JP3660177B2 - Construction method of lightweight embankment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightweight embankment structure by in-situ foaming of polyurethane foam and a construction method thereof.
[0002]
[Prior art]
In recent years, rigid polyurethane foam or polystyrene foam has been used as a lightweight embankment material for soft ground, steep slopes, and structures.
(1). The method of forming embankment using rigid polyurethane foam is to transport the stock solution for making rigid urethane foam to the embankment site and inject or spray the stock solution to the embankment location with a rigid urethane foaming device to produce rigid urethane foam. It is done by damaging.
(2). The method of forming embankment using polystyrene foam is carried out by transporting a large number of polystyrene foam blocks produced in advance to the embankment site and laminating the blocks at the embankment site.
However, in the method (1), the height of the rigid polyurethane foam that can be produced at one time by injection or spraying is limited, and an exothermic reaction is involved in the production of the rigid polyurethane foam. Since the rigid polyurethane foam is cured and cooled to some extent, the second injection or spraying is performed, so that the construction period becomes long.
In the method of (2), Japanese Patent Application Laid-Open No. 1-66316 describes embankments that ensure the integrity of lightweight blocks, but the height, width, and depth of each block are accurate as shown in the design drawings. And if the surface is not smooth, it seems that it is difficult to form a solid embankment.
[0003]
Production of blocks made of polystyrene foam is generally performed in factories for equipment reasons, and the dimensions of each block can be processed almost as per the design drawing, and it is possible to construct an embankment without wobble. . However, since it is lightweight, it is inevitable that the ratio of transportation cost to price will increase.
[0004]
In addition, it is conceivable to reduce transportation costs by preparing blocks using a hard urethane foam preparation stock solution generally used as a material for heat insulating materials such as buildings, and urethane foaming machines that are easy to transport. When foaming hard urethane in the field, it is difficult to smooth all six surfaces of the block and make the dimensions of each block the same because it is difficult to control the ambient temperature. There was a problem that there was.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned problems, and provides a method for constructing a lightweight embankment that can reduce the construction period and can be integrated even when a block with various dimensions and no smoothness is used. is there.
[0006]
[Means for solving problems]
The construction method of the lightweight embankment of the present invention is a construction method of a lightweight embankment using a large number of blocks made of rigid urethane foam and a stock solution for producing rigid urethane foam, and the stock solution for producing rigid urethane foam mainly stacks blocks. Foam adhesive layer forming stock solution that adheres the upper and lower parts of the block, and a foam gap filling stock solution that foams and fills the gap formed between the block and the ground or between the block and the formwork. Before the stock solution is cured by injecting or spraying the adhesive layer forming stock solution, a large number of blocks are laid, and the lower part of the block is bonded and fixed by curing of the stock solution, and the foam gap filling stock solution is fixed to the block and the ground with the lower part fixed. Inject or spray into the gap formed between the block and the mold, and fix the side of the block by curing the stock solution, As next block laying position the top of the fixed block, and is characterized in that the repeating bonded and aspects of bonded and blocking a lower portion of the same block.
[0007]
Also, as the first layer process, a foaming gap filling stock solution is injected or sprayed on the ground to form a leveling layer by foaming and curing, and a foaming adhesive layer forming stock solution is injected or sprayed onto the leveling layer. Before the stock solution hardens, a number of blocks of the first layer are laid, and the lower part of the block is bonded and fixed by hardening of the stock solution, and the gap formed between the block to which the lower part is fixed and the ground or the block and the formwork If necessary, the foam gap filling stock solution is injected or sprayed to a position covering the upper part of the block, and the side surface of the block is bonded and fixed by curing the stock solution. Before the stock solution is cured by injecting or spraying a foam adhesive layer forming stock solution onto the block, a number of blocks in the second layer are laid, and the lower portion of the block is bonded and fixed by curing the stock solution, and the lower portion is secured. The foam gap filling stock solution is injected or sprayed into the gap formed between the block and the ground or the block and the formwork as needed to cover the top of the block, and the side of the block is bonded and fixed by curing the stock solution Then, the same process as the second layer is repeated, and a block made of rigid urethane foam is embedded in the rigid urethane foam to a desired height.
[0008]
In addition, the foamed adhesive layer forming stock solution is characterized in that it has a slower reactivity than the foaming gap filling stock solution.
[0009]
In the present invention, a gap is provided between the blocks laid at substantially the same height to form a strong embankment, and the side surfaces of the blocks are bonded and fixed, and a gap filling operation between the block and the ground or the block and the formwork is performed. It is preferable to fill the gap in parallel. The gap filling between the blocks can be either a foamed adhesive layer forming stock solution or a foaming gap filling stock solution, but the use of the foaming gap filling stock solution described below is preferred in order to speed up the work.
[0010]
Moreover, when forming a leveling layer on the ground, a drainage sheet can be laid between the ground and the leveling layer. In particular, when the ground is an inclined ground, it is preferable to provide a drainage sheet in order to drain groundwater that springs up from the mountain.
The drainage sheet is not particularly limited as long as it can drain, but a felt-like nonwoven fabric, a knitted fabric, a woven fabric, a double raschel or a sheet having a mesh-structured drainage pipe can be used.
[0011]
The stock solution for producing rigid urethane foam used in the present invention is used for the production of blocks, the formation of foamed adhesive layers, the formation of leveling layers, and the filling of gaps. It may be a thing, and consists of a polyol component and a polyisocyanate component. A rigid urethane foam is produced by mixing the two. A large number of blocks are firmly bonded and integrated by the self-adhesiveness of a rigid urethane foam produced by injection or the like afterwards or later.
[0012]
The foamed adhesive layer forming stock solution and the foam gap filling stock solution that are the stock solutions for producing rigid urethane foam may be the same, but the reactivity of the foamed adhesive layer forming stock solution is not limited to the above foaming in order to improve workability. It is preferably slower than the reactivity of the gap filling stock solution. That is, in order to improve the working speed, especially the formation of the leveling layer and the filling of the gap between the block and the ground, the block and the mold form, the working time is shortened by using a reactive solution, and foam bonding is performed. In forming the layer, it is preferable to use a stock solution having a low reactivity in order to secure a working time for adhesion between the lower part and the upper part of the block.
[0013]
The reactivity of the stock solution for producing rigid urethane foam can be easily performed by changing the amount of addition of a catalyst or the like. For example, two types of stock solutions with different reactivities may be prepared at the factory and transported to the site. A slow reacting stock solution is prepared at the factory and transported to the site, and the reaction is increased by increasing the amount of catalyst. It is also possible to produce a stock solution with high properties.
The reactivity of the foam gap filling stock solution is adjusted according to the situation at the site, but the rise time is usually preferably 15 to 20 seconds.
Although the reactivity of the foamed adhesive layer forming stock solution is also adjusted according to the situation at the site, a rise time of 120 to 180 seconds is preferable.
[0014]
The above-mentioned stock solution is transported in a drum can etc., pumped up to a rigid urethane foaming machine, etc., mixed and discharged, mixed with a block, formed a leveling layer, adhesively filled each gap, the top of the block and another block on it Used for bonding the lower part. In addition, since the foamed adhesive layer forming stock solution has low reactivity, it has a sufficient stirring time, and even if a foaming machine is not used, a polyol component and an isocyanate component are added to a plastic bag, etc., and then the two components are shaken. Can be mixed and stirred.
[0015]
The blocks used in the present invention can be made at and near the embankment site to reduce transportation costs. Also, depending on the situation of rain at the site, work can be carried out according to the work process determined by making blocks in another limited and narrow place even in rainy weather.
[0016]
In addition, it is preferable that the formwork in the case of producing a block on site is simple and light in weight so that it can be easily transported. In the field, it is difficult to keep the foaming ratio constant because it is difficult to accurately control the ambient temperature and the temperature of the stock solution. For this reason, if the mold is a sealed mold, the structure itself becomes complicated and excessive foaming pressure is applied to the mold, which may damage the mold if it is not a rigid mold, and as a result, the mold becomes heavy. An open top form with a simple structure and light weight is preferable. An example of a mold for making a block is shown in FIG.
However, the block obtained by using the mold with the upper part opened is not smooth as shown in FIG. The block size is not particularly limited, but is preferably 0.4 to 1.0 m in order to maintain the quality of the depth, width and height.
The present invention is characterized in that it is possible to construct an embankment with an integral rigid urethane foam even if the block dimensions are not accurate.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of an embankment structure obtained by the method of constructing a lightweight embankment of the present invention on a steep slope. FIG. 2 shows an example of the embankment structure obtained by the light embankment construction method of the present invention on a substantially flat soft ground or the like. Note that the mold 8 'is necessary for forming a bank with hard urethane foam, and is disassembled after the bank is formed.
FIG. 3 is an explanatory diagram of the construction method of the lightweight embankment of the present invention. In FIG.
(A) Laying the sheet 2 with a mesh-structured drainage pipe on the ground 12;
(B) Forming the leveling layer 3 by injecting or spraying the foam gap filling stock solution,
(C) Injecting or spraying a foamed adhesive layer forming stock solution on the leveling layer 3,
(D) Before the undiluted solution is cured, the block 5 prepared in advance using a mold for preparing a block near the site is laid. At this time, the block sinks into the foamed adhesive layer 4 due to its own weight or the like, and the lower part thereof is fixed on the leveling layer by curing of the stock solution.
(E) After the leveling layer and the lower part of the block are integrated via the foamed adhesive layer, the gap between the lower fixed block and the block, and the block and the mold B (in FIG. 3, the mold B is a retaining wall) 8 or a foaming gap filling stock solution is injected or sprayed into the gap created between the ground and the ground. In the present embodiment, the foam gap filling stock solution is injected or sprayed to a position covering the top of the block to form the foam gap filling layer 6 covering the top of the block.
(F) A foamed adhesive layer forming stock solution is again injected or sprayed on the foam gap filling layer or on the block, and the following (d) to (f) are repeatedly performed to construct a lightweight embankment.
The civil engineering structure is provided with the earth and sand 7 on the lightweight embankment formed as described above.
[0018]
【The invention's effect】
As described above, according to the construction method of the lightweight embankment of the present invention, since the block made of rigid urethane foam is integrally bonded and fixed by the same rigid urethane foam, the embankment is stronger than those of different materials. A structure is obtained.
Also, by laying the block before the foamed adhesive layer is cured, the block sinks into the foamed adhesive layer, so that the lower part of the block is fixed more firmly, while the side of the block is also filled with a gap later By injecting or spraying the stock solution to cause foaming, it can be easily filled with rigid urethane foam regardless of whether the gap between the block and the ground or between the blocks is wide or narrow.
Furthermore, the construction period can be shortened as compared with a method of injecting or spraying hard urethane foam at all embankment locations.
Moreover, even when using non-smooth blocks with mixed dimensions produced at the embankment site to reduce transportation costs, the same reason as above, that is, the lower part of the block sinks into the adhesive layer, and the gap formed on the side of the block Since it can be filled regardless of whether it is wide or narrow, there is no influence on the unevenness of the block size and the embankment strength of the irregularities on the block surface.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an example of a banking structure obtained by the present invention.
FIG. 2 is an explanatory diagram of an example of a banking structure obtained by the present invention.
FIG. 3 is an explanatory diagram of a method for constructing a lightweight embankment according to the present invention.
FIG. 4 is an explanatory view of a mold for producing a block used in an embodiment of the present invention. In the state as shown in (a), a stock solution for producing rigid urethane foam is injected or sprayed to produce a block, and the block is removed as shown in (b).
FIG. 5 is a cross-sectional view of an example of a block manufactured in an embodiment of the present invention when cut in half.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lightweight embankment 1 'Lightweight embankment 2 Sheet | seat with built-in drain pipe of mesh structure 3 Leveling layer 4 Foam adhesion layer 5 Block 6 Foam gap filling layer 7 Earth and sand 8 Formwork B (retaining wall)
8 'Formwork B
11 Drainage pipe 12 Ground

Claims (3)

It is a construction method of a lightweight embankment using a large number of blocks made of rigid urethane foam and a stock solution for producing rigid urethane foam,
The stock solution for making rigid urethane foam is mainly a foam adhesive layer forming stock solution that adheres the upper and lower parts of the block when stacking the blocks, and a foam gap that mainly fills the gap between the block and the ground or between the block and the formwork. Consisting of a filling stock solution,
Before the stock solution is cured by injecting or spraying the foam adhesive layer forming stock solution to the block laying location, laying a large number of blocks, and adhesively fixing the lower part of the block by curing the stock solution,
Injecting or spraying the foam gap filling stock solution into the gap formed between the block and the ground or the block and the mold with the lower part fixed, and fixing the side surface of the block by curing the stock solution,
A method for constructing a lightweight embankment, characterized in that the upper part of a block with a fixed lower part and side faces is used as the next block laying place, and the same adhesive fixing of the lower part of the block and adhesive fixing of the side face of the block are repeated. It is a construction method of a lightweight embankment using a large number of blocks made of rigid urethane foam and a stock solution for producing rigid urethane foam,
The stock solution for making rigid urethane foam is mainly a foam adhesive layer forming stock solution that adheres the upper part of the block and the lower part of the block when the blocks are stacked, and a foam that mainly fills the gap between the block and the ground or between the block and the formwork. Consisting of gap filling stock solution,
As a first layer process, a foaming gap filling stock solution is injected or sprayed on the ground to form a leveling layer by foaming and curing, and a foamed adhesive layer forming stock solution is injected or sprayed onto the leveling layer to form the leveling layer. Before the stock solution hardens, lay many blocks of the first layer and fix the lower part of the block by curing the stock solution, and foam in the gap created between the block with the lower part and the ground or between the block and the formwork Injecting or spraying the gap filling stock solution to fix the side surface of the block by curing the stock solution,
As a process of the second layer, by injecting or spraying a foam adhesive layer forming stock solution on the first layer block and laying a number of blocks of the second layer before the stock solution is cured, by curing the stock solution The lower part of the block is bonded and fixed, and a foam gap filling stock solution or a foam adhesive layer forming stock solution is injected or sprayed into a gap formed between the block to which the lower part is fixed and the ground or the block and the mold, and the block is obtained by curing the stock solution. Adhering and fixing the sides of the
2. The method for constructing a lightweight embankment according to claim 1, wherein the same process as in the second layer is repeated, and a block made of rigid urethane foam is embedded in the rigid urethane foam to a desired height. The method for constructing a lightweight embankment according to claim 1 or 2, wherein the foamed adhesive layer forming stock solution is slower in reactivity than the foam gap filling stock solution.

Images