JP6948658B1 - Head cap structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head cap structure applicable to an environment in which stress concentration is high on a portion bolted to a bearing plate while using a material other than metal. It has a peripheral wall that surrounds the entire circumference of the fixing member (1,2,3), the top (11a) side of the peripheral wall is closed, and a collar portion (11b) is provided on the peripheral edge of the opening on the base side of the peripheral wall. The covering member (11) to which the seal member (13) is attached to the ground contact side surface of the collar portion (11b) is made of metal and abuts on the opposite surface of the ground contact side surface of the collar portion (11b). (11b) is fixed to the bearing plate (4) in a watertight state by a fixing member (12) that presses the bearing plate (4). [Selection diagram] Fig. 1

Description

The present invention provides a member for fixing the head of a ground anchor (hereinafter referred to as a tendon) to the ground in a ground anchor construction method used for ground stabilization measures for slopes and slopes to prevent landslides. It relates to a head cap structure for covering and protecting.

In the ground anchor method, a tendon (sometimes called a tendon tension material or a strand) composed of a head, a free length part, and an anchor body is used.

The anchor body has a function of fixing the tendon to the ground by injecting cement grout. Further, the free length portion is a portion for making the tendon in a stretchable and free state.

The head is a part for fixing the tendon on the surface of the ground to a pressure receiving structure such as a glue frame or a pressure receiving plate. Tension the tendon with a jack and fix it to the pressure receiving structure using a jig such as an anchor head or a wedge. In the state where the head is fixed to the pressure receiving structure, a tensile force acts on the tendon. Then, since the tensile force exerts a compressive force on the ground as its reaction force, unstable behavior such as landslide can be suppressed.

As a structure for fixing the head of the tendon to the pressure receiving structure, for example, a structure disclosed in Japanese Patent Application Laid-Open No. 11-181768 (hereinafter referred to as a crimping grip screw fixing type) is known. In this crimping grip screw fixing type, a cylindrical rigid load-bearing body (hereinafter referred to as an apartment) having a screw groove engraved on the outer periphery is crimped to the head of a tendon and fixed to be fitted on the outer periphery of the apartment. The head is fixed to the pressure receiving structure via a bearing plate (anchor plate) arranged between the nut and the fixing nut and the pressure receiving structure. Further, since the fixing nut and the apartment are screwed together, the tensile force can be adjusted by adjusting the position of the fixing nut.

On the other hand, as another structure, for example, a structure disclosed in Japanese Patent Publication No. 7-25364 (hereinafter referred to as a wedge anchor head fixing type with a ring) is known. In this wedge anchor head fixing type with a ring, a disk-shaped fixing body (hereinafter referred to as an anchor head) and a wedge having a male screw formed on the outer circumference and penetrating a steel material insertion hole having a tapered opening into which a wedge can be inserted. Can be used to fix the head to the pressure receiving structure via a bearing plate arranged between the anchor head and the pressure receiving structure. Further, the tensile force can be adjusted by adjusting the position of the nut screwed on the outer circumference of the anchor head.

Further, regardless of the structure of the crimping grip screw fixing type and the wedge anchor head fixing type with a ring (hereinafter, these structures are collectively referred to as "head fixing structure"), the head fixing structure is used. Since the head is exposed to the ground surface and is easily corroded, the head treatment specified in "Geotechnical Society Standards Ground Anchor Design and Construction Standards, Explanation" is applied. Specifically, a member for fixing the head of Tendon (anchor head, wedge, condominium, nut, etc., hereinafter referred to as "fixing member") is covered with a head cap, and an anticorrosive material such as rust preventive oil is contained in the head cap. Is filled.

Then, various methods for confirming the presence or absence of deterioration of the anticorrosion material filled in the head cap have been proposed. For example, in Japanese Patent No. 5916184, a cap with a window is formed of an outer shell member made of a non-transparent material and provided with an opening, and an inner shell member made of a transparent member, and the inside of the cap is formed. It has been proposed to see.

Japanese Unexamined Patent Publication No. 11-181768 Jitsufuku No. 7-25364 Japanese Patent No. 5916184

Japanese Geotechnical Society Standards Ground Anchor Design / Construction Standards, commentary

In order to make the inside of the head cap visible, the head cap must be made of a translucent material that enables the inside of the head cap, specifically, a resin, and is further filled. In order to prevent leakage of the anticorrosive material, it is necessary to fix the base of the head cap to the bearing plate with a bolt to make it watertight. However, in an environment where stress against an external force is concentrated on the portion bolted to the bearing plate and the degree of stress is increased, the head cap made of resin may lead to creep rupture. In addition, the oil used for fixing the bolt and adhering to the bolt may permeate the stressed portion and cause a solvent crack.

Therefore, the material of the head cap may have to be made of metal so as not to cause creep rupture or solvent crack due to stress concentration. Then, in order to visually recognize the inside of the head cap made of a non-transmissive metal, it is necessary to provide a portion where the inside can be visually recognized, specifically, a window portion.

However, in the prior art in which the window portion is provided on the head cap including the cap with a window, the transparent member for forming the window and the head cap body have a complicated structure in order to maintain the watertightness in the head cap. It was joined. Therefore, the number of parts increases, or the shape of the member becomes complicated, which causes a problem that it takes time and effort to manufacture and install.

Further, even when it is not necessary to visually recognize the inside, it may be preferable to use a material other than metal. For example, even if the shape is difficult to realize with metal, it may be possible to form it with synthetic resin, and the cost may be reduced.

Therefore, an object of the present invention is to provide a head cap structure that can be applied to an environment in which stress concentration is high at a portion bolted to a bearing plate while using a material other than metal.

The head cap structure according to the present invention has a peripheral wall that surrounds the entire circumference of the fixing member, the top side of the peripheral wall is closed, a collar portion is provided on the peripheral edge of the opening on the base side of the peripheral wall, and the flange portion is grounded. the cover member sealing member is attached to the side surface, is formed of metal, has a hole extending through the planar view centrally diameter capable inserting the cover member, the flange on the opposite surface of the ground side of the flange portion The flange portion is fixed to the bearing plate in a watertight state by a fixing member that abuts over the entire circumferential direction of the portion and presses the flange portion against the bearing plate.

The fixing member may have a protective wall extending along the peripheral wall of the covering member.

The protective wall of the fixing member may cover the entire peripheral wall of the fixing member.

In the head cap structure according to the present invention, the fixing member that presses the flange portion of the covering member against the bearing plate abuts on the opposite surface of the ground contact side surface of the flange portion, so that the stress is dispersed over the entire collar portion and the covering member is specified. Do not concentrate on the part. On the other hand, stress concentration occurs at a portion of the fixing member fixed to the bearing plate, but since the fixing member is made of metal, there is no possibility of creep rupture due to stress concentration. Further, since the fixing member is made of metal, there is no possibility that solvent cracks are caused by the permeation of oil used for fixing the bolt and adhering to the bolt. Therefore, the material for forming the covering member is not limited to metal, and can be formed of an appropriate material according to the purpose and application. That is, according to the present invention, it can be applied to an environment in which stress concentration is high on a portion bolted to a bearing plate while using a material other than metal.

The fixing member may have a protective wall extending along the peripheral wall of the covering member, in which case the strength of the entire structure can be increased. Therefore, it can be applied to places where individuals such as falling rocks may collide, such as mountain slopes.

The height dimension of the protective wall may be determined in consideration of the strength required for the entire structure in the installation environment. For example, if it is necessary to increase the strength as much as possible, the protective wall may be formed to cover the entire peripheral wall of the covering member. On the other hand, if the height dimension of the protective wall is smaller than the height dimension of the covering member, the material of the covering member is made to have translucency so that the inside can be visually recognized, so that the inside of the covering member can be visually recognized. It will be possible.

It is a front view which shows the embodiment of the head cap structure which concerns on this invention. It is a front view which shows the other embodiment of the head cap structure which concerns on this invention.

An embodiment of the head cap structure according to the present invention will be described with reference to FIG.
In the embodiment shown in FIG. 1, the anchor head fixing type is adopted as the head fixing structure. That is, in this embodiment, a disk-shaped anchor head 1 and a wedge 2 having a tapered wedge receiving portion into which the wedge 2 can be inserted and penetrating the tendon insertion hole are used, and the anchor head 1 and the pressure receiving structure are used. The head of the tendon 9 is fixed to the pressure receiving structure via the bearing plate 4 arranged between them.

Further, on the outer circumference of the anchor head 1, a nut screwed into a male screw formed on the outer circumference of the anchor head 1 (hereinafter referred to as "adjustment ring 3") is fitted on the outer circumference of the anchor head 1. Then, the tensile force of the tendon 9 can be adjusted by adjusting the position of the adjusting ring 3. In FIG. 1, the male screw formed on the outer circumference of the anchor head 1 is not shown.

Each of the constituent members of the wedge 2 is provided with a recess having a shape that matches the outer circumference of the tendon 9, and the recess is applied to the outer circumference of the tendon 9 to sandwich the tendon 9 between the two constituent members. As a result, the wedge 2 is arranged on the outer circumference of the tendon 9. Then, by fitting the wedge 2 into the wedge receiving port of the anchor head 1, the tendon 9 is fixed in a tense state. Since the shape of the wedge socket is known, the illustration and description will be omitted.

The tendon 9 is fitted with a water blocking member 6 that prevents water from entering through the gaps between the holes formed in the bearing plate 4. The wedge 2 is fixed to the end side of the tendon 9 with respect to the water blocking member 6.

The anchor head 1, the wedge 2, and the adjusting ring 3 correspond to the fixing member of the present invention, and the tendon 9 is fixed. These fixing members are covered with the head cap 10 together with the end portion of the tendon 9. ing. In FIG. 1, the cross section of the head cap 10 is displayed for easy understanding of the structure.

The head cap 10 is composed of a covering member 11 and a fixing member 12. The covering member 11 has an anchor head 1, a wedge 2, an adjusting ring 3, and a peripheral wall surrounding the entire circumference of the tendon 9. The top 11a side of the peripheral wall is closed by the ceiling wall, and the flange portion 11b is provided on the peripheral edge of the opening on the base side of the peripheral wall. Further, a seal member 13 is attached to the ground contact side surface of the flange portion 11b.

In this embodiment, an annular groove is provided on the ground contact side surface of the flange portion 11b, and the seal member 13 is fitted into the annular groove. However, there is no limitation on the method of attaching the seal member 13 to the ground contact side surface of the collar portion 11b, and other known methods may be appropriately used.

Further, the shape of the seal member 13 is not limited to the annular shape as long as the inside of the covering member 11 fixed to the bearing plate 4 can be maintained in a watertight state, and the head cap 10 is installed. It can be shaped to suit the situation.

Further, the material of the sealing member 13 is not limited as long as the inside of the covering member 11 fixed to the bearing plate 4 can be maintained in a watertight state, and a known material such as rubber can be used as the sealing material. ..

In this embodiment, a polycarbonate resin is used as the material of the covering member 11. And the inside can be visually recognized. However, the material of the covering member 11 is not limited, and may be appropriate in consideration of the properties and shape required for the usage environment, the manufacturing conditions, the economic efficiency, and the like.

For example, when economic efficiency is taken into consideration, resins such as polycarbonate, acrylic, polyethylene, and vinyl chloride may be used. Further, if there is concern about both corrosion due to rainwater and dew condensation and deterioration of ultraviolet rays, aluminum may be used, but if economic efficiency is also taken into consideration, the wall thickness may be thin. Since stress is not concentrated on a specific portion of the covering member 11, there is no risk of creep rupture even if the wall thickness is reduced.

The fixing member 12 is made of a metal annular member in which a hole having a diameter through which the covering member 11 can be inserted penetrates the center in a plan view. A plurality of bolt insertion holes 12a are provided around the through hole in the center of the plan view, and the diameter of the opening on the ground surface of the through hole is expanded to form a recessed portion 12b. Note that screw holes for bolts 14 for fixing the fixing member 12 to the bearing plate 4 are provided at positions corresponding to the plurality of bolt insertion holes 12a in the bearing plate 4.

Then, when the flange portion 11b of the covering member 11 is fitted into the recessed portion 12b and the fixing member 12 is bolted to the bearing plate 4, the bottom surface of the recessed portion 12b comes into contact with the opposite surface of the ground contact side surface of the flange portion 11b, and the collar portion 11b is pressed against the bearing plate 4 and fixed to the bearing plate 4 in a watertight state.

As long as the bolt insertion hole 12a is formed around the through hole through which the covering member 11 is inserted, there is no limitation on the position where the bolt insertion hole 12a is formed, and the bolt insertion hole 12a may be formed in consideration of the installation situation and the like. Although the bolt insertion hole 12a of this embodiment is formed in the annular member, a plurality of protrusions extending in a direction away from the annular member in a plan view are provided on the peripheral edge of the annular member, and the bolt insertion hole 12a is formed in the protrusion. You may.

The material of the fixing member 12 may be a metal having a strength that does not cause creep rupture due to stress concentration at a portion fixed to the bearing plate 4, that is, a portion where the head of the bolt 14 abuts, and is resistant to rust. For example, SUS, plated steel material, painted steel material, or aluminum may be used.

The fixing member 12 may have a protective wall for increasing the strength of the entire structure. FIG. 2 shows an embodiment in which the fixing member has a protective wall. In FIG. 2, substantially the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

The fixing member 22 of the embodiment shown in FIG. 2 has a protective wall 22a extending along the peripheral wall of the covering member. Then, the strength of the entire structure is increased by covering the entire peripheral wall of the covering member 11.

The height dimension of the protective wall 22a may be determined in consideration of the strength required for the entire structure in the installation environment. If the required strength is small, the height dimension of the protective wall 22a may be smaller than the height dimension of the covering member 11. In this case, the inside of the covering member 11 can be visually recognized through the tip end side portion of the covering member 11 exposed above the protective wall 22a.

Further, when there is a possibility that an external force acts on the top of the covering member 11 due to a collision such as falling rocks, the top side of the protective wall 22a may be closed to cover the ceiling wall of the covering member 11.

In the embodiments shown in FIGS. 1 and 2, the anchor head fixing type structure has the anchor head 1, the wedge 2, and the adjusting ring 3 as fixing members, but the fixing members are not limited, and the condominium and the condominium A crimping grip screw fixing type structure may be used in which a fixing nut fitted to the outer periphery of the is used as a fixing member.

1 Anchor head 2 Wedge 3 Adjustment ring (fixing nut)
4 Support plate 6 Water blocking member 9 Tendon 10 Head cap 11 Covering member 11a Top of peripheral wall 11b Brim portion 12, 22 Fixing member 12a Bolt insertion hole 12b Recessed part 13 Sealing member 14 Bolt 22a Protective wall

Claims (3)

It has a peripheral wall that surrounds the entire circumference of the fixing member, the top side of the peripheral wall is closed, a collar portion is provided on the peripheral edge of the opening on the base side of the peripheral wall, and a seal member is attached to the ground contact side surface of the flange portion. the covering member, formed of metal, said covering member has a hole extending through the planar view centrally through it diameter, contact around the whole circumference of the flange portion on the opposite surface of the ground side of the flange portion, A head cap structure characterized in that the flange portion is fixed to the bearing plate in a watertight state by a fixing member that presses the bearing portion against the bearing plate. The head cap structure according to claim 1, wherein the fixing member has a protective wall extending along a peripheral wall of the covering member. The head cap structure according to claim 2 , wherein the protective wall of the fixing member covers the entire peripheral wall of the fixing member.

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