JP3897107B2 - Structure and its construction method by bubble lightweight mixed earth method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure by a light-weight lightweight mixed earth method and its construction method, and in particular, a structure capable of effectively preventing the occurrence of cracks in a light-weight embankment formed from a light-weight mixed earth and its construction. Regarding the method.
[0002]
[Prior art]
The FOAMED CEMENT BANKINB-FCM method is known. A lightweight lightweight mixed soil is a fluid material that is a mixture of cement, raw material soil, and water in an appropriate ratio, and is blended with a certain amount of bubbles. Or between a wall panel and a natural ground, between a retaining wall and a retaining wall standing on the ground, or between a retaining wall and a natural ground. The foamed light-weight mixed soil is hardened to become a light-weight embankment, and a structure by a light-weight light-weight mixed earth construction method is constructed by pavement or the like on the light-weight embankment (for example, Patent Documents 1, 2, 3 etc.).
[0003]
In the case of a retaining wall, it may be flat like a normal retaining wall, or it may be an abutment 10 having a footing 11 that spreads laterally as in the case of making a bridge (see FIG. 8). In the example shown in FIG. 8, the bridge 1 is attached to the left side of the abutment 10, and the natural mountain embankment 2 is on the left side. The abutment 10 is fixed to the ground 3 so that the footing part rides on the foundation pile 4 built in the ground 3. The light-weight light-mixed soil is placed in the space S between the abutment 10 and the natural ground embankment 2, and the light-weight embankment 5 is formed by hardening the foamed light-weight mixed soil. A pavement 6 or the like is constructed on the formed lightweight embankment 5. The light-weight mixed soil of foam is fluid and generates a side pressure immediately after placing, but the side pressure is reduced because it is self-supporting after curing. Therefore, structures such as a formwork, a wall panel, or a retaining wall can be simplified to some extent (for example, see Non-Patent Document 1).
[0004]
For example, when using the abutment 10 erected on the ground 3 as a retaining wall in the structure using the lightweight foam mixed earth method, fluid pressure is applied to the abutment 10 without being self-supported until the foamed lightweight mixed soil is cured. In addition, a downward load is applied when the embankment 5 is placed on the footing 11 of the abutment 10. Accordingly, unevenness or the like occurs on the road surface, and a crack K may occur between the embankment 2 and the abutment 10 as shown in FIG. In order to avoid this, as shown in FIG. 9, it has been reported that it is effective to arrange a resin sheet 8 such as a foamed polystyrene sheet as a joint material on the outside of the footing (Non-Patent Document 2). In FIG. 9, reference numeral 7 denotes a tread plate that is arranged as necessary.
[Patent Document 1]
JP-A-10-131191 [Patent Document 2]
JP 2000-178085 A [Patent Document 3]
JP 2002-188148 A [Non-Patent Document 1]
"FCB Construction Method Using Bubble-mixed Lightweight Soil" Brochure-Japan Road Research Institute Earth Work Test Laboratory, P5
[Non-Patent Document 2]
“Draft guideline on design and construction of lightweight embankment method using bubble-mixed lightweight soil”, March 1996, Japan Road Research Institute, Earthwork Testing Laboratory, P.M. 35-38
[0005]
[Problems to be solved by the invention]
In the structure shown in FIG. 8, as shown in FIG. 9, by arranging the resin sheet 8 as a joint material, that it to effectively suppress cracks lightweight fill 5 is a bubble lightweight mixed soil occurs Can do. However, one footing 11 is still loaded by the lightweight embankment 5a placed on it, and for some reason (for example, an unexpectedly large vertical or horizontal force acts on the abutment due to an earthquake or the like. The balance may be lost, and the abutment 10 may behave to fall to the mountain side. It is not easy to absorb all such abutment behavior with joint materials, and there is a risk of causing cracks in lightweight embankments.
[0006]
Even when the retaining wall is not an abutment with a footing, but a flat plate like a retaining wall, it usually has a base with some width, and the action of the lightweight embankment on that part It is also predicted that similar behavior will occur.
Further, in any case, when the cellular lightweight mixed soil is in a fluid state, the side pressure directly acts on the inner surface of the retaining wall, so it is necessary to carefully perform the concrete foundation work of the retaining wall.
[0007]
The present invention has been made in view of the circumstances as described above, and even when an unexpected force greater than the design value acts on the retaining wall, it suppresses the occurrence of a behavior that falls on the retaining wall, thereby An object of the present invention is to provide a structure using a light-weight and lightweight mixed earth construction method capable of preventing the occurrence of cracks in road surface unevenness and light-weight embankment which is a light-weight mixed soil. Another object of the present invention is to provide a structure using a light-weight lightweight mixed earth method that can reduce the lateral pressure acting on the retaining wall when the light-weight light-mixed soil is uncured and a construction method thereof. .
[0008]
[Means for Solving the Problems]
The structure according to the present invention is a structure based on a lightweight lightweight mixed earth method having at least a retaining wall erected on the ground and an embankment of cellular lightweight mixed soil. Between these, a layer made of a resin foam is formed in close contact with the inner surface of the retaining wall.
[0009]
In the above structure, on the inner surface side of the retaining wall, a layer made of a resin foam that is light and has a specific gravity smaller than that of the cured cellular lightweight mixed soil is closely located. It is on the base. Therefore, there is no great difference in the force acting downward on the outer surface side and the inner surface side of the retaining wall, and the behavior that the retaining wall falls to the mountain side is suppressed. Lightweight embankment with cellular lightweight mixed soil will face the inner surface of the retaining wall through the resin foam layer, but the retaining wall itself is less likely to fall to the mountain side, and the inner surface side of the retaining wall Since the resin foam layer located in close contact with the resin can also function as a joint material made of a conventional foamed resin sheet, it is possible to prevent cracking of the light weight embankment. Moreover, since the resin foam layer also functions to reduce the side pressure acting on the retaining wall when the cellular lightweight mixed soil is uncured, the foundation construction of the retaining wall can be simplified.
[0010]
In the present invention, the retaining wall may be a flat plate like an ordinary retaining wall, but the present invention functions particularly effectively when it is an abutment having a wide footing. That is, in the case of an abutment equipped with a footing, if the embankment material is placed only on one footing, the left and right balance is lost and a large overturning moment acts. According to the present invention, a lightweight resin foam layer is placed on at least the footing. In comparison, the overturning moment is reduced, and the left and right balance is stabilized. Therefore, compared with the case of the structure by the bubble lightweight mixed earth method using the conventional abutment, it can prevent effectively that a crack is produced in a lightweight embankment.
[0011]
In the present invention, the type of the resin foam used to form the resin foam layer is not particularly limited. Examples thereof include polystyrene resin foam, polyethylene resin foam, polypropylene resin foam, and polyester. Such as a resin foam. Polystyrene resin foams are particularly preferred for reasons of buffering properties, moldability, water resistance and economy. From the viewpoint of ease of construction, it is effective to stack block-shaped resin foams in multiple stages to form a resin foam layer. In the present invention, for example, a concrete retaining wall can be made later by using the resin foam layer as a mold. Also in this case, it is effective to stack the block-like resin foams in multiple stages to form a resin foam layer. In addition, what is necessary is just to use the thing currently used with this kind of construction method as a bubble lightweight mixed soil as it is.
[0012]
In the present invention, a resin foam layer is formed along the inner surface of the retaining wall, and thereafter, a lightweight foamed mixed soil is cast on site. When the foamed light-weight mixed soil is hardened, it becomes about 80 ° C. to 100 ° C. due to the reaction heat of the concrete, and the internal moisture becomes water vapor. Due to the heat and water vapor, when the resin foam layer is a polystyrene resin foam, in particular, the resin on the surface is hardened, thirdarily foamed, contracted, or hollowed out, and heat is trapped there. It may happen that the resin melts above 100 ° C. and cracks occur.
[0013]
In order to avoid such a situation, in the structure according to the present invention, a foamed resin sheet that functions as a heat insulating layer is preferably disposed between the layer made of the resin foam and the lightweight embankment. The foamed resin sheet may be a foamed resin sheet that has heat insulating properties and moderate buffering properties and is heat resistant to reaction heat, such as polyethylene resin foam, polypropylene resin foam, PET foam, and rigid urethane foam. Body, phenolic resin foam, epoxy resin foam and the like. Such a foamed resin sheet is affixed to the side surface of the resin foam layer by an appropriate means.
[0014]
In the present invention, when the resin foam layer is composed of resin foam blocks stacked in multiple stages, buoyancy occurs due to the uncured cellular lightweight lightweight soil that is placed, and there is a risk that the stacked blocks may be misaligned or collapsed. is there. In order to avoid this, in the structure according to the present invention, it is preferable that a horizontal layer having a required thickness (for example, about 100 mm to 150 mm) is placed at an appropriate position in the vertical direction of the stacked resin foam blocks (for example, at intervals of about 1 m). A concrete layer spreading in the direction is formed as a weight. Since the lifting of the block is suppressed by the weight of the formed concrete layer, stable construction can be performed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on embodiments with reference to the drawings. 1 to 4 illustrate a structure according to the present invention using a light-weight and lightweight mixed earth method together with its construction procedure. In the structure of this embodiment, the abutment 10 is used as the retaining wall, as in the case shown in FIGS. 8 and 9, and the bridge 1 is attached to the left side of the abutment 10 in the figure, and the left side becomes the natural ground embankment 2. ing. The abutment 10 has a footing 11 having a required width (for example, about 2000 mm) at the bottom, and is fixed to the ground 3 so that the footing rides on the foundation pile 4 built in the ground 3. Yes.
[0016]
After making the abutment 10 as a retaining wall in this way, resin foams 20a such as block-like polystyrene-based resin foams (EPS) are piled up to a predetermined height on the footing 11 on the mountain side (see FIG. 1). Concrete is cast on the stacked resin foam 20a to a thickness of about 100 mm to 150 mm and waits for curing (FIG. 2). The concrete layer 21 functions as a weight with respect to the lower resin foam 20a, and when the foam lightweight mixed soil is cast, the block-shaped resin foam 20a is formed by buoyancy generated by the uncured cellular lightweight mixed soil. Prevent floating.
[0017]
After the cast concrete has hardened, the block-shaped resin foam 20b is again piled up to a predetermined height on the concrete layer 21, as shown in FIG. If necessary, the tread plate 7 is mounted thereon. The weight of the tread plate 7 prevents the block-shaped resin foam 20b from floating. By the stacked block-like resin foams 20 a and 20 b, the “layer made of resin foam” according to the present invention is formed in close contact with the inner surface of the abutment 10. In the figure, only one layer is shown as the concrete layer 21, but two or more concrete layers 21 are formed according to the height of the abutment 10. In that case, it is desirable to form the concrete layer 21 for every 1 m in height of the block-shaped resin foam piled up.
[0018]
For example, a heat insulating sheet 30 that is a polyethylene-based resin foam sheet is attached to the side surface on the crest side of the formed “layer made of resin foam”. Although the thickness of the heat insulating sheet 30 depends on how much the sheet has a heat insulating performance, it may be about several mm to 20 mm. After the heat insulating sheet 30 is attached, or in parallel with the attaching operation, the light-weight mixed soil is placed in the space S surrounded by the “layer made of the resin foam” and the natural ground 2. . Ordinarily, it is cast to a depth of about 1 m, waits for its curing, and after it is cured, it is repeatedly cast on it, and filled with a lightweight foamed mixed soil to the required height. The light-weight and light-mixed soil is hardened to become a lightweight embankment 5.
[0019]
Reaction heat is generated when the lightweight mixed soil is cured, but heat transfer to the “layer made of the resin foam” is prevented by the heat insulating sheet 30, so that the resin foam is thirdarily foamed. Does not occur. Further, the weight of the concrete layer 21 prevents the block-shaped resin foam 20a from floating due to the buoyancy generated by the uncured cellular lightweight mixed soil. After that, by performing the required construction of the surface pavement 6 and the like, the structure by the bubble light weight mixed earth method according to the present invention is completed.
[0020]
FIG. 5 shows another form of the structure according to the invention. In this example, flat retaining walls 10a and 10a are erected using concrete foundations 4a and 4a constructed with a predetermined width on the ground 3, and a space between the left and right retaining walls 10a and 10a. A lightweight foamed mixed soil is placed in S to form a lightweight embankment 5, and a pavement 6 is formed thereon to form a road. Even in this case, “layers made of resin foam” (block-shaped resin foams 20a and 20b) are in close contact with the inner side surfaces of the retaining walls 10a and 10a, similar to those shown in FIGS. are formed by state, the concrete layer 21 is formed between the block-shaped resin foam 20a and 20b, also heat-insulating sheet 30 on the inner surface of the "layer of the resin foam" is formed . In FIG. 5, 51 and 52 are waterproofers, and 53 is an L-shaped retaining wall that defines the width of the road.
[0021]
In the present invention, when the required stability required for the structure is ensured, the above-described “concrete layer 21” and / or “heat insulating sheet 30” may be omitted. FIG. 6 shows a construction example in which the “concrete layer 21” is omitted, and the block-shaped resin foam 20 is continuously stacked up to a required height to form a “layer made of resin foam”. FIG. 7 is a construction example in which both the “concrete layer 21” and the “heat insulating sheet 30” are omitted, and the inner side surface of the “layer made of resin foam” which is the block-shaped resin foam 20 and the light weight. It is in direct contact with the embankment 5.
[0022]
Although not shown, in the structure as shown in FIGS. 1 to 4, after making the footing 11, a “layer made of resin foam” is formed, and concrete is used by using it as a formwork. The retaining wall portion of the abutment 10 may be made by placing it. Also, in the construction of the structure as shown in FIG. 5, a “layer made of a resin foam” may be formed first, and the retaining wall 10 a may be made by using it as a mold. . The subsequent steps are the same as in the other embodiments.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to effectively prevent the occurrence of cracks in the light-weight embankment that is the light-bubble mixed soil in the structure using the light-bubble mixed soil construction method. Moreover, since the side pressure which acts on a retaining wall can be reduced when a bubble lightweight mixed soil is unhardened, construction of a retaining wall can also be simplified.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a first diagram illustrating a structure according to a light-weight and lightweight mixed earth method according to the present invention together with its construction procedure.
FIG. 2 is a diagram for explaining a construction procedure following FIG. 1;
FIG. 3 is a view for explaining a construction procedure following FIG. 2;
[Figure 4] is a view for explaining the subsequent construction process in FIG. 3 shows the completed structure.
FIG. 5 is a view showing another embodiment of the structure by the light-weight lightweight mixed earth method according to the present invention.
FIG. 6 is a view showing still another embodiment of a structure according to the light-weight and lightweight mixed earth method of the present invention.
FIG. 7 is a view showing still another embodiment of a structure according to the light-weight lightweight mixed earth method according to the present invention.
FIG. 8 is a view showing an example of a structure according to a conventional bubble lightweight mixed earth method.
FIG. 9 is a view showing another example of a structure by a conventional bubble lightweight mixed earth method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Abutment as retaining wall, 11 ... Footing part of abutment, 20, 20a, 20b ... Layer made of resin foam (block-shaped resin foam), 21 ... Concrete layer, 30 ... Foam resin that functions as heat insulation layer Sheet: 1 ... Bridge, 2 ... Ground mountain embankment, 3 ... Ground, 5 ... Lightweight embankment, 6 ... Pavement

Claims (5)

In a structure using a lightweight lightweight mixed earth method with at least a retaining wall erected on the ground and an embankment with a lightweight foamed mixed soil, the retaining wall is placed between the inner surface of the retaining wall and the lightweight embankment with a lightweight lightweight mixed soil. A layer made of a resin foam is formed in close contact with the inner surface, and a foamed resin sheet functioning as a heat insulating layer is further disposed between the layer made of the resin foam and the lightweight embankment. A structure characterized by The structure according to claim 1, wherein the retaining wall is an abutment having a footing, and the layer made of the resin foam is disposed at least on the footing. Claim 1 or 2, wherein the resin layer comprising the foam is composed of stacked obtained resin foam block in multiple stages, and is in place of the vertical direction is formed concrete layer extending horizontally structure according to. After setting up the retaining wall on the ground, a lightweight embankment was formed by placing a lightweight mixed soil in the space surrounded by the ground and the retaining wall or in the space surrounded by the retaining wall and the retaining wall. In the construction method of the structure by the cellular lightweight mixed earth method, as a step before placing the cellular lightweight mixed soil, it has at least a step of arranging a layer made of a resin foam on the inner surface of the retaining wall, and then A construction characterized in that a foamed resin sheet functioning as a heat insulating layer is disposed between the layer made of the resin foam and the lightweight embankment, and a lightweight embankment is formed by placing a lightweight foamed mixed soil. Method.   After setting up the retaining wall on the ground, a light-weight embankment was formed by placing bubble lightweight mixed soil in the space surrounded by the ground and the retaining wall or in the space surrounded by the retaining wall and the retaining wall. In the construction method of the structure by the cellular lightweight mixed earth method, as a process before placing the cellular lightweight mixed soil, a step of forming a layer made of resin foam and using it as a formwork to build a retaining wall The construction method is characterized in that, after that, a light-weight embankment is formed by placing a light-weight light-mixed soil.

Images