JPH0258632A - Pneumatic caisson construction and device therefor - Google Patents

Abstract

PURPOSE:To increase the excavation depth by connecting a pressurization holding room to the airtight room of a caisson and connecting said holding room to a living room under a reduced pressure on the ground and controlling the inside of the living room so that the saturated submersible state is generated and released. CONSTITUTION:When a foundation is excavated by the pressing to a pressure of 7kg/cm<2> which corresponds to the pressure at the caisson excavation depth of 70m under water, an operator is housed into a living room 10 under a reduced pressure. Then, the helium/oxygen mixed gad is supplied into the living room 10 and pressurized to 7kg/cm<2> by a saturated submersible system controller 12. At the same time, the temperature, humidity, and carbon dioxide gas in the living room 10 are adjusted by the operation of an environment control unit 11, and the living for 24 hours is permitted Then, the operator is transferred to the pressurization holding room 7 connected to the living room 10, and the room 7 is closed, and conveyed onto an airtight room 6 by a crane 13, and connected, and the operator is sent into a working room 2, passing through a vertical pipe 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a new technology for constructing foundations for buildings, bridges, etc. by sinking caissons while suppressing groundwater flow using air pressure when excavating deep into the ground. This article relates to the matic caisson construction method and its equipment.

[Conventional technology]

Conventionally, in the pneumatic caisson construction method, as shown in Fig. 2, a working chamber 21 was installed at the bottom of the caisson 20, and an air pipe 2 was installed.
Work is carried out under high pressure by blowing compressed air from 2, and a double air lock 24 is provided at the upper end of the standpipe 23 for workers to enter and exit, so that they gradually acclimatize from high pressure to atmospheric pressure to prevent latent diseases. There was a method to do this.

[Problem to be solved by the invention]

In the conventional pneumatic caisson construction method, work is carried out under high pressure using compressed air, so if the depth exceeds 30 m, nitrogen narcosis occurs and the work becomes impossible, resulting in the problem that construction of caisson deeper than 30 m cannot be carried out. was there. In addition, since the work is carried out under high pressure, the number of workers is 3
Changes must be made within 0 minutes to 1 hour, and in this case, suddenly going from a high-pressure area to atmospheric pressure can cause dizziness, headaches, and in severe cases, rupture of blood vessels. Therefore, it is necessary for the body to get used to the intermediate pressure little by little, and it takes about 4 hours to return to atmospheric pressure.
This method takes time and requires the preparation of a large number of substitute personnel, which has the problem of extremely poor work efficiency. The object of this invention is to make it possible to increase the depth of excavation of a foundation and to improve work efficiency.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention removably connects a pressurization holding chamber 7 for maintaining a saturation diving state to an airtight chamber 6 provided at the upper end of the standpipe 5 of the caisson 1. A pneumatic caisson construction method in which the holding chamber 7 is removably connected to a pressurized living room 10 provided on the ground, and the inside of this pressurized living room 10 is controlled to generate and release a saturation diving state, and the caisson 1 is built A pressurization holding chamber 7 detachably attached to the airtight chamber 6 at the upper end of the tube, a pressurization/depressurization living chamber 10 detachably attached to this pressurization holding chamber 7, and a saturation chamber for controlling this pressurization/depressurization living chamber 10. A pneumatic caisson device comprising a diving system control device 12 is provided.

[For production]

The operation of this invention will be explained with reference to Examples.

When excavating deep foundations by pressurizing the excavation depth of the caisson to 7 kg/ct, which is the pressure equivalent to 70 m underwater, the workers are housed in the pressurized living room 10 and the saturation diving system control device 12 (saturation diving For details, please refer to "Overview of Saturation Diving Work" published by Marine Science and Technology Center), supplying helium and oxygen mixed gas to the pressurized living room IO.
At the same time, the environment control unit 11 is activated to adjust the temperature, humidity, and carbon dioxide gas in the pressurized and depressurized living room 10, and the workers are allowed to live there for 24 hours to give them a saturation diving condition. Pressurized and depressurized living room 10
The pressurized holding chamber 7 is moved to the pressurized holding chamber 7 connected to the airtight chamber 7 and sealed, and the pressurized holding chamber 7 is carried onto the airtight chamber 6 by a lifting crane 13, joined together, and sent into the working chamber 2 through the standpipe 5.

Inside the work room 2, a high-pressure compressed gas of 1 kg/cA containing a mixture of helium and oxygen is sent through the air pipe 3, making it possible to suppress water pressure below 70 m below the surface of the water, allowing workers to perform saturation diving. Since it is pressurized, the amount of inert gas such as helium or nitrogen dissolved in the body is constant, and it can be used continuously for a week or a month.

In this case, high pressure compressed gas is 5kg/cJIl~20k
If the ratio is g/c, it is possible to create a condition that can withstand the pressure equivalent to being 50 to 200 meters below the water surface.

To replace workers, they are sent to the pressurized and depressurized living room 10 in the reverse order of entering the work room 2, where they are gradually returned to atmospheric pressure over 24 hours. The decompression time is the same regardless of the length of residence time.

In addition, in the case of short-time work, the work can be performed by simply connecting the pressurization holding chamber 7 to the airtight chamber 6 without using the pressurization/depressurization living room 10.

〔Example〕

Embodiments of the invention will be described with reference to the drawings.

A compressed gas containing a mixture of helium and oxygen is sent from an air pipe 3 to a working chamber 2 located at the lowest part of the caisson 1 at a high pressure (for example, 7 kg/cm), thereby removing the ground water from the cutting hole 4. is suppressed.

An airtight chamber 6 is provided at the upper end of the standpipe 5, and a pressure holding chamber 7 is detachably connected to the upper part of the airtight chamber 6. The pressurized holding chamber 7 is kept under constant pressure for a long time (24 to 48 hours) until the inert gas in the breathing gas saturates the human tissue and no further absorption or excretion occurs, that is, saturation. It is designed to maintain a submerged state, and the worker enters the work chamber 2 from the pressure holding chamber 7 through the airtight chamber 6 and the standpipe 5 and excavates the bottom surface 8. 9 is an inlet/outlet pipe for excavated soil, working tools, etc., and the upper end is airlocked.

A pressurized living room 10 and an environment control unit 11 are installed on the ground. The pressurized living room 10 is equipped with equipment necessary for daily life, and above this room 10 is a pressurized living room 10 and an environmental control unit A saturation diving system control device 12 is provided to control the unit 11, and the saturation diving system control device 12 controls the pressurization and depressurization of the mixed gas of helium and oxygen in the pressurized living room 10, and the temperature of the environment control unit 11. It is designed to adjust humidity and carbon dioxide gas. 13. When transporting workers into and out of the caisson 1 using the lifting crane of the pressurization holding chamber 7, the pressurization holding chamber 7 is connected to the pressurized living room 10 as shown by the chain line to put the workers in a saturation diving state. After that, the pressurization holding chamber 7 is connected to the airtight chamber 6 as shown by the solid line, or the pressurization holding chamber 7 into which the worker was transferred from the airtight room 6 is connected to the pressurized and depressurized living room 10 as shown by the chain line. used to return to atmospheric pressure.

〔Effect of the invention〕

This invention overcomes the conventional caisson excavation depth limit of 3.
0m can be dramatically improved from 50m to 200m, and instead of requiring 24 hours to pressurize to enter the workroom, it is possible to continue working in the workroom for more than a month, reducing the length of stay. Regardless, the time needed to reduce the pressure to atmospheric pressure is the same, so work efficiency is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a cutaway front view showing one embodiment of the present invention, and FIG.
The figure is a cutaway front view showing a conventional example. 1...Caisson, 5...Stand pipe, 6...Airtight room, 7
... Pressure holding chamber, 10... Pressurization and depressurization living room, 12...
・Saturation diving system control device

Claims (1)

[Claims] 1. A pressurized holding chamber (7) for maintaining a saturation diving state in an airtight chamber (6) provided at the upper end of the standpipe (5) of the caisson (1).
), and this pressurization holding chamber (7) is detachably connected to a pressurized and depressurized living chamber (10) provided on the ground, and the inside of this pressurized and depressurized living chamber (10) is used to create a saturation diving state. and pneumatic caisson construction method that controls release. 2. The airtight chamber (6) at the upper end of the standpipe (5) of the caisson (1)
) and a pressurized/depressurized living chamber (10) removably attached to this pressurized/maintained chamber (7).
) and a saturation diving system control device (12) that controls this pressurized/depressurized living chamber (10).