JP3426556B2 - Ground improvement device and ground improvement method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement device particularly suitable for construction work in which pipe materials such as water and sewer pipes and gas pipes are buried in the ground, and a construction method using the same. (EN) A ground improvement device and a construction method capable of extremely rapidly and accurately improving and solidifying the ground in a construction area.

[0002]

2. Description of the Related Art For example, FIG.
9 will be described. Although the figure shows a state in which the buried pipe P is installed in the pipe buried groove V already excavated,
In general, a large number of sheet piles A for earth retaining are placed on the ground surface GL at the construction site before excavating the pipe burying groove. in this case,
The distance between the rows of sheet piles that are driven in two rows on both sides corresponds to the width w of the pipe burying groove V that corresponds to the diameter of the buried pipe P. After finishing the driving of the row of piles, a drilling machine such as a backhoe is used. The earth and sand in the position corresponding to the pipe burial groove V are excavated and discharged by using the above. The cutting depth d of such a pipe embedding groove V is usually about 3 to 7 m in the case of a sewer pipe, for example.

Subsequently, these sheet pile rows are reinforced by using an abdomen B and a bevel C to secure a pipe burying groove V which is also a working space, and then a burying pipe supporting floor D is provided on the bottom surface of the pipe burying groove V. Is installed, and the buried pipe P is installed on it. And after installing the buried pipe, the sheet pile A, the uprising B, and the cut C
In addition to the removal work of the above, the backfilling of the buried groove with mountain sand and the like and the compaction work are performed.

In the generally known pipe burying method as described above, earth retaining work is usually required using steel sheet piles and the pipe burying groove V having a depth required for laying the pipe is required to be excavated and backfilled. In particular, in order to dispose of excavated soil and backfill with sand and sand, etc., in addition to an increase in the number of processes due to the transfer and disposal of excavated soil, collection and transfer of sand and sand, etc., the impact on the traffic environment and natural environment. Is a very big problem.

In addition to a long construction period due to an increase in the number of processes, construction costs are high and the burden on the surrounding living environment, traffic environment, etc. is large, especially for pipe burial work in urban areas. The burden on the government is serious. Therefore, as a burial construction method that solves such problems all at once, in particular, it eliminates the need for excavation work for a pipe burial groove that involves soil removal for burying a pipe, and reduces the amount of soil left as excavation soil to 1/3 that of the conventional method. ~ 1
A pipe burying method that reduces the amount to / 4 and does not generate sludge that becomes industrial waste has been proposed as a method that utilizes ground improvement. Then, as such a ground improvement method, while excavating the ground with a multi-axis auger, at the same time, a ground hardening agent is injected from the drilling head of the auger, and the hardening agent and the excavated soil are mixed and stirred by the drilling head and the stirring blade. By doing so, the soil curing agent is made into a slurry form, and the buried pipe is inserted when the slurry form is not cured.

[0006]

By the way, in the case of constructing a ground improvement work area of a constant width quickly and efficiently over a long distance, as in the case of a pipe burying work using the ground improvement as described above, it is usually The construction method using the multi-axis auger had problems such as a slow construction speed. Focusing on such a point, the present invention provides a ground improvement device and a ground improvement method capable of constructing a ground improvement area having a constant width and a relatively shallow depth over a long distance extremely quickly and efficiently.

[0007]

SUMMARY OF THE INVENTION The present invention is a ground improvement apparatus having a multi-axis auger portion that is vertically movable in a guide of a base machine, the multi-axis auger portion having a plurality of drive motors. A multi-axis auger part having a gear train for synchronously driving a large number of auger shafts by the motor
Is the central auger shaft and the eight auger shafts that surround it.
The central auger shaft has a large drilling head at the bottom.
And there are 4 auger shafts for medium-sized drilling heads in the middle
However, there are four small auger shafts on the upper stage.
However , each auger shaft has a drilling head capable of discharging a curing agent and a stirring blade, and it is possible to make a substantially rectangular arbitrary area portion into a soil curing agent slurry by a single drilling and stirring process. It is a ground improvement device. Also, many auger shafts
Using soil improvement equipment that has
It is a ground improvement method that is performed in the form of an agent slurry,
1 large drilling head in the middle of the tier and 4 medium-sized digs in the middle tier
A multi-axis machine consisting of a cutting head and four small drilling heads on the upper stage.
The rugger section allows one step to be performed over a constant rectangular area.
Reconstruction is performed, and such processes are sequentially performed adjacent to each other in a certain direction.
As a result, a narrow and narrow construction area can be quickly improved.
It is characterized by being able to work.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. First,
1 and 2 are a front view and a side view of a ground improvement device 10 according to the present invention. As shown in both figures, the ground improvement device 10 has a schematic base machine 11 and an auger section 20, and the base machine 11 generally has a base machine such as a well-known backhoe having a track 12 and the like. It has a similar structure and is a machine with good mobility and workability even on soft ground.

The operation portion main body 14, which is rotatable on the carriage portion 13 of the base machine 11, has an auger portion 20 at its tip, has a tilt adjusting function means 16, and has a guide 15 along the leader, along a chain. It shall have a device that can be raised and lowered by a wire or hydraulic cylinder raising and lowering means. Generally, the lifting stroke is preferably about 5 to 7 m. In addition, the structure of the base machine itself is well known,
For example, a vehicle such as a backhoe can be used, and therefore further description is omitted.

The auger unit 20 which can be moved up and down along the guide 15 has, for example, two drive motors M ₁ and M ₂ in this embodiment, and an auger shaft R _n which is a large number of excavation shafts driven thereby. Have In the gear box indicated by the reference numeral 21, for example, a gear train including a large number of gears G _n for transmitting the rotational torques of the _two motors M ₁ and M ₂ to a large number of auger shafts R _n described later is housed. Has been done.

Reference numeral 22 is a shaft support portion that rotatably supports the multi-auger shaft R _n, and the gear box 21.
With the shaft support portion 22, a large number of auger axes R _n are mounted and supported on the auger frame body 24. And the auger frame 2
4 by moving up and down with respect to the guide 15, or a motor including a gear box 21 with respect to the auger frame,
By moving the auger shaft up and down, excavation and ground improvement by the auger unit 20 at arbitrary positions becomes possible.

The auger section 20 of the ground improvement apparatus according to the present invention
The first feature is that the multiple auger axes R _n, So many
Gas head OH_nIs to have. And these many
With each of the number of auger heads having a drilling head,
The tip of each excavation head is equipped with a
An outlet for hardener such as mentor milk is provided.
Gas head OH_nRotation of the ground hardens at the same time as excavation of the ground
Inject agent and spiral blade OF_nMixed by stirring
It However, such an auger head itself or excavation
The mechanism of the head and the curing agent discharge is not specially new,
It is possible to use the ground improvement auger head of the known type.
Therefore, detailed description of these structures will be omitted.

FIGS. 3 to 8 show a first embodiment of the auger unit 20, particularly the drive unit. Figure 3
As is apparent from FIG. 4 and FIG. 4, this embodiment has _two motors M ₁ and M ₂ for rotational driving of the auger shaft, and each motor is fixed to the top plate of the gear box 21. In the case of such a drive mechanism, as shown in the cross section of the gear box 21 in FIG. 3, the motors M ₁ , M
Drive shafts DR ₁ , D which also serve as or are connected to the _two rotary shafts
R ₂ is connectable so that the gears G ₁ and G ₂ are fixed and the auger shafts R ₁ and R ₂ are directly driven.

The gears G ₁ and G ₂ fixed to the drive shafts DR ₁ and DR ₂ are fixed to the central drive shaft DR ₃ as will be apparent from FIG. 5, which is a sectional view taken along line A in FIG. The drive shaft DR ₃ is connected via a gear G _{3 so} as to rotate and drive, and the upper end of the central drive shaft DR ₃ is on the top plate of the gear box 21 and is a swivel bearing SW as shown in FIG. It is supported and its lower end is the central auger axis R
_It is connected to ₃ .

[0015] Figure 5 is a view illustrating the A section of Figure 3 as described above, as is apparent from the figure, the gear G ₃ a central drive shaft DR ₃ meshed with the gear G ₁ and G ₂
Further meshes with the gears G ₄ and G ₅ fixed to the other pair of drive shafts DR ₄ and DR ₅ in the same plane as these gears and in the central portion thereof. Therefore, as is clear from FIG. 5 which is a cross-section A of FIG. 3, the gears G _{1 to} G ₅ can rotate synchronously in the directions of the arrows shown in the figure as the motors M ₁ and M ₂ rotate.

Further, as is apparent from FIG. 3, the drive shaft DR connected to each of the rotary shafts of the motors M ₁ and M _2.
The central gear G ₃ by the respective gears G ₁ and G _{2 of 1} and DR _2.
The central drive shaft DR ₃ driven via the
_An upper central gear G ₁₀ is further fixed above the position ₃ .

As is clear from FIG. 6 which is a B cross section of FIG. 3, the pair of gears G ₁₁ and G _{12 respectively} meshing with the upper central gear G ₁₀ are as shown in FIGS. 6, 7 and 8, for example. Is fixed to the gear support shafts GR ₁₁ and GR ₁₂ , and each of the gears G ₁₁ and G ₁₂ is further meshed with a pair of gears G ₆ , G ₇ and G ₈ , G ₉ , respectively. Then, each of the drive shaft _DR 6 _{~DR 9} is fixed to the gear _G 6 ~G _9, 4 both its upper end
It is supported on the upper plate of the gear box 21 by the swivel bearing SW shown in FIG.

As is apparent from FIGS. 6 to 8, a pair of shaft supporting brackets B ₁ and B ₂ are provided on the side surfaces of the gear box 21.
And the brackets B ₁ and B ₂ are provided so as to project inward at approximately the middle stage of the gearbox, and
The upper bearing portion supports the lower ends of the gear support shafts GR ₁₁ and GR ₁₂ for the gears G ₁₁ and G ₁₂ described above. The upper ends of these gear support shafts are supported by the upper surface plate of the gear box 21 by a normal bearing as shown. Further, as is particularly clear from FIG. 8, the drive shaft DR shown in FIG. 5 is provided on the lower surface of the brackets B ₁ and B ₂ .
The upper ends of ₄ and DR ₅ are pivotally supported.

As described above, all the gears G _{1 to} G ₁₂ are synchronously engaged in the gear box 21, and
These respective gears rotate integrally with the motors M ₁ and M ₂ and drive shafts DR _{1 to} DR coupled to the respective gears G _{1 to} G _9.
9 is driven to rotate synchronously. The auger axes OR _{1 to} OR ₉ are detachably connected to the respective drive shafts as described above.

In FIG. 9, auger heads OH _{1 to} OH ₉ integrally provided on the auger axes OR _{1 to} OR ₉ are provided.
Are shown schematically. In this figure, the diameter of the circle of each auger head indicates the size of the excavating head of the embodiment, for example, the central auger head OH ₃ is Φ550, and the rectangular auger heads OH ₁ , OH ₂ , OH ₄ , and OH ₅ are Φ, respectively.
300, auger heads OH _{6 to} OH _{9 on} the central side surface are φ4
However, the number is not limited to this value. Further, the arrows in the figure indicate the rotation directions of the auger heads, and the diameters of the respective auger shafts are all unified, for example, Φ = 100 mm.

Although the structure of each of the auger heads OH _{1 to} OH ₉ shown in FIG. 9 is not specified, a conventionally known auger head for ground improvement as shown in FIG. 2 can be used. A spiral blade D for stirring and mixing the excavated soil and the injected curing agent is provided above each excavation head having the curing agent discharge port.
F _n is provided for each. When the auger head having the above-described dimensions is used, as is clear from FIG. 9, a substantially square area having a side of about 1000 mm can be constructed by one step of ground improvement process, and in particular, its construction width. 1000 mm is a sufficient width as a construction area for ground improvement work corresponding to the burial groove V for burying the conventional sewer pipe shown in FIG. 19, for example. Therefore, when the ground improvement work is performed using the ground improvement apparatus of the above-mentioned embodiment, it is possible to improve the area of about 1 m in width and about 1 m in length by one step of ground improvement, and by repeating this step. It enables extremely quick ground improvement.

Next, the structure of the driving device portion in the auger unit 20 according to the second embodiment will be described with reference to FIGS. 10 to 15. The same members as those in the first embodiment are designated by the same reference numerals. And explain. In this embodiment, FIG.
It has four motors M _{1 to} M ₄ as shown in FIG.
It is fixed to the upper part of the upper plate of the gear box 21 as in the embodiment described above. Each swivel bearing SW in the figure is for supporting the upper surface plate on the drive shaft DR _3, DR ₆ likewise gearbox 21 each axial end of ～DR ₉ which respectively described later.

FIG. 10 shows a gear box in the second embodiment.
The central portion of the box 21 is shown in cross section, and the motor M₁，
M_TwoDrive shafts DR that can be integrated with or connected to the rotary shaft of₁，
DR _TwoIs the auger axis R, which will be described later.₁, R_TwoConnected with
And these drive axes DR ₁, DR_TwoTeeth fixed to
Car G₁, G_TwoIs the central gear G_ThreeAnd the bottom of the gearbox 21
And the central gear G_ThreeStuck to
Drive axis DR_ThreeTo central auger axis R_ThreeAre connected
It

FIG. 12 shows the A cross section of FIG.
A part of the gearbox 21 is shown in FIG.
In the lower stage, four gears G ₁ , G ₂ , G ₄ , and G ₅ are eventually meshed with each other with the central gear G ₃ as the center. Then, the gear _G 1, _{G 2} which is fixed to the motor _M 1, the drive shaft is coupled to the or rotating shaft integral with this _{M 2 DR} 1, _{DR 2} as described above, the drive shaft _DR 1, DR ₂ is directly connected to the auger shafts R ₁ and R ₂ via another gear G.
₄ and G ₅ are fixed to the drive shafts DR ₄ and DR ₅ , respectively, and are further connected to the auger shafts R ₄ and R ₅ , and are not directly connected to the other motors M ₃ and M ₄ . That is, the motors M ₁ and M ₂ are configured to synchronously drive the gears G ₄ and G ₅ from the gears G ₁ and G ₂ via the central gear G ₃ .

FIG. 13 shows the B cross section of FIG. 10, in which gears G ₁₀ and G ₁₁ fixed to the rotating shafts MR ₃ and MR ₄ of the motors M ₃ and M ₄ respectively have gears G ₆ and G ₁₁ on both sides thereof. G ₇
And G ₈ and G ₉ are meshed with each other. Then, the gears _G 6 ~G ₉ is fixed to each drive shaft _DR 6 _{~DR 9,} therefore, becomes possible, each of which rotates the auger shaft _R 6 to R _9. The lower ends of the rotary shafts MR ₃ and MR ₄ of the motors M ₃ and M ₄ are supported by ordinary bearings on the upper surfaces of shaft support brackets B ₁ and B ₂ provided in the middle stage of the gear box 21. .

FIG. 14 and FIG. 15 show the E section and the F section in FIG. 13, and from this figure, the motors M ₃ and M are shown.
₄ and the auger axes (R ₆ , R ₇ ) R ₈ and R ₉ become clear. As shown in FIG. 14, the rotation axis MR of the motor M _4
4 is a top plate of the gear box 21 and one bracket B ₂
Of which is pivotally supported at an upper surface, a gear _{G 11} which is fixed to the rotary shaft MR ₄ meshes with the gear _G 8, _{G 9} in the left and right in the figure, via a drive shaft _DR 8, DR ₉ of integrated The auger shafts R ₈ and R ₉ are driven to rotate. This has the same structure on the motor M ₃ side. An ordinary bearing is provided on the lower surface side of the bracket B ₂ and supports the upper end portion of another drive shaft DR ₅ (see FIG. 15).

FIG. 15 shows the F cross section in FIG.
, The motor M_Three, M_FourAnd auger axis R_Four, R₅Place with
The relationship is well represented. Both sides of the middle stage of the gearbox 21
Bracket B provided on the surface₁, B_TwoIs the top of each
Data M_Three, M_FourAxis of rotation MR _Three, MR_FourThe end of
Each auger axis R on the bottom surface_Four, R₅Drive coupled to
Axis DR_Four, DR₅Supports the upper end of the. And the
Drive axis DR_Four, DR₅Gear G fixed to_Four, G₅Is before
As mentioned above, the central gear G_ThreeEngaging and engaging with
Is.

FIG. 16 shows a ground improvement apparatus of the present invention.
1 schematically shows an example of a set of a large number of augers.
In the above embodiment, the auger part has a total of nine augers.
It is composed of a moth shaft and an auger head. And figure
Similar to the case shown in 9, the central auger axis R_ThreeBut
The longest auger head OH_ThreeIs at the bottom, followed by
Auger axis R₆~ R₉Auger head OH₆~ O
H₉Is located in the middle stage, and the auger axis R₁, R _Two, R_Four, R₅
Auger head OH₁, OH_Two, OH_Four, OH₅
Can be arranged at the top. This
By determining the position of the head as shown in
Prevent interference and reduce the gap between each head in plan view.
And are possible. However, it is limited to such upper and lower arrangement gaps.
It is not fixed.

FIG. 16 further shows a special side view shape of the auger head. As for the structure of each auger head OH _n , a conventionally known drilling head having a flat bottom surface can be used as will be described with reference to FIG. 2. However, for example, as shown in FIG. 16, its side view shape is a triangular pyramid shape. You can also The plane projection shape of each of the auger heads OH _n can be the same as that shown in FIG.

FIG. 16 also schematically shows a situation in which the improved ground GL is excavated and the ground is improved by using the ground improving apparatus of the present invention. That is, by the respective auger heads OH _{1 to} OH _{9 of the} auger unit 20 driven by the auger drive device portion as in the first and second embodiments, excavation and injection of a hardening agent and a stirring blade in the state shown in the figure. OF _n
Stirring is performed.

The X portion in the figure shows a portion where the excavated soil and the liquid hardening agent are agitated and mixed by the ground improvement work to become a soil hardening agent slurry as a whole. The width W of the ground improvement execution portion X is about 1 m, and the construction depth is arbitrary, but in the normal case, the depth d can be 3 to 7 m. In addition, by continuously performing such improvement work for one step in the longitudinal direction, it is possible to proceed with a ground improvement area with a width of about 1 m and an arbitrary length of about 1 m for each step. The construction distance for one day is as described later.

Next, an embodiment in which the ground improvement apparatus and ground improvement method of the present invention are applied to underground buried pipe construction will be described with reference to FIGS. 17 and 18. FIG. 17
The ground improvement areas Y and Y shown in a mesh pattern in FIG.
It corresponds to the ground improvement construction part X in
The above-mentioned ground improvement device 10 according to the present invention is used to schematically show a side cross-section of a site where the ground improvement work is performed in one day with respect to the ground GL which is the planned pipe burying area. Therefore, the width of the Y and Y ground improvement areas is, for example, about 1 m, and the construction depth can be, for example, about 5 m. Further, the construction distance is an arbitrary distance corresponding to the unit of the number of buried pipes that need to be constructed in one day, such as two pipes P to be buried, and the corresponding distance portion. For example, from the left side to the right side of the figure, one step of excavation and stirring progresses by about 1 m.

After the ground improvement area for one day has been constructed in this manner, or after the ground has been improved for at least the distance of one buried pipe, the ground is improved by using a pipe pushing and embedding machine (not shown). The pipe P is buried up to a predetermined position in a state where the improved region is uncured. That is, in the present invention, the soil improvement area Y that matches the thickness, length and burial depth of the buried pipe using the above-mentioned ground improvement device 10 is injected with a hardening agent at the same time as excavation, and mixed and stirred to cure the soil. In addition to forming the agent slurry, the buried pipe P is pushed and buried.

Therefore, when cement milk, for example, is used as a curing agent for making a soil curing agent slurry, its strength after curing is 2 kg / cm ^{2 to} 3 kg / c.
It is convenient to set the amount of the curing agent so that it becomes approximately m ² . Each of the buried pipes P, P is provided with a cap CP or the like at both ends thereof to prevent the inflow of the soil curing agent slurry from both ends of the buried pipe P.

FIG. 18 shows a part of the work for connecting the connecting portion of the pipes P, P buried as shown in FIG. 17 after the hardening of the ground improvement portion. That is, after the pipes P and P are buried at the same time as the ground improvement work by the ground improvement method of the present invention, the so-called work is performed on the portion corresponding to the connection portion of the buried pipes P and P after the improvement area is hardened. A manhole MH for use is drilled. In this case, for example, the strength of the area where the ground improvement has been completed is 2 kg / cm ^{2 to} 3 as described above.
Since it is set to kg / cm ² , it is possible to easily pierce using a well-known excavator such as a backhoe, and there is no concern that the earth and sand of the open hole will collapse. Also, in the ground improvement area having the above strength,
There is no need to perform work such as rolling compaction again on the road surface. The work of connecting the buried pipe and the like has little direct relation to the present invention, and thus the description thereof is omitted.

[0036]

According to the ground improvement device of the present invention, it is easy to synchronously rotate a large number of auger shafts,
Moreover, it is possible to simultaneously improve the ground in any given area. Therefore, in particular, it is possible to extremely rapidly and efficiently carry out ground improvement work in a long and narrow construction area such as underground pipe burying work. In addition, a device having a fixed width that requires ground improvement can be used, and the ground improvement device can be extremely efficient. Furthermore, in the ground improvement method of the present invention, since a considerably wide substantially rectangular surface can be improved in one step, the construction speed and construction efficiency are improved, and the ground improvement work suitable for underground pipe burying work, for example, can be performed. It has become possible.

[Brief description of drawings]

FIG. 1 is a front view of a ground improvement device according to the present invention.

FIG. 2 is a side view of the ground improvement device shown in FIG.

FIG. 3 is a front view of the auger shaft drive unit according to the first embodiment having a D cross section of a gear box.

FIG. 4 is a view on arrow G in FIG.

5 is a sectional view taken along line A in FIG.

6 is a sectional view taken along line B in FIG.

7 is a sectional view taken along line E in FIG.

8 is a sectional view taken along line F in FIG.

FIG. 9 is a plan projection view of the auger head in the first embodiment.

FIG. 10 is a front view showing a cross section of a gear box D of an auger shaft drive portion according to a second embodiment.

11 is a view on arrow G in FIG.

12 is a sectional view taken along line A in FIG.

13 is a B sectional view of FIG.

14 is a sectional view taken along line E of FIG.

15 is a sectional view taken along line F of FIG.

FIG. 16 is a conceptual diagram of a ground improvement process using the device of the present invention.

FIG. 17 is an explanatory diagram in which the construction method of the present invention is used for underground pipe burying work.

18 is an explanatory diagram of the pipe burying work in FIG.

FIG. 19 is an explanatory diagram of a conventional example in pipe burying work.

[Explanation of symbols]

10 Ground Improvement Device 11 Base Machine 13 Bogie Section 15 Auger Head 17 Auger Elevating Means 20 Auger Section 21 Gear Box 24 Auger Frame M Motor OH _n Auger Head OF _n Stirring Blade G Gear DR (Auger Axis) Drive Axis R Auger Axis SW Swivel bearing P buried pipe

Continuation of front page (56) Reference JP 62-225688 (JP, A) JP 7-173829 (JP, A) JP 7-279154 (JP, A) JP 1-219210 (JP , A) Japanese Unexamined Patent Publication No. 5-272286 (JP, A) Actually developed 51-157109 (JP, U) Actually developed 56-87527 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) E02D 3/12 102 E02F 5/02

Claims (4)

(57) [Claims] 1. A ground improvement device having a multi-axis auger portion that is vertically movable in a guide of a base machine, wherein the multi-axis auger portion has a plurality of drive motors, and a large number of auger shafts are provided by the motors. The multi-axle auger has a gear train for synchronously driving
The central auger is composed of eight winding auger shafts.
The large excavating head on the shaft is at the bottom, and there are four
There is a medium-sized drilling head on the shaft, and four more
A small excavating head of a moth shaft is located, and each auger shaft has an excavating head capable of ejecting a curing agent and a stirring blade, and an approximately rectangular arbitrary area portion is soil curing agent slurry by one excavation stirring process. Ground improvement device that can be in the form of a ground. 2. The contract wherein the drive motor is 2 or 4 units.
The ground improvement device according to claim 1. 3. A ground improvement device having a large number of auger shafts.
Using excavated soil and hardener as a soil hardener slurry
It is a ground improvement method to be carried out, one large in the center of the bottom
Drilling head and 4 middle sized drilling heads and 4 upper tiers
The multi-axis auger part consisting of
Performed in one process over a certain area of the shape,
Steps are carried out sequentially adjacent to each other in a certain direction, resulting in a certain width of
Characterized by enabling rapid ground improvement construction in a long construction area
Ground improvement method. 4. The ground improvement method according to claim 3, wherein the elongated construction area having a constant width is a pretreatment step for embedding an underground pipe.