JPH07252846A - Pneumatic caisson - Google Patents

Abstract

PURPOSE:To prevent the collapse of the ground by providing an air passage on a pneumatic caisson having a pneumatic work room between an outer edge and an inner edge, discharging the pressure air in the work room between the inside and outside walls, and preventing the leakage of the high-pressure air from an outer edge port. CONSTITUTION:A proper number of shafts 9 each having an air lock 10 are provided in pneumatic work room 7 formed with an outer edge port 5 and an inner edge port 6 provided at the tip of an outside wall 2 and an inside wall 3 and a work room ceiling 4. The internal ground G is excavated manually or via machine power in the pneumatic work room 7, and a caisson main body 1 is gradually sunk. The excavated sediment is discharged onto the ground by a caisson bucket. When the pressure in the work room 7 becomes excessive or the caisson main body 1 is tilted, air is discharged from the shafts 9 so that high-pressure air is not leaked from a tip (a). The collapse or settlement of the ground can be prevented without damaging the peripheral ground G.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic caisson composed of a concrete structure buried in the ground and suitable for obtaining a large-scale underground space.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional annular pressure caisson of this type made of reinforced concrete.
Is an annular pressure air caisson body, and is provided with an outer annular side wall 101 and an inner annular side wall 102 located inside thereof. Further, 103 is a ceiling of the pneumatic working chamber, 104 is an outer annular blade, 1
Reference numeral 05 denotes an inner annular blade having the same shape as the outer annular blade 104,
The pneumatic working chamber 106 is defined by these.
In addition, G ₀ is the ground of the pneumatic working chamber 106.

However, as is well known, a pneumatic pipe (not shown) sends compressed air against the groundwater pressure corresponding to the depth of the excavated ground into the compressed air working chamber 106, which is under high pressure. The ground G ₀ is excavated by manpower or mechanical force, and the outer / inner annular blade openings 104 and 105 are sunk by the weight of the caisson, and the annular caisson body is subsequently sunk.

[0004]

However, in this case, it may not be possible to evenly excavate the ground G ₀ in order to evenly sink the outer and inner annular blade openings 104 and 105. In such a case, since the annular pressure air caisson main body 100 is slightly inclined, the pressure air inside the pressure air working chamber 106 is changed.
4 or the tip of the inner annular blade 105 may leak as indicated by an arrow a. Particularly, when leaking to the outer annular side wall 101 side, when the leak rises along the outer annular side wall 101. However, there is a problem in that the surrounding outer ground G may be damaged and may collapse or sink, which is extremely dangerous.

Also, when air leaks to the outer ground G, it leaks to the surrounding basement and tunnel, and at that time, the high-pressure air reacts with unoxidized minerals contained in the geology and becomes oxygen-deficient air, which is the basement. There was also a problem that it leaked to the etc. and caused a serious accident.

The present invention has been proposed in view of the above circumstances, and an object thereof is to prevent ground damage and collapse around the outer wall, and to prevent generation of oxygen-deficient air on the outer ground side. It is to provide a pneumatic caisson with a stop.

[0007]

According to the present invention, in a pneumatic caisson having an outer wall and an inner wall, and a space between them is a pneumatic working chamber, the compressed air in the pneumatic working chamber is provided below the inner wall. The above object is achieved by forming an air flow path that leaks to the inside of the inner wall.

[0008]

In the present invention, with the above-mentioned configuration,
High pressure air inside the compressed air work chamber is leaked to the outside from the inner blade opening.

[0009]

First Embodiment FIG. 1 shows a first embodiment of the present invention. 1 in the figure
Indicates an annular pressure air caisson body made of, for example, an annular reinforced concrete. Here, the term “annular” means that the cross section of the caisson body is closed, and the shape thereof may be circular, rectangular, or other shape, and when simply referred to as a pressure caisson in the present specification, it is confusing. In order to avoid the above, a shape other than a circular ring shape is used.

However, the above-mentioned annular pressure air caisson body 1 has an outer side wall 2 located outside and an inner side wall 3 located inside the outer side wall 2 with a space therebetween, and the inner side wall 3 below them. A work room ceiling 4 is provided between the outer wall 2 and the outer wall 2. In addition, the outer blade 2 has a downward extension line that has an outer blade opening 5
However, the inner blade openings 6 are also provided in a downward extension of the inner wall 3.

Reference numeral 7 is a compressed air working chamber defined by the outer and inner blade openings 5, 6, the working chamber ceiling 4, and the inner ground G ₁ below the working chamber, and 8 is an opening provided in the working chamber ceiling 4. , 9 is an appropriate number of shafts extending from the opening 8 to the ground side, 1
Reference numeral 0 is an airlock provided above the airlock.

The outer wall surface of the outer blade opening 5 has a step portion 5a which projects slightly outward from the outer wall surface of the outer wall 2. For example, when the annular pressure air caisson main body 1 is sunk, the outer wall surface and the outer ground G are separated. An outer gap 11 is formed therebetween, and a well-known lubricant such as bentonite solution is injected into this. Inner blade mouth 6
The inner wall surface of the inner wall 3 also has a step portion 6a, and protrudes similarly from the inner wall surface of the inner wall 3 to form an inner gap 11 ′ between the inner wall 11 and the inner ground G.
Are formed and are similarly filled with lubricant.

Further, in this case, in the present invention, the height H from the step 5a of the outer blade opening 5 to the lower end of the outer blade opening 5 is from the step 6a of the inner blade opening 6 to the lower end of the inner blade opening 6. It is lower than the height h by a. In other words, the length of the outer blade opening 5 is extended downward by a and is longer than that of the inner blade opening 6. The size of this a is optimally selected depending on the size of the annular pressure caisson body 1 . In addition, W is groundwater and W'is groundwater in the working room.

Therefore, for example, an annular pressure caisson body
1 is sunk, the pneumatic working chamber 7 is supplied with air through a compressor and an air supply pipe (not shown) installed on the ground, and the internal air pressure becomes equal to the head pressure up to the lower end of the inner blade opening 6. The internal ground G ₁ is excavated by manpower or mechanical force in the pneumatic working chamber 7, and the excavated soil is loaded in, for example, a caisson bucket (not shown), and the opening 8 is opened.
Then, it is discharged from the airlock 10 through the shaft 9 to the ground side under atmospheric pressure.

In these processes, the high-pressure air in the pneumatic working chamber 7 becomes excessively high in pressure, or, for example, when the annular pneumatic caisson body 1 is tilted, the lower end of the inner blade opening 6 which is shorter by the dimension a has a higher pressure. The high-pressure air leaks to the outside as shown by an arrow P and becomes an air flow path of air, rises along the inner side wall of the inner side wall 3 or leaks to the inner ground G ₁ side, and the lower end portion of the outer blade mouth 2 is Since it is always below the groundwater level, high-pressure air does not leak to the outer peripheral ground G from here, and the annular pressure caisson body 1 can be safely sunk, for example.

[0016]

[Embodiment 2] FIGS. 2A to 2C show a second embodiment of the present invention. In this embodiment, the height of the inner blade opening 6-1 is the same as that of the outer blade opening 5. And a plurality of notched recesses 6- serving as air flow paths around the entire lower portion of the inner blade opening 6-1.
2 are provided at appropriate intervals, and excess air in the compressed air working chamber 7 or, for example, an annular compressed air caisson body 1 is provided through the recess 6-2.
The feature is that the high pressure air P leaks to the inner ground G ₁ side when the vehicle tilts. Since other configurations and operations are similar to those of the above-described embodiment, the same members are denoted by the same reference numerals to avoid duplication of description, and the description thereof will be omitted. Further, the same effect can be obtained even if the pressure air caisson body has a shape other than a circular ring shape.

[0017]

According to the present invention configured as described above,
In the compressed air caisson, the high pressure air inside the compressed air work room was leaked to the inner peripheral ground side, so high pressure air did not leak from the outer blade mouth side, so the outer peripheral ground G was not damaged, and the surrounding ground collapse and subsidence Can be prevented.

Further, since the high-pressure air does not leak to the surrounding ground, oxygen-deficient air is not sent to the surrounding tunnel or basement, and the safety is improved.

[Brief description of drawings]

FIG. 1A is a vertical sectional view of a first embodiment of the present invention,
(B) The figure is the sectional view on the AA line same as the above.

FIG. 2 (a) is a longitudinal sectional view of a second embodiment of the present invention,
The figure (b) is a bottom view seen from the line BB in the above, and the figure (c) is a partial perspective view.

FIG. 3 shows a conventional example.

[Explanation of symbols]

 1 Pneumatic caisson main body 2 Outer side wall 3 Inner side wall 4 Working chamber ceiling 5 Outer blade openings 5a, 6a Steps 6,6-1 Inner blade opening 7 Pressure working room

Claims (1)

[Claims] 1. A compressed air caisson having an outer side wall and an inner side wall, and a space between them is a compressed air working chamber. Air for leaking compressed air inside the compressed air working chamber to the inside of the inner side wall below the inner side wall. A compressed air caisson characterized by forming a flow path.