Pneumatic caisson

Abstract

To provide a pneumatic caisson capable of enhancing the filling property of concrete after the concrete is filled in a working chamber of a caisson body.SOLUTION: The pneumatic caisson is a pneumatic caisson in which a working chamber 2 is installed in a lower part of a caisson body 1 and concrete is filled in the working chamber 2, and includes a pressure-resistant bag body 10 arranged in the working chamber 2 of the caisson body 1, and an injection hose 11, a force feed pump 13a, and a 13b for pressing a quick hardening filling material into the pressure-resistant bag body 10 after filling the concrete in the working chamber 2 of the caisson body 1. The quick-hardening filling material is pressed into the pressure-resistant bag body 10 by an injection hose 11 and force feed pumps 13a and 13b to pressurize the filled concrete.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pneumatic caisson, for example, in which a working chamber is installed below the caisson body, and concrete is filled into this working chamber after the caisson is installed. [Background technology]

[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, transmitting force evenly to the foundation ground and preventing groundwater from entering the caisson body. For this reason, the filling ability of the concrete filling is important. The general filling method is a combination of gravity flow of concrete and air blow suction, but due to the difficulty of filling, mortar with excellent fluidity or high-flow concrete is filled in the area directly below the work chamber slab.

[0003] Furthermore, since it has been difficult to visually check whether a tank has been filled, there have been cases where a web camera has been used to check whether a tank has been filled (Non-Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-68367 [Non-patent literature]

[0005] [Non-Patent Document 1] Visualization of buried concrete in pneumatic caisson construction, Concrete Engineering, Vol. 53, No. 5, May 2015 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it is believed that conventional construction methods cannot completely prevent the occurrence of voids due to self-sinking of the filler concrete or the formation of partial air pockets directly below the work chamber slab.

[0007] Incidentally, in the method of pouring backfill concrete described in Patent Document 1, the running rails of the excavator are left in the working chamber when pouring the backfill concrete, so an attempt is made to improve filling properties by using an AE water-reducing agent retarding admixture.

[0008] However, this casting method uses admixtures to increase the fluidity of the filled concrete, which makes it susceptible to the effects of concrete temperature. In addition, if the amount added is too small, the desired fluidity effect cannot be achieved, resulting in a deterioration in the quality of the concrete.

[0009] The present invention was made in consideration of the above circumstances, and aims to provide a pneumatic caisson that can improve the filling properties of concrete after it is filled into the working chamber of the caisson body. [Means for solving the problem]

[0010] In order to solve the above problems, the invention described in claim 1 of the present invention is a pneumatic caisson in which a work chamber is installed below the caisson body and concrete is poured into the work chamber, characterized in that it comprises a pressure-resistant bag body arranged in the work chamber of the caisson body, and a pressurizing means for pressurizing a rapid-hardening filler into the pressure-resistant bag body after pouring concrete into the work chamber of the caisson body, and is configured so that the poured concrete is pressurized by pressurizing the rapid-hardening filler into the pressure-resistant bag body by the pressurizing means. Furthermore, the invention described in claim 2 of the present invention is characterized in that, in addition to the configuration described in claim 1, the pressure-resistant bag body is made of synthetic fiber and is arranged on the ceiling slab inside the work chamber.

[0011] Furthermore, the invention described in claim 3 of the present invention is characterized in that, in addition to the configuration described in claim 2, the press-in means is provided with a plurality of press-in hoses that penetrate the ceiling slab and press the rapid-hardening filler into the pressure-resistant bag body.

[0012] Furthermore, the invention described in claim 4 of the present invention is characterized in that, in addition to the configuration described in claim 1, an opening for installing equipment is formed in the ceiling slab, and the pressure-resistant bag body is continuously arranged in a circular ring shape on the ceiling slab so as to surround the opening of the work chamber.

[0013] Furthermore, the invention as set forth in claim 5 of the present invention is characterized in that, in addition to the configuration as set forth in claim 1, the rapid-hardening filler pressurized into the pressure-resistant bag body is a grout material. [Effects of the Invention]

[0014] According to the invention described in claim 1 of the present invention, the poured concrete is pressurized by pressing a rapid-hardening filler into a pressure-resistant bag body using a pressing means, thereby making it possible to improve the filling ability of the concrete after it is poured into the working chamber of the caisson body.

[0015] Furthermore, according to the invention described in claim 2 of the present invention, in addition to the effects of the invention described in claim 1, the pressure-resistant bag body is made of synthetic fiber and is arranged on the ceiling slab inside the workroom where air pockets are likely to occur, so the concrete can be packed in an over-dense state, and air pockets can be effectively compressed to make them into tiny spaces.

[0016] Furthermore, according to the invention described in claim 3 of the present invention, in addition to the effect described in claim 1, the press-in means has a plurality of press-in hoses that penetrate the ceiling slab and press the rapid-hardening filler into the pressure-resistant bag body, so that even if one of the plurality of press-in hoses is damaged, the rapid-hardening filler can be reliably pressed into the pressure-resistant bag body, thereby improving reliability.

[0017] Furthermore, according to the invention described in claim 4 of the present invention, in addition to the effects of the invention described in claim 1, the pressure-resistant bag body is continuously arranged in a circular ring shape on the ceiling slab so as to surround the opening of the work chamber, so that the contact area of ​​the pressure-resistant bag body with the concrete after pouring is increased, making it possible to make the concrete even more densely packed.

[0018] Furthermore, according to the invention described in claim 5 of the present invention, in addition to the effects of the invention described in claim 4, the rapid-hardening filler pressed into the pressure-resistant bag body is a grout material, which has high fluidity and makes it possible to compress air pockets more effectively and turn them into tiny spaces. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is an enlarged cross-sectional view showing the main parts of a pneumatic caisson according to one embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing the pneumatic caisson of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[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, and Fig. 2 is a plan view showing the pneumatic caisson of Fig. 1.

[0022] The pneumatic caisson (hereinafter referred to as the caisson body) 1 of this embodiment is used in the construction of a pneumatic caisson method. This pneumatic caisson method is a construction method in which a box body made of, for example, reinforced concrete is constructed on the ground in advance, with a work chamber surrounded by a cutting edge at the bottom, and then an excavator is used to excavate the box body in this work chamber, and the box body is then constructed in layers one by one, and the structure is installed in a predetermined position.

[0023] As shown in Figures 1 and 2, a caisson body 1 of this embodiment has a work chamber 2 installed at the bottom. This work chamber 2 is surrounded by a cutting edge section 3 and a ceiling slab 4. After excavation is complete, concrete is filled into the work chamber 2 to form backfill concrete 5. This backfill concrete 5 is constructed to integrate with the caisson body 6, transmit force uniformly to the foundation ground, and prevent groundwater from seeping into the caisson body 6.

[0024] A circular shaft hole 4a is formed in the center of the ceiling slab 4 for installing two pieces of equipment: a manlock and a material lock. The two pieces of equipment are a manlock used when workers enter and exit the workroom 2, and a material lock used when transporting excavated soil from the workroom 2 to the ground and when transporting materials in and out.

[0025] Two pouring pipes 7 are arranged facing each other on the ceiling slab 4 near the shaft hole 4a. These pouring pipes 7 are used to fill the work chamber 2 with fresh concrete from, for example, a concrete mixer truck (not shown) on the ground, to form the fill concrete 5 inside the work chamber 2. In addition, a plurality of exhaust pipes 8 are arranged at regular intervals around the periphery of the ceiling slab 4 to exhaust air from the work chamber 2 when fresh concrete is poured inside the work chamber 2.

[0026] As shown in Figure 1, a synthetic fiber pressure-resistant bag 10 is disposed in contact with the underside of the ceiling slab 4 in the work chamber 2. Specifically, the pressure-resistant bag 10 is disposed continuously in a circular ring shape on the ceiling slab 4 so as to surround the shaft hole 4a of the work chamber 2. Immediately after the filler concrete 5 is poured into the work chamber 2, a rapid-hardening filler, such as grout, is pressed into the pressure-resistant bag 10. The synthetic fiber is highly flexible and has excellent gap-filling properties, and synthetic resins such as polyester and nylon are used for this purpose.

[0027] The pressure-resistant bag body 10 is installed over the entire surface of the ceiling slab 4, except for areas where it cannot be installed, such as the pouring pipe 7, exhaust pipe 8, shaft hole 4a, etc.

[0028] Two sets of injection hoses (pressure-insertion means, pressurization hoses) 11, each consisting of two hoses, are connected to the pressure-resistant bag 10, and the connection portions of these two sets of injection hoses 11 are arranged at symmetrical positions on the pressure-resistant bag 10. These injection hoses 11 are connected to pressure-feed pumps 13a and 13b, which serve as pressure-insertion means of different systems. These pressure-feed pumps 13a and 13b are connected to a grout material tank 15 via pipes 14a and 14b, respectively.

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

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

[0031] First, when pouring the ceiling slab 4 of the work chamber 2, two sets of injection hoses 11 are buried. Then, when pouring the filler concrete 5, pressure-resistant bags 10 are connected to the two sets of injection hoses 11. Here, the pressure-resistant bags 10 are fixed to the underside of the ceiling slab 4 of the work chamber 2 with a fixing member such as strong tape. Furthermore, each set of the two sets of injection hoses 11 is connected to pressure pumps 13a, 13b on separate systems. These pressure pumps 13a, 13b are connected in advance to a grout tank 15 via pipes 14a, 14b.

[0032] Next, to form the filler concrete 5, fresh concrete is poured into the work chamber 2 from a concrete mixer truck (not shown) on the ground through the pouring pipe 7. After filling the work chamber 2 with the filler concrete 5, the air supply to the work chamber 2 by the air supply means (not shown) for pressurizing the work chamber 2 is stopped, and the pressure pumps 13a and 13b are driven. The grout contained in the grout tank 15 is then forced into the pressure-resistant bag 10 through the pipes 14a and 14b and the injection hose 11. When the injection pressure of the grout material by the pressure pumps 13a and 13b reaches a preset value of 3.0 MPa, the operation of the pressure pumps 13a and 13b is stopped, and the injection of the grout material is terminated. The set pressure of the grout material by the pressure pumps 13a and 13b is not limited to the above pressure and may be changed as appropriate depending on the conditions.

[0033] Incidentally, in a typical pneumatic caisson, although the filling ability of the filler concrete 5 is important, since the construction site is an enclosed space under pressurized air, it is extremely difficult to fill the final filling point, directly below the ceiling slab 4 of the work chamber 2, and it is also difficult to visually confirm the filling. For this reason, with typical construction methods, it is not possible to completely prevent the occurrence of voids due to self-sinking of the filler concrete 5 or the formation of air pockets directly below the ceiling slab 4.

[0034] In this embodiment, after concrete has been poured into the work chamber 2, grout is pressed into the pressure-resistant bag 10 for the filler concrete 5, and pressure is applied in the direction of the arrow in Figure 1, thereby making the filler concrete 5 into an over-packed state. As a result, it is possible to suppress the occurrence of voids due to self-settling of the concrete, and to compress air pockets into tiny spaces.

[0035] According to this embodiment, the poured concrete is pressurized by injecting grout material as a rapid-hardening filler into the pressure-resistant bag body 10 using a pressing means consisting of two injection hoses 11 and pressure pumps 13a, 13b, which makes it possible to improve the filling ability of the concrete after it is poured into the working chamber 2 of the caisson body 1, thereby shortening the construction period and reducing equipment costs.

[0036] Furthermore, 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 workroom 2 where air pockets are likely to occur, so that the concrete can be packed densely, and the air pockets can be effectively compressed to make them into tiny spaces.

[0037] Furthermore, according to this embodiment, the pressing means has a plurality of injection hoses 11 penetrating the ceiling slab 4 for pressing the grout material into the pressure-resistant bag body 10, so that even if one of the plurality of injection hoses 11 is damaged, the grout material can be reliably pressed into the pressure-resistant bag body 10, thereby improving reliability.

[0038] In addition, according to this embodiment, the pressure-resistant bag body 10 is continuously arranged in a circular ring shape on the ceiling slab 4 so as to surround the shaft hole 4a of the work chamber 2, so that the contact area of ​​the pressure-resistant bag body 10 with the concrete after pouring is increased, allowing the concrete to be packed even more densely.

[0039] Furthermore, according to this embodiment, the rapid-hardening filler material pressed into the pressure-resistant bag body 10 is a grout material, which has high fluidity and makes it possible to compress air pockets more effectively and turn them into tiny spaces.

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

[0041] [Another embodiment 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 embodied in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. This embodiment is included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0042] In the above embodiment, the pressure-resistant bags 10 are arranged continuously in a circular ring shape on the ceiling slab 4 so as to surround the shaft hole 4a of the work chamber 2, but this is not limiting and a plurality of arc-shaped pressure-resistant bags 10 may be arranged in a circular ring shape. The pressure-resistant bags 10 may be of any shape as long as they can be filled with a rapid-hardening filler and can pressurize the concrete poured in the work chamber 2.

[0043] Furthermore, in the above embodiment, an example was described in which the pressure-resistant bag body 10 was arranged in a position where it abuts against the underside of the ceiling slab 4, but it may be arranged in any location where air pockets occur.

[0044] Furthermore, in the above embodiment, an example has been described in which grout is used as the rapid-hardening filler, but other materials than grout may also be used as long as they have rapid hardening properties and high fluidity.

[0045] The above embodiment has been described as an example in which the caisson is circular in plan view, but it can also be applied to caissons of any other shape, such as square, elliptical, etc. In addition, the above embodiment has been described as an example in which two shaft holes 4 are provided, but the number can be increased if the caisson is larger, and can be decreased if the caisson is smaller. [Explanation of symbols]

[0046] 1 Pneumatic caisson (caisson body) 2. Workroom 3 Blade mouth part 4 Ceiling slab 4a Shaft hole 5. Filler concrete 6 Caisson body 7 Casting pipe 8 exhaust pipe 10 Pressure-resistant bag 11 Injection hose (pressure-in means, press-in hose) 13a, 13b Pressure pump (pressure-in means) 14a, 14b Piping 15 Grout tank 16 Opening and closing valve

Claims

1. A pneumatic caisson in which a work chamber is installed at the bottom of the caisson body and concrete is poured into the work chamber, A pressure-resistant bag body disposed in the working chamber of the caisson body; and a press-in means for pressurizing a rapid-hardening filler into the pressure-resistant bag body after pouring concrete into the working chamber of the caisson body, A pneumatic caisson characterized in that the poured concrete is pressurized by pressing the rapid-hardening filler into the pressure-resistant bag body using the pressing means.

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

3. 3. The pneumatic caisson according to claim 2, wherein the press-in means comprises a plurality of press-in hoses that penetrate the ceiling slab and pressurize the rapid-hardening filler into the pressure-resistant bag body.

4. The pneumatic caisson described in claim 2, characterized in that an opening for installing equipment is formed in the ceiling slab, and the pressure-resistant bag body is arranged continuously in a circular ring shape on the ceiling slab so as to surround the opening of the workroom.

5. 5. A pneumatic caisson according to claim 1, wherein the rapid hardening filler material pressed into the pressure-resistant bag is a grout material.

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