JP2012184612A - Ground improvement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground improvement device for increasing its excavating efficiency and agitating efficiency to sufficiently agitate and mix excavation soil and filler together, and also increasing its improving accuracy.SOLUTION: The ground improvement device comprises: an excavating member 30 supported at the front end of an excavating rod 10 via a single main shaft part 21; a casing 20 to be rotated integrally with the excavating member 30; an agitating member 40 having an agitating shaft 41 rotatably supported at both ends by the excavating member 30 and the casing 20 and an agitating blade 42 provided on the agitating shaft 41; an agitating blade 22 provided on the main shaft part 21; a sun gear 2 provided on the excavating rod 10; a planetary gear 4 provided on the agitating member 40; a spiral 31 formed on the excavating member 30; a discharge hole 50 for the filler; and a driving source for rotating the casing 20, etc. By integrally rotating the excavating member 30 and the casing 20, the agitating shaft 41 being rotated is revolved around the main shaft part 21 to form an agitation region.

Description

  The present invention relates to a ground improvement device. More specifically, the present invention relates to an improvement in the structure of a ground improvement device that improves ground by mixing excavated soil and filler.

  When constructing piles on the ground, ground improvement is performed as a technique for improving the pile support (vertical support, horizontal support, pull-out support). For example, when soft ground exists in the vicinity of the pile head, it is possible to reduce an adverse effect that the displacement amount of the pile becomes large with respect to the horizontal force acting during the earthquake by constructing the pile after the ground improvement.

  For other applications for soil improvement, soil pollution control methods, such as contamination purification materials such as iron powder, are mixed with contaminated soil, and the surrounding soil is surrounded by ground improvement materials to prevent the outflow of contaminants. There is something like this.

  As an apparatus for carrying out such ground improvement, a drilling bit is provided at the lower end of the drilling shaft, and a stirring blade is attached to the drilling shaft above the bit in a plurality of stages. For example, a drilling shaft between the agitating blade and a drilling shaft between the agitating blade and the agitating blade has a corotation preventing blade (plate) supported rotatably (see, for example, Patent Document 1).

On the other hand, in such a ground improvement device, it is necessary to press-fit the co-rotation prevention wing into the unexcavated ground, and it may be difficult to excavate on hard ground. In addition, there is also proposed an apparatus that does not require a co-rotation preventing blade such that when the outer excavation pipe is rotated by a driving device, the bit provided on the bit shaft and the stirring blade revolve while rotating, (see Patent Document 2). .
Japanese Patent Publication No.58-29374 Japanese Utility Model Publication No. 7-15827

  However, the ground improvement device such as Patent Document 1 has a problem that it is difficult to adapt to hard ground and a problem that excavation efficiency is not sufficient. In addition, the ground improvement device such as Patent Document 2 has problems that excavation efficiency and agitation efficiency are not sufficient, agitation and mixing of excavated soil and filler are not sufficient, and improvement accuracy is not sufficient.

  Therefore, the present invention can be applied to hard ground, improves excavation efficiency and agitation efficiency, allows sufficient agitation and mixing of excavated soil and filler, and further improves the improvement accuracy. The purpose is to provide.

(About drilling efficiency)
In order to solve this problem, the present inventor has made various studies. First, when looking at the excavation efficiency, the conventional ground improvement device as described above may be provided with a co-rotation prevention wing, and the co-rotation prevention wing is in a state where both ends enter the ground wall, and the excavation member (for example, The excavating bit is provided so as not to rotate together with the excavating bit, thereby enabling the excavated soil to be sheared and more finely crushed. However, on the other hand, if there is a co-rotation preventing wing that penetrates into the unexcavated ground, the excavation efficiency may deteriorate because it becomes difficult to excavate the hard ground. In addition, when a plurality of excavation shafts (axes provided with excavation bits) are configured to perform a planetary motion as in the ground improvement device of Patent Document 2 described above, the horizontal direction is subjected to vertical resistance during excavation. Therefore, when excavating hard ground, it is difficult to increase the excavation speed and it is difficult to improve excavation efficiency.

(About stirring efficiency)
Further, as in the ground improvement device of Patent Document 2, when the stirring blades are simply connected to the excavation shaft (the shaft on which the excavation bit is provided) directly above the excavation mechanism, agitation is also performed on the excavation shaft. It is difficult to improve the stirring efficiency because it is carried out only in the central part. Even if the rotational speed is increased, there is an upper limit because of the relationship with the above-described resistance in the vertical and horizontal directions. In addition, when the stirring region is relatively narrow or the range in which the filler is discharged is narrow as in Patent Document 2, the range in which the excavated soil and the filler can be efficiently stirred is narrow.

(About mixing of excavated soil and filler)
When the filler discharge port is arranged at the upper part of the excavation stirring region as in the ground improvement device of Patent Document 2, the filler is not supplied to the stirring region and is not agitated / mixed during the excavation of the rod.

(Regarding correspondence to arbitrary diameter)
When the excavation member (for example, excavation bit) and the stirring blade are integrated and can be attached and detached at predetermined positions as in the ground improvement device of Patent Document 2, the diameter of each of the excavation member and the stirring blade is set. It is not easy to change.

(About improved accuracy)
When the excavation member is configured by an excavation bit as in the ground improvement device of Patent Document 2, it is impossible to perform such construction that the improved soil is pressed downward when the rod is pulled up. Further, when the excavation / stirring rotary shaft is cantilevered and the tip is a free end as in the ground improvement device of Patent Document 2, the shaft may be shaken during construction, and the improvement accuracy may be inferior.

  As described above, the present inventor who has made various studies has obtained new knowledge that leads to the solution of these problems. The present invention is based on such knowledge, in a ground improvement device for improving ground by mixing excavated soil and filler, a drilling member supported at the tip of a drilling rod via a single main shaft portion, A casing connected to the excavation member and rotating integrally with the excavation member, an agitation shaft rotatably supported by the excavation member on the front end side and the casing on the other end side, and an agitation provided on the agitation shaft A stirring member having blades, a stirring blade provided in the main shaft portion, a sun gear provided in the excavation rod, a planetary gear provided in the stirring member and meshed directly or indirectly with the sun gear, and a drilling member And a drive source for rotating the casing or the like, and at least the excavation member and the casing. By body rotation, while rotating the stirring shaft is that to form the stirred region is revolved around the main shaft.

(About drilling efficiency)
In the present invention, a spiral is formed in the excavation member, and then the excavation member is provided on a single shaft (single main shaft portion) so that the main shaft portion and the excavation shaft rotate coaxially. Compared with a device having an excavation axis, it is possible to reduce the resistance in the horizontal direction, especially during excavation. Therefore, according to the ground improvement device according to the present invention, excavation efficiency can be improved.

(About stirring efficiency)
Further, in the present invention, the excavated soil can be efficiently fed by a spiral to the stirring region above the excavating member so as to travel along the spiral blade, and the excavation is performed by revolving (planetary rotation) the stirring shaft. Since the soil is stirred, the stirring efficiency can be improved.

(About mixing of excavated soil and filler)
In the present invention, since the filler discharge hole is disposed at least closer to the excavation member than the agitation member, the filler can be supplied to the agitation region and agitated and mixed when the excavation rod is advanced. In addition, it is possible to perform excavation more efficiently by discharging water when the excavation rod is excavated using the discharge hole.

(Regarding correspondence to arbitrary diameter)
Further, in the present invention, since the agitation shaft is supported by the excavation member and the casing, the excavation member and the agitation member can be attached and detached independently without being integrated. Yes. For this reason, it is possible to change the excavation member and the agitation member to an arbitrary diameter by independently exchanging the excavation member and the agitation member in consideration of the ground conditions and the diameter necessary for excavation / agitation.

(About improved accuracy)
Further, in the present invention, the excavation member and the agitation member are not integrated, and are independent as described above, and the excavation member is formed with a spiral. And by rotating the spiral in reverse, it is possible to construct the improved soil that has been agitated and mixed with the agitating member while pressing it downward, so that it is possible to create an improved body with a higher density. it can. In addition, in the present invention, the excavation member and the casing both support the stirring shaft, and the possibility of the shaft being shaken during the construction is low. Therefore, the improvement accuracy can be improved also in this respect.

(About reduction of discharged soil)
Further, when the excavation rod is pulled up, the excavation member and the spiral are rotated in the reverse direction to press the improved soil downward, thereby reducing the residual soil discharged to the ground.

  In the ground improvement device as described above, a plurality of stirring shafts are preferably provided. It is also preferable that a plurality of stirring blades are provided.

  Furthermore, in the ground improvement device as described above, it is preferable that the stirring blades are inclined. In this case, the relationship between the inclination angle θ1 of the stirring blade and the inclination angle θ2 of the spiral is more preferably θ1 ≦ θ2.

  Further, in the ground improvement device as described above, it is preferable that the excavation rod has a double tube structure including an outer tube and an inner tube. In this case, it is also preferable that one of the outer tube and the inner tube is a tube that does not rotate during the ground improvement work.

  According to the present invention, excavation efficiency and agitation efficiency can be improved, and excavation soil and filler can be sufficiently agitated and mixed. Further, improvement accuracy can be improved and discharged soil can be reduced.

It is a fragmentary sectional view which shows the structure of the front-end | tip part among the ground improvement apparatuses in one Embodiment of this invention. It is sectional drawing which shows the whole ground improvement apparatus. It is sectional drawing which shows the whole ground improvement apparatus, Comprising: The stationary part which does not rotate is represented with the mesh ground. (A) When there is a transmission gear, (B) It is a top view which shows the outline of rotation operation | movement of a sun gear etc. when there is no transmission gear. It is a top view which shows roughly a motion of each member, such as a main axis | shaft stirring blade, a stirring shaft, and a planetary stirring blade, when a casing etc. are rotated. FIG. 6 is a plan view schematically showing the movement of each member at one time point after FIG. 5. FIG. 7 is a plan view schematically showing the movement of each member at one time point after FIG. 6. It is a figure which shows an example of the ground improvement apparatus in case the diameter required for excavation and stirring differs. It is a figure which shows an example of the ground improvement apparatus in case a diameter required for excavation and agitation differs again. It is a figure which shows an example of the ground improvement apparatus in case the diameter required for excavation and stirring further differs. It shows an example of construction procedures using a ground improvement device and a pile driver. (A) Pile core alignment with a pile driver, (B) Soil cement column construction by mixing and mixing cement milk and ground, (C) Soil Cement column construction completed, (D) Steel pipe pile built, (E) Steel pipe pile pile alignment, verticality check, (F) Steel pipe pile rotating embedded in soil cement column, (G) Steel pipe pile It is a figure showing each process of confirmation of the pile head level. It is a figure which shows the stirring blade and spiral which were inclined with respect to the plane (surface perpendicular to the vertical axis), and the inclination angles θ1 and θ2.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  FIG. 1 shows an embodiment of a ground improvement device 1 according to the present invention. The ground improvement device 1 according to the present invention includes a drilling rod 10, a gear casing (casing) 20, a drilling member 30, a stirring member 40, stirring blades 22, 42, a sun gear 2, a transmission gear 3, a planetary gear 4, and a filler. The apparatus is provided with a discharge hole 50 and the like, and improves the ground G by mixing excavated soil and filler in the borehole 200 when excavating the ground G. The filler as used herein is a concept including not only a hardener such as cement milk but also bentonite mud, bentonite powder, iron powder and the like.

  The excavation rod 10 of the present embodiment has a double tube structure composed of an outer tube 11 and an inner tube 12. In the present embodiment, such a double tube excavation rod 10 is driven by a single drive source (auger 102). (See FIGS. 2 and 3). The gear casing 20, the excavation member 30, and the like are supported in a rotatable state at the tip (lower end) of the excavation rod 10. The excavation rod 10 has a hollow structure, and also serves as a pipe for supplying a filler such as cement milk from the ground surface side (base end side). During excavation of the ground G, the excavation rod 10 is operated by the pile driver 100 on the ground surface, and transmits the rotational driving force of an auger motor (not shown) to rotate the gear casing 20 and the like (see FIG. 1).

  The outer tube 11 is a tube that rotates the gear casing 20 and the like by transmitting the rotational driving force of the auger 102 at the time of ground improvement construction. The upper end (base end) portion of the outer tube 11 is connected to the rotational driving device 102a of the auger 102, and the lower end. The (tip) portion is connected to the gear casing 20.

  On the other hand, the inner pipe 12 is a pipe that does not rotate during ground improvement construction, and also serves as a pipe for supplying a filler from the ground surface side. The upper end (base end) portion of the inner tube 12 passes through the rotation drive device 102a. A supply hose 13 for feeding a filler is connected to the upper end of the inner tube 12. Further, the sun gear 2 is rigidly connected to the tip (lower end) of the inner tube 12 so as not to rotate relative to the inner tube 12, and the inner tube 12 and the sun gear 2 are always integrated in a stationary state. ing. In addition, in FIG. 3, the stationary part which does not rotate at the time of ground improvement construction, such as the inner pipe 12, is represented by the mesh ground.

  The gear casing 20 functions as a housing that houses the sun gear 2, the transmission gear 3, and the planetary gear 4, and is supported at the tip of the outer tube 11 of the excavation rod 10 (see FIG. 1). Further, the gear casing 20 rotatably supports one end of the stirring shaft 41 of the stirring member 40 via bearings 43 and 44. A single main shaft portion 21 (not a plurality) is connected to the center of the lower portion of the gear casing 20, and a drilling member 30 is connected via the main shaft portion 21, and the gear casing 20, the main shaft portion 21, and The excavation member 30 rotates as a unit.

  The excavation member 30 is a member that is supported at the tip of the excavation rod 10 together with the gear casing 20 and the main shaft 21. When excavating the ground G, air, water, drilling fluid, etc. are ejected from the nozzle 32 around the tip. Is configured to do. A plurality of excavating blades 33 are provided at the lower end of the excavating member 30 (see FIG. 1). Note that an area where excavation is performed by the excavation member 30 is also referred to as an excavation area in this specification (see FIG. 1).

  Further, the excavation member 30 is formed with a spiral 31 made of, for example, a right-handed screw (spiral) blade centered on the shaft 34 (see FIG. 1). The upper part of the spiral 31 has an open shape so that the excavated soil can easily flow into the stirring region (region where stirring is performed by the stirring blades 22 and 42). Thus, the excavation member 30 in which the spiral 31 is formed efficiently feeds the excavation soil to the stirring region above the excavation member 30 by the spiral blades. Moreover, in this embodiment, since the excavation member 30 in which the spiral 31 is formed is connected to a single main shaft portion (single axis) 21, compared to an apparatus having a plurality of excavation axes, it is particularly horizontal during excavation. Directional resistance is reduced. Moreover, if the excavation member 30 in which the spiral 31 was formed is used, there also exists an advantage that the excavation property at the time of excavation improves more.

  The agitation member 40 is a member for agitating and mixing the excavated soil and the filler, and in this embodiment, is constituted by an agitation shaft 41 and an agitation blade 42. The agitation shaft 41 is provided so as to revolve around the main shaft portion 21 while rotating during excavation, and the tip side thereof can be rotated via a bearing 45 at a part of the upper surface of the excavation member 30. It is supported. Moreover, the other end side (base end side) of the stirring shaft 41 is rotatably supported by the gear casing 20 via the bearings 43 and 44 as described above.

  The stirring blade 42 is a stirring blade that is rigidly coupled (coupled in a rigid state) to the stirring shaft 41 (also referred to as a planetary stirring blade in this specification). When the agitation shaft 41 rotates (rotation / revolution) in the excavation hole 200, the planetary agitation blade 42 also rotates to agitate and mix the excavated soil and the filler. For example, a plurality of planetary stirring blades 42 may be provided in a multistage manner along the stirring shaft 41, and this makes it possible to further improve the efficiency of stirring and mixing (see FIG. 1). In the present embodiment, as an example, a stirring member 40 is shown in which a set of two planetary stirring blades 42 is provided every 180 degrees (see FIG. 1). Of course, three or more planetary stirring blades are provided. The stirring blades 42 may be provided evenly. Alternatively, a plurality of planetary stirring blades 42 may be provided unevenly in the axial direction of the stirring shaft 41 or in the circumferential direction.

  Further, in the present embodiment, another stirring blade (also referred to as a main shaft stirring blade) 22 rigidly connected to the main shaft portion 21 is provided (see FIG. 1). By adding the main spindle stirring blade 22 to the planetary stirring blade 42, it becomes possible to more efficiently stir and mix the excavated soil and the filler. As with the planetary agitating blade 42 described above, three or more main spindle agitating blades 22 may be provided equally or non-uniformly in the axial direction or circumferential direction. Further, the main shaft stirring blade 22 may be inclined with respect to a horizontal plane (a plane perpendicular to the vertical axis) (see FIG. 1).

  Further, a filler discharge hole 50 is disposed, for example, on the shaft 34 of the excavating member 30 (see FIG. 1). The filler supplied through the piping such as the excavation rod 10 and the main shaft portion 21 is discharged from the discharge hole 50. Thus, according to the ground improvement device 1 of the present embodiment that discharges the filler from the discharge holes 50 arranged in the excavation member 30, the filler is more reliably supplied to the agitation region when excavating (growing) the ground G. Can be stirred and mixed. From the viewpoint of supplying the filler to the stirring region during excavation, it is sufficient that the discharge hole 50 is disposed at least on the tip side (closer to the excavating member 30) than the stirring member 40 described above. If it is arrange | positioned to the excavation member 30 (shaft 34), it is preferable at the point that supply to the stirring area | region of a filler becomes more reliable. Furthermore, it is preferable that the discharge hole 50 is disposed at the tip of the shaft 34 of the excavating member 30 in that the soil on the spiral can be mixed with the filler. It is also preferable to arrange a plurality of discharge holes 50 along the axial direction (see FIG. 1).

  Here, in this embodiment, when the gear casing 20 or the like is rotated by using the sun gear 2 or the planetary gear 4 or the like, the stirring member 40 revolves (planetary motion) while rotating. The sun gear 2 is provided in the vicinity of the tip of the inner tube 12 of the excavation rod 10 so as not to be relatively rotatable. The planetary gear 4 is provided in the vicinity of the proximal end of the stirring shaft 41 so as not to rotate relative to the stirring shaft 41. The sun gear 2 and the planetary gear 4 may be directly meshed with each other, but in the present embodiment, the transmission gear 3 is interposed between both the gears 2 and 4 (see FIG. 1). In this embodiment, the planetary gear 4 having a smaller diameter and a smaller number of gears than the sun gear 2 is employed.

  In the case where the excavating rod 10 having the double pipe structure as described above is used, when the gear casing 20 itself tries to rotate, the planetary gear (transmission gear) 4 also tries to rotate (revolve). At this time, since the sun gear 2 is stationary, the planetary gear 4 starts to rotate using the sun gear 2 as a reaction force. The rotation direction of the planetary gear 4 at that time is in principle the opposite direction to the gear casing 20 when the transmission gear 3 is present, and the same direction as the gear casing 20 when the transmission gear 3 is absent (see FIG. 4).

  Although it is possible to rotate the planetary gear 4 without the transmission gear 3, if a gear train without the transmission gear 3 is used to improve the ground having the same diameter as that with the transmission gear 3, it is larger. The sun gear 2 having a diameter and the gear casing 20 having a large projected area (the width B is larger) must be adopted, and there is a disadvantage in terms of construction (see FIG. 4). From this viewpoint, it is preferable to employ a gear train including the transmission gear 3.

  The movement of each member when the excavation member 30 or the like is rotated in the ground improvement device 1 will be described as follows (see FIGS. 5 to 7 and the like). First, during excavation, when the excavating member 30 is rotated clockwise via the gear casing 20 or the like (hereinafter also referred to as forward rotation), the spiral 31 composed of right-handed spiral blades is rotated by the same angle and the ground G In addition, the main shaft portion 21 and the main shaft agitating blade 22 also rotate at the same angle. Further, the stirring shaft 41 revolves around the main shaft portion 21 in the clockwise direction (planetary motion) and rotates at a predetermined angle (see FIGS. 5 to 7). The predetermined angle and the rotation direction at the time of rotation are determined by the gear ratio between the sun gear 2 and the planetary gear 4. For example, this embodiment adopts the planetary gear 4 having a smaller diameter and a smaller number of gears than the sun gear 2. In this case, the stirring shaft 41 revolves clockwise (planetary movement) while rotating at a predetermined rate counterclockwise. Needless to say, the movement when the gear casing 20 or the like is rotated in the reverse direction (rotated counterclockwise) follows the movement shown in FIGS. 7, 6, and 5, contrary to the case described above.

  As described above, in this embodiment, the multi-stage spindle agitating blade 22 is rotated clockwise by rotating the gear casing 20 or the like clockwise, and the multi-stage planetary agitating blade 42 is rotated clockwise while rotating around it. According to this, a wide stirring region can be formed in the vertical direction and the horizontal direction. Further, if the multi-stage spindle stirring blades 22 and the planetary stirring blades 42 are alternately arranged as in the present embodiment, the shearing force is improved or optimized, and the excavated soil and the filler are more efficiently stirred. Can be mixed (see Figure 1).

  Further, when the excavation rod 10 is pulled up from the ground G, it is also preferable to rotate the excavation member 30 and the like counterclockwise (reverse rotation). In such a case, since the spiral 31 of the excavation member 30 also rotates in the reverse direction, the improved soil agitated and mixed by the agitation member 40 is further agitated in the agitation region, and is pressed while pressing downward (bottom side of the excavation hole 200) By doing so, it becomes possible to create an improved body having a higher density. Further, when the main spindle agitating blade 22 and the planetary agitating blade 42 are inclined, it is possible to efficiently feed the improved soil to the excavation area (spiral area) by pressing the improved soil downward on the back side of the agitating blade (blade). It becomes.

  In addition, in the ground improvement device 1 of the present embodiment, since the agitation shaft 41 is supported at both ends by the gear casing 20 and the excavating member 30, the agitation shaft 41 is shaken during the construction. Is effectively suppressed. Therefore, this is also advantageous from the viewpoint of improving the accuracy of ground improvement.

  In the present embodiment in which the excavation member 30 and the agitation member 40 are not integrated, and the agitation shaft 41 is supported by the gear casing 20 and the excavation member 30 in this manner, the excavation member 30 and the agitation member 40 are agitated. The members 40 can be attached and detached independently. Therefore, in this ground improvement apparatus 1, the excavation member 30 and the agitation member 40 can be individually replaced and changed to an arbitrary diameter in consideration of the conditions of the ground G and the diameter necessary for excavation / agitation. Explaining with examples shown in FIGS. 8 to 10, when the diameters necessary for excavation / stirring are D1, D2, and D3, it is easy to replace with another excavation member 30 that matches the diameter. In addition, it is easy to replace the stirring member 40 with another stirring member 40 having a different diameter (the amount of protrusion of the planetary stirring blade 42 in the horizontal direction is different) (see FIGS. 8 to 10). Alternatively, when the main shaft portion 21 not provided with the main shaft agitating blade 22 is adopted, the projection amount (arm length) of the planetary agitating blade 42 in the horizontal direction is sufficient to reach the peripheral surface of the main shaft portion 21. It is easy to replace the stirring member 40 (see FIG. 10).

  Furthermore, according to the ground improvement device 1 of the present embodiment, if the gear casing 20 is rotated, the excavation member 30, the stirring member 40, and the like can be interlocked, so that the power source for rotation is a single one. It is also advantageous in that it can be completed.

  Next, the pile driving machine 100 used when the ground G is improved using the ground improvement device 1 as described above and the construction procedure thereof will be briefly described (see FIG. 11).

  The pile driving machine 100 includes a leader 101, an auger 102, a steadying device 103, and the like. After excavating the ground G, a pile (for example, a steel pipe pile) 500 is rotated and embedded in the excavation hole 200. Machine (see FIG. 11). An auger (pile rotation device) 102 serving as a rotation drive source is provided so as to move during pile driving along a leader 101 erected in the vertical direction, and moves up and down along the longitudinal direction of the leader 101. A steel pipe pile 500 is connected to the auger 102 directly or via a yatco (not shown), and the auger 102 is rotated to rotate the steel pipe pile 500 and penetrate into the ground G.

  When excavating the ground G using the pile driving machine 100 and the ground improvement device 1 to improve the ground, first, the pile core position of the pile driving machine 100 is aligned with a predetermined position of the ground G to be constructed (FIG. 11 ( A)), the ground G is excavated by the excavating member 30 of the ground improvement device 1, and the soil is improved by stirring and mixing the filler (for example, cement milk) and the soil (soil) of the ground G. Is built (see FIG. 11B). When the construction is completed, the excavation rod 10 is pulled out from the excavation hole 200 (see FIG. 11C), and the steel pipe pile 500 is constructed (see FIGS. 11D to 11G).

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in each of the above-described embodiments, the shapes of the main spindle agitating blade 22 and the planetary agitating blade 42 are simply referred to. However, these shapes and sizes are improved by mixing and excavating the excavated soil. There is no particular limitation as long as it can be performed. For example, as shown in FIG. 8, an arm-shaped planetary stirring blade 42 having a radial tip bent upward in the vertical direction may be employed, or as described in the present embodiment, a flat surface (on the vertical axis) may be used. A planetary stirring blade 42 inclined with respect to a vertical plane) may be employed.

  Further, when the stirring blade 22 (42) inclined with respect to a plane (a plane perpendicular to the vertical axis) is employed, the inclination angle θ1 is not particularly limited, but 10 ° in consideration of actual construction. ≦ θ1 ≦ 30 ° is preferable from a practical viewpoint such as stirring and mixing efficiency (see FIG. 12). Further, the inclination angle θ2 of the spiral 31 of the excavating member 30 is not particularly limited, but it is preferable that 10 ° ≦ θ2 ≦ 30 ° in consideration of an actual excavation state and the like.

  Although these inclination angles θ1 and θ2 can be set independently of each other, in the ground improvement device 1 such as the above-described embodiment, the inclination angle θ1 of the stirring blade 22 (42) and the inclination angle θ2 of the spiral 31 are It may be optimal that θ1 ≦ θ2. When θ1 is smaller than θ2, the soil dug up by the spiral 31 at the time of excavation stays in the stirring region, and the number of times of stirring can be increased. On the other hand, when both inclination angles θ1 and θ2 are made equal, it becomes easy for the spiral 31 and the stirring blade 22 (42) to coincide with each other without causing wrinkles during excavation, and the resistance received from the soil is reduced. It becomes possible. The above may also apply to the case where the excavation member 30 and the like are reversely rotated when the excavation rod 10 is pulled up from the ground G.

  Moreover, although the ground improvement apparatus 1 provided with the two stirring shafts 41 was illustrated in embodiment mentioned above, this is only a suitable example, and also three or more stirring shafts 41 can also be provided, and a stirring shaft can be provided. 41 may be single.

  The present invention is suitable for application to a ground improvement device that improves ground by mixing excavated soil and filler.

DESCRIPTION OF SYMBOLS 1 ... Ground improvement device, 2 ... Sun gear, 4 ... Planetary gear, 10 ... Drilling rod, 11 ... Outer pipe, 12 ... Inner pipe, 20 ... Gear casing (casing), 21 ... Main shaft part, 22 ... Main shaft stirring blade ( Stirring blade), 30 ... excavating member, 31 ... spiral, 40 ... stirring member, 41 ... stirring shaft, 42 ... planet stirring blade (stirring blade), 50 ... discharge hole, 102 ... auger (drive source), G ... ground

Claims (7)

In the ground improvement device that improves the ground by mixing excavated soil and filler,
A drilling member supported via a single main shaft at the tip of the drilling rod;
A casing connected to the excavation member and rotating integrally with the excavation member;
A stirring shaft having a tip end side supported by the excavation member and a second end side rotatably supported by the casing, and a stirring member having a stirring blade provided on the stirring shaft;
A stirring blade provided in the main shaft portion;
A sun gear provided on the drilling rod;
A planetary gear provided on the stirring member and meshing directly or indirectly with the sun gear;
A spiral formed in the excavation member;
A discharge hole of the filler disposed at least closer to the excavation member than the stirring member;
A drive source for rotating the casing and the like;
With
A ground improvement device that revolves around the main shaft portion while rotating the stirring shaft by rotating the excavating member and the casing integrally to form a stirring region.   The ground improvement device according to claim 1, wherein a plurality of the stirring shafts are provided.   The ground improvement device according to claim 1 or 2, wherein a plurality of the stirring blades are provided.   The ground improvement device according to any one of claims 1 to 3, wherein the stirring blade is inclined.   The ground improvement device according to claim 4, wherein an inclination angle θ1 of the stirring blade and an inclination angle θ2 of the spiral satisfy θ1 ≦ θ2.   The ground improvement apparatus according to any one of claims 1 to 5, wherein the excavation rod has a double pipe structure including an outer pipe and an inner pipe.   The ground improvement device according to claim 6, wherein one of the outer pipe and the inner pipe is a pipe that does not rotate during ground improvement construction.