JP4072968B2 - Columnar pile building device and columnar pile building method - Google Patents

Description

  The present invention relates to a columnar pile building device and a columnar pile building method that are excellent in dispersibility of a solidifying material slurry in an original ground soil when building a columnar pile serving as a foundation of a structure.

  When building a building, a retaining wall, a workpiece or the like on the ground, a large number of columnar piles solidified with cement slurry may be created in the ground as the foundation of these structures. Such a columnar pile has, for example, a diameter of 600 mm, a maximum improved depth of about 8 m, and a uniaxial compressive strength close to that of a concrete pile, so a solidified pile created by a deep mixing treatment method for the purpose of ground improvement in the civil engineering field. Is different. Conventionally, as an apparatus for creating a large number of these columnar piles in the ground, a columnar pile building apparatus shown in FIG. 5 is known.

  This columnar pile forming apparatus 100 is provided with a drilling blade 102 having both blades on the tip side of a hollow stirring shaft 101, and on the side of the stirring shaft that is 90 degrees away from the root 106 of the drilling blade 102 at the center of the shaft, A solidified material slurry discharge port 103 communicating with the supply means is provided. Reference numeral 104 is a stirring blade, and 105 is a co-rotation prevention plate. When a columnar pile is formed on the ground using this columnar pile forming apparatus 100, the solidified material slurry discharge port is inserted while rotating the agitation shaft in accordance with the end of the hollow agitation shaft aligned with the core of the columnar pile to be constructed. The solidified material slurry is discharged from 103, and by rotating the stirring blade 104, a columnar pile is formed while being stirred and mixed with the original ground soil.

  However, in the columnar pile building method using the columnar pile building device 100, the place where the solidified material slurry is discharged is between the stirring shaft and the raw ground soil, and the solidified material slurry discharge port 103 is the excavating blade 102. Since it is also a position 90 degrees away from the base of the shaft at the center of the axis, the discharged solidifying material slurry is not dispersed in the form of a strip in a planar manner, and is discharged in a spot manner. For this reason, the solidified material slurry is diffused in the horizontal direction by the stirring blades 104 above the solidified material slurry discharge port 103 and mixed and stirred with the ground soil. As described above, in the conventional columnar pile forming method, in order to obtain a uniform and predetermined strength, one step of penetration and extraction is usually performed in two steps. For this reason, it has been desired to develop a columnar pile building method having a uniform and predetermined strength and a columnar pile building device for carrying out the method in one step of penetration and drawing.

  Therefore, an object of the present invention is to create a columnar pile having a uniform and predetermined strength in one step of penetration and extraction, in which the discharged solidified slurry can be immediately dispersed in a flat band shape in the original ground. It is providing the columnar pile creation apparatus and columnar pile creation method which can do.

  In such a situation, as a result of intensive studies, the present inventor has found a guide plate having a length and a predetermined height from the side of the hollow stirring shaft to the tip of the excavating blade directly above or directly below at least one of the excavating blades. If the solidified material slurry discharge port communicating with the ground solidified material slurry supply means is provided on the back side of the guide plate and on the stirring shaft, the back side of the guide plate becomes hollow due to the rotation of the stirring shaft. Since the ground becomes weak in dynamic pressure, the discharged solidified material slurry is dispersed in a planar shape in a flat manner and can be dispersed widely and uniformly in the horizontal direction as the stirring shaft rotates, leading to the completion of the present invention. It was.

That is, according to the present invention , a length and a predetermined height from the side surface of the hollow stirring shaft to the tip of the drilling blade are directly above at least one blade of the drilling blade having both blades attached to the tip side of the hollow stirring shaft. And a solid plate slurry discharge port which is provided with a vertical plate or a guide plate which is a forwardly inclined plate, and which communicates with the ground solid material slurry supply means on the back side of the guide plate and the stirring shaft. Using a columnar pile building device provided with a hollow stirrer, rotate the stirrer shaft so that the tip of the hollow stirrer shaft aligns with the core of the columnar pile to be constructed, and discharge the solidified material slurry from the solidified material slurry outlet during penetration. While rotating the stirring blade, and simultaneously discharging the solidified slurry into the belt shape on the excavation blade, the columnar pile is formed while stirring and mixing with the ground soil. It provides a pile building method .

Further, the present invention provides a drilling blade having both blades on the tip side of the hollow stirring shaft,
A guide plate which is a vertical plate or an inclined plate which has a predetermined height and a length from the side surface of the hollow stirring shaft to the tip of the excavating blade immediately above at least one of the excavating blades. Established
Provided on the back side of the guide plate and on the stirring shaft is a solidified material slurry discharge port communicating with the ground solidified material slurry supply means,
The excavating blade has a portion for planarly dispersing the solidified material slurry on the excavating blade at the same time as discharging.
A columnar pile building device for carrying out the columnar pile building method according to claim 1 is provided.

  According to the present invention, the discharged solidifying material slurry can be immediately dispersed in a flat band shape in the original ground, and a columnar pile having a uniform and predetermined strength can be created in one step of penetration and extraction. . For this reason, the time for carrying out the construction method can be substantially halved compared with the conventional construction method, and the construction period can be shortened.

  Next, a columnar pile forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a part of a columnar pile forming apparatus according to the present embodiment, FIG. 2 is an enlarged schematic perspective view of the vicinity of the excavating blade of FIG. 1, and FIG. 3 is a state in which solidified material slurry is discharged and diffused in a planar shape. The schematic plan view which shows is shown, respectively. In addition, in this specification, a back surface means the opposite side of a rotation direction. In FIG. 2 and FIG. 4, the excavation blade 2 is shown as a horizontal blade with a rectangular cross section for the sake of simplicity, but in practice, the excavation efficiency is enhanced by being inclined downward in the rotation direction.

  The columnar pile forming device 10 is provided with a drilling blade 2 having both blades 2 a and 2 b on the tip side of the hollow stirring shaft 1, and the drilling blade 2 from the side surface of the hollow stirring shaft 1 directly above one blade 2 a of the drilling blade 2. A guide plate 8 having a length reaching the tip and a predetermined height h is erected, and a solidified material slurry discharge port communicating with ground solid material slurry supply means (not shown) on the back side of the guide plate 8 and the stirring shaft 1. 7 is provided.

  Further, the stirring shaft 1 is provided with a co-rotation prevention plate 5, a stirring blade 4 having both blades, a co-rotation prevention plate 5, and a stirring blade 4 having both blades in that order on the upper side of the excavation blade 2. ing. The attachment angle α with respect to the traveling direction of the stirring blade 4 is appropriately determined from 20 to 90 degrees, but is 20 degrees in this example. The co-rotation prevention plate 5 does not rotate in synchronism with the agitation shaft, but is formed by mixing the raw ground soil and the solidified material, and co-rotates between the upper and lower agitating blades 4 and 4 to prevent mixing and agitation. In this case, the stirring of each of the upper and lower stirring blades 4 and 4 is cut off.

  In the columnar pile forming apparatus 10, the guide plate 8 is a long plate-like object, one end in the longitudinal direction is joined to the stirring shaft 1, and the lower end in the short direction (vertical direction) is one of the excavating blades 2a. It is joined to the upper surface. The length of the guide plate 8 in the longitudinal direction is the same as the length of one of the excavating blades 2a, and the cavity portion corresponding to the length of the excavating blade 2a or the portion 9 (hereinafter simply referred to as “cavity”). It is preferable in that it can form a columnar pile having a uniform strength over the entire radial direction. Further, the height h in the short direction of the guide plate 8 is appropriately determined depending on the discharge amount of the solidifying material slurry, but is larger than the diameter of the solidifying material slurry discharge port 7. It is about 80 mm. If the height h in the short direction of the guide plate 8 is too low, the design amount of the solidified material slurry cannot be put into the cavity 9, and if the height h is too high, the excavation resistance increases, which is not preferable. .

  The installation form of the guide plate 8 is not particularly limited as long as the hollow portion 9 is formed on the back side of the guide plate 8 by the rotation of the stirring shaft 1. An inclined plate having a downward slope may be used. As shown in FIG. 4, the guide plate 8 a may have an inverted L-shaped cross section including a vertical plate 81 and a top plate 82 extending rearward from the upper end of the vertical plate 81. According to the guide plate 8a, the cavity 9 can be reliably formed on the back side of the guide plate 8a. Similarly, in the guide plate 8a, the vertical plate 81 may be slightly inclined forward and may be inclined in the same manner while maintaining the inverted L-shaped cross section.

  The guide plates 8 and 8a may be formed on both blades of the excavation blade (not shown). That is, for example, in FIG. 2, a second guide plate is further provided immediately above the other blade 2b extending in the direction opposite to the one blade 2a, and the solidification material is provided on the back side of the second guide plate and on the stirring shaft. A second solidified material slurry discharge port may be provided that faces in the opposite direction to the slurry discharge port 7. Thus, providing the solidifying material slurry discharge ports on both sides of the stirring shaft is preferable in that, for example, even if one solidifying material slurry discharge port 7 is clogged, the construction can be continued at the other solidifying material slurry discharge port.

  In the columnar pile forming apparatus 10 in the present embodiment shown in FIGS. 1 to 4, the installation location of the guide plates 8 and 8 a is directly above the excavating blades 2 and 2 a, but in the present invention, it is limited to this. Instead, it may be directly under the excavating blades 2, 2a. In this case, similarly, on the back side of the guide plate and on the stirring shaft, a solidified material slurry discharge port communicating with the solidified material slurry supply means on the ground is provided. Similarly, the guide plate directly below the excavating blades 2 and 2a may be installed on one excavating blade or both excavating blades, and may be provided with a guide plate directly above the excavating blades 2 and 2a.

  The solidifying material slurry discharge port 7 is attached to the stirring shaft 1 on the back side of the guide plate 8 and communicates with a known solidifying material slurry supply means on the ground. The communication method between the solidified material slurry discharge port 7 and the solidified material slurry supply means is not particularly limited, and a hole formed in the side surface of the stirring shaft 1 communicates with a hollow portion of the stirring shaft, and the hollow portion is connected to the solidified material. A method in which the slurry flows, or a solidifying material slurry supply / supply pipe is disposed in the hollow portion of the stirring shaft, one end of the solidifying material slurry supply / supply pipe is fitted into the hole of the stirring shaft 1, and the other end is used as the solidifying material slurry supplying means. The method of connection etc. are mentioned. In addition, it is preferable to provide a known check valve at the solidifying material slurry discharge port 7 in that the raw ground soil does not flow back into the stirring shaft.

  The solidifying material slurry is not particularly limited, and a known cement slurry can be used. Moreover, as a solidification material slurry supply means, for example, a solidification material slurry storage tank and a liquid feed pump are provided. In the columnar pile forming apparatus 10 of the present invention, solidification material slurry is supplied at a lower pressure than in the conventional method. can do.

  Next, a method for creating a columnar pile using the columnar pile forming apparatus 10 will be described. The tip of the hollow stirring shaft 1 of the columnar pile forming apparatus 10 is rotated in accordance with the core of the columnar pile to be constructed, and the stirring blade is discharged while solidified slurry is discharged from the solidified material slurry discharge port 7 during penetration. Rotate No. 4 and create a columnar pile while mixing with the ground soil.

  According to this columnar pile forming method, as shown in FIG. 3, the back side of the guide plate 8 becomes hollow or becomes a ground with low dynamic pressure due to the rotation of the stirring shaft 1 (in the direction of the arrow X). The solidified material slurry is dispersed in a flat band simultaneously with the discharge, and can be widely and uniformly dispersed in the horizontal direction as the stirring shaft 1 rotates. In FIG. 3, the portion extending in the radial direction with the width indicated by the symbol Y indicates a strip-like dispersion state, and the black-filled portion of the upper semicircular portion indicates a state in which the portion is spread widely and uniformly in the horizontal direction. Thereafter, the solidified material slurry uniformly and widely dispersed is further stirred and mixed with the raw ground by the stirring blade 4. And, by pulling out the stirring shaft, the raw ground soil and the solidified material slurry are further mixed, so that a high-quality columnar pile can be formed in one step of penetration and drawing.

The pile arrangement form of the columnar pile obtained by this columnar pile creation method is not particularly limited, and examples thereof include a contact circle arrangement form and a wrap arrangement form. Moreover, as a uniaxial compressive strength of columnar pile, it is 1-5MN / m < ² > normally, 0.1-0.5MN / m < ² > solidification process obtained by the deep mixed processing method implemented by the ground improvement of the civil engineering field It is very different from the pile. Moreover, as a use of a columnar pile, foundations, such as a building, a retaining wall, and a workpiece, are mentioned.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

It is the apparatus form shown in FIG.1 and FIG.2, and 1 process of penetration and drawing | extracting was performed on the following construction conditions using the columnar pile production apparatus of the following specification. The uniaxial compressive strength of the obtained columnar pile was measured. Measurements were made at arbitrary several locations. As a result, every part was 3MN / m ² and a uniform and high strength columnar pile was obtained.

(Column pile construction equipment and construction conditions)
・ Number of stirring shafts and number of revolutions: Single shaft, around 30 times / minute ・ Stirring method: One-way stirring with horizontal stirring blades ・ Spinning prevention mechanism; Installed between excavation blade and lower stirring blade and between stirring blades 2 Stage mechanism / Number of stirring blades: Two blades, upper and lower, two blades, one blade excavation blade, blade cutting frequency: around 720 times, improved working diameter and depth; diameter 600 mm, depth 5000 mm
・ Guide plate; the length is the same as the length of one of the excavating blades, and the height is 50 mm
・ Penetration and drawing speed: 0.5 m / min ・ Solidification material: Solidification material input 350 kg / cm ³ , Water / cement 60%
・ Volume of solidified material discharged per rotation: about 1.5 liters

Note that except for omitting the installation of the guide plate, in the construction using the conventional columnar pile reclamation device is the same conditions as in Example 1, to obtain a columnar pile uniaxial compressive strength 3MN / m ² is 2 steps It was necessary to carry out. Thus, according to the columnar pile construction method of the present invention, a high-quality columnar pile can be constructed in half the conventional construction period.

It is a partial front view of the columnar pile building apparatus in this Embodiment. It is the schematic perspective view which expanded the excavation blade vicinity of FIG. It is a schematic plan view which shows the state which solidification material slurry discharges and spread | diffuses planarly. It is the schematic schematic which expanded the excavation blade vicinity of the columnar pile production apparatus in other embodiment. It is a front view of the front-end | tip part of the conventional columnar pile building apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow stirring shaft 2, 102 Excavation wing | blade which has both wing | blades 2a One wing | blade 2b The other wing | blade 4,104 Stirring wing 5,105 Corotation prevention board 7,103 Solidification material slurry discharge port 8,8a Guide board 10,10a, 100 Columnar pile creation device 21 Drilling bit

Claims (2)

Immediately above the at least one wing of the drilling blade having two wings that are attached to the distal end side of the hollow stirring shaft, it has a length and a predetermined height extending from the side surface of the hollow stirring shaft to the tip of該掘Kezutsubasa and vertical A columnar pile provided with a guide plate which is a plate or an inclined plate which is inclined downward in the front, and which is provided with a solidifying material slurry discharge port which communicates with the ground solidifying material slurry supply means on the back side of the guide plate and on the stirring shaft The tip of the hollow stirring shaft is rotated in accordance with the core of the pillar pile to be constructed, and the stirring blade is discharged while the solidifying material slurry is discharged from the solidifying material slurry discharge port during penetration. A columnar pile building method characterized by rotating and dispersing the solidifying material slurry in a plane on the excavating blade at the same time as discharging and creating a columnar pile while stirring and mixing with the ground soil. A drilling blade having both blades is provided on the tip side of the hollow stirring shaft,
At least one straight upper wing該掘Kezutsubasa, have a length and a predetermined height extending from the side surface of the hollow stirring shaft to the tip of該掘Kezutsubasa a and the vertical plate or inclined plate of forward downwardly inclined guide Set up a board,
Provided on the back side of the guide plate and on the stirring shaft is a solidified material slurry discharge port communicating with the ground solidified material slurry supply means,
The columnar pile for carrying out the columnar pile building method according to claim 1 , wherein the excavation blade has a portion for planarly dispersing the solidifying material slurry on the excavation blade at the same time as discharging. Creation device.

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