JP2021011679A - Agitation device and ground improvement method of pile burying hole - Google Patents

Abstract

To reduce construction cost by improving ground after removing buried piles to the same strength and rigidity as those of surrounding ground.SOLUTION: When a braking blades 78 are positioned in highly viscous sediment 42, the sediment 42 is agitated with multiple second rotary blades 62 of high rotation speed and multiple first rotary blades 76 of low rotation speed. When the braking blades 78 are positioned in low viscous slurry 44, even in a case where the rotation speeds of the first rotary blades 76 and the second rotary blades 62 coincide with each other, the sediment 42 is agitated by vertically moving an agitation device 46. The rotation of a hydraulic motor 1604 rotating the agitation device 46 is controlled such that the hydraulic pressure is kept at the vicinity of an upper limit and not exceeding the upper limit of an allowed range set to the hydraulic motor 1604, on the basis of a map prepared in advance corresponding to each of multiple kinds of sediment 42 having different properties and showing a relationship between a rotation speed N of the hydraulic motor 1604 and the hydraulic pressure of hydraulic oil supplied to the hydraulic motor 1604.SELECTED DRAWING: Figure 2

Description

The present invention relates to a stirring device used for backfilling work of a pile buried hole remaining after removal of a buried pile and a method for improving the ground of the pile buried hole.

When rebuilding a building or structure, after removing the building or structure, it is necessary to pull out the existing buried pile buried in the ground and backfill the pile burial hole that remains after the pulling out.
Conventionally, a drilling rig 10 as shown in FIG. 12 has been used for removing buried piles.
The drilling rig 10 includes a crane 12, a leader 14, a rotary drive unit 16, a casing 18, and a water supply device 20.
The crane 12 includes a lower traveling body 1202, an upper swivel body 1204 provided on the upper part of the lower traveling body 1202 so as to be swivel, and a boom 1206 provided on the upper swivel body 1204 so as to be undulating and expandable in the vertical direction. It has.
A wire 1212 is suspended from a mounting member 1208 at the tip of the boom 1206 via a pulley 1210, and the wire 1212 is guided by the upper swing body 1204 along the boom 1206 to a hoisting device (not shown) of the upper swing body 1204. The wire 1212 is wound and unwound.
The leader 14 is swayably suspended from the mounting member 1208 at the tip of the boom 1206, and the lower end of the leader 14 is installed on the ground G.

The rotation drive unit 16 includes a case 1602, a hydraulic motor 1604 housed in the case 1602, and a rotation shaft 1606 rotationally driven by the hydraulic motor 1604.
The case 1602 has a guided portion 1608 guided by the reader 14, and is connected to the tip of the wire 1212 with the rotating shaft 1606 directed vertically downward, and is moved up and down along the leader 14 by winding and unwinding the wire 1212. Moved in the direction.
The casing 18 is configured such that the upper end and the lower end of each cylindrical casing division 26 in the axial direction are connected via bolts. In this example, the casing 18 is connected to four casing divisions 26. It is composed of.
The inner diameter of each casing split body 26 is formed to be larger than the outer diameter of the buried pile 22.
The uppermost casing divided body 26 is an upper end casing divided body 28 having a connecting portion 2802 whose upper portion is integrally rotatably and detachably connected to the rotating shaft 1606.
The casing dividing body 26 located at the lowermost position is the excavation casing dividing body 34, and the excavation casing dividing body 34 has a cutter for excavation (not shown) taken at a place spaced along the lower end of the outer peripheral surface thereof. It is worn.
The casing divisions 26 that connect the upper end casing division 28 and the excavation casing division 34 are the intermediate casing divisions 30 and 32.
Further, a water supply pipe (not shown) is provided from the rotation shaft 1606 of the rotary drive unit 16 to the entire length of the casing 18, and a water injection hole (not shown) for injecting water from the water supply pipe is provided at the lower end of the excavation casing 18. It is formed.
The water supply device 20 supplies water to the water supply pipe, and the water supply device 20 and the water supply pipe are a pipeline (not shown) provided in the rotary drive unit 16 and a water supply hose connected to the pipeline. It is connected by 21.

The procedure for removing the buried pile 22 using the drilling device 10 is as follows.
As shown in FIG. 12, the ground G is excavated in advance so that the upper part of the buried pile 22 is exposed.
Next, the support frame 24 is installed around the buried pile 22, and the drilling device 10 is moved and installed in the vicinity of the buried pile 22.
The upper swing body 1204 of the crane 12 is swiveled and the boom 1206 is extended so that the casing 18 is located above the buried pile 22 and the axis of the casing 18 is aligned with the axis of the buried pile 22. ..
At this time, the lower end of the reader 14 is installed above the support frame 24 so that the leader 14 is maintained in a vertically extending state.

Next, the ground G around the buried pile 22 is excavated by the casing 18 by feeding out the wire 1212 of the crane 12 while rotating the casing 18 by the rotation driving unit 16. At this time, water is supplied from the water supply device 20 toward the water supply pipe, so that water is injected from the water injection hole at the tip of the excavation casing split body 34.
As a result, as shown in FIG. 13 (A), the ground G is dissolved by the water jetted from the water injection hole to form a muddy water, and the excavation casing divided body 34 becomes the ground G due to the own weight and rotational force of the casing 18. It enters and excavates the ground G on the outer side in the radial direction of the buried pile 22 in a cylindrical shape.
Eventually, as shown in FIG. 13B, when the tip of the excavation casing split body 34 reaches substantially the same position as the lower end of the buried pile 22, the casing 18 is rotated by winding the wire 1212 of the crane 12. While pulling out from the ground G.
As a result, as shown in FIG. 13C, the outer peripheral surface of the buried pile 22 and the ground G are cut off over the entire length of the buried pile 22, and the outer peripheral surface of the buried pile 22 and the inner peripheral surface of the excavation hole 36 are cut off. The muddy water 38, which is a mixture of the jetted water and the excavated earth and sand, remains between the two.
Next, a wire (not shown) is wound around the buried pile 22, and one end of the wire on the above-ground side is pulled up by another heavy machine, so that the buried pile 22 is pulled out from the ground G and removed.
As shown in FIG. 13 (D), a pile burial hole 40 is formed in the ground G from which the burial pile 22 is pulled out from the excavation hole 36, and muddy water 38 is accumulated in the pile burial hole 40.
Since the muddy water 38 is settled with the passage of time, sediment 42 having a heavy specific gravity and high viscosity is deposited in the lower part of the pile burial hole 40, while fine-grained soil is suspended in the upper part of the pile burial hole 40. Low muddy water 44 will accumulate.

Here, muddy water solidification is carried out by injecting a solidifying material which is a self-hardening solution into the pile burial hole 40 and stirring by air blow to improve the ground of the pile burial hole 40 in the same manner as the surrounding ground G. Is performed.
Alternatively, a solidifying material such as cement milk is injected into the pile burial hole 40 with a screw auger and stirred to solidify the muddy water, and the ground of the pile burial hole 40 is improved in the same manner as the surrounding ground G.

Japanese Unexamined Patent Publication No. 2015-183501

However, in the above-mentioned conventional technique, when stirring by air blow is used, if the sediment 42 deposited in the pile burial hole 40 has a high viscosity, it is difficult to sufficiently stir the entire sediment 42 and the solidifying material, and the pile is buried. There is room for improvement in spreading the solidifying material throughout the sediment 42 deposited in the hole 40, and there is a disadvantage in improving the ground after the removal of the buried pile 22 to the same strength and rigidity as the surrounding ground G. is there.
Further, when a screw auger is used, it is necessary to prepare a screw auger which is a heavy machine different from the drilling device 10, which has a disadvantage that the construction cost increases.
The present invention has been devised in view of the above circumstances, and an object of the present invention is to spread the solidifying material over the entire sedimentary sediment deposited in the pile burial hole to surround the ground after the removal of the buried pile. It is an object of the present invention to provide a stirrer and a method for improving the ground of a pile burial hole, which is advantageous in improving the strength and rigidity equivalent to that of the ground and also in reducing the construction cost.

In order to achieve the above object, the present invention is used in place of an excavation casing split at the lower end of the casing of an excavator suspended by a crane and rotationally driven by a hydraulic motor, and deposits and sediment deposited in a pile burial hole. A stirring device that agitates muddy water and a solidifying material, the stirring device is arranged with its axis oriented in the vertical direction, and is removable from the portion of the casing directly above the excavation casing divided body, and has a lower end outer peripheral portion. A tubular stirring casing dividing body having a cutter for excavation, stirring blades arranged inside the stirring casing dividing body, and a water supply unit for supplying water to the lower end of the stirring casing divided body. A solidifying material supply unit for supplying the solidifying material and a rotation control unit for controlling the rotation of the hydraulic motor are provided at the lower end of the stirring casing divided body, and the stirring blade extends along the axis. The distance between the rotating shafts that are immovable in the axial direction of the stirring casing split body and are rotatably arranged on the axial center and the longitudinal direction of the rotating shafts from the upper and lower middle portions to the lower part of the rotating shafts. A plurality of first rotating blades extending outward in the radial direction of the rotating shaft from a portion spaced in the circumferential direction at the place where the rotation shaft is placed, and the rotating shaft from a portion spaced in the circumferential direction above the rotating shaft. It has a plurality of braking blades extending outward in the radial direction, and the inner peripheral surface of the stirring casing dividing body is spaced from the upper and lower middle portions to the lower portion in the axial direction. A plurality of second rotary blades extending inward in the radial direction of the stirring casing split body are provided at locations spaced apart from each other in the circumferential direction, with positions shifted in the axial direction with respect to the first rotary blades. A switching unit is provided for switching between a state in which the rotating shaft can be rotated with respect to the stirring casing divided body and a state in which the rotating shaft can be integrally rotated with the stirring casing divided body. The rotation control of the hydraulic motor is a correlation between the rotational speed of the hydraulic motor and the hydraulic pressure of the hydraulic oil supplied to the hydraulic motor, which are created in advance corresponding to each of a plurality of types of sediments having different properties. It is characterized in that the hydraulic pressure is set in the vicinity of the upper limit value of the allowable range defined for the hydraulic motor and does not exceed the upper limit value based on the map showing the relationship or the regression equation.
Further, the present invention includes a tubular stirring casing divided body that is arranged with its axial center oriented in the vertical direction and whose both ends in the axial direction are open, and a stirring blade arranged inside the stirring casing divided body. A stirring device including a solidifying material supply unit for supplying the solidifying material is provided inside the stirring casing divided body, and the stirring blades extend along the axis and the axis of the stirring casing divided body. A rotation shaft that is immovable in the direction and is rotatably arranged on the axis, and a portion that is spaced from the upper and lower middle portions of the rotation shaft to the lower portion in the longitudinal direction of the rotation shaft, are spaced in the circumferential direction. A plurality of first rotary blades extending outward in the radial direction of the rotating shaft from the location where the rotating shaft was located, and a plurality of braking blades extending outward in the radial direction of the rotating shaft from a portion spaced in the circumferential direction above the rotating shaft. At a location spaced in the axial direction from the upper and lower middle portions of the stirring casing split body to a portion spaced in the circumferential direction of the inner peripheral surface of the stirring casing split body. A plurality of second rotary blades extending inward in the radial direction of the stirring casing split body are provided so as to be displaced in the axial direction with respect to the first rotary blade, and further, the rotary shaft is divided into the stirring casing divisions. A switching unit for switching between a state in which the body can rotate and a state in which the rotating shaft can rotate integrally with the stirring casing split body is provided, and a hydraulic motor for rotating the stirring casing split body is provided. When the braking blade is located in highly viscous sediment, the rotating shaft is switched to a rotatable state by a switching portion, and the stirring casing split body is rotated while supplying the solidifying material, so that the braking blade is When it is located in muddy water having low viscosity, the rotating shaft is switched to a state where it can be integrally rotated with the stirring casing split body by the switching portion, and the stirring casing split body is rotated while supplying a solidifying material. The stirring device is moved up and down, and the rotation control of the hydraulic motor is applied to the rotational speed of the hydraulic motor and the hydraulic motor, which are created in advance corresponding to each of a plurality of types of sediments having different properties. Based on a map showing the correlation with the hydraulic pressure of the supplied hydraulic oil or a regression equation, the hydraulic pressure is performed so as to be near the upper limit value of the allowable range defined for the hydraulic motor and not to exceed the upper limit value. And.

According to the present invention, when the braking blade is located in highly viscous sediment, the buried pile is provided by both the plurality of second rotary blades having a high rotation speed and the plurality of first rotary blades having a slow rotation speed. Since the agitation of the sediment accumulated in the pile burial hole from which the above is removed is promoted, the solidifying material supplied from the solidifying material supply section and the sediment are efficiently and uniformly mixed.
Further, even when the braking blades are located in the muddy water having low viscosity and the rotation speeds of the first rotating blade and the second rotating blade match, the buried pile is removed by moving the stirring device up and down. Since the agitation of the accumulated sediment accumulated in the pile burial hole is promoted, the solidified material supplied from the solidifying material supply unit and the accumulated sediment are efficiently and uniformly mixed.
Therefore, it is advantageous to spread the solidifying material over the entire sediment accumulated in the pile burial hole in order to improve the ground after the removal of the buried pile to have the same strength and rigidity as the surrounding ground.
In addition, the agitator can be rotated by the drilling device and used, and the ground can be improved without using other heavy machinery different from the conventional drilling device, and the time required for the ground improvement can be significantly shortened, and the construction cost can be reduced. It is advantageous in reducing the amount of
Further, in the present embodiment, the rotation speed and the hydraulic pressure of the hydraulic motor, which are created in advance corresponding to each of a plurality of types of sediments having different properties, are controlled to rotate the hydraulic motor that rotates the stirring casing divided body. Based on the map showing the correlation with the oil pressure of the hydraulic oil supplied to the motor, the oil pressure is set to be close to the upper limit value of the allowable range set for the hydraulic motor and not to exceed the upper limit value.
Therefore, the rotation speeds of the first rotary blade and the second rotary blade can be maximized according to the properties of the sediment to be agitated without affecting the durability and life of the hydraulic motor. It goes without saying that the sediment can be mixed efficiently and uniformly, and the time required for ground improvement can be significantly shortened, which is more advantageous in reducing the construction cost.

It is explanatory drawing of the drilling rig to which the stirring apparatus of 1st Embodiment was applied. It is a perspective view which a part of the stirring apparatus which concerns on 1st Embodiment is broken. It is a vertical sectional view of the stirring apparatus which concerns on 1st Embodiment. It is a perspective view which omitted the illustration of the stirring blade from FIG. It is a perspective view which omitted the illustration of the casing for stirring division which forms a cylinder from FIG. (A) is an explanatory view showing the retracted position of the connecting member, and (B) is an explanatory view showing the connecting position of the connecting member. It is a block diagram which shows the structure of the rotation control device. (A)-(D) is a diagram of a map showing the correlation between the rotational speed of the hydraulic motor and the oil pressure supplied to the hydraulic motor. It is an operation flowchart of the stirring apparatus which concerns on 1st Embodiment. It is a block diagram which shows the structure of the rotation control device in 2nd Embodiment. It is a block diagram which shows the structure of the rotation control device in 3rd Embodiment. It is explanatory drawing of the drilling rig which has been used conventionally. It is explanatory drawing of the removal method of the buried pile using an excavator, (A) shows the state which the excavation of the ground by an excavation casing is started, and (B) shows the state which excavation of the ground by an excavation casing is finished. , (C) shows the state where the casing is pulled out from the ground and muddy water remains between the outer peripheral surface of the buried pile and the ground, and (D) shows the accumulated sediment and muddy water accumulated in the pile burial hole from which the buried pile was removed. Indicates the state.

(First Embodiment)
The first embodiment of the present invention will be described below with reference to FIGS. 1 to 9.
In the following embodiments, the same parts and members as those in FIG. 10 are designated by the same reference numerals, and the description thereof will be omitted.
FIG. 1 is an explanatory view of an excavation device 10 to which the stirring device of the present embodiment is applied.
In the excavation device 10, the lowermost excavation casing division 34 of the casing 18 is replaced with the stirring casing division 34A constituting the stirring device 46 of the present invention, and the remaining upper end casing division 28 and The plurality of intermediate casing divided bodies 30 and 32 are provided by a water supply pipe 48 that supplies water to the stirring device 46, a hydraulic oil supply pipe 50 that supplies hydraulic oil, and a solidifying material supply pipe 52 that supplies solidifying material. It is replaced with the worn upper casing divider 28A and the plurality of intermediate casing dividers 30A, 32A.
The outer dimensions of the upper end casing divided body 28A, the plurality of intermediate casing divided bodies 30A and 32A, the stirring casing divided body 34A, and the structure for connecting the divided bodies 28A, 30A, 32A, and 34A in a detachable manner have been conventionally used. This is the same as the upper end casing divided body 28, the plurality of intermediate casing divided bodies 30, 32, and the excavated casing divided body 34 used in the excavation device 10.
Further, each of the divided bodies 28A, 30A, 32A and 34A is made of steel.

Then, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 are connected over the upper end casing division 28, the plurality of intermediate casing divisions 30A and 32A, and the stirring casing division 34A, and the upper end casing division body is formed. 28A, a plurality of intermediate casing divided bodies 30A and 32A, and a stirring casing divided body 34A are connected to form a casing 18A.

Similar to FIG. 10, the rotary drive unit 16A is configured to include the hydraulic motor 1604 and rotationally drives the casing 18A, and the coupling between the rotary drive unit 16A and the upper end casing split body 28 is, for example, rotary drive. By connecting the hexagonal cylinder portion of the rotating shaft 1606 at the lower end of the portion 16A and the hexagonal cylinder portion of the connecting portion 2802 at the upper end of the upper end casing dividing body 28, or by the outer peripheral cylinder of the rotating shaft 1606 at the lower end of the rotation driving unit 16A. Various conventionally known connecting and connecting structures can be adopted, such as covering the portion with the small-diameter tubular portion at the upper end of the upper end casing split body 28 and connecting the portions with bolts and nuts.
The rotation drive unit 16A is connected to the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 of the upper end casing division 28A, the plurality of intermediate casing divisions 30A and 32A, and the stirring casing division 34A from the rotation shaft 1606. On the other hand, all of the water, hydraulic oil, and solidifying material to be supplied are replaced with a rotary drive unit 16A having a water pipe, a hydraulic oil pipe, and a solidifying material pipe (not shown).

Further, the hydraulic oil is supplied to the water pipe, the hydraulic oil pipe, and the solidifying material pipe of the rotary drive unit 16A via the water supply device 20 that supplies water via the water supply hose 21 and the hydraulic oil through the hydraulic oil hose 55. The hydraulic oil supply device 54 is connected to the solidifying material supply device 56 that supplies the liquid solidifying material via the solidifying material hose 57.
As the solidifying material, various conventionally known materials such as cement milk that are mixed with the sediment 42 and solidified can be used.

The water supply device 20 is configured to supply and stop the supply of water by manual operation, and the hydraulic oil supply device 54 supplies and supplies hydraulic oil by the switching control unit 96 (see FIG. 7) of the rotation control device 58. The solidifying material supply device 56 is configured to supply and stop the supply of the solidifying material by manual operation.
The rotation control device 58 controls the rotation of the casing 18A by the rotation drive unit 16A, and the rotation control device 58 controls the rotation of the hydraulic motor 1604 on / off, the rotation speed (the number of rotations per unit time), and the rotation direction. It controls the switching between forward and reverse.

As shown in FIGS. 2 to 4, the stirring device 46 includes a stirring casing dividing body 34A forming a tubular body, a stirring blade 60, a second rotary blade 62, a bearing 64, and a switching portion 66. It is configured.
The stirring casing divided body 34A has a cylindrical shape with both ends open in the axial direction, and is arranged so that the axial center is directed in the vertical direction.
The upper end of the stirring casing dividing body 34A is detachably connected to the portion of the casing 18A directly above the stirring casing dividing body 34A, that is, the lower end of the intermediate casing dividing body 32A located at the lowermost position via a bolt. ing. This connecting structure is the same as the connecting structure of the conventional intermediate casing split body 32 and the excavation casing split body 34.
Further, a cutter 68 for excavation is provided on the outer peripheral portion of the lower end of the stirring casing divided body 34A.

Further, the stirring casing divided body 34A includes a water supply pipe 48, a hydraulic oil supply pipe 50, a solidifying material supply pipe 52, a water injection hole 70 (see FIG. 1), and a solidifying material injection hole 72. There is.
As shown in FIGS. 2 and 3, the water supply pipe 48 is provided on the outer peripheral surface of the stirring casing dividing body 34A from the upper end of the stirring casing dividing body 34A along the axial direction of the stirring casing dividing body 34A. It extends to the position of the excavation cutter 68 at the lower end of the divided body 34A.
The upper end of the water supply pipe 48 is connected to the lower end of the water supply pipe 48 of the intermediate casing division 32A to which the stirring device 46 (stirring casing division 34A) is connected, and the water injection hole 70 is connected to the lower end of the water supply pipe 48. Is provided.
Therefore, the water supplied from the water supply device 20 is injected from the water injection hole 70 below the stirring casing division 34A via the water supply hose 21, the water pipeline of the rotary drive unit 16A, and the water supply pipe 48. ..
In the present embodiment, the water supply device 20, the water supply hose 21, the water pipe of the rotary drive unit 16A, and the water supply pipe 48 of the casing 18A constitute the water supply unit within the scope of the claims.

As shown in FIGS. 2 and 3, the hydraulic oil supply pipe 50 is used for stirring from the upper end of the stirring casing dividing body 34A along the axial direction of the stirring casing dividing body 34A on the outer peripheral surface of the stirring casing dividing body 34A. It extends to the middle portion of the casing split 34A.
The upper end of the hydraulic oil supply pipe 50 is connected to the lower end of the hydraulic oil supply pipe 50 of the intermediate casing division 32A to which the stirring device 46 (stirring casing division 34A) is connected, and is provided in the stirring casing division 34A. The lower end of the hydraulic oil supply pipe 50 is connected to a switching portion 66 described later.
Therefore, the hydraulic oil supplied from the hydraulic oil supply device 54 is supplied to the switching unit 66 via the hydraulic oil hose 55, the hydraulic oil pipeline of the rotary drive unit 16A, and the hydraulic oil supply pipe 50.

As shown in FIGS. 2 and 3, the solidifying material supply pipe 52 is used for stirring from the upper end of the stirring casing dividing body 34A along the axial direction of the stirring casing dividing body 34A on the outer peripheral surface of the stirring casing dividing body 34A. It extends to the location of the excavation cutter 68 at the lower end of the casing split 34A.
The upper end of the solidifying material supply pipe 52 is connected to the lower end of the solidifying material supply pipe 52 of the intermediate casing divided body 32A to which the stirring device 46 (stirring casing dividing body 34A) is connected, and is solidified at the lower end of the solidifying material supply pipe 52. A material injection hole 72 is provided.
Therefore, the solidifying material supplied from the solidifying material supply device 56 is a casing divided body for stirring from the solidifying material injection hole 72 via the solidifying material hose 57, the solidifying material conduit of the rotary drive unit 16A, and the solidifying material supply pipe 52. It is injected below 34A.
In the present embodiment, the solidifying material supply device 56, the solidifying material hose 57, the solidifying material pipeline of the rotary drive unit 16A, and the solidifying material supply pipe 52 of the casing 18A constitute the solidifying material supply unit within the scope of the claims. ing.

In addition, in order to connect to the water pipe, the hydraulic oil pipe, and the solidifying material pipe of the rotary drive unit 16A, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 are divided into the upper casing in the upper end casing split body 28A. It is provided inside the body 28A.
Further, in order to connect to the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 of the stirring casing dividing body 34A, water is at least in the intermediate casing dividing body 32A located directly above the stirring casing dividing body 34A. The lower parts of the supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 extend outward in the radial direction of the stirring casing dividing body 34A, penetrate the intermediate casing dividing body 32A, and pass through the intermediate casing dividing body 32A, and the outer periphery of the intermediate casing dividing body 32A. It is placed on the surface.

As shown in FIGS. 2 to 5, the stirring blade 60 is arranged at the axial center of the stirring casing divided body 34A.
The stirring blade 60 has a rotating shaft 74, a plurality of first rotating blades 76, and a plurality of braking blades 78.
The rotating shaft 74 is made of steel and is rotatably arranged on the axis of the stirring casing dividing body 34A.
The plurality of first rotary vanes 76 are located at locations spaced in the longitudinal direction of the rotary shaft 74 from the upper and lower middle portions of the rotary shaft 74 to the lower portion in the radial direction from the locations spaced in the circumferential direction. Extends to.
In the present embodiment, the first rotary vanes 76 are provided at two locations spaced apart from each other in the longitudinal direction of the rotating shaft 74 and at two locations spaced apart from each other by 180 ° in the circumferential direction. Are provided in total of four.
Further, a cylindrical connecting ring 80 for connecting the radial outer ends of the first rotating blades 76 is provided for each of the plurality of first rotating blades 76 extending from the same position in the longitudinal direction of the rotating shaft 74. ..
The vertical width of the connecting ring 80 is larger than the width of the first rotary vane 76, and the vertical end of the connecting ring 80 protrudes upward and downward from the vertical end of the first rotary vane 76, respectively. ing.
The plurality of braking blades 78 extend outward in the radial direction of the rotating shaft 74 from locations spaced apart from each other in the circumferential direction above the rotating shaft 74.
In the present embodiment, the braking blades 78 are provided at four locations at intervals of 90 ° in the circumferential direction of the upper end of the rotating shaft 74, and therefore, a total of four braking blades 78 are provided.

The plurality of second rotary blades 62 are spaced in the circumferential direction of the inner peripheral surface of the stirring casing dividing body 34A at locations that are spaced from the upper and lower middle portions of the stirring casing dividing body 34A in the axial direction. The agitating casing divided body 34A extends inward in the radial direction, and the plurality of second rotary blades 62 are provided so as to be displaced in the axial direction (phase) with respect to the first rotary blade 76. ..
In the present embodiment, the plurality of second rotary blades 62 are provided at three locations spaced apart from each other in the axial direction by 180 ° in the circumferential direction of the inner peripheral surface of the stirring casing dividing body 34A. It is provided, and a total of 6 second rotating blades 62 are provided.
The first rotary vane 76, the braking vane 78, and the second rotary vane 62 are each formed of a steel flat plate having a constant width and an integral length, and the width direction is directed toward the axial direction and the length direction is used for stirring. The casing split body 34A is arranged in the radial direction so that the sediment 42 and the solidifying material can be efficiently mixed.
Further, the number of the first rotary vane 76, the braking vane 78, and the second rotary vane 62 is not limited to the embodiment and can be set as appropriate.

The bearing 64 rotatably supports the rotating shaft 74 and immovably supports the rotating shaft 74 in the axial direction on the inner peripheral surface of the stirring casing divided body 34A.
In the present embodiment, the bearing 64 can rotate the rotary shaft 74 and support the rotary shaft 74 so as to be rotatable and immovably supportable in the axial direction of the rotary shaft 74 by supporting the vertical end portion of the connecting ring 80 in the vertical direction. It is immovably supported in the axial direction.
As shown in FIG. 3, in the bearing 64, a pair of lower locking pieces 82 and upper locking pieces 84 provided at a plurality of locations vertically spaced apart from each other on the inner peripheral surface of the stirring casing dividing body 34A It is configured to be provided at a plurality of locations spaced apart in the direction.
The lower locking piece 82 includes a lower base portion 8202 protruding inward in the radial direction from the inner peripheral surface of the stirring casing split body 34A, and a lower standing portion 8204 standing upward from the tip of the lower base portion 8202.
The upper locking piece 84 includes an upper base portion 8402 protruding inward in the radial direction from the inner peripheral surface of the stirring casing divided body 34A, and an upper standing portion 8404 standing downward from the tip of the upper base portion 8402.
The lower base portion 8202 and the upper base portion 8402 are movably contacted with the lower end portion and the upper end portion of the connecting ring 80, and the lower standing portion 8204 and the upper standing portion 8404 are formed on both sides of the connecting ring 80 in the thickness direction. The inner peripheral surface of the stirring casing dividing body 34A is movably contacted, and the connecting ring 80 is supported so as not to be movable in the axial direction of the stirring casing dividing body 34A and movable in the circumferential direction.

As shown in FIGS. 6A and 6B, the switching unit 66 has a state in which the rotating shaft 74 can be rotated with respect to the stirring casing dividing body 34A on the inner peripheral surface of the stirring casing dividing body 34A. The rotating shaft 74 is switched to a state in which it can rotate integrally with the stirring casing divided body 34A.
The switching unit 66 includes an actuator 86 and a contact member 88.
The actuator 86 is attached to the inner peripheral surface of the stirring casing divided body 34A.
The contact member 88 has a retracted position separated from the first rotary vane 76 in the axial direction of the stirring casing divided body 34A by the actuator 86 as shown in FIG. 6 (A), and as shown in FIG. 6 (B). It abuts on the first rotary vane 76 in the circumferential direction of the axis and moves between the contact position where the first rotary vane 76 is rotated integrally with the stirring casing dividing body 34A.
In the present embodiment, the actuator 86 is a hydraulic cylinder, the hydraulic cylinder includes a piston rod that expands and contracts with the hydraulic oil supplied from the hydraulic oil supply pipe 50, and the contact member 88 is composed of the piston rod. ..
The piston rod is urged in a direction of being constantly immersed by a spring built in the hydraulic cylinder, and the piston rod protrudes against the urging force by supplying hydraulic oil.
Therefore, when the hydraulic oil is not supplied, the contact member 88 is positioned at the retracted position due to the immersion of the piston rod, and when the hydraulic oil is supplied, the contact member 88 is positioned at the contact position due to the protrusion of the piston rod. To position.
As the actuator, various conventionally known actuators such as an electric cylinder can be used.

Next, the rotation control device 58 will be described in detail.
As shown in FIG. 7, the rotation control device 58 includes a tank 5802, a hydraulic pump 5804, a direction switching valve 5806, a hydraulic sensor 5808, and a control device main body 90.
The tank 5802 stores hydraulic oil.
The hydraulic pump 5804 is an electric pump that supplies the hydraulic oil sucked from the tank 5802 to the hydraulic motor 1604 via the supply flow path 5810 and the direction switching valve 5806 provided in the supply flow path 5810.
The supply amount of the hydraulic oil to the hydraulic motor 1604 by the hydraulic pump 5804 is controlled by the rotation control unit 94 described later, and the rotation speed of the hydraulic motor 1604 is controlled by controlling the supply amount of the hydraulic oil.

The direction switching valve 5806 is connected to the first and second supply / discharge ports 1604A and 1604B of the hydraulic motor 1604 via the forward rotation side supply flow path 5812 and the reverse rotation side supply flow path 5814.
The direction switching valve 5806 rotates the hydraulic motor 1604 in the normal direction by supplying hydraulic oil to the first supply / discharge port 1604A via the normal rotation side supply flow path 5812 under the control of the rotation control unit 94, and also causes the hydraulic motor 1604 to rotate in the normal direction. 2 The state in which the hydraulic oil discharged from the supply / discharge port 1604B via the reverse supply flow path 5814 is returned to the tank 5802 via the discharge flow path 5816, and the second supply / discharge port 1604B via the reverse side supply flow path 5814. The hydraulic motor 1604 is reversed by supplying hydraulic oil to the tank, and the hydraulic oil discharged from the first supply / discharge port 1604A via the normal rotation side supply flow path 5812 is returned to the tank 5802 via the discharge flow path 5816. It is configured to switch to the state.
The oil pressure sensor 5808 detects the oil pressure of the hydraulic oil supplied from the hydraulic pump 5804 to the hydraulic motor 1604 and supplies it to the rotation control unit 94 described later, and constitutes the oil pressure detection unit within the claims. ..

The control device main body 90 is composed of a computer 90A, and each computer 90A has a CPU, ROM, RAM, a hard disk device (or RAM disk device), a mouse, a keyboard, a display device, an input / output interface, and the like (not shown). There is.
The ROM is composed of, for example, a flash memory or the like, stores a control program or the like, and the RAM provides a working area.
The hard disk device constitutes a storage unit that stores various types of information.
In the present embodiment, the map storage unit 92 is configured by the storage unit.
As will be described later, the map storage unit 92 stores a map (correlation map) showing the correlation between the rotational speed of the hydraulic motor 1604 and the oil pressure of the hydraulic oil supplied to the hydraulic motor 1604.
The mouse and keyboard accept operations by the operator.
The display device displays various kinds of information.
The input / output interface is connected to the direction switching valve 5806 and the hydraulic pump 5804, and supplies a switching signal to the direction switching valve 5806 and a rotation control signal to the hydraulic pump 5804.
When the CPU executes the control program, the rotation control unit 94 and the switching control unit 96 are realized.

The map stored in the map storage unit 92 shows the rotation speed of the stirring casing dividing body 34A when stirring the sediment 42 deposited in the pile burial hole 40 by the stirring casing dividing body 34A, that is, the rotation of the hydraulic motor 1604. It shows the correlation between the speed and the oil pressure of the hydraulic oil supplied to the hydraulic motor 1604, and is created based on the data actually measured by stirring the sediment 42 having various properties.
Specifically, as shown in FIGS. 8A to 8D, the horizontal axis represents the rotation speed N (rpm) of the hydraulic motor 1604, and the vertical axis represents the hydraulic pressure P of the hydraulic oil. , The diagram of each map shows the regression equation showing the correlation, and a plurality of the regression equations are provided according to the properties of the sediment 42.
For example, in the maps of FIGS. 8 (A), (B), and (C), the inclination of the diagram gradually decreases in the order thereof, and the viscosity of the sediment 42 decreases in the above order. Shown. In such a case, the sediment 42 is composed of sediment having a substantially uniform particle size, and the proportion of gravel contained is low.
Further, in the map of FIG. 8D, the oil pressure P rises at a constant inclination as the rotation speed N increases, the inclination suddenly increases when the rotation speed N is exceeded, and when the rotation speed N is exceeded. Indicates that the slope is decreasing. In such a case, the sediment 42 often contains a relatively large amount of gravel (pebbles).
In the present embodiment, the case where the properties of the sediment 42 is the viscosity of the sediment 42 and the ratio of the gravel contained in the sediment 42 has been described. However, the properties of the sediment 42 include the sediment. Conventionally known influences on the correlation between the rotation speed of the stirring casing split 34A when stirring 42, that is, the rotation speed N of the hydraulic motor 1604 and the viscosity P of the hydraulic oil supplied to the hydraulic motor 1604. It includes various properties of sediment 42.

Based on the above map, the rotation control unit 94 controls the rotation of the hydraulic motor 1604 so that the oil pressure is in the vicinity of the upper limit value of the allowable range defined for the hydraulic motor 1604 and does not exceed the upper limit value.
Specifically, the rotation control unit 94 controls the rotation of the hydraulic pump 5804 and controls the flow rate of the hydraulic oil supplied to the hydraulic motor 1604 to control the rotation of the hydraulic motor 1604.

Further, the rotation control unit 94 selects a map based on the rotation speed N of the hydraulic motor 1604 and the oil pressure P detected by the oil pressure sensor 5808.
Specifically, the rotation control unit 94 initially controls the rotation of the hydraulic motor 1604 by the rotation control unit 94 based on a map that is considered to correspond to the properties of the earth and sand on which the pile burial hole 40 is formed. With the passage of time, if the relationship between the rotation speed N of the hydraulic motor 1604 and the detected oil pressure P deviates from the diagram of the initially selected map, the relationship between the rotation speed N of the hydraulic motor 1604 and the detected oil pressure P Reselect another map that matches more accurately with.
That is, when the properties of the sediment 42 are different from those initially expected, the rotation control unit 94 reselects a map close to the actual sediment 42.

Further, when the amount of change of the oil pressure P detected by the oil pressure sensor 5808 per unit time exceeds a predetermined amount of change threshold value, the rotation control unit 94 changes the rotation direction of the hydraulic motor 1604 from normal rotation. The rotation direction is switched to reverse rotation or from reverse rotation to normal rotation. Specifically, the rotation direction of the hydraulic motor 1604 is switched by switching the direction switching valve 5806.
This is because when the sediment 42 has a mixture of a large amount of gravel and a small amount of gravel, the amount of change in the hydraulic pressure P per unit time suddenly changes in the part where a large amount of gravel is distributed. This is because the rotation direction of the stirring casing divided body 34A is reversed from that of the previous one to promote stirring of the sediment 42 containing a large amount of gravel.

The switching control unit 96 is in a state of integrally rotating the braking blade 78, the first rotating blade 76, and the second rotating blade 62 (the braking blade 78, the first rotating blade 76, and the second rotating blade 62). A state in which the braking vane 78, the first rotary vane 76, and the second rotary vane 62 are separated and rotated (a state in which the braking vane 78, the first rotary vane 76, and the second rotary vane 62 are rotated together). The switching control of the switching unit 66 for switching between (a state in which they are not rotated together) and the switching unit 66 is performed.
The switching control of the switching unit 66 by the switching control unit 96 controls the hydraulic oil supply device 54 based on the comparison result between the oil pressure detected by the oil pressure sensor 5808 and the predetermined oil pressure threshold value to supply the hydraulic oil. This is done by supplying and stopping the supply of hydraulic oil from the device 54 to the actuator 86.
The specific operation of the switching control unit 96 will be described later.

Next, a method of using the stirring device 46 will be described with reference to the flowchart of FIG.
Since the excavation of the ground G around the buried pile 22 and the removal of the buried pile 22 by the excavation device 10 are the same as the procedures of FIGS. 11A to 11D described above, the description thereof will be omitted.
As shown in FIG. 11D, after the buried pile 22 is removed, sediment 42 having a heavy specific gravity and high viscosity is deposited in the lower part of the pile buried hole 40, and fine particles are deposited in the upper part of the pile buried hole 40. Muddy water 44, in which the soil floats and has a light specific gravity and low viscosity, is accumulated (step S10).
Here, as shown in FIG. 1, the existing rotary drive unit 16, the upper end casing divided body 28, the plurality of intermediate casing divided bodies 30 and 32, and the stirring casing divided body 34 are removed.
Then, a plurality of rotary drive units 16A provided with a water pipe, a hydraulic oil pipe, and a solidifying material pipe, a water supply pipe 48, a hydraulic oil supply pipe 50, and an upper end casing divided body 28A provided with a solidifying material supply pipe 52. The intermediate casing divided bodies 30A and 32A and the stirring casing divided body 34A (stirring device 46) are replaced to assemble the casing 18A (step S12).
Further, the water supply device 20, the hydraulic oil supply device 54, and the solidifying material supply device 56 are connected to the water pipe and the hydraulic oil pipe of the rotary drive unit 16A via the water supply hose 21, the hydraulic oil hose 55, and the solidifying material hose 57, respectively. , The water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 of the upper end casing split 28A are connected to the water pipe, the hydraulic oil pipe, and the solidifying material pipe of the rotary drive unit 16A while being connected to the solidifying material pipe. Connect (step S14).

At this time, the hydraulic oil supply device 54 is inactive, the hydraulic oil is not supplied to the actuator 86, the contact member 88 is located at the retracted position, and the first rotary vane 76 is attached to the stirring casing split body 34A. On the other hand, it is in a rotatable state (step S16). In other words, the braking vanes 78 and the first rotary vanes 76 and the second rotary vanes 62 do not rotate together.
Then, the rotation control device 58 starts operation, and the casing 18A is inserted into the pile embedding hole 40 by feeding out the wire 1212 of the crane 12 while rotating the casing 18A by the rotation driving unit 16A (step). S18).
At this time, the operator operates the water supply device 20 to supply water from the water supply device 20 and inject water from the water injection hole 70.
The stirring device 46 located at the lower end of the casing 18A enters the sediment 42 while rotating through the muddy water 44 due to the weight of the casing 18A and the rotational force of the rotary drive unit 16A, and is deposited by the water injected from the water injection hole 70. It moves toward the bottom of the pile burial hole 40 while diffusing the earth and sand 42.
The rotation speed N of the hydraulic motor 1604 controlled by the rotation control device 58 moves toward the bottom of the pile burial hole 40 while the stirring device 46 diffuses the sediment 42 by the water injected from the water injection hole 70. The rotation speed N is sufficient, and the value is set in advance.
When the agitator 46 enters the inside of the sediment 42 over the entire length and reaches the bottom of the pile burial hole 40, the water supply by the water supply device 20 is stopped, and the wire 1212 of the crane 12 is maintained while the casing 18A is rotating. (Step S20).

Then, the operator operates the solidifying material supply device 56 while maintaining the rotation of the casing 18A to operate the solidifying material supply device 56, and injects the solidifying material from the solidifying material injection hole 72 to inject the solidifying material into the pile burial hole 40. The supply of the solidifying material to the bottom is started (step S22).
Here, the supply amount of the solidifying material is appropriately set according to the target strength of the ground G of the pile burial hole 40.

Then, the rotation control unit 94 sets the rotation speed N of the hydraulic motor 1604 based on the selected map corresponding to the soil properties of the pile burial hole 40 in advance, and the hydraulic motor 1604 rotates at the rotation speed N. The hydraulic pump 5804 is controlled so as to (step S24).
As a result, the sediment 42 is agitated by rotating the plurality of second rotary blades 62 integrally with the rotation of the casing 18A (casing casing division 34A for agitation).
On the other hand, since the braking blade 78 is located in the highly viscous sediment 42, the braking blade 78 does not rotate integrally with the second rotating blade 62 and has a rotation speed slower than the rotation speed of the second rotating blade 62. Rotate.
Therefore, the first rotary vane 76 connected to the braking vane 78 via the rotary shaft 74 also rotates integrally with the braking vane 78 at a rotational speed slower than the rotational speed of the second rotary vane 62. In other words, the braking blade 78 brakes the rotation of the first rotating blade 76.
That is, the sediment 42 is agitated by both the plurality of second rotary blades 62 having a high rotation speed and the plurality of first rotary blades 76 having a slow rotation speed, thereby promoting the agitation of the sediment 42. , The solidifying material injected from the solidifying material injection hole 72 and the sediment 42 are efficiently and uniformly mixed.
Then, while maintaining the rotation of the casing 18A and supplying the solidifying material, the stirring device 46 is moved upward by starting the winding of the wire 1212 by the crane 12, and the stirring device 46 is moved upward from the lower part to the upper part of the pile burial hole 40. The sediment 42 and the solidifying material are mixed toward the above (step S26).

Next, the rotation control unit 94 determines whether or not the oil pressure P detected by the oil pressure sensor 5808 matches the rotation speed N of the hydraulic motor 1604 with reference to the diagram of the currently selected map, that is, It is determined whether or not the currently selected map is valid (step S28).
If step S28 is negative, another map is reselected based on the current rotational speed N of the hydraulic motor 1604 and the oil pressure P detected by the oil pressure sensor 5808 (step S30).
If step S28 is affirmative, the process proceeds to the next step S32.

Next, the rotation control unit 94 determines whether or not the amount of change of the oil pressure P detected by the oil pressure sensor 5808 per unit time exceeds a predetermined change amount threshold value (step S32).
If step S32 is affirmative, the rotation control unit 94 operates the direction switching valve 5806 to reverse the rotation direction of the hydraulic motor 1604 (step S34).
If step S32 is negative, the process proceeds to the next step S36.

When the braking blade 78 eventually escapes from the highly viscous sediment 42 and enters the low-viscosity muddy water 44 as the stirring device 46 moves upward, the braking of the first rotating blade 76 by the braking blade 78 is released.
Here, the switching unit 66 is controlled by the switching control unit 96.
In the state where the braking blade 78 is braked by the sediment 42, the first rotary blade 76 and the braking van 78 rotate following the sediment 42 moved by the rotation of the second rotary blade 62, but the first rotary blade Since the 76 is braked by the braking blades 78, the load of the hydraulic motor 1604 that rotates the casing 18A is high, and the oil pressure P detected by the oil pressure sensor 5808 is a high oil pressure P1.
When the braking blade 78 moves from the sediment 42 into the muddy water 44, the braking of the first rotary blade 76 by the braking blade 78 becomes ineffective, and the second rotary vane 62 follows the sediment 42 moved by the rotation of the second rotary blade 62. The 1-turn vane 76 and the braking vane 78 rotate, but since the 1st rotary vane 76 is not braked by the braking vane 78, the 1st rotary vane 76 and the braking vane 78 tend to rotate, so that the casing 18A is rotated. The load of the hydraulic motor 1604 is reduced, and the hydraulic pressure P detected by the hydraulic sensor 5808 is a hydraulic pressure P2 that is lower than the hydraulic pressure P1 in the state where the braking blade 78 is being braked by the sediment 42.
Therefore, a first threshold value Pr1 (hydraulic threshold value) smaller than the oil pressure P1 and larger than the oil pressure P2 is set, and it is determined whether or not the oil pressure P is lower than the first threshold value Pr1 (step). S36).

If step S36 is negative, the process returns to step S28.
If step S36 is affirmative, the switching control unit 96 supplies hydraulic oil by controlling the hydraulic oil supply device 54, operates the actuator 86, and moves the contact member 88 from the retracted position to the contact position ( Step S38).
As a result, the first rotary vane 76 is engaged with the contact member 88, so that the first rotary vane 76 rotates integrally with the casing 18A (casing casing dividing body 34A for stirring), in other words, the braking vanes 78 and Since the first rotary vane 76 and the second rotary vane 62 are in a state of co-rotating, the rotational speed of the first rotary vane 76 and the rotational speed of the second rotary vane 62 match.
Therefore, the sediment 42 in the vicinity of the first rotary blade 76 and the second rotary blade 62 moves following the rotation of the first rotary blade 76 and the second rotary blade 62, so that the rotation speed of the first rotary blade 76 Is slower than the rotation speed of the second rotary blade 62, and the stirring of the sediment 42 is suppressed as compared with the case where.
Therefore, when the contact member 88 is moved from the retracted position to the contact position, the stirring device 46 is reciprocated while being reciprocated up and down by alternately repeating hoisting and feeding by the crane 12 while maintaining the rotation of the casing 18A. By gradually moving the device 46 upward, the agitation of the sediment 42 is promoted, and the sediment 42 and the solidifying material are efficiently mixed (step S40).
That is, since the casing 18A is reciprocated up and down, the first rotary blade 76 and the second rotary blade 62 rotate in a region where the highly viscous sediment 42 and the less viscous muddy water 44 are mixed, so that the sediment 42 And muddy water 44 will be agitated efficiently.

As described above, when it is detected in step S36 that the braking blade 78 has moved from the accumulated earth and sand 42 into the muddy water 44 and the braking of the first rotating blade 76 by the braking blade 78 is not effective, step S38 The braking vanes 78, the first rotary vanes 76, and the second rotary vanes 62 rotate together.
This is because the braking vanes 78, the first rotary vanes 76, and the second rotary vanes 62 can rotate independently when the stirring casing split 34A moves near the boundary between the muddy water 44 and the sediment 42. It has been empirically revealed that the rotation of the first rotary vane 76 and the second rotary vane 62 becomes unstable if left as it is, and here, the braking vane 78, the first rotary vane 76, and the first rotary vane 76 are used. This is because it has been empirically revealed that the first rotary blade 76 and the second rotary blade 62 rotate stably when the state is switched so that the two rotary blades 62 rotate together.

Eventually, the stirring device 46 escapes from the sediment 42 and moves into the muddy water 44, in other words, all of the braking blade 78, the first rotary blade 76, and the second rotary blade 62 escape from the sediment 42 and enter the muddy water 44. Moving.
Here, the switching unit 66 is again controlled by the switching control unit 96.
That is, when all of the braking vanes 78, the first rotary vanes 76, and the second rotary vanes 62 move into the muddy water 44, the braking vanes 78, the first rotary vanes 76, and the second rotary vanes 62 are in the muddy water 44 having low viscosity. Since it rotates, the load of the hydraulic motor 1604 that rotates the casing 18A is further reduced, and the oil pressure P detected by the oil pressure sensor 5808 becomes the oil pressure P3 that is lower than the oil pressure P2.
Therefore, a second threshold value Pr2 (hydraulic threshold value) smaller than the oil pressure P2 and larger than the oil pressure P3 is set, and it is determined whether or not the oil pressure P is lower than the second threshold value Pr2 (step). S42).
The first threshold value Pr1 and the second threshold value Pr2 may be set after stirring the sediment 42 having various properties using the stirring device 46 and actually measuring the flood pressures P2 and P3.
If step S42 is negative, step S42 is repeated.
If step S42 is affirmative, the switching control unit 96 stops the supply of hydraulic oil by controlling the hydraulic oil supply device 54, and moves the contact member 88 from the contact position to the retracted position by the actuator 86 (step). S44).
As a result, the engagement between the first rotary blade 76 and the contact member 88 is released, so that the first rotary blade 76 becomes rotatable with respect to the stirring casing split body 34A. In other words, the braking blade 78, the first rotary blade 76, and the second rotary blade 62 do not rotate together.
Then, while maintaining the vertical reciprocating movement of the stirring device 46 by the crane 12, the stirring device 46 is pulled up at a low speed, the rotation of the stirring device 46 is maintained, and the injection of the solidifying material is maintained.
In this case, the braking of the braking vanes 78 is not effective in the muddy water 44, and the first rotating vanes 76 and the braking vanes 78 rotate following the muddy water 44 that moves by the rotation of the second rotating vanes 62 (casing 18A). However, the first rotary vane 76 and the second rotary vane 62 do not rotate integrally, but rotate independently of each other, and the rotational speed of the first rotary vane 76 and the rotational speed of the second rotary vane 62 Will be different.
Therefore, while the first rotary blade 76 and the second rotary blade 62 reciprocate up and down, the first rotary blade 76 and the second rotary blade 62 rotate at different rotational speeds, so that the muddy water 44 and the solidifying material are efficiently stirred. As a result, stirring of the muddy water 44 and the solidifying material is promoted, and therefore, the solidifying material and the muddy water 44 injected from the solidifying material injection hole 72 are efficiently and uniformly mixed.
The agitator 46 reaches the upper part of the pile burial hole 40, determines whether or not the mixed solidifying material and the muddy water 44 have reached the upper end of the pile burial hole 40 (step S46), and if step S46 is negative, the step S46 is repeated, and if step S46 is affirmative, the stirring device 46 is pulled out above the pile burial hole 40, and a series of operations is completed (step S48).
With the passage of time, the solidifying material mixed with the sediment 42 is solidified at the lower part of the pile burial hole 40, and the muddy water 44 mixed with the solidifying material is solidified at the upper part of the pile burying hole 40. The ground of 40 is improved to have the same strength and rigidity as the surrounding ground G.

According to the present embodiment, when the braking blade 78 is located in the highly viscous sediment 42, the plurality of second rotary blades 62 having a high rotation speed and the plurality of first rotary blades 76 having a slow rotation speed are used. Both of the above promote the stirring of the sediment 42 deposited in the pile burial hole 40 from which the buried pile 22 has been removed, so that the solidified material supplied from the solidifying material supply unit and the sediment 42 are efficiently and uniformly mixed. ..
Further, the braking vanes 78 are located in the less viscous muddy water 44, and the first rotary vanes 76 and the second rotary vanes 62 are located in the highly viscous sediment 42, and therefore the first rotary vanes 76 and the second rotary vanes 76 and the second. Even when the rotary blades 62 rotate together and the rotation speeds of the rotary blades 76 and 62 match, the agitator 46 is moved up and down to deposit the buried pile 22 in the pile burial hole 40. Since the agitation of the earth and sand 42 is promoted, the solidifying material supplied from the solidifying material supply unit and the sediment 42 are efficiently and uniformly mixed.
Therefore, by spreading the solidifying material over the entire sediment 42 deposited in the pile burial hole 40, it is advantageous to improve the ground after the removal of the burial pile 22 to have the same strength and rigidity as the surrounding ground G.
Further, the ground can be improved by using the drilling device 10 that excavates the ground G in order to remove the buried pile 22, and other heavy machinery different from the conventional drilling device 10 becomes unnecessary.
That is, by exchanging the casing 18A of the drilling rig 10, the stirring device 46 can be rotated and used by the drilling rig 10, and the ground can be improved without using other heavy machinery different from the conventional drilling rig 10. This can be done, and the time required for ground improvement can be significantly shortened, which is advantageous in reducing the construction cost.

Further, in the present embodiment, the rotation control of the hydraulic motor 1604 for rotating the excavation casing split body 34 is controlled in advance for the rotation of the hydraulic motor 1604 corresponding to each of a plurality of types of sediments 42 having different properties. Based on the map showing the correlation between the speed N and the oil pressure of the hydraulic oil supplied to the hydraulic motor 1604, the oil pressure is set to be close to the upper limit value of the permissible range set for the hydraulic motor 1604 and not to exceed the upper limit value.
Therefore, the rotation speeds of the first rotary blade 76 and the second rotary blade 62 can be maximized according to the properties of the sediment 42 to be agitated without affecting the durability and life of the hydraulic motor 1604. ..
Therefore, it goes without saying that the solidifying material and the sediment 42 can be efficiently and uniformly mixed, and the time required for ground improvement can be significantly shortened, which is more advantageous in reducing the construction cost.

Further, the map stored in the map storage unit 92 is created based on the data actually measured by stirring the sediment 42 having various properties by using the stirring device 46.
Then, if a large number of such data are actually measured, more maps are created and stored in the map storage unit 92, the rotation control of the hydraulic motor 1604 for rotating the excavation casing division 34 can be controlled by the sediment 42. It can be controlled more finely according to the properties, and is more advantageous in maximizing the rotation speed of the first rotary blade 76 and the second rotary blade 62 according to the properties of the sediment 42 to be agitated.
Further, by actually measuring a large number of data and creating a large number of maps, the braking vanes 78, the first rotary vanes 76, and the second are so that the sediment 42 can be efficiently agitated based on the maps of those maps. It is advantageous in designing the number and dimensions of the rotary blades 62.

Further, in the present embodiment, the rotation control unit 94 selects the map based on the rotation speed N of the hydraulic motor 1604 and the oil pressure P detected by the oil pressure sensor.
Therefore, when the stirring device 46 moves from the lower side to the upper side of the pile burial hole 40 while stirring the accumulated earth and sand 42, the relationship between the rotation speed N of the hydraulic motor 1604 and the detected oil pressure P is initially selected with the passage of time. If it deviates from the map diagram, the map that matches the relationship between the rotation speed N of the hydraulic motor 1604 and the detected oil pressure P more accurately is selected again, so it corresponds to the properties of the actual system sediment. Therefore, the rotation speed N of the hydraulic motor 1604 can be made appropriate, and the solidifying material and the sediment 42 can be mixed efficiently and uniformly without affecting the durability and the life of the hydraulic motor 1604. It will be advantageous, and it will be more advantageous in shortening the construction period of the ground improvement work.

Further, in the present embodiment, the switching control of the switching unit by the switching control unit is performed based on the comparison result between the oil pressure P detected by the oil pressure sensor and the predetermined oil pressure thresholds Pr1 and Pr2. However, it may be as follows.
That is, the operator winds up the wire 1212 by the crane 12 that the braking blade 78 has moved from the accumulated sediment 42 to the muddy water 44, or that the entire stirring device 46 has moved from the accumulated sediment 42 to the muddy water 44. That is, the stirring device 46 determines based on the moving distance pulled up from the bottom, and the operator operates the hydraulic oil supply device 54 to supply or release the hydraulic oil, operate the actuator 86, and contact the contact member. The 88 may be moved from the retracted position to the contact position, or may be moved from the contact position to the retracted position.
However, according to the present embodiment, the switching control of the switching unit 66 can be automatically performed by the switching control unit 96, so that the operator does not have to perform complicated operations and the work efficiency is improved. It becomes advantageous in.

Further, in the present embodiment, the rotation control unit 94 sets the hydraulic motor 1604 when the amount of change of the oil pressure P detected by the oil pressure detection unit per unit time exceeds a predetermined change amount threshold value. The direction of rotation is reversed.
Therefore, for example, when a portion where a large amount of gravel is distributed and a portion where a small amount of gravel is distributed are mixed in the sediment 42, the amount of change in the hydraulic pressure P per unit time is rapid in the portion where a large amount of gravel is distributed. By reversing the stirring casing divided body 34A, the first rotary blade 76 and the second rotary blade 62 are reversed, and the movement of these rotary blades promotes stirring of the sediment 42 containing a large amount of gravel. This is more advantageous in efficiently and uniformly mixing the solidifying material and the sediment 42.

Further, the rotating shaft 74 may be rotatably supported by a plurality of stays projecting from the inner peripheral surface of the stirring casing divided body 34A, but as in the present embodiment, the plurality of first rotating blades 76 may be rotatably supported. If a connecting ring 80 is provided to connect the radial outer ends of the casing and a bearing 64 is provided to support the connecting ring 80 so as to be rotatable and immovable in the axial direction, a large space inside the casing 18A can be secured and deposited. It is advantageous for efficiently mixing the earth and sand 42 and the solidifying material to improve the ground efficiently.

Further, according to the present embodiment, the first rotary vane 76, the braking vane 78, and the second rotary vane 62 are each formed of a steel flat plate having a constant width and an integral length, and the width direction is the axial direction. Since the length direction is arranged toward the radial direction of the stirring casing dividing body 34A, the first rotating blade 76, the braking blade 78, and the second rotating blade are arranged in the circumferential direction inside the stirring casing dividing body 34A. The 62 has a large area, which is advantageous in efficiently mixing the sediment 42 and the solidifying material to improve the ground efficiently.

Further, according to the present embodiment, the switching portion 66 is provided with an actuator 86 attached to the inner peripheral surface of the stirring casing dividing body 34A, a retracted position separated from the first rotary blade 76 by the actuator 86, and a second position. It is configured to include a contact member 88 that comes into contact with the first rotary blade 76 and moves between the contact position that abuts the first rotary blade 76 and rotates the first rotary blade 76 integrally with the casing dividing body 34A for stirring.
Therefore, regardless of the rotation direction of the casing 18A, it is advantageous for the first rotary blade 76 to be reliably rotated integrally with the casing dividing body 34A for stirring, and the sediment 42 and the solidifying material are efficiently mixed to form the ground. It is advantageous for efficient improvement.

Further, according to the present embodiment, the stirring casing split body 34A is a portion of the casing 18A directly above the excavation casing split body 34 at the lower end of the casing 18A of the excavation device 10 suspended and rotationally driven by the crane 12. Since it is detachably attached to (intermediate casing divided body 32A), it is advantageous in simplifying the work of attaching and detaching the stirring device 46 to the excavating device 10.

In the embodiment, the rotation control of the hydraulic motor 1604 by the rotation control unit 94 is performed based on a map showing the correlation between the rotation speed N of the hydraulic motor 1604 and the oil pressure P of the hydraulic oil supplied to the hydraulic motor 1604. Although the case where this is performed has been described, instead of the map, it may be performed based on a regression equation showing the correlation between the rotation speed N of the motor 1604 and the oil pressure P of the hydraulic oil.
In this case, the rotation control unit 94 selects a plurality of regression equations created based on the properties of the soil based on the rotation speed N of the hydraulic motor 1604 and the oil pressure P detected by the oil pressure sensor.

Further, in the present embodiment, the existing upper end casing dividing body 28, the plurality of intermediate casing dividing bodies 30 and 32, the stirring casing dividing body 34, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 The case where the casing 18A is assembled by exchanging the upper end casing dividing body 28A provided with the above, the plurality of intermediate casing dividing bodies 30A and 32A, and the stirring casing dividing body 34A (stirring device 46) has been described.
However, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 may be attached to the existing upper end casing divided body 28 and the plurality of intermediate casing divided bodies 30 and 32. For example, it becomes unnecessary to replace the existing upper-end casing divided body 28 and the plurality of intermediate casing divided bodies 30 and 32, which is advantageous in shortening the working time.

Further, in the present embodiment, the water supply pipe 48 and the solidifying material supply pipe 52 are provided in each of the upper end casing dividing body 28A, the plurality of intermediate casing dividing bodies 30A and 32A, and the stirring casing dividing body 34A (stirring device 46). Have been described in the case where they are provided independently.
However, the solidifying material supply pipe 52 may be omitted, and the water supply pipe 48 may also be used as the solidifying material supply pipe 52.
In this case, the solidifying material pipeline of the rotary drive unit 16A and the solidifying material hose 57 are omitted, and between the end of the water supply hose 21 and the water supply device 20 and the solidifying material supply device 56. If a switching unit is provided, the switching unit switches between the water supplied from the water supply device 20 and the solidifying material supplied from the solidifying material supply device 56 and supplies the water to the end of the water supply hose 21. Good.
In this way, the solidifying material supply pipe 52 of the casing divided body 34A for stirring can be omitted, which is of course advantageous in simplifying the configuration of the stirring device 46 and reducing the cost. Since the solidifying material supply pipe 52 of the remaining casing divided bodies 28A, 30A, and 32A, the solidifying material pipeline of the rotary drive unit 16A, and the solidifying material hose 57 can be omitted, the configuration of the excavator 10 is simplified. It is also advantageous in terms of conversion and cost reduction.

(Second Embodiment)
Next, the second embodiment will be described with reference to FIG.
In the following embodiments, the same parts and members as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, the description thereof is omitted, and the different parts are mainly described. To do.
In the first embodiment, the switching control of the switching unit 66 by the switching control unit 96 is performed based on the comparison result between the oil pressure detected by the oil pressure sensor 5808 and the predetermined oil pressure threshold value.
On the other hand, in the second embodiment, as shown in FIG. 10, a proximity sensor 98 is provided on the outer peripheral surface of the stirring casing dividing body 34 to detect the presence or absence of an object, that is, to detect the presence or absence of accumulated sediment. It was.
Then, based on the detection result of the proximity sensor 98, that is, when it is detected that the stirring casing dividing body 34 has moved from the sediment 42 to the muddy water 44, the switching control unit 96 performs switching control of the switching unit 66. It is the one that was made.
As the proximity sensor 98, various conventionally known sensors such as a capacitance sensor can be used.
In such a second embodiment, the same effect as that of the first embodiment is obtained.

(Third Embodiment)
Next, the third embodiment will be described with reference to FIG.
In the third embodiment, as shown in FIG. 11, a wire hoisting amount detecting unit 1220 for detecting the hoisting amount of the wire 1212 by the hoisting device of the crane 12 is provided.
Then, the switching control of the switching unit 66 by the switching control unit 96 is performed based on the comparison result between the winding amount of the wire 1212 detected by the winding amount detecting unit 1220 and the predetermined winding amount threshold value. ..
That is, the hoisting amount threshold value is set in advance as a hoisting amount sufficient for the stirring casing dividing body 34 to move from the sediment 42 to the muddy water 44, and the hoisting amount threshold value is, for example, the muddy water 44 and the sediment. The height from the bottom of the pile burial hole 40 at the boundary with the earth and sand 42 is actually measured or estimated and set.
In such a third embodiment, the same effect as that of the first embodiment is obtained.

10 Excavation device 12 Crane 1212 Wire 1220 Wire hoisting amount detection unit 16 Rotation drive unit 1604 Hydraulic motor 18 Casing 20 Water supply device (water supply unit)
21 Water supply hose (water supply unit)
22 Buried pile 34 Excavation casing split body 34A Casing casing split body 40 Pile burial hole 42 Sedimentary sediment 44 Muddy water 46 Stirrer 48 Water supply pipe (water supply section)
52 Solidifying material supply pipe (solidifying material supply section)
56 Solidifying material supply device (solidifying material supply unit)
57 Solidifying material supply hose (solidifying material supply unit)
58 Rotation control device 5804 Hydraulic pump 5808 Flood control sensor (flood detection unit)
60 Stirring blade 62 2nd rotary blade 64 Bearing 66 Switching part 74 Rotating shaft 76 1st rotating blade 78 Braking blade 80 Connecting ring 86 Actuator 88 Contact member 90 Control device body 90A Computer 92 Map storage unit 94 Rotation control unit 96 Switching control Part 98 Proximity sensor

Claims (12)

A stirrer that is used by replacing the excavation casing split at the lower end of the casing of the excavator that is suspended by a crane and rotationally driven by a hydraulic motor, and agitates the sediment and muddy water that accumulates in the pile burial hole and the solidifying material. There,
The stirring device is a tubular stirring casing split that is arranged with its axis oriented in the vertical direction, is removable from the casing portion directly above the drilling casing split body, and has a cutter for drilling at the outer peripheral portion of the lower end. A body, a stirring blade arranged inside the stirring casing divided body, a water supply unit for supplying water to the lower end of the stirring casing divided body, and the solidifying material at the lower end of the stirring casing divided body. A solidifying material supply unit for supplying and a rotation control unit for controlling the rotation of the hydraulic motor are provided.
The stirring blade extends along the axis and is immovable in the axial direction of the stirring casing divided body and is rotatably arranged on the axis, and the upper and lower intermediates of the rotating shaft. A plurality of first rotating blades extending outward in the radial direction of the rotating shaft from a portion spaced in the circumferential direction at a portion spaced from the portion to the lower portion in the longitudinal direction of the rotating shaft, and an upper portion of the rotating shaft. It has a plurality of braking blades extending outward in the radial direction of the rotation axis from locations spaced in the circumferential direction.
The stirring casing division is performed at a portion spaced from the upper and lower middle portions of the stirring casing split body in the axial direction at a portion spaced in the circumferential direction of the inner peripheral surface of the stirring casing split body. A plurality of second rotary blades extending inward in the radial direction of the body are provided so as to be displaced in the axial direction with respect to the first rotary blade.
Further, a switching unit is provided to switch the rotating shaft between a state in which the rotating shaft can be rotated with respect to the stirring casing divided body and a state in which the rotating shaft can be integrally rotated with the stirring casing divided body.
The rotation control of the hydraulic motor by the rotation control unit is performed on the rotation speed of the hydraulic motor and the hydraulic oil supplied to the hydraulic motor, which are prepared in advance corresponding to each of a plurality of types of sediments having different properties. Based on a map showing the correlation with the oil pressure of the above or a regression equation, the oil pressure is made to be in the vicinity of the upper limit value of the allowable range defined for the hydraulic motor and not to exceed the upper limit value.
A stirring device characterized in that. A hydraulic detection unit for detecting the hydraulic pressure of the hydraulic oil supplied to the hydraulic motor is provided.
The rotation control unit selects the map or the regression equation based on the rotation speed of the hydraulic motor and the oil pressure detected by the oil pressure detection unit.
The stirring device according to claim 1, wherein the stirring device is characterized by the above. A switching control unit for performing switching control of the switching unit is provided.
The switching control of the switching unit by the switching control unit is performed based on the comparison result between the oil pressure detected by the oil pressure detecting unit and the predetermined oil pressure threshold value.
2. The stirring device according to claim 2. A switching control unit for performing switching control of the switching unit is provided.
A proximity sensor is provided in the stirring casing divided body.
The switching control of the switching unit by the switching control unit is performed based on the detection result of the proximity sensor.
2. The stirring device according to claim 2. The stirring casing split body is suspended from the crane via a wire.
A winding amount detecting unit for detecting the winding amount of the wire is provided.
A switching control unit for performing switching control of the switching unit is provided.
The switching control of the switching unit by the switching control unit is performed based on a comparison result between the winding amount of the wire detected by the winding amount detecting unit and a predetermined winding amount threshold value.
2. The stirring device according to claim 2. The rotation control unit reverses the rotation direction of the hydraulic motor when the amount of change in the oil pressure detected by the oil pressure detection unit per unit time exceeds a predetermined change amount threshold value.
The stirring device according to any one of claims 2 to 5, characterized in that. A connecting ring for connecting the radial outer ends of the first rotary vanes is provided for each of the plurality of first rotary vanes extending from the same position in the longitudinal direction of the rotary shaft.
A bearing that supports the connecting ring so as to be rotatable and immovable in the axial direction is provided on the inner peripheral surface of the stirring casing.
The stirring device according to any one of claims 1 to 6, characterized in that. The first rotary vane, the braking vane, and the second rotary vane are each formed of a flat plate having a constant width and an integral length, and the width direction is directed to the axial direction and the length direction is the stirring casing. Arranged in the radial direction of the split body,
The stirring device according to any one of claims 1 to 7, wherein the stirring device is characterized. The switching portion includes an actuator attached to the inner peripheral surface of the stirring casing split body, a retracted position separated from the first rotary blade by the actuator in the axial direction of the stirring casing split body, and the above. It is configured to include a contact member that abuts on the first rotary vane in the circumferential direction of the axis and moves between the contact position that abuts the first rotary vane and rotates the first rotary vane integrally with the stirring casing divided body. Yes,
The stirring device according to any one of claims 1 to 8, wherein the stirring device is characterized. A tubular stirring casing split body arranged with its axis oriented in the vertical direction and both ends open in the axial direction, a stirring blade arranged inside the stirring casing split body, and the stirring casing split body. A stirrer equipped with a solidifying material supply unit that supplies the solidifying material to the inside of the body is provided.
The stirring blade extends along the axis and is immovable in the axial direction of the stirring casing divided body and is rotatably arranged on the axis, and the upper and lower intermediates of the rotating shaft. A plurality of first rotating blades extending outward in the radial direction of the rotating shaft from a portion spaced in the circumferential direction at a portion spaced from the portion to the lower portion in the longitudinal direction of the rotating shaft, and an upper portion of the rotating shaft. It has a plurality of braking blades extending outward in the radial direction of the rotation axis from locations spaced in the circumferential direction.
The stirring casing division is performed at a portion spaced from the upper and lower middle portions of the stirring casing split body in the axial direction at a portion spaced in the circumferential direction of the inner peripheral surface of the stirring casing split body. A plurality of second rotary blades extending inward in the radial direction of the body are provided so as to be displaced in the axial direction with respect to the first rotary blade.
Further, a switching unit is provided to switch the rotating shaft between a state in which the rotating shaft can be rotated with respect to the stirring casing divided body and a state in which the rotating shaft can be integrally rotated with the stirring casing divided body.
A hydraulic motor for rotating the stirring casing split body is provided.
When the braking blade is located in highly viscous sediment, the rotating shaft is switched to a rotatable state by a switching portion, and the stirring casing divided body is rotated while supplying a solidifying material.
When the braking blade is located in muddy water having low viscosity, the rotating shaft is switched to a state in which the rotating shaft can be integrally rotated with the stirring casing split body by the switching portion, and the stirring casing split body is supplied while supplying a solidifying material. To rotate and move the stirrer up and down,
Correlation between the rotation speed of the hydraulic motor and the oil pressure of the hydraulic oil supplied to the hydraulic motor, which is created in advance corresponding to each of the plurality of types of sediments having different properties in the rotation control of the hydraulic motor. Based on the map showing the above or the regression equation, the hydraulic pressure is not close to the upper limit value of the allowable range defined for the hydraulic motor and does not exceed the upper limit value.
A method of improving the ground of a pile burial hole, which is characterized by this. When the stirring device is located in muddy water having low viscosity, the rotating shaft is switched to a state in which the rotating shaft can rotate with respect to the stirring casing split body by the switching portion, and the stirring casing split while supplying the solidifying material. The stirring device was moved up and down while rotating the body.
The method for improving the ground of a pile burial hole according to claim 10. The stirring casing split body is detachably attached to the casing portion directly above the excavation casing split body at the lower end of the casing of the excavation device suspended and rotationally driven by a crane.
The method for improving the ground of a pile burial hole according to claim 10 or 11.

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