JP3863888B2 - Two-stage propulsion method and coupler - Google Patents

Description

  The present invention relates to a two-stage propulsion method and a coupler, and more specifically, a two-stage propulsion method for constructing a buried pipe in a different form in a first half section and a second half section of one propulsion section, and such a two-stage propulsion method. It is used for the coupler that connects the excavator and the buried pipe.

The basic work of a general propulsion method is to propel an excavator and a buried pipe connected to the rear end of the excavator into the ground from the inner wall of the starting shaft excavated in the ground, and The buried pipe will be propelled and buried in the tunnel excavated at the site. If the tip of the buried pipe row connected to the excavator is propelled to the reaching shaft, the propulsion work for one section is completed.
In the normal propulsion method, one type of buried pipe made of steel pipe or fume pipe is constructed over the entire propulsion section.
Apart from this, a construction method called a double pipe propulsion construction method is known. In the double-pipe propulsion method, the first half of the propulsion section close to the starting shaft is buried in a double with a large-diameter outer pipe made of steel pipe and a small-diameter inner pipe made of fume pipe. A pipe will be constructed, and only the inner pipe will be constructed in the latter half of the section near the shaft. The outer pipe is constructed only in the first half section, and the inner pipe is constructed over the entire length of the first half section and the second half section. In the first half section, since the inner pipe and the outer pipe are propelled and buried in a double state, it is called a double pipe propulsion method.

The double-pipe propulsion method is an effective method for preventing excessive fluctuation or collapse of the ground when a structure such as a railway line exists above the ground in the first half section. In addition, in the work of propelling and embedding the inner pipe in the second half section, the resistance from the ground and earth pressure are not applied to the inner pipe that moves in the inner space of the outer pipe in the first half section, so the overall resistance is greatly reduced. However, there is an advantage that the propulsive force is small. A long-distance propulsion method that cannot be sufficiently constructed with one type of buried pipe is possible. The function of protecting the inner pipe from being damaged by pressure, vibration, or impact applied from an upper structure such as a railroad track during and after the construction can be performed.
Patent Document 1 discloses a technique in which a drilling device used in a double pipe propulsion method is provided with a rotary excavator whose outer diameter is variable so that it can be adapted to both the outer pipe and the inner pipe. Has been. In this technology, when a small-diameter inner pipe is propelled and embedded in the latter half section, there is an advantage that an excessive gap is not generated between the outer circumference of the inner pipe and the ground by setting the outer diameter of the excavation small. . It is not necessary to inject a backfill material between the inner pipe and the ground.

In Patent Document 2, in the latter half section of the double pipe propulsion method, a lubricant is injected between the outer periphery of the inner pipe and the ground, thereby smoothly propelling the inner pipe and reducing the added propulsive force. Technology is shown.
Japanese Patent No. 2746866 Japanese Patent No. 2754172

In the conventional double pipe propulsion method, there is a problem that work is troublesome and work efficiency is inferior.
As described above, in the first half of the propulsion section, in the operation of connecting a new buried pipe to the rear end of the buried pipe row, each of the new inner pipe and the outer pipe is doubled and buried. It will be connected to the rear end of the tube row, which will take time and effort. When applying a propulsive force to the buried pipe row with a main jack installed in the starting shaft, it is difficult to apply a propulsive force to the inner and outer double buried pipes. Usually, a propulsive force is applied only to the outer tube, but it is technically difficult and troublesome to ensure that the propelling force is applied only to the outer tube outside the inner tube.
Further, in the first half section, it is difficult to perform the lubricant injection work for reducing the propulsion resistance. In order to reduce the propulsion resistance, a lubricant must be injected between the outer periphery of the outer tube and the ground. However, an inner tube exists inside the outer tube. In order to connect the lubricant supply pipe introduced into the inner space of the inner pipe to the outer pipe through the inner pipe, it is necessary to accurately match the penetration position of the inner pipe with the connection position to the outer pipe. . This is a very time-consuming and technically difficult task. If the lubricant is not supplied in the first half section, the outer tube has a large diameter, so that the contact area with the ground is large and the ground resistance tends to increase. Propulsion cannot be performed smoothly, or excessive thrust is required.

Because of these problems, the double-pipe propulsion method was thought to be a costly propulsion method that required labor and technology for construction, and had poor work efficiency.
An object of the present invention is to eliminate the problems of the conventional double pipe propulsion method, to facilitate the construction, to improve the work efficiency, and to reduce the construction cost.

  The two-stage propulsion method according to the present invention includes a first buried pipe, a second buried pipe, and a second half on the reaching shaft side in the first half section on the starting shaft side among the propulsion sections from the starting shaft to the reaching shaft in the ground. It is a two-stage propulsion method in which only the second buried pipe is constructed in each section, and the second buried pipe has a drilling diameter corresponding to the first buried pipe and an outer diameter smaller than the inner diameter of the first buried pipe. Using the excavator whose excavation diameter is variable to the corresponding excavation diameter, and a coupler that is arranged at the rear end of the excavator and can connect both the first buried pipe and the second buried pipe. The first buried pipe is connected to the coupler of the machine without arranging the second buried pipe, the excavation diameter of the excavator is set to the excavation diameter corresponding to the first buried pipe, and the ground from the start shaft A first half propulsion step (a) in which the first buried pipe is propelled and embedded in the first half section. After the first half propulsion step (a), the connection between the excavator coupler and the first buried pipe is released, and the second buried pipe is disposed in the ground from the starting shaft. A step (b) of passing from the position connected to the coupler of the excavator to the rear end of the row of the first buried pipe, and the excavating diameter of the excavator in the second buried pipe The second buried pipe row set to the corresponding excavation diameter and connected to the coupler of the excavator is propelled into the ground from the front end of the first buried pipe row, and the second half section is reached in the second half section leading to the reaching vertical shaft. And a second half propulsion step (c) of propelling and burying the buried pipe.

[Scope of application of the two-stage propulsion method]
Basically, it can be applied to the construction environment and construction conditions where the normal double pipe propulsion method is applied.
Specifically, use the tunnel space constructed in the ground such as water and sewage pipes, gas pipes, power wiring pipes, information communication line pipes, material transport pipes, and composite pipes of these pipes and wiring. It can be applied to the usage.
[Promotion section]
Basically, it is set in the same manner as the normal propulsion method or double pipe propulsion method.

The propulsion section is a section between the starting shaft and the reaching shaft excavated in the direction perpendicular to the ground. The two-stage propulsion method can be preferably applied when constructing a sewer underground in the first half of this propulsion section with railroad tracks or ground structures.
Even in the case of ordinary ground where there is no railroad track or the like, the two-stage propulsion method is preferably applicable even when a long distance buried pipe is constructed in one propulsion section.
The propulsion route of the propulsion section, that is, the construction route of the buried pipe, is not only when the entire length is a horizontal straight line, but also when there is an inclination with a vertical difference in height or when it is a curve such as an arc, a straight line and a curve are mixed. There is also a case.

At both ends of the propulsion section, a starting shaft and a reaching shaft are constructed. Usually, the starting shaft has a relatively large space because it installs a jack jack or the like, or carries an excavator, a buried pipe or the like. The reaching shaft may be a smaller space than the starting shaft. When removing excavators etc., a space is needed to make it possible. If the excavator is not removed, an existing manhole can be used. The underground part of the building or civil engineering structure can also be used for the starting shaft and the reaching shaft.
[Built pipe]
Basically, the same material and structure as the buried pipe adopted in the normal propulsion method can be applied.

Examples of the material of the buried pipe include a steel pipe, a steel pipe welded with a rib or a reinforcing frame, a concrete pipe, a reinforced concrete pipe, a fume pipe, an FRP pipe, a synthetic resin pipe, and a ceramic pipe. A composite tube in which a plurality of material layers are laminated can also be used. From these pipe materials, pipe materials suitable for the required performance of the first buried pipe and the second buried pipe may be combined.
The diameter and length of the buried pipe also differ depending on the difference in materials and construction conditions. Usually, the aperture defined by the inner diameter can be set in the range of 800 to 3000 mm. The length can be set in the range of 800 to 5000 m.
The first buried pipe uses a pipe material having a relatively large diameter and excellent proof stress. For example, a steel pipe is used. The second buried pipe has a relatively small diameter, and a pipe material suitable for a use application such as a sewer is used. For example, in the case of sewerage, a fume pipe is used. The outer diameter of the second buried pipe is made smaller than the inner diameter of the first buried pipe. The more the gap between the inner periphery of the first embedded tube and the outer periphery of the second embedded tube is, the easier the second embedded tube passes through the inside of the first embedded tube. However, it is necessary to widen the variable range of the excavating diameter of the excavator. When the second buried pipe is propelled to the ground, there is a possibility that the protruding amount of the coupler increases and the ground resistance increases. Usually, the radial gap between the inner circumference of the first buried pipe and the outer circumference of the second buried pipe can be set to 15 to 200 mm on one side.

A connecting structure such as a fitting shape or an engaging shape for connecting the embedded tubes back and forth can be provided at the end of the embedded tube. It is also possible to provide a sealing structure that enhances the sealing performance to prevent the intrusion of earth and sand and groundwater from the connection point.
[Digging machine]
Basically, the same material and structure as the excavator used in the normal propulsion method can be applied.
Among the excavators, a mechanism that forms a tunnel for excavating the ground and propelling the buried pipe can be provided with a rotary excavator that rotates with a excavation bit and an excavation blade on the front surface. A consolidation cone can be provided to consolidate the ground to the surroundings and expand the tunnel. A muddy water supply device that ejects muddy water to the ground and discharges the mud with the muddy water can be provided.

The excavating diameter of the excavator with such various excavating structures needs to be variable. For example, the technology disclosed in Japanese Patent No. 2746866 can be applied to the structure of the excavator having a variable excavation diameter. Specifically, a part or the whole of the excavation bit and the excavation blade only needs to be able to advance and retreat in the radial direction of the excavator. In order to advance and retract the excavation bit, various operation mechanisms such as a hydraulic mechanism, an electromagnetic actuator, a link mechanism, a cam mechanism, and a gear mechanism can be employed.
If the excavating diameter of the excavator is continuously variable within a certain range, it is easy to cope with a buried pipe having an arbitrary outer diameter that varies depending on the construction conditions. It is sufficient that the excavation diameter is variable at least in two stages, that is, the excavation diameter corresponding to the first buried pipe used for the construction and the excavation diameter corresponding to the second buried pipe.

A connecting structure for connecting the buried pipe is usually provided at the rear end of the excavator. Specifically, for example, the peripheral wall material is slightly protruded at the rear end of the excavation machine, and the buried pipe is inserted therein.
A connector can be connected using this connection structure for buried pipe connection. Of course, a shape and a structure necessary for connection with the coupler can be added.
[Connector]
It arrange | positions at the rear end of an excavation machine, and can connect any of a 1st buried pipe and a 2nd buried pipe.
If the first buried pipe and the second buried pipe having different diameters can be connected simultaneously or separately to the same excavator, a connection structure in a normal civil engineering device or mechanical device can be employed. In a normal excavator, a structure for connecting buried pipes, a structure for connecting buried pipes, and the like can be used. Of course, in a normal double pipe propulsion method, a structure for connecting the inner pipe and the outer pipe to the excavator can also be used.

It is preferable that the coupler does not take a place in the front-rear direction or the inner peripheral side as much as possible and does not travel on the outer peripheral side. It is desirable to easily connect and disconnect and to have excellent sealing performance at the connection point.
The following structure can be adopted as the structure of the coupler.
The whole has a substantially cylindrical shape, and is connected to the front end connecting portion that is fitted and connected to the rear end of the excavator, and the front end of the first buried pipe, and is connected to the first buried pipe on the outside from the inside of the coupler. A rear end connecting portion that is detachably fixed, a connecting step portion that is disposed on an inner peripheral side of the rear end connecting portion, and is connected by inserting a tip of the second embedded pipe, and the rear end connecting portion. And a tapered peripheral surface connecting the peripheral surface of the tip connecting portion.

Since the rear end of the excavator usually has an insertion structure for connecting the buried pipe, a complicated structure is added if the front end connecting portion of the coupler can be inserted into the rear end of the excavator. There is no need. A sealing mechanism such as a sealing ring can be provided on the outer peripheral surface facing the excavator in the tip connecting portion. An engagement mechanism, a screwing mechanism, and a fastening mechanism for fixing to the excavator can also be provided. A centering mechanism that aligns the shaft center of the excavator and the shaft center of the coupler can also be provided.
Unlike the connection structure of the buried pipe provided at the rear end of the normal excavator, the rear end connection part is fitted and connected to the front end of the first buried pipe. The rear end connecting portion is provided with a fixing mechanism that is detachably fixed to the first buried pipe on the outer side from the inner side of the coupler. As a result, the connection between the first buried pipe and the coupler can be strengthened. If the fixing mechanism is operated from the inside of the coupler, the operation of releasing the coupling between the coupler and the first buried pipe in the ground is easy. As the fixing mechanism, a bolt fastening, an engagement / disengagement fitting, or the like can be adopted. By using an urging force such as a spring, the fixing or releasing operation can be easily performed. The connection can be released remotely by using electromagnetic force or hydraulic pressure.

Basically, a connection structure of buried pipes in a normal excavator can be used as the connection step. It is desirable to provide it on the inner peripheral side that does not interfere with the structure and operation of the rear end connecting portion. Since the connection of the second buried pipe to the connecting step portion is performed inside the first buried pipe in a state where the coupler is propelled in the ground, the connection of the second buried pipe is performed in such an environment. It is desirable to provide it in a place or structure that is easy to perform.
The tapered peripheral surface connects the outer peripheral surface of the rear end connecting portion having a different outer diameter and the outer peripheral surface of the front end connecting portion. When the coupler is propelled on the ground, the ground smoothly contacts the outer peripheral surface of the excavator or the outer peripheral surface of the tip connecting portion through the tapered peripheral surface to the rear end connecting portion and the member behind it. Since the transition, the resistance during propulsion can be reduced. The taper peripheral surface can also exert the function of pressing the ground to the outer peripheral side for consolidation. The smaller the angle of inclination of the tapered peripheral surface with respect to the horizontal line, the lower the resistance from the ground. However, in order to shorten the length of the coupler, it is better to increase the inclination angle of the tapered peripheral surface.

[First half propulsion process (a)]
Basically, the first buried pipe is used as the buried pipe, and the same work as a normal propulsion method that is not a double pipe propulsion method is performed.
The first buried pipe is connected to the coupler attached to the excavator without arranging the second buried pipe. The excavation diameter of the excavator is set to the excavation diameter corresponding to the first buried pipe. From the starting shaft, the excavator, the coupler, and the first buried pipe are propelled into the ground. The first buried pipe is propelled and buried to a predetermined distance that becomes the end point of the first half section.
The front end of the coupler can be fitted and connected to the rear end of the excavator, and the rear end of the coupler can be fitted and connected to the front end of the first buried pipe. If it does in this way, the outer peripheral shape of a connector does not protrude on the outer periphery of an excavation machine, or the outer periphery of a 1st buried pipe in the connection part before and behind a connector. The coupler does not generate a large resistance from the ground. A structure for connecting a normal buried pipe provided at the rear end of the excavator can be used as it is. There is no need to change the structure of the excavator. The first buried pipe and the second buried pipe can be separated and connected to the inner and outer circumferences at the rear end of the coupler. Both of the buried pipes can be easily connected.

When propulsion embedding of the first buried pipe, the lubricant can be supplied between the first buried pipe and the ground from the lubricant supply pipe introduced into the first buried pipe. The first buried pipe can be provided with a lubricant supply port for discharging the lubricant to the outer peripheral surface. As the sliding material supply pipe, the lubricating material supply port, and the branch pipe structure for connecting the lubricating material supply tube to the lubricating material supply port, a structure common to the lubricating material supply structure in the normal propulsion method can be adopted. The method for supplying the lubricant can be performed in the same manner as the normal propulsion method.
[Second Embedded Pipe Arrangement Step (b)]
After the first half propulsion step (a), the connection between the excavator coupler and the first buried pipe is released. A 2nd buried pipe is made to pass through the inside of the 1st buried pipe arrange | positioned in the ground from a starting shaft, and is arrange | positioned from the position connected with the coupler of an excavation machine to the row | line | column rear end of a 1st buried pipe.

The connection between the coupler and the first buried pipe is released from the internal space of the first buried pipe in the ground. It can also be made possible to release the connection from the starting shaft or from the ground.
The second buried pipe is carried into the starting shaft from the ground, and transferred from the rear end of the first buried pipe opened in the starting shaft to the inside of the first buried pipe. The second buried pipes arranged at the front and rear are connected by a normal buried pipe connecting means. At the head of the second buried pipe row, the tip of the second buried pipe is connected to the rear end of the coupler. The second buried pipe is connected to the coupler on the center side of the inner peripheral surface of the first buried pipe connected to the coupler.

The second buried pipe can be fitted and connected to the rear end of the coupler. If it does in this way, a 2nd buried pipe can be connected with a coupler by the same structure and operation | work which connects a buried pipe with the rear end of an excavation machine by a normal propulsion method. There is no need to add a special connection structure to the tip of the second buried pipe.
[Second half promotion process (c)]
The excavation diameter of the excavator is set to the excavation diameter corresponding to the second buried pipe. The row of second buried pipes connected to the coupler of the excavator is propelled from the front end of the first buried pipe into the ground. The second buried pipe is propelled and buried in the latter half of the section leading to the shaft. A second buried pipe is also arranged inside the first buried pipe.

Basically, in the normal double-pipe propulsion method, the same technology as the propulsion work in the latter half section where the inner pipe is propelled and buried is applied.
In this step, the lubricant can be supplied between the second buried pipe and the ground. Specifically, a technique common to the lubricant supply in the first half propulsion process described above can be applied. However, it is not necessary to supply the lubricant to the first buried pipe row that is not propelled.
When this process is completed, the second buried pipe is constructed in all propulsion sections from the starting shaft to the reaching shaft. The first buried pipe is constructed only in the first half section from the starting shaft to the middle of the propulsion section. In the first half section, the second buried pipe row is arranged inside the first buried pipe row.

[Other processes]
After the construction of the first buried pipe and the second buried pipe is completed, a post-treatment process similar to a normal propulsion method or a double pipe propulsion method can be performed.
For example, the sealing process can be performed on the connection portion between the second embedded pipes. A coating layer can be formed by coating on the inner surface of the second buried pipe. It is also possible to carry out in-place installation with a sheet or the like. The second buried pipe and the first buried pipe can be filled with a mortar or attached with an opening frame at a portion opened to the starting shaft and the reaching shaft. Illumination can be installed inside the second buried pipe, and power wiring and communication wiring can be laid.

In the two-stage propulsion method according to the present invention, in the first half propulsion process, only the first buried pipe is connected to the rear end of the excavator and the coupler in the first half section of the propulsion section. The same work as the propulsion method using one type of buried pipe can be performed. The work of connecting a new buried pipe to the rear end of the buried pipe row, the addition of propulsive force with a push jack, the supply of lubricant, etc. can be done easily and efficiently, just like the ordinary propulsion method. .
Before constructing the second half section, the operation of arranging the second buried pipe from the position connected to the rear end of the coupler through the inside of the first buried pipe row to the rear end of the first buried pipe row is Since the work is performed inside the first buried pipe row that does not receive any resistance, it can be efficiently performed without any problem.

After that, as the latter half of the propulsion process, the work of pushing and burying the second buried pipe in the latter half section is smooth and efficient with the resistance from the ground greatly reduced, as in the conventional double pipe propulsion method. Yes.
As a result, the disadvantages of the double pipe propulsion method can be eliminated without impairing the advantages of the conventional double pipe propulsion method, and the work efficiency and work quality can be significantly improved economically.

1-7 has typically shown embodiment in the case of constructing a sewer etc. under the railroad track.
[Overview of the propulsion method]
As shown in FIG. 7, on both sides of the railway track R, the starting shaft H1 and the reaching shaft H2 are excavated on the ground E, and the buried pipe 10 is embedded in the ground E in the propulsion section from the starting shaft H1 to the reaching shaft H2. 20 is constructed.
Among the propulsion sections, the first half section close to the starting shaft H1 includes a row of first buried pipes 10 made of steel pipes and a row of second buried pipes 20 made of fume pipes arranged inside the first buried pipe 10. Is constructed twice. The outer diameter of the second embedded pipe 20 is smaller than the inner diameter of the first embedded pipe 10. In the latter half section close to the reaching shaft H2, only the row of the second buried pipes 20 is constructed. The inside of the second row of buried pipes 20 over the entire length of the propulsion section is used for sewerage and the like.

In the figure, the length of the latter half section in which only the second buried pipe 20 is constructed is omitted, and actually the latter half section is considerably longer than the first half section.
In the first half section crossing the railroad track R, the first buried pipe 10 having excellent strength covers the outer periphery of the second buried pipe 20, so that problems such as ground fluctuation and collapse occur below the railway line R. It can be effectively prevented.
[Construction of the first half section]
As shown in FIG. 1, a row of first buried pipes 10 connected to the rear end of the excavating machine 30 and the excavating machine 30 via a connector 40 from the inner wall of the starting shaft H1 toward the inside of the ground E. Burying, propulsion.

Basically, the same equipment, equipment, and working method as the propulsion method using one ordinary type of buried pipe are employed.
<Digging machine>
The excavator 30 basically has the same structure as an ordinary excavator for a propulsion method.
The outer diameter of the excavator 30 that is generally cylindrical as a whole is set according to the outer diameter of the second buried pipe 20. The outer diameter is smaller than the outer diameter of the first buried pipe 10. The rotary excavator 32 provided at the tip of the excavator 30 includes a movable excavation bit 34 in addition to a normal excavation bit and an excavation blade. The movable excavation bits 34 are arranged at a plurality of locations along the outer peripheral edge of the rotary excavator 32 and advance and retract in the radial direction. Although not shown, the movable excavation bit 34 is advanced and retracted by a hydraulic actuator built in the rotary excavator 32. FIG. 1 shows a state where the movable excavation bit 34 is moved to the outside of the outer diameter of the excavator 30. The excavation diameter determined by the outer diameter of the movable excavation bit 34 corresponds to the outer diameter of the first buried pipe 10.

Although not shown, the excavator 30 measures the position of the excavator 30 by a motor and a speed reducer that rotate the rotary excavator 32, a soil removal mechanism that discharges the earth and sand excavated by the rotary excavator 32, and the excavator 30. The same mechanism and device as those of the ordinary excavator 30 are mounted, such as a surveying device to be used and a turning jack for changing the excavation direction of the excavator 30.
<Connector>
As shown in detail in FIG. 2, a coupler 40 is fitted and connected to the cylindrical rear end of the excavator 30. The entire connector 40 is formed of a steel material and has a substantially cylindrical shape.
A distal end coupling portion 46 is provided on the distal end side of the coupler 40. The outer diameter of the tip connecting portion 46 corresponds to the inner diameter of the cylindrical rear end of the excavator 30. On the outer peripheral surface of the distal end connecting portion 46, annular sealing rings 47 are mounted at two front and rear positions. The outer peripheral end of the sealing ring 47 is in contact with the inner surface of the rear end of the excavating machine 30 to ensure the sealing performance between the two.

A rear end connecting portion 42 is provided on the rear end side of the connector 40. The outer diameter of the rear end connecting portion 42 is matched to the inner diameter of the connecting ring portion 12 integrally welded to the tip of the first first embedded tube 10 in the row of the first embedded tubes 10. By inserting the rear end connecting portion 42 into the connecting ring portion 12 of the first buried pipe 10, the outer peripheral surface of the rear end connecting portion 12 and the inner peripheral surface of the connecting ring portion 12 are brought into contact with each other and are connected to each other. The
On the inner peripheral side of the rear end connecting portion 42, a fitting step portion 44 corresponding to the tip shape of the second embedded pipe 20 is provided. The second embedded pipe 20 can be fitted and connected to the fitting step 44.
Screw holes 43 and 43 penetrating the coupler 40 are provided at two positions on the rear end side on the rear end side of the fitting step portion 44. The screw holes 43 are equally arranged at predetermined angles in the circumferential direction of the coupler 40. Bolts 70 are screwed into the screw holes 43. The tip of the bolt 70 is screwed into the screw hole 14 provided in the connection ring portion 12 of the first buried pipe 10. As a result, the coupler 40 and the first buried pipe 10 are firmly connected and fixed. The screw hole 14 of the connecting ring portion 12 is closed by a closing plate 15 made of a thin steel plate welded to the outer peripheral surface of the connecting ring portion 12. The blocking plate 15 prevents earth and sand and groundwater from entering through the screw holes 14 even after the bolts 70 are removed.

A bolt 72 is screwed from the inner surface side to the outer surface side at a predetermined angle in the circumferential direction also on the front side of the fitting step portion 44 in the coupler 40. The tip of the bolt 72 is screwed into the screw hole 16 provided in the connecting ring portion 12. The screw hole 16 is opened and exposed on the outer peripheral surface of the connecting ring portion 12.
An O-ring 45 is mounted between the outer peripheral surface of the connector 40 and the inner peripheral surface of the connecting ring portion 12 on the front side of the mounting position of the bolt 72. The O-ring 45 is attached to a circumferential groove provided on the coupler 40 side and is pressed against the inner surface of the coupling ring portion 12. This prevents earth and sand and groundwater from entering from the front end side of the connecting ring portion 12.

On the outer peripheral surface of the coupler 40, the front side of the O-ring 45 is a tapered peripheral surface 49 connected to the outer peripheral surface of the tip connecting portion 42. The tapered peripheral surface 49 has a function of reducing ground resistance when the second embedded pipe 20 is propulsion embedded.
The row of the first buried pipes 10 is connected to the excavator 30 by the coupler 40 having the structure described above.
<Supplying lubricant>
As shown in FIG. 1, a lubricant supply pipe 60 is introduced from the ground to the inside of the first buried pipe 10 through the inside of the starting shaft H1. The lubricant supply pipe 60 is branched at a plurality of locations on the front and rear sides, and each branched tip is connected to a lubricant supply port 62 installed on the tube wall of the first buried pipe 10. Since the second embedded pipe 20 does not exist inside the first embedded pipe 10, the piping attachment from the lubricant supply pipe 60 to the lubricant supply port 62 can be easily performed.

The lubricant supplied to the gap with the ground E from the lubricant supply port 62 reduces the frictional resistance applied from the ground E when the first buried pipe 10 is propelled. Propulsion is performed smoothly, the propulsive force to be added can be reduced, and the propulsion time can be shortened.
<Promotion work>
As shown in FIG. 1, a main jack 50 is installed on the starting shaft H1. The front end of the operating shaft 52 of the main push jack 50 abuts against the rear end of the first buried pipe 10 via the abutment plate 54.
In this state, while rotating the rotary excavator 30 of the excavator 30 and excavating the ground E, the operating shaft 52 of the main push jack 50 is advanced forward, and the row of the excavator 30 and the first buried pipe 10 is moved. Push forward.

When the propulsion work for one first buried pipe 10 is completed, a new first buried pipe 10 is connected to the rear end of the first buried pipe 10 in the starting shaft H1, and the above-described propulsion is performed again. Do work. In FIG. 1, the depth of the starting shaft H1 is displayed narrower than the actual depth because of the drawing space. Actually, a sufficient margin is provided between the main push jack 50 and the rear end of the first buried pipe 10 for inserting and arranging a new first buried pipe 10.
The propulsion work of the first buried pipe 10 described above is basically not significantly different from the normal propulsion method.
When the first buried pipe 10 is propelled and buried in the entire lower region of the railway track R, the construction of the front section is completed.

[Arrangement of second buried pipe]
As shown in FIGS. 3 and 4, the second buried pipe 20 is arranged.
Specifically, after the propulsion work of the first buried pipe 10 is finished, the operation shaft 52 of the main pushing jack 50 is moved backward. The contact plate 54 is removed. The lubricant supply pipe 60 inside the row of the first buried pipes 10 is removed, and the lubricant supply port 62 is closed.
<Disconnect>
As shown in detail in FIG. 4, the bolt 70 is removed inside the coupler 40. Since the outer peripheral surface of the screw hole 43 of the coupler 40 and the screw hole 14 of the coupling ring portion 12 is closed by the closing plate 15, there is no concern that earth and sand or groundwater will flow in even without the bolt 70. .

The other bolt 72 is loosened so that the tip of the bolt 72 is arranged on the inner peripheral side of the screw hole 16 of the connecting ring portion 12. As a result, the connection between the connecting ring portion 12 and the connector 40 by the bolt 72 is released.
The bolt 72 is in a state where the head protrudes from the inner periphery of the coupler 40. In this state, even if groundwater or the like tries to enter from the screw hole 16 of the connecting ring portion 12, entry into the inner side of the bolt 72 can be reliably prevented. However, since the bolt 72 is screwed in an unstable state, the half rings 74 and 74 are attached to fix the position of the bolt 72.
The half rings 74 and 74 are made of steel or the like and have a structure in which a cylinder is divided into two. If the split rings 74, 74 are attached between the bolt 72 and the inner peripheral surface of the coupler 40, and the bolt 72 is tightened and fixed a little, the bolt 72 can be removed even if vibration or impact is applied. It is prevented that the connector is pulled out or protrudes to the outer peripheral surface of the coupler 40.

Although FIG. 4 shows a state where the second embedded pipe 20 is present, the actual connection release operation is performed in a state where the second embedded pipe 20 does not exist, and thus the inside of the wide first embedded pipe 10 You can work with ease with ease.
<Insertion of second buried pipe>
The second buried pipe 20 is carried from the ground to the starting shaft H 1 and inserted into the first buried pipe 10. The second embedded pipe 20 is arranged from the beginning to the end of the row of the first embedded pipe 10. The second embedded pipe 20 is arranged from the rearmost end of the row of the first embedded pipes 10 to the state where the rearmost end of the second embedded pipe 20 protrudes. The front and rear second buried pipes 20 are connected to each other by a normal connecting means between the buried pipes before entering the first buried pipe 10 inside the start shaft H1.

As shown in detail in FIG. 4, the tip of the second embedded pipe 20 is connected by being fitted into the fitting step 44 of the coupler 40. At this time, the outer peripheral surface of the second embedded tube 20 contacts the sealing brush 18 attached to the inner peripheral surface of the first embedded tube 10.
As shown in detail in FIG. 2, the sealing brush 18 is attached to the front and rear two locations on the inner peripheral surface of the first first embedded tube 10. The sealing brush 18 has a plurality of elastic sealing pieces 19 protruding obliquely forward toward the center at the tip of the annular main body portion. The elastic sealing piece 19 is made of a rubber plate or the like. The sealing brush 18 and the elastic sealing piece 19 are disposed in close contact over the entire inner peripheral surface of the first embedded pipe 10.

As shown in FIG. 4, when the second embedded tube 20 advances to the position of the sealing brush 18 of the first embedded tube 10, the elastic sealing piece 19 of the sealing brush 18 is surrounded by the outer peripheral surface of the second embedded tube 20. Push away to the side. Due to the repulsive force of the elastic sealing piece 19, the elastic sealing pieces 19 on the entire circumference and between the elastic sealing piece 19 and the outer peripheral surface of the second embedded pipe 20 are well sealed.
Since the insertion operation of the second embedded pipe 20 is performed inside the row of the first embedded pipes 10 isolated from the ground E, no great resistance acts on the movement of the second embedded pipe 20. Even if a large force is not applied by the main push jack 50, the insertion work can be performed only by pushing it manually or by pulling it with a simple winch device. Of course, it is also possible to sequentially push the second embedded pipe 20 forward using the main pushing jack 50. In this case, the pushing force applied by the main pushing jack 50 may be much smaller than the propulsion work.

[Second half section construction]
Basically, the same work procedure as the propulsion work of the inner pipe, that is, the second buried pipe 20 in the conventional double pipe propulsion method can be applied.
As shown in FIG. 5, the movable excavation bit 34 of the excavator 30 is withdrawn toward the center side. The excavation diameter corresponds to the outer diameter of the excavator 30 and the second buried pipe 20.
The distal end of the operating shaft 52 of the main pushing jack 50 is pressed against the rear end of the second buried pipe 20 via the contact plate 54. The lubricant supply pipe 60 introduced into the starting shaft H1 is laid in the row internal space of the second buried pipes 20. The lubricant supply pipe 60 is connected to the lubricant supply port 62 provided on the peripheral wall of the second embedded pipe 20 in front of the row of the first embedded pipes 10.

While excavating the ground E with the rotary excavator 32 of the excavator 30, the row of the excavator 30 and the second buried pipe 20 is propelled by the propulsive force applied by the main push jack 50. A lubricant is supplied between the outer peripheral surface of the second buried pipe 20 and the ground E to reduce the resistance from the ground E.
After one second buried pipe 20 is propelled, a new second buried pipe 20 is sequentially connected to the rear end of the row of the second buried pipe 20 that has already been promoted in the starting shaft H1.
As shown in detail in FIG. 6, when the second embedded tube 20 is propelled through the center of the stationary first embedded tube 10, the second embedded tube 20 is provided on the inner peripheral surface of the first embedded tube 10. Since the sliding is carried out while abutting in the dragging direction of the elastic sealing piece 19 of the brush 18, the second embedded pipe 20 is propelled while always maintaining a good sealing state.

The connecting pipe 40 comes out of the connecting ring part 12 of the first buried pipe 10. Even if earth or sand or groundwater enters from the end of the first buried pipe 10 or the screw holes 16, 14, the sealing function by the sealing brush 18 described above causes a position deeper than the position of the sealing brush 18. , Earth and sand and groundwater cannot easily penetrate. Since the groundwater pressure from the ground E side acts so as to press the elastic sealing piece 19 against the outer peripheral surface of the second buried pipe 20, the sealing function is further increased. Since the sealing brushes 18 are provided at two positions in the front and rear, it is practically impossible to pass both sealing brushes 18.
Since the bolt 72 remains screwed on the tip side of the coupler 40, earth and sand and groundwater do not enter the inner peripheral side of the coupler 40 from the location of the bolt 72. The O-ring 45 no longer functions as a seal with the first embedded pipe 10, but does not cause a major problem even if it remains attached. The tapered peripheral surface 49 on the distal end side of the coupler 40 can smoothly push away the tunnel of the ground E excavated corresponding to the excavating diameter of the excavator 30 to the outer peripheral side with the tapered peripheral surface 49. Even if there is a portion having a slightly larger outer diameter than the excavated diameter, there will be no significant hindrance to the propulsion work. There is also an advantage that the resistance and earth pressure from the surrounding ground E applied to the subsequent second buried pipe 20 can be reduced by expanding the tunnel of the ground E with the tapered peripheral surface of the coupler 40.

In the range of the second buried pipes 20, the resistance from the ground E is not received at all in the range arranged inside the first buried pipe 10, so even if the second buried pipe 20 becomes long, the ground E The resistance from is applied only in the latter half section not covered with the first buried pipe 10. The second buried pipe 20 is smoothly promoted, and the propulsive force applied by the main push jack 50 can be small. It is also easy to propel the second embedded pipe 20 over a long distance.
[End of propulsion method]
As shown in FIG. 7, when the second buried pipe 20 is arranged from the starting shaft H1 to the reaching shaft H2, the propulsion work is completed. Subsequent operations can be performed in the same manner as in the normal propulsion method.

The excavator 30 and the coupler 40 may be removed from the top of the second buried pipe 20 and removed from the reaching shaft H to the ground. In the starting shaft H1, the equipment for propulsion work such as the main jack 50 is removed.
Inside the row of the second buried pipes 20, an operation of removing the lubricant supply pipe 60 and closing the lubricant supply port 62 is performed. A coating layer can be applied to the inner surface of the second buried pipe 20. It is also possible to perform a process of placing mortar between the inner walls of the starting shaft H1 and the reaching shaft H2 and the ends of the first buried pipe 10 and the second buried pipe 20 to close them.
The underground underground pipe structure completed in this way can be used for sewerage and the like. In the lower region of the railroad track R, the first buried pipe 10 made of a steel pipe having excellent proof stress surrounds and protects the outer circumference of the second buried pipe 20 made of a fume pipe. Even if the pressure applied from the structure of the railroad track R or the pressure of the ground fluctuating due to passage of the train acts, the second buried pipe 20 can be prevented from being damaged or causing water leakage.

  The two-stage propulsion method according to the present invention can be effectively applied to, for example, construction of a sewer under the railroad track. The construction of the buried pipe can be performed easily and efficiently without adversely affecting the railway track and without being adversely affected by the railway track.

Sectional drawing which shows the construction state of the first half section used as embodiment of this invention Detailed sectional view of the main part in the previous figure Sectional drawing which shows the construction state of arrangement | positioning work of 2nd buried pipe Detailed sectional view of the main part in the previous figure Sectional view showing the construction status of the second half section Detailed sectional view of the main part in the previous figure Sectional view showing the end state of the propulsion method

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st buried pipe 12 Connection ring part 18 Sealing brush 20 2nd buried pipe 30 Excavator 32 Rotary excavation machine 34 Movable excavation bit 40 Connector 42 Rear end connection part 44 Fitting step part 46 Front end connection part 49 Tapered peripheral surface 50 Movable jack 60 Lubricant supply pipe 62 Lubricant supply port E Ground R Railway track

Claims (4)

Among the propulsion sections from the starting shaft to the reaching shaft in the ground, the first and second buried pipes are provided in the first half section on the starting shaft side, and only the second buried pipe is provided in the second half section on the reaching shaft side. Each is a two-stage propulsion method,
An excavator having a variable excavation diameter between a drilling diameter corresponding to the first buried pipe and a drilling diameter corresponding to the second buried pipe having an outer diameter smaller than the inner diameter of the first buried pipe; Using a coupler arranged at the end and capable of connecting both the first buried pipe and the second buried pipe,
The first buried pipe is connected to the coupler of the excavator without arranging the second buried pipe, the excavating diameter of the excavator is set to the excavating diameter corresponding to the first buried pipe, and from the starting shaft A first half propulsion step (a) in which the first buried pipe is propelled and buried in the first half section by being propelled into the ground;
After the first half propulsion step (a), the connection between the excavator coupler and the first buried pipe is released, and the second buried pipe is disposed in the ground from the starting shaft. A step (b) of passing through the interior of the first excavator from the position connected to the coupler of the excavator to the rear end of the row of the first buried pipes;
The excavation diameter of the excavator is set to an excavation diameter corresponding to the second buried pipe, and the second buried pipe row connected to the coupler of the excavator is moved from the front end of the first buried pipe into the ground. A two-stage propulsion method including a second half propulsion step (c) in which a second buried pipe is propelled and buried in the second half section leading to the reaching shaft. In the first half propulsion step (a), the front end of the coupler is inserted and connected to the rear end of the excavator, and the rear end of the coupler is inserted and connected to the front end of the first buried pipe (a -1),
The two-stage propulsion method according to claim 1, wherein the latter half propulsion step (b) includes a step (b-1) in which the second buried pipe is inserted and connected to a rear end of the coupler. The first half propulsion step (a) includes a step (a-2) of supplying a lubricant between the first buried pipe and the ground from the lubricant supply pipe introduced into the first buried pipe,
In the latter half propulsion step (c), in front of the construction site of the first buried pipe, from the lubricant supply pipe introduced into the second buried pipe, between the second buried pipe and the ground. The two-stage propulsion method according to claim 1 or 2, comprising a step (c-1) of supplying a lubricant. A coupler used in the two-stage propulsion method according to claim 2,
The whole is roughly cylindrical,
A tip connecting portion that is fitted and connected to the rear end of the excavator;
A rear end coupling portion that is fitted into the front end of the first buried pipe and is detachably fixed from the inside of the coupler to the outer first buried pipe;
A connecting step portion disposed on the inner peripheral side of the rear end connecting portion and connected by being fitted with a tip of the second embedded pipe;
A coupler for a two-stage propulsion method, comprising a tapered circumferential surface connecting the outer circumferential surface of the rear end coupling portion and the outer circumferential surface of the tip coupling portion.

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