JP2977985B2 - Underground space construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground space suitable for use in constructing a highway or the like underground in an urban area.

[0002]

2. Description of the Related Art Conventionally, when an underground space for use on a highway or the like is to be formed underground in an urban area, it is necessary to excavate soft ground under an existing road in a stable manner. Excavated by shield method. Therefore, since the excavated cross-sectional shape of such underground space is restricted by the shield device, it is difficult to form a large cross section, and the underground space is excavated with a circular or nearly circular cross-sectional shape of the shield device.

[0003]

However, in the digging space excavated in such a cross-section having a circular shape or a shape close to a circular shape, the inside actually used is often a box-shaped space inside the digging space. It is unavoidable that a useless space is created between the excavated section and the service section. For this reason, when trying to obtain a large box-shaped space, such wasted space is correspondingly increased, which is against the efficiency of land use, and this is especially true in underground urban areas. As described above, when the excavation area is very limited, it is not preferable.
In view of the above circumstances, the present invention provides an underground space construction method that stably constructs a large cross-section box-shaped space without forming a useless space in the excavation space and improves land use efficiency. To provide.

[0004]

That is, according to the present invention, when an underground space (30) having a substantially rectangular cross section is constructed in the ground (2), the underground space (3) corresponding to the corner of the cross section of the underground space (3) is formed. Advanced pits (5) and (6) are excavated and formed in the direction of underground space excavation, respectively.
(6) The structural member (10) is installed in the ground (2) so as to connect between the advanced pits (5), (5) or (6), (6) adjacent to each other in the left-right direction, and a cross section is provided. Substantially square structure (7)
And the ground (2) is removed by removing the ground (2) inside the structure (7) constructed in a substantially square cross section.
It is configured such that a service space (30) is formed therein. In addition, the structural member (10) includes the advanced shaft (5),
It comprises a plurality of pillars (110) arranged along the excavation direction of (6), and the pillars (110) connect the unit pillars (11) to the ground (2) between the advanced shafts (5) and (6). In some cases, it is constructed by connecting and arranging a plurality of series in a form propelling the inside, and introducing prestress between the unit pillars (11) arranged in a plurality of series to integrate them into a column shape. . Further, the structural member (10) is composed of a plurality of pillars (110) arranged along the excavation direction of the advanced shafts (5) and (6), and
0) is the unit column material (11) and the advanced well (5), (6)
The structural material installation space (11a) is formed in a columnar shape by connecting and arranging a plurality of serially connected unit pillars (11) so as to be propelled in the ground (2) between them. And
In the structural material installation space (11a), the structural materials (13), (1)
In some cases, a plurality of unit column members (11) may be connected and integrated in a column shape by installing 5).
The numbers and the like in parentheses are for convenience showing the corresponding elements in the drawings, and therefore, the description is not limited to the description on the drawings. below

The same applies to the column of [Action].

[0005]

According to the construction described above, the present invention provides a service space (3
Prior to formation of 0), the structure (7) is
Acts as if built in. Also, when constructing the structure (7), the unit pillars (11) are propelled one by one into the ground (2) one by one from the advanced pits (5) and (6) so that they are connected. May work. Further, the structural members (13) and (15) may act to reinforce the column member (110).

[0006]

1 is a cross-sectional view showing an example of an underground space constructed according to the present invention, FIG. 2 is a plan view taken along the line II-II of FIG. 1, and FIG. FIG. 4 is a cross-sectional side view showing an example, FIG. 4 is a perspective view showing an example of a precast pillar row wall portion in the underground space shown in FIG. 1, and FIG. 5 shows another example of a precast pillar row wall portion in the underground space shown in FIG. FIG.

As shown in FIG. 1, the underground structure 1 has an excavation space 3 excavated in a box shape with four corners enlarged in a ground 2 made of, for example, cohesive soil, soft rock, or the like. Is the public-private boundary line 2 set as shown by the dotted line in the figure of the ground 2.
1 and 21 are arranged so as to extend in a direction orthogonal to the paper surface of FIG. The excavation space 3 is now being constructed from the near side to the back side of the paper in FIG.
Behind the middle sheet, the face 3a and the advanced face 5a shown in FIG.
6a is arranged. The upper part of the excavation space 3 in FIG.
That is, for example, a public road in service is already provided on the ground 2a between the public-private boundaries 21 and 21, and a portion of the ground 2 other than between the public-private boundaries 21 and 21 is provided with, for example, a private structure on the ground 2a. Due to the existing ground, the use of this part of the ground 2 is not allowed. Said 4 of the excavation space 3
The corner enlarged portion is formed by a NATM cavity 5 and a shield cavity 6 described below. That is, FIG.
On the left and right of the upper middle part, NATM cavities 5 and 5 are provided extending in a direction orthogonal to the paper surface of FIG. The shape is maintained in a form supported by a primary lining such as a lock bolt. On the other hand, shield cavities 6, 6 are provided on the left and right of the lower part of the excavation space 3 in FIG. 1 so as to extend in a direction perpendicular to the plane of the paper of FIG. The shape of the cavity 6 is maintained by being supported by a known segment. FIG.
In the NATM cavity 5 and the shield cavity 6 on the near side of the inner surface of the paper, the portion shown by the dashed line in FIG. 1 has already been removed and replaced with a structure 7 and a service space 30 to be described later. .

On the other hand, a structure 7 is provided in the excavation space 3 in the form of a rectangular tube extending in a direction perpendicular to the plane of the paper of FIG. Of 4
The NATM cavity 5 or the shield cavity 6 shown
1 and a precast column wall 10 that connects the concrete frames 9, 9 vertically or horizontally in FIG. The precast column row wall 10 is, for example, a pile 1 configured by connecting a plurality of RC concrete pipes 11 formed to a predetermined length L1 in series in the vertical direction or the horizontal direction in FIG.
2 are formed in parallel with each other along the excavation direction of the excavation space 3 indicated by arrows A and B in FIG. 2 (in a direction perpendicular to the plane of FIG. 1), as shown in FIG. Inside each of the RC concrete pipes 11 connected in series, a tensioning PC steel material (not shown) for connecting the plurality of RC concrete pipes 11 in series and integrating them as a pile 110 is connected in series. It is disposed so as to penetrate the connected RC concrete pipe 11. Structure 7
Is still under construction together with the excavation space 3 which is already under construction, so that the structure 7 is located only in the ground 2 on the right side as shown in FIG. Have been constructed and arranged. In addition, only the NATM cavity 5 and the shield cavity 6 are formed at the left end portion of the ground 2 shown in the direction of arrow A in FIG.
However, it has not yet been formed into the four-corner enlarged box shape shown in FIG. In the structure 7, a near-box (right side in FIG. 3) portion of the paper in FIG. 1 is provided in a substantially box-shaped service space by excavating and removing the ground 2 in the structure 7. 3
0 is provided so as to be surrounded by the four precast column walls 10 and the concrete skeleton 9 at the top, bottom, left, and right in FIG. 1, and the back side portion of the structure 7 in FIG. Since the ground 2 in the structural body 7 has not been excavated and removed yet, the service space 30 has not been formed in the left side portion). An intermediate floor plate 12 made of a precast concrete plate is provided at a central portion in the vertical direction of the structure 7.
However, in FIG. 1, the middle floor plate 12 is fixedly connected to the left and right precast column walls 10, 10 extending vertically in FIG. 1. Supported. In the embodiment, FIG.
The minimum overburden thickness of the excavation space 3 indicated by the middle arrow D1 is 5.000 m
m, the cross-sectional diameter of NATM cavity 5 and shield cavity 6 is 4.
000 mm, the outer diameter of the RC concrete pipe 11 is φ1300 mm, and the assumed groundwater level of the ground 2 is set as indicated by an arrow WL in FIG. 1. The transverse width (length in the left-right direction in FIG. 1) is 10.500 mm.

Since the underground structure 1 has the above configuration, the underground structure 1 can be constructed by starting excavation from a shaft or the like appropriately formed on the ground 2 by using the public-private boundary line 21.
Between 21, NATM cavities 5 and 5 and shield cavities 6 and 6 are excavated and formed, and a structure 7 is constructed in the ground 2 using the four cavities 5, 5, 6 and 6. Ground 2 in structure 7
Is removed, and a box-shaped service space 30 is formed. Therefore, first, a via hole 3b is provided at a portion (not shown) on the side of the arrow B in FIG. 3 through the shaft, and the NATM cavity 5 and the shield cavity 6 are respectively vertically arranged from the via hole 3b.
The NATM cavities 5 are excavated to have a gate-shaped cross section and the shield cavities 6 are excavated to have a circular cross section in such a manner that the holes are simultaneously excavated. Then, for example, in the NATM cavity 5, the primary lining is performed after excavation, and in the shield cavity 6, segments are erected while the shield device is propelled to maintain the shapes of these cavities 5, 6. Now, these cavities 5 and 6 are advanced as working pits of the excavation space 3 to be formed later, and these four cavities are located at the end in the arrow A direction shown at the left end in FIG. The advanced face 5a, 6a of each of the cavities 5, 6 is arranged.

After the NATM cavity 5 and the shield cavity 6 have been formed in this way, the RC concrete pipe 11 is fitted and supported by using the cavities 5 and 6 to a casing or the like having a bit mounted at the tip thereof. 1. From one cavity 5 (or 6) facing the middle in the vertical or horizontal direction to the other cavity 5 (or 6), the ground 2 extends in a direction orthogonal to the excavation direction indicated by arrows A and B in FIG. Promote inside. Then, a plurality of RC concrete pipes 11 are arranged in series so as to be sequentially connected to the rear of the RC concrete pipe 11 propelled into the ground 2 to form a pile 110. For example, in the embodiment, seven RC concrete pipes 11 are connected in series between the upper and lower portions of the cavities 5 and 6 in FIG. 1, and the left and right portions of the cavities 5 and 6 and the cavities 6 and 6 in FIG. Has four RC concrete pipes 11 connected in series,
Each pile 110 is formed. Then, in such a manner that the piles 110 thus formed are arranged side by side along the excavation direction without any gap, the precast column row walls 10 are sequentially extended from the side of the wellhead 3b in the direction of arrow B in FIG. Go. The piles 110 adjacent in the directions of the arrows A and B are firmly fastened by a known joining method. Then, since the upper, lower, left, and right walls of the service space 30 to be formed later are formed, the precast column row walls 10 forming the upper, lower, left, and right walls are given strength enough to withstand the earth pressure of the ground 2. Then, for example, one end side is fixed with a wedge, a screw, or the like via a PC steel material (not shown) which is previously arranged in the RC concrete pipe 11 of each pile 110 or newly arranged. A pre-stress is applied to each pile 110 by a predetermined tension while being tensioned from the other end side. In this way, since the precast column walls 10 formed by arranging the RC concrete pipes 11 in series and in parallel may be capable of supporting the earth pressure of the ground 2 in a state where the prestress is introduced into each pile 110. The diameter of each RC concrete pipe 11 can be small, and therefore, the work of propelling and connecting the RC concrete pipes 11 can be easily performed. Further, since the NATM cavity 5 and the shield cavity 6 are formed in the ground 2 into which the RC concrete pipes 11 are pushed in along the digging directions indicated by arrows A and B, each RC concrete tube 11 is formed. When arranging the pipes 11, it suffices to simply make the propulsion series in a direction orthogonal to the excavation direction. Therefore, the precast column wall 10 can be accurately extended without bending the service space 30 formed later. Can be and now,
The advancing tip 10a of the precast column row wall 10 is disposed at the center in the directions of arrows A and B shown in FIG.

In this way, prestress is introduced into each of the piles 110, and when the precast column rows 10 forming the upper, lower, left and right walls of the service space 30 formed later extend by a predetermined traveling pitch, respectively, In order to connect and integrate the precast column walls 10 into a structure 7, a reinforcing bar and a formwork are assembled in the NATM cavity 5 or the shield cavity 6 which is the propulsion start or end of each RC concrete pipe 11, and the site is constructed here. The concrete is cast to form the concrete frame 9. Then, four corners of the structure 7 are formed by the four concrete skeletons 9 in FIG. 1, whereby the upper, lower, left, and right precast column walls 10 in FIG. 1 are connected and integrated into a rectangular cylindrical shape. . Thus, ground 2
When the structure 7 is constructed in the shape of a rectangular tube so as to connect the NATM cavity 5 and the shield cavity 6, the earth and sand of the ground 2 is still arranged inside the structure 7. Therefore, the structure 7
Has been extended in the direction of arrow A in FIG. 3 by a predetermined traveling pitch, and then the service space 30 is formed by excavating and removing the ground 2 in the structure 7 as shown on the right side in FIG. Here, the structure 7 is already in a state where the ground 2 around the structure 7 is already supported by the precast column walls 10 in which the prestress has been introduced into the respective piles 110. The earth and sand on the ground 2
Excavation and removal by any arbitrary means such as a power shovel or other known boring machine as shown in FIG.
The excavation operation can be performed safely without fear of the structure 7 collapsing. Therefore, even if a large cavity is formed in the ground 2 by removing the ground 2 in the structure 7 in this manner, the above-mentioned public roads on the ground 2a between the public-private boundary lines 21 are affected. There is no concern. When the service space 30 is formed by excavating and removing the soil from the ground 2 in the structure 7 in this manner, the service space 30 is formed in a box-like shape in which the upper, lower, left, and right walls are formed by the rectangular tubular structure 7. Take shape. Then, the box-shaped service space 30 is extended from the direction of arrow B shown in FIG. The service space 30 has the NATM cavities 5 and 5 and the shield cavities 6 and 6 as four corners, and the public-private boundary lines 21 and 21 are formed.
It is possible to have a large space section full of the area in between,
Therefore, the ground 2 between the public-private boundary lines 21 is utilized very efficiently. When the service space 30 is formed in this manner, the intermediate floor plate 12 may be disposed by, for example, connecting a precast concrete plate or the like to the side wall portion of the precast column wall 10 by a reinforcing bar, or may be necessary for the other service space 30. The base material 1 is completed by appropriately fixing the interior material and the like to the structure 7 as necessary.

By the way, the service space 3 in the ground 2
0 is formed, the ground 2 has NAT as described above.
The M cavities 5 and 5 and the shield cavities 6 and 6 are excavated in advance, and the ground 2 in the structure 7 is further excavated and removed therefrom. 3 has a box shape with four corners enlarged as shown in FIG. Therefore, there is a structure 7 between the actually excavated excavation space 3 and the service space 30, and the NATM cavity 5 and the shield cavity 6 are arranged outside the four corners of the structure 7. There are only a few voids in the shape. The NATM
The voids outside the structure 7 in the cavity 5 and the shield cavity 6 need only have a very small space for working when the concrete body 9 of the structure 7 is cast on site and for other work. Therefore, almost all of the excavation space 3 can be used without any waste as the box-shaped service space 30, and there is no waste in the construction such as excavation and construction for forming the service space 30.

Further, in the above-described embodiment, each of the plurality of piles 110 constituting the precast column wall 10 is formed by connecting a plurality of RC concrete pipes 11 in series and connecting them to a PC steel wire for tension. An example is described in which a prestress is introduced through the like and integrated into a columnar shape, but a plurality of serially connected piles 110 are formed inside the pile 110 thus formed as shown in FIG. A void 11a is formed in a column shape so that each RC concrete pipe 11 passes through. Therefore, as shown in FIG. 4, concrete 13 may be placed in a column shape in each of the voids 11 a together with a reinforcing reinforcing bar 15 such as a known connecting reinforcing bar. As a result, the strength of the precast column walls 10 can be selectively increased in a form in which the piles 110 are reinforced by structural materials such as the reinforcing steel bars 15 and the concrete 13, so that when the earth pressure of the ground 2 is large, In addition, the strength of the precast column wall 10 can be designed so as to sufficiently support it, and the stability of the structure 7 can be further enhanced. The reinforcing reinforcing bar 15 is not limited to a known connecting reinforcing bar or the like, but may be appropriately replaced with a reinforcing member such as a reinforcing bar basket or a mesh, a bar reinforced with a fiber such as a resin, or another reinforcing member. No problem. Further, even if only the concrete 13 is cast and filled in the gap 11a as so-called unreinforced concrete, the pile 110 is reinforced, so that the pile 11 may be used. Similarly, as described above, the concrete 13 is not cast in the gap 11a. A suitable reinforcing bar 15
There is no problem even if only one is provided. Furthermore, void 1
The pile 110 may be reinforced so that fibers such as steel and resin are mixed into the concrete 13 when the concrete 13 is poured and filled into 1a. The pile 1 constituting the precast column row wall 10
As long as the column members such as 10 can be disposed in the ground 2 before the service space 30 is excavated and formed, the column members may not necessarily be the RC concrete pipes 11 connected in series as described above. Steel pipe 1 as shown in FIG.
6, or a plain concrete pipe, etc.
The cross-sectional shape of the column material such as the pile 110 is not limited to a round shape as shown in FIG. 4 or FIG. 5, but may be a square cross-sectional shape. In addition, if the precast column row wall 10 can bear and support the earth pressure of the ground 2 as a part of the structure 7, the pile 1
The tubular members such as 10 do not have to be arranged without gaps in the excavation direction of the excavation space 3 indicated by the arrows A and B in the figure. For example, even if the entire precast column wall 10 is formed in a plate shape. No problem. That is, as shown in FIG. 5, after the steel pipes 16 are connected and arranged in series in such a manner that the steel pipes 16 are propelled in the ground 2, the precast pillar row walls 10 are connected to the plurality of steel pipes 16 which are connected and arranged in series at intervals L2. A plurality of steel pipes 16 are arranged side by side in the directions of arrows A and B, which are the directions of digging of the digging space 3, and connected and integrated around the steel pipes 16 in such a manner as to be filled with a hardening material such as concrete. You can build it. The RC concrete pipe 11
The method of propelling the unit pillars such as steel and steel pipe 16 into the ground 2 and the method of arranging the reinforcing steel bars 15 and the concrete 13 may be arbitrarily changed according to the design conditions of the structure 7.
In the above-described embodiment, since the assumed groundwater level of the ground 2 is set at the position of the arrow WL, the underground structure 1
As an advanced working pit when constructing a tunnel, an example in which the NATM cavity 5 is formed above the excavation space 3 and the shield cavity 6 is formed below the excavation space 3 has been described.
Is formed by excavation for the purpose of positioning and supporting the four corners of the structure 7 for forming the structure 7 so as to construct the structure 7 in the ground 2 safely and reliably. It is not extruded and formed in other shapes by any means.

[0014]

As described above, according to the present invention,
When constructing an underground space such as the service space 30 having a substantially quadrangular cross section in the ground 2, 4 corresponding to the cross-sectional corner of the underground space
Advanced pits such as NATM cavity 5, shield cavity 6, etc.
Each excavation is formed in the direction of excavation in the underground space, and structural members such as precast column walls 10 are installed in the ground 2 in a form to connect between advanced pits adjacent vertically and advanced pits adjacent horizontally. The underground space is formed in the ground 2 by constructing the structure 7 having a substantially square cross section and removing the ground 2 inside the structure 7 having the substantially square cross section. Before the space 30 is formed, the structure 7 can be built in the ground 2. Therefore, since the structure 7 stably supports the ground 2 prior to the formation of the service space 30, even if the large service space 30 is formed by removing the ground 2 in the structure 7 in this state. This does not collapse. And the service space 30
Has a box shape in which the upper, lower, left and right walls are formed by a structure 7 having a substantially quadrangular cross section having four advanced pits as corners, so that almost no useless space is used in the underground space. Instead, a box-shaped space cross section that is full of the area of the underground space is used as the service space 30. Therefore, according to the present invention, a limited area in the ground 2 can be used as a service space 30 very efficiently and safely without concern for affecting public roads on the ground 2a. If this is applied, for example, when constructing a highway underground, the land can be used effectively without any waste. In addition, the structural member is composed of a plurality of pillars such as a plurality of piles 110 arranged along the excavation direction of the advanced pit, and the pillars include unit pillars such as RC concrete pipes 11 in the ground 2 between the advanced pits. When the structure is constructed by connecting and arranging a plurality of series members in the form of propelling and introducing a prestress between the unit column members arranged in a plurality of series and integrating them into a columnar shape, the structure 7 is constructed. At this time, the unit pillars can be propelled one by one from the advanced pit into the ground 2 one by one and connected. Therefore, the structure 7 can be easily constructed by propulsively connecting the unit pillars using the advanced pit, and the prestress is introduced between the unit pillars,
The structure 7 can be firmly supported on the ground. At this time, since the length of the unit column material may be adjusted to an arbitrary length according to the sectional diameter of the advanced pit, it can be smoothly carried out irrespective of the design mode of the underground space. In addition, since the structural member only needs to be able to support the ground 2 as an aggregate of pillar materials integrated into a pillar shape by introducing prestress between the unit pillar materials connected in series. The diameter of itself may be small, and therefore, the work of propelling the unit pillar into the ground 2 can be easily performed. This makes it possible to construct a large underground space safely and efficiently with a short construction period, for example, in response to a special section in which the aspect ratio of the underground space to be constructed is unusual. Also,
The structural member is composed of a plurality of pillars such as piles 110 arranged along the excavation direction of the advanced pit, and the pillars push unit pillars such as RC concrete pipes 11 through the ground 2 between the advanced pits. A plurality of structural material installation spaces such as voids 11a are formed in a columnar shape by connecting and arranging a plurality of unit column materials connected in series in a form, and a concrete 13 is provided in the structural material installation space. When the structural members such as the reinforcing steel bars 15 are installed to connect and integrate a plurality of unit column members into a column shape, the structural members can reinforce the column members. Then, the strength of the structural member can be selectively increased by reinforcing the respective column members with the structural material, so that the strength of the structural body 7 can be freely set according to the earth pressure of the ground 2. This can be performed without reducing the area of the service space 30, and therefore, it is possible to simultaneously increase the safety of the service space 30 and economical efficiency of construction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an underground space constructed according to the present invention.

FIG. 2 is a plan view taken along the line II-II of FIG.

FIG. 3 is a cross-sectional side view showing an example of the construction work of the underground space shown in FIG.

FIG. 4 is a perspective view showing one example of a precast column wall portion in the underground space shown in FIG. 1;

FIG. 5 is a view showing another example of a precast column wall portion in the underground space shown in FIG. 1;

[Explanation of Signs] 2 ... ground 3 ... excavation space (underground space) 30 ... service space 5 ... NATM space (advanced well) 6 ... shield cavity (advanced well) 7 ... structure 10 ... precast Column wall (structural member) 11 RC concrete pipe (unit column material) 11a Void (structure material installation space) 110 Pile (column material) 13 Concrete (structural material) 15 reinforcement reinforcing bar ( Structural materials)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E21D 13/02 E21D 9/00

Claims (3)

(57) [Claims] When constructing an underground space having a substantially rectangular cross section in the ground, advanced pits are formed at four positions corresponding to the cross-sectional corners of the underground space, respectively, in the direction of excavation of the underground space. A structural member having a substantially rectangular cross section is constructed by installing a structural member in the ground in such a manner as to connect between an advanced mine adjacent to the ground and an advanced mine adjacent in the left-right direction, and a structure having a substantially rectangular cross section is constructed. An underground space construction method, wherein a service space is formed in the ground by removing the ground inside the ground. 2. The structural member is composed of a plurality of pillars arranged along the excavation direction of the advanced well, and the pillars are arranged in series in such a manner that unit pillars are propelled in the ground between the advanced wells. The underground space construction method according to claim 1, wherein the underground space construction method is constructed by connecting and arranging, and introducing prestress between the plurality of unit column members arranged in series to integrate them into a column shape. 3. The structural member is composed of a plurality of pillars arranged along the direction of excavation of the advanced pit, and the pillars are arranged in series in such a manner that unit pillars are propelled in the ground between the advanced pits. A plurality of unit pillars are formed by connecting and arranging the plurality of unit pillars by forming the structural material installation space in a columnar shape in such a manner as to pass through the plurality of unit pillars connected in series. The underground space construction method according to claim 1, wherein the underground space construction method is constructed so as to be connected and integrated in a columnar shape.