JP2007154441A - Concrete chipping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a relationship between the depth of insulating water and such a between-electrodes distance that concrete can be surely crushed by high-voltage pulse discharge, in a method for chipping a surface of a concrete structure. <P>SOLUTION: Two discharge electrodes 13+ and 13- are erected at the between-electrodes distance L in a tubular container 11 which is installed on a concrete surface 1; the inside of the tubular container 11 is filled with the insulating water so that the water depth can be 1/2×L or more; and a high-voltage pulse, which is imparted to the discharge electrode 13+, is propagated to the inside from the concrete surface 1, so that the concrete surface 1 between the discharge electrodes 13+ and 13- can be chipped like a thin layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a concrete suspension method, and sets the water depth of the insulating water so that concrete crushing by high voltage pulse discharge can surely occur, and can efficiently hang a predetermined range of the surface of existing reinforced concrete concrete. The concrete made possible relates to the method of suspension.

  Conventionally, a rock or concrete crushing method using high-voltage pulse discharge has been proposed (see Patent Document 1). The concrete crushing operation using this type of high-voltage pulse discharge is performed by, for example, bringing a discharge terminal and a ground terminal, which are arranged at a predetermined distance, into contact with a concrete surface covered with an insulating fluid, and then applying a high-voltage pulse to the discharge terminal side. Is applied, and the surface of the concrete in contact with the discharge terminal and the ground terminal is crushed over a predetermined range. The principle of crushing concrete by this high voltage pulse discharge is that water that does not normally act as an insulator but acts as an insulator when a high voltage pulse is applied (hereinafter referred to as a conductor in this specification). However, when the concrete surface is filled with water used as an insulator during high voltage pulse action, it is called “insulating water.” As a result, the discharge passes through the interior of the concrete containing fine air bubbles and the discharge path. It consists of a mechanism in which the inside becomes high-pressure plasma and the concrete is crushed.

  Also, in order to carry out the concrete wall hanging work, water is sprayed onto the concrete wall surface by the shower nozzle, the water flows through the concrete wall surface like a waterfall, and the wall surface is always covered with water. A method of crushing a concrete wall surface by carrying out high voltage pulse crushing has also been proposed (see Patent Document 2).

  In this specification, for cored crushing operations such as crushing large rocks or concrete into small blocks, the specific range of the concrete surface is a thin layer in the range of several mm to several tens of cm. The work of breaking up into pieces and crushing them off is called "Hatsuri". Therefore, in the present specification, terms such as crushing, hanging, crushing, hulling, etc. are used almost synonymously.

JP-A-9-119283. Japanese Patent Laid-Open No. 11-47625.

  In Patent Document 1, diesel oil, water, seawater, grease, hydraulic oil, or the like is used as an insulating fluid, and the standing electrode is configured to advance toward the inside of a rock or the like to be crushed. And, the insulating fluid is stored in the crushed space, and continuous crushing work is performed, but when concrete is supposed to be suspended, etc., it is cost to use water as an insulating material of high voltage pulse, It is preferable in terms of convenience.

  By the way, at present, when water is used as an insulator and concrete is suspended by a high voltage pulse, what level of water should be secured on the concrete surface, what is the distance between terminals and the water depth? It is not known whether or not there is a correlation, and it has not been clarified so far how much chipping can be performed. For example, as shown in Patent Document 2, it is expected that the insulation effect by the flowing water is extremely low as long as the water flows along the concrete wall surface. In other words, when the water depth is shallower than the distance between the discharge electrodes, it is not possible to secure an effective insulation length between the electrodes in the water, and the water and the water surface (interface) are discharged and the concrete cannot be crushed. It is considered. Moreover, it is preferable to hold the minimum water required for high-voltage pulse crushing for concrete such as a wall surface and a ceiling surface as shown in Patent Document 2 even in the case of a hanging work. Thus, it is desired that the concrete be suspended while keeping the minimum possible water depth from the concrete surface.

  In general, since it is a reinforced concrete structure that is subject to such a lifting operation, usually, in order to remove deterioration or deterioration factors that occur in reinforced concrete at a predetermined cover position from the concrete surface, The lifting work often removes concrete up to a depth of several millimeters to several centimeters from the position of the reinforcing bar at the cover position. That is, in the suspending operation, it is required to expose the main reinforcing bar and the shear reinforcing bar closest to the concrete surface and to hang several mm to several cm below the reinforcing bar.

  By the way, the mechanism of concrete suspension by the above-mentioned high-voltage pulsed electric discharge crushing method is assumed in the case of unreinforced concrete. When working, the reinforcing bar is a good conductor, so depending on the terminal position of the discharge electrode in contact with the concrete surface, the nearest reinforcing bar becomes the discharge path, the pulse current is grounded through the reinforcing bar, and the concrete is crushed. The problem of not being able to occur.

  Therefore, the object of the present invention is to solve the problems of the conventional techniques described above, and when the discharge electrode is installed on the concrete surface at a predetermined distance and the concrete surface is covered with water as an insulator, the concrete It is intended to provide a method of suspending concrete in which the depth of water at which suspending can be performed is clarified and the suspending operation considering the arrangement of reinforced concrete structures can be performed efficiently.

  In order to achieve the above object, according to the present invention, as a concrete suspending method, a discharge electrode is erected at a distance L between electrodes in a cylindrical container installed on the concrete surface. Fill with insulating water so as to be ½ × L or more, propagate a high voltage pulse applied to the discharge electrode from the concrete surface to the inside, and suspend the concrete surface between the discharge electrodes in a thin layer shape. It is characterized by.

  At this time, it is preferable to prevent leakage of the insulating water by interposing a sealing member between a lower end periphery of the cylindrical container and the concrete surface.

  On the other hand, against the concrete wall surface, the cylindrical container having a cylindrical length of ½ × L or more with respect to the interelectrode distance L of the discharge electrode installed inside was pressed toward the concrete wall surface. Installed in a state, the cylindrical container is filled with insulating water, a high voltage pulse applied to the discharge electrode is propagated from the concrete surface to the inside, and the concrete wall surface between the discharge electrodes is suspended in a thin layer. It is characterized by that.

  In these cases, the distance L between the electrodes is equal to the spacing between the reinforcing bars arranged in the concrete, and the reinforcing bars are straddling the reinforcing bar embedded portion so that the reinforcing bars are located at the center of the inter-electrode distance L. It is preferable that the discharge electrode is brought into contact with the concrete surface or the wall surface, and the cover concrete of the reinforcing bars is successively attached in a thin layer.

  According to the present invention, high-voltage pulse crushing can be surely generated on the concrete side by the insulating water stored in the container in the suspension work, and an efficient concrete can be carried out.

  Moreover, also in a reinforced concrete structure, in high voltage pulse crushing, it can prevent that a pulse voltage short-circuits a reinforcing bar, and there exists an effect that the concrete can be reliably suspended.

  Hereinafter, the concrete of the present invention will be described with reference to the accompanying drawings as the best mode for carrying out the suspension method.

  FIG. 1 is an example of a concrete suspension device (hereinafter simply referred to as a suspension device 10) used in the concrete suspension method of the present invention, so that the installation state of discharge electrodes in the main body of the suspension device 10 can be understood. 1 is a schematic overall configuration diagram showing a part of the apparatus in cross section. As shown in the figure, the main body portion of the suspension device 10 includes a cylindrical container 11 that is placed on the concrete surface 1 to be suspended and filled with insulating water 12, and the cylindrical container 11 The two discharge electrodes 13 held by a support frame (not shown) are installed at a predetermined interval. In the present embodiment, the discharge electrode 13 is composed of a self-supporting rod-like body in which the periphery of a φ5 mm copper wire constituting the terminal tip 13a is insulated and coated with a high-density polyethylene resin coating material 13b. In this embodiment, a known high voltage pulse having a high voltage power source of about 200 kV and 400 kV as a high voltage pulse generation source and a capacitor having a charge capacity that can be applied to the target using the high voltage power source as a predetermined pulse voltage. A generator 5 is used.

  The terminal tips 13a of the two discharge electrodes 13 (the anode electrode terminal 13+ and the cathode electrode terminal 13-) connected to the conducting wire 6 derived from the known high voltage pulse generator 5 are separated from the concrete surface 1 by a predetermined distance. Impact force generated by discharging high voltage pulses generated at a certain time interval from the anode terminal 13+ side to the concrete surface 1 and conducting the pulse current through the concrete to the cathode terminal 13- side. Is propagated in the concrete, the concrete surface 1 up to a predetermined width and depth can be peeled into a thin lump and crushed between the two discharge electrodes 13.

  The diameter of the cylindrical container 11 that accommodates the discharge electrode 13 can be determined according to the distance L between the terminals of the discharge electrode 13 that defines the range of suspension. As described above, as for the height of the container, it is important that the insulating water 12 as an insulator is ensured by a predetermined depth D so that the concrete side is reliably crushed.

  Therefore, in the present invention, a preferable relationship between the inter-terminal distance L of the discharge electrode 13 and the depth D of the insulating water 12 stored in the cylindrical container 11 was determined by a concrete crushing experiment using a plurality of cases. The discharge voltage at this time is 400 kV, and the results obtained by changing the water depth from 12 to 230 mm with respect to the distance between terminals of 20 to 240 mm are shown in FIG. As shown in the figure, it was confirmed that the discharge can be suspended if the relationship of D = 1/2 × L is established between the inter-terminal distance L and the water depth D.

  This experiment shows that the concrete surface 1 is covered with water, the high voltage pulse discharge is surely propagated inside the concrete, and the concrete part that becomes the discharge path is crushed so that the necessary and sufficient water depth can be secured. It is preferable to set the dimensions. Specifically, it is preferable to make the dimensions such that a water depth of about ½ times the distance L between the discharge electrodes can be secured. In addition, in order to minimize the risk of damage due to a shock wave that has propagated in water during crushing, the cylindrical cross-sectional shape is preferably a cylindrical shape having no corners or the like.

  On the other hand, a sealing member 20 is provided at the lower end of the cylindrical container 11 over the entire lower end. As shown in FIG. 1, when the insulating water 12 is stored in the interior, it is important that the sealing member 20 is in close contact with the concrete surface 1 in order to prevent water leakage from the lower end. come. Therefore, the thickness of the cylindrical container 11 is such that it can withstand the above-described shock wave, and its own weight is increased to the extent that the adhesion of the seal member 20 to the concrete is improved by the self-weight action of the entire container. It is also preferable to set to.

  In this embodiment, a silicone resin is used as the sealing member 20 as an elastic molding member having a material that can be deformed following the unevenness of the concrete surface 1. For example, a non-vulcanized butyl rubber that exhibits self-adhesiveness is used. Use various materials capable of closing the gap between the cylindrical container 11 and the concavo-convex concrete surface 1 such as soft synthetic rubber, various soft rubber elastomers, urethane elastomers, gel-like soft urethane resins, etc. Can do.

  In addition, a water supply pipe (not shown) is piped in the cylindrical container 11, and the insulating water 12 stored in the external water storage container (not shown) is operated by an external pump or the like prior to the crushing operation. Is supplied to a predetermined water depth in the cylindrical container 11. After the crushing operation, the insulating water 12 mixed with the concrete fragments in the cylindrical container 11 is returned to the external water storage container again.

  The insulating water 12 stored in the cylindrical container 11 is based on tap water, and is preferably added with a predetermined proportion of a thickener to slightly increase the viscosity of the water (hereinafter, this water is referred to as viscous water 12). Called). As a result, the amount of viscous water flowing out of the gap between the lower end of the cylindrical container 11 that contacts the concrete surface 1 and the suspension surface can be reduced. In this embodiment, the viscous water 12 is preferably produced so that a thickener is added to the tap water so that the J funnel flow time is 5 to 15 seconds.

  As the thickener, a cellulose-based water-soluble polymer, an acrylic polymer, a vegetable polymer material, and the like that are easily dissolved by adding to the tap water used are suitable. Needless to say, normal tap water can be used without adding a thickener, as long as the concrete surface 1 is smooth and the water-tightness of the seal member 20 can be sufficiently secured.

  Next, FIG. 2 is an explanatory view showing an example in which the suspension device 10 is applied to the suspension work of the concrete wall surface 7. As shown in the figure, the cylindrical container 11 has a water-tight removable lid 15 for storing viscous water 12 therein. The cylindrical container 11 covered with the lid 15 and having a width D (=> 1/2 L) with respect to the distance L of the discharge electrode 13 is anchored to the concrete wall 7 via the fixed band 8. Held in part 9. At this time, in order to fill the inside with the insulating water 12, a water supply pipe (not shown) is connected to the upper part of the container, and an external pump and an external water storage container are provided in the water supply pipe. In this embodiment, the cylindrical container 11 is fixed by the fixing band 8. However, as another fixing mechanism for fixing the cylindrical container 11 to the wall surface 7, for example, a boom tip attachment of a heavy machine capable of performing various operations by boom operation. It is also possible to provide a gantry on which the cylindrical container 11 is mounted and to arrange the cylindrical container 11 on the gantry on the concrete wall surface 7 as a target by an appropriate pressing force by a boom operation.

[Hanging work in reinforced concrete structures]
In the state where the relationship between the distance L between the discharge electrodes and the depth D of the insulating water 12 is maintained as described above, FIG. 4 and FIG. The description will be given with reference.
Usually, in a reinforced concrete structure, the reinforcing bars (the main reinforcing bars 30 and the distribution reinforcing bars 31) ensure a cover of 30 mm or more. When the cover portion is to be hung, the position of the reinforcing bar in the concrete structure is generally unknown in appearance. Therefore, prior to the hanger operation, the reinforcing bars 30 and 31 located at the end of the hanger range are used as a known reinforcing bar detector. Check the position and cover (reinforcing bar depth) in advance (for example, a product name: a device such as a profometer). Then, the design bar arrangement pitch p is confirmed from the detection position, the distance equal to the bar arrangement pitch p is set as the discharge electrode interval L, and the suspension work in the range shallower than the concrete cover depth from the position shown in FIG. I do. FIG. 2B is a sectional view of the two discharge electrodes 13 arranged from the side. The concrete between the two discharge electrodes 13 has a long and narrow outer shape with the distance between the electrodes as the major axis, the outer width with the minor axis as shown in FIG. It is crushed into a shape like this. The crushing depth is equal to or less than the cover thickness when the inter-electrode distance L is set to the interval between the reinforcing bars 30 and 31.

  Thereafter, as shown in FIGS. 5A and 5B, the discharge electrode 13 is moved at a predetermined interval in the direction of the arrow, and high voltage pulse crushing is performed, for example, by performing several times of concrete crushing work. As shown in FIG. 4 (c), among the reinforcing bars 30, 31 arranged vertically and horizontally, the concrete covering portions on both sides of the main reinforcement 30 shown in FIG. You can hang up.

  6 and 7 show an embodiment in which concrete is crushed to a deeper position (two-dot chain line) than the reinforcing bars vertically and horizontally arranged in the concrete, as shown in FIG. In this case, first, as shown in FIGS. 1A and 1B, each time high voltage pulse crushing is performed, the discharge electrode 13 is set at a deep position in the depth direction of the concrete, and a part of the main bar 30 is formed. Crush the concrete until it is exposed. Next, the position of the discharge electrode 13 is shifted so as not to be short-circuited by the nearby reinforcing bars 31, and the concrete around the distributing bars 31 is crushed so as to expose the distributing bars 31 located below the main bars 30 (same as above). (Refer figure (c)). Then, as shown in FIG. 4D, the completely exposed main muscle 30 and the distribution muscle 31 are cut and removed. This operation is continuously performed in the adjacent main muscle 30 and the distribution muscle 31 as well. Since the concrete area from which the reinforcing bars 30 and 31 are removed becomes an unreinforced state, the discharge electrode 13 is efficiently moved to a predetermined position of the concrete and installed, and the concrete is crushed until the suspended depth reaches the predetermined depth. (See (e) to (f) in the figure).

  As described above, when the concrete method of the present invention is applied to a reinforced concrete structure, if the discharge electrode 13 is disposed so as to avoid short circuit of high voltage pulses by the reinforcing bar and the concrete is crushed, the reinforcing bar is Even in the concrete that has been laid, the concrete that reaches the desired depth can be surely carried out.

The concrete of this invention is the partial cross section figure which showed the whole structure of the fishing device. The partial cross section figure which showed the example which applied the suspension apparatus to the concrete wall surface. The experimental result figure which showed the relationship between the distance L between terminals at the time of performing high voltage pulse crushing, and the water depth D. FIG. Explanatory drawing which showed the state of the reinforcement work of the reinforced concrete by a hanger. Explanatory drawing which showed the positional relationship between a suspended state and the reinforcement of the concrete by the movement of a discharge terminal. Explanatory drawing which showed the state of the reinforcement work of the reinforced concrete by a hanger. Explanatory drawing which showed the positional relationship between a suspended state and the reinforcement of the concrete by the movement of a discharge terminal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concrete surface 5 High voltage pulse generation device 7 Concrete wall surface 10 Hanging device 11 Cylindrical container 12 Insulating water (viscous water)
13 Discharge electrode 20 Seal member 30 Reinforcing bar (main reinforcing bar)
31 Reinforcement bars

Claims (4)

  A discharge electrode is erected at a distance L between electrodes in a cylindrical vessel placed on the concrete surface, and the cylindrical vessel is filled with insulating water so that the water depth is ½ × L or more. A concrete suspension method characterized in that a high voltage pulse applied to an electrode is propagated from the concrete surface to the inside, and the concrete surface between the discharge electrodes is suspended in a thin layer.   The concrete suspension method according to claim 1, wherein a sealing member is interposed between a lower edge of the cylindrical container and the concrete surface to prevent leakage of the insulating water.   The cylindrical container is set in a state in which the cylindrical container having a cylinder length of ½ × L or more with respect to the inter-electrode distance L of the discharge electrode installed inside is pressed against the concrete wall surface. A concrete suspension method characterized by filling a container with insulating water and propagating a high voltage pulse applied to the discharge electrode from the concrete surface to the inside to suspend the concrete wall surface between the discharge electrodes in a thin layer shape. .   The discharge electrode is placed on the concrete so that the inter-electrode distance L is equal to the bar spacing interval of the reinforcing bars arranged in the concrete, and the reinforcing bar is straddling the reinforcing-bar embedded part so that the reinforcing bar is located at the center of the inter-electrode distance L. 4. The concrete suspension method according to claim 1 or 3, wherein the concrete is suspended in a thin layer in order to abut against a surface or a wall surface.

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