JP2014105527A - Method of refilling grout into grout-unfilled cavity in sheath of existing pc structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method allowing grout to be more completely refilled into a grout-unfilled cavity in a PC tendon insertion sheath in an existing PC structure without leaving a dead air space.SOLUTION: When forming a grout pressure injection port 13 and an exhaust port 14 in a grout-unfilled cavity 12 in a PC tendon insertion sheath 11 in an existing PC structure 10 and pressure-injecting the grout from the grout pressure injection port 13 by a grout pressure injection device 20, a miniature camera 32 is provided at a tip of an insertion part 31, an actuator gateway is formed inside the insertion part 31, the tip of the insertion part 31 is inserted from the exhaust port 14 by using an endoscope 30 having a front end surface where the tip of the actuator gateway is opened while monitoring the inside of the grout-unfilled cavity 12 through the miniature camera 32, and the grout is pressure-injected from the grout injection port while exhausting air through the actuator gateway of the endoscope 30.

Description

  The present invention provides a sheath inside an existing PC structure that enables more complete grout filling when a grout unfilled cavity in a sheath for inserting a PC tendon in an existing post-tension type PC structure is refilled. The present invention relates to a method for refilling grout into an unfilled cavity.

  In general, a post-tension type PC structure introduces pre-stress by inserting a PC tension material into a PC tension material insertion sheath installed in the structure and tensioning the PC tension material after the concrete of the structure is hardened. In this way, the grout is filled in the gap in the sheath for inserting the PC tendon after introduction of the prestress.

  In recent years, early deterioration such as cracking, peeling and reinforcing steel corrosion has become a serious problem in concrete structures, and it is no exception in PC structures that do not cause cracking by applying prestress. A particular problem with PC structures is the corrosion of PC steel, the main cause of which is PC grout failure, and deterioration damage due to the quality of the initial PC grout material and poor grout filling during construction. Corrosion and breakage of PC steel occurred. This became apparent from the late 1980s to the 1990s. However, it has reached today with insufficient measures.

  On the other hand, recent advances in non-destructive inspection methods have made it easier to inspect grout-filled areas and refill the grout-unfilled cavities. A method of refilling the grout to the part has been developed. Mainly, there are a press-fitting method (for example, Non-Patent Document 1) and a vacuum grout method using a vacuum pump (for example, Non-Patent Document 2 and Patent Document 1).

  The press-fitting method estimates grout unfilled locations, drills holes at two locations on both ends of the section, confirms ventilation between the drilled holes, and then injects one hole and discharges the other. As a method of performing pressure injection of grout.

  In the vacuum grouting method, a discharge port and a grouting pressurization injection port are formed in a grout unfilled cavity, and the inside of the sheath for inserting the PC tendon is reduced by a vacuum pump from the discharge port. The grout is press-fitted by a pressure feed pump, and the injection is stopped after the grout is discharged from the discharge port.

PC grout reinfusion repair manual (draft) Railway Technical Research Institute Kawada Technical Report Vol. 23 2004 Pages 56-61 Repair and reinforcement work for road bridge PC girders

JP 2005-23567 A

  In the conventional refilling method described above, refilling can be more complete as the discharge port is closer to the top end of the grout unfilled cavity. The boundary between the unfilled grouting cavity and the filled portion in the sheath for inserting the PC tendon material cannot be accurately known, and therefore, there is a problem that the unfilled cavity remains at the upper end portion that is located above the discharge port. is there.

  In view of the above-described conventional problems, the present invention is an existing PC structure that can be completely refilled without leaving an air pocket in a grout unfilled cavity in a sheath for inserting a PC tendon in an existing PC structure. It was made for the purpose of providing a method for refilling grout into a cable sheath of an object.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a grout unfilled cavity in a sheath for inserting a PC tension material in an existing post-tension type PC structure is grouted. An existing PC that forms a grout pressure injection port for injecting air and a discharge port for discharging air in the unfilled cavity of the grout and pressurizes and injects grout from the grout pressure injection port by a grout pressure injection device In a method for refilling a grout in a sheath without filling grout in a sheath of a structure, a small camera is provided at the distal end of the insertion portion, and an operation device entry / exit passage is formed inside the insertion portion, and the distal end of the operation device entry / exit passage Using an endoscope opened at the end face of the insertion portion, and monitoring the inside of the grout unfilled cavity through the small camera while the front end of the insertion portion of the endoscope is Inserting into the upper end side of the grout unfilled cavity from the outlet, and pressurizing and injecting the grout from the grout inlet by the grout pressure injection device while exhausting through the operation / outlet opening of the endoscope. .

  The feature of the invention of claim 2 is that, in addition to the configuration of claim 1, the insertion portion of the endoscope is inserted into the upper end side of the unfilled cavity of the grout and is discharged from the operation device insertion / removal port at the distal end of the insertion portion. A cylinder is inserted toward the upper end of the grout unfilled cavity, and the grout is pressurized and injected from the grout injection port by a grout pressure injection device while exhausting through the exhaust tube.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, in a state where the exhaust pipe is inserted toward the upper end of the grout unfilled cavity, The gap is hermetically sealed, the side end of the exhaust pipe not filled with grout is decompressed by a vacuum pump, and the grout filled up to the upper end of the grout unfilled cavity is sucked out through the exhaust pipe, thereby re-establishing the grout. The purpose is to check the filling state.

  According to the present invention, a compact camera is provided at the distal end of the insertion portion as described in claim 1, and an operation device entry / exit passage is formed inside the insertion portion, and the distal end of the operation device entry / exit passage is the insertion portion. An endoscope opened on the end face of the endoscope is used, and the inside of the unfilled cavity is monitored through the small camera, and the distal end of the insertion portion of the endoscope is moved from the discharge port to the upper end side of the unfilled cavity. The state of the upper end portion of the unfilled cavity is determined by inserting and injecting grout from the grout injection port by a grout pressure injection device while exhausting through the insertion / extraction port of the endoscope. The grout can be re-injected while monitoring, and the air in the unfilled cavity at the time of re-injection is exhausted through the entrance / exit of the operation device of the endoscope. It is possible to grout re-filling without leaving.

  According to the present invention, as shown in claim 2, the insertion portion of the endoscope is inserted into the upper end side of the unfilled cavity of the grout, and the exhaust tube is inserted into the unfilled grout from the operation unit outlet at the distal end of the insertion portion. By inserting it toward the upper end of the cavity and pressurizing and injecting grout from the grout injection port by the grout pressure injection device while exhausting through the exhaust pipe, the upper end of the unfilled cavity is narrowed. Even when the distal end of the insertion part of the endoscope cannot be inserted up to the upper end of the unfilled cavity, it is possible to use a small-diameter exhaust pipe and to insert the distal end of the exhaust pipe up to the upper end of the unfilled cavity. Grout refilling is possible without leaving

  In the present invention, the exhaust tube is inserted toward the upper end of the grout-unfilled cavity, and the gap between the exhaust tube and the operation unit inlet / outlet is hermetically sealed, and the grout-unfilled cavity of the exhaust tube is provided. The side end is depressurized by a vacuum pump, and the grout filled up to the upper end of the grout unfilled cavity is sucked through the exhaust pipe to confirm the refill state of the grout. Even when the grout re-injection state at the upper end of the unfilled grout cavity cannot be grasped by the camera, it is possible to confirm that the grout leakage from the exhaust pipe has reached the uppermost end of the unfilled grout cavity.

It is a longitudinal cross-sectional view which shows the outline of the 1st Example of this invention method. It is a front view of an insertion part tip of an example of an endoscope used in the present invention. It is a longitudinal cross-sectional view which shows the outline of the 2nd Example of this invention method. It is a partial fragmentary expanded sectional view which shows the exhaust pipe insertion state to the upper end part of the grout unfilled cavity same as the above.

  Embodiments of the present invention will be described with reference to the drawings of the embodiments.

First, the grout unfilled cavity in the sheath for inserting the PC tendon material in the existing PC structure is searched. As the exploration method, an X-ray transmission method in which the grout filling state is inspected using a high-power X-ray generator, an electromagnetic wave radar method in which electromagnetic waves are radiated from the concrete surface into the interior, reflected waves from the object are received, and image processing is performed. , Broadband ultrasonic method that transmits broadband (2.5-1000kHz) ultrasonic waves at once, measuring elastic waves reflected by vibrations due to shocks to voids, reinforcing bars, etc., and determining internal defects by the strength of the waveform For example, a shock elastic wave method, a magnetic exploration method for supplying a magnetic field from a magnet to a PC steel material, and detecting a magnetic change occurring at a fractured portion can be used.
The grout unfilled cavities are identified by the above-described exploration method, and the surface of the PC structure corresponding to the positions assumed as both ends thereof is marked.

  Next, as shown in FIG. 1, the grout pressure inlet 13 leading to the grout unfilled cavity 12 in the PC tendon insertion sheath 11 and the air in the unfilled portion 12 are discharged from the surface of the PC structure 10. The discharge port 14 is formed by drilling. In the figure, symbol a is an existing grout and b is a PC tendon.

  As shown in FIG. 1, this drilling hole forms a grout pressure injection port 13 near the lower end of the grout unfilled cavity 12 and forms a discharge port 14 on the side surface near the upper end. In the drawing, the opening is made on the upper surface of the PC structure 10, but it may be a side surface.

  As a drilling method, there are a core drill method and a water jet method. Core drills are at risk of steel damage. Therefore, a water jet drilling method is desirable.

  After forming the grout pressurizing inlet 13 and the outlet 14 in this way, the ventilation is confirmed and the inside of the grout unfilled cavity 12 is observed with a fiberscope or an endoscope 30 to be described later. Whether the steel wire is sound, whether the steel wire is healthy, is rust generated, or is broken? If water is contained, the lowest position is drilled to drain water, and if it is difficult to drain water, dry air is sent from the grout pressure inlet to remove moisture in the sheath.

Next, a grout injection hose 15 is attached to the grout pressure injection port 13. A Tetron blade hose can be used as this hose. In addition, the gap between the grouting pressure inlet 13 and the grouting hose 15 is sealed with a putty or the like.
The grout injection hose 15 communicates with the grout pressurization injection device 20 through an on-off valve 21.

  The insertion portion 31 of the endoscope 30 is inserted from the discharge port 14. The endoscope 30 includes a small camera 32 (shown in FIGS. 2 and 4) at the distal end of a cylindrical insertion portion 31, photographs the insertion portion distal end extension side, and displays the image on the monitor 33. I try to let them.

  An illumination light 34 is provided on the end surface of the insertion portion 31, and an operating unit access path is formed between the distal end surface and the operation portion 35. The distal end opening 36 is an end surface of the insertion portion 31. And an opening / closing port 37 for the operating tool is used in the insertion portion connecting portion of the operation portion 35.

  The insertion portion 31 of the endoscope 30 is inserted into the discharge port 14 and is inserted toward the upper end portion side of the grout unfilled cavity 12 while monitoring the front side thereof with the small camera 32.

  At this time, as shown in FIG. 1, when the insertion is possible to the extent that it is in contact with the upper end portion of the grout unfilled cavity 12 or to the immediate vicinity thereof, it is inserted between the insertion portion 31 and the discharge port 14 until the depth is reached. Seal the gap. For this sealing, a putty similar to the gap between the grout pressure inlet 13 and the grout hose 15 described above can be used.

  The vacuum suction hose 16 is connected to an operating unit insertion / extraction port 37 opened in the operation unit 35 of the endoscope 30, and the vacuum pressure resistant container 25 is communicated with the vacuum suction hose 16 via the opening / closing valve 26. The vacuum pump 27 is communicated with 25.

  After mounting the grout injection hose 15, the grout pressure injection device 20, the endoscope 30 and the vacuum pump 27 in this way, the grout pressure injection device 20 passes through the grout injection hose 15 and the lower end side of the unfilled cavity 12. Press fit grout more. At the same time, the vacuum pump 27 decompresses the upper end side of the unfilled cavity 12 through the vacuuming hose 16 and reinjects the grout into the unfilled cavity 12.

  At this time, the upper end of the grout unfilled cavity is monitored by the small camera 32 of the endoscope, and the grout is blocked by the grout, and the grout leaks out from the vacuum hose 16 to the vacuum-resistant vessel 25. Injection up to the upper end of the unfilled cavity can be confirmed.

  On the other hand, when the insertion portion 31 of the endoscope 30 cannot be inserted to the vicinity of the upper end portion of the grout unfilled cavity 12, the insertion portion 31 is inserted into the upper end side of the grout unfilled cavity, as shown in FIG. In a state where the gap between the surroundings and the discharge port 14 is sealed, the exhaust tube 40 having a thickness capable of sucking out grout is inserted from the operation device insertion / removal port 37 of the endoscope 30, and the tip thereof is inserted into the insertion portion 31. It is fed out from the tip of the tube until it reaches a position close to the upper end of the grout unfilled cavity 12.

  In this state, the gap between the exhaust tube 40 and the operation unit insertion / removal port 37 is hermetically sealed by packing (not shown), and the end of the exhaust tube 40 is connected to the vacuum suction hose 16, which is described above. Similarly, the vacuum pressure resistant container 25 is communicated with the open / close valve 26, and the vacuum pump 27 is communicated with the vacuum resistant container 25.

  After mounting the grout injection hose 15, the grout pressure injection device 20, the endoscope 30 and the vacuum pump 27 in this way, the grout pressure injection device 20 passes through the grout injection hose 15 and the lower end side of the unfilled cavity 12. Press fit grout more. At the same time, the vacuum pump 27 depressurizes the upper end side of the grout unfilled cavity 12 through the vacuum hose 16 and the exhaust pipe 40, and reinjects the grout into the grout unfilled cavity 12.

  At this time, when the injected grout reaches the distal end of the insertion portion of the endoscope 30, the field of view of the small camera is blocked, and monitoring by the camera in the subsequent injection state becomes impossible, but the air in the unfilled cavity 12 is lost. The grout discharged from the upper end portion through the exhaust cylinder 40 and reinjected reaches the upper end of the unfilled cavity 12 and leaks into the vacuum-resistant container 25 through the exhaust cylinder 40. Grouting reinjection into the upper end of the unfilled cavity 12 can be confirmed by the leakage of the grout.

  Thus, after the grout refilling up to the upper end portion in the grout unfilled cavity 12 is completed, the suction by the vacuum pump 27 is stopped, and the insertion portion 31 of the endoscope 30 inserted into the grout unfilled cavity 12 is inserted. Pull out. At this time, by continuing the pressure injection of the grout, the grout refilling is completed without leaving a cavity after the insertion portion 31 inserted into the grout unfilled cavity 12 is extracted.

  In the above example, the vacuum pump is used to depressurize the upper end side of the unfilled cavity, but when the grout re-injection is completely performed only by the pressure injection by the grout pressure injection device, A vacuum pump may not be used.

a Existing grout b PC tendon.
DESCRIPTION OF SYMBOLS 10 PC structure 11 PC tension | tensile_strength material insertion sheath 12 Grout unfilled cavity 13 Grout pressurization injection port 14 Discharge port 15 Grout injection hose 16 Vacuum suction hose 20 Grout pressurization injection device 21 Open / close valve 25 Vacuum-resistant container 26 Open / close valve 27 Vacuum pump 30 Endoscope 31 Insertion section 32 Small camera 33 Monitor 34 Light 35 Operation section 36 Front opening 37 Operating instrument access port 40 Exhaust tube

Claims (3)

In the existing post-tension type PC structure, the grout pressure filling inlet for injecting the grout into the grout unfilled cavity in the sheath for inserting the PC tendon material and the air in the grout unfilled cavity are discharged. In the grout refilling method to the grout unfilled cavity in the sheath of the existing PC structure in which the grout pressure filling port is formed by pressurizing and injecting grout from the grout pressure filling port.
A small camera is provided at the distal end of the insertion section, and an endoscope is provided in which an operating device entry / exit path is formed inside the insertion section, and the distal end of the operation instrument entry / exit path is opened at the end surface of the insertion section. ,
Inserting the distal end of the insertion portion of the endoscope from the discharge port to the upper end side of the unfilled grout cavity while monitoring the inside of the unfilled cavity through the small camera,
The grout is pressurized and injected from the grout injection port by the grout pressure injection device while being exhausted through the operation port of the endoscope, to the unfilled grouting cavity in the sheath of the existing PC structure. Grout refill method.   The insertion portion of the endoscope is inserted into the grout unfilled cavity upper end side, and an exhaust pipe is inserted toward the upper end of the grout unfilled cavity from the operation unit insertion / removal port at the distal end of the insertion section. The method for refilling grout into a grout unfilled cavity in a sheath of an existing PC structure according to claim 1, wherein grout is pressurized and injected from the grout injection port by a grout pressure injection device while exhausting.   In a state where the exhaust pipe is inserted toward the upper end of the grout unfilled cavity, the gap between the exhaust pipe and the operation unit inlet / outlet is hermetically sealed, and the side end of the exhaust pipe not filled with the grout The grouting in the sheath of the existing PC structure according to claim 2, wherein the grouting state is reduced by a vacuum pump, and the grouting filling up to the upper end of the grouting unfilled cavity is sucked through the exhaust pipe to confirm the refilling state of the grouting How to refill grout into unfilled cavities.

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