JP2577439B2 - Construction method of branch support in tubular wall for excavation hole lining - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a branch support formed on a branch of a cylindrical wall assembled by segments when lining multiple drill holes. It concerns the construction method.

[Conventional technology]

In recent years, as a large-section shield method for constructing a large-section tunnel structure such as a railway tunnel, a so-called double-circle special-section shield method has come into practice. This method uses a shielded excavator with a structure in which two cylindrical shielded excavators are connected, and excavates the ground or ground into a cross-sectional shape that is continuous with two circles partially overlapping. A segment is assembled on the inner surface of the excavated hole to form a cylindrical wall body (primary lining), and a gap is filled between the back of the segment for the primary lining, that is, the segment and the ground. After filling the material, concrete is rolled up on the inner surface of the primary lining (secondary lining), and the ground is supported by them to form a predetermined inner space.

Conventionally, as this type of cylindrical wall, FIGS.
The one shown in the figure was proposed. Reference numeral 1 in FIG.
Is a main wall portion, and arc-shaped PC (precast concrete) segments 2 are bolted in the length direction (the direction in which the arc is formed) and the width direction. Joint fittings 3 are embedded in each joint surface of the segment 2, and insertion holes 3 a for inserting bolts are formed in these joint fittings 3. Reference numerals 4 and 5 denote branch segments having a substantially Y-shaped cross-section, which are disposed above and below the cylindrical wall body for connecting the left and right main wall portions 1.
The middle pillar 6 made of PC is connected between them. Joint fittings 3 having insertion holes 3a are also buried in the joint surfaces of the branch segments 4, 5 and the middle pillar 6, respectively. In FIG. 6, only the cross section of the cylindrical wall of the segment 2, the branch segments 4, 5 and the middle pillar 6 as viewed from the axial direction is shown, but they are connected in the circumferential direction of the cylindrical wall. Insertion holes on the end face
The joint fitting 3 having 3a is embedded therein.

Next, FIGS. 7 and 8 show the structure of the joint between the upper and lower end branching segments 4 and 5 and the middle pillar 6 in the cylindrical wall. FIG. 7 is a front view as viewed from the direction of the excavation operation, and FIG. 8 is a side view.

An example of a method of assembling the cylindrical wall will be described with reference to FIG. First, the segments 2 are sequentially bolted to the left and right of the lower end branch segment 5 in the circumferential direction to form left and right main wall portions 1, and then the upper end branch segment 4 is connected to the main wall portion 1.
After being bolted to the upper ends of the left and right openings, the middle pillar 6 is attached between the upper branch segment 4 and the lower branch segment 5. In order to attach the center column 6, the upper end branch segment 4 is supported by a lifting machine such as an erector, and the center column 6 is further divided by the other lifting machine into the two branch segments 4,5.
Adjust the position of the bolt insertion hole 3a while inserting it between
As shown in the figure, the bolts are connected between the adjacent fittings 3.

In this way, the lining body is constructed in a ring shape in the shield machine, and each time the shield machine is excavated, the tubular wall body is extended while the lining body assembled in the ring shape is bolted in the axial direction.

In the above, the case where the branch portion support is a pillar (the middle pillar 6) has been described, but the same applies to the case where the branch portion support is a wall.

[Problems to be Solved by the Invention] By the way, the following inconvenience has occurred in the method for constructing the branch portion support described above.

That is, since the tubular wall body has a construction error due to its own weight and the pressure of the ground, etc., the upper end branch section 4 is supported by the hoisting machine, and the center pillar 6 is further mounted by another hoisting machine.
It is necessary to adjust the position of the bolt insertion hole 3 a while positioning the bolt between the two branch portions 4 and 5, and to perform the bolt connection between the adjacent joint fittings 3. Therefore, in the above method, there is a waste that one lifting machine is used only for supporting the upper end branch segment 4, and the working efficiency is reduced accordingly. In addition, when the center pillar portion is made of precast concrete, the shape of one piece becomes longer and the weight increases, so that there is a problem that it is difficult to assemble.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to realize a method for constructing a branch portion support, which can solve the above-mentioned disadvantages and can be efficiently constructed with excellent workability.

[Means for solving the problem]

The method of constructing a branch portion support in a tubular wall body for lining an excavation hole according to the present invention is directed to a multiple drilling hole in which a plurality of excavation holes having a circular cross section are formed so that their side portions overlap each other. In order to perform the lining, a branch support such as a pillar is provided between the upper branch and the lower branch provided respectively at the upper and lower openings of the overlapping portion of the plurality of excavated holes. In constructing the body, between the two branch portions segment, provided in the length direction, a mold for forming the support that is configured to be able to be divided in both the width direction, the mold to support the upper end branch segment. Further, concrete is poured into the mold, and after the concrete is cured, the mold is released from the mold to form a support.

In carrying out the above method, at least one of the divided surfaces for dividing the mold in the length direction is used as the mold.
It is preferable to use a structure in which the portion is inclined with respect to a plane orthogonal to the axis of the formwork.

[Action]

Since the formwork is divided in the length direction and the width direction, it can be provided below the upper end branch segment even after the upper end branch segment is fixed in a completed state. In addition, since the upper end branch segment is supported by the formwork, no support work is required.

When the mold has a configuration in which at least one part of a dividing surface for dividing the mold in the length direction is inclined with respect to a plane orthogonal to the axis of the mold, It is easy to install and remove the mold.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
The present invention is applied to a tubular wall for lining a continuous excavation hole, and a column is shown as an example of a branch portion support according to the present invention. In the figure, reference numeral 4 denotes an upper branch portion segment, and 5 denotes a lower branch segment.
Are the same as those described above with reference to FIG. The formation of a middle pillar (branch support) between the upper branch segment 4 and the lower branch segment 5 is performed as follows.

First, the upper end branch segment 4 is fixed to the segment 2 at a predetermined position. That is, it is in the state at the time of completion.

When the upper branch portion segment 4 is fixed to the segment 2, a column forming form 10 is installed between the upper branch portion segment 4 and the lower end segment 5.

This formwork 10 is for forming a target center pillar, and has a cross-sectional shape of the center pillar to be constructed (in this embodiment, a rectangular shape).
Is divided into two parts from the center to the left and right along the axis of the hollow part, and the length is exactly the dimension between the upper branch segment 4 and the lower branch segment 5. The mold 10 is also vertically divided into two parts at a substantially central portion in the longitudinal direction. As shown in FIG. 3, a radially projecting collar is provided on the axial dividing surface.
11 are formed, and the inside of the pillar section (rectangular shape) is formed by joining the two flanges 11 together and bolting them together. The upper end and the lower end of the form 10 are respectively provided with flanges which are in contact with the joint end face 4a of the upper branch segment 4 and the joint end face 5a of the lower branch segment 5, respectively.
12,13 are formed. The flanges 12 and 13 are formed with insertion holes 12a and 13a (only 13a is shown) through which bolts are passed. Bolts 14 are inserted into the insertion holes 12a and 13a, and the respective flanges 12 and 13 are closed at upper ends. It is fixed by being connected to the branch segment 4 and the lower branch segment 5. Although not shown, both branch segments 4,
Inserts for fixing the bolts 14 are buried in the respective joint end surfaces 4a and 5a. Further, similar flanges 15 and 16 are also formed on the division surface in the length direction, and the flanges 15 and 16 are integrated by connecting the flanges 15 and 16 with bolts 17.

However, the divided surfaces divided in the vertical direction, that is, the flanges 15 and 16 are not horizontal, but are slightly inclined with respect to a plane orthogonal to the axis of the formwork as shown in the figure. . Reference numeral 18 denotes a rib for reinforcing the flange portion, 19 denotes a concrete inlet for placing concrete, and 20 denotes an air vent.

The installation of the formwork 10 is performed by dividing one of the two parts into upper and lower parts, for example, the lower part, and joining the flange 13 to an end face.
After being fixed to the lower branch portion segment 5 by being joined to the lower end branch portion 5 with a bolt 14, the other is connected above it. This connection is made by connecting the flange 12 to the upper end branch segment 4.
And a flange 15 located at a position facing the flange 12 and a flange 16 located at the upper end of the previously fixed lower formwork.
Perform by fixing with 17. At this time, since the flanges 15 and 16 formed on the joining surfaces of the upper and lower divided formwork are not inclined but attached horizontally, the upper one attached later is as shown in FIG. , Can be moved horizontally so as to match the direction of inclination from the side and connected to the lower side.

When the installation of the formwork 10 is completed, the formwork 10 itself acts as a support for supporting the vertical load applied to the upper end branch segment 4. When the installation of the formwork 10 is completed, concrete is poured into the formwork 10 from the concrete input port 19.

When the cast concrete has hardened and the required strength has been obtained, the above-described formwork 10 is dismantled in a procedure reverse to the above-described assembling procedure. Thereby, the target pillar is completed.

If the middle pillar constituted by the branch part is constructed by the above method, the upper end branch part segment 4 is fully tightened in advance and installed, and then the formwork 10 is installed thereunder as a support, and the vertical load is applied to the formwork. Can be used as a temporary column, and then concrete can be poured into the formwork 10 to form a middle column. Therefore, a lifting machine for supporting the upper end branch segment 4 is separately provided. Since it is not necessary, cost can be reduced, and since a heavy secondary product (precast concrete product) is not handled, efficient work can be performed. Furthermore, since the excavation of the excavation hole is performed sequentially with the excavation of the shield machine, the formwork 10 can be diverted one after another as the lining progresses, further improving the efficiency. Can be achieved.

FIG. 5 shows another shape of the formwork, corresponding to the case where the center pillar is a cylinder. Formwork 10 'of this embodiment
Has the same configuration as the mold 10 according to the first embodiment except that the inner space formed by the mold 10 'is circular in cross section, and the same effect as the mold 10 can be obtained. it can.

By installing various inserts buried in concrete inside the formwork in advance, the constructed middle pillar can be provided with a decorative panel, a hanging metal fitting, and the like. Further, in the embodiment, the branch portion support is described as the middle pillar, but the same effect as described above can be obtained when this is used as a wall (middle wall). In the embodiment, the mold is divided into two parts in the length direction. However, the form is not limited to two parts, and may be further divided if necessary. However, even in such a case, in order to facilitate the assembling and removing of the mold, it is preferable that at least one of the divided surfaces is inclined as described above. Furthermore, although the embodiment has been described assuming that the segments 2 are made of concrete, it goes without saying that the present invention can achieve the same effect even if they are steel segments.

〔The invention's effect〕

As described above, according to the first aspect of the present invention,
Even after fixing the upper end branch segment to the state at the time of completion, the formwork can be provided between the two branch part segments, and the formwork itself is used as a support to cause the formwork to function as a temporary column, Thereafter, concrete can be poured into the formwork to form the branch support, so that a separate lifting machine for supporting the upper branch segment is not required, thereby reducing costs and reducing weight. Efficient work can be done because there is no need to handle certain secondary products. In addition, since the excavation of the excavation hole is performed sequentially with the excavation of the shield machine, the formwork can be diverted one after another as the lining progresses, thereby further improving efficiency. It will be.

Further, according to the second aspect of the present invention, the installation and removal of the mold are extremely easy, so that the work efficiency in the above effects is further promoted.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a partial front view showing a branch portion of a cylindrical wall together with a mold, FIG. 2 is a side view of FIG. 1, and FIG. Partial perspective view of frame, fourth
The figure is a partial side view showing the formwork according to the second aspect of the present invention.
The drawings are partial perspective views showing a mold having another configuration, FIGS. 6 to 8 illustrate the prior art, FIG. 6 is an overall front view of a cylindrical wall, and FIG. 7 is a cylindrical wall. FIG. 8 is a partially enlarged front view showing a fork of the body, and FIG. 8 is a side view thereof. 4 Upper end branch segment 5 Lower end branch segment 6 Middle pillar (branch support) 10, 10 '... Formwork.

Claims (2)

(57) [Claims] 1. An opening at an overlapping portion of a plurality of excavated holes for lining a plurality of excavated holes, each having a plurality of excavated holes having a circular cross section and formed such that their side portions overlap each other. In constructing a support such as a column between the upper and lower branch segments respectively disposed at the upper and lower ends of the upper and lower branch segments, a length direction and a width direction are provided between the two branch segments. A mold for forming the support, which is configured to be dividable together, is provided, the upper end branch segment is supported by the mold, and concrete is poured into the mold, and after the concrete is hardened, the mold is formed. A method of constructing a branch support in a tubular wall for lining an excavation hole, wherein the support is formed by removing a frame. 2. The method for constructing a branch portion support according to claim 1, wherein at least one part of a dividing plane dividing the mold in a length direction is a plane orthogonal to an axis of the mold. A method for constructing a branch support in a tubular wall for lining an excavation hole, characterized by using a structure that is inclined with respect to a wall.