JP2003253662A - Work method for measures against liquefaction of ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work method for measures against the liquefaction of a ground capable of supporting a placed load by chuting and filling slag produced when steel is produced inside an outer peripheral wall surrounding the specified range of a sand ground where liquefaction is liable to occur to easily improve the ground over a wide range at a low cost. <P>SOLUTION: The outer peripheral wall 1 is constructed under the ground by using concrete so as to surround the surroundings, the entire ground constructing an upper structure 4 is dug from a surface layer to a ground capable of supporting the upper structure, and slag 2 is chuted and filled inside the outer peripheral wall 1. Thus, the ground can be improved by utilizing the inflation and solidification of the slag 2 caused by water absorption. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing liquefaction of ground, and particularly to a steelmaking slag before aging treatment and an inner side surrounded by an outer peripheral wall constructed in soft ground where liquefaction is likely to occur. / Or liquefaction prevention of the ground by filling the steelmaking slag after aging treatment (hereinafter sometimes referred to simply as "slag") by utilizing the property of slag that expands due to water absorption It is related to the countermeasure construction method.

[0002]

2. Description of the Related Art Conventionally, converter slag has been used as a material for improving the ground, and piles are driven into the soft ground layer by a pile driving machine, and the water absorption expansion effect of the slag is utilized to remove the ground. There is an improved method (see, for example, Japanese Patent Laid-Open No. 6-116937).

[0003]

By the way, in the above-mentioned conventional measures against soft ground, a converter slag is used to improve the ground by its water absorption expansion action. However, this converter slag is piled up. Since it is directly driven into the soft ground by the construction machine, it has the effect of consolidating the ground by driving piles, the dehydration and consolidation of the soft ground due to the capillary phenomenon of the slag, and the effect of water absorption and expansion to compress the ground. However, since this converter slag is piled directly into the soft ground, the ground improvement area for the top load is limited to the periphery of the pile, and a large number of piles are piled up for wide-range improvement. However, there is a problem that it takes a lot of time and money to improve the ground.

In view of the problems of the above-mentioned conventional ground improvement measures, the present invention provides a slag produced during steelmaking on the inside of the outer peripheral wall which surrounds a predetermined range of the sand ground where liquefaction is likely to occur. An object of the present invention is to provide a method for preventing liquefaction of ground, which is capable of easily and inexpensively improving the ground over a wide range by adding and filling it, and being able to cope with a top load.

[0005]

In order to achieve this object, the method for preventing liquefaction of the ground according to the present invention constructs an outer peripheral wall in the ground by using concrete so as to surround the surroundings, and at the same time, constructs an upper structure. Excavate the entire ground from the surface layer to the ground that can support the upper structure, put the slag inside the outer peripheral wall, fill it, and use the expansion and solidification due to the slag absorbing water to form the ground. It is characterized by being improved.

This method for preventing liquefaction of the ground is to construct a peripheral wall in the ground by using concrete so as to surround the surroundings, and to support the upper structure from the surface layer of the entire ground for constructing the upper structure. Excavation up to, inward of the outer peripheral wall, throwing in and filling slag, since the slag is designed to improve the ground by utilizing the expansion and solidification property by absorbing water, by absorbing water by the slag, Excessive pore water in the ground can be drained smoothly by utilizing the characteristics of slag, liquefaction of the ground can be prevented in advance, and after the ground is strengthened by the expansion and hardening action of the slag, it is overlaid. Since the bearing capacity corresponding to the load can be obtained, the improvement of the sand ground or the like, which is likely to be liquefied, can be easily and reliably performed. Further, even if excess pore water in the unimproved ground is fluidized outside the outer peripheral wall due to an earthquake or the like, the outer peripheral wall acts as a blocking wall, and the outer peripheral wall is prevented from entering the improved ground. Therefore, it is possible to reduce the influence of the fluidization of the surrounding ground.

In this case, the outer peripheral wall has a circular shape, and a plurality of PC steel wires are laid between the outer peripheral walls facing each other inwardly surrounded by the outer peripheral wall, and at substantially equal intervals in the circumferential direction of the outer peripheral wall. So that the PCs are stretched so that the positions of the PCs are changed with each other.
The steel wire can be prestressed.

As a result, when the slag filled inward surrounded by the outer peripheral wall expands and hardens, lateral expansion is restrained by the outer peripheral wall, the PC steel wire is naturally prestressed, and the tensile force of the ground is exerted. Can be strengthened, and the entire ground can be solid ground.

Further, the slag which is surrounded by the outer peripheral wall and which is filled inwardly can be made so that the peripheral portion is low and the central portion rises and swells.

As a result, the improved ground is integrated and the overload can be supported on the entire ground, so that it is suitable for the foundation of a structure such as a petroleum storage tank that supports a load on a large area, and further improved. The impermeability of the ground prevents the oil from penetrating into the ground when it leaks.

Further, it is possible to integrally construct a lattice-shaped wall body inwardly surrounded by the outer peripheral wall.

As a result, the interior of the ground improvement area is partitioned by the grid-like walls, so that even in a large area of ground,
Ground improvement adapted to the geology of each section can be easily performed.

As the slag, the steelmaking slag before aging treatment and / or the slag of the steelmaking slag after aging treatment alone, or the steelmaking slag before aging treatment and / or the steelmaking slag after aging treatment, blast furnace slag, and ferroalloy Slag, water granulated slag, copper smelting slag, red mud, fly ash, garbage incineration slag, garbage incineration ash, sludge slag, glass crushed material, waste gypsum, industrial waste such as concrete waste materials, gypsum, quicklime, cement, crushed stone, It is possible to use a mixture of a building material such as earth and sand, an artificial material, and one or more kinds of minerals, which can utilize the expansion and solidification properties of the steelmaking slag. Where "steel slag"
The term “converter slag” and / or electric furnace slag (oxidizing slag and / or reducing slag) is used.

As a result, the slag layer ground that is stronger due to the expansion and solidification of the steelmaking slag can be obtained, and the low-cost steelmaking slag can be used, and the steelmaking slag can be used more effectively. be able to.

Further, the reducing slag of the electric furnace slag can be used as the slag.

As a result, the expandability is further improved, so that a stronger slag layer ground can be obtained.

[0017]

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

FIG. 1 shows a first embodiment of a method for preventing liquefaction of ground according to the present invention. When constructing an upper structure such as a building 4 or a petroleum storage tank 5 on a soft ground such as sandy soil,
It is necessary to prevent the liquefaction of soft ground, which is likely to occur due to an earthquake, etc., and to improve the ground so that it can bear the top load.

Therefore, in order to improve the ground having a preset area, the outer peripheral wall 1 is constructed in the ground by using concrete so as to surround the periphery of a portion where a predetermined upper structure is constructed, and at the same time, the upper structure is constructed. The whole ground for constructing the object is excavated from the surface layer to the ground capable of supporting the upper structure, and the slag 2 is charged and filled inside the outer peripheral wall 1.

In this case, as the slag to be charged and filled inside the outer peripheral wall 1, those having expansion and solidifying characteristics can be preferably used. Specifically, aging treatment (slag having a predetermined particle size) can be used. Steel slag before aging treatment and / or slag of steelmaking slag after aging treatment, or slag of steelmaking slag before aging treatment, or steelmaking slag before aging treatment and / or aging treatment Industrial steelmaking slag and industrial waste such as blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud, fly ash, waste incineration slag, waste incineration ash, sludge slag, glass crushed material, waste gypsum, concrete waste Materials, building materials such as plaster, quick lime, cement, crushed stone, earth and sand, clay, artificial materials, minerals To so that.

Further, by using the reducing slag of the electric furnace slag for the slag, the expandability is further improved, and thus a stronger slag layer ground can be obtained.

Further, by using the earth and sand of the ground layer to replace the slag and the like within the range where the object of the present invention is not lost, the amount of residual soil generated can be suppressed and the construction cost can be reduced.

In this way, the charge is put inside the outer peripheral wall 1.
The free lime remaining in the slag 2 expands when the filled slag 2 reacts with water and expands. Therefore, especially when the main purpose is to utilize this expandability, the one before aging is used. It is desirable to use. This slug,
In particular, granulated slag has innumerable bubbles and has an angular shape, so it has light weight, large shear resistance, and water permeability, so it is filled by its water permeability before expansion hardening by water absorption. The slag itself drains the excess pore water in the ground, and part of the excess pore water contained in the ground to be improved absorbs the slag itself, expands with this water absorption, and solidifies. can do. Further, it has water impermeability after curing, and can suppress the influence of unimproved surrounding ground, and can firmly improve the ground. The water absorption expansion of this slag can also be performed by proper water addition.

By the way, when the slag 2 filled inside the outer peripheral wall 1 expands due to water absorption, the outer peripheral wall 1 is constrained by the lateral (horizontal) expansion force in the outer peripheral wall 1, and The pressing force will be applied from the surrounding ground, the compression and bending rigidity of the outer peripheral wall 1 will increase, and the expansion force will act in the vertical direction as well, and this expansion force will correspond to the overlaid load and bending resistance of the ground. Therefore, the soft ground can be easily and surely improved over a wide range.

By the way, the outer peripheral wall 1 which is constructed so as to surround the periphery of a portion where a predetermined upper structure is constructed is a prism,
The shape may be arbitrary, such as a circle, depending on the shape and type of the upper structure constructed on the ground. Specifically, for example, in the case of a superstructure such as a building, it is desirable to make it a square shape that matches the shape of the building, and in the case of an oil storage tank, a circular shape. It is not limited. When the outer peripheral wall 1 is, for example, a prism, the outer peripheral wall 1 is constructed only on the outer peripheral portion as shown in FIG. 2 (A), and as shown in FIG. It is also possible to construct the lattice wall body 11 integrally with the outer peripheral wall 1 so as to be partitioned into a shape.

Then, inside the outer peripheral wall 1, the lattice wall body 11 is provided.
Even if the geology in each section surrounded by the outer peripheral wall 1 and the lattice wall 11 is different, the soil improvement corresponding to each geological feature can be performed by integrally forming the You can Especially when improving a wide area of ground at the same time, the geology often differs depending on the location. The improvement method is suitable for such a case, and the entire ground can be improved on average. Further, even in a construction area where construction cannot be carried out at once, the construction can be carried out separately for each section.

When the load is applied to almost the entire upper structure such as the oil storage tank 5, the outer peripheral wall 1 may be formed in a circular shape as shown in FIGS. it can. The circular outer peripheral wall 1 can be constructed similarly to the rectangular outer peripheral wall 1.

In this case, a section steel 6 such as an H section steel is further embedded in the outer peripheral wall 1 and a PC steel wire 3 is stretched between the section steels 6.
The PC steel wire 3 is stretched between the opposing wall surfaces of the outer peripheral wall 1 so as to pass through the center of the circular outer peripheral wall 1 or the vicinity thereof, and the PC steel wire 3 is provided at predetermined intervals along the circumferential direction of the circular outer peripheral wall 1. Arrange and stretch each. As a result, when the slag 2 filling the inside of the outer peripheral wall absorbs water and expands, the expansion direction of the slag 2 is
It acts not only in the radial direction but also in the vertical direction over the entire circumference of the outer peripheral wall. In particular, since the expansion force acting in the radial direction over the entire circumference of the outer peripheral wall is restricted by the outer peripheral wall, P
The C steel wire is given tension, and the tensile force of the ground can be strengthened. In the illustrated embodiment, the PC steel wire 3 is stretched in a planar shape, but in addition to this, the PC steel wire 3 may be stretched in a plurality of stages of two or more stages in the height direction. Therefore, the tensile force of the ground can be further strengthened. Further, since a uniform restraining force acts on the outer peripheral wall, it is possible to prevent the outer peripheral wall from being broken due to stress concentration.

The slag that fills the inside of the outer peripheral wall 1 may be arched so that the side along the inner peripheral surface of the outer peripheral wall is low and the central portion of the outer peripheral wall rises. As a result, when the slag is filled, the central part is raised, but when the slag absorbs water and expands, the expansion force of this slag acts on the outer peripheral wall side and the surface of the improved ground is flat. The ground is integrated so that the whole ground can support the overlaid load. Therefore, it is suitable for a foundation of a structure that supports a load in a large area such as a petroleum storage tank 5, and can improve the impermeability of the ground to prevent penetration into the ground when oil leaks. .

The method for preventing liquefaction of the ground according to the present invention has been described above based on a plurality of embodiments, but the present invention is not limited to the configurations described in the above embodiments, and the embodiments are not limited to these. The configurations can be appropriately changed within a range not departing from the spirit of the invention, such as appropriately combining the described configurations.

[0031]

According to the ground liquefaction prevention countermeasure construction method of the present invention, an outer peripheral wall is constructed in the ground by using concrete so as to surround the periphery, and at the same time, the whole ground for constructing the upper structure is constructed from the surface layer to the top. It excavates to the ground that can support the structure, puts and fills the slag inside the outer peripheral wall, and improves the ground by utilizing the expansion and solidification property due to the slag absorbing water. By absorbing water, excess pore water in the ground can be drained smoothly by utilizing the characteristics of the slag, liquefaction of the ground can be prevented in advance, and the ground is strengthened by the expansion hardening effect of the slag. Since the bearing capacity can be made to correspond to the overlaid load after the removal, it is possible to easily and surely improve the sand ground or the like which is likely to be liquefied. Further, even if excess pore water in the unimproved ground is fluidized outside the outer peripheral wall due to an earthquake or the like, the outer peripheral wall acts as a blocking wall, and the outer peripheral wall is prevented from entering the improved ground. Therefore, it is possible to reduce the influence of the fluidization of the surrounding ground.

Further, the outer peripheral wall has a circular shape, and a plurality of PC steel wires are laid between the outer peripheral walls facing each other inwardly surrounded by the outer peripheral wall, and they are arranged at substantially equal intervals in the circumferential direction of the outer peripheral wall. As shown in FIG. 2 and arranged so as to change their arrangement positions with respect to each other, and by prestressing the PC steel wire by the expansion of the filling slag, the inside is surrounded by the outer peripheral wall. When the filled slag expands and hardens, the expansion of the lateral direction is restrained by the outer peripheral wall, the PC steel wire is naturally prestressed, and the tensile force of the ground can be strengthened, making the whole ground a solid ground. be able to.

Further, the slag that is filled inwardly surrounded by the outer peripheral wall is designed so that the peripheral portion is low and the central portion is raised and swells, so that the improved ground is integrated and the overload is overloaded on the entire ground. Since it can be supported, it is suitable for the foundation of structures that support loads on large areas such as oil storage tanks, etc. Furthermore, improved impermeable properties of the ground prevent penetration into the ground when oil leaks. be able to.

Further, by constructing a lattice-like wall body integrally inside the outer peripheral wall, the interior of the ground improvement area is partitioned by the lattice-like wall body. Also, the ground improvement adapted to the geology of each section can be easily performed.

As the slag, the steelmaking slag before aging treatment and / or the slag of steelmaking slag after aging treatment alone, or the steelmaking slag before aging treatment and / or the steelmaking slag after aging treatment, blast furnace slag, and ferroalloy Slag, water granulated slag, copper smelting slag, red mud, fly ash, garbage incineration slag, garbage incineration ash, sludge slag, glass crushed material, waste gypsum, industrial waste such as concrete waste materials, gypsum, quicklime, cement, crushed stone, Due to the expansion and solidification of the steelmaking slag, by using a material that can utilize the expansion and solidification properties of the steelmaking slag, which is a mixture of building materials such as earth and sand, artificial materials, and one or more kinds of minerals, It is possible to obtain a stronger slag layer ground,
Moreover, low-cost steelmaking slag can be used, and the steelmaking slag can be used more effectively.

Further, by using the reducing slag of the electric furnace slag for the slag, the expandability is further improved, and thus a stronger slag layer ground can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of a construction method for preventing liquefaction of ground according to the present invention.

FIG. 2 is a cross-sectional plan view of the first embodiment of the present invention, (A) shows a case without a lattice wall body, and (B) shows a case where the lattice wall body is integrally formed.

FIG. 3 is a vertical cross-sectional view showing a second embodiment of the construction method for preventing liquefaction of ground according to the present invention.

FIG. 4 is a transverse sectional view of the same.

[Explanation of symbols]

1 outer wall 11 Lattice wall 2 slag 3 PC steel wire 4 building (upper structure) 5 Oil storage tank (upper structure) 6 shaped steel

Claims (6)

[Claims] 1. An outer peripheral wall is constructed in the ground by using concrete so as to surround the periphery, and the entire ground for constructing the upper structure is excavated from the surface layer to the ground capable of supporting the upper structure, and the outer wall of the outer wall is constructed. A method for preventing liquefaction of the ground, characterized in that the slag is charged and filled inward, and the slag absorbs water to expand and solidify to improve the ground. 2. The outer peripheral wall has a circular shape, and a plurality of PC steel wires are stretched inwardly surrounded by the outer peripheral wall between opposing outer peripheral walls, and the outer peripheral walls are arranged at substantially equal intervals. 2. The ground according to claim 1, wherein the PC steel wire is prestressed by the expansion of the filling slag so that the PC steel wire is stretched and arranged so as to change their positions. Liquefaction prevention method. 3. The liquid of the ground according to claim 1, wherein the slag which is filled inwardly surrounded by the outer peripheral wall is formed so that the peripheral portion is low and the central portion is raised and swells. Anti-oxidation measures construction method. 4. The method for preventing ground liquefaction according to claim 1, wherein a lattice-shaped wall body is integrally formed inwardly surrounded by the outer peripheral wall. 5. The slag is a steelmaking slag before aging treatment and / or a slag of steelmaking slag after aging treatment alone, or a steelmaking slag before aging treatment and / or a steelmaking slag after aging treatment, and a blast furnace slag and a ferroalloy slag. , Granulated slag, Copper smelting slag, Red mud, Fly ash, Waste incineration slag, Waste incineration ash, Sludge slag, Glass crushed material, Waste gypsum, Industrial waste such as concrete waste material, Gypsum, quick lime, cement, crushed stone, earth and sand A mixture of one or two or more of building materials such as clay and clay, artificial materials, and minerals, which can utilize the expansion and solidification properties of the steelmaking slag. Construction method of foundation ground described in 4. 6. The method for constructing a foundation ground according to claim 1, 2, 3, 4, or 5, wherein the slag is a reducing slag of the electric furnace slag.