JP2003148082A - Method for building underground sunk structure and its reinforcing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously build a reinforcing structure section for reinforcing an afterwards formed opening section regarding an underground sunk structure built by successively pressing in and sinking press-in rings. SOLUTION: Vertical-beam storage spaces 30 extended in the vertical direction with the mutual matching of recessed sections 20 and 20 for vertical beams are formed, piling up opening-section rings 2B, 2B and the like with the recessed sections 20 for the vertical beams. Opening-section upper-side reinforcing rings and opening-section lower-side reinforcing rings are arranged to the upper and lower sections of the opening-section rings 2B, 2B and the like. The vertical beams 6 are incorporated, welded, and fixed into the vertical-beam storage spaces 30, and a frame-shaped reinforcing structure section surrounding a region in which an opening section 4 is formed is constructed.

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 submerged structure and a reinforcement structure therefor, and in particular, a plurality of press-fitting rings, which are ring-shaped deposits, are successively pressed into the ground and piled up while being piled up underground to form a shaft. In constructing the submerged structure,
The present invention relates to a construction method and a reinforcement structure suitable for reinforcing an opening that will be formed in a part of a side wall of a submerged structure after the construction.

[0002]

2. Description of the Related Art When a ring-shaped deposit is piled up by a press-fitting method to construct a vertical shaft, and then an opening is formed in a part of a side wall of the vertical shaft for connecting pipes, etc. As a secondary step, a reinforcing material is arranged around the opening-corresponding portion for the purpose of reinforcing a defective portion associated with the opening. For example, if a vertical shaft composed of an underground structure is constructed, H steel is built vertically and horizontally so as to surround the periphery of the opening inside the vertical shaft, and the H steel is added to the opening as a beam member. Reinforcement structure for carrying load is performed.

In this structure, since the H steel is projected into the shaft, the effective inner diameter of the shaft is restricted, and H
Since the steel installation work is performed in the mine, workability is poor and the construction period must be extended.

From the above, for example, Japanese Patent Laid-Open No. 2000-2000
No. 170170, a lower horizontal reinforcement including a reinforcement piece that reinforces the lower side of an opening when stacking a plurality of press-fitting rings formed by combining a plurality of segment pieces while sequentially press-fitting and sinking. Along with the ring being sunk, a vertical reinforcing ring including reinforcing pieces that reinforce both sides of the opening is sunk on it, and an upper horizontal reinforcing ring similar to the lower horizontal reinforcing ring is sunk on it, and finally A technique has been proposed in which a reinforcing bar is incorporated so as to penetrate each reinforcing piece, concrete is then driven, and a reinforcement structure for an opening is simultaneously constructed in the process of substantially constructing a submerged structure.

In this method, since it is essential to pour concrete, not only the number of working steps is long, but also a curing period is required, and the working period becomes long, which is not preferable.

The present invention has been made in view of the above problems, and it is possible to construct a reinforcing structure for an opening at the same time in the process of constructing an underground submerged structure without the need to drive concrete. The present invention intends to provide a method for constructing a submerged underground structure and a reinforcing structure.

[0007]

The invention according to claim 1 is constructed as a cylindrical wall body by sequentially stacking the press-fitting rings into the ground while stacking the press-fitting rings in multiple stages, and after the construction. Assuming a method of constructing an underground deposit structure in which an opening is formed so as to straddle a plurality of stages of press-fitting rings in a part of the side wall, a vertical beam is provided at a site to be located on both sides of the opening equivalent position. In the step of press-fitting and depressing the opening lower side reinforcement ring which is preliminarily formed with the concave portion for reinforcement and which reinforces the lower side of the position corresponding to the opening portion, and in the portion to be located on both sides of the position corresponding to the opening portion. Regarding the opening ring in which the vertical beam recess is formed in advance, the opening is formed by the number of steps involved in the formation of the opening while aligning the position of the vertical beam recess with that on the opening lower reinforcement ring side. The step of stacking while sequentially press-fitting and lowering on the lower reinforcing ring, and the vertical beam recesses are previously formed in the portions to be located on both sides of the opening equivalent position, and the upper side of the opening equivalent position is Regarding the opening upper side reinforcing ring to be reinforced, a step of press-fitting and depressing on the opening ring while aligning the position of the vertical beam recess with that of the opening ring side; For the vertical beam accommodation space formed with alignment, a vertical beam of a length that straddles the above-mentioned opening lower reinforcing ring, multiple steps of the opening ring, and the opening upper reinforcing ring is arranged inside each ring so as to match with this. And a step of reinforcing by assembling.

The invention described in claim 2 is the same as claim 1.
The invention described in (1) is substantially regarded as a reinforcing structure, and while the press-fitting rings are sequentially press-fitted and submerged in the ground, the press-fitting rings are stacked in multiple stages to be constructed as a tubular wall body, and the side wall after the construction. A reinforcing structure for an underground submerged structure in which an opening is formed so as to straddle a plurality of stages of press-fitting rings in a part of Is formed in advance and reinforces the lower side of the position corresponding to the opening, and the lower reinforcing ring for the opening is formed in advance on the portions to be positioned on both sides of the position corresponding to the opening. And the vertical beam recesses were sequentially stacked on the opening lower reinforcement ring by the number of steps involved in the formation of the opening so that the positions of the vertical beam recesses were aligned with those on the opening lower reinforcement ring side. There are several stages of opening rings and vertical beam recesses are formed in advance at the portions to be located on both sides of the opening equivalent position, and the positions of the vertical beam recesses are aligned with those on the opening ring side. And an opening-side upper reinforcing ring that reinforces the upper side of the opening-corresponding position by being arranged on the opening-ring.

With respect to the vertical beam accommodating space formed by aligning the vertical beam concave portions with each other, the opening lower reinforcing ring, the plurality of openings ring and the opening upper reinforcing ring are aligned and matched. It is characterized in that a vertical beam with a length that spans the inside is reinforced by incorporating it from the inside of each ring.

Here, except when the opening ring itself has the same strength as the opening lower reinforcing ring and the opening upper reinforcing ring, the opening lower reinforcing ring and the opening upper reinforcing ring are Due to its function, it is preferable that the pressure resistance strength in the horizontal direction is higher than that of the opening ring. Further, the vertical beam incorporated in the vertical beam accommodating space is welded and joined to the underground underground structure over the entire circumference thereof.

Therefore, in the inventions according to claims 1 and 2, since the vertical beam accommodating space is formed in the process of stacking the required number of press-fitting rings, the stacking of the required number of press-fitting rings is completed. By incorporating a vertical beam having a length that extends over the press-fitting rings of a plurality of stages from the inside of the press-fitting ring so as to match the vertical beam accommodation space, the vertical beam, the opening lower reinforcement ring, and the opening upper reinforcement ring With the above, a reinforcing structure for the opening is constructed.

According to a third aspect of the invention, on the premise of the second aspect, the opening lower reinforcing ring, the opening ring, and the opening upper reinforcing ring all connect a plurality of steel segments to each other. In the above-mentioned vertical beam recess, the narrow steel segment having an inner peripheral length equal to the outer peripheral length of the vertical beam is connected to the steel segment of the general portion adjacent to it. In order to enable the vertical beams to be installed from the inside of each ring, the circumferential length on the opening side of the vertical beam recess is equal to or greater than the circumferential length on the back side. Is also characterized by being formed large.

The invention according to claim 4 is the same as claim 3
Assuming the description above, in the state where the vertical beam is incorporated in the vertical beam accommodation space formed by aligning the vertical beam concave portions with each other, the inner circumferential surface of the vertical beam is substantially flush with the inner circumferential surface of each ring. It is characterized by being set to be eggplant.

Therefore, in the inventions according to the third and fourth aspects, after assembling each ring with a plurality of steel segments on the ground, the rings are sequentially press-fitted into the ground to be submerged in the underground structure. Is built.

Here, if both side surfaces in the circumferential direction of the vertical beam recess are formed so as to have planes that direct the axial center of each ring, the circumferential length of the vertical beam recess on the opening side will be It becomes smaller than the circumference of the back part side, and it becomes impossible to incorporate a vertical beam that matches the vertical beam accommodation space from the inside of each ring. Therefore, in the invention according to claim 3, in order to enable incorporation of the vertical beam from the inside of each ring, the circumferential length on the opening side of the vertical beam recess is equal to or greater than the circumferential length on the back side. Also needs to be formed large.

At the same time, it is not preferable that the vertical beams project to the inside of each ring, since this limits the effective inner diameter of the underground submerged structure constructed with these rings. In the invention according to claim 4, in the state where the vertical beam is incorporated in the vertical beam accommodation space formed by aligning the vertical beam concave portions with each other, the inner circumferential surface of the vertical beam has an inner circumferential surface of the reinforcing deposit. The condition is that they are set to be substantially flush with the plane.

According to a fifth aspect of the present invention, on the premise of the third or fourth aspect, the steel segment has at least a pair of upper and lower main girders extending in the circumferential direction, and both end portions of these main girders. A pair of left and right joint plates that connect the members to each other and a plurality of vertical ribs extending in the same direction as the joint plate and a skin plate that functions as an outer surface layer portion are formed. Of the main girder, a pair of left and right side plates connecting both ends of these main girders, and a plurality of vertical ribs extending in the same direction as the side plates.

That is, since the vertical beam is accommodated in the vertical beam accommodation space formed by aligning the vertical beam recesses with each other so as to overlap with the vertical beam accommodation space, in the invention according to claim 5, at least the vertical beam is provided. Clarifies that no skin plate is needed.

[0019]

According to the first and second aspects of the present invention, the reinforcing structure of the opening is constructed only by incorporating the vertical beam in the vertical beam accommodation space formed by stacking the required number of press-fitting rings. Therefore, there is no need for the conventional arrangement of reinforcing bars, concrete driving, and the curing period associated therewith, which has the advantage of being able to greatly contribute to the reduction of man-hours and the construction period.

According to the third aspect of the present invention, since each ring is formed by connecting a plurality of steel segments to each other, while assembling the rings on the ground, the rings are sequentially press-fitted into the ground. Will be able to
The workability and handleability are further improved, and since the vertical beam can be incorporated into the vertical beam accommodation space from the inside of each ring, the assembling workability is also very good.

According to the fourth aspect of the invention, when the vertical beam is incorporated in the vertical beam accommodating space, the inner circumferential surface of the vertical beam is set to be substantially flush with the inner circumferential surface of each ring. Therefore, the effective inner diameter of the constructed underground structure is not restricted by the arrangement of the vertical beams.

[0022]

1 and 2 are views showing a preferred embodiment of the invention. A schematic structure of an underground submerged structure (hereinafter, simply referred to as a submerged structure) 1 constructed by a steel segment press-in construction method. Is shown.

As shown in the figure, the submerged structure 1 is formed by stacking a plurality of vertical cylindrical press-fitting rings 2, 2 ... By fastening each other with a bolt and a nut, a tubular wall body having a depth several times larger than the diameter is formed. Further, each press-fitting ring 2, 2 ... Is divided into a plurality of steel segments having an arcuate shape in the circumferential direction as described later, and the steel segments are fastened to each other in advance by using bolts and nuts. The press-fitting rings 2, 2 ... Are assembled.

After the construction of the submerged structure 1, for example, a plurality of press-fitting rings 2, for connection with another pipeline 3.
The circular opening 4 is formed by cutting off a part of the opening so as to straddle the two. However, in the present embodiment, prior to the formation of the opening, a portion to be the opening 4 is formed. A frame-shaped reinforcing structure portion (a hatched portion in FIGS. 1 and 3) 5 is formed so as to surround it from above, below, left and right at the same time during the construction stage of the sinking structure 1. The opening 4 is formed by melting or the like from the inside of the submerged structure 1 after construction.

In the present embodiment, as the press-fitting rings 2, 2, ..., In addition to the general part rings 2A, 2A .. .., an opening lower reinforcing ring 2C and an opening upper reinforcing ring 2D which are located on the lower side and the upper side of the portion where the opening 4 is formed to reinforce the ring 2B, 2B, ... Blade ring 2E
In addition, a pair of left and right vertical beams 6 to be incorporated later are also used so as to straddle the opening lower reinforcement ring 2C and the opening upper reinforcement ring 2D. The opening lower reinforcement ring 2C, the opening upper reinforcement ring 2D, and the vertical beam 6 form the frame-shaped reinforcement structure 5 described above.

As a construction procedure for constructing the above-mentioned submerged structure 1, as shown in FIG. 1, the lowermost blade edge ring 2E having the blade edge 7 is installed on the ground surface G at the construction site, and above it. The lower reinforcement ring 2C of the opening is piled up to form an intermediate assembly, and the intermediate assembly is press-fitted into the ground by using a hydraulic press-fitting device (not shown). Then, after press-fitting, the sand inside the intermediate assembly is excavated by using, for example, a bucket excavator.

Subsequently, the opening rings 2B of one or two steps are stacked on the intermediate assembly to increase the number of ring steps as the intermediate assembly, and then press-fitted and depressed again by the increased number of ring steps in the same manner as above. Then, the earth and sand inside the intermediate assembly are excavated. Then, the deposition structure 1 as shown in FIG. 1 is constructed by sequentially repeating such stacking of one or more stages of press-fitting rings 2, press-fitting and submersion in the ground, and internal excavation.

Here, the general part rings 2A, 2A ...
Are constituted by abutting the arc-shaped steel segments 12, 12, ..., Which are divided into six equal parts as shown in FIGS. 3 and 4, and fastening them together with bolts and nuts. These general part rings 2A, 2A At the time of stacking ..., As shown in FIG. 1, the steel segments 12, 12 ... Are alternately arranged such that the phases of the abutting portions of the steel segments 12, 12 ... As shown in FIG. 5, the individual steel segments 12, 12 ... Which compose the general portion ring 2A have a pair of upper and lower main girders 13, 13 and a pair of left and right joint plates 1 as shown in FIG.
4 and 14, and a plurality of vertical ribs 15 having a substantially L-shaped cross section and arranged in parallel with the joint plates 14 and 14, and a skin plate 16 forming an outer surface, the main girder 13, A plurality of bolt holes 17 are formed in 13 and the joint plates 14 and 14 for bolt connection with the steel segment on the other side.

On the other hand, the opening lower reinforcement ring 2C, the opening ring 2B and the opening upper reinforcement ring 2D have basically the same structure, and as shown in FIGS. In addition to the four steel segments 12, 12, ..., One pair of left and right adjusting segments 18, 18 with one end tapered and a pair of right and left vertical beam installing segments 19, 19 By abutting each other and fastening each other with bolts and nuts,
It is configured as having left and right vertical beam recesses 20.
When the opening lower reinforcement ring 2C, the opening rings 2B, 2B ... And the opening upper reinforcement ring 2D are respectively stacked, the vertical beam recesses 20, 20 ...
They are stacked so that they match each other. At the same time, the inner side surfaces 20a, 20a of the vertical beam recesses 20, 20, ...
Are set to be parallel to each other. This is because in order to incorporate the vertical beam 6 from the inside into the vertical beam housing space 30 formed by a plurality of vertical beam recesses 20, 20, ... This is because it is necessary to form the circumference of the same as or larger than the circumference of the inner side.

FIG. 7 shows the details of the adjustment segment 18 and FIG. 8 shows the details of the vertical beam installation segment 19, both of which, like the steel segment 12 shown in FIG. Or main girder 2 with three pieces
1, 21 and a pair of left and right joint plates 22, 22, as well as a plurality of vertical ribs 23, 23 having a substantially L-shaped cross section and arranged in parallel with the joint plates 22, 22, and a skin plate 24 constituting an outer surface. , And a plurality of bolt holes 25, 25 ... Are formed in the main girders 21, 21 and the joint plates 22, 22.

However, the vertical beam installation segment 19,
Since 19 forms the vertical beam recess 20, the width dimension of the main girders 21, 21 and the joint plates 22, 22 is set to about half that of the other segments 12, 18. Also,
Steel segments 12, 1 that will constitute the opening lower reinforcing ring 2C and the opening upper reinforcing ring 2D
2 and the adjusting segments 18 and 18 and the vertical beam installing segments 19 and 19 are, in view of their functions, particularly the main girders 13, as compared with those on the opening ring 2B, 2B side.
The plate thickness of 21 and the like is set to be large to improve its strength.

Therefore, by stacking the required number of opening rings 2B, 2B ... With the opening lower reinforcing ring 2C and the opening upper reinforcing ring 2D as described above, the vertical beam recesses of the respective rings 2C, 2D, 2B. 20, 20
A pair of left and right vertical beam accommodating spaces 30 having a length corresponding to the number of ring steps are formed by matching and matching each other.

In this way, a pair of left and right vertical beam accommodating spaces 30 and 30 are formed together with the opening lower side reinforcing ring 2C and the opening upper side reinforcing ring 2D which are a part of the reinforcing structure portion 5 in the process of constructing the submerged structure 1. Then, as shown in FIG. 9 in addition to FIGS. 1 to 3, the vertical beams 6 are incorporated and fixed in the vertical beam accommodation spaces 30, 30 from the inside.

As shown in FIG. 10, the vertical beam 6 has a vertically long length which can match the vertical beam accommodation space 30 with a plurality of stages of main girders 31, 31, ..., A pair of left and right side plates 32, 32 and vertical ribs 33, 33. Formed as a frame structure of FIG.
As shown in FIG. 4, the entire circumference of the vertical beam housing space 30 is assembled by welding from the inside and then welded. As a result, the reinforcing structure portion 5 is formed so as to surround the region to be the opening 4 with the opening lower reinforcing ring 2B, the opening upper reinforcing ring 2D and the vertical beam 6.

After that, when the submerged structure 1 is submerged to a predetermined depth, the opening 4 is opened from the inside of the submerged structure 1 by means of fusing or the like so as to straddle the plurality of opening rings 2B, 2B ... Form. At this time, the opening ring 2
As the main girders of B, 2B ... Are partially cut and removed, the load bearing capacity of the opening rings 2B, 2B .. It is possible to compensate for the reduction in strength by dispersing and loading the load that should be originally loaded by the opening rings 2B, 2B ... In the structural portion 5.

As described above, according to the present embodiment, since the reinforcing structure 5 is constructed around the opening 4 at the same time in the process of constructing the submerged structure 1, the number of steps is reduced as compared with the conventional construction method. The work period can be shortened.

[Brief description of drawings]

FIG. 1 is a view showing a preferred embodiment of the present invention and is a front explanatory view of an underground deposit structure.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged explanatory view of a main part of FIG. 1.

FIG. 4 is an enlarged cross-sectional view taken along the line BB of FIG.

5A is an enlarged cross-sectional view of a steel segment that constitutes the general portion ring of FIG. 4, and FIG. 5B is a front explanatory view thereof.

6 is an enlarged cross-sectional view taken along the line CC of FIG.

7A is an enlarged cross-sectional view of an adjustment segment that constitutes the opening ring of FIG. 6, and FIG. 7B is a front explanatory view thereof.

8A is an enlarged cross-sectional view of a vertical beam installation segment that constitutes the opening ring of FIG. 6, FIG. 8B is a front explanatory view thereof, and FIG. 8C is a left side view thereof.

9 is an explanatory sectional view when assembling a vertical beam from the state of FIG.

10 (A) is an enlarged cross-sectional explanatory view of the vertical beam shown in FIG. 9,
(B) is the front explanatory view.

FIG. 11 is an explanatory cross-sectional view showing a state in which the vertical beams have been assembled from the state shown in FIG.

[Explanation of symbols]

1 ... Underground structure 2 ... Press-fit ring 2A ... General section ring 2B ... Opening ring 2C ... Reinforcement ring under opening 2D ... Reinforcement ring on top of opening 4 ... Opening 5 ... Reinforcing structure 6 ... Vertical beams 12 ... Steel segment 13 ... Main girder 14 ... Joint plate 15 ... Vertical ribs 16 ... Skin plate 18 ... Adjustment segment 19 ... Segment for vertical beam installation 20 ... Recess for vertical beam 21 ... Main girder 22 ... Joint plate 23 ... Vertical ribs 24 ... Skin plate 30 ... Vertical beam housing space 31 ... Main girder 32 ... Side plate 33 ... Vertical rib

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoru Tamura             Aichi prefecture Kanie-cho Kanie-cho large section Kanie new field lower market             No. 1 at Kato Construction Co., Ltd. (72) Inventor Kazuyoshi Sato             6100, Sankajiri, Kumagaya-shi, Saitama Japan Steel             Tube Light Steel Co., Ltd. (72) Inventor ▲ Tsuru ▼ Akitoshi Mimi             6100, Sankajiri, Kumagaya-shi, Saitama Japan Steel             Tube Light Steel Co., Ltd.

Claims (5)

[Claims] 1. A cylindrical wall body is constructed by stacking the press-fitting rings in multiple steps while sequentially substituting the press-fitting rings into the ground, and after the construction, a part of the side wall extends over the multi-stage press-fitting rings. A method for constructing an underground deposit structure in which an opening is formed, in which a vertical beam recess is formed in advance at a portion to be located on both sides of the opening equivalent position, and the opening is equivalent to the opening. Regarding the step of press-fitting and depressing the opening lower side reinforcing ring that will reinforce the lower side of the position, and the opening ring in which the vertical beam recesses are pre-formed in the portions to be located on both sides of the opening corresponding position While sequentially aligning the positions of the vertical beam recesses with those on the opening lower side reinforcement ring side, while sequentially press-fitting and depressing on the opening lower side reinforcement ring by the number of steps involved in the formation of the opening portion Overlap step and opening upper side reinforcement ring in which vertical beam recesses are pre-formed in portions to be located on both sides of the opening equivalent position and which reinforces the upper side of the opening equivalent position The step of press-fitting and depressing the vertical beam recesses on the opening ring while aligning the positions of the vertical beam recesses with those on the opening ring side, and the vertical beam accommodating space formed by aligning the vertical beam recesses with each other. , A vertical beam having a length extending over the opening lower side reinforcement ring, the plurality of steps of the opening ring and the opening upper side reinforcement ring so as to be matched and matched therewith is reinforced by being incorporated from the inside of each ring. A method for constructing an underground submerged structure, characterized by: 2. A tubular wall body constructed by stacking the press-fitting rings in multiple steps while sequentially substituting the press-fitting rings into the ground, and after the construction, straddles a plurality of press-fitting rings on a part of the side wall. A reinforcement structure for an underground submerged structure in which an opening is formed, and a vertical beam recess is formed in advance at a position to be located on both sides of the position corresponding to the opening, and the position corresponding to the opening is provided. The lower part of the opening for reinforcing the lower part of the opening and the concave part for the vertical beam are formed in advance at the portions to be located on both sides of the position corresponding to the opening. A plurality of opening rings sequentially stacked on the opening lower reinforcing ring by the number of steps involved in forming the opening so as to be aligned with the opening lower reinforcing ring side, and the opening equivalent position. The vertical beam recesses are formed in advance at the portions to be located on both sides of the opening ring, and the vertical beam recesses are arranged on the opening ring so that the positions thereof are aligned with those on the opening ring side. By virtue of this, the upper part of the opening corresponding to the opening is reinforced, and the upper part of the upper part of the opening is reinforced. In order to reinforce the underground submerged structure, a vertical beam having a length that spans the opening lower reinforcement ring, the multi-tiered opening ring, and the opening upper reinforcement ring is incorporated from the inside of each ring to reinforce. Construction. 3. The lower opening reinforcing ring, the upper opening ring, and the upper opening reinforcing ring are each formed as a ring shape by connecting a plurality of steel segments to each other. The recess is formed in a concave shape by connecting a narrow steel segment having an inner peripheral length equivalent to the outer peripheral length of the vertical beam and a steel segment of a general part adjacent to the narrow steel segment, and from the inside of each ring. The perimeter on the opening side of the vertical beam recess is formed to be the same as or larger than the perimeter on the back side so that the vertical beam can be incorporated. Reinforcement structure of underground underground structure. 4. An inner peripheral surface of the vertical beam is substantially flush with an inner peripheral surface of each ring in a state where the vertical beam is incorporated in a vertical beam accommodating space formed by aligning the vertical beam concave portions with each other. The reinforcing structure for an underground deposit structure according to claim 3, wherein the reinforcing structure is set as follows. 5. The steel segment comprises at least a pair of upper and lower main girders extending in the circumferential direction, a pair of left and right joint plates connecting both ends of these main girders, and in the same direction as the joint plate. On the other hand, the vertical beam is formed of a plurality of extending vertical ribs and a skin plate that functions as an outer surface layer portion. On the other hand, the vertical beam includes at least a pair of upper and lower main girders and a pair of left and right connecting both end portions of these main girders. 5. The reinforcement structure for an underground deposit structure according to claim 3 or 4, wherein the side plate is formed of a plurality of vertical ribs extending in the same direction as the side plate.