JP3594922B2 - Anchor method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchoring method for anchoring anchor cables (generally called tendons), such as stranded PC steel wires, to anchor plates in hill work, slope stabilization work, or structural stability work. It is.
[0002]
[Prior art]
In anchoring work, etc., anchor cables are inserted into holes drilled deep in the ground and fixed with grout material, and the ends of the anchor cables are fixed to the surface anchor plate with wedges, bolts and nuts. ing.
[0003]
The wedge fixing method described above fixes the anchor cable to the anchor plate by sandwiching the split wedge at the tip of the anchor cable and fitting the wedge into a hole of an anchor head fixed to the anchor plate. The wedge fixing method can freely fix a position different from the expected position according to the situation at the place if the user is nervous for work on site, and the workability is good.
[0004]
In addition, the screw type fixing method is generally called an apartment type, in which a screw type fixing device is fixed to the end of an anchor cable in advance by crimping at a factory, and the screw type fixing device is inserted into a through hole of an anchor plate. The anchor cable is fixed to the anchor plate by inserting the fixing cable and screwing the fixing nut. This condominium type is easy to re-tension the anchor cable and is excellent in terms of maintenance.
[0005]
[Problems to be solved by the invention]
However, the former wedge fixing method has the following problems.
(A) Once anchored, the anchor cable is scratched by wedges.
(B) The wedge easily slips due to rust.
(C) If there is no more than a certain amount of tension, it is difficult to re-tension the anchor cable with a tension device such as a jack.
(D) The adjustment margin is limited even for a ring type in which the outer periphery of the anchor head is threaded, and it is generally difficult to maintain and maintain the work after installation (after fixing).
[0006]
Further, the latter screw type fixing system has the following problems.
(A) It is difficult to perform on-site crimping of the screw fixing device to the anchor cable, and the screw fixing device must be fixed to the anchor cable at a factory. For this reason, when the length of the previously manufactured anchor cable is different from the actual effective length after construction, it is necessary to refill and raise the anchor plate, which is troublesome and impairs the appearance.
(B) The strength of the fixing tool expected at the beginning cannot be obtained due to the addition or the like.
(C) The anticorrosion performance and anticorrosion structure do not meet the specifications.
(D) When the lengths of the anchor cables extending from the load bearing bodies buried in the ground to the ground surface are different from each other, a uniform load is applied to a plurality of anchor cables having different lengths. It is difficult.
[0007]
An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to be able to securely and easily attach a screw-type fixing device to an anchor cable at a work site, and have different lengths. An object of the present invention is to provide an anchor construction method in which a uniform load is applied to an anchor cable to perform ideal tension management.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a plurality of anchor cables having different lengths are inserted through a cylindrical anchor screw fixing device, and formed on the outer periphery of the anchor screw fixing device. In the anchor method of anchoring the anchor cable to the anchor plate engaging with the anchor nut by screwing the anchor nut to the screw part and tightening it,
Said anchor cable in a state of being inserted into the threaded fixing member for anchoring, they lengths of different anchor cable perform tensioning work for adjusting the load of the uniform at any load, while keeping this state, the anchor cable And a cylindrical screw-type fixing device for an anchor are fixed with a binder, and a fixing nut screwed to the screw-type fixing device for an anchor is tightened to fix the anchor cable to the anchor plate.
[0009]
According to this method, the anchor cable is fixed to the anchor screw fixing device at the work site, so that the anchor screw fixing device that can be freely mounted at the optimum position of the anchor cable can be attached. Therefore, unlike the conventional screw type fixing method, no additional extension or raising of the anchor plate is required, and the anchor cable can be fixed efficiently and quickly and accurately without any trouble, and the appearance is not spoiled. .
In addition, since the tensioning work for adjusting the uniform load of the anchor cables having different lengths with an arbitrary load is performed before the fixing, when finally fixing the anchor cables to the anchor plate by tightening with the fixing nut, A uniform load can be applied to each anchor cable having a different length, and ideal tension management can be performed.
[0010]
The invention according to claim 2 is the anchor method according to claim 1,
For tensioning work for adjusting the anchor cables having different lengths to an equal load with an arbitrary load, a plurality of pooling head blocks are interposed between the pooling head blocks, and the anchor is provided between the pooling head blocks. A differential elastic body spaced apart along the length direction of the cable, and an anchor cable fixing tool for fixing the anchor cable to any one of the plurality of pooling head blocks according to its length; A jack that moves a plurality of pooling head blocks with the differential elastic body interposed therebetween and applies a tension to each anchor cable fixed to the pooling head block. It is characterized by.
[0011]
With this means, it is possible to arrange the anchor cables having different lengths to have a uniform load by using a differential tensioning device having a simple configuration, so that the cost can be reduced without difficulty and the configuration is simplified. Field work becomes easier.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a state in which a permanent anchor body A is buried in the ground G underground. The anchor body A is formed by inserting the first to third load bearing members 1, 2, 3 and the first to third anchor cables 10, 20, 30 into the anchor holes Ga excavated in the ground G, and then inserting the anchor holes A into the anchor holes Ga. After filling grout material M such as mortar in Ga and hardening, as described later, each anchor cable 10, 20, 30 is tensioned to be fixed to ground G via anchor plate 50 (FIG. 5). reference).
[0013]
The load-bearing bodies 1, 2, and 3 are screwed to an axial force transmitting member (not shown) made of a steel screw bar or the like and arranged at equal intervals from the underground side. The underground ends of the anchor cables 10, 20, 30 are engaged.
[0014]
In this case, two anchor cables are engaged with one load-bearing body 1, 2, 3. The anchor cables 10, 20, 30 use so-called unbonded strands in which a PC strand is passed through a sheath tube (not shown). The ends of the anchor cables 10, 20, 30 are pulled out to the ground. The drawn end penetrates the anchor plate 50 set on the ground surface.
[0015]
Then, the ends of the anchor cables 10, 20, 30 pulled out to the ground surface are washed to remove foreign substances such as moisture, grease, cement, etc. adhering to the surface thereof. In the inserted state, the cables are tensioned using the differential tensioning device 70 in order to apply a uniform load to the anchor cables having different lengths (see FIG. 2).
[0016]
Here, the screw fixing device for anchor 60 has an insertion hole 61 at the center, a male screw (screw portion) 62 on the outer peripheral surface, and an injection hole 63 on the side of the lower end. ing. The insertion holes 61 allow the anchor cables 10, 20, and 30 to pass therethrough. The insertion holes 61 have a tapered shape that narrows from the upper end to the lower end, and the lower part of the inner surface is provided with relatively large irregularities by machining. It has a rough surface. The lower end of the insertion hole 61 is chamfered to facilitate insertion of the anchor cables 10, 20, 30.
[0017]
The male screw 62 is for screwing the fixing nut 80 shown in FIGS. 2 and 3, and is formed as a trapezoidal screw by, for example, machining. The injection hole 63 is for injecting the epoxy resin 90 into the insertion hole 61 as shown in FIG. 3 (described later in detail with reference to FIG. 5 and the like).
[0018]
Next, the distal ends of the anchor cables 10, 20, 30 are tensioned by the differential tensioning device 70. The differential tensioning device 70 has the following configuration.
[0019]
That is, the differential tensioning device 70 includes a jack 71 and a differential pooling head 72 set at the tip end of the jack 71. Differential pooling heads 72 are provided with a plurality (three in this case) of pooling head blocks 73 corresponding to the number of load-bearing bodies, and anchor cables 10 interposed between the pooling head blocks 73 and between the pulling head blocks 73. The differential elastic bodies 74 spaced along the length direction of the 20, 30 and the anchor cables 10, 20, 30 are connected to any one of the plurality of pooling head blocks 73 according to their lengths. And a fixed wedge 75.
[0020]
The pooling head blocks 73 are stacked from the jack 71 side in the tensioning direction (direction away from the ground surface), and the first to third pooling head blocks 73a, 73b, and 73c are arranged in this order. An anchor cable 10 extending from the load-bearing body 1 set deep in the ground is fixed to the first pooling head block 73a, and set to an intermediate position in the ground to the second pooling head block 73b. An anchor cable 20 extending from the load bearing member 2 is fixed, and an anchor cable 30 extending from the load bearing member 3 set on the side closest to the underground surface is fixed to the first pooling head block 73a.
[0021]
Further, the pooling head blocks 73 are disc-shaped rigid bodies, through which the anchor cables 10, 20, 30 are passed, and wedge holes for fixing the anchor cables 10, 20, 30 via the wedges 75, are formed. I have. The wedge holes are formed in such a number that at least all the anchor cables 10, 20, 30 are passed therethrough. In addition, annular convex portions 76 are formed on the facing surfaces of the pooling head block 73 so as to face each other. An annular differential elastic body 74 is fitted into the outer peripheral side concave portion 77 of the annular convex portion 76, thereby forming a predetermined interval between the pooling head blocks 73a, 73b, 73c. As the differential elastic body 74, for example, a Chelast elastic body made of high-density urethane foam and having a high elastic return force is preferably used. The differential elastic body 74 between the first pooling head block 73a and the second pooling head block 73b is the first differential elastic body 74a, the second pooling head block 73b and the third elastic body 74b. The one between the pulling head block 73c and the pulling head block 73c is a second differential elastic body 74b.
[0022]
According to the differential tension device 70 having the above-described configuration, the distal ends of the anchor cables 10, 20, 30 are pulled through the chair 100 interposed between the differential tension device 70 and the anchor plate. The first, second and third anchor cables 10, 20, and 30 can be simultaneously and simultaneously tensioned by applying a tension to the first, second and third anchor cables 10, 20, and 30. Then, in the initial stage of the tension, the tension of the jack 71 is directly transmitted to the first anchor cable 10, transmitted to the second anchor cable 20 via the first differential elastic body 74 a, and It is transmitted to the cable 30 via the first and second elastic members 74a and 74b for differential. Due to the transmission of the tension by the jack 71, each of the differential elastic bodies 74a and 74b is elastically deformed and compressed, and when a stronger tension is applied, the pooling head blocks 73 come into contact with each other. That is, the annular convex portions 76 of the respective pooling head blocks 73 come into contact with each other. This point is the differential end point. This makes it possible to correct the difference in elongation according to the length of each of the anchor cables 10, 20, 30 and to make the loads applied to the load-bearing bodies 1, 2, 3 uniform at the time of the set load.
[0023]
As described above, after the anchor cables 10, 20, 30 are given predetermined tensions by the differential tensioning device 70, the temporary fixing plate 78 attached to the differential tensioning device 70 is maintained so as to maintain the tensioned state. Then, the anchor cables 10, 20, 30 are temporarily fixed (see FIG. 3).
That is, the split wedges 101 are provided so as to sandwich each of the anchor cables 10, 20, and 30 from the left and right sides, and the split wedges 101 are provided as they are on the upper surface of the chair 100. 78a.
After the anchor cables 10, 20, and 30 are temporarily fixed to the temporary fixing plate 78, the differential tensioning device 70 such as the jack 71 may be removed as necessary.
[0024]
Next, epoxy resin 90 is injected between the anchor screw fixing device 60 and the anchor cables 10, 20, 30 to fix the anchor cables 10, 20, 30 to the anchor screw fixing device (see FIG. 3). .
At this time, in order to prevent the epoxy resin 90 from leaking by closing the portion corresponding to the lower end of the screw fixing device 1 for the anchor cable that can be freely attached at a predetermined mounting position, as shown in FIG. It is preferable to fill gaps between the steel wires of the cables 10, 20, 30.
[0025]
In addition, the hardening of the epoxy resin 90 injected into the screw type fixing device 60 for the anchor is promoted, and the work is performed except for bad conditions such as outdoor rain, freezing, and low temperature, which hinder the solidified adhesion of the epoxy resin 90. For the purpose of improving and stabilizing the conditions, it is also preferable to heat the outer periphery of the anchor screw fixing device 60 with a heater such as an electric heater.
[0026]
After the completion of the above-mentioned operation or in parallel with the above-mentioned operation, as shown in FIG. 3, an epoxy resin 90 obtained by mixing an epoxy compound, a curing agent, and fibers such as glass fibers at a predetermined ratio is heated to the outer periphery. The anchor screw fixing device 60 is press-filled from the injection hole 63 to the upper portion of the insertion hole 61 in the anchor screw fixing device 60 through the pipe 113 by the caulking gun 112 or the like. As the epoxy resin 90, as described above, a mixture of an epoxy compound, a curing agent, and fibers such as glass fiber or carbon fiber is usually used, but an epoxy resin into which fibers such as glass fibers are not mixed, or Other consolidating agents can be used.
[0027]
Next, as shown in FIG. 4, a back tube 115 is driven in to prevent corrosion at the opening end of the anchor hole Ga, and the end is stopped with a water stopping material 116 such as epoxy resin or hot melt.
[0028]
After completion of the above operation, as shown in FIG. 4, the fixing nut 80 is tightened to the anchor screw type fixing device 60 without swinging, or the fixing is performed so that a stronger tension is applied to the anchor cables 10, 20, 30. The nut 80 is further tightened to fix the anchor cables 10, 20, 30 to the anchor plate 50. Note that the anchor cable protruding outward from the anchor screw fixing device 60 is cut as necessary.
[0029]
Thereafter, as shown in FIG. 5, a head cap 120 is attached to the anchor plate 50 so as to cover the exposed portion of the anchor screw fixing device 60 and the fixing nut 80. The fixing work is completed by filling 121.
[0030]
Although six anchor cables (PC steel stranded wires) 10, 20, and 30 are used in the drawing (only three are shown in FIG. 1 except for FIG. 1), use of the anchor cables 10, 20, and 30 is not shown. The number is arbitrary, and may be more or less than six.
[0031]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the anchor cable is fixed to the anchor screw anchor at the work site, the anchor screw can be freely mounted at the optimum position of the anchor cable. A tool can be attached. Therefore, unlike the conventional screw type fixing method, no additional extension or raising of the anchor plate is required, and the anchor cable can be fixed efficiently and quickly and accurately without any trouble, and the appearance is not spoiled. .
In addition, since the tensioning work for adjusting the uniform load of the anchor cables having different lengths with an arbitrary load is performed before the fixing, when finally fixing the anchor cables to the anchor plate by tightening with the fixing nut, A uniform load can be applied to each anchor cable having a different length, and ideal tension management can be performed.
[0032]
According to the second aspect of the present invention, it is possible to arrange the anchor cables having different lengths to have a uniform load by using the differential tensioning device having a simple configuration. Is simpler, the work on site becomes easier.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of one process for explaining an embodiment of an anchor method according to the present invention.
FIG. 2 is a cross-sectional view of one process for explaining an embodiment of the anchoring method according to the present invention.
FIG. 3 is a cross-sectional view of one step for explaining an embodiment of the anchoring method according to the present invention.
FIG. 4 is a cross-sectional view of one step for explaining an embodiment of the anchoring method according to the present invention.
FIG. 5 is a cross-sectional view of one step for explaining an embodiment of the anchoring method according to the present invention.
[Explanation of symbols]
1, 2, 3, load-bearing body 10, 20, 30 Anchor cable 50 Anchor plate 60 Anchor fixing device 61 for anchor 61 Insertion hole 62 Male screw (screw part)
70 Differential tensioning device 71 Jack 72 Differential pulling head 73 (73a, 73b, 73c) Pulling head 74 (74a, 74b) Differential elastic body 75 Wedge 78 Temporary fixing plate 90 Epoxy resin

Claims (2)

A plurality of anchor cables having different lengths are inserted through a cylindrical anchor screw fixing device, and a fixing nut is screwed onto a screw portion formed on the outer periphery of the anchor screw fixing device to tighten the anchor cable. In the anchor method of anchoring the cable to the anchor plate engaging the anchor nut,
Said anchor cable in a state of being inserted into the threaded fixing member for anchoring, they lengths of different anchor cable perform tensioning work for adjusting the load of the uniform at any load, while keeping this state, the anchor cable And fixing the anchor cable with the anchor plate by fastening the anchor nut screwed onto the anchor screw fixing device and the cylindrical screw fixing device for the anchor with a binder, and fixing the anchor cable to the anchor plate. . In the anchor method according to claim 1,
For tensioning work for adjusting the anchor cables having different lengths to an equal load with an arbitrary load, a plurality of pooling head blocks are interposed between the pooling head blocks, and the anchor is provided between the pooling head blocks. A differential elastic body spaced apart along the length direction of the cable, and an anchor cable fixing tool for fixing the anchor cable to any one of the plurality of pooling head blocks according to its length; A jack that moves a plurality of pooling head blocks with the differential elastic body interposed therebetween and applies a tension to each anchor cable fixed to the pooling head block. An anchor method characterized by the following.

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