JPH0219252B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention utilizes underground underground structures such as vertical piles, in particular, using the pile construction method and prefabricated products for underground structures that require subsequent on-site construction. Concerning construction methods and prefabricated underground structures used therein.

[Conventional technology]

Underground structures such as vertical piles and piers are often buried using the submerged box method.

Here, the submerged box construction method refers to a construction method in which the structure itself is built above ground, or prefabricated products are assembled into a predetermined structure and then buried underground.

[Problem to be solved by the invention]

By the way, depending on the soil quality of the excavated ground, it is necessary to protect the surrounding ground by using missing boards, corrugated walls, or continuous wall construction methods, etc., and to prevent loosening and water leakage around the board, due to safety concerns. Measures are required. These countermeasures require construction of ground improvement, drainage basins, well points, underpinning, etc. as the construction progresses, which creates problems in terms of economy, safety, speed, etc.

In addition, the foundation structure after the building frame is buried must be a reinforced concrete structure that is constructed on-site afterwards, and spring water treatment during the construction of the reinforced concrete bottom plate after burial is usually carried out inside the underground structure below the groundwater table. As a result, concrete cannot be poured under sufficient supervision, resulting in concrete that lacks watertightness, leaving the risk of defects such as water leakage. If this construction is used in conjunction with the sheet pile construction method, etc., a site area that includes the main frame and the required width of the sheet piles, center beams, etc. will be required, and in addition, when construction is carried out on the street, reconstruction boards will be temporarily placed for traffic reasons. It is necessary to proceed with the construction, and since using reconstruction boards on the road will hinder smooth traffic flow, it is requested that the construction be completed in a short time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for constructing an underground structure and a prefabricated underground structure that can compensate for the above-mentioned drawbacks and allow safe, economical, and quick work.

[Means to solve the problem]

The present invention aims to achieve the above-mentioned object, and the method is to suction and drain water using fixed steel pipes installed inside the stacked prefabricated blocks, or to carry out underground work and underground structures while draining water. build,
This is a construction method for underground structures in which grout is injected using the above-mentioned steel pipes during or after construction of the structure to create a solid ground around the underground structure, and it is also a prefabricated structure with communication holes formed in at least four corners. a lateral mass;
The lowermost block is inserted into the communication hole of the side blocks in the stacked state, and the lower end is screwed into the fixer, and the upper end The gist is a prefabricated underground structure consisting of steel pipes that protrude from the uppermost block and are used as drainage pipes and grout pipes.

[Embodiments of the invention]

Hereinafter, the first and second embodiments will be explained with reference to the drawings.
In the figure, 1 to 4 are side blocks made of prefabricated concrete having a rectangular or polygonal planar shape, and upper blocks 2, 3, and 4 are sequentially stacked on top of the lowest block 1.

A floor slab block 5 having a manhole entrance/exit hole 5a is mounted on the uppermost block 4.

6 will be made of concrete bottom slab and will be constructed on site after the lowest block 1 has settled using the submerged box construction method.

In addition, the lowest side block 1 has a step on the outer wall surface compared to the other side blocks 2 to 4 in order to ease the frictional resistance caused by the soil around the side block and facilitate settlement during subsidence by the submerged box construction method. This aims to reduce the frictional force between the front and side blocks.

In addition, step portions 1a, 2a, 3a are formed around the entire circumference on each horizontal joint surface of each of the side blocks 1 to 4, and a sponge 8 impregnated with plastic rubber 7 or epoxy resin is placed on these steps. The aim is to create an adhesive effect between the blocks and prevent water leakage.

Further, vertical communication holes 1b, 2b, 3b, 4 are provided in at least four corners of each side block 2 to 4 and the floor slab block 5.
b, 5b are formed, and an external through hole 1c having an opening on the outside at a point near the lowest part is formed in the lowest side block 1, and a T-shaped fixing fitting 9 is embedded in this external through hole 1c. has been done.

Next, the construction method (in the case of an underground manhole in this example) will be explained.

First, on the ground, the side blocks 1 to 4 are sequentially stacked with the plastic rubber 7 or sponge 8 interposed therebetween as described above. At this time, each communication hole 1 of each side mass 1 to 4
b to 4b are each communicated as one hole.

Next, the steel pipe 1 is inserted from each communication hole 4b of the lowermost block 4.
0 to the fixing metal fitting 9, and screwing the lower end screw part of the steel pipe 10 into the female threaded part of the fixing metal fitting 9, and plug 20 into the internal female threaded part of the fixing metal fitting 9.
Screw them together.

Further, a filter 13 is attached from the outside to a portion opened to the outside of the external passage hole 1c of the lowermost block 1 in which the fixing metal fitting 9 is embedded. After all of the side blocks are stacked, a fixing plate 19 and a nut 14 are attached to the steel pipe 10 protruding from the communication hole 4b of the uppermost side block 4.
The side blocks 1 to 4 are thereby integrated with each other by temporary tightening.

Next, a center hole hydraulic jack is inserted into the upper part of the steel pipe 10, the steel pipe 10 is tensioned within the allowable stress range of the steel pipe tensile strength, and the nut 14 is finally tightened.

The fixing plate 19 has a grout hole 21 and serves both of filling the surrounding area of the steel pipe 10 and fixing the steel pipe 10. In addition, Nut 2 is installed in the grout hole.
It is also possible to tighten by 1' (Figure 4).

Next, shear reinforcing bars are placed on the lowermost block 1 and concreting work is carried out, but if loosening or spring water occurs around the ground, sufficient watertight concrete casting cannot be performed.

Therefore, in the present invention, a method is adopted in which a vacuum pump is connected to the protruding end of the above-described steel pipe 10 to suck spring water. There is no possibility that the inside of the steel pipe 10 will be clogged by the filter 13 during this suction and drainage. This allows reinforcing and concreting to be carried out under conditions similar to normal surface work, even below the groundwater level, thereby improving the accuracy, quality, efficiency and safety of a given structure. can be increased.

After the concrete pouring of the bottom slab is completed and the specified strength is obtained by the above-mentioned means, the protruding tip of the steel pipe 10 used as the suction and drainage pipe is removed from the vacuum pump, and this time it is connected to the grout pump. Then, inject grout using mortar milk, etc. At this time, the filter 13 is discharged from the external hole 1c by the pressure of the grout, and the grout flows out around the opening of the external hole 1c.

Therefore, the loosening of the ground around the lowermost side block 1 and the bottom surface of the bottom slab can be prepaced by grouting, and the surroundings of the ground can be improved and ground subsidence can be sufficiently prevented.

Next, the slab block 5 is placed on top of the uppermost block 4, and screwed and fixed with nuts using the steel pipe 10. The floor slab mass 5 is provided with a communication hole corresponding to the lower side mass, and after the above-mentioned fixation, an end treatment is performed using a corrosion-resistant cap.

The top of the slab usually contacts the ground with a manhole ring. If the underground structure is a shaft or the like, it is possible to start work on the side hole or propulsion pipe as is, without requiring horizontal members such as center beams or uprights. After the work is completed, the structure itself can be used as a manhole frame, so the work can be completed with the installation of the slab mass and manhole ring.

In addition, if the purpose of construction of the side block is a propulsion shaft, suction and drainage can be continued even during the construction of the propulsion pipe. The grouting performed later contributes to preventing ground subsidence or immobility settlement around the propulsion pipe.

〔Effect of the invention〕

As described above, the present invention allows steel pipes to be inserted and fixed into the communication holes of the stacked side blocks, and underground spring water can be drained using the steel pipes, so that concrete construction of the bottom plate as a pressure plate can be performed reliably. and,
It can be carried out quickly, and after the drainage work is completed, grout can be injected through the steel pipes mentioned above to improve the ground, so the work time can be shortened and the work site area can be minimized compared to performing drainage and grouting as separate works. This makes construction easier and can greatly reduce traffic confusion on the road.

In this example, for a 40 cubic meter underground manhole, the slab was completed within 48 hours from the start of the frame installation, which is an extremely rapid effect compared to open excavation work, which normally takes one to two months. has.

[Brief explanation of drawings]

The figures show an embodiment according to the present invention, and FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line ``-'', FIG. 3 is a sectional view taken along the ``-'' line in FIG. This is an enlarged view. 1 to 4... Side mass, 1b, 2b, 3b, 4b, 5
b...Communication hole, 9...Fixing metal fitting, 10...Steel pipe.

Claims (1)

[Scope of Claims] 1. Suction and drainage using fixed steel pipes provided inside the stacked prefabricated side blocks, or construction of underground structures and underground structures while draining water, during or after the construction of the structures. A construction method for underground structures in which grout is injected using the above-mentioned steel pipes to create a solid foundation around the underground structure. 2. A prefab side block having communication holes formed in at least four corners, and a lowermost side block in which a fixing metal fitting is embedded in a communication hole that communicates with the communication hole of the prefab side block;
inserted into the communication hole of the side block in a stacked state,
A prefabricated underground structure comprising a steel pipe whose lower end is screwed into the fixing fitting and whose upper end protrudes from the uppermost block and is used as a drainage pipe and a grout pipe.