JP3158053U - Ground improvement body construction equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a ground improvement body construction apparatus capable of installing an improvement body having a certain strength by sufficiently kneading and stirring a drilling soil and a solidified material during excavation when constructing a ground improvement body. Offer. An apparatus for constructing a ground improvement body for constructing a pile foundation by injecting a solidifying material while excavating the ground, comprising a rod 14 rotatably arranged, and a bit 16 for excavation being a rod. 14, a spiral stirring blade 18 is attached above the bit 16, and cutout portions 20 </ b> A to 20 </ b> C are provided in a part of the stirring blade 18 so that earth and sand during excavation can be moved up and down. By rotating the rod 14, the ground is excavated by the bit 16 at the tip, the solidified material is put into the excavation hole, and the solidified material is kneaded while stirring the excavated soil as the helical stirring blade 18 rotates. In addition, the earth and sand are moved from the notches 20A to 20C of the stirring blade 18 so that a vertical shearing force is applied to the earth and sand. [Selection] Figure 2

Description

  The present invention relates to a ground improvement body construction apparatus, and more particularly to a ground improvement body construction apparatus suitable for construction of a pile foundation of a building constructed on soft ground.

Generally, buildings constructed on soft ground are supported by pile foundations, and soft ground countermeasures for buildings depend on various pile foundations. However, in soft ground, since the burial depth of the piles is deep, when the scale of the building is small, it may be more advantageous in terms of cost to use the ground improvement method than to use the pile foundation.

Conventionally, as such a ground improvement method, a method of constructing a column-shaped improved body by mechanically mixing soil and solidified material with a stirring blade while injecting solidified material such as cement milk during excavation is known. ing. As an example of such a construction method, an invention described in JP 2008-127812 A (Patent Document 1) is known.
FIG. 7 is a view showing a main part of the ground improvement device described in the document. As shown in the figure, the ground improvement device according to the invention described in the publication includes a hollow rod 100 provided with a discharge port for a solidified material, an excavating blade 102 rotating with the hollow rod 100, stirring blades 104 and 106, A co-rotation preventing wing 108 attached rotatably to the hollow rod 100 is provided. When excavating a clay soil having a high adhesive force such as a clay layer, the excavated soil also tries to rotate as the stirring blades 104 and 106 rotate.

On the other hand, since the co-rotation preventing blade 108 described in Patent Document 1 is rotatably attached to the hollow rod 100, the co-rotation preventing blade 108 does not rotate together with the stirring blades 104 and 106, and Since it is in a state of being eroded into the ground during excavation, it does not rotate simultaneously with the excavated soil, and the excavated soil can be divided in the vertical direction during excavation by the co-rotation preventing wing 108 to reduce the mass of the excavated soil. Is possible. As a result, the solidified material and the excavated soil can be more uniformly kneaded and stirred, and the ground improvement work can be performed efficiently.

JP 2008-127812 A

In the invention relating to the “ground improvement device” described in Patent Document 1 described above, when the co-rotation prevention wing 108 is press-fitted into the ground, the excavated soil is digged while being divided in the advancing direction. It is possible to carry out the stirring operation.
However, on the ground with many clay layers and organic matter, it is still difficult to sufficiently mix and agitate the solidified material to the excavated soil, and it is not perfect for using the divided excavated soil as a foundation pile component. .

In other words, when using the surrounding ground as part of the structure of the ground improvement body during excavation, the strength of the pile body that will be the ground improvement body is improved by mixing and stirring the earth and sand sufficiently with the solidified material. Although it is required to ensure, the ground improvement device described in Patent Document 1 contains a large amount of organic matter even if it can be divided in the excavation direction when the components in the ground and the solidified material are kneaded. In a viscous soil such as a peat layer, there is a problem in that it is difficult to uniformly mix with the solidified material because the lump of earth and sand rotates together with the rotation of the stirring blades 104 and 106.

In addition, in the case of the “ground improvement device” described in Patent Document 1, since it is impossible to remove defective soil such as peat, which is inappropriate as the soil constituting the ground improvement body, sufficient strength of the improved body to be constructed is ensured. It was difficult to do, and there was a problem that applicable ground was limited.

The present invention has been proposed to cope with such various circumstances, and when constructing a ground improvement body, the excavated soil generated during excavation and the solidified material are sufficiently mixed and agitated. It aims at providing the construction apparatus of the ground improvement body which can construct | assemble the improvement body of a pile shape or a lapple shape which has the above intensity | strength.
In addition, an object of the present invention is to provide a construction device that can quickly replace defective soil such as viscous soil.

In order to achieve the above object, the device according to claim 1 is a construction device for a ground improvement body for constructing a pile foundation by injecting a solidified material while excavating the ground, and is rotatably arranged. A rod is provided, and a bit for excavation is provided at the lower part of the rod, and a spiral stirring blade is attached to the rod above the bit, and the earth and sand during excavation can be moved up and down on a part of the stirring blade. By rotating the rod, the ground is excavated by a bit at the tip, the solidified material is introduced into the excavation hole, and the excavated soil is removed with the rotation of the helical stirring blade. The mixture is kneaded with the solidified material while stirring, and the earth and sand are moved from the notch of the stirring blade to apply a vertical shearing force to the earth and sand.

In the first aspect, the invention according to the second aspect is characterized in that a single or a plurality of small holes are formed in the stirring blade in addition to or in place of the notch.

As described above, according to the invention described in each claim, in the excavation hole, the excavated soil is mixed with the solidified material while the excavated soil is agitated by the agitating blade, and the earth and sand are moved up and down by moving the notched portion of the agitating blade. The ground improvement body is constructed while applying the shear force in the direction to the earth and sand. Therefore, the excavated soil and the solidified material can be sufficiently agitated and kneaded, and when the ground improvement body is constructed, it is possible to construct a uniform and constant strength improvement body. Further, the co-rotation preventing wing is not required, and the structure of the entire apparatus can be simplified.

It is a perspective view which shows schematic structure of the construction apparatus of the ground improvement body which concerns on 1st Embodiment of this invention. Similarly, it is a principal part perspective view which expands and shows the stirring blade which is the principal part of the construction apparatus of the ground improvement body which concerns on 1st Embodiment of this invention. Similarly, it is explanatory drawing which shows the state in the excavation hole of the stirring blade which is the principal part of the construction apparatus of the ground improvement body which concerns on 1st Embodiment of this invention. Similarly, it is explanatory drawing which shows the construction procedure in the case of constructing a column-shaped pile foundation with the ground improvement body construction apparatus according to the first embodiment of the present invention. Similarly, it is explanatory drawing which shows the outline of an effect | action of a stirring blade, etc. in the case of constructing a column-shaped pile foundation with the ground improvement body construction | assembly apparatus which concerns on 1st Embodiment of this invention. Similarly, it is explanatory drawing which shows the stirring and kneading | mixing condition of excavated soil by the stirring blade which is the principal part of the construction apparatus of the ground improvement body which concerns on 1st Embodiment of this invention. It is the figure which showed the principal part of the conventional ground improvement apparatus.

DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a ground improvement body construction device according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view showing a schematic configuration of a ground improvement body construction apparatus according to a first embodiment of the present invention, and FIG. 2 is a main part of the ground improvement body construction apparatus according to the first embodiment of the present invention. It is a principal part perspective view which expands and shows a certain stirring blade. As shown in FIG. 1, the ground improvement body construction apparatus 10 includes a backhoe 12, a rod 14, a bit 16, a stirring blade 18, and the like.

  A hydraulic motor or an electric motor is mounted on the backhoe 12 as a drive source for rotationally driving the rod 14, and the rod 14 erected vertically on the backhoe 12 can be rotated. In the present embodiment, the backhoe 12 is used as a construction machine that performs excavation work. However, the construction machine is not limited to this, and construction machines such as a construction pillar car, a rough terrain crane, and a small crawler may be used.

As shown in FIG. 2, a bit 16 is installed at the lowermost part of the rod 14, and the bit 16 excavates the ground by rotating the rod 14.
A spiral stirring blade 18 (18A, 18B, 18C,...) Is attached to the rod 14 above the bit 16, and the stirring blade 18 has a notch 20A, 20B, 20C formed in a part thereof. Has been. A small window-like small hole 21 is formed in the stirring blade 18E.

FIG. 3 is an explanatory view showing the state of the stirring blade 18 inserted into the excavation hole 22. As shown in FIG. 3, the stirring blade 18 is formed by attaching a spiral blade to the rod 14. Two helical stirring blades 18A and 18B are continuously formed from the bit 16 and have a shape also serving as a drilling bit. Further, three stirring blades 18C, 18D, and 18E are provided above the bit 16, and a total of five blades are provided. As excavated by these stirring blades 18, the excavated soil can be advanced while being guided upward.

In addition, the notches 20A, 20B, and 20C provided in the stirring blade 18 forcibly move and pass the excavated soil generated during excavation from the notches 20A, 20B, and 20C inside the excavation hole. . As a result, in addition to the rotational force, a vertical shearing force is applied to the excavated soil, and the excavated soil is finely ground as a result of the synergistic effect of both the rotational force and the shearing force. During excavation, a solidified material such as cement milk is supplied into the excavation hole 22 from a slurry mixing plant (not shown), and the solidified material and the excavated soil are mixed and agitated. Is constructed together with excavation work.

Further, it is possible to promote the passage of excavated soil or solidified material upward or downward from the small holes 21 and promote kneading and stirring by shearing force in the same manner as the cutout portions 20A, 20B, and 20C. In the case where the small hole 21 is provided with only one or a plurality of small holes 21 in the stirring blade 18 instead of the notches 20A, 20B, 20C, the single or plural small holes 21 are formed in the notches 20A, 20B. , 20C, there are three possible cases where only a single or a plurality of small holes 21 are provided. When only the small hole 21 is provided, the rigidity of the stirring blade 18 can be ensured.

Next, a ground improvement body construction method using the ground improvement body construction apparatus of the present embodiment configured as described above will be described.
FIG. 4 is an explanatory diagram showing a construction procedure when a column-shaped pile foundation is constructed by the construction device 10 for ground improvement body, FIG. 5 is an explanatory diagram showing an outline of the action of the stirring blade 18 and the like in the excavation hole 22, and FIG. These are explanatory drawings showing the state of stirring and kneading of excavated soil by the stirring blades 18.

  The ground improvement body construction method by the ground improvement body construction apparatus 10 of this embodiment is basically a soil removal process, slurry discharge / digging / upper and lower repeated stirring process (hereinafter abbreviated as “digging stirring process”), It consists of five stages: finishing process, pulling process, and improved body head processing process.

  4 and 5, the horizontal axis represents time, and the vertical axis represents the depth during excavation. As shown in FIG. 4, in the soil removal process (preceding excavation), the top soil is removed from the ground to be constructed, and the ground is improved to the planned height of the ground improvement body by the bit 16 and the stirring blade 18. Remove the earth and sand. And after centering and adjusting the angle of the rod 14, it transfers to an excavation stirring process.

In addition, before the excavation stirring process, a test excavation process for performing a test excavation to a predetermined depth where the ground improvement body is supported and confirming the state of the formation may be added. In this case, for example, when a defective ground including organic matter such as a peat layer and viscous soil is found on the ground in the middle, it is lifted by hooking the earth and sand on the spiral stirring blade 18 of the construction apparatus 10. Then, after removing the defective earth and sand, the process proceeds to the next step, the agitation stirring process. It is possible to construct a ground improvement body of a uniform and uniform material by removing defective soil and the like that inhibit the hydration reaction with cement milk.

In the digging agitation process, the cement milk, which is a solidifying material, is introduced from the head of the digging hole 22 from a slurry mixing plant that is separately installed. Cement milk is added while replenishing a specified amount as needed according to the progress of the agitation process.
During the excavation and agitation process, the state where the excavation hole 22 is filled with cement milk is maintained, and the excavation hole 22 is always filled with cement milk having a low viscosity compared to the case of discharging from the tip of a conventional bit. It becomes possible to hold. Thereby, the improvement of the stirring efficiency of the earth and sand, cement, and milk by the stirring blade 18 can be aimed at.

In the excavation agitation process, as shown in FIG. 4, while rotating the rod 14 forward (clockwise), the vertical agitation and excavation every 1 m are standard, and the vertical movement is repeated several times in the excavation hole 22. Mix and stir the excavated soil and the solidified material. In this process, the top and bottom stirring is repeated three times, and the excavation soil is finely ground as a result of the synergistic effect of both rotational force and shearing force.
Specifically, as shown in FIG. 6 (a), during excavation for lowering the rod 14, the excavated soil is moved upward by the stirring blade 18, and the excavated soil is cut into the excavated soil by the notches 20A, 20B, and 20C. Refine by adding shearing force.

6 (b), when the rod 14 during the kneading operation is raised, the cement milk (solidifying material) and the excavated soil are dropped to the lower end while mixing and shearing, and FIG. As shown in c), when the rod 14 is lowered, the cement milk and the excavated soil are raised in the excavation hole 22 while being mixed and sheared. In short, in the excavation hole 22, by repeating stirring and mixing three times up and down, the excavated soil and the solidified material are sufficiently kneaded, and the sand and clay are mixed thoroughly and uniformly. A ground improvement body is constructed.
In addition, the number of times of up / down repetition is not limited to three, and can be changed as appropriate according to the ground condition. In addition, the water-cement ratio (W / C) of cement milk, which is a solidifying material, is generally in the range of 60% to 100%.

In the improved apparatus 10 of the present embodiment, the worker can visually check the state of the inside of the excavation hole 22 and perform the construction while grasping the mixing / stirring state of the solidified material and the excavating soil, so mixing / stirring is not required. It becomes possible to prevent the situation from becoming sufficient. As a specific standard, it is visually confirmed that there is no lump of approximately 5 cm or more in the improved body slurry. The status of the improved body thus constructed is not required to be confirmed by an inspection jig or the like, and the labor can be reduced.

The management items in the construction of the ground improvement body are the excavation depth, the integrated flow rate (total discharge amount) of the solidified material, and the number of blade cuttings. Among these, the blade cutting frequency (R) is calculated by the following calculation formula.
R = N × n ÷ L 〜 (1)
N: Total number of rotations of the rod (number of rotations x stirring time)
n: Number of blades
L: Improved length

As described above, in this embodiment, the number of blades (n) of the blades is 5 in total, and the above calculation formula when the blade cutting frequency (R) per 1 meter, which is our construction standard, is 350 times ( An example of the stirring time and the number of rotations according to 1) is shown below.
Stirring time = number of blade cutting (R) 350 ÷ 5 sheets = 70 (rotation / min)
Number of revolutions = 30 (rev / min)

In the finishing process, as shown in FIG. 5 and FIG. 6, after repeating up and down from the G level to the tip of the improved body, the process proceeds to the pulling process.
In the pulling process, the rod 14 is pulled out from the excavation hole 22 while being rotated forward or reverse at a pulling speed 2 (m / min). Then, the head height of the improved body is adjusted to be approximately plus or minus 20 mm by the improved body head processing step, and a series of construction work is completed.

As described above, according to the ground improvement body construction apparatus 10 of the present embodiment, the joint rotation prevention wing required in the conventional improvement apparatus is not necessary, and the structure of the entire apparatus can be simplified. It became. Further, the excavated soil generated during excavation and the solidified material can be sufficiently kneaded and stirred, and a uniform and uniform ground improvement body having a certain level of strength and higher can be constructed.

As described above, according to the present invention, in the excavation hole, the excavated soil is mixed with the solidified material while the excavated soil is agitated by the spiral agitating blade, and the earth and sand are moved up and down from the notch portion of the agitating blade. Directional shear force is applied to the earth and sand. Therefore, the excavated soil and the solidified material can be sufficiently agitated and kneaded, and when the ground improvement body is constructed, a uniform and constant strength improvement body can be constructed.

10 Ground improvement body construction equipment
12 Backhoe
14 Rod
16 bits
18 18A 18B 18C 18D 18E Stirring blade
20A 20B 20C Notch
21 small hole
22 Drilling hole

Claims (2)

An apparatus for constructing a ground improvement body that constructs a pile foundation by injecting solidification material while excavating the ground,
It has a rod arranged rotatably, and a drilling bit is provided at the lower part of the rod, and a spiral stirring blade is attached to the rod above the bit, and a part of the stirring blade is used for excavation. A notch that allows the earth and sand to move up and down is provided, and by rotating the rod, the ground is excavated by a bit at the tip, and a solidified material is introduced into the excavation hole, and the spiral stirring blade A ground improvement body characterized in that the excavated soil is agitated with rotation while being kneaded with the solidified material, and the earth and sand are moved from the notch of the agitating blade to apply a vertical shearing force to the earth and sand. Construction equipment. The ground improvement body construction apparatus according to claim 1, wherein a single or a plurality of small holes are formed in the stirring blade in addition to or instead of the notch.

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