JP2721645B2 - Underground structure and construction method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground structure and a method for constructing the underground structure, and more particularly to an underground structure for excavating a mountain surrounded by a tunnel to form an underground space and a method for constructing the underground structure.

[0002]

2. Description of the Related Art Generally, an urban tunnel has a higher construction cost than an above-ground structure, and its maintenance cost is often more uneconomical than an above-ground road. For this reason, underground roads are often constructed in unavoidable places, and the tunnel section is usually as short and as shallow as possible to shorten the approach portion.

[0003] When constructing an underground tunnel,
Generally, the excavation method is often adopted, but in recent construction, the number of cases where the excavation method cannot be adopted due to the roadside environment tends to increase.

[0004] When the open-cutting method cannot be adopted,
It is common practice to adopt a shield method.
In the current shield method, the circular cross section is the basic cross section,
At present, the maximum diameter reaches 14 m, and a large-diameter shield having a diameter of about 19 m is currently being planned.

[0005]

When the above-mentioned circular shield having a large diameter is employed, the cost of machine production becomes huge,
There was a problem that it was difficult to adapt to the construction environment in a large city, such as an increase in machine weight, an increase in segment weight, and the securing of shaft lands.

In the case of a shield having a large diameter, a large earth covering is required, and it is difficult to adopt this method when a tunnel having a relatively small earth covering is installed.

Further, it is difficult to cope with the case where the tunnel section is greatly expanded or reduced, or where it is desired to install a facility such as a branch or a junction in the basement, or where an emergency parking zone or the like is to be installed for each fixed section. There was a problem.

In addition, there is a problem that a shield machine becomes excessively large for a middle or short distance tunnel of about several hundred meters.

Therefore, a plurality of tunnels are excavated using a relatively small shield machine so as to surround a predetermined ground, and the ground surrounded by the tunnel is excavated to form an underground space. It is conceivable to address the aforementioned problems.

In this case, when connecting the tunnels,
The ground between tunnels must be excavated, which requires countermeasures against earth pressure and water stoppage, which requires enormous costs, requires many construction steps, and prolongs the construction period. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to reduce machine manufacturing costs, reduce machine weight and segment weight, and to secure land for shafts, etc. It can be easily adapted to the environment and requires little earth covering, and it can easily deal with the enlargement and reduction of the tunnel section, branching and merging, installation of various facilities, installation of emergency parking zones, etc. at regular intervals. The equipment including the shield machine does not become too large even for tunnels of middle distance and short distance of about 100 m, and while taking measures against earth pressure and water stoppage, the cost is low and the construction period is shortened. It is an object of the present invention to provide an underground structure that can be converted into an underground structure and a method for constructing the underground structure.

[0012]

In order to achieve the above object, an underground structure according to a first aspect of the present invention surrounds a predetermined ground by a plurality of tunnels formed by assembling segments in the ground. An underground structure that excavates the ground between surrounded tunnels to form an underground space, and structurally connects adjacent tunnel segments at predetermined intervals in the axial direction of the plurality of tunnels. A connection part,
A non-connection portion located between the connection portions of the plurality of tunnels,
It is characterized by having.

[0013] In the underground structure according to the second invention, the plurality of tunnels are formed adjacent to each other at a predetermined interval.
The connecting portion is characterized in that the ground between adjacent tunnels is excavated to structurally connect the segments.

According to a third aspect of the present invention, the plurality of tunnels are formed in a rectangular cross section.

A fourth aspect of the present invention is characterized in that part or all of the plurality of tunnels are used as various application spaces.

A fifth invention is characterized in that a part or all of the plurality of tunnels are filled with an amount of concrete according to design conditions.

In the sixth invention, a step of surrounding a predetermined ground with a plurality of tunnels formed by assembling segments along with shield excavation, and a predetermined interval in the axial direction of the plurality of tunnels In each case, a step of structurally connecting segments of adjacent tunnels, a step of excavating a ground surrounded by the plurality of tunnels to form an underground space, and a step of lining the inner wall of the underground space And is characterized by including.

[0018]

According to the first aspect of the present invention, there is provided a connecting portion which structurally connects adjacent tunnel segments at predetermined intervals, and a non-connecting portion located between the connecting portions. Accordingly, the external force acting on the non-connection portion can be supported by the connection portion, and the load can be transmitted from the connection portion to the foundation ground, so that the underground structure can be stably formed as a whole. In addition, in the unconnected part, the underground space can be formed without connecting the segments of each tunnel, the excavation of the ground for connection, the retaining, the construction process such as water stoppage, and This eliminates the need for facilities and equipment, thereby reducing costs and shortening the construction period.

In the second invention, a plurality of tunnels are formed at predetermined intervals, and in the underground connecting portion, the ground between segments of each tunnel is excavated to connect the segments. The shape and dimensions of the underground space can be easily changed without increasing the number of excavated tunnels, and the construction period can be shortened because the number of tunnels does not need to be increased.

In the third aspect of the present invention, an underground space having an arbitrary shape and dimensions can be formed by forming a tunnel having a rectangular cross section. Therefore, in the case of a tunnel for railways or roads, a circular cross section causes unnecessary cross sections at the upper and lower portions of the tunnel, but a rectangular cross section reduces unnecessary cross sections and increases the advantage of the cross section. It becomes possible.

Further, since the height of the tunnel is smaller than that of the circular shape, it is advantageous in terms of vertical alignment, and it is possible to reduce the earth covering.

According to the fourth aspect of the present invention, a part or all of the plurality of tunnels are formed as various application spaces, so that, for example, a ventilation path, an evacuation path, an inspection path, a drainage path, a wiring pipe path, and the like. It is possible to secure space.

According to the fifth aspect of the present invention, a part or all of the plurality of tunnels are filled with an amount of concrete in accordance with the design conditions, so that a design study corresponding to a load such as earth pressure or water pressure can be made. And the stability of the underground structure can be ensured.

According to the sixth aspect of the invention, adjacent tunnel segments are structurally connected to each other at predetermined intervals in the axial direction of the tunnel, and the ground surrounded by each tunnel is excavated. In parts other than the connection part, work requiring great cost and construction period such as earth retaining and water stoppage required for connection becomes unnecessary, and it is possible to greatly reduce the cost and shorten the construction period.

Further, since the connecting portion can be shortened, it is possible to suppress the cost and the construction period from being prolonged, even though the work such as excavation of the ground is performed.

Furthermore, by providing the inner wall with a lining, the underground space can be continuously formed in a ring shape in the axial direction to form a lining structure. can do.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 3 show an underground structure according to an embodiment of the present invention.

This underground structure 10 is used for a road tunnel, a railway tunnel, an underground parking lot, a power tunnel, a common ditch, or the like, and includes a plurality of tunnels formed by connecting segments 12 and 14 underground. 16, a predetermined ground is surrounded, and the ground between the surrounded tunnels 16 is excavated to form an underground space 18 shown in FIGS. 2 and 3.

Each of the tunnels 16 is excavated by using a rectangular shield excavator while the rectangular segment 1 is being excavated.
2 and 14 are assembled and connected to form a rectangular section, and the tunnels 16 having a plurality of rectangular sections form an underground space 18 having two adjacent rectangular sections as shown in FIGS. 2 and 3. ing.

Further, the adjacent tunnels 16 are excavated at predetermined intervals so that the size of the underground space 18 can be easily changed.

The underground structure 10 has a connecting portion 20
And the non-connecting portion 22.

The connecting portion 20 connects adjacent segments 12 for a predetermined distance L at predetermined intervals S in the axial direction of the plurality of tunnels 16, and fills the inside with concrete 24. It is formed as an annularly continuous state. In this way, by making the segments 12 continuous with each other by the concrete 24 in an annular shape, the connecting portion 20 has a sufficient structural strength.

When the adjacent segments 12 are connected to each other, since the segments 12 are separated from each other, the ground between the segments 12 of each tunnel 16 is excavated to connect the segments 12. I have.

More specifically, as shown in FIG. 4, the segment 12 forming the connecting portion 20 is
And a mountain plate 28.

The segment main body 26 has a substantially rectangular cross section, and has four plate-shaped segment pieces 30 and 32 on the ridge side and the connection side, and the four pieces disposed at the corners.
And two corner pieces 34.

The plate-shaped segment piece 30 on the dome side is
The main girder 36 and the joint plate 38 are framed in a rectangular shape, a skin plate 40 is attached to one side thereof, and a plurality of ribs 42 are provided between the main girder 36 to form a steel material.

The connection-side segment piece 32 includes a main girder 4
The steel plate 4 and the joint plate 46 are formed in a rectangular frame, and a plurality of channel-shaped mold steel members 48 are removably mounted between the main girders 44. The segment piece 32 on the connection side has the shape steel 48 attached only to the right side in FIG. 4, but when widening excavation is performed in both directions, the shape steel 48 is also mounted on the left side in FIG.
Is attached.

The corner piece 34 forms an L-shaped frame of the main girder 50 and the joint plate 52, and attaches an L-shaped skin plate 54 to the surface thereof, and a plurality of ribs 56 between the main girder 50.
It is made of steel material formed by attaching.

Then, the joint plate 52 of the corner piece 34
And the joint plate 3 of the adjacent segment pieces 30 and 32
The rectangular segment body 26 is formed by connecting the first and second segments 8 and 46 to each other.

As shown in FIGS. 6 and 7, the corner piece 34 on the right side in FIG. 4 where the widening excavation is performed is made of a steel material for supporting the retaining plate 28 at both ends of the skin plate 54. A support member insertion port 60 with a cover (not shown) for projecting the member 38 is formed, and the cover can be removed and the support member 58 can be inserted into the ground from the support member insertion port 60 when the tunnel is widened. I have to.

Further, the joint plate of the segment piece 30 and the joint plate 52 and the skin plate 54 of the corner piece 34 are provided with a stress member 64 such as a reinforcing bar or a PC steel bar for connecting the adjacent segment bodies 26 to each other. Through holes 62 to be inserted are formed at predetermined intervals. In addition, a lid (not shown) is attached to the through hole 62 formed in the skin plate 54 so that the stress material 64 can be inserted by removing the lid when widening the tunnel. Also,
The through hole 62 of the skin plate 54 can be used also as an injection hole for improving the ground at a tunnel connection portion.

The retaining plate 28 is slidably provided on the outer surface of the skin plate 40 of the segment piece 30 on the retaining side, protrudes from the segment body 26, covers the ground of the connecting portion, and performs the retaining of the connecting portion. It has become. A pair of long holes 66 extending in a direction orthogonal to the axial direction of the segment body 26 is formed in the skin plate 40 provided with the ridge plate 28, and a screw hole 68 facing the long hole 66 is formed in the ridge plate 28. Are formed at predetermined intervals, and in this long hole,
As shown in FIG. 5, a pair of hydraulic jacks 70 disposed inside the segment piece 30 are connected via a connecting member (not shown), and by operating the hydraulic jack 70, through a long hole 66. The retaining plate 28 is slid. In addition, a waterproof material such as a rubber ring is provided around the long hole 66.

As described above, by excavating the ground with the retaining plate 28, the excavation of the ground between the adjacent segments 12 can be performed easily and safely. In addition, since the retaining plate 28 is supported from the inside by the supporting member 58 protruding from the segment main body 26, a sufficient supporting force can be obtained. Further, the adjacent segments 12 are connected by the stress material 64 penetrated through the through-hole 62, the mold steel material 48 attached to the connection-side segment piece 32 is removed, and the ground exposed there is mini-backhoeed. Excavation is performed using an excavator such as that described above, and after the excavation is completed, the above-mentioned removed mold steel material 48 is secured between the main girder 44 constituting the segment piece 32 on the connection side of the adjacent segment 12 and fixed. A state is obtained, and a sufficient connection strength is obtained.

The non-connecting portions 22 are formed between the connecting portions 20 of the tunnels 16, and are connected to the connecting portions 2 of the tunnels 16.
The concrete 14 is filled in the segment 14 located between 0 and is formed. This unconnected part 2
2, the segment 14 of the adjacent tunnel 16
No excavation of the ground is performed, and the ground is left as it is. Therefore, the segment 14 constituting the non-connection portion 22 does not require the buckle plate 28, the stress member 64, and the mold steel member 48, and a normal rectangular segment that does not use them is used. I have.
In this manner, the non-connection portion 22 is connected to the adjacent segment 14.
The ground between them is left as it is without excavation, and the segments 14 are not connected to each other.
Itself is rigid, and the segment 1
Since the concrete 24 filled in the inside 4 has increased rigidity, the concrete 24 has sufficient strength.

When the connecting portion 20 and the non-connecting portion 22 are filled with the concrete 24, as shown in FIGS. 2 and 3, the tunnel 16 is located at a position where the earth pressure is so high. The tunnel 16 located at the boundary of the underground space 18 and the four tunnels 16 located at the bottom are made to be internal cavities and are made continuous in the axial direction, and these cavities are used as various application spaces, for example, an evacuation inspection path 72 and a drainage path 74.
And a ventilation path 76. It is not always necessary to use the whole of the segments 12 and 14 as a space in these various use spaces, and it is also possible to embed a pipe or the like in the concrete 24 to be filled and partially form the space.

Further, in this underground structure 10,
An inner lining 78 is applied to the side surface of the underground space 18 of the connecting portion 20 and the non-connecting portion 22 to perform a finishing process.

Here, assuming that the underground structure 10 having a height of 12 m, a width of 16 m and a dead weight of 7.5 t / m ² is constructed at a position of 5 m of overburden, the overburden load is 10 t / m.
m ² , side load is 7 t / m ^{2 at} the upper end and about 22 t / m 2 at the lower end
m ² .

In this case, assuming that the unit length of the estimated model of the underground structure is 13.5 m and the load of the non-connecting portion 22 is entirely covered by the connecting portion 20, the connecting portion 20 has its own weight of 101.25 t /. m, the overburden load is 135 t / m, the side load is 94.5 t / m at the upper end, and 297 t / m at the lower end. From this, the bending moment is obtained. Force N = -413t
Becomes

Therefore, the design sectional force is Md = 1634.
If t · m, N = −413t, the strength is sufficient.

Further, the sectional area of the stress material of the segment is determined by AS
= 1270.5 cm ² , for example, when the width of the connecting member is set to 350 cm and the height is set to 300 cm, and each stress is obtained by the RC allowable stress method, σ _c = 79 kgf / cm ₂ <80 kgf / cm ² (Allowable stress) σ _s = 1329 kgf / cm ₂ <1400 kgf / cm
² (Allowable stress) σ _s' = 958 kgf / cm ₂ <1400 kgf / cm ²
(Allowable stress), and a structural member having sufficient strength can be obtained.

Further, assuming that the cross-sectional area of the stress material of the segment in the longitudinal direction in the non-connection part 22 is AS = 2289 cm ² , for example, the length (span) of the non-connection part is 1000 cm,
RC with member width set to 300cm and member height set to 300cm
When each stress level is obtained by the allowable stress level method, σ _c = 9.5 kgf / cm ₂ <80 kgf / cm ² (permissible stress level) σ _s = 305 kgf / cm ₂ <1400 kgf / cm ²
(Allowable stress) σ _{s ′} = 119 kgf / cm ₂ <1400 kgf / cm ²
(Allowable stress), and a structural member having sufficient strength can be obtained. As described above, when the length of the connecting portion 20 is 3.5 m, the non-connecting portion 22 therebetween can be set to 10 m.

The above results were calculated on the premise that the tunnel was filled with concrete.

Further, depending on external force conditions, it is possible to take charge of external soil water pressure without filling concrete, and in this case, the inside of the segment can be used as an emergency passage or equipment space.

Next, a method of constructing an underground structure according to the above embodiment will be described.

First, with the excavation by the shield excavator, the segments 12 and 14 are connected to form a plurality of tunnels 1.
6 are formed, and the plurality of tunnels 16 surround a predetermined ground having a rectangular cross section. In this case, each of the tunnels 16 assembles and connects the segments 12 for a predetermined distance L at predetermined intervals S in the axial direction.
Within a predetermined interval S located between the two, the segments 14 are assembled and connected to form a tunnel 16. The tunnels 16 are formed adjacent to each other at a predetermined interval. In the tunnels 16 adjacent in the lateral direction, the segments 12 can protrude the retaining plate 28 in the lateral direction. The segments 12 of the tunnel 16 that are arranged and vertically adjacent to each other are arranged so that the buckle plate 28 can protrude vertically.

Next, the segments 12 of the adjacent tunnels 16 are connected at predetermined intervals S in the axial direction of the plurality of tunnels 16. In this case, as shown in FIG.
Since the ground 78 sandwiched between the segments 12 of the adjacent tunnel 16 may collapse when excavated depending on the soil quality, as shown in FIG. Perform ground improvement. In this case, the through-hole 62 formed in the skin plate 54 of the corner piece 34 constituting the segment body 12
The injection pipe 80 is inserted into the ground 78, and a ground improvement chemical is injected into the ground 78 to perform ground improvement.

Next, as shown in FIG. 11, the support member insertion opening 6 formed in the skin plate 54 of the corner piece 34 is formed.
Then, the support member 58 is inserted into the ground 78 through the support member insertion opening 60. In this case, when inserting the support member 58, a gantry is installed in the segment main body 12, a hydraulic jack is installed on the gantry, and the support member 58 is inserted into the ground 78 with the hydraulic jack. The distal end of the support member 58 is inserted up to a position corresponding to the surface of the skin plate 40 of the segment main body 12. Further, when the support member 58 is inserted, a water-stopping material is applied to the support member insertion port 60 so that water does not infiltrate into the segment main body 12 from between the support member insertion port 60 and the support member 58. I have to put.

Next, as shown in FIG. 12, the retaining plate 28 is press-fitted from the segment piece 30 of each segment 12 to the ground 78 whose ground has been improved by the hydraulic jack 70, and the tip of the retaining plate 28 The parts are polymerized. In this case, the retaining plate 28 slides and protrudes through the long hole 66 formed in the segment piece 30. Further, since the long hole 66 is stopped by the water blocking material, water does not enter the segment 12 from the long hole 66.

When the retaining plate 28 is pressed into the ground 78, the supporting member 58 protruding from the segment body 12 supports the retaining plate 28. The plate 28 is prevented from lowering forward, and the ridge plate 28 is securely supported so that ridges can be reliably formed. Further, when water is required to stop at the overlapped portion between the retaining plates 28, the skin plate 54
The through hole 62 is opened, and an injection pipe is inserted to inject a water-stopping agent to surely stop water. In addition, the ridge plate 28 does not necessarily need to protrude from each of the adjacent segments 12, and when the interval between the grounds 78 is narrow, it is possible to protrude from only one of the segments 12. In this case, Alternatively, the other segment may be a normal segment having no ridge plate 28.

Next, as shown in FIG.
The ground 78 between the segments 12 surrounded by is excavated. In this case, the mold steel material 48 attached to the connection-side segment piece 32 is removed, and the portion facing the ground 78 is opened. Then, the ground 78 between the segments 12 is widened and excavated from this open portion using an excavator such as a mini backhoe.

Next, with the ground 78 completely excavated, as shown in FIG.
The main girders 44 of the segment pieces 32 are connected to each other using the plurality of channel-shaped mold steel members 48 removed from the base member, and a stress material 64 such as a PC steel rod is inserted into the through hole 62 of the corner piece 34. Tightening applies an axial force to the stress member 64 to the extent of loosening. The widening excavation is also performed in the vertical direction.

Then, such a process is performed at a predetermined interval S
Each time, it is only necessary to perform the work for a fixed length L, and between the connecting portions 20, no ridge or widening excavation work is required, so that the construction period can be significantly reduced.

Then, concrete 24 is filled in the segments 12 connected at predetermined intervals and the segments 14 of the tunnels 16 between them at predetermined intervals, and the predetermined intervals S
The connecting portion 20 is formed at a portion of the segment 12 connected at a constant distance L every time, and the segments 14 between the connecting portions 20 are formed.
A non-connection part 22 is formed in the part. In such a state, the load of the non-connection portion 22 is transmitted to the connection portion 20, and by transmitting the load from the connection portion 20 to the ground at the bottom, sufficient strength can be provided.

Next, the ground surrounded by the connecting portion 20 and the non-connecting portion 22 is excavated to form an underground space 18 as shown in FIGS.

Then, if the inner lining 82 is applied to the side surface of the underground space 18 of the connecting portion 20 and the non-connecting portion 22 and the finishing process is performed, the underground structure 10 is completed.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, in the above-described embodiment, a case has been described in which a tunnel is formed by rectangular segments 12 and 14. However, the present invention is not limited to this example. For example, a tunnel can be formed by using circular segments. .

In the above embodiment, a description has been given of a state in which two rectangular underground spaces 18 are provided side by side. However, the present invention is not limited to this example, and various shapes of underground spaces can be formed.

[0070]

As described above, according to the first aspect of the present invention, adjacent tunnel segments are connected to each other at predetermined intervals, and concrete is filled therein to form a connecting portion. By filling concrete in the segment of each tunnel between and forming as a non-connected part, the load of the non-connected part can be transmitted to the connected part, and the load can be transmitted from this connected part to the ground at the bottom, Therefore, the underground space can be formed without connecting the segments of each tunnel in the non-connection part, and the construction process such as excavation of the ground for the connection, the staying, water stoppage, etc. There is no need for equipment, equipment, and the like, which has the effect of reducing costs and shortening the construction period.

Even in the case of the above structure,
Since the non-connection portion has a high strength in which concrete is filled therein, there is an effect that sufficient strength can be obtained.

According to the second aspect of the present invention, by forming a plurality of tunnels at predetermined intervals, the size of the underground space can be easily changed without increasing the number of excavated tunnels, and Since it is not necessary to increase the number of tunnels, there is an effect that the construction period can be shortened.

In the connecting portion, a continuous space in the connecting portion can be easily formed by excavating the ground between the segments of each tunnel and connecting the segments to each other. By filling concrete with concrete, there is an effect that even if there is an interval between tunnels, a strong annular connecting portion integrated with concrete can be formed.

According to the third aspect of the present invention, a rectangular underground space is formed by a plurality of rectangular tunnels formed by rectangular segments, so that a tunnel for a railway or a road has a circular cross section. Unnecessary cross sections occur at the top and bottom of the tunnel.
There is an effect that the advantage of the cross section can be increased.

Further, since the tunnel height is smaller than the circular shape, it is advantageous in terms of vertical alignment, and there is an effect that the earth covering can be reduced.

In the fourth invention, a part of the plurality of tunnels, for example, the inside of a tunnel located in the lower part of the underground space where large earth pressure is not applied is made hollow, and the connection part is also penetrated. By being formed in various axially continuous spaces in the axial direction, for example, there is an effect that spaces such as a ventilation path, an evacuation path, an inspection path, a drainage path, and a wiring pipe path can be secured.

According to the fifth aspect of the present invention, a part or all of the plurality of tunnels can be subjected to a design study according to a load such as an earth pressure and a water pressure according to a design condition, and an underground structure can be obtained. There is an effect that the safety of the body can be ensured.

According to the sixth aspect of the present invention, adjacent tunnel segments are structurally connected at predetermined intervals in the axial direction of the tunnel, and the ground surrounded by each tunnel is excavated. In the parts other than the connection part, there is no need for enormous cost and work requiring a construction period such as earth retaining and water stoppage required for connection, which has the effect of greatly reducing costs and shortening the construction period. is there.

Further, since the connecting portion can be shortened, there is an effect that the cost and the construction period are prevented from being prolonged in spite of the work such as excavation of the ground.

Further, by applying the internal lining, the underground space can be continuously formed in a ring shape in the axial direction to form a lining structure.
There is an effect that safety can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an underground structure according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a front view of a segment constituting a connecting portion.

FIG. 5 is a plan view showing a state where the segment piece on the ridge side in FIG. 4 is viewed from the inside.

FIG. 6 is a front view of the corner piece of FIG. 4 as viewed from the inside.

FIG. 7 is a sectional view taken along line VII-VII in FIG.

8 is a sectional view taken along the line VIII-VIII in FIG.

FIG. 9 is a cross-sectional view showing a state of adjacent segments in a connecting portion.

FIG. 10 is a cross-sectional view showing a state in which ground improvement of the ground at the connection portion has been performed from the state of FIG. 9;

11 is a cross-sectional view showing a state in which the support member of the retaining plate is inserted into the ground from each segment from the state of FIG.

FIG. 12 is a cross-sectional view showing a state in which the retaining plate is inserted into the ground from the state of FIG.

13 is a cross-sectional view showing a state where ground excavation between segments has been performed from the state shown in FIG. 12;

FIG. 14 is a cross-sectional view showing a state in which segments are connected to each other from the state shown in FIG. 13;

FIG. 15 is a cross-sectional view showing a state where concrete has been poured into the segment from the state of FIG. 14;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 underground structure 12,14 segment 16 tunnel 18 underground space 20 connecting part 22 non-connecting part 24 concrete 82 inner lining

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Tategawa 1-7-1 Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Inventor Makoto Okekagawa 1-7-1 Kyobashi, Chuo-ku, Tokyo (56) References JP-A-5-280296 (JP, A) JP-A-5-280297 (JP, A)

Claims (6)

(57) [Claims] An underground structure that surrounds a predetermined ground with a plurality of tunnels formed by assembling segments in the ground, and excavates the ground between the surrounded tunnels to form an underground space. At predetermined intervals in the axial direction of the plurality of tunnels,
An underground structure, comprising: a connection portion that structurally connects segments of adjacent tunnels; and a non-connection portion located between the connection portions of the plurality of tunnels. 2. The plurality of tunnels according to claim 1, wherein the plurality of tunnels are formed adjacent to each other at a predetermined interval, and at the connecting portion, a ground between adjacent tunnels is excavated to structurally connect the segments. An underground structure characterized by being connected. 3. The underground structure according to claim 1, wherein the plurality of tunnels have a rectangular cross section. 4. The underground structure according to claim 1, wherein a part or all of the plurality of tunnels are used as various use spaces. 5. The underground structure according to claim 1, wherein a part or all of the plurality of tunnels are filled with an amount of concrete according to design conditions. 6. A step of surrounding a predetermined ground with a plurality of tunnels formed by assembling segments according to shield excavation, and at predetermined intervals in an axial direction of the plurality of tunnels,
A step of structurally connecting segments of adjacent tunnels, a step of excavating a ground surrounded by the plurality of tunnels to form an underground space, and a step of lining the inner wall of the underground space. A method for constructing an underground structure, comprising: