JPH02104823A - Constructing method for retaining wall using artificial lightweight soil - Google Patents

Abstract

PURPOSE:To prevent differential settlement and landslide from being generated and enable work to be executed with machines and shorten the term of construction by placing lightweight soil mixture between the face of slope and a mold, and by repeating the placing on the upper section gradually in the same manner after solidifying, to construct a retaining wall. CONSTITUTION:On the lower ground surface E of ready-set filling 1, a concrete-tile- shaped form 2 with an anchor section 2b fitted on the rear side surface is constructed steeper than the face W1 of slope. After that, the lightweight soil mixture A of earth B, aqueous solution C with foaming agent dissolved in water, bubble D for foaming the foaming agent with compressed air, and concreting agent E which are mixed with each other, is placed between the form 2 and the face W2 of slope, up to the level of the form 2. Besides, after the mixture A is concreted, the following step form 2 is set on the lower step form 2, and the form is repeatedly placed gradually, and a retaining wall 3 is constructed. As a result, the load of ground pressure or the like is not applied to the form 2, and ground settlement is prevented from being generated, and the weight of the mixture A is light, and so a grade can be set to be steep, and upper and lower land areas to be used can be widened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of constructing a retaining wall using artificial lightweight soil.

(Prior art) The construction method for constructing a retaining wall on the slope of an existing earthen structure is, for example, in the case of a masonry retaining wall, masonry is constructed on the front side of the slope;
After that, the back side was filled with backfill soil, backfill gravel, etc., and at the same time construction of drainage vibrators, etc. was also carried out.

(Problem to be solved by the invention) However, in this stone masonry retaining wall construction method, masonry and backfilling are sequentially constructed on the front of the slope, alternating and repeating, so mechanized construction is not possible and the construction is time-consuming. Another disadvantage was that there was a shortage of masonry technicians, resulting in a long construction period.

Additionally, because mechanized construction is not possible, the construction of the masonry retaining wall and the backfilling work at the back of the wall are delayed, which tends to cause uneven settlement on the surface due to compaction of the backfilling soil at the back of the retaining wall.

Furthermore, if the slope of the retaining wall is steep, landslides are likely to occur due to the earth pressure caused by the embankment and backfilling, so in order to maintain the stability of the retaining wall, it is necessary to construct the retaining wall with a gentle slope. . However, if the slope is made gentle in this way, the land area above or below the retaining wall will be reduced accordingly, making it impossible to use the land effectively.

This invention solves the above-mentioned drawbacks; it can be constructed mechanized, there is no uneven settlement due to compression, and landslides do not occur even if the slope of the retaining wall is made steep; therefore, the land area above and below the retaining wall is The purpose of the present invention is to provide a method of constructing a retaining wall using artificial lightweight soil that allows for a wide range of walls.

(Means for Solving the Problems) In order to achieve the above object, the present invention uses natural soil such as sandy soil or clay soil, or industrial by-products such as fly ash and blast furnace slag, as the soil constituting the retaining wall. Alternatively, use a mixture of these mixtures, a foaming agent that generates air bubbles, or air bubbles made by foaming the foaming agent, and a solidifying agent, and mix and stir the mixture, and apply the mixture sequentially between the slope of the existing site and the formwork. By repeating pouring and consolidation at a predetermined height, a lightweight earth structure with a predetermined slope is constructed in a layered manner on the slope of an existing site.

Further, in the present invention, the formwork includes a plate-shaped main body made of concrete or the like, and an anchor material provided on the back side of the main body, and the lightweight earth structure is laminated on the back side of the formwork. By constructing the structure and burying the anchor material in this lightweight earth structure, the formwork can be integrated in a completely buried state.

Furthermore, with this invention, a new steeply sloped retaining wall can be built by cutting away the slope of an existing site.

(Function) According to the above configuration, the lightweight soil mixture poured between the existing site and the formwork will solidify and become an artificial lightweight soil structure. Furthermore, after consolidation, a lightweight soil mixture is successively placed on top of the concrete in the same manner, and by repeating this process, the retaining wall is completed.

Therefore, no load such as earth pressure is applied to the formwork, and no ground subsidence occurs.

When concrete is used as the formwork, the lightweight earth structure has both the function of backfilling earth and sand and the function of reinforcing the retaining wall.

The resulting retaining wall can have a steep slope because the lightweight soil mixture is lightweight, and depending on the difference in slope from the slope of the existing site,
The upper land area or the lower land area can be expanded.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

FIGS. 1 and 2 show a case in which the present invention is applied to a method of constructing a retaining wall constructed on the slope of an expressway on existing embankment.

In the figure, the existing embankment 1 whose upper part is expressway right-of-way 1a
A formwork 2 having a steeper slope than the slope Wt of the existing embankment 1 is constructed on the lower ground surface E.

Incidentally, on the slope W2 shown in FIG. 1, the existing slope Wl is slightly excavated in order to install the formwork 2.

As shown in FIGS. 2(a) and 2(b), the formwork 2 is formed into a concrete tile-like unit with a predetermined size, and the formwork 2 is formed into a concrete tile-like unit with a predetermined size to provide the desired support. ! The mold body 2a is provided with a flat form body 2a forming the surface of the mold body 3.

Anchor materials 2b arranged vertically and horizontally are provided on the back side of the formwork main body 2a, and the formwork 2 is propped against a slope by the anchor materials 2b so that the main body 2a is at a predetermined angle. It is installed at a predetermined distance from W2.

Next, while the formwork 2 is in the constructed state, a drainage filter F is laid on the lower ground surface E thereof.

After completing the above preparations, the lightweight soil mixture A is poured into the gap between the formwork 2 and the existing embankment 1 and solidified, thereby forming the artificial lightweight soil structure 6 in a layered manner with the two integrally connected. Constructed.

In this case, in order to fix the formwork 2, the lightweight soil mixture A corresponding to the entire height of the formwork 2 is not poured at once, but an appropriate amount is poured. The remaining amount may be poured later.

As shown in FIG. 1, the lightweight soil mixture A is manufactured by a manufacturing plant installed on the surface of the upper site 1a of the existing embankment 1, and is successively poured.

This lightweight soil mixture A is foamed by supplying soil B and an aqueous solution C in which a foaming agent such as a surfactant and animal hydrolyzed protein is dissolved in water together with compressed air to the foamer 7. It is produced by putting the bubbles produced by foaming the agent and the solidifying agent E1, such as cement slurry, into a continuous mixer (J--8) and mixing and stirring them with the mixer 8.

The prepared lightweight soil mixture A was cast between the slope W2 of the existing embankment 1 and the formwork 2 by the belt conveyor 9, and the casting opening reached almost the top of the formwork 2. Stop the pouring work in this condition. The poured lightweight soil mixture A contains the consolidation agent E, so it consolidates with air bubbles in it.
, the lightweight earth structure 6 is constructed in a state integrated with the back surface of the formwork 2 by consolidation.

After this work is completed, the next work of constructing the formwork 2 is performed.

In this embodiment, this work is carried out by installing the formwork 2 of the next stage on top of the formwork 2 of the lowest stage so that it is continuous and has the same slope. It can also be steeply sloped.

Even in this case, a filter F is installed on the surface of the lightweight soil structure 6, and the lightweight soil mixture A is applied to the existing embankment J as described above.
Repeat pouring between the mold and formwork 2 and solidifying.

In the final stage, the top of the uppermost formwork 2 is installed so that it is on the same horizontal plane as the upper ground 1a of the existing embankment 1, and after installing the filter F, it is placed in the gap between this formwork 2 and the existing embankment 1. By pouring lightweight soil mixture A and solidifying it,
Construction of retaining wall 3 is completed.

In the completed state, the formwork main body 2a constitutes the surface of the retaining wall 3, and the anchor material 2a at the back thereof is buried in the lightweight soil mixture A, so that the formwork 2 is buried in the lightweight soil structure. It is integrated with 6.

17. In this embodiment, when the retaining wall 3 is completed, the upper expressway land 1a can be widened in accordance with the difference in slope between the existing embankment and the formwork 2.

In the figure, the formwork 2 is stacked in three tiers, but this is due to the size and formwork of the formwork 2, the height of the slope W2, and the amount of time required to stack the formwork 2 before the compaction of the lightweight soil mixture A. Determined by the applied lateral pressure, etc.

Further, the formwork 2 may be constructed of commonly used water-resistant plywood or the like; in this case, by removing the formwork 2 after completion of construction, the exposed surface of the lightweight earth structure 6 becomes the surface of the retaining wall 3. Can be done.

In general, the above-mentioned lightweight soil mixture A can be used as soil B, including soil excavated on site, sandy soil transported from other places, natural soil such as viscous soil, or fly ash. , blast furnace slag, and other industrial byproducts can be used alone or in combination.

Furthermore, instead of air bubbles, inorganic foaming agents such as aluminum powder or hydrogen peroxide foaming agents can also be used, and when these are used, the foaming device 7 is not required and the foaming agent is mixed with soil and sand B. Lightweight soil mixture A can be obtained simply by mixing with solidifying agent E and stirring.

Furthermore, considering promotion of weight reduction and cost reduction, it is recommended to mix a weight reducing agent such as porous rapidly cooled blast furnace slag or blast furnace expanded slag into the artificial lightweight soil A. Furthermore,
To ensure the compressive strength and shear strength of the lightweight soil A in accordance with the design specifications, cement, fly ash, pulverized blast furnace slag powder, etc. can be used alone or in combination as the solidifying agent E.

If water permeability is required, the unit water amount of the solidifying agent E may be reduced.

Further, in the above embodiments, the lightweight soil mixture was produced at the construction site, but it may also be manufactured in advance and transported to the pouring site using a dump truck or the like while being mixed and stirred.

FIG. 3 shows a second embodiment of the invention.

In the example shown in the figure, a slope W shown by an imaginary line of an existing site 20 is excavated to create a new steep slope W', and this slope W
- By alternately repeating the construction of the formwork 2 and the pouring of the lightweight soil mixture A in a layered manner in the same manner as in the first embodiment, a lightweight soil structure 6 is formed on the back side of the formwork 2. The construction of the retaining wall 21 is now completed.

In this embodiment, the existing site 20 has a width L1 according to the slope difference.
At the same time, the lower site 20a is also widened by the width L2.

FIG. 4 shows a third embodiment of the invention.

In this embodiment, the slope W of this is placed on the lower side of the existing embankment 30.
Construct a concrete retaining wall main body 31 with a steeper slope than
A retaining wall 3 in which the retaining wall main body 31 and the lightweight soil structure 6 are integrated by sequentially pouring the lightweight soil mixture A in a layered manner on the back surface of the retaining wall 3
We are trying to complete the construction of 2. In this embodiment as well, the width of the upper site 30a can be widened as in the first embodiment.

(Effects of the Invention) As explained in detail in the examples above, in the method for constructing a retaining wall using artificial lightweight soil according to the present invention, after the poured lightweight soil mixture is solidified, Unlike traditional masonry construction methods, the construction can be mechanized and the construction period can be shortened. In addition, the constructed retaining wall will not self-collapse even if the slope is steep, and depending on the difference between the slope of the retaining wall and the slope of the existing site, the land area of the upper side or the lower side The land area can be expanded.

The constructed lightweight artificial earth structure is lightweight and solidifies gradually, so it does not apply loads such as earth pressure to the formwork, and does not cause ground subsidence after pouring.

When a concrete retaining wall is used as the formwork, it serves both the function of backfilling earth and sand and the function of reinforcing the retaining wall.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram showing the first embodiment of this invention, and the second
Figures (a) and (b) are explanatory diagrams of concrete formwork used in the same embodiment, Figure 3 is a cross-sectional diagram showing a second embodiment of this invention, and Figure 4 is a third embodiment of this invention. FIG. A...Lightweight soil mixture B...Soil Sand C
...Aqueous solution D ... Air bubbles E.
・・・・Solidifying agent 1.20.30・・・・Existing embankment (existing site) 1a
...Expressway land (upper side land) 2...type
Frame 3.21.32...Retaining wall 6...Artificial lightweight earth structure 20a...Lower side site 30a...Upper side site 31...Retaining wall main body W, W-...Slope patent applicant Obayashi Kumijo Ri Co., Ltd.
People Patent Attorney - Color Ken Axis
Patent attorney Masatoshi Matsumoto 3rd rl! l Figure 4

Claims (3)

[Claims] (1) As the soil that makes up the retaining wall, natural soil such as sandy soil or clay soil, or industrial by-products such as fly ash and blast furnace slag may be used alone or in combination, and a foaming agent or foaming agent that generates air bubbles is used. By using a mixture of foamed air bubbles and a solidifying agent mixed and stirred, the mixture is successively cast at a predetermined height between the slope of the existing site and the formwork, and the process is repeated to solidify the existing site. A method for constructing a retaining wall using artificial lightweight soil, which is characterized by constructing a layered lightweight soil structure with a predetermined slope on the slope of the site. (2) The formwork includes a plate-shaped main body made of concrete or the like, and an anchor material provided on the back side of the main body, and the lightweight earth structure is constructed in a layered manner on the back side of the formwork. The method for constructing a retaining wall using artificial lightweight soil according to claim 1, characterized in that the anchor material is buried in the lightweight soil structure to integrate the formwork in a buried state. . (3) The method for constructing a retaining wall using artificial lightweight soil according to claim 1 or 2, characterized in that a new retaining wall with a steep slope is constructed by scraping away the slope of the existing site. .