JPH09195671A - Construction method of shield tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reversing of an entrance packing caused by a step difference of a skin plate of a shield and a ring of a segment. SOLUTION: A ring entrance packing 20 is installed on a pit mouth, and a plural number of propulsive jacks 22 are arranged. A first type ring 30 is assembled in the rear of a shield jack 26 of a shield 16 and it is propelled by the propulsive jacks 22. After propulsion by one stroke, a second type ring 32 an outside diameter of which is materially equal to an outside diameter of a skin plate of the shield 16 is assembled between the first type ring 30 and the propulsive jacks 22 by contracting the propulsive jacks 22, and it is propelled by the propulsive jacks 22. Additionally, a third type ring 44 is assembled between the second type ring 32 and the propulsive jacks 22, and it is propelled by the propulsive jacks 22. The shield is propelled by the shield jack 26 after the second type ring 32 reaches the entrance packing 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a shield tunnel, and more particularly to a method for constructing a shield tunnel for improving the sealing performance at the entrance of a shaft where a shield starts.

[0002]

Shield tunnels formally excavate the ground by means of shields and propel said shields, while at the rear of the shields a plurality of segments are circumferentially arranged and interconnected. The structure is constructed by assembling the rings and connecting the rings that are adjacent to each other in the axial direction to each other.However, because water pressure and earth pressure are working in the ground where the shield propels, the shaft entrance of the vertical shaft where the shield starts A ring-shaped entrance packing is attached to. This entrance packing is curved in the direction of its propulsion due to the propulsion of the shield, and the elasticity of this curvature causes the inner peripheral surface of the entrance packing to contact the outer peripheral surface of the tubular skin plate of the shield.
The skin plate contacts the outer peripheral surface of the ring exposed in the ground. However, since the ring that is the liner of the tunnel has a smaller diameter than the skin plate of the shield, there is a step at the location where the ring emerges from the skin plate. As a result, when the shield propels the end of the skin plate away from the entrance packing, the entrance packing may be elastically restored by the step, and the momentum may reverse the direction of the curve. In this inverted state, the sealing function is lost, so measures are taken to prevent the inversion.

For example, there is a sealing device having a seal ring which is formed in a cylindrical shape having substantially the same diameter as the shield and has a packing which contacts the ring of the segment on the inner circumference (Japanese Patent Laid-Open No. 4-80598). In this sealing device, the seal ring is connected to the rear end of the shield and conveyed to the wellhead, and then remains at the wellhead.

[0004]

When the shield is in a vertical shaft, it is mounted on a rail provided in the vertical shaft to maintain a predetermined level. Therefore, when a seal ring such as the seal device is provided, it is necessary to provide a fan-shaped notch at a portion of the rail, and it is difficult to secure the sealing property of this portion.

The present invention provides a method for constructing a shield tunnel which prevents the entrance packing from being inverted due to a step between the skin plate of the shield and the ring of the segment without providing a special sealing device.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a reaction force reception,
The shield is excavated from the shaft having a wellhead through which the shield will pass and the shield is propelled and the plurality of segments are circumferentially arranged behind the shield, and the segments are connected to each other to form a ring. assembly,
It is a method of constructing a tunnel in which rings that are adjacent to each other in the axial direction are connected to each other to form a liner of the tunnel.
First, an annular entrance packing is attached over the entire circumference of the wellhead, and a plurality of propulsion jacks are arranged in front of the reaction force receiver of the shaft. Then, at least one ring of the first type is assembled by the plurality of segments at a rear portion of the shield jack of the shield having a tubular skin plate and a plurality of shield jacks disposed inside the skin plate. .
Then, the propulsion jack is applied to the first type ring, and the first type ring and the shield are propelled by the propulsion jack. After the completion of the one-stroke propulsion by the propulsion jack, the propulsion jack is contracted to provide an outer diameter between the ring of the first type and the propulsion jack, and an outer diameter of the skin plate that is equal to an outer diameter of the skin plate. Assembling a ring of substantially the same type and applying the propulsion jack to the ring of the second type to propel the ring of the second type, the ring of the first type and the shield by the propulsion jack. To do. After the completion of the one-stroke propulsion by the propulsion jack, the propulsion jack is retracted and the second
A third type ring is assembled between the type ring and the propulsion jack by a plurality of temporary assembly segments, and the propulsion jack is applied to the third type ring, and the third type ring and the second type ring are assembled. The ring, the first type ring, and the shield are propelled by the propulsion jack. After the completion of the one-stroke propulsion by the propulsion jack, the propulsion jack is contracted to assemble another ring of the third type between the third type ring and the propulsion jack, and the propulsion jack is connected to the first propulsion jack. A plurality of third type rings for the three type rings, the second type ring, and the first type
Repeatedly propelling the type of ring and the shield with the propulsion jack. Stopping the propulsion by the propulsion jack when the second type ring reaches the entrance packing, and then propelling the shield by the shield jack.

In carrying out the method for constructing the tunnel, it is preferable that the clearance between the skin plate of the shield, the ring of the first type and the ring of the second type is closed by a sealing means.

[0008]

[Operation and Effect] When the shield reaches the entrance packing, the entrance packing is curved in the propelling direction of the shield, and the inner peripheral surface thereof contacts the outer peripheral surface of the shield skin plate. The propulsion jack propels the shield and multiple rings until the second type ring reaches the entrance packing, and the shield jack propels the shield after the second type ring consisting of the expanded segment reaches the entrance packing. . As a result, the second type of ring is held fixed to the entrance packing.

On the inner surface of the entrance packing, until the second type ring reaches the entrance packing,
Although it is in contact with the outer peripheral surface of the skin plate of the shield,
The edge of the skin plate comes off the entrance packing,
When the second type ring tries to reach the entrance packing, it comes into contact with the outer peripheral surface of the second type ring. As a result, the curved portion of the entrance packing is not substantially restored by elasticity, and the entrance packing is not reversed due to the momentum of restoration. As a result, the safety of constructing a shield tunnel is significantly improved.
Further, since the second type ring prevents substantial restoration of the entrance packing, the length of the curved portion of the entrance packing can be shortened.

According to a preferred embodiment, the front end of the entrance packing is separated from the skin plate because the clearance between the skin plate of the shield, the ring of the first type and the ring of the second type is closed by the sealing means. When transferring to the second type ring, it is possible to prevent water or earth and sand from entering the inside of the skin plate from the ground.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION
Reaction force receiving and excavating the ground with a shield from a vertical shaft having a wellhead through which the shield will pass and propelling the shield and arranging a plurality of segments in the circumferential direction behind the shield, and mutually. The rings are connected to each other to assemble the rings, and the rings positioned adjacent to each other in the axial direction are connected to each other to form a liner of the tunnel. Actually, while arranging the plurality of segments in the circumferential direction, the segments that are adjacent to each other in the axial direction are connected to each other,
In addition, segments that are adjacent to each other in the circumferential direction are connected to each other to gradually construct a tubular tunnel. However, formally, it can be thought of as connecting the rings axially to build a tunnel. For convenience of explaining the method of the present invention, it is stated that the rings are connected in the axial direction to construct the tunnel, but this does not mean that the actual construction direction is as described above.

The shaft itself can be constructed by a known method. The shaft has a tunnel entrance where the shield starts toward the ground, and an annular entrance packing is installed over the entire circumference of the tunnel. The entrance packing is usually a single rubber plate formed in an annular shape, but it is also possible to use a large number of thin wires that are bundled and overlapped to form an annular packing. In its installed state, the entrance packing has an inner diameter smaller than the outer diameter of the skin plate of the shield.

After mounting the entrance packing or in parallel with the mounting, a plurality of propulsion jacks are arranged at equal intervals in the circumferential direction in front of the reaction force receiver of the shaft, and the end portions of the propulsion jacks are arranged. Apply to the reaction force. The propulsion jack propels the shield and the plurality of rings until a second type ring described below reaches the entrance packing. The stroke of the propulsion jack is 1200 mm, for example.
It can be.

The rear portion of the shield jack of the shield having a tubular skin plate and a plurality of shield jacks arranged inside the skin plate,
Assembling at least one first type ring with the plurality of segments. To assemble the ring,
Use the erector inside the shield. This type 1 ring is exposed to the ground by the propulsion of the shield and becomes the tunnel liner as it is. This point is different from the second type ring and the third type ring described later. The first type of ring needs to be aligned from the shield jack to the substantial rear edge of the skin plate, so depending on the distance from the shield jack to the rear edge of the skin plate, it may be one ring or two rings. It is. In the case of two rings, the two rings are connected in the axial direction. In either case, the ring is assembled so that the rear end face of the first type ring projects slightly rearward from the rear end of the shield skin plate. The axial length of the first type ring is, for example, 10
It can be 00 mm.

After assembling the ring of the first type in the shield, when the end portion of each of the propulsion jacks is applied to the end face of the ring of the first type to exert a thrust force on the ring of the first type, the thrust force is , To the shield via a first type ring and shield jack. Thereby, the first type ring and the shield are propelled by the propelling jack. After the completion of the one-stroke propulsion by the propulsion jack, the propulsion jack is contracted so that the outer diameter is substantially equal to the outer diameter of the skin plate between the first type ring and the propulsion jack due to the plurality of enlarged diameter segments. Assemble a second type of ring that is equal to each other.

In the second type ring, when the shield and the plurality of rings are propelled by the propelling jack, the inner peripheral surface of the curved portion of the entrance packing is separated from the outer peripheral surface of the skin plate of the shield to the outer peripheral surface of the second type ring. It's like being able to move smoothly. To this end, the outer diameter of the second type ring is substantially equal to the outer diameter of the shield skin plate, and the clearance from the rear end of the skin plate to the front end of the second type ring is the axis of the curved portion of the entrance packing. It is preferably shorter than the directional length. In practice, there may be a slight difference between the outer diameter of the shield and the outer diameter of the second type ring,
This difference should be smaller than the step between the skin plate and the ring of the first type. The clearance between the rear end of the skin plate, the ring of the first type and the ring of the second type is closed by a sealing means. The segments for the second type of ring can be made of steel as well as reinforced concrete. However, in the case of reinforced concrete, since it is necessary to form only the second type segment, it is advantageous to use steel for cost reasons. The axial length of the second type ring is 400-60
It can be set to 0 mm.

After assembling the second type ring, the propelling jack is applied to the second type ring, and the second type ring, the first type ring, and the shield are connected by the propelling jack. After propelling and completing one stroke of propulsion by the propulsion jack, the propulsion jack is retracted to assemble a third type ring between the second type ring and the propulsion jack with a plurality of temporary assembly segments.

The third type ring is used only to reach the second type ring to the entrance packing. Therefore, rather than using a dedicated segment, it is better to assemble the ring of the third type using the same segment as the liner of the tunnel, which is the same as that used for the ring of the first type. It is convenient because it can be reused as. The ring of the third type and the ring of the second type can be assembled using a crane in a shaft. Regarding the third type ring, some segments may be removed to deal with the discharge of excavated earth and sand or the arrangement of the power supply wire for the shield, etc. In this case, it is not a ring exactly However, in this specification, the term "type 3 ring" is used to mean a ring excluding some segments.

After assembling the ring of the third type, the propelling jack is applied to the ring of the third type, the ring of the third type, the ring of the second type, and the ring of the first type, The shield is propelled by the propelling jack for one stroke. After the propulsion, the propulsion jack is retracted to assemble another third type ring between the third type ring and the propulsion jack, and the propulsion jack is applied to the rearmost third type ring to form a plurality of rings. Propulsion of the third type ring, the second type ring, the first type ring, and the shield by the propulsion jack is repeated. The number of repetitions is determined by the size of the shaft and the axial length of the third type ring.

When the shield reaches the entrance packing during the above-mentioned repetition, the entrance packing is bent in the propelling direction of the shield, and the inner peripheral surface thereof contacts the outer peripheral surface of the skin plate of the shield. When the shield enters the ground and becomes in the state of being affected by water pressure and earth pressure, the following is how to assemble the ring of the third type. While keeping a plurality of propulsion jacks arranged at equal intervals in the circumferential direction in a state in which thrust is applied, that is, in a stretched state, the propulsion jack in this space is contracted so that a space for one segment can be secured, Keep the other propulsion jacks extended. Then, guide the segment to the space, extend the compressed propulsion jack to support the segment, then similarly install the segment that will be located adjacent to the segment, and bolt the adjacent segments to each other. To do. When one ring is formed by repeating the same operation, the shield is propelled together with the plurality of rings.

When the second type ring reaches the entrance packing, the propulsion by the propulsion jack is stopped, and thereafter, as in the ordinary shield construction method,
The shield jack propels the shield. When the shield propelling couples the rings of the first type in the axial direction and the reaction force of the propulsion of the shield can be received by the ground through the ring of the first type, the ring of the second type remains as it is. It is buried in the ground and the ring of the third type is disassembled, or the ring of the second type and the ring of the third type are disassembled.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tunnel construction method will be described with reference to FIGS. 1 to 4, in which a shield 16 is launched from a vertical shaft 14 having a reaction force receiver 10 and a wellhead 12 through which the shield passes, and the shield 16 is used. Excavating the ground 18 and propelling the shield 16, arranging a plurality of segments of a structure known per se in the circumferential direction behind the shield 16 and interconnecting them to assemble a ring, axially next to each other. The located rings are interconnected to form the tunnel liner.

The shaft 14 is constructed according to a method known per se, and the reaction force receiver 10 and the wellhead 12 are provided in the shaft 14. An annular entrance packing 20 is attached over the entire circumference of the well hole 12 of the shaft 14, and a plurality of propulsion jacks 22 are arranged in front of the reaction force receiver 14 of the shaft 14. The propulsion jack 22 is a hydraulic cylinder device.

The shield 16 is a cylindrical skin plate 2
4 and a plurality of shield jacks 26 arranged at equal intervals inside the skin plate 24, which is a structure known per se. Shield 16 shaft 14
It is preferred that the plurality of propulsion jacks 22 be placed in place and secured to one another to form an independent structure before being guided inward. The shield 16 rests on the rail 28 and is in place, facing the wellhead 12.

After the propulsion jack 22 is in place, at least one first type ring 30 is assembled by the plurality of segments at the rear portion of the shield jack 26 of the shield 16 (FIG. 1). An erector (not shown) installed in the shield 16 is used for this assembly. The ring 30 of the first type becomes the liner of the tunnel as it is when the shield 16 propels the ground 18.

The propulsion jack 22 is connected to the ring 3 of the first type.
When the thrust is applied to the ring 30 of the first type by hitting 0, the thrust is transmitted from the ring 30 of the first type to the shield 16 via the shield jack 26, and the ring 30 of the first type and the shield 16 are propelled by the jack. It is propelled a distance equivalent to one stroke of 22.

After the propelling jack 22 completes the propelling of one stroke, the propelling jack 22 is contracted and the outer diameter of the skin plate 24 is reduced between the first type ring 30 and the propelling jack 22 by a plurality of expanding segments. Assemble a second type ring 32 that is substantially equal in outer diameter (FIG. 2).

As shown in FIG. 5, the skin plate 24
, The first type ring 30 and the second type ring 3
A clearance is usually formed between the two. Therefore, the gap is closed by the sealing means 34. The sealing means 34 can be formed by a cylindrical auxiliary skin plate 36, or by a filler material 38 such as mortar or urethane, or both. Auxiliary skin plate 3
6 has an inner diameter larger than the outer diameter of the skin plate 24 and the outer diameter of the ring 32, and is welded to the outer peripheral surface of the ring 32 in a sealed manner. And the auxiliary skin plate 3
6 is sealed by a sealing material 40 and is movable relative to the skin plate 24. The filling material 38 extends in the circumferential direction and fills the clearance between the skin plate 24, the ring 30, and the ring 32. As a result, in combination with the original wire brush 42 of the skin plate 24 that comes into contact with the ring 30, water or earth and sand are prevented from entering the skin plate 24.

After assembly of the ring 32, the propulsion jack 22
Is applied to the ring 32 of the second type and a thrust is applied to the ring 32 of the second type, the thrust is transmitted to the shield 16 via the ring 32 of the second type, the ring 30 of the first type and the shield jack 26, The second type ring 32, the first type ring 30, and the shield 16 are propelled by a distance corresponding to one stroke of the propulsion jack 22.

After the propelling jack 22 completes the propelling of one stroke, the propelling jack 22 is retracted and the third type ring 44 is assembled between the second type ring 32 and the propelling jack 22 by a plurality of temporary assembly segments. ,
The propulsion jack 22 is applied to the ring 44 of the third type to exert a thrust force on the ring 44 of the third type. As a result, the thrust is the third type ring 44, the second type ring 3
2, first type ring 30 and shield jack 2
6 is transmitted to the shield 16, and the third type ring 44, the second type ring 32, and the first type ring 3 are transmitted.
0 and the shield 16 are propelled a distance equivalent to one stroke of the propulsion jack 22.

After one stroke of propulsion by the propulsion jack 22 is completed, the propulsion jack 22 is retracted and a third type ring 44 is assembled between the third type ring 44 and the propulsion jack 22 to propel the jack. 22 is applied to the ring 44 of the third type and the plurality of rings 44 of the third type, the ring 32 of the second type, the ring 30 of the first type and the shield are propelled by the propulsion jack 22 repeatedly (FIG. 3).

While the propulsion by the propulsion jack 22 is repeated, the leading portion of the shield 16 becomes the entrance packing 2.
When it reaches 0, the entrance packing 20 is bent in the propelling direction of the shield 16 (FIG. 3). When it is further propelled and the second type ring 32 reaches the entrance packing 20 (FIG. 4), the propulsion by the propulsion jack 22 is stopped. Then the first type ring 30
Another ring 30 of the first type is assembled between the ring 32 and the ring 32 of the second type, and the shield 16 is propelled by the shield jack 26. When the reaction force of the shield jack 26 is received by the friction between the plurality of rings 30 and the ground 18, the temporary ring 44 is disassembled and the propulsion jack 22 is removed. The ring 32 is directly buried in the ground or dismantled.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a method of constructing a shield tunnel according to the present invention.

FIG. 2 is a schematic diagram showing a method of constructing a shield tunnel according to the present invention, showing a state in which the shield is further pushed from the position of FIG.

FIG. 3 is a schematic diagram showing a method of constructing a shield tunnel according to the present invention, showing a state in which the shield is further propelled from the position shown in FIG. 2 and the leading portion of the shield reaches the entrance packing.

FIG. 4 is a schematic diagram showing a method of constructing a shield tunnel according to the present invention, showing a state in which the shield is further propelled from the position of FIG. 3 and the second type ring is in a fixed position with respect to the entrance packing. Shows.

FIG. 5 is a sectional view showing a part of an embodiment of the sealing means.

[Explanation of symbols]

 10 Reaction force reception 12 Well mouth 14 Vertical shaft 16 Shield 18 Ground 20 Entrance packing 22 Propulsion jack 24 Skin plate 26 Shield jack 30 First type ring 32 Second type ring 44 Third type ring

Claims (2)

[Claims] 1. A ground is excavated by a shield from a vertical shaft having a reaction force receiver and a well hole through which the shield passes, and the shield is propelled, and a plurality of segments are circumferentially arranged behind the shield. , And the rings are connected to each other to assemble the rings, and the rings adjacent to each other in the axial direction are connected to each other to form a liner of the tunnel.
A method of constructing a tunnel, wherein an annular entrance packing is attached over the entire circumference of the wellhead, a plurality of propulsion jacks are arranged in front of the reaction force receiver of the shaft, a tubular skin plate, and this skin Assembling at least one first type ring with the plurality of segments at a rear portion of the shield jack of the shield having a plurality of shield jacks disposed inside a plate; Propelling the ring of the first type and the shield against the ring by the propulsion jack, and after the propulsion of one stroke by the propulsion jack is completed, the propulsion jack is contracted to the ring of the first type. Multiple expanding segments between the propulsion jack Assembling a second type ring having a diameter substantially equal to the outer diameter of the skin plate, applying the propulsion jack to the second type ring, the second type ring, and the first type ring; ,
Propulsing the shield with the propulsion jack, and after completing one stroke of propulsion with the propulsion jack, retracting the propulsion jack to provide a plurality of temporary assembly segments between the second type ring and the propulsion jack. Assembling a third type ring by applying the propulsion jack to the third type ring, the third type ring, and the second type ring;
Propelling the ring of the first type and the shield by the propulsion jack, and after the propulsion of one stroke by the propulsion jack is completed, the propulsion jack is contracted and the ring of the third type and the propulsion jack are Another third type ring is assembled between the two, and the propulsion jack is applied to the third type ring to form a plurality of third type rings and the second type ring.
Repeating propulsion of the ring of the first type, the ring of the first type, and the shield by the propulsion jack; when the ring of the second type reaches the entrance packing, the propulsion by the propulsion jack is stopped. And then propelling the shield with the shield jack. 2. The skin plate of the shield,
The method according to claim 1, further comprising closing a clearance between the first type ring and the second type ring with a sealing means.
The method of constructing the tunnel described in.