JPH0583015U - Terminal fixing structure for rockfall prevention fence - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A very secure and stable terminal fixing state is obtained,
The purpose of the present invention is to provide a rockfall prevention fence terminal fixing structure that is easy to install and does not require skill to easily check the quality of fixing. [Structure] A terminal support 1 and an intermediate support 2 are built on the foundation of the slope foot, and a plurality of cables 4 are erected between these supports, and a wire mesh 5 is stretched behind the cable to receive rockfalls in a fence. The outer circumference of the end portion of the cable is gripped and fixed by a winding grip 7, and the ring portion of the winding grip is fastened to a holding metal fitting 8 attached to a terminal support.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a terminal fixing structure for a rockfall prevention fence.

[0002]

[Prior art and its technical problem]

 It is often installed under steep slopes such as roads and railroads.In this case, as a means to protect against falling rocks, columns are installed at regular intervals, and cables are laid between the columns in multiple stages and wire mesh is stretched. A rockfall prevention fence, which is installed and absorbs rockfall energy by elastic expansion of cables and compositional deformation of columns, is widely used. In this type of rockfall prevention fence, wedge socket type cable end fittings have been conventionally used to fix the cable end to the column. However, when such a cable end fitting is used, the socket is passed through the cable, the tip of the cable is broken into strands, a wedge is inserted, the wedge is tapped into the tapered hole of the socket, and the adjustment rod is inserted from the other end of the socket. It is a series of operations in which the nuts are inserted and connected so that the tips press the wedges. At that time, considerable skill is required for fitting the wedge into the cable so that the twist of the cable does not return and for controlling the wedge. For this reason, the construction is troublesome, time-consuming and labor-intensive, and it is difficult to check whether the fixing is sufficient because the wedge fits inside the socket, and the fixing effect tends to vary depending on the skill level. There was a problem. Furthermore, when the fixed part is to be removed for re-installation due to improper fixing, the cable must be cut, which may make it impossible to secure the required cable length, resulting in a problem of poor material yield. Then, when a rock fall occurs, the cable is pressed in the direction perpendicular to the axis. At that time, the wedge socket type applies a concentrated load to the socket mouth portion, and the cable is likely to be sheared. Therefore, even if the load was smaller than the set breaking load of the cable, the cable was cut from the socket mouth portion, and there was concern about the effect of absorbing rockfall energy. The present invention was devised to solve the above-mentioned problems, and the purpose of the present invention is to obtain a very reliable and stable terminal fixing state, and the construction is simple and requires no skill. It is intended to provide a rockfall prevention fence terminal fixing structure that makes it easy to check the quality of fixing.

[0003]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is a fence that receives terminal rocks by installing terminal columns and intermediate columns on the base of a slope, laying cables in multiple stages between these columns, and installing a wire mesh behind the cables to receive rockfall. In the body, the outer circumference of the end of the cable is gripped and fixed by a winding grip, and the ring portion of this winding grip is fastened to a holding metal fitting attached to a terminal support.

[0004]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a rockfall protection fence to which the present invention is applied. Reference numeral 1 is a terminal support pillar, and 2 is an intermediate support pillar, which is built on a concrete foundation 3 at the boundary between the foot of the slope A and the road or railway. 4 is a cable made of wire rope, which is arranged in multiple stages in the height direction. Each end of the cable is fixed to the terminal column 1 by the terminal fixing mechanism 6, and the intermediate region is an intermediate column by U bolts. It is held at 2. Reference numeral 5 denotes a wire mesh, which is stretched on the back side of the terminal support 2 and the intermediate support 3.

The terminal fixing mechanism 6 is shown in FIGS. 2 to 5, and comprises a winding grip 7 and a holding metal fitting 8. The cable 4 comprises, for example, a plated wire rope of 3 × 7 construction, and the wrapping grip 7 is wound around the cable end 40 over a length greater than 5 times the diameter. On the other hand, the terminal support 1 is made of H-shaped steel or the like, and the holding metal fitting 8 is a shank type in this embodiment. That is, the rod portion 80 of the holding metal fitting 8 is inserted into the hole of the web provided depending on the installation interval, and the rod portion 80 of the holding metal fitting 8 is wrapped around the yoke-shaped retaining portion 81 fixed to the tip of the rod portion by welding or the like. The portion 7a is inserted, and the ring portion 7a is hooked by the pin 82 inserted into the retaining portion 81. A thimble 83 is preferably attached to the ring portion 7a as shown in FIG. The nut 9 is screwed into the rod portion 80, and the nut 9 is rotated to move the holding metal fitting 8 in the axial direction, so that the cable tension is set and adjusted. FIG. 6 shows another embodiment. In this embodiment, an eyebolt type is used, the rod portion 80 is provided with a hole 84, and the ring portion 7a is inserted into this hole.

As shown in FIG. 4, the wrapping grip 7 has two flattened wires formed by arranging a plurality of (for example, 5 to 7) steel wires on the same plane and twisting the steel wires in a spiral shape. It has gripping feet 7b, 7b ', and a U-turn portion 7a' having a rigid twist structure is formed at the tip of the gripping feet 7a, 7b. An appropriate friction agent is applied to the inner surfaces of the gripping feet 7b and 7b '. The cable end portion 40 is positioned so as to hang on the start end of the U-turn portion 7a ', and one grip foot 7b is first wrapped around the outer circumference of the cable end portion as shown in Fig. 4, and the grip foot 7b is wrapped. The other grip foot 7b 'is wound so as to do so. As a result, a terminal portion having the ring portion 7a is formed as shown in FIG. In the embodiment of FIGS. 2 and 3, after the ring portion 7a is formed in this manner, it is fastened to the holding metal fitting 8. In the embodiment of FIG. 6, one of the gripping feet 7a or 7b is passed through the hole 84 of the rod portion 80 in advance, and then the gripping feet 7b and 7b 'are wound around the cable end portion 40 as described above. A vertical wire 50 is passed through the end of the wire net 5 and is fixed to the terminal support 1 by a U bolt 51. In addition, a horizontal wire is passed through the wire net 5 and fixed by the slits of the slit bolts attached to the intermediate column 2.

[0007]

[Operation of the embodiment]

 In the present invention, a rockfall protection fence is constructed as shown in FIG. 1, and when there is a rockfall from the slope, it is absorbed by the elastic elongation of the cable 4 and the plastic deformation of the stanchions and the deformation of the wire mesh. A large load is applied due to the collision of falling rocks. In the present invention, the holding metal fitting 8 is attached to the terminal support 1, and the ring portion 7a of the grip 7 is wound around the holding metal fitting 8 and the cable 4 is attached to the end portion 40 of the flat gripping feet 7b, 7b '. The gripping feet 7b, 7b 'exert a strong tightening force (gripping force) and friction in the radial direction by the gripping feet 7b, 7b', and are further pulled rearward by the holding metal fitting 8 via the ring portion 7a. 7b 'becomes tighter and more gripping force increases, so strong and stable holding power is obtained. The ring portion 7a is capable of swinging in a vertical plane with the pin 82 of the holding metal fitting 8 as the center, so that when a rockfall collides, it concentrates on the socket mouth like in the case of a wedge type socket. The phenomenon of load does not occur, and the terminal fixing force equivalent to or higher than the standard load of the cable can be exerted. According to the experiments conducted by the present inventors, when a cable diameter is 8 mm, a winding grip having five strands and a strand diameter of 2.48 mm is used, and the grip length (from the root of the ring portion to the end of the short side foot) is used. When the length was 486 mm, a holding force of 3700 kgf (1.05% of the standard load) was obtained. Also, when the cable diameter is 12 mm and the winding grip is 6 wires and the wire diameter is 3.20 mm and the grip length is 915 mm, the holding power of 11500 kgf (about 1.04% of the standard load) is obtained. Was obtained. Furthermore, when the cable diameter is 18mm and the winding grip with 6 strands and 4.19mm strand diameter is used and the grip length is 1135mm, the holding force of 17900kgf (about 1.1% of standard load) is obtained. Was obtained. This is a significantly higher holding force than the conventional wedge socket type.

[0008]

[Effect of the device]

 According to the present invention described above, in the fence body that receives the falling rocks by arranging the terminal support and the intermediate support on the foundation of the slope foot, laying the cables between the supports in multiple stages, and arranging the wire mesh behind the cable to receive the falling rocks. The outer circumference of the end of the cable 4 is gripped and fixed by the winding grip 7, and the ring portion 7a of the winding grip 7 is fixed to the holding metal fitting 8 attached to the terminal support 1, so that the following excellent effects can be obtained. Be done. It can be easily installed without requiring skill. In the present invention, two flat gripping feet 7b, 7b 'twisted in a spiral shape of the winding grip 7 are wound around the cable end portion 40, and the ring portion 7a formed thereby is attached to the holding metal fitting 8. It's extremely easy because it only needs to be fastened, requires no skill, and requires no special tools. The terminal fixing is strong and stable, and the quality of holding power can be judged from the outside at a glance. In the present invention, the two flat gripping feet 7b and 7b 'of the spiral shape wind the cable in a wide area from the outer circumference, and the tightening force is further increased by pulling the cable to the ring portion 7a. The holding force is equal to or more than the cutting load of the cable. Further, since it is sufficient to simply wind the cable around the outer circumference of the cable, there is no influence by the skill level of the operator, and a predetermined holding force can always be realized without variation. Further, the fixing portion is entirely exposed, and the holding force can be judged only by checking whether or not the gripping feet 7b, 7b 'are wound without any gap, so that the inspection can be easily performed at the completion of the work or after that. Reconstruction can be easily done without cutting the cable. When the fixing is released, the two flat gripping feet 7b, 7b 'may be removed from the cable 4, and it is not necessary to cut it like a wedge socket, so that the cable length is not shortened. It can be constructed at low cost. Since the present invention has only the winding grip 7, the holding metal fittings and the nut, the number of parts is small, and the work is easy as described above, so that the construction can be carried out at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a structure for fixing an end of a rockfall prevention fence according to the present invention.

FIG. 2 is a side view of a terminal fixing structure for a rockfall prevention fence according to the present invention.

3 is a cross-sectional view of FIG.

FIG. 4 is a side view showing the connection between the cable end portion and the winding grip.

FIG. 5 is a side view showing a terminal fixing completion state.

FIG. 6 is a side view showing another embodiment of the terminal fixing structure of the rockfall prevention fence of the present invention.

[Explanation of symbols]

 1 Terminal Support 2 Intermediate Support 4 Cable 7 Winding Grip 7a Rings 7b, 7b 'Grip Feet 8 Holding Metal

Claims (3)

[Scope of utility model registration request] 1. A fence in which a terminal support and an intermediate support are built on a foundation at the foot of a slope, a plurality of stages of cables are erected between the supports, and a wire mesh is stretched behind the cable to receive rockfall, and the cable is used. The end fixing structure of the rockfall prevention fence, characterized in that the outer circumference of the end is gripped and fixed with a grip, and the ring part of this grip is fastened to a holding metal fitting attached to the terminal support. 2. The holding metal fitting has a rod portion and a yoke portion fixed to the tip of the rod, and the ring portion of the winding grip is inserted into the yoke portion and fixed by inserting a pin into the yoke portion. The terminal fixing structure for a rockfall prevention fence according to claim 1, which includes one. 3. The terminal fixing structure for a rock fall prevention fence according to claim 1, wherein the holding metal fitting includes a rod portion having a hole, and the ring portion of the winding grip is inserted.