JPS63312437A - Construction of underground structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention is applicable to construction methods for underground structures, especially underground construction on soft ground, large scale, and deep underground that requires the adoption of the reverse construction method. This relates to construction methods for structures.

(Prior Art) In the construction method of a general underground structure, temporary shoring is provided for a temporary earth retaining wall, a temporary pier is installed, and underground excavation is performed.

However, when it comes to large-scale, deep underground excavations in soft ground, it is difficult to carry out construction using the conventional temporary construction method, and in order to ensure safety, the omnipotent reverse method is often adopted. With the reverse casting method, formwork was assembled on-site, reinforcing bars were placed, and concrete was poured for each floor structure work in the underground section.

(Problems to be Solved by the Invention) As described above, in the conventional construction method, cast-on-site forms are assembled, reinforcement is arranged, and concrete is poured each time for underground sub-assembly construction work. The support of the upper floors is unstable, and unless the strength of the upper floor concrete exceeds a certain limit, demolition and root cutting of the lower level cannot be done, and furthermore, once the dismantled formwork materials have been carried to the upper floor, cleaned up, and the roots have been cut down. , the work of moving to the lower floor again is complicated.

As a result, reversing work is extremely time-consuming, increases construction costs, and causes delays in the process.

(Means for Solving the Problems) The present invention was proposed in order to solve the above problems. The required number of tiers of PC beams are overlapped and suspended so that they can descend freely, each of the same PC beams is lowered to the bottom of the first root cutting, and the first tier of PC beams at the top are fixed between each of the vertical members. The first floor slab was constructed on top of each of the first stage PC beams, and then the second root cutting was carried out, and the PC beams from the second stage onwards were suspended to the bottom of the second root cutting. lowering the second stage PC beam, fixing it between the respective vertical members, constructing a slab for the first basement floor on the second stage PC beam, and repeating the same process as described above. This relates to construction methods for structures.

(Function) As described above, in the present invention, after constructing vertical members in the ground, such as an outer circumferential continuous underground wall that also serves as a support pile, a support pillar, etc., the first root cutting is performed, and each of the above-mentioned between the vertical members,
The number of PC beams corresponding to the number of underground floors are stacked and suspended so that they can descend freely, and each of the PC beams is suspended in a stacked state to the bottom of the first root cutting, and the highest of the stacked PC beams is suspended. The upper first-stage PC beam is fixed to each of the vertical members, a slab formwork is erected on the first-stage PC beam, and slab concrete for the first floor above ground is poured.

After completing the construction of the first floor slab, the second floor
Perform the next root cutting, and suspend the PC beams of the second stage and below that are located below the first stage PC beam in a superimposed state to the bottom of the second root cutting, and among the PC beams in the same superposed state After fixing the second stage PC beam located at the top between each of the vertical members, do the same as above on the second stage PC beam [Underground 1
Construct the floor slab, and repeat the same process as above for the required floors.
By repeating the process, an underground structure is constructed.

(Example) The present invention will be described below with reference to the illustrated embodiments.

Continuous underground walls (1) that also serve as support piles are constructed around the outer periphery of the underground structure, and support pillars (2) for suspending PC beams (described later) are erected and the first root cutting is performed. In the figure (3
) is the bottom of the first uprooting. (See Figure 1) The underground continuous wall (1) shall have pillar and beam-shaped built-in structures as necessary. In addition, if the basement floor construction is to be carried out at the same time as the above-ground structure work in order to shorten the construction period, strong support pillars will be used to support the upper structure. Furthermore, depending on the hardness or softness of the ground, concrete for working is placed at the bottom of the root cutting (3).

Note that the underground continuous wall (1) and the support pillar (2) constitute the above-mentioned vertical member.

Next, between each of the vertical members, PC beams (4) corresponding to the number of underground floors are superimposed on the cutting bottom (3), and the PC beams (4) of the construction work floor (generally the floor beam of the first floor) are superimposed on the root cutting bottom (3). 5) between the supporting pillars (2), and a suspension frame for hanging the PC beam (
6) Install. Furthermore, formwork decks for floor attachment (force etc. are attached to the PC beams (5) and slab concrete is cast. (See Figure 2) Set it up.

The formwork deck (7) is suspended by a hanging frame (6) as described later.

FIG. 7 and FIG. 8 show details of the hanging frame (6),
At the point where the PC beams (5) on the first floor intersect, between each adjacent side of a rectangular frame-shaped hanging frame (@) that intersects the axis of each PC beam (5) at an angle of 45°, A PC beam support member (60) mounted perpendicularly on the PG beam (5) is connected, and between the opposite sides of the hanging frame (6a) there is a A pair of connecting pieces (6c) facing each other with the direct column (2) in between are connected, and a pair of connecting pieces (6c) sandwiching the true pillar (2) are further connected between each of the connecting pieces (60). ,
Each of the connecting pieces (6C) (6d) is equipped with a roller (6e) that moves along the true pillar (2).

In addition, both ends of the PC support beam material (6b) and the hanging frame (6b)
PC strands (pl) for hanging each of the PC beams (4) are inserted through the intersections with a), and the strands (pl) are attached to the lower end of each PC beam (4) with a locking tool ( ql). Further, a PC strand ω2 for hanging a formwork deck is inserted through the center of each side of the hanging frame (6a), and is locked to the formwork deck (force) via a locking tool (g2).

Therefore, by operating each of the strands 1) and ω2), the PC beam (5) and formwork deck (7) are suspended.

In the figure, (4a) and (5a) indicate the PC beams (4) and (5a).
(40) is a connecting steel frame part that is embedded in the PC beam (2a) and protrudes from the end of the beam so as to be connected to the bracket (2a) that is embedded in the PC beam (2a) and protrudes from the outer periphery of the PC beam (2a). This is the protruding end of the rib cage embedded in 4).

Next, the PC beam (4) on the first root cutting bottom (3) is connected to the PC strand (1) by the suspension frame (6).
The tree is then hoisted up through the pipe and a second round of root cutting is carried out. (8) is the bottom of the second round of root cutting. (See Figure 3) Next, the lower floor PC beam (4) is superimposed by the suspension frame (6).
), and hang the PC beam (4A) at the top of the same PC beam (4) for one underground place between the true pillars (2) and the underground continuous wall (1).
and the true pillar (2), and then the slab formwork deck (7A) for the first basement floor is fixed using the hanging frame (6).
Suspend it on the PC beam (4) for one underground location. (See Figure 4) Next, concrete slab (9) for the first basement floor was poured.
The third round of root cutting will be carried out. In the figure, 11α is the bottom of the third cutting. Next, the PCs on the second stage and below are mounted on the suspension stand (6).
Suspend the beam (4) and attach it to the PC beam (4) for the second basement floor.
B) is fixed between the true pillar (2), the underground continuous wall (1) and the true pillar (2), and then the slab formwork deck for the second underground floor (7B) is installed using the suspension frame (6). The PC beam (4B
) above (see Figure 5), and pour the slab concrete ') -) (9) on the second basement floor, and repeat the same process as above for the required basement floors, and as shown in Figure 6, the final After cutting the roots and pouring the foundation concrete a't on the bottom circle of the final root cutting, the post-casting column body a9 construction and splicing treatment are performed to complete the entire process.

(Effects of the Invention) As described above, according to the present invention, vertical members are constructed in the ground, and a required number of PC beams are overlapped and suspended in a descending manner between the members, and as the root cutting progresses, the vertical members are constructed underground. PC of the above required number of stages
The beams are suspended, and from the top, the first basement floor, the second basement floor...
By fixing between the vertical members at the sections and sequentially constructing the basement floor slabs on the PC beams on each basement floor, underground construction can be carried out rationally using 20 standardized members, simplifying on-site work. This will improve work safety, streamline underground work, and allow above-ground work to be done simultaneously, shortening construction time and reducing construction costs.

[Brief explanation of the drawing]

Figures 1 to 6 are longitudinal cross-sectional views showing the steps of an embodiment of the method for constructing an underground structure according to the present invention, and Figures 7 and 8 are a plan view of a hanging frame and a longitudinal cross-sectional view of the kettle. It is. (1)...Underground continuous wall, (2)...Support pillar, (3
)...First cutting bottom, (4)...PC beam, (5)
... PC beam for construction work floor, (6) ... hanging frame,
(7)...Formwork deck, (8)...Second root cutting bottom, (9)...Slab concrete for the first basement floor, (6)
...Slab concrete on the second basement floor, screaming...The bottom of the third round of root cutting.

Claims (1)

[Claims] After the first root cutting is completed, the required number of PC beams are overlapped and suspended freely between the vertical members constructed underground, and each PC beam is placed at the bottom of the first root cutting. The first stage of PC beams at the top were fixed between the vertical members, and the first floor slab was constructed on top of each of the first stage PC beams, and then the second stage of root cutting was carried out. After that, the PC of the second stage and below
The beam is suspended to the bottom of the second root cutting, the second stage PC beam is fixed between each of the vertical members, and the slab for the first basement floor is constructed on the second stage PC beam, and the following is the same as above. A construction method for underground structures characterized by repeating the process of