JPH05148837A - Slide-down type strut and inverted construction method using the slide-down type strut - Google Patents

Abstract

PURPOSE:To eliminate the need for an auxiliary strut, to conduct underground body work and excavation work simultaneously and to shorten the term of work of ground work by forming a floor body by lowering and installing a strut. CONSTITUTION:A landslide protection wall 3 and structure studs 5 are executed into the ground and primary excavation is performed, a strut fixing bracket installed to the landslide protection wall 3, the structure studs 5, etc., is assembled, and strut mounting work is fixed. Pre-load is applied to the landslide protection wall 3, a working floor is mounted onto struts, and concrete is placed to assembled floor forms, thus forming a floor body. The titled method of construction progresses to a process, in which pre-load is released while conducting secondary excavation and the floor body is lowered and the struts are supported, and a process, in which the strut fixing bracket removed is set up at the next temporary positions of struts. The floor is lowered simultaneously and fixed onto the struts and the struts are brought down and mounted, and the floor forms are removed and processes after the introduction of pre-load are repeated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide-down type cutting girder used for earth retaining work and a reverse striking method capable of shortening the construction period by using the slide-down type cutting girder.

[0002]

2. Description of the Related Art Recently, the reverse construction method, which is known as one of the earth retaining methods, is the first floor → the first basement floor → the second basement floor →
The floor panels on each floor are functioning as supporting works, such as the basement floor.

FIGS. 15 to 20 show a plan view and a cross-sectional view of the construction sequence from the construction of the retaining wall and the construction column to the construction of the first floor floor in the reverse construction method. This conventional construction method is shown in FIG. First, as shown in FIGS. 15 and 16, a mountain retaining wall 3 is formed in the ground 1 to perform mountain retaining, and then, FIG. 17 and FIG.
As shown in FIG. 8, a plurality of structure pillars 5 are driven in the ground 1 as support pillars. In addition, in the figure, 7 is a bottom expansion pile which supports the true column 5.

Next, in order to perform the floor construction on the first floor, the primary excavation is performed to a predetermined depth, and the discarded concrete 11 is placed on the root cutting bottom 9 as shown in FIG.
After constructing the floor formwork 13 on the first floor with the work floor 1 as shown in FIG.
Place concrete on the floor formwork 13 as shown in 0
The concrete is cured until the strength of the floor slab 15 appears.

After curing, discarded concrete 11 and floor formwork 1
3 is dismantled, and further secondary excavation is carried out to perform flooring work on the first basement floor. After secondary excavation, waste concrete is placed at the root cutting bottom again, and this waste concrete is used as a working floor underground. While constructing the floor formwork on the 1st floor, concrete is placed and cured until strength is obtained. At the time of this secondary excavation, the 1st floor floor body 15 functions as a support structure that receives earth pressure. Will be done. Then, as shown in FIG. 21 (A), the same work is repeated as many times as the number of bodies to be reversed, and the excavation work and the underground work are performed with the underground body having the function of supporting work. I will go.

Prior to the final excavation, it has conventionally been necessary to install an auxiliary cutting beam between the lowermost reverse punching body and the root cutting bottom. That is, at the time of final excavation, usually, the floor height from the bottom reverse punched body to the root cutting bottom becomes higher than that at the time of other excavations, and the earth pressure acting on the retaining wall 3 becomes larger when the underground becomes deeper. If this earth pressure is supported only by the bottom-side reverse hitting body and the ground on the receiving side that is deeper than the final root cutting bottom, the cross-section performance of the retaining wall 3 becomes very large and the economical efficiency becomes extremely poor. Here, though not shown, conventionally, an auxiliary cutting beam made of steel or the like has been installed between the body to be reversely punched at the lowest stage and the root cutting bottom as a temporary support work.

In FIG. 20, reference numeral 17 designates temporary openings formed in each subterranean body including the first floor floor body 15, and these temporary openings 17 are used for subsequent excavation and carrying in and out of the body material. Is done.

[0008]

However, in the conventional construction method as described above, since the body that strikes back has the function of supporting work, it is the fact that it is not possible to introduce a preload. The deformation of the mountain retaining wall that occurs during the excavation stage will remain even if the body to be hammered up has the function of supporting work. Further, since the reverse-punched body is a concrete structure, there is a phenomenon in which a large drying shrinkage occurs at the time of initial strength generation after the concrete is placed and the mountain retaining wall is pulled toward the excavation side.

As described above, in the conventional method, problems such as deformation of the retaining wall have been pointed out, and improvement of such points is desired. Further, as described above, in the conventional construction method, since an auxiliary cutting beam is required between the lowermost step reverse punching body and the root cutting bottom, the lowermost step reverse punching body and the root cutting bottom are The excavation between two parts was divided into two parts, and the material of the auxiliary girder was taken in the middle of the excavation, and the auxiliary girder was temporarily installed on the retaining wall. However, the temporary construction of the auxiliary girder is very troublesome and the construction period is prolonged. It is a cause.

Furthermore, since the conventional construction method proceeds as shown in FIG. 21 (A) in the order of excavation → reverse striking body → excavation → reverse striking body, the underground construction is carried out. Moreover, the body-related occupations were interrupted many times, and even though the construction period was required to be shortened, these continuous operations were not possible and it was very inefficient.

The present invention has been devised in view of the above-mentioned circumstances, and simultaneously carries out underground body work and excavation work, and
It is an object of the present invention to provide a reverse striking method in which the construction period of underground work is shortened by eliminating the temporary construction of an auxiliary truss, and a slide-down type strut used in this reverse striking method.

[0012]

In order to achieve such an object, a slide-down type cutting girder according to the present invention is a cutting girder for supporting an abdomen that presses down a mountain retaining wall. A plurality of cross-beam crossing pieces formed in a shape, a plurality of cross-beam pieces connected in a grid pattern through these cross-beam crossing pieces, a connecting portion between the cross-beam crossing piece and the cross-beam piece, or The pre-load jack is attached to the connecting portion between the cross beam pieces, and the cross beam cross piece can be suspended by the elevating means.

Further, according to the reverse construction method of the present invention utilizing the slide-down type girder, a mountain retaining wall construction step for forming a mountain retaining wall in the ground to retain the excavated ground, and a true pillar in the excavated ground. The structure pillar construction process to drive in, the primary excavation process to carry out the primary excavation to perform the floor slab construction on the first floor, and the above-mentioned structure pillar and the mountain retaining wall with the mounting brackets for fixing the cutting beams. A girder mounting process of assembling and fixing a slide-down type girder to a bracket, a pre-load introducing process of pre-loading a mountain retaining wall with a pre-load jack attached to the slide-down type girder, and a work floor on the slide-down type girder Floor installation process for installing the floor formwork, floor formwork construction process for assembling the floor formwork on the work floor, and concrete placement and curing for placing concrete on the floor formwork and then curing the concrete. After the curing, the secondary excavation process in which the secondary excavation is performed to perform the floor slab construction on the first basement floor, and the secondary excavation is performed. After supporting the cutting beam supporting step for supporting the sliding down type cutting beam, the above cutting beam fixing bracket to which the sliding down type cutting beam is attached is suspended, and the sliding down type cutting beam is suspended by the elevating means. Bracket mounting position changing process for mounting at a temporary position and sliding beam of the slide down type cutting beam by the elevating means to fix the sliding down type cutting beam on the cutting beam fixing bracket mounted at the cutting beam temporary position And a mounting step, and after the above steps are completed, the steps after the preload introducing step are sequentially repeated.

[0014]

According to the slide-down type girder and the reverse striking method using the slide-down type girder according to the present invention, when the preload jack mounted on the slide-down type girder preloads the mountain retaining wall, the slide-down is performed. The slide-down type girder suppresses the force of pulling the mountain retaining wall toward the excavation side due to the drying shrinkage of concrete, as well as the type girder pushes the mountain retaining wall back to the ground side.

Further, after the strength of the lowermost floor slab is obtained, the slide-down type girder can be slid down to a required position, and this slide-down type girder functions as a girder that can be replaced with a conventional auxiliary girder. To do.

Further, according to the present invention, by sliding down the slide-down type girder by the elevating means, the slide-down type girder functions as a work floor and a support work for the underground body construction. ..

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. The same parts as those in the conventional example shown in FIG. 15 and subsequent figures are designated by the same reference numerals.

FIG. 1 is a plan view of a slide-down type cutting girder 21 according to an embodiment of the present invention. This slide-down type cutting girder 21 is, like a conventional cutting girder, mounted on a mountain retaining wall 3. It supports 23 and is a slide-down type girder 2
1 is a plurality of cross beam crossing piece 2 formed in a cross shape
5 and the cross beam pieces 27, 29, 31 and 33 connected in a grid pattern through the cross beam intersection pieces 25, and the connecting portions of the cross beam piece 29 and the cut beam piece 31, respectively. It is composed of a preload jack 35 and a plurality of flints 37 erected from the beam member 29 and erected upright. In addition, each of the above-mentioned beam members 27, 29, 3
1, 33 and flint 37 are conventional beam materials made of H-shaped steel, and the structure of the preload jack 35 itself and its mounting structure are completely the same as those known.

The cross-beam crossing piece 25 has a cross-shaped structure in which H-shaped steels are crossed as shown in FIG. 2, and a large number of bolt holes 41 are formed in the flange 39a of each connecting arm 39 extending in all directions. Has been formed. Also, each connecting arm part 3
A flat contact surface 43 having a plurality of bolt holes 41 formed therein is formed at the end of 9 similarly to the ends of the beam members 27, 29, 31, 33. For example, as shown in FIG. 3, the contact surface 45 of the truss beam piece 27 is bolted, and the truss beam piece 27 is bolted to the truss crossing piece 25 via the plate 47.

Further, as shown in FIG. 4, a rod insertion hole 49 is coaxially formed in the central portion of the beam crossing piece 25. Then, a reinforcing square pole portion 51 is formed of a steel plate 53 having the same thickness as the flange 39a so as to surround the rod insertion hole 49, and further, a reinforcing steel plate 53 is used for reinforcement so as to surround the square pole 51. A square pole portion 55 is formed. The flange 39a of the cross beam intersection piece 25 is provided.
The web 39b is made up of beam pieces 27, 29, 31, 33.
The strength is secured by making the wall thickness twice as much as

Then, in the rod insertion hole 49, as shown in FIG.
As described above, the step rod 57 is attached by the nut 59 and the washer 61. This step rod 57
As shown in FIG. 5, it is attached to a slide-down jack 63 such as a well-known center hole type jack arranged on the floor body 15 on the first floor, and by the operation of the slide-down jack 63, as will be described later. The slide-down type cutting beam 27 slides down.

Thus, the slide-down type girder 21 according to this embodiment has the girder intersection piece 2 constructed as described above.
As shown in FIG. 1, the five columns 5 are arranged at equal intervals around the nine vertical columns 5 driven in at regular intervals, and are connected to each other by the cross beam pieces 33. The connecting arm portions 39 of the cut beam crossing piece 25 are connected by the cut beam pieces 27 along the mountain retaining wall 3, and the connecting arm portions facing the mountain retaining wall 3 of the crossing beam intersecting piece 25 are formed. 39
The beam members 29 and 31 are connected to each other, and the ends of the beam member 29 are agitated to abut against the beam member 23.

Further, as described above, the well-known preload jack 35 is mounted on the connecting portion between the cut beam piece 29 and the cut beam piece 31, and after the slide-down type cut beam 21 is assembled, this preload is carried out. The mountain retaining wall 3 can be pushed outward by the jack 35.
As shown in FIG. 6, a jack cover 65 is attached to the mounting position of the preload jack 35 as in the conventional case, and when the preload jack 35 is used, the jack cover 65 can be removed.

Then, as shown in FIG. 5, a truss fixing bracket 67 is detachably attached to each of the true column 5 and the mountain retaining wall 3, and the slide-down truss 21 is assembled on the truss fixing bracket 67. ， It is supposed to be fixed.

A slide-down type girder 21 according to this embodiment.
Is constructed in this way. Next, an embodiment of the method of the present invention using this slide-down type girder 21 will be described. Similar to the conventional construction method shown in FIG. 15 to FIG. 18, first, the earth retaining wall 3 and the structure pillar 5 are constructed and the primary excavation is carried out to a predetermined depth in order to perform the floor construction on the first floor. Process, structural pillar construction process, primary excavation process).

Then, as shown by the broken line in FIG. 8 or 5, the beam-fixing brackets 6 are respectively attached to the true columns 3 and the mountain retaining walls 3.
7 is attached, and as shown in FIGS. 7 and 8, the slide-down type girder 21 is assembled and fixed on the girder fixing bracket 67 by the above-described procedure, and its end is provided on the mountain retaining wall 3. It is brought into contact with the uprights 23 (cut beam mounting step).

Next, as shown in FIG. 8, the hydraulic unit 69 arranged on the ground is operated to operate the slide-down girder 21.
After preloading the mountain retaining wall 3 with each of the preload jacks 35 attached to and pushing back the mountain retaining wall 3 to the natural side (preload introducing step), as shown in FIG. 9 and FIG. Assemble a working floor 71 for construction of the first floor floor as a mount, and mark out 7
Perform 3 (work floor installation process).

Then, as shown in FIG. 10, a floor form 75 is assembled on the work floor 71 (form work process), and the floor form 75 is assembled.
After concrete is poured into the concrete, the concrete is cured (concrete pouring, curing process) to form the floor slab 15 on the first floor. Also, as shown in FIG. 12, secondary excavation is performed using the temporary opening 17 provided in the floor slab 15 (secondary excavation step). Then, after performing secondary excavation, the preload of the slide-down type girder 21 is released and the slide-down type girder 21 is separated from the mountain retaining wall 3.

Next, a plurality of slide-down jacks 63 are installed at predetermined positions on the floor body 15 on the first floor, and the step rod 5 extending from the slide-down jacks 63 is installed.
7 is inserted into the rod insertion hole 49 of the predetermined cut beam intersection piece 25 with the bolt 59 and the washer 61 as shown in FIGS. 3 and 5, and is arranged corresponding to the peripheral portion of the slide down type cut beam 21. The step rod 57 of the slide-down jack 63 is connected to the peripheral portion of the slide-down type cutting beam 21, and the slide-down type cutting beam 21 is supported by the step rod 57 (cut beam supporting step).

Thus, the slide-down type girder 21 is thus provided.
After the secondary excavation is completed by supporting the step rod 57 with the step rod 57, the cutting beam fixing bracket 67 is removed and attached to the next cutting beam installation position as shown in FIG. 12 (bracket mounting position changing step). By removing the fixing bracket 67, the slide-down type girder 21 is suspended by the step rod 57.

Then, jacks 63 for each slide down
The slide down type girder 21 is slid down by centralized control, and the floor form 75 is removed when the slide down type girder 21 is slid down to some extent and placed on the work floor 71 on the slide down type girder 21. Thereafter, as shown in FIG. 13, the slide-down type girder 21 is fixed on the girder fixing bracket 67 attached to the girder temporary position (downward mounting step).

After completion of these steps, the steps below the preloading step are sequentially repeated to form an underground body, and the slide-down girder 2 is formed.
No. 1 will function as a support work that replaces the conventional underground body. Then, after the strength of the lowermost floor body is obtained, if the slide-down type girder 21 is slid down to a required position, this slide-down type girder 21 functions as a girder that can be replaced with a conventional auxiliary girder. It will be.

As described above, in this embodiment, the preload jack 35 attached to the slide-down type girder 21 preloads the mountain retaining wall 3 to push the mountain retaining wall 3 back to the natural ground side, and then strikes the body for reverse hammering. Since the slide-down type girder 21 suppresses the force of pulling the retaining wall 3 toward the excavation side due to the drying shrinkage of the concrete, the reverse construction method according to the present embodiment provides a conventional construction method. In comparison, the deformation of the mountain retaining wall 3 can be reduced.

Further, according to this embodiment, after the strength of the lowermost floor slab is obtained, the slide-down type girder 21 is slid down to a required position, and the slide-down type girder 21 is moved.
Since it functions as a cutting girder that replaces the conventional auxiliary cutting girder,
There is no need to newly install auxiliary beams.

Furthermore, according to the present embodiment, the slide-down type girder 21 is used as a working floor for underground construction and a support work, so that excavation work and underground work can be performed as shown in FIG. 21 (B). Since the physical work can be done in parallel, the construction period of the underground work can be shortened compared with the conventional construction method in combination with the fact that it is not necessary to newly install an auxiliary girder.

Further, as shown in FIG. 14, a conventional cutting beam 71 is used.
Although the beam members 71a, 71b, 71c are arranged in the upper and lower two stages in the X, Y, Z directions, the sliding down type beam 21 according to the embodiment of the present invention shown in FIG. Since the beam pieces 27, 29, 31, 33 are connected and arranged on the same plane by using the piece 25, it is easy to install the work floor 71 for underground construction by using this as a support stand. Have.

In the above embodiment, the slide-down jack 63 is used to slide down the slide-down girder 21, but the slide-down girder 2 is used.
The lifting / lowering unit 1 is not limited to such a device, and other known devices such as a VSL lifting device may be used.

[0038]

As described above, according to the slide-down type girder according to the present invention, it is possible to arrange and connect the respective girder pieces on the same plane. It has an advantage that a work floor for body construction can be easily installed.

Further, according to the reverse construction method according to the present invention, the deformation of the mountain retaining wall can be made smaller than that of the conventional construction method, and the slide-down type cutting can be performed after the strength of the bottom floor floor body has been obtained. Since the beam can be slid down to the required position and this slide-down type cutting girder can function as a cutting girder replacing the conventional auxiliary cutting girder, it is not necessary to newly install the auxiliary cutting girder.

Furthermore, according to the reverse construction method of the present invention, the slide-down type girder can be used as a work floor and a support work for the underground body construction, so that excavation work and underground body work can be performed in parallel. In combination with the fact that there is no need to install auxiliary beams, it has become possible to shorten the construction period for underground construction.

[Brief description of drawings]

FIG. 1 is a plan view of a slide-down type girder according to an embodiment of the present invention.

FIG. 2 is a perspective view of a beam crossing piece.

FIG. 3 is a cross-sectional view of a cross beam intersection piece and a connecting portion of the cross beam piece.

FIG. 4 is a central plan view of a cross beam intersection piece.

FIG. 5 is a side view showing a state in which a slide-down type girder is supported by a step rod of a slide-down jack.

FIG. 6 is a perspective view of a preload jack mounting portion.

FIG. 7 is a plan view of a slide-down type cutting beam in a cutting beam mounting step.

FIG. 8 is a cross-sectional view showing a preload introducing step.

FIG. 9 is a plan view of a work floor on which marking has been performed.

FIG. 10 is a cross-sectional view showing a formwork construction process.

FIG. 11 is a plan view showing a secondary excavation process.

FIG. 12 is a cross-sectional view showing a state where a slide-down type girder is suspended by a step rod.

FIG. 13 is a sectional view showing a descending mounting step of the slide-down type girder.

FIG. 14 is a partial perspective view of a conventional girder.

FIG. 15 is a plan view of a mountain retaining wall construction process.

FIG. 16 is a cross-sectional view of a mountain retaining wall construction process.

FIG. 17 is a plan view of a true pillar construction process.

FIG. 18 is a cross-sectional view of a construction pillar construction process.

FIG. 19 is a cross-sectional view showing a state in which concrete is poured into the floor formwork to form a floor deck.

FIG. 20 is a plan view of the first floor floor body.

FIG. 21 is an explanatory diagram showing a construction order of the reverse construction method and the conventional construction method according to the present invention.

[Explanation of symbols]

 1 Ground 3 Mountain retaining wall 5 Structural column 17 Temporary opening 17 Temporary opening 21 Sliding down type girder 23 Raised 25 Girder intersection piece 27, 29, 31, 33 Girder piece 35 Preload jack 63 Sliding down jack 67 Girder fixing bracket

Front page continuation (72) Masao Maruoka Inventor Masao Maruoka 3-18 No. 18-18, Mitsudori, Mihara-machi, Minamikawachi-gun, Osaka Takenaka Corporation Technical Research Institute Osaka Branch

Claims (2)

[Claims] 1. A cut beam for supporting an abdomen that presses down a mountain retaining wall, the cut beam being provided with a plurality of cross beam cross piece pieces formed in a cross shape, and the cut beam cross piece pieces. A plurality of cutting beam pieces connected in a grid pattern, and a preload jack attached to a connecting portion between the cutting beam intersection piece and the cutting beam piece or a connecting portion between the cutting beam pieces, and the cutting beam A slide-down type girder characterized in that the intersection piece can be suspended by elevating means. 2. A earth retaining wall construction process for forming a earth retaining wall in the ground to earth excavate the earth, a construction pillar construction process for driving a construction pillar into the excavation ground, and a floor covering construction on the first floor. In order to perform the primary excavation, the primary excavation process, and the beam-mounting process for attaching and fixing the beam-fixing bracket to the above-mentioned structure column and the mountain retaining wall, and assembling and fixing the slide-down type beam to this beam-fixing bracket. , The preload introduction process of preloading the retaining wall with the preload jack attached to the slide down type beam, the work floor setting process of installing the work floor on the slide down type beam, and the floor formwork is assembled on the work floor. Floor formwork construction process, after placing concrete on this floor formwork, concrete pouring to cure concrete, curing process, and secondary digging to perform floor slab construction on the first basement floor after curing The secondary excavation step for performing the secondary excavation, the cutting beam supporting step for releasing the preload and performing the secondary excavation to support the slide-down type cutting beam by the elevating means, and the above-mentioned cutting beam fixing bracket to which the slide-down type cutting beam is attached And suspend the slide-down type girder by the elevating means, then change the bracket mounting position to attach the removed girder fixing bracket to the next temporary position of the girder, and the slide-down type girder with the elevating means. It consists of the steps of descending and mounting the sliding girder that fixes the sliding down type mounting girder on the mounting girder fixing bracket that slides down and is installed at the mounting girder temporary position. Reverse construction method characterized by sequentially repeating the steps of.