JP2772994B2 - Civil engineering method using foamable resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a civil engineering method for producing a resin foam having a uniform foaming state and compressive strength when foaming resin is foamed to a required shape on site to perform embankment, formation of artificial ground, road widening work, and the like.

[Prior art]

Attempts have been made in the past to make use of the lightweight properties of the foamed resin to fill in depressions or to make them a 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 protection material and the like are stretched on the surface layer to finish. Further, a reinforcing material such as a reinforcing bar is arranged inside to improve the structural strength. When the artificial ground is formed by stacking the foams in this way, a gap easily occurs between the foam blocks. Accordingly, Japanese Utility Model Laid-Open No. 63-81941, Japanese Utility Model 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. 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. In addition, as the size of the block becomes larger, it is necessary to prevent the formation of a gap between the block and the block that is laid flat by flattening the original ground on which the work such as embankment is to be performed. Further, Japanese Patent Application Laid-Open No. 47-19617 discloses that an unfoamed resin such as urethane, vinyl chloride, styrene or the like is sprayed on a depression or a roadbed, and then a foaming reaction is performed to fill the depression or the like. ing. However, the publication does not specifically teach how to foam the resin. However, simply foaming the resin often does not have the required contour on the resin body surface after foaming due to uneven foaming or the like. In addition, when foaming is performed at the free interface, the surface strength of the foam is not sufficient, and dents and the like easily occur when a tread pressure is applied.

[Problems to be solved by the invention]

The present inventors, while making use of the advantages of on-site construction, as a method of forming an artificial ground having the required strength, as a method of forming foam, spread beads of foamable resin on the original ground partitioned by a formwork,
A method for constructing artificial ground by foaming resin beads with heated gas was developed. Incidentally, when the ground is constructed by foaming the resin beads, uneven foaming of the resin beads tends to occur. As a result, defects such as generation of irregularities on the surface of the resin body after foaming and generation of internal cavities will occur. Such defects are:
It is presumed to be due to the fluctuation of the foaming atmosphere of the resin beads. Therefore, an object of the present invention is to form a resin foam ground having a uniform foam structure and compressive strength by uniformly bringing a heating gas into contact with the resin beads to foam the resin beads uniformly. And

[Means for Solving the Problems]

In order to achieve this object, the civil engineering method of the present invention arranges a plate made of a porous material or a plate in which a number of pores are perforated above the original ground to form the original ground and the plate. A chamber is formed between the plates, resin beads are sprayed on the plate, a mold is arranged above the beads via a space, and the heated gas supplied to the chamber is allowed to permeate the plate. And heating and foaming by contacting with the resin beads.

[Action]

The heating gas such as water vapor supplied to the chamber is supplied to the resin beads through a plate made of a porous material or a plate having a large number of pores. At this time, the heated gas supplied from the boiler or the like via the air supply pipe is released from the supply pressure in the chamber, and then flows toward the resin beads via the porous gaps or pores of the plate. Therefore, the heated gas contacts the resin beads with a uniform flow rate distribution over the entire surface of the plate body, and the resin beads are uniformly foamed over the entire surface. Therefore, local occurrence of the foaming reaction is suppressed, and a resin foam having a uniform foaming state can be obtained.

【Example】

Hereinafter, the present invention will be described in detail with reference to the drawings by using an embodiment applied to an embankment having an inclined surface. In this embodiment, a predetermined embankment is formed on the inclined surface 2 of the original ground 1 as shown in FIG. A gas permeable plate 4 is arranged above the lower ground 3, and a chamber 5 is formed between the lower ground 3 and the plate 4. The gas permeable plate 4 is made of, for example, ceramics sintered in a porous state,
Foam concrete, a metal plate having a large number of pores, and the like are used. The permeable plate 4 is supported by a pile 5 driven into the lower ground 3 and is maintained at a predetermined height from the lower ground 3. An appropriate amount of resin beads 7 are sprayed on the air-permeable plate 4 with an even thickness. Various types of resin beads 7 such as foamable styrene resin, urethane resin, and urea resin are known. For example, a styrene resin used in a wide range of fields as a material for a resin foam expands at an expansion ratio of about 35 to 45 times. Therefore, the form 8
Is placed. It is preferable that the inner volume of the mold 8 be slightly smaller than the volume obtained when the resin beads 7 are foamed in a free state. Thereby, in the final stage of the foaming of the resin beads, a restraining force, that is, pressure is applied by the mold frame 8, and the surface layer of the resin foam becomes dense. An air supply pipe 9 is opened in the chamber 5. This air supply pipe 9 is connected to a heated gas source such as a boiler 11 via an air supply pump 10. Next, a procedure for forming a ground with a resin foam using this apparatus will be described. A styrene resin having an average particle size of 0.9 mm was used as the resin beads. This resin starts a foaming reaction in relation to temperature and time as shown in FIG.
Expanded to about 30 to 45 times the foam, the density after foaming is about 0.01
It was 5 g / cm ³ . As the inclined surface 2, one having a cross section of 1 m × 1 m and a step of 80 cm was prepared. At a height of 10 cm from the lower ground 3 of the inclined surface 2, a porous ceramics plate 4 having a thickness of 5 cm was arranged. Then, an air supply pipe 9 having an inner diameter of 30 mm was opened in the chamber 5 formed between the lower ground 3 and the porous ceramic plate 4. In addition, the porous ceramics plate 4
It was supported by a pile 6 driven at a depth of centimeters. Then, resin beads 5 having a thickness of 23 mm were sprayed on the porous ceramic plate 4. In this state, steam at a temperature of 100 ° C. was supplied from the boiler 11 to the air supply pipe 9 at a flow rate of 0.1 m ³ per minute. After the water vapor once expanded in the chamber 5, it permeated through the porous ceramics plate 4 and contacted the resin beads 7 as a flow having a uniform flow rate distribution. When the steam injection was continued for 15 minutes, the resin beads 5 expanded to a height of 65 cm from the surface of the porous ceramic plate 4. The resin beads 5 continue to expand and attempt to expand, but the outer shell is restrained by the mold 8. For this reason, the force for expanding acts as a reaction force on the resin foam, and the surface of the resin foam becomes dense. Next, the mold 8 was removed, and the formed resin foam was taken out from the inclined surface 2 and cut in the vertical and horizontal directions to observe the internal foaming state. As a result, it was found that the foamed structure was substantially uniform in both directions. Also,
A test piece was cut out from this foam, and the compressive strength was measured.
It was in the range of 2.0 kg / cm ² . From this, it can be seen that the ground having a strength sufficiently larger than 0.5 kg / cm ^2, which is the average tread pressure applied when the vehicle is running, is obtained. A test in which a 100 kg moving load is repeatedly applied to this resin foam
After the lapse of time, the surface state of the resin foam was examined, and no defect such as depression was detected. On the other hand, when the water vapor was directly blown out to the resin beads 5 without providing the porous ceramic plate 4 and heating and foaming were performed, the obtained resin foam had an uneven foaming state and a compressive strength of 0.5 to 2.5. large was varied and kg / cm ^2. This is considered to be due to the fact that the flow rate of the supplied water vapor fluctuates in the gas blowing direction and that the resistance of the gas passage formed between the resin beads 7 varies. Due to the non-uniformity of the foaming state and the variation in the compressive strength, when a moving load was repeatedly applied to the obtained resin foam in the same manner, a locally depressed portion was detected. In the above embodiment, the embankment on the inclined surface 2 is described as an example. However, the present invention can be applied to embankment of a depression or expansion of a road width by the same method. In addition, by further providing a gas permeable plate on the formed resin foam, and heating and foaming the resin beads again on the gas permeable plate, the resin foam is stacked in multiple layers to form a deep depression. Embankment can also be performed on slopes with large steps or road side surfaces.

【The invention's effect】

As described above, in the present invention, when the resin beads are foamed on site to construct the ground, a heated gas such as water vapor is used to form a porous material plate or a large number of pores. The resin beads are supplied through the plate. As a result, the contact between the resin beads and the heated gas is made uniform, and the inside and outside of the foamed resin become almost uniformly foamed, so that the compressive strength does not locally decrease.
Thus, according to the present invention, it is possible to easily construct a ground having sufficient strength to withstand tread pressure.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment in which the present invention is applied to formation of an inclined surface, and FIG. 2 is a graph showing a foaming state in relation to temperature and time. DESCRIPTION OF SYMBOLS 1 ... Original ground, 2 ... Inclined surface 3 ... Lower ground, 4 ... Breathable plate 5 ... Chamber, 6 ... Pile 7 ... Resin beads, 8 ... Formwork 9 ... Air supply pipe , 10 …… Air supply pump 11 …… Boiler

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 17/18 E02D 3/00 E01C 3/00

Claims (1)

(57) [Claims] 1. A plate made of a porous material or a plate having a large number of pores is disposed above the original ground to form a chamber between the original ground and the plate. The resin beads are sprinkled on the plate body, a mold is arranged above the beads via a space, and the heating gas supplied to the chamber is transmitted through the plate body and brought into contact with the resin beads for heating. -Civil engineering method using foamed resin characterized by foaming.