JP2019132043A - Ground improvement device - Google Patents

Abstract

To provide a projecting piece mounting structure capable of preventing breakage of a projecting piece, occurrence of bending deformation of the projecting piece, and simple and quick replacement in which the protruding piece is provided on a horizontal cylindrical body rotatably fitted on a horizontal shaft provided on an excavation shaft and provided for vertical rotation of three-dimensional agitation of excavated soil in a ground improvement device.SOLUTION: A projecting piece mounting body 21 having a recess 22 capable of accommodating a shaft portion forming a base end portion of a projecting piece 13 and having a base end 23 having a larger diameter than an outer diameter of the shaft portion is welded to an outer peripheral surface of a horizontal cylindrical body 12 along an outer peripheral edge of a base end surface with the base end surface of the projecting piece mounting body 21 in abutting state. The shaft portion formed by the base end portion of the protruding piece 13 is accommodated in the recess 22 of the protruding piece mounting body 21. The protruding piece 13 has a structure in which it is detachably attached with a structure for preventing the protruding piece from coming out of the recess 22 by, for example, bolting, instead of welding.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a ground improvement device, and more specifically, in civil engineering, building foundation work, etc., a lime-based or cement-based slurry-like solidifying agent (hereinafter also simply referred to as a solidifying agent) while excavating soft ground into a columnar shape or the like. ), And this solidifying agent and excavated soil (earth and sand) are mixed, stirred and solidified to solidify and form a soft ground into a columnar shape and improve it to a high strength one. The present invention relates to a ground improvement device.

  Conventionally, this type of ground improvement device is basically provided with a drilling blade provided near the tip of a rotating drilling shaft and one or more stirring blades provided above the drilling blade. With this, the tip of the rotating excavating shaft is pushed into the ground, the ground is excavated with the excavating blade, and the earth and sand that has been excavated with the agitating blade are stirred, and the upper stirring blade is used from the vicinity of the tip of the excavating shaft. The solidifying agent to be discharged and the excavated soil are mixed and stirred. In this case, since the excavated soil is only mixed and stirred in the horizontal direction (lateral direction) around the excavation axis, there is a problem in mixing and stirring properties. In addition to mixing and stirring around, a ground improvement device has been proposed that can mix and stir excavated soil around a horizontal shaft body that protrudes laterally from the excavating shaft, that is, longitudinally. (For example, refer to Patent Document 1 and Patent Document 2).

  The ground improvement device described in Patent Document 1 has the following configuration. That is, a rotating excavation shaft, an excavation blade provided near the tip of the excavation blade, and an outer fitting that is above the excavation blade and freely rotatable relative to the excavation shaft about its axis. A support body (annular body), a horizontal shaft body fixed to the support body so as to project laterally, and externally fitted to the horizontal shaft body so as to be freely rotatable relative to the horizontal axis. A horizontal cylindrical body, and three or more projecting pieces fixed on the outer peripheral surface of the horizontal cylindrical body at an angular interval around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion. When the excavation shaft rotates and the support body and the horizontal shaft body do not rotate around the excavation axis, the horizontal cylindrical body is abutted against the protruding piece and the horizontal cylindrical body is moved along the horizontal axis of the horizontal axis body together with the protruding piece. A striking unit (rotating drive unit) that rotates around (vertically rotates). In this ground improvement device, the horizontal shaft body has a length that is located on the outer side of the circumference drawn by the tip of the excavation blade as the tip of the excavation blade rotates as seen from the axial direction of the excavation shaft. The horizontal cylindrical body is rotatable around the axis (horizontal axis) of the horizontal shaft body on the inner side of the circumference thereof.

  In the ground improvement device described in Patent Literature 1, when the excavation shaft is rotated with the ground (ground surface) as the excavation start surface, the tip (lower end) is pushed into the ground and lowered, and excavation proceeds by excavation blades. When the tip of the horizontal shaft hits the outer circumference (outside) of the digging diameter on the ground surface (the circumference drawn by the tip of the drilling blade rotating), and the horizontal shaft enters the excavated soil, The shaft body is constrained by hard soil that has not been excavated, and does not rotate around the axis of the excavation shaft. As a result, the earth and sand (clot) that is rotated in the direction of rotation by the excavating blade is prevented from co-rotating around the axis of the excavating shaft by the horizontal shaft body, and is mixed and stirred around the excavating axis. In addition, the striking part (rotation drive part) provided on the excavating shaft that rotates with the excavating shaft intermittently hits the protruding piece of the cylindrical body (horizontal cylindrical body) provided on the horizontal shaft body, The projecting piece and the tubular body (horizontal tubular body) are rotated around the axis of the horizontal shaft body. As a result, the excavated soil is mixed and stirred around the axis of the horizontal shaft body (longitudinal direction) by the protruding pieces (mixing and stirring means) provided on the horizontal cylindrical body, so to speak, it is mixed and stirred three-dimensionally. Therefore, the improved body to be consolidated thereafter has a stable consolidated strength with no unevenness as a whole.

  In the ground improvement device, the horizontal shaft body has a length located outside the circumference drawn by the tip of the excavating blade as the excavating blade rotates. Although the rotation of the horizontal shaft body around the axis of the excavation axis is ensured to be stopped by being restrained by the soil, the means for stopping the rotation of the horizontal shaft body is not limited to this. For example, the horizontal shaft body can be embodied as having a length at which the tip is located inward of the circumference drawn by the tip of the excavating blade. That is, a ring body that is provided with a horizontal shaft body and that is externally fitted to a drilling shaft is extended upward to form a cylindrical body (an outer pipe that extends vertically). For example, this cylindrical body is excavated above it. The cylindrical body may be prevented from rotating by being fixed to a heavy equipment mount (auger head) to which a motor connected to the upper end of the shaft is attached in order to impart rotation to the shaft (FIG. 1 of Patent Document 2). -See Fig. 5). Further, the horizontal shaft body is rotated together with the excavation shaft, while the striking portion (projecting portion) is provided so as to be relatively rotatable with respect to the excavation shaft, and the striking portion is stopped when the excavation shaft is rotated. The projecting piece (stirring body) provided on the horizontal cylindrical body that is externally fitted to the horizontal shaft body that rotates together with the striking portion (co-rotation prevention wing) that is stopped is applied to the horizontal shaft body. It is also possible to rotate the projecting piece vertically while rotating (rotating horizontally) around the excavation axis (see FIGS. 6 to 8 of Patent Document 2).

  By the way, in the ground improvement device (excavation stirrer in Patent Document 2) capable of obtaining the conventional three-dimensional mixed stirring as described above, the projecting piece is rotated around the axis of the horizontal shaft (around the horizontal axis). On the outer peripheral surface of the provided steel cylindrical body (horizontal cylindrical body), for example, it is provided in a form extending outward at equal angular intervals (radial arrangement) when viewed from the horizontal axis direction. The fixing of the piece to the outer peripheral surface of the horizontal cylindrical body is usually made of steel, and is a rod such as a round bar. From the standpoint of ease of manufacturing and maintenance, the shaft that is the base end of the protruding piece The end surface of the part is abutted against the outer peripheral surface of the horizontal cylindrical body, and the outer peripheral edge (corner angle) of the abutting surface is welded along the outer peripheral edge.

JP-A-8-120665 JP 2001-3352 A

  On the other hand, in the ground improvement device (excavation agitation device) with three-dimensional excavation soil mixing and stirring as described above, any of them is provided in the horizontal cylindrical body during the construction (mixing and stirring) process. By intermittently hitting the projecting piece and repeating it, the projecting piece is intermittently rotated around the horizontal axis of the horizontal shaft body together with the horizontal cylindrical body, and the vertical rotation is obtained. It has a structure. For this reason, since a large moment acts together with a large external force on the fixed portion (welded spot) of the projecting piece to the outer peripheral surface of the horizontal cylindrical body, a breakage of the welding occurs, Due to the breakage, the protruding piece sometimes fell off. Further, in the fixed structure in which the protruding piece is directly welded to the outer peripheral surface of the horizontal cylindrical body in this way, the protruding piece is relatively elongated like a round bar, and thus receives a blow for its rotation. As a result, bending deformation tends to occur, and thus the life of the protruding piece tends to be shortened.

  As described above, in order to prevent welding breakage in the projecting piece, to prevent it, or to generate a large bending deformation, work involving welding for repair and replacement is unavoidable. However, in particular, when such work becomes work at a construction site for ground improvement, there is a great difficulty in the repair and replacement work, which causes a delay in construction. This is because there are circumstances such as it is not easy to permanently install the welding machine at the construction site.

  The present invention is based on the above-mentioned problem caused by the mounting structure by welding the protruding piece to the horizontal cylindrical body in the ground improvement device as described above having a structure for mixing and stirring three-dimensional excavated soil. It is an object of the present invention to provide a mounting structure for a projecting piece to a horizontal cylindrical body that can prevent breakage of the welding, bend deformation of the projecting piece, and simplify and speed up the replacement work. Objective.

The present invention described in claim 1 is a rotating excavation shaft, an excavation blade provided near the tip of the excavation shaft, and protrudes laterally of the excavation shaft above the excavation blade and to the excavation shaft. A horizontal shaft body provided in a shape, a horizontal cylindrical body that is externally fitted to the horizontal shaft body so as to be rotatable around the horizontal axis line, and an outer peripheral surface of the horizontal cylindrical body. Three or more projecting pieces fixed at an angular interval around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion, and when the excavation shaft rotates, the projecting pieces intermittently hit the projecting pieces. In a ground improvement device comprising a striking unit that rotates the horizontal cylindrical body around a horizontal axis of the horizontal shaft body together with a piece,
A projecting piece mounting body having a recess capable of accommodating a shaft portion forming the base end portion of the projecting piece on the outer peripheral surface of the horizontal cylindrical body, the base end having a larger diameter than the outer diameter of the shaft portion, The base end surface of the projecting piece mounting body is brought into a butted state and is welded at the outer peripheral edge of the base end surface, and the shaft portion forming the base end portion of the projecting piece is accommodated in the recess of the projecting piece mounting body. The protruding piece is detachably attached to the concave portion without being welded, and has a retaining structure.

  According to a second aspect of the present invention, the horizontal cylindrical body has a polygonal cylindrical shape, and the protruding piece mounting body has a flat surface whose base end surface forms a flat surface and forms the outer peripheral surface of the horizontal cylindrical body. The ground improvement device according to claim 1, wherein the ground improvement device is abutted and welded.

According to a third aspect of the present invention, the base end portion of the protruding piece is provided with a shaft through hole in a direction intersecting the axial direction of the shaft portion, and is opposed to the concave portion of the protruding piece mounting body. A wall through hole that penetrates the wall of the recess is provided at a position that coincides with the shaft through hole when the shaft forming the base end of the protruding piece is accommodated in the recess. And
The retaining structure is by bolt tightening in which a bolt is passed through the wall through hole and the shaft through hole in a state where the shaft portion forming the base end portion of the protruding piece is accommodated in the recess. It is a ground improvement apparatus of any one of Claim 1 or 2.

According to a fourth aspect of the present invention, the base end portion of the projecting piece is provided with a shaft through hole in a direction intersecting the axial direction of the shaft portion, and is opposed to the recess of the projecting piece mounting body. A wall through hole that penetrates the wall of the recess is provided at a position that coincides with the shaft through hole when the shaft forming the base end of the protruding piece is accommodated in the recess. And
2. The retaining structure according to claim 1, wherein a shaft portion forming a base end portion of the protruding piece is inserted into the wall through hole and a split pin penetrating the shaft through hole in a state where the shaft portion is accommodated in the recess. It is the ground improvement apparatus of any one of 1 or 2.

  According to a fifth aspect of the present invention, a male screw is provided on the outer peripheral surface of the shaft portion that forms the base end portion of the protruding piece, and a female screw is provided on the inner peripheral surface of the concave portion. The ground improvement device according to any one of claims 1 and 2, wherein the male screw has a screw fastening structure to the female screw.

  According to a sixth aspect of the present invention, the protruding piece mounting body has a cylindrical shape or an annular shape, the concave portion is inside the cylindrical or annular inner peripheral surface, and the cylindrical or annular outer peripheral surface. Is substantially square in cross section, and the protruding piece mounting body is welded so as to rotate in a diagonal direction of the square when the horizontal cylindrical body rotates around the horizontal axis of the horizontal axis. The ground improvement device according to any one of Items 1 to 5.

  In the above-mentioned conventional ground improvement device, in the course of its use, the projecting piece is intermittently or intermittently subjected to a large blow, so that in addition to deformation and damage such as bending and wear, it becomes a horizontal cylindrical body. Since it is fixed by direct welding, the welding breakage and the dropout of the protruding piece are caused as described above. On the other hand, in the ground improvement device according to the present invention, since the fixing of the protruding piece to the horizontal cylindrical body has the mounting structure having the above-described configuration, the following specific effects can be obtained.

  In the ground improvement device according to the present invention, the fixing of the protruding piece to the horizontal cylindrical body is fixing with a protruding piece mounting body that is welded by abutting the base end face to the outer peripheral surface of the horizontal cylindrical body, The outer diameter of the base end portion, which is a welded portion of the protruding piece mounting body to the outer peripheral surface of the horizontal cylindrical body, is larger than the outer diameter of the shaft portion of the protruding piece. Therefore, as compared with a fixed structure in which the base end surface of the projecting piece is directly butted against the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, a longer welding length (welding range) can be secured. Therefore, the welding strength can be increased. For this reason, it is effective in preventing the fracture of the weld, and effective in preventing the protruding piece from falling off due to the fracture.

  Moreover, in the ground improvement device according to the present invention, the protruding piece is the protruding piece because the shaft portion forming the base end portion is accommodated in the protruding piece mounting body welded to the outer peripheral surface of the horizontal cylindrical body. The protruding length of itself can be made smaller than that of the conventional case where the protruding piece is directly butt welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if a protrusion piece receives the impact for the rotation (vertical rotation), it is hard to produce bending deformation. Therefore, the lifetime of the protruding piece is extended.

  Moreover, in the ground improvement device according to the present invention, even if the projecting piece needs to be changed and replaced, the fixing of the projecting piece accommodated in the projecting piece mounting body does not depend on welding. Can be simplified and speeded up, and work efficiency can be improved.

  According to the second aspect of the present invention, the welding is simplified by butting the flat surfaces, and the weld structure is simplified and the strength is increased. The retaining structure uses bolt tightening as described in claim 3, or uses split pins as described in claim 4, or uses screw tightening as described in claim 5, What is necessary is just to attach so that attachment or detachment is possible. In addition, as described in claim 6, it is preferable that the projecting piece mounting body is welded so that the outer peripheral surface forms a substantially square shape in cross section because of low resistance.

The front view (elevation figure) which shows schematic structure of the embodiment which actualized the ground improvement apparatus of this invention. FIG. 2 is a diagram (right side view) seen from the direction of arrow A1 in the ground improvement device of FIG. 1, and a striking portion is formed on the projecting piece of the horizontal cylindrical body that is stopped from rotating around the excavating shaft by rotating the excavating shaft. Explanatory drawing of the state which a horizontal cylinder rotates around a horizontal axis line with a protrusion piece. The enlarged view of P1 part of FIG. The partially broken sectional view explaining the attachment state of a protrusion piece in the S1-S1 line | wire of FIG. The enlarged view of P2 part of FIG. The figure explaining the example of a change which made the protrusion piece attachment body the thing of a square cylinder shape in FIG. In FIG. 4, the partially broken sectional view explaining another attachment state of a protrusion piece.

  An embodiment of a ground improvement device (excavation stirring device for ground improvement) according to the present invention will be described in detail with reference to FIGS. 1 to 5. In the figure, 101 is a ground improvement device, 1 is an excavation shaft (rotation drive shaft) having a substantially cylindrical shape (or hollow column shape), and is configured to rotate by a rotation drive means (not shown) provided above. An excavation blade 2 having a predetermined diameter (excavation diameter D) for excavating the ground protrudes in a direction substantially perpendicular to the excavation axis 1 by welding near the lower end (distal end of the excavation axis). It is provided as follows. In the vicinity of the lower end portion of the excavation shaft 1, a slurry-like solidifying agent discharge port 1a is provided, and a solidifying agent (not shown) is discharged from the pumping source through the inside of the excavation shaft 1 into the excavated soil K. It is comprised so that.

  A cylindrical body (circular pipe) 5 is externally fitted and attached to the outer periphery of the excavation shaft 1 as a support body of the horizontal shaft body 7 described below, and has a double pipe structure. The lower end portion of the cylindrical body 5 is held so as to be positioned above the excavating blade 2 by a predetermined height. Is the upper end of the cylindrical body 5 fixed to a mount that fixes a rotation drive means (motor) (not shown) that rotates the excavation shaft so that the cylindrical body 5 does not rotate around the axis of the excavation shaft 1? It is connected to another rotation driving means (motor) and is configured to rotate around the axis G1 of the excavating shaft 1 at a different rotational speed in the same direction as the excavating shaft 1 or at an appropriate rotational speed in the opposite direction. Yes.

  On the other hand, on both outer sides of the portion closer to the lower end of the cylindrical body 1, a horizontal shaft body 7 having a circular cross-section extending substantially linearly to the side at a right angle with respect to the cylindrical body 5 is shown in FIG. On the left and right sides, the outer diameter of the excavating blade 2 is the same as or shorter than the outer diameter. The left and right horizontal shaft bodies 7 are externally fitted (freely fitted) with tubular horizontal cylindrical bodies 12 and 12 that are rotatable about a horizontal axis (horizontal axis line) G2. However, the horizontal cylindrical body 12 has a structure in which the large diameter enlarged portion 10 provided at the end of the horizontal shaft body 7 does not come out of the horizontal shaft body 7.

  The horizontal cylindrical body 12 may be a circular tube (cylindrical shape whose outer peripheral surface is also a circle), but in this example, it is a polygonal cylindrical shape (the inner peripheral surface is a cross section, a circle, and the outer peripheral surface is a square with a cross section). (See FIGS. 2, 4, and 5). The outer tubular outer body 12 near the excavation axis 1 is described in detail later, but is substantially equiangular when viewed from the direction of the horizontal axis G2 of the horizontal axis 7 (around the horizontal axis). Although the details will be described later at intervals (intervals of 90 degrees), the round bars forming the protruding pieces 13 are provided in a protruding manner in a radial arrangement (see FIGS. 2, 4 and 5), and the horizontal cylindrical body 12 is provided. At the same time, it is rotatable around the horizontal axis G2. Of the excavating shaft 1, between the upper and lower sides of the horizontal shaft body 7 and the excavating blade 2, the projecting piece 13 is rotated about the horizontal axis G2, so that a round bar-shaped striking portion (rotation driving means) 11 is excavated. For example, when the rotation of the horizontal shaft body 7 around the excavation shaft 1 is stopped, the striking portion 11 that rotates together with the excavation shaft 1 is a horizontal cylindrical body. The projecting piece 13 and the striking portion so that the projecting piece 13 intermittently (intermittently) hits the projecting piece 13 provided on the projecting piece 12 and can rotate intermittently (vertically) around the horizontal axis G2 together with the horizontal cylindrical body 12. 11 and the length and arrangement. In addition, since the excavated soil is mixed and stirred around the horizontal axis G2 by excavating the ground and the protruding piece 13 is rotated vertically, the protruding piece 13 also serves as a stirring body. On the outer peripheral surface of the cylindrical body 12, the stirrer 15 made of a round bar shorter than the protruding piece 13 (on the side opposite to the excavation shaft) is the same angle as the protruding piece 13. It is provided by welding at intervals, and the mixing agitation around the horizontal axis G2 of the excavated soil is enhanced. In addition, without providing the independent hit | damage part 11, you may make it rotate the horizontal cylindrical body 12 with the protrusion piece 13 when the upper edge part 2a of the excavation blade 2 hits the protrusion pieces 13 and 13.

  Next, the attachment structure of the protrusion piece 13 to the outer peripheral surface of the horizontal cylindrical body 12 is demonstrated (refer FIG. 4, FIG. 5). In this example, the protruding piece mounting body 21 is welded to the outer peripheral surface (plane) of the horizontal cylindrical body 12 as follows. In other words, the flat surface that is the outer peripheral surface of the horizontal cylindrical body 12 has a recess 22 that penetrates the shaft portion that forms the base end portion (end portion on the horizontal cylindrical body 12 side) of the protruding piece 13 with an inner diameter that can be accommodated. The projecting piece mounting body 21 having a short cylindrical shape whose base end 23 has a larger diameter than the outer diameter of the shaft portion makes the base end surface (planar surface) of the projecting piece mounting body 21 abutted, and the outside of the base end surface. A weld bead (see double hatching in the figure) B exists along the periphery (circle) (see FIGS. 3 to 5), that is, the outer peripheral surface (plane) of the horizontal cylindrical body 12 and the protruding piece mounting body. It welds so that the weld bead B exists along the corner angle with the outer peripheral surface of 21. And the axial part which makes the base end part of the protrusion piece 13 is accommodated in the recessed part (short cylinder) 22 of the protrusion piece attachment body 21, and the protrusion piece 13 is bolted without welding as described below, The recess 22 is detachably attached with a retaining structure. In addition, although the protrusion piece attachment body 21 was made into the cylindrical shape penetrated in this example, it is good also as a bottomed cylinder body.

  The mounting structure of the projecting piece 13 is not limited as long as it can be attached to and detached from the recess 22 with a retaining structure, but in this example, the base end of the projecting piece 13 accommodated in the recess (short cylinder) 22 The (shaft portion) has a retaining structure in which a bolt 31 is passed through in a direction perpendicular to the shaft, and is detachable by tightening a nut 35 at the tip of the bolt 31. That is, in this example, the base end portion of the projecting piece 13 is provided with the shaft through hole 14 in a direction intersecting the axial direction of the shaft portion, and the inner wall surface of the projecting piece mounting body 21 facing the concave portion 22. In addition, a wall through hole 25 that penetrates the wall of the recess 22 is provided at a position that coincides with the shaft through hole 14 when the shaft portion that forms the base end portion of the protruding piece 13 is accommodated in the recess 22. In this accommodated state, the bolt 31 is passed through the wall through hole 25 and the shaft through hole 14, and the bolt 31 is tightened with a nut 35 to tighten the tip of the bolt 31.

  In this example, when the excavation shaft 1 is rotated without rotating the cylindrical body 5 that is the outer tube, the striking portion 11 rotates as shown in the left and right views of FIG. The projecting piece 13 intermittently hits the projecting pieces (round bars) 13 and 13 provided on the lateral cylindrical body 12 that is externally fitted to the lateral shaft body 7, and the projecting piece 13 extends around the lateral axis G <b> 2. Rotate with (rotate vertically). In this example, structurally, the protruding pieces 13 in the left and right horizontal shaft bodies 7 rotate in opposite directions when viewed from the direction of the axis G2.

  Based on the structure of the ground improvement device 101 of this example, when the excavating shaft 1 rotates and enters the ground (in the soil), excavation starts with the excavating blade 2, and the sediment K is excavated with the excavating blade 2. The ground is mixed and stirred around the shaft 1, and the ground is excavated in a cylindrical shape with an excavation diameter D that is substantially the same as the diameter of the excavation blade 2. At this time, the cylindrical body 5 is stopped, reversed, or controlled to rotate at a different rotational speed in the same direction as the excavation shaft 1, but in the excavation process, as described above, the excavation shaft The striking part 11 provided in 1 hits the projecting pieces 13 and 13 provided in the horizontal cylindrical body 12 intermittently, and the projecting piece 13 and the stirring piece 15 are rotated around the axis G2 of the horizontal shaft body 7, The excavation soil (sediment) K is mixed and stirred three-dimensionally.

  On the other hand, in this mixing and stirring process, the projecting piece 13 that is hit by the striking part 11 passes through the projecting piece mounting body 21 that is welded by abutting the base end face to the outer peripheral surface of the horizontal cylindrical body 12, and in the recess 22. It has a mounting structure by inserting the base end portion into the. Of the protruding piece mounting body 21, the base end 23, which is a welded portion to the outer peripheral surface of the horizontal cylindrical body 12, has an outer diameter larger than the outer diameter of the shaft portion of the protruding piece 13. That is, compared to a fixed structure in which the base end surface of the protruding piece is directly butted against the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, the welding length (the circumference around the shaft portion of the bead) is reduced. Long) can be secured for a long time, so that the welding strength can be increased. For this reason, it is effective in preventing the breakage of the welded portion of the protruding piece mounting body 21 to the horizontal cylindrical body 12, and effective in preventing the protruding piece 13 from falling off due to the breaking. In particular, in this example, since welding to the outer peripheral surface of the horizontal cylindrical body 12 of the protruding piece mounting body 21 is welding by butting with each other, the welding structure can be simplified. However, although not shown, the horizontal cylindrical body 12 may have a circular cross-section (outer periphery) that is not a square as in the present example, but a circular tube (cylindrical) shape. It can be appropriate. In addition, it is good to weld the protrusion piece attachment body with the structure where the whole outer periphery of the end surface becomes butted shape to the outer peripheral surface of the horizontal cylindrical body 12. FIG.

  Further, in this example, the protruding piece 13 is the protruding piece 13 itself because the protruding portion mounting body 21 welded to the outer peripheral surface of the horizontal cylindrical body 12 accommodates the shaft portion forming the base end portion. The projecting length can be reduced as compared with the conventional one in which the projecting piece is directly butt welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if the protruding piece 13 is hit by the rotation (vertical rotation), bending deformation hardly occurs, and thus the life of the protruding piece 13 is extended. Moreover, even if the projecting piece 13 needs to be deformed and replaced, the projecting piece accommodated in the projecting piece mounting body 21 is fixed by bolting structure not based on welding, so that it can be easily replaced on site. Speed up and work efficiency can be achieved.

  In addition, although the protrusion piece attachment body 21 is not restricted to a cylindrical thing, it is good for a cross section (outer periphery) to be a square thing. In this case, as in the protruding piece mounting body 21 shown in FIG. 6, the protruding piece mounting body 21 has a square diagonal direction in the longitudinal direction of the protruding piece 13 (rotation of the horizontal cylindrical body 12). It is good to weld this to the outer peripheral surface of the horizontal cylindrical body 12 so that it may rotate. This is because, with such a welded structure, the projecting piece mounting body 21 rotates in the diagonal direction of the square, so that the cut of earth and sand is better than in the case of rotating in the opposite direction, This is because the longitudinal resistance can be reduced.

  In the example described above, the retaining structure for the recess 22 of the projecting piece 13 is the above-described bolt tightening structure. However, in place of the bolt, a pin (for example, a split pin) that can prevent its own retaining is passed. The ends of both legs may be bent so as to be folded back in a retaining shape. This is because the retaining structure is only required to be able to prevent the protruding piece from being recessed from the recess and to be detachable. As another example, as shown in FIG. 7, a male screw 17 is provided on the outer peripheral surface of the shaft portion forming the base end portion of the protruding piece 13, while a female screw 27 is provided on the inner peripheral surface of the concave portion 22. The male screw 17 may be screwed into the female screw (screw hole) 27 and tightened.

  The present invention is not limited to the application to the ground improvement device of the above example, but the rotating excavation shaft, the excavation blade provided near the tip thereof, and the excavation blade above the excavation blade. A horizontal shaft body provided on the shaft so as to protrude laterally of the excavation shaft, and a horizontal cylindrical body that is externally fitted to the horizontal shaft body so as to be rotatable about the horizontal axis. And three or more projecting pieces that are fixed to the outer peripheral surface of the horizontal cylindrical body around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion, and the excavation shaft rotates. Sometimes, it can be widely applied to a ground improvement device comprising a striking portion that intermittently hits the protruding piece and rotates the horizontal cylindrical body around the horizontal axis of the horizontal axis together with the protruding piece.

  That is, in the ground improvement device 101 of the above example, the horizontal shaft body 7 that rotates relative to the excavation shaft 1 is stopped, or the cylindrical tubular body (outer tube) 5 that is externally fitted to the excavation shaft is stopped. It is embodied in what controls the rotation. For example, it is assumed that the cylindrical body (outer tube) 5 is short without extending up, and freely rotates around the axis at a predetermined height position of the excavation axis. The projecting length of the horizontal shaft body provided in this is made larger than the outer diameter of the excavating blade, and in the excavation process, the tip of the horizontal shaft body enters the outside of the ground excavated by the excavating blade, The rotation of the horizontal shaft body around the excavation axis may be restricted. Further, in the rotation of the excavation shaft, not the striking portion, but the horizontal shaft also rotates integrally with the excavation shaft, while the striking portion stops without rotating, and the projecting piece that rotates together with the horizontal shaft is affected by this striking. It is good also as what rotates around the horizontal-axis line of a horizontal-axis body, hitting a part. That is, in this case, the horizontal shaft body is provided so as to rotate together with the excavation shaft, and the striking portion is provided so as to be freely rotatable around the excavation shaft like the horizontal shaft body in the above example. By configuring the part as described above, the rotation around the excavation axis may be stopped or the rotation may be controlled.

  That is, the present invention excavates the projecting piece provided on the horizontal cylindrical body that is externally fitted to the horizontal shaft body so that the rotation about the drilling axis is stopped or controlled. Rotation around the excavation axis against the projecting piece provided on the horizontal cylindrical body that is externally fitted around the horizontal axis that rotates with the excavation axis, or hits the striking part that rotates with the axis The protrusion in the conventionally known ground improvement device having a configuration in which the protruding piece of the horizontal cylindrical body externally fitted to the horizontal shaft body is rotated vertically by hitting a hitting portion provided to be stopped or controlled. It can be widely applied as a structure for attaching a piece to a horizontal cylindrical body.

DESCRIPTION OF SYMBOLS 1 Excavation shaft 2 Excavation blade 2a Upper edge 5 of an excavation blade 5 Cylindrical body (support body)
7 Horizontal shaft body 11 Strike part 12 Horizontal cylindrical body 13 Stirring body 14 Shaft through hole 15 Stirring piece 17 Male screw 21 Protruding piece mounting body 22 Recess 23 Base end 25 of projecting piece mounting body Wall through hole 27 Female thread 31 Bolt 101 Ground improvement Equipment G1 Drilling axis Axis G2 Horizontal shaft B Axis B Welding bead K Drilling soil (earth and sand)

  The present invention relates to a ground improvement device, and more specifically, in civil engineering, building foundation work, etc., a lime-based or cement-based slurry-like solidifying agent (hereinafter also simply referred to as a solidifying agent) while excavating soft ground into a columnar shape or the like. ), And this solidifying agent and excavated soil (earth and sand) are mixed, stirred and solidified to solidify and form a soft ground into a columnar shape and improve it to a high strength one. The present invention relates to a ground improvement device.

  Conventionally, this type of ground improvement device is basically provided with a drilling blade provided near the tip of a rotating drilling shaft and one or more stirring blades provided above the drilling blade. With this, the tip of the rotating excavating shaft is pushed into the ground, the ground is excavated with the excavating blade, and the earth and sand that has been excavated with the agitating blade are stirred, and the upper stirring blade is used from the vicinity of the tip of the excavating shaft. The solidifying agent to be discharged and the excavated soil are mixed and stirred. In this case, since the excavated soil is only mixed and stirred in the horizontal direction (lateral direction) around the excavation axis, there is a problem in mixing and stirring properties. In addition to mixing and stirring around, a ground improvement device has been proposed that can mix and stir excavated soil around a horizontal shaft body that protrudes laterally from the excavating shaft, that is, longitudinally. (For example, refer to Patent Document 1 and Patent Document 2).

  The ground improvement device described in Patent Document 1 has the following configuration. That is, a rotating excavation shaft, an excavation blade provided near the tip of the excavation blade, and an outer fitting that is above the excavation blade and freely rotatable relative to the excavation shaft about its axis. A support body (annular body), a horizontal shaft body fixed to the support body so as to project laterally, and externally fitted to the horizontal shaft body so as to be freely rotatable relative to the horizontal axis. A horizontal cylindrical body, and three or more projecting pieces fixed on the outer peripheral surface of the horizontal cylindrical body at an angular interval around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion. When the excavation shaft rotates and the support body and the horizontal shaft body do not rotate around the excavation axis, the horizontal cylindrical body is abutted against the protruding piece and the horizontal cylindrical body is moved along the horizontal axis of the horizontal axis body together with the protruding piece. A striking unit (rotating drive unit) that rotates around (vertically rotates). In this ground improvement device, the horizontal shaft body has a length that is located on the outer side of the circumference drawn by the tip of the excavation blade as the tip of the excavation blade rotates as seen from the axial direction of the excavation shaft. The horizontal cylindrical body is rotatable around the axis (horizontal axis) of the horizontal shaft body on the inner side of the circumference thereof.

  In the ground improvement device described in Patent Literature 1, when the excavation shaft is rotated with the ground (ground surface) as the excavation start surface, the tip (lower end) is pushed into the ground and lowered, and excavation proceeds by excavation blades. When the tip of the horizontal shaft hits the outer circumference (outside) of the digging diameter on the ground surface (the circumference drawn by the tip of the drilling blade rotating), and the horizontal shaft enters the excavated soil, The shaft body is constrained by hard soil that has not been excavated, and does not rotate around the axis of the excavation shaft. As a result, the earth and sand (clot) that is rotated in the direction of rotation by the excavating blade is prevented from co-rotating around the axis of the excavating shaft by the horizontal shaft body, and is mixed and stirred around the excavating axis. In addition, the striking part (rotation drive part) provided on the excavating shaft that rotates with the excavating shaft intermittently hits the protruding piece of the cylindrical body (horizontal cylindrical body) provided on the horizontal shaft body, The projecting piece and the tubular body (horizontal tubular body) are rotated around the axis of the horizontal shaft body. As a result, the excavated soil is mixed and stirred around the axis of the horizontal shaft body (longitudinal direction) by the protruding pieces (mixing and stirring means) provided on the horizontal cylindrical body, so to speak, it is mixed and stirred three-dimensionally. Therefore, the improved body to be consolidated thereafter has a stable consolidated strength with no unevenness as a whole.

  In the ground improvement device, the horizontal shaft body has a length located outside the circumference drawn by the tip of the excavating blade as the excavating blade rotates. Although the rotation of the horizontal shaft body around the axis of the excavation axis is ensured to be stopped by being restrained by the soil, the means for stopping the rotation of the horizontal shaft body is not limited to this. For example, the horizontal shaft body can be embodied as having a length at which the tip is located inward of the circumference drawn by the tip of the excavating blade. That is, a ring body that is provided with a horizontal shaft body and that is externally fitted to a drilling shaft is extended upward to form a cylindrical body (an outer pipe that extends vertically). For example, this cylindrical body is excavated above it. The cylindrical body may be prevented from rotating by being fixed to a heavy equipment mount (auger head) to which a motor connected to the upper end of the shaft is attached in order to impart rotation to the shaft (FIG. 1 of Patent Document 2). -See Fig. 5). Further, the horizontal shaft body is rotated together with the excavation shaft, while the striking portion (projecting portion) is provided so as to be relatively rotatable with respect to the excavation shaft, and the striking portion is stopped when the excavation shaft is rotated. The projecting piece (stirring body) provided on the horizontal cylindrical body that is externally fitted to the horizontal shaft body that rotates together with the striking portion (co-rotation prevention wing) that is stopped is applied to the horizontal shaft body. It is also possible to rotate the projecting piece vertically while rotating (rotating horizontally) around the excavation axis (see FIGS. 6 to 8 of Patent Document 2).

  By the way, in the ground improvement device (excavation stirrer in Patent Document 2) capable of obtaining the conventional three-dimensional mixed stirring as described above, the projecting piece is rotated around the axis of the horizontal shaft (around the horizontal axis). On the outer peripheral surface of the provided steel cylindrical body (horizontal cylindrical body), for example, it is provided in a form extending outward at equal angular intervals (radial arrangement) when viewed from the horizontal axis direction. The fixing of the piece to the outer peripheral surface of the horizontal cylindrical body is usually made of steel, and is a rod such as a round bar. From the standpoint of ease of manufacturing and maintenance, the shaft that is the base end of the protruding piece The end surface of the part is abutted against the outer peripheral surface of the horizontal cylindrical body, and the outer peripheral edge (corner angle) of the abutting surface is welded along the outer peripheral edge.

JP-A-8-120665 JP 2001-3352 A

  On the other hand, in the ground improvement device (excavation agitation device) with three-dimensional excavation soil mixing and stirring as described above, any of them is provided in the horizontal cylindrical body during the construction (mixing and stirring) process. By intermittently hitting the projecting piece and repeating it, the projecting piece is intermittently rotated around the horizontal axis of the horizontal shaft body together with the horizontal cylindrical body, and the vertical rotation is obtained. It has a structure. For this reason, since a large moment acts together with a large external force on the fixed portion (welded spot) of the projecting piece to the outer peripheral surface of the horizontal cylindrical body, a breakage of the welding occurs, Due to the breakage, the protruding piece sometimes fell off. Further, in the fixed structure in which the protruding piece is directly welded to the outer peripheral surface of the horizontal cylindrical body in this way, the protruding piece is relatively elongated like a round bar, and thus receives a blow for its rotation. As a result, bending deformation tends to occur, and thus the life of the protruding piece tends to be shortened.

  As described above, in order to prevent welding breakage in the projecting piece, to prevent it, or to generate a large bending deformation, work involving welding for repair and replacement is unavoidable. However, in particular, when such work becomes work at a construction site for ground improvement, there is a great difficulty in the repair and replacement work, which causes a delay in construction. This is because there are circumstances such as it is not easy to permanently install the welding machine at the construction site.

  The present invention is based on the above-mentioned problem caused by the mounting structure by welding the protruding piece to the horizontal cylindrical body in the ground improvement device as described above having a structure for mixing and stirring three-dimensional excavated soil. It is an object of the present invention to provide a mounting structure for a projecting piece to a horizontal cylindrical body that can prevent breakage of the welding, bend deformation of the projecting piece, and simplify and speed up the replacement work. Objective.

The present invention described in claim 1 is a rotating excavation shaft, an excavation blade provided near the tip of the excavation shaft, and protrudes laterally of the excavation shaft above the excavation blade and to the excavation shaft. A horizontal shaft body provided in a shape, a horizontal cylindrical body that is externally fitted to the horizontal shaft body so as to be rotatable around the horizontal axis line, and an outer peripheral surface of the horizontal cylindrical body. Three or more projecting pieces fixed at an angular interval around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion, and when the excavation shaft rotates, the projecting pieces intermittently hit the projecting pieces. A ground improvement device comprising a striking portion that rotates the horizontal cylindrical body around a horizontal axis of the horizontal shaft body together with a piece ,
A projecting piece mounting body having a recess capable of accommodating a shaft portion forming the base end portion of the projecting piece on the outer peripheral surface of the horizontal cylindrical body, the base end having a larger diameter than the outer diameter of the shaft portion, The base end surface of the projecting piece mounting body is brought into a butted state and is welded at the outer peripheral edge of the base end surface, and the shaft portion forming the base end portion of the projecting piece is accommodated in the recess of the projecting piece mounting body. In the ground improvement device in which the protruding piece is detachably attached to the recess without being welded ,
The protruding piece mounting body has a cylindrical shape or an annular shape, the concave portion is an inner side of the cylindrical or annular inner peripheral surface, and the cylindrical or annular outer peripheral surface has a substantially square shape in a cross section, In the rotation of the horizontal cylindrical body around the horizontal axis, the protruding piece mounting body is welded so as to rotate in the diagonal direction of the square .

  According to a second aspect of the present invention, the horizontal cylindrical body has a polygonal cylindrical shape, and the protruding piece mounting body has a flat surface whose base end surface forms a flat surface and forms the outer peripheral surface of the horizontal cylindrical body. The ground improvement device according to claim 1, wherein the ground improvement device is abutted and welded.

According to a third aspect of the present invention, the base end portion of the protruding piece is provided with a shaft through hole in a direction intersecting the axial direction of the shaft portion, and is opposed to the concave portion of the protruding piece mounting body. A wall through hole that penetrates the wall of the recess is provided at a position that coincides with the shaft through hole when the shaft forming the base end of the protruding piece is accommodated in the recess. And
The retaining structure is by bolt tightening in which a bolt is passed through the wall through hole and the shaft through hole in a state where the shaft portion forming the base end portion of the protruding piece is accommodated in the recess. It is a ground improvement apparatus of any one of Claim 1 or 2.

According to a fourth aspect of the present invention, the base end portion of the projecting piece is provided with a shaft through hole in a direction intersecting the axial direction of the shaft portion, and is opposed to the recess of the projecting piece mounting body. A wall through hole that penetrates the wall of the recess is provided at a position that coincides with the shaft through hole when the shaft forming the base end of the protruding piece is accommodated in the recess. And
2. The retaining structure according to claim 1, wherein a shaft portion forming a base end portion of the protruding piece is inserted into the wall through hole and a split pin penetrating the shaft through hole in a state where the shaft portion is accommodated in the recess. It is the ground improvement apparatus of any one of 1 or 2.

  According to a fifth aspect of the present invention, a male screw is provided on the outer peripheral surface of the shaft portion that forms the base end portion of the protruding piece, and a female screw is provided on the inner peripheral surface of the concave portion. The ground improvement device according to any one of claims 1 and 2, wherein the male screw has a screw fastening structure to the female screw.

  In the above-mentioned conventional ground improvement device, in the course of its use, the projecting piece is intermittently or intermittently subjected to a large blow, so that in addition to deformation and damage such as bending and wear, it becomes a horizontal cylindrical body. Since it is fixed by direct welding, the welding breakage and the dropout of the protruding piece are caused as described above. On the other hand, in the ground improvement device according to the present invention, since the fixing of the protruding piece to the horizontal cylindrical body has the mounting structure having the above-described configuration, the following specific effects can be obtained.

  In the ground improvement device according to the present invention, the fixing of the protruding piece to the horizontal cylindrical body is fixing with a protruding piece mounting body that is welded by abutting the base end face to the outer peripheral surface of the horizontal cylindrical body, The outer diameter of the base end portion, which is a welded portion of the protruding piece mounting body to the outer peripheral surface of the horizontal cylindrical body, is larger than the outer diameter of the shaft portion of the protruding piece. Therefore, as compared with a fixed structure in which the base end surface of the projecting piece is directly butted against the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, a longer welding length (welding range) can be secured. Therefore, the welding strength can be increased. For this reason, it is effective in preventing the fracture of the weld, and effective in preventing the protruding piece from falling off due to the fracture.

  Moreover, in the ground improvement device according to the present invention, the protruding piece is the protruding piece because the shaft portion forming the base end portion is accommodated in the protruding piece mounting body welded to the outer peripheral surface of the horizontal cylindrical body. The protruding length of itself can be made smaller than that of the conventional case where the protruding piece is directly butt welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if a protrusion piece receives the impact for the rotation (vertical rotation), it is hard to produce bending deformation. Therefore, the lifetime of the protruding piece is extended.

Moreover, in the ground improvement device according to the present invention, even if the projecting piece needs to be changed and replaced, the fixing of the projecting piece accommodated in the projecting piece mounting body does not depend on welding. simple faster, Ru been achieved the efficiency of work. Moreover, in the ground improvement device according to the present invention, the protruding piece mounting body has a cylindrical shape or an annular shape, and the concave portion is an inner side of the cylindrical or annular inner peripheral surface. The outer peripheral surface of the horizontal cylindrical body has a substantially square shape and is welded so that the projecting piece mounting body rotates in a diagonal direction of the square in the rotation of the horizontal cylindrical body around the horizontal axis. Therefore, the following specific effects can be obtained. That is, since it has such a welded structure, the projecting piece mounting body rotates in the diagonal direction of the square, so the earth and sand are cut better than in the case of rotating in the opposite direction, and the The resistance in the longitudinal direction can also be reduced.

According to the second aspect of the present invention, the welding is simplified by butting the flat surfaces, and the weld structure is simplified and the strength is increased. The retaining structure uses bolt tightening as described in claim 3, or uses split pins as described in claim 4, or uses screw tightening as described in claim 5, What is necessary is just to attach so that attachment or detachment is possible .

Front view illustrating a schematic configuration of a soil improvement device as a "reference example" which is different from the soil improvement apparatus of the present invention in that the "projecting piece mounting body" is different (elevation). FIG. 2 is a diagram (right side view) seen from the direction of arrow A1 in the ground improvement device of FIG. Explanatory drawing of the state which a horizontal cylinder rotates around a horizontal axis line with a protrusion piece. The enlarged view of P1 part of FIG. The partially broken sectional view explaining the attachment state of a protrusion piece in the S1-S1 line | wire of FIG. The enlarged view of P2 part of FIG. The figure explaining the example of embodiment of this invention which changed the protrusion piece attachment body into the thing of square cylinder shape in FIG. In FIG. 4, the partially broken sectional view explaining another attachment state of a protrusion piece.

Before explaining the embodiment of the ground improvement device (excavation stirring device for ground improvement) according to the present invention, the “reference example” is different from the ground improvement device of the present invention in that the “projection piece mounting body” is different. ”Will be described in detail with reference to FIGS. 1 to 5. In the figure, 101 is a ground improvement device, 1 is an excavation shaft (rotation drive shaft) having a substantially cylindrical shape (or hollow column shape), and is configured to rotate by a rotation drive means (not shown) provided above. An excavation blade 2 having a predetermined diameter (excavation diameter D) for excavating the ground protrudes in a direction substantially perpendicular to the excavation axis 1 by welding near the lower end (distal end of the excavation axis). It is provided as follows. In the vicinity of the lower end portion of the excavation shaft 1, a slurry-like solidifying agent discharge port 1a is provided, and a solidifying agent (not shown) is discharged from the pumping source through the inside of the excavation shaft 1 into the excavated soil K. It is comprised so that.

  A cylindrical body (circular pipe) 5 is externally fitted and attached to the outer periphery of the excavation shaft 1 as a support body of the horizontal shaft body 7 described below, and has a double pipe structure. The lower end portion of the cylindrical body 5 is held so as to be positioned above the excavating blade 2 by a predetermined height. Is the upper end of the cylindrical body 5 fixed to a mount that fixes a rotation drive means (motor) (not shown) that rotates the excavation shaft so that the cylindrical body 5 does not rotate around the axis of the excavation shaft 1? It is connected to another rotation driving means (motor) and is configured to rotate around the axis G1 of the excavating shaft 1 at a different rotational speed in the same direction as the excavating shaft 1 or at an appropriate rotational speed in the opposite direction. Yes.

  On the other hand, on both outer sides of the portion closer to the lower end of the cylindrical body 1, a horizontal shaft body 7 having a circular cross-section extending substantially linearly to the side at a right angle with respect to the cylindrical body 5 is shown in FIG. On the left and right sides, the outer diameter of the excavating blade 2 is the same as or shorter than the outer diameter. The left and right horizontal shaft bodies 7 are externally fitted (freely fitted) with tubular horizontal cylindrical bodies 12 and 12 that are rotatable about a horizontal axis (horizontal axis line) G2. However, the horizontal cylindrical body 12 has a structure in which the large diameter enlarged portion 10 provided at the end of the horizontal shaft body 7 does not come out of the horizontal shaft body 7.

The horizontal cylindrical body 12 may be a circular tube (a cylindrical shape whose outer peripheral surface is also a circle), but in this reference example (hereinafter also referred to as “this example” or “the above example”) , The circumferential surface has a cross section and a circular shape, and the outer circumferential surface has a cross section and a square shape (see FIGS. 2, 4, and 5). The outer tubular outer body 12 near the excavation axis 1 is described in detail later, but is substantially equiangular when viewed from the direction of the horizontal axis G2 of the horizontal axis 7 (around the horizontal axis). Although the details will be described later at intervals (intervals of 90 degrees), the round bars forming the protruding pieces 13 are provided in a protruding manner in a radial arrangement (see FIGS. 2, 4 and 5), and the horizontal cylindrical body 12 is provided. At the same time, it is rotatable around the horizontal axis G2. Of the excavating shaft 1, between the upper and lower sides of the horizontal shaft body 7 and the excavating blade 2, the projecting piece 13 is rotated about the horizontal axis G2, so that a round bar-shaped striking portion (rotation driving means) 11 is excavated. For example, when the rotation of the horizontal shaft body 7 around the excavation shaft 1 is stopped, the striking portion 11 that rotates together with the excavation shaft 1 is a horizontal cylindrical body. The projecting piece 13 and the striking portion so that the projecting piece 13 intermittently (intermittently) hits the projecting piece 13 provided on the projecting piece 12 and can rotate intermittently (vertically) around the horizontal axis G2 together with the horizontal cylindrical body 12. 11 and the length and arrangement. In addition, since the excavated soil is mixed and stirred around the horizontal axis G2 by excavating the ground and the protruding piece 13 is rotated vertically, the protruding piece 13 also serves as a stirring body. On the outer peripheral surface of the cylindrical body 12, the stirrer 15 made of a round bar shorter than the protruding piece 13 (on the side opposite to the excavation shaft) is the same angle as the protruding piece 13. It is provided by welding at intervals, and the mixing agitation around the horizontal axis G2 of the excavated soil is enhanced. In addition, without providing the independent hit | damage part 11, you may make it rotate the horizontal cylindrical body 12 with the protrusion piece 13 when the upper edge part 2a of the excavation blade 2 hits the protrusion pieces 13 and 13.

  Next, the attachment structure of the protrusion piece 13 to the outer peripheral surface of the horizontal cylindrical body 12 is demonstrated (refer FIG. 4, FIG. 5). In this example, the protruding piece mounting body 21 is welded to the outer peripheral surface (plane) of the horizontal cylindrical body 12 as follows. In other words, the flat surface that is the outer peripheral surface of the horizontal cylindrical body 12 has a recess 22 that penetrates the shaft portion that forms the base end portion (end portion on the horizontal cylindrical body 12 side) of the protruding piece 13 with an inner diameter that can be accommodated. The projecting piece mounting body 21 having a short cylindrical shape whose base end 23 has a larger diameter than the outer diameter of the shaft portion makes the base end surface (planar surface) of the projecting piece mounting body 21 abutted, and the outside of the base end surface. A weld bead (see double hatching in the figure) B exists along the periphery (circle) (see FIGS. 3 to 5), that is, the outer peripheral surface (plane) of the horizontal cylindrical body 12 and the protruding piece mounting body. It welds so that the weld bead B exists along the corner angle with the outer peripheral surface of 21. And the axial part which makes the base end part of the protrusion piece 13 is accommodated in the recessed part (short cylinder) 22 of the protrusion piece attachment body 21, and the protrusion piece 13 is bolted without welding as described below, The recess 22 is detachably attached with a retaining structure. In addition, although the protrusion piece attachment body 21 was made into the cylindrical shape penetrated in this example, it is good also as a bottomed cylinder body.

  The mounting structure of the projecting piece 13 is not limited as long as it can be attached to and detached from the recess 22 with a retaining structure, but in this example, the base end of the projecting piece 13 accommodated in the recess (short cylinder) 22 The (shaft portion) has a retaining structure in which a bolt 31 is passed through in a direction perpendicular to the shaft, and is detachable by tightening a nut 35 at the tip of the bolt 31. That is, in this example, the base end portion of the projecting piece 13 is provided with the shaft through hole 14 in a direction intersecting the axial direction of the shaft portion, and the inner wall surface of the projecting piece mounting body 21 facing the concave portion 22. In addition, a wall through hole 25 that penetrates the wall of the recess 22 is provided at a position that coincides with the shaft through hole 14 when the shaft portion that forms the base end portion of the protruding piece 13 is accommodated in the recess 22. In this accommodated state, the bolt 31 is passed through the wall through hole 25 and the shaft through hole 14, and the bolt 31 is tightened with a nut 35 to tighten the tip of the bolt 31.

  In this example, when the excavation shaft 1 is rotated without rotating the cylindrical body 5 that is the outer tube, the striking portion 11 rotates as shown in the left and right views of FIG. The projecting piece 13 intermittently hits the projecting pieces (round bars) 13 and 13 provided on the lateral cylindrical body 12 that is externally fitted to the lateral shaft body 7, and the projecting piece 13 extends around the lateral axis G <b> 2. Rotate with (rotate vertically). In this example, structurally, the protruding pieces 13 in the left and right horizontal shaft bodies 7 rotate in opposite directions when viewed from the direction of the axis G2.

  Based on the structure of the ground improvement device 101 of this example, when the excavating shaft 1 rotates and enters the ground (in the soil), excavation starts with the excavating blade 2, and the sediment K is excavated with the excavating blade 2. The ground is mixed and stirred around the shaft 1, and the ground is excavated in a cylindrical shape with an excavation diameter D that is substantially the same as the diameter of the excavation blade 2. At this time, the cylindrical body 5 is stopped, reversed, or controlled to rotate at a different rotational speed in the same direction as the excavation shaft 1, but in the excavation process, as described above, the excavation shaft The striking part 11 provided in 1 hits the projecting pieces 13 and 13 provided in the horizontal cylindrical body 12 intermittently, and the projecting piece 13 and the stirring piece 15 are rotated around the axis G2 of the horizontal shaft body 7, The excavation soil (sediment) K is mixed and stirred three-dimensionally.

  On the other hand, in this mixing and stirring process, the projecting piece 13 that is hit by the striking part 11 passes through the projecting piece mounting body 21 that is welded by abutting the base end face to the outer peripheral surface of the horizontal cylindrical body 12, and in the recess 22. It has a mounting structure by inserting the base end portion into the. Of the protruding piece mounting body 21, the base end 23, which is a welded portion to the outer peripheral surface of the horizontal cylindrical body 12, has an outer diameter larger than the outer diameter of the shaft portion of the protruding piece 13. That is, compared to a fixed structure in which the base end surface of the protruding piece is directly butted against the outer peripheral surface of the horizontal cylindrical body as in the conventional ground improvement device, the welding length (the circumference around the shaft portion of the bead) is reduced. Long) can be secured for a long time, so that the welding strength can be increased. For this reason, it is effective in preventing the breakage of the welded portion of the protruding piece mounting body 21 to the horizontal cylindrical body 12, and effective in preventing the protruding piece 13 from falling off due to the breaking. In particular, in this example, since welding to the outer peripheral surface of the horizontal cylindrical body 12 of the protruding piece mounting body 21 is welding by butting with each other, the welding structure can be simplified. However, although not shown, the horizontal cylindrical body 12 may have a circular cross-section (outer periphery) that is not a square as in the present example, but a circular tube (cylindrical) shape. It can be appropriate. In addition, it is good to weld the protrusion piece attachment body by the structure where the whole outer periphery of the end surface becomes butted shape to the outer peripheral surface of the horizontal cylindrical body 12. FIG.

  Further, in this example, the protruding piece 13 is the protruding piece 13 itself because the protruding portion mounting body 21 welded to the outer peripheral surface of the horizontal cylindrical body 12 accommodates the shaft portion forming the base end portion. The projecting length can be reduced as compared with the conventional one in which the projecting piece is directly butt welded to the outer peripheral surface of the horizontal cylindrical body. For this reason, even if the protruding piece 13 is hit by the rotation (vertical rotation), bending deformation hardly occurs, and thus the life of the protruding piece 13 is extended. Moreover, even if the projecting piece 13 needs to be deformed and replaced, the projecting piece accommodated in the projecting piece mounting body 21 is fixed by bolting structure not based on welding, so that it can be easily replaced on site. Speed up and work efficiency can be achieved.

Incidentally, the projecting piece mounting body 21 is different from that cylindrical, as in the aforementioned Reference Example, since the cross-section (periphery) is square, as projected piece mounting body 21 shown in FIG. 6, the protruding In the longitudinal direction of the piece 13 (rotation of the horizontal cylindrical body 12), it is preferable to weld this to the outer peripheral surface of the horizontal cylindrical body 12 so that the protruding piece mounting body 21 rotates in the diagonal direction of the square. . This is because, with such a welded structure, the projecting piece mounting body 21 rotates in the diagonal direction of the square, so that the cut of earth and sand is better than in the case of rotating in the opposite direction, This is because the longitudinal resistance can be reduced. In the ground improvement device of the reference example described with reference to FIGS. 1 to 5, the protruding piece mounting body 21 is the protruding piece mounting body 21 shown in FIG. 6. It is a form example.

  In the example described above, the retaining structure for the recess 22 of the projecting piece 13 is the above-described bolt tightening structure. However, in place of the bolt, a pin (for example, a split pin) that can prevent its own retaining is passed. The ends of both legs may be bent so as to be folded back in a retaining shape. This is because the retaining structure is only required to be able to prevent the protruding piece from being recessed from the recess and to be detachable. As another example, as shown in FIG. 7, a male screw 17 is provided on the outer peripheral surface of the shaft portion forming the base end portion of the protruding piece 13, while a female screw 27 is provided on the inner peripheral surface of the concave portion 22. The male screw 17 may be screwed into the female screw (screw hole) 27 and tightened.

  The present invention is not limited to the application to the ground improvement device of the above example, but the rotating excavation shaft, the excavation blade provided near the tip thereof, and the excavation blade above the excavation blade. A horizontal shaft body provided on the shaft so as to protrude laterally of the excavation shaft, and a horizontal cylindrical body that is externally fitted to the horizontal shaft body so as to be rotatable about the horizontal axis. And three or more projecting pieces that are fixed to the outer peripheral surface of the horizontal cylindrical body around the horizontal axis of the horizontal shaft body and fixed through the shaft portion of the base end portion, and the excavation shaft rotates. Sometimes, it can be widely applied to a ground improvement device comprising a striking portion that intermittently hits the protruding piece and rotates the horizontal cylindrical body around the horizontal axis of the horizontal axis together with the protruding piece.

  That is, in the ground improvement device 101 of the above example, the horizontal shaft body 7 that rotates relative to the excavation shaft 1 is stopped, or the cylindrical tubular body (outer tube) 5 that is externally fitted to the excavation shaft is stopped. It is embodied in what controls the rotation. For example, it is assumed that the cylindrical body (outer tube) 5 is short without extending up, and freely rotates around the axis at a predetermined height position of the excavation axis. The projecting length of the horizontal shaft body provided in this is made larger than the outer diameter of the excavating blade, and in the excavation process, the tip of the horizontal shaft body enters the outside of the ground excavated by the excavating blade, The rotation of the horizontal shaft body around the excavation axis may be restricted. Further, in the rotation of the excavation shaft, not the striking portion, but the horizontal shaft also rotates integrally with the excavation shaft, while the striking portion stops without rotating, and the projecting piece that rotates together with the horizontal shaft is affected by this striking. It is good also as what rotates around the horizontal-axis line of a horizontal-axis body, hitting a part. That is, in this case, the horizontal shaft body is provided so as to rotate together with the excavation shaft, and the striking portion is provided so as to be freely rotatable around the excavation shaft like the horizontal shaft body in the above example. By configuring the part as described above, the rotation around the excavation axis may be stopped or the rotation may be controlled.

  That is, the present invention excavates the projecting piece provided on the horizontal cylindrical body that is externally fitted to the horizontal shaft body so that the rotation about the drilling axis is stopped or controlled. Rotation around the excavation axis against the projecting piece provided on the horizontal cylindrical body that is externally fitted around the horizontal axis that rotates with the excavation axis, or hits the striking part that rotates with the axis The protrusion in the conventionally known ground improvement device having a configuration in which the protruding piece of the horizontal cylindrical body externally fitted to the horizontal shaft body is rotated vertically by hitting a hitting portion provided to be stopped or controlled. It can be widely applied as a structure for attaching a piece to a horizontal cylindrical body.

DESCRIPTION OF SYMBOLS 1 Excavation shaft 2 Excavation blade 2a Upper edge 5 of an excavation blade 5 Cylindrical body (support body)
7 Horizontal shaft body 11 Strike part 12 Horizontal cylindrical body 13 Stirring body 14 Shaft through hole 15 Stirring piece 17 Male screw 21 Protruding piece mounting body 22 Recess 23 Base end 25 of projecting piece mounting body Wall through hole 27 Female thread 31 Bolt 101 Ground improvement Equipment G1 Drilling axis Axis G2 Horizontal shaft B Axis B Welding bead K Drilling soil (earth and sand)

Claims (6)

A rotating excavation shaft, an excavation blade provided near the tip of the excavation shaft, a horizontal shaft body provided above the excavation blade and projecting laterally of the excavation shaft on the excavation shaft; A horizontal cylindrical body that is externally fitted so as to be rotatable relative to the horizontal axis around the horizontal axis, and an angular interval around the horizontal axis of the horizontal axis on the outer peripheral surface of the horizontal cylindrical body And three or more projecting pieces fixed via the shaft portion of the base end portion, and when the excavation shaft rotates, the projecting piece intermittently abuts the horizontal tubular body together with the projecting pieces. In the ground improvement device comprising a striking portion that rotates around the horizontal axis of the shaft body,
A projecting piece mounting body having a recess capable of accommodating a shaft portion forming the base end portion of the projecting piece on the outer peripheral surface of the horizontal cylindrical body, the base end having a larger diameter than the outer diameter of the shaft portion, The base end surface of the projecting piece mounting body is brought into a butted state and is welded at the outer peripheral edge of the base end surface, and the shaft portion forming the base end portion of the projecting piece is accommodated in the recess of the projecting piece mounting body. The ground improvement device is characterized in that the protruding piece is detachably attached to the recess without being welded.   The horizontal cylindrical body is formed in a polygonal cylindrical shape, and the protruding piece mounting body is welded by being abutted against and welded to a plane that forms a flat end surface of the horizontal cylindrical body. The ground improvement device according to claim 1, wherein The base end portion of the protruding piece is provided with a shaft through hole in a direction crossing the axial direction of the shaft portion, and the inner surface of the protruding piece mounting body facing the concave portion is provided with the concave portion. A wall through hole penetrating the wall of the recess is provided at a position corresponding to the shaft through hole when the shaft portion forming the base end portion of the protruding piece is accommodated,
The retaining structure is by bolt tightening in which a bolt is passed through the wall through hole and the shaft through hole in a state where the shaft portion forming the base end portion of the protruding piece is accommodated in the recess. The ground improvement device according to any one of claims 1 and 2. The base end portion of the protruding piece is provided with a shaft through hole in a direction crossing the axial direction of the shaft portion, and the inner surface of the protruding piece mounting body facing the concave portion is provided with the concave portion. A wall through hole penetrating the wall of the recess is provided at a position corresponding to the shaft through hole when the shaft portion forming the base end portion of the protruding piece is accommodated,
2. The retaining structure according to claim 1, wherein a shaft portion forming a base end portion of the protruding piece is inserted into the wall through hole and a split pin penetrating the shaft through hole in a state where the shaft portion is accommodated in the recess. The ground improvement apparatus of any one of 1 or 2.   A male screw is provided on the outer peripheral surface of the shaft portion that forms the base end portion of the protruding piece, and a female screw is provided on the inner peripheral surface of the concave portion, and the retaining structure is a screw tightening structure of the male screw to the female screw. The ground improvement apparatus of any one of Claim 1 or 2.   The protruding piece mounting body has a cylindrical shape or an annular shape, the concave portion is an inner side of the cylindrical or annular inner peripheral surface, and the cylindrical or annular outer peripheral surface has a substantially square shape in a cross section, The rotation of the horizontal cylindrical body about the horizontal axis of the horizontal shaft body is welded so that the protruding piece mounting body rotates in a diagonal direction of the square. The ground improvement device described.

Images