JP2799666B2 - Anchor maintenance method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor maintenance method for investigating, grasping and managing the soundness of anchors used for ground anchor construction.

[0002]

2. Description of the Related Art For example, in ground anchor work, anchor tension members such as PC steel strands that have been tensioned by a tensioning device or the like are tensioned at a predetermined load by a fixing tool having a combination of an anchor head and a fixing wedge. In the state of being held, it is fixed to a target structure such as the ground via an anchor plate (support plate). Fixed by fixing device
The end (head) of the PC steel strand is usually covered with a head cap (also referred to as an oil cap) mainly for rust prevention and protection together with the anchor head.

Here, after the anchor is installed, if harmful rust, corrosion, damage, or the like occurs in the PC steel strand for pulling and anchoring the anchor, or if the tensile strength due to the PC steel strand decreases, the anchor may be damaged. Function may be reduced. Therefore, the maintenance of anchors to check the soundness of anchors by investigating and observing the presence or absence of rust, corrosion, damage and tensile strength by PC strands is usually performed on anchors after construction.

[0004]

As a method of examining the soundness of a PC steel stranded wire at a place where the appearance is not recognizable, such as inside an anchor, for example, ultrasonic flaw detection using an ultrasonic flaw detector or the like is known. Are known. In such a method, it is possible to investigate and grasp rust, corrosion, damage, etc. of the free length of the PC steel stranded wire by exploring the inside of the anchor based on data etc. from the ultrasonic probe etc. Is done.

[0005] However, when an actual inspection was carried out by ultrasonic flaw detection, a sufficient reaction was found in the damaged portion, but it was difficult to react in a small corroded portion generated immediately below the head fixing portion, and the corrosion state was poor. In some cases, sufficient judgment cannot be made. In other words, in the known method for maintaining and controlling the anchor by ultrasonic testing, there is a possibility that a detailed situation investigation of a place where the appearance is impossible may not be sufficiently performed, which is not preferable in terms of safety.

Here, it is conceivable that a microscope is inserted into the anchor hole, and the situation inside the anchor hole is examined by visually observing an image from the microscope.
However, in such a configuration, it is necessary to secure a considerable space in the vicinity of the fixing device, so that the anchor hole has a complicated shape, and it is difficult to drill the hole, which makes it very difficult to put it to practical use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for maintaining and controlling an anchor which can accurately and easily check the soundness of an anchor tension member.

[0008]

In order to achieve this object, according to the present invention, an investigation member of the same quality as the used anchor tension member is provided over the free length of the anchor tension member in the anchor hole at the time of anchor installation. , Is removably inserted in advance into the anchor head. Then, only the inspection member is extracted as necessary, and the soundness of the anchor tensile member can be inspected and grasped by visual inspection of the inspection member.

[0009]

According to the present invention, any state of rust, corrosion and damage of the anchor tensile material in the anchor hole can be generally determined by visually checking the extracted inspection member.
The soundness of the anchor tension material can be accurately grasped.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, in the method for maintaining and controlling an anchor according to the present invention, a survey member 14 of the same quality as an anchor tensile member 12 of an anchor 10 is attached to an anchor hole 18 of a target structure 16 such as the ground. And is detachably inserted in advance.

In the anchor 10, an anchor tension member 12, for example, a PC steel strand, fixed and fixed at one end by a grout 20 or the like in the anchor hole is subjected to a predetermined load by a tensioning device (not shown) or the like. The PC steel stranded wire is tensioned and fixed at a predetermined load by fixing the anchor head 24 to the PC steel stranded wire at a location adjacent to the anchor plate (support plate) 22 so that the PC steel stranded wire can be sunk into the ground (object structure). ) 16 has been established.

The end (head) of the PC stranded wire (anchor tension member) 12 fixed by fixing the anchor head 24 is usually fixed to a head cap (oil) mainly for rust prevention and protection. An anchor 10 that is covered with an anchor head by a cap 26 and stabilizes the ground 16 and the like is configured.

The structure of such an anchor 10 is well-known, and the structure itself is not the purpose of the present invention, and will not be described in detail here.

By the way, in such an anchor 10, in order to keep the anchor in a healthy state at all times, the condition of the PC steel stranded wire 12 inside the anchor hole 18, that is, the presence or absence of rust, corrosion, damage, etc., is checked. For example, it is necessary to regularly investigate and understand.

Therefore, in the present invention, as shown in FIG. 1, for example, a PC steel stranded wire having the same quality as the PC steel stranded wire 12 used for the anchor 10 is used as the investigation member 14 for the anchor hole 18. It is detachably inserted. As can be seen from FIG. 2 in addition to FIG. 1, the investigation member (PC steel strand) 14
Is inserted so as to be able to be extracted without using an anchor head by using, for example, one insertion hole 28 of a series of insertion holes of the anchor head 24.

As shown in FIG. 1, the investigation member 14 is formed with a free length of the PC steel strand inside the anchor hole 18, that is, a length located over the distance between the anchor head 24 and the grout 20. And is inserted into the anchor hole.

According to the anchor 10 having such a configuration, it is possible to arbitrarily extract only the investigation member 14 after the anchor is installed. Then, the inspection member 14 extracted from the anchor hole 18 as necessary is directly visually observed, and the degree of soundness of the PC steel strand 12 is grasped from the rust, corrosion, damage and the like of the inspection member. This is the anchor maintenance method according to the invention.

That is, according to the anchor maintenance method of the present invention, the PC steel stranded wire 12 inside the anchor hole 18 can be visually inspected by the inspection member 14 extracted as necessary.
Rust, corrosion, damage, etc.
Oversight of details can be reliably prevented, and accurate investigation and grasp of the soundness of the PC stranded wire can be easily performed.

Therefore, the maintenance and management of the anchor 10 becomes reliable and easy.
That is, the safety of the anchor itself is sufficiently improved.

In this method, it is sufficient to insert and insert the same kind of PC steel stranded wire as the investigation member 14 into the conventional anchor 10 without complicating the anchor itself. This does not complicate construction work.

Furthermore, since the soundness of the PC steel strand can be checked without using various measuring instruments such as an ultrasonic probe, the work is not complicated and an inexpensive check is possible.

After the completion of the survey, the survey members 14
The survey members were used to easily return the
The inspection of the soundness of the PC steel strand 12 can be repeated.

Incidentally, since such an anchor 10 merely inserts the investigation member 14 into the anchor hole,
In various investigations and measurements of other parts such as a soundness investigation of the anchor head and a measurement of the remaining effective tensile force, a known method can be sufficiently executed.

Here, in the embodiment, a PC stranded wire is embodied as the anchor tensile member 12, but the present invention is not limited to this. For example, an anchor using a PC steel rod as an anchor tensile member is also investigated. When the member 14 is made of the same PC steel rod, the method for maintaining and managing the anchor of the present invention can be applied.

The embodiments described above are for explaining the present invention, and do not limit the present invention in any way.
It goes without saying that all modifications and alterations within the technical scope of the present invention are included in the present invention.

[0027]

As described above, according to the method for maintaining and controlling an anchor according to the present invention, the inspection member pulled out can be visually inspected from the rust, corrosion, damage, etc. of the anchor tensile material in the anchor hole. Because you can roughly grasp the degree of health,
The maintenance and management of the anchor becomes reliable and easy, and the safety of the anchor itself after the installation of the anchor is sufficiently improved.

Since it is sufficient to additionally insert a research member of the same quality as the anchor tension member into the anchor hole, the anchor itself is not complicated, and the construction work of the anchor is not complicated.

Further, since the soundness of the anchor tension member, which cannot be visually observed in appearance, can be checked without using various measuring instruments such as an ultrasonic probe, the work is not complicated and an inexpensive check is possible. Becomes

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an anchor, in which the method for maintaining and controlling an anchor according to the present invention is possible.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

 10 Anchor 12 Anchor tensile material (PC steel strand) 14 Inspection member (PC steel strand) 18 Anchor hole 24 Anchor head

Claims (1)

(57) [Claims] 1. An anchor maintenance method for examining at least the state of rust, corrosion and damage of an anchor tensile material to grasp the integrity of the anchor, comprising: At the anchor hole in the free length of the anchor tensile material in the anchor hole, detachably insert in advance to the anchor head, pull out only the investigation member as necessary, and visually inspect the inspection member to check the soundness of the anchor tension material An anchor maintenance method characterized in that it can be grasped.