JP2000290991A - Soil improvement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately from a soil improvement element in soil while restraining the discharge of slime. SOLUTION: A communicated first nozzle 50, a second nozzle 52 concentric with the first nozzle 52, a third nozzle 56 located upstream from the first and second nozzles 50, 52, and a fourth nozzle 58 located further upstream from them are formed at the end of a rod member 12. A soil is excavated by insertion of the rod member 12 into the ground, and after the rod member 12 is inserted to a predetermined depth, the A- and B-liquids of a quick-setting material are ejected respectively from the first and second nozzles 50, 52. Also, as clean water at a predetermined pressure is ejected from the third nozzle 56, the rod member 12 is rotated and gradually drawn back to construct a soil improvement element containing the setting material in a predetermined area under the ground. Clean water is ejected from the fourth nozzle 56 in such a manner that the range of the clean water ejected is smaller than the range of the clean water ejected by the third nozzle 56 to form a curtain of clean water in a gap between the rod member 12 and ambient soil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement method, and more particularly to a ground improvement method capable of forming an improved body in soil by a jet grout method.

[0002]

2. Description of the Related Art Water glass and cement milk are injected under high pressure in order to improve soft ground and to form a support layer and a water blocking layer in the ground, and a columnar ground improvement body having a predetermined radius (hardened layer). And a method of injecting these at a high pressure by using a two-component hardening material having an instantaneous setting has been used.
As an example of using a two-component hardening material with quick setting, see Japanese Patent Publication No. 7-5
In Japanese Patent No. 6133, a first nozzle provided on a tip side wall of a rod, a second nozzle and a third nozzle arranged concentrically downstream of the first nozzle are formed,
After the rod is inserted into the ground by a predetermined distance, fresh water is supplied from the first nozzle, liquid A of the two-component flash-setting material from the second nozzle, and two-liquid flash-setting material from the third nozzle. A technique is disclosed in which the liquid B is ejected and the rod is pulled back while rotating, thereby forming a ground improvement body having a predetermined radius. In this technique, an area where an improved body made of a hardening material is to be formed by fresh water sprayed from a first nozzle prior to ejection of the hardening material, and then a flashing hardening material is added to the spray mark. Is injected, whereby a more complete consolidation effect can be obtained due to the enhanced stirring and mixing effect.

[0003]

On the other hand, in recent years, with the construction of such ground improvement bodies, treatment of sludge discharged to the ground has become a major social problem. That is, even in the conventional method of injecting water glass and cement milk, or in the method of injecting a two-component quick-setting hardening material, the slime containing the hardening material passes through the gap between the rod and the ground. Released to the ground. Such slime becomes industrial waste, and its disposal requires enormous costs. In particular, slime containing a hardening material solidifies, so that the treatment itself is not easy.

[0004] Therefore, it is desirable to construct a ground improvement body in soil while suppressing slime emission itself. Therefore, an object of the present invention is to provide a ground improvement method capable of appropriately forming a ground improvement body in soil while suppressing slime discharge.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rod member having one or more flow paths therein and having at one end one or more nozzles communicating with the flow paths. After excavating the ground by inserting and inserting the rod member to a predetermined depth, while injecting a hardening material from any nozzle, gradually pulling back while rotating the rod member, a predetermined area in the ground A soil improvement method for creating a ground improvement body containing a hardening material, wherein the rod member is disposed upstream of the one or more nozzles,
And another nozzle connected to the flow path of fresh water is formed,
When the rod member is pulled back, fresh water is injected from the other nozzle to form a curtain of fresh water in a gap between the rod member and surrounding soil, and the ground is characterized in that Achieved by an improved construction method. According to the present invention, since a curtain is formed by fresh water injected from another nozzle, slime including soil cut by a hardening material or the like injected from a nozzle downstream therefrom is located upstream of the curtain. Movement is suppressed. Therefore, it is possible to construct a ground improvement body made of a hardening material or the like in a predetermined area in the ground while suppressing the amount of slime discharged to the ground.

In another embodiment of the present invention, at least two or more flow paths are provided therein, and at one end, at least one or more first nozzle groups communicating with one or more first flow path groups. And excavating the ground by inserting a rod member having a second nozzle formed upstream of the first nozzle group and communicating with the second flow path, into the ground,
After inserting the rod member to a predetermined depth, the hardening material supplied through the first channel group is ejected from the first nozzle group, and the predetermined material supplied through the second channel is supplied. The ground improvement method for forming a ground improvement body containing a hardening material in a predetermined area in the ground by gradually pulling back while rotating the rod member while injecting fresh water having a pressure of Another nozzle that is disposed upstream of the second nozzle and communicates with the second flow path, such that the reach of fresh water by injection is smaller than that of the second nozzle. By using the rod member formed with the nozzle, when the rod member is pulled back, the second nozzle and the other nozzles are also sprayed with fresh water to thereby provide a gap between the rod member and the surrounding soil. A curtain of Shimizu is formed in It is configured to. According to the present embodiment, the water cutting is performed by the fresh water injected from the second nozzle, the surrounding soil is cut, and the slime is generated. However, the slime is generated from other nozzles on the upstream side of the second nozzle. The space between the rod and the surrounding soil is substantially blocked by the curtain of the sprayed fresh water. Therefore, it is possible to suppress the slime from moving beyond the curtain.

In a preferred embodiment of the present invention, the first nozzle group includes a nozzle communicating with a first flow path,
A nozzle communicating with the second flow path;
Liquid A and liquid B of the liquid flash hardening material are supplied. Alternatively, the first nozzle group may include a nozzle communicating with a first flow path and a nozzle communicating with a second flow path, and water glass and cement milk may be supplied to each of the nozzle groups. In another embodiment of the present invention, a compressed air nozzle is formed around the second nozzle concentrically with the second nozzle and communicates with a flow path for passing compressed air. Fresh water is injected from the second nozzle and compressed air is injected from the compressed air nozzle.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing an apparatus for implementing a ground improvement method according to a first embodiment of the present invention. As shown in FIG. 1, a ground improvement device 10 includes a rod portion 12 and a boring machine 1.
4 is provided. The rod portion 12 is disposed at the lowermost portion (the most downstream portion) and has a blade pit for cutting soil and a monitor 1 having a nozzle for spraying water or hardening material as needed.
6, the rod 18-1 sequentially connected from the monitor 16,
18-2,... 18-n and a swivel joint 20 arranged at the uppermost portion (upstreammost portion). The rod 18 and the monitor 16 have a first path 21 for communicating the liquid A of the two-component flash hardening material and a second path 21 for communicating the liquid B of the two-liquid flash hardening material. And a third path 25 for communicating fresh water, and a flow path communicating with each other.

The first passage 21 is connected to a high-pressure pump 22, and the high-pressure pump 22 is connected to a first hardening material tank 28 containing the liquid A. The second path 23 is connected to a high-pressure pump 24, and the high-pressure pump 24 is connected to a second hardening material tank 30 containing the B liquid. Further, the third path 25 is connected to a high-pressure pump 26. Shimizu 3 in the water tank 32
4 and the fresh water is supplied to the high-pressure pump 26.

[0010] As shown in FIG.
Is a chucking clamp 38 of the boring machine 14.
Raising / lowering the monitor 16 having a diameter (for example, φ60.5 mm) that can be chucked at (see FIG. 1), and stepping distance of the boring machine 14, that is, chucking in one stroke. (For example, 3 m). In addition, the monitor 16 includes a first channel 42 communicating with the first channel 21, a second channel 44 communicating with the second channel 23, and a third channel communicating with the third channel 25. Channel 4
6 is provided. At one end of the monitor 16, a blade pit 48 for cutting the soil is provided. FIG.
As shown in (a) and FIG. 2 (b), a first nozzle 50 for injecting the A liquid of the two-component instantaneous hardening material supplied from the first flow path 42 is provided slightly upstream from the tip. Are arranged and concentrically with this, supplied from the second flow path 44.
A second nozzle 52 for injecting the liquid B of the liquid flash hardening material is provided. Also, the first and second nozzles 50, 5
The third flow path 46 is located a predetermined distance upstream from the position 2.
Nozzle 56 for injecting the supplied fresh water in communication with
Is formed, and a third flow path 46 is also provided upstream thereof.
Nozzle 58 that communicates with and injects the supplied fresh water
Are formed. For example, the fourth nozzle 58 and the third nozzle 58
A flow control valve or the like for controlling the pressure of fresh water injected from the fourth nozzle 58 may be provided between the flow path 46 and the flow path 46.

As can be understood from FIG. 2B, in the present embodiment, the cross-sectional shape of the third nozzle 56 is 6
The fourth nozzle 58 has a polygonal shape such as a square shape, and the cross-sectional shape of the fourth nozzle 58 is rectangular or rectangular. Further, in the present embodiment, the diameter of the fourth nozzle 58 is smaller than that of the third nozzle 56. Of course, the cross-sectional shape of the nozzle is not limited to this, and the cross-sectional shape of the third nozzle 56 may be circular, or the fourth nozzle 5
The cross-sectional shape of 8 may be another polygonal or circular shape.
Further, in the present embodiment, the fourth nozzle 58 is formed 50 cm to 1 m upstream of the third nozzle, but this distance is not limited to this and will be described in detail below. The curtain may be formed by the fresh water jetted from the fourth nozzle 58, and the position may be any position that suppresses the rise of the slime. The rod 18 also has a diameter (for example, φ6) that is chucked by the chuck 38 (see FIG. 1) of the boring machine 14.
0.5 mm) and has a length (for example, 3 m) substantially equal to the step distance of the boring machine 14. In addition, the rod 18 has the first to third paths 2
First to third flow paths (not shown) communicating with 1, 23 and 25 are provided.

The operation of the thus constructed ground improvement apparatus will be described below. First, the rod portion 12 to which the monitor 16 and the plurality of rods 18 are connected is inserted into the soil while rotating using the boring machine 14. The ground is excavated by the bit 48 formed at the tip of the monitor 16, whereby the rod portion 12 is gradually inserted into the ground. As shown in FIG. 3A, when the tip of the monitor 16 reaches a predetermined depth, the pumps 22, 24, and 26 are operated to operate the first to third flow paths 21, 23, and 25.
, A liquid A of a two-component flash hardening material, a liquid B of a two-pack flash hardening material, and fresh water, respectively. As a result, the first nozzle 50 shown in FIG. 2 ejects a two-component liquid of the instantaneous hardening material A, and the second nozzle 52 ejects a two-component liquid of the instantaneous curing material B.
Further, fresh water is injected from the third nozzle 56 and the fourth nozzle 58.

After the operation of the pump, as shown in FIG. 3B, the rod 12 is pulled upward while rotating.
Here, a predetermined pressure (for example, 20
By supplying fresh water at 0 to 500 kgf / cm ² ), fresh water is ejected from the third nozzle 56 and the fourth nozzle 58. As shown in FIG. 3B, as the rod portion 12 is pulled back by rotating the rod portion 12 by the fresh water ejected from the third nozzle 56, the soil (see reference numeral 301) in the area where the nozzle 56 has passed is jetted at a high pressure. The water is cut and the area is ordered. Next, a predetermined pressure (for example, 20 μm) is applied from the first nozzle 50 and the second nozzle 52 formed downstream of the third nozzle 56 to the region ordered by fresh water from the third nozzle 56.
0 to 500 kgf / cm ² ), the liquid A and liquid B of the instantaneous hardening material are jetted, and the instantaneous hardening material mixed in the jetting process is filled in the above-mentioned region, and the soil improvement body (reference numeral 30)
2) is formed.

As described above, in the present embodiment, the third flow path 25 is provided upstream of the third nozzle 56.
A fourth nozzle 58 communicating with the nozzle is formed. Therefore, when fresh water is supplied to the third flow path 25 at a predetermined pressure, fresh water is ejected from the third nozzle 56 and also fresh water is ejected from the fourth nozzle 58.
In the present embodiment, as shown in FIG. 4, it reaches distance L ₁ Shimizu ejected from the third nozzle 56, Shimizu reach distances L ₂ sufficiently than ejected from the fourth nozzle 58 It is preferable that the pressure and the amount of the fluid ejected from the nozzle are adjusted so as to increase the pressure. For example,
For this purpose, as described above, the diameter of the fourth nozzle 58 is made smaller than that of the third nozzle 56, and the cross-sectional shape is adjusted. In addition, as described above, in order to adjust the flow rate of fresh water toward the fourth nozzle 58, a flow control valve (not shown) is provided in the third flow path 25 near the fourth nozzle 58. Needless to say, it is good. The reaching distance L of fresh water injected from the fourth nozzle 58
₂ is preferably slightly larger than the diameter of the hole drilled by the rod portion 12.

Now, the soil is pulverized by the fresh water injected from the third nozzle 56 at a high pressure, whereby, for example, the pulverized soil is formed above the area 301 shown in FIG. 3B. You can see that the slime is heading. In addition, the slime containing the hardening material also moves upward due to the instantaneous hardening material injected from the first and second nozzles 50 and 52. In this embodiment, the fourth nozzles 58, so that the reach distance is greater L ₂ than the diameter of the hole to be drilled by the rod portion 12, Shimizu is injected. Therefore, when the rod portion 12 rotates, the fresh water from the fourth nozzle 58 functions as a curtain, and suppresses the rise of the slime. That is, as shown in FIG. 5, slime 501 composed of soil pulverized by the fresh water “W” and slime mixed with the hardener “A + B” are formed by the fresh water injected from the fourth nozzle 52. The rise is suppressed by the curtain WC.
Therefore, unnecessary discharge of the slime to the ground surface is prevented. Further, by making the shape of the fourth nozzle 52 square or rectangular, a sufficient curtain effect can be obtained.

According to the present embodiment, as the rod portion 12 rises (pulls back) while rotating, fresh water spouted from the third nozzle 56 formed on the upstream side causes the surrounding soil to be removed. By the first nozzle 50 and the second nozzle 52 which are cut and formed on the downstream side, the liquid A and the liquid B of the instantaneously hardening material are jetted and mixed into a region ordered by drainage, and The ground improvement body containing the hardening material is formed in the region to be cured. On the other hand, fresh water is also ejected from the fourth nozzle 58 disposed on the most upstream side, which functions as a curtain, and slime is substantially prevented from rising above the curtain. Therefore, unnecessary discharge of slime to the ground surface can be prevented.

Next, a description will be given of a second embodiment of the present invention. In this embodiment, the present invention is applied to a ground improvement method called an RJS method.
FIG. 6 is a diagram schematically illustrating an apparatus for performing the ground improvement method according to the second embodiment. Similar to the first embodiment, the ground improvement device 10 includes a rod 112 and a boring machine 114. As in the first embodiment, the rod portion 112 is disposed at the lowermost portion (the most downstream portion) and has a blade pit for cutting the soil, and a monitor 116 having a nozzle for spraying water or hardening material as needed. , The rods 118-1 and 1-1 sequentially connected from the monitor 116.
18-2,... 118-n and a swivel joint 120 arranged at the uppermost part (upstream part). In this embodiment, the rod 118 and the monitor 116 also have a triple tube structure, and the three flow paths formed therein have a first path 121 for supplying a hardening material and a first path 121 for supplying compressed air. The second flow path 123 and the third path 125 for supplying water communicate with each other. Also, the diameter and length of the monitor 116 and the rod 118
This is the same as that of the first embodiment.

The first path 121 is connected to a grout mixer 140 via a high-pressure pump 122. The grout mixer 140 is supplied with a hardening material (cement milk) from a grout tank 142. The second path 123 is connected to a compressor 124, and the third path 125 is connected to a high-pressure pump 126. The high-pressure pump 126 is supplied with fresh water 134 from a tank 132.

As shown in FIG. 7, in the present embodiment, a first nozzle 150 communicating with the first flow path is disposed slightly upstream from the tip of the monitor 124, and
A second nozzle 152 communicating with the second flow path is disposed concentrically with the second nozzle. These nozzles 150, 15
A third nozzle 154 communicating with the third path and a fourth nozzle 156 concentric with the third nozzle 154 and communicating with the second flow path are arranged at a predetermined distance upstream of the second nozzle. Have been. Further, in the present embodiment, a fifth nozzle 158 communicating with the third flow path is formed upstream of the nozzles 154 and 156 by a predetermined distance. As in the first embodiment, the diameter of the fifth nozzle 158 is preferably smaller than that of the third nozzle 154, and the fifth nozzle 158 in the third flow path.
May be provided with a flow control valve for controlling the pressure of fresh water injected from the nozzle.

In the ground improvement apparatus thus configured, first, the rod portion 112 is connected to the boring machine 114.
Insert into the ground while rotating using. Thus, the ground is excavated by the bit 148 formed at the tip of the monitor 116. When the tip of the monitor 116 reaches a predetermined depth, the rod part 12 is pulled back upward while rotating, and the pump 122, the compressor 124, and the pump 126 are operated to operate the first to third flow paths 1.
21, 123, 125, respectively, cement milk,
Supply compressed air and fresh water. For example, cement milk is about 400 kgf / cm ² and compressed air is about 7 kgf.
/ Cm ² , and fresh water is supplied at a pressure of about 200 kgf / cm ² . As a result, as shown in FIG. 7, the hardening material CM is jetted from the first nozzle 150, and the compressed air AR is jetted from the surrounding second nozzle 152. Further, a third nozzle 154 formed on the upstream side thereof
Is sprayed from the nozzle, and the fourth nozzle 15
From 6, compressed air AR is injected.

Third nozzle 154 and fourth nozzle 1
With the fresh water and compressed air injected from 56, the surrounding soil is cut and ordered. Next, the cement milk injected from the first nozzle 150 is filled in the ordered area, and a soil improvement body (see reference numeral 702 in FIG. 7) is created. Also in the present embodiment, a fifth nozzle 158 for injecting fresh water is formed at a predetermined position on the upstream side of the third nozzle 154 and the fourth nozzle 156. The reach of fresh water from the nozzle may be sufficiently smaller than the reach of fresh water by a nozzle formed on the downstream side, as in the first embodiment. The curtain WC is formed by the fresh water injected from the fifth nozzle 158, and the slime (see reference numeral 701) containing the soil pulverized by the water cutting is blocked by the curtain and may rise upward. Is suppressed. Therefore, according to the present embodiment, it is possible to prevent slime from being discharged to the ground surface when the wings are needed.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. Needless to say, this is done. For example, in the first embodiment, the liquid A and the liquid B of the two-part final curing material are jetted from the first nozzle and the second nozzle formed concentrically. However, the present invention is not limited to this, and water glass and cement may be jetted from the first nozzle and the second nozzle. In this case, the two nozzles do not necessarily have to be formed concentrically.

In the above embodiment, another nozzle communicating with the flow path of the fresh water is provided upstream of the nozzle for cutting with the fresh water, and a curtain is formed by the fresh water jetted from the nozzle. , But is not limited to this. For example, a separate fresh water flow path may be provided, and fresh water supplied through the flow path may be jetted from a nozzle to form a curtain.

Further, although the present invention is applied to a device that performs cutting with fresh water (so-called draining) when pulling up the rod portion, the present invention may be applied to a device that performs pre-cut when inserting the rod portion. In this case, it is not possible to effectively prevent the discharge of the slime generated when the rod is inserted, but it is possible to suppress the discharge of the slime mixed with the hardening material when the rod is pulled up.

In the above-described embodiment, the rod member is inserted vertically into the ground. However, the present invention is not limited to this. The rod member may be inserted horizontally or diagonally into the ground. The present invention can be applied to a method of inserting a member. Further, in this specification, the function of one member may be realized by two or more physical members, or the function of two or more members may be realized by one physical member.

[0026]

According to the present invention, it is possible to provide a ground improvement method capable of appropriately forming a ground improvement body in soil while suppressing slime discharge.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an apparatus for implementing a ground improvement method according to a first embodiment of the present invention.

FIG. 2 is a partial schematic cross-sectional view and a partial schematic front view of the monitor according to the first embodiment.

FIG. 3 is a diagram illustrating a procedure of a ground improvement method according to the first embodiment.

FIG. 4 is a diagram illustrating arrival of fresh water jetted from a second nozzle and a third nozzle according to the first embodiment.

FIG. 5 is a diagram for explaining a procedure of a ground improvement method according to the first embodiment.

FIG. 6 is a view schematically showing an apparatus for implementing a ground improvement method according to a second embodiment of the present invention.

FIG. 7 is a diagram for explaining ground cutting by a monitor according to the second embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ground improvement apparatus 12 Rod part 14 Boring machine 16 Monitor 18 Rod 20 Swivel joint 42 1st flow path 44 2nd flow path 46 3rd flow path 50 1st nozzle 52 2nd nozzle 56 3rd nozzle 58 4th nozzle

Claims (5)

[Claims] A ground is excavated by inserting under the ground a rod member having at least one flow path therein and having at least one nozzle formed at the tip thereof and communicating with the flow path. After the rod member is inserted to a depth of less than 1, the hardening material is ejected from any nozzle, and the rod member is gradually pulled back while rotating, thereby forming a ground improvement body containing the hardening material in a predetermined region in the ground. In the soil improvement method, the rod member is disposed upstream of the one or more nozzles, and another nozzle connected to the flow path of fresh water is formed, and when the rod member is pulled back, A ground improvement method, wherein fresh water is injected from the other nozzle to form a curtain of fresh water in a gap between the rod member and surrounding soil. 2. At least two or more flow paths therein, and at one end thereof, at least one or more first nozzle groups communicating with one or more first flow path groups, and a first nozzle group A second fluid passage disposed upstream of the second fluid passage and communicating with the second flow passage;
The ground is excavated by inserting the rod member having the nozzle formed therein into the ground, and after inserting the rod member to a predetermined depth, the hardened material supplied through the first channel group is subjected to the first flow. Injection from the nozzle group of, and, while injecting fresh water of a predetermined pressure supplied through the second flow path from the second nozzle, while rotating the rod member, gradually pulling back, underground A ground improvement method for forming a ground improvement body containing a hardening material in a predetermined region, wherein the rod member is disposed upstream of the second nozzle, and communicates with a second flow path. Another nozzle is formed, the other nozzle of which the reaching distance of fresh water by injection is smaller than that of the second nozzle, and the other nozzle together with the second nozzle when the rod member is pulled back. Spraying fresh water And by the rod member and the ground improvement method, characterized in that the gap Shimizu curtain is configured to be formed between the surrounding soil. 3. The first nozzle group includes a nozzle communicating with a first flow path and a nozzle communicating with a second flow path. The ground improvement method according to claim 2, wherein the liquid and the liquid B are supplied. 4. The first nozzle group has a nozzle communicating with a first flow path and a nozzle communicating with a second flow path, to which water glass and cement milk are supplied, respectively. The ground improvement method according to claim 2, wherein: 5. A compressed air nozzle is formed around the second nozzle concentrically with the second nozzle and communicates with a flow path for passing compressed air. 3. The ground improvement method according to claim 2, wherein fresh water is injected from the nozzle and compressed air is injected from the compressed air nozzle.