JP4458460B2 - Hole forming method and hole forming apparatus for steel pipe sheet pile - Google Patents

Description

  The present invention relates to a retaining wall technique using a steel pipe for constructing an underground part of a civil engineering or building structure, and thinning from the inside of the steel pipe by an electrolytic corrosion technique and directly cutting with an excavator (shield machine). The present invention relates to a hole forming method and a hole forming apparatus for a steel pipe sheet pile.

Conventionally, as a method for demolishing a reinforced concrete structure, a mechanical destruction method such as a rock drill or a heavy machinery for demolition is used, and in a special case, destruction by an explosive is performed.
However, there have been various problems in the method of dismantling reinforced concrete structures that are exposed to earth pressure and water pressure, such as earth retaining walls built in the ground, and have a risk of collapse due to dismantling. A prominent example is the shield method.

In the shield method, starting and reaching from a vertical shaft at a deep underground location. Due to the large earth pressure and water pressure acting on the earth retaining wall of deep shafts, the structure is generally strong with mud solidified walls etc. solidified with soil cement by connecting reinforced concrete connecting walls or H-shaped steel. It has become.
Conventionally, shield machines from these shafts have been started and reached by injecting chemicals for ground improvement into the ground behind the retaining wall or inserting multiple freeze tubes into the ground to form frozen soil or frozen soil walls. It has been done after constructing a self-supporting protective work to suppress the collapse of the natural ground, and demolishing the retaining wall with human power or heavy machinery for dismantling.

  However, this method has a problem that it takes considerable time and cost to improve the ground. In addition, depending on the ground and depth, it may be difficult to ensure a predetermined strength and water stoppage by improving the ground. In addition, the improvement of these back grounds involved the exposure and release of natural grounds, and there was also a problem from the safety aspect.

  If it is possible to cut and open the retaining wall of the shaft directly with the disk cutter of the shield machine and reach the start, it is economical and safe. However, the retaining wall of the shaft was buried with steel bars and steel as pile core material, and could not be cut with the cutter of the shield machine. In order to solve these problems, there is known a retaining wall that uses a high-strength carbon fiber reinforced plastic as a pile core material in place of reinforcing bars and steel materials, and can be cut with a shield machine using coarse limestone as coarse aggregate. However, since the high-strength carbon fiber reinforced plastic, which is a pile core material, is expensive, there is a problem in economy.

  In order to solve the above-mentioned problem, it is easy to construct a reinforced concrete structure having a part to be destroyed, it is excellent in economy without using expensive members, and can be easily and reliably broken in a short period of time. In the construction method, we provide earth retaining walls that can be cut with a shield machine disk cutter or shield machine excavation route, eliminating the need for protective work in the shaft when starting and reaching the shield method, and ensuring safety Also known is a technique for embrittlement of the temporary wall portion of reinforced concrete by melting the pile core material by electric corrosion for the purpose of shortening the construction period. (Patent Document 1).

JP 2001-280069 A

The first object of the present invention is to weaken a steel pipe sheet pile joint member by erosion during construction of an underground excavation structure, and to shorten the work period while ensuring the safety of construction. It is.
The second purpose is to shorten the electrolytic corrosion time of the joint member of the steel pipe sheet pile.
The third purpose is to enable the steel pipe sheet pile joint member to be efficiently recovered by the excavator.

According to the first aspect of the present invention, the male and female joint members provided on the outer surface of the steel pipe and the steel pipe are respectively hollow members, and the female joint member is attached so as to close the hollow portion of the hollow member by the outer peripheral surface of the steel pipe. The electrode member is inserted with the electrolyte interposed in the steel pipe, and a voltage is applied between the steel pipe and the joint member and the electrode member so that the inner walls of the steel pipe and the joint member are formed. A steel pipe sheet pile hole forming method, wherein the steel pipe sheet pile is destroyed after the anode is melted and weakened.

  According to the first aspect of the present invention, the steel pipe and the joint member provided in the planned fracture portion of the steel pipe sheet pile are dissolved in the electrolyte by anodic dissolution and become brittle. Therefore, the planned fracture portion can be easily maintained while maintaining the strength of the entire structure. A hole can be reliably formed easily.

The invention of claim 2 is to build a water-impervious material on the outside of the steel pipe sheet pile consisting of joint member provided on the steel pipe and the steel pipe outer surface, and each hollow member steel pipe and the male and female coupling members, said female coupling member Is composed of a pair of hollow members attached so as to close the hollow portion of the hollow member by the outer peripheral surface of the steel pipe, and the electrode member is inserted with the electrolyte interposed in the steel pipe, and the steel pipe, the joint member, and the electrode member The steel pipe sheet pile hole forming method is characterized by breaking the steel pipe sheet pile after applying a voltage between the two and anodic dissolution of the inner walls of the steel pipe and joint member.

  According to the invention which concerns on Claim 2, a steel pipe sheet pile without the load of a management surface is formed, without electrolyte flowing out to a surrounding ground.

The invention of claim 3 is a steel pipe formed from a hollow member, a male and female joint member provided on the outer surface of the steel pipe, an electrode member inserted into the steel pipe, an electrolyte filled in the steel pipe, a steel pipe, have a power source for applying a voltage between the male and female coupling member and the electrode member, from the female coupling member is a pair of hollow members mounted to close the hollow portion of the hollow member by the outer peripheral surface of the steel pipe It is the hole formation apparatus of the steel pipe sheet pile characterized by becoming .

  According to the invention of claim 3, since the steel pipe and the joint member provided in the planned fracture portion of the steel pipe sheet pile are dissolved in the electrolyte by anodic dissolution and become brittle, it is easy to break the planned fracture portion while maintaining the strength of the entire structure. And the hole formation apparatus of the steel pipe sheet pile which is easy to destroy reliably can be provided.

The invention according to claim 4 is the hole forming device for the steel pipe sheet pile according to claim 3, wherein the shape of the electrode member inside the steel pipe is projected in the vicinity of the male and female joint members.

  According to the invention which concerns on Claim 4, the electrolytic corrosion can be complete | finished in the substantially same time with the steel pipe and joint member which are in a different distance from an electrode member.

The invention according to claim 5 is the steel pipe sheet pile hole forming device according to claim 3 or 4, wherein the width of the cross section of the female joint member is V-shaped with the welded portion with the steel pipe being wide and narrowing toward the tip. It is.

  According to the invention which concerns on Claim 5, the electrolytic corrosion time can be shortened by expansion of the inflow port of the electrolyte of the said steel pipe and a coupling member.

  Invention according to claim 1: Since the steel pipe and the joint member provided in the planned fracture portion of the steel pipe sheet pile are dissolved in the electrolyte (electrolyte) by anodic dissolution and become brittle, it is easy to break the planned fracture portion while maintaining the strength of the entire structure. And it can make it easy to form a hole reliably.

  Invention which concerns on Claim 2: The steel pipe sheet pile without the load of a management surface is formed, without electrolyte (electrolyte solution) discharging to the surrounding ground by a water-shielding material.

  Invention according to claim 3: Since the steel pipe and the joint member provided in the planned fracture portion of the steel pipe sheet pile are dissolved in the electrolyte (electrolyte) by anodic dissolution and become brittle, the planned fracture portion is maintained while maintaining the strength of the entire structure. It is possible to provide a steel pipe sheet pile hole forming device that can be easily and reliably broken.

  Invention which concerns on Claim 4: By making an electrode member protrude in a joint direction, the electrolytic corrosion can be complete | finished in the substantially same time for the steel pipe and joint member which are in a different distance from an electrode member.

  The invention which concerns on Claim 5: The electrolytic corrosion time can be shortened by expansion of the inflow port of the electrolyte (electrolytic solution) of a steel pipe and a joint member.

1 is a schematic plan view for explaining a state in which joint members of steel pipe sheet piles according to an embodiment of the present invention are connected, and FIG. 2 is a schematic perspective view showing a connection state of the steel pipe shown in FIG. FIG. 3 is a longitudinal sectional view for explaining the principle of an electrolytic corrosion apparatus for steel pipe sheet piles.
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
A steel pipe sheet pile 1 used for a soil retaining method using a steel pipe is composed of a steel pipe 2 and male and female joint members 3 and 4. The steel pipe 2 is attached to the outer side surfaces of the steel pipes 2 juxtaposed in the radial direction along the longitudinal direction of the male and female joint members 3 and 4 by, for example, a method such as welding. They are mechanically connected by fitting 4 together.
The female juxtaposed joint member 3 is composed of a pair of female juxtaposed joint element members 31 having a U-shaped cross section, and forms a hollow portion 3a having a U-shaped cross section in each member 31 when attached to the steel pipe 2. . The male juxtaposed joint member 4 has an O-shaped cross section and is configured to be fitted between a pair of members 31 of the female juxtaposed joint member 3.

The pair of female side-by-side joint element members 31 of the female side-by-side joint member 3 are attached so as to close the hollow portion 3a by the outer surface of the steel pipe 2, and the hollow member of the steel pipe 2 is filled with the electrolyte (electrolyte) 5. .
When the electrode member 6 is provided inside the hollow portion 2c of the steel pipe 2 and a voltage is applied between the hollow member of the steel pipe 2 and the female parallel joint member 3 and the electrode member 6, the steel pipe 2 and the female parallel joint member 3 are provided. A hole is formed in the steel pipe sheet pile 1 by anodic dissolution of the inner wall of the steel pipe sheet pile to weaken the inner wall and destroy the inner wall of the planned destruction portion 1a of the steel pipe sheet pile 1.

In FIG. 1, when a water shielding material (wall) 1b made of soil cement is constructed outside a steel pipe sheet pile 1 made of a steel pipe 2 and male and female joint members 3, 4, the water shielding material 1b is made of an electrolyte (electrolyte). It becomes a water-blocking layer that prevents water loss.
In FIG. 2, the planned destruction portion 1 a of the steel pipe sheet pile 1 is indicated by hatching.

(Punch forming device for steel pipe sheet pile)
FIG. 3 is a longitudinal sectional view of an electrolytic corrosion apparatus for a steel pipe sheet pile in the planned destruction portion 1a of the steel pipe sheet pile.
Based on FIG. 3, the electrolytic corrosion apparatus of the steel pipe sheet pile which is the destruction destruction part 1a (FIG. 2) of the steel pipe 2 which attached the male and female joint member 3 and 4 is demonstrated.
The steel pipe 2 is a hollow member having a thickness that is electrically conductive and has a predetermined strength, and an electrode member 6 is disposed at the substantially center in the hollow part of the steel pipe 2 of the planned fracture portion 1a. The water shielding layer is provided by the water shielding material 7.

Further, an inlet 5a and an outlet 5b of an electrolyte (electrolyte) 5 for anodic dissolution of the inner wall 2a of the steel pipe are provided in the vicinity of the upper part and the lower part in the longitudinal direction of the planned fracture portion 1a of the steel pipe 2, respectively. An electrolyte (electrolytic solution) 5 is supplied into the steel pipe 2 from the inlet 5a, and the hollow member of the steel pipe is interposed between the hollow member of the steel pipe 2 and the electrode member 6 with the electrolyte (electrolytic solution) 5 interposed therebetween. A voltage is applied between the electrode member 6 and the inner wall 2a of the hollow member of the steel pipe is anodic dissolved.
The electrolyte (electrolyte solution) 5 not only supplied into the inlet 5a or al steel tube 2 can be circulated. By supplying the electrolyte (electrolyte solution) 5 in this manner, anodic dissolution is promoted, and the eluate can be discharged and collected outside.

  In this embodiment, electrolyte (electrolyte) inlets / outlets 5a and 5b are provided in the expected fracture portion 1a of the steel pipe 2, but hydrogen by anodic dissolution is preliminarily filled in the steel pipe with an electrolyte containing a cathode depolarizer. It can also be set as the sealing structure which suppresses generation | occurrence | production of gas and does not provide the entrance / exit 5a, 5b.

  Further, an insulating layer can be formed on the inner wall 2a of the steel pipe with a coating made of paint or the like. In this embodiment, the insulating layer is formed so as to cover the conductive material of the steel pipe in the vicinity of the upper part and the lower part in the longitudinal direction of the planned fracture portion 1a of the steel pipe 2, and the steel pipe inner wall 2a other than the part where the insulating layer is formed is made of a conductive material. By using the exposed exposed portion, the insulating layer portion becomes an anodic dissolution preventing portion, and only the exposed portion of the conductive material can be anodic dissolved. By arranging the insulating layer and the exposed portion of the conductive material alternately on the steel pipe inner wall 2a vertically and horizontally, it is possible to dissolve the anode of only the exposed portion of the conductive material in a short period of time, thereby saving power consumption. Can be achieved.

  The steel pipe 2 includes a connecting portion 51 a for connecting to the positive electrode of the DC power source 51, while the electrode member 6 includes a connecting portion 51 b for connecting to the negative electrode of the DC power source 51. The connection part 51b with a negative electrode is provided in the electrode member 6, and this advances the anodic dissolution reaction of the steel pipe inner wall 2a close to the connection part 51b.

  The steel pipe 2 can be an active and easy-dissolving steel pipe that is inexpensive and has strength, but the material of the main pipe is not limited to steel, such as copper, brass, aluminum, zinc, magnesium, etc. Any material can be selected as appropriate as long as it is easily dissolved in the active material.

  Further, as the material of the steel pipe 2, a material composed of a plurality of different conductive materials or an alloy made of different metal materials can be used. By using these materials, a portion with high electrolytic activity is preferentially dissolved, and therefore, the material can be made brittle in a shorter time than when the whole is dissolved.

  For the electrode member 6, for example, brass can be selected. Further, a non-metallic conductive material such as carbon may be used. In the embodiment of FIG. 3, a solid brass bar is used as the electrode material 6, but strength is not sought because of the properties as the electrode member 6, so a hollow round bar, square bar, or thin brass plate It may be.

Next, the reaction of embrittlement of the steel pipe 2 by anodic dissolution will be described.
While connecting the positive electrode of the DC power source 51 to the steel pipe 2 and connecting the negative electrode to the electrode member 6, a voltage is applied between the steel pipe 2 and the electrode member 6. As a result, the metallic iron Fe loses electrons and becomes iron ions, which are dissolved in the electrolyte. In addition, water in the electrolyte is electrolyzed to generate hydrogen gas, and hydroxyl ions (hydroxide ions) are generated from the water. Then, iron ions and hydroxyl ions react to form iron hydroxide precipitates. By applying voltage to the electrode member 6 while continuing to supply the electrolyte, the inner wall 2a of the steel pipe 2 is melted (anodic dissolution), thereby gradually reducing the thickness of the steel pipe 2 and weakening the steel pipe 2. be able to.

  In this method, since the reaction for dissolving metallic iron by anodic dissolution is performed on the inner wall of the steel pipe 2, the surrounding concrete is not affected, and the surrounding concrete is not affected. Thus, it is possible to efficiently promote anodic dissolution and weaken the steel pipe 2.

(Female parallel joint member and electrode member)
FIG. 4 is a flowchart of the experimental electrolytic corrosion system, and FIG. 5 is a schematic plan view of the steel pipe portion shown in FIG.
Steel top cover is by plywood 6d and sponges 6c, the lid is a steel pipe lower even plywood 6d and sponge 6c.
The steel pipe is conductive pole member 6 is provided between the upper and lower, by water pump 9 in the electrolyte reservoir, through the liquid feed pipe 5d, electrolyte in the hollow portion of the steel pipe 2 in which the electrode member 6 is located Fill with liquid (saline) 5. Moreover, it is set as the structure which discharges the electrolyte solution 5 to an electrolyte solution storage tank by the drainage pipe 5c.
A male side-by-side joint member (O-type joint material) 4 and a female side-by-side joint member 3 having a hollow portion 4 c are welded to the outside of the steel pipe 2. The female juxtaposed joint member 3 is composed of a pair of female juxtaposed joint element members 32 having a V-shaped cross section, and forms a hollow portion 3d having a V-shaped cross section in each member 32 while being welded to the steel pipe 2. The male juxtaposed joint member 4 is configured to be fitted between a pair of members 32 of the female juxtaposed joint member 3. The electrode member 6 is provided with protruding portions 6b that protrude toward the pair of members 32 of the male side-by-side joint member 4 and the female side-by-side joint member 3d.
The steel pipe 2 is connected to the positive electrode of the DC power supply 51, and the electrode member 6 is connected to the negative electrode of the DC power supply 51, whereby the anodic dissolution reaction of the inner wall of the steel pipe 2 and the inner walls of the male and female joint members 3 and 4 is performed. To advance.
The outside of the steel pipe 2 is filled with mortar 1b so that the electrolyte does not escape to the surrounding ground.

An embodiment of the female juxtaposed joint member and the electrode member will be described with reference to FIG.
The inlet of the electrolytic solution 5 at the boundary between the hollow portion of the steel pipe 2 and the pair of members 32 of the female side-by-side joint member 3 is widened by a V-shaped cross section.
Due to the enlargement of the inlet of the female juxtaposed joint element member 32, the electrolyte 5 quickly flows from the hollow portion of the steel pipe 2 to the hollow portion 3 d of the female juxtaposed joint element member 32, and the electrolytic corrosion time of the female juxtaposed joint member 3 Can be shortened.

  Further, by forming the shape of the electrode member 6 inside the steel pipe 2 so as to protrude in the vicinity of the pair of female parallel joint element members 32, the protruding portion 6 b of the electrode member 6 and the female parallel joint member 3 Since the distance between the pair of element members 32 is shortened, the electrolytic corrosion near the element members 32 is preceded, and the electrolytic corrosion time of the female side joint member 3 is shortened. The same can be said for the protruding portion 6b of the electrode member 6 on the male side joint member 4 side.

(Shield construction shaft)
FIG. 6 is a cross-sectional view of the shaft of the shield method. In this shield construction method, the start shaft 50 and the reach shaft having the temporary wall portion 10 that can be changed to a weaker structure than the surrounding structure are respectively constructed at the start position and the reach position.
Since the reaching shaft is the same as the starting shaft except that the temporary wall portion 10 is directed to the starting shaft 50 side, the illustration is omitted.
After this construction, first, the temporary wall portion 10 of the start shaft 50 is weakened by anodic dissolution described above, and then the shield machine 30 is driven from the start shaft 50 to cut and destroy the temporary wall portion 10. Then, the shield tunnel 20 is constructed while the shield machine 30 is advanced toward the arrival shaft, and when the shield machine 30 reaches the arrival shaft, the temporary wall portion 10 of the arrival shaft is weakened by the above-described anode dissolution. Thereafter, the temporary wall portion 10 is cut and broken by the shield machine 30 to be connected to the shield tunnel 20. In this shield construction method, since the start and reach shafts that can be cut by the disk cutter 30a of the shield machine 30 are used, it is possible to ensure safety, eliminate the need for protective work, and shorten the construction period.

That is, in the temporary wall part 10 in this shield method, what used the electrode member loosely inserted in the inside of the steel pipe 2 is used.
While supplying the electrolytic solution to the inside of the steel pipe 2, it is possible to apply a voltage to the steel pipe sheet pile 1 and the electrode member 6 so that the steel pipe sheet pile 1 is anodic dissolved and weakened.

  The start shaft 50 is excavated to the depth of the designed shield tunnel, protected from the surrounding soil water pressure by a steel pipe sheet pile, and the temporary wall portion 10 is provided in a portion to be cut and broken by the shield machine 30.

  Following the construction of the shaft, the DC power source 51 and the electrolytic solution tank 40 are installed on the ground in preparation for the weakening of the temporary wall portion 10 in parallel with the assembly of the shield machine 30. Then, the electrolyte solution supply port and the discharge port of the temporary wall portion 10 are connected to the solution feed pipes 41 a and 41 b via the electrolyte solution delivery pump 42. Moreover, a voltage is applied between the steel pipe sheet pile 1 and the electrode member connected via the electric wire 51c by the DC power source 51.

  Next, the shield machine 30 is temporarily excavated and inserted into the main frame, and while maintaining the pressure, the anode wall of the temporary wall 10 is dissolved by applying a DC voltage and circulating the electrolyte, thereby making the temporary wall 10 brittle. I do. In the temporary wall part 10 which has been made brittle, the pressure is held by the shield machine 30, so that the external earth pressure can be prevented from collapsing and can be constructed safely.

At this time, iron hydroxide is recovered in the electrolytic cell 40 as an eluate of the steel pipe sheet pile 1 by the circulated electrolyte solution. The recovered iron hydroxide is separated from the electrolyte such as moisture and salt by the separator 43 and disposed of as waste or reused after appropriate treatment.
After confirming that the embrittlement is completed so that cutting is possible, the shield machine 30 is started and the temporary wall portion 10 is directly cut by the disk cutter 30a.

Moreover, as shown in FIG. 7, the female side joint member 33 which consists of a solid member provided in the destruction planned part 1a of the steel pipe sheet pile 1, for example, a C-type joint member, is provided with a lateral slit 3b in its longitudinal direction. By providing a plurality of locations at predetermined intervals along the steel pipe 2, even if the female parallel joint member 33 is cut off by electrolytic corrosion of the steel pipe 2, the joint member after electrolytic corrosion is cut at the slit portion by a recovery device of an excavator (shield machine). Thus, it can be decomposed into a size that can be recovered.
Since the steel pipe 2 and the O-type joint member 4 are hollow members, they are weakened by electrolytic corrosion.

It is a schematic plan view for demonstrating the state which the coupling member of the steel pipe sheet pile which is 1st Embodiment of this invention connects. It is a schematic perspective view which shows the connection state of the steel pipe shown by FIG. It is a longitudinal cross-sectional view of the electrolytic corrosion apparatus of a steel pipe sheet pile. It is a flowchart of an element experiment electric corrosion system. It is a top view for demonstrating schematically 2nd Embodiment of the electrode member shown in FIG. 4, and a female parallel joint member. It is sectional drawing which shows the shaft of a shield construction method. It is a schematic perspective view for demonstrating schematically 3rd Embodiment of a female juxtaposed joint member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steel pipe sheet pile, 1a ... Planned destruction part, 1b ... Water shielding material (wall), 2 ... Steel pipe (hollow member of steel pipe), 2a ... Inner wall, 3 ... Female parallel joint member, 31, 32 ... Pair of female parallel Joint element member, 3a, 3d ... hollow part of joint member, 3b ... slit, 4 ... male side-by-side joint member, 5 ... electrolyte (electrolyte), 6 ... electrode member, 7 ... water shielding material (bottom), 8 ... Insulating part, 10 ... Temporary wall part, 30 ... Shield machine, 51 ... Power supply.

Claims (5)

  A male and female joint member provided on the outer surface of the steel pipe and the steel pipe are each a hollow member, and the female joint member is a set of hollow members attached so as to close the hollow portion of the hollow member by the outer peripheral surface of the steel pipe. The electrode member was inserted in the state where the electrolyte was interposed in the steel pipe, and a voltage was applied between the steel pipe and the joint member and the electrode member, and the inner walls of the steel pipe and the joint member were anodic dissolved and weakened. Then, the steel pipe sheet pile is destroyed, The hole formation method of the steel pipe sheet pile characterized by the above-mentioned.   A water shielding material is constructed on the outer side of the steel pipe sheet pile composed of the joint member provided on the steel pipe and the steel pipe outer surface, and the steel pipe and the male and female joint members are each hollow members, and the female joint member is formed by the outer peripheral surface of the steel pipe. It consists of a set of hollow members attached so as to close the hollow part of the hollow member, and the electrode member is inserted with the electrolyte interposed in the steel pipe, and a voltage is applied between the steel pipe and the joint member and the electrode member. And the steel pipe sheet pile hole forming method characterized by destroying the steel pipe sheet pile after the inner walls of the steel pipe and the joint member are anodic dissolved and weakened.   A steel pipe formed from a hollow member, a male and female joint member provided on the outer surface of the steel pipe, an electrode member inserted into the steel pipe, an electrolyte filled in the steel pipe, and a steel pipe and male and female joint member and electrode member And the female joint member is composed of a pair of hollow members attached so as to close the hollow portion of the hollow member by the outer peripheral surface of the steel pipe. Sheet pile hole forming device.   The hole formation apparatus of the steel pipe sheet pile of Claim 3 which made the shape of the electrode member inside the said steel pipe protruded in the joint member vicinity direction of the said male and female. The steel pipe sheet pile hole forming device according to claim 3 or 4, wherein a width of a cross section of the female joint member is V-shaped so that a welded portion with the steel pipe is wide and the tip is narrowed.

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