JPH0441818A - Ring-shaped pressure air caisson - Google Patents

Abstract

PURPOSE:To prevent damage and collapse of the surrounding ground by providing an outer ring-form cutting edge in the lower part of the outer ring-form side wall of a ring-form pressure caisson, and giving this outer cutting edge such a length as extending downward exceeding the length of the inner ring- form cutting edge of an inner ring-form side wall. CONSTITUTION:An inner ring-form side wall 3 is formed inside of the outer ring-form side wall 2 of the body 1 of ring-form pressure caisson, wherein a certain gap is reserved in between. The height H from a step 5a of an outer ring-form cutting edge 5 provided in the lower part of this outer side wall 2 till the bottom of the cutting edge 5 shall be smaller by (a) than the height (h) from a step 6a of an inner ring-form cutting edge 6 provided in the lower part of the inner side wall 3 till the bottom of the cutting edge 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an annular pneumatic caisson made of a concrete structure buried underground and suitable for obtaining a large-scale underground space.

(Prior Art) Fig. 3 shows a conventional annular pressure caisson of this type made of reinforced concrete. In the figure, 100 is the main body of the annular pressure caisson, which includes an outer annular side wall 101 and an inner annular side located inside the annular side wall 101. g1102. Also, 103
Reference numeral 104 denotes the ceiling of the pressurized air work chamber, 104 indicates an outer annular cutting edge, and 105 indicates an inner annular cutting edge having approximately the same shape as the outer annular cutting edge 104. A pressure air working chamber 106 is defined by these.

In addition, Go is the ground of the pressurized air work chamber 106 part.

As is well known, pressurized air that counters the groundwater pressure corresponding to the depth of the excavated ground is sent into the pressurized air work chamber 106 through an air pipe (not shown), creating a high pressure environment. is excavated by manual or mechanical power, and the outer and inner annular cutting holes 105.10 are excavated by the weight of the caisson.
4 is submerged, and eventually the annular caisson body is submerged.

(However, in this case, the outer and inner annular cutting edges 105.10
There are cases where it is not possible to excavate the ground Go evenly in order to make the ground Go sink evenly. In such a case, the annular pressure caisson main body 100 is slightly tilted, so that the pressure inside the pressure work chamber (106) is transferred to the outer annular cutting port (104) or the inner annular cutting port (104).
Air may leak from the tip of 05) as shown by arrow a, especially when the air leaks toward the outer annular m wall (101), and when the leak rises along the outer annular side wall (101). 111, which is extremely dangerous as it can damage the surrounding outer ground G and cause it to collapse or subside! was there.

In addition, when air leaks to the outer ground G, it leaks into surrounding basements and tunnels, and at that time, the high-pressure air reacts with unoxidized minerals contained in the geology, becoming oxygen-deficient air and leaking into basements, etc. However, there was also the issue that it could lead to serious accidents.

The present invention was proposed in view of the above, and its purpose is to prevent ground damage, collapse, etc. around the outer annular side wall 101, and to prevent the generation of oxygen-deficient air on the outer peripheral ground side. The designed annular pressure caisson is in service with G1.

(Means for Solving Illl) In the present invention, in an annular pressure caisson having an outer annular side wall and an inner annular side wall, the length of the outer annular cutting hole provided at the lower part of the outer annular side wall is determined by The above objective is achieved by extending the length of the cutting edge downwardly for a longer period than the length of the inner annular cutting edge.

Further, the above object is achieved by having the lengths of the respective cutting edges of the outer and inner annular side walls being approximately the same, and by providing a recessed portion at the lower part of the inner annular cutting edge.

(Function) In the present invention, by configuring as described above, the high pressure air inside the annular working chamber leaks to the outside from the inner annular cutting edge portion.

(Example 1) Fig. 1 shows a first embodiment of the present invention. (1) in Fig. 1 shows an annular pressurized air caisson body made of reinforced concrete and having an annular shape, for example. Here, annular means: It means a caisson whose cross section is closed, and the shape may be circular, square, or other shapes.

Therefore, the annular pressure caisson main body (1) is located on the outer annular side! (2) and an inner annular side wall (3) located at a distance therebetween, and below these, the inner annular side wall (3) and the outer annular side! ! ! A work room ceiling (4) is provided between the work chamber and the work chamber (2). Further, an outer annular cutting edge (5) is provided on the downward extension of the outer annular side wall (2), and an inner annular cutting edge (6) is provided on the downward extension of the inner annular side wall (3). .

(7) is an annular working chamber defined by these outer and inner annular cutting holes (5), (6), the working chamber ceiling (4), and the internal ground G1 below, and (8) is a working chamber. Ceiling (4)
(9) is an appropriate number of shafts extending from the opening (4) to the ground side, and (10) is an aerolock provided above.

In addition, the outer wall surface of the outer annular cutting edge (5) is the outer annular side! ! (
2) has a step (5a) that protrudes slightly outward from the outer wall surface, and when the annular pressure caisson body (1) is sunk, an outer gap (11) is formed between it and the outer ground G. , a well-known lubricant such as bentonite solution is injected.

The inner wall surface of the inner annular cutting edge (6) also has a step (6a), which similarly protrudes from the inner wall surface of the inner annular side wall (3), and there is an inner gap (11') between it and the inner circumferential disc G. is formed. Similarly, the lubricant is filled, and in this case, in the present invention, the height H from the step (5a) of the outer annular cutting edge (2) to the lower end of the outer annular cutting edge (5)
is from the stepped part (6a) of the inner annular cutting edge (6) to the inner annular cutting edge (3).
) is lower by a than the height h to the lower end of the frame. In other words, the length of the outer annular cutting edge (2) extends downward by an amount a longer than that of the inner annular cutting edge (3). The optimum dimension of a is selected as appropriate depending on the scale of the annular pressure caisson (earth).

In addition, W is groundwater, and Wo is groundwater in the work room.

Therefore, when sinking the annular pressurized air caisson body (1), air is supplied to the annular working chamber (7) via a compressor and air pipes (not shown) installed on the ground, and the internal air pressure is applied to the inner annular blade. The pressure is maintained at a pressure equal to the water head pressure to the lower end of the mouth (6), and the internal ground G1 is excavated by human or mechanical force in the annular work chamber (7), and the excavated soil is
For example, it is loaded into a caisson packet (not shown) and passes through the opening (8) and shaft (9) to the aerodynamics (10).
It is discharged to the ground side where it is under more atmospheric pressure.

In these processes, if the high pressure air in the annular working chamber (7) becomes overpressure or the annular pressure air caisson body (soil) is tilted, the lower end of the inner annular cutting opening (3), which is shorter by the dimension a, High pressure air leaks to the outside as shown by arrow P from
The high pressure air rises along the inner wall of the inner annular side chamber (3) and leaks to the internal ground G, and since the lower end of the outer annular cutting opening (2) is always below the groundwater level, high pressure air flows from here to the outer circumference. Ground G
The annular pressure caisson (1) can be safely sunk without leaking into the tank.

(Embodiment 2) Figures 2(a) to (C) show a second embodiment of the present invention. In this embodiment, the height of the inner annular cutting edge (6-1) is The height is the same as (5), and the inner annular cutting edge (
6-1) A plurality of notch-shaped recesses (
6-2) at appropriate intervals, and this recess (6-2)
It is characterized in that when excess air in the annular working chamber (7) or when the annular pressure air caisson body (upper) is tilted, high pressure air P leaks to the internal ground 01 side through the annular work chamber (7).

Other configurations and functions are the same as those of the previous embodiment, so
In order to avoid duplication of description, the same members are designated by the same reference numerals and their description will be omitted.

(Effects of the Invention) According to the present invention configured as described above, the high pressure air in the annular working chamber leaks to the inner ground side, so that high pressure air does not leak from the outer annular cutting edge side, and therefore the outer circumference It is possible to prevent surrounding ground collapse and ground subsidence without damaging the ground G.

Additionally, since there is no leakage of high-pressure air into the surrounding ground, oxygen-deficient air is not sent to surrounding tunnels or basements, improving safety.

[Brief explanation of drawings]

FIG. 1(a) is a vertical cross-sectional view of the first embodiment of the present invention, and FIG. 1(b) is a vertical cross-sectional view of the first embodiment of the present invention.
The figure is a sectional view taken along the line A-A of the same as above, and FIG.
A vertical cross-sectional view of the embodiment, FIG. 3B is a bottom view taken along line B--B in the same manner as above, FIG. 3C is a partial perspective view, and FIG. 3 shows a conventional example. Figure 1 (a) l ・ ・ ・ ・ 2 ・ ・ ・ ・ 3 ・ ・ ・ 4 ・ ・ ・ ・ 5 ・ ・ ・ ・ 5a, 6a 6.6-1 7 ・ ・ ・ ・ ・ Annular pressure caisson body outer annular Side wall inner annular side wall pressurized air work chamber Ceiling outer annular cutter mouth step inner annular cutter mouth annular work chamber

Claims (2)

[Claims] (1) In an annular pressure caisson having an outer annular side wall, an inner annular side wall, and an annular pressure work chamber, the length of the outer annular cutting hole provided at the lower part of the outer annular side wall is the inner annular cutting hole of the inner annular side wall. An annular pressure caisson characterized by extending downward longer than the length of the annular pressure caisson. (2) In an annular pressure caisson having an outer annular side wall, an inner annular side wall, and an annular pressure work chamber, the lengths of the cutting holes on the outer and inner annular side walls are approximately the same, and An annular pressure caisson characterized by having a recessed part.