Pneumatic caisson

Abstract

Provided is a pneumatic caisson capable of enhancing the fillability of concrete after the working chamber of the caisson body is filled with concrete. 【Solution means】The pneumatic caisson is a pneumatic caisson in which a working chamber 2 is installed at the lower part of the caisson body 1, and the working chamber 2 is filled with concrete. The pneumatic caisson is provided with a pressure-resistant bag body 10 disposed in the working chamber 2 of the caisson body 1, an injection hose 11 for injecting a quick-hardening filler into the pressure-resistant bag body 10 after the working chamber 2 of the caisson body 1 is filled with concrete, and pressure pumps 13a, 13b. The injection hose 11 and the pressure pumps 13a, 13b are configured to pressurize the filled concrete by injecting the quick-hardening filler into the pressure-resistant bag body 10.

Description

Technical Field

[0001] The present invention relates to a pneumatic caisson in which a work chamber is installed, for example, at the lower part of a caisson body, and after the caisson is sunk, the work chamber is filled with concrete.

Background Art

[0002] Generally, in the pneumatic caisson method, after excavation is completed, the work chamber is filled with concrete to integrate it with the caisson body, transmit force uniformly to the foundation ground, and prevent groundwater from entering the caisson body. For this reason, the fillability of the in-filled concrete is important. A general filling method is the combined use of the natural flow of concrete and air blow suction, but due to the difficulty of fillability, mortar or high-fluidity concrete with excellent fluidity is filled in the part directly below the work chamber slab.

[0003] In addition, conventionally, since it is difficult to confirm filling visually, there is also a case (Non-Patent Document 1) where filling confirmation is performed using a web camera.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, with the conventional construction method, it is considered that the generation of voids due to the self-settlement of the embedded concrete and the partial air accumulation directly under the working chamber slab cannot be completely prevented.

[0007] By the way, in the method for placing embedded concrete described in Patent Document 1, when placing the embedded concrete, since the traveling rails of the excavator are left in the working chamber, an AE water reducer retarder type admixture is used to improve the filling property.

[0008] However, in this placing method, since an admixture is used to increase the fluidity of the embedded concrete, it is easily affected by the concrete temperature, and when the addition amount is small, a desirable fluidity effect cannot be obtained, and there is a problem that the quality of the concrete deteriorates.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a pneumatic caisson capable of enhancing the filling property of concrete after filling the working chamber of the caisson body with concrete.

Means for Solving the Problems

[0010] In order to solve the above problems, the invention according to claim 1 of the present invention is a pneumatic caisson in which a working chamber is installed at the lower part of the caisson body, and concrete is placed in the working chamber, and a pressure-resistant bag body disposed in the working chamber of the caisson body, and pressure-injection means for pressure-injecting a quick-hardening filler into the pressure-resistant bag body after placing concrete in the working chamber of the caisson body, and is configured to pressurize the placed concrete by pressure-injecting the quick-hardening filler into the pressure-resistant bag body by the pressure-injection means. Further, the invention according to claim 2 of the present invention is characterized in that, in addition to the configuration according to claim 1, the pressure-resistant bag body is made of synthetic fiber and is disposed on the ceiling slab in the working chamber.

[0011] Further, the invention according to claim 3 of the present invention is characterized in that, in addition to the configuration according to claim 2, a plurality of pressure injection hoses for injecting the rapid hardening filler into the pressure-resistant bag are provided penetrating through the ceiling slab.

[0012] Further, the invention according to claim 4 of the present invention is characterized in that, in addition to the configuration according to claim 1, an opening for installing outfitting equipment is formed in the ceiling slab, and the pressure-resistant bag is continuously arranged in an annular shape so as to surround the opening of the working chamber in the ceiling slab.

[0013] Further, the invention according to claim 5 of the present invention is characterized in that, in addition to the configuration according to claim 1, the rapid hardening filler injected into the pressure-resistant bag is a grout material.

Advantages of the Invention

[0014] According to the invention described in claim 1 of the present invention, by injecting the rapid hardening filler into the pressure-resistant bag by the pressure injection means, and configuring to pressurize the placed concrete, it is possible to improve the filling property of the concrete after placing the concrete in the working chamber of the caisson body.

[0015] Further, according to the invention described in claim 2 of the present invention, in addition to the effect of the invention described in claim 1, since the pressure-resistant bag is made of synthetic fiber and is arranged on the ceiling slab in the working chamber where air pockets are likely to occur, the concrete can be in a state of over-dense filling, and it is possible to effectively compress the air pockets into minute spaces.

[0016] Further, according to the invention described in claim 3 of the present invention, in addition to the effect described in claim 1, since a plurality of pressure injection hoses for injecting the rapid hardening filler into the pressure-resistant bag are provided penetrating through the ceiling slab, even if one of the plurality of pressure injection hoses is damaged, the rapid hardening filler can be surely injected into the pressure-resistant bag, and the reliability can be improved.

[0017] Further, according to the invention described in claim 4 of the present invention, in addition to the effects of the invention described in claim 1, since the pressure-resistant bag body is continuously arranged in an annular shape so as to surround the opening of the working chamber in the ceiling slab, the contact area of the pressure-resistant bag body with the concrete after placement becomes large, and the concrete can be made into an even more densely packed state.

[0018] Further, according to the invention described in claim 5 of the present invention, in addition to the effects of the invention described in claim 4, since the quick-setting filling material injected into the pressure-resistant bag body is a grout material, it has high fluidity and can more effectively compress air pockets into minute spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0019]

Figure 1

Figure 2

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0021] [One Embodiment] FIG. 1 is an enlarged cross-sectional view showing a main part of a pneumatic caisson according to an embodiment of the present invention. FIG. 2 is a plan view showing the pneumatic caisson of FIG. 1.

[0022] Note that the pneumatic caisson (hereinafter referred to as the caisson body) 1 of the present embodiment is used for the construction of the pneumatic caisson method. This pneumatic caisson method is a method in which, for example, a reinforced concrete casing having a working chamber surrounded by a blade edge portion at the bottom is constructed on the ground in advance, and after excavating using an excavator in this working chamber and sinking the casing, layers of the casing are sequentially constructed to install a structure at a predetermined position.

[0023] As shown in FIGS. 1 and 2, in the caisson body 1 of the present embodiment, a working chamber 2 is installed at the lower part. This working chamber 2 is formed by being surrounded by a blade edge portion 3 and a ceiling slab 4. After the excavation is completed, the working chamber 2 is filled with concrete to form the in-filled concrete 5. This in-filled concrete 5 is constructed to integrate with the caisson body 6, transmit force uniformly to the foundation ground, and prevent the intrusion of groundwater into the caisson body 6.

[0024] At the center of the ceiling slab 4, a circular through shaft hole 4a for installing two outfitting facilities, a manhole and a material lock, is formed. The above two outfitting facilities include a manhole used when workers enter and exit the working chamber 2, and a material lock used when excavated earth and sand are carried out to the ground from the working chamber 2 or when materials are carried in and out.

[0025] On the ceiling slab 4 near the shaft hole 4a, two placing pipes 7 are arranged so as to face each other. These placing pipes 7 are filled with fresh concrete from, for example, a concrete mixer truck on the ground (not shown) into the working chamber 2 in order to form the in-filled concrete 5 in the working chamber 2. Further, on the outer peripheral side of the ceiling slab 4, a plurality of exhaust pipes 8 for discharging the air in the working chamber 2 are arranged at regular intervals in the circumferential direction when fresh concrete is placed in the working chamber 2.

[0026] As shown in FIG. 1, on the ceiling slab 4 in the working chamber 2, a pressure-resistant bag body 10 made of synthetic fiber is arranged so as to abut on the lower surface. Specifically, this pressure-resistant bag body 10 is continuously arranged in an annular shape so as to surround the shaft hole 4a of the working chamber 2 on the ceiling slab 4. Immediately after the in-filled concrete 5 is placed in the working chamber 2, a grout material, for example, is press-fitted into the pressure-resistant bag body 10 as a rapid-hardening filling material. As the above synthetic fiber, one having high flexibility and excellent gap filling property is used, and for example, synthetic resins such as polyester and nylon are used.

[0027] The pressure-resistant bag body 10 is installed over the entire ceiling slab 4, excluding parts such as the placing pipe 7, the exhaust pipe 8, and the shaft hole 4a where it cannot be laid.

[0028] Two sets of two injection hoses (pressing means, press-in hoses) 11 are respectively connected to the pressure-resistant bag body 10, and the connection parts of these two sets of two injection hoses 11 are respectively arranged at symmetric positions in the pressure-resistant bag body 10. These injection hoses 11 are respectively connected to pressure feed pumps 13a, 13b as pressing means with different systems. These pressure feed pumps 13a, 13b are respectively connected to the grout material tank 15 via pipes 14a, 14b.

[0029] Then, by driving each of the pressure feed pumps 13a, 13b, the grout material accommodated in each grout material tank 15 is pressed into and filled in the pressure-resistant bag body 10 through the pipes 14a, 14b and the injection hoses 11. Each of the two sets of two injection hoses 11 is provided with an on-off valve 16.

[0030] Next, the operation of the pneumatic caisson 1 according to the present embodiment will be described.

[0031] First, when the ceiling slab 4 of the workroom 2 is placed, two sets of two injection hoses 11 are embedded. Then, when the in-filled concrete 5 is placed, the pressure-resistant bag body 10 is connected to the two sets of two injection hoses 11. Here, the pressure-resistant bag body 10 is fixed to the lower surface of the ceiling slab 4 of the workroom 2 by a fixing member such as a strong tape. Also, each of the two sets of two injection hoses 11 is respectively connected to pressure feed pumps 13a, 13b with different systems for each set. These pressure feed pumps 13a, 13b are previously connected to the grout material tank 15 via pipes 14a, 14b.

[0032] Next, to form the infill concrete 5, fresh concrete is filled into the work chamber 2 from a concrete mixer truck on the ground (not shown) through the placing pipe 7. After the infill concrete 5 is completely filled into the work chamber 2, the air supply into the work chamber 2 by an air supply means (not shown) for maintaining under pressure is interrupted, and each of the pressure pumps 13a and 13b is driven. Then, the grout material stored in the grout tank 15 is pressure-fed through the pipes 14a and 14b and the injection hoses 11 into the pressure-resistant bag 10 and filled. When the injection pressure of the grout material by each of the pressure pumps 13a and 13b reaches the preset 3.0 MPa, the driving of the pressure pumps 13a and 13b is stopped to finish the injection of the grout material. Here, the set pressure of the grout material by each of the pressure pumps 13a and 13b is not limited to the above pressure and may be appropriately changed according to the conditions.

[0033] By the way, in a general pneumatic caisson, although the fillability of the infill concrete 5 is important, since the construction site is an enclosed space under pressure, it is extremely difficult to fill the area directly below the ceiling slab 4 of the work chamber 2, which is the final filling location, and it is also difficult to confirm the filling visually. Therefore, with a general construction method, it is impossible to completely prevent the generation of voids due to the self-settling of the infill concrete 5 and the air accumulation directly below the ceiling slab 4.

[0034] In this embodiment, by pressure-feeding the grout material into the pressure-resistant bag 10 and pressurizing it in the direction of the arrow in FIG. 1 with respect to the infill concrete 5 after the placement of the concrete into the work chamber 2 is completed, the infill concrete 5 can be brought into a state of over-compacted filling. As a result, it is possible to suppress the generation of voids due to the self-settling of the concrete and to compress the air accumulation into a minute space.

[0035] Thus, according to this embodiment, by injecting grout material as a rapid-hardening filling material into the pressure-resistant bag body 10 by means of the injection means composed of two injection hoses 11 and the pressure pumps 13a and 13b, and configuring it to pressurize the placed concrete, it becomes possible to improve the filling property of the concrete after placing the concrete in the working chamber 2 of the caisson body 1, shorten the construction period, and reduce the equipment cost.

[0036] Moreover, according to this embodiment, the pressure-resistant bag body 10 is made of synthetic fiber and is disposed on the ceiling slab 4 in the working chamber 2 where air pockets are likely to occur. Therefore, the concrete can be in an over-dense filling state, and it is possible to effectively compress the air pockets into minute spaces.

[0037] Furthermore, according to this embodiment, since a plurality of injection hoses 11 for injecting grout material into the pressure-resistant bag body 10 penetrate through the ceiling slab 4, even if one of the plurality of injection hoses 11 is damaged, the grout material can be surely injected into the pressure-resistant bag body 10, thereby enhancing the reliability.

[0038] Also, according to this embodiment, since the pressure-resistant bag body 10 is continuously arranged in an annular shape so as to surround the shaft hole 4a of the working chamber 2 in the ceiling slab 4, the contact area of the pressure-resistant bag body 10 with respect to the placed concrete becomes large, and the concrete can be made into an even more over-dense filling state.

[0039] In addition, according to this embodiment, since the rapid-hardening filling material injected into the pressure-resistant bag body 10 is grout material, it has high fluidity and can further effectively compress the air pockets into minute spaces.

[0040] In this embodiment, an example in which two sets of one pair of injection hoses 11 are provided has been described. However, based on the shape and size of the caisson, the number of sets and the number of the injection hoses 11 may be appropriately increased or decreased.

[0041] [Other Embodiments of the Invention] Although one embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. This embodiment is included in the scope and gist of the invention, as well as in the invention described in the claims and its equivalent scope.

[0042] In the above embodiment, the pressure-resistant bag body 10 is continuously arranged in an annular shape so as to surround the shaft hole 4a of the working chamber 2 in the ceiling slab 4. However, the present invention is not limited to this, and a plurality of arc-shaped pressure-resistant bag bodies 10 may be arranged in an annular shape. And the pressure-resistant bag body 10 may have any shape as long as it can be filled with a quick-setting filler and can pressurize the concrete placed in the working chamber 2.

[0043] In the above embodiment, an example in which the pressure-resistant bag body 10 is arranged at a position in contact with the lower surface of the ceiling slab 4 has been described. However, as long as it is a place where an air pocket is generated, it may be arranged at any place.

[0044] Furthermore, in the above embodiment, an example in which a grout material is used as the quick-setting filler has been described. However, as long as it is a material with high quick-setting property and fluidity other than this, a material other than the grout material may be used.

[0045] And the above embodiment has described an example applied to a caisson having a circular shape in plan view. However, in addition to this, it can be applied to caissons of any shape such as square, elliptical, etc. In addition, in the above embodiment, an example in which two shaft holes 4 are provided has been described. However, as the size of the caisson becomes larger, the number can be further increased, while as the size of the caisson becomes smaller, the number can be further decreased.

Explanation of reference numerals

[0046] 1 Pneumatic caisson (caisson body) 2 Working chamber 3 Cutting edge part 4 Ceiling slab 4a Shaft hole 5 In-filled concrete 6 Caisson body 7 Placing pipe 8 Exhaust pipe 10 Pressure-resistant bag body 11 Injection hose (press-fitting means, press-fitting hose) 13a, 13b Pressure pump (press-fitting means) 14a, 14b Pipe 15 Grout material tank 16 On-off valve

Claims

1. A pneumatic caisson in which a working chamber is installed at the lower part of the caisson body and concrete is placed in the working chamber, a pressure-resistant bag body disposed in the working chamber of the caisson body, and pressing means for pressing a quick-setting filler into the pressure-resistant bag body after placing concrete in the working chamber of the caisson body, The pneumatic caisson is characterized in that the placed concrete is pressurized by pressing the quick-setting filler into the pressure-resistant bag body by the pressing means.

2. The pneumatic caisson according to claim 1, wherein the pressure-resistant bag body is made of synthetic fiber and is disposed on a ceiling slab in the working chamber.

3. The pneumatic caisson according to claim 2, wherein a plurality of injection hoses for injecting the quick-setting filler into the pressure-resistant bag body penetrate through the ceiling slab.

4. An opening for installing outfitting equipment is formed in the ceiling slab, and the pressure-resistant bag body is continuously arranged in an annular shape so as to surround the opening of the working chamber in the ceiling slab. The pneumatic caisson according to claim 2.

5. The pneumatic caisson according to any one of claims 1 to 4, wherein the quick-setting filler pressed into the pressure-resistant bag body is a grout material.

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