JP2002004785A - Tunnel forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tunnel forming method capable of forming a curved portion of the tunnel with the same segments even though the radius of curvature varies thereby considerably reducing the cost. SOLUTION: This is a tunnel forming method for forming a peripheral wall of an annulus ring-shaped tunnel T by arranging and connecting many segments 1 and 2 in the peripheral direction and axial direction of a tunnel T, the peripheral wall of a straight line portion TS of the tunnel T is formed by arranging and connecting the segments 1 for straight line in the peripheral direction and axial direction, the plural units of the same shaped annulus ring shape segments 2 with the thickness changing continuously in the radial direction are deviated in position and coupled to the peripheral wall of the straight line portion TS, and the segment 1 for straight line is arranged in the peripheral direction to the segments 2 for curving and connected, by repeating this, the peripheral wall of a curved portion TC of the tunnel T curved with a predetermined radius of curvature R can be formed by the segment 2 for the curve and the segment 1 for the straight line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a peripheral wall of an annular tunnel by connecting a number of segments arranged in the circumferential and axial directions of the tunnel.

[0002]

2. Description of the Related Art A tunnel formed by such a method is used to protect a high-voltage electric wire or the like when a high-voltage electric wire or various cables are buried underground. A method that has been frequently used in the related art will be described.

Conventionally, a straight line portion TS of a tunnel T uses two types of straight line segments 1A and 1B and a key segment 1K as shown in FIGS. 7 and 8, for example, divided into six in the circumferential direction. If so, three straight segments 1A and two straight segments 1B and one key segment 1K are connected in the circumferential direction to form an annular wall portion 17A, and the circle is formed. Annular wall 17A
Are connected to form a straight portion TS in which the central axis P of the tunnel T is linear, and each of the segments 1A, 1B, 1K is made of metal such as steel or concrete.

A curved portion TC of the tunnel T uses various types of bending segments 2A, 2B, 2C and a key segment 2K. For example, when the tunnel T is divided into six in the circumferential direction, one is used. Bending segment 2A and key segment 2K, and two bending segments 2
B and 2C are connected in the circumferential direction to form a bending wall portion 17B, and by connecting a plurality of sets of the bending wall portions 17B, the central axis P of the tunnel T is bent at a predetermined radius of curvature R. Each segment 2A, 2B, 2C, 2K forms a curved portion TC, similarly to the above-described straight line portion TS.
Was formed of metal such as steel or concrete.

[0005]

According to the above-mentioned conventional method, there is no particular problem for the straight portion TS of the tunnel T, but for the curved portion TC, the bending segments 2A, 2B, 2C and the key segment are used. The radius of curvature R of the tunnel T is determined by the shape of the curved wall portion 17B formed by 2K. Therefore, when the central axis P of the tunnel T is curved with a different radius of curvature R, it is necessary to form a different shape of the bending wall portion 17B, and moreover, the bending wall portion 17B has various types of bending. Since it is formed by the segments 2A, 2B, 2C and the key segment 2K, it has to be rebuilt from various kinds of bending segments 2A, 2B, 2C having different shapes, which causes an increase in cost. .

[0006] The present invention focuses on such a conventional problem, and its object is to form a curved portion of a tunnel using the same segment even if the radius of curvature is different. Accordingly, it is an object of the present invention to provide a tunnel forming method which can greatly reduce costs.

[0007]

[Structure] According to a first feature of the present invention, as shown in FIGS. 1 to 5, a large number of segments 1 and 2 are connected side by side in the circumferential and axial directions of a tunnel T. Forming a peripheral wall of an annular tunnel T by connecting the straight segments 1 side by side in the circumferential and axial directions of the tunnel T.
And a plurality of annular bending segments 2 of the same shape whose thicknesses A and B continuously change in the radial direction are displaced in the circumferential direction to form a peripheral wall of the linear portion TS.
By connecting the straight segments 1 to the bending segments 2 in the circumferential direction and connecting the same, and repeating this, the bending segments 2 and the straight segments 1 have a predetermined radius of curvature R. This is to form a peripheral wall of a curved portion TC of the curved tunnel T.

A feature of the invention according to claim 2 is that the straight segment 1 is made of synthetic resin.

A feature of the invention according to claim 3 is that the bending segment 2 is made of a synthetic resin.

[0010] As described above, the reference numerals are used for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

According to the first aspect of the present invention, when forming the straight line portion of the tunnel, the straight line segments are connected side by side in the circumferential direction and the axial direction of the tunnel. When forming the peripheral wall and forming the curved portion of the tunnel, multiple annular bending segments of the same shape whose thickness continuously changes in the radial direction are displaced in the circumferential direction and connected to the peripheral wall of the straight portion And
In addition, a straight segment is arranged in the circumferential direction and connected to the bending segment, and the connection is repeated, thereby forming a circumferential wall of a curved portion of a tunnel that is bent at a predetermined radius of curvature by the bending segment and the straight segment. Therefore, various types of curved portions having different radii of curvature can be formed by using the same-shaped curved segment and straight line segment. Therefore, it is possible to freely form curved portions having different radii of curvature simply by preparing a curved segment and a straight line segment having the same shape, and it is possible to significantly reduce costs as compared with the above-described conventional method. .

According to the characteristic feature of the second aspect of the present invention, since the straight segments are made of synthetic resin, the construction is simplified and the cost is reduced by reducing the weight as compared with the conventional metal or concrete segments. Can be achieved.

According to the characteristic feature of the third aspect of the present invention, since the bending segment is made of a synthetic resin, it is lighter in weight and cost can be reduced as compared with the case where the bending segment is made of metal such as steel. it can.

If both the straight segment and the curved segment are made of synthetic resin, the entire tunnel is made of synthetic resin. When the tunnel is used for protecting high-voltage wires, the power loss from the high-voltage wires is reduced. Can also be suppressed. In other words, if the tunnel is made of metal such as steel, the amount of eddy current generated increases and the power loss from the high-voltage wire increases, but the use of synthetic resin reduces the generation of eddy current. In addition, power loss from the high-voltage wires can be suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tunnel forming method according to the present invention will be described with reference to the drawings. The tunnel formed by this method is used for protecting high-voltage electric wires and various cables when the high-voltage electric wires and various cables are buried in the ground, for example, as shown in FIG. Are formed by a straight portion TS having a central axis P of a straight line and a curved portion TC having the central axis P curved with a predetermined radius of curvature R. The straight line portion TS of the tunnel T is formed by connecting the straight line segments 1 shown in FIG. 2 in the circumferential direction and the axial direction of the tunnel T and connecting the straight line segments 1 shown in FIG. ) Is formed by a combination with the bending segment 2 shown in FIG.

The straight line segment 1 is a molded product made of a synthetic resin, preferably a molded product made of a high-rigidity reinforced synthetic resin mixed with a reinforcing material such as glass fiber or carbon fiber.
In a front view shown in FIG. 1, the peripheral wall portion 3 is formed in an arc shape so as to have a predetermined central angle α, and has a width L as shown in FIG. A pair of long side wall portions 4 extending inward and a pair of short side wall portions 5 extending inward along the short side of the peripheral wall portion 3 are integrally provided. A grout-injecting cylinder 6 is protruded from the inner center of the peripheral wall section 3, and the cylinder 6 and each short-side wall section 5 are connected to each other by the long-side reinforcing wall section 7. The long side walls 4 are integrally connected with the short side reinforcing walls 8 respectively.

The short side wall 5 of the straight line segment 1 is located slightly inside from the short side edge of the peripheral wall 3, that is, a part of the peripheral wall 3 from the short side wall 5. It is provided so that it protrudes and a part of each long side wall part 4 may protrude in a triangular shape, and a triangular space is formed outside each short side wall part 5. In one of the triangular spaces, a triangular fitting protrusion 9 is integrally formed from the peripheral wall portion 3 and both long side wall portions 4 forming the triangular space, and the fitting protrusion 9 is connected to the other of the triangular spaces. It is formed so as to fit in a triangular space, and the other space is formed as a fitting recess 1.
0, and in this embodiment,
An annular peripheral wall is formed by connecting seven linear segments 1 in the circumferential direction, and four bolt holes 11 are formed in each long side wall portion 4.

The bending segment 2 is also a molded article made of a synthetic resin, preferably a molded article made of a high-rigidity reinforced synthetic resin mixed with a reinforcing material such as glass fiber or carbon fiber.
As shown in FIG. 4A, a total of 28 through-holes 12 are formed in an annular shape, and a total of 28 through-holes 12 are formed at equal angles around the center Q. As shown in FIG. As shown in (b), the whole is formed in a tapered shape in a side view. In other words, the thicknesses A and B at both ends are formed so as to continuously change from the thicker thickness A to the thinner thickness B. Each of the through holes 12 is configured to have substantially the same size as the bolt hole 11 of the straight segment 1, and circular recesses 13 are provided on both sides of the through hole 12, that is, on both surfaces of the bending segment 2. Figure 4
The small-diameter portion 15 of the joint member 14 shown in FIG.
It is configured to be fitted into.

Next, a method of forming the tunnel T using the straight segment 1 and the curved segment 2 will be described. In order to form the straight line portion TS of the tunnel T, the straight line segment 1 is used, and as shown in FIG.
The fitting projection 9 of the straight segment 1 is fitted into the fitting recess 10 of another straight segment 1, and a total of seven straight segments 1 are connected in the circumferential direction to form the annular wall portion 17. Form. Then, by repeating the above process and sandwiching a sealing material (not shown) between the adjacent annular wall portions 17, the adjacent annular wall portions 17 are connected to each other by using the bolt holes 11 of the straight segment 1. A plurality of straight segments 1 are tightened together by bolts 18 and nuts 19 (see FIG. 5).
Are connected side by side in the circumferential direction and axial direction of the tunnel T to form a circumferential wall of the straight portion TS of the tunnel T.

In order to form the curved portion TC of the tunnel T, as shown in FIG. 5, two bending segments 2 are located at the ends of the peripheral wall of the straight portion TS formed as described above. Toroidal wall 1 composed of straight segments 1
7, the two curved segments 2 are connected to each other while sandwiching the two curved segments 2 between the annular wall portions 17, and are formed repeatedly. At this time, since the bending segment 2 is formed in a tapered shape in which the thicknesses A and B at both ends thereof change continuously, the thicker thickness A side is set as shown in FIG. When they are connected in a state of being overlapped in the same direction, the radius of curvature R of the curved portion TC of the tunnel T becomes the minimum radius, and conversely, the thicker thickness A side and the thinner thickness B side are overlapped. When they are connected in a state of being bent, the radius of curvature R becomes a maximum radius, that is, a straight line. Therefore, in the middle, in other words, by sandwiching the two bending segments 2 with their positions shifted in the circumferential direction, the curvature radius R can be set to a desired radius between the minimum radius and the maximum radius. it can.

Referring to FIG. 6, the annular wall 1 formed by the straight segments 1 will be described in detail.
7 is L, the outer diameter is D, the thicker thickness of the bending segment 2 is A, the thinner thickness is B, the outer diameter is D which is the same as the annular wall portion 17, and the curved portion TC of the tunnel T is Radius of curvature R
Assuming that the required number of sets of one annular wall portion 17 and two bending segments 2 is X, from the outer peripheral length and inner peripheral length of the curved portion TC,

[0022]

2π ｛R + (D / 2)｝ = (L + 2A) X 2π ｛R- (D / 2)｝ = (L + 2B) X When X is obtained from these two equations,

[0023]

X = πD / (AB), and the number of sets X required to form an annular tunnel having a radius of curvature R can be obtained by calculation. Therefore, for example, in the case of bending at an angle of 120 degrees, the number of sets of X / 3 is required, and in the case of bending at an angle of 90 degrees, the number of sets of X / 4 is required. The number of straight segments 1 and the number of bending segments 2 required to form the portion TC can be obtained by calculation. Then, by substituting X of [Equation 2] into [Equation 1] to obtain R,

[0024]

R = D (L + A + B) / 2 (AB), where the radius of curvature R of the curved portion TC of the tunnel T is the width L and the outer diameter D of the annular wall portion 17, and the thickness of the bending segment 2. If these values are determined as a function of A and B and the outer diameter D, the minimum radius of curvature R of the curved portion TC of the tunnel T can be obtained by calculation.

For example, when the outer diameter D is 1780 mm (1.78 mm)
m), the width L is 600 mm (0.6 mm).
m) and a thickness A of 40 mm (0.
04m), when using the bending segment 2 having a thickness B of 10 mm (0.01 m), by overlapping the thicker thickness A sides of the two bending segments 2 with each other,

[0026]

## EQU4 ## R = 1.78 (0.6 + 0.04 + 0.01)
/2(0.04-0.01)≒19.3(m), and the minimum radius of curvature R can be set to about 19.3 m. The two bending segments 2 are shifted in the circumferential direction. , (A + B) and (AB), the curvature radius R of the curved portion TC of the tunnel T can be changed and adjusted to a desired value.

In forming the curved portion TC of the tunnel T, at least four joint members 14 are used between the two bending segments 2, that is, each divided portion divided into four. The joint member 1 is used between adjacent recesses 13 by using one joint member 14 at a time.
4 and the small-diameter portion 15 is inserted between the through-holes 12 so as to prevent the displacement of the two bending segments 2 in the circumferential direction.
1 and the through holes 12 of the bending segment 2 are used to fasten the annular wall portions 17 to each other with a plurality of bolts 18 and nuts 19 to form a curved portion TC of the tunnel T. Thus, the straight portion TS and the curved portion T of the tunnel T
C, and if grout needs to be injected between the peripheral wall of the straight portion TS and the curved portion TC and the underground, grout is injected by piercing a hole in the grout injection cylinder 6, The construction of the tunnel T is completed.

[Other Embodiments] (1) In the previous embodiment, an example was shown in which the straight segment 1 and the curved segment 2 were formed of a synthetic resin. It can be made of concrete or concrete,
The bending segment 2 can also be formed of metal such as steel.

(2) In the above embodiment, seven linear segments 1 are connected in the circumferential direction to form the annular wall portion 17.
Although an example of forming the annular wall portion 17 has been described, the annular wall portion 17 can be formed by six or less or eight or more straight segments 1 depending on the size of the outer diameter D of the tunnel T or the like. Further, a total of 28 bolt holes 1 are formed in the annular wall portion 17 formed by the straight segment 1 and the bending segment 2.
Although the example in which the holes 1 and the through holes 12 are provided has been described, the number of the bolt holes 11 and the through holes 12 can be appropriately changed according to the outer diameter D of the tunnel T and the like. Furthermore, although the example in which the curved portion TC is formed by sandwiching the two bending segments 2 between the annular wall portions 17 is shown, three or more bending segments 2 are formed between the annular wall portions 17. The curved portion TC can be formed by sandwiching it.

[Brief description of the drawings]

FIG. 1 is a plan view showing a construction state of a tunnel.

FIG. 2 is a perspective view of a straight line segment.

FIG. 3 is a front view showing a connected state of straight segments.

FIG. 4 is an explanatory view of a bending segment, (a) is a perspective view of the bending segment, (b) is a cross-sectional view of the bending segment, and (c) is a perspective view of a joint member.

FIG. 5 is a perspective view of a straight line segment and a curved segment showing a construction state of a tunnel.

FIG. 6 is an explanatory view of a curved portion of a tunnel.

FIG. 7 is a perspective view showing a conventional technique.

FIG. 8 is a plan view showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Straight line segment 2 Curve segment A, B Thickness of curve segment R Curvature radius of curved part T Tunnel TS Straight part of tunnel TC Curved part of TC tunnel

Claims (3)

[Claims] 1. A tunnel forming method for forming a circumferential wall of an annular tunnel by connecting a number of segments in a circumferential direction and an axial direction of a tunnel, wherein the straight segment is formed in a circumferential direction and an axial direction of the tunnel. The peripheral wall of the straight portion of the tunnel is formed by connecting side by side, and a plurality of annular bending segments of the same shape whose thickness continuously changes in the radial direction are displaced in the circumferential direction to form a peripheral wall of the linear portion. The peripheral wall of the curved portion of the tunnel which is connected and connected to the bending segment by arranging the straight line segments in the circumferential direction and repeating the same, by repeating the bending segments and the straight line segments with a predetermined radius of curvature. Forming method for forming a tunnel. 2. The method according to claim 1, wherein the straight segment is made of a synthetic resin. 3. The method for forming a tunnel according to claim 1, wherein the bending segment is made of a synthetic resin.