JP4566805B2 - Ground improvement device and ground improvement method - Google Patents

Description

The present invention relates to a ground improvement device and a ground improvement method using the device .

  Conventionally, as one form of the ground improvement device, a drilling blade body is provided at the lower end portion of the drilling shaft body extending in the vertical direction, and a stirring blade body is provided on the outer peripheral surface of the drilling shaft body located above the drilling blade body. The excavating blade body excavates the ground, and the excavated soil is agitated by the agitating blade body while discharging the solidifying material from the solidifying material discharging portion provided at a predetermined location, and the solidified material and the excavated soil and There is one in which the ground is improved by kneading and solidifying (see, for example, Patent Document 1).

The sand compaction pile method is used as a compacting method for sandy ground, and this method allows the casing pipe to penetrate into the ground using a forced lifting device and a rotary press-fitting device, and sand is passed through the casing pipe. The ground is compacted by creating a pile that is pressed into the ground and compacted.
JP-A-3-63312

  However, in the ground improvement device described above, when the soil excavated by the excavating blade body is kneaded with the solidified material discharged from the solidified material discharge unit while being stirred by the stirring blade body, it is supplied into the excavation hole ( In proportion to the amount of solidified material discharged, a part of the excavated soil may be carried out from the excavation hole to the ground, but if such soil is not smoothly carried out, As a result, the surrounding surface of the excavation hole is displaced outward (lateral displacement), which adversely affects the existing underground structures around the soil improvement ground. It causes problems such as impact and the ground surface rising.

  In addition, when the sand compaction pile method is used for compacting sandy ground, there is a problem in that the surroundings are adversely affected due to large vibration and noise.

Therefore, in the present invention, the excavation blade body is provided at the lower end portion of the excavation shaft body extending in the vertical direction, the agitating blade body is provided on the outer peripheral surface of the excavation shaft body located above the excavation blade body, and the excavation blade The ground was excavated by the body, and the solidified material and ground improver were discharged from the discharge part provided at a predetermined place while stirring the excavated soil with the stirring blade body, and the solidified material and ground improver were excavated. In the ground improvement device adapted to improve the ground by kneading with soil, a soil carry-in / out wing body is provided on the outer peripheral surface of the excavation shaft body, and the soil carry-in / out wing body is driven up and down by a lifting means・ The upper end of the support is linked to the support, independent of the excavation shaft, and can be driven in the forward / reverse rotation or rotation stopped around the axis of the excavation shaft. along without movable up and down movement, the soil loading and unloading the wing-body, boring into the ground It also also provides a soil improvement apparatus characterized in that without the also possible to excavation in the ground by independently of the drilling shaft arranged above the surface of the ground that.

Further, in the present invention, a drilling blade body is provided at a lower end portion of a drilling shaft body that extends in the vertical direction, and a stirring blade body is provided on an outer peripheral surface of the drilling shaft body located above the drilling blade body. The ground was excavated by the body, and the solidified material and ground improver were discharged from the discharge part provided at a predetermined place while stirring the excavated soil with the stirring blade body, and the solidified material and ground improver were excavated. In the ground improvement device adapted to improve the ground by kneading with soil, a soil carry-in / out wing body is provided on the outer peripheral surface of the excavation shaft body, and the soil carry-in / out wing body is independent of the excavation shaft body. It is possible to rotate forward and backward around the axis of the excavation shaft body, and it can be moved up and down along the excavation shaft body. Each part is attached to the excavation shaft body, and the middle part is formed to bulge outward. A horizontal component force generator in the radial direction centered on the excavation shaft is provided in the middle, and the horizontal component force in the radial direction from the stirring force of the stirring blade body to the excavated soil is generated by the horizontal component generating unit. It is intended to provide a ground improvement device characterized by the fact that the above is generated.
Further, the present invention is a ground improvement method for performing ground improvement work by the ground improvement device according to claim 1, wherein the soil carry-in / out wing body is disposed above the excavation shaft body by the lifting means. A step of kneading the soil excavated by the excavation blade body with the solidified material discharged from the discharge unit while stirring by the relative agitating blade body; Along with the increase of soil and solidified material in the hole, the peripheral surface of the excavation hole is displaced outward, and the underground displacement detection means disposed in the vicinity of the excavation hole is displaced beyond the predetermined allowable displacement amount. When the amount is detected, the excavation shaft body is lifted upward by the required width, and in this state, the soil carry-in / out wing body disposed at the upper part of the excavation shaft body is moved to the vicinity of the ground surface by the lifting means. The process of lowering and digging while rotating the excavation shaft forward In both cases, a part of the excavated soil is forcibly carried out to the ground by the soil carry-in / out wing body by excavating the soil carry-in / out wing body while being rotated forward by the drive / support. The process of suppressing the outward displacement of the peripheral surface of the drilling hole due to the increase in soil and solidified material within the allowable range and excavating and stirring work to a predetermined depth, A ground improvement method characterized by having a step of kneading excavated soil and a solidified material with a relative stirring blade body and a step of solidifying the kneaded soil and the solidified material by pulling up while being inverted is provided. Is.
Further, the present invention is a ground improvement method for performing ground improvement work by the ground improvement device according to claim 1, wherein the length of the soil carry-in / out wing body is solidified before the ground improvement work is started. The step of setting the length to reach the depth where unnecessary soil exists, which significantly reduces the solidification effect of the material, and the excavation blade body provided at the lower end of the excavation shaft body extending in the vertical direction The excavated soil is agitated by a relative agitating blade provided on the outer peripheral surface of the excavating shaft, and the soil carry-in / out wing is driven to rotate forward by the drive / support, The step of carrying out a part of the excavated soil to the ground and the excavation / stirring operation and the soil removal operation are continued until the lower end of the soil carrying-in / out wing body reaches the unnecessary soil, and the unnecessary in the excavation hole Unnecessarily soil to the ground and deeper than the unwanted soil After confirming that the soil has been transported to the ground, the step of stopping the forward rotation drive of the soil carry-in / out wing body and the discharge of the solidified material from the discharge section while the soil carry-in / out wing body is in a rotation stopped state The excavated soil and the solidified material are kneaded with a relative agitating blade body, and excavated and agitated to a predetermined depth, and then the excavated shaft body is pulled up while being inverted to solidify with the excavated soil. The present invention provides a ground improvement method comprising a step of kneading a material with a relative stirring blade body and a step of solidifying the kneaded soil and the solidified material .

(1) In the present invention described in claim 1, the excavation blade body is provided at the lower end portion of the excavation shaft body extending in the vertical direction, and the stirring blade body is provided on the outer peripheral surface of the excavation shaft body located above the excavation blade body. The excavating blade body excavates the ground, and the solidified material or ground improving agent is discharged from the discharge portion provided at a predetermined location while stirring the excavated soil with the stirring blade body. in soil improvement apparatus that performs ground improvement by kneading the drilled as modifiers soil, provided with a soil loading and unloading the blade body on the outer peripheral surface of the drilling shaft, the soil loading and unloading the blade body is lifting The upper end portion is interlocked and connected to the driving / supporting body that is lifted / lowered by means, independently of the excavation shaft body, and can be driven forward / reverse rotation around the axis of the excavation shaft body or held in a rotation stopped state , and The soil can be moved up and down along the excavation shaft body, It is possible to arrange it above the surface of the ground independently of the excavation shaft that digs into the ground, or to dig into the ground .

  In this way, when the soil excavated by the excavating blade body is kneaded with the solidified material and ground improvement agent discharged from the discharge unit while being stirred by the stirring blade body, the discharged solidified material and ground improvement are discharged. A part of the soil excavated in proportion to the amount of the agent may be carried out from the excavation hole to the ground, but if the soil is not smoothly carried out, the soil carrying-in / out wing is rotated forward. Thus, a part of the excavated soil can be forcibly carried out to the ground.

  Therefore, when the solidification material or ground improvement agent is supplied (discharged) into the excavation hole and the contents (soil and solidification material) in the excavation hole increase, the displacement of the outer surface of the excavation hole to the outside ( Lateral displacement) can be suppressed within an allowable range.

  As a result, it is possible to reliably prevent the occurrence of problems such as adversely affecting existing underground structures provided around the soil-improved ground and the ground surface rising.

  Moreover, since the amount of soil carried out can be adjusted by appropriately adjusting the rotation speed of the soil carrying-in / out wing body, it is possible to prevent the formation of voids and cavities in the ground due to soil carrying-out. Unloading work can be performed.

  Therefore, assuming that voids and cavities are generated, it is not necessary to supply the solidifying material and the ground improvement agent in excess of the set amount, and the cost of the solidifying material and the ground improvement agent can be reduced.

  In addition, when there is a need to compact the ground, sand, crushed stones, or Recycled materials (recycled crushed stone, converter slag, etc.) can be carried into the excavation hole from the ground, and a cylindrical ground improvement pile body compacted in the ground can be created. As a result, the ground is forcibly consolidated. As a result, the earth bearing capacity can be increased as a whole.

  At this time, unlike the sand compaction pile method, a forced elevating device and a rotary press-fitting device for penetrating the casing pipe into the ground are not used, so vibration and noise can be greatly reduced, and adverse effects on the surroundings can be avoided. Can be eliminated.

  In addition, when soil improvement that solidifies, purifies, or neutralizes soil contaminated with harmful substances is made pollution-free, the soil transported from the excavation hole is forced into the excavation hole. It can be carried in while being consolidated.

  This eliminates the need for conventional treatments such as purifying or neutralizing the transported soil or transporting it to a legally permitted designated place and discarding it.

  As a result, it is possible to reduce a large amount of cost for treating the unloaded soil, a cost for transporting the unloaded soil to a designated location, and a cost for dumping to the designated location.

(2) In the present invention described in claim 2 , the excavation blade body is provided at the lower end portion of the excavation shaft body extending in the vertical direction, and the stirring blade body is provided on the outer peripheral surface of the excavation shaft body located above the excavation blade body. The excavating blade body excavates the ground, and the solidified material or ground improving agent is discharged from the discharge portion provided at a predetermined location while stirring the excavated soil with the stirring blade body. In the ground improvement device adapted to improve the ground by kneading the improver and the excavated soil, a soil carry-in / out wing body is provided on the outer peripheral surface of the excavation shaft body, and the soil carry-in / out wing body is excavated. Independent of the shaft body, it can be rotated forward and backward around the axis of the excavation shaft body, and can be moved up and down along the excavation shaft body, and the stirring blade body is extended vertically. At the same time, the upper and lower ends are attached to the excavation shaft body, and the middle part is expanded outward. The horizontal component force generating part in the radial direction centering on the excavation shaft body is provided in the middle part, and the horizontal component force generating part causes the stirring force of the stirring blade body to radial direction with respect to the excavated soil. A horizontal component force is generated.

  In this way, the horizontal component force generating portion provided on the stirring blade body generates a horizontal component force outward from the stirring force of the stirring blade body with respect to the excavated soil. The excavated soil can be forcibly pressed against the peripheral surface for consolidation.

At this time, by rotating the soil loading / unloading wing body in the reverse direction, sand, crushed stone, or recycled material (recycled crushed stone, converter slag, etc.) is carried into the excavation hole from the ground and compacted into the ground. When a columnar ground improvement pile body is created, the ground can be sufficiently forcibly consolidated by the ground improvement pile body, and the ground strength can be greatly increased as a whole.
(3) The present invention described in claim 3 is a ground improvement method for performing ground improvement work by the ground improvement device according to claim 1, wherein the soil carry-in / out wing is moved by the lifting means by the excavating shaft. By disposing on the upper part of the body, the solidified material disposed above the surface of the ground and discharged from the discharge unit while stirring the soil excavated by the excavating blade body by the relative stirring blade body; Along with the increase in the amount of soil and solidified material in the drilling hole and the kneading step, the peripheral surface of the drilling hole is displaced outwardly, and the underground displacement detection means disposed in the vicinity of the drilling hole has a predetermined amount. When a displacement amount greater than the allowable displacement amount is detected, the excavation shaft body is lifted upward by the required width, and in this state, the soil carrying-in / out wing body disposed on the upper portion of the excavation shaft body is lifted / lowered The process of descending to the vicinity of the surface of the ground by While excavating, by excavating while the soil carry-in / out wing body is rotated forward by the drive / support, a part of the excavated soil is forcibly carried out to the ground by the soil carry-in / out wing body, The process of suppressing the displacement to the outside of the perimeter of the excavation hole due to the increase of soil and solidified material in the excavation hole within the allowable range, and excavation and agitation work to a predetermined depth, then excavation The shaft body is pulled up while being inverted, and the excavated soil and the solidified material are kneaded by the relative stirring blade body, and the kneaded soil and the solidified material are solidified.
In this way, the soil carry-in / out wing body is held in the rotation stopped state by the drive / support, so that the excavated soil is not carried out, and the peripheral surface of the excavation hole is surrounded by the excess soil carry-out. It is possible to reliably prevent the occurrence of a problem of collapse due to earth pressure.
(4) The present invention described in claim 4 is a ground improvement method for performing ground improvement work by the ground improvement device according to claim 1, wherein the soil carrying-in / out wing body is started before the ground improvement work is started. The length of the step of setting the length to reach the depth where there is unnecessary soil to significantly reduce the solidification effect of the solidification material, and the lower end of the excavation shaft body extending vertically The ground is excavated by the excavating blade body, the excavated soil is agitated by a relative agitating blade body provided on the outer peripheral surface of the excavating shaft body, and the soil carry-in / out wing body is driven to rotate forward by the drive / support body. And a step of carrying out a part of the soil excavated by the excavating blade body to the ground, and continuing the excavation / stirring work and the soil removing work until the lower end portion of the soil carry-in / out blade body reaches the unnecessary soil, Unloading the unnecessary soil in the excavation hole to the ground and the unnecessary The step of stopping the forward rotation driving of the soil carry-in / out wing body when the soil in the deeper part than the soil has been carried out to the ground, and the discharge part The solidified material is discharged from the ground, the excavated soil and the solidified material are kneaded by the relative stirring blade body, and excavation / stirring work is performed to a predetermined depth. A step of kneading the soil and the solidified material with a relative stirring blade body, and a step of solidifying the kneaded soil and the solidified material.
In this way, in the step of excavating and stirring, for example, when there is unnecessary soil that significantly reduces the solidification effect of the solidifying material, such as a humus soil layer, the step of removing the unnecessary soil in advance In the subsequent step, it is possible to satisfactorily ensure the effect of kneading the solidified material and the excavated soil and chemically solidifying them in the subsequent steps.
The work of kneading and solidifying the solidified material and the excavated soil is performed in a process that does not carry out the soil, so that the waste that the solidified material kneaded with the soil is carried out to the ground does not occur. As a result, the ground improvement work can be performed effectively and efficiently.

  Embodiments of the present invention will be described below with reference to the drawings.

  A shown in FIG. 1 is a ground improvement device according to the present invention, and the ground improvement device A includes a base machine 1 and a solidifying material supply unit 2.

  The base machine 1 includes a self-propelled base machine body 3 provided with a leader 4 extending in the vertical direction. A motor support 5 is attached to the leader 4 so as to be movable up and down, and a drive motor 6 is mounted on the motor support 5. Then, the upper end portion of the excavation shaft body 7 extending in the vertical direction is detachably attached to the drive motor 6 via the counter rotating gear mechanism 8, and the relative stirring blade body 9 is attached to the lower peripheral surface of the excavation shaft body 7. The excavation blade body 10 is attached to the lower end portion of the excavation shaft body 7. Reference numeral 12 denotes a guide body for guiding the excavation shaft body 7 in the excavation direction, and reference numeral 14 denotes an excavation bit provided on the excavation blade body 10.

  A soil carry-in / out wing body 40 is provided on the outer peripheral surface of the excavation shaft body 7, and the soil carry-in / out wing body 40 is provided around the axis of the excavation shaft body 7 independently of the excavation shaft body 7. It is possible to rotate in the reverse direction and to move up and down along the excavation shaft body 7.

  That is, as shown in FIG. 1, a lifting / lowering wire 60 is attached to the reader 4 via lifting / lowering means (not shown), while a driving / supporting body 61 is slidably attached to the reader 4 so The tip of the lifting wire 60 is connected to the body 61, and the driving / supporting body 61 can be moved up and down along the reader 4 via the lifting wire 60 by the lifting means.

  Then, the upper end portion of the soil carry-in / out wing body 40 is interlocked and connected to the drive / support 61, and the soil carry-in / out wing body 40 is driven forward / reversely at a required rotational speed around the axis of the excavation shaft body 7. It is also possible to keep the rotation stopped.

  Here, the soil carrying-in / out wing body 40 extends in the vertical direction to cover the outer peripheral surface of the excavation shaft body 7 and the cylindrical cylindrical support piece 41, and the outer peripheral surface of the cylindrical support piece 41 in the axial direction. And a soil carry-in / out wing piece 42 formed in a spiral shape.

  The solidification material supply unit 2 includes a solidification material storage tank and a solidification material supply pump (not shown), and connects the base end portion of the solidification material supply hose 11 to the solidification material supply pump. Is connected to the excavation shaft body 7 via a swivel joint (not shown).

  As shown in FIGS. 2 and 3, the excavation shaft body 7 is vertically extended so as to surround a cylindrical inner shaft 20 formed by extending in the vertical direction and the outer periphery of the inner shaft 20. The formed cylindrical outer shaft 21 forms an inner / outer double shaft structure, and the inner shaft 20 and the outer shaft 21 are arranged around the same axis via a counter rotating gear mechanism 8 by a driving motor 6. They are designed to rotate in opposite directions.

  A cylindrical body 22 formed by extending in the vertical direction is inserted into the inner shaft 20 to form an inner solidified material supply path 23 in the cylindrical body 22, while the outer periphery of the cylindrical body 22 is formed. An outer solidified material supply path 24 is formed between the surface and the inner peripheral surface of the inner shaft 20.

  Moreover, a communication path (not shown) is formed at the upper end portion of the inner shaft 20, and the inner solidification material supply path 23 and the outer solidification material supply path 24 are communicated with each other via the communication path, thereby solidifying material supply hose. The solidified material supplied through 11 can be divided and supplied to the inner solidified material supply path 23 and the outer solidified material supply path 24.

  Here, the excavation blade body 10 is attached to the lower end portion of the inner shaft 20 via the blade body attachment body 13, and the first solidifying material discharge portion 29 is provided on the blade body attachment body 13.

  And the 1st solidification material discharge part 29 forms the circular 1st solidification material discharge hole 29a in the surrounding wall of the blade body attachment body 13 formed in the cylinder shape, and the 1st solidification material discharge hole 29a is made into the inside solidification material. The solidified material connected to the supply path 23 and supplied through the inner solidified material supply path 23 is discharged directly downward from the first solidified material discharge hole 29a.

  2 and 3, the relative stirring blade body 9 includes an innermost stirring blade 26, an inner stirring blade 27 that rotates the outer periphery of the innermost stirring blade 26 in a relatively opposite direction, The outer periphery of the stirring blade 27 is provided with an outer stirring blade 28 that rotates in a relatively opposite direction, and the inner stirring blade 27 and the outer stirring blade 28 are formed in a substantially similar shape, and both the stirring blades 27, 28 are formed. By making the gap formed between them almost the same width over almost the entire area of both stirring blades 27 and 28, it is possible to prevent the swirling phenomenon of the excavated soil and to exhibit a precise stirring function. I am doing so.

  The innermost stirring blades 26 are formed so as to protrude radially from the lower end of the outer shaft 21, and are provided at a pair of symmetrical positions at the lower end of the outer shaft 21, and rotate in the direction a integrally with the outer shaft 21. Like to do.

  The inner stirring blade 27 is vertically moved between the upper and lower pair of upper and lower horizontal blade pieces 27a and 27b extending in the radial direction of the excavation shaft body 7 and the outer ends of the upper and lower horizontal blade pieces 27a and 27b. The tip of the upper horizontal wing piece 27a is attached to a ring-shaped wing piece support 30 that is formed in an arc shape from the longitudinal wing piece 27c that is extended in the direction and freely fitted to the outer peripheral surface of the outer shaft 21. On the other hand, the tip of the lower horizontal wing piece 27b is attached to the lower end portion of the inner shaft 20 so as to rotate integrally with the inner shaft 20 in the b direction.

  An intermediate horizontal wing piece 27d extending in a straight line in the left-right direction is formed between the central portion of the vertical wing piece 27c and the inner shaft 20, and is solidified in the intermediate horizontal wing piece 27d. An introduction path 33 is formed, and a second solidified material discharge portion 32 (described later) and the outer solidified material supply path 24 are connected through the solidified material introduction path 33.

  In this way, it is possible to increase the stirring efficiency of excavated soil by adding a straight intermediate horizontal blade piece 27d in the left-right direction, and to form the solidified material introduction path 33 in the straight intermediate horizontal blade piece 27d. Thus, the solidified material introduction path 33 can be formed as short and simple as possible, and the processing cost can be reduced.

  Further, a pair of the above-described inner stirring blades 27 is provided at a line-symmetrical position below the inner shaft 20. 31 is a small wing piece formed by projecting outward from the middle part of the vertical wing piece 27c.

  The outer stirring blade 28 is vertically moved between the upper and lower pair of upper and lower horizontal blade pieces 28a and 28b extending in the radial direction of the excavating shaft body 7 and the outer end portions of the upper and lower horizontal blade pieces 28a and 28b. It is formed in an arc shape from the vertical wing piece 28c that is extended in the direction, and the tip of the upper horizontal wing piece 28a is attached to the lower end portion of the outer shaft 21, while the outer peripheral surface of the inner shaft 20 is rotatable. The tip of the lower horizontal wing piece 28b is attached to the loosely fitted ring-shaped wing piece support 34 so as to rotate integrally with the outer shaft 21 in the direction a.

  Three outer stirring blades 28 are provided at regular intervals in the circumferential direction below the excavation shaft body 7. 35 is a small blade piece formed by projecting outward at the upper and lower portions of the vertical blade piece 28c, and the rotation trajectory of these small blade pieces 35, 35 is the small blade piece 31 provided on the inner stirring blade 27. It is arranged so as to overlap the rotation trajectory in the vertical direction, so that the excavated soil can be reliably stirred between the inner and outer stirring blades 27 and 28 that rotate in the opposite directions.

  Further, the inner agitation blade 27 is provided with a second solidifying material discharge portion 32 for discharging the solidifying material, and the second solidifying material discharge portion 32 according to the following will be described.

  That is, as shown in FIGS. 2 and 3, a second solidifying material discharge section 32 is provided at the intersection of the vertical blade piece 27c and the intermediate horizontal blade piece 27d of the inner stirring blade 27, and the second solidifying material is provided. The discharge part 32 forms a second solidified material discharge vertically elongated hole 32a extending in the vertical direction on the back surface of the vertical blade piece 27c (the surface opposite to the surface on the rotation direction side), and the back surface of the intermediate horizontal blade piece 27d. A second solidified material discharge oblong hole 32b extending in the horizontal direction is formed on the surface (the surface opposite to the surface on the rotation direction side), and both the holes 32a and 32b are communicated in a T-shape.

  The second solidified material discharge vertical / horizontal elongated holes 32a and 32b are connected to the outer solidified material supply path 24 through the solidified material introduction path 33 formed in the intermediate horizontal blade piece 27d.

  In this way, when the soft ground G is improved, the leader machine 4 is built by moving the base machine 1 to the ground improvement site, and the excavation shaft body 7 is rotated along the leader 4. By lowering, the ground G is excavated by the excavating blade body 10 and the excavated soil is agitated by the relative agitating blade body 9.

  At this time, the solidification material is supplied from the solidification material supply unit 2 to the solidification material supply hose 11 → the swivel joint → the excavation shaft 7 → the first and second solidification material discharge units 29, 32. The solidified material is discharged from 32, and the solidified material is agitated uniformly in the excavated soil to solidify the excavated soil, thereby building a columnar or wall-shaped ground improvement body in the soft ground G. Thus, the ground G can be improved.

  In particular, the solidified material supplied to the outer solidified material supply path 24 can be discharged from the second solidified material discharge vertical / horizontal holes 32a and 32b of the second solidified material discharge section 32 through the solidified material introduction path 33. The second solidified material discharge vertical hole 32a is formed on the back surface opposite to the rotation direction of the inner stirring blade 27, so that the solidified material can be discharged smoothly and formed in the vertical vertical hole. Therefore, the solidified material can be discharged in the form of a vertically long strip.

  Moreover, since the inner stirring blade 27 rotates and moves in the excavation direction of the excavation shaft body 7, the solidified material film forms a continuous cylindrical film in the circumferential direction and the vertical direction. Solidified material can be evenly arranged in the excavation direction in the excavated soil.

  Further, since the second solidified material discharge oblong hole 32b is formed on the back surface opposite to the rotation direction of the inner stirring blade 27, the solidified material can be discharged smoothly and the horizontal oblong hole in the horizontal direction. Therefore, the solidified material can be discharged in a ring shape.

  Moreover, since the inner stirring blade 27 rotates and moves in the excavation direction of the excavation shaft body 7, the film of the solidified material forms a spiral belt-like film that is continuous in the circumferential direction and the vertical direction. The solidified material can be evenly arranged in the excavation direction in the excavated soil.

  Therefore, in this state, the excavated soil between the stirring blades 27 and 28 is forced to flow in the opposite direction by rotating the inner and outer stirring blades 27 and 28 that are overlapped on the inner and outer sides in opposite directions. Inevitably, the excavated soil can be mixed between the two agitating blades 27 and 28, and the excavated soil can be uniformly kneaded. Since a film can be formed, the excavated soil and the solidified material can be efficiently and uniformly kneaded.

  Here, in the solidified material, small pieces made of synthetic resin are dispersed and mixed in an appropriate amount, so that the small pieces made of synthetic resin can be mixed in the ground improvement body. The horizontal load acting on the improved body effectively functions to strengthen the yield strength against the bending and pulling force generated in the ground improved body, and as a result, the horizontal load resistance of the ground improved body can be increased.

  In the present embodiment, the cross-sectional width of the inner and outer stirring blades 27, 28 is gradually narrowed from the central portions 27e, 28e toward the end surfaces 27f, 27g, 28f, 28g on the rotational direction side. The inner surfaces are tapered surfaces 27h, 27i, 28h, 28i.

  In this way, the soil is excavated by the end face 28f on the rotation direction a side of the outer agitating blade 28, and the inner agitating blade side guide flow smoothly guides the excavated soil along the tapered surface 28h to the inner agitating blade 27 side. The path c can be formed.

  At this time, since the end face 28f on the rotation direction a side of the outer agitating blade 28 is formed with a narrow width, the excavation of the soil can be performed smoothly and reliably, and the excavated soil does not adhere to the end face 28f. Guided to the inner stirring blade 27 side along the side tapered surface 28h.

  As a result, while being excavated by the outer agitating blade 28, the soil guided through the inner agitating blade side guide channel c and the soil excavated by the inner agitating blade 27 are efficiently agitated while relatively reversely rotating. Even when the excavated soil is strong clay, the excavated soil and the solidified material can be efficiently and uniformly kneaded while preventing the excavated soil from becoming a lump.

  In addition, excavation soil is excavated by the end face 27f on the rotation direction b side of the inner stirring blade 27, and an excavation shaft body side guide flow path d for smoothly guiding the excavated soil along the taper surface 27h to the excavation shaft body 7 side. So that it can be formed.

  At this time, since the end face 27f on the rotation direction b side of the inner agitating blade 27 is formed with a narrow width, the soil can be excavated smoothly and reliably, and the inner end face 27f does not adhere to the excavated soil. The excavation shaft body side guide channel d is formed along the side tapered surface 27h, and the excavated soil is smoothly and reliably guided to the excavation shaft body side.

  As a result, even when the excavated soil is strong clay, the excavated soil and the solidified material can be efficiently and uniformly kneaded while preventing the excavated soil from becoming a lump.

  Next, a ground improvement method for performing ground improvement work by the ground improvement device A described above will be described with reference to FIGS. 4 and 5.

  (1) As shown in FIG. 4 (a), the soil excavated by the excavating blade 10 is solidified and discharged from the first and second solidifying material discharge portions 29 and 32 while being agitated by the relative stirring blade body 9. Kneading with material (ground improvement process).

  At this time, the soil carrying-in / out wing body 40 is disposed above the excavation shaft body 7 by the lifting means and disposed above the surface of the ground G.

  Here, a part of the soil excavated in proportion to the amount of the solidified material discharged may be carried out from the excavation hole H to the ground, but the soil may not be carried out smoothly.

  (2) Then, as shown in FIG. 4 (b), as the contents (soil and solidified material) in the excavation hole H increase, the peripheral surface of the excavation hole H is displaced outward (sideward). When the displacement is detected, the displacement amount is detected by the underground displacement amount detection means 47 disposed in the vicinity of the excavation hole H. The underground displacement amount detection means 47 detects the predetermined allowable displacement amount. When the above displacement is detected, as shown in FIG. 4 (c), the excavation shaft body 7 is moved upward by a required width (for example, a width corresponding to approximately half of the vertical width of the soil loading / unloading wing body 40). In the same state, the soil carrying-in / out wing 40 disposed at the upper part of the excavation shaft 7 is lowered to the vicinity of the surface of the ground G by the lifting means.

  (3) As shown in FIGS. 4 (c) and 4 (d), the excavation shaft body 7 is dug while being rotated forward, and the soil carry-in / out wing body 40 is dug while being rotated forward by the drive / support 61.

  Then, a part of the excavated soil is forcibly carried out to the ground by the earth discharging blade piece 42 of the soil carrying-in / out wing body 40 (soil carrying-out process).

  Accordingly, when the solidified material is supplied (discharged) into the excavation hole H and the contents (soil and solidification material) in the excavation hole H increase, the displacement (side) of the peripheral surface of the excavation hole H increases. Direction displacement) can be suppressed within an allowable range.

  As a result, it is possible to reliably prevent the occurrence of problems such as adversely affecting existing underground structures provided around the soil-improved ground and the ground surface rising.

  (4) As shown in FIG. 4 (e), excavation and agitation work is performed to a predetermined depth, and then the excavation shaft body 7 is pulled up while being inverted.

  At this time, the solidified material is discharged from the first and second solidified material discharge portions 29 and 32, and the excavated soil and the solidified material are kneaded by the relative stirring blade body 9.

  (5) The kneaded soil and the solidified material are solidified.

  Further, when the underground displacement detected by the underground displacement detection means 47 becomes less than a predetermined allowable displacement, the soil carry-in / out wing body 40 is held in the rotation stopped state by the drive / support 61 ( Non-soil removal process).

  And ground improvement work (ground improvement process) can also be restarted while excavating the excavation shaft 7 in such a state.

  At this time, since the soil carry-in / out wing body 40 is in a rotation stopped state by the drive / support 61, the excavated soil is not carried out, and the peripheral surface of the excavation hole H is surrounded by the excess soil carry-out. It is possible to reliably prevent the occurrence of a problem of collapse due to earth pressure.

(Other ground improvement methods)
Next, another ground improvement method using the above ground improvement device A will be described with reference to FIG.

  (1) Before starting the ground improvement work, for example, it is investigated whether there is unnecessary soil that significantly reduces the solidification effect of the solidified material, such as the humus soil layer B shown in FIG.

  (2) The length of the soil carry-in / out wing body 40 is set to a length that reaches the depth of the humus soil layer B.

  (3) As shown in FIG. 5 (a), the ground G is excavated by the excavating blade body 10 provided at the lower end portion of the excavating shaft body 7 extending in the vertical direction, and the excavated soil D is removed from the excavated shaft body 7 Is stirred by a relative stirring blade body 9 provided on the outer peripheral surface (excavation / stirring step).

  At this time, the soil carrying-in / out wing body 40 is driven to rotate forward by the driving / supporting body 61 and carries out part of the soil D excavated by the excavating blade body 10 to the ground (unnecessary soil carrying-out process).

  Then, if necessary, water can be discharged from the first solidification material discharge part 29 and the second solidification material discharge part 32, and excavation / stirring efficiency can be ensured satisfactorily.

  (4) As shown in FIGS. 5 (b) and 5 (c), the excavation / mixing operation and the soil removal operation are continued until the lower end of the lower soil loading / unloading wing body 40 reaches the humus soil layer B (unnecessary soil Unloading process 40) When the humus soil in the excavation hole H is transported to the ground and the soil D, which is deeper than the humus soil layer B, is transported to the ground, the forward rotation drive of the soil transporting entry / exit body 40 is performed. To stop.

  At this time, the excavation / stirring operation is continued, the solidified material is discharged from the first and second solidified material discharge portions 29 and 32, and the excavated soil and the solidified material are kneaded by the relative stirring blade body 9.

  In the excavation / stirring step, the soil carry-in / out wing body 40 is in a rotation stopped state, so that part of the excavated soil D is not carried out to the ground (soil non-carrying step).

  (5) As shown in FIGS. 5 (d) and 5 (e), excavation and agitation work is performed to a predetermined depth, and then the excavation shaft body 7 is pulled up while being inverted.

  At this time, the solidified material is discharged from the first and second solidified material discharge portions 29 and 32, and the excavated soil and the solidified material are kneaded by the relative stirring blade body 9.

  (6) The kneaded soil and the solidified material are solidified.

  Thus, in the excavation / stirring process, for example, when there is unnecessary soil that significantly reduces the solidification effect of the solidified material, such as the humus soil layer B, the unnecessary soil is previously removed in the unnecessary soil carrying-out process. By carrying out to the ground, the effect of kneading and solidifying the solidified material and the excavated soil in a subsequent step can be ensured satisfactorily.

  And, since the work of kneading and solidifying the solidified material and the excavated soil is performed in the soil non-carrying process, it should be avoided that the solidified material kneaded with the soil is carried out to the ground. As a result, the ground improvement work can be performed effectively and efficiently.

  In addition, in the above-mentioned two forms of ground improvement method, when a void or a cavity is generated in the soil D in the excavation hole H due to the removal of the soil, or when there is a possibility that it will occur, the soil carry-in / out wing body is appropriately used. By moving 40 downward, at least a part of the soil carry-in / out wing body 40 is disposed in the excavation hole H, and the soil carry-in / out wing body 40 is reversely rotated at a required rotational speed in the same state. Thus, the soil D carried out to the ground can be carried into the excavation hole H so that voids and cavities are not generated in the soil D in the excavation hole H.

  FIG. 6 shows a relative stirring blade body 9 as a second embodiment, and the relative stirring blade body 9 has the same basic structure as the relative stirring blade body 9 as the first embodiment described above. However, the horizontal component force generating portions 36, 37 are provided in the middle of the inner and outer stirring blades 27, 28, and the horizontal component force generating portions 36, 37 are used for the stirring force of the inner and outer stirring blade bodies 27, 28. The difference is that a horizontal component force is generated outwardly from the excavated soil.

  That is, as shown in FIG. 7, the inner stirring blade 27 and the outer stirring blade 28 are formed in an arc-like similar shape extending in the vertical direction, and the vertical blade pieces 27c and 28c extending in the vertical direction in the middle part. Thus, the vertical blade pieces 27c, 28c have a fixed angle θ1, θ2 (for example, θ1, θ2 = 5 ° to 45) between the outer surfaces 27d, 28d and the tangents S1, S2 of the rotation trajectories K1, K2. (Degrees, preferably 20 degrees), the horizontal component force generating portions 36 and 37 are inclined.

  In the present embodiment, when the excavation blade body 10 is dug while rotating in the direction a which is normal rotation (clockwise rotation in the plan view of FIG. 4), as shown in FIG. It can be generated as horizontal component forces F1h and F2h that push outward acting forces F1 and F2 from the vertical blade pieces 27c and 28c to the excavated soil.

  Therefore, by the inner and outer relative stirring of the inner stirring blade 27 and the outer stirring blade 28, the two-dimensional stirring and kneading of the excavated soil located inside the outer stirring blade 28 can be performed. The vertical blade pieces 27c and 28c of the inner and outer agitating blades 27 and 28 allow the agitating and kneading force to act in the outer direction, forcing the excavated soil against the peripheral surface of the excavation hole. And can be consolidated.

  FIG. 8 is a cross-sectional plan view of the outer agitating blade 28 as an example of transformation, in which the cross-sectional width of the vertical blade piece 28c is formed such that the end surface 28g on the counter-rotation direction side is thicker than the end surface 28f on the rotation direction side. The outer surface 28d is a tapered surface, and the vertical blade piece 28c has a constant angle θ2 (for example, θ2 = 5 ° to 45 °, preferably between the outer surface 28d and the tangent S2 of the rotation locus K2, preferably 20 °) is formed as a horizontal component force generating portion 37 that is inclined so as to be formed.

  In the present embodiment, when the excavating blade body 10 is dug while rotating in the direction a which is normal rotation (clockwise rotation in the plan view of FIG. 4), as shown in FIG. It can be generated as a horizontal component force F2h that pushes the acting force F2 from the vertical blade piece 28c to the excavated soil outward.

  Therefore, since the vertical blade piece 28c of the outer stirring blade 28 can apply the stirring and kneading force also in the outer direction, the excavated soil can be forcedly pressed against the peripheral surface of the drilling hole to be consolidated. it can.

  FIG. 9 shows a relative stirring blade body 9 as the third embodiment, and the relative stirring blade body 9 has the same basic structure as the relative stirring blade body 9 as the second embodiment described above. However, without providing the excavating blade body 10, the excavation bits 14 are provided at the lower end edge of the lower horizontal blade piece 28b of the outer agitating blade 28 and the lower end portion of the outer shaft 21, respectively. To be able to drill.

  In this way, the structure of the ground improvement device A can be simplified.

  In the present embodiment, the solidification material is supplied from the solidification material supply unit 2 to the excavation shaft body 7 and the solidification material is discharged from the first and second solidification material discharge units 29 and 32. A ground improvement agent may be discharged instead of the solidifying material. Here, the ground improvement agent refers to one that purifies or neutralizes soil contaminated with harmful substances to make it pollution-free.

Side explanatory drawing of the ground improvement apparatus which concerns on this invention as 1st Embodiment. The partially cutaway side view of a drilling shaft body and a relative stirring blade body. FIG. Process explanatory drawing of ground improvement work. Process explanatory drawing of the other ground improvement work by the ground improvement apparatus. Side surface explanatory drawing of the ground improvement apparatus which concerns on this invention as 2nd Embodiment. FIG. Cross-sectional plane explanatory drawing of the outer side stirring blade as a modification example. Side surface explanatory drawing of the ground improvement apparatus which concerns on this invention as 3rd Embodiment.

Explanation of symbols

A Ground improvement device G Ground 1 Base machine 2 Solidification material supply part 3 Base machine body 4 Leader

Claims (4)

A drilling blade is provided at the lower end of the drilling shaft extending in the vertical direction, a stirring blade is provided on the outer peripheral surface of the drilling shaft located above the drilling blade, and the ground is excavated by the drilling blade. , While agitating the excavated soil with the agitating blade body, discharging the solidification material or ground improvement agent from the discharge portion provided at a predetermined location, and kneading the solidification material or ground improvement agent and the excavated soil In the ground improvement device designed to improve the ground by
The soil carry-in / out wing body is provided on the outer peripheral surface of the excavation shaft body. The forward and reverse rotation drive or rotation stop state can be maintained around the axis of the excavation shaft body, and it can be moved up and down along the excavation shaft body .
The soil carrying-in / out wing body can be arranged above the surface of the ground independently of the excavating shaft body that digs into the ground, and can also be dug into the ground. Ground improvement device. A drilling blade is provided at the lower end of the drilling shaft extending in the vertical direction, a stirring blade is provided on the outer peripheral surface of the drilling shaft located above the drilling blade, and the ground is excavated by the drilling blade. , While agitating the excavated soil with the agitating blade body, discharging the solidification material or ground improvement agent from the discharge portion provided at a predetermined location, and kneading the solidification material or ground improvement agent and the excavated soil In the ground improvement device designed to improve the ground by
A soil carry-in / out wing body is provided on the outer peripheral surface of the excavation shaft body, and the soil carry-in / out wing body can be rotated forward / reversely around the axis of the excavation shaft body independently of the excavation shaft body, and Can move up and down along the drilling shaft
The stirring blade body is formed by extending in the vertical direction, and the upper and lower ends are attached to the excavation shaft body, and the middle portion is formed to bulge outward, and the excavation shaft body is centered in the middle portion. A horizontal component force generating part in the radial direction is provided, and the horizontal component force generating part generates a horizontal component force in the radial direction from the stirring force of the stirring blade body to the excavated soil. and the ground board improved apparatus you. A ground improvement method for performing ground improvement work by the ground improvement device according to claim 1,
The soil carry-in / out wing body is disposed above the excavation shaft body by the lifting means, thereby disposing the soil excavated by the excavation blade body with the relative stirring blade. Kneading with the solidified material discharged from the discharge unit while stirring by the body;
As the soil and solidification material in the excavation hole increase, the peripheral surface of the excavation hole is displaced outward, and the underground displacement detection means disposed in the vicinity of the excavation hole exceeds the predetermined allowable displacement. When the displacement amount is detected, the excavation shaft body is lifted upward by the required width, and in this state, the soil carry-in / out wing body arranged at the upper part of the excavation shaft body is moved by the lifting means in the vicinity of the ground surface. Step of lowering to
While excavating the excavating shaft body while rotating forward, and excavating the soil carrying-in / out wing body while rotating forward by the drive / support, a part of the excavated soil is forced by the soil carrying-in / out wing body. A step of suppressing the displacement of the peripheral surface of the excavation hole to the outside within an allowable range due to the increase in soil and solidified material in the excavation hole,
Performing excavation and agitation work to a predetermined depth, and then pulling up the excavation shaft body while reversing and kneading the excavated soil and solidified material with a relative agitation blade body;
A step of solidifying the kneaded soil and the solidifying material;
The ground improvement construction method characterized by having. A ground improvement method for performing ground improvement work by the ground improvement device according to claim 1,
Before starting the ground improvement work, the step of setting the length of the soil carry-in / out wing body to a length that reaches the depth at which unnecessary soil that significantly reduces the solidification effect of the solidification material exists,
The ground is excavated by the excavating blade provided at the lower end of the excavating shaft extending in the vertical direction, and the excavated soil is agitated by a relative agitating blade provided on the outer peripheral surface of the excavating shaft. The carry-in / out wing body is driven to rotate forward by the drive / support body, and a part of the soil excavated by the excavating blade body is carried out to the ground;
Continue excavation / stirring work and soil removal work until the lower end of the soil carry-in / out wing body reaches the unnecessary soil, carry the unnecessary soil in the excavation hole to the ground, and more than the unnecessary soil The process of stopping the forward rotation drive of the soil carry-in / out wing body, after confirming that the soil in the deep layer is carried out to the ground,
While the soil carry-in / out wing body is in a rotation stopped state, the solidification material is discharged from the discharge part, and the excavated soil and the solidification material are kneaded by the relative stirring wing body,
Performing excavation and agitation work to a predetermined depth, and then pulling up the excavation shaft body while reversing and kneading the excavated soil and solidified material with a relative agitation blade body;
A step of solidifying the kneaded soil and the solidifying material;
The ground improvement construction method characterized by having.

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