JP4184113B2 - Method for increasing horizontal resistance of piles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a horizontal resistance enhancement method piles, in particular, it is possible to construction a simple device, and improved compacted around soil near the pile head, horizontal resistance enhancement method of piles which can enhance the ground reaction force it relates to.
[0002]
[Prior art]
Conventionally, several techniques for increasing the horizontal resistance of pile foundations have been proposed.
For example, as a conventional method for increasing the horizontal resistance of a pile, the pile diameter of the embedded pile placed in soft ground is sized to match the vertical bearing force required to support the superstructure, and the pile head of this embedded pile is The outer peripheral ground in the vicinity of the soft ground in the horizontal direction over a range of several times the diameter of the pile, and in the depth direction over a depth range of several times to a dozen times the horizontal range from the top edge of the ground. There is a method of improving the ground and increasing the horizontal resistance of the pile by the bearing effect of the ground improved portion (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent No. 3127276 [0004]
The horizontal resistance of this pile is increased by excavating the vicinity of the pile head to a large diameter by the pre-boring method, injecting cement milk, making soil cement, improving the ground, and then burying the pile in the vicinity of the pile head. The horizontal resistance of the pile is increased by the bearing effect of the ground improvement part.
[0005]
[Problems to be solved by the invention]
However, the conventional method for increasing the horizontal resistance of a pile is limited to the pre-boring method and the ground around the soft hole wall near the pile head has not been improved. It is considered that the reaction force is small, the integrity of the pile and the improved layer is lost, and as a result, the horizontal resistance of the pile is difficult to increase.
In addition, since it is necessary to excavate the vicinity of the pile head to a large diameter, there is a problem that the construction cost increases, the amount of soil generated increases, and the surrounding ground near the pile head is loosened. .
[0006]
In view of the problems of the conventional method for enhancing the horizontal resistance of a pile, the present invention can be constructed with a simple device regardless of the construction method, and the surrounding ground near the pile head is compacted and improved, and the ground reaction force to increase the, and to provide a horizontal resistance enhancement method of piles which can enhance the integrity of the pile and improvements layer.
[0007]
[Means for Solving the Problems]
To achieve the above first, the horizontal resistance enhancement method of pile of the present invention, by vibrating the pile head of the pile that built up in the ground in the horizontal direction or the circumferential direction, and pile head of pile, the surrounding A gap is formed between the ground and the filler, and the gap is filled with a granular filler.
Here, the "pile that built up on the ground", in addition to the ready-made pile, is intended to include a cast-in-place pile.
[0008]
In this case, after filling the void with powdery filler, the pile head of the pile is vibrated to form a void between the pile head of the pile and the surrounding ground, Filling the voids with the filler in the form of granular material can be repeated.
[0009]
The horizontal resistance enhancement method piles increases the density of the surrounding soil and filled filler around pile head, can you to enhance the horizontal resistance of piles.
[0010]
In this case, slag having expandability and solidification can be used as the filler.
As the slag having expandability and solidification properties, steelmaking slag (converter slag and / or electric furnace slag (oxidized slag and / or reduced slag) is referred to. In addition, it refers to steelmaking slag that has not lost its expansibility, such as steelmaking slag whose expansibility is adjusted by partially performing an aging treatment.), One or a mixture of two or more kinds of waste incineration slag and sludge slag Can be used.
In addition, slag with expandability and solidification is used alone, as well as steelmaking slag, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud, fly ash, and garbage incineration that have lost their expandability. Industrial waste such as ash, crushed glass, waste gypsum, concrete waste, gypsum, quicklime, cement, crushed stone, earth and sand, clay, and other building materials, artificial materials, and one or more of minerals mixed to expand Can be used that can utilize the expansibility and solidification of the slag.
[0011]
Thereby, after construction, slag having expandability and solidification properties such as filled steelmaking slag absorbs water and expands and solidifies, so that the surrounding ground near the pile head can be consolidated and the density can be further increased. Moreover, since steelmaking slag is a heavy material (unit volume weight is about 20-23 kN / m < ³ >), it can be thrown into the space | gap of a pile and the surrounding ground without clogging on the way. Furthermore, it is possible to effectively use steelmaking slag, which is an industrial waste, and it can contribute to the promotion of the formation of a recycling society.
[0012]
In addition, while installing a vibrator and inclinometer or displacement meter on the pile head of the pile to vibrate the pile head, throwing a filler such as slag into the gap between the pile and the surrounding ground and compacting, inclination or displacement of the stage plus the planned maximum excitation force is Ru can be determined to have reached the required lateral strength with a state has reached a predetermined value.
[0013]
This pile horizontal strength measurement method is to install a vibrator and inclinometer or displacement meter at the pile head during or after construction to vibrate the pile head and slag into the gap between the pile and the surrounding ground. By inserting a filler, etc., and then compacting it, it is determined that the required horizontal strength has been reached when the tilt angle or displacement has reached a predetermined value when the planned maximum excitation force is applied. Without using such a large horizontal loading test device, it is possible to measure the horizontal strength of piles with a simple setting, saving cost and time.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for enhancing horizontal resistance of a pile according to the present invention will be described with reference to the drawings.
[0015]
1 to 2 show an embodiment of a method for enhancing horizontal resistance of a pile according to the present invention.
The method of increasing the horizontal resistance of the pile depends on the construction method, but can be implemented either after the pile is built during construction or after the concrete, cement milk or soil cement is solidified after construction.
This method of increasing the horizontal resistance of the pile is to apply an optimum vibrator 3 to the pile head 2 of the pile 1 based on the design horizontal strength, pile diameter, rigidity, etc. of the pile and the ability of the vibrator (vibration force). By selecting and installing and vibrating the pile head 2 in the horizontal direction (reciprocating motion) or circumferential direction (circular motion), a void 4 is formed around the pile head of the pile 1, and the periphery of the pile and the ground In the gap 4 formed between the slag 1 and the pulverized filler (in this embodiment, powdery slag 5 or sand having expandability and solidification), the entire circumference of the pile 1 from the ground. Are filled continuously or intermittently in a uniform amount.
[0016]
In particular,
1. A vibrator 3 such as an eccentric motor is installed directly on the pile head 2 (FIGS. 1A and 1B).
2. The excitation force of the vibrator 3 is gradually increased stepwise and held for a certain time.
3. The pile head 2 is vibrated in the horizontal direction or the circumferential direction by a vibrator, and a gap 4 is formed between the outer periphery of the pile and the ground (FIG. 1 (c)).
4). The slag 5 (expandable and solidified slag (predetermined molten slag, with a predetermined wind pressure) in the gap 4 between the pile periphery and the ground with or without stopping the vibrator. A fine spherical shape can be obtained by blowing a predetermined air volume (wind crushing))) or sand is continuously or intermittently filled from the ground to the entire circumference of the pile 1 in a uniform amount ( FIG. 1 (d)).
5. Furthermore, the above 2. ~ 4. If necessary, the slag 5 or sand is filled in the gap 4 between the pile periphery and the ground, and slag layers 5a and 5b are formed between the pile periphery and the ground. (FIGS. 2A to 2D).
6). The process ends when the horizontal displacement of the pile 1 is reduced or hardly vibrates.
And the excitation force of a vibrator is applied to the range converted into about 1.3 times the design horizontal proof stress.
[0017]
As the slag 5 as well as the ground and slag compaction around the pile by the vibrator, the swelling and solidification of the slag itself is used to strengthen the pile periphery, so that the expansion of free CaO and free MgO, It is preferable to use a slag containing a solidifying component and having high expansibility and solidification.
As the slag having expandability and solidification property, steelmaking slag (converter slag and / or electric furnace slag (oxidized slag and / or reduced slag) is referred to, and in this case, in particular, an aging treatment (specifically, particularly Although not limited, for example, steelmaking slag that has not been maintained in steam at about 100 ° C for about 100 hours, or has not been subjected to stabilization treatment by leaving it outdoors for a long period of time, or part of the aging treatment Steelmaking slag that does not lose its expansibility, such as steelmaking slag whose expansibility has been adjusted by performing the same, or a mixture of two or more kinds of waste incineration slag and sludge slag can be used.
In addition, slag with expandability and solidification is used alone, as well as steelmaking slag, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud, fly ash, and garbage incineration that have lost their expandability. Industrial waste such as ash, crushed glass, waste gypsum, concrete waste, gypsum, quicklime, cement, crushed stone, earth and sand, clay, and other building materials, artificial materials, and one or more of minerals mixed to expand It is possible to use those that can utilize the expansibility and solidification of slag having properties and solidification, and in particular, it is preferable to use steelmaking slag before aging treatment and slag after aging treatment by adding a strong alkaline substance. .
Here, strong alkali substances include gypsum, granulated slag, blast furnace slag, cement, waste concrete, and the like.
[0018]
In this way, by using slag having expansibility and solidification for the slag 5 to be filled, after construction, the slag having expansibility and solidification such as filled steelmaking slag absorbs water from the surrounding ground and expands and solidifies. By doing this, the surrounding ground near the pile head can be consolidated, and the ground density can be further increased. Steelmaking slag is a material with a heavy specific gravity (unit volume weight is about 20 to 23 kN / m ³ ) and is heavier than the surrounding ground, so it can be put into the gap between the pile and the surrounding ground without clogging in the middle. . Furthermore, it is possible to effectively use steelmaking slag, which is an industrial waste, and it can contribute to the promotion of the formation of a recycling society.
[0019]
Thus, the method for increasing the horizontal resistance of the pile according to the present embodiment is that the pile head 2 of the pile 1 is installed with the vibration generator 3 to vibrate the pile head 2 in the horizontal direction or the circumferential direction. The density of the surrounding ground near the pile head can be increased by compacting the material and the surrounding ground and filling the gap 4 formed around this with a filler such as granular slag.
[0020]
Next, for measuring the horizontal strength of the pile, the pile is constructed by calculating the required horizontal strength required by the pile from the ground boring survey data and the load and structure of the upper structure in advance.
Then, the horizontal tolerance measurement method of pile this, by installing a construction the exciter 3 and inclinometer pile head 2 of pile 1 or displacement meter (not shown), pile head 2 by exciter 3 Oscillate in the horizontal direction (reciprocating motion) or circumferential direction (circular motion), and fill the gap between the pile and surrounding ground, and the pile must be vibrated when the planned maximum excitation force is applied. The state where the displacement amount is reached is the required horizontal strength of the pile 1.
[0021]
And specifically,
1. An exciter 3 such as an eccentric motor and an inclinometer or a displacement meter are installed directly on the pile head 2.
2. The excitation force applied to the vibration generator 3 is gradually increased in several steps, and a certain time is maintained for each step excitation force.
3. The pile head 2 is vibrated in the horizontal direction or the circumferential direction by the vibrator 3, and the excitation force of the vibrator 3 at that time is measured.
4). While filling the gap between the pile and the surrounding ground with slag and other materials to compact the surrounding ground and slag, gradually increase the excitation force of the vibrator 3 and tilt angle with an inclinometer or displacement meter Alternatively, the excitation force is continuously applied for a certain time until the displacement amount becomes small.
Then, when the planned maximum excitation force is applied, it is determined that the required horizontal strength has been reached when the tilt angle or the displacement amount has reached a predetermined value.
And the excitation force of a vibrator is applied to the range of about 1.3 times the design horizontal proof stress.
[0022]
Thus, the method of measuring the horizontal strength of the pile according to the present embodiment is to install the exciter 3 on the pile head 2 of the pile 1 and vibrate the pile head 2 horizontally or circumferentially by the exciter 3. When the excitation force of the exciter reaches the planned maximum excitation force, the required horizontal strength can be obtained when the inclination angle or the displacement amount reaches a predetermined value. This makes it possible to measure the horizontal strength of the pile 1 with a simple setting without using a large-scale horizontal loading test device as in the past, and to confirm the design horizontal strength of the pile 1. And reliability can be improved.
[0023]
Having described the embodiments of the present invention, the horizontal resistance enhancement method of pile of the present invention is not intended to be limited to the description of this embodiment, it can be changed appropriately within a scope not departing from its gist It is.
[0024]
【The invention's effect】
According to the horizontal resistance enhancement method of pile of the present invention to increase the density of the surrounding soil and filled filler around pile head, can you to enhance the horizontal resistance of piles.
Furthermore, since it is not necessary to excavate the vicinity of the pile head to a large diameter, the construction cost of the conventional method for increasing the horizontal resistance of the pile that excavates the vicinity of the pile head to a large diameter increases, and the amount of generated soil increases. Furthermore, the problem of loosening the surrounding ground near the pile head can be solved.
[0025]
In this case, slag having expandability and solidification is used as the filler, and further, as this slag, one or a mixture of steelmaking slag, refuse incineration slag, sludge slag is used, and expandability and solidification. In addition to the use of slag, the steel slag, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud, fly ash, incinerated ash, glass fragments, Industrial waste such as waste gypsum and concrete waste, gypsum, quicklime, cement, crushed stone, earth and sand, building materials such as clay, clay, etc. By using a material that can utilize the expandability and solidification of slag, the slag having expandability and solidification, such as filled steelmaking slag, absorbs water and expands and solidifies after construction. By, compacted around soil near the pile head, it is possible to further enhance a density. Moreover, since steelmaking slag is a heavy material (unit volume weight is about 20-23 kN / m < ³ >), it can be thrown into the space | gap of a pile and surrounding ground, without clogging on the way. Furthermore, it is possible to effectively use steelmaking slag, which is an industrial waste, and it can contribute to the promotion of the formation of a recycling society.
[Brief description of the drawings]
FIG. 1 is a process diagram showing an embodiment (in the case of a pile driving method and a press-in pile method during construction) of a pile horizontal resistance increasing method and a horizontal proof stress measuring method according to the present invention.
FIG. 2 is a process diagram showing a continuous example (in the case of a driving pile method and a press-in pile method during construction) of a method for enhancing horizontal resistance and a method for measuring horizontal strength of a pile according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pile 2 Pile head 3 Exciter 4 Cavity 5 Slag (filler)
5a Slag layer (filler layer)
5b Slag layer (filler layer)

Claims (3)

By vibrating the pile of pile head that built up in the ground in the horizontal direction or the circumferential direction, and pile head of pile, forming a space between the ground of the surrounding, the voids granule-like A method for enhancing the horizontal resistance of a pile characterized by filling with a filler. After filling the gap with powdery filler, the pile head is vibrated to form a gap between the pile head and the surrounding ground. The method for enhancing the horizontal resistance of a pile according to claim 1, wherein filling with a body-like filler is repeated. The method for increasing the horizontal resistance of a pile according to claim 1 or 2, wherein slag having expandability and solidification is used as the filler.

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