JP2005240509A - Flexible small-diameter jacking pipe, and jacking method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-diameter flexible jacking pipe which minimizes bending of its flexible portion at the time of jacking the pipe, and to provide a jacking method which is applicable to the small-diameter flexible jacking pipe in which intra-pipe work cannot be carried out, and facilitates installation work. <P>SOLUTION: The flexible small-diameter jacking pipe is formed of a jacking pipe body 1 and the flexible portion 2, and a rigid pipe 30 is detachably fitted and fixed into the jacking pipe body 1 in an axial direction so as to be astride the flexible portion 2. Thus by inserting the rigid pipe 30 into the jacking pipe body 1 from one end and locating the rigid pipe so as to be astride the flexible portion 2, the rigid pipe can be easily installed in the small-diameter flexible jacking pipe without carrying out the intra-pipe work. Further if the flexible portion 2 is inclined to bend at the time of jacking the pipe, the bending inclination is suppressed by a rigid force of the rigid pipe 30. Furthermore only by drawing the rigid pipe 30 from the one end of the flexible jacking pipe after completion of the propulsion, the former can be easily detached from the latter through simple operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small-diameter propulsion pipe having a flexible portion and a propulsion method thereof.

  In recent years, a fume pipe is generally used as a sewer pipe of a natural flow type. However, in a buried pipe using the fume pipe, the fume pipe cannot cope with bending or eccentricity caused by uneven settlement of the ground or an earthquake. Even if a part of the fume tube is broken or even if it does not lead to breakage, a defect or a ring-shaped crack may occur at the end of the fume tube, and external water may enter from that part. In order to cope with such damage, a fume tube having a flexible part is used. For example, Japanese Utility Model Publication No. 59-22389 can be mentioned.

  This has two cylinders with metal flanges facing each other outward, with a required distance between the two flanges arranged at opposite positions, and the inner end and the cylindrical part. Covering the upper surface with cylindrical rubber and coating rubber, providing a flexible part in which two cylinders with a metal collar part are integrated by vulcanization, and a plurality of anchor bolts on the outside of the collar part It is integrated with the fume tube. This flexible fume tube has a feature that when a large external force acts on the fume tube due to uneven settlement of the ground or an earthquake, the flexible part can easily follow to prevent the fume tube from being damaged. . However, since the flexible portion is made only of cylindrical rubber, handling of the fume tube after pipe making is troublesome. In other words, it is essential to lift and unload the fume tube during storage, transportation and installation. It may be bent (refracted / bent) and the lifting position may shift and come off.

Further, when a flexible fume tube is laid by the propulsion method, if the thrust during propulsion deviates from the axis of the fume tube, the fume tube may be bent at the flexible portion. If it bends, it will affect the propulsion (increase in thrust), and if the propulsion is finished while it is bent, there is a problem that the original flexibility is lost. In severe cases, bending of the flexible part may cause the bent part to collide with the tunnel ground and become impossible to propel.
In addition, when the direction is corrected by the excavator, there is a case where a large bending stress acts on the flexible portion of the leading flexible propelling tube. If the flexible portion is bent due to this stress, the direction of the excavator is corrected. Absorbing, the subsequent propulsion pipe will not follow correctly, and as a result, impossibility of propulsion may occur.

  Therefore, a flexible propulsion tube improved from the above-described technique, that is, a structure in which the flexible portion 2 is integrally formed at the intermediate portion in the longitudinal direction of the concrete portion 4 of the propulsion tube 1 as shown in FIG. The applicant has proposed.

The flexible part 2 bisects the concrete part 4 of the propelling tube 1 and the steel ring 5 integrated on the outer peripheral surface of the concrete part 4 in the length direction, and opposes the bisected concrete part 4. The elastic ring 11 is interposed between the end faces, the elastic ring 11 has outward elastic flanges 12 at both ends, and the inward steel flange 6 is provided on the inner peripheral surface of the steel ring 5. The steel flange 6 is applied to the inner side of the elastic flange 12, the presser ring 15 is applied to the outer side of the elastic flange 12, and the elastic flange 12 is clamped and fixed to each steel flange 6. Are respectively integrated, the opposing end faces of the thrust receiving rings 7 are butted against each other, the opposing end faces of the inner circumferential thrust receiving rings 16 integrally provided with the holding rings 15 are butted together, A thrust transmission ring 17 is interposed between the clamp 6 and the presser ring 15, and the elastic flange 12 is clamped and fixed between the steel flange 6 and the presser ring 15 with bolts and nuts 8. The grout material 20 is filled between the rings 11 from the injection port 19. On the inner peripheral surface of the inner peripheral thrust receiving ring 16, a stainless steel ring 18 over the concrete portion 4 on both sides thereof is integrally provided. Further, a required number of reinforcing steel plates 25 are attached to the inner peripheral surface of the stainless steel ring 18, and bolts 27 are screwed into nuts 26 embedded in the concrete portion 4 to be detachably attached. The reinforcing steel plate 25 has a function to reinforce the flexible portion 2 so as not to bend during conveyance of the flexible propulsion tube and to suppress bending during propulsion. In addition, the reinforcement steel plate 25 is made to loosen and remove the bolt 27 after the end of propulsion (see, for example, Patent Document 1).
JP 2000-35169 A

  However, the attachment of the reinforcing steel plate 25 is an operation by tightening the bolts 27 in the propulsion tube 1 and uses the required number of reinforcing steel plates 25, which is troublesome. Since the bolt 27 is removed after the propulsion 25 is removed, the number of operations increases, and as a result, a large-diameter flexible propulsion tube that allows a person to enter the propulsion tube 1 and perform the operation. There is a problem that it is limited to the caliber. In addition, since the required number of reinforcing steel plates 25 is used, the reinforcing effect may not be sufficient for bending of the flexible portion due to thrust during propulsion, and a thick steel plate must be used to enhance this effect. There is.

  The present invention has been made to improve the above-described problem, and suppresses bending of the flexible portion during propulsion and enables application to a flexible propulsion tube having a small diameter that cannot be operated in the tube. And it makes it a subject that attachment work is easy.

In order to solve the above-described problems, the present invention provides a flexible small-diameter propulsion tube having a flexible portion in the propelling tube body, and is rigid across the flexible portion in the axial direction in the propulsion tube body. The tube was detachably fitted and fixed.
That is, since the rigid tube is inserted into the propulsion tube from one end side and positioned across the flexible portion, the rigid tube can be easily converted into a flexible propulsion tube having a small diameter without performing an in-pipe operation. Can be attached to. Further, if the flexible portion is to be bent by the rigid tube during propulsion, the bending is suppressed by the rigid force of the rigid tube. Furthermore, after completion of the propulsion, the rigid tube can be easily removed by simply pulling it out from one end of the flexible propulsion tube, and the operation is easy.

Moreover, the structure which extended the said rigid pipe to the back | inner side across the said flexible part from the one end side of the said propelling pipe body was employ | adopted.
According to the above configuration, since it is only necessary to fit the rigid tube to the propelling tube body from one end side, the mounting operation is easy and greatly labor-saving, and it is effective for small diameter pipes that cannot be operated in the tube. is there.
Moreover, when the flexible small-diameter propelling pipe is propelled by receiving a propelling force, if the propelling force deviates from the axial center of the propelling pipe, the flexible portion tends to bend by the deflected propelling force. The bending is restrained by the rigid force of the rigid tube, and propulsion is smoothly performed by this restraining action.

  In addition, by adopting a configuration in which an outward flange is provided on one end side of the rigid tube, the rigid strength of the rigid tube is increased, the circularity is maintained, and the bending restraining force of the flexible portion is further enhanced. Moreover, it functions as a stopper when fitted to a flexible small-diameter propelling tube.

  In addition, by adopting a configuration in which a gap is provided between the propulsion tube and the rigid tube, and a spacing member is detachably attached to the gap from both ends of the rigid tube, the rigid tube is fitted to the propulsion tube. The fitting is easy, and after the fitting, the gap holding member provides a uniform gap, so that the bending of the flexible portion is eliminated.

  In addition, the flexible small-diameter propulsion pipe is used as a pipe near the head or a pipe near the tail, and after the pipe near the head or the tail is buried in the ground by a propulsion method, the flexible small-diameter pipe is used. The propulsion method was used to remove the rigid tube from the propulsion tube. The leading pipe is a propulsion pipe connected next to the leading pipe or / and the leading pipe, and the trailing pipe is a propulsion pipe connected in front of the trailing pipe or / and the tail pipe. That is. According to this propulsion method, in the propulsion process, the flexible portion tries to bend by receiving the propulsive force deflected, but the bending is suppressed by the rigid force of the rigid tube. Moreover, by removing the rigid tube after the propulsion is completed, the original function of the flexible portion is exhibited, and the flow cross-sectional area of the flexible small-diameter propelling tube is not reduced and can be reused. .

As described above, since the rigid pipe extending beyond the position of the flexible portion is detachably fitted in the flexible small-diameter propulsion pipe, the present invention can be used in the propulsion process of the propulsion pipe. When the bending portion is bent by receiving the propelling force deflected, the refraction can be suppressed by the rigidity force of the rigid tube, and the propulsion can be smoothly performed by the suppressing action.
In addition, the propulsion pipe can be easily handled, and the deformation of the flexible portion during propulsion can be restricted to prevent a decrease in water stoppage.
Furthermore, since the rigid tube only needs to be fitted to the propelling tube from one end, its mounting workability and removal work during propulsion are greatly reduced, and it is particularly effective for small diameter pipes that cannot be internally operated. It is.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same code | symbol is used for the same member as a prior art example. 1 and 2 show a flexible small-diameter propulsion pipe according to the first embodiment. The flexible small-diameter propulsion pipe is a length of a propulsion pipe body 1 made of a reinforcing steel-containing centrifugal concrete pipe (fume pipe). Middle part of the direction, that is, the concrete part 4 of the propelling tube 1 is divided into two in the length direction at a predetermined interval, and the flexible part 2 is interposed between the divided concrete parts 4 and integrated. It is.
Steel rings 5 are integrally provided on the outer peripheral surfaces of the concrete parts 4 on both sides so as to cover the outer peripheral surface of the flexible part 2, and the opposing end surfaces of the steel rings 5 on both sides are flexible parts 2. Is faced in the middle. An inward steel flange 6 is fixed to the inner peripheral surface of each steel ring 5 by welding, and an outer peripheral thrust receiving ring 7 that receives thrust on the inner peripheral surface of each steel ring 5 or the inner surface of the steel flange 6. Are integrally provided by welding.

Each outer circumferential thrust receiving ring 7 has a required strength plate thickness to transmit the thrust, and the opposed end faces are butted at the same position as the butting position of the steel ring 5. A predetermined number of fixing bolts and nuts 8 are inserted into the steel flanges 6 from the inner surface side, and the bolt heads 9 are fixed to the steel flanges 6 by welding.
The elastic ring 11 which is a constituent member of the flexible portion 2 is entirely made of rubber, and is provided with outward elastic flanges 12 at both ends, and an extension margin portion 13 which is bent and deformed outwardly in an inverted U shape at an intermediate portion thereof. Provided.
The steel flange 6 is applied to the inner surface of the elastic flange 12 via a rubber seal 14 and the fixing bolt / nut 8 is inserted.

A presser ring 15 is applied to the outer surface of each elastic flange 12. The presser ring 15 reaches the vicinity of the outer peripheral portion of the concrete portion 4, and a stainless steel ring 18 is integrally provided on the inner surface on the inner peripheral side, closer to the inner diameter side than the elastic ring 11. The opposing end faces of the stainless steel ring 18 are abutted at the same positions as the abutting positions of the steel ring 5 and the outer circumferential thrust receiving ring 7. However, the stainless steel ring 18 does not directly transmit thrust.
In addition, by making the said ring 18 from stainless steel materials, for example, while protecting from the corrosion by the flowing water of the holding ring 15 by a general steel material, the elastic ring 11 is also protected.

Further, a thrust transmission ring 17 is integrally provided by welding on the inner surface on the outer peripheral side of the presser ring 15, and the thrust transmission ring 17 faces the outer surface of the steel ring 6.
The fixing bolt / nut 8 is also inserted into the presser ring 15, and by fastening the nut 8, the elastic flange 12 is fixed by crimping between the steel flange 6 and the presser ring 15. The thrust transmission ring 17 contacts the steel flange 6 in a state where the elastic flange 12 is crimped.
An injection port 19 provided in the steel ring 5 and the outer circumferential thrust receiving ring 7 in the space formed by the outer circumferential surface of the elastic ring 11, both outer circumferential thrust receiving rings 7 and both steel flanges 6. The grout material 20 is injected and filled.

The flexible small-diameter propulsion pipe has the above-described configuration. When this is manufactured, first, an assembly in which the outer peripheral thrust receiving ring 7 and the steel flange 6 are integrated with the steel ring 5 is preliminarily provided. The fixing bolt 8 is fixed to the steel flange 6, and the opposite end surfaces of the steel ring 5 and the outer peripheral thrust receiving ring 7 of another assembly similarly configured are abutted. Next, the elastic flange 12 of the elastic ring 11 is placed along the outer peripheral surface of the steel flange 6 on both sides via the sealing material 14, and the fixing bolt 8 is inserted into the bolt hole of the elastic flange 12. On the other hand, an assembly comprising the presser ring 15, the stainless steel ring 18 and the thrust transmission ring 17 is manufactured in advance, the presser ring 15 is placed along the outer peripheral surface of the elastic flange 12, and the fixing bolt 8 is attached to the bolt hole of the presser ring 15. And is fastened with nut 8. At this time, the elastic flange 12 is held in a predetermined compressed state. Thereafter, a grout material 20 such as a fast-strength non-shrink mortar is injected and filled from the injection port 19. Thereby, a ring-shaped flexible part assembly is formed as a whole.
The above flexible part assembly is set in a cylindrical frame of a centrifugal molding machine (not shown) together with a reinforcing bar, concrete is put in by a conventional method, and the flexible part assembly is integrated and integrated with the concrete to be flexible. A small-diameter propulsion pipe.

  In the flexible small-diameter propelling tube formed as described above, a rigid tube 30 extending from one end side (the insertion port 1b side in FIG. 1) to the receiving port 1a across the flexible portion 2 is fitted. An outward flange 31 provided on one end side of 30 is brought into contact with the end surface of the pipe body 1 with a cushion material 32 interposed therebetween.

In the first embodiment, the other end of the rigid tube 30 extends to the receiving port 1a of the propelling tube 1. However, the rigid tube 30 does not have to be the entire length as long as it straddles the flexible portion 2 (elastic ring 11). Moreover, although the steel material is used as the material, a rigid resin material may be used.
The flange 31 increases the rigidity strength, that is, the circularity of the rigid tube 30, and abuts against the end of the propelling tube 1, thereby fulfilling the stopper function of the rigid tube 30. In addition, 33 is a screw for forming 2-4 pieces on the same circumference.

  3 to 5 show a second embodiment, in which the rigid tube 30 is slightly extended from the one end side (the insertion port 1b side in FIG. 1) to the back side across the flexible portion 2 in the propelling tube 1. It is fitted. In the first embodiment, the clearance S between the outer diameter of the rigid tube 30 and the inner diameter of the propulsion tube 1 is omitted because it is the minimum necessary for fitting. The predetermined gap S is set in consideration of the inner surface accuracy, the processing accuracy of the rigid tube 30, and the detachability of the rigid tube 30. The clearance S allows the rigid tube 30 to be easily fitted into the propulsion tube 1, but conversely, the shaft center of the propulsion tube 1 and the shaft center of the rigid tube 30 are displaced due to the weight of the rigid tube 30. The flexible part may be bent during propulsion.

  Therefore, a tapered distance piece 34 (four in the illustrated example) that is a spacing member is driven into the clearance S between the outer peripheral surface of the distal end (back) side end of the rigid tube 30 and the inner peripheral surface of the propelling tube 1. The tool 35 is used for driving so that the axial centers of the propulsion tube 1 and the rigid tube 30 coincide with each other. On the other hand, a spacing member is also provided at the base end (flange 31 side) of the rigid tube 30. This spacing member is formed near one end of the rigid tube 30, so that a set bolt 37 is screwed into a screw 36 (3 to 4 pieces) and its tip is brought into contact with the inner surface of the propelling tube 1. Thereby, both axial centers of the propelling tube 1 and the rigid tube 30 are made to coincide. Thereby, the rigidity of the flexible part 2 is maintained.

Further, instead of the interval holding member having a structure in which the set bolt 37 is screwed into the rigid tube 30, as shown in FIG. 6, 3 to 4 embedded nuts 39 are embedded on the inner surface of the end portion of the propelling tube 1, The rigid tube 30 can be concentric with the propulsion tube 1 by passing the rigid tube 30 through the nut 39 and screwing the fixing bolt 40.
Further, by setting the rigid tube 30 in the flexible small-diameter propulsion tube at the factory, the flexible portion 2 does not bend when the flexible small-diameter propulsion tube is lifted and suspended.

  In the propulsion method using the flexible small-diameter propulsion pipe (referred to as the top pipe Pa) with the rigid pipe 30 shown in FIG. 3, first, the excavator (semi-shield machine) B is started as shown in FIG. The excavator B is suspended from the pit A, and the excavator B is pushed by the hydraulic jack C, and the excavator B is driven to excavate the natural ground. Connected to the cylinder B1, the rear end of the front pipe Pa is applied to the contact plate B2, and the front pipe Pa is pushed by the hydraulic jack C while being excavated by the excavator B in the same manner as described above, and propulsion is performed. Further, a propulsion pipe Pb that does not have a flexible portion is connected to the leading pipe Pa for propulsion, and subsequent propulsion pipes Pb are sequentially connected for propulsion to lay a propulsion pipeline. When the leading pipe Pa comes close to the front manhole D or the reaching pit, a flexible small-diameter propelling pipe (rear tail pipe) is connected to the propelling pipe Pb on the rear side, and further propulsion, the leading pipe Pa becomes as shown in FIG. As shown in Fig. 2, the propulsion work is finished when the opening of the front manhole D is reached and the tail pipe is located in the start shaft A (not shown).

  Thereafter, the rigid tube 30 is pulled out from the top tube Pa. The rigid tube 30 is pulled out by removing the propulsion unit B from the top tube Pa from the manhole D side, and further loosening the set bolt 37 and then screwing the extraction bolt 38 into the female screw 33 as shown in FIG. When the pipe 30 is slightly pulled out from the top pipe Pa (see FIG. 9A), the driven distance piece 34 is loosened (see FIG. 9B). Thereafter, the rigid tube 30 is extracted by a drawing tool (not shown), and the distance piece 34 remaining in the top tube Pa is also taken out by hand or using a scraping jig (not shown). In FIG. 8, Pc is a small-diameter propulsion pipe (rear tail pipe) having flexibility 2, and the rigid tube 30 is fixedly attached to the rear tail pipe Pc, and the removal thereof is from the relationship of the propulsion direction. This is done from the rear end of the tail tube.

  In the above configuration, the thrust applied to the receiving port 1a of the flexible small-diameter propulsion pipe is applied to the presser ring 15, the thrust transmission ring 17, the steel flange 6 and the outer peripheral side thrust receiving ring at the outer peripheral portion of the flexible portion 2. 7 is transmitted to the insertion port 1b through the butted end face. In addition, since the grout material 20 has the compressive strength of an axial direction, while bearing a part of thrust transmission, watertightness is exhibited by close_contact | adherence with the steel flange 6. FIG.

  If the thrust to the flexible small-diameter propelling tube deviates from the axial direction during the above-described propulsion process, the flexible portion 2 tends to bend. At this time, the external force to be bent is supported by the rigid force of the rigid tube 30, and the bending of the flexible portion 2 is suppressed, so that smooth propulsion is performed.

After the propulsion is completed, the flexible portion 2 exhibits its original flexibility function by removing the rigid tube 30. That is, when ground fluctuation or the like occurs in the underground pipe constructed by the embedded flexible small-diameter propulsion pipe, the concrete part 4 on the receiving port 1a side and the concrete part 4 on the insertion port 1b side are connected to the flexible part. The abutting surfaces of the steel ring 5 and the outer circumferential thrust receiving ring 7 are displaced in the shearing direction or deformed according to an external force such as a V shape or an inverted V shape. Further, the expansion margin 13 of the elastic ring 11 is also elastically deformed or extended according to the above-described deformation, causing the propulsion pipe itself to be lost or cracking, so that a seal between the ground and the inside of the pipe is obtained. To maintain.
In addition, after the propulsion, the rigid tube 30 is removed from the propulsion tube 1, so that the fluid passage cross-sectional area of the propulsion tube 1 is not reduced and a predetermined flow rate is ensured. Further, the removed rigid tube 30 is reused.

10 to 11 show a third embodiment, in which a rigid tube 30 is mounted across the flexible portion 2 and slightly longer than the length of the flexible portion 2. In this case, a spacing member (tapered distance piece) 34 is driven into the gap S between the propelling tube 1 and the rigid tube 30 from both sides of the rigid tube 30 using a driving jig 35, and the rigidity of the propelling tube 1 and the rigid tube 30 is increased. Both axial centers of the tube 30 are matched. Both of the attachment positions of the spacing member 34 are within the propelling tube 1, but if a long driving jig 35 is used, it can be easily mounted from the outside of the propelling tube 1, and even when it is removed, it is long. Can be easily removed by using the hook jig. In addition, as the tube length of the rigid tube 30 is short, the tube thickness is increased to maintain the rigidity.
In this embodiment, the thrust is received only by the outer peripheral thrust receiving ring 7 and the inner peripheral thrust receiving ring 16 is omitted. Reference numeral 18 denotes a stainless steel ring that protects the flexible portion 2.

  FIG. 12 shows another example of the thrust receiving ring, in which an inner peripheral thrust receiving ring 16 is provided instead of the outer peripheral thrust receiving ring 7. That is, an inner peripheral thrust receiving ring 16 is integrally provided on the inner diameter side of the elastic ring 11 between the presser rings 15 and the opposed end faces of the inner peripheral thrust receiving ring 16 are abutted against each other. Thereby, the thrust is borne only by the inner circumferential thrust receiving ring 16. That is, the thrust is transmitted to the insertion port 1b side through the butting end surfaces of the presser ring 15 and the inner peripheral thrust receiving ring 16 in the inner peripheral portion of the flexible portion 2.

  Further, a stainless steel ring 18 extending over the concrete portion 4 on both sides of the inner peripheral side thrust receiving ring 16 can be arranged and welded to the presser ring 15 to be integrated. Thereby, the steel ring 6, the inner peripheral thrust receiving ring 16 and the elastic ring 11 made of general steel are protected from the inside. Other members that are the same as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

The start pit A is usually constructed by driving a sheet pile, and this sheet pile is often at a position away from a manhole to be installed later. The reason is that the manhole is considerably smaller than the start pit A. For this reason, the propulsion pipe located at the position of the sheet pile is often a pipe in front of the last tail pipe connected to the manhole A, and a flexible small-diameter propulsion pipe may be used for this pipe.
The sheet pile driven into the ground to construct this start pit A is removed after the propulsion construction of the propulsion pipe. In this case, the sheet pile located in the upper part of the propulsion pipe is easily pulled out by fusing at the upper part of the propulsion pipe, but the sheet pile at the lower part of the propulsion pipe cannot be pulled out and removed due to the existence of the buried pipe. is there. For this reason, when an earthquake or ground subsidence occurs, the flexible propulsion tube positioned on the remaining sheet pile is resistant to the bending of the flexible portion 2 even if bending or shearing force acts on the sheet pile as a fulcrum. Folding and breakage are suppressed.
In addition, although the manhole D was shown in the above example on the arrival side of the propulsion pipe, there is a case where an arrival mine using a sheet pile is constructed in the same manner as the above-described start pit A. In this case, a flexible propelling tube may be used next to the leading tube depending on the distance between the sheet pile and the manhole to be installed.

The position of the flexible portion 2 is about 0.3 to 0.6 m from the side wall of the manhole when the tube length L of the flexible small diameter propulsion tube is 1.0 to 1.2 m, and the tube length L = 2. If it is 0 to 2.43 m, it is provided 0.5 to 1.2 m from the side wall of the manhole.
In addition, a small diameter is a thing with a pipe diameter of 250 mm-700 mm in which a person cannot enter and work in a propulsion pipe.

1 is a partially cutaway sectional view showing a flexible small-diameter propulsion pipe according to a first embodiment of the present invention. Partially enlarged sectional view of FIG. Partially cutaway sectional view showing a second embodiment of the present invention AA line arrow view of FIG. FIG. 3 shows details of FIG. 3, (a) is a partially enlarged sectional view of a connected state with an excavator, and (b) is an enlarged sectional view of (a). Partially cutaway sectional view showing a modification of the first embodiment according to the present invention Schematic explanatory diagram showing the propulsion state of the present invention Schematic explanatory diagram showing the state after propulsion of the present invention (A) is a removal state diagram of a rigid tube, (b) is a removal state diagram of a distance piece. Partially cutaway sectional view showing a third embodiment of the present invention Partially enlarged sectional view of FIG. The expanded sectional view which shows the other example of the flexible part which concerns on this invention Schematic explanatory diagram shown in the conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Propulsion tube 2 Flexible part 4 Concrete part 5 Steel ring 6 Steel flange 7 Outer peripheral side thrust receiving ring 11 Elastic ring 12 Elastic flange 15 Presser ring 16 Inner peripheral side thrust receiving ring 17 Thrust transmitting ring 30 Rigid pipe 31 Flange 33 Female screw 34 Distance piece 35 Driving jig 36 Female screw 37 Set bolt 38 Drawer bolt 39 Embedded nut 40 Fixing bolt Pa Lead pipe Pb Propulsion pipe Pc Rear pipe

Claims (6)

A steel ring 5 having a concrete-made propulsion tube 1 and an inward steel flange 6 integrated with the outer peripheral surface of the propulsion tube 1 is divided into two in the length direction, and the above-mentioned steel product divided into two is divided. An elastic ring 11 is interposed between the opposing end faces of the flange 6, the elastic flanges 12 at both ends of the elastic ring 11 are applied to the outside of the steel flange 6, and a holding ring 15 is provided outside the elastic flange 12. The elastic flange 12 is clamped and fixed, and the outer circumferential thrust receiving ring 7 is integrated with each steel flange 6 or the inner circumferential thrust receiving ring 16 is integrated with each holding ring 15, and the outer circumferential side or In the flexible propulsion tube formed by abutting the opposed end faces of the inner circumferential thrust receiving rings 7 and 16,
A flexible small-diameter propulsion pipe, wherein a rigid pipe 30 is detachably fitted in the axial direction in the propulsion pipe body 1 across the flexible portion 2.   The flexible small-diameter propulsion pipe according to claim 1, wherein the rigid pipe (30) extends from one end side of the propulsion pipe body (1) to the back side across the flexible portion (2).   The flexible small-diameter propulsion pipe according to claim 2, wherein an outward flange 31 is provided on one end side of the rigid pipe 30.   The flexible small diameter propelling tube according to claim 1, wherein the rigid tube has a length straddling the flexible portion.   5. A clearance S is provided between the propelling tube 1 and the rigid tube 30, and a spacing member 34 is detachably attached to the clearance S from both ends of the rigid tube 30. The flexible small diameter propulsion tube according to any one of the above.   After using the flexible small-diameter propulsion pipe according to any one of claims 1 to 5 as a pipe near the head or a pipe near the tail, and burying the pipe near the head or the tail near the tail by a propulsion method A propulsion method for a flexible small-diameter propelling pipe, wherein the rigid pipe 30 is removed from the flexible small-diameter propelling pipe.

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