JP3567401B2 - Large section tunnel and its construction method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a large-section tunnel suitable for use in constructing a rectangular tunnel having a large cross section and having a large cross section, and a method for constructing the tunnel.
[0002]
[Prior art]
As is well known, a shield construction method of excavating the ground with a shield excavator and constructing a tunnel having substantially the same diameter as the shield excavator behind the tunnel is often used for construction of a tunnel. However, in the shield method, if a tunnel with a large cross section is to be constructed, the shield excavator used for the tunnel will naturally become large, and as a result, manpower and costs will be reduced in all aspects of the production, transportation, on-site assembly, etc. of the shield excavator. It becomes bulky.
[0003]
For this reason, in recent years, a construction method of forming a large-sized tunnel structure from these small-diameter tunnels by constructing a large number of small-diameter tunnels along the shape of the large-section tunnel has been developed.
[0004]
By the way, especially when trying to construct a large-section tunnel having a large space inside, as shown in FIG. 7, a tunnel structure 1 having a circular section is constructed, and a space S having a predetermined dimension is formed inside the tunnel structure 1. In other words, since the tunnel structure 1 is large with respect to the space S, the land required for constructing the large-section tunnel T is required widely, increasing the cost. There is a problem that the space S cannot be formed.
[0005]
For this reason, as shown in FIG. 8, if a large-section tunnel T ′ having a rectangular cross section is constructed, a minimum necessary land for forming a space S having a predetermined dimension may be secured. In order to reduce the cost, various construction methods of such a large-section tunnel T 'having a rectangular section are developed.
[0006]
[Problems to be solved by the invention]
However, the conventional large-section tunnel and the method for constructing the same as described above have the following problems.
When constructing the tunnel structure 2 of the large-section tunnel T ′ having a rectangular cross section as shown in FIG. 8, the horizontal portion 2 a and the vertical portion 2 b that constitute the four sides of the tunnel structure 2 are each segmented in cross section. After being assembled in a square shape, it is necessary to connect the horizontal portion 2a and the vertical portion 2b adjacent to each other at the joint A.
For this, as shown in FIG. 9A, after separately constructing the horizontal portion 2a and the vertical portion 2b of the tunnel structure 2, first, the ground G1 between the horizontal portion 2a and the vertical portion 2b is removed. Ground improvement using chemical injection or freezing method. Subsequently, as shown in FIG. 9B, when constructing the horizontal portion 2a, the connecting portion retaining material 3 incorporated at the end thereof is extruded toward the vertical portion 2b. Then, after the connecting portion retaining material 3 reaches the vertical portion 2b, the segments 4 of the horizontal portion 2a and the vertical portion 2b are removed, and the connection bracket 5 is attached to the vertical portion 2b. After the horizontal portion 2a and the vertical portion 2b are integrally connected in this way, as shown in FIG. 9C, a reinforcing bar 6 and the like are arranged inside the concrete portion 7 and concrete 7 is cast therein, thereby forming a tunnel structure. Body 2 is completed.
[0007]
In such a construction method, first, the connection portion retaining material 3 is extruded. However, when the horizontal portion 2a is constructed, a back filling material such as mortar is injected into the outer periphery of the horizontal portion 2a. It is difficult to extrude the part retaining material 3.
In addition, in order to stop water and increase the strength of the seam portion A, the ground is improved by injecting a chemical solution or a freezing method. Needless to say, such ground improvement requires time and cost, and is complete. It is difficult to obtain a water stopping effect.
[0008]
Further, in a place where the width of the tunnel structure 2 changes or increases, the interval between the horizontal portion 2a and the vertical portion 2b becomes large, so that the area of the joint A where the ground needs to be improved greatly increases. However, this makes the problem even more pronounced.
[0009]
The present invention has been made in consideration of the above points, and aims to construct a large-section tunnel having a complete water stopping effect, while smoothly performing construction to shorten the construction period and reduce cost. It is an object of the present invention to provide a large-section tunnel and a construction method thereof.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a tunnel having a large cross section includes a tunnel structure having a substantially rectangular cross section and a tunnel space formed inside the tunnel structure. a rectangular rectangular shield tunnel, which is arranged adjacent to the alternating circular shield tunnel cross section circular, and the said rectangular shield tunnel and the circular shield tunnel adjacent to each other, and integrated by polymerizing together a part A tunnel having a large cross section , wherein a length of a side in a cross-sectional direction of the tunnel structure is gradually increased or decreased along an axial direction of the tunnel structure, and is located on both sides of the circular shield tunnel. rectangular shield tunnel each other are gradually separated from or approach, and said circular shield tunnel and the rectangular shield tunnel adjacent to each other Is characterized in that polymerization dimensions are gradually decreased or increased.
[0011]
According to a second aspect of the present invention, in the large-section tunnel according to the first aspect, as the overlapping dimension of the rectangular shield tunnel and the circular shield tunnel gradually decreases or increases, a segment of the rectangular shield tunnel is formed. It is characterized by a gradual increase or decrease in dimensions.
[0012]
The invention according to claim 3 is that after a plurality of rectangular shield tunnels are pre-constructed at predetermined intervals, a circular shield tunnel is partially placed on the ground between the rectangular shield tunnels adjacent to each other. By superimposing the shield tunnel on the subsequent construction, a tunnel structure in which the rectangular shield tunnel and the circular shield tunnel are alternately arranged adjacent to each other is constructed, and thereafter, a ground inside the tunnel structure is formed. A method of constructing a tunnel having a large cross section by excavating a mountain and forming a space therein, wherein a portion where the length of a side of the tunnel structure gradually increases or decreases along its axial direction is used. The rectangular shield tunnels adjacent to each other are constructed so as to gradually separate or approach each other. When building a panel it is characterized progressively reducing or increasing the polymerization dimensions of these rectangular shield tunnel and circular shield tunnel.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of an embodiment of a large-section tunnel and a method of constructing the tunnel according to the present invention will be described with reference to FIGS.
[0014]
As shown in FIG. 1, a large-section tunnel 10 to be constructed is used, for example, as a highway provided underground. The large-section tunnel 10 is provided with a merging ramp L for joining a branch line 10B to a main line 10A. Have been.
As is well known, the merging ramp L is provided with an acceleration lane X for accelerating the vehicle traveling from the branch line 10B. A tapered portion D whose width gradually changes toward the main line 10A is formed.
[0015]
FIG. 2 shows, for example, a main line 10A of a large-section tunnel 10, in which a tunnel structure 11 which is a lining body for resisting earth pressure from the surrounding ground and a tunnel structure 11 are shown. It comprises two upper and lower internal spaces 12A and 12B formed inside the body 11.
[0016]
The tunnel structure 11 includes side walls 11a, 11a on both sides positioned substantially in a vertical plane, and upper and lower surfaces 11b, 11b provided between upper and lower ends of the side walls 11a, 11a and positioned substantially in a horizontal plane. 11c, and a partition surface 11d provided between the middle portions of the side wall portions 11a, 11a to partition the upper and lower internal spaces 12A, 12B, and has a substantially Japanese character in cross section as a whole.
[0017]
This tunnel structure 11 has a configuration in which a circular shield tunnel 15 having a circular cross section and a flat shield tunnel (rectangular shield tunnel) 16 having planes parallel to each other are alternately arranged in the circumferential direction, and these are integrated. Consists of
[0018]
The diameter of the circular shield tunnel 15 is larger than the thickness of the flat shield tunnel 16. Further, the circular shield tunnel 15A arranged at the four corners of the tunnel structure 11 and the portion where the plane shield tunnel 16 is joined on three sides has a larger diameter dimension than the shield tunnel 15B of the other portion. Things have been adopted. In addition, the upper surface 11b and the lower surface 11c of the tunnel structure 11 are each configured to have a convex shape with the circular shield tunnel 15B as the apex.
[0019]
In such a tunnel structure 11, a reinforcing bar 18 is arranged around the entire circumference thereof, and concrete 19 is cast and filled.
[0020]
Then, in the tapered portion D (see FIG. 1) whose width gradually increases from the main line 10A having the above configuration toward the acceleration lane X, as shown in FIG. 3, the planar shields located on both sides of the circular shield tunnel 15B. The interval between the tunnels 16 is gradually increased. Furthermore, with the increase in the distance between the plane shield tunnels 16, 16, the circular shield tunnels 15 A, 15 A located on both sides thereof and the plane shield tunnels 16, 16 forming the side walls 11 a, 11 a of the tunnel structure 11. Are also constructed so that the interval gradually increases.
[0021]
Next, a method of constructing such a large-section tunnel 10 will be described. Here, the case where the large-section tunnel 10 is constructed from the main line 10A toward the tapered portion D will be described.
In order to construct the main line 10A of the large-section tunnel 10 shown in FIG. 2, first, rectangular shield tunnels 20, 20,... Are formed to form plane shield tunnels 16, 16,. Build ahead. As shown in FIG. 4, to construct each rectangular shield tunnel 20, a rectangular hole 22 is drilled in the ground by a shield excavator (not shown) having a rectangular cross section, and segments 23, 23 are provided behind the rectangular hole 22. ,… Are assembled.
[0022]
The two opposing surfaces of each segment 23 are flat plate portions 23a, 23a, and both sides of these flat plate portions 23a are substantially arc-shaped concave portions 23b, 23c. Each of the recesses 23b and 23c is formed such that the radius of curvature of the arc is slightly larger than the diameter of the circular shield tunnel 15 (see FIG. 2) constructed on the side.
After assembling such a segment 23, a back filling material 25 such as concrete, mortar, fiber concrete or the like is filled between the excavated hole 22 and the outer peripheral surface of the segment 23. Thereby, a rectangular shield tunnel 20 having a rectangular cross section is constructed in each hole 22.
[0023]
Next, circular holes 26, 26,... Are drilled in the ground between adjacent rectangular shield tunnels 20, 20 by using a shield excavator (not shown) having a circular cross section. The shield excavator (not shown) used here has a diameter substantially the same as that of the circular shield tunnels 15A and 15B to be constructed here. At this time, along with the ground between the rectangular shield tunnels 20, 20, the back filling material 25, 25 outside the concave portions 23b, 23c of the segments 23, 23 is also cut at the same time.
[0024]
As shown in FIG. 5, the circular segments 27, 27,... Are assembled behind the shield excavator (not shown) while each hole 26 is excavated in this way. Then, the outside of the assembled segment 27 is filled with a backing filler 28 such as concrete, mortar, fiber concrete, or the like, so that circular shield tunnels 15A and 15B are constructed in the respective holes 26.
As a result, the circular shield tunnel 15 having a circular cross section and the plane shield tunnel 16 are alternately arranged in the circumferential direction, and the circular shield tunnels 15A and 15B and the plane shield tunnel 16 are partially overlapped. The structure 11 is formed.
[0025]
Subsequently, as shown in FIG. 2, reinforcing bars 18 are arranged in the tunnel structure 11, and concrete 19 is poured and filled. Thereafter, the ground inside the tunnel structure 11 is excavated, and the internal spaces 12A and 12B are formed therein, whereby the main line 10A of the large-section tunnel 10 having a predetermined shape is constructed.
[0026]
To construct a tapered portion D (see FIG. 1) whose width gradually increases from the main line 10A toward the acceleration lane X, first, like the main line 10A, as shown in FIG. In order to form 20, 20, rectangular holes 22, 22 are drilled with a rectangular shield excavator.
At this time, in the tapered portion D, in the portion where the upper surface 11b, the lower surface 11c, and the partition surface 11d of the tunnel structure 11 are formed, the interval between the rectangular holes 22, 22 gradually increases as going forward in the excavation direction. .
The segment 23 is assembled behind the hole 22 while drilling each hole 22 in this manner. At this time, the concave portion 23b on the circular shield tunnel 15B side is positioned so that the position with respect to the center axis of the circular shield tunnel 15B is constant. I do. On the other hand, the concave portion 23c on the circular shield tunnel 15A side is gradually separated from the center axis of the circular shield tunnel 15B according to the displacement of the hole 22. Thus, the width of the segment 23 gradually increases as it goes forward in the digging direction.
After assembling the segment 23 of the tapered portion D in this manner, the back filling material 25 is filled between the excavated hole 22 and the outer peripheral surface of the segment 23. At this time, on the side of the circular shield tunnel 15B, the thickness of the back filling material 25 becomes gradually thinner as it goes forward in the digging direction.
[0027]
Next, circular holes 26, 26,... Are drilled in the ground between adjacent rectangular shield tunnels 20, 20 by using a shield excavator (not shown) having a circular cross section. At this time, the hole 26 for forming the circular shield tunnel 15 </ b> B is formed in a straight line without being displaced in the cross-sectional direction with respect to the central axis of the tunnel structure 11. On the other hand, the hole 26 for forming the circular shield tunnel 15A is drilled so as to be gradually separated from the circular shield tunnel 15B in accordance with the displacement of the rectangular shield tunnel 20.
When the holes 26 are drilled in this manner, the backfill fillers 25, 25 outside the recesses 23b, 23c of the segments 23, 23 as well as the ground between the rectangular shield tunnels 20, 20 are simultaneously drilled.
[0028]
Thereafter, as shown in FIG. 3, circular segments (segments) 27, 27,... Are assembled behind a shield excavator (not shown). Then, by filling the outside of the assembled segment 27 with the back filling material 28, the circular shield tunnels 15A and 15B are constructed in the respective holes 26.
That is, as the distance between the plane shield tunnels 16 and 16 increases, the overlapping dimension between the circular shield tunnel 15B located therebetween and each plane shield tunnel 16 gradually decreases.
[0029]
After constructing the circular shield tunnel 15 and the plane shield tunnel 16 in this way, reinforcing bars 18 are arranged in the tunnel structure 11, and concrete 19 is poured and filled. Thereafter, the ground inside the tunnel structure 11 is excavated and the internal spaces 12A and 12B are formed therein, thereby completing the construction of the tapered portion D of the large-section tunnel 10 having a predetermined shape.
[0030]
In the above-described large-section tunnel 10 and the method of constructing the same, in the tapered portion D where the width of the tunnel structure 11 constituting the large-section tunnel 10 gradually increases, the preceding construction is performed such that the rectangular shield tunnels 20 adjacent to each other are gradually separated from each other. Then, the overlapping dimension with the circular shield tunnel 15B to be subsequently constructed is gradually reduced to construct the tunnel structure 11. This makes it possible to construct the tapered portion D of the large-section tunnel 10 without improving the ground by injecting a chemical solution or the like as in the conventional case. Therefore, it is possible to suppress the cost required for the conventional ground improvement and shorten the construction period. Furthermore, since a higher water stopping effect can be obtained as compared with the ground improvement method, the safety of the construction of the large-section tunnel 10 can be greatly improved.
[0031]
In the above-described embodiment, the large-section tunnel according to the present invention and the method of constructing the same are applied to the tapered portion D having a gradually increasing width. it can. Furthermore, the present invention can be similarly applied to a case where the height, not the width, of the large-section tunnel 10 increases or decreases.
[0032]
【The invention's effect】
As described above, according to the large section tunnel according to claim 1, a tunnel structure, a rectangular shield tunnel and a circular shield tunnel, there is adjacent alternately arranged by polymerizing a part, in the portion for gradually increasing or decreasing the length of a side in the cross-sectional direction of the tunnel structure, a rectangular shield tunnel and a circular shield tunnel gradually away or approach a rectangular shield tunnel each other, located on opposite sides of the circular shield tunnel and adjacent to each other And the size of the overlapped polymer gradually decreases or increases . Further, according to the large section tunnel according to claim 2, with the polymerization dimensions of a rectangular shield tunnel and a circular shield tunnel is gradually increased or decreased, gradually decrease or increase the size of the segments constituting the rectangular shield tunnel . This makes it possible to perform the construction in a section where the width and height of the tunnel structure gradually increases and decreases without improving the ground by injecting a chemical solution or the like as in the related art. Therefore, it is possible to reduce the cost and shorten the construction period which were conventionally required for ground improvement, and furthermore, it is possible to obtain a higher water stopping effect as compared with the ground improvement method. Safety can be greatly improved.
[0033]
According to the method for constructing a large-section tunnel according to claim 3, after a plurality of rectangular shield tunnels are pre-constructed at predetermined intervals, a circular shield tunnel is partially formed between the rectangular shield tunnels adjacent to each other. the by forming a space drilled inward natural ground of building a tunnel structure by building trailing by polymerizing these rectangular shield tunnel, then the tunnel structure, a method of constructing a large sectional tunnel In the portion where the length of the side of the tunnel structure is gradually increased or decreased, a rectangular shield tunnel is constructed in advance so that the rectangular shield tunnels are gradually separated or approached, and a circular shield tunnel is constructed to follow the rectangular shield tunnel. And the polymerization size is gradually reduced or increased. As a result, construction can be performed in sections where the width and height of the tunnel structure gradually increases and decreases without improving the ground by injecting chemicals as in the past, reducing cost and construction time, and improving construction safety. It can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a plan sectional view showing an example of a large-section tunnel according to the present invention and a tunnel to which a method for constructing the tunnel is applied.
FIG. 2 is an elevational sectional view showing a normal portion of the tunnel.
FIG. 3 is an elevational sectional view showing a widened portion of the tunnel.
FIG. 4 is a sectional elevational view showing a state in the middle of construction of the portion shown in FIG. 2;
FIG. 5 is an elevational sectional view showing a state following FIG. 4;
6 is an elevational sectional view showing a state in the middle of construction of the portion shown in FIG. 3;
FIG. 7 is a vertical sectional view showing an example of a conventional large-section tunnel.
FIG. 8 is an elevational sectional view showing an example of a conventional large-section tunnel having a rectangular shape in a sectional view.
9 is a process chart showing a method for constructing the large-section tunnel shown in FIG. 11;
[Explanation of symbols]
10 Large section tunnel 11 Tunnel structure 12A, 12B Internal space (tunnel space)
15 circular shield tunnel 16 plane shield tunnel (rectangular shield tunnel)
20 rectangular shield tunnel 23 segments

Claims (3)

A tunnel having a large cross section is composed of a tunnel structure formed in a substantially rectangular cross section and a tunnel space formed inside the tunnel structure,
The tunnel structure, a rectangular shield tunnel having a rectangular cross section and a circular shield tunnel having a circular cross section are alternately arranged adjacent to each other, and the rectangular shield tunnel and the circular shield tunnel adjacent to each other are partially formed. It is a large section tunnel that is integrated by polymerizing each other,
In the portion where the length of the side in the cross-sectional direction of the tunnel structure gradually increases or decreases along the axial direction of the tunnel structure, the rectangular shield tunnels located on both sides of the circular shield tunnel gradually separate or approach each other. large cross-section tunnels, and and characterized in that it polymerized dimensions gradually decrease or increase of the rectangular shield tunnel and the circular shield tunnel adjacent to each other. 2. The large-section tunnel according to claim 1, wherein a dimension of a segment forming the rectangular shield tunnel gradually increases or decreases as an overlapping dimension of the rectangular shield tunnel and the circular shield tunnel gradually decreases or increases. A large section tunnel characterized by: After a plurality of rectangular shield tunnels are pre-constructed at predetermined intervals, a circular shield tunnel is formed by overlapping a part of the ground between the rectangular shield tunnels adjacent to each other with these rectangular shield tunnels. By constructing, a tunnel structure in which the rectangular shield tunnel and the circular shield tunnel are alternately arranged adjacent to each other is constructed, and after that, the ground inside the tunnel structure is excavated to form a space here. a method for constructing a tunnel having a large cross-section by forming,
In the portion where the length of the side of the tunnel structure is gradually increased or decreased along the axial direction, the rectangular shield tunnels adjacent to each other are constructed so as to gradually separate or approach each other, and thereafter the circular shield tunnel is formed. A method of constructing a large-section tunnel, characterized in that, when constructing a tunnel, the overlapping dimension of the rectangular shield tunnel and the circular shield tunnel is gradually reduced or increased.

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