JP2003003455A - Compaction method of ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compaction method of the ground capable of firmly compacting the peripheral ground of an excavated hole when the ground is compacted by making use of rotary power of a special auger used for ground improvement. SOLUTION: An excavated soil is pushed against the circumferential wall of the excavated hole 102 by boring the hole in theground 100 as the object of compaction by rotatably driving the special auger 10. At the beginning, the ground at the located around the excavated hole 102 is replaced with the excavated soil to form an excavated soil compressional compaction zone 104. In that time, a natural ground compressional compaction zone 110 is formed in the circumferential side. Then, the special auger 10 is once pulled out from the excavated hole 102 to dump a predetermined amount of improved material into the excavated hole 102, and the improved material is pushed against the circumferential wall of the excavated hole 102 by again boring the hole with the special auger 10. Thereby, the excavated soil compressional compaction zone 104 and the natural ground compressional compaction zone 110 are pushed out to the circumferential side to expand an extent of the natural ground compressional compaction zone 110 and, at the same time, an improved material compressional compaction zone 108 is formed in the inside circumferential side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for compacting the ground, and more particularly to a method for compacting the ground by utilizing the rotational force of a special auger.

[0002]

2. Description of the Related Art The sand compaction pile method has been conventionally known as a typical method for improving sandy ground or cohesive ground, but this method requires a large construction machine, and cobblestone and It is difficult to improve the ground mixed with boulders.

On the other hand, in the pile construction method called the small earth removal method (Alex construction method), the ground is compacted by utilizing the rotating force of the special auger during the pre-excavation performed before the pile is built. Therefore, it can be diverted to ground improvement. In this small earth removal method, advance excavation is performed in the process as shown in FIG.

That is, as shown in FIG. 1 (a), the special auger 10 is driven to rotate on the ground 100 to be compacted, and the drilling is performed in a conical shape. The resulting excavated soil is pressed against the peripheral wall of the excavated hole 102, thereby forming the excavated soil compression compaction zone (compression compaction zone by the excavated soil) 104 around the excavation hole 102. At that time, the ground initially located around the excavation hole 102 is compressed so as to be spread to the outer peripheral side, so that the outer ground side of the excavated soil compression compaction zone 104 is compressed by the raw ground compression compaction zone (Compression compaction zone by the ground)
110 is formed. Thereafter, as shown in FIG. 2B, by pulling out the special auger 10 from the excavation hole 102 while discharging the grout material 114 such as cement milk and soil cement from the tip of the special auger 10,
As shown in FIG. 3C, the drill hole 102 is formed in the grout material 1
Fill with 14.

If the ground is improved by compacting the ground around the excavation hole by utilizing the rotating force of the special auger, the construction machine can be made compact and the cobblestone and It is possible to improve the ground even if the ground contains boulders.

[0006]

However, the small-discharging method is not a method for compacting the ground itself,
H steel, PHC in the drill hole filled with grout material
It is a construction method for the purpose of building piles, etc. and constructing support piles and mountain retaining walls, and the compaction of the surrounding ground that is performed during the preceding excavation is to prevent collapse of the excavation hole. Is.

[0007] Therefore, simply diverting the small-discharging method to ground improvement only forms the excavated soil compression compaction zone and the original ground compression compaction zone around the excavation hole, and further Since no compaction effect can be expected,
There is a problem that ground improvement cannot be performed effectively.

The present invention has been made in view of the above circumstances, and in the case where the ground is compacted by utilizing the rotational force of a special auger for ground improvement, the periphery of the excavation hole An object of the present invention is to provide a method for compacting the ground that can firmly compact the ground.

[0009]

SUMMARY OF THE INVENTION The present invention is to achieve the above object by devising a method of using a special auger.

That is, the method for compacting the ground according to the present invention uses a special auger configured to press the excavated soil generated by the drilling against the peripheral wall of the drilling hole, and to rotate the special auger. A method of compacting the ground using the method, wherein the special auger is rotationally driven to make a hole in the ground to be compacted, and the excavated soil is pressed against the peripheral wall of the excavated hole. Then, the special auger is temporarily pulled up from the drill hole, a predetermined amount of the modifying material is put into the drill hole, and then the special auger is rotationally driven again with respect to the modifying material put into the drill hole. By performing drilling, the improved material is pressed against the peripheral wall of the drilled hole,
It is characterized by that.

The above-mentioned "special auger" is not particularly limited in its specific constitution as long as it is constructed so as to press the excavated soil generated by the drilling against the peripheral wall of the drilling hole.

The "improving material" is not particularly limited in its kind as long as the improving material is a material that contributes to ground improvement by being pressed against the peripheral wall of the excavation hole.
For example, sand, crushed stone, recycled crushed stone, slag,
Coal ash, ground improvement materials such as cement-based stabilizers, fluidized soil, etc. can be used. Also, the amount of the "improvement material" to be added may be appropriately set according to the required ground improvement rate, improvement strength, and the like.

[0013]

As described above, the method of compacting the ground according to the present invention uses the special auger configured to press the excavated soil generated by the drilling against the peripheral wall of the drilling hole. , It is designed to compact the ground by using the rotating force of this special auger. As a concrete construction method, the special auger is rotationally driven and drilled for the ground to be compacted. By pressing the excavated soil against the peripheral wall of the excavation hole, then temporarily pulling up the special auger from this excavation hole and charging a predetermined amount of the improvement material into the excavation hole, then,
Since the special auger is rotationally driven to perform the drilling again on the improved material put into the drilled hole, the modified material is pressed against the peripheral wall of the drilled hole. Can be obtained.

That is, by compacting the ground by the above-mentioned construction method, an excavated soil compression compaction zone is formed around the excavation hole, in which the excavated soil is compressed, and the original ground is provided on the outer peripheral side thereof. Since the original ground compression compaction zone is formed by compressing, the improvement material compression compaction zone formed by the improvement material being compressed is formed on the inner peripheral side of the excavated soil compression compaction zone. The ground around the excavation hole can be firmly compacted as a multi-cylindrical compression compaction zone including the improvement material compression compaction zone.

As described above, according to the present invention, when the ground is compacted by using the rotating force of the special auger for the ground improvement, the ground around the excavation hole can be firmly compacted. . And by this, the ground improvement effect can be enhanced.

Further, in the present invention, since the improvement material compression compaction zone can be made to function as a cylindrical drainage pile such as a sand pile, when the ground to be compacted is a viscous ground, consolidation is promoted. Increased strength of cohesive soil due to
It is possible to increase the strength of the composite ground composed of the improved material and the cohesive ground. Due to these effects, it is possible to adopt a plurality of ground improvement methods such as improvement of stability against slope slip, increase of bearing capacity of the ground, prevention of liquefaction and the like.

In the present invention, since the ground is improved by compacting the ground by utilizing the rotating force of the special auger, the construction machine can be constructed compactly and the boulders and boulders are mixed. The ground can be improved even on the ground.

In the above structure, the improvement material may be introduced and the special auger may be rotationally driven again only once, but it may be repeated a plurality of times.
By doing so, the ground around the excavation hole can be configured by the compression compaction zone including the improvement material compression compaction zone formed in multiple layers, so that the ground improvement effect can be further enhanced.

In the above structure, after the improved material is pressed against the peripheral wall of the drill hole, the special auger is pulled up from the drill hole while discharging grout materials such as cement milk and soil cement from the tip of the special auger. Thus, the excavation hole may be filled with the grout material to complete the construction, but instead of this, the following construction may be additionally performed.

That is, after the improvement material is pressed against the peripheral wall of the excavation hole, the special auger is pulled up from the excavation hole and the predetermined amount of the improvement material is again injected into the excavation hole. A small special auger having a diameter smaller than that of the special auger is rotationally driven against the material to make a hole, and the improved material is pressed against the peripheral wall of the drilling hole, and then cement milk or soil is passed from the tip of the small special auger. The small special auger may be pulled up from the excavation hole while discharging grout material such as cement.

By additionally performing such a construction, the improvement material compression compaction zone can be additionally formed around the excavation hole, so that the ground around the excavation hole is compacted more firmly. You can

[0022]

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

FIGS. 1, 2 and 3 are process diagrams showing a method for compacting the ground according to an embodiment of the present invention.
Is a special auger 10 used for this ground compaction method.
It is a side view which shows.

First, the structure of the special auger 10 will be described.

As shown in FIG. 4, this special auger 10 is used.
Is a shaft main body 12 extending in the vertical axis Ax direction, an excavation head 14 attached to a lower end of the shaft main body 12, and a plurality of screw blades intermittently provided on the peripheral surface of the shaft main body 12 in a spiral arrangement. 16 and these screw blades 16
And a plurality of consolidation blades 18 provided in a predetermined arrangement at the position of the outer peripheral edge of the. Each of the compression blades 18 is formed in a curved shape along a cylindrical surface surrounding the vertical axis Ax, and is provided so as to connect the outer peripheral edge portions of the two screw blades 16 adjacent to each other in the vertical axis Ax direction. There is.

The special auger 10 is connected and supported at the upper end 12a of the shaft body 12 via a chuck 20 to a rotary drive unit 22 of a construction machine (not shown).
The special auger 10 is rotationally driven by the rotary drive unit 22 as shown by an arrow A to perform drilling in a conical manner, and excavated soil generated by the drilling is compressed by a plurality of consolidation blades 18. As shown by the arrow B, it is configured to be pressed against the peripheral wall of the excavation hole. In the present embodiment, the rotational force of the special auger 10 is used to compact the ground.

Next, a method of compacting the ground according to this embodiment will be described.

First, as shown in FIG. 1 (a), the special auger 10 is rotationally driven on the ground 100 to be compacted to form a conical shape. The excavated soil thus generated is pressed against the peripheral wall of the excavation hole 102. As a result, the excavated soil compression and compaction zone (excavated soil compression and compaction zone) 10 is formed around the excavation hole 102.
4 is formed. This excavated soil compression compaction zone 104
Ground (original ground) originally located around the drilled hole 102
Is formed so as to be replaced with excavated soil, this raw ground is compressed by being spread outward by the excavated soil, whereby the raw ground compression compaction zone (compression compaction zone by the raw soil) 110 is formed. It is formed on the outer peripheral side of the excavated soil compression compaction zone 104. At the time of drilling,
Depending on the soil condition, the peripheral wall may be stabilized by using muddy water or fresh water.

Then, as shown in FIG.
After the special auger 10 is temporarily pulled up from 02, as shown in FIG. 2C, a predetermined amount of the improvement material 106 is put into the excavation hole 102 (the amount at which the excavation hole 102 is substantially full).

After that, as shown in FIG. 2D, the special auger 10 is rotationally driven to perform drilling again on the modifying material 106 put into the drilling hole 102 to drill the modifying material 106. It is pressed against the peripheral wall of the hole 102. And thereby, while pushing out the excavated soil compression compaction zone 104 and the raw ground compression compaction zone 110 already formed around the excavation hole 102 to the outer peripheral side, and expanding the range of the raw ground compression compaction zone 110, A cylindrical improvement material compression compaction zone (compression compaction zone by the improvement material) 108 is formed on the inner peripheral side thereof.

Next, as shown in FIG. 1E, the excavation hole 1
After pulling up the special auger 10 from 02, as shown in FIG. 2F, the improvement material 106 is again charged into the drill hole 102 by a predetermined amount (the amount by which the drill hole 102 is almost full).

Then, as shown in FIG. 3 (g),
A small special auger (a special auger having a structure similar to that of the special auger 10 but having a diameter smaller than the special auger 10) 30 is rotationally driven and drilled for the improvement material 106 put in the drill hole 102. As a result, the improvement material 106 is pressed against the peripheral wall of the excavation hole 116 (a small-diameter excavation hole that is newly formed concentrically with the excavation hole 102). As a result, the improvement material compression compaction zone 108, the excavated soil compression compaction zone 104, and the ground foundation compression compaction zone 110, which have already been formed around the excavation hole 116, are extruded to the outer peripheral side to push out the ground foundation compression compaction zone. The area 110 is expanded, and a cylindrical improvement material compression compaction zone 11 is provided on the inner peripheral side thereof.
Form 2.

Thereafter, as shown in FIG. 3H, the small special auger 30 is discharged from the tip of the small special auger 30 while the grout material 114 such as cement milk and soil cement is discharged from the drilled hole 116 having a small diameter. By pulling up, as shown in (i) of the figure, the excavation hole 116 is filled with the grout material 114, whereby the compaction construction of the ground is completed.

FIG. 5 is a plan view showing a state in which the soil improvement by the soil compaction method according to the present embodiment is sequentially performed on a plurality of locations of the soil 100.

As shown in the figure, the compaction with respect to the ground 100 is carried out in a grid-like arrangement at a predetermined interval. Then, at each compaction execution location in the ground 100, the improvement material compression compaction zone 112 in which the improvement material 106 is compressed around the columnar portion filled with the grout material 114 and the improvement material 106 are compressed. The improved material compaction compaction zone 108 and the excavated soil compaction compaction zone 104 formed by compressing the excavated soil are concentrically arranged. The original ground compression compaction zone 110 formed by compressing the existing ground is arranged.

As a result, a compression compaction zone 118 defined by the range surrounded by the outer contour line of the original ground compression compaction zone 110 is formed at each compaction site. Then, the ground within the envelope range of the contour line on the outer peripheral side of the compression compaction zone 118 formed at each of these compaction construction sites constitutes the ground improvement section 120.

The size of the compression compaction zone 118 formed at each compaction construction site varies depending on the soil condition of the ground 100, the type of the improving material 106, etc. It is sufficient to set the construction interval of the solidification construction site. Further, the construction interval of each compaction construction site may be appropriately set according to the required ground improvement rate, improvement strength, and the like.

FIG. 6 is a diagram showing an application example of ground improvement by the ground compaction method according to the present embodiment.

FIG. 3A shows the embankment foundation ground 202 by applying the above-mentioned ground improvement to the embankment foundation ground 202 of the expressway consisting of loose sandy ground (or loose gravel ground).
It is intended to stabilize the slope of the newly constructed road embankment 204 by reinforcing the. In the same figure (b), by applying the above-mentioned ground improvement to the railway foundation ground 212 made of loose sandy ground (or loose gravel ground), vibration resistance reinforcement of the existing railway embankment 214 (measures to prevent liquefaction and lateral flow). ). In the same figure (c), by applying the above-mentioned ground improvement to the soft and viscous ground 222, the strength is increased by the consolidation promotion and the strength as a composite ground composed of the improved material and the cohesive ground is increased, and the soft and viscous ground is increased. This is intended to improve the land block 222.

As described in detail above, in the method for compacting soil according to the present embodiment, excavated soil is excavated by rotating the special auger 10 to rotate the special auger 10 on the soil 100 to be compacted. It is pressed against the peripheral wall of the excavation hole 102, then the special auger 10 is once pulled up from this excavation hole 102 and a predetermined amount of the improvement material 106 is put into the excavation hole 102, and thereafter,
The special auger 10 is rotationally driven with respect to the improving material 106 put in the drilled hole 102 to perform the drilling again, so that the modifying material 106 is pressed against the peripheral wall of the drilled hole 102. Such an effect can be obtained.

That is, by performing the soil compaction by the above-mentioned construction method, the excavated soil compaction compaction zone 104 is formed around the excavation hole 102, and the raw soil compaction compaction zone 110 is formed on the outer peripheral side thereof. Further, since the improved material compression compaction zone 108 is formed on the inner peripheral side of the excavated soil compression compaction zone 104, the ground around the excavation hole 102 is improved material compaction compaction zone 108.
Can be firmly compacted as a multi-cylindrical compression compaction zone 118 containing.

In addition, in the embodiment, after the improvement material compression compaction zone 108 is formed, the special auger 10 is pulled up from the excavation hole 102 and the improvement material 10 is again inserted into the excavation hole 102.
6 is introduced in a predetermined amount, and the small special auger 30 is rotatably driven with respect to the improving material 106 put in the drilling hole 102 to perform drilling, so that the modifying material 106 is newly drilled 11
Since the small special auger 30 is pulled up from the excavation hole 116 while the grout material 114 is discharged from the tip of the small special auger 30 after being pressed against the peripheral wall 6, the innermost peripheral portion around the excavation hole 102 is formed. Further, the improvement material compression compaction zone 112 can be additionally formed, so that the ground around the excavation hole 116 can be more firmly compacted.

As described above, according to the embodiment, the drill hole 10 is formed.
The surrounding ground of No. 2 is improved compaction compaction zone 108, 112
Can be firmly compacted as a multi-cylindrical compression compaction zone 118 including, and thus the ground improvement effect can be sufficiently enhanced.

In addition, in the embodiment, since the improvement material compression compaction zones 108 and 112 can function as cylindrical drainage piles, the drainage function is ensured and the ground 10 is secured.
The intensity of 0 can be increased. As a result, it is possible to obtain a plurality of ground improvement effects such as improvement of stability against slope slip, increase of ground support force, and prevention of liquefaction.

In this embodiment, when the ground is improved, the drilling hole 10 is utilized by utilizing the rotating force of the special auger 10.
Since the surrounding ground of No. 2 is compacted, the construction machine can be configured compactly, which makes it possible to perform construction even in a narrow place or on the ground where a large ground pressure cannot be secured. Become.

Further, by adopting the method of compacting the ground utilizing the rotating force of the special auger 10 as described above, it is possible to improve the ground even if the ground contains boulders or boulders. On the other hand, even when the ground to be compacted is a viscous soil, since the improvement material compression compaction zone 108 formed by the above-mentioned construction method functions as a cylindrical drainage pile, the viscosity due to the acceleration of the consolidation of the ground is increased. It is possible to increase the strength of the ground and increase the strength of the composite ground composed of the improved material and the cohesive ground.

In the present embodiment, the case where the improvement material compression compaction zone 108 formed by the special auger 10 is a single layer has been described, but the improvement material 106 charging step and the special auger 10 rotational driving are repeated. A plurality of layers of the improvement material compression compaction zone 108 may be formed by repeating the drilling step (steps of FIGS. 1C to 2E). By doing this, the drill hole 1
The surrounding ground of 02 is a multi-layer improvement material compression compaction zone 108
It is possible to configure the compaction and compaction zone including, and thereby the ground improvement effect can be further enhanced.

In compacting the ground, instead of performing all the steps of FIGS. 1 to 3 as in the present embodiment, the steps of FIGS. In the step e), when the special auger 10 is pulled up from the drill hole 102, the grout material is discharged from the tip of the special auger 10 so that the drill hole 102 is filled with the grout material and the construction is completed. Good. Even in this case, the ground around the excavation hole 102 can be compacted to some extent as a multiple cylindrical compression compaction zone including the improvement material compression compaction zone 108.

[Brief description of drawings]

FIG. 1 is a process diagram (1) showing a method for compacting ground according to an embodiment of the present invention.

FIG. 2 is a process diagram (part 2) showing the method for compacting the ground according to the above embodiment.

FIG. 3 is a process diagram (3) showing the method for compacting the ground according to the above embodiment.

FIG. 4 is a side view showing a special auger used in the above embodiment.

FIG. 5 is a plan view showing a state in which ground improvement by the soil compaction method according to the above-described embodiment is sequentially performed on a plurality of locations on the ground.

FIG. 6 is a diagram showing an application example of soil improvement by the soil compaction method according to the embodiment.

FIG. 7 is a view similar to FIG. 1 showing a conventional example.

[Explanation of symbols]

10 Special auger 12-axis body 12a upper end 14 drilling head 16 screw blades 18 Consolidation wings 20 chuck 22 Rotational drive 30 Small special auger 100 ground 102,116 drill holes 104 Excavated soil compression compaction zone 106 Improved material 108, 112 Improved material compression compaction zone 110 Ground compression zone 114 grout 118 compression compaction zone 120 Ground Improvement Department 202 Embankment foundation ground 204 Embankment of new road 212 Railway foundation ground 214 Existing railway embankment 222 Soft cohesive ground Ax vertical axis

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Claims (2)

[Claims] 1. A method of compacting the ground by using a rotating force of the special auger configured to press the excavated soil generated by the drilling against the peripheral wall of the drilling hole. By rotating the special auger to make a hole in the ground to be compacted, the excavated soil is pressed against the peripheral wall of the excavation hole, and then the special auger is once removed from the excavation hole. By pulling up, a predetermined amount of the improving material is put into the drilled hole, then, with respect to the improved material put into the drilled hole, the special auger is rotationally driven to perform drilling again,
A method for compacting the ground, comprising pressing the improved material against a peripheral wall of the excavation hole. 2. The above-mentioned improvement material is pressed against the peripheral wall of the above-mentioned excavation hole, the above-mentioned special auger is pulled up from this excavation hole, a prescribed amount of the improvement material is again injected into this excavation hole, and then this excavation hole A small special auger having a diameter smaller than that of the special auger is rotationally driven with respect to the introduced improved material to make a hole, so that the improved material is pressed against the peripheral wall of the excavation hole and then the small special auger. Pulling out the small special auger from the drilling hole while discharging grout material from the tip of
The method for compacting the ground according to claim 1, wherein