JP2832311B2 - Civil engineering method using foamable resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention relates to the construction of a mountain in a park or civil engineering work such as filling a hole after a road construction work, by foaming a foamable resin into a required shape on the site ground to form a foam. The present invention relates to civil engineering work using a foamable resin to facilitate the construction.

[Prior art]

Attempts have been made in the past to make use of the lightweight properties of the foamable resin to fill in depressions or to make them part of artificial ground. For example, a foamable resin is molded into a foam block having a predetermined shape at a factory, the foam block is piled up on an original ground to be embanked, and a concrete floor plate, a wall surface protecting material and the like are stretched on a surface layer to finish. Further, a reinforcing material such as a reinforcing bar is arranged inside to improve the structural strength. Here, when the ground is formed by stacking the foam blocks, a gap easily occurs between the foam blocks. Therefore, Japanese Utility Model Application Laid-Open No. 63-81941, Japanese Utility Model Application Laid-Open No. 63-81942, and the like, introduce a method of forming irregularities on the surface of a foam block and engaging the irregularities in order to eliminate the deviation. I have. Further, Japanese Patent Application Laid-Open No. 47-19617 discloses that an unfoamed resin such as urethane, vinyl chloride, and styrene is sprayed on a depression or a roadbed, and then a foaming reaction is performed to fill the depression or the like. I have.

[Problems to be solved by the invention]

However, the method of transporting the foamed block after foaming at the factory to the site and stacking the foamed block in a predetermined shape takes time and effort to transport and handle. For example, a large block of about 2 × 1 × 0.5 m is used as this type of block, but such a large block requires labor for transportation despite its light weight. In addition, the transportation is substantially as if carrying air, and there is much waste. Moreover, as the size of the block becomes larger, a gap is more likely to be formed between the original ground on which the work such as embankment is to be performed and the spread block, so that it is necessary to previously form the original ground. . On the other hand, JP-A-47-1961 in which a foamable resin is foamed on site
Such a problem is solved by the method described in Japanese Patent Application Laid-Open No. 7-74. However, there is no specific teaching in the publication regarding how to expand the expandable resin. By the way, simply foaming a resin often does not have a required contour on a foamed surface after foaming due to uneven foaming or the like. Further, when foaming is performed at the free interface, the foaming surface strength is not sufficient, and dents and the like easily occur when a stepping pressure is applied. Accordingly, an object of the present invention is to form a foam having a required contour and strength that can function sufficiently as a ground constituent material on a site ground without wasting energy.

[Means for Solving the Problems]

In order to achieve this object, the present invention relates to a civil engineering method using a foaming resin foamed by a heated gas, in which a circular hole having a predetermined depth is provided in the site ground, and a perforated plate is provided at the bottom of the circular hole. A gas can be ejected from the upper surface of the perforated plate, and a required amount of foamable resin material beads are charged into the upper surface of the perforated plate, and a number of small holes for venting gas are provided inside the circular hole in the above state. To form a closed space by covering the double-structured formwork, and to heat-foam the raw material beads while forcibly circulating a heating gas such as water vapor in the closed space, and expand the foam on the site ground in the formwork It is characterized in that the body is formed in a compressed state.

[Action]

In such a means, since a heating gas such as steam for heating and foaming the raw material beads is circulated in the mold and reused, there is no waste of energy. In addition, since the heated gas circulates through the mold to uniformly heat the raw material beads, the raw material beads are uniformly foamed, and the expanded foam is formed in a compressed state in the mold. And strength. In addition, it is preferable to compact the surface of the foam formed on the site ground using topsoil. As the foamable resin used in the present invention, various resins such as styrene resin, phenol resin, urea resin and urethane resin are commercially available. The foaming temperature of the foamable resin is appropriately determined depending on the type of the resin, but is usually 70 to 20
At about 0 ° C., a sufficient foaming reaction can proceed.

【Example】

Hereinafter, an embodiment of the present invention applied to a civil engineering work for constructing a mountain in a park will be specifically described with reference to the accompanying drawings. FIG. 1 shows an apparatus used in the present embodiment, a formwork 1 covering the site ground for the construction of a mountain, a perforated plate 2 installed on the site ground in the formwork 1, and a heating gas below the perforated plate 2 as a heated gas. A discharge pipe 3 for discharging water vapor, a supply hose 4 connected to the discharge pipe 3 for supplying water vapor, a pressure pump 6 connected to the supply hose 4 via a pressure regulating valve 5, and a supply of water vapor to the pressure pump 6 The boiler 7 mainly includes a recovery hose 8 that recovers steam from the mold 1 side and circulates the boiler 7. Therefore, first, a flat circular hole 9 with a predetermined depth at the bottom 9a is dug in the site ground for constructing the hill, and a discharge pipe 3 bent in an L-shape is buried therearound, and one end thereof is placed on the surface around the circular hole 9. The other end is made to face near the bottom 9a of the circular hole 9. Then, the perforated plate 2 covering substantially the entire area of the circular hole 9 is placed on the bottom 9 a of the circular hole 9 via the spar 10 so as to be located above the other end of the discharge pipe 3. Then, sand or the like is laid on the perforated plate 2 to form a fine-grained layer 11, and raw material beads of foamable resin are placed in the circular holes 9 above the fine-grained layer 11.
After the required amount of 12 is sprayed and spread, the formwork 1 is installed so as to cover the circular hole 9. As the mold 1, a water vapor recovery space 1e was formed between an inner frame 1b having a large number of small holes 1a for releasing steam and an outer frame 1d having a connection port 1c of the recovery hose 8. A hemispherical member is used, and its flange portion 1f is fixed to the ground around the circular hole 9 by an appropriate means such as stakeout. Then, the collection hose 8 is connected to the connection port 1c, and the supply hose 4 is connected to one end of the discharge pipe 3 to complete the preparation. After the completion of the preparation, the steam S generated by the boiler 7 is pressurized by the pressurizing pump 6 and adjusted to a predetermined pressure by the pressure adjusting valve 5. Discharge into the lower space. And the perforated plate 2, the fine-grained layer 11
Steam S, which has passed through and heated the raw material beads 12,
Is sucked from the small hole 1a of the inner frame 1b into the collection space 1e, circulated through the collection hose 8 to the boiler 7, and reused. Here, the input amount of the raw material beads 12 was set to 48 kg with the internal volume of the construction site covered with the form 1 being 16 m3. In addition, as the raw material beads 12, styrene resin beads having an average particle diameter of 0.9 mm were used. In the resin beads, the foaming reaction changes as shown in FIG. 2 depending on the relationship between temperature and time,
When the foaming is stopped, the foam expands to a foam having an expansion ratio of about 30 to 45 times, and the density of the foam becomes about 0.015 g / cm ³ . The temperature of the steam S discharged as the heating gas is 10
The temperature was 0 ° C., which was discharged at a flow rate of 2 m ³ per minute for 15 minutes. Under these conditions, the raw material beads 12
In the process of passing through 11, the entirety was uniformly heated by the finely dispersed water vapor S, and as the foaming progressed, was uniformly heated by the water vapor S circulating in the entire space in the mold 1 to uniformly foam. In the later stage of foaming, the foaming volume was regulated by the mold frame 1 to receive a compressive load, and a densely packed compressed body 13 was formed in the mold frame 1 without any gap. FIG. 3 shows a foam 13 obtained by removing the mold 1;
It has a predetermined contour along the formwork and its lower part 13a
Is located in the circular hole 9 so as not to move in the lateral direction. The foam 13 thus formed had an expansion ratio of about 35 times, a density of about 30 kg / m ³ and a dense surface. Here, FIG. 4 is a graph showing the results of an experiment in which the relationship between the density of the foam formed under various conditions and the compressive stress was determined.
It is a value obtained by measuring a compressive stress value when a compressive strain of 4% is applied to a 50 mm test piece. As apparent from FIG. 4, the strength of the foam increases as the density increases, and at a density of 30 kg / m ³ , the strength increases by 1.3%.
A compressive strength of about kg / cm ² is obtained. This compressive strength is that the stress generated under the pavement under the normal road load is 0.
Considering that it is 5 kg / cm ² or less, it indicates that the ground having sufficient treading strength has been obtained. In addition, since the compression density of 0.5 kg / cm ² or more can be obtained even when the foam density is 20 kg / m ^3, it is advantageous to reduce the foam density as much as possible when considering raw material consumption and weight reduction. .

【The invention's effect】

As described above, according to the present invention, since the heating gas such as steam for heating and foaming the raw material beads is circulated in the mold and reused, there is no waste of energy. Also, since the heated gas circulates through the mold to uniformly heat the raw material beads, the raw material beads are uniformly foamed, and thus formed in a compressed state in the foamed foam mold,
It has the required contour and strength and can function sufficiently as a ground component.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of the present invention, and is a side view showing a site ground as a cross section together with the device configuration. FIG. FIG. 3 is a cross-sectional view of the foam formed according to one embodiment, and FIG. 4 is a graph showing the relationship between the density of the foam and the compressive stress. 1 ... form, 1a ... small hole, 1b ... inner frame, 1c ... connection port, 1d ... outer frame, 1e ... collection space, 1f ... flange, 2 ... perforated plate, 3 ... ... Discharge pipe, 4 ... Supply hose, 5 ... Pressure regulating valve, 6 ... Pressure pump, 7 ... Boiler, 8 ... Recovery hose, 9 ... Circular hole, 9a ... Bottom, 10 ... Girder , 11 ... fine grain layer, 12 ... raw material beads, 13 ... foam, 13a ... lower part.

Claims (1)

(57) [Claims] 1. A civil engineering method using a foaming resin foamed by a heated gas, wherein a circular hole having a predetermined depth is provided in a site ground, and a perforated plate is provided at the bottom of the circular hole. In addition to allowing gas to be ejected from the upper surface, a required amount of foamable resin raw material beads are charged into the upper surface of the perforated plate, and the circular hole in the above state has a double structure having a number of small holes for venting gas inside. A closed space is created by covering the formwork, and the raw material beads are heated and foamed while forcibly circulating a heating gas such as water vapor in the closed space, and the foam is formed in a compressed state on the ground in the formwork. A civil engineering method using a foamable resin.