JP2012251398A - Agitating device for soil improvement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agitating device for soil improvement capable of reliably and efficiently agitating and mixing excavated soil and soil improving materials.SOLUTION: An agitating device for soil improvement 20 includes a front side v-shaped agitating blade 22 and a rear side v-shaped agitating blade 23 attached to an excavation shaft 21 in an inverted state. During soil excavation, excavated soil and soil improving materials are agitated and mixed mainly by the front side v-shaped agitating blade 22. The excavated soil entering inside the front side v-shaped agitating blade 22 is agitated by a horizontally agitating blade 24 arranged at the rear side thereof. When pulling out the agitating device for soil improvement 20, the excavated soil and the soil improving materials agitated and mixed by the front side v-shaped agitating blade 22 are agitated and mixed again by the rear side v-shaped agitating blade 23. Also in this case, the excavated soil entering inside the rear side v-shaped agitating blade 23 is agitated by the horizontally agitating blade 24. Reliable and efficient soil improvement work can be performed by agitating and mixing in a reciprocated manner.

Description

  The present invention relates to an agitation device for ground improvement in which a ground improvement material is injected while excavating the ground to be improved, and the excavated soil and the ground improvement material are agitated and mixed.

  In order to stabilize soft ground such as cohesive soil, sandy soil, silt, gravel soil, loam, etc., ground improvement material (stabilizer), for example, cementitious slurry, is soft ground while excavating the soft ground vertically. There is known a ground improvement method in which it is injected into the ground and mixed with stirring. This ground improvement method is widely used, for example, to improve the foundation ground of structures, prevent slippage and collapse of slopes such as natural slopes and embankment slopes, create support ground for building foundations, prevent liquefaction, and strengthen foundations. It is used.

  In this ground improvement method, a stirring device is attached to the lower end of a rotating shaft that is vertically supported at the tip of a boom of a crane or other work machine, and ground improvement material is injected into the excavated soil from the tip of the stirring device while excavating the ground. At the same time, the ground improvement material and excavated soil are stirred and mixed by the stirring blades of the stirring device. As the stirring device, as disclosed in Patent Documents 1 to 3, a plurality of horizontal stirring blades having a drilling bit at the tip of the drilling shaft (rotating shaft) and extending in the radial direction from the outer periphery of the drilling shaft are provided. What you have is known.

JP 2003-64660 A JP 2003-13438 A JP 2011-69093 A

  Here, when using a stirrer equipped with such a horizontal stirrer blade, the ground improvement material and excavated soil may not be sufficiently stirred and mixed. For example, the excavated soil located between the horizontal agitating blades may not be sufficiently crushed by the horizontal agitating blade, and the ground improvement material and the excavated soil may not be sufficiently agitated and mixed. For this reason, it is necessary to repeat the excavation and extraction operations of the stirring device at the same excavation position, and there is a problem to be solved that the excavated soil and the ground improvement material cannot be efficiently stirred and mixed.

  In view of this point, an object of the present invention is to propose a ground improvement stirrer that can reliably and efficiently stir and mix excavated soil and ground improvement material.

In order to solve the above problems, the ground improvement stirring device according to the present invention is:
A hollow excavation shaft, and a front V-shaped stirring blade, a rear V-shaped stirring blade and a horizontal stirring blade attached to the drilling shaft,
A discharge port for ground improvement material is formed on the outer peripheral surface of the tip of the excavation shaft in the ground excavation direction,
The front V-shaped agitating blade, when viewed from a direction perpendicular to the excavation axis, is tapered toward the ground excavation direction of the excavation axis, and has a V-shape with the central axis of the excavation axis as a symmetric axis. ,
When viewed from the direction perpendicular to the excavation axis, the rear V-shaped agitating blade tapers in the extraction direction in which the excavation axis is extracted from the ground, and has a V-shape with the central axis of the excavation axis as the axis of symmetry. And
The rear V-shaped stirring blade is disposed on the side in the drawing direction with respect to the front V-shaped stirring blade,
The horizontal stirring blade is characterized in that it extends from both sides of the drilling shaft in a direction perpendicular to the drilling shaft between the front V-shaped stirring blade and the rear V-shaped stirring blade on the drilling shaft.

  The ground improvement stirring device of the present invention includes a pair of front V-shaped stirring blades and rear V-shaped stirring blades attached to the excavation shaft in the reverse direction. During ground excavation, the excavated soil and ground improvement material are agitated and mixed mainly by the front V-shaped agitating blade. Further, the excavated soil that has entered the inside of the front V-shaped stirring blade is stirred by the horizontal stirring blade disposed on the rear side. Next, when the stirring device is pulled out, the excavated soil and the ground improvement material stirred and mixed by the front V-shaped stirring blade are again stirred and mixed by the rear V-shaped stirring blade located on the side in the pulling direction. Also in this case, the excavated soil that has entered the inside of the rear V-shaped stirring blade is stirred by the horizontal stirring blade.

  Thus, since a pair of reverse V-shaped stirring blades are provided, the same stirring and mixing performance is exhibited in both strokes during excavation and extraction. That is, reliable and efficient ground improvement work by reciprocating stirring and mixing can be performed. Further, the V-shaped stirring blade has higher stirring and mixing performance than the horizontal stirring blade. Therefore, compared with the conventional stirring apparatus, stirring and mixing of the excavated soil and the ground improvement material can be performed reliably and efficiently.

  Here, a plurality of excavating bits are fixed to the excavation side surface portion facing the ground excavation direction in the front V-shaped agitating blade in a state facing the excavating direction and the like, and the pulling direction in the rear V-shaped agitating blade is directed to It is desirable that a plurality of excavation bits be fixed in a state in which the drawing side surface portion faces the drawing direction or the like. The excavated soil that has not been crushed at the time of excavation is reliably pulverized by the backward excavation bit at the time of pulling, and the excavated soil and the ground improvement material can be reliably agitated and mixed.

  Further, it is desirable that the front V-shaped stirring blade and the rear V-shaped stirring blade are connected to each other so as to have a rectangular shape when viewed from a direction orthogonal to the excavation axis. In this way, the excavated soil can be pulverized and mixed more reliably than when the front V-shaped agitating blade and the rear V-shaped agitating blade are separated in the axial direction of the excavating shaft. Further, the strength and rigidity of these stirring blades can be increased, and there are advantages such as improved durability.

It is a layout showing an example of ground improvement equipment provided with a ground improvement stirring device according to the present invention. (A) is a side view which shows the stirring apparatus for ground improvement of FIG. 1, (b) is a side view at the time of seeing from the direction orthogonal to (a). It is explanatory drawing which shows the flow of construction in the case of performing ground improvement using the stirring apparatus for ground improvement. It is explanatory drawing which shows the columnar improvement procedure in the case of improving a ground into a columnar shape using the ground improvement stirring apparatus. It is explanatory drawing which shows the whole surface improvement procedure in the case of improving the whole surface of a ground using the stirring apparatus for ground improvement.

  Embodiments of a ground improvement agitation apparatus to which the present invention is applied will be described below with reference to the drawings.

  With reference to FIG. 1, an example of the ground improvement equipment provided with the ground improvement stirring apparatus will be described. As shown in this figure, the ground improvement equipment includes a ground improvement material supply plant 1 installed on a site near the ground surface G to be improved, and the ground to be improved upon receiving the supply of the ground improvement material from here. An improved construction machine 2 for improving the surface G is provided.

  The plant 1 supplies, for example, a slurry obtained by mixing a cement-based solidified material with water as a ground improvement material, and includes a cement silo 3, a water tank 4, a batcher plant 5, a grout pump 6, and a generator 7. Slurry is supplied from the discharge port of the grout pump 6 to the improved construction machine 2 through the supply pipe 8. The improved construction machine 2 includes a general-purpose backhoe 11, a rotary drive mechanism 12 that can be attached to the boom tip of the backhoe 11, and a hollow rotary shaft 13 that is rotationally driven while being vertically supported by the rotary drive mechanism 12. The ground improvement stirring device 20 is provided.

  The structure of the ground improvement stirring device 20 will be described with reference to FIG. The ground improvement stirrer 20 (hereinafter sometimes simply referred to as “stirrer 20”) includes a hollow excavation shaft 21 that is connected and fixed coaxially to the lower end of the rotary shaft 13. A front side V-shaped stirring blade 22, a rear side V-shaped stirring blade 23, and a horizontal stirring blade 24 are fixed to the shaft 21 by welding or the like.

  A slurry discharge port 25 is formed on the outer peripheral surface of the tip of the excavation shaft 21 in the ground excavation direction A. The slurry supplied from the plant 1 side through the supply pipe 8 is discharged through a supply path (not shown) formed in the hollow portion of the hollow rotary shaft 13 and the hollow portion of the hollow excavation shaft 21. And is sprayed to the outside from here.

  As can be seen from FIG. 2A, the front V-shaped agitating blade 22 is tapered toward the ground excavation direction A of the excavation shaft 21 when viewed from the direction orthogonal to the excavation shaft 21. The center axis 21a is a V-shaped with the symmetry axis. On the other hand, the rear V-shaped stirring blade 23 is fixed to the excavation shaft 21 in the reverse direction. That is, when viewed from the direction orthogonal to the excavation shaft 21, the V-shape is tapered toward the extraction direction B in which the excavation shaft 21 is extracted from the ground, and the central axis 21a of the excavation shaft 21 is a symmetric axis. ing.

  In addition, the rear V-shaped stirring blade 23 is located on the side in the drawing direction B with respect to the front V-shaped stirring blade 22. In this example, both ends of the front V-shaped stirring blade 22 and both ends of the rear V-shaped stirring blade 23 are connected to each other and have a rectangular shape when viewed from the direction perpendicular to the excavation shaft 21.

  On the other hand, the horizontal stirring blade 24 is located between the front V-shaped stirring blade 22 and the rear V-shaped stirring blade 23 in the excavation shaft 21. Further, with the excavation shaft 21 as a center, the excavation shaft 21 extends from both sides of the excavation shaft 21 in a symmetric state in a direction perpendicular to the excavation shaft 21.

  Here, a plurality of excavation bits (conical bits) 26 are fixed to the excavation side surface portion of the front V-shaped stirring blade 22 facing the ground excavation direction A by welding or the like in a state mainly facing the ground excavation direction A side. Has been. Similarly, a plurality of excavation bits (conical bits) 27 are fixed to the drawing side surface portion of the rear V-shaped stirring blade 23 facing the drawing direction B side by welding or the like mainly in the drawing direction B. ing.

  In this example, one front V-shaped agitating blade 22 and one rear V-shaped agitating blade 23 are provided, but two or more front sides at different positions in the axial direction of the excavation shaft 21 are provided. A V-shaped stirring blade 22 can be disposed. Similarly, two or more rear V-shaped stirring blades 23 may be arranged at different positions in the axial direction of the excavation shaft 21. In the case where a plurality of front V-shaped stirring blades 22 and a plurality of rear V-shaped stirring blades 23 are arranged, for example, the front V-shaped toward the drawing direction B from the portion of the excavation shaft 21 on the tip side in the digging direction A. The stirring blades 22 and the rear V-shaped stirring blades 23 may be alternately arranged. It is also possible to arrange a plurality of horizontal stirring blades 24 on the excavation shaft 21. For example, the horizontal stirring blades 24 may be arranged between the adjacent front V-shaped stirring blades 22 and rear V-shaped stirring blades 23, respectively.

  Next, with reference to FIG. 3, an example of the construction procedure of the ground improvement work using the stirring device 20 will be described. First, as shown in FIG. 3A, the improvement range 31 is positioned on the ground surface G to be improved. Next, as shown in FIG. 3B, the ground surface in the improved range 31 is excavated to the improved top 32 using a general-purpose backhoe 11. Thereafter, as shown in FIG. 3 (c), the rotary drive mechanism 12, the rotary shaft 13 and the stirring device 20 are attached to the tip of the boom of the backhoe 11, and the stirring device 20 discharges the slurry, and within the improved range 31. The ground part is homogeneously stirred and mixed. After injecting the slurry into the ground portion in the improved range 31 and stirring and mixing, the top level of the ground portion in the improved range 31 is adjusted by the backhoe 11 as shown in FIG.

  An example of the ground improvement work shown in FIG. 3C will be described with reference to FIG. The ground improvement work shown in this figure is a work for improving the ground into a columnar shape, and as shown in FIG. 4A, the columnar part set in the improvement range 31, for example, 4 set in the rectangular improvement range 31. The tip of the excavating shaft 21 of the stirring device 20 is set from the upper side with respect to one columnar portion 41 of the two columnar portions 41 to 44, and the stirring device 20 is rotated at a low speed to improve the bottom surface of the improved range 31 in the depth direction. Excavate to 33. After reaching the improved bottom surface 33, the stirring device 20 is pulled up to the improved top end 32 while rotating at high speed (for example, rotating at a rotational speed twice as high as that during excavation). Further, with the high-speed rotation, the stirring device 20 is dug from the improved top 32 to the improved bottom surface 33 and then pulled up to above the improved top 32.

  Thereafter, as shown in FIG. 4 (b), the diagonal corner column 43 in the improved range 31 is improved by the same operation, and next, as shown in FIG. The columnar portion 44 located at the corner to be improved is improved, and finally the columnar portion 42 of the remaining corner is improved as shown in FIG. As a result, as shown in FIG. 4E, a state in which almost the entire improved range 31 is improved into a columnar shape is formed.

  On the other hand, in the entire improvement work of the improved range 31 shown in FIG. 5, as shown in FIGS. 4 (a) to 4 (d), as shown in FIGS. 5 (a) to 5 (d). Make improvements to the column. After that, as shown in FIG. 5E, the space between the columnar portions 41 to 44 is improved so that there is no unimproved portion between the columnar portions 41 to 44. Thereby, as shown in FIG.5 (f), the whole improvement range 31 will be in the improved state.

  As described above, the stirring device 20 used in this example includes the pair of front V-shaped stirring blades 22 and rear V-shaped stirring blades 23 attached to the excavation shaft 21 in the reverse direction. Therefore, during ground excavation, the excavated soil and the slurry are mainly stirred and mixed by the front V-shaped stirring blade 22. The excavated soil that has entered the inside of the front V-shaped agitating blade 22 is pulverized by the horizontal agitating blade 24 disposed on the rear side and stirred and mixed with the slurry.

  When the stirring device 20 is pulled out, the excavated soil and the slurry stirred and mixed by the front V-shaped stirring blade 22 are mainly stirred and mixed again by the rear V-shaped stirring blade 23 located on the side in the drawing direction B. . Also in this case, the excavated soil that has entered the inside of the rear V-shaped stirring blade 23 is pulverized by the horizontal stirring blade 24 and stirred and mixed with the slurry.

  Thus, since the stirring device 20 is provided with the V-shaped stirring blades 22 and 23 in the opposite directions, the same stirring and mixing performance is exhibited in both the excavation and the drawing strokes. Further, the V-shaped stirring blades 22 and 23 have higher stirring and mixing performance than the horizontal stirring blades. Therefore, compared with the conventional stirring apparatus, stirring and mixing of the excavated soil and the ground improvement material can be performed reliably and efficiently. As a result, a good improved ground can be obtained.

  A plurality of excavation bits 26 are fixed to the excavation side surface portion of the front V-shaped agitating blade 22 facing the ground excavation direction, and the pulling is directed to the extraction direction of the rear V-shaped agitating blade 23. A plurality of excavation bits 27 are also fixed to the side surface portion. Therefore, since the excavated soil that has not been crushed during excavation is reliably pulverized by the excavation bit 27 during extraction, the excavated soil and the ground improvement material can be reliably agitated and mixed.

  On the other hand, the improved construction machine of this example uses a general-purpose backhoe 11 and can move the boom in the vertical direction and the horizontal direction. Therefore, the agitating and mixing operation of the excavated soil and slurry can be performed while moving the agitating device 20 attached here in any direction within the improved range 31, and therefore the entire surface shown in FIG. 5 together with the columnar improvement work shown in FIG. Improvement work is easy and convenient.

DESCRIPTION OF SYMBOLS 1 Plant 2 Improvement construction machine 3 Cement silo 4 Water tank 5 Batcher plant 6 Grout pump 7 Generator 8 Supply pipe 11 Backhoe 12 Rotation drive mechanism 13 Rotating shaft 20 Ground improvement stirrer 21 Excavation shaft 21a Center axis 22 Front V-shaped stirring Blade 23 Rear V-shaped stirring blade 24 Horizontal stirring blade 25 Discharge port 26 Drilling bit 27 Drilling bit 31 Improved range 32 Improved top end 33 Improved bottom surface 41 to 44 Column A A Excavation direction B Extraction direction G Ground surface

Claims (3)

A ground improvement stirring device that injects ground improvement material while excavating the target ground and stirs and mixes the excavated soil and ground improvement material,
A hollow excavation shaft, and a front V-shaped stirring blade, a rear V-shaped stirring blade, and a horizontal stirring blade attached to the drilling shaft,
The discharge port of the ground improvement material is formed on the outer peripheral surface of the tip portion in the ground excavation direction in the excavation shaft,
The front V-shaped agitating blade, when viewed from a direction orthogonal to the excavation axis, tapers in the ground excavation direction of the excavation axis, and has a V-shape with the central axis of the excavation axis as the symmetry axis. And
The rear V-shaped agitating blade, when viewed from a direction orthogonal to the excavation axis, tapers in the extraction direction in which the excavation axis is extracted from the ground, and has a V-shape with the central axis of the excavation axis as the symmetry axis Has a shape,
The rear V-shaped stirring blade is arranged at a position on the side in the drawing direction with respect to the front V-shaped stirring blade,
The horizontal agitating blade extends in a direction perpendicular to the excavation axis from both sides of the excavation shaft at a position between the front V-shaped agitating blade and the rear V-shaped agitating blade on the excavation shaft. A stirrer for ground improvement. In claim 1,
A plurality of excavation bits are fixed to the excavation side surface portion facing the ground excavation direction in the front V-shaped stirring blade,
A ground improvement stirring device, wherein a plurality of excavation bits are also fixed to a drawing side surface portion of the rear side V-shaped stirring blade facing the drawing direction. In claim 1 or 2,
The ground improvement stirrer characterized in that the front V-shaped stirring blade and the rear V-shaped stirring blade are connected to each other and have a rectangular shape when viewed from a direction perpendicular to the excavation axis.