JPS6183720A - Method and device of pulling off steel pipe pile - Google Patents

Abstract

PURPOSE:To increase a pull-off force and to enable a steel pipe pile at any place to be easily pulled off, by a method wherein a lid is attached to the top part of a driven steel pipe pile to form a liquidtight chamber, and high pressure liquid is fed to the liquidtight chamber for pressurization to pull off the steel pipe pile. CONSTITUTION:A steel pipe pile 2 is driven in a ground 1, a lid 3 is attached to a top part, and the lid 3 and a high pressure generator 4 are interconnected through a high pressure feed pipe 5. By opening a high pressure valve 8 through driving of a high pressure pump 7, high pressure liquid flows in a liquidtight chamber 15 through a high pressure feed pipe 5. By filling the liquidtight chamber 15 with a high pressure, an upward static liquid pressure is exerted on the lid 3 to push up the lid. When a pressurizing force is increased over a friction force between the surface of a steel pipe pile 2 and a ground 1, the steel pipe pile 2 is pulled off upward. This enables the steel pipe pile to be recovered at a very low cost and reused.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and device for extracting steel pipe piles, and in particular, to a method for extracting steel pipe piles and an apparatus therefor. The purpose is to extract the steel pipe piles under pressure and recover and reuse them.

[Conventional technology]

Recently, many steel pipe piles have been used in coastal civil engineering, large-scale river construction, etc. for the purpose of water stopping or as retaining walls for seawalls.

Since these steel pipe piles are originally temporary structures and are expensive, it is desirable to pull out the used steel pipe piles, collect them, and reuse them when construction is completed. However, during driving construction, a strong frictional force acts between the surface of the steel pipe pile and the ground, and a great force is required to pull out the steel pipe pile.

Therefore, if we were to create a pile extraction machine with a large pulling force that can directly pull out steel pipe piles against the frictional force, it would be very large and expensive, and depending on the construction site, the pile Conventionally, steel pipe piles were left in place without being pulled out because there was no way to receive the reaction force from the pulling force of the pulling machine.

[Problem that the invention seeks to solve]

This invention solves the problem of the difficulty in pulling out steel pipe piles as described above.

Therefore, an object of the present invention is to provide a means that has a strong pulling force and can easily pull out steel pipe piles at any location. A further object of the present invention is to provide a steel pipe pile extraction device that has a simple structure and is inexpensive.

[Means for solving problems]

The method for extracting a steel pipe pile, which is the specific invention of this application, involves attaching a lid to the top of the driven steel pipe pile to form a liquid-tight chamber, and supplying high-pressure liquid to this liquid-tight chamber to pressurize it.
The steel pipe pile extractor used to carry out this specific invention extracts steel pipe piles, and connects a lid attached to the top of a driven steel pipe pile and a high-pressure liquid generator through a high-pressure liquid supply pipe. Connected.

[Effect]

When high-pressure liquid is supplied to the liquid-tight chamber formed in the steel pipe pile, the liquid pressure inside the liquid-tight chamber increases, and upward pressure is applied to the lid at the top of the steel pipe pile. When this pressure becomes greater than the frictional force between the surface of the steel pipe pile and the ground, the steel pipe pile gradually moves upward. Generally, the initial friction between the surface of the steel pipe pile and the ground is large, and as the modulating pipe pile moves, the frictional force decreases rapidly. If it is replenished, extraction can be continued at a relatively low pressure. As the extraction progresses,
The frictional force decreases so that it can be lifted and recovered using a crane or the like.

〔Example〕

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

FIG. 1 is an explanatory diagram showing the configuration of a steel pipe pile extraction device used in an embodiment of the present invention, in which a lid 3 is attached to the top of a steel pipe pile 2 driven into the ground 1. , this lid 3 and a high pressure liquid generator 4 are connected via a high pressure liquid supply pipe 5.

In this embodiment, the high-pressure liquid supply device 4 includes a high-pressure pump 7 driven by an electric motor 6, a high-pressure valve 8, a safety valve 9, and a pressure gauge 10. The electric motor 6 drives the high-pressure pump 7 to generate high-pressure liquid. Then, by opening the high pressure valve 8, the high pressure liquid is delivered to the high pressure liquid supply pipe 5.

The lid 3 has a connecting fitting 12 for connecting an exhaust valve 11 and a high-pressure liquid supply pipe 5 on the upper part, and hangers 13 on both sides, and a joint part 14 is fixed to the steel pipe pile 2 by welding. A liquid-tight chamber 15 is formed at the top of the steel pipe pile 2. Note that the joint portion 14 may be attached using any other method that provides the necessary strength and liquid tightness.

As the high pressure liquid supply pipe 5, it is desirable to use a flexible pipe such as a high pressure hose in order to follow the removal of the steel pipe pile.

Now, the high-pressure pump 7 is driven and the high-pressure valve 8 is opened (and high-pressure liquid enters the liquid-tight chamber 15 from the high-pressure supply pipe 5).

Initially, until the liquid-tight chamber 15 is filled with high-pressure liquid, the exhaust valve 1
1 is opened to discharge the internal air to the atmosphere, and when the liquid-tight chamber is completely filled with high-pressure liquid and there is no excess air, the exhaust valve 11 is closed.

When the liquid-tight chamber 15 is filled with high-pressure liquid, upward static pressure is applied to M3 and it is pushed upward.

The high-pressure liquid is continuously supplied from the high-pressure pump 7, so when the pressure applied by the high-pressure liquid increases beyond the frictional force between the surface of the steel pipe pile 2 and the ground 1, the steel pipe pile 2 moves upward. .

Here, since air is removed from the liquid-tight chamber, even if the steel pipe pile 2 starts to pull out and the initial friction decreases rapidly, there is no fear that the steel pipe pile 2 will suddenly come out and fly out.

Once the material has been released to a certain extent and the frictional force becomes sufficiently small, it can be lifted up with a crane or the like and recovered efficiently.

Depending on the condition of the ground 1, the liquid-tight chamber 1 may be leaked from the inner wall of the steel pipe pile 2.
The high-pressure liquid in the high-pressure pump 5 may dissipate into the ground, but in this case, the pointer of the pressure gauge 10 is monitored and the high-pressure valve 8 is controlled to increase the discharge amount from the high-pressure pump 7. In addition, if the ground 1 is very soft, the ground in the liquid-tight chamber 15 may sink, or the high-pressure liquid may seep into the ground rapidly, making it difficult to maintain the pressure in the liquid-tight chamber 15. There is. At this time, as shown in FIG.
In order to protect the base 6, a rubber sheet 17 or the like is laid down, or bentonite or the like is mixed into the bottom to reduce the water permeability of the ground and prevent a pressure drop. Pressure water is usually used as the high-pressure liquid, but it is convenient to use bentonite liquid in ground with high permeability.

When the footing of the ground 1 where the steel pipe pile 2 is driven is poor,
It is also possible to make the high-pressure liquid supply pipe 5 long and perform remote control, and it is also possible to connect the underwater steel pipe pile 2 to the high-pressure water generator 4 installed on board the ship with a long high-pressure water supply pipe 5 and extract it. .

〔Effect of the invention〕

As described above, according to the present invention, a steel pipe pile can be easily extracted from any location using a simple device, and the steel pipe pile recovery work can be carried out safely and efficiently. Therefore, the steel pipe piles can be recovered and reused at a very low cost, making it extremely economical.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of a steel pipe pile extraction device used in an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a method for protecting the bottom of a liquid-tight chamber. In the figure, 1 is the ground, 2 is a steel pipe pile, 3 is a lid, 4 is a high aqua regia generator, 5 is a high-pressure liquid supply pipe, and 15 is a liquid-tight chamber. Patent applicant: Yutaka Oyamauchi, Furukawa Mining Co., Ltd.

Claims (2)

[Claims] (1) A method of attaching a lid to the top of a driven steel pipe pile to form a liquid-tight chamber, and extracting the steel pipe pile by supplying high-pressure liquid to the liquid-tight chamber and pressurizing it. (2) A steel pipe pile extraction device in which a lid attached to the top of a driven steel pipe pile to form a liquid-tight chamber and a high-pressure liquid generator are connected via a high-pressure liquid supply pipe.