JPH04221117A - Removal type anchoring - Google Patents

Abstract

PURPOSE:To draw out a tension member with low tension easily and quickly by keeping the tension member from being twisted to prevent a pulling-jump phenomenon. CONSTITUTION:A folded portion of an anchoring portion of a tension member 2 is stored in a loading body 1, and when the tension member 2 is drawn out of a dug hole, the end portion of the tension member 2 is grasped by a hanging jig. Subsequently, the loading body 1 is installed on the tension member 2 to form an anchor tendon, the anchor tendon is inserted in a dug hole, and a consolidation material is charged in a borehole anchoring portion. After the consolidation material expresses a designated strength, both end portions of the tension member 2 are pulled and tensed to be fixed. After that the end portions of the tension member 2 are pulled so that the tension member 2 is broken and removed. Thus, the work can be performed safely without twisting of the tension member 2 W.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a removable anchor construction method.

0002

[Prior art] As a construction method for removable anchors, the ninth
As shown in the figure, there is a method in which a tensile material b is folded back in a U-turn shape and attached to a bullet-shaped load-bearing body a, etc., and fixed in the ground. When removing the tensile material b in this method, a method is used in which one end of the tensile material b is pulled and pulled out.

0003

[Problem to be solved by the invention] The above-mentioned prior art includes:
The following problems exist. <A> When the tensile material b is pulled out, the tensile material b passes through the load-bearing body a, and therefore, severe twisting may occur in the tensile material b. Therefore, tensile material b
At the same time as exiting the drilling hole, untwisting occurs and the tensile material b
A phenomenon occurs in which the object becomes like a spiral spring and springs up to the top (the lifting source). In some cases, it can rise above the tip of the tow truck's boom, making it difficult for workers to be placed near the borehole during removal, and seriously interfering with other operations. Furthermore, when the tension material b jumps up, there is a possibility that the tension material b may fall due to the lifting jig coming off, making removal of the tension material b an extremely dangerous operation. moreover,
In cases where there are overhead wires above the building due to location conditions, or where there is limited space between buildings and adjacent buildings, it becomes impossible to remove the tensile material b using a tow truck, etc., resulting in major problems such as delays in the work process. becomes. <B> The conventional method of pulling out the tensile material B by passing it through the load-bearing body a, even if a tow truck is used, pulls out one tensile material B at a rate of 4 to 5 tf/
The tension of the book is required, and depending on the location where the tow truck is installed, the tow truck's capacity may be exceeded and the book may not be able to be pulled out. <C> As mentioned above, the pulling tension of tensile material b is 4 to 5 tf/
Since it is as large as a book, it is difficult to pull out a plurality of tension members b at once, and removal takes a considerable amount of time, which affects other operations.

0004

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to prevent the springing up phenomenon by pulling out the tensile material without twisting the tensile material. The purpose of the present invention is to provide a removable anchor construction method that can be easily and quickly pulled out with low tension. That is, in the present invention, the tensile material is folded back into a U-shape and installed on the load-bearing body attached to the tip of the anchor fixing length, and after tensioning and fixing by pulling both ends of the tensile material, the ends of the tensile material are This is a removable anchor construction method in which the tensile members are pulled and broken, and each broken tensile member is pulled out and removed. In addition, a rotatable rotating plate having a U-shaped surface on one side and a breaking blade on the other side is installed inside the load-bearing body attached to the tip of the anchor anchorage length, and the ,
The tensile material is folded back into a U-shape and placed inside the load-bearing body, and both ends of the tensile material are pulled to tighten and settle. Then, one end of the tensile material is pulled and the breaking blade of the rotating plate is inserted into the U-shaped folded portion of the tensile material. This is a removable anchor construction method in which the anchor is rotated to the side to break the tension member, and each broken tension member is pulled out and removed.

[0005]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. <A> Structure of the load-bearing body (FIGS. 5 and 6) The load-bearing body 1 is a hollow box that accommodates the folded portion of the fixed length portion of the tensile material 2. For example, as shown in Figures 5 and 6,
A side plate consisting of a U-shaped portion 11 and a straight portion 12 connecting both ends thereof, and two opposing plates 13 that close the upper and lower surfaces of the side plates are used. The load-bearing plate 1 is configured to be able to be divided into upper and lower parts, and insertion holes 14 for the tensile material 2 are provided near both ends of the side plate linear portions 12. An injection port 15 for the water stop material 3 is provided in the plate 13 that closes the upper and lower surfaces. The upper and lower load-bearing plates 1 can be integrated with bolts 16, as shown in FIG. Next, inside the load-bearing plate 1,
A rotary plate 4 having a shape as shown in FIG. 5 is housed with its central portion rotatably supported by a pin 41. The rotating plate 4 is composed of an arcuate U-shaped surface 42 and an acute-angled breaking blade 43 formed on the opposite side thereof. <B> Structure of the hanging jig (FIGS. 7 and 8) The hanging jig 5 grips the end of the tensile material 2 when pulling the tensile material 2 out of the drilled hole. For example, Figures 7 and 8
A structure like the one shown is possible. That is, in the hanging jig 5, a wedge hole 51 is appropriately opened in the axial direction of the cylindrical member, a wedge 52 is housed in the wedge hole 51, and an insertion hole 53 for the tensile material 2 is opened in the head of the wedge 52. It is constructed by arranging a presser plate 54. The holding plate 54 is fixed to the hanging jig 5 by tightening bolts 55, and by tightening the tightening bolts 55, the holding plate 54 inserts the wedge 52 into the wedge hole 5.
It can be pushed into 1. Moreover, a hook hook 56 for connecting a tow truck hook is attached to a symmetrical position on the circumferential surface of the hanging jig 5. <C> Attaching the tensile material (FIGS. 5 and 6) The tensile material 2 used is an unbonded type in which a PC steel wire 21 is covered with a sheath 22. This tensile material 2 is bent into a U-shape, and the sheath 22 at the bent portion is removed to expose the PC steel wire 21. Then, this exposed part is stored along the U-shaped part 11 in one of the divided load-bearing plates 1,
Both ends are exposed through the insertion hole 14, and the other load-bearing plate 1 is combined with the bolt 16. At this time, the rotary plate 4 is positioned so that the U-shaped surface 42 side contacts the PC steel wire 21. Further, in order to prevent the rotary plate 4 from becoming stuck due to penetration of the anchor paste, water and a water stop material 3 such as urethane are injected through the injection port 15 to protect the rotary plate 4. <D> Fixing the anchor (Fig. 1) After attaching the load-bearing body 1 to the tension member 2 as described above to construct the anchor don, insert the anchor don into a hole drilled in the ground, and place the consolidation material into the hole. Fill the internal fixing length. Then, after a predetermined strength is developed in the consolidation material, tension force is introduced into the tensile material 2. When tension is applied, both ends of the tensile member 2 are pulled at the same time, as shown in FIG. 1, so the load is transmitted in the same direction and the rotary plate 4 does not move. Therefore, P
The exposed portion of the C steel wire 21 remains in contact with the U-shaped surface 42 of the rotating plate 4, and sufficient anchor strength can be obtained. <E> Breaking of tensile material (Figure 2) After using the anchor, the tensile material 2 is broken in order to be removed. First, using a jack or the like, one end of the tension member 2 is pulled as shown in FIG. This causes the tensile material 2 to stretch. Then, due to the frictional force between the PC steel wire 21 and the U-shaped surface 42 of the rotary plate 4, the rotary plate 4 rotates, and the breaking blade 43
It comes into contact with the C steel wire 21. Therefore, the point of contact between the PC steel wire 21 and the rotating plate 4 changes from a plane to a point, and the breaking blade 43 bites into the PC steel wire 21 and breaks it. At this time, if one anchor donton is composed of a plurality of tension members 2, the extra length at the end of each tension member 2 should be set at 5 cm to distinguish between already cut and uncut ones. Possible options are to shift them by degrees or to separate them by color by attaching colored tape or the like. As described above, the tensile material 2
Perform breaking work on all the pieces. The jacking pressure at the time of breakage is approximately 16 to 20tf/m2 when a PC steel wire with a diameter of 12.7m/m2 is used, so there is no fear of the jack, wedge, etc. flying off. <f> Removal of the fixing device (
Figure 3) After breaking the tension member 2, as shown in Figure 3, pull the tension member 2b on the side that was not tensioned all at once, drop the wedge 61, and fix the anchor head, anchor plate, pedestal, etc. 6 will be removed. Note that the wedge 61 of the tensile member 2a on the tensile side has already fallen off when it is pulled to break. <G> Pulling out the tensile material (FIG. 4) A hanging jig 5 is attached to the exposed end of the PC steel wire 21 of each broken tensile material 2. As shown in FIG. 4, a plurality of PC steel wires 21 are passed through the hanging jig 5 and the holding plate 54, and
After tightening, tighten the tightening bolts 55 of the holding plate 54,
To prevent the wedge 52 from lifting up. In this manner, the hanging jig 5 can be easily attached, and the holding plate 54 can prevent the wedge 52 from lifting up or falling off. On the other hand, two wires 7 are connected to the hook 7 of a tow truck etc. via a hanging ring 71.
2 are connected, and a hook 73 is connected to the lower end of each wire 72. This hook 73 is connected to each hook hook 56 of the lifting jig 5, and the lifting can be carried out safely at two points. Then, the lifting jig 5 is pulled up by a tow truck or the like, and the tension member 2 is pulled out and removed from the hole. The pulling force at this time is 4
00 to 500 kgf/piece, which is very small compared to conventional methods, so it is possible to handle multiple (6 to 8) tensile materials 2 at a time.
can be pulled out. In addition, when pulling out, 5 to 6
It is preferable to bind the tensile material 2 every m with a wire to prevent variations. After the pulled tensile material 2 is divided and accumulated,
Carry it out.

[0006]

[Effects of the Present Invention] Since the present invention is as explained above, the following effects can be obtained. <A> Since the tensile material is pulled out after being broken, the tensile material does not pass through the load-bearing body, and twisting as in the conventional method does not occur. Therefore, it is possible to prevent the tensile material from jumping up, allowing work to be carried out safely near the hole opening, and not interfering with other operations. Furthermore, it is possible to prevent the tensile material from falling due to the jig coming off, and the work can be carried out safely. Furthermore, there is no impact on neighboring areas, overhead lines, etc., and construction can be carried out regardless of location conditions. <B> Since each broken tensile member is pulled out after breaking the tensile member, the tensile force is 400 to 500 kgf/piece, which is extremely small compared to the conventional method. Therefore, the tow truck can be made smaller and more economical. Furthermore, it is possible to pull out a plurality of tension members (6 to 8) at a time, which significantly improves construction efficiency, making it possible to significantly shorten the construction period. <C> Since there is no twisting of the tensile material and deformation is prevented, it is possible to save labor and improve the efficiency of the accumulation and disposal of the tensile material after removal, and it is also possible to perform construction in narrow spaces. <D> When the tensile member is tensioned, the U-shaped surface of the rotary plate and the tension member are in contact with each other, so that the tensioning force of the anchor can be sufficiently obtained as in the conventional case. <E> Since the tensile material is easily broken by the sharp breaking blade, the tensile material can be broken with low tension and is safe.

[Brief explanation of the drawing]

[Figure 1] Explanatory diagram of the state where tension force is introduced into the tensile material

[Figure 2
】Explanatory diagram showing the breaking work of tensile material

[Figure 3] Explanatory diagram of fixing tool removal work

[Figure 4] Explanatory diagram of tensile material pulling work

[Figure 5] Perspective view of load-bearing body

[Figure 6] Plan view of load-bearing body

[Figure 7] Plan view of the hanging jig

[Figure 8] Side view of the hanging jig

Claims (2)

[Claims] [Claim 1] A tensile material is folded back into a U-shape and installed on the load-bearing body attached to the tip of the anchor fixing length, and both ends of the tension material are pulled to tighten and fix the material, and then the ends of the tension material are pulled. This is a removable anchor method in which the tensile members are broken by using the same method, and each broken tensile member is pulled out and removed. 2. A rotatable rotating plate having a U-shaped surface on one side and a breaking blade on the other side is installed in a load-bearing body attached to the tip of the anchor anchorage length, and the U-shaped surface of the rotating plate is
Fold the tensile material into a U-shape and place it inside the load-carrying body, pull both ends of the tensile material until it is taut, and then pull one end of the tensile material to insert the breaking blade of the rotary plate into the tensile material. A removable anchor construction method in which the tension member is rotated toward the U-shaped folded part of the frame, the tension member is broken, and each broken tension member is pulled out and removed.