JPH07310315A - Soil improvement method - Google Patents

Abstract

PURPOSE:To draw the peripheral soft soil into the discharging soil zone and prevent the excavation from badly affecting the periphery, by discharging the original soil gradually by the volume corresponding to the delivered solidifying agent at the same time when the solidifying agent is delivered and mixed and agitated on pulling out a rotary shaft body. CONSTITUTION:A rotary shaft body is constituted of a triple-tube composed of an inner pipe 1, an intermediate pipe 2, and an outer pipe 3, which can be changed to an optional rotary direction and a revolutional number respectively. The lower ends of the intermediate pipe 2 and the outer pipe 3 are made a little shorter than the inner pipe in turn respectively. A lower stage excavation and agitation blade 5 and an upper stage agitation blade 6 are fitted to the lower ends of the inner and intermediate pipes 1, 2 respectively. A soil-discharging spiral blade 7 is protrusively formed at the external periphery of the outer pipe 3 and delivery outlets 4, 8 for a solidifying agent slurry are provided at the lower end. After the rotary shaft body has been inserted to a specified depth of a soft ground, the solidifying agent is deliver ed from the outlets of the outer pipe 3 and the outer pipe is rotated reversely. The whole rotary shaft body is pulled out gradually from the ground while rotating the inner pipe and the intermediate pipe to different direction from each other, in order to simultaneously mix and agitate the soft ground with the solidifying agent' and also remove the soft ground to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for carrying out a hardening treatment by stirring and mixing original ground soil while discharging and filling a ground hardening agent into soft ground.

[0002]

2. Description of the Related Art When constructing a soil improvement method in which a slurry-type ground hardening agent such as cement milk is filled and mixed with soft soil, depending on the soil quality of the original ground, the filling of the hardening agent increases the volume of the soil. And ground rise phenomenon,
Lateral movement of the soil may occur and may seriously affect existing surrounding structures.

Therefore, as an effective means for solving this, for example, as described in Japanese Examined Patent Publication No. 4-57805, there is a method of pre-discharging an amount of raw ground soil corresponding to the discharge amount of the curing agent. Recently proposed. However, this method discharges the soil before injecting the hardener, so that the soft soil around the soil is drawn into the soil, causing displacement to the surrounding ground, which also has an adverse effect on the surrounding existing structures. Become.

[0004]

DISCLOSURE OF THE INVENTION The present invention proposes a method which solves the problems in the conventional soil improvement type ground improvement method and enables the earth to be discharged without affecting the surrounding soft ground. To do.

[0005]

SUMMARY OF THE INVENTION The present invention does not discharge the soil before pouring the curing agent, but simultaneously pours the curing agent and discharges the soil. It is made adjustable so that a suitable amount of soft soil can be discharged. For this purpose, the Japanese Patent Publication 6 previously proposed by the applicant.
A device obtained by modifying the inner and outer triple pipe type ground improvement device described in JP-A-4-11771 is used.

That is, according to the present invention, the rotating shaft body is constituted by a triple pipe of an inner pipe, a middle pipe and an outer pipe, each of which can be changed in arbitrary rotation direction and number of revolutions, and the lower ends of the middle pipe and the outer pipe are sequentially arranged from the inner pipe. Shorter, lower digging and stirring blades and upper tier stirring blades are attached to the lower ends of the inner and middle pipes, respectively, and a spiral blade for earth removal is formed on the outer periphery of the outer pipe, and a slurry is formed at the lower end. After penetrating to a predetermined depth of the soft ground while rotating the rotary shaft of the soil improvement apparatus provided with a hardening agent discharge port, the hardening agent is discharged from the lower end discharge port of the outer pipe and the outer pipe is Reverse rotation, while gradually rotating the inner tube and the middle tube in mutually different directions, gradually pulling out the entire rotary shaft body from the ground, mixing and stirring the hardening agent with soft soil and excluding soft soil to the outside of the system. Are performed at the same time. Examples of the method of the present invention will be described below with reference to the drawings.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a ground improvement device used in the method of the present invention. As in Japanese Patent Publication No. 64-11771, an inner tube having a rotating shaft as a center 1, an intermediate middle tube 2, and an outer outer tube. 3, the lower ends of the middle pipe 2 and the outer pipe 3 are sequentially made shorter than the inner pipe 1, and the inner pipe 1 has no lower end port 4 with the lower discharge port 4 of a slurry-like hardening agent such as cement milk. A lower stage excavating and stirring blade 5 is attached to the lower end of the inner pipe 1, and an upper stage stirring blade 6 is attached to the lower end of the middle pipe 2. Also, the outer tube 3
A spiral blade 7 for soil removal is formed on the outer periphery of the outer pipe 3, and an upper discharge port 8 for the slurry-like hardening agent is also provided at the lower end of the outer pipe 3. Each of the pipes 1, 2 and 3 is configured so that the rotation direction and the rotation speed thereof can be arbitrarily converted by a prime mover 9 installed above.

[0008] First, when the device is positioned at a predetermined position on the soft ground 10 to be improved, the prime mover 9 is driven to rotate the inner pipe 1 in the forward direction, and the lower surface excavating blade 5a of the excavating and stirring blade 5 at the lower end thereof. While excavating the ground 10 by
Also, the outer tube 3 is also rotated forward at the same time, and penetrates to a predetermined depth a without discharging the earth (FIG. 2 (a)).

Immediately before the bottom blade 5 leaves a space f between the upper blade 6 and the bottom blade 5 at a predetermined depth a, a slurry-like hardening agent such as cement milk is discharged from the discharge port 4 at the lower opening of the inner pipe 1. It is discharged, and the hardening agent and the surrounding soil are mixed and agitated to the bottom by rotating the lower blade 5 (Fig. 2).
(B)).

When the lower blade 5 reaches a predetermined depth a, the discharge of the curing agent from the inner pipe 1 is stopped, and this time, the upper discharge port 8 provided at the lower end of the outer pipe 3 is passed through the inner side of the outer pipe 3 as well. While the outer tube 3 is rotated in the reverse direction, and the inner tube 2 and the inner tube 1 are rotated in opposite directions, the entire rotary shaft bodies 1 to 3 are gradually pulled out (FIG. 2).
(C)).

As a result, the hardening agent discharged from the upper discharge port 8 is effectively mixed and stirred with the surrounding soil by the upper and lower blades 6 and 5, and the improved pile 11 is formed, and at the same time, the outer pipe is formed. 3 By the rotation of the spiral blade 7 on the outer periphery, the soft soil above the improved pile 11 being constructed is sent upward and is gradually discharged 12 onto the upper surface of the ground 10 (Fig. 2 (d)).

When pulling out this device from the ground 10,
The rotation speeds of the pipes 1 to 3 do not have to be the same, and the ground 1
The soil 12 is discharged in an amount commensurate with the amount of the hardening agent injected into 0, the rotation speed of the outer tube 3 is adjusted according to the soil quality of the soft soil, and the extraction speed of the device is also adjusted according to the discharged amount. In some cases, the extraction may be temporarily stopped and the soil removal and the hardening agent may be stirred and mixed. Also, the outer tube 3
Depending on the amount of soil discharged, the rotation itself is sometimes controlled by temporarily stopping the rotation or returning it to the normal rotation, and the amount of soil discharged is adjusted appropriately so as not to affect the surrounding ground.

As described above, during the formation of the improved pile 11, the lower blades 5 and the upper blades 6 are made to have different rotational directions and rotational speeds from each other so that they are agitated and kneaded so that soil does not adhere to both blades and between them. A uniform and highly accurate pile body 11 is created over the entire area of the pile body 11.

Moreover, during the construction of the pile 11, the untreated soil on the upper side is sequentially discharged out of the system by an amount commensurate with the discharge filling amount of the hardening agent by the rotation of the spiral blade 7 provided on the outer pipe 3. Therefore, the volume of the ground 10 does not increase and the surrounding ground is not displaced.

[0015]

As described above, the present invention eliminates the original ground soil in anticipation of the amount corresponding to the filling amount of the hardening agent in advance when the rotary shaft penetrates the ground, as in the conventional soil-removal type ground improvement method. Unlike the one that is performed, the soil of the soft soil around the soil is discharged in an area where the soil is gradually discharged in an amount commensurate with the discharge amount of the curing agent at the same time as the curing agent is discharged and the mixing and stirring process is performed when the rotary tube is pulled out. There is no adverse effect on the surrounding ground by pulling in.

In addition, the apparatus used in this method is constituted by a triple pipe, and a stirring blade is attached to the lower end of each of the outer pipes having a spiral blade formed on the outer circumference and a hardening agent discharge port provided at the lower end. Since the pipes and inner pipes are projected, by setting the rotation direction and number of rotations of each pipe as desired, it is possible to mix and stir with the curing agent discharged on the lower side when pulling out the equipment and to discharge the soil on the upper side. In addition, the amount of soil discharged can be adjusted freely, and there is no concern that the discharged curing agent will be discharged outside the system together with the discharged soil.

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus used for a ground improvement method according to the present invention.

FIG. 2 is an explanatory view showing a construction process of the ground improvement method according to the present invention.

[Explanation of symbols]

 1-Inner Tube 2-Medium Tube 3-Outer Tube 4-Lower Curing Agent Discharge Port 5-Lower Stage Excavator and Stirrer Blade 6-Upper Stage Stirring Blade 7-Soil Discharge Spiral Blade 8-Upper Curing Agent Discharge Port 9-Motor 10 -Soft ground 11-Improved pile 12-Soil removal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Itsu Koji 3-8-15 Kaigan, Minato-ku, Tokyo Kokuso Shibaura Building National Land Construction Co., Ltd. (72) Inventor Hitoshi Matsushima Minato-ku, Tokyo Kaigan 3-8-15 Kokuso Shibaura Building National Land Construction Co., Ltd.

Claims (4)

[Claims] 1. A rotary shaft is composed of a triple pipe of an inner pipe, a middle pipe, and an outer pipe, each of which can be changed in an arbitrary rotation direction and number of revolutions. A lower stage excavating and stirring blade and an upper stage stirring blade are attached to the lower ends of the inner pipe and the middle pipe, respectively, and a spiral blade for earth removal is formed to project on the outer periphery of the outer pipe and a slurry-like hardening agent is formed at the lower end. After rotating the rotary shaft of the ground improvement device provided with a discharge port to penetrate the soft ground to a predetermined depth, the hardening agent is discharged from the lower end discharge port of the outer pipe and the outer pipe is rotated in the reverse direction. Also, while gradually rotating the inner tube and the middle tube in different directions, the entire rotary shaft is gradually pulled out from the ground to simultaneously mix and stir the hardening agent with the soft soil and remove the soft soil from the system at the same time. The ground improvement method is characterized in that 2. The ground improvement method according to claim 1, wherein when the rotary shaft is pulled out, the rotation speed of the outer pipe is adjusted according to the soil quality of the soft soil so that the soil is discharged in an amount corresponding to the discharge amount of the curing agent. . 3. The lower end opening of the inner pipe serves as the lower discharge opening of the slurry-like hardening agent, and the distance between the upper and lower stirring blades immediately before the rotary shaft penetrates the bottom of the soft ground to a predetermined depth. After leaving only, discharge the curing agent from the lower discharge port,
The stirrer and surrounding soil are mixed and stirred up to the bottom of the land.
Ground improvement method described. 4. The lower end of the middle pipe and the outer pipe is constituted by a rotary shaft body, which is a triple pipe of an inner pipe, a middle pipe, and an outer pipe, each of which can be changed in an arbitrary rotation direction and number of revolutions by a prime mover installed on the upper portion. Is made shorter than the inner pipe, the lower end of the inner pipe serves as the lower discharge port of the slurry-like curing agent, and a lower stage excavating and stirring blade is attached to the lower end of the inner pipe, and the lower end of the middle pipe is attached. Is equipped with an upper stirring blade, a spiral blade for earth removal is formed on the outer circumference of the outer tube, and an upper discharge port for the slurry-like hardening agent is provided at the lower end of the outer tube. A ground improvement device.