JPS605093Y2 - Pressure caisson for spring water strata - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pneumatic caisson, and its purpose is to provide a pneumatic caisson that can be sunk into a spring water stratum with high efficiency.

Figure 1 shows an embodiment of the pneumatic caisson of the present invention.
In this figure, reference numeral 1 denotes a caisson body made of concrete, and this caisson body consists of a working chamber 2, an air volume chamber 3, and an atmospheric chamber 4.

6 is a shaft attached to the upper slab 5 of the air volume chamber 3;
8 is a hatch for opening and closing the upper and lower end openings of this shaft; 9 is a lock attached to the upper slab 10 of the working chamber 2; 11 is a hatch for opening and closing the upper end opening of this lock;
2 is a reverse circulation drill, and this reverse circulation drill includes a turntable 13 placed on the top surface of the lock 9, an oil motor 14 that rotates the turntable, and a kelly bar 15 that passes through the center of the turntable 13. A drill pipe 16 connected to the lower end of the kely bar and inserted into the working chamber 2 and a suction pipe 17 passing through the upper slab 5 of the air volume chamber 3
and a suction hose 19 which connects this suction pipe to the Kelly lever 15 via a swivel joint 18.

20 is a water supply pipe that penetrates the upper surface slab 5 of the air volume chamber 3;
21 is a water supply hose connected to the lower end of this water supply pipe and suspended into the working chamber 2.

In order to sink the inventive pneumatic caisson into the spring water stratum, first, the reverse circulation drill 12 is removed from the caisson body 1 and the caisson is placed in the state shown in FIG. The open caisson construction method will be used to sink into the Yuki stratum G.

When this caisson has sunk to a relatively shallow depth in the spring stratum G in this way, the reverse circulation drill 12 is installed in the caisson as before and the first
In the state shown in the figure, pressurized air is sent into the rear shaft 6, air volume chamber 3, and working chamber 2, and groundwater W leaking into the working chamber 2 due to the air pressure infiltrates into the air volume chamber 3 and shaft 6. While preventing this, the drill pipe 16 is rotated by the oil motor 14 via the rotary table 13, and the ground at the bottom of the work chamber 2 is excavated by the pit 16' at the lower end of the drill pipe 16, and the excavated earth and sand are drained into the groundwater W.
At the same time, the drill pipe 16, kely bar 15, swivel joint 18, suction hose 19, suction pipe 17, etc. are discharged to the outside.

In this way, the caisson will cause the spring water formation G due to its own weight.
The inside of the caisson gradually sinks, so as the sinking progresses, a concrete tube (not shown) is added to the top of the caisson, and a suction pipe 17 is also added, allowing the caisson and concrete tube to sink to the required depth by their own weight. It is something.

If the amount of underground water becomes low during this construction, the same construction as above is carried out while replenishing water from the outside into the work room 2 from the water supply pipe 20 and the water supply hose 21.

The caisson of this invention is made to sink into the spring water stratum, and as mentioned above, it is constructed using a complicated construction method such as the pressure air caisson construction method or the open caisson construction method to sink to a relatively shallow depth in this stratum. However, the subsequent subsidence to a deep depth is carried out using a construction method that does not require complicated labor, such as the reverse circulation drilling method, so the entire process of subsidence into the spring water stratum is not required like a conventional caisson. Compared to methods that require complicated labor, such as the pressurized caisson construction method or the open caisson construction method, construction is significantly simplified, the construction period can be shortened, and construction efficiency can be significantly improved. It is possible.

In addition, it has already been proposed that a packet-type lift conveyor is installed inside the pneumatic caisson to discharge the excavated soil to the outside, as in the caisson described in the Japanese Patent Publication No. 36-57. Since the excavated soil is scooped up in a packet and discharged to the outside, the efficiency of discharging the excavated soil is extremely low.

However, since the device of the present invention uses a reverse circulation drill to suck up excavated soil together with groundwater or supplementary water from outside and discharge it to the outside, it has a much higher discharge efficiency of excavated soil than the one described in the above publication. It is.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the pneumatic caisson of the present invention, and FIG. 2 is a drawing showing the state in which the reverse circulation drill provided inside the pneumatic caisson is removed. 2...Working room, 16...Drill pipe, 13°14.15...Device i for rotating the drill pipe, 17.19...Suction pipe , 12... Reverse circulation drill, 1... Caisson body.

Claims (1)

[Scope of utility model registration request] The interior is an atmospheric chamber through a slab and a hatch that can be opened and closed.
A drill having a water supply means extending from the atmospheric chamber to the working chamber and capable of supplying water into the working chamber in a caisson body which is sequentially divided into an air volume chamber, a working chamber, etc., and having a bit at the tip provided in the working chamber. a pipe, and a device provided in the air volume chamber for rotating the drill pipe;
A pressurized air caisson for spring water strata, characterized in that a reverse circulation drill consisting of a suction pipe connected to the upper end of the drill pipe is detachably attached to the caisson body.