JPH09209355A - Improvement method for soft ground - Google Patents

Abstract

(57) [Abstract] [Problem] Even if there is an obstacle in the ground, if necessary, a hole is drilled in the ground to form a sand filling area for backfilling the sand to improve the ground. (EN) Provided is a technology capable of constructing a whole with uniform strength and adopting an efficient high-pressure injection type ground improvement method. SOLUTION: The ground is drilled, and the drilled hole is backfilled with sand to form a sand-filled portion 17, and a cement-based material is added to the sand-filled portion formed in the first step. A method for improving soft ground including a second step of mixing and agitating a solidifying material, wherein in the first step, a cylindrical casing 11 is pressed into the ground by using a boring machine 10 and ground. It includes a step of making a hole and then pulling out the casing while backfilling the drilled hole with sand. In the second step, the stirring blade is rotated while high-pressure jetting air and solidifying material from the tip of the stirring blade 4. While including the process using the processor 2 for pulling out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving a soft ground formed by, for example, land reclamation work.

[0002]

2. Description of the Related Art Generally, the ground constructed by landfill construction has a weak bearing capacity, and is generally liquified by an earthquake. Therefore, for such ground, the ground is improved as necessary.

As the ground improvement technique, various methods have been conventionally known, and one of them is a high-pressure jet stirring method. In this method, a cement-based slurry-like solidifying material is mixed into the ground by an injection method and stirred, and is performed, for example, in the procedure shown in FIGS. 10 (A) to (G).

First, as shown in FIGS. 10 (A) and 10 (B), the processor 2 set on the ground 1 to be improved is treated with a solidifying material (slurry) from below the stirring shaft 3 to near the stirring blades. While discharging, it penetrates while stirring with the original ground soil. Then, as shown in FIG. 10 (C), when the predetermined depth is reached, after the tip treatment is performed, the air and the solidifying material are jetted from the tip of the stirring blade 4 to the high pressure sideward, and Start withdrawal. At the time of withdrawing the processing machine 2, the stirring blade 4 is withdrawn while ejecting a high-pressure jet stream.
At that time, the ground improvement area can be changed by injecting the jet at an arbitrary depth and changing the diameter (FIG. 10).
(F)). By the completion of the withdrawal of the processing machine 2, FIG.
As shown in 0 (G), the construction at that point is completed, and the processor 2 is moved to the next improvement point.

[0005]

By the way, when the ground is improved by using the high-pressure injection type agitation processing machine as described above, it is surely easier than the conventional individual mechanical agitation method and injection method. Moreover, a soil cement block for ground improvement can be formed in the ground quickly and economically. However, this method often causes problems when there are obstacles in the ground. For example, in a landfill,
In many cases, large reinforced concrete souls and rocks are contained in the landfill, which becomes obstacles in the ground to be improved. That is, the presence of the obstacle may prevent the processing machine from penetrating in the middle of the process. Therefore, it is necessary to remove such obstacles, but when the obstacles themselves exist at a deep place in the ground, it becomes extremely difficult work.

The present invention has been made in consideration of the above points. Even when there are obstacles in the ground, holes are bored in the obstacles as necessary to refill the sand with a sand filling portion. It is an object of the present invention to provide a technique capable of forming a whole ground to be improved with uniform strength by forming it, and adopting an efficient high-pressure injection type ground improvement method.

[0007]

In order to solve the above-mentioned problems, in the present invention, a first step of forming a sand filling portion by boring a hole in the ground and backfilling the boring hole with sand First
And a second step of mixing a cement-based solidifying material with the sand-filled portion formed in the step of mixing and stirring the same, wherein the first step is a cylinder using a boring machine. -Like casing is punched while being pressed into the ground, and then the casing is pulled out while backfilling the drilled hole with sand. In the second step, air and solidifying material are passed from the tip of the stirring blade. It was an improved method for soft ground, including the step of using a treatment machine for injecting high pressure jets while rotating a stirring blade. By adopting this construction method, if there are obstacles in the ground, by performing the first step and then the second step, the entire ground to be improved will be produced by the high-pressure injection method. The ground can be improved uniformly and efficiently.

In the first step, if there is a large obstacle such as boulders or concrete in the ground to be drilled, a core tube having a blade capable of excavating the obstacle at its tip end. It is highly preferable to insert the above into the casing for drilling. By doing so, even if the obstacle is located at a deep place, it can be easily drilled and removed.

In this case, it is preferable to adopt a method in which the core tube is drilled to a predetermined depth and then the casing is inserted. This is because drilling holes in the obstacle facilitates excavation of the obstacle by the casing when the casing is inserted. Therefore, the obstacle can be excavated by the casing while inserting the casing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying FIGS. Among them, FIG. 1 is a side view of a hole drilling machine suitable for use when carrying out the method for improving soft ground according to the present invention, FIG. 2 is a perspective view of a casing, and FIG. 3 is a perspective view of a core tube. 4 to 6 are process drawings showing a construction procedure, FIG. 7 is a flow chart showing a drilling procedure, FIG. 8 is a flow chart showing a backfilling procedure, and FIG. 9 is a sectional view showing a drilling procedure.

In the method for improving soft ground according to this embodiment, a hole is drilled in the ground by using a boring machine 10 as shown in FIG. 1, and the drilled hole is backfilled with sand to fill a sand filling portion. A first step of forming and a sand-filled portion formed in the first step are mixed with a cement-based solidifying material using a high-pressure injection type processor 2 as shown in FIG. 10 and stirred. Step 2 is performed.

The hole drilling machine 10 has a strong cutting force, and by combining it with a hole drilling tool suitable for the ground, it is possible to drill holes in hard ground such as cobblestone and rock and to remove underground reinforced concrete materials. Yes, the main body 10a, the support mast 10b, the rotating shaft 10c, the auger drill 10d, a casing tube (hereinafter referred to as a casing) 11 penetrating into the ground 1 as shown in FIG. 2, a core tube 12 shown in FIG. Prepare The casing 11 is formed thick and is provided with a digging blade 11a at its tip. Core tube 1
The reference numeral 2 is used by inserting it into the casing, and is formed to be thin and has a cutting blade 12 having a sharp cutting edge.
The penetration and the extraction of the casing 11 into the ground 1 are performed by the rotary head 13 of the hole drilling machine 10, the rocking machine, or the like.

In the first step, the boring machine 10 having such a function is used, and the boring machine 10 is installed at a position where the ground should be improved, as shown in FIG. 4 (A). Next, FIG.
As shown in (B), the casings 11 are sequentially connected and pressed into the ground 1 while rotating. Next, as shown in FIG. 5 (A), the casing 1 is removed by the auger drill 10d.
While excavating the inside of 1, remove the earth and sand inside.

Here, as shown in FIG. 5B, the ground 1
There are obstacles S such as boulders and concrete souls, so that the casing 11 is press-fitted or the auger drill 1
If there is a problem with drilling due to 0d, core tube 1
2 is used for drilling, and the core generated by the drilling is taken out. At this time, at a place where there is groundwater, as shown in FIG. 6 (A), the bucket 15 is used to make a hole. After drilling to a predetermined depth in this way, as shown in FIG. 6B, sand is backfilled in the drilled hole using a backhoe 16, for example, to form a sand filling portion 17. By moving the above process to another place and repeating, the sand filling part 17 is formed in the target ground improvement area.

In the first step using the boring machine 10, when there is an obstacle S in the ground 1 and it is difficult to press-fit the casing 11, as shown in FIG. A method may be adopted in which the core tube 12 inserted into the hole 11 is drilled until it passes through the region of the obstacle S, and then the casing 11 is press-fitted while the obstacle S is cut by the excavating blade 11a of the casing 11. Good. By doing so, even if the obstacle S is a reinforced concrete soul, since the through hole S1 is vacant there, the obstacle S is partially crushed or cut by the casing 11 while collapsing into the through hole. It is possible to cause a phenomenon such as falling to the S1 portion. Thereby, the press-fitting in the obstacle region of the casing 11 can be performed easily and continuously. That is, in the press-fitting of the casing 11, since the casing 11 is formed to be thick, the cutting ability is low by itself, but the through-hole S1 is opened first to substantially reduce the cutting ability of the casing 11. Can be increased to

Such a work procedure is shown as a flow chart in FIGS. 7 and 8. FIG. 7 showing a drilling procedure
In (2), if the underground obstacle cannot be removed with an auger, bucket, etc., core tube drilling work is incorporated to take out the core. If the result of measuring the drilled hole is good (Yes), the drilling is completed and the drilling work of the next point is started. Further, in FIG. 8 showing the backfilling procedure, backfilling is performed by alternately repeating backfilling work with the backhoe and casing withdrawing work.

After the first step is completed according to the above work procedure, the second step is then carried out using the jet type processor 2. The second step is a step of performing a work of extracting the air and the solidifying material while rotating the agitating blade while injecting the air and the solidifying material at a high pressure from the tip of the agitating blade. That is, in the second step, the processor 2 set on the ground (sand filling part) as shown in FIG. 10 is discharged from the lower end of the stirring shaft 3 while the solidifying material (slurry) is discharged. Penetrate while stirring with the ground soil. Then, after reaching the predetermined depth, after the tip processing is performed, air and high-pressure solidifying material are jetted from the tip of the stirring blade 4, and the withdrawal of the processor 2 is started. At the time of withdrawing the processing machine 2, the stirring blade 4 is withdrawn while ejecting a high-pressure jet stream. After the processing machine 2 is completely pulled out, the processing machine 2 is moved to the next point and the same work as above is performed. By repeating this, the ground improvement work in the necessary area is completed.

The ground improved in this way is a ground in which the sand-filled portion is hardened with a cement-based solidifying material, so that the ground has sufficient bearing capacity. In addition, even if there is an obstacle in the ground, it can be drilled and the sand is backfilled to form a sand-filled portion, so that the entire ground to be improved can be constructed with uniform strength, and efficiency is improved. A good high-pressure injection type ground improvement method can be implemented.

When a method using both mechanical stirring and high-pressure injection as shown in FIG. 10 is adopted, an improved body having a large cross section can be formed at once, but such a biaxial type stirring is used. The method is not limited, and a uniaxial type stirring method may be adopted. In that case, instead of the processing machine 2, the hole drilling machine 10 can be used to perform the first step and the second step. For example, the tip agitating portion including the agitating shaft 3 and the agitating blades 4 of the processor 2 may be replaced by
It has a removable structure instead of the 0 auger.
In the step (1), it is possible to attach the tip stirring portion to the boring machine 10 so that an improved body can be formed.

Further, in the above embodiment, the sand filling portion 17 is sequentially formed by using the boring machine 10. However, in the area where the ground can be directly improved by the processing machine 20, this is done, and the obstacle is obstructed. The present invention may be applied only to a region where an object exists. Further, for the sand filling portion 17, general earth and sand or other ground replacement material can be used as required.

[0021]

As described above, according to the present invention, the first step of forming a sand-filled portion by drilling holes in the ground and backfilling the drilled holes with sand, and the first step thereof A method for improving soft ground including a second step of mixing a cement-based solidifying material with the sand-filled portion formed in 1. and stirring the mixture, wherein in the first step, a cylindrical boring machine is used. It includes a step of punching the casing while press-fitting the casing into the ground, and then withdrawing the casing while backfilling the punched hole with sand. In the second step, the air and the solidifying material are pressurized to a high pressure from the tip of the stirring blade. It includes a step of using a processing machine for extracting while rotating the stirring blade while jetting. Therefore, when there is an obstacle in the ground, by performing the first step and then the second step, the whole ground to be improved is uniformly and efficiently by the high-pressure jet stirring method. The ground can be improved.

Further, by inserting a core tube having a blade capable of excavating an obstacle into the casing to make a hole, the hole can be easily made even when the obstacle is located deep. Can be removed. In that case, by adopting a method in which the casing is inserted after drilling a predetermined depth with the core tube, it is possible to facilitate excavation of an obstacle by the casing when the casing is inserted.

[Brief description of drawings]

FIG. 1 is a side view of a hole drilling machine suitable for an improved construction method according to the present invention.

FIG. 2 is a perspective view of a casing.

FIG. 3 is a perspective view of a core tube.

FIG. 4 is a process diagram showing a construction procedure.

FIG. 5 is a process diagram showing a construction procedure.

FIG. 6 is a process diagram showing a construction procedure.

FIG. 7 is a flowchart showing a drilling procedure.

FIG. 8 is a flowchart showing a backfill procedure.

FIG. 9 is a cross-sectional view showing a drilling procedure.

FIG. 10 is a process diagram showing a construction procedure by a high-pressure injection type stirring processor.

[Explanation of symbols]

 1 Ground 2 Processor 3 Stirring Shaft 4 Stirring Blade 10 Drilling Machine 11 Casing 12 Core Tube S Obstacle S1 Through Hole

Claims (4)

[Claims] 1. A first step of forming a sand-filled portion by drilling the ground and backfilling the drilled hole with sand, and a cement-based material for the sand-filled portion formed in the first step. A method for improving soft ground including a second step of mixing and stirring a solidifying material, wherein in the first step, a cylindrical casing is pressed into the ground by using a hole drilling machine. Then, including the step of pulling out the casing while backfilling the drilled hole with sand, in the second step, while rotating the stirring blade while injecting high pressure air and solidifying material from the tip of the stirring blade. A method for improving soft ground, characterized by including a step of using a processing machine for pulling out. 2. In the first step, when there are obstacles such as boulders and concrete in the ground to be drilled,
The method for improving soft ground according to claim 1, wherein a core tube having a blade capable of excavating the obstacle at its tip is inserted into the casing for drilling. 3. The method for improving soft ground according to claim 2, wherein the casing is inserted after drilling a predetermined depth by the core tube. 4. The method for improving soft ground according to claim 3, wherein the obstacle is excavated by the casing while press-fitting the casing.