JPS5839970B2 - Chikashijikou Zoubutsukouchikuhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type of drain construction method for reducing the moisture content of soft soil, and it is possible to use gamma columnar bodies as foundation piles for drains, and is also advantageous and easy to install. The purpose of this paper is to provide a method for improving soft soil that can be implemented.

In conventional drain construction methods, sand, gravel, coral acid, water slag, etc. were used as the main material for the drain.
None of these have supporting force, and if a curing agent is added and cured to provide supporting force, the porosity will be significantly reduced due to the curing agent that has hardened between the particles of the main material for the drain.
Its water absorbency and water permeability are lost, and the drain effect disappears.

Therefore, if these were to be used for foundation piles for temporary construction, the soil would have hardened sufficiently and no drain action would be necessary, but it would have to be hardened with fill cement, etc., which would require a long construction period.

For this reason, in the past, foundation piles were driven separately.

Furthermore, the conventional drainage method using sand, gravel, coral acid, water slag, etc. mentioned above stabilizes the ground by applying a load and removing the excess water pressure caused by the concentrated stress caused by this load. This method requires structural equipment, increases the number of handling steps, and has the drawbacks of poor workability.

In view of these circumstances, the present invention is advantageous in construction, and allows the drain column to be used as it is as a foundation pile for temporary construction even at the stage where drain action is required. This paper aims to propose methods for improving soil.

Therefore, the method for improving soft soil according to the present invention involves artificially applying ash obtained by incinerating sludge or urban garbage, or powder and granules obtained by mixing a hydraulic material into the ash to a considerable depth from the surface of soft soil. The ash is set up vertically in the form of a column, and the ash is combined with the pore water in the soft soil to harden the ash to form a column, and the column lifts the surrounding pore water to the soil surface. Features.

Therefore, the ash commonly obtained by incinerating sludge or municipal waste is composed of SiO2, which undergoes a pozzolanic reaction.
T-rice containing ingredients such as Al2O3 and CaO has hydraulic properties, and products with additional hydraulic materials are more useful for improving soft soils with high water content because they harden quickly and reliably. It is porous due to volatile components generated during the firing process, and the apparent value of less than 1.0 indicates specific gravity, and the porosity is 30% not only in the uncured state but also after curing. Because it has high water absorption and water permeability comparable to that of sand, it is difficult to promote consolidation using conventional Q sand, gravel, coral sand, water slag, etc., without taking special drainage measures. Compared to piles that apply a load to the foundation, there is no need to use hardening means to promote consolidation, and although it can be used as a foundation pile for temporary construction, it still The piles themselves have a draining effect due to capillary action, and therefore structures can be built on the ground without having to completely harden the soil, which shortens the construction period. Because the excellent drainage effect described above is achieved by simply erecting ash with excellent water absorption in the form of columns, it does not require any special means to promote compaction as in conventional methods, making it extremely easy and inexpensive. Moreover, they were able to quickly achieve their desired goal.

In addition, since it exhibits a good drainage effect even after hardening, it is possible to harden the ground by draining rainwater, etc., without having to take any special drainage measures, as described above, even after building a structure. I came to Shieru.

An example of the method according to the present invention will be explained below.

Commonly obtained sewage sludge incineration ash, that is, sludge discharged from sewage treatment plants, is filtered and dehydrated by mixing filter aids such as quicklime or slaked lime, iron salts, and organic polymer flocculants.
The water content is reduced to ~80%, and the sludge is normally formed into a porous material by calcination, but if necessary, calcium carbonate (CaCO5) or calcium hydroxide (Ca(OH)) may be added to this dehydrated sludge to make it even more porous. As shown in item 2, evaporative decomposition and porosity-inducing substances (e.g., rubber (powder slag, raw sludge, etc.) is then heated to 700-800°C or 90°C.
If the ash obtained by firing at a mixed temperature of 40°C to 1,000°C or this ash has no or weak hydraulic properties, water (or at least one of hard materials such as cement, calcined gypsum, quicklime, etc.) Powder material 1 mixed with about 5% by weight or more of one or more types
For example, by filling the water-permeable cylindrical body 2 such as wire mesh, kraft paper, Pax, etc., about 1
By creating a light columnar body 3 with a diameter of about 50 m, and standing this light columnar body 3 in soft soil 4 such as a clay layer or bottom sediment layer as shown in Fig. 2, the soft soil around this columnar body 3 can be reduced. soil 4
The pore water in the layer is absorbed to lower the water content ratio of the soil layer, and at the same time, the columnar bodies 3 themselves are hardened, and the hardened columnar bodies 3 are used as temporary underground columns.

Incidentally, when carrying out the method of the present invention described above, it is also possible to use only the granular material without using the water-permeable cylindrical body 2 and to erect it in the form of a column, but when using the water-permeable cylindrical body 2, Even materials with weak hydraulic properties can be reliably maintained in a columnar shape, making it more effective in obtaining materials.

In addition, when erecting a column made only of powder material, a hard casing such as a steel pipe is erected in a vertical hole drilled in the ground, and the casing is removed and the powder material is erected in the soil in the form of a column. You may also use the construction method.

Furthermore, in the present invention, as shown in FIG. 3, the granular material 1 is spread on the soft soil surface on which the columnar bodies 3 are erected, forming a layer thicker than about 50 cm, and then, for example, on the soft soil surface. By constructing a temporary road for automobiles, it is possible to economically construct a temporary road with a very acceptable strength due to the bridging effect on the surface.

Of course, the columnar body of the present invention exhibits sufficient effects as a building foundation when combined with permanent piles such as concrete piles.

A table showing the chemical components and physical properties of sewage sludge incineration ash, urban garbage incineration ash, etc. is shown below.

From the values of unit volume weight in the table above, it can be seen that the apparent specific gravity is lower than that of water, and the higher the porosity, the better the water absorbency.

Regarding water permeability, see the table below. It turns out that it is about the same level as normal sand.

Furthermore, due to the large presence of SiO2, Al2O3, and CaO, a bob run reaction occurs, resulting in hydraulic properties.

[Brief explanation of the drawing]

The drawings show an example of the method for improving soft soil according to the present invention, in which Fig. 1 is a partially cutaway perspective view of a columnar body, Fig. 2 is a vertical cross-sectional view of the construction state, and Fig. 3 is another example of construction. FIG.

Claims (1)

[Claims] 1. Gamma ash obtained by incinerating sludge or urban garbage, or granular material obtained by mixing the ash with a hydraulic material, is artificially erected in a pillar shape to a considerable depth from the surface of soft soil, and the soft soil is A method for improving soft soil in which the ash is hardened by associating with the pore water within the soil to form columns, and the columns pump up surrounding pore water to the soil surface.