JP2003082649A - Improvement method of soft ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improvement method of a soft ground capable of uniformly compacting the soft ground and being simply carried out down to a deeper layer section of the ground by positively making use of a property expanded by water absorption belonging to steel making slags. SOLUTION: The insides of excavated holes H excavated into the soft ground 1 at predetermined intervals are filled with the slags 21 having expansiveness, and the slags 21 absorb water content into the soft ground to compact the ambient ground by expanding the slags 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving soft ground, and in particular, the property of expanding by absorbing water by converter slag and / or electric furnace slag (herein referred to as "steel making slag"). The present invention relates to an improved construction method for soft ground, in which the soft ground is compacted and the water content of the soft ground is reduced.

[0002]

2. Description of the Related Art Conventionally, in order to prevent liquefaction at the occurrence of an earthquake in soft ground and to ensure the safety of structures on the ground, sand is excavated in the soft ground at regular intervals,
Drain piles are formed by filling a permeable material such as crushed stone to drain the water in the ground to the surface layer.

[0003]

By the way, since the conventional method for improving soft ground is to fill a hole in the soft ground with a water-permeable material such as sand or crushed stone, the holes are excavated at a predetermined interval. However, the ground cannot be consolidated, and when filling a water-permeable material such as sand or crushed stone, the ground is consolidated by applying mechanical vibration or compressive force.
For this reason, when it is attempted to promote the consolidation of the ground, there is a problem that large vibrations and noises are generated, which disturbs the surroundings and requires a large mechanical device, which increases the construction cost. Also, in the case of a method of applying vibration or compressive force by a mechanical device, it is difficult to uniformly consolidate the entire ground around the pile, and in particular, it is not possible to efficiently transmit the consolidating force to the deep layer and It was difficult to consolidate the ground of some parts.

In view of the problems of the conventional method for improving soft ground, the present invention positively utilizes the property of steelmaking slag that expands by absorbing water, thereby uniformly compacting soft ground. Moreover, it is an object of the present invention to provide an improved method for soft ground, which is capable of easily performing even deep layers of the ground.

By the way, since steelmaking slag has a property of expanding when it absorbs water, its use as a material for civil engineering and construction is currently limited. For example, when the steelmaking slag is used as a sand drain pile or roadbed material, the expansive property of the steelmaking slag causes a problem on the contrary,
In utilizing the steelmaking slag, the slag that the steelmaking slag has is eliminated by performing an aging treatment in which it is held in steam at about 100 ° C. for about 100 hours. As described above, the use of steelmaking slag is costly in terms of energy consumption for eliminating and removing the expansivity, so that it is not always effectively used, and especially the development of uses of steelmaking slag without aging treatment. The current situation was that

[0006]

In order to achieve the above object, the invention according to claim 1 excavates in soft ground at a predetermined interval by utilizing the property of steelmaking slag that expands by absorbing water. The excavation hole is filled with expansive slag, and the slag absorbs moisture in the soft ground to expand the slag and compact the surrounding ground.

According to the first aspect of the present invention, the slag filled in the excavation hole expands by absorbing moisture in the soft ground around the excavation hole, and statically compacts the surrounding ground. Therefore, it is possible to uniformly consolidate, and further, it is possible to consolidate the deep ground.

Further, the invention according to claim 2 is characterized in that the slag pillars placed in the soft ground that has expanded and hardened by absorbing the moisture in the soft ground have water permeability. To do.

According to the invention of claim 2, expansion,
Moisture in the soft ground can be discharged through the slag pillars cast on the hard ground.

The invention according to claim 3 is characterized in that a drainage layer made of a water-permeable material such as crushed stone is formed on the surface portion above the slag filled in the excavation hole.

According to the third aspect of the present invention, the moisture in the soft ground can be more reliably discharged to the outside.

The invention according to claim 4 is characterized in that the expansion coefficient of the slag to be filled is adjusted according to the properties of the ground.

According to the fourth aspect of the present invention, the surrounding ground can be compacted to the required strength by the expansion of the slag whose expansion coefficient is adjusted according to the properties of the ground.

Further, in the invention according to claim 5, the slag is the steelmaking slag before aging treatment alone, or the steelmaking slag is the main component, and the steelmaking slag after aging treatment, the blast furnace slag, the ferroalloy slag, Industrial waste such as granulated slag, copper smelting slag, red mud, fly ash, refuse incineration slag, refuse incineration ash, sludge slag, crushed glass, waste gypsum, concrete waste materials, gypsum, quick lime,
It is characterized in that the expansiveness of steel-making slag obtained by mixing one or more of building materials such as cement, crushed stone, earth and sand, clay, artificial materials, and minerals can be used.

According to the invention of claim 5, the aging treatment of the steelmaking slag is not required, so that the steelmaking slag can be used at low cost and the steelmaking slag can be effectively used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for improving soft ground according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a method for improving soft ground according to the present invention. This method for improving soft ground is a method of hitherto known in the soft ground 1 to be improved, for example, by placing a steel pipe casing, etc. The slag 21 having the slag 21 is filled so as to have a predetermined density.
It is characterized in that the slag 21 is expanded to absorb the moisture contained therein to compact the surrounding ground.

In this case, the diameter and spacing of the drill holes H and the packing density of the slag 21 are determined by the characteristics of the soft ground 1 and the slag 21.
It can be appropriately determined in consideration of the expansion coefficient and the like.

The shape of the excavation hole H is a straight shape in the present embodiment, but depending on the characteristics of the ground or a building to be built on this improved ground, etc.
If necessary, the upper portion may be formed in an arbitrary shape such as having a large diameter.

Further, the expansive slag 21 to be filled in the drill hole H is steelmaking slag, preferably steelmaking slag before aging treatment alone or containing this steelmaking slag as a main component, and subjecting it to aging treatment. Later steelmaking slag, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud (aluminum smelting slag), fly ash, waste incineration slag, waste incineration ash, sludge slag, glass crushed material, waste gypsum, concrete Industrial waste such as waste materials, plaster,
Building materials such as quick lime, cement, crushed stone, earth and sand, clay,
It is possible to use an artificial material or a mixture of one or more kinds of minerals, which can utilize the expandability of the steelmaking slag.

Since the steelmaking slag before aging treatment has a particularly remarkable property of expanding by absorbing water, it can be suitably used for the method for constructing a pile of the present invention.

FIG. 2 shows the results of an expansion test based on JIS A 5015 using steelmaking slag having a grain size of 5 mm under and before aging treatment. As is clear from FIG. 2, the expansion characteristics (expansion rate) of the steelmaking slag before aging treatment differ depending on the environment, temperature, blending, chemical composition and the like.

The granulated slag has innumerable bubbles,
Since it has an angular shape, it has light weight, large shear resistance, water permeability, and hydraulic property, and can be suitably used for the method for constructing a pile of the present invention.

Then, the slag 2 having such characteristics
By filling 1 into the excavation hole H, when the ground is sand ground, at least until the slag 21 is solidified,
The pore water can be discharged smoothly, and the liquefaction of the ground at the time of an earthquake can be prevented, and the slag 21 expands by absorbing the water in the soft ground around the drilled hole H, Since the surrounding ground is statically compacted, it can be uniformly consolidated, and since the deep ground can be similarly consolidated, the hydraulic ratio of the steelmaking slag increases the mixing ratio of the steelmaking slag. The uniaxial compressive strength of the slag column 2 increases and the bearing capacity is improved, so that the bearing capacity of the ground can be increased. Utilizing this property, depending on the properties of the ground, for example, by using the slag whose expansion rate is adjusted according to the properties of the formation at the position in the depth direction of the drilled hole H, the expansion of the slag causes the surroundings to expand. The ground can be compacted to the required strength. In this way, change the expansion rate of slag according to the depth,
By compensating the surrounding ground, and by appropriately combining slags with different expansion coefficients and water absorption properties according to the characteristics of the ground, it is possible to cope with the ground with a complicated stratum structure. To do. This makes it possible to more effectively compact the surrounding ground even in the deep layer.

By adjusting the particle size of the slag 21 as appropriate, the slag pillars 2 cast into the soft ground 1 that has expanded and hardened by absorbing the water in the soft ground 1 have water permeability. You can As a result, the moisture in the soft ground 1 can be discharged through the slag columns 2 cast on the expanded and hardened soft ground 1, and the pore water can be smoothly discharged even after the slag 21 is solidified. By doing so, it will be possible to prevent the liquefaction of the ground in the event of an earthquake, together with the compaction of the surrounding ground.

Further, in this embodiment, a drainage layer 22 made of a permeable material such as crushed stone is formed on the ground surface above the slag 21 filled in the excavation hole H, and the embankment 3 is further formed thereon. . In this case, as the water-permeable material used for the drainage layer 22, in addition to crushed stone, it is possible to use any granular material such as slag whose expansiveness has been eliminated by aging treatment. When the expandability of the steelmaking slag does not pose a problem, a steelmaking slag having the same expandability before aging treatment as the slag 21 filled in the drilled hole H, preferably filled in the drilled hole H, is used. It is also possible to use a material having a particle size larger than that of the slag 21. Thereby, the water in the soft ground 1 can be more reliably discharged to the outside via the slag 21 (slag column 2) filled in the excavation hole H.

Although the method for improving soft ground according to the present invention has been described above based on the embodiments thereof, the present invention is not limited to the structures described in the above embodiments. Drilling hole H to increase force
When the slag 21 is filled in the inside, the structure can be appropriately changed within a range not departing from the gist thereof, such as inserting a precast pile such as a node pile.

[0028]

According to the invention of claim 1, the slag filled in the excavation hole expands by absorbing moisture in the soft ground around the excavation hole, and statically tightens the surrounding ground. Since it is solidified, it can be uniformly consolidated, and further, the deep ground can be similarly consolidated. Further, at this time, in combination with compaction of the soft ground, since the water content of the soft ground is reduced by absorbing water in the soft ground by the slag, the soft ground can be reliably consolidated.
As a result, the supporting force of the ground can be increased. Furthermore, since the ground can be statically compacted and consolidation can be promoted, a large mechanical device that generates large vibration and noise is not required, and the construction cost can be reduced.

According to the second aspect of the invention, the slag pillars placed on the soft ground that has expanded and hardened,
Water in the soft ground can be discharged, for example, liquefaction can be prevented when an earthquake occurs, and the safety of structures on the ground can be improved.

According to the third aspect of the present invention, the moisture in the soft ground can be more reliably discharged to the outside, for example, liquefaction at the time of earthquake occurrence can be prevented, and the structure on the ground can be prevented. The safety of can be further improved.

According to the fourth aspect of the present invention, the surrounding ground can be compacted to the required strength by the expansion of the slag whose expansion rate is adjusted according to the properties of the ground.

Further, according to the invention of claim 5, since the aging treatment of the steelmaking slag is not required, the steelmaking slag can be used at low cost and the steelmaking slag can be effectively used.

[Brief description of drawings]

FIG. 1 shows an example of construction of a method for improving soft ground according to the present invention, in which (A) is a vertical sectional view of ground and (B) is an explanatory view showing expansion characteristics of slag.

FIG. 2 is an explanatory diagram showing expansion characteristics of a steelmaking slag before aging treatment.

[Explanation of symbols]

H drilling hole 1 Soft ground to be improved 2 slag pillars 21 Slag with expansiveness in the borehole 22 Drainage layer 3 embankments

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sadao Yabuuchi             2-10 Koraibashi, Chuo-ku, Osaka City, Osaka Prefecture               Geo Top Co., Ltd. F-term (reference) 2D043 CA02 CA11 EA01 EA04 EA05                       EA06

Claims (5)

[Claims] 1. A digging hole excavated at a predetermined interval in soft ground is filled with expansive slag, and the slag absorbs moisture in the soft ground, thereby expanding the slag to expand the surrounding ground. An improved method for soft ground, characterized by compaction. 2. A slag column placed on soft ground that has expanded and hardened by absorbing water in the soft ground,
The method for improving soft ground according to claim 1, which has water permeability. 3. The method for improving soft ground according to claim 1 or 2, wherein a drainage layer made of a permeable material such as crushed stone is formed on the ground surface above the slag filled in the excavation hole. . 4. The method for improving soft ground according to claim 1, 2 or 3, wherein the expansion coefficient of the slag to be filled is adjusted according to the properties of the ground. 5. A steelmaking slag before aging treatment, or a steelmaking slag as a main component, wherein the slag is a steelmaking slag after aging treatment, blast furnace slag, ferroalloy slag, water granulated slag, copper smelting slag, Industrial waste such as red mud, fly ash, waste incineration slag, waste incineration ash, sludge slag, crushed glass, waste gypsum, concrete waste, etc., gypsum, quick lime, cement, crushed stone, earth and sand, building materials such as clay, artificial The method for improving soft ground according to claim 1, 2, 3 or 4, wherein the expandability of a steelmaking slag obtained by mixing one or two or more of materials and minerals can be utilized.