JP6883808B2 - Underground joining method and excavator - Google Patents

Description

The present invention relates to a technique for underground joining a new pipe to an existing pipe or an existing manhole.

Conventionally, a slide hood method has been known as a method of joining a new pipe to an existing pipe in the ground (for example, Patent Document 1 below). In the slide hood construction method, the slide hood provided on the outer circumference of the excavator is slid toward the front of the excavator from the excavator that has reached just before the existing pipe, and is brought into contact with the existing pipe. Next, the slide hood and the existing pipe are joined, and the inside of the slide hood and the inside of the existing pipe are communicated with each other by removing the inside of the joint portion between the existing pipe and the slide hood among the existing pipes. The slide hood will eventually function as the tip of the new pipe. According to such a construction method, the gap between the excavator and the existing pipe can be made as small as possible, so that the inside of the joint of the existing pipe for communicating the existing pipe and the slide hood can be removed and the excavator can be safely recovered. It can be carried out.

Japanese Unexamined Patent Publication No. 2003-20892

However, with the conventional construction method, it is difficult to completely stop the earth and sand near the outer circumference of the slide hood. Alternatively, it was necessary to combine it with a large-scale water-stopping method such as the freezing method. Therefore, it cannot be said that the slide hood method is sufficiently widespread. For this reason, it is desirable to provide a slide hood construction method that can be easily implemented and that can ensure water stoppage.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following forms, for example.

According to the first aspect of the present invention, there is provided a method of underground joining a new pipe to an existing pipe or an existing manhole. This method comprises the step of preparing a digger. The excavator is a cutter face plate configured to be rotatable, a ground improvement material injection nozzle attached to the cutter face plate and configured to inject the ground improvement material at ultra-high pressure, and a ground improvement material injection nozzle arranged on the outer periphery of the excavator for excavation. It is equipped with a slide hood that is configured to slide in the digging direction of the machine. The above method further comprises a first step of injecting the ground improving material from the ground improving material injection nozzle toward the front in the excavation direction to improve the ground near the existing pipe or the existing manhole, and the first step. After at least a part of the injected ground improvement material is solidified, the ground improvement material is injected again from the ground improvement material injection nozzle, and the slide is performed by partially destroying at least a part of the solidified ground improvement material. A second step of forming a movable path of the hood, and after the second step, a third step of sliding the slide hood forward in the digging direction to reach the existing pipe or the existing manhole, and the existing one. A fourth step of joining the slide hood that has reached the pipe or the existing manhole and the existing pipe or the existing manhole, and removing the portion of the existing pipe or the existing manhole located inside the slide hood. I have.

According to such a method, good water stopping property can be ensured by injecting a ground improving material into the vicinity of the existing pipe or the existing manhole to improve the soil around the existing pipe. Moreover, even after at least a part of the injected ground improvement material has solidified, the slide hood can be moved by injecting the ground improvement material again to partially destroy the solidified ground improvement material. Is formed. Therefore, even after at least a part of the injected ground improvement material has solidified, the slide hood can be slid to reach the existing pipe or the existing manhole. That is, it is possible to achieve both the slide hood method and ensuring water stoppage by a simple method.

According to the second aspect of the present invention, in the first aspect, the second step includes a step of injecting a ground improving material parallel to the excavation direction from a position overlapping the slide hood when viewed in the excavation direction. There is. According to this form, the ground improvement material is re-injected only to the portion required as the movable path of the slide hood, which is efficient.

According to the third embodiment of the present invention, in the first or second embodiment, the above method is after the third step and before the fourth step, the solution is injected from the ground improvement material injection nozzle. It also has a process of injecting material. According to such a form, when the water stopping property obtained by the ground improvement by the first step is not sufficient, the insufficient water stopping property can be supplemented by the solution injection material.

According to the fourth aspect of the present invention, in any of the first to third embodiments, the method is on the outer periphery of the excavator after the third step and before the fourth step. It further includes a step of supplying a solution injection material. According to such a form, when water enters the outer periphery of the excavator from the rear of the excavator, the water can be stopped.

According to the fifth aspect of the present invention, in any one of the first to fourth forms, the excavator is further provided on the main body of the excavator and has a jack for pushing the slide hood forward in the excavation direction. I have. The fourth step includes a step of removing the portion located inside the slide hood by moving the excavator forward after separating the jack from the slide hood. According to such a form, a part of the existing pipe or the existing manhole can be easily removed by the excavator.

According to a sixth aspect of the present invention, a digger is provided. This excavator has a rotatably configured cutter face plate and a ground improvement material injection nozzle that is attached to the cutter face plate and is configured to inject ground improvement material at ultra-high pressure toward the front in the excavation direction of the excavator. It is provided with a slide hood arranged on the outer periphery of the excavator and slidable in the excavation direction, and a moving portion for moving the ground improvement material injection nozzle in a direction intersecting the excavation direction. The ground improvement material injection nozzle is configured to be movable at a position overlapping the slide hood when viewed in the excavation direction by a moving portion, and is configured to be capable of injecting the ground improvement material in parallel with the excavation direction. According to such an excavator, the same effect as that of the second embodiment is obtained.

It is a schematic diagram of the excavator according to one Embodiment of this invention. It is a schematic front view which shows the arrangement of the ground improvement material injection nozzle. It is explanatory drawing which shows the direction of the ground improvement material injection nozzle. It is explanatory drawing which shows the state which the ground improvement is performed by the excavator. It is explanatory drawing which shows the state which the ground improvement was completed. It is explanatory drawing which shows the state that the movable path of a slide hood is formed after the ground improvement is completed. It is explanatory drawing which shows the state which the slide hood reached the existing pipe. It is explanatory drawing which shows the state that the water stop is performed in a complementary manner. It is explanatory drawing which shows the state which a part of the steel segment of an existing pipe was removed, and the slide hood was welded. It is explanatory drawing which shows the state which the equipment inside the excavator is removed. This is an explanation showing the state in which the underground joint is completed.

FIG. 1 is a schematic view of an excavator 10 according to an embodiment of the present invention. The excavator 10 is used for underground joining a new pipe to an existing pipe 90 in the soil. FIG. 1 shows a state in which the excavator 10 excavates in the excavation direction D1 while building the Hume pipe 80 behind the excavation direction D1 and reaches the vicinity of the existing pipe 90. Although this embodiment will be described as a propulsion method, it can also be applied to a shield method. In the case of the shield method, reference numeral 80 represents a segment. The excavator 10 includes an excavator main body 20, a cutter face plate 30, and a slide hood 40. The excavator 10 is a well-known excavator as disclosed in Japanese Patent Application Laid-Open No. 2012-014707, except for the following points, and detailed description thereof will be omitted.

The cutter face plate 30 is connected to a shaft extending in the excavator main body 20, and is configured to be rotatable. The cutter face plate 30 is provided with a plurality of cutters, at least one cutting injection nozzle, and at least one (four in this embodiment) ground improvement material injection nozzles (all of which are FIG. 1). Then, the figure is omitted). The cutting injection nozzle is used to inject an abrasive slurry (mixture of abrasive, polymer, water, etc.) in front of the digging direction D1 at an ultrahigh pressure (for example, 245 MPa) to cut an obstacle in the ground. It is provided. The ground improvement material injection nozzle directs the ground improvement material (for example, a mixture of a sodium silicate solution and cement milk, or a mixture of a sodium silicate solution and a hardening agent solution) toward the front of the excavation direction D1 at an ultrahigh pressure (for example). For example, it is provided for injecting at 245 MPa).

The slide hood 40 is arranged on the front side in the excavation direction D1 of the outer circumference of the excavator main body 20. The slide hood 40 is configured to be slidable in the excavation direction D1. Specifically, a jack 41 (shown only in FIG. 7) is provided in the excavator main body 20. The jack 41 can engage with the slide hood 40 and push the slide hood 40 forward in the digging direction D1.

FIG. 2 is a schematic front view showing the arrangement of the ground improvement material injection nozzles. FIG. 3 is an explanatory diagram showing the orientation of the improvement material injection nozzles in each area. The cutter face plate 30 is provided with four ground improvement material injection nozzles 31 to 34. The ground improvement material injection nozzle 31 is provided near the outer periphery of the cutter face plate 30, and is angled outward in the radial direction with respect to the excavation direction D1. Therefore, the ground improvement material injection nozzle 31 can inject the ground improvement material at an angle outward in the radial direction with respect to the excavation direction D1. The ground improvement material injection nozzle 32 is provided slightly inside the ground improvement material injection nozzle 31 in the radial direction, and is oriented parallel to the excavation direction D1. The ground improvement material injection nozzle 33 is provided on the inner side in the radial direction with respect to the ground improvement material injection nozzle 32, and is oriented in parallel with the excavation direction D1. Therefore, the ground improvement material injection nozzles 32 and 33 can inject the ground improvement material in parallel with the excavation direction D1. The positions of these ground improvement material injection nozzles 31 to 33 are fixed.

The ground improvement material injection nozzle 34 is provided on the side opposite to the ground improvement material injection nozzles 31 to 33 with respect to the center of the cutter face plate 30. The ground improvement material injection nozzle 34 is oriented parallel to the excavation direction D1. Therefore, the ground improvement material injection nozzle 34 can inject the ground improvement material in parallel with the excavation direction D1. The ground improvement material injection nozzle 34 is configured to be movable in the direction intersecting the excavation direction D1 (in the present embodiment, the radial direction) by the cylinder 35. More specifically, as shown in FIG. 2, the ground improvement material injection nozzle 34 is configured to be movable at a position (indicated by a dotted line in FIG. 2) overlapping the slide hood 40 when viewed in the excavation direction D1. The ground improvement material injection nozzle 34 is normally retracted inward from the outer circumference of the excavator 10.

The procedure for performing underground joining using the excavator 10 will be described below. When the excavator 10 reaches a predetermined range with respect to the existing pipe 90, first, the ground improvement in the vicinity of the existing pipe 90 is performed. In FIG. 1, the region to be ground-improved is shown as the ground-improved region 70. The range of the ground improvement area 70 (improvement width W2 in the excavation direction D1) is, for example, L + 1 (m), where L is the body length of the excavator main body 20. The ground improvement of the ground improvement area 70 is carried out step by step in consideration of the reach of the ground improvement material injected from the ground improvement material injection nozzles 31 to 34. FIG. 1 shows a case where ground improvement is performed by dividing into four ground improvement small areas 71 to 75. The width W1 of each of the ground improvement small areas 71 to 75 in the excavation direction D1 is, for example, 1.0 to 1.5 m.

FIG. 4 shows a state in which the ground improvement is performed for the ground improvement small area 71. When improving the ground, first, the pack material 51 is injected from the pack material injection device 50 provided inside the excavator main body 20 to the outer periphery of the excavator 10. As the pack material 51, a gel-like fluid or a fluid that changes from a liquid to a gel over time (for example, an aqueous solution containing sodium silicate and a curing agent) can be used. A plurality of pack material injection devices 50 are provided along the circumferential direction. Further, at a position of the slide hood 40 corresponding to each pack material injection device 50, a through hole for supplying the pack material 51 from the pack material injection device 50 to the outside of the slide hood 40 is formed. The through hole may be configured to be opened and closed automatically or manually. By supplying the pack material 51 around the excavator 10 prior to the injection of the ground improvement material, the ground improvement material enters between the outer circumference of the excavator 10 and the ground and solidifies, so that the excavator 10 cannot move forward. Can be prevented from becoming.

Next, the excavator 10 injects the ground improvement material 37 from the ground improvement material injection nozzle 31 to improve the ground improvement small region 71 (that is, the region in front of the excavator 10 and outside in the radial direction in the excavation direction D1). To do. Specifically, the excavator 10 first injects a predetermined amount of the ground improvement material 37 from the ground improvement material injection nozzle 31. Next, the excavator 10 rotates the cutter face plate 30 by a predetermined angle. Next, the excavator 10 injects a predetermined amount of the ground improvement material 37 from the ground improvement material injection nozzle 31 at the position after rotation. By repeating these steps until the cutter face plate 30 rotates 360 degrees (that is, one rotation), the ground improvement small area 71 is ground-improved within a substantially ring-shaped range. The time required for the cutter face plate 30 to make one rotation in such a process is, for example, 1 to 4 days.

When the injection of the ground improvement material into the ground improvement small area 71 is completed in this way, the ground improvement material 37 is cured until it solidifies. Since the cutter face plate 30 makes one rotation very slowly during the ground improvement of the ground improvement small area 71, the ground improvement material 37 injected at the initial stage of rotation of the cutter face plate 30 has already solidified when the cutter face plate 30 makes one rotation. doing. Therefore, the ground improving material injected in the middle to late rotation of the cutter face plate 30 is cured until it solidifies.

When the ground improvement material of the ground improvement small area 71 is solidified, the excavator 10 then advances by the width W1 of the excavation direction D1 of the ground improvement small area 71, and then ground improvement in the same manner as the ground improvement small area 71. The ground of the small area 72 is improved. Then, when the ground improvement material in the ground improvement small area 72 is solidified, the ground improvement is also sequentially performed in the ground improvement small areas 73 and 74 in the same manner.

Next, the excavator 10 improves the ground in the ground improvement small area 75. At this time, the cutter face plate 30 is located immediately before the existing pipe 90. In addition to the ground improvement material injection nozzle 31, ground improvement material injection nozzles 32 and 33 are also used for injecting the ground improvement material 37 into the ground improvement small area 75. Therefore, the ground improvement small area 75 is not in a substantially ring-shaped range, but in a substantially columnar range. FIG. 5 shows a state in which the ground improvement of the ground improvement small area 75 is completed in this way.

When the ground improvement material 37 is injected into the ground improvement small area 75, the excavator 10 sees the ground improvement material injection nozzle 34 in the excavation direction D1 without waiting for the ground improvement material 37 to solidify. And move it to the position where it overlaps with the slide hood 40 (the position shown by the dotted line in FIG. 2). Then, as shown in FIG. 6, the excavator 10 reinjects the ground improvement material from the ground improvement material injection nozzle 34 in the direction parallel to the excavation direction D1 while rotating the cutter face plate 30. In this step, for example, the rotation of the cutter face plate 30 and the injection of the ground improvement material 37 from the ground improvement material injection nozzle 34 may be continuously performed at the same time. Alternatively, the cutter face plate 30 may be rotated intermittently, and the ground improvement material 37 may be ejected from the ground improvement material injection nozzle 34 while the cutter face plate 30 is stopped.

As described above, when the cutter face plate 30 makes one rotation, the ground improvement material 37 injected at the initial stage of rotation has already solidified, but this reinjection destroys the already solidified ground improvement material 37. Rotate. This area to be destroyed is an area that overlaps with the slide hood 40 in the excavation direction D1 due to the position and orientation of the ground improvement material injection nozzle 34. Therefore, this destroyed area functions as a movable path of the slide hood 40. The rotation of the cutter face plate 30 in this re-injection step is much faster than when the ground improvement region 70 is ground-improved (for example, one rotation in a few minutes). This is because it is sufficient if the movable path of the slide hood 40 can be formed (that is, if the solidified ground improvement material 37 of the ground improvement small area 75 can be destroyed only in a limited area that becomes the path of the slide hood 40).

After forming the movable path, the excavator 10 then retracts the ground improvement material injection nozzle 34 inward from the outer circumference of the excavator 10. Then, as shown in FIG. 7, the excavator 10 uses the jack 41 to direct the slide hood 40 forward in the excavation direction in the direction of arrow A1 on the movable path until it reaches the existing pipe 90. Slide it. The tip of the slide hood 40 (the front end in the excavation direction D1) is preformed in a curved shape so as to match the outer shape of the existing pipe 90 (best shown in FIG. 1). Therefore, the entire outer shell of the tip of the slide hood 40 comes into contact with the existing pipe 90. In this state, the ground improvement material 37 in the ground improvement small area 75 is cured until it is completely solidified. Note that FIG. 7 also shows a state in which a part 93 (connection portion with the slide hood 40) of the concrete (secondary lining) 91 of the existing pipe 90 has been removed from the inside of the existing pipe 90 in advance.

After the curing period has elapsed, the water stoppage is confirmed by opening the partition valve 21 provided at the boundary between the cutter face plate 30 and the excavator main body 20. As a result, when it is confirmed that the water stoppage is not sufficient, the excavator 10 is radially outward from the pack material injection device 50 through the through hole formed in the slide hood 40, as shown in FIG. A solution-type injection material (for example, a mixture of sodium silicate, a curing agent, a polymer, and water) is supplied toward. As a result, when water has entered the outer periphery of the excavator 10 from behind the excavator 10, the water can be stopped. In this case, if a device for supplying the solution-type injection material outward in the radial direction is provided separately from the pack material injection device 50, the solution-type injection material may be supplied from the device.

Further, the excavator 10 injects the solution type injection material from at least one of the ground improvement material injection nozzles 31 to 34. As a result, the water entering from the connection point between the existing pipe 90 and the slide hood 40 can be stopped. Instead of diverting the ground improvement material injection nozzles 31 to 34, an injection nozzle dedicated to the solution type injection material may be provided. Both of these two water stopping steps may be performed at the same time, or only one of them may be performed first, and as a result, if water stopping cannot be confirmed, the other may be performed in succession. Of course, only one of them may be performed.

When the water stoppage can be confirmed, then, as shown in FIG. 9, the connecting portion (that is, the portion 94 located inside the slide hood 40) of the steel segment 92 is removed, and the front of the cutter face plate 30 is removed. Moreover, the ground of the region 95 inside the slide hood 40 is removed. These are carried out to the starting stand as shown by the arrow A2 via the excavator main body 20. Further, the slide hood 40 and the steel segment 92 of the existing pipe 90 are joined by being welded at their abutting portions (welded portions are indicated by reference numerals 42). This removal and welding work is performed locally and sequentially. That is, the removal of the entire range and the welding are completed by repeatedly performing the steps of removing the portion 94 and the ground of the area 95 in a limited range, and then welding the removed portion.

Next, as shown in FIG. 10, the equipment (cutter face plate 30 and other equipment 23) inside the excavator 10 is disassembled, and as shown by the arrow A3, the equipment is carried out to the starting stand.

Next, as shown in FIG. 11, after joining the slide hood 40 and the skin plate 22 forming the outer circumference of the excavator main body 20, the secondary lining 96 is constructed with concrete. In this way, the new pipe including the slide hood 40, the skin plate 22 and the Hume pipe 80 is underground-joined to the existing pipe 90.

According to the above-mentioned construction method, good water stopping property can be ensured by injecting the ground improvement material 37 in the vicinity of the existing pipe 90 to form the ground improvement region 70. Moreover, even after at least a part of the injected ground improvement material 37 has solidified, the ground improvement material 37 is injected again to partially destroy the solidified ground improvement material 37, thereby causing the slide hood. Forty movable paths are formed. Therefore, even after at least a part of the injected ground improvement material 37 has solidified, the slide hood 40 can be slid to reach the existing pipe 90. That is, it is possible to achieve both the slide hood method and ensuring water stoppage by a simple method. Moreover, if sufficient water stopping is not obtained only by forming the ground improvement region 70, the insufficient water stopping can be supplemented by the solution injection material.

Further, the re-injection of the ground improvement material 37 for forming the movable path of the slide hood 40 is performed parallel to the excavation direction D1 from a position overlapping the slide hood 40 when viewed in the excavation direction D1. That is, it is efficient because the ground improvement material 37 is sprayed again only on the portion necessary for the movable path.

Although some examples of the present invention have been described above, the above-described examples of the invention are for facilitating the understanding of the present invention and do not limit the present invention. The present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes an equivalent thereof. Further, in the range where at least a part of the above-mentioned problems can be solved, or in the range where at least a part of the effect is exhibited, the scope of claims and the combination of each component described in the specification can be combined or omitted. ..

For example, in the above embodiment, the steel segment 92 (or the steel segment 92 and the concrete (secondary lining) 91) is removed by the excavator 10 before dismantling the equipment inside the excavator 10. May be good. Specifically, the slide hood 40 reaches the existing pipe 90, water stoppage is confirmed, the jack 41 is separated from the slide hood 40, and then the excavator 10 is advanced to advance the steel segment 92 (or the steel segment 92 (or). The steel segment 92 and concrete (secondary lining) 91) may be removed.

Alternatively, any of the ground improvement material injection nozzles 31 to 34 may be nozzles whose angles can be adjusted. Further, instead of the ground improvement material injection nozzle 34, the ground improvement material injection nozzle 31 may be used to form a movable path of the slide hood 40. Further, at least one arbitrary number of ground improvement material injection nozzles may be provided. Further, the excavator 10 can be used in the case of underground joining the existing manhole and the new pipe instead of the existing pipe 90.

10 ... Excavator 20 ... Excavator body 21 ... Partition valve 22 ... Skin plate 23 ... Excavator equipment 30 ... Cutter face plate 31-34 ... Ground improvement material injection nozzle 35 ... Cylinder 37 ... Ground improvement material 40 ... Slide hood 41 ... Jack 42 ... Welded part 50 ... Pack material injection device 51 ... Pack material 70 ... Ground improvement area 71-75 ... Ground improvement small area 80 ... Hume pipe 90 ... Existing pipe 91 ... Concrete (secondary lining)
92 ... Steel segment 93 ... Removal part 94 ... Removal part 95 ... Removal area 96 ... Secondary lining

Claims (8)

It is a method of underground joining a new pipe to an existing pipe or an existing manhole.
With the process of preparing a digger,
The excavator
With a rotatably configured cutter face plate,
A ground improvement material injection nozzle attached to the cutter face plate and configured to inject the ground improvement material at ultra-high pressure,
It is provided with a slide hood which is arranged on the outer circumference of the excavator and is configured to be slidable in the excavation direction of the excavator.
The method further
The ground improvement material is injected from the ground improvement material injection nozzle toward the front in the excavation direction, and the ground is in the vicinity of the existing pipe or the existing manhole, and is a region radially outer of the slide hood. And the first step of improving the ground of the area including the area inside in the radial direction,
After at least a part of the ground improvement material injected by the first step is solidified, the ground improvement material is injected again from the ground improvement material injection nozzle to solidify at least a part of the ground improvement material. The second step of forming the movable path of the slide hood by partially destroying the slide hood, and
After the second step, the slide hood is slid forward of the cutter face plate in the digging direction while maintaining the position of the cutter face plate in the digging direction, and the slide hood is slid to the existing pipe or the existing pipe or the said. The third step to reach the existing manhole and
The slide hood that has reached the existing pipe or the existing manhole is joined to the existing pipe or the existing manhole, and the portion of the existing pipe or the existing manhole that is located inside the slide hood is formed. A method comprising a fourth step of removal. The method according to claim 1.
The second step is a method comprising a step of injecting the ground improving material in parallel with the digging direction from a position overlapping with the slide hood when viewed in the digging direction. It is a method of underground joining a new pipe to an existing pipe or an existing manhole.
With the process of preparing a digger,
The excavator
With a rotatably configured cutter face plate,
A ground improvement material injection nozzle attached to the cutter face plate and configured to inject the ground improvement material at ultra-high pressure,
It is provided with a slide hood which is arranged on the outer circumference of the excavator and is configured to be slidable in the excavation direction of the excavator.
The method further
A first step of injecting the ground improvement material from the ground improvement material injection nozzle toward the front in the excavation direction to improve the ground in the vicinity of the existing pipe or the existing manhole.
After at least a part of the ground improvement material injected by the first step is solidified, the ground improvement material is injected again from the ground improvement material injection nozzle to solidify at least a part of the ground improvement material. The second step of forming the movable path of the slide hood by partially destroying the slide hood, and
After the second step, a third step of sliding the slide hood forward in the excavation direction to bring the slide hood to the existing pipe or the existing manhole.
The slide hood that has reached the existing pipe or the existing manhole is joined to the existing pipe or the existing manhole, and the portion of the existing pipe or the existing manhole that is located inside the slide hood is formed. With a fourth step to remove
The second step is a method comprising a step of injecting the ground improving material in parallel with the digging direction from a position overlapping with the slide hood when viewed in the digging direction. The method according to any one of claims 1 to 3.
A method further comprising a step of injecting a solution injection material from the ground improvement material injection nozzle after the third step and before the fourth step. The method according to claim 4.
A method further comprising a step of supplying the solution injection material to the outer periphery of the excavator after the third step and before the fourth step. The method according to any one of claims 1 to 5.
The excavator is further provided on the main body of the excavator and is provided with a jack for pushing the slide hood forward in the excavation direction.
The fourth step is a method comprising a step of removing the portion located inside the slide hood by moving the excavator forward after separating the jack from the slide hood. It ’s a digger,
With a rotatably configured cutter face plate,
A ground improvement material injection nozzle attached to the cutter face plate and configured to inject the ground improvement material at an ultrahigh pressure toward the front in the excavation direction of the excavator.
A slide hood arranged on the outer circumference of the excavator and slidable in the excavation direction,
A moving portion for moving the ground improvement material injection nozzle in a direction intersecting the excavation direction is provided.
The ground improvement material injection nozzle is configured to be movable by the moving portion at a position overlapping the slide hood when viewed in the excavation direction, and is configured to be capable of injecting the ground improvement material in parallel with the excavation direction. ,
The excavator injects the ground improvement material from the ground improvement material injection nozzle toward the front in the excavation direction, and after at least a part of the ground improvement material is solidified, the circumference of which the ground improvement material has been injected. An excavator that operates to inject the ground improvement material in parallel with the excavation direction from the ground improvement material injection nozzle arranged at a directional position and a radial position that overlaps with the slide hood when viewed in the excavation direction. .. It ’s a digger,
With a rotatably configured cutter face plate,
A ground improvement material injection nozzle attached to the cutter face plate and configured to inject the ground improvement material at an ultrahigh pressure toward the front in the excavation direction of the excavator.
A slide hood arranged on the outer circumference of the excavator and slidable in the excavation direction,
A moving portion for moving the ground improvement material injection nozzle in a direction intersecting the excavation direction is provided.
The excavator
The ground improvement material is injected from the ground improvement material injection nozzle toward the front in the excavation direction.
After at least a part of the ground improvement material has solidified, a radial position that overlaps with the slide hood when viewed in the excavation direction from the ground improvement material injection nozzle arranged at a circumferential position where the ground improvement material has been injected. The ground improvement material is injected so that at least a part of the solidified ground improvement material located in can be partially destroyed.
An excavator that operates to slide the slide hood forward of the cutter face plate in the excavation direction while maintaining the position of the cutter face plate in the excavation direction.

Images