JP7374428B2 - Ground improvement method for stirring equipment and pile burial holes - Google Patents

Description

The present invention relates to an agitation device used for backfilling a pile burial hole remaining after the removal of buried piles, and a ground improvement method for a pile burial hole.

When rebuilding a building or structure, after removing the building or structure, it is necessary to pull out the existing buried piles that were buried underground, and backfill the pile holes that remain after they are pulled out.
Conventionally, when removing buried piles, an excavation device 10 as shown in FIG. 12 has been used.
The excavation rig 10 includes a crane 12, a leader 14, a rotation drive section 16, a casing 18, and a water supply device 20.
The crane 12 includes a lower traveling body 1202, an upper rotating body 1204 that is rotatably provided on the upper part of the lower traveling body 1202, and a boom 1206 that is provided on the upper rotating body 1204 so as to be able to rise and fall in the vertical direction and to be extendable and retractable. It is equipped with
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 along the boom 1206 to the upper revolving body 1204 and connected to a hoisting device (not shown) of the upper revolving body 1204. The wire 1212 is wound up and let out.
The leader 14 is swingably suspended from a 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 that is rotationally driven by the hydraulic motor 1604.
The case 1602 has a guided portion 1608 that is guided by the leader 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 feeding out the wire 1212. direction.
The casing 18 is constructed by connecting the upper and lower ends of each cylindrical casing segment 26 in the axial direction via bolts, and in this example, the casing 18 has four casing segments 26 connected to each other. It is composed of
Each casing segment 26 is formed to have an inner diameter larger than the outer diameter of the buried pile 22.
The uppermost casing division 26 is the upper end casing division 28 having a connecting portion 2802 that is detachably connected to the rotating shaft 1606 so as to be able to rotate integrally therewith.
The lowest casing division 26 is an excavation casing division 34, and an excavation cutter (not shown) is attached to the excavation casing division 34 at intervals along the lower end of its outer circumferential surface. It is worn.
The casing segments 26 that connect the upper end casing segment 28 and the excavation casing segment 34 are intermediate casing segments 30, 32.
Further, a water supply pipe (not shown) is provided over the entire length of the casing 18 from the rotation shaft 1606 of the rotation drive unit 16, and a water injection hole (not shown) is provided at the lower end of the excavation casing 18 to inject water from the water supply pipe. It is formed.
The water supply device 20 supplies water to a water supply pipe, and the water supply device 20 and the water supply pipe are a pipe (not shown) provided in the rotation drive unit 16 and a water supply hose connected to this pipe. 21.

The procedure for removing the buried pile 22 using the excavation 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, a support frame 24 is installed around the buried pile 22, and the excavation device 10 is moved and installed near the buried pile 22.
The upper revolving body 1204 of the crane 12 is rotated and the boom 1206 is extended to position the casing 18 so that it is located above the buried pile 22 and the axis of the casing 18 coincides with the axis of the buried pile 22. .
At this time, the lower end of the leader 14 is placed on the upper part of 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 with the casing 18 by letting out the wire 1212 of the crane 12 while rotating the casing 18 by the rotation drive 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 segment 34.
As a result, as shown in FIG. 13(A), the ground G is loosened by the water injected from the water injection hole and becomes muddy, and the excavated casing divided body 34 is pushed into the ground G by the weight and rotational force of the casing 18. The excavator enters the ground G outside the buried pile 22 in the radial direction and excavates it in a cylindrical shape.
Eventually, as shown in FIG. 13(B), when the tip of the excavated casing segment 34 reaches approximately the same position as the lower end of the buried pile 22, the casing 18 is rotated by winding up the wire 1212 of the crane 12. Pull it out from the ground G.
As a result, as shown in FIG. 13(C), 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 excavated hole 36 are cut off. Between the two, muddy water 38 remains, which is a mixture of injected water and excavated earth and sand.
Next, a wire (not shown) is wound around the buried pile 22, and one end of the above-ground side of the wire 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 burying hole 40 is formed in the ground G from which the buried pile 22 was pulled out from the excavated hole 36, and muddy water 38 is collected in this pile burying hole 40.
This muddy water 38 settles over time, so sediment 42 with a heavy specific gravity and high viscosity is deposited in the lower part of the pile burial hole 40, while fine-grained soil floating in the upper part of the pile burial hole 40 has a low specific gravity and a high viscosity. This results in muddy water 44 with low water being accumulated.

Here, a solidifying material, which is a self-hardening solution, is injected into the pile burying hole 40 and stirred by air blowing to solidify the mud, thereby improving the ground of the pile burying hole 40 in the same way as the surrounding ground G. will be carried out.
Alternatively, solidifying material such as cement milk is injected into the pile burying hole 40 with a screw auger and stirred, thereby solidifying muddy water and improving the ground of the pile burying hole 40 in the same manner as the surrounding ground G.

Japanese Patent Application Publication No. 2015-183501

However, in the above conventional technology, when stirring by air blow is used, if the viscosity of the sediment 42 accumulated in the pile embedding hole 40 is high, it is difficult to sufficiently stir the entire sediment 42 and the solidification material, There is room for improvement in distributing the solidification 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. be.
Further, when using a screw auger, the screw auger, which is a heavy machine separate from the excavation equipment 10, must be prepared, which has the disadvantage of increasing construction costs.
The present invention has been devised in view of the above-mentioned circumstances, and an object of the present invention is to spread the solidification material throughout the piled earth and sand accumulated in the pile burial hole, thereby improving the surrounding ground after the buried pile is removed. It is an object of the present invention to provide a stirring device and a ground improvement method for pile burial holes, which are advantageous in improving the strength and rigidity to the same level as the ground, and are advantageous in reducing construction costs.

In order to achieve the above object, the present invention is used to replace the excavation casing division body at the lower end of the casing of an excavation equipment that is suspended by a crane and rotationally driven by a hydraulic motor, and is used to replace the excavation casing division body at the lower end of the casing of an excavation equipment that is suspended by a crane and rotationally driven by a hydraulic motor. A stirring device for stirring muddy water and solidified material, the stirring device being arranged with its axis directed in the vertical direction, removable from a portion of the casing directly above the excavation casing divided body, and having a lower end outer peripheral portion. a cylindrical stirring casing division body having a cutting cutter for excavation; a stirring blade disposed inside the stirring casing division body; and a water supply unit supplying water to a lower end of the stirring casing division body. , a solidifying material supply section that supplies the solidifying material to the lower end of the stirring casing division body, and a rotation control section that controls rotation of the hydraulic motor, and the stirring blade extends along the axis. and a rotating shaft that is immovable in the axial direction of the stirring casing segment and rotatably arranged on the axis, and an interval in the longitudinal direction of the rotating shaft from an upper and lower middle part to a lower part of the rotating shaft. a plurality of first rotary vanes extending radially outward of the rotary shaft from circumferentially spaced positions at the upper part of the rotary shaft; and a plurality of brake vanes extending radially outward, the inner circumferential surface of the stirring casing division being spaced apart in the axial direction from the upper and lower intermediate parts to the lower part of the stirring casing division. A plurality of second rotary vanes extending radially inward of the stirring casing segment are provided at circumferentially spaced locations and are shifted in position in the axial direction with respect to the first rotary vane, and further , a switching unit is provided for switching between a state in which the rotating shaft is rotatable relative to the stirring casing segment and a state in which the rotating shaft is rotatable integrally with the stirring casing segment; The rotation control of the hydraulic motor is performed based on a correlation between the rotational speed of the hydraulic motor and the oil pressure of the hydraulic oil supplied to the hydraulic motor, which is created in advance in correspondence with each of the plurality of types of accumulated sediment having different properties. The hydraulic pressure is set to be close to an upper limit value of an allowable range defined for the hydraulic motor and not to exceed the upper limit value based on a map or regression equation showing the relationship.
The present invention also provides a cylindrical stirring casing segment arranged with its axis directed in the vertical direction and open at both ends in the axial direction, and a stirring blade disposed inside the stirring casing segment. , a stirring device including a solidifying material supply section that supplies a solidifying material into the inside of the stirring casing divided body, the stirring blade extending along the axis, and the stirring blade extending along the axis of the stirring casing divided body; A rotary shaft that is immovable in the direction and rotatably arranged on the axis, and a rotary shaft that is spaced apart in the circumferential direction from the upper and lower intermediate portions of the rotary shaft to the lower part thereof at positions that are spaced apart in the longitudinal direction of the rotary shaft. a plurality of first rotary vanes extending radially outward of the rotary shaft from a location where the rotary shaft is located; and a plurality of brake vanes extending radially outward of the rotary shaft from positions spaced apart in the circumferential direction at an upper portion of the rotary shaft. and at locations spaced apart in the axial direction from the upper and lower intermediate portions of the stirring casing segmented body to the lower part, and at locations spaced apart in the circumferential direction of the inner circumferential surface of the stirring casing segmented body, A plurality of second rotary blades extending radially inward of the stirring casing division body are provided to be shifted in position in the axial direction with respect to the first rotary blade, and further, the rotation shaft is connected to the stirring casing division body. A switching unit is provided for switching between a state in which the rotating shaft is rotatable with respect to the stirring body and a state in which the rotating shaft is rotatable integrally with the stirring casing divided body, and a hydraulic motor is provided for rotating the stirring casing divided body, When the brake blade is located in the highly viscous sediment, the switching unit switches the rotating shaft to a rotatable state, and rotates the stirring casing segment while supplying the solidification material, so that the brake blade When located in muddy water with low viscosity, the switching unit switches the rotating shaft to a state where it can rotate integrally with the stirring casing divided body, and rotates the stirring casing divided body while supplying the solidifying material. The agitation device is moved up and down, and the rotation control of the hydraulic motor is adjusted to the rotational speed of the hydraulic motor and the hydraulic motor, which are created in advance to correspond to each of the plurality of types of deposited earth and sand having different properties. The hydraulic pressure is controlled so that the hydraulic pressure is close to an upper limit value of an allowable range defined for the hydraulic motor and does not exceed the upper limit value based on a map or regression equation showing a correlation between the hydraulic oil pressure and the hydraulic oil pressure supplied. shall be.

According to the present invention, when the braking blade is located in sedimentary soil with high viscosity, the buried pile Since the agitation of the sediment deposited in the removed pile burial hole is promoted, the solidification material supplied from the solidification material supply section and the deposited soil are mixed efficiently and uniformly.
In addition, when the braking blade is located in muddy water with low viscosity, even if the rotational speeds of the first and second rotating blades match, the buried pile can be removed by moving the stirring device up and down. Since the agitation of the sediment deposited in the pile burial hole is promoted, the solidification material supplied from the solidification material supply section and the deposited soil are mixed efficiently and uniformly.
Therefore, by distributing the solidification material throughout the piled earth deposited in the pile burial hole, it is advantageous to improve the ground after the buried pile is removed to the same strength and rigidity as the surrounding ground.
In addition, the stirring device can be rotated and used with the excavation rig, making it possible to improve the ground without using the excavation rig and other heavy machinery as in the past, greatly reducing the time required for ground improvement and reducing construction costs. This is advantageous in reducing the
In addition, in this embodiment, the rotation control of the hydraulic motor that rotates the stirring casing segment is performed using the rotational speed of the hydraulic motor and the hydraulic pressure, which are created in advance in response to each of a plurality of types of accumulated sediment having different properties. Based on a map showing the correlation between the hydraulic oil supplied to the motor and the hydraulic pressure, the hydraulic pressure is controlled to be close to the upper limit of the allowable range set for the hydraulic motor and not to exceed the upper limit.
Therefore, the rotation speed of the first rotary vane and the second rotary vane can be maximized in accordance with the properties of the sediment to be stirred, without affecting the durability or life of the hydraulic motor. Not only can this method efficiently and uniformly mix the accumulated soil and sand, but it can also significantly shorten the time required for ground improvement, which is more advantageous in reducing construction costs.

FIG. 2 is an explanatory diagram of an excavation rig to which the stirring device of the first embodiment is applied. FIG. 2 is a partially cutaway perspective view of the stirring device according to the first embodiment. FIG. 2 is a longitudinal cross-sectional view of the stirring device according to the first embodiment. FIG. 2 is a perspective view from FIG. 1 with illustration of stirring blades omitted. FIG. 2 is a perspective view from FIG. 1 with illustration of a cylindrical stirring casing divided body not shown. (A) is an explanatory diagram showing a retracted position of the coupling member, and (B) is an explanatory diagram showing the coupling position of the coupling member. FIG. 2 is a block diagram showing the configuration of a rotation control device. (A)-(D) are diagrams of maps 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 device according to the first embodiment. It is a block diagram showing the composition of the rotation control device in a 2nd embodiment. It is a block diagram showing the composition of the rotation control device in a 3rd embodiment. FIG. 1 is an explanatory diagram of a conventionally used excavation device. FIG. 2 is an explanatory diagram of a method for removing buried piles using an excavator, in which (A) shows a state in which excavation of the ground with an excavation casing has started, and (B) shows a state in which excavation of the ground with an excavation casing has been completed. , (C) shows the state in which the casing has been pulled out of the ground and muddy water remains between the outer peripheral surface of the buried pile and the ground, and (D) shows the state in which the buried pile has been removed and accumulated soil and muddy water have accumulated in the pile burial hole. Indicates the condition.

(First embodiment)
A 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 diagram of an excavation rig 10 to which a stirring device according to the present embodiment is applied.
In the drilling equipment 10, the lowermost excavation casing division 34 of the casing 18 is replaced with a stirring casing division 34A that constitutes the stirring device 46 of the present invention, and the remaining upper end casing division 28 and The plurality of intermediate casing segments 30 and 32 are connected to 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 solidification material supply pipe 52 that supplies solidification material. The upper end casing segment 28A and the plurality of intermediate casing segments 30A and 32A are replaced.
Note that the external dimensions of the upper end casing segment 28A, the plurality of intermediate casing segments 30A, 32A, and the stirring casing segment 34A, and the structure for removably connecting these segments 28A, 30A, 32A, 34A, etc. are conventional. This is similar to the upper end casing division 28, the plurality of intermediate casing divisions 30 and 32, and the excavation casing division 34 used in the excavation rig 10.
Further, each of the divided bodies 28A, 30A, 32A, and 34A is made of steel.

The water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 are connected across the upper end casing division 28, the plurality of intermediate casing divisions 30A, 32A, and the stirring casing division 34A, and the upper end casing division 28A, a plurality of intermediate casing segments 30A and 32A, and a stirring casing segment 34A are connected to form a casing 18A.

The rotation drive unit 16A is configured to include a hydraulic motor 1604, as in FIG. 10, and is a part that rotationally drives the casing 18A. By combining the hexagonal cylinder part of the rotating shaft 1606 at the lower end of the part 16A and the hexagonal cylinder part of the connecting part 2802 at the upper end of the upper casing division 28, It is possible to employ various conventionally known connection and connection structures, such as placing the part over the small-diameter cylindrical part at the upper end of the upper end casing division body 28 and connecting it with bolts and nuts.
The rotation drive unit 16A connects the rotating shaft 1606 to the upper end casing segment 28A, the plurality of intermediate casing segments 30A and 32A, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 of the stirring casing segment 34A. Water, hydraulic oil, and solidifying material are supplied to the rotary drive unit 16A, which has a water pipe, a hydraulic oil pipe, and a solidifying material pipe (not shown).

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

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

As shown in FIGS. 2 to 4, the stirring device 46 includes a cylindrical stirring casing division 34A, a stirring blade 60, a second rotary blade 62, a bearing 64, and a switching section 66. It is configured.
The stirring casing segment 34A has a cylindrical shape with both ends in the axial direction open, and is disposed with the axial center facing in the vertical direction.
The upper end of the stirring casing division 34A is removably connected via a bolt to the portion of the casing 18A directly above the stirring casing division 34A, that is, the lower end of the lowest intermediate casing division 32A. ing. This connection structure is similar to the conventional connection structure between the intermediate casing segment 32 and the excavation casing segment 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 division 34A includes a water supply pipe 48, a hydraulic oil supply pipe 50, a solidification material supply pipe 52, a water injection hole 70 (see FIG. 1), and a solidification material injection hole 72. There is.
As shown in FIGS. 2 and 3, the water supply pipe 48 is connected to the outer peripheral surface of the stirring casing division 34A from the upper end of the stirring casing division 34A along the axial direction of the stirring casing division 34A. It extends to the cutter 68 for excavation 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. is provided.
Therefore, the water supplied from the water supply device 20 is injected from the water injection hole 70 to the lower part of the stirring casing segment 34A via the water supply hose 21, the water pipe of the rotation drive unit 16A, and the water supply pipe 48. .
In this embodiment, the water supply device 20, the water supply hose 21, the water conduit of the rotary drive unit 16A, and the water supply pipe 48 of the casing 18A constitute a water supply unit as claimed in the claims.

As shown in FIGS. 2 and 3, the hydraulic oil supply pipe 50 is connected to the outer peripheral surface of the stirring casing division 34A from the upper end of the stirring casing division 34A along the axial direction of the stirring casing division 34A. It extends to the middle part of the casing division body 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 section 66, which will be 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 pipe line 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 connected to the outer peripheral surface of the stirring casing division 34A from the upper end of the stirring casing division 34A along the axial direction of the stirring casing division 34A. It extends to a cutter 68 for excavation at the lower end of the casing divided body 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 segment 32A to which the stirring device 46 (stirring casing segment 34A) is connected, and the solidifying material supply pipe 52 is connected to 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 passed through the solidifying material hose 57, the solidifying material pipe line of the rotation drive unit 16A, and the solidifying material supply pipe 52 to the stirring casing segment from the solidifying material injection hole 72. It is injected below 34A.
In the present embodiment, the solidifying material supply device 56, the solidifying material hose 57, the solidifying material pipe line of the rotation drive section 16A, and the solidifying material supply pipe 52 of the casing 18A constitute the solidifying material supplying section of the claims. ing.

Note that in order to connect to the water pipe, hydraulic oil pipe, and solidifying material pipe of the rotational drive unit 16A, in the upper end casing division 28A, the water supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 are connected to the upper end casing division. It is provided inside the body 28A.
In addition, in order to connect to the water supply pipe 48, hydraulic oil supply pipe 50, and solidifying material supply pipe 52 of the stirring casing division 34A, at least the intermediate casing division 32A located directly above the stirring casing division 34A has no water. The lower portions of the supply pipe 48, the hydraulic oil supply pipe 50, and the solidifying material supply pipe 52 extend radially outward of the stirring casing division 34A, penetrate through the intermediate casing division 32A, and connect to the outer periphery of the intermediate casing division 32A. placed on the surface.

As shown in FIGS. 2 to 5, the stirring blade 60 is arranged at the axis of the stirring casing segment 34A.
The stirring blade 60 has a rotating shaft 74, a plurality of first rotating blades 76, and a plurality of brake blades 78.
The rotating shaft 74 is made of steel and is rotatably arranged on the axis of the stirring casing segment 34A.
The plurality of first rotating blades 76 are arranged radially outward of the rotating shaft 74 from circumferentially spaced locations at locations spaced apart in the longitudinal direction of the rotating shaft 74 from the upper and lower intermediate portions to the lower portion of the rotating shaft 74. It extends to
In this embodiment, the first rotating blades 76 are provided at two locations spaced apart in the longitudinal direction of the rotating shaft 74 and at two locations spaced apart by 180 degrees in the circumferential direction. A total of four sheets are provided.
Further, a cylindrical connection ring 80 is provided for each of the plurality of first rotary vanes 76 extending from the same location in the longitudinal direction of the rotary shaft 74 to connect the radially outer ends of the first rotary vanes 76. .
The vertical width of the connecting ring 80 is larger than the width of the first rotating blade 76, and the vertical ends of the connecting ring 80 protrude upward and downward from the vertical ends of the first rotating blade 76, respectively. ing.
The plurality of brake vanes 78 extend outward in the radial direction of the rotating shaft 74 from positions spaced apart in the circumferential direction of the upper part of the rotating shaft 74, respectively.
In this 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 thus a total of four braking blades 78 are provided.

The plurality of second rotary blades 62 are spaced apart in the circumferential direction of the inner circumferential surface of the stirring casing divided body 34A at locations spaced apart in the axial direction from the upper and lower intermediate portions to the lower part of the stirring casing divided body 34A. The plurality of second rotating blades 62 are provided at positions (phases) shifted from each other in the axial direction with respect to the first rotating blades 76. .
In this embodiment, the plurality of second rotary vanes 62 are arranged at three locations spaced apart in the axial direction and at two locations shifted in phase by 180° in the circumferential direction of the inner circumferential surface of the stirring casing segment 34A. A total of six second rotating blades 62 are provided.
The first rotary blade 76, the brake blade 78, and the second rotary blade 62 are each formed of a steel flat plate having a constant width and integral length, with the width direction facing the axial direction and the length direction facing the stirring direction. They are arranged in the radial direction of the casing divided body 34A, and are designed to efficiently mix the accumulated earth and sand 42 and the solidification material.
Further, the numbers of the first rotating blades 76, the braking blades 78, and the second rotating blades 62 are not limited to those in the embodiment, and can be set as appropriate.

The bearing 64 supports the rotating shaft 74 on the inner circumferential surface of the stirring casing segment 34A so that the rotating shaft 74 can rotate and cannot move in the axial direction.
In this embodiment, the bearing 64 rotatably supports the vertical ends of the connecting ring 80 and is immovable in the axial direction of the rotating shaft 74, thereby enabling the rotating shaft 74 to rotate and supporting the rotating shaft 74. It is supported immovably in the axial direction.
As shown in FIG. 3, the bearing 64 has a pair of lower locking pieces 82 and an upper locking piece 84 provided at a plurality of vertically spaced locations on the inner peripheral surface of the stirring casing divided body 34A. It is configured to be provided at multiple locations spaced apart in the direction.
The lower locking piece 82 includes a lower base portion 8202 that protrudes radially inward from the inner circumferential surface of the stirring casing division 34A, and a lower standing portion 8204 that stands upward from the tip of the lower base portion 8202.
The upper locking piece 84 includes an upper base portion 8402 that protrudes radially inward from the inner circumferential surface of the stirring casing segment 34A, and an upper standing portion 8404 that rises downward from the tip of the upper base portion 8402.
A lower base portion 8202 and an upper base portion 8402 are in movable contact with the lower end and upper end of the connecting ring 80, and a lower standing portion 8204 and an upper standing portion 8404 are provided on both sides of the connecting ring 80 in the thickness direction. , are movably in contact with the inner circumferential surface of the stirring casing segment 34A, and the connecting ring 80 is supported so as to be immovable in the axial direction and movable in the circumferential direction of the stirring casing segment 34A.

As shown in FIGS. 6(A) and 6(B), the switching unit 66 has a rotating shaft 74 on the inner peripheral surface of the stirring casing divided body 34A in a state where it can rotate with respect to the stirring casing divided body 34A, and This is to switch the rotating shaft 74 to a state where it can rotate integrally with the stirring casing segment 34A.
The switching section 66 includes an actuator 86 and an abutment member 88.
The actuator 86 is attached to the inner peripheral surface of the stirring casing division 34A.
The abutting member 88 is moved by the actuator 86 to a retracted position away from the first rotating blade 76 in the axial direction of the stirring casing segment 34A as shown in FIG. It moves between a contact position where it contacts the first rotating blade 76 in the circumferential direction of the axis and rotates the first rotating blade 76 integrally with the stirring casing segment 34A.
In this embodiment, the actuator 86 is a hydraulic cylinder, and the hydraulic cylinder includes a piston rod that expands and contracts with hydraulic oil supplied from the hydraulic oil supply pipe 50, and the abutting member 88 is constituted by the piston rod. .
The piston rod is always urged in the retracting direction by a spring built into the hydraulic cylinder, and when hydraulic oil is supplied, the piston rod protrudes against the biasing force.
Therefore, when hydraulic oil is not supplied, the piston rod retracts and the abutting member 88 is in the retracted position, and when hydraulic oil is supplied, the piston rod protrudes and the abutting member 88 is in the abutting position. To position.
Note that various conventionally known actuators such as an electric cylinder can be used as the actuator.

Next, the rotation control device 58 will be explained 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.
Tank 5802 stores hydraulic oil.
Hydraulic pump 5804 is an electric pump that supplies hydraulic oil sucked from tank 5802 to hydraulic motor 1604 via supply channel 5810 and direction switching valve 5806 provided in supply channel 5810.
The amount of hydraulic oil supplied to the hydraulic motor 1604 by the hydraulic pump 5804 is controlled by a rotation control unit 94, which will be described later, and the rotational speed of the hydraulic motor 1604 is controlled by controlling the amount of hydraulic oil supplied.

The direction switching valve 5806 is connected to the first and second supply/discharge ports 1604A and 1604B of the hydraulic motor 1604 via a normal rotation side supply flow path 5812 and a reverse rotation side supply flow path 5814.
The direction switching valve 5806 supplies hydraulic oil to the first supply/discharge port 1604A through the normal rotation side supply flow path 5812 under the control of the rotation control unit 94, thereby causing the hydraulic motor 1604 to rotate in the normal direction. A state in which the hydraulic oil discharged from the second supply/discharge port 1604B via the reverse side supply flow path 5814 is returned to the tank 5802 via the discharge flow path 5816, and a state in which the hydraulic oil is discharged from 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 hydraulic motor 1604, 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 be able to switch between the two states.
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 in the claims. .

The control device main body 90 is composed of a computer 90A, and the computer 90A has a CPU, ROM, RAM, hard disk device (or RAM disk device), mouse, keyboard, display device, input/output interface, etc. (all not shown). There is.
The ROM is composed of, for example, a flash memory, and stores control programs, etc., and the RAM provides a working area.
A hard disk device constitutes a storage unit that stores various information.
In this embodiment, a map storage section 92 is configured by a storage section.
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, as will be described later.
The mouse and keyboard accept operations by the operator.
The display device displays various 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.
The rotation control section 94 and the switching control section 96 are realized by the CPU executing the control program.

The map stored in the map storage unit 92 is the rotation speed of the stirring casing division 34A when the sediment 42 deposited in the pile burial hole 40 is stirred by the stirring casing division 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 data actually measured by stirring accumulated earth and sand 42 of various properties.
Specifically, the map shows the rotational speed N (rpm) of the hydraulic motor 1604 on the horizontal axis and the hydraulic pressure P of the hydraulic oil on the vertical axis, as shown in FIGS. 8(A) to 8(D). , the line diagram of each map shows a regression equation showing a correlation, and a plurality of them are provided depending on the properties of the deposited earth and sand 42.
For example, in the maps of FIGS. 8(A), (B), and (C), the slopes of the lines gradually become smaller in that order, indicating that the viscosity of the sediment 42 becomes lower in the above order. show. In such a case, the deposited earth and sand 42 is composed of earth and sand with a substantially uniform particle size, and the proportion of gravel contained therein is low.
Furthermore, in the map of FIG. 8(D), as the rotation speed N increases, the oil pressure P rises at a constant slope, and when the rotation speed N exceeds a certain level, the slope increases suddenly, and when the rotation speed N exceeds a certain level, the oil pressure P rises at a constant slope. Indicates that the slope is decreasing. In such a case, the accumulated earth and sand 42 often contains a relatively large amount of gravel (pebbles).
In this embodiment, a case has been described in which the properties of the accumulated sediment 42 are the viscosity of the accumulated sediment 42 and the ratio of gravel contained in the accumulated sediment 42. However, the properties of the accumulated sediment 42 are as follows: 42, that is, the rotation speed N of the hydraulic motor 1604 and the hydraulic pressure P of the hydraulic oil supplied to the hydraulic motor 1604. This includes various properties of the sediment 42.

The rotation control unit 94 controls the rotation of the hydraulic motor 1604 based on the above-mentioned map so that the oil pressure is close to the upper limit of the allowable range set for the hydraulic motor 1604 and does not exceed the upper limit.
Specifically, the rotation control unit 94 controls the rotation of the hydraulic motor 1604 by controlling the rotation of the hydraulic pump 5804 and controlling the flow rate of hydraulic oil supplied to the hydraulic motor 1604.

Further, the rotation control unit 94 selects a map based on the rotational 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 based on a map that is considered to correspond to the properties of the earth and sand in the ground where the pile burial hole 40 is formed. As time passes, if the relationship between the rotational speed N of the hydraulic motor 1604 and the detected oil pressure P deviates from the line diagram of the initially selected map, the relationship between the rotational speed N of the hydraulic motor 1604 and the detected oil pressure P Reselect another map that matches more accurately.
That is, if the properties of the accumulated sediment 42 are different from those initially expected, the rotation control unit 94 reselects a map closer to the actual accumulated sediment 42.

Further, when the amount of change per unit time in the oil pressure P detected by the oil pressure sensor 5808 exceeds a predetermined amount of change threshold, the rotation control unit 94 changes the rotation direction of the hydraulic motor 1604 from normal rotation to normal rotation. The rotation direction of the hydraulic motor 1604 is switched by switching the direction switching valve 5806 to reverse rotation or from reverse rotation to normal rotation.
This is because if the sediment 42 contains a mixture of areas with a lot of gravel and areas with a small amount of gravel, the amount of change in the oil pressure P per unit time will be abrupt in the area where there is a lot of gravel. This is to promote stirring of the accumulated earth and sand 42 containing a large amount of gravel by reversing the rotational direction of the stirring casing segment 34A from the previous direction.

The switching control unit 96 controls the above-described state in which the brake blade 78, the first rotary blade 76, and the second rotary blade 62 are rotated integrally (the brake blade 78, the first rotary blade 76, and the second rotary blade 62). A state in which the braking blade 78, the first rotating blade 76, and the second rotating blade 62 are rotated separately (a state in which the braking blade 78, the first rotating blade 76, and the second rotating blade 62 are rotated together) This is to control the switching of the switching section 66 to switch between a state in which co-rotation is not allowed.
Switching control of the switching unit 66 by the switching control unit 96 is performed by controlling the hydraulic oil supply device 54 based on the comparison result between the oil pressure detected by the oil pressure sensor 5808 and a predetermined oil pressure threshold, and supplying 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 section 96 will be described later.

Next, a method of using the stirring device 46 will be explained with reference to the flowchart of FIG. 9.
The excavation of the ground G around the buried pile 22 by the excavation device 10 and the removal of the buried pile 22 are the same as the procedures shown in FIGS. 11(A) to 11(D) described above, so a description thereof will be omitted.
As shown in FIG. 11(D), after the buried pile 22 is removed, sediment 42 with heavy specific gravity and high viscosity is deposited in the lower part of the pile burial hole 40, and fine grains are deposited in the upper part of the pile burial hole 40. A muddy water 44 with a light specific gravity and low viscosity, in which soil is suspended, is accumulated (step S10).
Here, as shown in FIG. 1, the existing rotary drive unit 16, upper end casing segment 28, multiple intermediate casing segments 30, 32, and stirring casing segment 34 are removed.
The rotary drive section 16A is provided with a water pipe, a hydraulic oil pipe, and a solidifying material pipe, an upper end casing segment 28A is provided with a water supply pipe 48, a hydraulic fluid supply pipe 50, a solidifying material supply pipe 52, and a plurality of Intermediate casing divisions 30A, 32A and stirring casing division 34A (stirring device 46) are replaced, and casing 18A is assembled (step S12).
In addition, the water supply device 20, the hydraulic oil supply device 54, and the solidifying material supply device 56 are connected to the water pipe line and the hydraulic oil pipe line of the rotary drive unit 16A via the water supply hose 21, the hydraulic oil hose 55, and the solidifying material hose 57, respectively. , are connected to the solidifying material pipe line, and the water supply pipe 48, hydraulic oil supply pipe 50, and solidifying material supply pipe 52 of the upper end casing division body 28A are connected to the water pipe, hydraulic oil pipe, and solidifying material pipe of the rotation drive unit 16A. Connect (step S14).

At this time, the hydraulic oil supply device 54 is inactive, hydraulic oil is not supplied to the actuator 86, the abutment member 88 is located at the retracted position, and the first rotating blade 76 is attached to the stirring casing segment 34A. In contrast, it is in a rotatable state (step S16). In other words, the braking blade 78, the first rotating blade 76, and the second rotating blade 62 do not rotate together.
Then, the rotation control device 58 starts operating, and the casing 18A is inserted into the pile burial hole 40 by letting out the wire 1212 of the crane 12 while rotating the casing 18A by the rotation drive 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 rotates through the muddy water 44 due to the weight of the casing 18A and the rotational force of the rotary drive unit 16A, and enters the accumulated earth and sand 42, and the water injected from the water injection hole 70 causes the stirring device 46 to rotate. It moves toward the bottom of the pile burial hole 40 while spreading the earth and sand 42.
Note that the rotation speed N of the hydraulic motor 1604 controlled by the rotation control device 58 is such that the stirring device 46 moves toward the bottom of the pile burial hole 40 while diffusing the accumulated earth and sand 42 with water injected from the water injection hole 70. It is sufficient if the rotational speed N is sufficient to do so, and is a preset value.
When the stirring device 46 penetrates the entire length of the sediment 42 and reaches the bottom of the pile embedding hole 40, the water supply by the water supply device 20 is stopped, and the wire 1212 of the crane 12 is turned off while the rotation of the casing 18A is maintained. The feeding is stopped (step S20).

Then, the worker operates the solidifying material supplying device 56 while maintaining the rotation of the casing 18A, thereby injecting the solidifying material from the solidifying material injection hole 72 to fill the pile embedding hole 40. 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 embedding hole 40.

Then, the rotation control unit 94 sets the rotation speed N of the hydraulic motor 1604 in advance based on the selected map corresponding to the properties of the soil in the pile burial hole 40, and the hydraulic motor 1604 rotates at the rotation speed N. The hydraulic pump 5804 is controlled as follows (step S24).
As a result, the plurality of second rotating blades 62 rotate integrally with the rotation of the casing 18A (the stirring casing divided body 34A), thereby stirring the accumulated earth and sand 42.
On the other hand, since the brake blade 78 is located in the highly viscous sediment 42, the brake blade 78 does not rotate integrally with the second rotary blade 62, but at a rotation speed that is slower than the rotation speed of the second rotary blade 62. Rotate.
Therefore, the first rotary blade 76 connected to the brake blade 78 via the rotation shaft 74 also rotates together with the brake blade 78 at a rotation speed slower than the rotation speed of the second rotary blade 62. In other words, the braking blade 78 brakes the rotation of the first rotary blade 76 .
That is, by stirring the accumulated earth and sand 42 by both the plurality of second rotating blades 62 having a high rotation speed and the plurality of first rotating blades 76 having a slow rotation speed, the stirring of the accumulated earth and sand 42 is promoted. The solidifying material injected from the solidifying material injection hole 72 and the accumulated earth and sand 42 are mixed efficiently and uniformly.
Then, while maintaining the rotation of the casing 18A and supplying the solidifying material, the crane 12 starts winding up the wire 1212, thereby moving the stirring device 46 upward, from the lower part of the pile burial hole 40 to the upper part. The deposited earth and sand 42 and the solidification material are mixed together toward the end (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 rotational speed N of the hydraulic motor 1604 based on the diagram of the currently selected map. It is determined whether 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 advances to the next step S32.

Next, the rotation control unit 94 determines whether the amount of change per unit time in the oil pressure P detected by the oil pressure sensor 5808 exceeds a predetermined amount of change threshold (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 advances to the next step S36.

As the agitation device 46 moves upward, the brake blade 78 eventually escapes from the highly viscous sediment 42 and enters the low viscosity muddy water 44, and the brake of the first rotary blade 76 by the brake blade 78 is released.
Here, the switching unit 66 is controlled by the switching control unit 96.
In a state where the brake blade 78 is braked by the accumulated dirt 42, the first rotating blade 76 and the brake blade 78 rotate following the accumulated sediment 42 that moves due to the rotation of the second rotating blade 62; 76 is braked by the brake blade 78, the load on 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 brake blade 78 moves from the accumulated earth and sand 42 into the muddy water 44, the braking of the first rotary blade 76 by the brake blade 78 becomes ineffective, and the second rotary blade 78 follows the moving accumulated earth and sand 42 by rotation of the second rotary blade 62, and the first rotary blade 76 moves. The first rotation blade 76 and the brake blade 78 rotate, but since the first rotation blade 76 is not braked by the brake blade 78, the first rotation blade 76 and the brake blade 78 rotate easily, so the casing 18A is rotated. The load on the hydraulic motor 1604 decreases, and the hydraulic pressure P detected by the hydraulic sensor 5808 becomes a hydraulic pressure P2 lower than the hydraulic pressure P1 when the brake blade 78 is braked by the accumulated earth and sand 42.
Therefore, a first threshold Pr1 (hydraulic threshold) is set smaller than the oil pressure P1 and larger than the oil pressure P2, and it is determined whether the oil pressure P is lower than the first threshold 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 rotating blade 76 is engaged with the contact member 88, so that the first rotating blade 76 rotates together with the casing 18A (the stirring casing divided body 34A), in other words, the braking blade 78 and Since the first rotating blade 76 and the second rotating blade 62 rotate together, the rotational speed of the first rotating blade 76 and the rotational speed of the second rotating blade 62 match.
Therefore, the sediment 42 near the first rotating blade 76 and the second rotating blade 62 moves following the rotation of the first rotating blade 76 and the second rotating blade 62, so the rotational speed of the first rotating blade 76 Agitation of the accumulated earth and sand 42 is suppressed compared to the case where the rotational speed is lower than the rotational speed of the second rotating blade 62.
Therefore, once the abutting member 88 is moved from the retracted position to the abutting position, the crane 12 alternately repeats hoisting and unwinding while maintaining the rotation of the casing 18A, and stirs while reciprocating the agitating device 46 up and down. By gradually moving the device 46 upward, stirring of the accumulated earth and sand 42 is promoted, and the accumulated earth and sand 42 and the solidification material are efficiently mixed (step S40).
That is, since the casing 18A is reciprocated up and down, the first rotating blade 76 and the second rotating blade 62 rotate in an area where the highly viscous accumulated sediment 42 and the low viscous muddy water 44 are mixed, thereby removing the accumulated sediment 42. This results in efficient stirring of the muddy water 44.

As described above, when it is detected in step S36 that the brake blade 78 has moved from the accumulated earth and sand 42 into the muddy water 44 and that the braking of the first rotary blade 76 by the brake blade 78 is no longer effective, the process proceeds to step S38. The braking blade 78, the first rotating blade 76, and the second rotating blade 62 were set to rotate together.
This is because when the stirring casing segment 34A moves near the boundary between the muddy water 44 and the accumulated earth and sand 42, the braking blade 78, the first rotating blade 76, and the second rotating blade 62 can rotate independently. It has been experimentally revealed that if left in this state, the rotation of the first rotary vane 76 and the second rotary vane 62 becomes unstable. This is because it has been experimentally found that when the two rotating blades 62 are switched to rotate together, the first rotating blade 76 and the second rotating blade 62 rotate stably.

Eventually, the agitation device 46 gets out of the piled earth and sand 42 and moves into the muddy water 44, in other words, the brake blade 78, the first rotary blade 76, and the second rotary blade 62 all come out of the piled up sand 42 and into the muddy water 44. Moving.
Here, the switching unit 66 is controlled by the switching control unit 96 again.
That is, when the brake blade 78, the first rotary blade 76, and the second rotary blade 62 all move into the muddy water 44, the brake blade 78, the first rotary blade 76, and the second rotary blade 62 move inside the muddy water 44, which has a low viscosity. Because of the rotation, the load on the hydraulic motor 1604 that rotates the casing 18A further decreases, and the hydraulic pressure P detected by the hydraulic sensor 5808 becomes a hydraulic pressure P3 lower than the above-mentioned hydraulic pressure P2.
Therefore, a second threshold Pr2 (hydraulic threshold) is set smaller than the oil pressure P2 and larger than the oil pressure P3, and it is determined whether the oil pressure P is lower than the second threshold Pr2 (step S42).
Note that the first threshold value Pr1 and the second threshold value Pr2 may be set after stirring the accumulated earth and sand 42 of various properties using the stirring device 46 and actually measuring the oil 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 causes the actuator 86 to move the contact member 88 from the contact position to the retreat position (step S44).
As a result, the engagement between the first rotating blade 76 and the contact member 88 is released, and the first rotating blade 76 becomes rotatable relative to the stirring casing segment 34A. In other words, the braking blade 78, the first rotating blade 76, and the second rotating 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 brake vanes 78 is not effective in the muddy water 44, and the first rotary vanes 76 and the brake vanes 78 rotate following the muddy water 44 that moves due to the rotation of the second rotary vanes 62 (casing 18A). However, the first rotary vane 76 and the second rotary vane 62 do not rotate together, but rotate independently of each other, so that the rotational speed of the first rotary vane 76 and the rotational speed of the second rotary vane 62 are different. will be different.
Therefore, while the first rotary vane 76 and the second rotary vane 62 move back and forth up and down, the first rotary vane 76 and the second rotary vane 62 rotate at mutually different rotational speeds, so the muddy water 44 and the solidifying material are efficiently agitated. By doing so, stirring of the muddy water 44 and the solidifying material is promoted, and therefore, the solidifying material injected from the solidifying material injection hole 72 and the muddy water 44 are mixed efficiently and uniformly.
It is determined whether the stirring device 46 has reached the upper part of the pile burial hole 40 and the mixed solidifying material and muddy water 44 have reached the upper end of the pile burial hole 40 (step S46), and if step S46 is negative, step S46 is repeated, and if step S46 is affirmative, the stirring device 46 is pulled out above the pile burial hole 40, and the series of operations ends (step S48).
As time passes, the solidifying material mixed with the sediment 42 solidifies in the lower part of the pile burying hole 40, and the muddy water 44 mixed with the solidifying material solidifies in the upper part of the pile burying hole 40. The ground at No. 40 will be 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 with a high rotation speed and the plurality of first rotary blades 76 with a low rotation speed Both promote stirring of the accumulated earth and sand 42 deposited in the pile burial hole 40 from which the buried pile 22 has been removed, so that the solidification material supplied from the solidification material supply unit and the accumulated earth and sand 42 are mixed efficiently and uniformly. .
In addition, the braking blade 78 is located in the muddy water 44 with low viscosity, and the first rotary blade 76 and the second rotary blade 62 are located in the sediment 42 with high viscosity. Even if the rotating blades 62 rotate together and the rotational speeds of the rotating blades 76 and 62 match, the amount of sediment that accumulates in the pile burial hole 40 from which the buried pile 22 has been removed by moving the stirring device 46 up and down. Since stirring of the earth and sand 42 is promoted, the solidification material supplied from the solidification material supply section and the deposited earth and sand 42 are mixed efficiently and uniformly.
Therefore, by distributing the solidification material throughout the piled earth and sand 42 deposited in the pile burying hole 40, it is advantageous to improve the ground after the buried pile 22 is removed to the same strength and rigidity as the surrounding ground G.
In addition, ground improvement can be carried out using the excavation device 10 that excavates the ground G in order to remove the buried pile 22, and heavy machinery different from the excavation device 10 as in the past is not required.
That is, by replacing the casing 18A of the excavation rig 10, the stirring device 46 can be rotated and used by the excavation rig 10, and ground improvement can be carried out without using other heavy machinery different from the excavation rig 10 as in the past. This can significantly shorten the time required for ground improvement, which is advantageous in reducing construction costs.

In addition, in this embodiment, the rotation control of the hydraulic motor 1604 that rotates the excavation casing divided body 34 is performed using a rotation control of the hydraulic motor 1604 that is created in advance to correspond to each of a plurality of types of accumulated earth and sand 42 having different properties. Based on a map showing the correlation between the speed N and the oil pressure of the hydraulic oil supplied to the hydraulic motor 1604, this is done so that the oil pressure is close to the upper limit of the allowable range defined for the hydraulic motor 1604 and does not exceed the upper limit.
Therefore, the rotational speeds of the first rotary vane 76 and the second rotary vane 62 can be made as high as possible in accordance with the properties of the accumulated sediment 42 to be stirred, without affecting the durability or life of the hydraulic motor 1604. .
Therefore, it goes without saying that the solidification material and the accumulated soil 42 can be mixed efficiently and uniformly, and the time required for ground improvement can be significantly shortened, which is more advantageous in terms of reducing construction costs.

Further, the map stored in the map storage unit 92 is created based on data actually measured by stirring the sediment 42 having various properties using the stirring device 46.
By actually measuring a large number of such data and creating more maps and storing them in the map storage unit 92, the rotation control of the hydraulic motor 1604 that rotates the excavation casing division body 34 can be controlled to This allows for more fine control in accordance with the properties of the sediment, which is more advantageous in maximizing the rotational speed of the first rotating blade 76 and the second rotating blade 62 in accordance with the properties of the sediment 42 to be stirred.
In addition, by actually measuring a large amount of data and creating a large number of maps, the brake blade 78, the first rotary blade 76, the second This is advantageous in designing the number and dimensions of the rotating blades 62.

Further, in this embodiment, the rotation control unit 94 selects a map based on the rotational 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 below to above the pile burial hole 40 while stirring the accumulated earth and sand 42, as time passes, the relationship between the rotational speed N of the hydraulic motor 1604 and the detected oil pressure P changes from the initially selected one. If the map deviates from the line diagram, a map that more accurately matches the relationship between the rotational speed N of the hydraulic motor 1604 and the detected oil pressure P is reselected, so it corresponds to the properties of the actual sediment. The rotational speed N of the hydraulic motor 1604 can be set to an appropriate value, and the solidification material and the sediment 42 can be mixed efficiently and uniformly without affecting the durability or life of the hydraulic motor 1604. This will be advantageous and will be even more advantageous in shortening the construction period for ground improvement work.

Furthermore, in this embodiment, the switching control section performs switching control of the switching section based on the comparison result between the oil pressure P detected by the oil pressure sensor and predetermined oil pressure threshold values Pr1 and Pr2. However, it may be done as follows.
That is, when the operator determines that the brake blade 78 has moved from the piled earth and sand 42 to the muddy water 44 or that the entire stirring device 46 has moved from the piled earth and sand 42 to the muddy water 44, the amount of winding of the wire 1212 by the crane 12, That is, based on the movement distance that the agitation device 46 has been lifted from the bottom, the operator operates the hydraulic oil supply device 54 to supply or release hydraulic oil, and operates the actuator 86 to remove the contact member. 88 may be moved from the retracted position to the contact position, or from the abutment position to the retracted position.
However, according to the present embodiment, switching control of the switching unit 66 by the switching control unit 96 can be performed automatically, eliminating the need for the operator to perform complicated operations, and improving work efficiency. It is advantageous.

Further, in this embodiment, the rotation control unit 94 controls the hydraulic motor 1604 when the amount of change per unit time in the oil pressure P detected by the oil pressure detection unit exceeds a predetermined change amount threshold. The direction of rotation is now reversed.
Therefore, for example, if the sediment 42 contains a mixture of parts where many gravels are distributed and parts where there are few gravels, the amount of change in the oil pressure P per unit time will be rapid in the parts where many gravels are distributed. By reversing the stirring casing segment 34A, the first rotary blade 76 and the second rotary blade 62 are reversed, so the movement of these rotary blades promotes agitation of the sediment 42 containing a large amount of gravel. This is more advantageous in efficiently and uniformly mixing the solidification material and the deposited earth and sand 42.

Further, the rotating shaft 74 may be rotatably supported by a plurality of stays protruding from the inner peripheral surface of the stirring casing segment 34A, but as in the present embodiment, a plurality of first rotating blades 76 By providing a connecting ring 80 that connects the radially outer ends of the casing 18A and a bearing 64 that supports the connecting ring 80 rotatably and immovably in the axial direction, it is possible to secure a large space inside the casing 18A and prevent the accumulation of This is advantageous in efficiently mixing the earth and sand 42 and the solidifying material and improving the ground efficiently.

Further, according to the present embodiment, the first rotating blade 76, the braking blade 78, and the second rotating blade 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 oriented toward the radial direction of the stirring casing divided body 34A, the first rotating blade 76, the brake blade 78, and the second rotating blade are arranged in the circumferential direction inside the stirring casing divided body 34A. 62 has a large area, which is advantageous in efficiently mixing the accumulated earth and sand 42 with the solidification material and efficiently improving the ground.

Further, according to the present embodiment, the switching portion 66 is moved between the actuator 86 attached to the inner circumferential surface of the stirring casing segment 34A, the retracted position away from the first rotating blade 76, and the retracted position away from the first rotary blade 76. The first rotary blade 76 is configured to include a contact member 88 that moves between a contact position that abuts the first rotary blade 76 and rotates the first rotary blade 76 integrally with the stirring casing segment 34A.
Therefore, regardless of the direction of rotation of the casing 18A, it is advantageous to ensure that the first rotating blade 76 rotates integrally with the stirring casing segment 34A, and the accumulated earth and sand 42 and the solidification material are mixed efficiently, and the soil This is advantageous in making improvements efficiently.

Further, according to the present embodiment, the stirring casing division 34A is a portion of the casing 18A directly above the excavation casing division 34 at the lower end of the casing 18A of the excavation rig 10 that is suspended and rotationally driven by the crane 12. Since it is detachably attached to the (intermediate casing divided body 32A), it is advantageous in simplifying the work of attaching and detaching the stirring device 46 to the excavation equipment 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 a case has been described in which this is done, instead of the map, it may be done based on a regression equation that shows the correlation between the rotational 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 rotational speed N of the hydraulic motor 1604 and the oil pressure P detected by the oil pressure sensor.

In addition, in this embodiment, the existing upper end casing segment 28, the plurality of intermediate casing segments 30, 32, the stirring casing segment 34, the water supply pipe 48, the hydraulic oil supply pipe 50, the solidifying material supply pipe 52 A case has been described in which the casing 18A is assembled by replacing the upper end casing segment 28A provided with the upper end casing segment 28A, the plurality of intermediate casing segments 30A and 32A, and the stirring casing segment 34A (stirring device 46).
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 division 28 and the plurality of intermediate casing divisions 30, 32. For example, there is no need to replace the existing upper end casing segment 28 and the plurality of intermediate casing segments 30, 32, which is advantageous in terms of reducing work time.

Furthermore, in the present embodiment, the water supply pipe 48 and the solidifying material supply pipe 52 are connected to each other in the upper end casing division 28A, the plurality of intermediate casing divisions 30A and 32A, and the stirring casing division 34A (stirring device 46). The case where the is provided independently has been explained.
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 pipe line of the rotary drive unit 16A and the solidifying material hose 57 are omitted, and there is a gap between the end of the water supply hose 21, the water supply device 20, and the solidifying material supply device 56. If a switching part is provided, and the switching part switches between the water supplied from the water supply device 20 and the solidification material supplied from the solidification 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 stirring casing segment 34A can be omitted, which is of course advantageous in simplifying the configuration of the stirring device 46 and reducing costs. Since the solidifying material supply pipes 52 of the remaining casing divided bodies 28A, 30A, and 32A, the solidifying material pipe line of the rotary drive unit 16A, and the solidifying material hose 57 can be omitted, the configuration of the excavating device 10 is simplified. It is also advantageous in terms of reducing costs.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG.
In the following embodiments, parts and members similar to those in the first embodiment are given the same reference numerals as in the first embodiment, and their explanations are omitted, and different parts will be mainly explained. 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 a predetermined oil pressure threshold value.
In contrast, in the second embodiment, as shown in FIG. 10, a proximity sensor 98 is provided on the outer peripheral surface of the stirring casing segment 34 to detect the presence or absence of an object, that is, to detect the presence or absence of accumulated earth and sand. Ta.
Then, based on the detection result of the proximity sensor 98, that is, when it is detected that the stirring casing segment 34 has moved from the piled earth and sand 42 to the muddy water 44, the switching control section 96 performs switching control of the switching section 66. This is what I did.
As the proximity sensor 98, various conventionally known sensors such as a capacitance sensor can be used.
The second embodiment also provides the same effects as the first embodiment.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. 11.
In the third embodiment, as shown in FIG. 11, a wire hoisting amount detection section 1220 that detects the amount of hoisting of the wire 1212 by the hoisting device of the crane 12 is provided.
Switching control of the switching unit 66 by the switching control unit 96 is performed based on a comparison result between the winding amount of the wire 1212 detected by the winding amount detection unit 1220 and a predetermined winding amount threshold. .
That is, the hoisting amount threshold is set in advance as the amount of hoisting sufficient to move the stirring casing segment 34 from the accumulated earth and sand 42 to the muddy water 44, and this hoisting amount threshold is, for example, The height is set by actually measuring or estimating the height from the bottom of the pile burial hole 40 at the boundary with the earth and sand 42 .
The third embodiment also provides the same effects as the first embodiment.

10 Excavation equipment 12 Crane 1212 Wire 1220 Wire hoisting amount detection section 16 Rotation drive section 1604 Hydraulic motor 18 Casing 20 Water supply device (water supply section)
21 Water supply hose (water supply part)
22 Buried pile 34 Excavated casing divided body 34A Stirring casing divided body 40 Pile burial hole 42 Accumulated earth and sand 44 Mud water 46 Stirring device 48 Water supply pipe (water supply part)
52 Solidifying material supply pipe (solidifying material supply section)
56 Solidifying material supply device (solidifying material supply section)
57 Solidifying material supply hose (solidifying material supply section)
58 Rotation control device 5804 Hydraulic pump 5808 Hydraulic sensor (hydraulic detection unit)
60 Stirring blade 62 Second rotating blade 64 Bearing 66 Switching unit 74 Rotating shaft 76 First rotating blade 78 Braking blade 80 Connection ring 86 Actuator 88 Contact member 90 Control device main body 90A Computer 92 Map storage unit 94 Rotation control unit 96 Switching control Section 98 Proximity sensor

Claims (14)

This is a stirring device that is used to replace the excavation casing division at the lower end of the casing of a drilling equipment that is suspended by a crane and rotationally driven by a hydraulic motor, and that stirs the solidified material and the accumulated soil and mud that accumulates in the pile burial hole. There it is,
The agitation device is a cylindrical agitation casing segment that is arranged with its axis directed in the vertical direction, is removable from a portion of the casing directly above the excavation casing segment, and has a cutter for excavation on the outer periphery of the lower end. a stirring blade disposed inside the stirring casing division; a water supply section that supplies water to the lower end of the stirring casing division; and a water supply section that supplies the solidifying material to the lower end of the stirring casing division. comprising a solidifying material supply section for supplying the solidifying material, and a rotation control section for controlling the rotation of the hydraulic motor,
The stirring blade includes a rotating shaft extending along the axial center and arranged to be immovable in the axial direction of the stirring casing segment and rotatable on the axial center, and a rotating shaft extending between the upper and lower intermediate points of the rotating shaft. a plurality of first rotary vanes extending outward in the radial direction of the rotary shaft from circumferentially spaced points at locations spaced apart in the longitudinal direction of the rotary shaft in the lower part; a plurality of brake blades extending outward in the radial direction of the rotating shaft from locations spaced apart in the circumferential direction, and spaced apart in the axial direction from the upper and lower intermediate portions of the stirring casing division body to the lower part; A plurality of second rotary blades extending radially inward of the stirring casing divided body are arranged at circumferentially spaced locations on the inner circumferential surface of the stirring casing divided body at locations relative to the first rotary blade. provided at a position shifted in the axial direction ,
The rotation control unit is configured to set the oil pressure to the hydraulic motor based on a map or a regression equation showing a correlation between the rotational speed of the hydraulic motor and the oil pressure of hydraulic oil supplied to the hydraulic motor. controlling the rotation of the hydraulic motor so as to be close to an upper limit of an allowable range and not to exceed the upper limit;
The map or the regression equation is created in advance in correspondence to each of the plurality of types of deposited sediment that have mutually different properties.
A stirring device characterized by: A stirring device that is replaced by a divided excavation casing at the lower end of a drilling rig that is suspended by a crane and rotationally driven by a hydraulic motor, and that stirs accumulated soil and muddy water deposited in a pile burial hole and solidified material,
The stirring device includes:
A cylindrical stirring casing segment arranged with its axis directed in the vertical direction;
a stirring blade disposed inside the stirring casing division;
a solidifying material supply unit that supplies the solidifying material to the lower end of the stirring casing division;
a rotation control section that controls rotation of the hydraulic motor;
The stirring blade is
a rotating shaft extending along the axis;
a plurality of first rotating blades extending radially outward of the rotating shaft at intervals in the circumferential direction;
a plurality of brake vanes provided above the plurality of first rotary vanes on the rotary shaft and extending radially outward of the rotary shaft at intervals in the circumferential direction;
The stirring casing divided body has a plurality of second rotating blades extending radially inward of the stirring casing divided body at intervals in the circumferential direction of the inner peripheral surface,
The plurality of second rotating blades are provided shifted in position in the axial direction with respect to the plurality of first rotating blades,
The rotation control unit is configured to adjust the oil pressure within a permissible range defined for the hydraulic motor based on a map or regression equation showing a correlation between the rotational speed of the hydraulic motor and the oil pressure of hydraulic oil supplied to the hydraulic motor. controlling the rotation of the hydraulic motor so as to be close to an upper limit value of and not to exceed the upper limit value;
The map or the regression equation is created in advance in correspondence to each of the plurality of types of deposited sediment that have mutually different properties.
A stirring device characterized by: comprising a switching section, the switching section switching between a state in which the rotating shaft is rotatable relative to the stirring casing segment, and a state in which the rotating shaft is rotatable integrally with the stirring casing segment;
The stirring device according to claim 1 or 2, characterized in that: comprising an oil pressure detection unit that detects oil pressure of hydraulic oil supplied to the hydraulic motor,
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 any one of claims 1 to 3, characterized in that: comprising a switching control section that performs switching control of the switching section,
The switching control of the switching unit by the switching control unit is performed based on a comparison result between the oil pressure detected by the oil pressure detection unit and a predetermined oil pressure threshold;
The stirring device according to claim 3 , characterized in that: comprising a switching control section that performs switching control of the switching section,
Providing a proximity sensor in the stirring casing segment,
Switching control of the switching unit by the switching control unit is performed based on a detection result of the proximity sensor,
The stirring device according to claim 3 , characterized in that: The stirring casing segment is suspended from the crane via a wire,
a winding amount detection unit for detecting the winding amount of the wire;
comprising a switching control section that performs switching control of the switching section,
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 detection unit, a predetermined winding amount , and a threshold value.
The stirring device according to claim 3 , characterized in that: The rotation control unit reverses the rotation direction of the hydraulic motor when the amount of change per unit time in the oil pressure detected by the oil pressure detection unit exceeds a predetermined change amount threshold.
The stirring device according to claim 4 , characterized in that: The switching section includes an actuator attached to an inner circumferential surface of the stirring casing segment, a retracted position separated from the first rotary blade in the axial direction of the stirring casing segment by the actuator, and an abutting member that abuts the first rotary vane in the circumferential direction of the shaft center and moves between a contact position that rotates the first rotary vane together with the stirring casing segment; There is,
The stirring device according to claim 3 , characterized in that: A cylindrical stirring casing division body arranged with its axis directed in the vertical direction and open at both ends in the axial direction, a stirring blade arranged inside the stirring casing division body, and the stirring casing division body A stirring device comprising a solidifying material supply section that supplies the solidifying material to the inside of the body,
The stirring blade includes a rotating shaft extending along the axial center and arranged to be immovable in the axial direction of the stirring casing segment and rotatable on the axial center, and a rotating shaft extending between the upper and lower intermediate points of the rotating shaft. a plurality of first rotary vanes extending outward in the radial direction of the rotary shaft from circumferentially spaced points at locations spaced apart in the longitudinal direction of the rotary shaft in the lower part; a plurality of brake vanes extending radially outward of the rotating shaft from circumferentially spaced locations;
The stirring casing divisions are placed at intervals in the circumferential direction of the inner circumferential surface of the stirring casing division body at locations spaced apart in the axial direction from the upper and lower intermediate parts to the lower part of the stirring casing division body. A plurality of second rotary vanes extending inward in the radial direction of the body are provided with positions shifted in the axial direction with respect to the first rotary vanes ,
A hydraulic motor is provided for rotating the stirring casing segment,
A map or regression equation showing the correlation between the rotational speed of the hydraulic motor and the hydraulic pressure of the hydraulic oil supplied to the hydraulic motor, which is created in advance in correspondence with each of the plurality of types of deposited earth and sand having different properties. Based on this , the rotation of the hydraulic motor is controlled so that the hydraulic pressure is near an upper limit value of an allowable range defined for the hydraulic motor and does not exceed the upper limit value , and the stirring casing segment is rotated.
A ground improvement method for pile burial holes characterized by the following. A cylindrical stirring casing division body arranged with its axis directed in the vertical direction and open at both ends in the axial direction, a stirring blade arranged inside the stirring casing division body, and the stirring casing division body A stirring device comprising a solidifying material supply section that supplies the solidifying material to the inside of the body,
The stirring blade is
a rotating shaft extending along the axis;
a plurality of first rotating blades extending radially outward of the rotating shaft at intervals in the circumferential direction;
a plurality of brake vanes provided above the plurality of first rotary vanes on the rotary shaft and extending radially outward of the rotary shaft at intervals in the circumferential direction;
The stirring casing divided body has a plurality of second rotating blades extending radially inward of the stirring casing divided body at intervals in the circumferential direction of the inner peripheral surface,
The plurality of second rotating blades are provided shifted in position in the axial direction with respect to the plurality of first rotating blades,
A hydraulic motor is provided for rotating the stirring casing segment,
A map or regression formula showing the correlation between the rotational speed of the hydraulic motor and the hydraulic pressure of the hydraulic oil supplied to the hydraulic motor, which is created in advance for each of the plurality of types of deposited earth and sand having different properties. Based on this, the rotation of the hydraulic motor is controlled so that the hydraulic pressure is near an upper limit value of an allowable range defined for the hydraulic motor and does not exceed the upper limit value, and the stirring casing segment is rotated.
A ground improvement method for pile burial holes characterized by. Furthermore, a switching part is provided for switching between a state in which the rotating shaft is rotatable relative to the stirring casing divided body and a state in which the rotating shaft is rotatable integrally with the stirring casing divided body. The ground improvement method according to claim 10 or 11 for pile burying holes.. When the stirring device is located in muddy water with low viscosity, the switching unit switches the rotating shaft to a state where it can rotate with respect to the stirring casing divided body, and divides the stirring casing while supplying the solidifying material. The body is rotated and the stirring device is moved up and down.
13. The method for improving ground in a pile burial hole according to claim 12 . The stirring casing division is removably attached to a portion of the casing immediately above the excavation casing division at the lower end of the casing of an excavation rig that is suspended and rotationally driven by a crane.
14. The ground improvement method for pile burial holes according to any one of claims 10 to 13 .

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