JP2006029079A - Recovery method of guiding pipe in small diameter jacking machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recovery method of a guiding pipe in a small diameter jacking machine capable of advancing boring again by inputting the guiding pipe recovered in a buried pipe laid in advance or a new guiding pipe, by easily recovering its guiding pipe to the starting shaft side via the inside of the laid buried pipe, by accurately jacking the guiding pipe, by reducing jacking resistance to soil of a wide range such as a base rock layer from a gravel layer. <P>SOLUTION: A cutter head 6 is diametrally contracted, and after releasing the connection between the guiding pipe C and an outer cylinder A put in a connecting state when laying the buried pipe 2, a protective wall is made by retreating by a predetermined quantity by applying pulling-back force to the guiding pipe C, while injecting chemicals into the front of the guiding pipe C, by using a screw conveyor for discharging sediment, and afterwards, the guiding pipe C is recovered via the inside of the outer cylinder A and the inside of the buried pipe 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for collecting a leading conduit in a small-diameter propulsion device that pulls back and collects the leading conduit provided in the small-diameter propulsion device.

  As a conventional small-diameter propulsion device, a propulsion device having a leading conduit in which a cutter head is rotatably attached to a front end portion of a trunk portion having substantially the same outer diameter as a buried pipe is used. When laying a buried pipe with this small-diameter propulsion machine, the cutter head is rotated, and a propulsion device installed in advance in the starting shaft is pressed against the rear end of the leading conduit to extend it to the leading conduit. Transmit propulsive force and penetrate the conduit into the natural ground. Next, the propulsion device is contracted to connect the buried pipe to the rear end portion of the leading conduit, and the propelling device is pressed against the rear end portion of the buried pipe and extended to thereby exert a propelling force on the leading conduit via the buried tube. introduce. By repeating this, the buried pipes are sequentially connected and the buried pipes are laid. When the laying operation of the buried pipe is completed in this way, only the leading conduit exposed to the reaching shaft is recovered from the reaching shaft. In addition, when the direction of the leading conduit deviates from the planned laying line during propulsion, the direction is generally corrected by swinging the leading conduit.

  However, in such a small-diameter propulsion machine, the leading conduit cannot be collected until it reaches the reaching shaft, so if the reaching shaft cannot be constructed due to the circumstances around the location where the buried tube is laid, The problem that cannot be done.

  As a method for solving such a problem, in Patent Document 1 and Patent Document 2, the outer diameter of the leading pipe is made smaller than the inner diameter of the buried pipe, and the leading pipe is recovered through the buried pipe to the start shaft. Small caliber propulsion machines have been proposed.

  However, in the small-diameter propulsion devices disclosed in these Patent Documents 1 and 2, since the outer diameter of the leading conduit is smaller than the inner diameter of the buried pipe, the portion outside the inner diameter of the buried pipe is not excavated. The buried pipe will be propelled, and the ground outside the inner diameter of the buried pipe will be consolidated, resulting in a problem that the propulsion resistance will increase and the construction efficiency will decrease.

  As a countermeasure against such a problem, Patent Document 3, Patent Document 4 and Patent Document 5 describe that the excavating diameter of the leading pipe is substantially the same as the outer diameter of the buried pipe, and that the leading pipe is connected to the buried pipe. There has been proposed a small-diameter propulsion device configured to be able to be recovered on the start shaft side through the buried pipe while avoiding interference.

  In the small-diameter propulsion device 100 described in Patent Document 3, as shown in FIG. 6, the crushing bit 101 is held by a holding member 102 and is swingably attached to an outer tube 103 by a hinge 104. The wedge-shaped slider 106 inserted between the rear end portion of the holding member 102 of the crushing bit 101 and the outer tube 103 is provided at the tip of the inner tube 107 by moving the inner tube 105 forward. It has been. The crushing bit 101 is supported in a state where the wedge-shaped slider 106 is completely inserted and opened to the outside, and the crushing bit 101 is unsupported by moving the inner cylinder 105 rearward. . The small-diameter propulsion device 100 is configured to be pulled back to the start shaft side with the support of the crushing bit 101 being released. Further, the small-diameter propulsion device 100 is configured such that the entire inner cylinder 105 rotates and the excavated material is taken in from the opening 108 on the front surface.

  As shown in the front view of FIG. 7, the small-diameter propulsion device 110 described in Patent Document 4 is provided with an outer cylinder 113 on the outer periphery of a tip conduit 112 provided with a cutter head 111 on the front surface. 112 and the outer cylinder 113 are connected by a shear pin that is sheared when a shearing force of a predetermined value or more is applied. The outer diameter of the cutter head 111 is smaller than the inner diameter of the outer cylinder 113, and the earth and sand in front of the outer cylinder 113 is not excavated by the cutter head 111, but the diameter of the outer peripheral surface of the outer cylinder 113 increases toward the tip. The tapered surface is adapted to be pierced into the ground when propulsive force is applied, and the earth and sand are introduced into the leading conduit 112. In addition, after the excavation by the small-diameter propulsion device 110 is completed, the shear pin is sheared by the pulling force applied to the tip conduit 112, the connection between the outer cylinder 113 and the tip conduit 112 is released, and the tip conduit 112 is It is pulled back through the tube 113.

  As shown in FIG. 8, the small-diameter propulsion device 120 described in Patent Document 5 has an outer peripheral bit 121 attached to the tip, and a plurality of spokes 122 that can be refracted toward the excavation surface are arranged in the radial direction. The cutter head 123 is composed of a cutter head 123, a tip conduit 124 on which the cutter head 123 is rotatably mounted on the front surface, and an outer cylinder 125 disposed on the outer periphery of the tip conduit 124, and the outer periphery when the cutter head 123 is rotated. The trajectory of the bit 121 is set to be substantially equal to the outer diameter of the outer cylinder 125, and the leading conduit 124 and the outer cylinder 125 are connected via shear pins (not shown) that are sheared when a shearing force of a predetermined value or more acts. Connected.

  In this small-diameter propulsion device 120, the pulling force is transmitted to the leading conduit 124 after the excavation is completed, the shearing force acting on the shear pin is increased, and when the predetermined value is reached, the shear pin is sheared and the outer cylinder 125 and the leading conduit are The connection with 124 is released. Thereafter, the tip of the spoke 122 comes into contact with the end of the outer cylinder 125, and the spoke 122 is refracted toward the excavation surface side by the subsequent pulling back of the leading pipe 124, thereby avoiding interference with the outer cylinder 125 and passing through the outer cylinder 125. Pulled back.

Utility Model Registration No. 2537753 Utility Model Registration No. 2559261 Japanese Patent Laid-Open No. 7-269284 JP-A-8-284140 JP-A-9-144485

  However, in the small-diameter propulsion device 100 described in Patent Document 3, since the entire inner cylinder 105 rotates and cannot be bent, the direction cannot be corrected, and accurate construction is difficult. is there. In addition, since the excavated earth and sand are directly taken in from the opening 108, there is a problem that it cannot be pulled back into the start shaft when the earth and sand are stored in the inner cylinder. In addition, there is no means to support the earth pressure in front of the cutter, and it is not possible to cope with construction in a stagnant water layer or highly disintegrating soil.

  In addition, in the small-diameter propulsion device 110 described in Patent Document 4, the outer cylinder 113 is propelled so that the tip of the outer cylinder 113 is inserted into a natural ground. For example, the rocker or the gravel layer is robust. There is a problem that it is difficult to propel the outer cylinder 113 for the formation. Further, the shear pin connecting the front conduit 112 and the outer cylinder 113 is sheared to pull back the front conduit 112, and therefore, the front conduit 112 cannot be inserted into the outer cylinder 113 again to dig up.

  On the other hand, in the small-diameter propulsion device 120 described in Patent Document 5, since the earth and sand are excavated by the outer peripheral bit 121 attached to the spoke 122, it is difficult to excavate the gravel layer. There is. Further, the shear pin that connects the leading conduit 124 and the outer cylinder 125 is sheared to separate the leading conduit 124 and the outer casing 125 so that the leading conduit 124 is pulled back. The problem is that it is impossible to re-insert / re-extrude the leading conduit 124 because it cannot be inserted and connected to the outer cylinder 125 again, and the refracted spoke 122 cannot be expanded with respect to the face. There is.

  The present invention has been made to solve such a problem, and it is possible to propel the leading pipe with a small amount of propulsion resistance and with high accuracy with respect to a wide range of soil properties such as a gravel layer to a rock layer. Small diameter that can be easily recovered to the start shaft side through the buried pipe where the conduit is laid, and can be re-excavated by introducing the previously collected conduit or a new leading conduit into the previously laid underground pipe An object of the present invention is to provide a method for recovering a leading conduit in an excavator.

In order to achieve the above object, a method for recovering a leading conduit in a small diameter propulsion device according to the first invention comprises:
In the outer cylinder connected to the tip of the buried pipe and having an outer diameter substantially the same as the outer diameter of the buried pipe, the outer diameter becomes substantially the same as the outer diameter of the buried pipe when the diameter is expanded, and from the inner diameter of the buried pipe when the diameter is reduced. In a small-diameter propulsion device that collects a leading pipe through a buried pipe laid by using a small-diameter propulsion machine in which a leading pipe having a small outer diameter and an expandable / contractable cutter head is connected and separable. In the recovery method of the first conduit,
After reducing the diameter of the cutter head and releasing the connection between the front pipe and the outer cylinder, which are in a connected state when the buried pipe is laid, forward to the front pipe using a screw conveyor for discharging earth and sand While a chemical solution is being injected, a pulling back force is applied to the tip conduit to retract it by a predetermined amount to create a protective wall, and then the tip conduit is recovered through the outer cylinder and the buried tube.

In addition, the recovery method of the tip conduit in the small diameter propulsion device according to the second invention is as follows:
In the outer cylinder connected to the tip of the buried pipe and having an outer diameter substantially the same as the outer diameter of the buried pipe, the outer diameter becomes substantially the same as the outer diameter of the buried pipe when the diameter is expanded, and from the inner diameter of the buried pipe when the diameter is reduced. In a small-diameter propulsion device that collects a leading pipe through a buried pipe laid by using a small-diameter propulsion machine in which a leading pipe having a small outer diameter and an expandable / contractable cutter head is connected and separable. In the recovery method of the first conduit,
The diameter of the cutter head is reduced, and after releasing the connection between the front conduit and the outer cylinder that are in a connected state when the buried pipe is laid, the tip of the outer cylinder reaches the tip position of the cutter head. Pushing the outer cylinder and the buried pipe, and then injecting a chemical solution to the front of the leading conduit, applying a pulling force to the leading conduit to retract a predetermined amount to create a protective wall, then inside the outer cylinder and the buried pipe And recovering the leading conduit through.

  According to the first invention, after the laying of the buried pipe is completed, the leading conduit can be pulled back and collected, so that the reaching shaft that has been conventionally required for collecting the leading conduit becomes unnecessary, thereby reducing the cost and the construction period. be able to. In addition, the leading pipe can be pulled back, and can be inserted into the underground outer cylinder to resume the laying operation of the buried pipe. Even if it occurs, it is not necessary to construct an intermediate shaft or the like, and it is possible to carry out repair work of the leading conduit and removal work of underground obstacles. Also, when the tip conduit is pulled back, a chemical solution is injected into the cavity formed by this pulling back to form a protective wall. Therefore, even if it is a spring ground or a strong collapsible ground, the buried pipe should be laid securely. It is possible to recover the end pipe and adapt to a wider range of soil quality. In addition, there is an effect that the outer cylinder and the buried pipe can be accurately propelled with a small propulsion resistance.

  According to the second invention, in addition to having the same effect as the first invention, the outer cylinder and the buried pipe are propelled forward when the leading conduit is pulled back, so that the hollow portion generated by pulling back the leading conduit is covered in advance. Furthermore, since a protective wall is formed by injecting a predetermined amount of chemical solution while retreating the previous conduit, for example, even in spring ground or strong collapse ground, it is possible to reliably lay the buried pipe and collect the previous conduit In addition, since the chemical solution injection section can be shortened, the construction period can be shortened and the cost can be reduced.

  Next, a specific embodiment of a method for recovering a leading conduit in a small diameter propulsion device according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a longitudinal sectional view of a leading conduit of a small bore propulsion device according to a first embodiment of the present invention. FIG. 2 shows a cross-sectional view taken along the line PP in FIG.

  The small-diameter propulsion device 1 of the present embodiment has an outer diameter A that is substantially the same as the outer diameter of the buried pipe 2 and is connected to the tip of the buried pipe 2, and can be connected to and separated from the outer cylinder A. It is configured by a leading conduit C and a propulsion device (not shown) that is disposed in a start shaft not shown and presses the rear end surface of the buried pipe 2 to apply a thrust to the leading conduit C.

  The front conduit C has a body portion 3 having an outer diameter smaller than the inner diameter of the buried tube 2 and the outer cylinder A, and the body portion 3 is divided into a front body 3a and a rear body 3b. The barrel 3b is swingably connected to the swinging portion 4 by a swinging jack (not shown), and has a structure capable of correcting the propulsion direction. A cutter head 6 having a plurality of disc cutters 5 on the front surface is provided in front of the front barrel 3a in the propulsion direction, and dirt and the like are externally provided between the bulk head 7 at the rear of the cutter head 6 and the disc cutter 5. An intake chamber 8 is provided. The cutter head 6 is rotatably supported with respect to the front cylinder 3a by a cutter head driving portion 6a provided in the front cylinder 3a. In FIG. 1, the front conduit C of the small-diameter propulsion machine 1 is illustrated as being divided into two front and rear parts.

  In the trunk portion 3, a soil discharging device 9 that discharges the earth and sand taken into the chamber 8 is provided so as to penetrate the trunk portion 3 to the rear of the rear barrel 3 b slightly along the central axis. The earth removal device 9 includes a screw conveyor 10 and a casing 11 thereof. A screw shaft 12 of the screw conveyor 10 is rotatable forward and backward around an axis by a drive motor 13 attached to a rear end thereof.

  The disc cutter 5 disposed on the outer peripheral portion of the cutter head 6 is supported by the tip end portion of a support member 14 having a substantially L-shaped cross section that is pivotally supported by a bracket 15 protruding forward from the bulk head 7. It is swingable from a position substantially the same as the outer diameter of the outer cylinder A to a position slightly on the center side from the inner diameter of the outer cylinder A. The front surface of the bulkhead 7 is located on the base end side from the corner portion of the support member 14 when the diameter of the cutter head 6 is expanded, that is, when the disk cutter 5 is swung to the same position as the outer diameter of the outer cylinder A. A stopper 16 is provided for holding the position of the disk cutter 5 by contacting the back surface. When the support member 14 is not in contact with the stopper 16 at the outermost part of the front surface of the stopper 16, there is a tunnel wall between the rear surface of the base end portion of the support member 14 and the bulkhead 7. A gravel biting prevention rubber 17 is provided so as to prevent the gravel from entering.

  On the front surface of the cutter head 6, there is provided an expansion / contraction mechanism D for operating the swing of the disk cutter 5 to expand / contract the outer diameter of the cutter head 6. The expansion / contraction mechanism D projects radially and radially from a slide case 20 in which the disk cutter 5 can swing back and forth along the outer periphery of a shaft 19 disposed at the center of the front surface of the cutter head 6. A link member 22 is pivotally supported by the bracket 21 to be linked. That is, when the slide case 20 is slid forward, a pressing force is applied to the disk cutter 5 toward the radially outer side of the cutter head 6 via the link member 22, and the outer diameter of the cutter head 6 is enlarged. (Indicated by the solid line in FIG. 1). On the other hand, when the slide case 20 is slid rearward, a drawing force is applied to the disk cutter 5 inward in the radial direction of the cutter head 6 via the link member 22, and the outer diameter of the cutter head 6 is reduced. (Indicated by a two-dot chain line in FIG. 1).

  The slide case 20 is connected to the front end of the screw shaft 12 via a ball joint 20a, and only the movement of the screw shaft 12 in the front-rear direction is transmitted to the slide case 20 by the ball joint 20a. The rotation speed difference between the rotation of the screw shaft 12 and the rotation of the screw shaft 12 is allowed.

  The rear end portion of the casing 11 of the earth removing device 9 is divided into front and rear, and the casing portion on the rear side is fitted to the casing portion on the front side so as to be slidable back and forth. A slide case sliding jack 23 is mounted across the divided portion. Accordingly, the extension of the slide case sliding jack 23 pulls the screw shaft 12 backward, and the contraction of the slide case sliding jack 23 pushes the screw shaft 12 forward.

  The rear portion of the casing 11 is connected to a soil discharge pipe 24 connected to the excavated soil transporting space between the screw shaft 12 and the casing 11. A suction side pipe 26 provided with a vacuum pump P1 for discharging the waste water and a delivery side pipe 27 provided with a pressure feed pump P2 for sending filler to the front surface of the cutter head 6 through the excavated earth and sand space are connected. This filler is a one-component type solidifying agent whose curing time is adjusted so as to cure after reaching the front of the cutter head 6 through the excavated earth and sand space.

  A pair of upper and lower propulsive force transmission members 30a and 30b made of a substantially arc-shaped plate material are provided at the rear end of the rear barrel 3b. As shown in FIG. 2, one ends of these propulsive force transmitting members 30 a and 30 b are pin-coupled to each other so as to be rotatable, and the other ends are connected to each other via a jack 31. The propulsive force transmission members 30a and 30b are configured to expand and contract in the radial direction.

  Further, when the thrust transmission members 30a and 30b are expanded in diameter at the rear inner circumference of the outer cylinder A and at the corresponding positions of the thrust transmission members 30a and 30b, the outer circumferences of the thrust transmission members 30a and 30b. An engaging member 33 having an engaging groove 32 for engaging the portion is fixed. In this way, the outer cylinder A and the rear cylinder 3b are connected and buried by extending the jack 31 and expanding the propulsive force transmitting members 30a and 30b and engaging the outer peripheral portions thereof with the engaging grooves 32. By pushing the rear end surface of the tube 2 and applying a driving force, the driving force is applied to the leading conduit C. Further, when the jack 31 is contracted and the propulsive force transmitting members 30a, 30b are reduced in diameter, the outer peripheral portions of the propulsive force transmitting members 30a, 30b are disengaged from the engaging grooves 32, and the outer cylinder A and the rear trunk The connection with 3b is released.

  In order to lay the buried pipe 2 using the small-diameter propulsion device 1 configured as described above, first, the leading pipe C is inserted into the outer cylinder A, and the slide case sliding jack 23 is contracted to screw the screw shaft 12. Is pushed forward to move the slide case 20 forward, thereby pushing out the disk cutter 5 in the radial direction of the cutter head 6 and expanding the diameter of the cutter head 6. Next, the outer cylinder A and the leading conduit C are integrated by engaging the engaging groove 32 of the engaging member 33 by expanding the propulsive force transmitting members 30a and 30b. In this way, with the front cutter head 6 rotated, the rear end surface of the outer cylinder A is pressed by the propulsion device installed in the start shaft, and a propulsive force is applied to the leading conduit C. Excavation is performed with substantially the same diameter as the diameter, and the outer cylinder A penetrates into the ground.

  Next, the buried pipe 2 is connected to the rear end surface of the outer cylinder A, and if the rear end face of the buried pipe 2 is pressed by the propulsion device, the propulsive force is transmitted to the front conduit C via the buried pipe 2 and the outer cylinder A. Then, excavation work is performed. In this way, new buried pipes 2 are successively added to the rear end surface of the buried pipe 2 and the excavation work is repeated to lay the buried pipe 2. During excavation work, the earth discharge pipe 24 is connected to the suction side pipe 26 by the switching valve 25, and the earth and sand taken into the chamber 8 is rotated in the forward direction of the screw conveyor 10 and the earth and sand discharge space of the earth removal device 9 is discharged. Then, it is supplied to the soil discharge pipe 24 and is sucked into the suction side pipe 26 by the operation of the vacuum pump P1.

  Next, after the excavation work (laying work of the buried pipe 2) by the small-diameter propulsion device 1 is completed, or the excavation work is interrupted, a recovery procedure for recovering the leading conduit C to the start shaft side will be described. .

  FIG. 3 is an explanatory diagram for explaining a procedure for recovering the leading conduit C of the first embodiment to the start shaft.

  In the present embodiment, when the excavation work (laying operation of the buried pipe 2) by the small-diameter propulsion machine 1 is completed and the leading conduit C is collected in the starting shaft, or the excavating work is interrupted and the leading conduit C is moved to the starting shaft. 3 (FIG. 3A), first, the slide case 20 is moved backward by extending the slide case slide jack 23 and sliding the screw shaft 12 backward, so that the disc cutter 5 is pulled toward the center in the radial direction of the cutter head 6 to reduce the outer diameter of the cutter head 6 so as to be smaller than the inner diameter of the outer cylinder A (FIG. 3B).

  Next, the jack 31 is contracted to reduce the diameter of the propulsion force transmitting members 30a and 30b, the connection between the outer cylinder A and the leading conduit C is released, and then the leading conduit C is pulled back to the start shaft side. Simultaneously with the withdrawal of the leading conduit C, the switching valve 25 is connected to the delivery side pipe, the screw conveyor 10 is rotated in the reverse direction, and the filler is sent forward of the cutter head 6 (FIG. 3C).

  With this filler, after the cavity formed by the retreat of the leading conduit C and the tip in the outer cylinder A are solidified (FIG. 3 (d)), the pump is stopped and the filler is injected. At the end, the leading conduit C is pulled back and collected in the starting shaft (FIG. 3 (e)).

  According to this embodiment, since the hollow part formed by the retreat of the front conduit C and the tip part of the outer cylinder A are blocked by the filler, it is reliably constructed even in a spring ground or a strong collapse ground. It is possible to achieve the effect of being able to cope with a wider range of soil quality.

  Further, according to the present embodiment, since the excavation work is performed by the disc cutter 5 disposed on the front surface of the cutter head 6, it is possible to cope with a wide range of soil properties such as gravel and rock, and the cutter head 6 Since excavation is performed with a diameter substantially equal to the outer diameter of the cylinder A, the outer cylinder A and the buried pipe 2 can be propelled with a small propulsion resistance and with high accuracy. Further, since the leading conduit C is recovered in a reusable state, the recovered leading conduit C can be reintroduced into the outer cylinder A and re-digged.

  In addition, according to the present embodiment, the leading conduit C can be collected in the start shaft while being reusable. For example, when exchanging the disk cutter 5 during excavation work, or during excavation, excavation is impossible. When an obstacle appears, the leading conduit C can be once recovered in the start shaft, and the leading conduit C can be put in again after the cutter steel pipe work or the obstacle removing work is completed, and the re-digging can be performed.

  In the present embodiment, when the diameter of the cutter head 6 is increased during the excavation work, the connection between the leading conduit C and the outer tube A is performed. The diameter of the cutter head 6 may be increased after A is connected, and the connection between the leading conduit C and the outer cylinder A and the diameter of the cutter head 6 may be simultaneously performed.

Further, in the present embodiment, the outer cylinder A and the buried pipe 2 that have been disconnected from the leading conduit C by the propulsion device are propelled forward, but not limited to this, a schematic configuration is shown in FIG. As shown in the figure, the outer cylinder A has a double cylinder structure, the inner cylinder A ₁ is pushed forward by a slide jack 35 provided in the outer cylinder A ₂ , and the tip of the inner cylinder A ₁ is shown. You may make it a part become the same position as the front-end | tip part of the tip conduit C. In this case, the stroke of the slide jack 35 is not set as the required slide amount, but is pushed out by sequentially adding the spacers 36 with a short stroke.

  In the present embodiment, a one-component type solidifying agent is used as the filler. However, the present invention is not limited to this. For example, a two-component mixed type solidifying agent can also be used. In this case, for example, the screw shaft 12 is hollow, and one chemical liquid of the two-liquid mixing type is supplied to the front of the cutter head 6 through the screw shaft 12, and the other chemical liquid is supplied to the cutter head through the excavated sediment discharge space. The two chemicals may be mixed in front of the cutter head 6 and cured.

  Next, a method for collecting the leading conduit according to the second embodiment of the present invention will be described. In the present embodiment, there is no difference from the first embodiment except only the procedure for recovering the leading conduit C to the starting shaft. Hereinafter, parts common to the first embodiment will be described using the same reference numerals.

  Next, a method for recovering the leading conduit according to the second embodiment of the present invention will be described with reference to FIG. In the present embodiment, there is basically no difference from the first embodiment except that the configuration for injecting the filler into the cutter head 6 and the configuration of the outer cylinder A ′ are different. Therefore, parts common to the first embodiment will be described using the same reference numerals.

  In the small-diameter propulsion device 1 ′ of the present embodiment, a filler channel pipe 40 is attached to a part of the outer periphery of the outer cylinder A ′ (lower part in the present embodiment) and from the front end portion to the rear end portion. The filler is injected into the front of the cutter head 6 through the filler channel pipe 40. The rear portion of the filler channel pipe 40 is disposed in the buried pipe 2, and the tip of the filler channel pipe 40 is communicated with the tip of the outer cylinder A ′. Note that it is not necessary to provide the switching valve 25 on the downstream side of the soil discharge pipe 24, and the soil discharge pipe 24 only needs to be connected to the suction side pipe 26 provided with the vacuum pump P1.

  Further, the outer cylinder A ′ is provided with an outer cylinder of the small-diameter propulsion device 1 used in the first embodiment in order to secure a length for pulling back the leading conduit C while injecting the filler from the filler channel pipe 40. It is set longer than A.

  In the present embodiment, as shown in FIG. 5, when the excavation work by the small-diameter propulsion device 1 ′ is completed by the same procedure as in the first embodiment or is interrupted, the leading conduit C is moved to the start shaft side. When pulling back (FIG. 5 (a)), the disk cutter 5 is first retracted toward the center in the radial direction of the cutter head 6 to reduce the outer diameter of the cutter head 6 to be smaller than the inner diameter of the outer cylinder A ′ (FIG. 5). (B)). Next, the jack 31 is contracted to reduce the propulsive force transmission members 30a and 30b, the connection between the outer cylinder A and the front conduit C is released, and the front end surface of the outer cylinder A is connected to the front end surface of the front conduit 2. The outer cylinder A and the buried pipe 2 are pushed forward until they are substantially in the same position (FIG. 5C).

  Next, while moving the leading conduit C rearward, the filler is sent through the filler flow passage pipe 40 from the front end portion of the outer cylinder A to the front of the cutter head 6 and from inside the tunnel face to the inside of the outer cylinder A. After the filler is injected into the tip space to form a protective wall (FIG. 5 (d)), the injection of the filler is terminated, the leading conduit C is pulled back and collected in the starting shaft (FIG. 5 ( e)).

  According to the present embodiment, substantially the same effect as the first embodiment can be obtained. Moreover, since the injection amount of the filler can be reduced, the cost can be reduced and the construction period can be shortened. Moreover, since the said filler flow path piping 40 is provided in the outer peripheral part of outer cylinder A ', and miniaturization of the tip conduit C is attained, it can apply to laying of a buried pipe with a still smaller diameter.

  In the present embodiment, the leading conduit C is pulled back while injecting the filler into the front of the cutter head 6 from the filler channel pipe 40, but this is not limiting, and the same small diameter as in the first embodiment. It is also possible to pull back the leading conduit C in the above procedure while injecting the filler by reverse rotation of the screw shaft 12 using the propulsion device 1.

  In each of the above embodiments, the connection between the leading conduit C and the outer cylinder A is released after the cutter head 6 has been reduced in diameter, but this is not restrictive, and the connection between the leading conduit C and the outer casing A is released. After that, the cutter head 6 may be reduced in diameter, or the connection between the leading conduit C and the outer cylinder A and the diameter reduction of the cutter head 6 may be performed simultaneously.

The longitudinal cross-sectional view of the tip conduit | pipe of the small diameter propulsion apparatus which concerns on the 1st Embodiment of this invention PP sectional view of FIG. Explanatory drawing explaining the collection | recovery procedure of the front conduit of 1st Embodiment Explanatory drawing explaining another method of propelling the outer cylinder forward Explanatory drawing explaining the collection | recovery procedure of the front conduit of the 2nd Embodiment of this invention Longitudinal cross-sectional view of the tip conduit of a conventional small-diameter propulsion machine Top view of the tip of a conventional small-diameter propulsion machine Longitudinal cross-sectional view of the tip conduit of a conventional small-diameter propulsion machine

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Small caliber propulsion machine 2 Buried pipe 3 Trunk part 3a Front trunk 3b Rear trunk 4 Oscillating part 5 Disc cutter 6 Cutter head 6a Cutter head drive part 7 Bulkhead 8 Chamber 9 Earth removal apparatus 10 Screw conveyor 11 Casing 12 Screw shaft 13 Drive motor 14 Support member 15 Bracket 16 Stopper 17 Gravel biting prevention rubber 19 Shaft 20 Slide case 21 Bracket 22 Link member 23 Slide case slide jack 24 Drain pipe 25 Switching valve 26 Suction side pipe 27 Send side pipe 30a, 30b Thrust transmission Member (connecting means)
31 Jack 32 Engagement groove 33 Engagement member 35, 41 Slide jack 36, 42 Spacer 40 Filling material passage piping A Outer cylinder C End conduit D Expansion / contraction mechanism

Claims (2)

In the outer cylinder connected to the tip of the buried pipe and having an outer diameter substantially the same as the outer diameter of the buried pipe, the outer diameter becomes substantially the same as the outer diameter of the buried pipe when the diameter is expanded, and from the inner diameter of the buried pipe when the diameter is reduced. In a small-diameter propulsion device that collects a leading pipe through a buried pipe laid by using a small-diameter propulsion machine in which a leading pipe having a small outer diameter and an expandable / contractable cutter head is connected and separable. In the recovery method of the first conduit,
After reducing the diameter of the cutter head and releasing the connection between the front pipe and the outer cylinder, which are in a connected state when the buried pipe is laid, forward to the front pipe using a screw conveyor for discharging earth and sand A small-diameter propulsion device that applies a retracting force to the tip conduit while injecting a chemical solution to make a protective wall by retreating by a predetermined amount, and then collects the tip conduit through the outer tube and the buried tube For collecting the first conduit in In the outer cylinder connected to the tip of the buried pipe and having an outer diameter substantially the same as the outer diameter of the buried pipe, the outer diameter becomes substantially the same as the outer diameter of the buried pipe when the diameter is expanded, and from the inner diameter of the buried pipe when the diameter is reduced. In a small-diameter propulsion device that collects a leading pipe through a buried pipe laid by using a small-diameter propulsion machine in which a leading pipe having a small outer diameter and an expandable / contractable cutter head is connected and separable. In the recovery method of the first conduit,
The diameter of the cutter head is reduced, and after releasing the connection between the front conduit and the outer cylinder that are in a connected state when the buried pipe is laid, the tip of the outer cylinder reaches the tip position of the cutter head. Pushing the outer cylinder and the buried pipe, and then injecting a chemical solution to the front of the leading conduit, applying a pulling force to the leading conduit to retract a predetermined amount to create a protective wall, then inside the outer cylinder and the buried pipe The tip conduit is recovered through the small diameter propulsion device.

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