JP3198598B2 - How to pull out steel members buried underground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for pulling out a steel member such as a steel pipe pile, a mold steel or a steel sheet pile buried underground in the longitudinal direction.

[0002]

2. Description of the Related Art In redevelopment of an urban area, it is common to break down an existing building and construct a new building. However, with this kind of construction, unnecessary work buried in the ground is required. It may be necessary to pull out steel pipe piles and remove them. Steel pipe piles that have been buried for a long time have a very strong bonding force with the surrounding ground, and are often not easily pulled out.
Generally, existing piles are pulled out using heavy equipment such as pullers and cranes.However, there are many piles that cannot be pulled out simply by simply pulling them. You also need.

[0003] Conventionally, the ground around the pile is excavated as a pretreatment, the connection between the pile and the ground is cut or weakened, and the pile is then pulled out so that the existing pile can be pulled out as smoothly as possible. I often take steps. In order to excavate the ground around the existing pile,
For example, Japanese Patent Publication No. 56-31415 and Japanese Utility Model Laid-Open No. 63-4
An apparatus as disclosed in Japanese Patent No. 5849 has been developed. Each of these devices is attached to a large-scale device such as a crawler crane, and is configured to excavate the ground around the pile while descending along the existing pile.

[0004]

As described above, if the ground around the pile is excavated and then pulled out, the pile can be pulled out with a relatively small force without making the surrounding ground so rough. However, there was a problem that the pre-processing work of excavating around the pile was very troublesome. It is necessary to prepare and set up a large-scale support device such as a crane, and the work of attaching and removing the excavator to and from the existing pile is troublesome and time-consuming.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to reduce the friction between the steel member and the ground by pulling out the ground while weakening the connection between the steel member and the ground, while having a configuration that can be easily implemented. It is an object of the present invention to provide a method capable of reducing a force and pulling out a steel member such as a steel pipe pile buried underground with a small force.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for extracting a plurality of steel members buried underground, wherein any one of the steel members is first connected to a negative electrode as an object to be extracted, and the steel member is connected to the negative electrode. after applying a DC voltage to other steel members are embedded by connecting the positive electrode in the vicinity of, a DC voltage is applied by connecting the steel member in the positive electrode as well as connected to the negative electrode as a target pull the other steel member Then, electrolysis is caused by the electrolyte solution contained in the ground to generate hydrogen gas around the steel member, thereby reducing the frictional force of the ground against pulling out the steel member. The member was pulled out in its longitudinal direction.

[0007]

The ground under normal conditions contains a considerable amount of water and contains a large amount of electrolyte. Therefore, when two electrodes are inserted into the ground and a DC voltage is applied, an electrolysis reaction occurs between the electrodes via the underground electrolyte solution, and hydrogen gas is generated on the negative electrode side. The same phenomenon is negative
Occurs between the steel member to be the pole and the other steel member to be the positive electrode ,
Hydrogen gas is generated from the surface of the steel member to be extracted . I expansion More of the gas volume at the time of the gas generator,
The surface of the steel member and the ground are separated, and the bonding force is significantly reduced. The Ri underground water by electroosmotic phenomenon collector or the negative Gokuhagane member <br/> side, also caused soil is softened effect around the steel member is a pull-out target. As a result, the frictional force (ground frictional force) between the steel member and the ground when the steel member is pulled out is extremely small. Thereafter, if the steel member is pulled out, the force required for pulling out is small.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention is preferably applied to a work of pulling out a pile such as a round steel pipe, a square steel pipe, and an H-shaped steel, the present invention is also applicable to a work of drawing a plate-like member such as a steel sheet pile. I can . In one general field, since a plurality of steel pipe piles are embedded at appropriate intervals, it shall be the cathode another steel pipe pile closest to it during withdrawal of the some steel pipe pile. Such an embodiment is shown in FIG.

As shown in FIG. 1, two steel pipe piles 2 and 3 are buried in a ground 1. A DC power supply 4 is prepared, one steel pipe pile 2 is connected to the negative electrode of the power supply 4 (this pile 2 is the object to be drawn first), the other steel pipe pile 3 is connected to the positive electrode of the power supply 4, and the ground between the two poles is connected. DC current to Appropriate values of the DC voltage, current, or energization time applied at that time are determined by the distance between the piles 2 and 3, the length and diameter of the pile, the moisture content of the ground, and the electrolyte content, and the like.

When a direct current is passed between the steel pipe piles 2 and 3, hydrogen gas is generated from the surface of the negative steel pipe pile 2 and the bonding force between the steel pipe pile 2 and the ground 1 due to its gas expansion action. Is significantly reduced. When the steel pipe pile 2 is pulled out using a crane or the like in this state, the force required for pulling out is small, and the roughness of the surrounding ground due to pulling out is reduced.
In addition, since the water in the ground collects on the steel pipe pile 2 side of the negative electrode due to the electroosmosis phenomenon due to energization, the ground around the pile 2 is softened, and the above effect is further enhanced.

[0011]

As described in detail above, according to the present invention, there is no need to insert another electrode into the ground,
Extraction target among multiple steel members buried underground
Vicinity of one of the steel member as a negative electrode, the steel member is
Other steel members are embedded in a very simple pretreatment task of passing a direct current as a positive electrode, weaken the bond between the soil and the steel member, to greatly reduce the frictional force of the ground for the withdrawal of the steel member be able to. With such a configuration that can be easily implemented, the work of pulling out the steel member can be easily performed with relatively small force, and the surrounding ground does not need to be so roughened at the time of pulling out.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a state of a pre-pulling-out operation of a steel pipe pile according to an embodiment of the present invention.

[Explanation of symbols]

 1 Ground 2 Steel pipe pile (to be pulled out) 3 Steel pipe pile (positive electrode) 4 DC power supply

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Isamu Kuroshima 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office (56) References JP-A-59-192129 (JP, A) JP-A Sho 54-31902 (JP, A) JP-A-53-87504 (JP, A) JP-A-53-67903 (JP, A) JP-A-48-11807 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 9/02 E02D 11/00

Claims (1)

(57) [Claims] 1. A method for extracting a plurality of steel members embedded in the ground, wherein one of the steel members is first connected to a negative electrode as an object to be extracted, and another steel member embedded in the vicinity of the steel member. after the steel member by applying a DC voltage by connecting the positive electrode, and connecting the steel member to the positive electrode by applying a DC voltage as well as connected to the negative electrode as a target pull the other steel member, the electrolyte solution contained in the ground Generating hydrogen gas in the vicinity of the steel member by causing electrolysis through the medium, thereby reducing the frictional force of the ground against the pulling out of the steel member, and then pulling out the steel member in its longitudinal direction. A method of extracting a steel member buried underground.