JP6618689B2 - Drilling and stirring device with co-rotation prevention wing - Google Patents

Description

  The present invention relates to an excavation and agitation apparatus with a co-rotation prevention blade that is used in a ground improvement method such as a deep mixing treatment method, and prevents the excavation soil from rotating together with the excavation blade and the agitation blade.

  If the soil is highly viscous (for example, clay, silt, etc.), the excavated earth and sand and the solidified milk will try to rotate along with the rotation of the drilling blades. As a result, a non-homogeneous column will be created and a co-rotation prevention wing will be required.

  Specifically, as disclosed in Patent Document 1 (Japanese Patent No. 1197295), in an auger type drilling device in which a drilling blade is provided at the lower end portion of a rotating shaft, a drilling diameter which is a rotating outer diameter of the drilling blade. It is more desirable to loosely fit the large-diameter co-rotation preventing wing to the rotating shaft.

  In this way, while the rotating shaft is actively rotated by the driving means in the ground, the tip of the co-rotation preventing wing touches the surrounding ground, so the co-rotation preventing wing hardly rotates in the ground. . In other words, a large angular velocity difference is generated between the rotating shaft and the co-rotation prevention blade, and this angular velocity difference causes the soil on the upper side and the lower side (excavation blade side) to be bordered with the co-rotation prevention blade as a boundary. It will be.

  In this specification, when the area to which the excavation action of the excavation blade extends is referred to as “operation volume”, the co-rotation prevention blade is located at the boundary portion of the operation volume. It works like a baffle that prevents co-rotation. By such a function, the operation volume is limited to a certain range, and as a result, the kneading by the excavating blade is good.

  Recently, there are increasing examples of ground improvement at the time of rebuilding a building, and ground such as buried soil and embankment is often targeted for improvement. In such ground, not only soil, but often foreign matters (for example, concrete galley, asphalt galley, crushed rocks, boulders, cobblestones, gravels, wood chips, etc.) are usually about 10 to 50 centimeters in diameter. Stuff).

If foreign matter is contained in the ground, the foreign matter may be caught between the excavation blade and the co-rotation prevention blade, and these blades may be deformed or damaged. Furthermore, if the foreign object remains sandwiched between the excavating blade and the co-rotation preventing blade, these blades, which should generate the angular velocity difference, rotate together as a result of being connected by the foreign material. The edge-cutting action of the anti-rotation wing will not be fulfilled. If it becomes like this, the quality of the ground improvement body will fall remarkably. Originally, foreign matter often has a strength exceeding that of soil cement, so even if the foreign matter remains in the ground improvement body, the quality of the ground improvement body is not impaired, but the edge cutting action of the co-rotation prevention wing is ineffective. Must not be
Japanese Patent No. 1197295 JP 2010-180647 A JP 2005-325548 A JP 2001-40651 A

  Then, an object of this invention is to provide the excavation stirring apparatus with a co-rotation prevention wing | blade which can suppress the bad influence even if a foreign material exists.

  According to a first aspect of the present invention, there is provided a rotating shaft that rotates in the ground, a rotating shaft that rotates in the ground, a drilling blade that projects from the lower end of the rotating shaft, and excavates earth and sand. An excavation and stirring device with a co-rotation prevention wing provided with a co-rotation prevention wing provided at a distance above and having a boss portion that circulates around the rotation shaft and is loosely fitted to the rotation shaft, Compared to the proximal end portion close to the boss portion, the distal end portion is formed to be away from the excavation blade.

  The shape of the co-rotation preventing wing may be formed with a smooth curve. Or the shape of a co-rotation prevention wing | wing may be formed of the several linear group bent in step shape.

  In this configuration, the co-rotation preventing wing is formed so that the tip portion is away from the excavation wing compared to the base end portion close to the boss portion. Even if there is a foreign object, the angle formed by the co-rotation prevention blade and the drilling blade is large, and the foreign object is pushed out by the co-rotation prevention blade toward the outer periphery of the column. Foreign matter is less likely to be caught between them.

  Therefore, the situation where the co-rotation preventing blade and the excavation blade rotate together is avoided, and the edge cutting effect by the co-rotation preventing blade is maintained. As a result, a good ground improvement body can be formed.

  According to the present invention, the anti-rotation blade is formed so that the tip portion is away from the excavation blade compared to the base end portion close to the boss portion, so that the foreign matter is pushed out to the outer peripheral side of the column and the foreign matter is excavated. It is possible to prevent the blade from being caught between the wing and the co-rotation prevention wing. As a result, it is possible to maintain the edge cutting effect by the co-rotation preventing wing and to form a good ground improvement body.

(Comparative example)
Prior to the description of the embodiment of the present invention, adverse effects due to foreign substances in the comparative example will be described with reference to FIGS. Here, FIG. 9 is a side view of the excavation and stirring device in the comparative example, and FIG. 10 is a cross-sectional view taken along line AA in FIG.

  In FIG. 9, the rotation shaft 2 has a center line 1, and a rotation force by a driving means (not shown) is applied to the center line 1 in the arrow N direction or in the opposite direction to rotate forward or reverse. Note that the forward / reverse rotation is switched in consideration of the operation of descending or ascending by the driving means. Although the position of the center line 1 may slightly fluctuate due to soil resistance or vibration in the ground, the following description is based on the assumption that the position of the center line 1 is fixed.

  Since the center line 1 is fixed, the tip edge of the excavation blade 3 provided at the lower end of the rotating shaft 2 describes a circular orbit (this is the column outer periphery 9) centered on the center line 1. More specifically, a plurality of claws 3a are provided on the lower side of the excavation blade 3, and excavation proceeds by rotating the claws 3a while biting into the soil.

  The co-rotation prevention blade 7 is provided above the excavation blade 3 by a predetermined distance on the rotary shaft 2. Specifically, the central portion (base end portion) of the co-rotation preventing wing 7 is a boss portion 7a that circulates around the rotation shaft 2 and is loosely fitted to the rotation shaft. The upper stopper 5 and the lower stopper 6 provided on the flange in the outer diameter direction from the rotary shaft 2 are positioned.

  A base end portion of the stirring blade 4 that is orthogonal to the excavation blade 3 (however, it is not essential and is optional) is further fixed above the upper stopper 5.

  As described above, when the rotating shaft 2 rotates, the stirring blade 4 and the excavation blade 3 rotate integrally therewith, but the co-rotation preventing blade 7 is almost stationary and a large angular velocity difference is generated. Due to this angular velocity difference, the edge cutting action described above is achieved.

  The operation volume described above is obtained by multiplying the area in the column outer periphery 9 by the sum of the interval t1 between the co-rotation prevention blade 7 and the excavation blade 3 and the height of the excavation blade 3. Since this area is fixed by the diameter of the excavating blade 3, it can be considered to be constant. Therefore, in order to reduce the operation volume and increase the kneading effect, the interval t1 must be set small.

  The co-rotation prevention wing 7 of the comparative example is formed in a straight line in substantially the same manner as the excavation wing 3 in plan view. When the excavation blade 3 rotates with respect to the substantially stationary anti-rotation blade 7, the anti-rotation blade 7 and the excavation blade 3 form a small corner, and cut through the soil at the interval t1 like scissors. It moves like this.

  Here, when the foreign object 8 having a height exceeding the interval t1 approaches between the co-rotation prevention blade 7 and the excavation blade 3, the foreign material 8 is interposed between the blades 7 and 3 as shown in FIG. It gets caught.

  Fortunately, the foreign object 8 only needs to be cut, but normally, the foreign object 8 plays a role as a connecting tool for connecting the excavation blade 3 and the co-rotation prevention blade 7, and as a result, the co-rotation prevention blade 7. Is forcibly rotated by the excavating blade 3. In this case, the edge cutting action is hardly achieved, and the quality of the ground improvement body is significantly deteriorated.

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an excavating and agitating apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line BB in FIG.

  In FIG. 1 and FIG. 2, the same elements as those in FIG. 9 and FIG. In FIGS. 1 and 2, each pair of the co-rotation prevention blade 10 and the excavation blade 3 or the co-rotation prevention blade 10 and the stirring blade 4 is shown in a single stage. In addition, the present invention can be similarly applied, and such a case is also included in the protection scope of the present invention.

  A feature of the present invention resides in the shape of the co-rotation preventing wing 10 in plan view. That is, as shown in FIG. 2, the co-rotation preventing wing 10 is formed so that the tip portion is away from the excavation wing 3 compared to the base end portion close to the boss portion 10 a. For this reason, even when the co-rotation preventing blade 10 and the excavation blade 3 are close to each other in plan view, the angle formed by the vicinity of the contact point between the co-rotation prevention blade 10 and the excavation blade 3 is large (this point is illustrated in FIGS. See 2 for comparison).

  Due to this relationship, the foreign object 8 moves so as not to be sandwiched between the co-rotation prevention blade 10 and the excavation blade 3 and to pass through the upper or lower excavation blade 3, as indicated by arrows in FIG. Then, it is pushed out to the outer peripheral side of the column. For this reason, according to the present invention, it is possible to employ an interval t2 that is smaller than the interval t1 of the comparative example. As a result, it is possible to construct a high-quality ground improvement body by setting the operation volume smaller, 8 can be prevented from being sandwiched between the excavation blade 3 and the co-rotation prevention blade 10. As described above, when the interval is shortened, the quality of the ground improvement body can be improved, while the problem of a trade-off relationship that the risk of foreign matter being caught increases can be solved at a time.

  In FIG. 2, two of the co-rotation preventing blades 10 are paired, but may be one or three or more.

  Furthermore, as illustrated in FIGS. 3 to 8, the shape of the co-rotation preventing wing 10 in plan view can be variously changed. For example, as shown in FIG. 3, the base end portion may start so as to be in contact with the boss portion 10 a and may have a curved shape that curves smoothly with a certain curvature.

  Alternatively, as shown in FIG. 4, the curvature may be larger than that in FIG. 3 so that the tip portion faces inward.

  Or as shown in FIG. 5, you may comprise by the some straight line group bent in step shape.

  Alternatively, as shown in FIG. 6, the base end portion may be bent so as to be orthogonal to the rotating shaft 2 and the tip end portion away from the excavation blade 3.

  Alternatively, as shown in FIG. 7, the base end side may be slightly inflated to the upper side of FIG.

  Furthermore, as shown in FIG. 8, the base end portion may be orthogonal to the boss portion 10a, then bent to the right in FIG. 8, and the curved portion may be continued to reach the distal end portion.

  Each of the various shapes in FIGS. 3 to 8 has advantages and disadvantages. However, any shape can be used to achieve certain effects. Therefore, these shapes are naturally included in the present invention. Unless the meaning of the above is changed, shapes not shown in the drawings also belong to the protection scope of the present invention.

  The excavation and stirring device with a co-rotation preventing blade according to the present invention can be suitably used in, for example, the field of ground improvement.

The side view of the excavation stirring apparatus in one embodiment of this invention BB sectional view of FIG. Sectional drawing which shows the shape of the co-rotation prevention blade in the 1st example of this invention Sectional drawing which shows the shape of the co-rotation prevention blade in the 2nd example of this invention Sectional drawing which shows the shape of the co-rotation prevention wing | blade in the 3rd example of this invention Sectional drawing which shows the shape of the co-rotation prevention blade in the 4th example of this invention Sectional drawing which shows the shape of the co-rotation prevention wing | blade in the 5th example of this invention Sectional drawing which shows the shape of the co-rotation prevention blade in the 6th example of this invention Side view of excavating and stirring device in comparative example AA line sectional view of FIG.

DESCRIPTION OF SYMBOLS 1 Centerline 2 Rotating shaft 3 Excavation blade 3a Claw 4 Agitation blade 5 Upper stopper 6 Lower stopper 7, 10 Co-rotation prevention blade 7a, 10a Boss part 8 Foreign material 9 Column outer periphery t1, t2 space | interval

Claims (3)

A rotating shaft that rotates in the ground,
A drilling wing projecting at the lower end of the rotary shaft and excavating earth and sand;
Excavation with a co-rotation prevention wing provided with a co-rotation prevention wing provided at a predetermined distance above the excavation wing on the rotation shaft and having a boss portion that circulates around the rotation shaft and is loosely fitted to the rotation shaft A stirring device,
The co-rotation preventing wing than the base end portion close to the boss portion in a plan view, by the leading end portion is formed so as to form the shape away from the drilling blade, and the drilling blade and the co-rotation prevention wings The angle between the co-rotation prevention blade and the excavation blade is expanded as compared with the case where both are linear , and the co-rotation prevention blade is configured to push out foreign matter to the outer peripheral side of the column. Drilling and stirring device with co-rotation prevention blade. The excavation and stirring apparatus with a co-rotation prevention wing according to claim 1, wherein the shape is formed by a smooth curve. The excavation and agitation device with anti-rotation blades according to claim 1, wherein the shape is formed by a plurality of straight line groups that are bent in a step shape.

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