JPH0730564B2 - Construction method of underground structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to the underground construction method for construction of underground structures, especially for the soft ground, large scale, and deep underground where the reverse construction method is required. It relates to the construction method of structures.

(Prior Art) In a general construction method for an underground structure, temporary shoring is installed on a temporary earth retaining wall, and a temporary pier is installed to perform underground excavation.

However, for large-scale and deep underground excavation on soft ground, it is difficult to construct with the conventional temporary general mountain retaining method, and in many cases the whole building reverse driving method is adopted to ensure safety. In the reverse construction method, for each basement floor construction work, side frames were assembled on site, reinforcing bars were laid and concrete was placed each time.

(Problems to be solved by the invention) As described above, in the conventional construction method, as for each substructure work of the underground part, the on-site casting form is assembled, the bar arrangement and the concrete placement are performed each time. Support is unstable, and if the strength of the upper floor concrete does not exceed a certain limit, dismantling and lower level root cutting cannot be performed.Furthermore, the demolished formwork material is once transported to the upper floor, tidyed up, and after root cutting. The work of moving to the lower floor again is complicated.

As a result, the reverse striking work is extremely troublesome, the construction cost is high, and the process is delayed.

(Means for Solving Problems) The present invention has been proposed to solve such problems, and the entire basement floor is provided at the first root cutting bottom between vertical true pillars constructed underground. Temporarily place the PC beams, hang all the PC beams by using the suspension frame mounted on the vertical true columns as a reaction force, fix the first floor PC beams between the vertical true columns, and then hang the slab formwork. The pedestal is used as a support material between the first-floor PC beams, the first-floor concrete is placed, the slab formwork is peeled off after hardening of the placed concrete, and the lower-level PC beams and slab formwork are suspended separately. The present invention relates to a construction method for an underground structure, which is characterized by sequentially constructing a basement floor PC beam and a slab by reversing the above steps.

(Operation) In the present invention, as described above, after constructing the supporting true pillars in the ground, the first root cutting is performed, and all the basement floors are formed at the first root cutting bottom between the vertical true pillars. The PC beam is temporarily placed, and all the PC beams are hoisted by using the suspension frame erected on the vertical true pillar as a reaction force support material. It is fixed to each vertical true pillar, slab formwork is erected on the PC beam of the same step, and the first floor concrete is placed.
After hardening of the cast concrete, the slab formwork is peeled off and the PC beam and slab formwork on the lower floor are hung separately.

After the construction of the slab on the first floor above the ground is completed, the second
Of the PC beams in the same superposed state, the following root cutting was carried out, and the PC beams of the second stage and below located below the first stage PC beams were suspended in the state of being piled up to the second root cutting bottom. After fixing the second-stage PC beam located at the top between the vertical columns, a slab on the first basement floor was constructed on the second-stage PC beam in the same manner as above, and the same as above. Underground structures are constructed by repeating the steps for the required floors.

(Examples) The present invention will be described below with reference to illustrated examples.

A continuous underground wall (1) that also serves as a support pile will be constructed on the outer periphery of the underground structure, and a supporting true pillar (2) will be planted for hanging the PC beam, which will be described later, for the first root cutting. (3) in the figure
Is the first root cutting bottom. (See FIG. 1) In addition, a pillar type and a beam type are incorporated in the underground continuous wall (1) as needed. Further, concrete for working soil is placed on the root cutting bottom (3) due to the hardness of the ground.

Next, between the above vertical true pillars, PC beams (4) corresponding to the number of basements are temporarily placed on the root-cutting bottom (3), and PCs for the work floors requiring construction (generally floor beams) The beam (5) is installed between the supporting true pillars (2), and the suspension frame (6) for hanging the PC beam and the form deck is installed. Further, the floor forming required formwork deck (7) and the like are attached to the suspension frame via wires at the same level as the upper end of the PC beam, and slab concrete is poured. (See Fig. 2) At this time, use holes for excavation and building work at appropriate places.

The formwork ditch (7) is hung by the suspension frame (6) as described later.

7 and 8 show the details of the suspension frame (6),
At the location where the PC beams (5) on the first floor intersect, between the adjacent sides of the rectangular frame-shaped suspension frame (6a) that intersects with the axis of each PC beam (5) at an angle of 45 °, A PC beam receiving member (g ₁ ) which is supported orthogonally to the PC beam (5) is connected under the PC beam (5), and is orthogonal between the opposite sides of the suspending member (6a) and is directly connected to the supporting line A pair of connecting pieces (6c) facing each other across the pillar (2)
And a pair of connecting pieces (6d) sandwiching the true pillar (2) are further connected between the connecting pieces (6c), and the supporting true pillars are connected to the connecting pieces (6c) (6d). (2) A restricting piece (6e) that is in contact with the corner and restricts the horizontal position of the hanging frame is attached.

Both ends of the PC beam member (g ₁ ) and the suspension frame (6e)
PCs for hanging the PC beams (4) at the intersections with
The strand (p ₁ ) is inserted, and the strand (p ₁ ) is locked to the lower end of each PC beam (4) via a locking tool (q ₁ ). Further, a PC strand (p ₂ ) for suspending the formwork deck is inserted through the center of each side of the suspension frame (6a) and locked to the formwork deck (7) via a locking tool (q ₂ ). Has been done.

Therefore, by operating the strands (p ₁ ) and (p ₂ ), the PC beam (5) and the form deck (7) can be hung separately.

In the figure, (4a) and (5a) are embedded in the PC beams (4) and (5), and the brackets (2) projecting from the outer periphery of the true column (2).
The connecting steel frame projecting from the beam end so as to be joined to a), (4b) is the projecting end of the rib that is embedded in the PC beam (4).

Next, the PC beam (4) on the first root cutting bottom (3) is lifted by the suspension base (6) through the PC strand (p ₁ ) to perform the second root cutting. (8) is the second
It is the next root cut. (See FIG. 3) Then, for the lower floor, which was polymerized by the suspension frame (6).
Suspend the PC beam (4), among the PC beam (4), the uppermost PC beam (4A) for the first basement floor between the vertical true pillars (2) and between the underground continuous wall (1) and the vertical true pillar It is fixed to (2), and then the slab formwork deck (7) is hung up on the PC beam (4A) for the first basement floor by the suspension frame (6). (Refer to Fig. 4) Slab concrete (9) on the first basement floor is placed in pairs and the third root cutting is performed. (10) in the figure is the third root cutting bottom. PC beams (4) below the second stage are hung by a suspension frame (6) in pairs, and the PC beams (2) for the second basement floor of the second stage are connected between the vertical columns (2) or the underground wall. It is fixed between (1) and the vertical true pillar (2), and then the suspension frame (6).
Suspend the slab formwork deck (7) on the PC beam (4B) and place the slab concrete (9 ') on the second basement floor (see Fig. 5). After overturning, the final root cutting is performed as shown in Fig. 6, and the basic concrete (12) is placed on the final root cutting bottom (11), and then the post strut body (13) construction and jointing treatment. Go to
Complete all steps.

(Effects of the Invention) According to the present invention, the construction of the underground portion is performed by the suspension frame mounted on the vertical true pillar, and the portion above the suspension frame of the vertical true pillar is used for the construction of the steel frame on the upper floor. Therefore, the above-ground part and the underground part are simultaneously constructed, and the workability is improved in combination with the fact that the suspension base can be used for both the PC beam and the slab formwork.

[Brief description of drawings]

1 to 6 are vertical cross-sectional views showing the steps of an embodiment of a method for constructing an underground structure according to the present invention, and FIGS. 7 and 8 are plan views and vertical cross-sectional views of a suspension frame, respectively. Is. (1) …… Continuous underground wall, (2) …… Supporting true pillar, (3)…
… Primary deforestation bottom, (4) …… PC beams, (5) …… PC floor beams for construction work, (6) …… Suspended frame, (7) …… Formwork deck, (8) …… The second root cut bottom, (9) …… Slab concrete on the first basement floor, (9 ′) …… Slab concrete on the second basement floor, (10) …… Third root cut bottom.

Claims (1)

[Claims] [Claim 1] All the PC beams of the basement floor are temporarily placed on the first root cutting bottom between the vertical true pillars constructed in the ground, and the suspension frame mounted on the vertical true pillars is supported by reaction force. Hoist all PC beams as materials, 1
After fixing the floor PC beam between the vertical true pillars, the slab formwork is installed between the first floor PC beams using the suspension frame as a supporting material, the first floor concrete is cast, and the slab after hardening of the cast concrete is slab A construction method for an underground structure, characterized in that the formwork is peeled off, the PC beam and the slab formwork on the lower floor are hung separately, and then the above steps are repeated to successively construct the PC beam and the slab on the basement floor.