JP2006291702A - Ground improving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground improving device capable of simplifying process control/process management, reducing cost, coping with unevenness of the ground, and preventing occurrence of a region causing shortage of a solidifying material. <P>SOLUTION: Stirring blades M1, M2 are provided above and below a rotary rod R, and nozzles N1, N2 for causing crossing jet stream are provided at tips of these stirring blades M1, M2. The nozzles N1, N2 have a double structure to inject the solidifying material from an inner pipe Ti and inject high pressure air from an outer pipe To. The rod R is pulled up while rotating the rod R to cut and improve the ground by the crossing jet stream. A low pressure solidifying material discharge nozzle N3 is provided in the outside in the radial direction of the rod R in an intermediate part of the upper and lower stirring blades M1, M2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ground improvement method for forming an underground solid body in a ground to be improved by using a cross jet, and a solidifying material injection device used therefor.

  Insert a rod with horizontal blades, spray a high-pressure crossed jet of solidified material from the top of the pair of upper and lower horizontal blades, rotate the rod and cut and agitate the ground with the high-pressure crossed jet of solidified material, There is a ground improvement method that raises to the ground side and creates a cylindrical underground solid body.

When a high-pressure crossing jet of solidified material is jetted from the tip of a pair of upper and lower horizontal blades to form a cylindrical underground solid body (see, for example, Patent Document 1), There is a drawback that the concentration of the solidified material around the inner rod is diluted as compared with the concentration of the solidified material in the vicinity of the outer periphery of the stirring portion.
In the ground improvement method, the solidified material is discharged from the rod at a relatively low pressure in order to satisfactorily improve the area inward in the radial direction from the tip of the horizontal blade.

  Here, when discharging the low-pressure solidified material, in the drawing type (type in which the solidified material is discharged at the time of drawing), as shown in FIG. 9, the horizontal blade agitation must be performed unless the low-pressure solidified material is discharged from above the horizontal blade. Good mixing is difficult due to the effect. On the other hand, in the penetration type (type that discharges solidified material at the time of penetration), as shown in FIG. 10, the solidified material is discharged at a low pressure from below the lowermost horizontal blade, and stirred by the horizontal blade to solidify with the ground. The material is mixed.

Of the above two types of construction methods, the penetration type is common, but when performing construction on ground where the soil property of the ground where the ground improvement method is constructed varies and the penetration speed cannot be controlled constant. Uses a pull-out type construction method.
However, in the drawing type, since the solidified material having a low discharge pressure is discharged from above the horizontal blades before the ground cutting by the cross jet, the solidified material is difficult to turn between the horizontal blades when positioned at the deepest part.
Therefore, the problem that the solidified material is insufficient in the region has occurred.

In order to cope with the above problem, it is conceivable to discharge a low-pressure solidified material from above and below the pair of upper and lower horizontal blades.
However, in that case, in addition to forming the flow path for the high pressure jet and the flow path for the high pressure gas in the rod, in order to independently control the discharge of the low pressure solidified material vertically, It is necessary to use a multi-pipe more than a heavy pipe, and there remains a problem that the structure of the joint and the entire apparatus becomes complicated.

Furthermore, in the prior art, in order to make the diameter (or strength) of the consolidated body formed by the cross jet flow uniform, it is necessary to control the pulling speed of the rod to be constant. For this reason, it may be necessary to inject the solidified material more than necessary, which has been a factor in increasing costs.
Japanese Patent Application Laid-Open No. 07-252823

  The present invention has been proposed in view of the above-described prior art, simplifies apparatus and process management, can reduce costs, can cope with variations in soil soil properties, and lacks solidification material. It aims at providing the ground improvement apparatus which can prevent that the area | region to perform arises.

 The ground improvement device of the present invention is provided with stirring blades M1 and M2 above and below the rotating rod R, and nozzles N1 and N2 that generate cross-jets are provided at the tips of the stirring blades M1 and M2. It is made up of a solid material ejected from the inner pipe Ti and high-pressure air is ejected from the outer pipe To. The rod R is pulled up while rotating the rod R, and the ground is cut by a cross jet, In the ground improvement device for improving the above, a low pressure solidification material discharge nozzle N3 is provided radially outwardly on the intermediate rod R of the upper and lower stirring blades M1, M2.

  Further, the ground improvement device of the present invention is provided with stirring blades M1 and M2 above and below the rotating rod R, nozzles N1 and N2 that generate cross jets at the tips of the stirring blades M1 and M2, and the nozzles N1 and N2. Is a double, which ejects solidified material from the inner tube Ti and ejects high-pressure air from the outer tube To, and pulls the rod R while rotating the rod R and cuts the ground by cross jets. In the ground improvement device for improving the ground, a low pressure gas discharge nozzle N30 is provided radially outward on the rod R intermediate between the upper and lower stirring blades M1 and M2.

  According to the present invention having such a configuration, construction can be performed by the same apparatus regardless of whether the low-pressure solidifying material is discharged or penetrated.

  Here, the nozzle at the tip of the horizontal wing is constituted by a double pipe, and a high-pressure solidified material is formed from a central tubular body by a central tubular body and an outer tubular body, that is, an annular pipe. The body is configured to inject high-pressure air. Therefore, in the cross jet, the solidified material jet is surrounded by the air jet, and the air of the air jet bounces back to the ground wall to be cut and rises to form an updraft.

  On the other hand, the trajectory of the arrival point of the high-pressure crossing jet draws a spiral. Due to the synergistic action of this and the trajectory of the updraft, the ground and solidified material cut by the solidified material jet are agitated and mixed evenly over the entire area, preventing the lack of solidified material. To do.

  By adjusting the discharge amount of the low-pressure solidifying material, it is possible to control the blending amount (or addition amount) of the solidifying material with respect to the improved volume, the rod lifting speed can be made uniform, and the construction can be facilitated and the cost can be reduced.

Further, when gas is injected instead of the low-pressure solidified material, a negative pressure is generated in the region between the horizontal blades due to the rising airflow of the low-pressure air, and the solidified material injected from the horizontal blades by the action of the negative pressure Even if it tries to be separated from the horizontal wing, it is sucked into the area between the horizontal wings.
Therefore, the amount of ascending airflow can be adjusted by adjusting the discharge amount (or discharge pressure) of low-pressure air, and the amount of solidified material sneak around from the surroundings can be adjusted.

  As described above, since the control of the blending amount (or addition amount) of the solidifying material with respect to the improved volume can be adjusted other than the pulling speed, the rod pulling speed can be made constant, and efficient construction is facilitated.

In the practice of the present invention, it is preferable to provide a separate wing above the horizontal wing located directly above the lowest horizontal wing.
By providing such a wing, the soil can be finely crushed during penetration. As a result, the slime (mud) fluidity can be improved and the slime discharge efficiency can be improved at the time of drawing.

  Furthermore, it is preferable to provide a drill bit on the lower side of the lowermost horizontal blade instead of the stirring head. By doing so, the soil is crushed at the time of intrusion, and the mixing and stirring efficiency is improved.

The effects of the present invention are listed below.
(A) The solidifying material injection device can be simplified.
(B) Process control and process management can be simplified.
(C) Since the solidifying material injection device can be simplified and the process control and process management can be simplified, the construction period can be shortened and the cost can be reduced.
(D) It can cope with ground variations.
(E) Does not cause a solidified material shortage region (homogenized improved soil is achieved). (F) The slime (drainage) discharge efficiency is improved.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
1 and 2, the solidified material injection device generally indicated by the symbol F includes a rod R, a lowermost first horizontal blade M <b> 1 orthogonal to the rod R, and a second horizontal blade M <b> 2 immediately above the rod. And a low-pressure solidified material discharge nozzle N3 provided in the region of the rod R between the first horizontal blade M1 and the second horizontal blade M2.
In FIG. 1, the position of the nozzle N3 indicated by a broken line can be displaced. In FIG. 2, Do represents the trajectory of the arrival point of the cross jet JJ, and Di represents the trajectory of the tips of the nozzles N1 and N2 provided at the tips of the first horizontal blade M1 and the second horizontal blade M2, which will be described later. To express.

  The nozzles N1 and N2 are composed of a double pipe having an inner pipe Ti and an outer pipe To as shown in FIG. 4 which is a partial sectional view of FIG. 3 and an XX sectional view of FIG. High-pressure solidified material is ejected from the tube Ti, and high-pressure air is ejected from an annular channel t defined by the inner tube Ti and the outer tube To.

  Returning to FIG. 1, therefore, the cross jet JJ constituted by the high-pressure jets J1 and J2 of the solidified material is surrounded by the high-pressure air jet ja1 and is urged by the high-pressure air jet ja1. The low-pressure solidified material discharge nozzle N3 discharges a low-pressure solidified material discharge flow Jb.

  1 and 2, Y1 indicates the rotation direction of the rod, and Y2 and Y3 indicate the vertical movement of the solidifying material injection device F.

  According to the present invention having such a configuration, as shown in FIG. 5 (state diagram at the time of ground cutting), the solidifying material injection device F rotates the rod R in the Y1 direction while the nozzle N1 at the tip of the first horizontal blade, And the high-pressure jets J1 and J2 of the solidified material are ejected from the nozzle N2 at the tip of the second horizontal blade M2, thereby forming a cross jet JJ.

The tip of the cross jet JJ collides with the ground E, and this is excavated and crushed. At this time, the periphery of the high-pressure jets J1 and J2 of the solidified material is surrounded by a high-pressure air jet ja1 ejected from an annular flow path t formed by the inner pipe Ti and the outer pipe To of the nozzle, The momentum of the high-pressure jets J1 and J2 of the solidified material does not decrease.
The high-pressure air jet ja1 collides with the wall surface and then becomes an ascending airflow ja2 and is released to the atmosphere from an opening (not shown) around the rod B.

  On the other hand, a low-pressure solidified material is discharged as a discharge flow Jb from the low-pressure solidified material discharge nozzle N3. The discharge flow after discharge draws a spiral locus jb as shown in FIG.

  In the prior art, the low-pressure solidified material is not discharged, and the ground and the high-pressure solidified material are excavated and crushed in an area surrounded by the first and second horizontal blades M1 and M2 and the high-pressure jets J1 and J2 of the solidified material. However, in the present invention, the pulverized ground and the solidified material are separated by the discharge flow Jb of the low pressure solidified material from the low pressure solidified material discharge nozzle N3. Mixing and stirring can be performed efficiently, the concentration of the solidified material can be increased, and a homogeneous improved ground can be obtained.

  Further, as shown in FIG. 7, the ground and the solidified material further pulverized by wrapping the spiral flow SJ in which the crossed jet JJ, the high pressure air jet ja1 and the discharge flow Jb of the low pressure solidified material are mixed with each other. Can be easily mixed and stirred.

Furthermore, the concentration of the solidified material can be controlled by adjusting the discharge amount of the low-pressure solidified material while keeping the rod pulling speed constant, so that uniform ground improvement, easy construction and cost reduction can be achieved.
In addition, the same type of equipment can be used regardless of whether it is an intrusion type or a pull-out type.

A second embodiment of the present invention will be described with reference to FIG.
The solidifying material injection device indicated as a whole by the symbol F is different from the first embodiment described above except that the low pressure solidifying material discharge nozzle N3 is replaced with a low pressure gas discharge nozzle N30, and low pressure air is used as the gas. Are the same. Different points will be described with a focus on action and effect.

The solidifying material injection device F injects the high-pressure jets J1 and J2 of the solidifying material from the nozzles N1 and N2 while rotating the rod R in the Y1 direction, thereby forming a cross jet JJ.
At this time, the periphery of the high-pressure jets J1 and J2 of the solidified material is surrounded by the high-pressure air jet ja1 by the same mechanism as that of the first embodiment, and the momentum of the high-pressure jets J1 and J2 of the solidified material decreases. Absent.
The tip of the cross jet JJ excavates and crushes the ground (not shown).

On the other hand, from the low-pressure gas discharge nozzle N30, an air jet Jc having a pressure lower than the atmospheric pressure but lower than the high-pressure air jet ja1 is jetted in a direction (horizontal direction) perpendicular to the rod R axis.
On the other hand, the high-pressure cross jet JJ and the air jet ja1 cut the ground, and the cutting pieces of the ground are drawn to the center (rod R axis side) by the pressure difference with the low-pressure air jet Jc. That is, negative pressure is generated in the region between the horizontal blades by the low-pressure air, and the solidified material injected from the horizontal blades is sucked into the region between the horizontal blades even if trying to separate from the horizontal blades by the action of the negative pressure. .
The high-pressure jet that cuts the ground mixes with the low-pressure air jet Jc to form an updraft jac and escape upward.

  Therefore, the amount of the rising air flow is adjusted by adjusting the discharge amount of the low-pressure air or the high-pressure cross jet JJ and the air jet ja1 injected from the tip of the horizontal blade, thereby adjusting the amount of the solidified material from the surroundings. Can do.

  According to the ground improvement device of the present invention having such a configuration, the device and process management can be simplified, the cost can be reduced, the variation of the ground can be dealt with, and there is a region where the solidification material is insufficient. Can be prevented.

It should be noted that the illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention.
For example, in the illustrated embodiment, a high-pressure solidified material jet is injected in two directions from the solidified material injection device, but the present invention is not limited only to the case of injecting in two directions. The solidified material may be injected only in one direction, or the solidified material may be injected in three or more directions.

The side view which shows 1st Embodiment of this invention. The top view of FIG. FIG. 2 is a partial cross-sectional detail view of nozzles N1 and N2 of FIG. XX sectional drawing of FIG. The figure which shows the state which is cutting the ground in 1st Embodiment of this invention. FIG. 6 is a plan view of FIG. 5 showing the trajectory of the injected solidified material. The figure which shows the locus | trajectory of the injected solidified material and an updraft. The side view which shows 2nd Embodiment of this invention. The side view which shows a prior art. The side view which shows other prior art.

Explanation of symbols

F ... Solidified material injection device J1 ... Solidified material jet Ja1 ... Air jet Ja2 ... Ascending airflow JJ ... Crossed jet M1 ... First horizontal blade M2 ... Second Horizontal blade N1 ... Nozzle R ... Rod

Claims (2)

Agitating blades (M1, M2) are provided above and below the rotating rod (R), and nozzles (N1, N2) for generating a cross jet are provided at the tips of the agitating blades (M1, M2). The nozzles (N1, N2) Is a double layer that ejects solidified material from the inner tube (Ti) and ejects high-pressure air from the outer tube (To). Pulling the rod (R) while rotating the rod (R) In the ground improvement device for cutting the ground by cross jets to improve the ground, a low pressure solidification material discharge nozzle is provided radially outward on the intermediate rod (R) of the upper and lower stirring blades (M1, M2). Features ground improvement device. Agitating blades (M1, M2) are provided above and below the rotating rod (R), and nozzles (N1, N2) for generating a cross jet are provided at the tips of the agitating blades (M1, M2). The nozzles (N1, N2) Is a double layer that ejects solidified material from the inner tube (Ti) and ejects high-pressure air from the outer tube (To). Pulling the rod (R) while rotating the rod (R) In the ground improvement device for improving the ground by cutting the ground by cross jets, a low pressure gas discharge nozzle is provided radially outward on the intermediate rod (R) of the upper and lower stirring blades (M1, M2). Ground improvement device.

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