JPS6325133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing an earth anchor in which a tensile member is embedded and fixed in anchor concrete poured into an anchor hole formed in the ground.

Generally, as shown in Fig. 1, in conventional earth anchors, a tensile member 2 is inserted into an anchor hole 1 drilled in the ground, and its tip is fixed to an anchor concrete 4 with a fixing device 3, and the fixed part is Passing the tensile material 2 into the sheath 5 at the open end side to prevent it from adhering to the anchor concrete 4,
It is known that the earth retaining plate 6 at the outer end is able to expand and contract according to the tensile load, and the load is supported in the deep layer.

In addition, as shown in Fig. 2, the exposed end 2a of the tensile member 2 is directly embedded in the anchor concrete 4 without using a fixing device, and is fixed by the adhesive force of the anchor concrete to the tensile member 2. is also known.

Among these conventional earth anchors, the one shown in Fig. 1 is advantageous in that it can securely anchor in deep areas, but it is expensive because it uses the anchoring body 3, and the anchor hole is small. There is a problem that it is not easy to insert the anchor concrete into the sheath 5, and in the case of the one shown in FIG. If it adheres to the anchoring length of the tensile material 2, the anchoring force will be extremely reduced, resulting in a lack of fixing reliability. Furthermore, when injecting unbonded grease into the sheath and inserting the tensile material 2, the anchoring length will It was necessary to work carefully to prevent foreign matter such as oil from adhering to the parts, which caused problems such as reduced work efficiency.

In view of these conventional problems, the present invention provides highly reliable deep anchoring when constructing an earth anchor that is anchored by the adhesion force of anchor concrete to tensile material, as shown in FIG. The purpose is to provide a construction method for earth anchors that is easy to work with on site, and its gist is to use tensile material whose outer surface is coated with unbonding grease and whose outer surface is coated with synthetic resin. A method for constructing an earth anchor in which the tip of the tensile member is made to protrude from the tip of the synthetic resin coating, and the protruding portion is directly buried and fixed in earth concrete, which is cast into an anchor hole drilled in the ground. In this step, unbonding grease is applied to the outer surface of the tension material for a length corresponding to the free length portion that insulates the tension material from the anchor concrete, and at the same time, unbonding grease is applied to the outer surface of the tension material for a length corresponding to the free length portion that insulates the tension member and the anchor concrete, and a length corresponding to the anchoring length portion that is directly fixed to the anchor concrete is applied. Using a tensile material in which the synthetic resin coating is continuously applied to the outer surface of the tensile material without applying the unbonding grease to the outer surface of the tensile material, The method of constructing an earth anchor is characterized by peeling off the synthetic resin coating and burying the anchor in concrete.

Next, an embodiment of the present invention will be described with reference to FIG. 3 and the following drawings.

In this embodiment, a coated wire 10 manufactured in advance at a factory is used. As shown in FIG. 3, this coated wire rod 10 has a synthetic resin coating 12 applied to the outer surface of a tensile material 11 made of stranded steel wire.
2 and the tensile material 11 are alternately provided with a free length portion 14 with unbonding grease 13 interposed therebetween to prevent the adhesion of both, and a fixing length portion 15 without the unbonding grease 13 interposed therebetween. part 1
4 and 15 are used, which are cut into negative units.

When using it, as shown in FIG. 4, the synthetic resin coating 12 of the fixed length portion 15 is peeled off, and an adhesive tape 16 is wrapped around the end of the synthetic resin coating 12 of the free length portion 14 to perform a waterproof treatment. .

The tension member 11 partially covered and exposed in this way is inserted into the anchor hole 17 drilled in the ground. Prior to this insertion, the lead anchoring length portion 15 is loosened into unit strands 15a, and the space between each unit strand 15a is partially expanded using a star-shaped spacer 18, and a steel ring 19 or a binding wire (Fig. (not shown) to tie together the spaces between each spacer 18 and their tips.The length of this anchoring length portion 15 should be such that it can be integrated with the anchor concrete and obtain sufficient stress depending on the required durable tensile force. It should be kept at a low temperature.

In this way, the tensile material 11 is inserted into the anchor hole 17.
After inserting the anchor concrete 20 from the entrance of the anchor hole 17, it is buried and solidified, and then a bearing steel material 22 is applied to the outside of the earth retaining material 21.
The outer end of the tensile material 11 is fixed to the outside thereof.

As in the past, this fixing involves a tapered hole into which the tensile material is inserted, and a tapered hole into which the tensile material is inserted.
Fixing tool 2 similar to the conventional one using a wedge that is clamped and fixed by being drawn in by the return force of the tensile material
Use 3.

The construction method of the earth anchor of the present invention is configured as described above, in which unbonding grease is applied to the outer surface of the tension member for a length corresponding to the free length portion that insulates the tension member and the anchor concrete, and the grease is applied directly to the anchor concrete. Using a tensile material in which the synthetic resin coating is continuously applied to the outer surface of the tensile material without applying the unbonding grease to the outer surface of the tensile material for a length corresponding to the fixing length portion to be fixed, the unbonding By peeling off the synthetic resin coating on the anchor length part that is not coated with the anchoring grease and burying it in the anchor concrete, at the construction site, you can easily remove the coating on the anchor length part and perform tensile stress. All you have to do is insert the material into the anchor hole, and there is no need to insert it into a sheath or do grouting, which is required in the past, which greatly simplifies the work on site.Moreover, the fixed length of the tensile material can be easily transported during storage. Because it is always covered, a clean state can be maintained without the adhesion of foreign substances such as oil that may have an adverse effect on the adhesion of concrete, and therefore, the fixing conditions for concrete that have been assumed in advance can be maintained. You will always get
This makes it possible to obtain a highly reliable deep fixation state.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a conventional earth anchor, FIG. 2 is a sectional view of another example, FIG. 3 is a partially cutaway sectional view of an example of a covered wire used in the method of the present invention, The figure is a partial sectional view of an earth anchor according to the method of the present invention. 10... Covered wire rod, 11... Tensile material, 12...
Synthetic resin coating, 13... Grease for unbonding,
14...Free length part, 15...Fixed length part, 16
... Adhesive tape, 17 ... Anchor hole, 20 ...
anchor concrete.

Claims (1)

[Claims] 1 Using a tensile material whose outer surface is coated with unbonding grease and whose outer surface is coated with synthetic resin, the tip of the tensile material projects from the tip of the synthetic resin coating, and the protruding part is drilled into the ground. In the construction method of an earth anchor, which is directly buried and fixed in the anchor concrete that is cast into the anchor hole, the tensile member is unbonded on the outer surface of the tensile member for a length corresponding to the free length portion that insulates the tensile member and the anchor concrete. At the same time, the synthetic resin coating is continuously applied to the outer surface of the tensile member without applying the unbonding grease to the outer surface of the tensile member for a length corresponding to the anchoring length portion to be directly fixed to the anchor concrete. 1. A method for constructing an earth anchor, which comprises using a tensile material applied using a tensile material, and embedding the synthetic resin coating in the anchor concrete after peeling off the synthetic resin coating of the anchor length portion to which the unbonding grease is not applied.