JPH09296441A - Continuous ground-improvement machine and method therefor using the machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously excavate a part of ground not to be improved and another part of ground to be improved, by a groundimprovement machine provided with an endless chain. SOLUTION: An endless chain 11 in which a cutting and agitating blade 13 is protruded at a section where a cutterpost positioned at the front side of the advancing direction of a base machine 1 at least penetrates in the underground, is spread. And an endless chain 12 is spread, in which a cutting and agitating blade 13 is protruded at a part of the lower end side of the cutter post 4, in the section where a cutter post 4 positioned at the rear side of the advancing direction of the base machine 1, is penetrated in the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously improving soft ground for the purpose of constructing a foundation for supporting aboveground structures, measures against ground liquefaction during earthquakes, measures against reinforcement of existing structures, etc. The present invention relates to a continuous ground improvement machine for constructing a hollow portion in the upper layer of the ground improvement body when continuously constructing the ground improvement body in a wall shape, and a continuous ground improvement method using the same.

[0002]

2. Description of the Related Art A ground improvement body, which is a mixture of excavated soil and solidifying material, which is constructed as a foundation for supporting a ground structure, usually extends from the ground surface to the required depth in the depth direction. Although it is constructed continuously, it may not be necessary to improve the ground near the ground surface because of the foundation structure of aboveground structures.

In the stirring and mixing treatment method by rotating the excavating bit and the excavating rod having the stirring blade, it is possible to cope by performing the empty excavation in which the solidifying material is not injected in the upper layer section where the ground improvement is unnecessary. With a ground improvement machine in which an endless chain having cutting and stirring blades is stretched around the outer circumference of a cutter post, the ground is improved over the stretched section of the endless chain, and therefore it is not possible to dig underground.

Therefore, after construction by a ground improvement machine having an endless chain, it is necessary to excavate an unnecessary improvement body in the upper layer by using a breaker or the like, but it is substantially difficult to excavate because the improvement strength is high. However, it will result in delay of construction period and increase of construction cost. Moreover, it is uneconomical to improve the ground for a layer that does not require the ground improvement, because the material and construction loss is large.

From the above background, the present invention proposes a ground improvement machine having an endless chain and a construction method thereof capable of simultaneously constructing an empty excavation portion which does not improve the soil and an improvement portion under the ground.

[0006]

In the present invention, a base machine is provided with two cutter posts which are arranged in parallel in the traveling direction thereof to support the cutter post, and a part of the stirring / mixing cutter post located on the rear side in the traveling direction is located near the lower end. Endless chains are stretched only in the section of, and the ground is cut by the excavation cutter post located on the forward side in the traveling direction, and the cutting soil and solidified material are agitated and mixed by the agitation and mixing cutter post behind it. This makes it possible to construct a hollow part and an improved part at the same time.

At least a section of the excavating cutter post that penetrates into the ground is provided with an endless chain having a cutting and stirring blade protruding from the outer circumference thereof over the entire length of the section so as to be circulated freely. With respect to the stirring / mixing cutter post, an endless chain having cutting and stirring blades projecting from the outer circumference is circulated around a part of the section penetrating into the ground near the lower end of the cutter post.

The excavating cutter post cuts the ground with a cutting agitating blade along the section where the endless chain is stretched and extends from the ground surface to the lower end thereof. The stirring / mixing cutter post is a part of the ground near the lower end of the section cut by the excavation cutter post, and contains the cutting soil cut by the excavation cutter post and the solidified material injected or discharged into the ground. Stir and mix, leaving the cutting soil above the upper end of the endless chain as it is.

The solidifying material may be injected into the range of the section where the endless chain of the stirring / mixing cutter post is stretched or discharged from the cutter post. Therefore, the solidifying material may be injected separately from the stirring / mixing cutter post. In addition to being injected into the ground through a pipe, it is discharged through the inside of the stirring / mixing cutter post as described in claim 2. In this case, at least one discharge hole is formed in communication with the inside of the stirring / mixing cutter post at an arbitrary position in the section where the endless chain is stretched.

The cutting soil that is agitated and mixed by the endless chain of the agitating and mixing cutter post is soil that can be agitated and mixed with the solidified material as it is by the endless chain of the excavating cutter post that has already been cut. The endless chain of the stirring and mixing cutter post is sufficient in size and shape to perform the functions of stirring and mixing.

The upper layer of the endless chain of the agitating / mixing cutter post is in the state where the endless chain of the excavating cutter post has been cut, as in the case of empty digging, or the drilling fluid and cutting soil such as fresh water or muddy water which is injected into the cutting soil during cutting. Since the soil remains mixed and mixed, root cutting near the ground surface, which is carried out for the construction of aboveground structures after the ground improvement work, can be easily performed, and the construction period can be shortened. In addition, there is no loss of materials and construction because the ground is not improved for the layers that do not require ground improvement.

Since the bearing capacity of the hollow excavation portion is disturbed by the cutting and stirring blades of the cutting post for excavation, or is agitated and mixed with muddy water or the like, the supporting force becomes small. While running, there is a risk of falling or sinking, but in the present invention, the empty excavation part is poorly improved by adjusting the interval between the cutting and stirring blades of each endless chain of the excavation cutter post and the stirring and mixing cutter post. With the poor improvement, it becomes possible to provide the ground above the improved portion with sufficient strength to support the construction machine.

The solidifying material discharged from the stirring / mixing cutter post side can be adjusted by adjusting the distance between the cutting / stirring blade of the endless chain of the excavating cutter post and the cutting / stirring blade of the endless chain of the stirring / mixing cutter post. Part of the digging wraps around the excavating cutter post, and the endless chain of the digging cutter post spreads across the ends of the digging cutter post. A poorly-improved portion having a bearing capacity is formed on an upper layer of the improved portion that is ground-improved by the post.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is, as shown in FIG. 1, a base machine 1, and a cutting post 3 for excavation and a cutter post for stirring and mixing which are supported by the base machine 1 in parallel in the traveling direction thereof. 4 is a ground improvement machine which continuously improves the ground in a part of the section near the lower end while digging the ground near the upper ends of the cutter posts 3 and 4.

The ground improvement machine is mainly used for constructing the foundation of a structure by improving the ground of soft ground, but the ground improvement body is continuously connected like a wall to prevent liquefaction of the ground at the time of an earthquake and reinforcement of existing structures. It is used for the purpose of leaving an empty trench in the general construction method.

As shown in FIG. 1 and FIG. 2 which is a side view thereof, a frame 5 is supported on the upper turning portion 2 of the base machine 1. A hydraulic jack 7 for preventing the base machine 1 from sinking and the frame 4 from being deformed due to a dynamic load during construction is connected under the upper turning portion 2 and under the frame 4.

The frame 5 is supported by the upper swivel unit 2 so that the angle of the frame 5 can be adjusted with respect to the vertical plane by being connected to a support member 8 extending from the upper swivel unit 2 and a stretchable stay 9 via a hinge. The posts 3 and 4 are supported not only in the vertical direction but also in a direction inclined with respect to the vertical direction.

A sliding member 10 for sliding the cutter posts 3 and 4 along the frame 5 while supporting the cutter posts 3 and 4 is reciprocally attached to the frame 5 in the longitudinal direction of the horizontal frame 6.

The sliding member 10 is forcibly moved by the hydraulic machine (not shown) through the frame 5 by using the base machine 1 as a reaction force to move the cutter posts 3 and 4 straight along the frame 5.

Endless chains 11 and 12 having cutting and stirring blades 13 are laid around the outer circumferences of the cutter posts 3 and 4 in a freely circulating manner. The endless chain 11 is between the sprockets 14 and 14 pivotally supported by the excavating cutter post 3, and the endless chain 12 is at the sprockets 15 pivotally supported by the agitating and mixing cutter post 4.
It is passed between 15 minutes. Each sprocket 14, 15 for circulating the endless chains 11, 12 is driven by a drive device 16 supported by the sliding member 10, respectively.

Of the parallel cutter posts 3 and 4, the endless chain 11 of the excavating cutter post 3 located on the front side in the traveling direction of the base machine 1 cuts the ground over the entire length of the cutter post 3 and moves to the rear side. The endless chain 12 of the positioned agitating and mixing cutter post 4 continuously improves the ground between its two ends.

The endless chain 12 of the agitating and mixing cutter post 4 is stretched over a part of the section of the cutter post 4 which penetrates into the ground, near the lower end of the cutter post 4.
The agitating and mixing cutter post 4 has sprocket wheels 14, 14 axially supported at its lower end position and an intermediate position in the longitudinal direction, and the endless chain 12 is stretched between the sprocket wheels 14, 14 in a freely circulating manner.

The sprocket 14 axially supported by the agitating / mixing cutter post 4 is in the form of overhanging in the width direction of the cutter post 4 as shown in FIG. 4, in order to prevent the endless chain 12 from interfering with the main body of the cutter post 4. The cutter post 4 is axially supported so as to be incorporated in the middle portion in the width direction.

The endless chain 12 of the stirring / mixing cutter post 4 stirs and mixes the cutting material cut by the endless chain 11 of the excavating cutter post 3 and the solidified material, but the endless chain
The cutting and stirring blade 13 projecting from the projection 12 is projected in two directions, that is, the advancing direction and the width direction of the cutter post 4, as shown in FIGS. To be done.

Endless chain 11 of cutter post 3 for excavation
In order to cut the unexcavated ground, a cutting and stirring blade 13 is provided so as to project over the entire width of the cutter post 3 as shown in FIGS.

5 and 6, the cutting and stirring blade 13 of the endless chain 12 is not formed so as to be continuous with the entire width of the stirring and mixing cutter post 4, but the cutting soil around the cutting and stirring blade 13 is not formed. Since the cutting post 3 for cutting has already fluidized, it flows into both sides in the width direction of the stirring / mixing cutter post 4 as shown by the arrow in FIG. The cutting and stirring blade 13 allows good stirring and mixing.

The solidifying material can be injected into the cutting soil from the side where the endless chain 12 descends through the outside of the stirring / mixing cutter post 4, but when discharging through the inside of the stirring / mixing cutter post 4, the cutter is used. Discharge holes communicating with the inside of the cutter post 4 are formed at one position or at a plurality of positions in the section of the upper sprocket 15 and the lower sprocket 15 of the post 4. A ground improvement machine in which a discharge hole is formed in the stirring / mixing cutter post 4 corresponds to the invention of claim 2.

The invention according to claim 3 uses the continuous ground improvement machine according to claim 1 or claim 2, wherein the cutter posts 3 and 4 arranged in parallel are connected to the endless chains 11 and 12 of both cutter posts 3 and 4. By moving while circulating,
This is a method in which a part of the layer close to the ground surface is dug without ground improvement, and the ground beneath it is continuously improved as shown in.

As described above, the construction is performed by cutting the ground from the ground surface to the lower end of the excavating cutter post 3 with the endless chain 11 of the excavating cutter post 3 and, at the rear thereof, the endless chain 12 of the stirring / mixing cutter post 4. Thus, the cutting soil and the solidified material are agitated and mixed over the stretched section. Cutter post for excavation 3
On the side, drilling is performed while pouring or discharging a drilling fluid such as fresh water or muddy water as necessary to prevent the collapse of the hole wall.

In FIG. 7, the distance between the cutting and stirring blade 13 of the excavating cutter post 3 and the cutting and stirring blade 13 of the stirring and mixing cutter post 4 is adjusted, and the mixture is discharged or injected from the side of the stirring and mixing cutter post 4. Utilizing the circulation of the endless chains 11 and 12, the solidifying material is made to wrap around to the excavating cutter post 3 side, and is spread over the section from the ground surface to the lower end of the cutter post 3 in the upper layer of the improved part, It shows a state in which a poorly-improved portion having a supporting force is formed.

Cutting and stirring blades 13 of each cutter post 3, 4
The distance between the blades 13 is adjusted not only by adjusting the distance between the cutter posts 3 and 4, but also by adjusting the protruding length of the cutting and stirring blade 13 from the endless chains 11 and 12.

Since the endless chains 11 and 12 circulate between their both ends, the solidifying material can be spread to both ends of the endless chain 11 regardless of the direction of circulation, so that the endless chains 11 and 12 can be The direction of circulation is not limited to FIG.

[0033]

According to the first and second aspects of the present invention, the base machine is made to support two cutter posts in parallel with each other in the advancing direction, and the endless chain is provided only in a part of the rear side of the advancing direction toward the lower end. It is possible to stir and mix the cutting soil and the solidified material with the cutter post on the rear side while cutting the ground with the cutter post on the front side in the traveling direction. The ground improvement machine makes it possible to construct an empty excavation part and an improvement part at the same time.

The cutting soil that the endless chain of the agitating and mixing cutter post on the rear side agitates and mixes is the soil that the endless chain of the excavating cutter post on the front side has already cut and can be agitated and mixed with the solidified material as it is. Therefore, the endless chain of the agitating and mixing cutter post is sufficient in size and shape to perform the functions of agitating and mixing.

Since the upper layer of the endless chain of the agitating and mixing cutter post is left in the cut state of the endless chain of the excavating cutter post as in the case of blank excavation, the ground required for constructing the ground structure after the implementation of claim 3 Root cutting near the surface can be easily performed, and the construction period can be shortened.

Further, since the ground is not improved for the layer which does not require the ground improvement, there is no loss of material and construction.

Furthermore, by adjusting the distance between the cutting and stirring blades of the endless chains of the cutting post for stirring and the cutting post for stirring and mixing, it is possible to form a poorly improved portion in place of the hollow excavation portion. It is possible to prevent the danger that the construction machine will fall or sink due to running of the construction machine.

[Brief description of drawings]

FIG. 1 is an elevational view showing a ground improvement machine.

FIG. 2 is a partial cross-sectional side view taken along the line xx of FIG.

FIG. 3 is a cross-sectional view of a cutting post for excavation.

4 is a partial cross-sectional side view taken along the line yy in FIG.

FIG. 5 is a cross-sectional view of a stirring / mixing cutter post.

FIG. 6 is an enlarged view of the cutter post shown in FIG.

FIG. 7 is an elevational view showing a state in which a poor improvement portion is formed instead of the hollow dug portion.

[Explanation of symbols]

1 ... Base machine, 2 ... Upper swivel part, 3 ... Cutter post for excavation, 4 ... Cutter post for stirring and mixing, 5
…… Frame, 6 …… Horizontal frame, 7 …… Hydraulic jack, 8…
… Supporting member, 9 …… Stay, 10 …… Sliding member, 11 …… Endless chain, 12 …… Endless chain, 13 …… Cutting and stirring blade,
14 ... sprocket, 15 ... sprocket, 16 ... drive device.

Claims (3)

[Claims] 1. A ground improvement machine in which two cutter posts are supported in parallel with each other in a traveling direction of a base machine, and penetrates at least into the ground of a cutting post for excavation located on the front side in the traveling direction of the base machine. An endless chain with cutting and stirring blades protruding from the outer periphery is stretched over the entire length of the section in a freely circulating manner, and is placed in the ground of the stirring / mixing cutter post located on the rear side in the traveling direction of the base machine. A continuous ground improvement machine in which an endless chain with cutting and stirring blades protruding from the outer periphery is circulatory stretched around a part of the penetrating section near the lower end of the cutter post. 2. The stirring / mixing cutter post is formed with at least one discharge hole for discharging the solidifying material at an arbitrary position in a section where the endless chain is stretched so as to communicate with the inside thereof. Continuous ground improvement machine. 3. The continuous cutter post of the continuous ground improvement machine according to claim 1 or claim 2 is moved while circulating the endless chains of both cutter posts, and is located near the lower end of the stirring / mixing cutter post. This is a method of continuously improving the ground in the section of the section, in which the ground from the ground surface to the lower end of the excavation cutter post is cut with the endless chain of the excavation cutter post, and the extension is performed with the endless chain of the stirring / mixing cutter post. A continuous ground improvement method that stirs and mixes the cutting soil cut by the excavating cutter post and the solidified material injected or discharged into the ground over the section that is being bridged.