JP3072411B2 - Ground improvement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil improvement apparatus for excavating soft ground, injecting a stabilizer into the excavated soil, and mixing and stirring the soft ground to improve the soft ground.

[0002]

2. Description of the Related Art Conventionally, various soil improvement devices for excavating soft ground, injecting stabilizing material into the excavated soil, and mixing and agitating the soft ground to improve the soft ground have been researched and developed. Belongs to the public, and there are already some examples. For example, in the conventional ground improvement apparatus shown in FIGS. 7A and 7B, a stirring and excavating shaft b is connected to a lower end of a rotary drive shaft a in series by a joint or the like. An excavating cutter w for excavating soft ground is provided at the lower end of the agitating excavation shaft b, and agitating blades c are mounted above and below the agitating excavation shaft in three stages.
The rotary drive shaft a and the stirring and excavating shaft b are each formed in an inner and outer double pipe structure, an upper injection hole e is opened at the lower end of the inner pipe d, and a lower injection hole g is opened at the lower end of the outer pipe f. ing. Above the inner pipe d and the outer pipe f, a hose h for the inner pipe and a hose i for the outer pipe are connected by swivel joints j and k, respectively, as shown in FIG. 7A. These two hoses h and i are switching valves. The other end of the hose n is connected to a stabilizer injection machine p via m.

The above-mentioned ground improvement device is used as follows. First, the rotary drive shaft a is rotated to excavate to a predetermined depth. At the time when the excavation reaches the upper end of the solidification part, the switching valve m is switched to the outer pipe hose i side to improve the solidification part, the stabilizer is fed by the stabilizer injection machine p, and the lower injection hole is formed. The excavation and stirring and mixing by rotation drive are advanced to the planned depth while injecting (penetrating and discharging) the stabilizer from g. When the excavation reaches the planned depth, the switching valve m is switched to the side of the inner pipe hose h, and the stabilizer is injected (withdrawn and discharged) from the upper injection hole e, and the rotary drive shaft a is rooted while stirring and mixing. Pull up to the top of the hardened part. Further, if necessary, the above-described intrusion discharge and pull-out discharge are repeated several times to form a rooted portion where the stabilizer is dense. Thereafter, an improved soil column is formed by performing stirring and mixing in a process of pulling the rotary drive shaft a to the ground while injecting (pulling and discharging) the stabilizer from the upper injection hole e, thereby forming such an improved soil column in a planar manner. To form an improved ground.

[0004]

In the above-mentioned conventional ground improvement apparatus, two hoses h and i are connected to the inner pipe d and the outer pipe f using the swivel joints j and k, respectively, and the upper injection is performed. Since the supply of the stabilizer to the hole e and the lower injection hole g is switched by operating the switching valve m, the structure of the device is complicated. That is, two hoses h and i for injecting the stabilizer into one shaft are required, and accordingly, two swivel joints j and k for connecting the hoses h and i to the rotary drive shaft a. And the like are also required, and the work of installing these is also cumbersome and costly. In addition, the two swivel joints j, k, if not carefully maintained,
Clogging phenomena due to internal leakage of the stabilizer and the like due to wear and damage of the rotary sliding portion are likely to occur, and maintenance is troublesome.

Accordingly, an object of the present invention is to provide a single shaft and a single swivel joint for one shaft, which has a simple structure, facilitates facility work, and has an earth pressure accompanying rotation of the drive shaft. To provide a ground improvement device provided with a switching valve that can freely switch the flow path to the stabilizer injection hole by utilizing the operation of (i.e., changing the rotation direction of the drive shaft in the forward and reverse directions). It is in.

[0006]

According to another aspect of the present invention, there is provided a ground improvement apparatus according to the present invention, wherein a lower end of a drive shaft 4 rotatably supported in a vertically downward arrangement. The upper end of the stirring and excavating shaft 5 is connected in series to the portion, and the stirring and excavating shaft 5 is provided with a cutting cutter 6 for excavating soft ground at the lower end, and a plurality of stirring blades 7 are provided above the lower portion. A tip injection hole 8 for injecting and discharging the stabilizer is provided at the tip, and an upper injection hole 9 for extracting and discharging the stabilizer is provided at the upper portion, and the soft ground is excavated to be stable in the excavated soil in the original position. In a soil improvement apparatus for improving the soft ground by injecting wood and stirring and mixing with the soil, the valve 1 is switched to a position near the upper end of the stirring and excavating shaft 5.
0 is provided, and the switching valve 10
A valve body 12 having at least three of a flow path communicating with a stabilizer supply hose, a flow path communicating with the upper injection hole, and a communication path communicating with the tip injection hole 8 has a horizontal center line. The conversion blade 15 is attached to the shaft 14 protruding along the center line of the valve body 12 so as to be rotatable, and the conversion blade 15 is attached substantially downward.
Two switching bars 17a and 17b for rotating and stopping the valve body 12 are protruded from a ring body 16 rotating along the outer periphery of the stirring and excavating shaft 5, and the rotation range of the ring body 16 is controlled. A positioning piece 18 for regulating protrudes from the ring body 16, and stoppers 19a and 19b are fixedly provided on the outer peripheral surface of the stirring and excavating shaft at two positions where the positioning piece 18 abuts at a predetermined rotation angle. It is characterized by the following.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of the ground improvement device. The drive shafts 4 and 4 of two axes (single axes or three or more axes) which are connected at their upper ends to a rotation drive unit (processor main body) 1 and rotatably supported in a vertically downward arrangement are supported. The upper end of the stirring and excavating shaft 5 is connected to the lower end in series. The stirring excavation shaft 5
Is provided at its lower end with a digging cutter 6 for digging soft ground, and above it, agitating blades 7 protruding in the radial direction are provided in two vertical stages (however, the number of stages is not limited). . A tip injection hole 8 for penetrating and discharging the stabilizer is provided at a tip of the stirring and excavating shaft 5, and an upper injection hole 9 for extracting and discharging the stabilizer is provided near the upper end.
Further, a switching valve 10 is provided at a position near the upper end of the stirring and excavating shaft 5. The two stirring and excavating shafts 5 and 5 are mutually restrained by a connecting member 11 at a substantially middle portion in the height direction, and are rotatably supported while maintaining a vertical posture and an interval. In addition, each drive shaft 4, 4 has a total of 2
Although not shown, the two hoses 2, 2 are connected by swivel joints, respectively, and the other ends of the two hoses 2, 2 are connected to individual stabilizer injection machines 3, 3, respectively.

FIG. 2 is an exploded perspective view illustrating the structure of the switching valve 10 provided near the upper end of the stirring and excavating shaft 5 in more detail. An inner pipe 4a is provided in the drive shaft 4 as a conduit for supplying a stabilizing material, in the axial direction of the center of the drive shaft 4, and a hexagonal square hole 21 is provided at the lower end of the inner pipe 4a in the vertical direction. Is formed. A pin hole 23 is provided below the drive shaft 4 in a horizontal direction along a diameter line passing through the approximate center of the square hole 21. On the other hand, an inner pipe 5a is provided in the stirring and excavating shaft 5 in the axial direction of the central portion of the stirring and excavating shaft 5 as a conduit for supplying a stabilizing material. A hexagonal square shaft portion 22 to be fitted is provided, and a seal ring 25 is fitted to the upper end of the square shaft portion 22. Further, a pin hole 27 corresponding to the pin hole 23 is provided substantially at the center of the square shaft portion 22. Therefore, the stirring excavation shaft 5
Is connected to the drive shaft 4 by fitting the square shaft portion 22 into the square hole portion 21 and pinning the pin 24 through the matching pin holes 23 and 27. Thus, as shown in FIGS. 3 and 4, the rotation of the drive shaft 4 can be reliably transmitted to the stirring and excavating shaft 5, and both shafts do not come off. In addition, since the stirring and excavating shaft 5 and the drive shaft 4 are water-tightly connected by the seal ring 25, the stabilizer does not leak from the connecting portion. Switching valve 1
Numeral 0 is installed at a position near the upper end of the stirring and excavating shaft 5. 2 and 3, the switching valve 10 includes a flow path 10a communicating with the upper injection hole 9 and a flow path 10 communicating with the inner pipe 4a of the drive shaft 4 for supplying the stabilizer.
b, and a valve element 12 in which a total of three flow paths of a flow path 10c communicating with the inner pipe 5a of the stirring and excavating shaft 5 reaching the tip injection hole 8 are provided in directions different from each other by approximately 90 degrees in the rotation direction, It comprises a cylinder 13 into which the valve body 12 is rotatably fitted, and a lid 26 screwed to the end face of the valve body 12 from the opposite side so that the valve body 12 does not come off. Therefore, the valve body 12 rotates around a horizontal center line in the cylinder 13 of the valve casing 28. A shaft 14 that penetrates the center of the lid 26 protrudes from the end face thereof along the center line of the valve body 12, and the coaxial 14 has a wide rectangular (rectangular) conversion blade suitably receiving the action of earth pressure. 15 are mounted vertically downward. In this embodiment, the switching valve 10 is installed at substantially the same height as the upper injection hole 9, but may be installed above or below the upper injection hole 9 as necessary.

FIG. 4 is an enlarged view of the structure of the stirring and excavating shaft 5 connected to the lower end of the drive shaft 4, and as is apparent from FIG. An annular body 16 that rotates horizontally along the outer periphery of the ring is provided using upper and lower guide rings 29, 30. The annular body 16 has two switching bars 17a, 17b arranged so as to sandwich the conversion blade 15 therebetween. Is protruding. A positioning piece 18 for restricting the rotation range of the annular body 16 is provided on the rear side of the annular body 16 at a position substantially 180 degrees opposite to the switching bars 17a and 17b (FIGS. 6A and 6B). The switching bars 17 a and 17 b and the positioning piece 18 are configured to rotate together with the ring 16. On the other hand, two stoppers 19a, 19b against which the positioning piece 18 abuts are provided on the upper and lower guide rings 29, 30.
Are fixedly provided at two positions where the rotation range of the ring 16 is to be regulated (FIGS. 6A and 6B).

Accordingly, this ground improvement device is, for example, shown in FIG.
When the drive shaft 4 is rotated in the direction of the arrow X (clockwise) as shown in A, the switching blade 15 of the switching valve 10 rotates in the direction of the arrow a under the action of the earth pressure and moves to the switching bar 17b on the right side. And the ring 16 together with the switching bar 17b
Push counterclockwise. Then, the valve body 12 rotates together with the conversion blade 15, and the inner pipe 4 a of the drive shaft 4 communicates with the flow path 10 a of the valve body 12, and the inner pipe 5 a of the stirring and excavating shaft 5.
The positioning piece 18 that rotates together with the ring body 16 at the rotational position where the fluid and the flow path 10c communicate with each other is provided with one stopper 19b.
In this case, the ring 16 is stopped (FIG. 6A), and thereafter the switching valve 10 keeps the state of FIGS. 5A and 6A. Therefore, the stabilizer or bentonite mud supplied to the inner pipe 4a of the drive shaft 4 is supplied to the switching valve 10
Through the tip injection hole 8.

Next, when the drive shaft 4 is rotated in the direction of arrow Y (counterclockwise) in the reverse direction as shown in FIG.
Again rotates in the direction of arrow b due to the action of earth pressure, hits the switching bar 17a on the left side at this time,
The ring 16 is rotated clockwise through the switching bar 17a. 5A, the switching blade 15 rotates about 90 degrees, and as shown in FIG. 5B, the flow path 10a of the valve body 12 communicates with the upper injection hole 9, and the inner pipe 4a of the drive shaft 4 and the flow of the valve body flow. When the path 10b is in communication, the positioning piece 18 of the ring 16 hits the other stopper 19a and the ring 16 is stopped (FIG. 6B). Therefore, the stabilizer supplied to the inner pipe 4 a of the drive shaft 4 is discharged from the upper injection hole 9 via the switching valve 10.

Next, an embodiment of a ground improvement method using the ground improvement apparatus having the above-described configuration will be described. In the case of two or more shafts, the rotation of each drive shaft 4 is set to the opposite direction in consideration of the stirring effect between the excavated soil and the stabilizing material.
As shown in FIG. 1, the switching valve 10 is installed in such a manner as to open the flow path to the distal end injection hole 8 as shown in FIG. However, in the excavation stage, dry excavation without injecting stabilizer is usually performed.

At the time when the excavation of the ground reaches a height position for improving the solidified portion before the predetermined depth, the stabilizer injection machine 3
To feed the stabilizer. At this time, switching valve 1
5 is as shown in FIG. 5A as already described, the stabilizer supplied to the inner pipe 4a of the drive shaft 4 passes from the switching valve 10 via the inner pipe 5a of the stirring and excavating shaft 5,
Finally, it is poured out from the tip injection hole 8. In this way, the injection (penetration and discharge) of the stabilizer is started from the tip injection hole 8, and the excavation and the stirring and mixing of the soft ground are advanced to the planned depth to form a reinforced portion. From the stage when the excavation reaches the planned depth, in order to perform the extraction discharge, the rotation of each drive shaft 4 is rotated in a direction opposite to the direction of the excavation, and the stabilizing material is injected while the drive shaft 4 is extracted and agitated and mixed. I do. When the rotation of the drive shaft 4 is reversed, the switching valve 10 switches to the state shown in FIG. 5B under the action of the earth pressure, so that the flow path 10a of the valve body 12 communicates with the upper injection hole 9 and the drive shaft The inner pipe 4a and the flow path 10b communicate with each other. Therefore, the stabilizer supplied to the inner pipe 4 a of the drive shaft 4 is discharged from the upper injection hole 9 via the switching valve 10. Thus, the improved earth column is formed by performing the stirring and mixing process in the process of lifting the stirring and excavating shaft 5 to the ground while injecting (drawing and discharging) the stabilizer from the upper injection hole 9. Forming an improved ground by continuously connecting a large number of such improved soil columns in a plane is exactly the same as the conventional method.

[0014]

According to the ground improvement apparatus of the present invention, one hose and one swivel joint can be provided for one shaft, so that the structure is simple and facility work is easy. Further, since only one swivel joint is required, the equipment cost is correspondingly low and the maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a front view showing an entire configuration of a ground improvement device.

FIG. 2 is an exploded perspective view showing a switching valve.

FIG. 3 is a sectional view showing a connection portion between a drive shaft and a stirring and excavating shaft.

FIG. 4 is a front view showing a lower structure of the ground improvement device.

FIGS. 5A and 5B are front views showing an arrangement relationship between a stirring blade and a switching valve.

FIGS. 6A and 6B are plan views showing an arrangement relationship between a stirring blade and a switching valve.

FIGS. 7A and 7B are an overall view of a ground improvement apparatus showing a conventional technique and a front view showing a lower structure of the apparatus, respectively.

[Explanation of symbols]

 Reference Signs List 4 drive shaft 5 stirring and excavating shaft 6 drilling cutter 7 stirring blade 8 tip injection hole 9 upper injection hole 10 switching valve 12 valve body 14 shaft 15 conversion blade 17a switching bar 17b switching bar 16 ring body 18 positioning piece 19a stopper 19b stopper

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-300109 (JP, A) JP-A-3-199521 (JP, A) JP-A-62-77229 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) E02D 3/12

Claims (1)

(57) [Claims] An upper end of a stirring and excavating shaft is connected in series to a lower end of a drive shaft rotatably supported in a vertically downward arrangement, and excavating soft ground at a lower end of the stirring and excavating shaft. A plurality of agitating blades are provided in the upper part, a tip injection hole for penetrating and discharging the stabilizer is provided at the tip, and an upper injection hole for extracting and discharging the stabilizer is provided at the upper part. In a soil improvement apparatus for excavating soft ground, injecting a stabilizer into excavated soil at the original position, stirring and mixing with the soil to improve soft ground, a switching valve is provided at a position near an upper end portion of the stirring and excavating shaft. Being provided, the switching valve has a valve body having at least three of a flow path communicating with a stabilizer supply hose, a flow path communicating with the upper injection hole, and a flow path communicating with the tip injection hole. But horizontal center It is configured to be rotatably installed with a conversion blade attached substantially downward to a shaft protruding along the center line of the valve element. The switching blade is sandwiched, and the rotation and stop of the valve element are performed. Two switching bars are protruded from a ring that rotates along the outer periphery of the stirring and excavating shaft, and a positioning piece that regulates a rotation range of the ring is protruded from the ring, and the positioning piece is A ground improvement device, wherein stoppers are fixedly provided on the outer peripheral surface of the stirring and excavating shaft at two positions where the stopper abuts at a predetermined rotation angle.