JP7149714B2 - tunnel shoring - Google Patents

Description

The present invention relates to tunnel shoring, and more particularly to the structure of telescopic tunnel shoring.

The NATM construction method (New Austrian Tunneling Method) is known as a construction method for constructing tunnels. The NATM construction method is based on the concept of maintaining the stability of the tunnel by effectively utilizing the supporting capacity and strength of the ground. , is a method of constructing a tunnel structure integrated with the ground.

When constructing a tunnel in the NATM construction method, an arch-shaped tunnel support is installed in the tunnel. At that time, the tunnel support may be subjected to expansive soil pressure due to deformation of the natural ground created by excavating the tunnel. Tunnel shoring receives a load in the direction in which the arch-shaped shoring material compresses due to expanded earth pressure. It is configured to be held (see, for example, Patent Literature 1).

JP-A-2000-303797

The tunnel shoring disclosed in Patent Document 1 is constructed by slidably fitting both leg members having a U-shaped cross section and a crown member having a U-shaped cross section in an arch-shaped portion. The leg members and the crown member are sandwiched and tightened by an inverted hat-shaped saddle and a U-bolt. As a result, the leg members and the crown member do not relatively slide up to a predetermined earth pressure load, but when they receive the predetermined earth pressure load, they begin to slide relatively and are displaced to absorb the expanded earth pressure of the tunnel. do. However, in the case of the tunnel shoring disclosed in Patent Document 1, the tunnel shoring is configured to be compressible according to the expansion of the ground, but if the tunnel is expanded by the expansion of the ground, , the joint portion fastened by the inverted hat-shaped saddle and the U-bolt had to be loosened again to match the tunnel, and there was a problem that it took a lot of man-hours to correct.

In addition, the tunnel shoring requires installation of a plurality of shoring materials in the direction in which the tunnel extends, and it is necessary to align adjacent shoring materials in the height direction when installing. In the case of the tunnel shoring disclosed in Patent Document 1, a plurality of independent shoring materials must be installed while aligning their positions, and there is a problem that the installation takes a lot of man-hours. Furthermore, if the ground on which the tunnel shoring is to be installed is soft, it is necessary to add tethers to connect the shoring materials together to prevent the shoring materials from sinking, which requires a lot of man-hours during installation. There was a problem of taking

The present invention is intended to solve the above-mentioned problems, and provides a tunnel support that can cope with the expansion of natural ground and can reduce the number of man-hours for installing a plurality of support materials in the direction in which the tunnel extends. for the purpose.

A tunnel shoring according to the present invention is a tunnel shoring having shoring materials arranged along the wall surface of a tunnel to form an arch portion, and a joint portion in which the shoring material slides in an expandable and contractible manner, The joint portion is configured by alternately stacking ends of two shoring materials extending from one end of the arch portion and ends of two shoring materials extending from the other end of the arch portion.

A tunnel shoring according to the present invention is a tunnel shoring having shoring materials arranged along the wall surface of a tunnel to form an arch portion, and a joint portion in which the shoring material slides in an expandable and contractible manner, The shoring members include a first shoring member extending from one end of the arch portion, a second shoring member extending from the other end of the arch portion, and a tunnel to the first shoring member. a third shoring material spaced apart in the direction in which the tunnel extends and a fourth shoring material spaced in parallel to the second shoring material in the direction in which the tunnel extends; wherein the first shoring material and the third shoring material are connected to each other by a tie member to form a first segment, and the second shoring material and the fourth shoring material are connected to each other It further comprises a third segment connected by a bridging member and constituting a second segment and having the same structure as the first segment, and a fourth segment having the same structure as the second segment, wherein the joint part is the arch In the middle of the section, the ends of the first shoring material of the first segment and the second shoring material of the second segment are overlapped in parallel, and the second shoring material of the second segment is The first shoring material of the first segment and the third shoring material of the third segment are sandwiched and overlapped, and the third shoring material of the third segment overlaps the third shoring material of the second segment. The first shoring material of the first segment and the third shoring material of the third segment are sandwiched and overlapped between the second shoring material and the fourth shoring material of the fourth segment. The second shoring material of the second segment and the fourth shoring material of the fourth segment are configured to slide in directions in which the arch portions expand and contract relative to each other .

With the above structure, even when the ground expands and a load is applied to the tunnel shoring, the shoring material is able to follow and shrink, thereby preventing the shoring material from buckling and being damaged. It can be installed inside a tunnel. In addition, by adjusting the spacing of the shoring materials in the direction in which the tunnel extends, the tunnel shoring can set the installation spacing of the shoring materials according to the condition of the ground and improve the ease of assembly. .

1 is a perspective view illustrating the overall structure of a tunnel shoring according to Embodiment 1; FIG. FIG. 2 is a schematic view of the arch portion of the tunnel support according to Embodiment 1 as viewed from above; FIG. 3 is a view showing the AA section of the arch portion of FIG. 2; 4 is an enlarged perspective view of the joint portion of FIG. 3; FIG. FIG. 2 is a schematic diagram illustrating a state in which the tunnel support structure according to Embodiment 1 is installed in a tunnel; FIG. 4 is a diagram for explaining the procedure for installing the tunnel support according to Embodiment 1;

An embodiment of the tunnel support will be described below. In addition, the form of drawing is an example and does not limit this invention. In addition, the same reference numerals in each drawing are the same or equivalent, and this is common throughout the specification. Furthermore, in the drawings below, the size relationship of each component may differ from the actual size. In each figure, those with subscripts (e.g. 11a etc.) will have subscripts if there are no subscripts (e.g. 11 etc.) in the following description. shall be collectively referred to as

Embodiment 1.
FIG. 1 is a perspective view illustrating the overall structure of a tunnel support 100 according to Embodiment 1. FIG. FIG. 1 omits the detailed structure of each part of the tunnel support. A tunnel shoring 100 according to Embodiment 1 is constructed by arranging a plurality of shoring bodies 10 in which an arch portion 50 and an inverted portion 40 are joined together in the direction in which a tunnel extends. In FIG. 1 , as an example, three shoring bodies 10 are arranged side by side, and the shoring bodies 10 are connected by a joint portion 30 and an invert connection member 41 . The tunnel shoring 100 may be configured by arranging more shoring bodies 10 .

The tunnel support 100 is installed, for example, in a mountainous tunnel excavated by the New Austria Tunneling Method (NATM), and protects workers from falling off the walls of the tunnel. This improves the safety of workers during tunnel installation work.

The arch part 50 is a part arranged along the upper arch-shaped wall surface of the excavated tunnel. The inverted portion 40 is a portion arranged along the bottom surface of the tunnel. The arch portion 50 and the inverted portion 40 are connected at their ends by joining means such as bolts and nuts or welding to form the support structure 10 . The inverted section 40 is arranged at the bottom of the tunnel and covered with cast concrete or the like to serve as a reinforcing structure for the bottom of the tunnel.

The arch portion 50 is composed of a plurality of shoring materials 11 . A joint portion 20 is formed in the central portion of the arch portion 50 . The joint section 20 is configured such that the plurality of shoring materials 11 that form the arch section 50 slide relative to each other so that the arch section 50 can expand and contract. With this configuration, the arch portion 50 of the tunnel support 100 shrinks when a load is applied to the arch portion 50 from the wall surface of the tunnel due to natural expansion. Therefore, even if a load is applied from the ground, the arch portion 50 of the tunnel support 100 can be prevented from being damaged due to buckling of the support material 11 or the like. In addition, even when the tunnel is further expanded due to the expansion of the natural ground and excavated, the arch portion 50 can be extended in accordance with the expanded tunnel wall surface. This reduces the work of installing the tunnel support 100 again.

FIG. 2 is a schematic top view of the arch portion 50 of the tunnel support 100 according to the first embodiment. FIG. 3 is a diagram showing a section AA of the arch portion 50 of FIG. FIG. 2 shows a state in which four shoring bodies 10 are arranged side by side as an example. The tunnel shoring 100 shown in FIG. 2 is constructed by combining six segments 60A-60F.

(First segment 60A)
Of the segments 60A to 60F forming the tunnel support 100 in FIG. 2, the structure of the first segment 60A will be described. The first segment 60</b>A is formed by connecting the connecting members 31 attached to the two shoring materials 11 . As shown in FIG. 3, the shoring material 11 is an angle steel having an L-shaped cross section. However, the support material 11 is not limited to angle steel, and may be a material having a cross-sectional shape in which one side is a protrusion and the other side is a recess, and the protrusion fits into the recess. may be configured. In Embodiment 1, the support material 11 can be manufactured at low cost by using angle steel. The support material 11 is formed by being bent in the longitudinal direction in an arch shape as shown in FIG. The cross sections of the shoring materials 11 forming the segments 60A to 60F all have the same shape.

As shown in FIG. 3, the first segment 60A is formed by arranging the first shoring material 11a and the third shoring material 11c in parallel. It is configured by connecting connecting members 31 projecting from each of the members 11c. The connecting member 31 is attached to each of the first shoring material 11a and the third shoring material 11c at two locations, but may be provided at one location or at three or more locations.

Also, the distance between the first shoring material 11a and the third shoring material 11c can be changed. In Embodiment 1, the connecting member 31 is provided with three holes 34 . A bolt 32 is passed through a hole 34 provided in a connecting member 31 provided on the first shoring material 11a and a connecting member 31 provided on the second shoring material 11b, and a nut 33 is screwed onto the bolt 32. Fastened and connected. Note that the number of holes 34 is not limited to three. A single hole 34 or a plurality of holes 34 may be provided as long as the length of the connecting portion 30 can be adjusted.

(Second segment 60B)
Among the segments 60A to 60F forming the tunnel support 100 in FIG. 2, the structure of the second segment 60B will be described. The second segment 60B is paired with the first segment 60A, the first segment 60A forming one end of the arched portion 50 and the second segment 60B forming the other end of the arched portion 50. .

The second segment 60B is also formed by connecting the connecting members 31 attached to the two shoring materials 11 in the same manner as the first segment 60A. The second segment 60B is formed by arranging the second shoring material 11b and the fourth shoring material 11d in parallel. It is configured by connecting members 31 to each other. The connection between the bridging members 31 in the second segment 60B is the same as in the first segment 60A, and the distance between the second shoring material 11b and the fourth shoring material 11d can be changed.

The second shoring material 11b forming the second segment 60B is superimposed on the first shoring material 11a of the first segment 60A. That is, the second shoring material 11b has the same cross-sectional shape as the first shoring material 11a. Also, the fourth shoring material 11d is superimposed on the third shoring material 11c of the first segment 60A. That is, the fourth shoring material 11d has the same cross-sectional shape as the third shoring material 11c.

(Third segment 60C and fourth segment 60D)
The third segment 60C has the same structure as the first segment 60A. The fourth segment 60D has the same structure as the second segment 60B. Therefore, the first shoring material 11a of the third segment 60C and the third shoring material 11c of the fourth segment 60D are overlapped. The third shoring material 11c of the third segment 60C and the fourth shoring material 11d of the fourth segment 60D are also superimposed. As shown in FIG. 2, a first segment 60A and a second segment 60B are arranged in pairs in an excavated tunnel, and a third segment 60C and a fourth segment 60D are aligned in the direction in which the tunnel extends. are arranged in pairs. 2, the segment 60E and the segment 60F are arranged side by side in the direction in which the tunnel extends. The segment 60E has the same structure as the first segment 60A, and the segment 60F has the same structure as the second segment 60B. be.

(Joint portion 20)
The joint portion 20 is formed by combining the segments 60A to 60F. First, the joint portion 20A formed by the first segment 60A, the second segment 60B, the third segment 60C, and the fourth segment 60D will be described.

The joint portion 20A includes a first shoring material 11a of the first segment 60A, a second shoring material 11b of the second segment 60B, a third shoring material 11c of the third segment 60C, and a fourth shoring material of the fourth segment 60D. It is formed from the material 11d. First, the central end portion 12b of the arch portion 50 of the second shoring material 11b of the second segment 60B is superimposed on the central end portion 12a of the arch portion 50 of the first shoring material 11a of the first segment 60A. The first shoring material 11a and the second shoring material 11b are arranged so that the protrusion of the first shoring material 11a fits into the recess of the second shoring material 11b. In FIG. 2, the center side end portion 12a and the center side end portion 12b are superimposed so that the longitudinal direction of the shoring material 11 is parallel, and when the arch portion 50 expands and contracts, they slide against each other. It's becoming

In addition, the central end portion 12c of the third shoring material 11c of the third segment 60C is superimposed on the projecting portion side of the central end portion 12b of the second shoring material 11b of the second segment 60B. The second shoring material 11b and the third shoring material 11c are arranged so that the projection of the second shoring material 11b fits into the recess of the third shoring material 11c. In FIG. 2, the center side end portion 12b and the center side end portion 12c are superimposed so that the longitudinal direction of the shoring material 11 is parallel, and when the arch portion 50 expands and contracts, they slide against each other. It's becoming Further, the central end 12d of the fourth shoring material 11d of the fourth segment 60D is superimposed on the protrusion side of the central end 12c of the third shoring material 11c of the third segment 60C. The third shoring material 11c and the fourth shoring material 11d are arranged so that the projection of the third shoring material 11c fits into the recess of the fourth shoring material 11d. In FIG. 2, the center side end portion 12c and the center side end portion 12d are superimposed so that the longitudinal direction of the shoring material 11 is parallel, and when the arch portion 50 expands and contracts, they slide against each other. It's becoming

FIG. 4 is an enlarged perspective view of the joint portion 20A of FIG. In FIG. 4, the periphery of the joint portion 20A is shown cut away. The joint portion 20A includes two shoring materials 11a and 11c extending from one end 51a of the arch portion 50 and two shoring materials 11b and 11d extending from the other end 51b of the arch portion 50, respectively. , 12b, 12c, and 12d are stacked alternately.

That is, in the joint portion 20A, the central end 12b of the second shoring material 11b is sandwiched between the central end 12a of the first shoring material 11a and the central end 12c of the third shoring material 11c. is In the joint portion 20A, the central end 12c of the third shoring material 11c is sandwiched between the central end 12b of the second shoring material 11b and the central end 12d of the fourth shoring material 11d. is With this configuration, the joint portion 20A of the arch portion 50 of the tunnel shoring 100 is composed of shoring materials 11a and 11c extending from one end portion 50a of the arch portion 50 and the other end portion 50b of the arch portion 50. shoring members 11b, 11d extending from are slidably combined with each other. Therefore, the joint portion 20A is configured to be freely stretchable in the longitudinal direction of the shoring material 11, and even when the tunnel becomes narrow due to the expansion of the natural ground and a load compressing the shoring material 11 is applied from the wall surface of the tunnel, It is possible to suppress the material 11 from being damaged due to buckling or the like.

(Invert fixing portion 42)
In FIG. 1, both ends of the arch portion 50 are invert fixing portions 42, and the ends of the invert portion 40 and the shoring material 11 forming the arch portion 50 are connected. The inverted portion 40 and the shoring material 11 may be connected using bolts and nuts, or may be connected by welding. 1, the arch portion 50 of one shoring body 10 is composed of four shoring materials 11, and one end portion 51a and the other end portion 51b of the arch portion 50 are each formed by two shoring members. It is composed of a work material 11 . Thus, the inverted section 40 is connected to the two shorings 11 at one end 51a and the other end 51b of the arch section 50, respectively. The inverted section 40 may be composed of two members, or may be connected to two shoring materials 11 at both ends of one member.

In FIG. 1, when one inverted portion 40 is composed of two members, the inverted portion 40 is formed by the first shoring material 11a and the second shoring material 11b that constitute the segments 60A to 60F in FIG. It is fixed to both ends of one constituent member. Further, the third support material 11c and the fourth support material 11d are fixed to one member that constitutes the inverted portion 40. As shown in FIG. Therefore, for example, the first segment 60A and the second segment 60B in FIG. 2 are connected at the end of the arch portion 50 by a member that constitutes the inverted portion 40 and are integrated. The third segment 60C and the fourth segment 60D of FIG. 2 are similarly integrated. Further, for example, the inverted portion 40 attached to the first segment 60A is fixed to the first shoring material 11a and the second shoring material 11b, the third shoring material 11c and the fourth shoring material. There are two that are fixed to the material 11d. The two inverted parts 40 attached to the first segment 60a are connected by an inverted connecting member 41 as shown in FIG. With this configuration, it is possible to obtain the effect of suppressing the invert portion 40 attached to the first segment 60a from sinking into the soft ground.

(Installation method of tunnel support 100)
FIG. 5 is a schematic diagram illustrating a state in which the tunnel support 100 according to Embodiment 1 is installed inside the tunnel 90. As shown in FIG. FIG. 6 is a diagram for explaining the installation procedure of the tunnel support 100 according to the first embodiment. FIG. 5 is a cross-sectional view taken parallel to the direction in which the tunnel 90 extends, and shows a cross-section including the joint portion 20 .

First, the first segment 60A is installed in the tunnel 90, as shown in FIG. 6(a). After that, it is superimposed on the third shoring material 11c of the first segment 60A and the fourth shoring material 11d of the second segment 60B, and the first shoring material 11a of the first segment 60A and the second shoring material of the second segment 60B are stacked. The second segment 60B is installed so as to overlap 11b. As shown in FIG. 5, the projecting portion of the third shoring material 11c of the first segment 60A fits into the recess of the fourth shoring material 11d of the second segment 60B, and the first shoring material 11a of the first segment 60A The second segment 60B is installed such that the protrusion of the second segment 60B fits into the recess of the second shoring material 11b of the second segment 60B. Since the shoring materials 11 are all formed to have the same cross-sectional shape, the protruding portions of the shoring materials 11a and 11c of the first segment 60A are fitted into the concave portions of the shoring materials 11b and 11d of the second segment 60B. This has the advantage of facilitating alignment between the first segment 60A and the second segment 60B.

As shown in FIG. 6(b), the third segment 60C is then installed. The third segment 60C has the same structure as the first segment 60A. As shown in FIG. 5, the third segment 60C is installed such that the recess of the third shoring material 11c of the third segment 60C fits over the protrusion of the second shoring material 11b of the second segment 60B. In addition, there is a gap of one plate thickness of the shoring material 11 between the third shoring material 11c of the third segment 60C and the first shoring material 11a of the first segment 60A. Since the third segment 60C fits together from the central portion to the end portion 51a, the third segment 60C can be accurately installed with respect to the already installed first segment 60A and second segment 60B.

As shown in FIG. 6(c), the fourth segment 60D is then installed. The fourth segment 60D has the same structure as the second segment 60B. As shown in FIG. 5, the fourth segment 60D is installed such that the recess of the fourth shoring material 11d of the fourth segment 60D fits over the protrusion of the third shoring material 11c of the third segment 60C. The fourth shoring material 11d of the fourth segment 60D and the second shoring material 11b of the second segment have a gap corresponding to the thickness of one sheet of the shoring material 11. Since the first segment 60A, the second segment 60B, and the third segment 60C, in which the fourth segment 60D is already installed, can be installed with high accuracy.

As described above, the tunnel support 100 of Embodiment 1 is formed by arranging the first segment 60A to the fourth segment 60D. are formed by arranging them in sequence. After arranging the first segment 60A to the fourth segment 60D, by repeating the process of arranging the third segment 60C and the fourth segment 60D again, the tunnel support 100 can be further extended.

According to the tunnel support 100 according to Embodiment 1, by providing the above-described configuration, the arch portion 50 is formed by providing the joint portion 20 even if there is expansion of the natural ground from which the tunnel is excavated. Damage such as buckling of the support material 11 can be suppressed. In addition, the tunnel shoring 100 is configured by combining the segments 60, thereby forming the joint portion 20 and facilitating alignment of the segment 60 to be newly installed with the already installed segment 60, thereby improving installation. It is possible to reduce the number of man-hours for alignment. In addition, the joint portion 20 can be assembled without using bolts or the like, and the number of assembly man-hours required for forming the joint portion 20 is reduced, and the installation of the tunnel support 100 is facilitated.

In addition, in the tunnel shoring 100 according to Embodiment 1, the shoring materials 11 forming each segment 60 are connected to each other by the connecting portions 30 . In other words, the shoring materials 11 are connected by the connecting portions 30 between the arch portions 50 adjacent to each other in the direction in which the tunnel extends. Since the joint part 30 can be changed in length, the distance between the shoring materials 11 of each segment 60 can be changed according to the ground condition of the natural ground. Therefore, when the natural ground is soft, it is possible to reduce the distance between the shoring materials 11, etc., and the tunnel shoring 100 can be applied to tunnels 90 formed on various grounds.

The tunnel shoring 100 according to Embodiment 1 includes a joint portion 30 and an invert connection member 41, and the segments 60 are connected by fitting the shoring materials 11 together. With this configuration, the segments 60 constituting the tunnel shoring 100 are relatively unlikely to be displaced from each other, and it is possible to suppress the subsidence of the segments 60 on soft ground.

10 shoring body 11 shoring material 11a (first) shoring material 11b (second) shoring material 11c (third) shoring material 11d (fourth) shoring material 12a central side end Part 12b Center side end 12c Center side end 12d Center side end 20 Joint part 20A Joint part 30 Joint part 31 Joint member 32 Bolt 33 Nut 34 Hole 40 Invert part 41 Invert connection member, 42 Invert fixing part, 50 Arch part, 50a End part, 50b End part, 51a End part, 51b End part, 60 Segment, 60A (First) Segment, 60B (Second) Segment, 60C (Third ) segment, 60D (fourth) segment, 60E segment, 60F segment, 90 tunnel, 100 tunnel shoring.

Claims (14)

A tunnel shoring comprising a shoring material arranged along the wall surface of a tunnel and forming an arch portion, and a joint portion in which the shoring material slides in an extendable and retractable manner,
The joint portion
A tunnel shoring constructed by alternately stacking ends of two shoring members extending from one end of the arch and two shoring members extending from the other end of the arch. The cross-sectional shape of the shoring material is
2. The tunnel shoring according to claim 1, which has a recess on one surface and a projection that fits in the recess on the other surface, and is formed in the same shape. 3. Tunnel shoring according to claim 1 or 2, wherein the shoring material consists of angle steel. Both ends of the arch portion are
The tunnel support according to any one of claims 1 to 3, which is fixed to an invert portion arranged along the bottom surface of the tunnel. The arch portion
A plurality of arranged along the direction in which the tunnel extends,
The shoring material is
The tunnel shoring according to any one of claims 1 to 4, wherein the shoring material of another arch portion adjacent in the direction in which the tunnel extends is connected by a connecting member. The connecting member is
6. The tunnel support according to claim 5, wherein the length of the tunnel can be changed in the direction in which the tunnel extends. A tunnel shoring comprising a shoring material arranged along the wall surface of a tunnel and forming an arch portion, and a joint portion in which the shoring material slides in an extendable and retractable manner,
The shoring material is
a first shoring member extending from one end of the arch;
a second shoring member extending from the other end of the arch;
a third shoring material arranged parallel to and spaced from the first shoring material in the direction in which the tunnel extends;
a fourth shoring member spaced parallel to the second shoring member in the direction in which the tunnel extends;
The first shoring material and the third shoring material are
connected to each other by a connecting member to form a first segment;
The second shoring material and the fourth shoring material are
connected to each other by a tether member to form a second segment;
a third segment having the same structure as the first segment;
a fourth segment having the same structure as the second segment;
The joint portion
In the central portion of the arch portion, the ends of the first shoring material of the first segment and the second shoring material of the second segment are overlapped in parallel, and the second shoring material of the second segment is sandwiched between the first shoring material of the first segment and the third shoring material of the third segment, and the third shoring material of the third segment overlaps the second segment sandwiched between the second shoring material and the fourth shoring material of the fourth segment,
The first shoring material of the first segment, the third shoring material of the third segment, the second shoring material of the second segment, and the fourth shoring material of the fourth segment, Tunnel shoring , wherein the arches are configured to slide relative to each other in telescoping directions . The cross-sectional shapes of the first shoring material, the second shoring material, the third shoring material, and the fourth shoring material are
8. The tunnel shoring according to claim 7 , which has a recess on one surface and a projection that fits in the recess on the other surface, and is formed in the same shape. The connecting member is
protruding from the recess of the first shoring material, the recess of the second shoring material, the projecting part of the third shoring material, and the projecting part of the fourth shoring material,
The first segment is
The connecting member provided on the first shoring material and the connecting member provided on the third shoring material are fixed and connected to each other,
The second segment is
The tunnel shoring according to claim 8 , wherein the tether member provided on the second shoring material and the tether member provided on the fourth shoring material are fixedly connected to each other. The connecting member is
10. The tunnel shoring according to claim 9 , wherein the distance between the first shoring material and the third shoring material and the distance between the second shoring material and the fourth shoring material are connected so as to be changeable. The connecting member is
11. The tunnel shoring according to claim 9 or 10 , wherein bolts passed through holes respectively formed in said connecting members are fastened with nuts and fixed to each other. The holes are
The tunnel shoring according to claim 11 , wherein a plurality of said connecting members are provided. Both ends of the arch portion are
The tunnel support according to any one of claims 7 to 12 , which is fixed to an inverted portion arranged along the bottom surface of the tunnel. The first shoring material, the second shoring material, the third shoring material, and the fourth shoring material,
Tunnel shoring according to any one of claims 7 to 13 , composed of angle steel.

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