JP5886643B2 - Large-capacity anchor method - Google Patents

Description

  The present invention relates to a large-capacity anchor method used for a large structure such as a concrete dam.

  Conventionally, a structure may be fixed to the ground using a ground anchor in order to prevent the structure from falling or sliding due to an external force acting on the structure. In that case, the structure can be stabilized by fixing the tip of the ground anchor to the ground, applying tension to the ground anchor, and fixing the upper end of the ground anchor to the structure. As inventions related to ground anchors, there are inventions described in Patent Documents 1 and 2, for example.

  Patent Document 1 describes a ground uncurtain dong that uses a plurality of tendons configured by bundling a plurality of tendons in an anchor installation hole in a concrete structure. An anchor body length portion that is integrally fixed to the bottom side region of the anchor installation hole, and a free length portion that is continuous to the anchor body length portion and whose ground surface side is fixed to a fixing portion of the anchor head, And a protective body covering the outer peripheral part of each tendon or the outer peripheral part of all tendons, and the protective body has a length of 1/30 to 1/20 of the total length of the tendon. ing.

  Patent Document 2 describes an anchor insertion method in which an anchor is inserted into an anchor hole formed downward in the ground. A pulley having a guide groove capable of guiding the anchor around it is rotatably provided, the anchor is guided by the guide groove of the pulley, and the pulley is rotated in this state, thereby inserting the anchor into the anchor hole.

Patent No. 4519083 JP 2010-163819 A

  When ground anchors are used to prevent overturning or sliding of structures for the purpose of improving the stability of large structures such as concrete dams or seismic reinforcement (see Fig. 7), the anchors have high durability. Desired. In particular, in the case of a large structure, the anchor may have a large capacity (design anchor force is several hundred tons or more) and the anchor length may be long (50 m or more).

  As a ground anchor having excellent durability, an anchor having an anchor body in which a bundle of a plurality of PC steel materials is covered with capsules and filled with cement grout is considered to be effective, but this anchor has a large capacity. When the design anchor force is increased, the number of PC steel materials that are tensile materials increases, and the diameter of the capsule increases, which makes it difficult to carry and to insert into the boring hole.

  In addition, in the anchor body covered with the capsule, there are two possible construction methods for filling the cement grout in the capsule before the anchor is inserted into the boring hole and after the insertion.

  After inserting the anchor into the boring hole, when filling the capsule with grout in the boring hole, multiple hoses such as injection hose and exhaust hose must be attached to the anchor, and the filling state of the anchor body is confirmed Difficult to do.

  On the other hand, when the cement grout is filled before the anchor is inserted into the borehole, it is necessary to secure a work yard near the anchor construction position. Further, in the insertion operation, the anchor body in which the cement grout is consolidated in the capsule and becomes a pencil shape must be carefully lifted and inserted so as not to be damaged.

  In the case of the invention described in Patent Document 1 described above, a combination of a plurality of tendons is used as one ground uncurtain don. For example, three tendons including seven tendons can be combined into one ground uncurtain don. In this case, although transportation is relatively easy, the number of tendons used for one tendon cannot be increased so much.

The present invention is intended to solve the above-described problems in the prior art, and in an unprecedented large-capacity anchor, it is easy to carry an an curtain curtain and insert it into a boring hole. The purpose is to provide a large-capacity anchor method that can maintain a stable arrangement

  In the present invention, an anchor body portion of a tensile material is inserted into a capsule to form an anchor body unit in a capsule unit, and a plurality of the capsules are bundled and fixed, and after filling each grout with a grout, The large-capacity anchor construction method is characterized in that the boring hole is inserted and then grout is filled into the boring hole.

  By covering the tensile material with capsules and making them into capsules, the arrangement of the tensile materials in each capsule is maintained in an appropriate state. An anchor configured by bundling a plurality of anchor body units each having an anchor body portion of a tensile material inserted into each capsule can easily obtain a design anchor force having a larger capacity than a conventional anchor.

  If the grout filling operation in the capsule is performed before being inserted into the boring hole, it is not necessary to install many long grout injection hoses for each capsule, and the grout filling operation in the capsule is easy and the working efficiency is improved. Moreover, the filling condition in each capsule of an anchor body can be confirmed reliably.

  Each capsule is filled with grout, and then inserted into the borehole while maintaining the arrangement of a plurality of anchor body units, and the bore is filled into the borehole through the grout injection hose attached to the uncurtain don.

  The capsule here is, for example, a corrugated sheath, and any type can be used as long as it can cover a tensile material and can further enhance the anticorrosion property of an an Curtain don.

  The anchor unit of the capsule unit in the present invention is carried into the construction site while being wound around a drum-shaped winding frame, and is supported by an anchor unit fixing frame supported by an insertion device installed on the ground part of the construction site. The anchor unit of the capsule unit is pulled out from the take-up frame and fixed in a plurality of vertical directions. In this state, each capsule is filled with grout and inserted into the boring hole.

  The anchor body unit is wound around a drum-shaped winding frame to facilitate the work of transporting the long uncurtain dong.

  An insertion device for an uncurtain dong is installed on the ground part of the construction site, and an anchor unit fixing frame for fixing a plurality of capsules is supported on the insertion device. The tip of the anchor body unit is pulled out from the drum-shaped winding frame, and a plurality of anchor body units are vertically fixed to the fixing frame, and an ancillary don with an appropriate arrangement is assembled.

  Each anchor body unit bundled and fixed by a fixed frame is filled with grout, and then inserted into the borehole, and the arrangement of the anchor bodies is maintained in the borehole.

  It is desirable that 3 to 20 uncurtain dongs according to the present invention are inserted into one capsule, and 2 to 6 of the capsules are bundled.

  Since the tensile material is covered with the capsule, an appropriate arrangement can be maintained, and about 3 to 20 pieces can be inserted into one capsule. It is possible to easily construct a large-capacity anchor by bundling 2 to 6 capsules into which the anchor body portion of the tensile material is inserted, as compared with a conventional ground anchor.

  Further, the large-capacity anchor according to the present invention comprises an anchor body unit configured by inserting an anchor body portion of a tensile material into a capsule, and a plurality of the capsules are fixed together by a fixing frame that also serves as a positioning, The capsule is filled with grout.

  With the fixing frame, each capsule can be easily and reliably positioned and fixed in an appropriate arrangement. In addition, the arrangement of the anchor bodies can be reliably maintained even after being inserted into the boring hole and placing a grout in the boring hole.

  It is desirable that 3 to 20 anchor body portions of the tension member are inserted into one capsule, and 2 to 6 capsules are bundled.

  In addition, although the large capacity | capacitance anchor by this invention is intended for the anchor constructed downward in the perpendicular direction, it allows about ± 10 degrees in the vertical direction.

  Since this invention becomes the above structures, the following effects are acquired.

(1) By bundling a plurality of anchor body units formed by covering a tensile material with a capsule, an unprecedented large-capacity vertical anchor can be efficiently constructed.

(2) In a large-capacity anchor, after anchoring a plurality of anchor bodies formed by covering a tensile material with capsules, the anchors are filled and then filled with grout and then inserted into the boring holes. The proper arrangement of the PC steel forming the tendon can be maintained.

(3) In the conventional method, when the number of PC steel materials forming the uncurtain dong is large, it becomes very heavy and difficult to carry and insert. However, in the present invention, the tensile material is coated in capsule units. By doing so, transportation and insertion work can be performed efficiently.

(4) The tensile material is covered with a capsule to further improve the corrosion resistance.

(5) By performing the grout filling operation in each capsule before inserting it into the boring hole, the grout filling operation in the capsule can be easily performed, and the filling state can be surely confirmed, leading to improvement in the quality performance of the anchor.

(6) With the anchor unit fixing frame, each capsule can be easily positioned and fixed in an appropriate arrangement. Moreover, the arrangement of the anchor bodies can be reliably maintained even when the grout is inserted into the borehole after being inserted into the borehole.

FIG. 6 is a cross-sectional view of an uncurtain don when one embodiment of a large-capacity anchor according to the present invention is inserted and disposed in six capsules in which seven tension members are bundled. 1 is a perspective view schematically showing a state in which a capsule is fixed to an anchor unit fixing frame, showing an embodiment of a large-capacity anchor according to the present invention. It is sectional drawing which showed the example of the anchor structure which uses a capsule, (a) is the case of 1 capsule of a prior art example, (b) represents the case of the multiple capsule which concerns on this invention. It is the flowchart which showed the construction procedure example of the large capacity | capacitance anchor method concerning this invention. In the large-capacity anchor construction method according to the present invention, it is a schematic diagram showing an embodiment of an uncurtain don insertion device. It is explanatory drawing which showed schematically the construction procedure in FIG. It is the cross-sectional view which showed the example of ground anchor installation for reinforcing a concrete dam.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

〔Example〕
FIG. 1 shows a cross-sectional view of an embodiment of a large-capacity anchor 1 method according to the present invention. A bundle of seven tension members 3 is placed on a capsule 4 to form an anchor body unit 2. Six capsules 4 constituting the anchor body unit 2 are fixed using a spacer 6a and a fixing band 6b. A suspension wire 7 for suspending the large-capacity anchor 1 is provided at the center of the spacer 6a, and a hole through which the grout injection hose 8 is passed so as to sandwich the suspension wire 7 is provided.

  Examples of the capsule 4 include a corrugated sheath, and any type or material can be used as long as it can cover a bundle of a plurality of tension members 3 and can further enhance the corrosion resistance of the tension members 3. Absent.

  FIG. 2 schematically shows an anchor unit fixing frame 6 for fixing the anchor unit 2. The anchor unit fixing frame 6 is composed of a spacer 6a and a fixing band 6b. The capsule 4 is fitted into a recessed portion of the spacer 6a, and the fixing band 6b is wound around and fixed to the outer periphery of the capsule 4.

  Although FIG. 2 shows only one capsule 4, a plurality of capsules 4 are actually fixed. In addition to the shape shown in FIG. 2, the shape or the like is not limited as long as it is an anchor body fixing frame 6 in which the capsules 4 can be arranged at appropriate positions.

  FIG. 3 shows an example of an anchor structure using the capsule 4. FIG. 3A shows a case where nine PC steel materials 21 are inserted into one capsule 4. A part of the PC steel material 21 is covered with a sheath 22. In the case of FIG. 3A, a bundle of nine PC steel materials 21 is inserted into the capsule 4 and the grout 5 is injected into the capsule 4.

  In FIG. 3A, which is a conventional example, when the number of PC steel materials 21 is increased, a bundle of a plurality of PC steel materials 21 has a large diameter, which may make it difficult to carry on a truck or the like. Along with this, the capsule 4 is also large and large, and may be damaged during handling.

  On the other hand, FIG. 3B shows an embodiment according to the present invention, in which three anchor body units 2 in which a bundle of three PC steel materials 21 are inserted into the capsule 4 are bundled. The length covered with the capsule 4 is between the anchor body lengths B. In the anchor free length A, the PC steel material 21 is covered with the sheath 22.

  In the case of the multi-capsule shown in FIG. 3 (b), since the PC steel materials 21 combined into a plurality of capsules can be divided in units of 4 capsules, the anchor body unit 2 and the capsule 4 do not have a large diameter, and are transported and inserted Workability such as work is improved.

  Further, when the grout filling operation in the capsule 4 is compared, the grout 5 is filled in the capsule 4 having the anchor free length A and the anchor body length B (see FIG. 3A), so that only the capsule 4 having the anchor body length B is filled. It is clear that filling the grout 5 (see FIG. 3B) is more efficient.

  Here, Table 1 shows an example of the number of combinations of the anchor unit 2 and the capsule 4 in the conventional example and the present invention, and the allowable anchor force was calculated. The allowable anchor force shown here is calculated as Pa = min (0.7 Pu, 0.8 Py).

  The combinations shown in Table 1, a, b and c are conventional examples. A bundle of PC steel materials 21 having a diameter φ = 15.2 mm bundled with 7 pieces for a, 9 pieces for b, and 12 pieces for c are inserted into one capsule 4. The allowable anchor forces of a, b, and c in Table 1 are 1243 KN, 1598 KN, and 2131 KN.

  On the other hand, examples of the number of combinations of the tensile material 3 (PC steel material) and the capsules 4 considered in the anchor body unit 2 of the present invention are shown in d to l of Table 1. For example, taking the combination of j as an example, an anchor body unit 2 is constructed by inserting seven bundles of PC steel materials 21 having a diameter φ = 15.2 mm into the capsule 4, and the six anchor body units 2 are A large-capacity anchor 1 is bundled. The allowable anchor force in the case of j is 7459 KN.

  Comparing the conventional one capsule type shown by a to c in Table 1 and the multi-capsule type of the present invention shown by d to 1 in Table 1, it is possible to bind by bundling a plurality of anchor body units 2 each having 4 capsules. It can be seen that the anchor force is remarkably increased, making it possible to construct an anchor having a very large proof stress.

[Construction procedure]
FIG. 4 is a flowchart showing an example of the construction procedure of the large-capacity anchor 1 method according to the present invention, and FIG. 6 is a schematic explanatory diagram. FIG. 5 is an example of the insertion device 10 for the anchor body unit 2. In addition, it is not limited to the construction procedure demonstrated below.

(1) Assemble the anchor body unit 2 of 4 capsules at the factory, and transport the anchor body unit 2 around the drum-shaped exclusive winding frame 11 to the site. For example, when the anchor body unit 2 is transported by a truck or the like, the winding outer shape is about 2 m.

(2) After assembling and installing the anchor body unit 2 insertion device 10 at the site, the carried anchor body unit 2 is set in the insertion device 10 together with the dedicated winding frame 11.

(3) After the anchor body unit fixing frame 6 is suspended by the lifting device 9 provided in the insertion device 10 and set at a predetermined position, the anchor body unit 2 is pulled out from each dedicated winding frame 11, and the anchor body unit It fixes to the fixed frame 6 (refer Fig.6 (a)).

(4) The insertion device 10 is moved and installed above the hole (boring hole) 32 where the drilling has been completed (see FIG. 6B). In addition, before setting the anchor body unit 2, the insertion apparatus 10 may be installed in the upper part of the hole (boring hole) 32 by which the drilling was completed.

(5) The grout injection hose 8 is connected to the capsule 4 of each anchor body unit 2, and the cement grout 5 kneaded in the injection plant is filled in each capsule 4 (see FIG. 6B). After filling the grout 5, the inlet and the outlet are closed, and the grout injection hose 8 is removed.

(6) The large-capacity anchor 1 in which a plurality of anchor body units 2 are bundled is inserted into the boring hole 32 while slowly extending the suspension wire 7 of the lifting device 9 provided in the insertion device 10 (FIG. 6C). reference). (In the case where the insertion work is performed continuously, the grout 5 in the capsule 4 may be solidified after about one day has passed after the anchor body unit 2 is filled with the grout 5.)

(7) After inserting the large-capacity anchor 1 in which a plurality of anchor body units 2 are bundled, the anchor head 23 is fixed, and the suspension wire 7 of the lifting device 9 is removed. The replacement injection into the boring hole 32 is carried out from the bottom of the cement grout 5 kneaded in the injection plant using the grout injection hose 8 mounted before insertion, and filled to the hole opening (see FIG. 6 (d)). .

(8) After the anchor 1 is installed, the anchor head 23 is fixed and cured until the grout 5 is solidified and develops a predetermined strength.

1 ... Large capacity anchor,
2 ... Anchor body unit,
3 ... tensile material,
4 ... Capsule
5 ... grout,
6 ... Anchor unit fixing frame, 6a ... Spacer, 6b ... Fixing band,
7 ... Hanging wire,
8 ... grout injection hose,
9 ... Lifting device,
10 ... Insertion device,
11 ... Rewind frame,
21 ... PC steel (PC steel strand),
22 ... Sheath,
23 ... Anchor head,
31 ... Ground,
32 ... Boring hole,
33 ... Bedrock,
34 ... Concrete dam,
A ... Anchor free length,
B ... Anchor length,
C ... Excessive tension

Claims (3)

An anchor body portion of a tensile material is inserted into a capsule to form an anchor body unit in a capsule unit, a plurality of the capsules are bundled and fixed, and a grout is filled in each capsule, and then a boring hole provided in the ground In the large-capacity anchor method in which the boring hole is filled with grout after that, the capsule unit anchor body unit is transported to the construction site while being wound around a drum-shaped winding frame, Pull out the capsule unit anchor unit from the take-up frame to the anchor unit fixed frame supported by the insertion device installed in the section, fix it vertically, and fill the capsules with grout in that state. The large-capacity anchor construction method is characterized by being inserted into a boring hole. Mass Anchorages according to claim 1, characterized in that the capsule is fixed by bundling a plurality via a fixed frame which also serves as a positioning. The tensile member is inserted 3-20 present in one capsule, large Anchorages according to claim 1 or 2, wherein the are bundled 2-6 present the capsule.

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