JPS5813828A - Sucker for soil and sand in pneumatic caisson work - Google Patents

Abstract

PURPOSE:To perform mucking work without resorting to buckets by using a system in which soil and sand are discharged to the outside of a caisson by a telescope-type suction pile which is approached to or separated from the shallow sump by a hung wire rope. CONSTITUTION:The ground inside a caisson A is excavated by sucking up soil and sand with water by a suction pipe by jetting high-pressure water from the nozzle 2 of a jet pump 1, and the excavated soil and sand are discharged through a discharge line 13 to a sand sedimentation basin. In case where the distance H becomes less due to the settlement of the caisson A as the excavation exceeds, a telescope 3b is provided to the suction pipe 3, a hung wire rope 29 is connected to the jet nozzle 19 to hang down the suction pipe, the hung wire rope is sent out when the distance H becomes less, and the suction port 3a is adjusted by the telescope in such a way as to position it in an adequate place inside the shallow sump B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earth and sand suction device in a pneumatic caisson construction method.

Conventionally, in the pneumatic caisson construction method, packets were often used to transport waste out of the caisson.

However, when using the packet lifting method, the material lock that shields the inside of the caisson from the atmosphere must be opened and closed each time a packet passes, consuming a large amount of air and increasing the number of material locks. Depending on the depth of excavation, a large number of compressors must be installed. If you want to increase the capacity to carry out loose waste, the frequency of opening and closing of the material lock will increase, which will require an increase in the number of compressors installed. Further, the packet lifting method cannot carry out continuous removal of waste due to its mechanism, and cannot necessarily be said to be an efficient method of removing waste.

Therefore, the present inventors hereby propose an earth and sand suction device using a jet pump. That is, a jet pump is installed inside the caisson, and by jetting high-pressure water supplied from a pump drive water supply line from a nozzle, earth and sand are sucked in together with water through a suction pipe, and are discharged outside the caisson through an earth and sand discharge line. According to such a device, there is no need to open and close the material lock to carry out waste, and therefore air consumption can be reduced and waste can be carried out continuously, eliminating the above-mentioned drawbacks of packet lifting. can.

Problems with such earth and sand suction devices are that the suction port of the suction pipe must be adjusted to an appropriate position within the boiler as the caisson sinks, and that in-plane devices such as the sag joist may be damaged due to the sinking of the caisson. Appropriate measures must be taken to prevent damage.

Therefore, one object of the present invention is to enable the suction port of the suction pipe to be easily adjusted to an appropriate position within the kettle as the caisson sinks; The objective is to prevent damage to in-plane devices such as suction parts due to subsidence.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 1 shows the earth and sand suction system in the pneumatic caisson construction method, and the inside of the caisson A is maintained at high pressure in the conventional manner. A jet pump, generally indicated by 1, is installed inside the caisson A, and sucks up water and earth and sand from the caisson B in a manner that will be described in detail later. A conventionally known jet pump 1 can be used as the jet pump 1, and as shown in FIG. 2, it is equipped with a nozzle 2 for jetting high-pressure water and a suction pipe 3. 3, the ground is excavated by sucking up the earth and sand along with the water. At this time, air may be sucked in through the air inlet 1a and air may be ejected together with water.

A driving water supply line 4 for supplying driving water to the jet pump 1 is provided. A feed pump 5 is installed in the sand settling basin C, and the feed pump 5 pumps water into the feed tank 6. Then, the driving water is supplied from the feed tank 6 to the jet pump 1 via the driving water supply line 4 by the driving water pump 7. . A water level gauge 8 is installed in the feed tank 6, and a check valve 9 is installed at the discharge port of the driving water pump 7.
, a gate valve 10, and a check valve 11 and a gate valve 12 at the inlet of the jet pump 1. Further, the earth and sand sucked up by the jet pump 1 is discharged to the settling basin C through the earth and sand discharge line 13. The earth and sand discharge line 13 is provided with an automatic valve 14.17, a manual valve 15.16 and a flow meter 18. Furthermore, a water jet is ejected from a circular jet nozzle 19 to perform jet excavation at the kettle B, and a make-up water line 20 is provided to replenish water to the kettle B. A pump 21 supplies high pressure water.

Make-up water line 20 has check valves 22.24.26
, manual valves 23.25.27 are provided. The automatic pulp 14 installed in the earth and sand discharge line 13 detects that when the water level of the pot lift B falls and the suction pipe 3 starts to suck air, the compressor 28 is activated, and the air pressure from the compressor 28 closes the automatic pulp 14 to shut off the air. It is designed to prevent escape.

According to this waste removal system, the drive water supply line 4
The high-pressure water supplied through the pump 1 and the air flowing in from the air inlet 1a together with the high-pressure water are ejected from the nozzle 2 of the jet pump 1, and the sediment is sucked up by the suction pipe 3 and sent through the sediment discharge line 13 to the settling basin. Discharge to C.

By the way, when H changes (decreases) in FIG. 3 due to the progress of excavation and the sinking of caisson 8 by the above-mentioned system, the suction port 3a of the suction pipe 3
It is necessary to adjust it to the appropriate position of the pot lift B. Therefore, in the present invention, the suction pipe 3 is provided with a telescopic portion 3b, and a hanging wire loaf 29 for adjustment is provided on the circular jet nozzle 19 fixedly installed on the suction pipe 3.
．． 29 and suspend the suction pipe 3. If caisson A sinks and H becomes smaller, hanging wire row 129.
29, and adjust the suction port 3a of the suction pipe 3 to an appropriate position in the boiler B using the telescopic portion 3b.

In addition, in order to prevent damage to in-plane devices such as the suction part due to the sinking of the caisson A, the present invention is designed in Figs.
As shown in b), the jet pump 1 is connected to the swivel device 3.
It is connected to the driving water supply line 4 and the earth and sand discharge line 13 via a 0.30 mm cable.

Therefore, when the caisson A sinks, by pulling the hanging wire rope 29.29, the suction pipe 3 can be pulled upward by rotating with the swivel device @30.30 as shown in Fig. 4 (b). Can be done.

This can prevent damage to the suction section.

As explained above, according to the present invention, waste can be carried out without using packets in the pneumatic caisson construction method, and the drawbacks caused by packet transport can be solved. The suction port of the pipe can be easily adjusted to all appropriate positions within the boiler, and damage to in-plane devices such as the suction section due to sinking of the caisson can be reliably prevented.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a waste removal system in the pneumatic caisson construction method in which the present invention is implemented. FIG. 2 is a side sectional view showing a part of the jet pump in plan view. FIG. 3 is a front view showing a telescopic suction pipe. Figures 4 (a) and (b) show the state in which the jet pump is connected to the driving water supply line and the sediment discharge line by a swivel device, (a) is a front view, and (b) is the X of (a). It is a line arrow view. A... Caisson B... Kamaage C
...Sand basin 1 ... Jet pump 2 ... Nozzle 3 ... Suction pipe 4 ... Drive water supply line 5 ...
... Feed pump 7 ... Drive water pump 13 ... Sediment discharge line 14 ...
... Automatic valve 19 ... Circular jet nozzle 20 ... Makeup water line 21 ...
...Makeup water pump 28...Compressor
29... Hanging wire robe 30...
・Swivel device patent applicant Kajima Corporation

Claims (2)

[Claims] (1) In the sediment suction device that is installed inside the caisson and sucks in sediment, the upper sand suction device is equipped with a jet pump, and the jet pump squirts high-pressure water supplied from outside the caisson from a nozzle to collect sediment through a suction pipe. The suction pipe is of telescopic type and is suspended by a hanging wire rope, so that it can be moved close to and away from the kettle. This is a soil suction device for the pneumatic caisson construction method. (2) In the sediment suction device that is installed inside the caisson and sucks in sediment, the upper sand suction device is equipped with a jet pump, and the jet pump squirts high-pressure water supplied from outside the caisson from a nozzle to collect sediment through a suction pipe. The suction pipe is of a telescopic type and is suspended by a hanging wire rope so that it can be moved close to and away from the kettle. Ori. Furthermore, the jet pump is connected to the pump drive water supply line and the earth and sand discharge line by a swivel device, and the swivel device rotates so that the suction pipe can be pulled upward by the hanging wire rope. A feature of the earth and sand suction device in the pneumatic caisson construction method.