JP2013083069A - Ground improvement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground improvement device which can be prevented from becoming an inclined attitude and secure the quality of a formed ground improvement wall by stabilizing the drilled ground.SOLUTION: A ground improvement device is provided which includes first rotating shafts 11A-11C which are arranged parallel to each other and rotate around a vertical axis, and first drilling blades 12A-12C which are fixed to the lower ends of the first rotating shafts 11A-11C respectively and rotate horizontally. The central drilling blade 12B disposed at the center among the horizontally-arranged first drilling blades 12A-12C is located at a position below the other drilling blades 12A, 12C arranged on both sides thereof, and the other drilling blades 12A, 12C are located in an area α surrounded by a region extending obliquely upward from the outer peripheral edge 12c of the central drilling blade 12B by 45 degrees relative to a horizontal surface.

Description

  The present invention relates to a ground improvement device for excavating the ground, adding a ground improvement material to the excavated portion, mixing it with excavated soil, and performing ground improvement by stirring.

Conventionally, as ground improvement work, excavating the ground into blocks or walls and loosening the ground, for example, adding ground improvement material, mixing with the loosened ground, stirring, etc. A construction method is known (see, for example, Patent Document 1).
In Patent Document 1, a plurality of rods are arranged so that adjacent excavation blades do not contact each other, and a stirring blade is provided above the excavation blade of each rod. The ground improvement is such that the stirring blade is rotated in a direction different from the rotation direction of the rod, and the excavation blade is rotated together with the rod to move downward in the ground while mixing and stirring by the stirring blade. An apparatus is disclosed.

  Further, as a general ground improvement device, a triaxial rod is moved downward in the ground, and a propeller-like kneading blade and a spiral moving blade are arranged on the rod, and these kneading blades There is known a device in which the moving blades and the moving blades are alternately arranged so as not to interfere between adjacent rods. In this case, the excavating blades are rotated and dug down while applying a downward propulsive force by the weight of the ground improvement device. In such a ground improvement device, as shown in FIG. 7, when the improvement wall is constructed by continuous construction, a part of the subsequent ground improvement region K12 adjacent to the preceding ground improvement region K11 is overlapped. Drilling and improving.

Japanese Patent Laid-Open No. 11-217820

  However, in the conventional ground improvement device, as shown in FIG. 7, when excavating and improving adjacent ground improvement regions K11 and K12 to overlap each other, before the preceding ground improvement region K11 is sufficiently solidified, If the load (self-weight) of the ground improvement device 10 is applied to the ground G (shoulder ground Gc) adjacent to the preceding ground improved area K11 having a low strength in order to construct the row ground improved area K12, The ground Ga loosens and collapses to the preceding improvement wall K11 side, and receives earth pressure from the side opposite to the preceding ground improvement region K11 of the ground improvement device 10. Therefore, originally, the ground improvement device 10 itself escapes to the preceding ground improvement region K11 side and tilts where the ground improvement device 10 should be excavated and improved in the state in which the posture of the ground improvement device 10 is directed in the vertical direction Y as indicated by reference sign K12 ′. There was a problem that excavation and improvement were carried out with the tilted posture, and the quality of the improved improved wall could not be ensured.

  The present invention has been made in view of the above-described problems, and by stabilizing the excavated ground, it is possible to prevent the apparatus from being inclined and to ensure the quality of the ground improvement wall to be formed. An object of the present invention is to provide a ground improvement device capable of performing the above.

  In order to achieve the above object, in the ground improvement device according to the present invention, the ground improvement device performs ground improvement by moving in the ground, and rotates around a vertical axis and is arranged in parallel with each other. Of the rotary shaft and a drilling blade fixed to the lower end of the rotary shaft and rotating horizontally. Among the drilling blades arranged in the horizontal direction, the central drilling blade arranged in the center is the other of the other. It is characterized by being provided at a position below the excavating blade.

  In the present invention, the central excavation blade provided at the lower end of the rotation shaft located in the center among the three or more rotation shafts is provided in a state of projecting to a position below the other excavation blades on both sides, Since the central portion of the excavation cross section by the improved device is excavated in advance, loosening of the natural ground around the area excavated by the central excavation blade can be suppressed, and stable excavation can be performed.

  And in the ground improvement apparatus of this invention, the gravity center position of an apparatus turns into the position of a center excavation blade, and becomes the center of the width direction of an apparatus. Therefore, when constructing the ground improvement wall by continuous construction, it will be excavated and improved by overlapping a part of the subsequent ground improvement area with the previous ground improvement area, but it is adjacent to the previous ground improvement area The load applied to the ground of the excavation surface (corner ground) can be reduced. Therefore, it becomes possible to prevent the corner ground from loosening, so that the corner is prevented from collapsing to the preceding ground improvement region side and the ground improvement device to be inclined to the preceding ground improvement region side. Therefore, the ground improvement device can be excavated and improved in a vertical orientation without being inclined, and the quality of the ground improvement wall can be ensured.

In addition, the center of gravity of the device is located on the central excavation blade located at the center of the width direction of the device, and the tip of the central excavation blade is inserted into the ground surface at the beginning of excavation, so the ground improvement device moves in a horizontal direction and moves. Or tilting.
Furthermore, by performing the pre-excavation with the central excavation blade, the ground around the advance ground improvement area is loosened, and it becomes possible to reduce the rotational torque of the excavation blades provided on both sides of the central excavation blade. The required torque can be reduced, the capacity of the drive equipment can be suppressed, the cost can be reduced, and the weight and size of the apparatus can be reduced.

Further, in the ground improvement device according to the present invention, it is preferable that the other excavation blades are provided in a region surrounded by a range obliquely upward 45 degrees with respect to the horizontal plane from the outer peripheral edge of the central excavation blade.
In this case, since the excavating blades on both sides are arranged in the loose region surrounded by the range from the outer peripheral edge of the central excavating blade to 45 degrees obliquely upward with respect to the horizontal plane, the ground loosened by the excavating blades on both sides is arranged. Can be excavated efficiently.

Further, in the ground improvement device according to the present invention, the rotating shaft that supports the central excavating blade is provided with a stirring blade that rotates coaxially with the rotating shaft at the same height as the excavating blades on both sides. preferable.
In this case, it is possible to eliminate a portion where the earth and sand excavated by the central excavation blade are not agitated between the excavation blades on both sides and at a position above the central excavation blade. That is, since the earth and sand can be uniformly stirred even at the height positions of the excavating blades on both sides, it is possible to suppress an increase in rotational torque due to poor stirring around the rotation shaft of the central excavating blade.

  According to the ground improvement device of the present invention, by stabilizing the excavation ground, the device can be prevented from being inclined and the quality of the ground improvement wall to be formed can be ensured.

It is a front view which shows the structure of the ground improvement apparatus by embodiment of this invention. It is the AA arrow line view shown in FIG. 1, Comprising: It is the figure which looked at the ground improvement apparatus from the downward direction. It is an enlarged view which shows the structure of the 1st excavation blade shown in FIG. (A) is a diagram showing a first excavation area excavated by the first excavation blade and the second excavation blade in the ground improvement area, and (b) is a second excavation area excavated by the side cutter in the ground improvement area. FIG. It is the side view which mounted | wore the working machine with the ground improvement apparatus. It is a figure for demonstrating the ground improvement method using the ground improvement apparatus shown in FIG. 1, (a) is a figure which shows the state at the beginning of excavation, (b) is a figure which shows the construction state of the depth direction intermediate part It is. It is a figure which shows the attitude | position of the ground improvement apparatus at the time of the conventional ground improvement.

  Hereinafter, a ground improvement device according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ground improvement device 1 according to the present embodiment is a device for forming a ground improvement portion in a wall shape or a block shape, for example, immediately below the foundation of a building. Used as an attachment at the tip of the arm of the work machine 2 (see FIG. 5) such as a backhoe, and moved vertically in the ground while rotating the excavating blades provided at the lower ends of the three rotation axes. The ground improvement part is constructed by excavating, adding and mixing a ground improvement material to the excavated soil, and stirring.

Here, as the ground improvement material added to the excavated soil, an appropriate agent such as a liquid material such as cement milk or a powdered material can be employed depending on the purpose of the ground improvement.
In the following description, “excavated soil” includes a mixture of the ground excavated by the ground improvement device 1 and the ground improvement material. Moreover, in the ground improvement apparatus 1 shown in FIG. 1, the length dimension in the left-right direction toward the paper surface is referred to as “width direction X”.

  The ground improvement device 1 rotates about a vertical axis, and is fixed to a plurality of first rotation shafts 11 (11A, 11B, 11C) provided in parallel to each other, and respectively fixed to the lower ends of the first rotation shafts 11, and rotates horizontally. The first excavating blades 12 (12A, 12B, 12C) and the first rotary shafts 11 adjacent to each other are arranged in parallel to the first rotary shaft 11, and the rotation of the first rotary shaft 11 is transmitted to rotate around the vertical axis. A second rotating shaft 13 (13A, 13B) that rotates in a horizontal direction, a second excavating blade 14 (14A, 14B) that is fixed to the lower end of the second rotating shaft 13 and rotates in the horizontal direction, and an upper portion of the second excavating blade 14 2 is located in a cross-sectional area (second excavation area M2 to be described later) that is not excavated by the first excavating blade 12 and the second excavating blade 14, and a common outer tangent of the rotation trajectory of the adjacent first excavating blades 12 (in FIG. 2) Side cutter 15 provided along the symbol T) , And a.

  Of the three first rotary shafts 11A, 11B, and 11C, the central first rotary shaft 11B has a length dimension that projects downward from the first rotary shafts 11A and 11C on both sides, and each upper end 11a is described later. The support frame 16 (see FIG. 5) is supported so as to be rotatable about an axis. And the front-end | tip blade 17 which makes the shape pointed toward the downward direction at the front-end | tip of each 1st rotating shaft 11 is provided.

The three first rotating shafts 11 and the two third rotating shafts 13 are parallel to each other and spaced apart from each other by connecting shafts 18 at a plurality of locations (four locations in FIG. 1) in the axial direction Y. It is supported. The second rotary shafts 13A and 13B have the same length, are shorter than the first rotary shaft 11, and the second excavating blade 14 provided at the lower end is positioned above the first excavating blade 12. Yes.
The connecting shaft 18 extends along the width direction X, supports the first rotating shaft 11 and the second rotating shaft 13 rotatably, and connects the rotating shafts 11 and 13 in the horizontal direction.

In each of the first excavating blades 12A, 12B, and 12C, a rod-shaped blade shaft 12a extends radially outward from the lower end of the first rotating shaft 11A, 11B, and 11C, and a plurality of cutting bits are provided on the peripheral surface of the blade shaft 12a. 12b is arranged, and rotates around the central axis together with the first rotating shaft 11. As shown in FIG. 2, the second excavation blades 14 </ b> A and 14 </ b> B excavate a cross section having a smaller diameter than the first excavation blade 12, and rotate around the central axis along with the second rotation shaft 13.
Then, the first excavation blade 12 and the second excavation blade 14 excavate the first excavation region M1 shown in FIG.

  As shown in FIG. 3, the central excavation blade 12B located in the center in the width direction X among the first excavation blades 12A, 12B, and 12C is lower than the other excavation blades 12A and 12C disposed on both sides thereof. In the position. The other excavating blades 12A and 12C are provided in a region α surrounded by a range (θ = 45 ° in FIG. 3) that is obliquely upward 45 degrees from the outer peripheral edge 12c of the central excavating blade 12B. Yes.

  Moreover, as shown in FIG. 1, the 1st rotating shaft 11 is provided with the flow path over the whole axial direction inside, and the ground improvement material supplied to the upper end 11a distribute | circulates to a lower end. A spout 12d for injecting the ground improvement material is provided on the peripheral surface of the first excavation blade 12 in communication with an internal flow path, and the ground improvement material is supplied from the spout 12d to the first excavation blade. It is configured to be injected radially outward with the rotation of 12 and mixed with excavated soil.

As shown in FIG. 1, the first rotating shaft 11 and the second rotating shaft 13 are provided with stirring blades 19 that rotate together with the rotating shafts 11 and 13 at predetermined positions in the axial direction of the rotating shafts 11 and 13, respectively. It has been. The stirring blades 19 each have a shape in which a plurality of blades extend radially outward, and a range between the first connecting shaft 18A provided at the lowermost portion and the second connecting shaft 18B provided second from the bottom. Is provided. And the stirring blade 19 provided in the 1st rotating shaft 11 and the stirring blade 19 provided in the 2nd rotating shaft 13 are arrange | positioned in the position shifted | deviated to the up-down direction so that it may not mutually interfere.
As shown in FIG. 3, the central rotating shaft 11B that supports the central excavating blade 12B is coaxial with the stirring blade 19A that rotates together with the central rotating shaft 11B at the same height as the excavating blades 12A and 12C on both sides. Is provided.

As shown in FIG. 2, the side cutters 15 are arranged on both sides of the lowermost first connecting shaft 18 </ b> A in the thickness direction Z of the ground excavator 1, and the connecting member 20 is connected to the first connecting shaft 18 </ b> A. Is supported through. As shown in FIG. 4B, the side cutter 15 includes a ground improvement region M0 surrounded by a common circumscribing line T of the rotation trajectory excavated by the plurality of first excavation blades 12A to 12C, and the ground improvement region. It is located in the 2nd excavation area | region M2 between the 1st excavation area | region M1 (refer Fig.4 (a)) excavated by the 1st excavation blade 12 and the 2nd excavation blade 14 among M0.
On the inner surface side, the side cutter 15 is formed with an inclined surface gradually toward the vertical surface including the common circumscribing line T as it goes from the central portion to the outer peripheral portion in plan view, and further, the side cutter 15 is formed in a shape in which the lower end side is tapered. Has been.

  As shown in FIG. 6, the support frame 16 rotatably supports the upper end 11 a of the first rotary shaft 11 and the upper end 13 a of the second rotary shaft 13, and a pin or the like is attached to the tip 21 a of the arm 21 of the work machine 2. A drive motor (not shown) that is connected by a detachable connecting means and applies rotational power to the rotary shafts 11 and 12 is provided inside.

Next, the ground improvement method using the ground improvement apparatus 1 mentioned above is demonstrated.
As shown in FIG. 5, the ground improvement device 1 is used as an attachment of the work machine 2 such as a backhoe, and the support frame 16 is attached to the tip 21 a of the arm 21 of the work machine 2. Then, after the ground improvement device 1 is installed on the ground to be improved, the working machine 2 applies a downward force in the vertical direction to the ground improvement device 1 to take the excavation reaction force, and together with the first excavation blades 12A, 12B, 12C The second excavation blades 14A and 14B are rotated to excavate the ground in the first excavation area M1 shown in FIG. 4A, and further, the ground in the second excavation area M2 shown in FIG. The ground improvement region M0 is formed by cutting the material so as to drop.

  In addition, the ground improvement material is injected toward the ground from the injection port 12d of the first excavation blade 12 shown in FIG. 1 to the excavated soil excavated in the first excavation region M1 and the second excavation region M2, and the first rotating shaft The excavated soil is uniformly and effectively mixed and stirred by the agitating blades 19A provided directly above the central excavating blades 12B and the plural agitating blades 19 provided on the first and second rotating shafts 13.

  Since the ground improvement device 1 according to the present embodiment has a simple structure as described above and can be downsized, it can be used as an attachment for the work machine 2 such as a backhoe (see FIG. 5). . Therefore, even in a narrow space, the ground improvement device 1 can be introduced to form the ground improvement regions K1 and K2 shown in FIG.

Next, the operation of the ground improvement device 1 described above will be specifically described based on the drawings.
In the ground improvement device 1, the central excavation blade 12 </ b> B provided at the lower end of the central rotation shaft 11 </ b> B among the three first rotation shafts 11 provided protrudes to a lower position than the other excavation blades 12 </ b> A and 12 </ b> C. Since the center portion of the excavation cross section by the ground improvement device 1 is excavated in advance, it is possible to suppress the loosening of the surrounding ground around the area excavated by the central excavation blade 12B, and stable excavation. It can be performed.

  As shown in FIG. 6 (a), in the ground improvement device 1, the position of the center of gravity J of the device is the position of the central excavation blade 12 </ b> B and the center in the width direction of the device 1. Therefore, when the ground improvement wall is constructed by continuous construction, as shown in FIG. 6B, excavation and improvement are performed by overlapping a part of the subsequent ground improvement region K2 with respect to the preceding ground improvement region K1. However, the load applied to the ground on the excavation surface adjacent to the preceding ground improvement region K1 (corner ground Ga) can be reduced. Therefore, since it becomes possible to prevent the ground ga of the corner from loosening, the corner is collapsed to the preceding ground improvement region K1 side, and the ground improvement device 1 is inclined to the preceding ground improvement region K1 side. Therefore, the ground improvement device 1 can be excavated and improved in a posture directed in the vertical direction Y without being inclined, and the quality of the ground improvement wall can be ensured.

Further, as shown in FIG. 6A, the center of gravity J of the apparatus 1 is located on the central excavation blade 12B located at the center in the width direction of the apparatus 1, and the tip of the central excavation blade 12B is on the ground surface Gb at the beginning of excavation. Since it is inserted, it can suppress that the ground improvement apparatus 1 shakes and moves in a horizontal direction, or tilts.
Furthermore, by performing the preliminary excavation with the central excavation blade 12B, the ground around the advanced ground improvement region K1 is loosened, and the rotational torque of the excavation blades 12A and 12C provided on both sides of the central excavation blade 12B can be reduced. As a result, the torque required for the entire apparatus can be reduced, the capacity of the drive equipment can be suppressed, the cost can be reduced, and the weight and size of the apparatus can be reduced.

  Further, as shown in FIG. 3, the excavation blades 12A and 12C on both sides are arranged in a slack area α surrounded by a range inclined at an angle of 45 degrees obliquely upward from the outer peripheral edge 12c of the central excavation blade 12B. The loose ground can be efficiently excavated by the excavating blades 12A and 12C on both sides.

  Further, since the stirring blade 19A provided coaxially with the central rotating shaft 11B for rotating and supporting the central excavating blade 12B is provided at the same height as the excavating blades 12A and 12C on both sides, the excavating blades 12A and 12C on both sides are provided. It is possible to eliminate a portion where the earth and sand excavated by the central excavation blade 12B are not agitated between them and at a position above the central excavation blade 12B. That is, since the earth and sand can be evenly stirred even at the height positions of the excavating blades 12A and 12C on both sides, it is possible to suppress an increase in rotational torque due to poor stirring around the central rotary shaft 11B of the central excavating blade 12B. .

  As described above, the ground improvement device according to the present embodiment can prevent the device from being tilted, stabilize the excavation ground, and reliably excavate in the vertical direction.

As mentioned above, although embodiment of the ground improvement apparatus by this invention was described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning.
For example, in the present embodiment, three first rotary shafts 11A to 11C are provided, and the central excavation blade 12B provided on the central rotary shaft 11B located in the center of the first rotary shafts 11A to 11C is configured to protrude downward. It is not limited to. For example, the first rotary shaft is five, the configuration of the first excavating blades arranged in the center to project downward, the center of the five first excavating blades is the lowest stage, You may make it provide a level | step difference in the position of a 1st excavation blade so that it may be located upwards sequentially toward both sides. As described above, the number of the first rotary shafts provided with the first excavating blades is three or more and can be set to an appropriate number.

  Further, the downward projecting length with respect to the excavation blades 12A and 12C on both sides of the central excavation blade 12B is preferably a region surrounded by a range obliquely upward 45 degrees from the outer peripheral edge 12c of the central excavation blade 12B with respect to the horizontal plane. Although it is α, it is not limited to be in the range of this region α. In short, the central excavation blade only needs to be provided at a position below the other excavation blades arranged on both sides thereof.

  Furthermore, the configuration such as the size, arrangement, shape, and quantity of the side cutter 15, the connecting shaft 18, and the stirring blade 19 can be appropriately set according to the geology of the ground to be improved, the excavation speed, and the like. Also, these can be omitted.

Moreover, although the ground improvement apparatus 1 by this Embodiment is used as an attachment attached to work machines 2, such as a backhoe, it is not restrict | limited to such a usage form, For example, on a special stand It can also be installed and used.
In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Ground improvement apparatus 2 Working machine 11, 11A, 11C 1st rotating shaft 11B Central rotating shaft (1st rotating shaft)
12, 12A, 12C First excavation blade 12B Central excavation blade (first excavation blade)
13, 13A, 13B Second rotating shaft 14, 14A, 14B Second excavation blade 16 Support frame 18 Connection shaft 19, 19A Stirring blade J Center of gravity M0 Ground improvement region M1 First excavation region M2 Second excavation region T Common external tangent

Claims (3)

A ground improvement device that moves the ground and improves the ground,
At least three rotating shafts rotating around a vertical axis and arranged parallel to each other;
A drilling blade fixed to the lower end of the rotary shaft and rotating horizontally;
With
Of the excavating blades arranged in the horizontal direction, the central excavating blade disposed in the center is provided at a position below the other excavating blades disposed on both sides thereof. .   2. The ground improvement device according to claim 1, wherein the other excavation blades are provided in a region surrounded by a range of 45 degrees obliquely upward with respect to a horizontal plane from an outer peripheral edge of the central excavation blade. .   The rotating shaft that supports the central excavating blade is provided with an agitating blade that rotates together with the rotating shaft at the same height as the excavating blades on both sides. The ground improvement device described in 1.

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