JP3560359B2 - Ground improvement equipment - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a ground improvement device used for improving a ground by injecting a ground improvement material into the ground.
[0002]
[Prior art]
As a ground improvement method to improve a soft ground to make it a solid ground, excavating the ground and mixing it with earth and sand by stirring it while injecting a soil improvement material such as cement slurry into the drilled hole, this hardens It has been made to improve the ground strongly.
[0003]
As an apparatus for performing the above method, there is an apparatus disclosed in Japanese Patent Application Laid-Open No. 2-140321. This device connects the injection shaft with stirring blades at the lower part of the auger screw, and selectively improves the ground from the discharge port opened at the lower end and upper side of the injection shaft through the passage in the shaft of the auger screw and the injection shaft. The material is discharged, and the discharge port is selected by a switching device built in a position below the shaft portion of the auger screw, and the switching operation is performed by moving the injection shaft up and down. I have.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional device, since the fluid switching device is provided in the lower portion of the shaft portion of the auger screw, the diameter of the shaft portion incorporating the switching device increases, and the weight increases accordingly, and During the work, the switching device is located underground, so there is a risk of malfunction due to intrusion of earth and sand and water, and it is not possible to confirm whether the switching operation was performed normally, and it is lacking reliability. There was a problem.
[0005]
In view of the above, it is an object of the present invention to provide a highly reliable soil improvement device which does not cause an increase in the diameter of a shaft portion, can easily confirm switching, and injects a soil improvement material. It is an object of the present invention to provide a ground improvement device capable of grasping the amount in real time.
[0006]
[Means for Solving the Problems]
The ground improvement device according to claim 1 of the present invention which solves the problems of the above-mentioned conventional technology ,
It is connected to a driving unit that moves up and down along the leader mast, and has a stirring blade that protrudes in a radial direction on an outer periphery of a predetermined range at a lower end thereof, and a screw blade is screwed above the stirring blade. A stirring shaft,
A first fluid passage provided inside the stirring shaft and communicating with a first discharge port opened at a lower end of the stirring shaft;
A second fluid passage which is provided inside the stirring shaft and communicates with a second discharge port opened above the stirring blade on a side surface of the stirring shaft;
A first supply pipe communicating with the first fluid passage via a double swivel device above the stirring shaft, and a second supply pipe communicating with the second fluid passage;
A switching device having a valve and a branch pipe interposed in a piping system of the first supply pipe and the second supply pipe;
An air supply source for supplying air via the switching device;
A plant for supplying cement slurry or water via the switching device,
With
The switching device,
When excavating a non-improved portion of the ground surface downward, water or air is supplied through the first supply pipe and the first fluid passage and discharged from the first discharge port,
When the excavation of the non-improved portion is finished, so as not to discharge fluid from the first discharge port and the second discharge port,
When digging downward from the bottom of the ground improvement section toward the bottom from a position at an appropriate depth, cement slurry is supplied through the first supply pipe and the first fluid passage to supply the cement slurry from the first discharge port. Discharge
When pulling up the stirring shaft from the position of the appropriate depth toward the non-improved portion, a cement slurry is supplied through the second supply pipe and the second fluid passage to be discharged from the second discharge port. As if
The opening and closing of each of the valves is operated.
The ground improvement device according to claim 2 of the present invention is further characterized by further comprising a flow meter connected to the first supply pipe and the second supply pipe on the downstream side of the switching device.
[0007]
[Action]
Since the surface portion of the ground usually has a relatively hard layer or does not require ground improvement in many cases, the ground of the surface non-improved portion is excavated while discharging water (or air) from the first discharge port. Water facilitates the excavation of hard ground, and air contributes to the efficiency of screw removal. The supply of these fluids is selected according to the properties of the ground, and is performed by operating a switching device.
[0008]
When the excavation of the surface non-improved portion is exceeded, the excavation proceeds by stopping the discharge of the fluid at all by switching the switching device from the first discharge port or the second discharge port. This is to prevent the improved portion, which is a soft formation, from being further softened by the fluid. The excavated earth and sand is discharged to the ground by screw blades.
[0009]
When it reaches the lower part of the ground improvement part, the stirring shaft is pulled up to the upper end of the appropriate depth (doubling part) as it is, and then the switching device is switched to discharge cement slurry or the like (coagulable chemical solution) from the first discharge port. Re-excavation is performed to the bottom of the improved part while stirring and mixing with the earth and sand by the stirring blade. When the bottom of the improved part is reached, the switching device is switched to stop the discharge of the fluid (chemical solution) from the first discharge port. The stirring shaft is pulled up until the second discharge port is located at the upper end. Thereafter, the discharge from the second discharge port is performed again, and the work is performed up to the surface non-improved portion while stirring and mixing with the earth and sand. When the non-improved surface layer is reached, the discharge port from the second discharge port is stopped, and the stirring shaft is pulled out to the ground.
[0010]
【Example】
Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.
FIG. 1 is a side view showing an example of the entire configuration of a ground improvement device according to the present invention. FIG. 3 shows a cross section of the stirring shaft 1. The stirring shaft 1 is a leader mast installed on a base machine 2. 3 is supported so as to be able to move up and down along a guide rail 4 on the side surface thereof, is connected to an output shaft of a drive unit 7 on which a motor 5, a speed reducer 6 and the like are mounted, and is hung down. Being vertically supported.
[0011]
The drive unit 7 guides the wire 10 wound around the sheave 9 at the upper part thereof to a winch (not shown) on the base machine 2 via the sheave 11 at the upper end of the leader mast 3, and raises and lowers the winch. The drive unit 7 moves up and down, and the stirring shaft 1 moves up and down.
[0012]
The stirring shaft 1 is provided with a plurality of stages of stirring blades 12, 12,... Projecting in the radial direction on the outer periphery of a predetermined range at the lower end of the shaft portion 1A, and is provided above a region where the stirring blades 12, 12,. A screw blade 13 is screwed around the shaft portion 1A.
[0013]
Two fluid passages (a first fluid passage 14 and a second fluid passage 15) are provided inside the shaft portion 1A, and the first fluid passage 14 is located at the shaft center and penetrates the upper and lower ends of the shaft portion 1A. The lower end is communicated with a first discharge port 16 that opens at the lower end of the shaft portion 1A. The second fluid passage 15 is located around the first fluid passage 14, and a lower portion of the second fluid passage 15 is opened at a side surface above a range where the stirring blades 12 are provided. 17.
[0014]
The upper portions of the first and second fluid passages 14 and 15 are connected to a double swivel device 18. In the double swivel device 18, as shown in a sectional view in FIG. 4, a first supply pipe 20 is rotatably connected to an upper end member 1B of a shaft portion 1A via seals 19, 19. The one supply pipe 20 and the first fluid passage 14 are always in communication.
[0015]
An outer casing 21 is rotatably fitted to the outer periphery of the upper part of the shaft 1A via seals 22 and 22, and the outer casing 21 is opened in the outer casing 21 on the outer peripheral surface of the shaft 1A. The opening 23 of the two-fluid passage 15 is exposed, and the second supply pipe 24 connected to the outer casing 21 and the second fluid passage 15 are always in a communication state.
[0016]
In the illustrated embodiment, the first supply pipe 20 is connected to a compressor 25 as an air supply source, and the second supply pipe 24 is connected to a plant 26 as a supply source of cement slurry (or water). A switching device 27 is interposed in the piping system of these supply pipes. In FIG. 4, reference numeral 28 denotes a detent member for fixing the connection pipe 20a of the cover / first supply pipe 20 of the double swivel device 18 with bolts 20b.
[0017]
The switching device 27 includes a valve 29 that opens and closes the first supply pipe 20, a valve 30 that opens and closes the second supply pipe 24, and a branch upstream of the valve 30 of the second supply pipe 24. And a valve 32 for opening and closing the branch pipe 31 that merges downstream of the valve 29. The valves 29, 30, and 32 are electromagnetically operated valves. Note that these valves may be configured as one unit.
[0018]
In the illustrated embodiment, the downstream side of the junction of the first supply pipe 20 and the downstream side of the valve 30 of the second supply pipe 24 are located so that the injection amount of the cement slurry can be grasped in real time. Flow meters 33 and 34 are connected, and these valves 29, 30 and 32 and the flow meters 33 and 34 constitute a control unit 35.
[0019]
Next, the operation of the embodiment will be described.
Since the surface portion of the ground usually has a relatively hard layer or it is not necessary to improve the ground in many cases, the valve 29 or 32 of the switching device 27 is opened, the valve 30 is closed, and the lower end of the stirring shaft 1 is closed. While discharging water or air from the first discharge port 16, the ground of the surface non-improved portion A is excavated as shown in FIG. It should be noted that discharging water facilitates excavation of hard ground, and supplying air has an effect in increasing the soil discharging efficiency of the screw blade 13. The type and availability of these fluids are selected according to the properties of the ground, and are performed by operating the switching device 27.
[0020]
When the excavation of the surface layer non-improved portion A is exceeded, the excavation proceeds by stopping the discharge of any fluid from the first discharge port 16 or the second discharge port 17 by switching of the switching device 27 (FIG. 5B). This is to prevent the improved portion B, which is a soft formation, from being further softened by the fluid. The excavated earth and sand is discharged to the ground by the screw blade 13.
[0021]
When the stirring shaft 1 reaches the bottom of the ground improvement part B as shown in FIG. 5 (C), the stirring shaft 1 is moved to the upper end position of an appropriate depth (a region where the shallow and deep excavation is alternately performed and is referred to as a doubling part W). Then, the valve 32 of the switching device 27 is opened, the cement slurry is discharged from the first discharge port 16 through the first fluid passage 14, and the agitating blades 12, 12,. Re-digging to the bottom (FIG. 5 (D)), and when reaching the bottom of the improvement part B, the valve 32 of the switching device 27 is closed to stop the discharge of the cement slurry from the first discharge port 16 and the upper end position of the doubling part W Then, the stirring shaft 1 is pulled up until the second discharge port 17 is positioned (FIG. 5E).
[0022]
Thereafter, the cement slurry is discharged from the second discharge port 17 again, and the work is performed up to the surface layer non-improved portion A while stirring and mixing with the soil (FIG. 5 (F)). When the surface layer non-improved portion A is reached, the discharge of the cement slurry from the second discharge port 17 is stopped, the stirring shaft 1 is pulled out to the ground, and the operation is completed (FIG. 5 (G)).
[0023]
The discharge amount of the cement slurry in the above operation is detected by the flow meters 33 and 34, and when the amount is different from the planned amount, the supply amount is adjusted.
[0024]
【The invention's effect】
As described above, according to the present invention, the switching device for switching the fluid to be supplied to the ground through two fluid passages in the stirring shaft is provided at a position above the stirring shaft and not directly related to the stirring shaft. , The switching can be easily confirmed, the reliability of the operation can be improved, and the diameter of the stirring shaft does not increase, so that the weight can be prevented from increasing.
Furthermore, if the ground of the surface unimproved portion is excavated while discharging water (or air) from the first discharge port , the water facilitates excavation of the hard ground, and the air contributes to enhancing the soil removal efficiency by the screw. .
[0025]
Further, if a flow meter is provided in the fluid supply system as in claim 2, the injection amount of the chemical such as cement slurry can be grasped in real time, and the accuracy of the pile can be improved.
[0026]
If the switching device is attached to the drive unit as in the illustrated embodiment, it is effective in reducing the time lag between switching and discharge.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an overall configuration example of a ground improvement device according to the present invention.
FIG. 2 is an enlarged view of a driving unit in FIG.
FIG. 3 is a partially cutaway sectional view showing a stirring shaft and a fluid supply system according to the present invention.
FIG. 4 is an enlarged sectional view of the double swivel device in FIG. 3;
5 (A) to 5 (G) are explanatory views showing aspects during stirring and mixing.
[Explanation of symbols]
Reference Signs List 1 stirring shaft 3 leader mast 7 drive unit 12 stirring blade 13 screw blade 14 first fluid passage 15 second fluid passage 16 first discharge port 17 second discharge port 18 double swivel device 20 first supply pipe 21 outer casing 23 Opening 24 Second supply pipe 25 Air supply source (compressor)
26 Plant 27 Switching device 29, 30, 32 Valve 33, 34 Flow meter 35 Control unit

Claims (2)

It is connected to a driving unit that moves up and down along the leader mast and hangs down. A stirring shaft,
A first fluid passage provided inside the stirring shaft and communicating with a first discharge port opened at a lower end of the stirring shaft;
A second fluid passage that is provided inside the stirring shaft and communicates with a second discharge port that opens on the side of the stirring shaft above the stirring blade;
A first supply pipe communicating with the first fluid passage via a double swivel device above the stirring shaft, and a second supply pipe communicating with the second fluid passage;
A switching device having a valve and a branch pipe interposed in a piping system of the first supply pipe and the second supply pipe;
An air supply source for supplying air via the switching device;
A plant for supplying cement slurry or water via the switching device,
With
The switching device,
When excavating a non-improved portion of the ground surface downward, water or air is supplied through the first supply pipe and the first fluid passage and discharged from the first discharge port,
When the excavation of the non-improved portion is finished, so as not to discharge fluid from the first discharge port and the second discharge port,
When digging downward from the bottom of the ground improvement section toward the bottom from a position at an appropriate depth, cement slurry is supplied through the first supply pipe and the first fluid passage, and the cement slurry is supplied from the first discharge port. Discharge
When pulling up the stirring shaft from the position of the appropriate depth toward the non-improved portion, a cement slurry is supplied through the second supply pipe and the second fluid passage and discharged from the second discharge port. As if
A ground improvement device wherein opening and closing of the valves are respectively operated. The ground improvement device according to claim 1, further comprising a flow meter connected to each of the first supply pipe and the second supply pipe downstream of the switching device.

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