JP2016196784A - PC grout filling investigation and sheath tube detection method during reinjection drilling, and PC grout filling investigation and reinjection hole drilling method - Google Patents

Abstract

A sheath tube detecting method and a sheath tube at the time of drilling for PC grout reinjection for detecting whether or not the drilled hole has reached the sheath tube without interrupting the drilling operation. There is provided a method for drilling a PC grout reinjection hole for drilling a PC grout reinjection hole in a PC structure without damaging the tendon inserted through the PC structure. When a hole for reinjecting a PC grout is drilled in a PC structure X, the PC grout reinjection for detecting whether or not the drilled hole has reached the outer surface of the sheath tube In the sheath tube detection method at the time of drilling for water, water is supplied to the hole drilled by the drilling machine 2 by the water supply / drainage device 4 through the water supply hose 41 while drilling the PC structure X by the drilling machine 2. When water is drained and sucked up together with dust generated by drilling through the drain hose 42 and metal is detected by the metal sensor 5 installed in the middle of the drain hose 42, the hole drilled is the outer surface of the sheath tube. It is determined that [Selection] Figure 1

Description

  The present invention provides a PC grout reinjection hole for drilling a hole for reinjecting PC grout into a PC structure for grout filling investigation and functional recovery of an existing prestressed concrete (hereinafter abbreviated as PC) structure. Drilling method, and hole for drilling a hole for re-injection of PC grout and a hole for microdestructive investigation of whether or not PC grout is filled reached the sheath tube The present invention relates to a sheath tube detection method at the time of drilling for PC grout reinjection for detecting whether or not.

  In PC structures in which concrete is prestressed with PC steel and other tendon materials, there is a risk of corrosion and fracture of PC steel in areas where PC grout is insufficiently filled. There is concern about the decline. In order to recover the function of such a PC structure, it is considered effective to reinject the PC grout into the insufficiently filled portion.

  In order to reinject the PC grout into the PC structure, it is necessary to drill a concrete portion of the PC structure and also make a hole in a sheath tube through which the PC steel material is inserted. Conventionally, the depth at which the sheath tube is embedded in the PC structure is estimated by an electromagnetic wave radar or the like and drilled, and whether or not the actually drilled hole has reached the sheath tube is determined visually. It was common to check with.

  For this reason, conventionally, in order to drill a hole for PC grout filling or for PC grout reinjection, after the drilled hole reaches the sheath tube, a space for opening the sheath tube with a tool such as a screwdriver. In addition, when a cavity is found, it is necessary to attach a pressure-resistant injection port (cap). Therefore, a hole having a diameter of about 60 mm to 100 mm is drilled using a diamond core bit or the like.

  However, since a strong bending stress is applied to the base end side like a cantilever beam, a large number of steel materials are over-packed in a PC structure constructed by overhanging construction in which steel bars are densely arranged. Therefore, since the degree of damage to the structure due to the drilling increases, it is necessary to reduce the drilling diameter.

  There is a method of drilling a PC structure with a wet small diameter core with metal sensor function, but when drilling with a wet small diameter core with metal sensor function, the degree of deterioration of the structure varies and differs depending on the construction site. , Metal sensor sensitivity adjustment is required. However, when the sensitivity is adjusted to high sensitivity, if water penetrates into the deteriorated part near the drilling hole tip, the sheath tube and drilling machine are electrically connected very shortly before the sheath tube, and a weak current is applied to the device. There is a problem of stopping. Conversely, if the sensitivity is adjusted to low sensitivity, it stops in contact with the sheath tube, but the sheath tube is 0.8mm thick, so there is a risk of piercing when drilling and damaging the internal PC steel There is a problem.

  Although there is a method of drilling with a small-diameter vibration rotary drill with a metal sensor, the rotary vibration drill with a metal sensor is dry, so there is no influence of malfunction due to permeated water on the deteriorated part. As a result, fine cracks are generated in the peripheral part of the drilling part, and there is a problem that the degree of damage to the structure is concerned.

  Further, there is a method of drilling with a water jet (WJ). However, when drilling with a water jet (WJ), there is a risk of clogging at the time of grout reinjection due to mixing of aggregate pieces in the sheath tube. In addition, the rust of the steel material is washed away at the same time, and it is difficult to observe the degree of deterioration of the steel material, and there are problems such as fixing the apparatus and wastewater treatment.

  Conventionally, the current value supplied to the motor of the drilling machine is measured, and when the measured current value becomes abnormally high, it is determined that the bit has come into contact with the reinforcing bar of the structure. . However, in the case of a sheath tube, since it is a steel plate of about 0.8 mm, there may be a case where a clear abnormal value does not appear as compared with the case of rebar contact, and the sheath tube when drilling a hole for PC grout reinjection. The current situation is that it is not used to detect this.

  On the other hand, as a method for drilling a PC grout reinjection hole for drilling a PC grout reinjection hole in a PC structure, Patent Document 1 discloses that the base 11 of the deep hole drilling machine 100 is fixed to the work surface 10. A first step S1 to perform, a second step S2 to rotatably support a shaft of a drilling tool attached to a tool rotation drive mechanism that moves along a strut of a deep hole drilling machine at a position near the work surface, and cooling water The third step S3 for supplying the drilling tool to the tip side of the drilling tool, and when forming a deep hole with the drilling tool, a pool of cooling water and suspended water of concrete grinding is surrounded by a hole around the work surface. And a fourth step S4 for sucking and discharging the waste water, and a fifth step S5 for forming a deep hole corresponding to the length of the shaft by filtering and circulating the discharged suspension water so as to be supplied as the cooling water. A deep hole forming method performed in a procedure is disclosed ( Claim 1 of the claims of Patent Document 1, description of paragraphs [0032] - [0049], see FIG. 2 to FIG. 7 of the drawings).

  According to the deep hole forming method described in Patent Document 1, it is possible to form a deep hole in a PC structure without being shaken in the drilling operation even if the shaft is thin, and to supply and suspend cooling water. It is said that a deep hole can be formed in a state in which concrete dust is not clogged by suction of muddy water.

  However, in the deep hole forming method described in Patent Document 1, although the concrete portion of the PC structure can be drilled, when the sheath tube is opened as it is, a tension material such as a PC steel material inserted into the sheath tube is used. There is a possibility of damage, and a method for determining whether or not a hole has been drilled to the vicinity of the outer surface of the sheath tube has been desired.

JP 2009-160780 A

  Therefore, the present invention has been devised in view of the above-mentioned problems, and the object of the present invention is to simplify and cut the hole when a PC grout reinjection hole is drilled in an existing PC structure. A method for detecting a sheath tube during drilling for PC grout reinjection, which detects whether or not the hole being drilled has reached the sheath tube without interrupting the drilling operation, and tension inserted through the sheath tube An object of the present invention is to provide a method for drilling a PC grout reinjection hole in which a PC grout reinjection hole is drilled in a PC structure without damaging the material.

  The sheath tube detection method during drilling for PC grout reinjection according to the first aspect of the present invention is performed when drilling a hole for reinjecting PC grout into the sheath tube of an existing PC structure in the PC structure. A method for detecting a sheath tube at the time of drilling a hole for PC grout reinjection for detecting whether or not the hole being drilled has reached the outer surface of the sheath tube, wherein the PC structure is drilled by a drilling machine. While supplying water to the hole drilled by the drilling machine through the water supply hose through the water supply / drainage device, sucking up the water supplied together with the dust generated by the drilling through the drainage hose, When the metal is detected by the metal sensor installed in the tube, it is determined that the drilled hole has reached the outer surface of the sheath tube.

  The sheath tube detection method at the time of drilling for PC grout reinjection according to the second invention is the first invention, wherein the energization amount at the time of drilling is not less than a predetermined amount by an ammeter that measures the energization amount to the drilling machine. Even when the abnormal value is measured, it is determined that the drilled hole has reached the outer surface of the sheath tube.

  According to a third aspect of the present invention, there is provided a method for drilling a PC grout reinjection hole in which a hole for reinjecting PC grout into a sheath pipe of an existing PC structure is drilled in the PC structure. A hole drilling method in which water is supplied to a hole drilled by the drilling machine via a water supply hose by a water supply / drainage device while the PC structure is drilled by a drilling machine, and the hole is cut through the drainage hose. When the water supplied together with the dust generated by the holes is sucked up and metal is detected by a metal sensor installed in the middle of the drainage hose, the drilling machine is energized by the control unit that controls the energization of the drilling machine. It is characterized by stopping.

  According to a fourth aspect of the present invention, there is provided a method for drilling a PC grout reinjection hole according to the third aspect, wherein an abnormal value higher than a predetermined amount by a current meter for measuring the amount of current supplied to the drilling machine is measured by an ammeter for measuring the amount of current supplied to the drilling machine. In this case, the power supply to the drilling machine is stopped by the control unit that controls the power supply to the drilling machine.

  According to the first invention, the metal sensor installed in the middle of the drainage hose can detect metals such as iron powder passing through the drainage hose, so the hole drilled by the drilling machine reaches the sheath tube. Thus, it is possible to reliably detect that the sheath tube has been shaved.

  In particular, according to the second invention, even when an abnormal value is measured by an ammeter, it is determined that the hole drilled by the drilling machine has reached the outer surface of the sheath tube. This makes it possible to detect that the hole drilled by the drilling machine reaches the sheath tube more accurately.

  According to the third invention, when the metal is detected by a metal sensor installed in the middle of the drainage hose, the control unit for controlling the energization to the drilling machine stops the energization to the drilling machine. It can be seen that the drilling hole has reached the sheath tube without providing a notification means for notifying the detection by the sensor. Moreover, since the drilling machine can be stopped at the same time when the drilling hole reaches the sheath tube, there is no possibility of damaging the tension material inserted into the sheath tube.

  In particular, according to the fourth aspect of the present invention, the drilling machine can be reliably stopped at the same time as the drilled hole reaches the sheath tube by the double check using the metal sensor and the ammeter.

It is a side view showing the whole drilling device composition used for the drilling method of the hole for PC grout reinjection concerning the embodiment of the present invention. It is a perspective view which shows the positioning plate vicinity of the drilling machine of a hole drilling device same as the above. It is a partial expansion perspective view which shows a positioning plate same as the above. It is explanatory drawing which shows the procedure of the drilling method of the hole for a PC grout reinjection which concerns on embodiment of this invention.

  Hereinafter, an embodiment for carrying out a method for detecting a sheath tube during drilling for PC grout reinjection and a method for drilling a hole for PC grout reinjection according to the present invention will be described in detail with reference to the drawings. .

<Drilling device>
First, with reference to FIG. 1 to FIG. 3, a sheath tube detection method at the time of drilling a PC grout reinjection according to an embodiment of the present invention and a hole drilling device used for a hole drilling method of a PC grout reinjection hole will be described. To do. A drilling device for drilling a PC structure X is used for a sheath tube detection method and a PC grout reinjection hole drilling method when drilling a PC grout reinjection hole according to an embodiment of the present invention. 2, a guide device 3 for slidably guiding the drilling machine 2, a water supply / drainage device 4 for supplying water to the drilled hole and sucking up the dust generated by the drilling and the supplied water, and a drainage hose 42 to be described later A metal sensor 5 that detects the metal passing through the inside, an ammeter 7 that measures the amount of current flowing from the AC power source 6 to the drilling machine 2, and the metal sensor 5 and the ammeter 7 that are electrically connected to the drilling machine 2 It is comprised from the control apparatus 8 etc. which control electricity supply.

(Punching machine)
As shown in FIG. 1, the punching machine 2 has a normal electric motor 20 having a rotational speed of about 8000 / min to 8500 / min as a drive motor. The electric motor 20 rotates a shaft 21 to rotate the shaft 21. This is a device for drilling a PC structure X with a drill bit 22 attached to the tip. In addition, it is also possible to use a vibration drill that applies not only rotation but also striking along the axial direction by a ratchet mechanism.

  The shaft 21 is prepared in various lengths depending on the depth of the hole to be drilled, and has a structure in which a plurality of shafts 21 can be appropriately added by screwing. For this reason, according to the punching machine 2, a deep hole of 5 m or more can be drilled.

  Further, the drill bit 22 according to the present embodiment employs a short round bar-shaped non-core bit having a diameter of about 15.5 mm to 25 mm. The drill bit 22 is made of an alloy containing a large number of artificial diamonds. But there is. For this reason, a small-diameter hole having a diameter of 30 mm or less can also be drilled in the high-strength PC structure X.

  However, the drill bit according to the present invention can adopt a conventional diamond core bit, and includes a large number of cemented carbide chips as long as the PC structure X can be drilled. Other drilling bits such as a drag bit may be employed.

(Guide device)
The guide device 3 is configured to be placed or adsorbed on the PC structure X, a support 31 standing on the support 30, and slidably movable along the support 31. The guide member 32 to be mounted and the positioning plate 33 that is attached to the side of the base 30 and positions the shaft 21 and the drill bit 22 of the drilling machine 2 and guides the rotation of the drilling machine 2 so as not to shake. have.

  The base 30 is bolted to the PC structure X with anchor bolts or connected to a vacuum pump (P1) (not shown), and the inside of the base 30 is set to a pressure lower than atmospheric pressure (vacuum) to form a PC structure. It is fixed to the object X. For this reason, the guide device 3 can be fixed to both the horizontal plane and the vertical plane of the PC structure X.

  The support column 31 is provided substantially vertically with respect to the base 30, and a rack (not shown) that meshes with a pinion gear described later is formed on one side surface. Moreover, the support | pillar 31 is good also as a structure which can adjust angle with respect to the base 30 by the structure of a volt | bolt and a circular arc-shaped long hole. This is because by making the column 31 adjustable with respect to the base 30, the drilling machine 2 can be guided while being inclined with respect to the work surface of the PC structure X.

  The guide member 32 has a pinion gear (not shown) that is rotated by a handle 32 a at a position facing the rack of the support column 31, and the pinion gear is rotated by turning the handle 32 a, and this pinion gear is rotated by the rack of the support column 31. Is configured to move up and down (slide movement) along the column 31.

  Further, the guide member 32 includes a mounting portion 32b for mounting the drilling machine 2, and a water supply hose 41 of a water supply / drainage device 4 to be described later is connected to the mounting portion 32b and drilled through the shaft 21 of the drilling machine 2 A water supply chamber (not shown) for supplying cooling water to the holes is provided.

  As shown in FIGS. 2 and 3, the positioning plate 33 is positioned near the center of the plate body 33a so as to insert the shaft 21 of the drilling machine 2 to position the drilling position and prevent rolling during rotation. 33b is attached. The positioning member 33b is swingably attached to the plate body 33a. Even when the pillar 31 is inclined with respect to the base 30 to drill holes, the shaft 21 is positioned at a predetermined position and rotated. Can be prevented from rolling.

  Further, the plate body 33a has a cavity (not shown) formed on the lower surface, and a plurality of drainage hoses 42 of a water supply / drainage device 4 to be described later are connected from the side to contact the PC structure X. The system is designed to suck up and suck up the water supplied to the hole drilled at low pressure (vacuum).

(Water supply / drainage system)
As shown in FIGS. 1 to 3, the water supply / drainage device 4 includes a device main body 40 having a pump (not shown) that feeds cooling water into the interior and sucks the drainage, and a water supply chamber of the device main body 40 and the mounting portion 32b. A plurality of drainage hoses for communicating drainage from the positioning plate 33 to the apparatus main body 40. The water supply hose 41 for sending cooling water from the apparatus main body 40 to the water supply chamber, the apparatus main body 40 and the positioning plate 33 for communication 42 and the like.

  This water supply / drainage device 4 supplies cooling water to the holes drilled by the drilling machine 2 through a water supply hose 41 by a pump of the device main body 40, and cuts through a plurality of drainage hoses 42 by a pump of the device main body 40. It has a function of sucking up water supplied together with dust generated by the holes as drainage.

(Metal sensor)
The metal sensor 5 is a non-contact transmission type metal sensor that is disposed so as to surround the drainage hose 42 in the middle of any drainage hose 42 and detects that the drainage flowing through the drainage hose 42 contains metal. is there.

  The metal sensor 5 may be a commercially available metal sensor as long as it is a non-contact transmission type metal sensor. For example, an inductive proximity sensor is suitable. The mechanism of this inductive proximity sensor is as follows. When a metal object approaches the high-frequency magnetic field generated by the detection coil connected to the oscillation circuit, an induced current due to an electromagnetic induction phenomenon flows in the adjacent metal, and heat loss occurs in the metal. Then, the oscillation circuit cannot maintain the oscillation, and the oscillation of the oscillation circuit is attenuated or stopped. A circuit for detecting the oscillation state of the oscillation circuit is separately provided, and this circuit detects the metal approaching the sensor by detecting the attenuation of the transmission circuit.

  Further, since the sheath tube is generally made of tinplate or galvanized steel sheet, the metal sensor 5 may not be a metal sensor that can detect metals in general but may be one that can detect only iron (iron powder).

(Ammeter)
The ammeter 7 is a general commercially available ammeter that is provided in the middle of a current path from the AC power supply 6 that is a commercial power supply to the electric motor 20 of the punching machine 2 and measures the amount of current supplied to the electric motor 20.

(Control device)
The control device 8 is electrically connected to the metal sensor 5 and the ammeter 7 and is a control device that controls energization to the electric motor 20 of the drilling machine 2. Specifically, when it is detected by the metal sensor 5 that the metal has passed, the control device 8 controls to stop energization of the electric motor 20, and the energization amount measured by the ammeter 7 is equal to or greater than a predetermined amount. When it becomes, it controls to stop electricity supply to the electric motor 20.

  This predetermined amount is difficult to specify because the amount of current applied to the electric motor 20 at the time of drilling differs depending on the strength of the PC structure and the type of coarse aggregate, but it is difficult to specify specifically, but the concrete portion of the PC structure X is ground. It is an abnormal energization amount that exceeds the energization amount of the normal state that is perforated (for example, more than double the energization amount of the normal state). Since the amount of energization when drilling a general strength concrete is about 3 to 5 amperes, in that case, the control device 8 is set so that the energization is stopped at 6 to 10 amperes. In this way, the predetermined amount for stopping energization by the control device 8 is set by fine adjustment on site in accordance with the strength of the PC structure and the type of coarse aggregate, and taking into account the energization amount at the time of drilling. Is done.

<Sheath tube detection method during drilling for PC grout reinjection>
Next, a sheath tube detection method during drilling for PC grout reinjection according to an embodiment of the present invention will be described using the above-described drilling device 1.

  When the hole for reinjecting the PC grout into the sheath tube of the existing PC structure X is drilled by the hole drilling device 1 described above, the electric motor 20 is driven and the PC structure X is moved by the drilling machine 2. While drilling, the water supply / drainage device 4 supplies water to the hole drilled by the drilling machine 2 via the water supply hose 41, sucks up the turbid water mixed with the dust generated by the drilling via the drainage hose 42 and drains it. doing.

  Moreover, the metal sensor 5 installed in the middle of the drainage hose 42 continuously detects whether or not metal is contained in the turbid water flowing in the drainage hose 42.

  On the other hand, when the hole drilled by the hole drilling device 1 reaches the outer surface of the sheath tube, the drill bit 22 of the drilling machine 2 comes into contact with the sheath tube and is cut by the drill bit 22 to be sheath tube. The metal metal powder (iron powder) that constitutes the water is generated, and flows into the vicinity of the metal sensor 5 through the drainage hose 42 as turbid water together with the concrete shaving powder.

  For this reason, it is possible to reliably detect that the hole drilled by the drilling machine 2 has reached the sheath tube and the sheath tube has been scraped. As a result, the drilled hole is outside the sheath tube. Whether the surface has been reached can be detected.

  Further, in the hole drilling device 1, separately from the metal sensor 5, an energization amount to the electric motor 20 is measured and monitored by an ammeter 7.

  For this reason, when the drill bit 22 comes into contact with something other than concrete and the amount of current supplied to the electric motor 20 shows an abnormal value, the hole drilled by the hole drilling device 1 becomes the outer surface of the sheath tube. Can be inferred.

  Conventionally, detection of foreign object contact by such an ammeter has been used as detection of whether or not the drill bit 22 has come into contact with foreign objects such as reinforcing bars. However, the sheath tube is as thin as about 0.8 mm, and there may be cases where a clear abnormal value does not appear and detection may be missed, so it should be applied to detect whether the drilled hole has reached the outer surface of the sheath tube. It was difficult.

  However, by performing a double check with the metal sensor 5, the detection accuracy is greatly improved, and it can also be applied to detect whether or not the drilled hole has reached the outer surface of the sheath tube.

  According to the sheath tube detection method at the time of drilling holes for PC grout reinjection according to the embodiment of the present invention described above, iron powder passing through the drain hose 42 by the metal sensor 5 installed in the middle of the drain hose 42, etc. Therefore, it is possible to reliably detect that the hole drilled by the punching machine 2 reaches the sheath tube and the sheath tube is scraped.

  In addition, according to the sheath tube detection method during drilling for PC grout reinjection according to the embodiment, even when an abnormal value is measured by the ammeter 7, the hole drilled by the drilling machine 2 is not the sheath tube. Since it is determined that the outer surface has been reached, a double check between the so-called metal sensor 5 and the ammeter 7 is performed, and it can be detected more accurately that the hole drilled by the drilling machine 2 reaches the sheath tube. .

<Drilling method of PC grout reinjection hole>
Next, with reference to FIG. 4, a method for drilling a PC grout reinjection hole according to an embodiment of the present invention will be described in the case of drilling using the above-described drilling apparatus 1.

(1) Strut Positioning In the method for drilling holes for PC grout reinjection according to the embodiment, as shown in FIG. 4, first, according to the (inking out) position of the hole to be drilled, the guide device 3 has a PC structure. In order to fix it on the surface of the object X, the vacuum pad P1 is sucked by the vacuum pump P1 to make the inside of the vacuum pad P2 negative pressure and adsorbed on the surface of the PC structure X.

(2) Fixing of guide device Next, the above-mentioned base 30 is inserted into the fixing bolt of the vacuum pad P2 and screwed, and the guide device 3 is fixed so that the column 31 is perpendicular to the surface of the PC structure X. To do.

  If the vacuum pad P2 cannot be adsorbed because the surface of the PC structure X is deteriorated, an anchor such as a hole-in anchor or a chemical anchor is driven into the PC structure X, and the base 30 The (guide device 3) may be fixed with screws.

(3) Adjustment of the drilling position Then, the drilling machine 2 is mounted on the mounting portion 32b of the guide member 32 so that the drilling machine 2 is located immediately above the mark (inking position) of the center of the hole to be drilled. adjust.

(4) Setting of positioning plate and water supply / drainage device Next, the positioning plate 33 is set on the side of the base 30 of the guide device 3, and the shaft 21 of the drilling machine 2 is perpendicular to the surface of the PC structure X. Make further fine adjustments.

  At this time, the water supply hose 41 is connected to the mounting portion 32 b of the guide member 32, the drainage hose 42 is connected to the positioning plate 33, and the water supply hose 41 and the drainage hose 42 are connected to the apparatus main body 40 of the water supply / drainage device 4. Then, the water supply / drainage device 4 is set so as to be able to supply and drain water.

(5) Start of drilling Then, the drill bit 22 is mounted on the tip of the shaft 21 of the drilling machine 2, the electric motor 20 of the drilling machine 2, and the pump in the device main body 40 of the water supply / drainage device 4 are operated, and the PC Drilling of holes for PC grout reinjection into the structure X is started.

  At this time, cooling water is supplied to the hole drilled by the water supply / drainage device 4 via the water supply hose 41 while drilling with the drilling machine 2, and supplied with the dust generated by the drilling via the multiple drainage hoses 42. Suction the collected water as drainage.

(6) Shaft extension Next, while driving the electric motor 20 to drill the PC structure X with the drilling machine 2, the handle 32a of the guide member 32 is appropriately rotated to lower the drilling machine 2 (PC structure). Move to the object X side) and drill a hole for grout injection in the PC structure X.

  At this time, the shaft 21 made of a rod having a length of about 200 mm (round bar-shaped steel material) is extended one after another and drilled until reaching a desired depth, that is, the outer surface of the sheath tube. .

(7) Judgment whether or not the sheath tube has been reached Judgment whether or not the hole drilled by the punching machine 2 has reached the outer surface of the source tube is the PC grout reinjection hole according to the above-described embodiment. The sheath tube detection method is used when drilling. Specifically, the metal sensor 5 detects that the metal powder is contained in the drainage flowing through the drainage hose 42, and the control device 8 uses the information from the electrically connected metal sensor 5 to control the punching machine 2. The energization of the electric motor 20 is stopped.

  In addition, the amount of current supplied to the electric motor 20 is transmitted to the control device 8 as a measured value from the ammeter 7, and when this measured value is equal to or greater than the predetermined amount, the control device 8 determines that the abnormal value And the energization to the electric motor 20 of the punching machine 2 is stopped.

  In short, the control device 8 stops energization of the electric motor 20 when the metal sensor 5 detects metal or when the measured value of the ammeter 7 becomes a predetermined amount or more.

  As described above, the energization is stopped in any of the cases described above, and the drilling is immediately stopped, so that there is no possibility of damaging the tendon inserted in the sheath tube.

  However, if the detection accuracy of the ammeter 7 is poor, a configuration in which energization to the electric motor 20 is not stopped unless the metal sensor 5 detects metal is also possible. However, from the viewpoint that the tendon is never damaged, a configuration in which energization is stopped in either case as in the present embodiment is preferable.

  As a result, the drilling operation of the PC grout reinjection hole is completed, and thereafter, a post-process for PC grout reinjection, such as a sheath tube opening step of opening a PC grout reinjection hole in the sheath tube, is performed.

  According to the drilling method of the PC grout reinjection hole according to the present embodiment described above, the drilling machine 2 can be stopped simultaneously with the drilling of the drilling machine 2 reaching the sheath pipe. There is no risk of damaging the inserted tendon. Further, the double check by the metal sensor 5 and the ammeter 7 can surely stop the drilling machine 2 at the same time when the drilling hole reaches the sheath tube, and further eliminates the possibility of damaging the tendon.

  As mentioned above, the sheath tube detection method at the time of drilling for PC grout reinjection according to the embodiment of the present invention, the hole drilling method of the hole for PC grout reinjection according to the embodiment of the present invention, and the hole drilling device used in the method However, the above-described or illustrated embodiment is merely a specific embodiment for carrying out the present invention, which limits the technical scope of the present invention. It should not be interpreted. In particular, the material of the drill bit may be appropriately selected according to the strength of the PC structure and the type of the sheath tube. Moreover, although the motor which drives a drilling machine illustrated the electric thing, as long as it can rotate a shaft other than an engine, it can apply.

1: Drilling device 2: Drilling machine 20: Electric motor (drive motor)
21: Shaft 22: Drill bit 3: Guide device 30: Base 31: Post 32: Guide member 32a: Handle 32b: Mounting portion 33: Positioning plate 33a: Plate body 33b: Positioning member P1: Vacuum pump P2: Vacuum pad 4 : Water supply / drainage device 40: Device main body 41: Water supply hose 42: Drainage hose 5: Metal sensor 6: AC power supply (commercial power supply)
7: Ammeter 8: Control device X: PC structure

Claims (4)

When drilling holes in the PC structure for reinjecting PC grout into the sheath pipe of an existing PC structure, it is detected whether the drilled hole has reached the outer surface of the sheath pipe. A sheath tube detection method during drilling for PC grout reinjection,
While drilling the PC structure with a drilling machine, water is supplied to the hole drilled by the drilling machine through the water supply hose with the water supply / drainage device and supplied with the dust generated by the drilling through the drainage hose. The PC grout is characterized in that when the water is sucked up and metal is detected by a metal sensor installed in the middle of the drain hose, it is determined that the drilled hole has reached the outer surface of the sheath tube. Sheath tube detection method when drilling holes for reinjection. The hole that has been drilled has reached the outer surface of the sheath tube even when an abnormal value in which the energization amount during drilling has exceeded a predetermined amount is measured by an ammeter that measures the energization amount to the drilling machine. The sheath tube detection method at the time of drilling holes for PC grout reinjection according to claim 1, characterized in that: A method for drilling a PC grout reinjection hole for drilling a hole in a PC structure for reinjecting PC grout into a sheath tube of an existing PC structure,
While drilling the PC structure with a drilling machine, water is supplied to the hole drilled by the drilling machine through the water supply hose with the water supply / drainage device and supplied with the dust generated by the drilling through the drainage hose. When the metal is detected by a metal sensor installed in the middle of the drainage hose, the energization to the drilling machine is stopped by a control unit that controls the energization to the drilling machine. Drilling method for PC grout reinjection holes. When an abnormal value higher than the energization amount at the time of drilling is measured by an ammeter that measures the energization amount to the drilling machine, the energization to the drilling machine is performed by a control unit that controls energization to the drilling machine. The method for drilling holes for PC grout reinjection according to claim 3, wherein:

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