JP2002047650A - Set anchor body and executing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor used for fixing a prevention net for rock fall used for sediment ground and having large resistance force for load and excellent durability. SOLUTION: The set anchor body 50 installed as the anchor for fixing the prevention net for rock fall to the ground 100 such as a sloping surface has a plurality of steel rods 20 inserted into each of a plurality of holes 10 provided in a row on the ground 100 and a head fixing tool 30 provided with a plurality of steel rod through holes for penetrating the head part of each steel rod 20 and installed within the excavated hole. In a gap of each steel rod 20 and the ground 100 and a gap of the head part fixing tool and the ground 100, grout is filled. When the head part fixing tool is hollow, grout is filled in also the fixing tool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor for fixing a rock-fall preventing net or a rock-fall preventing fence on a slope or a slope of earth and sand ground.

[0002]

2. Description of the Related Art In Japan, which has many mountainous areas, slopes and slopes are present in various places, and countermeasures against falling rocks, falling rocks, and avalanches are important issues. Conventionally, rock fall prevention nets, rock fall prevention fences, and the like are often installed on slopes or the like as specific countermeasures against rock fall. For example, a method has been adopted in which a target slope or the like is entirely covered with a net formed of a strong wire material such as a wire rope, and the periphery of the net is securely fixed to the slope or the like using an anchor.

[0003] Various anchors are used to fix the above-mentioned net to a slope or the like. The anchor is
Even if a load of a falling object is applied to the net due to falling rocks or the like, the net must be securely fixed so that the load does not detach the net from the slope or the like. That is, it is important that the anchor itself is not damaged or pulled out.

FIG. 10 schematically shows some examples of a conventional anchor. FIG. 10A shows an expansion bolt 110 used when the slope or the like is rock. Drill a pilot hole in the rock of ground 100
And the nut is tightened to open the bolt tip quadrant (not shown) and fix it to the bedrock. FIG.
(B) to (D) show examples of anchors used when the ground is made of relatively soft ground, for example, earth and sand ground. FIG. 10B shows a driving-type anchor with blades. The winged anchor comprises wings 122 consisting of two flat plates extending in opposite directions to the axis of the rod. On the head of the anchor 120, a wire rope attaching portion 123 is provided.
Is provided. Since the blade 122 is a flat plate, the blade 122 effectively exerts resistance when a force is applied perpendicularly thereto. FIG. 10C shows a drive-in type assembly anchor. The assembly anchor uses a plurality of steel rods, which are connected in a row by a steel rod connector 132. A wire rope attachment portion 133 is provided near the center. This assembly anchor effectively exerts resistance when a force is applied perpendicular to the connecting direction. FIG. 10D illustrates a concrete anchor. Concrete anchors are built on slopes, etc.
It is expected from the friction at the bottom and the earth pressure at the front.

[0005]

However, regarding the anchor steel rod used for the above-mentioned earth and sand ground, FIG.
Driving types such as (B) and (C) are made of steel, and have a problem in maintaining the anticorrosion performance. Normally, steel bars are hot-dip galvanized, but since they are driven directly into the ground, the hot-dip galvanization may be damaged at the time of casting, and there is a concern that the anticorrosion function may deteriorate. Was. Also, if there is a stone in the soil, it will not be able to be driven, and the construction site must be changed.

Further, in the concrete anchor shown in FIG. 10 (D), digging on a slope and placing concrete has a problem that workability and work efficiency are not good. In particular, large-scale excavation is required for a high-angle slope, which is practically impossible. In light of this situation,
An object of the present invention is to provide an anchor which is used for fixing a rock fall prevention net or the like used for earth and sand ground other than a bedrock, which has a large resistance to a load and has excellent durability.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an anchor installed on a rock mass to fix a rock fall prevention net or a rock fall prevention fence to a slope or a slope other than a bedrock. The present invention provides a set anchor body formed by combining a plurality of components and a construction method for installing such a set anchor body on a ground. 1) A set anchor body according to the present invention includes a plurality of steel bars inserted into each of a plurality of holes arranged in a row, a triangle or a cross in a ground, and a head provided in the ground. A head fixing device installed in the fixing device burying portion. The head fixing device is provided with a plurality of steel rod through holes through which the respective heads of the plurality of steel rods respectively penetrate. Furthermore, it has a gap between each of the plurality of steel bars and the ground, and a grout filled in the gap between the head fixture and the ground.
Preferably, the head fixing device is a substantially rectangular parallelepiped, substantially triangular or substantially cross-shaped hollow box or groove, and the inside of the box or the groove is also filled with grout. Further, the head fixing tool may be one in which a plurality of steel rod through holes are provided in a ready-made steel material such as an H-shaped steel, a square steel pipe, a grooved steel, or the like.

[0008] 2) Preferably, at least one of the plurality of steel bars is relatively longer than the other steel bars. 3) Also preferably, each of the plurality of steel bars is a steel bar provided with an anticorrosive coating. 4) Further, it is preferable that the steel rods are fixed by plates and nuts below and above the head fixing tool with each of the heads of the plurality of steel rods penetrating the head fixing tool. More preferably, at least one of the plurality of steel rods penetrates a winged void tube driven into the ground below the head fixture.

[0009] 5) The method of constructing the anchor assembly according to the present invention is a method for embedding a head fixing device, wherein a plurality of head fixing device burying portions for embedding the head fixing device and a plurality of extending from the bottom surface of the head fixing device burying portion in a vertical direction or a slope direction. Holes are excavated in the ground, a plurality of steel rods are inserted into each of the plurality of holes, the heads of the plurality of steel rods are respectively penetrated, and the head fixture is inserted into the head fixture embedding portion. Installed in Further, grout is filled in the gap between each of the plurality of steel rods and the ground, and the gap between the head fixture and the ground.

6) As another construction method, a head fixing part burying part for burying a head fixing part and a single row, triangle or cross shape extending in a vertical direction or a slope direction from the bottom surface of the head fixing part burying part. After digging a plurality of holes arranged in a plurality of holes, first, each of the plurality of holes is filled with grout, and then a plurality of steel rods are inserted. Then, the head fixture is installed in the head fixture embedding part by penetrating the head of each of the plurality of steel rods. Further, grout is filled in a gap between the head fixing device and the ground.

7) In the method of 5) or 6), when a substantially rectangular parallelepiped, substantially triangular or substantially cross-shaped hollow box or groove is used as the head fixing device, the box or the hollow Grout is also filled into the inside of the groove body. Also, preferably,
At least one of the plurality of holes is drilled relatively deeper than the other holes, and a steel rod relatively longer than the other steel bars is inserted into the relatively deeply drilled hole. Further, preferably, each of the plurality of steel bars is fixed by a plate and a nut below and above the head fixture. When excavating a hole, it is preferable to drive a feathered void tube into the opening of the hole.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a structure of an embodiment of a set anchor body 50 according to the present invention installed on a slope or the like. FIG. 1A is a top view of the set anchor body 50. 1B is a cross-sectional view taken along a line 1-1 in the top view, and FIG. 2 is a cross-sectional view taken along a line 2-2 in the top view. The main components of the braided anchor body 50 are a plurality of steel rods 20,
The head fixing box 30.

In the embodiment, the plurality of steel rods 20 use lock bolts, have a diameter of 19 mm to 52 mm, and are made of steel and have a hot-dip galvanized finish. These steel rods are
It is inserted into a hole 10 that has been drilled to zero. The plurality of holes 10 are arranged in a row. The plurality of steel bars may be all the same length, but preferably, at least one of the plurality of steel bars is relatively longer than the others as shown. In the example shown in the figure, one at the center is long and two at both sides are short. This long steel rod is used to pull out in an extreme state, that is, to provide resistance to a load in the axial direction of the steel rod. And other short steel rods work effectively to suppress deformation under normal load. That is, it exerts a resistance against a load perpendicular to the steel rod axis direction. Of course, not only short steel rods but also long steel rods contribute to this resistance to normal loads.

As described above, in the anchor set 50 of the present invention, at least one relatively long steel bar and another short steel bar can provide the resistance force of the plurality of steel bars in two steps. The effective resistance force of the steel rods connected and fixed in a plurality of rows is obtained by providing the head fixing box 30. Note that the steel bar 20 includes not only a round steel bar but also a deformed steel bar, and also includes a hollow steel bar.

The head fixing box 30 shown in FIG. 1 is a substantially rectangular parallelepiped hollow casing, and is installed in the embedded portion 12 for embedding the fixed box formed in the ground 100. This head fixing box 30
In the longitudinal direction, a plurality of steel rods in a row are respectively fixed so as to pass therethrough. Further, the grout 40 is filled in the gap between the head fixing box 30 and the ground 100, and the grout 42 is also filled in the head fixing box 30. Grout includes, for example, cement, water, and admixtures. Alternatively, it may be mortar. In order to perform grout filling efficiently,
Is provided with an air vent hole 32 as appropriate. The grout 44 is also filled in the gap between the steel bar 20 and the ground 100. By filling the grout into the gap with the ground, the assembled anchor body 50 having strong adhesion to the ground can be obtained. Further, since the steel bar 20 is protected by the grout, a further anticorrosion effect is obtained in addition to the hot-dip galvanization coated on the steel bar itself. In addition, the anticorrosion coating of the steel bar 20 is as follows.
Not limited to hot-dip galvanizing, an appropriate anticorrosive coating technique can be used. In addition, the head fixed box 30 and the ground 10
With the grout 40 between 0 and 0, the earth pressure resistance on the front surface of the solidified body can be generated.

The lower nut 21 and the lower plate 22 attached to the steel bar 20 improve the stability of the head fixing box 30 by placing the lower plate 22 on the bottom of the head fixing box buried portion. The upper plate 25 and the upper nut 26 are fixed together with the lower plate 22 and the lower nut 21 by firmly fixing the steel rod 20 to the head fixing box 30.
Strengthens the integrity of the set anchor body 50.

FIG. 3 is a perspective view of the head fixing box 30 before construction. The steel rod through-holes 31 for penetrating the steel rods are arranged in a line in the longitudinal direction by the number of the steel rods. This head fixing box is hollow before construction. An air vent hole 32 is also formed in advance. Finally, since the grout is filled in the hollow portion, a hole for grout filling may be separately provided as appropriate.
If the diameter of the steel rod through-hole 31 is appropriate, grout can be filled from here.

The head fixing box 30 shown in FIGS.
The shape is an example, as long as it is a member for firmly fixing each head of the plurality of steel bars in the lateral direction, other shapes such as a shape having a groove-shaped space without being limited to the box. Is also good. For example, H
By providing a through-hole for inserting a steel rod in a steel material such as a mold steel, a square steel pipe, a grooved steel, or the like, it can be used as a head fixing tool. Even when these steel materials are used, the gap between these head fixing devices and the ground is sufficiently filled with grout.

FIG. 4 is a view showing an example of a construction procedure for installing the anchor set 50 of the present invention shown in FIGS. 1 and 2 on a slope. The upper figure in each figure is a top view, and the lower figure is a cross-sectional view taken along the line 1-1 in the top view. First, as shown in FIG. 4 (A), a ground 100 is excavated and dug down, and a buried portion 12 for burying a head fixing box and a hole 10 for a steel rod are provided. At this time, as an example of the drilling direction, as shown in FIG. 2, the bottom surface of the head fixing box burying portion 12 is horizontal.
There is also a method of excavating so that the hole 10 is in a vertical direction. In another example, the hole 10 may be in a direction perpendicular to the excavation bottom surface, that is, in a slope direction. As a preferable procedure, first, the fixed box buried portion 12 is dug down, the head fixed box 30 is temporarily installed in the fixed box buried portion 12 (dotted line), and the head fixed box 30 is passed through the steel rod through hole 31 provided in the fixed box 30. Drill with a drill. In this case, the positions of the holes are not shifted, and the efficiency is improved. When the drilling is completed, the temporarily installed head fixing box 30 is once taken out of the buried portion 12. Since the head fixing box 30 is hollow and lightweight as shown in FIG. 3, such work can be easily performed.

Next, as shown in FIG. 4B, a steel rod 20 is inserted into the hole 10. The lower nut 21 and the lower plate 22 are attached to the steel bar 20. The nut and the plate may be attached in advance and then inserted. Further, as shown in FIG. 4C, the head fixing box 30 is installed in the fixing box burying portion 12. The steel rod 20 passes through the steel rod through hole 31 of the head fixing box. Finally, the upper surface of the head fixing box is
And the upper nut 26.

In the construction procedure shown in FIG. 4, the gap between the steel rod 20 and the hole wall of the hole 10, the gap between the head fixing box 30 and the hole wall of the fixing box burying part 12, and the inside of the head fixing box 30 Grout filling may be performed in a process that can sufficiently fill these gaps and is suitable for the operation.

For example, after the fixed box burying portion and the hole are provided,
It is preferable to first inject grout into the hole and then insert the steel rod. In this way, even if grouting occurs when the grout is poured into the drilling hole and water and solid components are separated, this breathing occurs in the buried portion around the reservoir-shaped fixed box, so that it is sure that the inside of the hole is not filled. The solidified component of the grout flows into the grout. As a result, the gap between the steel rod and the ground can be uniformly filled with grout, and the anchoring property of the steel rod can be ensured and the corrosion prevention can be enhanced.
Further, after the head fixing box is installed, the gap between the head fixing box and the ground is sufficiently filled with grout. In addition, grout is filled into the head fixed box at the same time.

FIG. 5 schematically shows an example in which the anchor assembly 50 according to the present invention is applied to the installation of a rockfall prevention net 60. The rock fall prevention net 60 is installed so as to cover the entirety of the rock or the rock 70 that may fall on a slope or the like. The rockfall prevention net 60 has a net-like structure in which a plurality of wire ropes are stretched vertically and horizontally and their intersections are connected to each other, and is fixed by connecting both ends of each wire rope to the anchor set 50 according to the present invention. For example, in the case of the anchor set 50 shown in FIGS. 1 and 2, it is preferable to connect both ends of each wire rope to the head of the steel bar 20 at the center of the anchor set 50. In FIGS. 1 and 2, attachment parts such as hooks and metal fittings for connecting a wire rope to the head of the steel rod 20 are omitted, but any attachment parts can be provided as appropriate. As shown in FIG. 5, the connection is basically performed such that the longitudinal direction of the set anchor body 50 matches the direction of the wire rope.

FIG. 6 is a schematic view for explaining the operation of the anchor set according to the present invention. FIG. 6A shows the ground 1
00 shows the state where no load is applied to any steel rod for anchor installed at 00. That is, the steel rod 20 or FIG. 10 (B) or (C) in the anchor assembly of the present invention.
Are the conventional anchors 120, 130. When wire ropes such as rock fall prevention nets are connected to the heads of these steel rods for anchors, the load when rock fall etc. occurs,
It extends in the direction perpendicular to the axis of the anchoring steel rod, that is, in the lateral direction. At this time, the conventional anchors 120, 130
As shown in FIG. 6 (B), in the ground of earth and sand, only the portion near the anchor head, that is, only a portion at a relatively shallow depth is deformed, and is largely bent in the direction of the load. This is because the anchor head moves freely. On the other hand, as shown in FIG. 6 (C), the steel rod 20 of the assembled anchor body according to the present invention has a structure in which the head cannot be deformed by the head fixing box and the grout, so that a load is applied to the head. In some cases, the head is not easily deformed. Even when an extremely large load that moves the head is applied, there is little deformation near the steel rod head due to the grout-filled head fixing box. The rod will be deformed.

The resistance of the anchor to the load is substantially obtained by the resistance of the deformed portion of the steel bar from the surrounding ground. Therefore, in the conventional anchor, sufficient resistance cannot be obtained because the thickness of the ground around the deformed portion of the steel bar is relatively thin and the bend is large. Since the ground extends to a deep depth, the surrounding ground is thick and does not bend greatly, so that a large resistance can be obtained. Further, generally, the deeper the depth, the harder the surrounding ground and the greater its resistance. Therefore, in the anchor set of the present invention, an extremely large resistance force is realized.

FIG. 7 shows conventional standard anchors A and B.
It is a graph (for example, what is shown to FIG.10 (B)) and the test result which measured the displacement amount of the anchor head, ie, the steel bar head, with respect to the load in the set anchor body of this invention. The ground is an embankment with an N value of 2. However, the conventional standard anchors A and B are data for one anchor 1.7 indented with respect to the ground. It is data on a combination of three lines, two of which are rooted at 0.7 m. As a simple comparison, the total length of the steel rod in the braided anchor body is 1.8 times that of the standard anchor, so that the braided anchor body should provide at least 1.8 times the resistance of the standard anchor. . However, referring to the results in FIG. 7, it can be seen that the set anchor body of the present invention requires 5 to 6 times the load to generate the same displacement as the standard anchor. This indicates that the anchor set of the present invention exerts a large resistance far exceeding the resistance obtained by the difference in the total length of the steel rods.

In another test, the result of comparison with the conventional set anchor as shown in FIG. 10C shows that the conventional set anchor composed of four anchors was about 3 tons in a loam layer having an N value of about 3. It was confirmed that the anchor of the present invention composed of three steel rods provided about 6 tons of resistance on the ground having an N value of about 2 (see the graph of FIG. 7). ).

FIGS. 8 and 9 show the structure of another embodiment of the anchor assembly according to the present invention. In the embodiment shown in FIG. 8, the head fixing device 30 is a triangular grooved steel. Triangle head fixture 30
A plurality of holding plates 33 are welded to the groove portions for reinforcement. 8B is a cross section taken along line 3-3 in FIG. 8A, FIG. 8C is a cross section taken along line 4-4 in FIG. 8A, and FIG. It is 5-5 section of A). The lower plate 22 placed below the triangular head fixture 30 is a triangular plate having the same contour as the head fixture 30.
Four steel rods 20 are fixed so as to penetrate near and at the center of each apex of the triangle of the head fixing device 30, the outer three are of the same length, and the central one is for fixing the wire. It is. As shown in FIGS. 8B to 8D, the steel rods 20 near each vertex are fixed by penetrating the channel steel, and the central steel rod 20 is
As shown in FIG. 8 (C), it is fixed by penetrating through a reinforcing tube 23 which is a spacer sandwiched between the lower plate 22 and the upper plate 25.

Preferably, a steel rod 2 fixed near each vertex
0 is a winged void tube 2 buried under the head fixture 30.
7. The winged void tube 27 is a winged reinforcing tube, and its top view and front view are shown in FIG.
A wing portion 27 is provided on the outer surface of the tube portion 29. When the grout is filled, the gap between the steel bar 20 and the inner wall of the winged void tube 27 is also filled with the grout so that they are firmly integrated. The use of the winged void tube 27 can further increase the earth pressure resistance. In addition, when installing the winged void pipe 27 at the time of construction, since the hole is driven after the hole is drilled to some extent, the hole wall also serves to prevent the hole wall from collapsing when the hole is further excavated. Therefore, it is preferable to use the winged void pipe especially when the ground is easily collapsed and a predetermined resistance cannot be obtained.

In the embodiment shown in FIG. 9, the head fixing device 30 is formed by crossing box steels in a cross shape. FIG. 9B is a cross-sectional view taken along line 6-6 of FIG.
(C) is a 7-7 cross section of FIG. 9 (A). Four lower plates 22 are placed, and L-shaped portions 22a are attached vertically from two sides of the triangle of each lower plate 22. The L-shaped portions 22a are bolted to the side surfaces of the cross-shaped head fixing device 30 with bolts 35. It is fixed with a nut 36. Five steel rods 20 are respectively penetrated and fixed near and at the four ends of the cross-shaped head fixture 30. Preferably, as shown in FIG. 9B, the steel rod fixed near the end penetrates the winged void tube 27 similarly to the example described with reference to FIG. In this way, a set anchor body having an extremely strong structure is obtained. The winged void tube is shown in FIGS.
Can also be used in the embodiment shown in FIG.

[0031]

According to the present invention, there is provided an anchor for fixing a rock fall prevention net or the like, in which a plurality of steel rod heads are firmly fixed to the ground with a head fixing tool and grout. did. As a result, an anchor that can exhibit extremely large resistance as compared with a conventional anchor has been realized.

Further, the anchor assembly according to the present invention is constructed so that all parts can be carried by one worker in consideration of construction on a steep slope. In addition, drilling can be performed by a manual machine such as a rock drill, and the assembling of parts is easy, and after the assembling, the work for filling grout into the head fixing box and its surroundings can be sufficiently performed alone. As described above, the set anchor body of the present invention is extremely easy to construct. In this regard, the conventional driving-type anchor requires special equipment, so that it is often difficult to work on a slope or the like.

The steel rod in the anchor assembly of the present invention is preferably a steel rod having an anticorrosive coating such as hot-dip galvanized, and further, its surroundings are covered with grout. An anticorrosion effect is obtained. Therefore, it has high durability in which the performance of the most important anchor in a rock fall prevention net or the like is guaranteed for a long time.

Further, the anchor body of the present invention has little influence on the ground because its deformation is minute. In this regard,
Since the conventional anchor has a large deformation, a phenomenon such as accumulation of rainwater due to a gap between the ground and the anchor occurs, and inconveniences such as a decrease in ground resistance around the anchor are likely to occur. Such an inconvenience does not occur in the anchor set of the present invention.

A preferred application of the anchor assembly of the present invention is to use it as an anchor for earth and sand applied to high places or steep slopes. In other words, it can be used for fixing unstable rocks, combining with high energy absorption type rock fall prevention nets and fences, or as a small anchor used for temporary construction.

As described above, the anchor assembly according to the present invention provides a very useful technique for preventing falling rocks, avalanches, etc. for ensuring safety.

[Brief description of the drawings]

FIG. 1 is a view showing a structure of a set anchor body installed on a slope according to the present invention, wherein (A) is a top view of the set anchor body, and (B) is a cross-sectional view taken along a line 1-1 in the top view. is there.

FIG. 2 is a cross-sectional view taken along a line 2-2 in the top view of FIG.

FIG. 3 is a perspective view of a head fixing box used for the set anchor body of the present invention.

FIG. 4 is a view showing an example of a construction procedure for installing the set anchor body of the present invention on a slope on the ground.

FIG. 5 is a configuration diagram schematically showing an example in which the set anchor body according to the present invention is applied to installation of a rockfall prevention net.

FIG. 6 is a schematic view for explaining the operation of the anchor set according to the present invention.

FIG. 7 is a graph showing the results of measuring the displacement amount of the anchor head with respect to the load in the conventional standard anchor and the assembled anchor body of the present invention.

8A and 8B are diagrams showing another example of the structure of the anchor set according to the present invention, wherein FIG. 8A is a top view of the anchor set, and FIG.
Is a 3-3 cross-sectional view in the top view, (C) is a 4-4 cross-sectional view in the top view, (D) is a 5-5 cross-sectional view in the top view, and (E) is It is the top view and front view of a winged void tube.

FIG. 9 is a view showing the structure of still another example of the braided anchor body according to the present invention, wherein (A) is a top view of the braided anchor body,
FIG. 6B is a cross-sectional view taken along the line 6-6 in the top view, and FIG.
Fig. 7 is a sectional view taken along the line 7-7 in the top view.

10A and 10B are diagrams schematically illustrating an example of a conventional anchor, in which FIG. 10A is an anchor used when a slope or the like is rock, and FIGS. Anchor used for soft earth and sand.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 hole 12 Embedded part of head fixed box 20 Steel rod 21 Lower nut 22 Lower plate 23 Reinforcement tube 25 Upper plate 26 Upper nut 27 Void tube with wing 28 Feather 29 Tube part 30 Head fixture 31 Steel rod through hole 32 Air Removal hole 33 Holding plate 35 Bolt 36 Nut 40, 42 Grout 50 Set anchor body 60 Wire rope 70 Rock 100 Ground 110 Expansion bolt 120 Anchor with blade 122 Blade 123, 133 Rope mounting part 130 Assembly anchor 132 Anchor connection tool

Claims (13)

[Claims] Claims: 1. An anchor installed in a rock mass to fix a rock fall prevention net or a rock fall prevention fence to a rock mass on a slope or a slope other than a bedrock, wherein the rock mass has a single row, a triangle or a cross shape. A plurality of steel rods respectively inserted into a plurality of holes arranged in a plurality, and a plurality of steel rod through-holes through which respective heads of the plurality of steel rods respectively penetrate. A fixing device, a head fixing device installed in a head fixing device buried portion provided in the ground, a gap between each of the plurality of steel rods and the ground, and the head fixing. An anchor assembly comprising: a tool and a grout filled in a gap between the tool and the ground. 2. The method according to claim 2, wherein the head fixing member is a hollow box or groove having a substantially rectangular parallelepiped shape, a substantially triangular shape or a substantially cross shape, and the inside of the box or the groove is also filled with grout. The set anchor body of claim 1, wherein: 3. The anchor assembly according to claim 1, wherein the head fixing member is formed by providing the plurality of steel rod through holes in an H-shaped steel, a square steel pipe, and a grooved steel. 4. The anchor assembly according to claim 1, wherein at least one of the plurality of steel rods is relatively longer than the other steel rods. 5. The anchor assembly according to claim 1, wherein each of the plurality of steel rods is a steel rod having an anticorrosion coating. 6. The set anchor according to claim 1, wherein each of the plurality of steel bars is fixed by a plate and a nut below and above the head fixture. body. 7. The winged void tube driven into the ground below the head fixture and at least one of the plurality of steel bars penetrates. An anchor assembly according to any one of the preceding claims. 8. A construction method for installing an anchor for fixing a rockfall prevention net or a rockfall prevention fence on a slope or slope other than a bedrock, excavating a buried part for burying a head fixture, A plurality of holes arranged in a row, a triangle or a cross extending in a vertical direction or a slope direction from the bottom surface of the head fixing device embedded portion are excavated in the ground, and a plurality of steel bars are inserted into each of the plurality of holes. A head fixture is installed in the head fixture buried portion by penetrating each head of each of the plurality of steel rods, a gap between each of the plurality of steel rods and the ground, and A grout is filled in a gap between the head fixing device and the ground, and a method of constructing a set anchor body is provided. 9. A construction method for installing an anchor for fixing a rockfall prevention net or a rockfall prevention fence on a slope or slope other than a bedrock, excavating a buried portion for burying a head fixing device, After digging a plurality of holes arranged in a row, a triangle or a cross in the vertical direction or the slope direction from the bottom surface of the head fixture burying portion in the ground, filling each of the plurality of holes with grout, Each of the steel rods is inserted, and the head fixing tool is installed in the head fixing tool burying part by penetrating each head of each of the plurality of steel rods. A method for constructing a set anchor body, characterized by filling a gap with grout. 10. When the head fixing device is a substantially rectangular parallelepiped, substantially triangular or substantially cross-shaped hollow box or groove, grout is filled into the inside of the box or groove. The method for constructing an anchor assembly according to claim 8 or 9, wherein 11. A drilling method for drilling at least one of the plurality of holes relatively deeper than another hole, wherein the relatively deeply drilled hole has a steel rod relatively longer than the other steel rod. 11. The method according to claim 8, wherein the anchor is inserted. 12. The anchor assembly according to claim 8, wherein each of the plurality of steel bars is fixed by a plate and a nut below and above the head fixture. Construction method. 13. The construction of the anchor assembly according to claim 8, wherein when excavating the hole in the ground, a feathered void pipe is driven into an opening of the hole. Method.