JP2014005641A - Underground anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground anchor by which an extraction resistance force immediately after setting can be expected, and an anchor head can be engaged with an inner wall surface of an excavated hole with simple configurations.SOLUTION: An underground anchor 1 comprises: an anchor steel material 4 consisting of a fully-threaded steel bar inserted and installed in an excavated hole 3 formed in natural ground 2; a spherical convex nut 9 threadedly engaged with the tip of the anchor steel material 4; and an anchor head 5 with an extended diameter larger than that of the excavated hole 3. An elliptical plate material 10 constituting the anchor head 5 has a major axis larger than the diameter of the excavated hole 3 and a minor axis not larger than the diameter of the excavated hole 3, and is formed with an opening 11 at the center. When the elliptical plate material 10 is inserted into the excavated hole 3, the major axis section is bent to configure an insertion plate material 12 sized to allow the insertion of the elliptical plate material 10. The bent section is pushed back in the excavated hole 3 to configure the original flat elliptical plate material, and the major axis end is allowed to bite into a porous wall.

Description

  The present invention relates to an underground anchor that is inserted and fixed in a drilling hole formed in a natural ground in order to fix structures such as various mounts to the natural ground.

  Obtaining a “tension reaction force” by using steel from the natural ground The anchor ground and steel are joined mainly by the peripheral friction between the drilled hole and the grout. As a device for shortening the length, there is a method of embedding a bearing plate (disk) in a natural ground. The anchor by the bearing plate can obtain a remarkably large resistance compared with the peripheral friction, and the anchor length is short.

  Anchors that embed this bearing plate in the ground and use "passive earth pressure" as the reaction force are mainly used for embankment, and once the ground is open when the ground is soft and easy to dig by manpower at height Then, the flat iron plate is buried and returned to the original surface.

  However, if the strength of the ground is consolidated and maintained over many years, the bearing plate is fixed and reflected in the anchor strength. Therefore, it is not a good idea to loosen the ground for installing the bearing plate.

Conventionally, a technique for embedding a bearing plate in the ground without unraveling the ground has not been developed. For example, a diameter-expanding type is used in the vicinity of the tip of an anchor steel material as described in Patent Document 1 and Patent Document 2. Only underground anchors that form anchor heads have been proposed.
JP-A-6-185052 JP 2003-82662 A

  The underground anchor described in Patent Document 1 is an anchor steel material made of a tubular body, and a folded bag body is attached in the vicinity of the tip portion thereof. The hollow inside the tube was used as a vertical through-hole for injecting the grout material, and the bag body was inflated by press-fitting the grout material from a discharge port formed inside the bag body.

  That is, when the grout material filling the bag body is solidified, an anchor head having an enlarged diameter is formed. When the ground to be drilled is soft, the surrounding ground is also plastically deformed by expansion deformation of the bag body. I expected that.

  The bag body also has pores that can flow out of the grout material, and when inflated, the grout material is injected into the surrounding ground and cracks or gaps in the rock to strengthen the ground, and the circumference of the anchor head The adhesion to the surface was improved and the pulling resistance was increased.

  Moreover, the underground anchor described in Patent Document 2 has an anchor steel material in which a screw is screwed on the outer peripheral surface, and a diameter-enlarged anchor head that is attached to the tip portion thereof. This conventional anchor head has a nut screwed to an anchor steel material, a first wedge member made of a steel ball in contact with the nut, a substantially mortar-shaped movable unit disposed on the upper surface thereof, and further disposed on the upper surface thereof. It has a frustoconical second wedge member.

  The movable unit forms the lower surfaces of a plurality of movable pieces radially arranged around the anchor steel material with the same curvature as the curvature of the upper hemisphere of the first wedge member, and engages the upper surfaces with the second wedge member. It was a configuration.

  A steel pipe is loosely fitted to the anchor steel material, and the tip thereof is in contact with the rear end of the second wedge member. The back of the steel pipe is provided with an anchor plate and a nut that is screwed into the anchor steel. By tightening this nut, the anchor steel is pulled upward, and at the same time, the second wedge member is moved toward the movable unit by the steel pipe. Each of the wedge members is pressed in the direction of the movable unit, and the anchor steel material is lifted and moved by a jack so that the outer periphery of the movable piece expands in a flower shape toward the inner wall surface of the drilling hole, and the movable piece is moved to the inner wall surface. The pulling resistance was improved by locking.

  However, the conventional underground anchor that inflates the bag body cannot expect a resistance until the grout material is solidified, and the engagement between the bag body and the ground due to the expansion is not reliable. It was.

  On the other hand, the underground anchor that expands the movable unit can be expected to have a pulling resistance immediately after setting and engagement with the ground due to its mechanical structure, but the structure is complicated, and a separate movable piece is inserted into the drilling hole. Because of this, the reliability was questioned.

  The present invention has been made to solve the above-mentioned problems of conventional underground anchors, and can be expected to have a pulling-out resistance immediately after setting, and the anchor head can be securely attached to the inner wall surface of the drilling hole with a simple configuration. It aims at providing the underground anchor which can be engaged with.

  In order to solve the above-described problems, an underground anchor of the present invention includes an anchor steel material inserted and installed in a drilling hole formed in a natural ground, and an expanded-diameter anchor head formed in the vicinity of the tip of the anchor steel material. In the anchor, the anchor steel material locks a stopper in the vicinity of the tip portion, and the anchor head has a major axis larger than the drilling diameter and a minor axis smaller than the drilling diameter, and the anchor steel material is inserted in the center part. An elliptical plate material that forms an opening to be inserted, and when the elliptical plate material is inserted into the drilling hole, the long-diameter portion is bent to be an insertable plate material that can be inserted into the hole. The center tip of this insert plate is brought into contact, and the bent portion of the insert plate is pushed back between the tube disposed on the back surface to form the original flat elliptical plate, and the long-diameter end is bitten into the hole wall. Oblong It is characterized in that it is Nkaheddo.

  The anchor steel material is preferably a rod, but it may be more linear as long as the stopper is locked to the tip and can be inserted linearly into the drilling hole. In order to demonstrate the strength that the natural ground has consolidated, the diameter of the drilling hole should be the minimum hole that can be inserted into the components that will be the bearing plate. The drilled hole is closed with grout etc. to return to the same ground condition as before the drilling.

  The bearing plate component to be inserted is formed by processing an iron plate or the like with an elliptical plate material having a major axis larger than the hole diameter. An elliptical hole through which the anchor steel material is passed is opened in the center, and when inserting into the drilling hole, the upper and lower sides of the long diameter are bent to reduce it to a substantially U shape smaller than the diameter of the drilled hole and reach the bottom of the hole. Later, it is pushed at the end of the tube using a center hole jack or the like, and the bent iron plate is returned to the original long-diameter plate and pierced into the wall of the hole. At this time, the stopper receives the pushing force of the jack.

  When the hole is backfilled with grout or the like, the elliptical plate material forms a cantilever shape from the grout or the like and tries to stop on the wall of the hole. The shearing force becomes the pulling resistance of the anchor steel material.

  The insertion plate material of the underground anchor according to claim 2 is a plurality of the insertion plate materials stacked while shifting the major axis direction. Since the elliptical plate material has a structure in which only the major axis bites into the wall of the hole, it is effective to increase the rigidity to change the angle so that the major axis direction intersects at right angles or 60 degrees, etc. It would be desirable to see more and longer spreading in the shape of the petals.

  The insertion plate material of the underground anchor according to claim 3 is an insertion plate material having an abacus bead shape in which the long-diameter end portions of the bending elliptical plate material are brought into contact with each other. An elliptical plate is inserted into a plate like an abacus by bending the upper and lower sides of the major axis. You may connect the edge parts which contact | abut.

  The insert plate material for the underground anchor according to claim 4 is a plurality of sets of the abacus bead-shaped insert plate materials stacked while shifting the major axis direction. The angle is changed so that each adjacent group intersects at a right angle or 60 degrees.

  The underground anchor of the present invention uses an elliptical plate material that is bent to a size that can be inserted and then pushed back into the hole as a diameter-enlarged anchor head, so that the long-diameter end of the plate material bites into the hole wall. Even with a simple configuration, the anchor head can be reliably engaged with the inner wall surface of the drilling hole, and the pulling resistance immediately after setting can be expected, and the anchoring length of the anchor steel material is not long, and the pulling resistance Can be increased.

  The underground anchor according to claim 2 uses a plurality of insertion plate members that are stacked while shifting the major axis direction, so that it can be bitten into a wide range of hole walls and an increase in pulling resistance can be expected.

  Since the underground anchor according to claim 3 uses an insertion plate material having an abacus bead shape on the side surface, both contact portions at the time of pushing back become a central portion and the deformation is stable.

  The underground anchor according to claim 4 uses a plurality of sets of insertion plate materials in which the abacus bead-shaped insertion plate materials are stacked while shifting the major axis direction, so that the rigidity is increased and the shearing force as the pulling resistance is increased.

It is sectional drawing of the underground anchor constructed to a slope. It is the top view and front view of an elliptical board | plate material. It is the top view and front view of an insertion board | plate material. It is explanatory drawing which shows the installation process of an underground anchor. It is a front view of 2 sets of insertion board | plate materials. It is a side view of the state which pushed back two sets of insertion board materials. It is a front view which shows the example of a some insertion board | plate material.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of an underground anchor constructed on a slope. The underground anchor 1 includes an anchor steel material 4 to be inserted and installed in a drilling hole 3 formed in the natural ground 2, and an anchor head 5 in the vicinity of the tip of the anchor steel material 4. An anchor plate 6 and a nut 7 are provided on the ground surface side. Provide. After the anchor is installed, the filler 8 is pressed into the hole 3.

  The anchor steel material 4 uses a fully threaded steel rod, and a top nut 9 serving as a stopper of the anchor head 5 is screwed into the vicinity of the tip.

  The structure of the anchor head 5 will be described with reference to FIGS. 2A is a plan view of the elliptical plate material, FIG. 2B is a front view thereof, FIG. 3A is a plan view of the insertion plate material, and FIG. 3B is a front view thereof. The elliptical plate material 10 constituting the anchor head 5 has a major axis Aa larger than the diameter of the drilling hole 3 and a minor axis Ab smaller than the drilling hole diameter, and forms an opening 11 through which the anchor steel material 4 is inserted.

  When the elliptical plate member 10 is inserted into the drilling hole 3, the long-diameter portion is bent into an insertion plate member 12 having a size Ac that can be inserted. The anchor steel material 4 is inserted into the opening 11 of the insertion plate member 12 and installed in the hole.

  A procedure for inserting the insertion plate 12 into the hole 3 is shown in FIG. FIG. 4 is an explanatory view showing the installation process of the underground anchor. A drilling hole 3 is formed at a predetermined position of the ground 2 using a drilling machine (not shown). An anchor steel material 4 for screwing the top nut 9 into the hole 3 is inserted, and an insertion plate material 12 is inserted into the anchor steel material 4. The insertion plate member 12 is formed like an abacus bead by contacting the long-diameter end portions. The pipe body 13 is disposed on the back surface of the insertion plate member 12, and the anchor steel material 4 is further inserted into the center hole jack 14, and then the top nut 15 is screwed onto the outer surface (FIG. 4A).

  When the center hole jack 14 is pushed out hydraulically and the tube body 13 is pushed in, the top nut 9 serves as a pedestal to push back the bent portion of the insertion plate member 12 to obtain the original flat elliptical plate member, and the long-diameter end thereof is the hole wall. (Bit (b)).

  After pushing in, the jackwork is finished and the tube 13 is removed, and the gap between the hole and the steel is filled with sand, earth, soil cement or cement milk, and the ground force equal to or better than the ground condition before digging the hole is recovered. To do.

  Although FIG. 4 inserts one set of insertion plate members, a plurality of sets may be used. This embodiment will be described with reference to FIGS. FIG. 5 is a front view of two sets of insertion plate members, FIG. 6 is a side view of the two sets of insertion plate members pushed back, and FIG. 7 is a front view showing an example of a plurality of insertion plate members.

  An abacus bead-shaped insertion plate 16 formed by abutting the long-diameter ends of the insertion plate 12 is inserted into the stacked anchor steel 4 while shifting the long-diameter direction by 90 degrees. When pushed back, the sword is shaped like a sword as shown in FIG.

  The combination of the insertion plate materials is arbitrary, and as shown in FIG. 7A, the abacus bead-shaped insertion plate material 16 and one insertion plate material 12 may be stacked while shifting the major axis direction, or three or more sets of abacus beads FIG. 7B may be configured such that the shape insertion plate members 16 are stacked.

  The underground anchor of the present invention can obtain a predetermined tensile strength even in the case where the natural ground is not necessarily a solid natural ground or in the case of a banking slope such as a river levee, and can also be applied to such a case.

DESCRIPTION OF SYMBOLS 1 Underground anchor 2 Ground mountain 3 Drilling hole 4 Anchor steel material 5 Anchor head 9 Top nut 10 Elliptical board material 12 Insertion board material 13 Tubing body

Claims (4)

In an underground anchor having an anchor steel material to be inserted and installed in a drill hole formed in a natural ground and a diameter-enlarged anchor head formed in the vicinity of the distal end portion of the anchor steel material, the anchor steel material has a stopper in the vicinity of the distal end portion. The anchor head is an elliptical plate member having a major axis larger than a drilling hole diameter and a minor axis smaller than the drilling hole diameter, and forming an opening through which the anchor steel material is inserted at a center part. When inserting the shape plate material into the drilling hole, the long diameter portion is bent to be an insert plate material that can be inserted, and the center end of the insertion plate material is in contact with the stopper installed in the hole and disposed on the back surface. An underground anchor characterized in that it is an elliptical anchor head that pushes back the bent portion of the insertion plate material to the tube body to be an original flat elliptical plate material and bites the long-diameter end portion into the hole wall. 2. The underground anchor according to claim 1, wherein the insertion plate members are a plurality of the insertion plate members that are stacked while shifting the major axis direction. 2. The underground anchor according to claim 1, wherein the insertion plate member is an insertion plate member having a abacus bead shape in which the long-diameter end portions of the bent elliptical plate member are in contact with each other. The underground anchor according to claim 3, wherein the insertion plate material is a plurality of sets of the abacus-shaped insertion plate materials that are stacked while shifting the major axis direction.

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