mm.

  Multiple fine cracked fiber reinforced cement composites (HPFRCC: High Performance Fiber Reinforced Cementitious Compositions) 8 are also abbreviated as high tough concrete, but short fibers are mixed in the mortar matrix by about 1 to 2% by volume. Shows strain hardening behavior in which the stress does not decrease to a strain of about 1 to 2% even after the first crack is generated under tensile stress, and a number of fine cracking properties called multiple cracking properties. It has the characteristic that cracks occur in a dispersed manner.

  As shown in FIG. 3, a composite material (DFRCC: Ductile Fiber Reinforced Compositions) in which fibers are mixed in cement can transmit stress by bridging the fibers at the crack surface, and can add a shear reinforcement effect to the member. However, a multi-fine crack type fiber reinforced cement composite material (HPFRCC) is represented by a crack-dispersed fiber reinforced cement composite material (ECC).

As the crack-dispersion type fiber-reinforced cement composite material 4, for example, a material obtained by improving a low shrinkage strain-hardening cement composite material having a self-filling property described in Japanese Patent Application Laid-Open No. 2003-192421 is used. That is, in the present invention, 1 vol. Of PVA (Poly Vinyl Alcohol) short fiber satisfying the following [F1] is added to the cement preparation matrix satisfying the following [M1]. % Or more 3 vol. % Is a crack-dispersed fiber-reinforced cement composite material blended in a blending amount of not more than%.
[M1]
Weight percentage of water binder (W / C): 25% or more Weight ratio of fine aggregate to binder (S / C): 1.5 or less Unit amount of water: 250 to 450 Kg / m ³
Air volume immediately after kneading: 3.5-20%
High-performance AE water reducing agent: less than 30 kg / m ³ [F1]
Fiber diameter: 0.05 mm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500-2400 MPa

The vinylon short fiber satisfying the condition of [F1] is preferably a short fiber having an elastic modulus equal to or higher than that of concrete produced using polyvinyl alcohol resin as a raw material, and a typical tensile strength is 90 kgf. A known material (manufactured by Kuraray Co., Ltd.) having a / cm ² class, an elastic modulus (Young's modulus) of 2900 kgf / mm ² class, a specific gravity of about 1.3 and a shape of 0.66 mmφ × 30 mm can be used.

  The blending amount of vinylon short fibers is 1 vol. If it is less than%, the yield strength after cracking is not sufficient, and the purpose of repairing the bank cannot be fully achieved. On the other hand, the blending amount of the vinylon short fiber is 3.0 vol. When the amount exceeds 20%, it becomes difficult to satisfy the fluidity necessary for construction.

  Moreover, as a high performance AE water reducing agent used in the high toughness FRC material, polycarboxylic acid type, polyether type, naphthalene type, melamine type, aminosulfonic acid type and the like can be used. Of these, those based on polycarboxylic acid or polyether are preferred.

  Porous concrete is a special concrete that is mainly made by adding coarse aggregate to cement paste and contains many continuous voids. Unlike ordinary solid concrete, it has water permeability and breathability.

  The porous concrete used in the present invention secured a water permeability coefficient larger than 10 (−2) in terms of the size of the coarse aggregate.

Next, the construction procedure will be described. In the present invention, porous concrete is first constructed, and the construction procedure is as follows.
(1) Installation of anti-suction sheet 19 (2) Installation of porous concrete form (3) Installation of winch (4) Unloading of porous concrete from agitator vehicle (5) Confirmation of amount of paste drop (6) Porous concrete (7) Compaction of porous concrete (8) Compaction of the end (9) Sprinkling curing after placing the porous concrete (10) Curing mat + Sprinkling (11) Curing mat 10 sprinkling 10 Blue sheet

Next, construction of a plurality of fine crack type fiber reinforced cement composite materials (HPFRCC) 8 is performed. The multiple fine crack type fiber reinforced cement composite material (HPFRCC) 8 will be described as a crack dispersion type fiber reinforced cement composite material (ECC).
(1) Sprinkling before ECC placement (2) Treatment of construction joints (Lath net)
(3) Manufacture and transportation of ECC base concrete (4) Unloading of ECC base concrete (5) On-site mixing of ECC (secondary mixing)
(6) Transportation of ECC (7) Leveling of ECC (8) Adjustment and compaction of ECC [Vessel bottom surface vibration]
(9) ECC input finishing (10) ECC curing [curing mat + watering + blue sheet]

  In order to carry out leveling of the crack-dispersed fiber reinforced cement composite material (ECC), the mortar flow value immediately after mixing is 165 mm or more, preferably 170 to 180 mm. If the thickness is less than 165 mm, the material may not be properly dispersed, and it may become impossible to spread uniformly.

However, if the flow value is too high, material separation may occur during pumping, and the fibers may aggregate to form fiber balls. In order to stably secure such a mortar flow value, a high performance AE water reducing agent of less than 30 kg / m ³ is blended, and the air amount immediately after mixing is 3.5 to 20%, preferably 10 to 20%. It is good to do. Furthermore, it is preferable to add a thickener to increase the material separation resistance while maintaining such fluidity. In particular, the use of a biopolymer for microbial fermentation such as welan gum (mixing about 0.01 to 0.2% with respect to the unit water amount) is beneficial.

  In order to secure an appropriate amount of powder, a part of the cement is replaced by an admixture such as fly ash or blast furnace slag, and the aggregate has a maximum particle size of 0.8 mm or less and an average particle size. It is preferable to use a fine aggregate of 0.4 mm or less. Therefore, it is preferable to add the requirements of the fine aggregate particle size: maximum particle size of 0.8 mm or less and average particle size of 0.4 mm or less as the condition of [M1]. And it is good to mix | blend so that the weight ratio (S / C) of this fine aggregate and binder may be 1.5 or less. The water binder ratio (W / C) needs to be 25% or more in order to improve the leveling workability.

  The crack-dispersed fiber reinforced cement composite material spread and leveled in this way has a tensile strain of 1 in a tensile test of a hardened material at the age of 28 days as long as the conditions [F1] and [M1] are satisfied. % Or more of the crack dispersion type high toughness FRC material layer. For this reason, the mechanism of crack generation is that innumerable minute cracks occur, and a crack with a large width does not occur.

  A plurality of fine crack type fiber reinforced cement composite material (HPFRCC) 8 which is the crack dispersion type fiber reinforced cement composite material (ECC) is continued from the upstream slope of the dam body 9 to the top 20 of the dam body 9.

  And it was made to continue to the bottom 7 of the dam body 9 downstream.

  In addition, a partially lower portion 21 is formed at the top portion 20 of the levee body 9 and is continued from the lower portion 21 to the bottom edge 7 downstream of the dam body 9.

  By doing in this way, even if it is over-topped, the breakage of the levee body can be prevented.

  Although illustration is omitted, a predetermined roughness is formed on the surface of the plurality of fine crack type fiber reinforced cement composite material 8.

The predetermined roughness is formed by surface treatment with blast or water jet.

  By doing in this way, even when providing a coating layer further on the multiple fine crack type fiber reinforced cement composite material 8, it is possible to improve adhesion.

FIG. 5 shows a second embodiment of the present invention, in which an environmental porous concrete layer 24 capable of further greening is formed on a coating layer of a plurality of fine crack type fiber reinforced cement composite materials (HPFRCC) 8.

  In porous concrete used as greening concrete, as coarse aggregate, No. 5 coarse aggregate (particle size 13 mm to 20 mm) or No. 6 coarse aggregate (particle size 5 to 13 mm) is often used.

  Greening porous concrete considering the habitat of living organisms is desired to have as large a void size as possible and to have a large amount of voids, fine aggregates including slag fine aggregate, powder containing cement, water, and necessary Porous concrete produced by kneading a mortar composed of an admixture used according to the conditions and coarse aggregate, and then curing and curing is preferred.

  Mortar (1) 100 parts by weight of powder containing 60% by weight or more of cement, (2) 50-200 parts by weight of fine aggregate containing 50% by weight or more of slag fine aggregate, and (3) 4% by weight of admixture. The total amount of water and admixture is 15 to 35 parts by weight, the upper limit of the proportion of the coarse aggregate is the actual volume ratio, and the lower limit is 10% less than the actual volume ratio. Yes, the blending ratio of mortar is such an amount that the porosity is 20 to 35%.

  The coarse aggregate is not particularly limited, and general coarse aggregate for concrete can be used. For example, river gravel, land gravel, crushed stone, etc. can be used. As for the particle size of the coarse aggregate, when producing porous concrete having a high void ratio and a large void diameter, it is usually preferable to use one having a maximum dimension of about 25 mm or more. May be smaller, a coarse aggregate having a particle size smaller than this may be used.

  As the cement, hydraulic cement such as Portland cement and mixed cement specified in JIS can be used. In addition, other powders such as fly ash, blast furnace slag powder, silica fume, limestone powder, and quartzite powder can be used as necessary. In the present invention, a total of cement and other powders used as necessary is used as the powder. The proportion of cement in the powder is preferably about 60% by weight or more.

  As the fine aggregate, slag fine aggregate was used. Any slag fine aggregate may be used as long as it exhibits latent hydraulic properties, and a blast furnace slag fine aggregate defined by JIS A 5011 is particularly preferable. The slag fine aggregate can also be used in combination with common fine aggregates such as river sand, land sand, sea sand, and crushed sand. In the present invention, as the fine aggregate, those that pass 85% by weight or more of a 5 mm sieve specified by the Japan Society of Civil Engineers can be used.

  The proportion of the slag fine aggregate contained in the fine aggregate is preferably in the range of about 50 to 100% by weight, and the strength of the porous concrete tends to increase as the proportion of the slag fine aggregate increases.

  Furthermore, various admixtures such as a water reducing agent, an AE agent, an AE water reducing agent, a high performance water reducing agent, and a high performance AE water reducing agent can be used as necessary.

The environmental porous concrete preferably has a porosity of about 20 to 35%, i.e., there are about 200 to 350 liters of voids in 1 m ^{3 of} concrete. If the porosity is too low, a sufficient amount of continuous voids cannot be formed, which is inappropriate as greening concrete. On the other hand, if the porosity is too high, the amount of mortar will be insufficient, and a sufficient strength cannot be obtained, which is not preferable.

Therefore, in the environmental porous concrete, the remainder excluding the coarse aggregate and the voids is the volume of mortar composed of powder, fine aggregate, water, and an admixture used as necessary. Normally, depending on the type of coarse aggregate used, the total amount of powder, fine aggregate, water and admixture is contained in 1 m ^{3 of} concrete in the range of about 60 to 250 liters.

It is a vertical side view which shows 1st Embodiment of the covering structure of the embankment surface layer part of this invention. It is a vertical side view of the covering structure of the dyke surface layer part for water storage which shows the comparative example with the covering structure of the dyke surface layer part of this invention. It is explanatory drawing of a multiple fine crack type fiber reinforced cement composite material (HPFRCC). It is a perspective view of the principal part of the covering structure of the bank body surface layer part of this invention. It is a perspective view of the principal part which shows 2nd Embodiment of the covering structure of the embankment surface layer part of this invention. It is a vertical side view which shows a prior art example.

DESCRIPTION OF SYMBOLS 1 ... Semi-permeable civil engineering sheet 2a, 2b ... Synthetic fiber cotton layer 3 ... High density flat cloth 4 ... Waterproof sheet 5 ... Water-permeable material 6 ... Method shoulder 7 ... Method bottom 8 ... Multiple fine crack type fiber reinforced cement composite material ( HPFRCC)
DESCRIPTION OF SYMBOLS 9 ... Dike body 10 ... Concrete 11 ... Top edge 12 ... Back slope 13 ... River water 14 ... River bed 15 ... Steel sheet pile 16 ... Steel ridge 17 ... Foundation concrete 18 ... Core soil 19 ... Suction prevention sheet 20 ... Top 21 ... Low Location 23 ... Guest soil 24 ... Environmental porous concrete layer

Claims (8)

  Multi-cracked fiber reinforced cement composite material (HPFRCC) is bonded in surface contact with a water-permeable material which is a porous concrete having a water permeability coefficient larger than 10 (−2), which is disposed in the lower part of the composite structure. The covering structure of the surface layer part of a dam body characterized by this.   The covering structure for a surface portion of a levee body according to claim 1, wherein the dam body is for storing water and is a pond body for agricultural use. The cement composite material contains 1 vol. Of PVA (Poly Vinyl Alcohol) short fibers satisfying the following [F1] in a cement preparation matrix satisfying the following [M1]. % Or more 3 vol. The covering structure of a levee body surface layer portion according to claim 1 or 2, wherein the covering structure is a crack dispersion type fiber-reinforced cement composite material blended in a blending amount of not more than%.
[M1]
Weight percentage of water binder (W / C): 25% or more Weight ratio of fine aggregate to binder (S / C): 1.5 or less (including 0)
Unit water quantity: 250-450 kg / m ³
Air volume immediately after kneading: 3.5-20%
High-performance AE water reducing agent: less than 30 kg / m ³ [F1]
Fiber diameter: 0.05 mm or less Fiber length: 5-20 mm
Fiber tensile strength: 1500-2400 MPa   The covering structure of the levee body surface layer part according to any one of claims 1 to 3, wherein the plurality of fine crack-type fiber reinforced cement composite materials are continuous from the slope on the upstream side of the dam body to the top of the dam body.   The bank according to any one of claims 1 to 3, wherein the plurality of fine crack-type fiber reinforced cement composite materials are continuous from the slope on the upstream side of the bank body to the top of the bank body and are continued to the bottom of the slope downstream of the bank body. Body surface layer covering structure.   The covering structure of the levee body surface layer part according to claim 5, wherein a part of the levee body top part is formed at a low part, and the plurality of fine crack type fiber reinforced cement composite materials are continuously connected from the low part to the bottom of the dam body.   The covering structure of the levee body surface layer part according to any one of claims 1 to 6, wherein a predetermined uneven roughness is formed on a surface of the multiple fine crack type fiber reinforced cement composite material. The covering structure of the levee body surface layer portion according to any one of claims 1 to 7, wherein an environmental porous concrete layer capable of surface greening is further formed on the covering layer of a plurality of fine crack type fiber reinforced cement composite materials (HPFRCC). .

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