JPH09195272A - Rust preventing device for anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rust preventing device having a wide applicability which is more simplified in structure, can ensure a satisfactory watertight state, and is not only applicable without hindrance when a sheath for covering the free length part of an anchor tendon is apt to deform, but also applicable to a type using no sheath. SOLUTION: A cylindrical auxiliary sheath 13 for protecting the upper part of an anchor tendon constituting an anchor body is formed of a waterproof elastic body. The base part on the head part side of the auxiliary sheath 13 is pressed and fixed among the insert hole part of a bearing plate 12, the peripheral part of the anchor tendon 2, and a fixture 8 side by the elastic deformation caused by pressing the upper end part of the auxiliary sheath 13 protruded from the surface of a bearing plate 12 by the fixture 8 of the anchor tendon 2, whereby the head part side of the auxiliary sheath 13 is held in watertight state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor rust preventive device used for stabilizing slopes. More specifically, the present invention relates to a rust preventive device for a connecting portion of an upper portion of an anchor body with an anchor head. Here, the anchor body is
An anchor means such as a so-called uncurtain don or a lock bolt, which is made of PC steel wire, PC steel stranded wire, deformed PC steel rod, etc., for transmitting a tensile force.

[0002]

2. Description of the Related Art Conventionally, as a rust preventive technique relating to a connection portion with an anchor head of this type, an upper end portion of a joint sheath is used as a pressure support plate and a pressure force from a fixing tool such as a nut is transmitted to the pressure support plate. The anchor head side and the sheath side are connected to each other by sandwiching them between the plate and the plate and joining the lower part to the outer peripheral surface of the sheath that covers the free length part of the uncurtain don, and further packing to the joint part. Japanese Patent Laid-Open No. 6-158657 discloses a technical means aiming at a more reliable watertight state by interposing an O-ring or an O-ring and further pressing and deforming the O-ring.

By the way, since the conventional joint sheath is not only structurally complicated, but it is premised on the connection with the sheath which covers the free length portion of the uncurtain don.
Since most of the entire length cannot be applied to an anchor of a type that does not use a sheath, such as a rock bolt embedded in a state of being in contact with the grout material, its applicable range is not so wide. Further, as a sheath for covering the free length portion of the uncurtain don, a relatively flexible material has been conventionally used, and since there are many deformable ones, a joint sheath is fitted from the outside of the sheath as in the prior art. In the method of making it, there is a problem that the sheath side is deformed at the time of fitting and the joint state with the joint sheath is impaired, and the watertight state between them is impaired. Further, since the joint sheath is located outside the sheath, the outer diameter of the joint sheath is large, and thus the insertion hole formed in the bearing plate also has a large diameter, which is not desirable. Further, when a pressure bearing pipe is used to deform the O-ring by pressing, there is a problem in that the structure of the joint sheath itself is further complicated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical circumstances, and has a simpler structure and can secure a good watertight state, and at the same time, the uncurtain don It is an object of the present invention to provide an anchor rust preventive device which has a wide adaptability and is applicable not only to the case where the sheath covering the free length portion of the above is easily deformed, but also applicable to the type not using the sheath. .

[0005]

In order to solve the above-mentioned problems, the present invention forms a cylindrical auxiliary sheath for protecting the upper portion of the anchor body with an elastic body having water resistance, and the head portion of the auxiliary sheath. The side is inserted into an insertion hole formed in the structure and the pressure bearing plate, and the upper end is projected from the surface of the pressure bearing plate,
An upper end portion of the auxiliary body is configured to be pressed via a fixing tool of the anchor body, and elastic deformation caused by pressing of the upper end portion of the auxiliary sheath by the fixing tool causes the base portion of the auxiliary sheath on the head side to be It is characterized in that the head side of the auxiliary sheath is kept in a watertight state by pressure-bonding and fixing it between the insertion hole portion of the pressure support plate, the outer peripheral portion of the anchor body and the fixing tool side. When applied to the type using the sheath, the tip of the auxiliary sheath is formed to have an outer diameter that can be fitted inside the end of the sheath that covers the free length of the uncurtain don, and It is also possible to function as the conventional joint sheath by pressing the upper end of the auxiliary sheath to press the tip of the auxiliary sheath inside the end of the sheath. Further, the auxiliary sheath may be formed of rubber, the tip portion thereof may be formed in a tapered shape, and a spherical washer may be interposed between the fixing tool and the auxiliary sheath.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is not restricted by the specific type of the anchor body, and can be widely implemented as a rust preventive means for the anchor. In other words, the uncurtain dong can be applied to those using various PC steel materials such as PC steel wire, PC steel stranded wire or PC steel rod, especially deformed PC steel rod. Further, it can be applied to an anchor of a type that does not use the sheath, such as a lock bolt, in which most of the entire length is buried in contact with the grout material. The auxiliary sheath uses its own elastic deformation to crimp the base portion on the head side between the insertion hole portion of the pressure support plate, the outer peripheral portion of the anchor body, and the fixing tool side. Therefore, it is formed by selecting an appropriate elastic material such as rubber or synthetic resin material having water resistance and having appropriate elasticity and strength suitable for its watertight action.

In practice, the difference between the outer diameter of the base portion of the auxiliary sheath on the head side and the inner diameter of the insertion hole of the pressure plate through which the base portion of the head side is inserted interferes with the insertion work. Set it small so that it does not come out. As a result, the base portion on the head side of the auxiliary sheath is pressure-bonded and fixed after the following process, and the watertight state is secured. That is, when the upper end portion of the auxiliary sheath is pressed through the fixing tool, the distal end portion of the auxiliary sheath is press-fitted inward of the sheath end portion, or in the case of a type that does not use a sheath, the distal end portion at that time. Since the portion is embedded and solidified in the grout material, a compressive force acts between both ends of the auxiliary sheath, and as a result, a predetermined elastic deformation occurs in the auxiliary sheath. Due to the elastic deformation, the contact state between the outer peripheral surface of the head side of the auxiliary sheath and the inner peripheral surface of the insertion hole of the pressure support plate gradually becomes tight, and when a biting state is eventually reached, the frictional force between them rapidly increases. To do. As a result, the base portion on the head side of the auxiliary sheath is locally elastically deformed by the subsequent pressing force of the fixing tool, so that between the insertion hole portion of the pressure support plate, the outer peripheral portion of the uncurtain don and the fixing tool side. It will be crimped and fixed. As a result, a good watertight state is obtained, and as a result, the distal end portion of the auxiliary sheath is supported in the end portion of the sheath or in the grout material, and the base portion on the head side is crimped and fixed. Since it is securely fixed, a very good supporting state can be obtained. Therefore, even when a displacement is applied due to an earthquake or the like, both ends of the auxiliary sheath are well supported and the displacement is absorbed by the elastic deformation of the intermediate portion, so that the influence can be reduced. In order to more securely fix the auxiliary sheath on the base side, the base portion is formed in a tapered shape, the outer surface is provided with irregularities, and the head portion upper end portion is a flange portion that abuts the upper surface of the pressure support plate. It is also possible to form the auxiliary.

When the free length portion of the uncurtain don is applied to the type covered with a sheath, the tip portion of the auxiliary sheath is press-fitted inside the end portion on the head side of the sheath as described above. The elastic contact keeps the fitting portion in a watertight state. in this case,
If a taper portion, a small diameter portion or the like is formed at the distal end portion of the auxiliary sheath so that it can be easily fitted inside the end portion of the sheath, it is extremely effective in terms of work.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an essential part of an anchor of the type in which an uncurtain don made of a deformed PC steel rod in the form of a full-screw bolt is adopted as an anchor body and a free length portion thereof is covered with a sheath as an embodiment of the present invention. FIG. 2 is a vertical sectional view showing the auxiliary sheath, and FIG. 3 is a left side view thereof. In the figure, reference numeral 1 denotes an anchor, and as an anchor body that controls the anchor action, an uncurtain don 2 made of a deformed PC steel rod in the shape of all screw bolts is used. As is well known, a lower half portion (not shown) is configured as a fixing portion by exposing the uncurtain don 2 or covering it with a corrugated sheath or the like. The anchor 1 is formed by a grout that is inserted into a hole 5 formed in the ground 4 such as a slope, and is injected into the exposed portion of the lower half uncurtain don 2 or inside or outside the corrugated sheath that covers the uncurtain don 2. It is fixed to the ground 4 via the anchor fixing body.

Further, in the figure, 6 is an anchor head of the anchor 1, which is disposed above the structure 7, and in the present embodiment, is a fixing tool 8 consisting of a nut screwed onto the upper part of the uncurtain don 2. And a rust preventive cap 9 for covering the fixing device 8 and the like. Then, due to the tightening by the fixing tool 8, a pressing force is applied to the structure 7 via the pressure bearing plate 12 composed of the convex spherical washer 10, the concave spherical washer 11 engaging with this, the square washer and the like. As a result, a tensile force acts on the uncurtain don 2 as a reaction. The cap 9 is a spherical washer 1
The male screw portion formed on the outer peripheral surface of 1 is screwed into the female screw formed on the lower inner peripheral surface of the male screw portion to be tightened and fixed to the pressure bearing plate 12. Furthermore, the cap 9
A liquid sealing means such as an O-ring is attached to the lower surface of the, and the inside is filled with rust preventive oil and the like.

Next, the characteristic part of this embodiment will be described. As shown in FIG. 1, the uncurtain don 2
The above-mentioned auxiliary sheath 13 is disposed between the upper end of the sheath 3 covering the free length portion of the above and the lower surface of the spherical washer 10 pressed by the fixing tool 8. This auxiliary sheath 13
As described above, is formed by selecting an appropriate elastic material such as rubber or synthetic resin material having water resistance and elasticity and strength suitable for the watertight action, and the distal end portion thereof is formed by the sheath 3 Is formed with an outer diameter that can be fitted inside the upper end of the.
FIG. 2 shows an example of the specific shape of the auxiliary sheath 13. As shown in the figure, in this embodiment, the outer surface of the distal end portion of the auxiliary sheath 13 can be easily fitted inside the upper end portion of the sheath 3. A tapered portion 14 is formed. Further, a thick portion 15 is formed on the base side, and four thin plate-like projections 16 are formed on the inside thereof as shown in FIG. It is configured to be temporarily supported by.

When mounting the auxiliary sheath 13, the uncurtain don 2 is inserted into the drilled hole 5 as shown in FIG. 1, and the free length portion is covered with the sheath 3 first. The auxiliary sheath 13 is inserted into the uncurtain don 2 from above, and is formed at the tip end of the uncurtain don 2 with a gap between the through hole formed in the pressure support plate 12 and the structure 7 and the outer peripheral part of the uncurtain don 2. The tip of the taper portion 14 is inserted into the end portion of the sheath 3 on the head side, that is, the inside of the upper end portion, and is pushed in from above to be fitted. After that, the spherical washers 10 and 11 are set, and a nut as the fixing tool 8 is screwed into the uncurtain don 2 to start tightening. As a result, the pressing force is exerted on the structure 7 through the engagement of the concave and convex spherical surfaces of the spherical washers 10 and 11 and the pressure bearing plate 12, and as described above, a predetermined tensile force acts on the uncurtain don 2 as a reaction thereof. become.

When the fixing tool 8 is tightened, the upper end surface of the auxiliary sheath 13 is pressed through the lower surface of the spherical washer 10, and as a result, the taper portion 1 at the tip of the auxiliary sheath 13 is pressed.
4 will be fitted even more firmly inside the upper end of the sheath 3. Along with this, a large compressive force gradually acts on the thick portion 15 formed on the base portion on the head side, and as described above, due to elastic deformation of the thick portion 15, the outer diameter is changed. As a result, the phenomenon of biting between the pressure bearing plate 12 and the through hole occurs, and the frictional force sharply increases. Therefore, the thick portion 15 is further locally elastically deformed by the pressing force of the fixing tool 8 thereafter, and the auxiliary sheath 1
The head side base of 3 is the insertion hole portion of the bearing plate 12, the outer peripheral portion of the uncurtain don 2, and the spherical washer 10 that is the fixing tool 8 side.
It will be fixed by crimping with the lower surface of the. Therefore, as described above, the tip of the auxiliary sheath 13 is securely press-fitted into the upper end of the sheath 3, and the base of the auxiliary sheath 13 is supported by the bearing plate 1.
Since it is pressure-bonded and fixed between the insertion hole portion of 2, the outer peripheral portion of the uncurtain don 2 and the lower surface of the spherical washer 10 which is the fixing tool 8 side, the head side of the auxiliary sheath 13 is completely sealed, which is extremely favorable. A rust preventive effect will be obtained.

In the above-mentioned embodiments, the case where the present invention is applied to the anchor using the uncurtain don as the anchor body has been described as an example. However, as described above, the present invention adopts the lock bolt or the like as the anchor body, It can also be applied to an anchor of the type that does not use the sheath. Also, as the uncurtain don 2, instead of the deformed PC steel rod, another PC such as PC steel wire or PC steel stranded wire is used.
It can also be applied to anchors made of steel. When the present invention is applied to an anchor of a type that does not use the sheath, if the distal end portion of the auxiliary sheath 13 is buried by injecting and solidifying the grout material, and then tightened through the fixing tool 8, As in the case of the above-described embodiment, the base portion of the auxiliary sheath 13 is the insertion hole portion of the pressure bearing plate 12, the outer peripheral portion of the lock bolt or the like which is the anchor body, and the fixing tool 8.
It will be fixed by crimping with the lower surface of the spherical washer 10 which is the side. Therefore, since the base portion on the head side of the auxiliary sheath 13 is completely sealed, similarly excellent anticorrosive action can be obtained. The specific shape and strength of the auxiliary sheath 13, the magnitude of the elastic coefficient, and the like may be appropriately selected according to the application scene.

[0015]

According to the present invention, the following effects can be obtained. (1) The auxiliary sheath is formed of an elastic body, and the base portion on the head side is crimped and fixed between the insertion hole portion of the pressure support plate, the outer peripheral portion of the anchor body, and the fixing device side by elastic deformation of the auxiliary sheath itself. Since it is configured as described above, a reliable watertight state can be secured by a simple configuration, and a good rust preventive action can be obtained. (2) Since the auxiliary sheath can be applied not only to the case where the sheath is used but also to the type of anchor not used, its adaptability is large. (3) Since both ends of the auxiliary sheath are securely held, an extremely good supporting state can be obtained. (4) Since the auxiliary sheath has a simple structure and its outer diameter can be suppressed to be small, it is effective for reducing the diameter of the insertion hole formed in the structure or the bearing plate and the anchor head. (5) Since a method of press-fitting the tip of the auxiliary sheath into the inside of the sheath to connect the two is adopted, even if the sheath is flexible, it is surely joined in a watertight state while expanding from the inside. Therefore, the trouble as in the past does not occur. In addition,
In that case, it is effective in press-fitting work if the tip portion of the auxiliary sheath is formed in a tapered shape.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a vertical sectional view of an auxiliary sheath used in the same example.

FIG. 3 is a left side view of the auxiliary sheath.

[Explanation of symbols]

1 ... Anchor, 2 ... Uncurtain Don, 3 ... Sheath, 4
… Ground, 5… Drilling, 6… Anchor head, 7… Structure, 8
... Fixing tool, 9 ... Cap, 10 ... Convex spherical washer, 1
DESCRIPTION OF SYMBOLS 1 ... Concave spherical washer, 12 ... Pressure support plate, 13 ... Auxiliary sheath, 14 ... Tapered part, 15 ... Thick part, 16 ... Thin plate-shaped protrusion

Claims (5)

[Claims] 1. A tubular auxiliary sheath for protecting an upper portion of an anchor body is formed by an elastic body having water resistance, and a head side of the auxiliary sheath is inserted into an insertion hole formed in a structure, a pressure plate and the like. It is configured such that the upper end portion is inserted and protrudes from the surface of the pressure support plate, and the upper end portion can be pressed through the fixing tool of the anchor body, and the upper end portion of the auxiliary sheath is pressed by the fixing tool. Due to the elastic deformation, the base portion on the head side of the auxiliary sheath is pressure-bonded and fixed between the insertion hole portion of the pressure support plate, the outer peripheral portion of the anchor body, and the fixing tool side, so that the head side of the auxiliary sheath is watertight. Anchor rust preventive device characterized by holding in the state. 2. The outer diameter of the auxiliary sheath is formed so that it can be fitted inside the end of the sheath that covers the free length of the uncurtain don, and the upper end of the auxiliary sheath is pressed by the fixing tool. The anchor rust preventive device according to claim 1, wherein the distal end portion of the auxiliary sheath is press-fitted inside the end portion of the sheath. 3. The anchor rust preventive device according to claim 2, wherein the tip portion of the auxiliary sheath is formed in a tapered shape. 4. The rust preventive device for an anchor according to claim 1, wherein the auxiliary sheath is made of rubber. 5. The anchor rust preventive device according to claim 1, wherein a spherical washer is interposed between the fixing device and the upper end portion of the auxiliary sheath.