JP5230468B2 - Ground improvement device and ground improvement method for shield machine - Google Patents

Description

  The present invention relates to a ground improvement device and a ground improvement method for a shield machine that injects a ground improvement agent from an underground shield machine to a ground near its front.

  In the case of injecting ground conditioner into the ground near the front part of the underground shield machine, it is usually injected from the ground, but in the case of restrictions on securing ground transportation or deep construction, injection from the ground. Is difficult. Therefore, a construction method is known in which injection is performed not from the ground but from an underground shield machine.

  As such a construction method, using a shield machine equipped with a slide hood that is slidably mounted on the outer periphery of a cylindrical shield frame, and a cutter support portion that is movably disposed in the axial direction inside the slide hood, When the cutter support is moved forward, the slide hood is hooked and pushed forward, and then the ground improver is jetted forward from the partition provided on the cutter support to fill the space between the face and the partition. A construction method is known in which only the cutter support portion is retracted in a state where the slide hood is left behind by pressure, and a ground improvement zone is formed inside the slide hood (see Patent Document 1).

JP 2002-155696 A

  In the above construction method, the ground improvement agent can be filled between the partition wall and the face in the inside of the slide hood, but cannot be injected outside the slide hood. For this reason, it is difficult to make the water stoppage of the earth and sand near the outer periphery of the slide hood perfect.

  Therefore, for example, when the above-mentioned shield frame is used as the shield frame of the parent machine (parent shield machine) and the child machine (child shield machine) is started so as to dig out the front ground improvement zone from inside, The child machine was started from the bottom of the slide hood where there was anxiety (pipe bottom start), and the child machine was started from the approximate center position of the slide hood.

  However, in the field of sewage tunnels and the like, it is required to connect a small-diameter tunnel with a slave unit to the bottom of a large-diameter tunnel with a master unit. For this reason, there has been a demand for a construction method that can inject the ground improver not only to the inside of the slide hood but also to the outside soil, and to increase the water-stopping property of the soil near the outer periphery of the slide hood.

  An object of the present invention is to provide a ground improvement device and a ground improvement method for a shield machine capable of accurately injecting a ground improvement agent into the soil inside and outside the slide hood and increasing the water stoppage of the soil near the outer periphery of the slide hood. There is to do.

In order to achieve the above object, a ground improvement device for a shield machine according to claim 1 is disposed on the outer periphery of a shield frame so as to be movable in the axial direction, and is disposed inward of the slide hood. A cutter support portion that is movable in the axial direction with respect to the shield frame, an engagement portion formed on the outer periphery of the cutter support portion, and an inner periphery of the slide hood, and the engagement portion is engaged from behind. An engaged portion for pushing forward the slide hood while preventing the slide hood from rotating, a chemical injection pipe for a ground improvement agent attached to the cutter support portion and having an opening on the outer periphery of the cutter support portion; The slide hood is provided with an injection hole that is formed through and in alignment with the position of the opening of the chemical liquid injection tube when the engagement portion is engaged with the engaged portion. Cutter support A groove formed on the inner periphery of the slide hood along the axial direction, and an abutting surface formed on the front portion in the axial direction of the groove. And an opening formed at the rear portion in the axial direction of the groove, and when the cutter support portion moves forward, the convex portion enters the groove through the opening and contacts the abutting surface. Thus, the slide hood is pushed forward while being prevented from rotating .

The ground improvement device according to claim 2 is provided with a seal that stops water between the outer periphery of the cutter support portion and the inner periphery of the slide hood, and the outer periphery of the cutter support portion in front of the seal. Further, an opening of the chemical solution injection tube is provided.

In the ground improvement device according to a third aspect , the cutter support portion is moved in the axial direction by expansion and contraction of the shield jack.

A ground improvement method according to claim 4 is a ground improvement method using the ground improvement device for a shield machine according to any one of claims 1 to 3 , wherein the cutter support portion is moved forward and the slide is moved. While the hood is pushed forward, the cutter provided on the cutter support portion is rotated to cut the face, and at this time, the engaging portion engages with the engaged portion. And maintaining the positional relationship between the opening of the chemical solution injection tube and the injection hole, and injecting the ground improver radially outward of the slide hood through the chemical solution injection tube and the injection hole. By injecting a ground improver into the front of the partition wall provided by dividing the face side and the inside of the pit into the cutter support part, the cutter support part is moved backward, so that the outer sand and the diameter of the slide hood in the radial direction, Inward and upward The earth and sand in front of the cutter support part is improved with a ground improver.

  According to the present invention, it is possible to accurately inject a soil conditioner into the soil inside and outside the slide hood, and it is possible to increase the water stoppage of the soil near the outer periphery of the slide hood.

It is a sectional side view of the shield machine equipped with the ground improvement apparatus which concerns on one Embodiment of this invention. 2A is a sectional view taken along line IIa-IIa in FIG. 1, FIG. 2B is a sectional view taken along line bb in FIG. 2A, and FIG. 2C is a sectional view taken along line cc in FIG. It is line sectional drawing. It is a sectional side view which shows the first process of the ground improvement method using the said ground improvement apparatus. It is the IV-IV sectional view taken on the line of FIG. It is a sectional side view which shows the next process of the said ground improvement method. It is a sectional side view which shows the next process. It is a sectional side view which shows the next process. It is a sectional side view at the time of making a child machine start a pipe bottom. FIG. 9A is a side sectional view showing a starting cylinder of the slave unit, and FIG. 9B is a sectional view taken along line BB in FIG. 9A. FIG. 9 is a side cross-sectional view of the child machine starting from the tube bottom following FIG. 8.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  1 is a side sectional view of a shield machine equipped with a ground improvement device according to the present embodiment, FIG. 2 (a) is a sectional view taken along line IIa-IIa in FIG. 1, and FIG. 2 (b) is FIG. 2 (a). FIG. 2C is a sectional view taken along the line bb of FIG. 2B, and FIG. 2C is a sectional view taken along the line cc of FIG.

  As shown in FIG. 1, the shield machine 1 includes a cylindrical shield frame 2, a cylindrical slide hood 3 that is attached to the outer periphery of the front portion of the shield frame 2 so as to be movable in the axial direction, and a slide hood 3. A cutter support portion 4 that is disposed inward and is movable in the axial direction with respect to the shield frame 2 is provided.

  The shield frame 2 has a front small diameter portion 2a and a rear large diameter portion 2b having a larger outer diameter. The slide hood 3 has a front thick portion 3a and a rear thin portion 3b having the same outer diameter and a larger inner diameter. The thin portion 3b is slidably mounted on the outer periphery of the small diameter portion 2a of the shield frame 2. Has been. At the front end of the small-diameter portion 2a of the shield frame 2, a seal 5 that stops water between the thin portion 3b of the slide hood 3 is provided in a ring shape along the circumferential direction.

  The cutter support portion 4 includes a cylinder portion 6 that faces the slide hood 3 and the shield frame 2, and a partition wall 7 that partitions the inside of the cylinder portion 6 from the face side and the inside of the pit. A cylindrical seal support 8 is attached and fixed to the outer periphery of the tube portion 6, and a seal that stops water between the outer periphery and the inner periphery of the thin portion 3 b of the slide hood 3 is provided on the outer periphery of the seal support 8. 9 is provided in a ring shape along the circumferential direction.

  On the partition wall 7, a cutter 10 for cutting the face is rotatably supported. The cutter 10 is rotationally driven by a drive mechanism 11 provided in the partition wall 7, and moves in a radial direction from the base cutter 10a having a diameter smaller than the inner diameter of the thick portion 3a of the slide hood 3 and the end of the base cutter 10a. And an extendable cutter 10b for changing the drilling diameter. The base cutter 10a and the extendable cutter 10b are provided with a bit 12 for cutting the face.

  A plurality of rotor blades 13 are attached to the opposite face side of the base cutter 10a with a radial interval, and a plurality of stationary blades 14 are attached to the partition wall 7 at different radial positions from the rotor blade 13. ing. The earth and sand in the cutter chamber 15 between the cutter 10 and the partition wall 7 is agitated by the rotating blades 13 rotated by the rotation of the cutter 10 and the fixed blades 14 fixed to the partition wall 7.

  The partition wall 7 is provided with a soil removal device (screw conveyor or the like) 16 for transferring the earth and sand in the cutter chamber 15 into the mine. In addition, in the case of a muddy water type shield, the earth discharging apparatus 16 becomes a mud pipe and a mud pipe.

  As shown in FIGS. 2A to 2C, the shield machine 1 includes an engagement portion 17 formed on the outer periphery of the cutter support portion 4 and an engaged portion formed on the inner periphery of the slide hood 3. And a joint portion 18.

  The engaging portion 17 includes a convex portion 17 a formed along the axial direction on the outer periphery of the seal support 8 of the cutter support portion 4. The engaged portion 18 has a convex portion 17a engaged from behind (rightward in FIGS. 2B and 2C) to prevent the slide hood 3 from rotating and forward (FIG. 2B). , (C) on the left side), the groove 18a is formed along the axial direction on the inner periphery of the thick portion 3a of the slide hood 3, and is formed in the axial front portion of the groove 18a. It comprises an abutting surface 18b and an open portion 18c formed in the axial rear portion of the groove 18a. The open part 18c is formed on a stepped surface connecting the thick part 3a and the thin part 3b. When the cutter support part 4 moves forward, the convex part 17a enters the groove 18a through the opening part 18c and comes into contact with the abutting surface 18b, whereby the slide hood 3 is prevented from rotating and pushed forward. It is like that.

  A plurality of engaging portions 17 are provided on the outer periphery of the cutter support portion 4 at intervals in the circumferential direction. In accordance with this, the engaged portions 18 are also spaced on the inner periphery of the slide hood 3 in the circumferential direction. A plurality are provided.

  As shown in FIG. 1, the shield machine 1 is formed by penetrating the inner and outer peripheral surface of the slide hood 3 with a chemical injection pipe 20 for a ground improvement agent having an opening 19 on the outer periphery of the cutter support 4. An injection hole 21 is provided.

  The chemical liquid injection tube 20 is attached to the inside of the cylindrical portion 6 of the cutter support portion 4 so as to be inclined obliquely forward, and has an opening 19 on the outer periphery of the seal support 8. The position of the opening 19 is in front of the seal 9. If it is at the rear, an injection hole 21 formed opposite to the opening 19 is disposed behind the seal 9. In this case, groundwater in the natural ground enters the mine through the injection hole 21. Because it ends up. The chemical injection pipe 20 is provided with an on-off valve 22.

  On the other hand, the injection hole 21 matches the position of the opening 19 of the chemical solution injection tube 20 and the axis of the chemical solution injection tube 20 when the convex portion 17a shown in FIG. 2 abuts against the abutting surface 18b of the groove 18a. The slide hood 3 is formed through the thick portion 3a of the slide hood 3 obliquely therethrough.

  A plurality of chemical injection pipes 20 are attached to the cutter support portion 4 at intervals in the circumferential direction, and a plurality of injection holes 21 are also formed in the slide hood 3 at intervals in the circumferential direction.

  As shown in FIG. 1, a side injection pipe 23 for ground improvement agent is attached to the small diameter part 2 a of the shield frame 2 so as to be inclined forward at the same angle as the chemical injection pipe 20. The side injection tube 23 has an opening 24 on the outer periphery of the small diameter portion 2 a of the shield frame 2. The opening 24 is normally covered by the slide hood 3 shown in FIG. 1 and protected from the earth and sand, and when the slide hood 3 is moved forward as will be described later with reference to FIG. Will face. A plurality of the side injection pipes 23 are attached to the shield frame 2 at intervals in the circumferential direction, and an on-off valve 25 is provided for each.

  As shown in FIG. 1, the cutter support portion 4 and the shield frame 2 can be connected and disconnected by an engagement / disengagement mechanism 26. The engagement / disengagement mechanism 26 includes a flange-shaped metal fitting 26 a provided on the inner periphery of the small-diameter portion 2 a of the shield frame 2, and a fastener 26 b such as a bolt nut that fixes the metal fitting 26 a to the back surface portion of the cutter support portion 4. . The cutter support portion 4 is fixed to the shield frame 2 by tightening the fastener 26b, and the cutter support portion 4 is separated from the shield frame 2 by loosening the fastener 26b. The metal fitting 26a may be fixed by welding to the back surface portion of the cutter support portion 4, and the welded portion may be cut out and separated.

  A plurality of shield jacks 27 are attached to the inner periphery of the shield frame 2 at intervals in the circumferential direction. The shield jack 27 moves the shield frame 2 forward by applying a reaction force to a segment (existing segment) 28 assembled in a ring shape by an unillustrated erector (segment assembly device). The shield jack 27 includes a cylinder 29, a rod 30, and a shoe 31. The cylinder 29 is attached to a ring-shaped mounting bracket 32 provided on the inner peripheral surface of the shield frame 2, and the shoe 31 is pressed against the existing segment 28. It is done.

  A tail seal 33 for stopping water between the inner periphery of the shield frame 2 and the outer periphery of the existing segment 28 is provided at the rear portion of the inner periphery of the shield frame 2.

  The ground improvement method using the ground improvement apparatus of the shield machine 1 having the above configuration will be described.

  First, using the shield machine 1 in the form of FIG. 1 described above, a tunnel is constructed by excavating as usual to the ground point to be improved. At this time, the expansion / contraction cutter 10b is fixed with its expansion / contraction position determined so that the tip thereof matches the outer diameter of the slide hood 3. If excavating to the ground improvement point, stop excavation.

  Next, as shown in FIG. 3, the slide hood 3 is prepared before extrusion.

  Specifically, the shield frame 2 and the existing segment 28 are fixed by the fixing bracket 34 to prevent the shield frame 2 from moving backward, and a spacer 35 is attached to the fixing bracket 34 and sandwiched by the shoe 31 of the shield jack 27. Then, a spacer (spacer) 36 is sandwiched between the cylinder 29 of the shield jack 27 and the back surface portion of the cutter support portion 4, and the fastener 26 b of the engagement / disengagement mechanism 26 is loosened to separate the cutter support portion 4 from the shield frame 2. The connection between the cylinder 29 of the shield jack 27 and the mounting bracket 32 of the shield frame 2 is disconnected. Further, a detent mechanism 37 is attached between the cutter support 4 and the shield frame 2.

  As shown in FIG. 3 and FIG. 4, which is a sectional view taken along the line IV-IV, the rotation prevention mechanism 37 is a prismatic rotation prevention rod 37 a extending rearward from the rear end of the cylindrical portion 6 of the cutter support portion 4. And a pressing metal fitting 37b attached to the inner periphery of the shield frame 2 so as to sandwich the anti-rotation rod 37a from the circumferential direction, and holds the cutter support portion 4 so as not to rotate relative to the shield frame 2. is there. A plurality of anti-rotation mechanisms 37 may be installed at intervals in the circumferential direction of the shield frame 2.

  As shown in FIG. 3, a ground conditioner (solidifying agent such as mortar) is injected into the side ground through the chemical solution injection tube 20 and the injection hole 21. Specifically, the on-off valve 22 of the chemical liquid injection pipe 20 is opened, a chemical injection pipe (not shown) is inserted into the inside of the chemical injection pipe 20, and is inserted into the side ground through the injection hole 21 to a predetermined depth. While pulling out the tube, the ground improvement agent is injected into the side ground from the tip of the drug injection tube, and the ground is improved within a predetermined range.

  Next, as shown in FIG. 5, the slide hood 3 is pushed forward.

  Specifically, the shield jack 27 is extended while rotating the cutter 10, and the cutter support portion 4 is pushed forward while the earth and sand in the cutter chamber 15 is discharged into the pit by the earth removing device 16.

  Thereby, as shown in FIGS. 2A to 2C, the engagement portion 17 of the cutter support portion 4 is engaged with the engaged portion 18 of the slide hood 3, that is, the slide hood 3 rotates. Pushed forward while stopped. Therefore, as shown in FIG. 5, the slide hood 3 is not rotated by the rotating cutter 10, but the opening 19 of the chemical solution injection tube 20 provided in the cutter support 4 and the injection provided in the slide hood 3. The positional relationship with the hole 21 is maintained.

  If the slide hood 3 moves forward by a predetermined amount due to the extension of the shield jack 27, the extension of the shield jack 27 is stopped, and the side part is passed through the chemical injection pipe 20 and the injection hole 21 in which the positional relationship is maintained in the above-described procedure. Inject ground improver into the ground. Here, the amount by which the slide hood 3 is advanced (the predetermined amount) is set so that the previous ground improvement range and the current ground improvement range partially overlap.

  Thereafter, by increasing the number of spacers 36 between the cylinder 29 of the shield jack 27 and the back surface portion of the cutter support portion 4, the slide hood 3 is further advanced by the shield jack 27 via the cutter support portion 4. Similarly, the ground improver is injected into the side ground through the injection tube 20 and the injection hole 21. At this time, the water stop between the slide hood 3 and the shield frame 2 is formed by the seal 5 provided on the shield frame 2, and the water stop between the slide hood 3 and the cutter support portion 4 is the cutter support portion 4. The seal 9 provided in

  While the cutter support part 4 is advanced by the shield jack 27 and the slide hood 3 is pushed forward by the cutter support part 4, the cutter 10 is rotated to cut the face. For this reason, when the cutter support portion 4 receiving the counter torque from the face is about to rotate, the rotation prevention mechanism 37 suppresses the rotation. The anti-rotation rod 37 a of the anti-rotation mechanism 37 is appropriately added as the slide hood 3 advances.

  If the rear end of the slide hood 3 has advanced further forward than the opening 24 of the side injection tube 23, the ground improver is injected from the side injection tube 23 into the side ground. Specifically, the on-off valve 25 of the side injection tube 23 is opened, a drug injection tube (not shown) is inserted into the inside of the side injection tube 23, inserted into the side ground, to a predetermined depth, and the drug injection tube is pulled out. However, the ground improvement agent is injected into the side ground from the tip of the drug injection tube, and the ground is improved within a predetermined range. As a result, the ground in the vicinity of the connecting portion between the slide hood 3 and the shield frame 2 is solidified, and water intrusion from the connecting portion between the slide hood 3 and the shield frame 2 is prevented.

  The ground improvement range by the side injection tube 23 partially overlaps with the ground improvement range that was initially performed. Therefore, all the ground improvement ranges performed so far are partially overlapped, and an integrated ground improvement zone A is formed on the outer periphery of the slide hood 3 so as to cover all of them.

  Next, as shown in FIG. 6, a ground improvement agent is injected in front of the partition wall 7.

  Specifically, the front end of the shield frame 2 and the rear portion of the slide hood 3 are welded and fixed (welded portion 38), the slide hood 3 is prevented from moving backward, and the telescopic cutter 10b is drawn inward in the radial direction. In this state, the cutter 10 is rotated, and the soil improver is injected forward from the partition wall 7, and the earth and sand in the cutter chamber 15 is discharged into the pit by the earth removing device (screw conveyor) 16. Replace with ground improvement agent. Completion of the replacement is confirmed by discharging the ground improver from the earth removing device 16 into the mine. Of course, the partition wall 7 is provided with a soil conditioner injection pipe (not shown).

  Next, as shown in FIG. 7, the ground improvement agent is injected in front of the cutter 10, and only the cutter support portion 4 is moved backward without moving the position of the slide hood 3.

  Specifically, a ground improvement agent is injected forward from the cutter 10, the ground improvement agent is filled between the face and the cutter 10, and the cutter 10 is moved backward by the pressure. At this time, as shown in FIGS. 2 (a) to 2 (c), the convex portion 17 a of the engaging portion 17 provided in the cutter support portion 4 is formed in the groove 18 a of the engaged portion 18 provided in the slide hood 3. The slide hood 3 is left behind, and only the cutter support part 4 is retracted, because the slide hood 3 is left behind from the inside of the groove 18a through the open part 18c (FIG. 2B, right side in FIG. 2C).

  Specifically, the pressure of the ground improving agent filling between the face and the cutter 10, that is, the injection pressure of the ground improving agent and the thrust of the shield jack 27 are synchronized, and the cutter supporting portion 4 is moved backward at a stable speed. Then, by sequentially removing the spacers 36, the cutter support 4 is retracted to a predetermined position (for example, the first position in FIG. 3). As a result, a ground improvement zone B is formed between the partition wall 7 and the face face inside the slide hood 3.

  The water stop between the retracting cutter support 4 and the slide hood 3 left behind is formed by a seal 9 provided on the cutter support 4. The cutter 10 may or may not be rotated when the cutter support portion 4 is retracted by the filling pressure of the ground improvement agent. Of course, the cutter 10 is provided with a ground improver injection pipe (not shown).

  In the process of pushing the slide hood 3 forward by the above procedure, the ground improvement zone A can be formed on the outer periphery of the slide hood 3, and in the process of retracting only the cutter support part 4 without moving the position of the slide hood 3. The ground improvement zone B can be formed inside the slide hood 3. Thus, since the ground improvement zones A and B can be formed inside and outside the slide hood 3, not only can the water stoppage of the earth and sand in front of the cutter support portion 4 in the slide hood 3 be improved, but also the vicinity of the outer periphery of the slide hood 3. It can also increase the water-stopping property of earth and sand.

  Next, as shown in FIG. 8, the procedure for setting the shield frame 2 as a shield frame of a parent machine (parent shield machine) and starting the pipe bottom of the child machine (child shield machine) 40 from the inside will be described.

  First, after the cutter support portion 4 and the shield frame 2 are fixed by a welding or engagement / disengagement mechanism 26 to prevent the cutter support portion 4 from moving backward, the shield jack 27, the earth removing device 16, and the cutter drive mechanism 11 are removed. Carry to the tunnel entrance side (see Figure 7). Thereafter, the bottom of the partition wall 7 is cut into a circle, and a part of the front cutter 10 is also cut according to the shape of the hole, and the starting cylinder 41 is installed there.

  The excavable wall 42 is installed in the front part inside the start cylinder 41. As the material of the excavable wall 42, for example, a material obtained by reinforcing a thermosetting resin foam (hard urethane resin) with glass fiber (FFU: fiber Reinforced Foamed Urethane) is used. The load (earth / water pressure) applied to the opening of the starting cylinder 41 from the ground improvement zone B can be supported only by the excavable wall 42, but a temporary earth retaining 43 is installed behind it for the sake of safety.

  The temporary earth retaining wall 43 supports the excavable wall 42 from behind, and as shown in FIGS. 9 (a) and 9 (b), a plurality of horizontal members (H steel) arranged at intervals in the vertical direction. ) 43a, a plurality of vertical members (H steel) 43b arranged at intervals in the left-right direction, and a diagonal member 43c having one end connected to the horizontal member 43a or the vertical member 43b and the other end connected to the starting cylinder 41. Have The cross member 43a has its front face in contact with the back surface of the excavable wall 42 and spans left and right in the start cylinder 41, and the vertical member 43b has its front face in contact with the back face of the cross member 43a and vertically in the start cylinder 41. It is stretched over. The cross member 43a and the vertical member 43b may be interchanged.

  Thereafter, as shown in FIG. 8, a ring-shaped entrance seal 44 is attached to the rear portion of the starting cylinder 41, and a reaction force receiving member 45 for receiving the propulsive force of the slave unit 40 is attached to the fixing bracket 34. And the starting stand 46 is installed in the bottom part of the shield frame 2 used as a main | base station, and the subunit | mobile_unit 40 is assembled on it. The subunit | mobile_unit 40 is comprised from the cylindrical shield frame 47, the partition 48, the cutter 49, the cutter drive mechanism 50, the earth removal apparatus 51, the shield jack 52, the tail seal 53, an erector (not shown), etc.

  When the assembly of the slave unit 40 is completed, the temporary earth retaining 43 is disassembled and removed. The temporary earth retaining wall 43 supports the excavable wall 42 while assembling the child machine 40 and prevents its breakage. That is, even if the strength of the excavable wall 42 temporarily decreases during the assembly of the slave unit 40 due to vibration associated with the assembly, the temporary earth retaining wall 43 that supports the excavable wall 42 exists behind the excavable wall 42. The excavable wall 42 is not damaged by being pushed by soil water pressure. The temporary earth retaining 43 is preferably installed when the operation of assembling the child device 40 in the shield frame 2 of the parent device is prolonged, and can be omitted.

  Thereafter, as shown in FIG. 10, the child machine 40 is started from the inside of the shield frame 2 of the parent machine, and the excavable wall 42 is dug by the cutter 49 of the child machine 40, and the small diameter is formed at the bottom of the large diameter tunnel. Will be built by connecting the tunnels. Thus, even if the child machine 40 is started from the bottom of the pipe from the inside of the parent machine, in this embodiment, the ground improvement zones A and B are formed inside and outside the slide hood 3 of the parent machine, Since the water-stopping property of the earth and sand in the vicinity of the outer periphery of the slide hood 3 is enhanced, the inundation into the mine does not become a problem.

  The present invention is not limited to the above embodiment.

  For example, after forming the ground improvement zones A and B inside and outside the slide hood 3 as shown in FIG. 7, the bit 12 of the cutter 10 of the parent machine may be replaced instead of starting the pipe bottom of the child machine 40. .

DESCRIPTION OF SYMBOLS 1 Shield machine 2 Shield frame 3 Slide hood 4 Cutter support part 7 Bulkhead 9 Seal 10 Cutter 17 Engagement part 17a Protrusion part 18 Engaged part 18a Groove 18b Abutting surface 18c Open part 19 Opening 20 Chemical solution injection pipe 21 Injection hole 27 Shield jack A Ground improvement zone radially outward of the slide hood B Ground improvement zone radially inward of the slide hood and in front of the cutter support

Claims (4)

A slide hood attached to the outer periphery of the shield frame so as to be movable in the axial direction;
A cutter support portion disposed inward of the slide hood and movable in the axial direction with respect to the shield frame;
An engaging portion formed on the outer periphery of the cutter support portion;
An engaged portion that is formed on the inner periphery of the slide hood and engages the engagement portion from the rear so as to push the slide hood forward while preventing rotation.
A chemical injection pipe for a ground improvement agent attached to the cutter support part and having an opening on the outer periphery of the cutter support part;
The slide hood is provided with an injection hole penetratingly formed in accordance with the position of the opening of the chemical solution injection tube when the engagement portion is engaged with the engaged portion ,
The engaging portion is composed of a convex portion formed on the outer periphery of the cutter support portion,
The engaged portion is formed in a groove formed along the axial direction on the inner periphery of the slide hood, an abutting surface formed in an axial front portion of the groove, and an axial rear portion of the groove. Consisting of an open part,
When the cutter support part moves forward, the convex part enters the groove through the opening part and comes into contact with the abutting surface, so that the slide hood is pushed forward while being prevented from rotating.
This is a ground improvement device for a shield machine. Provided on the outer periphery of the cutter support portion is a seal that stops water between the outer periphery and the inner periphery of the slide hood,
The ground improvement device for a shield machine according to claim 1 , wherein an opening of the chemical solution injection pipe is disposed on an outer periphery of the cutter support portion in front of the seal. The ground improvement device for a shield machine according to claim 1 or 2 , wherein the cutter support portion is moved in the axial direction by expansion and contraction of a shield jack. A ground improvement method using the ground improvement device for a shield machine according to any one of claims 1 to 3 ,
While moving the cutter support portion forward and pushing the slide hood forward, the cutter provided on the cutter support portion is rotated to cut the face.
At that time, the engaging portion engages with the engaged portion to prevent the slide hood from being swung, and the positional relationship between the opening of the chemical solution injection tube and the injection hole is maintained.
Injecting the ground improver radially outward of the slide hood through the chemical solution injection tube and the injection hole,
After that, by injecting a ground improvement agent in front of the partition wall provided by dividing the face side and the pit inner side into the cutter support part, the cutter support part is moved backward,
A ground improvement method characterized in that the soil outside the radial direction of the slide hood and the soil inside the radial direction and in front of the cutter support portion are improved with a ground improvement agent.

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