JP3451050B2 - Construction method for underground structures - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground structure, which is carried out by using a drainage box for a kamaba at a construction site for the underground structure.

[0002]

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

Groundwater flowing into the drainage ditch 62 from the ground is collected through a guide water channel 64 to a kamaba 65 provided at a key point, and is drained by the drainage pump 63 installed here. .

As shown in FIG. 5 (b), since the underground slab 60 is constructed on the drainage channel 62 and the guiding channel 64, the drainage channel or the gutter with the lid is continuously buried. There is. The drainage groove 62 and the guiding water channel 64 are provided with through holes through which groundwater flows in, so that the groundwater that flows into the bottom ground or springs out can be collected.

Further, inside the steel sheet pile 61, the ground plate 6 is arranged so that the groundwater flowing into the gap of the steel sheet pile can be collected in the drainage ditch 62 without flowing into the underground slab or the underground wall.
6 is provided.

The rough construction procedure of the underground slab 60, which is the base of the underground structure, is to install a kamaba 65 everywhere on the bottom ground 67 and a guiding water channel 64 connecting the kamaba and the drainage groove 62.
A mold 68 for providing a passage for the drain hose is provided above the kamaba. Although not shown in the drawing, a waterproof sheet is laid on the bottom ground 67, and a split stone layer 69 is laid on it, and a discarded concrete layer 70 is formed on it, which is excellent in strength and waterproofness. A pressure resistant concrete layer 71 having properties is formed.

When the underground slab 60 is completed, an underground wall 72 is provided next, and finally the form 68 is removed, and the kamaba 65
Further, the cavities formed above are filled up, and the pressure-resistant concrete layer 71 is supplemented with fresh concrete to close it, and finally the mortar layer 73 is formed on the surface thereof.

Since groundwater constantly flows into the sickle 65 during the above construction, the drainage work must be continued until the filling of the water blocking material such as mortar into the cavity formed above the sickle. I won't. Therefore, the drainage pump 63 must be operated even during the filling of the water blocking material, and therefore the drainage pump cannot be removed, so that this pump is eventually buried.

[0009]

Since the kamaba 65 in the above-mentioned conventional example is always in communication with the guiding water channel 64, groundwater is still discharged from the kamaba 65 even after the pressure resistant concrete layer 71 of the underground slab is formed. Backflow and underground slab 60
May overflow to the upper surface of the. Therefore, the formwork 6
The drainage pump 63 must be operating even after removing 8.

For this reason, the pump cannot be stopped until the cavities after the mold is removed are filled with a water blocking material such as mortar, so that the expensive pump is eventually buried as described above. If an inexpensive pump with low performance is adopted in order to reduce the economic loss due to the burying of the pump, the drainage during construction will be insufficient and the quality of the concrete will deteriorate, so an inexpensive pump should be installed. There is also a limit.

Further, if the formwork 68 provided above the kamaba 65 is insufficiently waterproof at the boundary with the underground slab 60, the groundwater that has flowed back from the kamaba will be discarded and the pressure-resistant concrete layer 70 will be used during pouring. There is a risk that it may enter the concrete layer 71 and become inflated concrete having poor strength.

Furthermore, in the prior art, when the waterproofing material for filling the cavity portion of the rotary hook 65 and the cavity after removing the form 68 is not completely waterproof, the underground slab is used. There is also a problem that groundwater rises to the upper surface.

Therefore, firstly, the purpose of the present invention is to prevent the deterioration of the quality of concrete by preventing the ingress of groundwater into the concrete being poured during the construction of the underground slab. Second, to enable the recovery of expensive submersible pumps for drainage. Thirdly, it is to completely prevent the groundwater from spilling from the stove to the upper surface of the underground slab after the construction of the underground structure is completed.

[0014]

In order to achieve the above object, the present invention adopts the following means. It is possible to construct an underground structure under a complete drainage condition by using a drainage box equipped with the following elements in the construction site of the underground structure. Here, the drainage box is a box body that promotes the drainage of groundwater by burying it in the sickle, instead of the drainage basin provided in the sickle in the prior art,
It has the following elements.

The drain box described above is provided with a body portion on which a submersible pump can be installed, an upper opening provided for allowing a submersible pump for drainage to be taken in and out of a tubular portion formed at an upper end portion of the body portion, and ground water. In order to guide to the site, a plurality of water inlets provided around the above-mentioned trunk so that it can be connected to the water canal provided in the construction site of the underground structure, and a water stopper that can open and close these water inlets from the inside Be prepared. In addition, this drainage box is manufactured in advance in a factory, and is carried into a construction site for installation.

By adopting the above drainage box, it is possible to easily install the kettle provided at the construction site of the underground construction and to completely prevent leakage of ground water after backfilling the kettle. Further, by making the submersible pump recoverable, it is possible to reduce the construction cost.

Therefore, the method for constructing an underground structure using the above drainage box according to the present invention is designed so that the drainage during construction can be completely performed by adopting the following steps. The first step of embedding the drainage box manufactured in the factory in the kamaba which is provided everywhere in the construction site of the underground structure and providing the formwork for passing the drainage hose above the opening, and the above-mentioned water guide port and construction The second step of connecting the submersible pump in the body of the drainage box and connecting the guidewater channel provided to guide the groundwater at the site to the stove, and draining the groundwater introduced in the drainage box with the submersible pump. While constructing the underground slab, the third step is to build the underground slab and then close the water inlet to stop the entry of groundwater into the drainage box and collect the submersible pump stored in the drainage box. A fourth step of removing the formwork, a fifth step of removing the formwork, filling the inside of the drainage box with a backfill material, and surrounding the upper end of the tubular portion with a first water blocking material. Including There as.

In the above construction method, the third step includes the step of surrounding the upper opening surrounded by the formwork with the second waterproof material, whereby the groundwater from the periphery of the formwork is included. It is possible to completely prevent water leakage.

[0019] In the above construction method, the first water stopping material in the fifth step by employing a bentonite with swelling properties, some water leakage of groundwater from kiln field as fully prevented.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to the drawings. First, the drainage box will be described with reference to FIGS.

The drainage box 1 is composed of a container-shaped body 2 having a rectangular parallelepiped shape in appearance and a rectangular parallelepiped cylinder 3 provided on the upper portion of the body. Both the body 2 and the cylinder 3 are made of so-called sheet metal products assembled by welding steel plates together, and the upper part of the body inside the cylinder is notched to form an upper opening 4. The body 2 has a size capable of accommodating the submersible pump 5, and the above-described upper opening 4 has a size capable of taking in and out the pump.

Further, a circular water inlet 6 is provided on the upper portion of each side of the body portion 2 (only two locations are shown). The water guide port 6 is an inlet hole for introducing ground water into the drainage box 1 from a guide water channel described later, and is surrounded by the base of a cylindrical sleeve 7 in the body. The sleeve 7 has a base of a steel pipe fixed to the inside of the body 2 by welding, and a male screw portion 7a is carved at the tip.

The leading end of the sleeve 7 is covered with a water stop plug 8 so that the entry of groundwater from the water inlet 6 can be stopped. The water stop plug 8 is made of a steel cap nut, and the female screw portion 8a engraved on the opening side is the male screw portion 7 of the sleeve.
It can be screwed into a. The number of the water guide ports 6 is determined according to the actual condition of the construction site. Since the installation of unnecessary water inlets causes cost increase and water leakage, it is necessary to determine the number of water inlets corresponding to the actual situation.

Next, with reference to FIGS. 3 and 4, a construction method of an underground construction employing the above drainage box will be described by taking a construction site of a basement as an example.

FIG. 3 shows a process state of the construction of the basement using the drainage box 1 described above. In this figure, the construction of the underground slab 11 located at the lowest floor of the basement is completed, but in the following explanation, the process from the excavation of the ground to the completion of the underground slab and the underground wall will be explained. Will be explained in order.

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

Further, inside the steel sheet pile 12, a hump board 16 is provided to collect water leaking from the underground excavation surface downward along the steel sheet pile surface. The lower part of the chevron plate 16 is located between the steel sheet pile 12 and the drainage groove 13, and the upper part thereof is provided so as to have a height substantially matching the upper surface of a pressure-resistant concrete layer described later.

The drainage box 1 described above is embedded in the concave portion which will be the kettle 15 so that the water inlet 6 can be connected to the guide water passage 14. It should be noted that the drainage channel 13 and the guiding water channel 14 are provided with entrances for groundwater everywhere so that underground water can be collected and introduced into the drainage box 1.

Next, a water stop member 17 made of a bentonite sheet is attached around the cylindrical portion 3 of the drainage 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 between the outer peripheral portion of the cylindrical portion 3 and the mold 18. The formwork 18 allows the submersible pump 5 for drainage to be taken in and out, and also serves to pass the drainage hose 9. Formwork 1
The setting of 8 may be performed after the laying of the split stone layer 19 described later. The water blocking member 17 functions to prevent water leakage between the drainage box 1 and the form 18. The upper end of the mold 18 is installed so as to be located above the upper surface of the pressure-resistant concrete layer described later.

[0030] Next, the water pump 5 installed in the drainage box 1, collect open the water introduction port 6, remove the stop cock 8 the underground water to the drainage box. The collected groundwater is drained
The water can be drained to the ground via the water hose 9 (second
Process). The submersible pump 5 is provided so that ground water can be sucked in through a strainer 5b placed on the base 5a.

Next, a waterproof sheet (not shown) is laid on the bottom surface including the guiding water channel 14, and a crushed stone layer 19 is formed by laying medium-sized boulders on it. The upper surface of the split stone layer 19 has a height that substantially coincides with the upper end of the body portion 2 of the drainage box 1.

Next, bentonite powder is applied in a substantially triangular cross-section around the form 18 connecting the upper surface of the body 2 of the drainage box 1 and the intermediate position of the tube 3 to form the water stop 20. The water stop 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 discarded concrete layer 21 is formed on the waterproof sheet up to a height (about 160 mm) which is substantially coincident with the upper end of the drainage box 1. After the discarded concrete layer 21 is solidified, a waterproof plate 22 formed in an L-shaped cross section is arranged along the inner side of the hump plate 16, and a waterproof sheet 23 is further arranged inside thereof. The waterproof sheet 23 is provided so as to be double overlapped with the water blocking plate 22 in the range where the water blocking plate 22 is provided, and to be parallel to the steel sheet pile 12 in the range above the hood plate 16.

In this way, when the upper part of the discarded concrete layer 21 is covered with the waterproof sheet 23, the pressure resistant concrete layer 24 is then placed thereon. The pressure-resistant concrete layer 24 has a thickness of approximately 300 mm, and
It is cast on the whole of the underground floor except the part 8 (third step).

Here, the underground slab 11 along the steel sheet pile 12
Build the underground wall 25 on top. The underground wall 25 is formed by interposing the waterproof sheet 23 inside the steel sheet pile 12 so that ground water does not flow into the concrete being poured.

Next, while draining water by the submersible pump 5, put a hand into the drainage box 1 from the upper surface side of the underground slab 11 to cap all the sleeves 7 (stop cock).
8 is closed and the water guide port 6 is closed, and the entry of groundwater from the guide water channel 14 is stopped. Shortly after this, all the groundwater remaining in the drainage box 1 is drained by the submersible pump. Next, the submersible pump 5, strainer 5b, and hose 9 are pulled up and collected, and the form 18 is removed (fourth).
Process).

Next, as shown in FIG. 4, a backfill material 26 such as earth and sand or debris is filled in the empty drainage box 1 and tamped. The filling amount of the backfill material 26 is up to the vicinity of the upper end portion of the tubular portion 2. Next, a water blocking material 27 made of bentonite powder is put in the cavity formed inside the tubular part 3 to surround the perimeter and the upper part of the tubular part 3 to prevent leakage of groundwater from the drain box 1 ( Fifth step).

Next, the filling concrete portion 28 is provided by filling the cavities left above the submersible pump with solid concrete and solidifying it. Since the surface mortar layer 29 is formed on each upper surface of the pressure-resistant concrete layer 24 and the filled concrete portion 28, the filled concrete portion 28 filled in the cavity left above the drainage box 1 is filled.
The surface boundary between and 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 makes it easy to install the drainage structure by first installing the drainage box 1 on the stove 15. thing. Secondly, it is possible to stop the inflow of groundwater into the drain box by closing the water stopcock 8 after removing the formwork. Third, the submersible pump can be collected after removing the formwork. Fourthly, after filling the backfill material into the kamaba box 1 after collecting the submersible pump, the opening 4
By arranging bentonite around the ground, it is possible to prevent groundwater from leaking from the gap of the pressure-resistant concrete layer.

In this example, the shape of the drainage box is a rectangular parallelepiped, but the shape is not limited to this, and the material may be steel plate, synthetic resin or other substance. Further, although the water stopcock is described as a cap-like one, it may be rod-like, and the water stopcock may be engraved with a screw and the female thread is engraved on the opening side of the sleeve.

Further, the order of the steps of installing the formwork and forming the split stone layer and the discarded concrete layer does not affect the effect of the present invention even if it is contrary to the above description.

[0042]

The use of the drainage box according to the present invention makes it easy to install a rotary hook at a construction site of an underground structure, and also enables construction without leakage of groundwater.
Further, since the water guide port of the drainage box is openable and closable, the water in the drainage box can be eliminated by closing it at a predetermined construction point. Therefore, the submersible pump can be recovered after closing the water inlet. Along with this, even if the backfill material is filled after the pump is collected,
Since the water level will not rise from below, it is possible to backfill the kamaba with plenty of time.

Further, it is possible to prevent the leakage of groundwater from the periphery of the form by forming the water stop around the cylindrical portion of the drainage box during construction.

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

When the construction of an underground structure is carried out by adopting the present invention, since waterproofing measures are complete, the phenomenon of water filling in the concrete at the time of pouring concrete is eliminated, so that an underground structure made of high-quality concrete can be used. can get.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a drainage box.

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

FIG. 3 is a cross-sectional view showing an example of construction of an underground structure using a drainage box.

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

5A and 5B show a conventional example, where FIG. 5A is a plan view and FIG.
FIG. 7A is a sectional view taken along line BB of FIG.

[Explanation of symbols]

1 drainage box 2 torso 3 tube 4 Upper opening 5 submersible pumps 6 water inlet 8 stopcock 11 underground slabs 12 steel sheet pile 13 drains 14 Induction channel 15 Kamaba 18 formwork 20 Water stop 26 Backfill material 27 Water stop material (bentonite)

Claims (3)

(57) [Claims] 1. A body for accommodating a submersible pump, and this body
Section formed on the upper end of the
The upper opening that allows the pump to be taken in and out, and the
Multiple water inlets around the section and these water inlets
For kettles equipped with a water stopper that can be opened and closed from the inside
A drainage box is buried in a stake area provided at a key point of the construction site of an underground structure, and a formwork is provided around the cylinder section.
Process, installing the submersible pump in the body and opening the water guide, a second process, and proceeding with construction of an underground slab while draining the groundwater introduced into the drainage box with the submersible pump A step, a fourth step of closing the water inlet after the construction of the underground slab, collecting the submersible pump from the drain box and removing the formwork, and filling a backfill material into the drain box, A method of constructing an underground structure, comprising: a fifth step of forming a water blocking portion formed by surrounding a top surface of the backfill material and an upper end portion of the tubular portion with a water blocking material. 2. The method for constructing an underground structure according to claim 1, wherein the third step includes a step of surrounding the upper end of the trunk and the periphery of the formwork with a waterproof material. 3. The method for constructing an underground structure according to claim 1, wherein the water blocking material used in the fifth step is bentonite.