JPH07217394A - Rock-bolt cap and use thereof - Google Patents

Abstract

PURPOSE:To cover the front end of a rock bolt projected from a primary lining concrete surface in tunnel construction, etc., and a nut with a cap and to prevent the damage in a cut-off sheet spreading on the surface of them. CONSTITUTION:A cylindrical bolt insertion 4 into which the front end of a rock bolt 10 projecting from a primary lining concrete surface B directing an opening 3 to the inside of the central part of a cap main body 2 formed in a semispherical shape and a cylindrical nut insertion 6 inserting a nut 12 screwed in the front end of the rock bolt 10 and engaging with the nut 12 are successively formed to constitute a rock bolt cap 1. The front end of the rock bolt 10 is inserted in the bolt insertion 4 of the rock bolt cap 1, the nut 12 screwed in the rock bolt 10 is inserted in the nut insertion 6, and the front end of the rock bolt 10 projected from the primary lining concrete surface, the nut 12 and the surrounding thereof are covered with the rock bolt cap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock bolt cap for covering a tip portion of a lock bolt protruding from a concrete surface of a primary lining constructed by covering a surface of a formation in tunnel construction, and a method of using the cap. It is a thing.

[0002]

2. Description of the Related Art The so-called NATM construction method (NATM construction method) has been conventionally adopted as a tunnel construction method in which concrete is sprayed onto the excavated surface in the excavated tunnel to maintain its strength. This NATO method generally increases the strength of the tunnel, prevents leakage in the tunnel, and collects and drains the leaked water, and then installs a primary lining by spraying concrete and a waterproof sheet on the concrete surface by this primary lining. After being stretched, it is constructed by a secondary lining that further strengthens by spraying concrete onto the surface of the impermeable sheet. When the concrete is sprayed by the primary lining, it is customary to drive rock bolts into the ground at appropriate intervals in order to loosen the ground and improve the strength of the primary lining concrete to be placed. This lock bolt has its tip projected on the concrete surface of the primary lining and is tightened to the concrete surface by tightening a nut on this tip with a washer and tightening it on the concrete surface. After laying a non-woven fabric for cushioning and a synthetic resin waterproof sheet on the entire surface in order,
The concrete is sprayed again by the secondary lining. In order to reinforce the concrete sprayed at the time of placing this secondary lining concrete, an anchor bolt for reinforcing bar is separately driven into the ground, and the anchor bolt for reinforcing bar is composed of the non-woven fabric and the waterproof sheet. After penetrating and taking appropriate water leakage prevention means at the penetrating portion and attaching reinforcing bars to the tips of the anchor bolts to arrange the bars, secondary lining concrete is sprayed.

[0003]

In such NATO method, the tip of the lock bolt and the nut are exposed on the concrete surface of the primary lining. Therefore, when laying a synthetic resin waterproof sheet on this primary lining concrete surface via a buffering non-woven fabric, the tip of the protruding rock bolt breaks through the buffering non-woven fabric and There is a problem that the water-impervious sheet that is stretched is frequently brought into contact with the water-impervious sheet and the water-impervious sheet is ruptured, and it takes time and labor to repair water leakage from the ruptured portion. Even if it is possible to stretch the impermeable sheet with the tip of the lock bolt protruding, a large load acts on the impermeable sheet when placing the secondary lining concrete, resulting in The tip of the lock bolt protruding to the front may break through the water-blocking sheet and cause water leakage.

In view of the above situation, the present invention is an easy-to-handle cap for a lock bolt which can prevent breakage of a water-blocking sheet or the like by being attached to the tip of the lock bolt protruding on the surface of the primary lining concrete. It is intended to provide the usage of this lock bolt cap.

[0005]

To achieve this object, a cap for a lock bolt according to the present invention locks toward the opening inside a central portion of a hemispherical synthetic resin cap body. A cylindrical bolt insertion part into which the tip of the bolt can be inserted and a cylindrical nut insertion part that is retained by the nut by inserting a nut screwed into the lock bolt are integrally connected. It is a feature.

Further, another lock bolt cap of the present invention is a cylindrical shape in which the tip of the lock bolt can be inserted toward the opening inside the central portion of the cap main body made of synthetic resin formed in a hemispherical shape. The bolt insertion part and the cylindrical nut insertion part that is inserted into the lock bolt and is retained by the nut are integrally connected, and the inner peripheral surfaces of the bolt insertion part and the nut insertion part In addition, a plurality of ribs are integrally formed at predetermined intervals along the tube length direction.

Further, according to the method of using the lock bolt cap of the present invention, the tip of the lock bolt can be inserted toward the opening inside the central portion of the synthetic resin cap main body formed into a hemispherical shape. Located on the inner back side of the lock bolt cap in which the cylindrical bolt insertion part and the cylindrical nut insertion part that holds the nut by inserting the nut screwed into the lock bolt are integrally connected Insert the tip of the lock bolt protruding from the primary lining concrete surface into the insertion part, and insert the nut screwed into the lock bolt into the nut insertion part located on the opening side to hold the cap main body on the nut. Thus, the lock bolt and nut protruding from the concrete surface of the primary lining and the peripheral portion thereof are covered.

In the present invention, the cap main body constituting the lock bolt cap is formed by using a synthetic resin material such as polyethylene, polypropylene or polyvinyl chloride. Basically, the cap main body has a cylindrical bolt insertion part projecting inside the center part into which the tip of the lock bolt can be inserted toward the opening part. A tubular nut insertion portion into which a nut screwed to the lock bolt is inserted is provided, and the cap main body is held by the nut by the engagement between the nut and the nut insertion portion.

The tubular bolt insertion portion and the tubular nut insertion portion formed integrally with the cap main body are different depending on the diameters of the lock bolt and the nut protruding from the surface of the primary lining concrete. By forming plate-shaped ribs integrally on the inner peripheral surfaces of the cylindrical bolt insertion part and the cylindrical nut insertion part with a predetermined interval in the cylinder length direction, lock bolts and nuts with different diameters can be used. Can also be applied. At this time, the ribs have their lower end portions inclined toward the peripheral wall of each insertion portion, so that the lock bolt or nut can be smoothly inserted into the tubular insertion portion.

When the tip of the lock bolt protruding from the concrete surface of the primary lining is inserted into the cylindrical bolt insertion portion formed mainly of the cap, the length of the bolt is longer than that of the cylindrical bolt insertion portion. When the length is long, the tip end portion of the lock bolt protruding according to the length of the cylindrical bolt insertion portion is cut.

[0011]

The lock bolt cap of the present invention allows the tip end of the lock bolt protruding from the surface of the primary lining concrete in tunnel construction to be inserted into the bolt insertion portion formed inside the cap main body and screwed to the lock bolt. The cap nut is also inserted into the nut insertion part, and the cap main body is held by the engagement between the nut and the nut insertion part, so the tip of the lock bolt protruding from the surface of the primary lining concrete can be easily and It can be easily covered.

The method of using the lock bolt cap of the present invention is to insert the tip of the lock bolt projecting from the concrete surface of the primary lining into the bolt insertion portion provided mainly in the cap and to insert the nut into the nut insertion portion. ,
The lock bolt, the nut, and the peripheral portion thereof are mainly covered with a cap to prevent breakage of the non-woven fabric or the waterproof sheet due to the protrusion of the lock bolt.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The lock bolt cap of the present invention and its method of use will be described in more detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a lock bolt cap of the present invention.
A hemispherical cap main body 2 made of polyethylene, and a tubular part 5 inside the central part of the cap main body 2 toward the opening 3.
To form a bolt insertion part 4 inside, and to add a step part to the cylindrical part 5 to enlarge its diameter to form a cylindrical part 7.
Is formed, and the inside of the tubular portion 7 is used as the nut insertion portion 6.

That is, an annular concave groove portion 8 having a predetermined width and depth is integrally formed on the curved surface near the top of the cap main body 2, and the cap main body 2 is formed by molding the concave groove portion 8.
The inside of the tubular portion 5 formed integrally with the inside of the central portion of the hollow portion 5 facing the opening 3 is a bolt insertion portion 4, and a tubular shape having a larger diameter than the bolt insertion portion 4 is formed on the back surface of the bottom surface of the recessed groove portion 8. Part 7
Is integrally formed and the inside thereof is used as a nut insertion portion 6 which is screwed to a bolt. Although the tip of the tubular portion 7 in FIG. 1 projects slightly below the opening edge of the cap main body 2, it may be at the same level as or inside the opening 3.

The cap main body 2 has an outer diameter of about 120 m.
m, the height from the opening 3 to the top is about 40 mm, the tubular portion 5 has an inner diameter of about 23 mmφ, a length of about 29 mm, and the tubular portion 7.
Has an inner diameter of about 41 mmφ and a length of about 23 mm. Therefore, the applicable diameters of the bolts and nuts inevitably need to be substantially the same as the size of the tubular portion 5 or 7.

Lock bolt cap 1 having such a structure
Is specifically used by the method described below. That is, as shown in FIG. 6, after placing the primary lining concrete layer B on the natural ground A, the rock bolt 10 is driven into the natural ground A. Then, after the tip of the driven rock bolt 10 is projected onto the surface of the primary lining concrete layer B, the nut 12 is inserted through the washer 11 onto the tip of the lock bolt 10 protruding onto the surface of the primary lining concrete layer B. Is fastened to the surface of the concrete layer 11 to fix the rock bolt 10. Next, the tip of the lock bolt 10 and the nut 1 protruding from the primary lining concrete layer B
After covering the portion 1 with the lock bolt cap 1, the entire surface of the primary lining concrete layer B including the portion 1 of the lock bolt cap 1 is covered with a buffering non-woven fabric C, and the surface thereof is further covered with a synthetic resin. A water impervious sheet D made of a sheet is stretched, and a secondary lining concrete layer (not shown) is sprayed on the surface of the water impervious sheet D. At that time, as shown in FIG. 2, the lock bolt cap 1 shown in FIG. 1 has the tip of the lock bolt 10 fitted into the bolt insertion portion 4 formed by the tubular portion 5, and the nut 12 is tubular. When inserted into the nut insertion part 6 formed by the part 7, at least the outer peripheral part of the nut 12 engages with the inner peripheral part of the nut insertion part 6, so that the cap main body 2 is retained in the nut 12, and as a result, for the lock bolt. The cap 1 covers the tip of the bolt 10, the nut 12, and the peripheral portion thereof. By using the lock bolt cap 1 as described above, the arcuate surface of the cap main body 2 is smoothly connected to the surface of the primary lining concrete layer B, and the protruding tip portion of the lock bolt 10, the nut 12, and the peripheral portion thereof. Since the non-woven fabric C and the water-impervious sheet D are stretched, the non-woven fabric C and the water-impervious sheet D are not damaged and the tensioning work can be carried out very smoothly.

Another lock bolt cap 2 of the present invention
As shown in FIG. 3, 1 has a ring-shaped groove 28 having a predetermined width and depth toward the opening 23 near the top of a polyethylene hemispherical cap body 22. The inside of the tubular portion 25 formed by the above is used as a bolt insertion portion 24, and a tubular portion 27 having a diameter larger than that of the tubular portion 25 is formed on the rear surface of the bottom of the concave groove portion 28.
The nut insertion portion 26 is formed inside. Then, four ribs 29 having a constant width are integrally formed on the inner peripheral surface of each tubular portion 25 at a predetermined interval in the tubular length direction, and the inner peripheral surface of the tubular portion 27 is formed. Further, twelve ribs 30 having a constant width are integrally formed at a predetermined interval in the cylinder length direction. These ribs 29, 30
In order to facilitate the insertion of bolts and nuts, the lower end portion is inclined toward the inner peripheral wall, the cap main body 22 has a diameter of about 118 mmφ, a height of about 40 mm, and the bolt insertion portion 25 has a height of Is about 20 mm, inner diameter is about 25 mm
The width of the rib 29 is about 2 mm, the height of the nut insertion portion 27 is about 25 mm, the inner diameter is about 41 mm, and the width of the rib 30 is about 5 mm.

The lock bolt cap 21 having such a structure
Is specifically used by the method described below. This lock bolt cap 21 has the same size when the specifications of the lock bolt and the nut used therefor are different, for example, when the M22 lock bolt including the nut is used and when the M24 lock bolt is used. The lock bolt cap can be shared. That is, when the M22 lock bolt 40a having a small diameter is used, the tip of the lock bolt 40a is inserted into the bolt insertion portion 24 of the lock bolt cap 21 and the nut 42a is inserted into the nut insertion portion as shown in FIG. The lock bolt 4
The tip of 0a is held in contact with the rib 29 formed in the bolt insertion portion 24, and the nut 42a is held in contact with the rib 30 formed in the nut insertion portion 26. In addition,
41a is a washer.

Next, the lock bolt cap 21
When applied to the M24 lock bolt 40b having a large size, the tip end of the lock bolt 40b is fitted into the nut insertion portion 26 in the same manner, and the tip end crushes the rib 29 formed on the bolt insertion portion 24. And the nut 42b is inserted and held in a state in which the rib 30 formed in the nut insertion portion 26 is crushed, and in each case, the opening sides of the ribs 29 and 30 are expanded in a tapered shape. Therefore, the tip of the lock bolt and the nut are smoothly fitted, and the mounting is easy. Note that 41b is a washer.

[0020]

The lock bolt cap of the present invention is
Inside the center of the hemispherical cap body, a cylindrical bolt insertion part for inserting the tip of the lock bolt protruding from the surface of the primary lining concrete, and the lock bolt is fixed to the surface of the primary lining concrete The simple structure of integrally connecting the nut insertion part that inserts the nut for the construction to the primary lining in the tunnel construction covers the tip of the lock bolt protruding from the surface of the concrete and the nut, and the primary lining It is possible to prevent breakage of the non-woven fabric or the waterproof sheet stretched over the concrete surface.

Particularly, even if the diameters of the bolts and nuts are slightly different, ribs having a predetermined width are evenly arranged inside the bolt insertion portion and the nut insertion portion with a predetermined spacing. Since it can be used, it is extremely versatile. Moreover, since the nut insertion portion of the lock bolt cap engages with the nut,
Since the holding means for surely covering the lock bolt and the nut and the peripheral portion thereof mainly by the cap is not required, the handling is extremely simple and easy, and the working efficiency can be greatly improved.

The lock bolt cap according to the present invention can be used as a lock bolt by inserting the tip of the lock bolt protruding from the concrete surface of the primary lining into the bolt insertion portion and the nut into the nut insertion portion. The nut and its peripheral portion can be surely covered by the cap, so that the non-woven fabric and the waterproof sheet can be stretched safely and easily.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a lock bolt cap of the present invention.

FIG. 2 is a vertical cross-sectional view showing a usage example of the lock bolt cap of FIG.

FIG. 3 is a vertical sectional view showing another example of the lock bolt cap of the present invention.

FIG. 4 is a vertical cross-sectional view showing an example of use of the lock bolt cap of FIG.

FIG. 5 is a vertical cross-sectional view showing another example of use of the lock bolt cap of FIG.

FIG. 6 is an explanatory diagram showing a relationship between a primary lining and a water-blocking sheet in constructing a tunnel.

[Explanation of symbols]

 1 Cap for Lock Bolt 2 Cap Main Body 3 Opening 4 Bolt Insertion Section 5, 7 Cylindrical Body 6 Nut Insertion Section 8 Recessed Groove Section

Claims (5)

[Claims] 1. A cylindrical bolt insertion portion into which a tip portion of a lock bolt can be inserted toward an opening, inside a central portion of a cap main body made of a synthetic resin formed in a hemispherical shape, and screwed to the lock bolt. A cap for a lock bolt, wherein the nut is inserted and a tubular nut insertion portion held by the nut is integrally connected. 2. A cylindrical bolt insertion portion into which a tip portion of a lock bolt can be inserted toward an opening, inside a central portion of a cap main body made of a synthetic resin formed in a hemispherical shape, and screwed to the lock bolt. And a cylindrical nut insertion part that is retained by the nut and are integrally connected to each other, and at predetermined intervals along the cylinder length direction on the inner peripheral surfaces of the bolt insertion part and the nut insertion part. A cap for a lock bolt, characterized in that a plurality of ribs are integrally formed in the structure. 3. A cylindrical bolt insertion portion into which a tip portion of a lock bolt can be inserted toward an opening, inside a central portion of a synthetic resin cap main body formed in a hemispherical shape, and screwed to the lock bolt. And a cylindrical nut insertion part that is retained by the nut and are integrally connected to each other, and at predetermined intervals along the cylinder length direction on the inner peripheral surfaces of the bolt insertion part and the nut insertion part. And a lower end portion integrally formed with a plurality of ribs that are inclined in the peripheral wall direction of each of the insertion portions. 4. A cylindrical bolt insertion portion into which the tip of the lock bolt can be inserted toward the opening, and the lock bolt are screwed inside the central portion of the cap main body made of a synthetic resin formed in a hemispherical shape. Lock that protrudes from the primary lining concrete surface at the bolt insertion part located on the inner back side of the lock bolt cap that integrally connects the cylindrical nut insertion part that holds the nut by inserting the nut A lock protruding from the concrete surface of the primary lining by inserting the tip of the bolt and inserting the nut screwed into the lock bolt into the nut insertion part located on the opening side to hold the cap main body on the nut. A method of using a cap for a lock bolt, which is characterized by covering a bolt, a nut, and a peripheral portion thereof. 5. A cylindrical bolt insertion portion into which the tip of the lock bolt can be inserted toward the opening, inside the central portion of the cap main body made of a synthetic resin formed in a hemispherical shape, and screwed to the lock bolt. And a cylindrical nut insertion part that is retained by the nut and are integrally connected to each other, and at predetermined intervals along the cylinder length direction on the inner peripheral surfaces of the bolt insertion part and the nut insertion part. , The lower end of the lock bolt cap integrally formed with a plurality of ribs inclined in the circumferential wall direction of each of the insertion portion, from the primary lining concrete surface to the bolt insertion portion located on the inner back side Insert the protruding tip of the lock bolt and bring the nut that is screwed into the lock bolt into the nut insert located at least on the opening side to contact the rib provided on the nut insert or crush the rib. A method for using a cap for a lock bolt, characterized in that the cap main body is held by the nut by means of the above, and the lock bolt and the nut protruding from the surface of the primary lining concrete and the peripheral portion thereof are covered.