JP2566422B2 - Lightweight embankment structure and construction method - Google Patents

Description

The present invention relates to a structure of an embankment having a block structure layer made of a lightweight block therein as a constituent element, and a method for constructing the embankment structure.

[Conventional technology]

Conventionally, as the structure of the embankment made for the purpose of site construction or embankment, the whole structure has been mainly composed of only sand or earth and sand. However, in these conventional embankment structures, the soil pressure that acts on them is high due to the high density of the sand, earth and sand, etc. that make them up. There was a case where a so-called slip that spreads toward one side occurred. Moreover, when constructing the embankment as backfilling for a retaining wall, for example, it was necessary to make the retaining wall large in cross section to support the large lateral pressure. As a means for reducing such a load, a banking structure using a lightweight material such as expanded polystyrene (styrofoam) has been proposed in recent years, and some construction examples have already been seen in Norway and the like.

This embankment structure has a block structure layer formed by laminating a large number of blocks made of expanded polystyrene, for example, and the weight of the embankment is reduced by partially replacing the conventional sand etc. with this block structure layer. Is intended.

[Problems to be solved by the invention]

By the way, in the above-mentioned conventional lightweight embankment structure, the weight of the embankment is reduced by using the lightweight foam, and the block structure layer can be constructed simply by stacking ready-made blocks, which is excellent in workability. However, there is no integrity between each block, or between the block structure layer and the lower ground, etc.Therefore, when a large top load is applied, it may cause settlement due to block displacement, The resistance against horizontal force was extremely weak, and there was a risk of deformation when these large external forces were applied.

The present invention has been made in view of the above circumstances, in a lightweight embankment formed by forming a lightweight block structure layer inside,
An object of the present invention is to provide a lightweight embankment structure that is not only lightweight and excellent in workability, but also that can secure the integrity of the entire embankment and exert a strong resistance to load and horizontal force, and a construction method thereof. It is a thing.

[Means for solving problems]

A first aspect of the invention is a lightweight embankment structure in which a structural layer of a block in which a large number of lightweight blocks are laminated is formed.
The block structure layer is integrally fixed by a polyurethane foam, and further, the block structure layer is integrally fixed by being entirely covered with the polyurethane foam.

A second invention is a method for constructing a lightweight embankment, which comprises a block structure layer in which a large number of lightweight blocks are laminated, and a coating layer made of a polyurethane foam that forms the outside of the block structure layer, The steps of stacking the lightweight blocks to assemble the desired block structure layer on the ground, the step of assembling the frame body on the outside of the assembled block structure layer along the design slope of the embankment, and the foaming in the formwork And a step of injecting a raw material material for polyurethane foam before curing so as to cover the entire block structure layer, and a step of removing the mold after foaming and curing of the raw material material, Further, the lightweight blocks are stacked and mounted on the ground to assemble the block structure layer, and between the lightweight blocks and the ground to be mounted on the ground,
In addition, it includes a material in which the raw material for polyurethane foam before foaming and curing is interposed between the respective lightweight blocks.

[Action]

The integral structure of the block structure layer increases the rigidity of the block structure layer and increases the deformation resistance of the embankment against external force. In addition, since foams such as polyurethane can be foamed and cured in the field, if the coating layer is formed in the field using a formwork, the coating layer can be efficiently integrated with the block structure layer to form a block. The structural layer can be constrained.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the lightweight embankment structure according to the first aspect of the present invention. The embankment 1 includes a block structure layer 3 formed by stacking a large number of lightweight blocks 2 and a coating layer 4 that covers the outside of the block structure layer 3. Code G
Is the ground.

The lightweight block 2 is made of expanded polystyrene (styrofoam), and the block structure layer 3 is formed by stacking the lightweight blocks 2 at a construction site. The covering layer 4 covers the outer surface of the block structure layer 3 and fills the embankment 1
Of the coating layer 4 in the present embodiment.
Is composed of sand or the like, which is a component of a conventional embankment. The light weight blocks 2 forming the block structure layer 3 or the light weight block 2 and the ground G directly placed on the ground G are fixed to each other by a polyurethane foam 5.

The embankment 1 having the above structure is constructed as follows. First, the ground G is laid evenly and the pooled water on the ground is removed, and then isocyanate and water are mixed with a polyurethane stirrer (hand mixer) to generate polyurethane before foaming and curing. The foam raw material (hereinafter abbreviated as “foam raw material”) 5a is spread on the ground G using a spraying machine or the like. Before the foam raw material 5a sprinkled on the ground G is foamed, the lightweight block 2 is sprinkled on it. By the way, foaming occurs in about 5 minutes. At this time, the foam raw material 5a is also attached to the side surfaces of the adjacent lightweight blocks 2. When the foam raw material 5a is foamed / cured to generate the polyurethane foam 5, the foamed material 5a is foamed / cured again on the upper surface of the lightweight block 2 placed on the ground G through the polyurethane foam 5. The foaming raw material 5a is sprinkled, and the light-weight block 2 constituting the second layer is placed thereon, and the foaming raw material 5a is placed.
Wait for foaming and curing. Of course, the foam raw material 5a is also attached to the side surfaces of the lightweight blocks 2 forming the second layer before mounting. After that, by repeating the above steps, the block structure layer 3 having a required height is formed. After the block structure layer 3 is formed, sand / soil or mortar / concrete or the like is placed and solidified on the block structure layer 3 to solidify it.
Should be formed. At this time, if the foaming material 5a before foaming / curing is adhered to the outer surface of the block structure layer 3 as well, the integration of the coating layer 4 and the block structure layer 3 can be promoted.

In the embankment 1 configured as described above, the block structure layer 3
Of course, it is possible to realize a significant weight reduction of the entire embankment 1 and prevent consolidation and settlement of the ground, and the light weight blocks 2 forming the block structure layer 3 are made of polyurethane foam between the light weight blocks 2 and the ground G. Since they are fixed to each other by the body 5, the rigidity of the whole embankment 1 is greatly increased as compared with the conventional structure in which lightweight blocks are simply stacked, and even when a large vertical load or horizontal load is applied to the embankment 1, The deformation due to these external forces becomes much smaller. Moreover, the polyurethane foam 5 fixes the light blocks 2 together, that is, integrates them. That is, even when the light weight block 2 is made of expanded polystyrene as in this embodiment, it does not contain an organic solvent that melts polystyrene like ordinary adhesives, but melts it. There is no damage. In addition, the adhesive usually dislikes water, and the adhesive performance tends to be greatly reduced when the water content is high, but the polyurethane foam 5 is made by the reaction of isocyanate and water (compound having active hydrogen). In this case, water does not become an inhibitory substance but becomes a factor that contributes to the adhesive action. Moreover, the foam raw material 5a before foaming / curing has a low viscosity, a large polarity, good "wetting" on the coated surface, and the polyurethane foam 5 produced and the ground G can be expected to be integrated. In addition, the reason why the accumulated water is removed before the foam raw material 5a is scattered on the ground G is to prevent the polyurethane foam 5 from becoming partially non-uniform.

FIG. 2 shows a second embodiment of the lightweight embankment structure according to the first invention. The same components as those of the first embodiment are designated by the same reference numerals to simplify the description.

In the second embodiment, as in the first embodiment, the embankment 1 has a block structure layer 3 formed by laminating a plurality of lightweight blocks 2 made of expanded polystyrene, and an outer side of the block structure layer 3. Although it is composed of a covering tank for covering, the covering layer 4 is composed of a polyurethane foam 5. Also, in the present embodiment,
The lightweight block 2 is not fixed to each other like the conventional one.

Next, a method for constructing the lightweight embankment according to the second invention will be described together with a method for constructing the lightweight embankment 1 according to the second embodiment of the first invention.

First, as shown in FIG. 3A, the block structure layer 3 is formed by stacking the lightweight blocks 2 on the ground G.
In this case, the lightweight block 2 is made of expanded polystyrene. This work is extremely easy and efficient because the lightweight blocks 2 are simply laid and laminated as in the conventional block structure layer construction method.

Subsequently, as shown in FIG. 2B, a metal foam (metal frame) 6 is set along the intended design slope F of the embankment 1.

Next, as shown in FIG. 3C, the foaming material 5a before foaming and curing is injected into the metal foam 6. afterwards,
Wait for this foam material 5a to foam and cure,
Meanwhile, water is sprinkled on the metal foam 6 from the outside. This is because a high reaction heat is generated when the foam raw material 5a foams, and this heat may adversely affect the block structure layer 3. Further, the metal foam is used as the mold in order to improve heat dissipation.

The foam raw material 5a is foamed and cured, and the same figure (d)
When the covering layer 4 is formed as the polyurethane foam 5 as described above, the metal foam 6 is disassembled to complete the construction of the target lightweight embankment 1 as shown in FIG.

According to the above method, the covering layer 4 can be integrated to enhance the rigidity of the covering layer 4 itself, and the covering layer 4 and the block structure layer 3 can be integrated to realize the block structure layer 3 The respective lightweight blocks 2 constituting the above are integrally fixed (constrained), whereby the rigidity of the entire embankment 1 can be greatly increased. Moreover, since the coating layer 4 is formed by molding polyurethane on the site using a mold, the integration with the block structure layer 3 described above is performed simultaneously with the formation of the coating layer 4, which is efficient. Furthermore, since polyurethane has a very small specific gravity and a low foaming pressure, the mold (metal foam 6) may have a rigidity lower than that of a mold for concrete, and the construction can be easily performed. . Further, since the coating layer 4 made of the polyurethane foam 5 can be expected to be integrated with the ground G by the adhesive action as described above, the embankment 1 has higher rigidity.

In addition, in the lightweight embankment structure 1 according to the second embodiment of the first aspect of the present invention, of course, it is possible to realize a significant weight reduction of the entire embankment by the block structure layer 3 and prevent consolidation and subsidence of the ground.
The block structure layer 3 composed of the lightweight blocks 2 is
Since the polyurethane foam 5 is integrally fixed to the covering layer 4 which is integrally configured by the polyurethane foam 5, the rigidity of the entire embankment 1 is significantly increased, and even when a large vertical load or horizontal load is applied to the embankment 1. Therefore, the lightweight block 2 is not displaced, and the deformation of the entire embankment 1 due to the external force is extremely small. In addition, since the coating layer 4 is made of the polyurethane foam 5, it is possible to perform the integral molding on site as described above, and it is possible to perform the extremely efficient construction.

Further, in the embankment 1 according to the second embodiment described above, the lightweight blocks 2 forming the block structure layer 3 are not fixed to each other. However, as in the embankment 1 according to the first embodiment, the lightweight blocks 2 are made of polyurethane. Needless to say, it may be fixed by the foam 5. In that case, in the step of assembling the block structure layer 3 described above, the step described in the first embodiment may be applied as it is. In this case, in addition to the integration of the coating layer 4, the integration of the coating layer 4 and the block structure layer 3, the integration of the block structure layer 3 itself, and the integration of the block structure layer 3 and the ground 3 Therefore, the rigidity of the embankment 1 can be further increased by their synergistic effect.

The embankment structure and the construction method thereof according to the present invention are
Of course, the present invention may be applied not only to the embankment of the form shown in the embodiment but also to the embankment for backfilling a retaining wall, for example.

〔The invention's effect〕

As described above, according to the lightweight embankment structure of the first invention, the block structure layers are integrated,
The block structure layer has a strong resistance to external force and can suppress the deformation of the embankment due to a large load or horizontal force. Moreover, by fixing the block structure layer with the polyurethane foam, even when the lightweight block constituting the block structure layer is made of expanded polystyrene, etc., it does not adversely affect them and the block structure layer In the case of fixing with a coating layer,
It is possible to integrally mold the coating layer that exhibits this fixing action on site. Further, according to the method of constructing a lightweight embankment according to the second aspect of the present invention, the block structure layer is fixed and integrated simultaneously with the formation of the covering layer, and a highly rigid lightweight embankment is constructed very easily and efficiently. be able to. In particular, since the embankment has a very large volume and has a simple cross-sectional shape in most cases, this method is extremely effective and can significantly shorten the construction period.

[Brief description of drawings]

FIG. 1 shows the first embodiment of the lightweight embankment structure of the first invention, and is an overall cross-sectional view of the embankment. FIG. 2 is the second embodiment of the first invention, which is the entire cross-section of the embankment. Drawings and Drawing 3 (a)-(e) explain the construction method of the lightweight embankment which is the 2nd invention, and are sectional views in each process of embankment, respectively. G ... Ground, F ... Slope, 1 ... Embankment, 2 ... Lightweight block, 3 ... Block structure layer, 4 ... Covering layer, 5a ... Raw material for polyurethane foam, 5 ... Polyurethane foam Body, 6 ... Metal foam.

Claims (4)

(57) [Claims] 1. A lightweight embankment structure having a block structure layer formed by laminating a large number of lightweight blocks therein, wherein the block structure layer is integrally fixed by a polyurethane foam. Construction. 2. The lightweight embankment structure according to claim 1, wherein the block structure layer is integrally fixed by being entirely covered with a polyurethane foam. 3. A method for constructing a lightweight embankment comprising a block structure layer in which a large number of lightweight blocks are laminated, and a coating layer made of a polyurethane foam that forms the outside of the block structure layer. The steps of stacking and building the desired block structure layers on the ground, assembling the formwork along the design slope of the embankment on the outside of the built up block structure layers, and before foaming and hardening in the formwork Lightweight embankment, comprising: a step of injecting the polyurethane foam raw material so as to cover the entire block structure layer; and a step of removing the mold after foaming and curing of the polyurethane foam raw material. How to build. 4. When the lightweight blocks are stacked and the block structure layer is assembled on the ground, before the foaming / curing is performed between the lightweight blocks placed on the ground and between the respective lightweight blocks. The method for constructing a lightweight embankment according to claim 3, wherein the raw material material for polyurethane foam is interposed.