JPH083183B2 - Retaining wall construction method using artificial lightweight soil - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for constructing a retaining wall using artificial lightweight soil.

<Conventional technology> For example, in the case of a masonry retaining wall, masonry is performed on the front side of the slope, and then backfilling soil, backfilling gravel, etc. It was filled on the back side, and at this time, construction of a discharge pipe and the like was also performed.

<Problems to be solved by the invention> However, in this retaining wall construction method using masonry, masonry and backfilling are alternately repeated on the front surface of the slope to construct sequentially, so mechanized construction cannot be performed, and construction work is troublesome. In addition, there was a shortage of masonry engineers, which had the drawback of lengthening the construction period.

Moreover, since mechanized construction is not possible, the timing of construction of the masonry retaining wall and the backfilling work on the back side of the retaining wall is different, so that the settlement of the backfilling soil on the backside of the retaining wall tends to cause uneven settlement on the surface.

Furthermore, if the retaining wall has a steep slope, landslides are likely to occur due to the earth pressure due to the embankment and backfilling. Therefore, it is necessary to construct the retaining wall with a gentle slope in order to keep the retaining wall stable. . However, such a gentle slope would reduce the site area above or below the retaining wall by that amount, and could not effectively use the site.

This invention solves the above-mentioned drawbacks, can be mechanized, has no differential settlement due to compression, and does not cause landslides even if the slope of the retaining wall is steep. Therefore, the land area above and below the retaining wall is reduced. It is an object of the present invention to provide a method for constructing a retaining wall using an artificial lightweight soil that can be widely used.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention uses, as earth and sand constituting a retaining wall, natural soil such as sandy soil and cohesive soil, fly ash, and industrial by-products such as blast furnace slag. Alternatively, a mixture obtained by mixing and agitating a mixture of these mixtures with a foaming agent or a foaming agent for generating bubbles and a solidifying agent is used, and the mixture is sequentially placed between the slope of the existing site and the formwork. By repeatedly placing and solidifying at a predetermined height, a lightweight soil structure having a predetermined slope was constructed in a laminated manner on the slope of the 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 backside of the formwork. Then, by embedding the anchor material in the lightweight earth structure, the form can be buried and integrated.

Further, in the present invention, the slope of the existing site can be shaved to construct a new steep retaining wall.

<< Working >> According to the above configuration, the lightweight soil mixture placed between the existing site and the formwork is solidified into an artificial lightweight soil structure. In addition, after consolidation, the lightweight soil mixture is sequentially placed on the upper part in the same manner, and the retaining wall is completed by repeating this.

Therefore, no load such as earth pressure is applied to the formwork, and ground subsidence does not occur.

If you use concrete as the formwork,
The lightweight soil structure has both the function of backfilling sand and the function of reinforcing the retaining wall.

The obtained retaining wall can be made steep because the lightweight soil mixture is lightweight, and the upper side land area or the lower side land area can be widened according to the difference from the slope of the slope of the existing land.

<< Example >> An example of the present invention will be described below in detail with reference to the drawings.

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

In the figure, the existing embankment 1 whose upper part is the expressway site 1a
On the lower ground surface E of, the formwork 2 having a steeper slope than the slope of the slope W1 of the existing embankment 1 is constructed.

As for the slope W2 shown in FIG. 1, the existing slope W1 is slightly excavated in order to install the mold 2.

As shown in FIGS. 2 (a) and 2 (b), the formwork 2 is formed into a concrete tile-shaped unit of a predetermined size,
A plate-shaped mold body that constitutes the surface of the retaining wall 3 to be obtained
It has 2a.

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

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

After the above preparation is completed, the lightweight soil mixture A is cast in the gap between the formwork 2 and the existing embankment 1 and solidified to form the artificial lightweight soil structure 6 in a laminated state in which both are integrally connected. Be built.

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 cast at one time, but is stopped once with an appropriate amount placed, and after the mixture A has solidified to some extent. The remaining amount may be set.

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

This lightweight soil mixture A is prepared by supplying earth and sand B and a foaming agent, for example, an aqueous solution C in which a surfactant and an animal hydrolyzed protein are dissolved in water together with compressed air to a foaming machine 7 to generate the foaming agent. The foamed foam D and the solidifying agent E, such as cement slurry, are charged into a continuous mixer 8 and the mixer 8
It is prepared by mixing and stirring these.

The produced lightweight soil mixture A is placed between the slope W2 of the existing embankment 1 and the formwork 2 by the belt conveyor 9, and the amount of placement is almost at the top of the formwork 2. Stop the placing work. Since the poured lightweight soil mixture A contains the solidifying agent E, it is consolidated in a state of containing the bubbles D, and the lightweight soil structure 6 is integrated on the back surface of the form 2 by the consolidation. Built in.

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

In this embodiment, this work is carried out by a method of installing the formwork 2 of the next stage on the formwork 2 of the lowermost stage so as to be continuous and at the same gradient. Can also be steep.

Even in this case, the filter F is installed on the surface of the lightweight soil structure 6, and the lightweight soil mixture A is placed between the existing embankment 1 and the form 2 and solidified as described above. .

At the final stage, the top of the top formwork 2 is replaced with the existing embankment 1.
It is provided so as to be on the same horizontal plane as the upper ground 1a, and after the filter F is installed, the lightweight soil mixture A is placed in the gap between the formwork 2 and the existing embankment 1 and is solidified,
Construction of the 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 on the back side thereof is embedded in the lightweight soil mixture A, whereby the formwork 2 is buried and the lightweight soil structure is formed. It is integrated with 6.

Then, in this embodiment, in the completed state of the retaining wall 3, the upper expressway site corresponding to the difference in slope between the existing embankment 1 and the formwork 2
A widening width L of 1a can be obtained.

In the figure, the formwork 2 is stacked in three stages, but this is added to the formwork 2 by the size and weight of the formwork 2, the height of the slope W2, and the consolidation of the lightweight soil mixture A. Determined by lateral pressure etc.

Further, the form 2 may be composed of a commonly used waterproof plywood or the like. In this case, if the form 2 is removed after the completion of construction,
The exposed surface of the lightweight earth structure 6 can be the surface of the retaining wall 3.

Furthermore, the above lightweight soil mixture A can be used as the soil B, in addition to the soil excavated at the site, sandy soil transported from other places, natural soil such as cohesive soil, or fly ash, Industrial by-products such as blast furnace slag can be used alone or as a mixture.

Furthermore, in place of the air bubbles D, an inorganic foaming agent such as aluminum powder or hydrogen peroxide foaming agent can be used. When these are used, the foaming device 7 is not required, and the foaming agent is earth and sand B. The lightweight soil mixture A can be obtained simply by mixing with the solidifying agent E and stirring.

Further, in consideration of promotion of weight reduction and cost reduction, it is recommended to mix artificial lightweight soil A with a lightening agent such as porous blast furnace rapidly cooled slag or blast furnace expanded slag. Furthermore, in order to secure the compressive strength and the shear strength according to the design specifications of the lightweight soil A, cement as the solidifying agent E, fly ash, blast furnace slag fine powder, lime or the like can be used alone or in combination.

When water permeability is required, the unit water content of the solidifying agent E may be reduced.

Further, although the lightweight soil mixture was prepared at the construction site in the above-mentioned embodiment, it may be manufactured in advance and conveyed to the construction site by a dump truck while mixing and stirring.

 FIG. 3 shows a second embodiment of the present invention.

In the embodiment shown in the drawing, the slope W shown by the imaginary line of the existing site 20 is ground to form a new steep slope W ', and along the slope W'parallel to the first embodiment. Similarly, by alternately repeating the construction of the formwork 2 and the work of placing the lightweight soil mixture A in a laminated form, the construction of the retaining wall 21 in which the lightweight soil structure 6 is integrated on the back surface of the formwork 2 is completed. I have to.

In this embodiment, the existing site 20 is expanded by the width L1 and the lower site 20a is expanded by the width L2 in accordance with the gradient difference.

 FIG. 4 shows a third embodiment of the present invention.

In this embodiment, the slope W of the existing embankment 30 is located on the lower side of the embankment 30.
Retaining wall 32 in which the retaining wall body 31 and the lightweight earth structure 6 are integrated by constructing a concrete retaining wall body 31 having a steeper slope than that and placing the lightweight soil mixture A on the back surface thereof in a layered order. I am trying to complete the construction of. In this embodiment as well, the upper site 30a can be widened as in the first embodiment.

<< Effects of the Invention >> As described in detail with reference to the above examples, in the construction method of the retaining wall using the artificial lightweight soil according to the present invention,
Unlike the conventional masonry method, mechanized construction is possible and the construction period is shortened, because the placed lightweight soil mixture is solidified and then sequentially placed in the same manner. In addition, the constructed retaining wall does not collapse on its own even if the slope is steep, and depending on the difference between the retaining wall slope and the slope of the existing site, the upper side land area or the lower side The land area can be expanded.

The constructed artificial lightweight soil structure is lightweight and does not apply a load such as earth pressure to the formwork because it solidifies sequentially, and does not cause ground subsidence after placement.

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

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing a first embodiment of the present invention, and FIG.
(A) and (b) are explanatory views of a concrete formwork used in the same embodiment, FIG. 3 is a sectional explanatory view showing a second embodiment of the present invention, and FIG. 4 is a third embodiment of the present invention. It is sectional explanatory drawing which shows. A: Lightweight soil mixture, B: Sediment C: Aqueous solution, D: Air bubbles E: Solidifying agent 1,20,30 ... Existing embankment (existing site) 1a ... Expressway site (upper site) 2 …… Formwork 3,21,32 …… Retaining wall 6 …… Artificial lightweight earth structure 20a …… Lower side site 30a …… Upper side site 31 …… Retaining wall body W, W ′ …… Slope

Claims (3)

[Claims] 1. As earth and sand constituting a retaining wall, natural soil such as sandy soil and cohesive soil, and industrial by-products such as fly ash and blast furnace slag, or a mixture thereof, and a foaming agent or foaming agent for generating bubbles. Using a mixture obtained by mixing and stirring a foaming agent and a solidifying agent, the mixture is repeatedly placed and fixed at a predetermined height between the slope of the existing site and the formwork to repeat the solidification. By doing so, a method for constructing a retaining wall using artificial lightweight soil is characterized in that a lightweight soil structure with a predetermined slope is constructed in layers on the slope of the existing site. 2. The formwork comprises 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 backside of the formwork. 2. The retaining wall using artificial lightweight soil according to claim 1, characterized in that the formwork is buried and integrated by burying the anchor material in the lightweight soil structure. Construction method. 3. The retaining wall using artificial lightweight soil according to claim 1 or 2, wherein the slope of the existing site is shaved to construct a new steep retaining wall. Construction method.