JP4113445B2 - Slope fill method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for embedding in order to prevent collapse of a natural ground on a slope of a side of a mountain road or the like, and more specifically, a method of embedding intended to facilitate transportation and construction work by reducing the weight of a material. It is about.
[0002]
[Prior art]
Conventionally, as the slope embankment method, rectangular panel-like residual molds are stacked vertically and horizontally, and the frame is arranged vertically and horizontally to face this residual mold, and the separator between the residual mold and the frame is separated A lightweight embankment method has been proposed in which both are erected while being connected together and a cement-based air bubble mixed lightweight soil is placed between the remaining formwork made of concrete and the natural ground (see Patent Document 1). In addition, as a method of using the remaining formwork, a steel frame for a column is erected on the mat, a frame-shaped concrete precast formwork is placed outside the steel frame, and concrete is placed in the precast buried formwork. A construction method has been proposed (see Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-242189.
[Patent Document 2]
Japanese Unexamined Patent Publication No. 2000-120982.
[0004]
[Problems to be solved by the invention]
However, since the remaining formwork used in the above construction method is made of concrete, there is a problem that the weight is large and the workability of embankment construction is poor, and it is difficult to convey it particularly in mountainous areas.
[0005]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a slope embankment method that achieves weight reduction of the remaining formwork, is easy to convey, and has good workability.
[0006]
[Means for Solving the Problems]
The slope embedding method according to the present invention is such that a plurality of support piles having groove portions are erected on the ground at predetermined intervals along the slope, and a plurality of remaining molds made of synthetic resin foam are placed over adjacent support piles. Is placed, the both ends thereof are fitted into groove portions, the same formwork is held by a support pile, and soil or concrete is placed in the space between the slope and the remaining formwork.
[0007]
Support piles are preferably placed on the anti-slope side so that the formwork does not fall in the anti-slope direction, i.e. the road side, before placing the concrete after placing the remaining form frame over the adjacent support piles. What is necessary is just to have a groove part which fits the both sides of a residual mold form so that the same formwork may not fall in the direction opposite to a surface after concrete placement so that it may not fall also to the surface side. As the support pile having the groove portion, H steel is suitable, but it may be an extruded material having a C-shaped section, a U-shaped section, or a Z-shaped section, or an L-shaped angle material.
[0008]
The remaining formwork is generally rectangular (for example, about 180 cm × about 90 cm) when viewed from the front and has a thickness of 1 to 10 cm, and a plurality of the remaining formwork are connected in the length direction of the pile across adjacent support piles. Be placed. A plurality of remaining molds can be used in the thickness direction.
[0009]
The bubbles in the remaining mold are preferably spindle-shaped having a major axis in the thickness direction. A preferable residual mold is composed of a composite sheet in which a core layer made of a polyolefin resin foam sheet is laminated with both surface layers made of a thermoplastic resin sheet sandwiching the core layer, and the density is 0.05 to 0.5 g. / Cc, and the average value of the aspect ratio Dz / Dxy of the bubbles inherent in the core layer is 1.1 to 5.0. Both surface layers are made of a stretched polyolefin resin sheet and are preferably laminated in two directions (orthogonal or other angles). A more preferable residual mold is formed by laminating a weather resistant film made of an aluminum vapor deposition film or the like on the surface of the composite sheet.
[0010]
The concrete is preferably a bubble-containing lightweight concrete. Such concrete is made by adding sand, mud, clay, or incinerated ash to the cement as an aggregate, mixing it with water, adding a foaming agent and mixing it with air, and foaming it. The mixture is cured after placement. Examples of the foaming agent include those mainly composed of a polymer surfactant, and those obtained by modifying polyvinyl alcohol, cellulose, alginic acid, animal protein, and the like are used. The mixing amount of the foaming agent is preferably 0.5 to 5% by weight with respect to the cement. Air-mixed lightweight concrete or soil containing a large amount of air foamed by such a foaming agent is placed in the space between the back of the remaining mold and the slope of the natural ground. The concrete and the remaining formwork are bonded with, for example, a hot melt adhesive. In this case, by providing irregularities on the surface of the thermoplastic resin sheet, it is possible to improve the adhesion with the remaining mold. Further, a sheet having good affinity with concrete such as paper may be laminated on the surface of the remaining mold.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
When the remaining mold is made of a composite sheet, the material of the foam sheet used as the core layer is a polyolefin resin, a homopolymer of an olefin monomer, or a copolymer of a main component olefin monomer and another monomer. Although not particularly limited, for example, polyethylene such as low-density polyethylene, high-density polyethylene, and linear low-density polyethylene, polypropylene such as homo-type polypropylene, random-type polypropylene, and block-type polypropylene, polybutene, and ethylene-propylene Copolymers mainly composed of ethylene such as copolymers, ethylene-propylene-diene terpolymers, ethylene-butene copolymers, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylate copolymers, etc. Polymers and the like, and two or more of these It may be a combination.
[0012]
As the polyolefin constituting the main component of the polyolefin resin, one or a combination of two or more of the above-described polyethylene and polypropylene is preferable.
[0013]
The polyolefin resin refers to a resin composition in which the ratio of the polyolefin is 70 to 100% by weight. Resins other than the polyolefin constituting the polyolefin resin are not limited, and examples thereof include polystyrene and styrene elastomer. If the proportion of polyolefin in the polyolefin resin is less than 70% by weight, not only the lightness, chemical resistance, flexibility, elasticity, etc. that are characteristic of polyolefin can be exhibited, but also the melt viscosity necessary for foaming can be secured. Since it may become difficult, it is not preferable.
[0014]
In the remaining mold, if the density of the polyolefin resin foam sheet exceeds 0.5, the weight of the mold becomes too heavy, the cost is high, the mold becomes impractical, and the density is 0.05 If it is less than 1, bending elasticity will be insufficient. A particularly preferred density is 0.06 to 0.15 g / cc.
[0015]
The term “core layer” used in the present specification means a layer including the central portion in the thickness direction of the foam sheet and not including both surface layers. For example, in the composite sheet having a sandwich structure shown in FIG. 3, the core layer (5) is a layer sandwiched by a pair of front and back surfaces (8) and (8).
[0016]
The average value of the aspect ratio Dz / Dxy of the bubbles inherent in the core layer made of the polyolefin resin foam sheet is 1.1 to 5.0, preferably 1.2 to 2.5.
[0017]
The term “aspect ratio” used in the present specification is the number (arithmetic) average value of the ratio of the maximum diameter in the fixed direction in the bubbles in the thermoplastic resin foam sheet, and the diameter Dz in the sheet thickness direction and the diameter in the in-plane direction. Expressed as the ratio Dz / Dxy to Dxy.
[0018]
That is, as shown in FIG. 4, an enlarged photograph (c) 10 times the arbitrary cross section (b) parallel to the sheet thickness direction (referred to as z direction) of the foam sheet (a) is taken. ) The following two constant direction maximum diameters (Dz, Dxy) in at least 50 bubbles randomly selected from the above are measured, and the number average value is calculated.
[0019]
Dz: the maximum diameter parallel to the z direction of the bubbles in the foam sheet
Dxy: the maximum diameter parallel to the sheet width or length direction of the bubbles in the foam sheet, that is, the plane direction perpendicular to the z direction (referred to as the xy direction)
[0020]
It is preferable that the average value of Dxy of the bubbles present in the core layer is 500 μm or more. As a result, when the foam sheet receives a compressive force in the thickness direction, a force is applied in the major axis direction to the spindle-shaped cell that is long in the thickness direction, so the foam sheet exhibits a high compressive strength in the thickness direction. .
[0021]
If the average aspect ratio is less than 1.1, the bubbles will be almost spherical, and the compression modulus and compression strength resulting from the spindle shape will not be improved, and it may not be able to withstand the pressure applied during concrete placement and deform. In addition, a formwork made of a three-layer sandwich structure of a core layer and both surface layers is insufficient in bending rigidity. When the average value of the aspect ratio exceeds 5.0, the mold is easily broken when subjected to an impact, resulting in insufficient durability.
[0022]
The foams constituting the core layer include those obtained by chemical foaming and those obtained by physical foaming. The former method is preferred for heat-sealing the resin sheet to the foam sheet.
[0023]
For foams by chemical foaming, a thermal decomposable chemical foaming agent that generates decomposition gas by heating is dispersed in the polyolefin resin composition in advance, and the resulting foamable composition is once shaped into a sheet-like raw fabric. Then, it can be produced by heating and foaming with a gas generated from the foaming agent. Representative examples of the thermal decomposition type chemical blowing agent include azodicarbonamide, benzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, toluenesulfonyl hydrazide, 4,4-oxybis (benzenesulfonyl hydrazide) and the like. The addition amount of the chemical foaming agent is preferably 2 to 20 parts by weight with respect to 100 parts by weight of the resin composition.
[0024]
The polyolefin resin constituting the polyolefin resin foam sheet preferably has a gel fraction of 5 to 35% by weight. The reason is that when the foam sheet and the resin sheet are fused by heat, the foam can be prevented from being softened or melted and greatly deformed. When the gel fraction exceeds 35% by weight, the fluidity at the time of remelting is lowered, and there is a high possibility that the recyclability will be adversely affected.
[0025]
The gel fraction is indicated by the weight fraction of the insoluble matter (gel) obtained by dissolving a sample of polyolefin resin foamed sheet in 120 ° C. hot xylene for 24 hours and separating and drying the sample.
[0026]
Next, a method for producing the foam sheet constituting the core layer will be described.
[0027]
The production method for obtaining the foam sheet is not particularly limited, but preferably, a polyolefin resin and a modifying monomer are melt-mixed to obtain a modified polyolefin, and a thermally decomposable chemical foaming agent is dispersed in the modified polyolefin. This is a method in which a foamable sheet is chemically foamed by heating the resulting foamable sheet to a temperature equal to or higher than the decomposition temperature of the thermally decomposable chemical foaming agent after once forming the base resin composition into a sheet-like raw material.
[0028]
The modifying monomer is a compound having two or more functional groups capable of radical reaction in the molecule. Examples of the functional group include an oxime group, a maleimide group, a vinyl group, an allyl group, and a (meth) acryl group. The modifying monomer is preferably a dioxime compound, a bismaleimide compound, divinylbenzene, an allyl polyfunctional monomer, or a (meth) acrylic polyfunctional monomer. The modifying monomer may be a cyclic compound having two or more ketone groups in the molecule, such as a quinone compound.
[0029]
By adopting the resin modification method as described above, it is possible to foam the foamed sheet at normal pressure despite the low degree of crosslinking of the molded foam sheet.
[0030]
As a method for shaping the sheet-like foamable raw material, methods generally performed in plastic molding processes such as press molding, blow molding, calendering molding, injection molding, etc. can be applied in addition to extrusion molding. A method of immediately forming a foamable resin composition discharged from a screw extruder is preferable from the viewpoint of productivity. In this method, a continuous original fabric sheet having a constant width can be obtained.
[0031]
The chemical foaming of the sheet-shaped original fabric is usually performed in a temperature range not lower than the decomposition temperature of the pyrolytic chemical foaming agent and not higher than the thermal decomposition temperature of the thermoplastic resin. In particular, as a continuous foaming apparatus, in addition to a take-off type foaming machine that foams while taking out a foam on the outlet side of a heating furnace, a belt type foaming machine, a vertical or horizontal type foaming furnace, a hot air thermostat, or a hot bath Foaming oil baths, metal baths, salt baths, etc. are used.
[0032]
In order to obtain a foam composed of the above-mentioned spindle-shaped bubbles, that is, a foam having an average aspect ratio Dz / Dxy of the bubbles of 1.1 to 5.0, foaming in the in-plane direction of the original fabric is performed during foaming. The foamed sheet is suppressed and foamed only in the thickness direction, and the foamed sheet is slightly compressed in the thickness direction before cooling. As a result, the foam bubbles have a spindle shape with the major axis oriented in the thickness direction.
[0033]
In order to suppress foaming in the in-plane direction of the original fabric during foaming, a thermoplastic resin sheet such as a nonwoven fabric made of a thermoplastic resin is laminated as a surface layer on both sides of the original fabric before foaming. It is also possible to heat-seal the thermoplastic resin sheet with the polyolefin resin foam.
[0034]
As shown in FIG. 3, a typical example of the composite sheet constituting the remaining mold is a polyolefin resin foam sheet as a core layer (5), and a thermoplastic resin sheet is laminated on both sides as a surface layer (8). In addition, a composite sheet in which the polyolefin resin stretched sheets (6) are bonded to the outer surfaces of both surface layers (8) by thermal fusion, respectively.
[0035]
Although the kind of resin which comprises a thermoplastic resin sheet is not limited, It is preferable from a viewpoint of joining and recycling that it is polyolefin resin similar to a foam sheet. The dimensions including the thickness of the resin sheet, the surface form, the molding method, etc. are not limited. The joining of the core layer made of the foam sheet and the both surface layers made of the thermoplastic resin sheet is preferably achieved by thermal fusion from the viewpoint of recycling.
[0036]
In the residual mold, a particularly preferable surface layer is a sheet made of a thermoplastic resin sheet, particularly a stretched sheet made of a polyolefin resin.
[0037]
Next, the stretched polyolefin resin sheet will be described.
[0038]
The linear expansion coefficient of the stretched polyolefin resin sheet is 5 × 10 ^-Five (1 / ° C.) or less, preferably 3 × 10 ^-Five (1 / ° C.) or less, more preferably 2 × 10 ^-Five (1 / ° C.) or less and −2 × 10 ^-Five (1 / ° C.) or higher. Here, the linear expansion coefficient is a scale indicating the rate at which the size of a substance expands with temperature. As a method of measuring the linear expansion coefficient, there is a method of precisely measuring the size of a substance being heated by TMA (mechanical analysis). In the present invention, as shown in the examples described later, The coefficient of linear expansion is simply calculated from the difference in dimensions at 80 ° C.
[0039]
The stretched polyolefin resin sheet is not particularly limited, but generally the linear expansion coefficient of the polyolefin resin sheet is 5 × 10. ^-Five Since it is higher than (1 / ° C.), it is subjected to a treatment such as stretching or rolling to give a coefficient of linear expansion of 5 × 10 ^-Five A polyolefin-based resin stretched sheet set to (1 / ° C.) or less is used. In the polyolefin-based resin stretched sheet subjected to such treatment, the linear expansion coefficient decreases as the stretch ratio is increased.
[0040]
The foam sheet of the composite sheet itself is approximately 5 × 10 ^-Five ~ 15 × 10 ^-Five Although a linear expansion coefficient of (1 / ° C.) is shown, by laminating the surface layer on both surfaces of the foam sheet, thermal expansion and contraction is suppressed, and as a result, a residual mold having a low linear expansion coefficient is obtained.
[0041]
The linear expansion coefficient is important for the following reason. Generally, when concrete is placed inside a concrete formwork, heat of hydration is generated along with the hydration reaction of cement, and the formwork reaches 60 ° C. or more. For this reason, the plastic mold is not only softened by the heat, but is also thermally expanded to cause warping. The stretched polyolefin resin sheet has a large tensile strength and tensile modulus in the stretching direction. In a three-layer laminate in which the foam sheet having high compression rigidity is used as a core material and sandwiched between the stretched sheets, a sandwich structure is formed, so that bending rigidity and bending strength are dramatically improved.
[0042]
The polyolefin resin constituting the stretched polyolefin resin sheet is not particularly limited, and for example, low density polyethylene, linear low density polyethylene, high density polyethylene, homopolypropylene, block polypropylene and the like can be used. In consideration of the elastic modulus after stretching, it is preferable to use polyethylene having a high theoretical elastic modulus, and high density polyethylene having high crystallinity is particularly preferable.
[0043]
The molecular weight of the polyolefin for the stretched sheet is not particularly limited, but preferably a polyolefin having a weight average molecular weight of 500,000 or less is used. When the weight average molecular weight exceeds 500,000, when obtaining a stretched polyolefin resin sheet, it becomes difficult to form a stretched raw sheet, and the stretchability is also deteriorated, and high-stretch stretching may be impossible. In addition, although the minimum of the weight average molecular weight of polyolefin resin is not specifically limited, When it becomes smaller than 100,000, since resin itself becomes weak, stretchability may be impaired. Accordingly, polyolefins having a weight average molecular weight in the range of 100,000 to 500,000, particularly high density polyethylene, are preferred.
[0044]
As a method for measuring the weight average molecular weight, a sample is dissolved in a heated solvent such as o-dichlorobenzene, and then the solution is injected into a column and the elution time is measured. A method of measuring by a so-called gel permeation chromatography method (high temperature GPC method) is common, and the weight average molecular weight measured by this method is also described in this specification.
[0045]
In consideration of the range of the weight average molecular weight from the melt index (hereinafter abbreviated as MI), those having MI in the range of about 0.1 to 20 are preferable. If the MI is out of this range, it may be difficult to stretch at a high magnification. MI refers to an index representing the melt viscosity of a thermoplastic resin limited to JISK 6760.
[0046]
Next, a method for producing a stretched polyolefin resin sheet will be described.
[0047]
Linear expansion coefficient 5 × 10 ^-Five The method for producing a polyolefin resin stretched sheet of (1 / ° C.) or less is not particularly limited, but it is preferable to subject the polyolefin resin sheet to stretching or rolling.
[0048]
In obtaining the above-mentioned stretched polyolefin resin sheet, a crosslinking aid, a radical photopolymerization initiator, and the like may be added to the polyolefin as necessary. Examples of the crosslinking aid include polyfunctional monomers such as triallyl cyanurate, trimethylolpropane triacrylate, and diallyl phthalate. Examples of the photoradical polymerization initiator include benzophenone, thioxanthone, and acetophenone. it can. The addition amount of these crosslinking assistants and radical photopolymerization initiators is not particularly limited, but in order to allow the crosslinking to proceed rapidly, the polyolefin resin constituting the stretched polyolefin resin sheet is usually 100 weight. It is preferable to set it as the range of 1.0-2.0 weight part with respect to a part.
[0049]
The method for obtaining the polyolefin-based resin sheet before stretching is not particularly limited, and after the polyolefin-based resin described above is plasticized with an extruder or the like, it may be extruded into a sheet through a sheet die and cooled. it can. The thickness of the polyolefin resin sheet before stretching is preferably in the range of 0.5 to 4 mm. If the thickness is less than 0.5 mm, the sheet thickness after stretching becomes too thin, and the strength may be insufficient during handling. If the thickness exceeds 4 mm, stretching may be difficult.
[0050]
Moreover, when the polyolefin resin sheet before extending | stretching obtained as mentioned above is extended | stretched and a polyolefin resin stretched sheet is obtained, a draw ratio is set so that said linear expansion coefficient may be satisfy | filled. Specifically, this draw ratio is in the range of 5 to 40 times, preferably 20 to 40 times. When the stretching is less than 5 times, the linear expansion coefficient does not decrease, and the effect of increasing the mechanical strength (tensile property) may be small regardless of the type of polyolefin resin. When the draw ratio exceeds 40 times, it may be difficult to control the drawing operation.
[0051]
Although the extending | stretching temperature for obtaining a polyolefin resin extending | stretching sheet is not specifically limited, It is preferable to set it as the range of 85-120 degreeC. If the stretching temperature is less than 85 ° C., the stretched sheet is likely to be whitened and high-strength stretching may be difficult.
[0052]
Although the stretching method is not particularly limited, a normal uniaxial stretching method, particularly a roll stretching method is used. The roll stretching method is a method in which an original fabric to be stretched is sandwiched between two pairs of rolls having different speeds, and the film is pulled while being heated, and can be strongly molecularly oriented only in the uniaxial stretching direction. In this case, the speed ratio of the two pairs of rolls becomes the draw ratio.
[0053]
In the case of a relatively thick sheet, smooth stretching may be difficult only by the roll stretching method. In such a case, roll rolling may be performed prior to roll stretching. The roll rolling process is performed by inserting a stretched raw material thicker than the interval between the rolling rolls between a pair of rolling rolls rotating in opposite directions to reduce the thickness of the raw fabric and at the same time extend it in the length direction. Done. Since the roll-rolled sheet has been subjected to orientation treatment in advance, it is smoothly stretched in the uniaxial direction by the next roll stretching.
[0054]
In order to achieve a predetermined stretching temperature in the stretching step, the preheating temperature, roll temperature and / or atmospheric temperature of the sheet may be adjusted.
[0055]
The above-mentioned stretched polyolefin resin sheet may be subjected to a crosslinking treatment in order to increase heat resistance, or to increase heat resistance and creep resistance of the final polyolefin molded body. Crosslinking can be performed by electron beam irradiation or ultraviolet irradiation.
[0056]
Although the electron beam irradiation amount varies depending on the composition and thickness of the stretched polyolefin sheet to be used, it is generally 1 to 20 Mrad, preferably 3 to 10 Mrad. Moreover, when bridge | crosslinking by electron beam irradiation, if a crosslinking adjuvant is added to the polyolefin stretched sheet, bridge | crosslinking will advance smoothly.
[0057]
The amount of UV irradiation is usually 50 to 800 mW / cm ² , Preferably 100 to 500 mW / cm ² It is said. In the case of crosslinking by ultraviolet irradiation, the crosslinking can be easily performed by adding a photopolymerization initiator and a crosslinking assistant.
[0058]
The degree of crosslinking is preferably such that the gel fraction measured by the measurement method described later is about 50 to 90%.
[0059]
The method for laminating the stretched polyolefin resin sheet on the polyolefin resin foam sheet is not particularly limited, and examples thereof include adhesion with an adhesive and heat fusion by heating, and heat fusion is preferably used.
[0060]
When the polyolefin resin stretched sheet is heat-sealed with the polyolefin resin foam sheet, a surface treatment or a primer may be used. A method in which a polyolefin resin film having a melting point equal to or lower than the temperature at which the polyolefin resin stretched sheet is thermally deformed is interposed between the two.
[0061]
Further, the lamination direction of the polyolefin resin stretched sheet is not particularly limited, but the mechanical properties in the stretched direction are particularly improved, so that the sheet can be unidirectional or bi-directional (orthogonal or otherwise) depending on the application to be used. (Angle) etc. are preferable. Further, the number and thickness of the sheets to be laminated are also appropriately determined according to the target mechanical properties.
[0062]
The heating and pressurizing conditions at the time of heat-sealing differ depending on the polyolefin-based resin stretched sheet to be used, and thus cannot be uniquely determined, but usually 0.1 to 5 kg / cm. ² A pressure in the range of 5 and a temperature not higher than the melting point of the polyolefin resin are preferable. If the pressure is outside the above range, the shape of the laminate may be disturbed during molding, and if the heating temperature during bonding exceeds the melting point of polyolefin, the shape of the laminate may be disturbed due to shrinkage or the like during molding. And may adversely affect the linear expansion coefficient.
[0063]
A more preferable form of the remaining mold is a polyolefin resin sheet in which both surface layers of the remaining mold are reinforced with inorganic fibers.
[0064]
The inorganic fiber reinforced polyolefin resin sheet preferably satisfies a flexural modulus of 3.5 GPa or more and a flexural strength of 120 MPa or more.
[0065]
As in the case of the stretched sheet described above, the bending rigidity and the bending strength are remarkably improved in the mountain-layer laminate formed by sandwiching the foam sheet having a high compression rigidity as a core material.
[0066]
The remaining formwork is deformed by the concrete side pressure when the concrete is placed. In general, the deformation of the formwork panel is caused by warping due to bending stress in the intermediate portion of the panel length in addition to the local compressive deformation of the temporary reinforcing member.
[0067]
The remaining formwork can be considered as a continuous beam in the calculation, and its deflection can be estimated to be about 1/2 of that of a simple beam, and its stress can be estimated to be about 1/3 of that of a simple beam. That is, since the generated warp varies depending on the interval between the temporary reinforcing members, the mechanical properties of the panel are not uniquely determined. However, there is no practical problem as long as one of the above performances is satisfied.
[0068]
The reinforcing inorganic fibers are mainly glass fibers or carbon fibers, but any fiber can be used as long as the same performance can be secured. Glass fibers are advantageous from the viewpoint of cost, and long fibers are particularly preferable because they can ensure mechanical properties. The fiber thickness, length, filling amount, fiber arrangement, surface treatment, and the like may be appropriately determined depending on the mechanical properties and moldability of the resin sheet that should contain inorganic fibers.
[0069]
A preferable filling amount of the inorganic fiber is 30 to 70% by weight. If the amount is too small, the elastic modulus and the holding power of the nail tend to be insufficient. If the amount is too large, the workability and surface properties as a mold may be deteriorated.
[0070]
The polyolefin resin used for the inorganic fiber reinforced polyolefin resin may be the same as the polyolefin resin used for the above-mentioned polyolefin resin foam sheet, and polypropylene is particularly advantageous from the viewpoint of strength, elastic modulus, and heat resistance. is there.
[0071]
The polyolefin resin may contain an inorganic filler such as calcium carbonate or talc for the purpose of further improving mechanical properties.
[0072]
In a particularly preferable method for producing a resin sheet, a three-layer laminate formed by sandwiching a glass nonwoven fabric with a polypropylene sheet is compression-molded after heating. This multilayer resin sheet has excellent surface properties because both surface layers are made of polypropylene. A five-layer or seven-layer laminate is also effective.
[0073]
Further, it is recognized that a glass nonwoven fabric mixed with fibers made of polyolefin resin such as polypropylene contributes to improvement of strength.
[0074]
Examples of the method of laminating and bonding the inorganic fiber reinforced polyolefin resin sheet to the polyolefin resin foam sheet include adhesion with an adhesive and heat fusion by heating, but heat fusion is also preferable. When heat-sealing both, surface treatment or a primer may be used.
[0075]
When using the multilayer resin sheet containing the said glass nonwoven fabric, after preheating, shaping | molding of a multilayer resin sheet and the heat sealing | fusion of the same sheet and a foam sheet can be performed simultaneously within the type | mold of a compression molding machine.
[0076]
Another preferred form of the remaining mold is one in which a thin fiber molded sheet is interposed between the core material and both surface layers.
[0077]
Here, the term “thin” has a relative meaning and means a thickness of about 10% with respect to the thickness of the polyolefin resin foam sheet.
[0078]
Examples of such fiber-molded sheets include fibers made of synthetic resins such as polyester, nylon, vinylon, polycarbonate, acrylic, and polyolefin, woven fabrics and non-woven fabrics using natural fibers, cold chills, and inorganic materials such as glass fibers and carbon fibers. A sheet made of fibers can be selected.
[0079]
The method of heat-sealing the fiber molded sheet and the foam sheet is not particularly limited, but the fibers disposed on both sides of the foam sheet and the foam sheet before foaming, at the same time as foaming, or at the time of cooling and solidification are produced. A method in which a suitable pressure is applied to the sandwich body with the molded sheet and these are laminated by pressure bonding is advantageous in terms of energy.
[0080]
By laminating a fiber molded sheet on the foam sheet, the flexural rigidity of the foam sheet can be freely controlled, and when joining the resin sheet, an anchor effect works in the case of thermal fusion, and an adhesive is used. In some cases, chemical polarity is imparted, and in any case, it is possible to achieve strong adhesion.
[0081]
【Example】
Next, the present invention will be specifically described based on examples. Moreover, the manufacture example of the composite sheet which comprises a residual mold form is shown as a reference example.
[0082]
In FIGS. 1 to 3, a plurality of H steels (1) as support piles having a groove are placed on the ground (3) between the slope (2) and the road at intervals of about 180 cm along the slope (2). Type in. The height of the ground part of H steel (1) is almost equal to the height of slope (2). Steel H (1) is about 10 cm in width and length. The remaining mold (4) made of synthetic resin foam is arranged over the adjacent H steel (1), and both sides thereof are fitted into the groove (1a) of the H steel (1). The remaining mold (4) is rectangular (180 cm × 90 cm) when viewed from the front and has a thickness of 5 cm, and a plurality of the remaining molds (4) are arranged in series in the length direction of the piles across adjacent support piles. By fitting both sides of the remaining formwork (4) into the groove (1a) of the H steel (1), the remaining formwork (4) will not fall on the opposite side, that is, the road side or the slope side. Has been made.
[0083]
The remaining formwork (4) has a thermoplastic resin sheet laminated as a surface layer (8) on both sides of a core layer (5) made of a polyolefin resin foam sheet, and the polyolefin resin stretched on the outer surfaces of both surface layers (3). This is a composite sheet (1) in which the sheet (6) is bonded by thermal fusion. This composite sheet has a density of 0.15 g / cc and has an average value 2.2 of the aspect ratio Dz / Dxy of the bubbles in the core layer. The stretched sheet (6) is a super stretched sheet laminated in an orthogonal shape. A weather resistant film (7) made of an aluminum vapor deposition film is further laminated on the surface of the composite sheet (surface on the opposite side).
[0084]
A lightweight concrete (8) containing bubbles is placed in the space between the back of the remaining formwork (4) supported by the H steel (1) and the slope (2) of the natural ground. For lightweight concrete containing foam (8), sand, mud, clay, incinerated ash, etc. are added to the cement as an aggregate, mixed with water, added with a polymer surfactant as a foaming agent, and mixed with air. This is a foamed mixture obtained by foaming.
[0085]
Reference example 1
(1) Preparation of modified polyolefin resin
As a screw extruder for modification, BT40 (Plastics Engineering Laboratory Co., Ltd.) same direction rotating twin screw extruder was used. This is equipped with a self-wiping double thread, L / D is 35 and D is 39 mm. The cylinder barrel is composed of first to sixth barrels from the upstream side to the downstream side of the extruder, the die is a three-hole strand die, and a vacuum vent is installed in the fourth barrel in order to collect volatile matter.
[0086]
The operating conditions are as follows.
[0087]
・ Cylinder barrel set temperature: 220 ℃
・ Screw rotation speed: 150rpm
[0088]
First, polyolefin resin is charged into the extruder from the rear end hopper into the modification screw extruder configured as described above, and a mixture of the modification monomer and the organic peroxide is injected into the extruder from the third barrel and melted. By mixing, a modified resin was obtained. At this time, the volatile matter generated in the extruder was evacuated by a vacuum vent.
[0089]
Polyolefin-based resin is a polypropylene random copolymer (Mitsubishi Chemical "Novatech PP EG7", MI: 1.7 g / 10 min, density: 0.9 g / cm ^Three The supply amount was 100 kg / h. The modifying monomer was trimethylpropane trimethyl acrylate, and the supply amount was 1200 g / h.
[0090]
A modified resin obtained by melt blending of a polyolefin resin and a modifying monomer was discharged from a strand die, cooled with water, and cut with a pelletizer to obtain modified resin pellets.
[0091]
(2) Preparation of foamable resin composition
The blowing agent kneading screw extruder is a TEX-44 type (manufactured by Nippon Steel Works) co-rotating twin screw extruder, which is equipped with a self-wiping twin screw, whose L / D is 45.5, D Is 47 mm. The cylinder barrel is composed of first to twelfth barrels from the upstream side to the downstream side of the extruder, and the forming die is a T die having an outlet width of 700 mm.
[0092]
As a sheet cooling and shaping apparatus, a cooling apparatus (manufactured by Sekisui Koki Co., Ltd.) composed of three cooling rolls having a diameter of 220 mm and a width of 1000 mm was provided downstream of the foaming agent kneading screw extruder.
[0093]
The temperature setting categories are as follows.
[0094]
The first barrel is always cooled
1st zone; 2-4 barrels
2nd zone; 5-8 barrels
3rd zone; 9th to 12th barrels
Zone 4; die and adapter section
[0095]
A side feeder is installed in the sixth barrel for supplying the foaming agent, and a vacuum vent is installed in the eleventh barrel for recovering volatile components.
[0096]
The operating conditions are as follows.
[0097]
Cylinder barrel set temperature: 220 ° C upstream
: 170 ° C downstream from the side feeder
-Screw rotation speed: 50rpm
[0098]
The modified resin obtained as described above was supplied at a supply rate of 100 kg / h to a foam extruder kneading screw extruder. Moreover, the foaming agent was supplied to the same extruder from the side feeder. The blowing agent was azodicarbonimide (ADCA), and the supply amount was 6.0 kg / h. Thus, a foamable resin composition was obtained by kneading the modified resin and the foaming agent.
[0099]
(3) Preparation of polyolefin resin foam sheet
This foamable resin composition was extruded from a T-die to obtain a polyolefin resin foamable sheet having a width of 350 mm and a thickness of 0.5 mm.
[0100]
(4) Preparation of composite sheet
This polyolefin resin foamable sheet was passed through three cooling rolls of the cooling device. At that time, on both front and back sides of the foamable resin composition sheet, a polyethylene terephthalate nonwoven fabric (manufactured by Toyobo Co., Ltd., “Spunpond Ecule 6301A”, weighing 30 g / m) ² ) And using a press molding machine, the temperature is 180 ° C., the pressure is 19.6 MPa (200 kgf / cm). ² ) To obtain a continuous foamable composite sheet having a thickness of 0.6 mm.
[0101]
(5) Foam
A double belt type foaming machine (manufactured by Kyowa Engineering Co., Ltd.) having a total length of 6 m and comprising three zones of preheating, foaming and cooling and two upper and lower belts was prepared. The foaming machine is provided with a 2-inch transport roll in each of the preheating zone and the foaming zone, and a 4-inch cooling water circulation roll in the cooling zone.
[0102]
The preheating zone was set to 170 ° C., the foaming zone was set to 210 ° C., the surface temperature of the cooling roll was set to 25 ° C., and the foamable composite sheet as a raw fabric sheet was supplied to the foaming machine.
[0103]
The sheet feeding linear velocity was set at 0.5 m / min. Therefore, the residence time in the preheating zone and the foaming zone was set to 8 minutes in total, and that in the cooling zone was set to 4 minutes. The gap between the upper and lower cooling rolls in the cooling zone was set to 8 mm.
[0104]
A continuous composite sheet having a width of 700 mm and a thickness of 8 mm was obtained at the outlet of the foaming machine.
[0105]
Reference example 2
As in Reference Example 1, (1) Preparation of modified polyolefin resin, (2) Preparation of foamable resin composition, (3) Preparation of polyolefin resin foamable sheet, (4) Preparation of foamable composite sheet, (5) A polyolefin resin foam sheet was obtained through each step of foaming.
[0106]
(6) Preparation of stretched polyolefin resin sheet
1) Preparation of extruded sheet
1 part by weight of benzophenone (photopolymerization initiator) is blended with 100 parts by weight of high-density polyethylene (trade name: HY540, manufactured by Mitsubishi Chemical Corporation, MI = 1.0, melting point 133 ° C., weight average molecular weight 300,000). The blend was melt-kneaded at a resin temperature of 200 ° C. with a 30 mm twin screw extruder, extruded into a sheet with a T-die, and cooled with a cooling roll to obtain an unstretched sheet having a thickness of 1.0 mm and a width of 400 mm. It was.
[0107]
2) Rolling / crosslinking
This unstretched sheet was roll-rolled at a rolling magnification of 10 times using a 6-inch roll (manufactured by Kodaira Seisakusho) set at a surface temperature of 100 ° C., and then the obtained rolled sheet was rolled with a roll of 2 m / min. The film was drawn out, passed through a heating furnace set at an atmospheric temperature of 85 ° C., taken up by a roll with a take-up speed of 4 m / min, rolled up to 4 times, and wound up. Next, the obtained sheet was subjected to a crosslinking treatment by irradiating with a high pressure mercury lamp from both sides for 5 seconds. Finally, the obtained sheet was subjected to relaxation treatment at 130 ° C. for 1 minute under no tension.
[0108]
The stretched sheet obtained through the above operation had a size of a width of 200 mm and a thickness of 0.40 mm. The total draw ratio of this sheet is about 20 times, and the linear expansion coefficient determined by measuring the distance between marked lines of about 150 mm at two levels of 20 ° C. and 80 ° C. is −1.5 × 10 ^-Five Met. The stretched sheet had a melting point [peak temperature in DSC (differential scanning calorimeter)] of 149 ° C. and a tensile elastic modulus of 12 GPa. The tensile modulus and linear expansion coefficient of the sample were both measured according to the tensile test method of JIS K 7113.
[0109]
3) Lamination and heat fusion
A sample having a width of 200 mm and a length of 200 mm was cut out from the previously obtained polyolefin-based resin foam sheet.
[0110]
A low-density polyethylene film (thickness 30 μm, manufactured by Mitsubishi Chemical Corporation, UF230) having the same dimensions as the sample and the above-mentioned stretched sheets having the same dimensions were alternately stacked four by four to obtain a film-sheet laminate. The above laminates were arranged on both sides of a core layer made of a foam sheet in which fiber molded sheets were laminated on both sides to obtain three types and nine layers of laminates. In a hand press molding machine, temperature 125 ° C., pressure 98 kPa (1 kgf / cm ² ) For 2 minutes, and then water-cooled with a water-cooled press (pressure 98 kPa) to obtain a composite sheet (10) having a thickness of 5 mm.
[0111]
Composite sheet evaluation test
The composite sheet obtained in the reference example was evaluated for the following items.
[0112]
-Apparent density:
When the apparent density was measured based on JIS K 6767, it was 0.15 g / cc.
[0113]
-Bubble shape (average aspect ratio):
The composite sheet was cut in the thickness direction (z direction), and an enlarged photograph of 15 times was taken while observing the central part of the cross section with an optical microscope. Dz and Dxy of all the bubbles shown in the photograph were measured with calipers, the aspect ratio was calculated for each bubble, and the number average of the aspect ratio for 100 bubbles was calculated to obtain the average aspect ratio. However, during measurement, bubbles with Dz (actual diameter) of 0.05 mm or less and bubbles with 10 mm or more were excluded.
[0114]
The aspect ratio of the composite sheet obtained in Reference Example 1 was 2.2.
[0115]
・ Flexural modulus
Based on JIS K 7203, it was measured at a test speed of 10 mm / min, and the flexural modulus was calculated to be 8.1 GPa.
[0116]
5% compressive strength
Based on JIS K 7220, when the compressive stress at 5% strain was measured when measured at a test speed of 10 mm / min, it was 0.95 MPa.
[0117]
Linear expansion coefficient
It was determined by measuring the distance between marked lines of about 150 mm at two levels of 20 ° C. and 80 ° C., −1.2 × 10 ^-Five / ° C.
[0118]
Cutting process
When the obtained composite sheet was arbitrarily cut with a saddle-type universal band saw board (L-type manufactured by Laxou), no fine powder, dust or the like was generated.
[0119]
【The invention's effect】
The slope embedding method according to the present invention uses a synthetic resin foam as the remaining formwork, thus reducing the weight of the formwork and providing a slope embedding method that is easy to transport and has good workability. can do.
[0120]
When a remaining mold form containing spindle-shaped bubbles having a major axis in the thickness direction is used, the mold form is lightweight but excellent in rigidity in the compression and bending directions and does not require reinforcement by ribs or the like.
[0121]
Since bubble-containing lightweight concrete is lighter than soil and normal concrete, it is easy to fill and work, especially in mountainous areas. In addition, since the load imposed on the remaining mold is small, it is advantageous in terms of durability of the mold.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view showing a state in which embankment is applied to a slope of a natural ground.
FIG. 2 is a perspective view showing a state in which a remaining formwork is arranged across adjacent support piles.
FIG. 3 is a cross-sectional view of a remaining mold.
4 (a) is a perspective view of a foam sheet, and FIG. 4 (b) is a partially enlarged view of a cross section parallel to the z direction in FIG. 4 (a).
[Explanation of symbols]
(1): H steel (support pile)
(1a): Groove of H steel
(2): Slope
(3): Ground
(4): Residual formwork
(5): Core layer
(6): Stretched sheet
(7): Weather-resistant film
(8): Surface layer

Claims (3)

A plurality of support piles having groove portions are erected on the ground at predetermined intervals along the slope, and a plurality of residual molds made of synthetic resin foam are arranged over adjacent support piles, and both end portions thereof are groove portions. A slope embedding method characterized in that the same formwork is held by a support pile and soil or concrete is placed in the space between the slope and the remaining formwork. The slope embedding method according to claim 1, wherein the bubbles in the remaining mold are of a spindle shape having a major axis in the thickness direction. The slope embedding method according to claim 1 or 2, wherein the concrete is a lightweight concrete containing bubbles.

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