JPH11350468A - Ground improving method and ground improving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground improving method and its device for improving the ground by fitting a stirring head having the discharge ports of an improving material at the upper and lower sections of a rod body to the tip of an excavation rod, switching the discharge ports, and stirring and mixing the improving material and soil to improve the ground. SOLUTION: A stirring head 1 fitted to the tip of an excavation rod has a single-tube structure, an upper discharge port 3 is provided at the upper section of the stirring head 1, and a lower discharge port is provided at the lower section respectively. An upper/lower discharge port switching mechanism 20 utilizing the difference of the soil pressure applied when the rod is intruded and lifted is provided on the rod body, the improving material is discharged from the lower discharge port by the discharge port switching mechanism 20 when the rod is introduced and from the upper discharge port 3 when the rod is lifted respectively, and the improving material and soil are stirred and mixed to improve the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavating rod in which a stirring head having a discharge port for improving material is mounted on the upper and lower portions of a rod body, and the discharging port is switched to stir and mix the improving material and soil. And a device for improving the ground.

[0002]

2. Description of the Related Art Conventionally, as a technique for improving the ground by switching the upper and lower discharge ports provided in a stirring head to discharge an improving material, for example, Japanese Patent Publication No. 5-62167 and Japanese Patent Publication No. 6-39779 are disclosed. Have been. However, all of these techniques have a problem that since the stirring head has a double pipe structure, the structure becomes complicated and the apparatus becomes large.

[0003]

Japanese Patent Application Laid-Open No. Hei 6-146267 has proposed a discharge switching device for a stirring head having a single tube structure. This device is configured such that the upper housing and the lower housing are covered with the upper stirring blade and the lower stirring blade, respectively, and each housing moves up and down by a certain stroke relatively.However, the device becomes large and heavy, Problems such as increased penetration resistance and inability to penetrate depending on the soil quality are not solved.

Further, there is a method of switching the discharge port by rotating the stirring head forward and backward. However, this method limits the rotation direction of the stirring head. There is a problem that you can not do. Further, there is a problem that none of the conventional techniques has a means for confirming whether or not the upper and lower discharge ports are properly switched.

The present invention has been made in order to solve these problems, and the discharge port of the improved material is switched by a simple upper and lower discharge port switching mechanism, and the discharge port is appropriately switched. It is an object of the present invention to provide a ground improvement method for improving the ground while checking whether or not the ground is present, and an apparatus used therefor.

[0006]

According to the present invention, to solve these problems, a plurality of stages of stirring blades are attached to a rod body of a hollow rod having an improved material flow passage, and the upper and lower parts of the rod body are provided. In the ground improvement method of improving the ground, the agitation head provided with each of the improvement material discharge ports is agitated and mixed with the soil and the improvement material discharged from the discharge port of the agitation head of the ground improvement device attached to the tip of the drilling rod. ,
The stirring head of the ground improvement apparatus has a single pipe structure, and an upper discharge port is provided at an upper portion of a rod body of the stirring head, and a lower discharge port is provided at a lower portion thereof. The upper and lower discharge port switching mechanism used is provided on the rod body, and the discharge port switching mechanism discharges the improving material from the lower discharge port when the rod penetrates and from the upper discharge port when pulling up the rod, and stirs and mixes the improving material and soil. This is a ground improvement method for improving the ground.

In addition, a plurality of stages of agitating blades are provided in a rod body of a hollow rod having an improved material flow passage, and a stirrer head in which discharge ports communicating with the improved material flow passage are provided at upper and lower portions of the rod body, respectively. In the soil improvement device attached to the tip of the rod, the stirring head has a single-tube structure,
In addition, a switching wing is attached to the rod body so as to be able to move up and down by a fixed distance by earth pressure acting when the rod penetrates and lifts up, and a stop valve provided on a connecting rod of the switching wing moves up and down the improvement material flow passage at the time of penetration. An upper and lower discharge port switching mechanism that communicates with the upper discharge port and closes the improved material flow passage of the lower discharge port when the rod is lifted is provided above the upper stirring blade, and the upper discharge port is opened at a certain fluid pressure or higher. That is, the ground improvement device is provided with a stop valve.

Further, a stirring head in which a plurality of stages of stirring blades are provided in a rod body of a hollow rod having an improvement material flow passage, and improvement material discharge ports communicating with the improvement material flow passage are provided at upper and lower portions of the rod body, respectively. In the ground improvement device attached to the tip of the excavation rod, the stirring head has a single pipe structure, and a switching blade having a connecting rod at a position deviated from the center position in the width direction of the blade body, A passage of a passage switching valve having two passages having different diameters, which is attached to the upper part of the upper stirring blade and is interposed in the improved material flow passage by the rotation of the switching blade and the connecting rod accompanying the penetration and lifting of the rod, When the rod penetrates, it goes to the lower discharge port.
This is a ground improvement device provided with an upper and lower discharge port switching mechanism communicating with the upper discharge port.

Another object of the present invention is to provide a ground improvement device for confirming switching of the upper and lower discharge ports by reading the scale of a pressure gauge of an injection pump.

The present invention has the above configuration. The following effects are obtained. Since the stirring head body has a single tube structure, the structure is simple and handling is easy. Since the upper and lower discharge ports are switched by the vertical movement of the stirring head, the discharge ports can be switched regardless of the rotation direction of the stirring head. It is economical because no drive (power) source is required to switch the upper and lower discharge ports. By providing a check valve that opens above the fluid pressure at the upper discharge port, it is possible to check whether the upper and lower discharge ports are properly switched by reading the pressure gauge of the infusion pump. The use of a passage switching valve having two passages with different diameters for switching to the upper and lower discharge ports. By reading the pressure gauge of the infusion pump, it is possible to confirm whether or not the upper and lower discharge ports have been properly switched.

[0011]

Embodiments of the present invention will be described below with reference to examples. FIG. 1 is an overall front view of a stirring head of a ground improvement apparatus used in the ground improvement method according to claim 1 of the present invention. A stirring head 1 of the improved apparatus has a rod body 2 having a single-tube structure, a plurality of stages of stirring blades 6 and 7 protrudingly provided on the rod body 2, and an upper discharge port 3 at an upper part of the rod body and a lower part at a lower part. Are provided with lower discharge ports 4 respectively, and upper and lower discharge port switching mechanisms 20, 20a shown in FIGS.

The upper / lower discharge port switching mechanism 20 of the improved material has the following configuration. As shown in FIG. 2, the switching blade 5 is provided above the upper stirring blade 6 (not shown in FIG. 2) provided below the upper discharge port 3 of the rod body 2 having the improved material flow passage 11. The switching blade 5 is connected to a stop valve 9 provided in a partially enlarged portion 11a of the improved material flow passage 11 of the rod body 2 by a connecting rod 8, and is connected to the switching blade 5 when the rod penetrates or is pulled up. Due to the acting earth pressure, the rod body 2
It is mounted so that it can move up and down by a certain distance in the up and down direction. In addition, a check valve 10 that opens at a certain fluid pressure or higher is installed at the upper discharge port 3.

The stirring head 1 constructed as described above is mounted on a drilling rod (not shown) and penetrates the ground while rotating the drilling rod. In this case, since an upward earth pressure acts on the stirring head 1, the switching blade 5 attached to the rod body 2 so as to be vertically movable by a predetermined distance is pushed up to the upper end position (the position shown by a solid line in FIG. 2). Stop.

At this time, the stop valve 9 attached to the connecting rod 8 connected to the switching blade 5 rises inside the partially enlarged portion 11a of the improved material flow passage 11 as the switching blade 5 rises. When the switching blade stops at the upper end position, the stop valve 9 also stops in a state where the improved material flow passage 11 is communicated with the lower discharge port 4. In this case, the upper discharge port 3 is also in communication, but the discharge of the improving material is performed through the lower discharge port 4 at a pressure equal to or lower than the fluid pressure at which the check valve 10 provided in the upper discharge port is opened. No discharge is performed from the upper discharge port 3 by the action of the stop valve 10. After excavating and stirring to a predetermined depth while discharging the improving material from the lower discharge port 4 in this manner, the excavating rod is pulled up while rotating.

In the case where the excavating rod is rotated and raised, a downward earth pressure acts on the stirring head 1 in a direction opposite to that at the time of penetration, so that the switching blade 5 is pushed down to the lower end and stopped.
(Positions indicated by dotted lines in FIG. 2). At this time, the stop valve 9 also descends, stops in a state fitted in the improved material flow passage 11, closes the improved material flow passage 11b to the lower discharge port, and connects the improved material flow passage 11 to the upper discharge port 3. Communicate. In this state, the improvement material is discharged from the upper discharge port 3 with the pressure of the fluid pressure at which the check valve 10 provided in the upper discharge port 3 opens, and pulled up while rotating the excavation rod to improve the ground.

In order to prevent inflow of earth and sand into the lower discharge port 4, a check valve that opens at a pressure lower than the fluid pressure at which the check valve 10 of the upper discharge port 3 opens may be provided. Whether or not the upper and lower discharge ports 3 and 4 are properly switched is confirmed by reading the pressure gauge of the injection pump, though not shown. That is, when the improving material is discharged from the upper discharge port 3, the reading of the pressure gauge indicates a value equal to or higher than the pressure value at which the check valve 10 of the upper discharge port 3 is opened, and the pressure gauge is discharged from the lower discharge port 4. If present, indicate a value less than that. In the embodiment, the shape of the stop valve 9 is spherical. However, the shape is not limited to this, and various shapes such as a conical shape can be considered.

Next, a description will be given of an embodiment of a ground improvement apparatus according to the third aspect and a construction method using the same. As shown in FIG. 3, the switching blade 5a is attached to the rod body 2 by the connecting rod 8a at a position deviated from the center position in the width direction of the blade body. In the middle of the improved material flow passage 11 inside the rod body, FIG.
As shown in the figure, a passage switching valve 12 having passages 13a and 13b having different diameters is interposed, and the improved material flow passage is formed by switching two passages (13a and 13b) having different diameters of the passage switching valve 12. Upper and lower outlet switching mechanism 20 having a structure in which 11 communicates with upper outlet 3 and lower outlet 4, respectively.
a is provided. The passage switching of the passage switching valve 12 is performed as follows.
It is configured to be performed by the rotation of the switching blade 5a and the connecting rod 8a (see FIG. 4).

The stirring head constructed as described above is attached to a drilling rod (not shown), and penetrates the ground while rotating the drilling rod. In this case, since an upward earth pressure acts on the stirring head, the switching blade 5a and the connecting rod 8
a rotates around the connecting rod to the position shown by the solid line in FIG. 4, the passage of the passage switching valve 12 becomes as shown in FIG. Is communicated with the lower discharge port 4 through the large-diameter passage 13a.

In this state, after the improving material is discharged from the lower discharge port 4 to excavate and agitate to a predetermined depth, the excavating rod is pulled up while rotating. In this case, since downward earth pressure acts on the stirring head, the switching blade 5a and the connecting rod 8a
4 rotates about the connecting rod to the position shown by the dotted line in FIG. 4, the passage of the passage switching valve 12 becomes as shown in FIG. Passage 1
3b communicates with the upper discharge port 3. In this state, the improvement material is discharged from the upper discharge port 3 and the excavating rod is rotated and pulled up to perform the ground improvement.

Whether the upper and lower discharge ports are properly switched is confirmed by reading the pressure gauge of the infusion pump.
That is, when the improving material is discharged from the upper discharge port, since the improved material is communicated with the small-diameter passage 13b of the passage switching valve 12, the discharge from the lower discharge unit 4 communicated with the large-diameter passage 13a of the passage switching valve 12 is performed. The pressure gauge reading gives a higher value than sometimes. The upper discharge port 3 is connected to the large-diameter passage 13a and the lower discharge port 4
Are communicated through the small-diameter passage 13b, when the improving material is discharged from the upper discharge port 3, the pressure gauge reading shows a lower value than when discharged from the lower discharge port 4.

As can be seen from the above embodiments, the method and apparatus of the present invention allow efficient agitation and mixing of the improving material and soil with all of the stirring blades in a plurality of stages both when the drilling rod penetrates and when it is lifted. Can be. In this embodiment, a switching blade is separately provided above the upper stirring blade. However, the switching blade naturally has the function of a stirring blade, and the upper stirring blade is a switching blade. Of course, it can be configured.

The method of the present invention is not limited to the mechanical stirring method, but can be sufficiently applied to the switching of the chemical flow path in various fields such as high-pressure injection, horizontal improvement, and chemical injection.

[0023]

As a result of performing the ground improvement by the ground improvement method according to the present invention, the effects as described in the operation section of this specification can be confirmed, and an improved body of uniform quality can be obtained. Could be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of the entire stirring head used in the ground improvement method of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of an upper and lower discharge port switching mechanism of a stirring head according to a second embodiment.

FIG. 3 is a schematic sectional view of a main part of an upper / lower discharge port switching mechanism of a stirring head according to a third embodiment.

FIG. 4 is a schematic view showing a rotating state of a switching wing and a connecting rod according to a third embodiment.

FIG. 5 is a schematic view showing an operation state of a passage switching valve of the upper and lower discharge port switching mechanism according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stirring head 2 Head main body 3 Upper discharge port 4 Lower discharge port 5 Switching blade 5a Switching blade 6 Upper stirring blade 7 Stirring blade 8 Connecting rod 8a Connecting rod 9 Stop valve 10 Check valve 11 Improvement material flow path 11a Partial diameter enlargement Part 12 Passage switching valve 13 Passage switching valve passage 20 Upper and lower discharge port switching mechanism 20a Upper and lower discharge port switching mechanism

Claims (4)

[Claims] An agitating head having a plurality of stages of agitating blades attached to a rod body of a hollow rod having an improving material flow passage, and an improving material discharge port provided at upper and lower portions of the rod body, is used for a drilling rod. In the ground improvement method for improving the ground by stirring and mixing the improving material discharged from the discharge port of the stirring head of the ground improvement device attached to the tip and the soil, the stirring head of the ground improvement device has a single pipe structure, An upper discharge port is provided at the upper part of the rod body of the head, and a lower discharge port is provided at the lower part, and an upper and lower discharge port switching mechanism utilizing the difference in earth pressure acting when the rod penetrates and when the rod is lifted is provided in the rod body. The outlet switching mechanism discharges the improving material from the lower discharge port when the rod penetrates and from the upper discharge port when pulling up the rod, and stirs and mixes the improving material with the soil, Ground improvement method characterized by improvement. 2. A stirring head having a plurality of stages of stirring blades provided in a rod body of a hollow rod having an improved material flow passage, and a discharge port communicating with the improved material flow passage provided in upper and lower portions of the rod body, respectively. In the soil improvement device attached to the tip of the rod, the stirring head has a single pipe structure, and a switching blade is attached to the rod body so as to be able to move up and down by a certain distance by earth pressure acting when the rod penetrates and lifts. A stop valve provided on the connecting rod of the switching blade connects the upper and lower discharge port switching mechanism for connecting the improved material flow path to the upper and lower discharge ports when penetrating, and closing the improved material flow path for the lower discharge port when pulling up the rod. A ground improvement device comprising: a check valve provided at an upper portion of a stirring blade; and a check valve that opens at a certain fluid pressure or higher at an upper discharge port. 3. A stirring head having a plurality of stages of agitating blades provided in a rod body of a hollow rod having an improving material flow passage, and an improving material discharge port communicating with the improving material flow passage provided in upper and lower portions of the rod body, respectively. In the ground improvement device attached to the tip of the excavation rod, the stirring head has a single pipe structure,
In addition, a switching blade having a connecting rod at a position deviated from the center position in the width direction of the blade main body is attached to an upper portion of the upper stirring blade of the rod main body, and the switching blade and the connecting rod are rotated by the rod penetrating and lifting. An upper and lower discharge port switching mechanism for connecting a passage of a path switching valve having two paths with different diameters interposed in the improved material flow path to a lower discharge port when the rod penetrates and to an upper discharge port when the rod is pulled up. Ground improvement device characterized by having provided. 4. The ground improvement apparatus according to claim 2, wherein the switching of the upper and lower discharge ports is confirmed by reading the scale of a pressure gauge of the injection pump.