Excavator and ground improvement method

Abstract

To radially expand the range in which ground improvement can be performed by a tunneling machine placed underground.SOLUTION: A tunneling machine comprises a tunneling machine body, a cutter head section arranged forward in the tunneling direction relative to the tunneling machine body and configured to be rotatable about a rotation axis relative to the tunneling machine body, a first injection nozzle provided in the cutter head section and configured to spray soil improvement material at high pressure toward the forward side in the tunneling direction, and an injection nozzle moving mechanism configured to move the first injection nozzle in a radial direction relative to the rotation axis. The injection nozzle moving mechanism is configured to be able to move the first injection nozzle radially outward from the radial outer edge of the cutter head section.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a technique for ground improvement by an excavator disposed underground.

Background Art

[0002] When constructing a pipeline or a tunnel by excavating soil with an excavator, it may be necessary to improve the ground around the excavation path. The following Patent Document 1 discloses a technique of jetting a ground improvement material forward in the excavation direction from an injection nozzle fixed to the cutter head portion of an excavator located underground. According to such a ground improvement technique, necessary ground improvement can be performed from underground without affecting the ground environment.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is room for improvement in the ground improvement technique of Patent Document 1. Specifically, since the injection nozzle is fixed to the cutter head portion and the reach of the ground improvement material jetted from the injection nozzle is also small, ground improvement can be performed only in a very limited range around the radial direction of the excavator. For this reason, for example, when there is an underground structure at a position away from the excavator, it has not been possible to improve the ground up to the vicinity thereof. Therefore, a technique capable of expanding the range in which ground improvement can be performed in the radial direction by an excavator disposed underground is required.

Means for Solving the Problems

[0005] The present invention has been made to solve the above-described problems and can be realized, for example, in the following forms.

[0006] According to a first aspect of the present invention, a tunneling machine is provided. The tunneling machine includes a tunneling machine body, a cutter head portion disposed on the front side in the tunneling direction with respect to the tunneling machine body and configured to be rotatable about a rotation axis with respect to the tunneling machine body, a first injection nozzle provided in the cutter head portion and configured to inject a ground improvement material forward in the tunneling direction under high pressure, and an injection nozzle moving mechanism configured to move the first injection nozzle movably in a radial direction with respect to the rotation axis. The injection nozzle moving mechanism is configured to move the first injection nozzle to the outside in the radial direction beyond the outer edge portion in the radial direction of the cutter head portion.

[0007] According to this tunneling machine, the first injection nozzle can be moved to the outside in the radial direction beyond the outer edge portion in the radial direction of the cutter head portion, and the ground improvement material can be injected forward under high pressure from the first injection nozzle. Therefore, the range in which ground improvement can be performed by the tunneling machine disposed in the ground can be expanded in the radial direction (for example, upward). "Injecting the ground improvement material forward under high pressure in the tunneling direction" includes a mode of injecting the ground improvement material forward under high pressure in a direction parallel to the rotation axis of the cutter head portion and a mode of injecting the ground improvement material forward under high pressure in a direction intersecting the rotation axis of the cutter head portion (more specifically, obliquely forward at an angle angled outward in the radial direction).

[0008] According to a second aspect of the present invention, in the first aspect, the first injection nozzle is directed to inject the ground improvement material forward under high pressure in a direction angled outward in the radial direction with respect to the rotation axis. According to this aspect, the range in which ground improvement can be performed can be further expanded in the radial direction compared to a configuration in which the first injection nozzle injects the ground improvement material forward under high pressure in a direction parallel to the rotation axis.

[0009] According to a third aspect of the present invention, in the first or second aspect, the tunneling machine is provided with a second injection nozzle provided in the cutter head portion and configured to inject fluid at high pressure toward the outside in the radial direction in the moving direction of the first injection nozzle. The injection nozzle moving mechanism is configured to be able to move the second injection nozzle together with the first injection nozzle. The second injection nozzle is configured to inject fluid when it is moved radially outside the radially outer edge portion of the cutter head portion together with the first injection nozzle, or before that. According to this aspect, by injecting fluid from the second injection nozzle, the ground on the movement path when the first injection nozzle moves radially outward can be agitated. Therefore, the movement of the first injection nozzle radially outward can be smoothed.

[0010] According to a fourth aspect of the present invention, in any one of the first to third aspects, the tunneling machine has a partition wall that divides the inner space of the tunneling machine body into a chamber exposed to the soil and an in-machine space not exposed to the soil and arranged on the rear side in the tunneling direction with respect to the chamber. The partition wall has a first through hole located below the rotation axis and a second through hole located above the first through hole. The tunneling machine is provided with a conveyor for conveying the excavated soil taken into the in-machine space from the chamber through the first through hole to the rear in the tunneling direction, and a valve for opening and closing the second through hole. The tunneling machine is configured to be able to perform mud discharge from the chamber to the in-machine space through the second through hole by opening the valve when injecting the ground improvement material from the first injection nozzle. According to this aspect, mud discharge can be performed when injecting the ground improvement material from the first injection nozzle through the second through hole located above the first through hole, rather than through the first through hole for taking the excavated soil into the in-machine space. Although a part of the ground improvement material injected from the first injection nozzle returns to the chamber, according to this aspect, it is possible to prevent the ground improvement material that has returned to the chamber from entering up to the position where the first through hole is located. That is, since the ground improvement material that has returned to the chamber does not spread throughout the chamber, the ground improvement material can be quickly taken into the in-machine space. Therefore, it is possible to suppress the solidification of the ground improvement material in the chamber.

[0011] According to the fifth aspect of the present invention, in the fourth aspect, the tunneling machine is configured to be able to supply the mud material into the chamber from the second through hole before injecting the ground improvement material from the first injection nozzle. According to this aspect, it becomes possible to supply the mud material only in the vicinity of the second through hole. In that case, in the chamber, the fluidity increases only in the vicinity of the second through hole, so that the entry range of the ground improvement material returning to the chamber can be further limited. Therefore, the effect of the fourth aspect can be further enhanced.

[0012] According to the sixth aspect of the present invention, there is provided a ground improvement method for performing ground improvement by a tunneling machine disposed underground. This ground improvement method includes a step of disposing a cutter head portion rotatably disposed with respect to the tunneling machine body at a predetermined rotational angle position on the front side in the tunneling direction with respect to the tunneling machine body, a step of moving an injection nozzle provided in the cutter head portion to the outside in the radial direction rather than the outer edge portion in the radial direction of the cutter head portion, and a step of jetting the ground improvement material forward in the tunneling direction from the injection nozzle located outside in the radial direction rather than the outer edge portion. According to this ground improvement method, the same effect as in the first aspect is achieved. Steps corresponding to any one of the second to fifth aspects can also be added to the sixth aspect.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] FIG. 1 is a schematic longitudinal sectional view of a tunneling machine 10 according to an embodiment of the present invention. FIG. 2 is a schematic sectional view taken along line A-A of FIG. 1. In FIG. 2, the main shaft and the screw conveyor, which will be described later, are not shown. FIG. 3 is a view taken in the direction of arrow B of FIG. 1. In the following description, for convenience of explanation, the tunneling direction of the tunneling machine 10 and the direction toward the opposite side thereof are defined as the front-rear direction. Further, the front side in the tunneling direction is defined as the front side of the tunneling machine 10, and the rear side in the tunneling direction is defined as the rear side of the tunneling machine 10.

[0015] As shown in FIG. 1, the tunneling machine 10 includes a tunneling machine body 20 and a cutter head portion 30. Each of the tunneling machine body 20 and the cutter head portion 30 has a substantially cylindrical shape extending in the front-rear direction. The cutter head portion 30 is disposed coaxially with the tunneling machine body 20 on the front side with respect to the tunneling machine body 20. The cutter head portion 30 is supported by a bearing (not shown) and is configured to rotate about a rotation axis AX with respect to the tunneling machine body 20 by the rotational driving force of a drive motor (not shown).

[0016] As shown in FIG. 1, a plurality of spokes 32 (only one spoke 32 extending in the vertical direction is shown in FIG. 1) are spanned inside the cutter head portion 30. The plurality of spokes 32 are arranged so as to extend radially from the substantially cylindrical central portion of the cutter head portion 30 and form a cross shape. A cutter bit 33 for cutting the ground is attached to each of the plurality of spokes 32. A space penetrating the cutter head portion 30 in the front-rear direction is formed at a location where the spokes 32 are not spanned. Note that the number, shape, and arrangement of the spokes 32 are not particularly limited and can be arbitrarily set according to the construction conditions. Further, instead of the spoke type, a face plate type cutter head portion 30 with fewer openings may be adopted.

[0017] As shown in Fig. 1, near the front end of the tunneling machine body 20, a partition wall 40 is formed that divides the internal space of the tunneling machine body 20 into a chamber 24 and an internal machine space 25. The internal machine space 25 is located behind the chamber 24. Excavated soil enters the chamber 24 through a location where the spokes 32 of the cutter head portion 30 are not spanned. On the other hand, since the internal machine space 25 is isolated by the partition wall 40, it is not exposed to the excavated soil. Each facility of the tunneling machine body 20 (for example, the above-mentioned bearings and drive motors) is installed in the internal machine space 25. The cutter head portion 30 has an internal space that is not exposed to the excavated soil.

[0018] As shown in Fig. 1, at approximately the center of the partition wall 40, a main shaft 50 arranged coaxially with the rotation axis AX extends from the internal machine space 25 to the internal space of the spoke 32. The main shaft 50 is fixed to the cutter head portion 30 and rotates integrally with the cutter head portion 30.

[0019] As shown in Figs. 1 and 2, in the lower part of the partition wall 40 (below the rotation axis AX), a first through hole 41 penetrating the partition wall 40 in the front-rear direction is formed. A chamber gate (not shown) for opening and closing it is provided in the first through hole 41. Behind the first through hole 41 in the internal machine space 25, a screw conveyor 55 is arranged. The screw conveyor 55 conveys the excavated soil taken into the internal machine space 25 from the chamber 24 through the first through hole 41 backward during tunneling by the tunneling machine 10.

[0020] As shown in FIGS. 1 and 2, above the partition wall 40 (above the first through hole 41, and in this embodiment, above the rotation axis AX), a plurality of second through holes 42 penetrating the partition wall 40 in the front-rear direction are formed (in FIG. 1, only two second through holes 42 are shown). In this embodiment, one second through hole 42 is disposed directly above the rotation axis AX. This second through hole 42 is located near the uppermost edge between the rotation axis AX and the uppermost edge of the partition wall 40. The remaining two second through holes 42 are symmetrically arranged on the left and right of the one second through hole 42 when viewed in the front-rear direction. The two second through holes 42 are located below the one second through hole 42. In the cabin space 25, three valves 43 for opening and closing the three second through holes 42 are respectively disposed in each of the three second through holes 42.

[0021] As shown in FIG. 1, the cutter head portion 30 is provided with a first injection nozzle 61 and a second injection nozzle 62. The first injection nozzle 61 injects the ground improvement material forward at high pressure. In this embodiment, the first injection nozzle 61 is directed to inject the ground improvement material at high pressure in a direction angled outward in the radial direction with respect to the rotation axis AX. However, the first injection nozzle 61 may be directed to inject the ground improvement material at high pressure parallel to the rotation axis AX. Any material can be used as the ground improvement material. Typically, the ground improvement material is cement-based (for example, a mixture of sodium silicate solution and cement milk), but it may also be solution type (any ground improvement material without cement).

[0022] The second injection nozzle 62 injects the fluid at high pressure outward in the radial direction. Any material can be used as the fluid. For example, the fluid may be a cement-based ground improvement material, a solution type ground improvement material, water, a mud addition material, or the like. The injection pressures of the first injection nozzle 61 and the second injection nozzle 62 can be, for example, 30 to 245 MPa according to the construction conditions.

[0023] In this embodiment, the first injection nozzle 61 and the second injection nozzle 62 are supplied with a ground improvement material and a fluid, respectively, via a pipe 65 (only one pipe 65 is shown in FIG. 1 for simplification, but actually there are a plurality of them) disposed in the internal space of the cutter head portion 30. In this specification, the "pipe" means a hollow body made of any material (e.g., metal, resin, etc.) that can transfer a fluid. The rear ends of the plurality of pipes 65 are connected to a flow path formed inside the main shaft 50 at the front end portion of the main shaft 50. However, the supply paths of the ground improvement material and the fluid to the first injection nozzle 61 and the second injection nozzle 62 can be arbitrarily set.

[0024] The first injection nozzle 61 and the second injection nozzle 62 are configured to be movable in the radial direction by an injection nozzle moving mechanism 63. Specifically, as shown in FIGS. 1 and 3, the first injection nozzle 61 and the second injection nozzle 62 are fixed on a support base 64. The support base 64 is connected to a rod of the injection nozzle moving mechanism 63. In this embodiment, the injection nozzle moving mechanism 63 is in the form of a hydraulic cylinder, but can be any actuator. When the rod of the hydraulic cylinder strokes radially outward, the first injection nozzle 61 and the second injection nozzle 62 can move together in the radial direction. The first injection nozzle 61 and the second injection nozzle 62 can move to the outside in the radial direction beyond the outer edge portion in the radial direction of the cutter head portion 30 through a notch portion 34 (see FIG. 3) formed on the side surface of the cutter head portion 30.

[0025] According to the above-described tunneling machine 10, ground improvement can be performed by the following procedure. First, the cutter head portion 30 is arranged at a predetermined rotational angle position according to a desired ground improvement target range. Typically, the predetermined rotational angle position is a position where the first injection nozzle 61 and the second injection nozzle 62 are located at the uppermost part, as shown in FIG. 1. Next, a mud material is supplied into the chamber 24 from at least one of the plurality of second through holes 42. As a result, only the periphery of the at least one second through hole 42 among the excavated soil in the chamber 24 becomes a fluidized state (shown as a fluidized range 71 in FIG. 4).

[0026] Next, as shown in FIG. 4, with the first injection nozzle 61 positioned inside the radially outer edge portion of the cutter head portion 30, a ground improvement material is injected obliquely forward from the first injection nozzle 61 to perform ground improvement of the ground improvement range 72. At this time, since the ground improvement material is injected in excess, the injected ground improvement material returns into the chamber 24 together with the soil replaced by the ground improvement material. For this reason, only the valve 43 provided in the at least one second through hole 42 (the second through hole 42 used for the supply of the mud material) among the plurality of second through holes 42 is opened, and mud is discharged from the chamber 24 to the internal space 25 through the at least one second through hole 42. FIG. 4 exemplarily shows a state where mud is discharged from three second through holes 42 (however, only one of the two second through holes 42 arranged symmetrically on the left and right is shown). Since only the periphery of the at least one second through hole 42 (that is, the fluidized range 71) used for the supply of the mud material is fluidized, the ground improvement material and the soil that have returned into the chamber 24 are quickly taken into the internal space 25 without spreading throughout the chamber 24 (while suppressing movement downward from the fluidized range 71). Thereby, solidification of the ground improvement material in the chamber 24 can be suppressed. In the present embodiment, the ground improvement material and the soil that have returned into the chamber 24 are first stored in a mud discharge tank 45 through a pipe 44 connected to the valve 43, and then conveyed rearward.

[0027] Next, as shown in FIG. 5, the first injection nozzle 61 is moved to the outside of the radially outer edge portion of the cutter head portion 30. In the present embodiment, while moving the first injection nozzle 61, fluid is injected from the second injection nozzle 62 in the moving direction of the first injection nozzle 61. Thereby, the ground on the moving path of the first injection nozzle 61 can be agitated, and as a result, the movement of the first injection nozzle 61 can be smoothed. In an alternative embodiment, the first injection nozzle 61 may be moved after the injection of fluid from the second injection nozzle 62. When the first injection nozzle 61 is moved a predetermined distance, a ground improvement material is injected from the first injection nozzle 61 to improve the ground improvement range 73 located above the ground improvement range 72. Also at this time, mud is discharged in the same manner as when improving the ground in the ground improvement range 72. In an alternative embodiment, while moving the first injection nozzle 61 to the outside of the radially outer edge portion of the cutter head portion 30, at the same time, a ground improvement material may be injected from the first injection nozzle 61. Also in this case, fluid may be injected from the second injection nozzle 62 while moving the first injection nozzle 61, or the first injection nozzle 61 may be moved after the injection of fluid from the second injection nozzle 62.

[0028] Next, as shown in FIG. 6, the first injection nozzle 61 is further moved to the outside of the radially outer edge portion of the cutter head portion 30. Also at this time, fluid is injected from the second injection nozzle 62 in the moving direction of the first injection nozzle 61. When the first injection nozzle 61 is further moved a predetermined distance, a ground improvement material is injected from the first injection nozzle 61 to improve the ground improvement range 74 located above the ground improvement range 73. Also at this time, mud is discharged in the same manner as when improving the ground in the ground improvement range 72.

[0029] According to the above-described tunneling machine 10, the first injection nozzle 61 can be moved radially outward beyond the radially outer edge of the cutter head portion 30, and the ground improvement material can be jet-injected at high pressure from the first injection nozzle 61 after the movement. Therefore, the range in which ground improvement can be performed can be expanded radially. Also, as in the above-described embodiment, by moving the first injection nozzle 61 a plurality of times stepwise and jet-injecting the ground improvement material from the first injection nozzle 61 at each movement position, the range in which ground improvement can be performed can be further expanded radially.

[0030] Moreover, since the first injection nozzle 61 jet-injects the ground improvement material at high pressure in a direction angled radially outward with respect to the rotation axis AX, the range in which ground improvement can be performed can be further expanded radially compared to a configuration in which the first injection nozzle 61 jet-injects the ground improvement material at high pressure in a direction parallel to the rotation axis AX.

[0031] Also, according to the tunneling machine 10, when jet-injecting the ground improvement material from the first injection nozzle 61, sludge discharge can be performed through the second through-hole 42 located above the first through-hole 41 instead of the first through-hole 41 for taking in excavated soil into the machine interior space 25. Therefore, compared to the case of performing sludge discharge through the first through-hole 41, the movement range of the ground improvement material and soil that has returned into the chamber 24 within the chamber 24 can be limited. As a result, the ground improvement material and soil that have returned into the chamber 24 can be quickly taken into the machine interior space 25, and solidification of the ground improvement material within the chamber 24 can be suppressed.

[0032] As described above, the embodiments of the present invention have been explained. However, the above-described embodiments of the invention are for facilitating the understanding of the present invention and do not limit the present invention. The present invention can be changed and improved without departing from its gist, and equivalents of the present invention are included therein. Also, within the range that can solve at least a part of the above-described problems or within the range that exhibits at least a part of the effects, any combination or any omission of each component described in the claims and the specification is possible.

[0033] For example, the supply of the mud-added material and / or the mud discharge during the injection of the ground improvement material may be performed using any second through-hole 42 among the plurality of second through-holes 42. Also, the number of the second through-holes 42 can be set to any number of one or more.

[0034] Alternatively, the mud discharge during the injection of the ground improvement material may be performed via at least one second through-hole 42 and the first through-hole 41. Even in this case, compared with the case where the mud discharge is performed only via the first through-hole 41, the movement range within the chamber 24 of the ground improvement material and soil that has returned to the chamber 24 can be limited.

[0035] Alternatively, the configuration for injecting the above-described soil improvement material and the above-described mud discharge method using the second through-hole 42 may be implemented independently of each other.

Explanation of Reference Numerals

[0036] 10...Tunneling machine 20...Tunneling machine body 24...Chamber 25...Inner machine space 30...Cutter head part 32...Spoke 33...Cutting bit 34...Notch part 40...Partition wall 41...First through-hole 42...Second through-hole 43...Valve 44...Pipe 45...Mud discharge tank 50...Main shaft 55...Screw conveyor 61...First injection nozzle 62...Second injection nozzle 63...Injection nozzle movement mechanism 64...Support stand 65...Pipe 71...Fluidization range 72, 73, 74...Ground improvement range AX...Axis of rotation

Claims

1. An excavator, comprising an excavator body, a cutter head portion disposed on the front side in the excavation direction with respect to the excavator body and configured to be rotatable about a rotation axis with respect to the excavator body, a first injection nozzle provided on the cutter head portion and configured to inject a ground improvement material forward in the excavation direction under high pressure, and an injection nozzle moving mechanism configured to move the first injection nozzle in a radial direction with respect to the rotation axis, characterized in that the injection nozzle moving mechanism is configured to move the first injection nozzle to the outside in the radial direction with respect to the outer edge portion of the cutter head portion in the radial direction, said excavator.

2. The excavator according to claim 1, wherein the first injection nozzle is oriented to inject the ground improvement material forward under high pressure in a direction angled outward in the radial direction with respect to the rotation axis, said excavator.

3. The excavator according to claim 1 or claim 2, comprising a second injection nozzle provided on the cutter head portion and configured to inject a fluid forward under high pressure toward the outside in the radial direction in the moving direction of the first injection nozzle, wherein the injection nozzle moving mechanism is configured to move the second injection nozzle together with the first injection nozzle, and the second injection nozzle is configured to inject the fluid when moved to the outside in the radial direction with respect to the outer edge portion of the cutter head portion together with the first injection nozzle or before that, said excavator.

4. The excavator according to claim 1 or claim 2, characterized by a partition wall that divides the inner space of the excavator body into a chamber exposed to the soil and an in-machine space disposed on the rear side in the excavation direction with respect to the chamber and not exposed to the soil, the partition wall having a first through hole located below the rotation axis and a second through hole located above the first through hole, a conveyor for conveying the excavated soil taken from the chamber into the in-machine space through the first through hole rearward in the excavation direction, and a valve for opening and closing the second through hole, characterized in that when injecting the ground improvement material from the first injection nozzle, the valve is opened to enable sludge discharge from the chamber to the in-machine space through the second through hole, said excavator.

5. The excavator according to claim 4, configured to be able to supply a mud material into the chamber from the second through-hole before injecting the ground improvement material from the first injection nozzle Tunneling machine

6. A ground improvement method for performing ground improvement by a tunneling machine disposed underground, comprising: a step of disposing a cutter head portion rotatably disposed with respect to the tunneling machine body at a predetermined rotational angle position on the front side in the tunneling direction with respect to the tunneling machine body; a step of moving an injection nozzle provided in the cutter head portion to the outside in the radial direction with respect to the outer edge portion in the radial direction of the cutter head portion; a step of injecting a ground improvement material toward the front side in the tunneling direction from the injection nozzle located outside the radial direction with respect to the outer edge portion at high pressure A ground improvement method comprising the steps of:

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