JP2004308120A - Removable timbering member by electrocorrosion and its removing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely, surely, partially, and easily remove a steel material (or an anchor) such as a lock bolt without having influence on an underground structural skeleton such as a permanent tunnel when constructing an underground structure such as a tunnel. <P>SOLUTION: An electrode bar 8 becoming an opposite pole to a hollow lock bolt 4 is arranged in the hollow lock bolt 4 inserted into the ground, and an electrolyte 15 is injected, and a hollow timbering member is electrolytically corroded by carrying an electric current between the hollow lock bolt and the electrode bar. After thinning the hollow lock bolt by electrocorrosion, the lock bolt is substituted with the electrolyte, and a chargeable filler is filled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a support member such as a rock bolt or a steel member that supports a wall surface of an underground structure such as a tunnel or the like, particularly a support member having a structure that can be easily removed by electrolytic corrosion, and a method for removing the support member.
[0002]
[Prior art]
Conventionally, in a support method for a wall surface of an underground structure such as a tunnel, steel materials (or anchors) such as rock bolts are radially radiated almost orthogonally to the wall surface of the underground structure to form a part of the primary support. When removing a part or all of the steel material (or anchor) such as the rock bolt after the concrete lining of the secondary lining is completed, it will be installed when the steel material (or anchor) such as the lock bolt is replaced or pulled out. This will affect the structure of underground structures such as tunnels.
[0003]
Therefore, in order to prevent these effects from occurring, the construction cost is greatly increased by increasing the size of other supports and adopting the auxiliary construction method. In addition, if you do not use aggressive support construction or auxiliary construction methods, and you do not want to use temporary support members in the ground, you can secure the ground site and set the range of section ground rights to steel materials such as rock bolts ( Or, it has been necessary to expand to the end position of the anchor), and a significant increase in the project cost was inevitable.
[0004]
On the other hand, when placing a fiber reinforced bolt such as FRP that can be demolished instead of a steel material (or anchor) such as a rock bolt, it is necessary to obtain approval from the landowner because the reinforced bolt in the site is located. Become. In addition, when fiber reinforced bolts are demolished by excavation of the underground structure such as a tunnel in a main tunnel, it will be affected.
[0005]
[Problems to be solved by the invention]
The problem of the present invention is that the construction of an underground structure such as a tunnel is complete, reliable and partial to a steel material (or anchor) such as a lock bolt without affecting the structure of the underground structure such as a tunnel. Can be removed easily, and as a result, the land acquisition and division ground rights are set to the minimum necessary, the land cost for the project is reduced, negotiations with land owners and the impact on the neighborhood are advantageous, and underground structures The object is to provide a support member and a method for removing the support member that enable smooth execution of the construction business.
[0006]
[Means for Solving the Problems]
According to the present invention, an electrode serving as a counter electrode is disposed in a hollow support member inserted into the ground, and an electrolyte is injected to energize between the hollow support member and the electrode. The hollow support member is eroded, and the hollow support member is eroded and removed.
[0007]
If the electrolyte solution immerses only a part of the inner surface of the hollow support member, the hollow support member can be partially removed. For this purpose, a part of the inner surface of the hollow support member may be left with an insulating coating, or the electrolytic solution may be injected only in a part of the hollow support member.
[0008]
Filling the hollow support member thinned by electrolytic corrosion with the electrolytic solution by replacing it with the electrolytic solution can prevent underground contamination due to leakage of the electrolytic solution and shorten the energization time required for electrolytic corrosion. You can also save consumption.
[0009]
The hollow support member is not limited to a steel material such as a rock bolt, as long as it is a member that galvanizes.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
In the present embodiment, as shown in FIG. 1, the present invention is applied to a lock bolt (steel material) for supporting the primary supporting shotcrete 1 serving as the outer wall surface of the underground structure after the construction.
[0011]
First, after drilling an anchor insertion hole 3 with a rock drill 2 as shown in FIG. 2 so as to penetrate the primary supporting shotcrete 1, a hollow is formed in the anchor insertion hole 3 as shown in FIG. A hollow lock bolt 4 which is a support member is inserted, and its base end portion 4 a is projected from the surface of the primary support spray concrete 1 and fixed with a nut 5. The distal end 4b of the hollow lock bolt 4 is closed, but the proximal end is open.
[0012]
Next, a filler 7 is filled in the gap 6 between the anchor insertion hole 3 and the hollow lock bolt 4 as shown in FIG. Next, as shown in FIG. 5, after inserting and installing the electrode rod 8 which is the opposite electrode to the hollow lock bolt 4, the base end of the hollow lock bolt 4 and the base end of the electrode rod 8 are plus / minus Are connected, and the distal end portions of the injection tube 11 and the discharge tube 12 are inserted and installed in the proximal end portion of the hollow lock bolt 4. Moreover, after applying the waterproof sheet 13 to the primary supporting spray concrete 1 surface so that the circumference | surroundings of the hollow lock bolt base end part 4a fixed with the nut 5 may be covered, as shown in FIG. A housing 14 is constructed. At that time, the conducting wires 9, 10, the injection tube 11, and the discharge tube 12 are drawn out from the hole 14 a of the housing 14.
[0013]
Next, as shown in FIG. 7, while discharging air from the hollow lock bolt 4 with the discharge tube 12, an electrolyte solution 15 is injected into the hollow lock bolt 4 through the injection tube 11. A current is applied between the hollow lock bolt 4 and the electrode rod 8 by 9 and 10, and the hollow lock bolt 4 made of steel is electrolytically eroded from the inside.
[0014]
After the hollow lock bolt 4 is thinned by electrolytic corrosion, as shown in FIG. 8, while discharging the electrolytic solution 15 in the hollow lock bolt 4 from the discharge tube 12, the chargeable filler 16 is placed in the hollow lock bolt 4. It is injected to replace the electrolytic solution 15.
[0015]
As shown in FIG. 9, the current-carrying wires 9 and 10, the injection tube 11 and the discharge tube 12 drawn out from the hole 14 a of the housing 14 are removed, and thereafter, the remaining portion of the hollow lock bolt 4 due to the natural potential of the chargeable filler 16. Disappear. In addition, the cavity which arises after the loss | disappearance of the hollow lock bolt 4 is filled with a filling material as needed.
[0016]
Next, an embodiment in which the hollow lock bolt 4 is partially eroded will be described.
In the example shown in FIG. 10, the inner surface of the hollow rock bolt 4 is provided with an insulating coating 17 except for a portion 4c surrounded by an elliptical line, and only this portion 4c is immersed in the electrolytic solution to cause electrolytic corrosion. It is.
[0017]
In the example shown in FIG. 11, an electrolyte limited injection region surrounded by an elliptical line is defined in the hollow rock bolt 4 by, for example, a partition wall 18, and electrolytic solution is injected only into this region to cause electrolytic corrosion. Is.
[0018]
FIG. 12 shows an example in an urban tunnel, FIG. 13 shows an example in an underground structure, and FIG. 14 shows an example in an earth retaining structure, extending outside the construction site (outside the area indicated by the broken line). It represents that the hollow lock bolt 4 is eliminated by electrolytic corrosion as shown by hatching.
[0019]
As mentioned above, although the Example applied to the hollow rock bolt which is steel materials was described, if this invention is a hollow support member which carries out electrolytic corrosion, it can apply regardless of the material, a use, and a construction place.
[0020]
【The invention's effect】
As described above, according to the present invention, since the hollow support member is eroded and removed from the inside thereof, the underground structure such as a tunnel is not affected when the underground structure such as a tunnel is constructed. Steel materials (or anchors) such as rock bolts can be easily removed even if they are complete, reliable and partial.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state after construction of primary support shotcrete in one embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a step of drilling an anchor insertion hole.
3A is a cross-sectional view of a state in which a hollow lock bolt is inserted into an anchor insertion hole, and FIG. 3B is an end view.
FIG. 4A is a longitudinal sectional view of a state where a filler is filled in a gap between an anchor insertion hole and a hollow lock bolt, and FIG. 4B is a transverse sectional view.
FIG. 5 is a cross-sectional view showing a state in which an electrode rod, a conducting wire, an injection tube, and a discharge tube are set with respect to a hollow lock bolt.
FIG. 6 is a cross-sectional view of a state in which a housing of the present structure is constructed.
FIG. 7 is a cross-sectional view of a state in which an electrolytic solution is injected into the hollow rock bolt and energized to cause the hollow rock bolt to galvanize.
FIG. 8 is a cross-sectional view of a state where a charging filler is injected in place of an electrolytic solution.
FIG. 9 is a cross-sectional view showing a state in which the hollow lock bolt disappears due to the natural potential of the chargeable filler.
FIG. 10 is a cross-sectional view showing an example in which a part of the inner surface of the hollow lock bolt is left with an insulating coating and only this part is subjected to electrolytic corrosion.
FIG. 11 is a cross-sectional view showing an example in which an electrolyte limited injection region is partitioned in a hollow rock bolt, and only this region is subjected to electrolytic corrosion.
FIG. 12 is a cross-sectional view showing an embodiment in an urban tunnel.
FIG. 13 is a cross-sectional view showing an embodiment of an underground structure.
FIG. 14 is a cross-sectional view showing an embodiment of the earth retaining structure portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Primary support spray concrete 2 Rock drill 3 Anchor insertion hole 4 Hollow lock bolt 4a Base end part 4b of hollow lock bolt 5 End of hollow lock bolt 5 Nut 6 Cavity 7 Filler 8 Electrode rod 9/10 Conduction wire 11 Injection tube 12 Discharge tube 13 Waterproof sheet 14 Housing 14a Housing hole 15 Electrolytic solution 16 Chargeable filler 17 Insulation coating 18 Partition

Claims (11)

The hollow support member inserted in the ground is provided with an electrode serving as a counter electrode, and an electrolytic solution is injected to energize between the hollow support member and the electrode. A support member that can be removed by electrolytic corrosion, characterized in that 2. The support member that can be removed by electrolytic corrosion according to claim 1, wherein the electrolyte solution immerses only a part of the inner surface of the hollow support member. 3. The electrolytic corrosion according to claim 2, wherein the inner surface of the hollow support member is provided with an insulating coating so as to leave a part, and the electrolytic solution immerses the inner surface of the hollow support member without the insulating coating. Support member that can be removed. 3. The support member that can be removed by electrolytic corrosion according to claim 2, wherein the electrolytic solution is injected only in a part of the hollow support member. 5. A removable support by electrolytic corrosion according to any one of claims 1 to 4, wherein the hollow support member thinned by electrolytic corrosion is filled with a chargeable filler replaced with an electrolytic solution. Element. The hollow support member is a steel material such as a lock bolt, and the support member that can be removed by electrolytic corrosion according to any one of claims 1 to 5. An electrode serving as a counter electrode is disposed in the hollow support member inserted into the ground, and an electrolytic solution is injected to energize the hollow support member between the hollow support member and the electrode. A method for removing a support member, characterized in that: 8. The method of removing a support member according to claim 7, wherein the electrolytic solution immerses only a part of the inner surface of the hollow support member and causes only a part of the hollow support member to be eroded. 9. The method of removing a support member according to claim 8, wherein a part of the inner surface of the hollow support member is left with an insulating coating, and a portion without the insulating coating is eroded. The method for removing a support member according to claim 8, wherein the electrolytic solution is injected only in a part of the hollow support member, and the part is electrolytically eroded. The method of removing a support member according to any one of claims 7 to 10, wherein the hollow support member is thinned by electrolytic corrosion, and then is replaced with an electrolytic solution and filled with a chargeable filler.

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