JP2001336164A - Working platform for constructing underground structure and constructing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working platform and the constructing method thereof which facilitates ingress and egress of haulage vehicles for carrying out excavated soil of a ground surrounded by earth retaining walls and by which an underground structure can be efficiently constructed and hence, the construction period can be reduced when the underground structure of a building is constructed in a narrow building site. SOLUTION: After a building site surrounded by earth retaining walls is primarily excavated relatively shallowly, working platforms are continuously connected to each other so that one end edge facing a road side is almost flush with the road and the primarily excavated excavation recess is opened between other end edge and the earth retaining wall. Haulage vehicles are allowed to come in and out on the working platform from the road side and soil secondarily excavated by excavating machine on the working platform is carried out and after the secondary excavation, the working platform is used as a part of slabs above the ground to construct the underground structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground used as a work space of an excavating machine for excavating the ground and a transport passage for excavated earth and sand when building an underground structure of a building in a narrow land such as an urban area. The present invention relates to a work gantry for building a structure and a method of building the work gantry.

[0002]

2. Description of the Related Art Conventionally, when a building having a relatively shallow underground structure is constructed, first, as shown in FIG. 9, a ground is attached to the ground around an underground structure 11 constituting the first basement floor of the building to be constructed. After constructing the wall 12, the ground surrounded by the retaining wall 12 is excavated to a depth corresponding to the height of the underground structure 11, and the foundation 14 is built on the bottom surface of the excavation recess 13,
The underground structure 11 is constructed by sequentially constructing the pillars and walls 15 and the slab 16 on the first floor from the base 14 upward, and then the ground floor is constructed.

[0003] The underground structure 11 in such a building
When constructing a building, if there is an existing building around the building to be constructed and there is almost no work space for excavating the ground surrounded by the retaining wall 12, first, A temporary work gantry 17 is laid inside, and the ground below the work gantry 17 is excavated to a depth corresponding to the height of the underground structure 11 to be constructed, and the excavated soil is waiting on the work gantry 17 At present, the underground structure 11 is constructed as described above after being mounted on the transport vehicle 18 and carried out and excavated to a predetermined depth.

[0004]

However, usually,
Since the underground structure 11 is constructed so that the above-mentioned slab 16 at the upper end of the underground structure 11 matches the height of the ground surface, the temporary work gantry 17 is previously set at about 50 cm higher than the slab 16, Therefore, in order to get a vehicle such as a truck on the work gantry 17 from the road 19 around the building, the end of the work gantry 17 facing the road is shown in FIG. Passageway inclined downward toward the road side
17a, and because the underground structure 11 to be built is very close to the position just below the boundary with the road 19, this passage 17a becomes steep and the vehicle enters and exits. Not only does this cause a problem, but also the lower surface of the passage 17a is close to the corner of the slab 16 of the underground structure 11 to be built, making it difficult to construct the end of the slab 16. Passage 17a
If the slope is made gentler, the construction of the slab 16 becomes easier. However, if this is done, the passage 17a becomes longer and protrudes onto the road 19, so that the passage 17a cannot be arranged.

[0005] In the site of the building to be constructed,
Since the temporary work gantry 17 is provided,
In addition to the cost of the work gantry itself, the laying cost and the laying work are required, and furthermore, the removal work after the construction of the underground structure 11 has to be carried out. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to use a part of a ground floor slab as a work gantry without employing a temporary work gantry. It is an object of the present invention to provide a work gantry for underground structures and a method of constructing the underground structures capable of smoothly entering and exiting the building, improving work efficiency, and economically constructing underground structures.

[0007]

In order to achieve the above-mentioned object, a work gantry for constructing an underground structure according to the present invention is provided in an underground structure surrounded by a retaining wall. A part of the ground floor slab supported by these piles is installed on a plurality of piles that are cast deeper than the bottom of the underground structure to be constructed Then, a work gantry is formed by a part of the ground floor slab, and a part of the outer peripheral end of the work gantry is formed to be continuous with the ground surface in substantially the same horizontal plane.

In the work gantry for constructing an underground structure,
According to a second aspect of the present invention, an end surface of the outer peripheral end other than the one end and the upper end of the retaining wall connected to the ground surface of the work gantry on the substantially same horizontal plane are connected by a cutting beam member. The invention according to claim 3 is characterized in that a beam part integrally provided on the lower surface of the work gantry is supported on an upper end of the pile body. Further, the invention according to claim 4 is characterized in that the work gantry is formed by a plurality of precast concrete plates.

According to a fifth aspect of the present invention, there is provided a method of constructing a work gantry for constructing an underground structure, wherein a mountain retaining wall is constructed on a ground around an underground structure to be constructed and is surrounded by the mountain retaining wall. Placing a plurality of piles deeper than the bottom of the underground structure on the ground, and after first excavating the ground surrounded by the retaining wall, the pile is supported at the upper end of the pile and the outer peripheral end thereof A part of the ground floor slab is constructed so that a part of the ground floor is continuous with the ground surface in substantially the same horizontal plane, and a work gantry is formed by a part of the ground floor slab. And

In the method for constructing a work gantry for constructing an underground structure, the invention according to claim 6 is characterized in that after forming the work gantry,
The invention according to claim 7, wherein an outer peripheral end surface of a portion other than a part of the outer peripheral end portion of the work gantry and an upper end portion of the retaining wall are connected by a cutting beam member. Afterwards, secondary excavation is performed to a depth corresponding to the height of the underground structure to be constructed below and around the work gantry, a foundation of the underground structure is constructed on the bottom surface of the excavation recess, and columns of the underground structure are formed. And a ground-floor slab using a part of the wall and the work gantry.

Further, according to the present invention, when the height of the work gantry formed by a part of the ground floor slab is shifted from the height of the ground floor slab to be constructed, It is characterized in that the deviation is corrected.

[0012]

According to the first aspect of the present invention, the ground floor slab supported by the piles on a plurality of piles cast deeper than the bottom of the underground structure to be constructed. Since the work gantry is formed by part of this ground floor slab by constructing a part, the work gantry is firmly and stably supported by the piles, so the work on the work gantry is safe. Of course, a part of the outer edge of this work gantry is continuous with the ground surface on almost the same horizontal plane, so that the underground structure to be built is located on the road around the building. Even if it is close to the road, it becomes easy for a transport vehicle or the like to enter the work gantry or to enter the road from the work gantry through a part of the outer peripheral end that is continuous on the same horizontal plane with the road.

Further, since the work gantry is composed of a ceiling slab of an underground structure to be constructed, that is, a part of the floor slab on the first floor above the ground, the work of laying a temporary work gantry as in the prior art is unnecessary. Not only is it economical, but also the work efficiency is improved and the construction period of underground structures can be shortened.
In addition, the outer peripheral end of the work gantry other than the portion continuous to the ground surface is located at a position separated from the ground retaining wall constructed on the ground around the underground structure to be built within the site, and The primary excavation can be performed smoothly on the ground surrounded by the retaining wall by the excavating machine.

At the time of the primary excavation, since the end face of the outer peripheral end of the work gantry other than the passage side and the upper end of the retaining wall are connected by a cutting beam member as described in claim 2, the retaining It is possible to reliably prevent the wall from tilting inward due to the surrounding earth pressure through the work gantry, to ensure the safety of work such as excavation work, and to make the work gantry a cutting beam member. Since it is used as a part of the construction, it is possible to reduce the number of constructions of the cutting beam member and shorten the construction period.

According to the third aspect of the present invention, since the beam portion integrally provided on the lower surface of the work gantry is supported at the upper end of the pile, the structure for supporting the work gantry by the pile is further enhanced. Not only will it be strong, but it will also be possible to efficiently construct pillars that will be used as pillars for underground structures to be built and integrated with beams.

According to the fourth aspect of the present invention, since the work gantry is formed of a plurality of precast concrete plates, the work gantry can be constructed more efficiently and the work gantry can be mounted on a slab. The workability of the ground floor slab of the underground structure as a part is also improved, and the construction period can be shortened.

According to a fifth aspect of the present invention, there is provided a method of constructing a work gantry, comprising: constructing a mountain retaining wall on the ground surrounding an underground structure to be constructed, and constructing a bottom portion of the underground structure on the ground surrounded by the mountain retaining wall. A step of placing a plurality of piles deeper than deeper, and after first excavating the ground surrounded by the retaining wall, the pile is supported by the upper end of the pile and a part of the outer peripheral end thereof is substantially on the ground surface. A part of the ground floor slab is constructed so as to be continuous on the same horizontal plane and a work gantry is formed by a part of the ground floor slab. Since the primary excavation of the ground only needs to be excavated to a relatively shallow depth where the work gantry can be constructed, the excavation work and the removal of the excavated soil by the transport vehicle can be performed without providing a temporary work gantry, and the primary excavation can be efficiently performed. .

After the primary excavation, a part of the ground floor slab is previously constructed on a plurality of piles cast in the site of the underground structure to be constructed to form a work gantry. From this, the work gantry can be easily constructed using the excavated bottom surface that has been primarily excavated as a scaffold, and the plurality of piles are cast deeper than the bottom of the underground structure to be constructed. Thus, a stable work gantry firmly supported by these piles can be formed.

Further, since a part of the outer peripheral end of the work gantry is directly and horizontally continuous with the ground surface such as a road, the boundary between the underground structure to be constructed and the road is close to each other. Some of these can be used as passages that allow vehicles such as transport vehicles to easily enter and exit, and the work gantry is constructed over the entire ground floor slab of the underground structure to be constructed. The ground is constructed as a part of the ground floor fuzz, so that the first excavated ground is exposed between the outer peripheral end of the work gantry other than the part facing the road and the retaining wall. Through which the secondary excavation of the ground to a depth corresponding to the height of the underground structure to be built by the excavating machine on the work gantry and waiting on the work gantry Of excavated earth and sand into a truck Kill. Secondary excavation of the ground below the work gantry may be performed by an excavating machine moving on the ground.

According to the sixth aspect of the present invention, since the outer peripheral end surface of the work gantry other than a part continuous to the ground surface and the retaining wall are connected by the cutting beam member, a stable and strong underground structure is provided. Since the work gantry for construction can be formed and the work gantry is also used as a cutting beam, it is possible to reduce the number of the cutting beam members to be used, to efficiently perform the cutting beam members, and to remove the work afterwards. Can also be easily performed.

In the method of constructing a work gantry for constructing an underground structure according to the present invention, the height of the underground structure on which the ground below and around the work gantry should be constructed after the work gantry is formed. Secondary excavation to a depth equivalent to the above, constructing the foundation of the underground structure on the bottom of the excavation recess and constructing the ground floor slab partially using the columns and walls of the underground structure and the above work gantry This feature makes it possible to economically and efficiently construct a ground floor slab that uses this work gantry as part of a ground floor slab without removing the work gantry, and supports the work gantry. By using the pile body as a pillar or a wall of an underground structure without removing the pile body, it is economical and the construction period can be further shortened.

According to the seventh aspect of the present invention, after the foundation of the underground structure is constructed, the height of the work gantry formed by a part of the ground floor slab is to be constructed. The feature is that when there is a shift with respect to the height of the ground, the shift is corrected, so that an accurate underground structure can be constructed.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; FIG.
Is a flat rectangular work gantry constructed on the site of the underground structure A to be constructed, and the lower surface thereof is the underground structure A to be constructed.
Is supported by a pile 2 made of a plurality of H-shaped steels which are cast to a depth deeper than the height of the pile. This work gantry 1
Is a part of the ceiling slab of the underground structure A, that is, a part of the floor slab on the first floor above the building where the underground structure A is the first basement. ) Are integrally formed at predetermined intervals. On the other hand, the pile body 2 is cast at the same intervals as the beams 1a of the work gantry 1 in correspondence with these beams 1a, and the upper ends thereof are buried under the lower ends of both sides of each beam 1a. The work gantry 1 is supported in a fixed state.

On the ground near the underground structure A to be constructed in the site, a mountain retaining wall 3 is constructed in a plane rectangular frame shape from the ground surface to the ground deeper than the height of the underground structure A. The work gantry 1 composed of a part of the above-mentioned ground floor slab is configured to firstly excavate the ground B surrounded by the retaining wall 3 relatively shallowly, and then to use the excavated concave portion 4 as a scaffold, as described later, to adjoin the adjacent work gantry. A formwork 8 is assembled between the upper ends of the piles 2 and a part of the ground floor slab is built in advance by casting concrete into the formwork 8 and formed by a part of the ground floor slab. Is what it is.

The area (area) of the work gantry 1 is smaller than the area of the ground B surrounded by the retaining wall 3.
And the upper surface is constructed so as to be substantially on the same horizontal plane as the ground surface, and further, at the four outer peripheral ends of the work gantry 1, a part of the outer peripheral end facing the road C side, that is, one end edge part Is connected to the ground surface above the side wall of the road C in the retaining wall 3 near the boundary G with the road so as to be continuous with the road C. On the other hand, at the four outer peripheral ends of the work gantry 1, other portions other than the above-mentioned one end edge, that is, the other end edge and both side edges are the other ends of the mountain retaining wall 3 facing in parallel with these edges. The upper end portion of the side wall body portion and both side end wall body portions is separated from each other at a predetermined interval, and in the separated portion, the first excavation recess 4 is opened 5 toward the ground surface. ing.

Further, an erection member 6 made of H-shaped steel is attached to the inner peripheral surface on the four sides of the upper end of the retaining wall 3, and the gantry 1 facing this erection member 6 and the opening 5. Are connected to each other by a plurality of cutting members 7 to prevent the retaining wall 3 from tilting inward due to earth pressure around the retaining wall 3. In this case, since the work gantry 1 also serves as a girder member, the number of the girder members 7 to be constructed can be reduced. For example, as shown in FIG. What is necessary is just to make it the structure which connected between the member 7 and the both ends of the longitudinal direction in the both end surfaces of the work gantry 1 and the protruding member 7. In the case where the ground B on which the retaining wall 3 is cast has a large supporting force, it is not always necessary to provide the cutting beams 7.

The work gantry for constructing an underground structure constructed as described above uses the work gantry 1 to perform secondary excavation of the ground for constructing the underground structure A and other operations, and is substantially similar to the road C. A vehicle such as a sediment carry-out vehicle is allowed to enter and exit through a horizontal end connected to the road C side on the same horizontal plane, and the ceiling slab of the underground structure A, that is, the floor slab on the first floor above the ground. When constructing a (ground floor slab), this work gantry 1 is used as a part of the slab, and a slab continuous to the outer peripheral end surface of the work gantry 1 is constructed in the opening 5 to build a ground floor slab. Things. This work gantry 1
Was formed by cast-in-place concrete, but a plurality of precast concrete
It may be formed by installing and laying on top. In this case, the entire ground floor slab including the work gantry 1 as a part is formed of a precast concrete plate.

Next, a method of constructing the work gantry for constructing the underground structure will be described with reference to a construction flowchart shown in FIG.
As shown in FIG. 4, the site of the underground structure A to be constructed is surrounded by an existing building D on three sides, and only the other side faces the side of the road C having the sidewalk C1. In order to construct the underground structure A that is the first basement floor of a high-rise building in such a narrow land, first, a deeper part of the ground around the underground structure A to be constructed in the site than the height of the underground structure A Mountain retaining wall 3
And a plurality of piles for supporting both sides of the lower surface of the work gantry 1 and both sides of the center at a position where the work gantry 1 is to be constructed so as to be continuous with the road C side. 2 is an underground structure A to be constructed as shown in FIGS.
Drill deeper than the bottom.

The pile body 2 is simply driven into the ground B without performing an auxiliary construction method such as ground improvement or the like, thereby reducing the cost. When the ground is an extremely soft ground, a treatment such as simple root winding may be performed.

After the pile body 2 has been driven, the ground B surrounded by the retaining wall 3 is primarily excavated by a drilling machine E such as a backhoe to a relatively shallow depth at which the work gantry 1 can be constructed. Mounted on a transport vehicle F and carried out. In this case, the ground portion B1 facing the road C side is, as shown in FIG.
It is formed on an inclined surface that is inclined upward toward the road C, and the transport vehicle F enters and exits using the inclined surface. Finally, the ground B1 is excavated and removed, thereby removing the retaining wall 3.
An excavation recess 4 formed by primary excavation is provided in a portion surrounded by.

When the primary excavation is completed, the work gantry 1 is constructed as shown in FIG. The construction procedure of this work gantry 1
First, the position where the work gantry 1 is to be constructed using the excavation recess 4 as a scaffold, that is, the wall portion of the retaining wall 3 facing the passage C side.
From the center of 3A, the wall 3B of the retaining wall 3 opposite the passage C
Then, the mold 8 is assembled at a portion reaching a position at a predetermined interval inward. At this time, at the upper end of the pile 2, a form 8 A for forming the beam 1 a of the work gantry 1 is assembled over the entire width of the form 8. The formwork 8 is supported by a large number of support jacks 9 erected on the bottom surface of the excavation recess 4. After assembling the formwork 8, concrete is poured into the formwork 8 so that the upper surface is located substantially on the same horizontal plane as the ground surface as shown in FIGS. And a part of the ground floor slab which has an opening 5 between the other three-side outer peripheral edge portion and the wall portion of the retaining wall 3 facing the three-side outer peripheral edge portion. The work gantry 1 is built.

After the work gantry 1 is built, the support jack 9 is removed, and the form 8 is dismantled and removed. On the other hand, as shown in FIGS. And the other end surface and both side end surfaces of the work gantry 1 facing the opening member 5 and the flared member 6 are formed as a plurality of piers. They are connected by a cutting beam member 7. When the ground B on which the retaining wall 3 is cast has a large supporting force, the bulging member 6 and the cutting beam member 7 do not always need to be provided.

Thereafter, as shown in FIG. 7, an excavating machine E such as a backhoe is put on the work gantry 1 to excavate the excavated recess 4 primarily excavated through the opening 5 further deeper. At this time, it is difficult to excavate the ground below the work gantry 1 with the excavating machine E on the work gantry 1. Excavation recess 4 is inserted into underground structure A
Secondary drilling to a depth that can be constructed.

After the secondary excavation, the foundation A1 of the underground structure A to be constructed is formed, and then the girder member 7 is removed. Until the foundation A1 is constructed, the plurality of piles 2 supporting the work gantry 1 may sink slightly, but after the foundation A1 is constructed, the piles 2 are fixed to and supported by the foundation A1. Since the sinking does not occur, the height of the work gantry 1 is checked in advance when the foundation A1 is cast, and if the sinking occurs, the height is corrected. After a while, the foundation surrounded by the retaining wall 3
An underground structure A is constructed on A1. The underground structure A to be constructed is indicated by a two-dot chain line in FIGS.

At the time of constructing the underground structure A, the pile body 2 supporting the work gantry 1 may be removed, but may be used as it is as a part of the column or wall of the underground structure A. . On the other hand, the work gantry 1 has the underground structure A as described above.
Ceiling slab, that is, a part of the floor slab of the first floor above the ground (ground floor slab), which is constructed prior to the construction of the entire slab. Therefore, the work gantry 1 is extended in the horizontal direction. A slab is formed in the ground floor slab.

The ground floor slab, which includes the work gantry 1 as a part, is formed by casting cast-in-place concrete as described above. However, a large number of precast concrete plates are laid together with the work gantry 1 and connected. If the ground floor slab is formed of a precast concrete plate in this way, the construction period can be shortened as compared with the case where cast-in-place concrete is cast. After the construction of the underground structure A, a high-rise building is constructed by constructing the ground floor.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal side view of a working gantry for underground structure construction,

FIG. 2 is a plan view thereof,

FIG. 3 is a simplified longitudinal side view of a state where primary excavation is being performed;

FIG. 4 is a plan view thereof,

FIG. 5 is a simplified longitudinal side view of a state where a work gantry is being created;

FIG. 6 is a plan view of the created work gantry,

FIG. 7 is a simplified longitudinal side view of a state where secondary excavation is being performed;

FIG. 8 is a construction flow diagram,

FIG. 9 is a longitudinal sectional side view for explaining a conventional example.

[Explanation of symbols]

 A Underground structure B Ground C Road 1 Work gantry 1a Beam 2 Pile 3 Mountain retaining wall 4 Excavation recess 5 Opening 7 Cut beam member

Claims (8)

[Claims] 1. A work gantry for constructing an underground structure in the ground surrounded by a retaining wall, wherein a plurality of piles are cast deeper than the bottom of the underground structure to be constructed. A part of the ground floor slab supported by these piles is constructed to form a work gantry with a part of the ground floor slab, and a part of the outer peripheral end of the work gantry is substantially flush with the ground surface. A working gantry for constructing an underground structure, wherein the working gantry is continuously flush with the above. 2. An end face of an outer peripheral end other than one end continuous with the ground surface of the work gantry on a substantially same horizontal plane and an upper end of the retaining wall are connected by a cutting beam member. The working gantry for constructing an underground structure according to claim 1, wherein: 3. The work gantry for constructing an underground structure according to claim 1, wherein a beam portion integrally provided on a lower surface of the work gantry is supported on an upper end of the pile body. 4. The work gantry according to claim 1, wherein the work gantry is formed by installing a plurality of precast concrete plates. 5. A step of constructing a mountain retaining wall around the underground structure to be constructed and driving a plurality of piles deeper than the bottom of the underground structure in the ground surrounded by the retaining wall. And a ground floor slab supported by the upper end of the pile body after primary excavation of the ground surrounded by the retaining wall, and such that a part of the outer peripheral end thereof is substantially flush with the ground surface and substantially flush with the ground surface. And constructing a work gantry with a part of the ground floor slab by constructing a part of the work gantry. 6. After forming the work gantry, an outer peripheral end surface of the work gantry other than a part of the outer peripheral end and an upper end of the retaining wall are connected by a cutting beam member. 6. The method for constructing a work gantry for constructing an underground structure according to 5. 7. After the work gantry is formed, secondary excavation is performed to a depth corresponding to the height of an underground structure to be constructed below and around the work gantry. The work gantry for underground structure construction according to claim 5 or 6, wherein a ground floor slab using at least a part of the work gantry and pillars and walls of the underground structure is constructed. How to build. 8. After the foundation of the underground structure is constructed,
6. When the height of the work gantry formed by a part of the ground floor slab is shifted from the height of the ground floor slab to be constructed, the shift is corrected.
A method for constructing a work gantry for constructing an underground structure according to claim 6 or 7.