JP3139859B2 - Air bag for supporting soft ducts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft duct which is attached to a moat to support the soft duct from the inner peripheral surface when the soft duct is propelled when propelling and embedding a soft duct in a tunnel excavated by a moat. The present invention relates to an air bag for supporting a duct.

[0002]

2. Description of the Related Art A soft duct formed by a synthetic resin or the like in a bare tunnel with the advance of the trench by excavating the ground with a moat such as an auger screw and forming a tunnel. Is disclosed in Japanese Utility Model Laid-Open No. 1-180591, Japanese Utility Model Laid-Open No. 26696/1990, and the like.

[0003] This is to provide an air bag on the outer periphery of a steel pipe which is a casing of an auger screw which is a moat machine,
A fluid is press-fitted into the air bag, and the soft duct externally fitted to the steel pipe is supported from the inside by inflation, thereby propelling the soft duct.

[0004]

However, since frictional resistance acts between the outer peripheral surface of the soft duct and the unexcavated tunnel, the contact surface of the airbag with the soft duct is opposite to the propulsion direction. A large load acts in the direction. As a result, the contact surface between the airbag and the soft duct slips or the airbag is deformed, so that the propulsion amount of the soft duct is smaller than the propulsion amount of the propulsion device. The propulsion force of the propulsion unit could not be increased as much as necessary because the base portion came into contact with the rear end surface of the soft duct and the axial force of the propulsion device was directly applied to the rear end surface.

In view of the above, the present invention provides an air bag for supporting a soft duct capable of strongly supporting the soft duct from the inside thereof and applying a large propulsive force of an auger screw casing to the soft duct. The purpose is to do.

[0006]

As a result of repeated studies by the present inventors, in order to support a flexible duct with a large supporting force and suppress deformation during propulsion, a cord layer is provided inside a flexible duct supporting airbag. Is effective, and it has been found that the code angle of the code layer has an optimum value.

According to the present invention, the air bag is provided by expanding a cylindrical air bag having an annular air chamber provided on the outer periphery of a casing of an auger screw for transmitting thrust of a main pushing jack to a tip blade and having an expandable and contractible inside. A soft duct supporting airbag used in a method of supporting and embedding the soft duct loosely fitted in the soft duct from the inside, wherein the soft duct supporting airbag is 0 ° to the propulsion direction. It is characterized by having a code layer made of a code inclined at 45 °.

[0008]

When air is supplied to the air duct for supporting the flexible duct of the present invention, the air chamber expands, and the outer peripheral surface is pressed against and adheres to the inner peripheral surface of the flexible duct. It is supported via a supporting airbag. When thrust is applied to the casing by the main push jack, the soft duct is supported by the soft duct supporting airbag and propelled in the tunnel excavated by the tip cutting edge.

[0009] The air bag for supporting the flexible duct of the present invention is provided with a cord layer, so that high-pressure air can be filled therein, and the cord direction of the cord layer is 0 ° with respect to the propulsion direction. Since the air chamber is inclined at an angle of about 45 °, radial expansion of the air chamber is allowed, and deformation of the outer shape in the propulsion direction can be suppressed. Therefore, the soft duct supporting airbag can strongly support the soft duct from the inside, and can reliably apply a large propulsive force of the casing to the soft duct.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows a moat driving machine 10 to which the present invention is applied.
Is schematically shown. As shown in FIG. 2, the excavator 10 is provided with a cylindrical casing 12, and a plurality of casings 12 are joined according to the length of a tunnel to be excavated. A cutter 14 for digging in the ground is provided on the casing 12 on the tip side in the digging direction (direction of arrow A).
Is attached. Inside the casing 12, there is provided a screw 16 for transporting excavated soil excavated by the cutter 14 to a shaft (not shown) on the opposite side of the cutter 14.

A soft duct 17 for supporting the inner surface of the excavated tunnel is provided outside the casing 12. In this embodiment, the inner diameter D1 of the soft duct 17 is φ600 mm (see FIG. 1).

The casing 12 of the present embodiment has a double structure having an outer pipe 12A and an inner pipe 12B disposed inside the outer pipe 12A.
The screw 16 described above is disposed inside B.
In this embodiment, the outer diameter D2 of the outer pipe 12A is φ
532 mm (see FIG. 1). Also, the inner pipe 12B
Is fixed to the outer pipe 12A via a spacer (not shown).

A cylindrical air bag 22 is attached to the outer periphery of an outer pipe 12A of a predetermined casing 12 of the plurality of connected casings 12 in close contact therewith.

As shown in FIG. 2, the air bag 22
A ring-shaped first inner surface rubber 24 is provided at the center. First
The inner rubber 24 has a rectangular shape whose cross section along the axis is long in the axial direction, and a release sheet 26 is continuously embedded in the center in the thickness direction along the circumferential direction. This release sheet 2
Numeral 6 is formed of a material to which rubber does not adhere. In this embodiment, a sheet made of reinforced polyethylene is used. Both ends in the width direction of the release sheet 26 are the first inner rubber 2
4 are located inward in the width direction from both ends in the width direction. As shown in FIG. 3, the release sheet 26 is for forming an air chamber 25 in the first inner rubber 24, and when air is supplied between the release sheet 26 and the first inner rubber 24, The separation sheet 26 and the first inner rubber 24 are separated from each other, and the volume of the air chamber 25 in the first inner rubber 24 increases. In the present embodiment, the thickness of the first inner rubber 24 is about 2 mm.

As shown in FIG. 1, the first inner rubber 24
Is entirely covered with the second inner rubber 28.
The second inner rubber 28 is vulcanized and bonded to the first inner rubber 24, but a sheet-like peeling member 30 having a U-shaped cross section is provided only at both ends in the width direction of the first inner rubber 24. Therefore, it is not bonded to the second inner rubber 28. The release member 30 is also formed of a material to which rubber does not adhere, similarly to the release sheet 26. In the present embodiment, a sheet made of reinforced polyethylene is used similarly to the release sheet 26. In the present embodiment, the thickness of the second inner rubber 28 is about 2 mm.

A reinforcing ring 31 is provided at the tip of the second inner rubber 28 in the excavation direction in contact with the side wall 28B.
The reinforcing ring 31 has a rectangular cross section and is vulcanized and bonded to the side wall 28B of the second inner rubber 28. The reinforcing ring 31 of the present embodiment is formed of a steel material. In the present embodiment, the outer diameter is 574 mm, the thickness is 12 mm, and the width is 40 mm.

The second inner rubber 28 and the reinforcing ring 3
A third inner rubber 32 is vulcanized and adhered to the outer peripheral surface of the first rubber member 1. In this embodiment, the thickness of the third inner rubber 32 is about 2 mm.

Reinforcing layers 40 and 42 are vulcanized and bonded to the outer peripheral surface of the third inner rubber 32. These reinforcing layers 4
Reference numerals 0 and 42 are made of a sheet member in which cords such as rayon, nylon, steel, and Kevlar are arranged in parallel to form a cord, and this is covered with rubber, and one end and the other end of the sheet member are formed. Are overlapped, and the overlap dimension, that is, the overlap dimension, is 100 mm in this embodiment.
It has been.

The longitudinal direction of the cords of the reinforcing layers 40, 42 is 0 ° to 4 ° with respect to the propulsion direction (axial direction) of the casing 12.
It is preferable to incline in the range of 5 °, and 0 ° to 10 °
It is more preferable to incline in the range of. In this embodiment, the longitudinal direction of the cord of the reinforcing layer 40 and the longitudinal direction of the cord of the reinforcing layer 42 are each inclined at 10 ° with respect to the axial direction of the casing 12, and the cord of the reinforcing layer 40 and the reinforcing layer The cords of 42 have the inclined directions opposite to each other, and the cords cross each other.

On the outer periphery of the reinforcing layers 40 and 42, an outer peripheral rubber 4 is provided.
4 is vulcanized and adhered. The thickness of the outer peripheral rubber 44 is
In this embodiment, it is about 2 mm.

A plurality of female threads 46 are formed on the reinforcing ring 31 at predetermined intervals along the circumferential direction. On the other hand, the casing 12 has a round hole 48 at a position facing the female screw 46.
Are formed. A bolt 49 penetrates through the round hole 48 from the inner peripheral side of the casing 12 to the outer side.
2 The third inner rubber 32 and the second inner rubber 28 penetrate and are screwed into the female threads 46 of the reinforcing ring 31.

The air bag 22 is provided with a base 50 for supplying air. This base 50
It is formed in a cylindrical shape, and a flange portion 50A is formed at one end. The base 50 has a flange portion 50 </ b> A embedded in the first inner rubber 24 and an axial end portion in contact with the release sheet 26. In addition, the base 50 penetrates through the second inner rubber 28, the third inner rubber 32, the reinforcing layers 40 and 42, and the outer rubber 44 on the side opposite to the flange portion 50 </ b> A, and the end thereof is formed of the third inner rubber 32. It is flush with the outer surface.

A pipe taper screw (female screw) 52 is formed on the inner periphery of the base 50. The male screw of one of the pipe joints 54 penetrating the casing 12 from the inner circumference side is formed on the pipe taper screw 52. I agree. Pipe fitting 54
A hose 56 to which air is supplied by an air compressor (not shown) is connected to the other end.

The air bag 22 of this embodiment has an axial dimension L of 890 mm and a thickness T of 28 mm.

Next, the operation of this embodiment will be described. The moat 10 is first installed in a stand (not shown). After the moating machine 10 is installed in the pit, the soft duct 17 is arranged outside the casing 12.

Thereafter, a compressor (not shown) is operated to supply compressed air to the air chamber 25 of the air bag 22. When the compressed air is supplied to the air chamber 25, as shown in FIG. 3, the inner peripheral surface of the first inner rubber 24, that is, the inner wall surface of the air chamber 25 is separated from the release sheet 26, and the first inner rubber 240 The portion of the release sheet 26 located on the outside in the axial direction protrudes toward the soft duct 17 side, and the airbag 2
(2) The outer peripheral surface is in close contact with the inner peripheral surface of the soft duct 17, and the soft duct 17 is supported by the casing 12.

Next, the cutter 14 is rotated by a drive unit (not shown), and the rear end of the casing 12 is pressed by a main push jack (not shown) to propel the excavator 10 into the ground. At this time, the rear end of the soft duct 17 is not brought into contact with the original pushing jack. The soft duct 17 is supported by the casing 12 by the airbag 22, and receives only the propulsive force of the casing 12 to propel the inside of the excavated tunnel.

Each time the casing 12 is propelled, the next casing 12 and soft duct 17 are connected, and the excavator 10 is sequentially propelled into the ground. At this time, the air bag 22
May be attached to all the casings 12, or as shown in FIG.

As shown in FIG. 2, when the airbags 22 are attached to a predetermined number of the casings 12, the propulsive force FP applied to the soft duct 17 is increased.
The portion in contact with is the largest, and the thrust decreases with the frictional force with the inner surface of the tunnel toward the propulsion direction. For this reason, the attachment intervals of the air bags 22 are set so that the propulsion force FP of the soft duct 17 does not become zero.

The airbag 22 includes reinforcing layers 40, 4
2, the cord direction is set to the optimum value, so that high-pressure air can be filled to strongly support the soft duct 17. That is, since the cord direction is inclined by 10 ° with respect to the propulsion direction, the radial expansion of the air chamber 25 is allowed and the air chamber 25 can withstand a high internal pressure. Deformation in the direction is suppressed.

Therefore, even if the soft duct 17 receives the large propulsive force FO of the casing 12, the air bag 2
2 and the soft duct 17 do not relatively slide in the axial direction. For this reason, there is no problem that the soft duct 17 is pushed by the original push jack unlike the related art, and the soft duct 17 at the rear end is not deformed or damaged.

The airbag 22 is pulled in the direction opposite to the direction in which the casing 12 is propelled by the frictional force with the soft duct 17 during propulsion. However, since the tear resistance is enhanced by the reinforcing layers 40 and 42, There is no easy puncturing unlike a conventional airbag without a reinforcing layer.

The excavated soil excavated by the cutter 14 is conveyed through the inner pipe 12B by the screw 16 and discharged to the pier.

After the propulsion to the predetermined position, the compressed air in the air chamber 25 is released to the outside air via a hose, and the outer diameter of the air bag 22 is reduced. Thereafter, the soft duct 17 is set in the excavated tunnel by retracting the airbag 22 together with the casing 12 to the standing side.

[Test Example] In order to examine the effect of the present invention,
The relationship between the cord angle of the reinforcing layers 40 and 42 and the propulsive force (thrust force) of the soft duct, and the relationship between the cord angle and the amount of deformation of the airbag during propulsion were examined.

In the test, the soft duct 17 was supported by two air bags 22 filled with an internal pressure of 7.0 kg / cm ² ,
A thrust was applied to the casing 12 with the main push jack, and the thrust acting on the soft duct 17 was measured with a load meter.

Here, the thrust force when the relative displacement between the casing 12 and the soft duct 17 in the axial direction becomes 10 mm due to the deformation of the air bag 22 is shown in Table 1 below. Table 2 below shows the thrust force when sliding out.

In practice, it is preferable that the thrust force of the soft duct 17 be 20 ton or more.

[0040]

[Table 1]

[0041]

[Table 2]

From the test results shown in Tables 1 and 2, it is practically preferable that the cord angle of the reinforcing layers 40 and 42 be 45 ° or less in terms of deformation and propulsion of the airbag 22. it is obvious.

[0043]

According to the air duct for supporting a soft duct of the present invention having the above-described structure, the soft duct is strongly supported from the inside thereof, and the large propulsive force of the casing of the auger screw is reliably applied to the soft duct. It has an excellent effect that it can be produced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an airbag according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an excavator using the airbag according to one embodiment of the present invention.

FIG. 3 is a sectional view of the airbag showing an inflated state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 12 Casing 14 Cutter (tip edge) 16 Screw (Auger screw) 17 Soft duct 22 Airbag (Airbag for supporting soft duct) 40 Reinforcement layer 42 Reinforcement layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuo Okazaki 1-1-38 Hongodai, Sakae-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Keizo Tachinami 1271 Yoshidacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Hideaki Saito Kanagawa Prefecture 2-8-31 Murota, Chigasaki-shi (56) References JP-A-2-26696 (JP, U) JP-A-1-180591 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) ) E21D 9/06 311

Claims (1)

(57) [Claims] 1. An air bag provided on the outer periphery of a casing of an auger screw for transmitting a thrust force of a primary pushing jack to a tip blade, and having a ring-shaped air chamber expandable and contractable therein, inflates the air bag by inflation. A soft duct supporting airbag used in a method of supporting and embedding the soft duct fitted from inside and propelling and embedding the soft duct, wherein the soft duct supporting airbag is 0 ° to 45 ° with respect to a propulsion direction. An airbag for supporting a flexible duct, characterized by having a cord layer made of cords inclined at an angle.