JP4036989B2 - Embankment structure to control / prevent soil acidification - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a banking structure for suppressing and preventing soil acidification in banking piled up on an inclined ground.
[0002]
[Prior art]
In construction work on sedimentary soft rocks and marine diluvium, pyrite contained in soil due to excavation and landfall is oxidized and weathered in a short time by oxygen in the air, and rainwater penetrates into the soil. As a result, soil oxidation continues for a long period of time, and acid water continues to flow out, causing problems with so-called “acidic sulfate soils”. Soil acidification and acid water outflow mainly occur in excavated soil embankments (depots), but as countermeasures against these problems, conventionally, alkaline materials such as slaked lime have been added to and mixed with excavated soil. Or, mortar is sprayed on the excavated embankment to block the surface of the embankment to block oxygen, and the acid water that has flowed out is collected and neutralized by water treatment equipment.
[0003]
[Problems to be solved by the invention]
However, among the measures described above, the method of charging and mixing alkaline materials is troublesome because it requires a large amount of alkaline materials to be charged and mixed into the soil, and is disadvantageous in terms of workability and economy. Moreover, the method by surface water shielding / oxygen shielding is disadvantageous in terms of the certainty of the effect. The method using water collection and water treatment is surely effective, but it is known that there are many disadvantages in terms of economy and the length of the implementation period, and it exceeds the capacity of the treatment facility due to heavy rainfall. When rainwater flows in, acid water often flows out.
[0004]
The present invention focuses on the above-mentioned problems of the prior art, and is intended to solve this problem. The problem is that it satisfies the requirements for acidification suppression and effect sustainability in a short period of time, and is economically excellent in construction. It is to provide an embankment structure that makes it possible.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a banking structure for suppressing and preventing soil acidification in banking piled up on an inclined ground, and intersects the tilting direction at the tilting upper end and tilting lower end of the embankment. Provided is an embankment structure characterized in that an underground wall containing an alkaline material is formed in the embankment over the entire length and depth in the direction. The embankment structure of the present invention can be applied to any existing embankment or newly created embankment.
[0006]
Here, in addition to the slope upper end and the slope lower end of the embankment, the underground wall can be appropriately disposed in the middle portion thereof. Moreover, the material which comprises the said underground wall should just be an alkaline material, for example, lime-based materials, such as limestone, quicklime, slaked lime, and cement, and cement was mixed with excavated embankment soil (acid soil), and it improved to alkalinity. Industrial waste-based alkaline materials such as improved soil, papermaking waste incineration ash (paper sludge ash), sewage sludge incineration ash, coal ash and RDF ash (waste power generation ash) can be used. Furthermore, in the underground wall, a crushed rock or a crushed layer may be provided in the deepest part by stacking crushed limestone to a particle size of about 5 to 15 cm.
[0007]
In the embankment structure of the present invention, in the sloped ground, an area where the underground wall at the bottom of the slope is disposed is excavated to form a recess, and the recess is backfilled with a material containing an alkaline material such as limestone. An underground wall at the lower end of the slope may be provided on the return portion. Here, it is preferable that the concave portion is formed in a grounded portion of the underground wall in the inclined ground and in a range extending downward from the grounded portion.
[0008]
In the embankment structure of the present invention, a storage structure for damming up leachate from the embankment may be provided on the backfill portion at a position further spaced downward from the underground wall at the lower end of the slope.
[0009]
【Example】
Hereinafter, although an example is described based on an accompanying drawing, the present invention is not limited to this. FIG. 1 is a perspective view showing the embankment structure of the present invention, and FIG. 2 is a cross-sectional view of the embankment structure of FIG. In FIG. 1 and FIG. 2, the embankment 11 is piled up on an inclined ground 20, and the upper end neutralization wall 12, sandwiching the original embankment portions 13 and 13, respectively, on the inclined upper end, the inclined lower end, and the intermediate portion of the embankment 11, A lower end neutralization wall 15 and an intermediate neutralization wall 14 are provided, and a weir 16 as a storage structure for damming leachate from the embankment on an inclined ground 20 separated from the lower end neutralization wall 15 by a predetermined length downward from the lower end neutralization wall 15. Is provided.
[0010]
Here, each neutralization wall 12, 14, 15 is formed to a depth reaching the inclined ground 20 by excavating the embankment original soil over the entire length in the direction intersecting the inclination direction of the embankment 11. Moreover, each neutralization wall 12,14,15 is improved soil which mixed the cement-type solidification material with the embankment original soil excavated and discharged in order to construct a neutralization wall, and improved limestone or slaked lime. Use to form. The improved soil may be used as a part of the material for constructing the weir 16, or may be used as a part of the material when a water shielding layer is provided on the embankment surface as necessary. it can. As described above, if the neutralization walls 12, 14, and 15 are provided, the rainwater that has permeated from the embankment at the upper end of the slope is neutralized at each neutralization wall, and the alkaline components are dissolved into the rainwater and the raw embankment. It flows through the portion 13 and reacts with the acidic soil contained in the raw embankment portion 13 to produce a neutralizing action. Therefore, since the neutralization walls 12, 14, and 15 containing the alkaline material are only partially provided on the sloped upper end, the sloped lower end and the middle part of the embankment 11, the labor on construction can be reduced, and The required amount of alkaline material can also be reduced.
[0011]
Further, in the deepest part of each neutralization wall 12, 14, 15, that is, the part grounded on the inclined ground of each neutralization wall 12, 14, 15, as illustrated in FIG. The crushed limestone may be piled up to provide a crushed wall 21a or a crushed layer 21b. The creation of such a crushed wall 21a and a crushed layer 21b contributes to improving the stability of the embankment, and also acts like a filter layer, so that the effect of quickly discharging the permeated water in the embankment can be obtained. .
[0012]
Further, as shown in FIG. 4, a backfill layer 24 can be provided on the inclined ground 20 below the lower end neutralization wall 15. When this backfill layer 24 constructs the lower end neutralization wall 15, after excavating the embankment raw soil, it further excavates an inclined ground 20 as a natural ground to form a recess 23, and this recess 23 is formed into limestone, It is formed by backfilling with a material containing an alkaline material such as quick lime, slaked lime, cement, papermaking waste incineration ash (paper sludge ash), sewage sludge incineration ash, coal ash or RDF ash (waste power generation ash). The concave portion 23 is formed in a range extending downward from the ground contact portion of the lower end neutralization wall 15, that is, a range including the ground contact portion of the lower end neutralization wall 15 and the weir 16 in the inclined ground 20.
[0013]
As described above, if the backfill layer 24 is provided, the acid water that has passed through the embankment 11 without being neutralized and has reached the lower end neutralization wall 15 stays in the recesses 23 of the backfill layer 24. It can be neutralized by reacting with an alkaline material as a backfill material. The acidic water 17 flowing on the embankment surface or leached from the lower end neutralization wall 15 is dammed between the lower end neutralization wall 15 by the weir 16, and a backfill layer 24 is provided here. Therefore, acidic water can still be neutralized.
[0014]
【The invention's effect】
In the embankment structure of the present invention, since the underground wall containing an alkaline material such as limestone is provided at the upper end of the slope and the lower end of the slope, the rainwater that has permeated the embankment at the upper end of the slope reaches the underground wall of the upper end of the slope, The alkaline component dissolves in rainwater and flows through the embankment, reacts with the acidic soil contained in the embankment, and neutralizes it. In addition, rainwater flowing through the embankment and not sufficiently neutralized is surely neutralized here when it reaches the underground wall at the lower end of the slope. Therefore, compared with the prior art in which an alkaline material is charged and mixed over the entire area of the embankment, it is possible to reduce the labor and time required for the construction and to reduce the required amount of the alkaline material.
[0015]
In the embankment structure of the present invention, the slope ground where the bottom wall of the slope is arranged is excavated and backfilled with a material containing an alkaline material such as limestone. The rainwater that reaches and flows downwardly can be reliably neutralized in this backfill portion. Therefore, the acidification inhibitory effect can be obtained continuously over a long period of time.
[0016]
Furthermore, in the embankment structure of the present invention, since the storage structure is provided on the backfill portion at a position separated from the underground wall at the lower end of the slope, the acidic water leached from the embankment is stored in the storage structure. Is neutralized by reacting with the alkaline material in the backfill portion. Therefore, the labor for construction can be reduced, and the required amount of alkaline material can also be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embankment structure according to the present invention.
FIG. 2 is a cross-sectional view of the embankment structure of FIG.
FIG. 3 is a cross-sectional view showing an inclined lower end of the embankment different from FIG. 2;
4 is a cross-sectional view showing a banking structure different from those shown in FIGS. 2 and 3. FIG.
[Explanation of symbols]
11 Filling (filling structure)
12 Neutralization wall at the top (ground wall at the top of the slope)
13 Original embankment part 15 Lower end neutralization wall (ground wall at the lower end of the slope)
16 Weir (storage structure)
20 Inclined ground 23 Concave 24 Backfill layer (backfill part)

Claims (3)

An embankment structure for suppressing and preventing soil acidification in an embankment piled up on an inclined ground, the upper end and the lower end of the embankment, over the entire length and the entire depth in the direction intersecting the inclining direction, An embankment structure characterized by the formation of underground walls containing alkaline materials in the embankment. In the inclined ground, an area where the underground wall of the inclined lower end is disposed is excavated to form a concave portion, and the concave portion is backfilled with a material containing an alkaline material. The embankment structure according to claim 1, wherein an underground wall is provided. 3. The embankment according to claim 2, wherein a storage structure for damming up leachate from the embankment is provided on the backfill portion at a position further spaced downward from the underground wall at the lower end of the slope. Construction.

Images