JPH02140329A - Prefabricated underground structure - Google Patents

Abstract

PURPOSE:To safely and economically construct an underground structure by inserting and fixing a steel pipe and a PC steel bar respectively to communicating holes of stacked side lumps and utilizing the steel pipe to discharge the underground spring water. CONSTITUTION:After multiple side lumps 1-4 are stacked and communicating holes 1b-4b are bored, a steel pipe 10 is inserted into the communicating holes 1b-4b on one side to a fixing metal 9, the lower end of the steel pipe 10 is screwed, and a plug 20 is screwed on the inner side of the metal 9. A PC steel bar is inserted into the communicating holes 1b-4b on the other side to a fixing metal, and its lower end is screwed. The steel pipe 10 and the steel bar protruded from the communicating hole 4b of the uppermost side lump 4 are temporarily fastened and fixed with a nut 14 to integrate the side lumps 1-4, then the steel bar is stretched by a hydraulic jack and formally fastened and fixed with the nut 14. A vacuum pump is connected to the protruded tip of the steel pipe 10, and spring water is sucked via a filter 13. After concrete is placed on the lowermost side lump 1, grout is filled via the steel pipe 10.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to the use of prefabricated products for underground underground structures such as vertical shafts, especially underground structures that require the pile construction method and subsequent on-site construction. Concerning construction methods and prefabricated underground structures used therein.

[Prior Art] Underground structures such as shafts and piers are often buried using the underground box construction 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 ground where the submersible is excavated, it is necessary to protect the surrounding ground by using board loss, corrugated or continuous wall construction methods, etc., and also to take preventive measures such as loosening around the board and water removal. . These countermeasures require construction such as ground improvement, drainage strain field, well points, and underpinning 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 It is an object of the present invention to provide a prefabricated underground structure that overcomes the above-mentioned drawbacks and allows for safe, economical, and quick work.

[Means to solve the problem]

The present invention aims to achieve the above-mentioned object, and its means include a prefabricated block having communicating holes formed in at least four corners, and a fixing fitting embedded in the communicating hole communicating with the communicating hole of the prefabricated block. inserted into at least two or more of the communication holes of the side blocks in the stacked state, the lower end is screwed to the fixing metal fitting, and the upper end protrudes from the uppermost side block. A PC steel rod with a nut screwed together to integrate the side blocks, and a PC copper rod in the communication hole of the side block in the stacked state are inserted into the communication hole in which the PC copper rod is not inserted, and the lower end is connected to the fixing metal fitting. The gist of this is a prefabricated underground structure comprising a steel pipe which is screwed together with a steel pipe whose upper end protrudes from the uppermost block and is used as a drainage pipe and a grout pipe.

[Embodiments of the invention]

Hereinafter, the embodiment will be explained with reference to the drawings. In Fig. 1.2, 1 to 4 are side blocks made of prefabricated concrete having a rectangular or polygonal planar shape.
The upper side blocks 2.3.4 are stacked one after another on top.

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 lowermost side block 1 is provided with a step on the outer wall surface compared to the other side blocks 2 to 4 in order to reduce IY friction resistance due to the soil around the side block and to facilitate settlement during subsidence by the submerged box construction method. Efforts are being made to reduce the frictional force between the earth and sand and the side blocks.

In addition, stepped portions 1a, 2a, and 3a are formed around the entire circumference on each horizontal joint surface of each of the side blocks 1 to 4, and a W flexible rubber 7 is formed on the stepped portions 1a, 2a, and 3a.
A sponge 8 impregnated with epoxy resin is placed to provide adhesion between the side blocks and prevent water leakage.

Furthermore, vertical communication holes 1b, 2b, 3b, 4b5b are formed in at least the four corners of each of the side blocks 2 to 4 and the slab block 5, and the lowest side block 1 has an opening outward at a point near the bottom. An external through hole 1c is formed, and a fixing fitting 9.9' is formed in this external through hole 1c.

Examples of the fixing metal fittings 9 and 9' are shown in Fig. 45; in the fourth article, a pear-shaped one was used, and in Fig. 5, a box-shaped one was installed in the concrete. It is buried.

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 of the communication holes 1b to 4b of each of the side blocks 1 to 4 is communicated as one hole.

Next, the steel pipe 10 is passed through each communication hole 4b of the lowermost block 4 to the fixing fitting 9, and the lower end threaded portion of the steel pipe 10 is screwed together, and the plug 20 is screwed into the inside of the fixing fitting 9.

In addition, the PC steel rod 10' is attached to the fixing metal fitting 9' in the remaining communication hole.
The NAND 1 is inserted into the threaded portion of the lower end of the PC steel bar
1 are screwed together, and then sealed with a fixing agent 12 such as mortar to maintain sufficient watertightness.

A filter 13 is attached from the outside to the external through hole 1c that communicates with the fixing metal fitting 9 or the external through hole 1 that communicates with the fixing metal fitting 9' via the socket 71□22. After all of the side blocks are stacked, the steel pipe 10 and PC steel bar 10' protruding from the communication hole 4b of the uppermost side block 4 are temporarily tightened with nuts 14, thereby integrating the side blocks 1 to 4. do. Note that when screwing the nut 14 onto the steel pipe 1o, the fixing plate 19 is also fixed integrally.

Next, insert a center hole hydraulic jack into the upper part of the PC steel bar 10', and set the PC in the allowable stress range of the steel pipe tensile strength.
The steel rod 10' is tensioned and finally tightened using the Nand 14.

The fixing plate 19, which is fastened to the steel pipe 10 with a nut 14, has a grout hole 21 and serves both of the effect of filling the surrounding area of the steel pipe 1o and the role of fixing the copper pipe 10. Note that it is also possible to tighten the grout/hole with two nuts (Figure 4). Further, 12' shown in Fig. 5 is also a grout hole, but this plow 1 hole 12' is filled with -F-rutar and mortar is injected through a thin flexible vinyl or rubber pipe. , Concreting work is performed by placing shear reinforcing bars on the lowermost block 1, but if loosening or spring water occurs around the ground, sufficient water-tight concrete casting cannot be performed.

Therefore, in the present invention, a method is adopted in which a vacuum pump is connected to the protruding tip of the above-mentioned steel pipe 1o to suck spring water. A filter 13 acts on this suction waste water so that the inside of the steel pipe 10 is not clogged. This allows reinforcing and concreting to be carried out under conditions similar to normal surface work, even below the groundwater table, thus increasing the accuracy, quality, efficiency and safety of a given structure. be able to.

Then, after completing the concreting of the bottom slab and obtaining the desired strength by the above-mentioned means, the protruding tip of the steel pipe 1o used as the suction and drainage pipe was removed from the vacuum pump, and this time it was connected to the grout pump. 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 IC.

Therefore, the loosening of the ground around the lowermost mass I and the bottom of the bottom slab can be affected by grouting, improving the surroundings of the ground and sufficiently preventing ground subsidence.

Next, the floor slab block 5 is placed on top of the uppermost side block 4, and the steel pipe 10
Use a screwdriver to secure it by screwing it together. The floor slab mass 5 is provided with a communication hole corresponding to the lower side mass, and after the above-mentioned fixation,
Perform terminal treatment using corrosion-resistant camp.

Filled slabs usually come into contact with the ground through a manhole concave ring. If the underground structure is a vertical shaft, etc., there is no need for horizontal members such as center beams or uprights (it is possible to start horizontal tunnel work or propulsion pipe work as is. After the work is completed, the structure itself Since it can be used as a manhole frame, the construction work can be completed with the installation of the floor slab mass and manhole concave 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.

[Effects of the Invention] As described above, the present invention inserts and fixes the steel pipe and P (Jl bar) into the communication holes of the stacked side blocks, so that in particular, each side block can be integrated with the PC steel rod, and Since underground spring water can be drained using steel pipes, construction of the bottom slab concrete as a pressure plate can be done reliably and quickly.
After the drainage work is completed, grout can be injected through the steel pipes mentioned above to improve the ground, so it is easier to do the work by shortening the work time and minimizing the work site area, compared to doing drainage and grouting as separate works. This can greatly reduce traffic confusion on the roads.

In this example, in a 40 cubic meter underground man-hole, construction was completed from the start of the frame installation to the slab block within 48 hours, which is extremely fast compared to excavation work which normally takes 1 to 2 months. It has a sexual effect.

[Brief explanation of the drawing]

The figures show an embodiment according to the present invention, with the first figure being a plan view and the second figure being a plan view.
The figure is a sectional view taken along the line nn of the same as above, and Figure 3 is the I-II line in Figure 1.
I-line sectional view, Figure 4.5 is an enlarged view of the fixing metal part, Figure 6
The figure is a half-sectional view showing the construction state. 1 to 4-side mass, lb, 2b, 3b, 4b, 5b communicating hole,
9. 9′ fixed fitting, 10-steel pipe, ■OPC steel bar.

Claims (1)

[Scope of Claims] A prefabricated block having communicating holes formed in at least four corners; a lowermost block having a fixing fitting embedded in a communicating hole that communicates with the communicating hole of the prefabricated block; and a side in a stacked state. It is inserted into at least two or more of the communicating holes of the block, the lower end is screwed to the fixing metal fitting, the upper end is protruded from the uppermost side block, and a nut is screwed together to integrate the side blocks. The PC steel rods are inserted into the communication holes of the side blocks in the stacked state where the PC steel rods are not inserted, the lower ends are screwed into the fixing fittings, and the upper ends are connected to the uppermost side blocks. A prefabricated underground structure characterized by comprising: a protruding steel pipe used as a drainage pipe and a grout pipe;