JP2001207457A - Drain box for shallow sump, and work method for underground structure using the drain box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform definite drainage on the job site for an underground structure and also to reduce construction cost. SOLUTION: A drain box 1 capable of definitely carry out drainage of underground water to a shallow swamp 15 and preventing water leakage is embedded in a drain box 1 in constructing the underground structure. At the water- conveyance holes 6 for ground water provided in the surroundings of a drum portion 2 of the drain box 1, stopcocks 8, capable of opening/closing the holes, are installed in the inside. Ground water is able to ingress in a state where the water-conveyance hole is open during the work, and upon the completion of the work, the cock is closed and the underwater pump 5 is made recoverable under the dry state in the drain box 1. After the form 18 is installed and an underground slab is installed, the inside of the box is backfilled, the vicinity of the upper end portion of the box at the trace of removing the from is coated with a water sealing material, and a water leakage from the shallow sump 15 to the top of the underground slab can be prevented surely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage box for a kamaba at a construction site of an underground structure and a method of constructing an underground structure using the same.

[0002]

2. Description of the Related Art As is well known, drainage measures for groundwater are indispensable for construction of underground structures such as basements. In a construction site of a normal underground building, for example, a construction site of a basement building, an underground slab serving as a base is first constructed. In this case, drainage is performed during the excavation work of the ground,
After excavation of the inside surrounded by steel sheet piles is completed,
As shown in (a), a drain groove 62 is provided along a steel sheet pile 61 on the bottom surface of the ground, and the collected groundwater is drained to the ground surface by a drain pump 63.

The groundwater flowing into the drain 62 from underground is collected at a pot 65 provided at a key point through a guide channel 64, and is drained by the drain pump 63 installed here. .

As shown in FIG. 5 (b), the underground slab 60 is constructed on the drainage channel 62 and the guide channel 64, so that the drainage pipe or the side channel is covered with a lid. I have. The drainage grooves 62 and the guiding water passages 64 are provided with through holes through which the groundwater flows, so that the groundwater can flow into the bottom ground or be collected.

[0005] Also, inside the steel sheet pile 61, the groundwater flowing from the gap of the steel sheet pile is collected in the drainage groove 62 without flowing into the underground slab or the underground wall.
6 are provided.

[0006] The rough construction procedure of the underground slab 60 serving as the base of the underground structure is as follows. A kama place 65 and a guide channel 64 connecting the kama place and the drainage groove 62 are provided everywhere on the bottom ground 67.
A mold 68 for providing a passage for a drain hose is provided above the kneading place. A waterproof sheet (not shown) is laid on the bottom ground 67, a split stone layer 69 is laid thereon, and a discarded concrete layer 70 is formed thereon, and furthermore, it has excellent strength and waterproofness. A pressure-resistant concrete layer 71 having properties is formed.

When the underground slab 60 is completed, the underground wall 72 is provided next, and the formwork 68 is finally removed.
Then, the cavity formed thereon is filled, and the pressure-resistant concrete layer 71 is replenished with fresh concrete and closed, and finally, a mortar layer 73 is formed on the surface.

In addition, during the above construction, since the groundwater constantly flows into the kiln yard 65, the drainage work must be continued until the filling of the mortar or other waterproof material into the cavity formed on the kiln yard. No. Therefore, the drainage pump 63 must be operated even during the filling of the waterproof material, and the submersible pump cannot be removed.

[0009]

Since the kamaba 65 in the above conventional example is always in communication with the guide water channel 64, the groundwater is still discharged from the kamaba 65 even after the formation of the pressure-resistant concrete layer 71 of the underground slab. Backflow slab 60
There is a risk of overflowing to the upper surface of the device. Therefore, the form 6
The drain pump 63 must be operated even after removing 8.

For this reason, the pump cannot be stopped until the cavity after the removal of the mold is filled with a water-stopping material such as mortar. As a result, as described above, the expensive pump is eventually buried and killed. If an inexpensive pump with low performance is adopted to reduce the economic loss due to burial of the pump, drainage during construction will be insufficient and the quality of concrete will deteriorate, so install an inexpensive pump. Also has limitations.

If the formwork 68 provided above the kiln yard 65 is not sufficiently waterproof at the boundary with the underground slab 60, the groundwater flowing backward from the kiln yard may cause the dumping concrete layer 70 and the pressure resistant There is a possibility that the concrete enters into the concrete layer 71 and becomes inflated concrete having low strength.

Furthermore, in the prior art, if the waterproofness of the waterproof material to be filled in the cavity after removing the cavity of the kiln yard 65 and the formwork 68 is not perfect, the underground slab is required. There is also a problem that groundwater rises to the upper surface.

Accordingly, an object of the present invention is to firstly prevent deterioration of concrete quality by preventing groundwater from entering into concrete being poured during construction of an underground slab. Second, to enable the recovery of expensive drainage pumps. Thirdly, it is to completely prevent the flow of groundwater from the kamaba to the upper surface of the underground slab after the completion of the construction of the underground structure.

[0014]

In order to achieve the above object, the present invention employs the following means. First, it is possible to construct an underground building under complete drainage using a drain box provided with the following elements at a kneading place at the construction site of the underground building. Here, the drainage box is a box that promotes drainage of groundwater by burying in the stove instead of the drainage basin provided in the stove in the prior art, and has the following elements. .

The above-mentioned drain box has a body in which a submersible pump can be installed, an upper opening in which a submersible pump for drainage can be taken in and out of a cylinder formed in the upper end of the body, and a base for catching groundwater. A plurality of water inlets provided around the trunk so as to be connectable to the guide water channel provided at the construction site of the underground building to guide the site, and a water stopcock that can open and close these water inlets from the inside It is provided. In addition, this drain box is manufactured in advance in a factory, and is carried into a construction site to be installed.

By employing the above drain box, it is possible to easily set up a stove installed at the construction site of the underground building, and to completely prevent leakage of groundwater after the backfill of the stove. Further, the construction cost can be reduced by making the submersible pump recoverable.

Secondly, the method of constructing an underground structure using the above-described drainage box employs the following steps so that drainage during construction is completely performed. A first step of burying a drain box manufactured in a factory in a stove provided at various places in the construction site of the underground construction and providing a formwork for passing a drain hose above the opening; The second step of connecting the diversion channel provided to guide the groundwater at the site to the kiln site, and installing a submersible pump in the body of the drain box, and draining the groundwater introduced into the drain box with the submersible pump The third step of constructing the underground slab while constructing the underground slab, closing the water intake and stopping the inflow of groundwater into the drain box, collecting the submersible pump stored in the drain box, A fourth step of removing the formwork, a fifth step of removing the formwork, filling the inside of the drain box with a backfill material, and surrounding the periphery of the upper end of the cylindrical portion with the first water-stopping material. Including There as.

Third, in the above-mentioned construction method, the third step includes a step of surrounding the periphery of the upper opening surrounded by the mold with a second waterproof material. It is possible to completely prevent the leakage of groundwater.

Fourthly, in the above construction method, swelling bentonite is used as the first water-stopping material in the fifth step, so that leakage of groundwater from the kiln can be completely prevented. .

[0020]

Embodiments of the present invention will be described below with reference to the drawings. First, the drain box will be described with reference to FIGS.

The drainage box 1 has a rectangular parallelepiped container-shaped body 2 and a rectangular parallelepiped tube 3 provided on the upper part of the body. Each of the body 2 and the tube 3 is made of a so-called sheet metal product assembled by joining steel plates by welding, and the upper part of the body inside the tube is cut out to form an upper opening 4. The inside of the body 2 is sized to accommodate the submersible pump 5, and the above-described upper opening 4 is sized to allow the pump to be taken in and out.

Further, a circular water inlet 6 is provided at each upper part of each side of the body 2 (only two water inlets are shown). The water inlet 6 is an inlet hole for guiding groundwater from the later-described guide water channel into the drain box 1, and is surrounded by the base of the cylindrical sleeve 7 in the body. The sleeve 7 has a base portion of a steel pipe fixed to the inside of the body portion 2 by welding, and a male thread portion 7a is cut at a tip end portion.

A stopcock 8 is placed on the tip of the sleeve 7 so that the inflow of groundwater from the water inlet 6 can be stopped. The water stopcock 8 is made of a steel cap nut, and the female thread 8a cut on the opening side is a male thread 7 of the sleeve.
a can be screwed. The number of the water introduction ports 6 is determined according to the actual condition of the construction site. Unnecessary installation of water inlets will increase costs and cause water leakage, so the number of water inlets should be determined according to the actual situation.

Next, a method of constructing an underground building employing the above drain box will be described with reference to FIGS.

FIG. 3 shows a process state of construction of a basement using the drain box 1 described above. In this figure, the construction of the underground slab 11 located on the lowest floor of the basement has been completed. However, in the following description, drainage of groundwater will be described for the processes from the digging of the ground to the completion of the underground slab and the underground wall. Will be sequentially described.

First, a steel sheet pile 12 is driven around a construction site of an underground structure, as in the prior art, and the inside thereof is excavated. Next, a drainage groove 13 for groundwater is provided along the inside of the steel sheet pile on the bottom ground, and a guide channel 14 and a kamajo 15 are provided everywhere.
Is provided.

Further, inside the steel sheet pile 12, there is provided a stitch plate 16 for collecting water leaking from an underground excavation surface downward along the steel sheet pile surface. The stitch plate 16 is provided so that the lower part is located between the steel sheet pile 12 and the drain groove 13 and the upper part has a height substantially coincident with the upper surface of a pressure-resistant concrete layer described later.

The above-mentioned drain box 1 is buried in the concave part serving as the pot place 15 so that the water inlet 6 can be connected to the guide channel 14. The drainage channel 13 and the guide channel 14 are provided with groundwater inlets everywhere, so that groundwater underground can be collected and introduced into the drainage box 1.

Next, a water stop member 17 made of a bentonite sheet is attached to the periphery of the cylindrical portion 3 of the drain box 1, and a mold 18 is provided so as to surround the periphery (first step). The presence of the water blocking member serves to prevent water leakage from between the outer peripheral portion of the cylindrical portion 3 and the mold 18. The formwork 18 allows the drainage pump 5 to be taken in and out, and plays a role in passing the drainage hose 9. The installation of the formwork 18 may be performed after the laying of the split stone layer 19 described later. The water blocking member 17 functions to prevent water leakage from between the drain box 1 and the mold 18. The upper end of the formwork 18 is installed at a height higher than the upper surface of a pressure-resistant concrete layer described later.

Next, the submersible pump 5 is installed in the drain box 1, the water stopcock 8 is removed, the water inlet 6 is opened, and groundwater is collected in the drain box. The collected groundwater is drained to the ground via the hose 9 (second step).
The submersible pump 5 is provided so that groundwater can be sucked through a strainer 5b mounted on a base 5a.

Next, a waterproof sheet (not shown) is laid on the bottom ground including the guide channel 14, and a split stone layer 19 is formed by laying medium-sized cobble stones thereon. The upper surface of the split chestnut stone layer 19 has a height substantially coincident with the upper end of the body 2 of the drain box 1.

Next, bentonite powder is applied in a substantially triangular cross section around the formwork 18 connecting the upper surface of the body portion 2 of the drain box 1 and the intermediate position of the cylindrical portion 3 to form the water stopping portion 20. The water stopping portion 20 may be formed of mortar or the like.

Next, a waterproof sheet is laid on the upper surface of the split-stone layer 19, and a concrete layer 21 is formed on the waterproof sheet to a height (about 160 mm) substantially coincident with the upper end of the drain box 1. When the discarded concrete layer 21 has hardened, a waterproof plate 22 having an L-shaped cross section is arranged along the inside of the cling plate 16 and a waterproof sheet 23 is further arranged inside the waterproof plate 22. The waterproof sheet 23 is provided so as to double overlap with the water stop plate 22 in a range where the water stop plate 22 is provided, and to be parallel to the steel sheet pile 12 in a range above the clog plate 16.

When the upper part of the discarded concrete layer 21 is covered with the waterproof sheet 23 in this way, a pressure-resistant concrete layer 24 is then cast thereon. The pressure-resistant concrete layer 24 has a thickness of approximately 300 mm,
Except for the portion 8, it is cast on the entire underground floor (third step).

The underground slab 11 along the steel sheet pile 12
An underground wall 25 is built on top. The underground wall 25 is formed by interposing the waterproof sheet 23 inside the steel sheet pile 12 so that groundwater does not flow into the concrete being poured.

Next, while draining by the submersible pump 5, a hand is put into the drain box 1 from the upper surface side of the underground slab 11, and caps (water stopcocks) are put on all the sleeves 7.
8, the water inlet 6 is closed, and the inflow of groundwater from the guide channel 14 is stopped. Shortly thereafter, all the groundwater remaining in the drain box 1 is drained by the submersible pump. Next, the submersible pump 5, the strainer 5b and the hose 9 are pulled up and collected, and the formwork 18 is removed (fourth embodiment).
Process).

Next, as shown in FIG. 4, the emptied drain box 1 is filled with a backfill material 26 such as earth and sand or debris and squeezed. The filling amount of the backfill material 26 is set up to the vicinity of the upper end of the tubular portion 2. Next, a water-blocking material 27 made of bentonite powder is put into a cavity formed inside the cylindrical portion 3 to surround the periphery and the upper portion of the cylindrical portion 3 and to perform a process for preventing groundwater from leaking from the drain box 1 ( Fifth step).

Next, a filled concrete portion 28 is provided by filling and solidifying ready-mixed concrete in the cavity left above the submersible pump. In order to form a surface mortar layer 29 on each of the upper surfaces of the pressure-resistant concrete layer 24 and the filled concrete portion 28, the filled concrete portion 28 filled in the cavity left over the drain box 1 is formed.
Does not appear on the surface of the underground slab 11.

Although the construction method described above is merely an example, and there are many actual construction examples, the present invention facilitates the installation of the drainage structure by first installing the drainage box 1 on the stove 15. thing. Second, the inflow of groundwater into the drain box can be stopped by closing the stop cock 8 after removing the mold. Third, the submersible pump can be recovered after removing the mold. Fourth, after filling the backfill material in the kamaba box 1 after the submersible pump is recovered, the opening 4
Is characterized in that groundwater can be prevented from leaking from the gap of the pressure-resistant concrete layer by arranging bentonite around the periphery.

In this example, the shape of the drain box is a rectangular parallelepiped. However, the shape is not limited to this, and the material can be made of a synthetic resin or other material in addition to a steel plate. Although the stopcock is described as a cap-shaped stopper, the stopper may be formed in a rod shape, a screw may be cut in the stopcock, and a female screw may be cut in the opening side of the sleeve.

The effect of the present invention is not affected even if the order of the steps of the installation of the formwork and the formation of the split stone layer and the discarded concrete layer is reversed from the above description.

[0042]

The use of the drainage box according to the present invention facilitates installation of a kiln at a construction site of an underground structure, and also enables construction without leakage of groundwater.
Further, since the water inlet of the drain box is openable and closable, the water in the drain box can be removed by closing it at a predetermined construction time. Therefore, it is possible to recover the submersible pump after closing the water inlet. Along with this, even if backfill material is filled after pump recovery,
Since the water level does not rise from below, it is possible to backfill the kamaba with plenty of time.

Further, by forming a water stop portion around the cylindrical portion of the drain box at the time of construction, it is possible to prevent groundwater from leaking from around the formwork.

Furthermore, if a water-blocking material such as bentonite is arranged around the opening after removing the formwork, it is possible to completely prevent the rise of groundwater from inside and outside of the kamaba box.

If the present invention is applied to the construction of an underground building, since the waterproofing measures are complete, the phenomenon of water inflation in the concrete at the time of concrete casting is eliminated, so that an underground building made of high-quality concrete can be obtained. can get.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a drain box.

FIG. 2 is a perspective view showing an example of the appearance of a drain box.

FIG. 3 is a cross-sectional view showing a construction example of an underground building employing a drain box.

FIG. 4 is a cross-sectional view showing a state after the completion of construction.

5A and 5B show a conventional example, in which FIG. 5A is a plan view and FIG.
FIG. 3 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drainage box 2 Body part 3 Tube part 4 Upper opening 5 Submersible pump 6 Water inlet 8 Water stopcock 11 Underground slab 12 Steel sheet pile 13 Drainage groove 14 Guide channel 15 Kamajo 18 Formwork 20 Water stop part 26 Backfill material 27 Stop Water material (bentonite)

Claims (4)

[Claims] 1. A torso capable of accommodating a submersible pump, a tubular portion formed at an upper end of the torso, an upper opening through which the submersible pump can be inserted and removed, and a periphery of the torso. Characterized by a plurality of water inlets provided in the car, and a water stopcock for opening and closing these water inlets from the inside. 2. A first step of burying the drainage box according to claim 1 in a stove provided at a key point of a construction site of an underground building, and providing a formwork around the cylindrical portion; A second step of installing the submersible pump in the water tank and opening the water inlet; a third step of constructing an underground slab while draining the underground water introduced into the drain box with the submersible pump; After the construction, close the water inlet,
A fourth step of recovering the submersible pump from the drain box and removing the formwork, filling the drain box with a backfill material, and surrounding an upper surface of the backfill material and an upper end of the cylindrical portion. And a fifth step of forming a water-stopping section surrounding the water-blocking material with a water-stopping material. 3. The method according to claim 2, wherein the third step includes a step of surrounding the upper end of the trunk and the periphery of the form with a waterproof material. 4. The method according to claim 2, wherein the water-blocking material used in the fifth step is bentonite.