KR20050031042A - Ground anchor and fixing head thereof - Google Patents

Abstract

A ground anchor and an anchorage head of the ground anchor are provided to place and insert the ground anchor to a bore easily, and to minimize decrease of fixing force by placing a grout injection tube in the ground anchor. A ground anchor is composed of a tendon, a tubular tendon protection member formed in a free part to insert the tendon, a tubular anchorage member(310) formed in a lower part of the tendon protection member and composed of a hollow for inserting the tendon and an uneven part formed in an outer periphery, an anchorage head(320) arranged in a lower part of the anchorage member to fix the tendon, and a protection cap(370) formed in a lower part of the anchorage head to protect the tendon protruded in the lower part of the anchorage head. The anchorage head comprises a grout inlet(322) formed in an upper part, a grout outlet formed in an outer periphery, a guide pipe connecting the grout inlet to the grout outlet, and a grout injection tube connected to the grout inlet of the anchorage head and inserted to the tendon protection member and the anchorage member with the tendon.

Description

Ground anchor and ground anchor head {GROUND ANCHOR AND FIXING HEAD THEREOF}

The present invention relates to a ground anchor using a high-strength tension member to stabilize the structure or excavating wall by fixing in the ground and applying a high load to the tension member, and a fixing head of the ground anchor used therein.

There are two ground anchors: temporary anchors and permanent anchors.

Hypothetical anchor refers to a period of about 12 to 24 months of use after being buried in the ground, and permanent anchor refers to an anchor that is buried in the ground for more than 24 months or permanently. Permanent anchors must be permanently settled after being buried in the ground, so thorough preparation must be followed for treatment methods and load transfer methods.

The ground anchor is divided into a fixing part, a free part and an anchor head. The fixing unit transmits the necessary load to the ground, the free unit transmits the given load to the fixing unit, and the anchor head fixes the given load to maintain the load on the free unit and the fixing unit.

The tension member used for the free part and the anchor part of the ground anchor usually uses a PC strand or a steel bar.

The structure for fixing the tension member uses a wedge method mainly using wedge cone in the case of a stranded wire, and a nut method mainly in the case of a steel bar.

In the construction of the ground anchors, the ground is drilled to a predetermined depth and diameter, the fixing part is inserted into the perforations, and the grout (cement paste) is filled. When a predetermined seal for hardening of the grout has elapsed, the tension member is tensioned with a predetermined load to stabilize the anchor head to stabilize it.

At this time, the injection of grout is provided with a tab on the outer periphery of the fixing unit to mount the grout injection tube on the tab, insert the grout injection tube with the fixing unit, and then grout is injected through the grout injection tube.

According to the conventional technology, construction and structural problems occur.

First, it is difficult to insert the ground anchor into the perforation due to the grout injection tube provided at the outer periphery of the fixing unit.

In addition, although the fixing unit should be inserted and fixed along the center of the drilling unit, it is difficult to locate the fixing unit in the center of the drilling unit due to the grout injection tube provided in the outer peripheral portion of the fixing unit.

In addition, the grout injection tube reduces the amount of grout injected into the perforation portion, and also provides a separate tab for mounting the grout injection tube on the outer periphery of the fixing unit, thereby reducing the fixing force of the fixing unit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to eliminate the above problems by placing the grout injection tube inside the ground anchor.

The present invention, in order to solve the above problems; Tension member protection means provided in a free portion in the form of a tube into which the tension member is inserted; A tubular fixing member provided below the tension member protecting means and having a hollow formed therein to insert the tension member, and having irregularities formed on an outer circumferential surface thereof; A fixing head provided below the fixing body to fix the tension member; A protective cap provided below the fixing head to protect the tension member protruding to the lower portion of the fixing head; A ground anchor comprising: the fixing head has a grout inlet formed on an upper surface thereof, a grout inlet formed on an outer circumferential surface thereof, and an induction pipe connecting the grout inlet and the grout outlet formed therein; A grout injection tube having one end connected to the grout inlet of the fixing head and inserted into the tension protecting means and the fixing body together with the tension material; Characterized in that comprises a.

In the above, it is preferable that a plurality of grout outlets are formed along the outer circumferential surface of the fixing head, and more preferably, the outer circumferential surface of the fixing head is equally divided and arranged at equal intervals. According to this structure, the grout flowing out of the fixing head radially flows out at equal intervals, so that the fixing head is naturally located at the center of the perforation due to the pressure of the grout.

According to another aspect of the present invention, in the anchoring head of the ground anchor provided in the anchoring portion of the ground anchor is fixed to the tension member, the fixing head has a grout inlet is formed on the upper surface, the grout outlet is formed on the outer peripheral surface, the inside The grout inlet and the grout outlet is characterized in that the induction pipe is formed.

Hereinafter will be described in detail the configuration and operation of the present invention by one embodiment of the present invention.

1 is a schematic longitudinal cross-sectional view showing a partial incision before mortar injection according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along line AA of Figure 1, Figure 3 is an enlarged bottom view of Figure 1, Figure 4 is a BB line of FIG. It is sectional drawing, FIG. 5 is sectional drawing of the CC line of FIG. 3, FIG. 6 is sectional drawing of the DD line of FIG. 3, and FIG.

In the present embodiment, the tension member 110 uses an unbonded PC strand, and in this embodiment, four tension members 100 are provided.

Each tension member 110 is composed of seven twisted strands consisting of a central strand 111 of one strand located in the center and the outer address line 112 of six strands twisted along the central strand, the seven strands of twisted strand The outer circumference is protected by a coating material, and the inside of the coating material is filled with grease. In addition, each tension member is in a state where the coating material at both ends is peeled off to be fixed to the fixing unit and the anchor head.

As shown in FIG. 2, the grout injection tube 120 is positioned between the four tension members 110.

The tension members 110 and the grout injection tube 120 are inserted in the tubular tension member protection means 210 provided in the free portion of the ground anchor. Although the PE pipe is illustrated as the tension member protecting means 210 of the present embodiment, a corrugated pipe may be used in some cases.

A fixing body 310 is provided below the tension member protecting means 210.

Fixture 310 is formed in a tubular shape, the hollow is formed therein, the tension members 110 and grout injection tube 120 extending from the free portion is inserted together, the outer peripheral surface is formed with irregularities in order to be fixed with the grout It is.

On the other hand, the first coupler 311 is screwed to the upper inner circumferential surface of the fixture 310, the tensile material protection means on the inner circumferential surface of the first coupler 311 to connect the fixing unit 310 and the tensile material protection means 210 210 is screwed in.

A fixing head 320 is provided below the fixing body 310.

The tension member 110 is fixed by the fixing head 320 at the bottom of the ground anchor.

The fixing head 320 and the fixing body 310 are screwed together. The fixing head 320 and the fixing body 310 may be integrally formed, but for the convenience of manufacturing, the fixing head 320 and the fixing body 310 are separated and manufactured, and then screwed together.

Four lower wedge cone fastening portions 321 to which four lower wedge cones 330 are coupled are formed in the fixing head 320.

Four tension members 110 are fixed by four lower wedge cones 330 while penetrating the four lower wedge cone fastening portions 321 of the fixing head 320. As such, the fixing structure of the stranded wire using the wedge cone is widely used in the related art, and various methods are widely known.

Meanwhile, a grout inlet 322 is formed at the center of the upper surface of the fixing head 320, and four grout outlets 323 are formed at an outer circumferential surface of the fixing head 320 along the outer circumferential surface of the fixing head 320 at 90 ° intervals. It is.

An induction pipe 324 is formed in the fixing head 320 to connect the grout inlet 322 and the grout outlet 323, and when the grout is injected into the grout inlet tube 120, the grout inlet 322 is formed. The grout is injected into the perforation via the grout outlet 323 via the induction pipe 324.

The grout inlet 322 of the fixing head 320 is connected to one end of the grout injection tube 120, the second coupler 121 is provided at one end of the grout injection tube for the connection, the second coupler 121 is fixed The inner peripheral surface of the grout inlet 322 of the head 320 is screwed.

 Therefore, the grout flowing out of the fixing head 320 radially flows out at the same interval, so that when the grout is injected, the fixing head 320 is naturally located at the center of the perforation due to the same pressures of the grout radially occurring.

The grout outlet 322 is formed on the outer circumferential surface of the fixing head 320 in consideration of the fact that the outer circumferential surface of the fixing head 320 does not increase the fixing force, unlike the outer circumferential surface of the fixing body 310. will be.

A protective cap 370 is provided below the fixing head 320 to protect the tension member 110 therein.

In addition, in order to connect the protective cap 370 and the fixing head 320, the connection fixing body 360 is inserted between the two ends are formed therebetween, and the outer peripheral surface of the connecting fixing body 360 is formed with irregularities to grout Increase friction with.

Connection fixing body 360 basically has a function of the protective cap 370, more than one connection of the fixing fixture 360 and the protective cap 370 is manufactured separately, so the anti-loosening disk 380 to be described later connected It may be provided inside the fixing member 700.

Four tension members 110 protruding to the bottom of the fixing head 320 is integrated while twisting each other at the inlet portion of the protective cap 370.

In addition, the four tension members 110 are gathered to the center while passing through the connection fixing body 360 to be integral with each other at the inlet portion of the protective cap 370.

As a method of twisting four tension members 110 integrally, a method of twisting four strands by treating each strand as one strand may be considered. However, in the present embodiment, six outer address lines 112 of each strand may be considered. After unpacking each of the two, four center wires (111) and 20 outside address lines (112) were gathered in the center side by side, and the remaining eight outer address lines (112a) were combined with four center wires (111). Twist around the 20 outer address lines (112) to form a single stranded structure. According to the experiment, in the case of most of the stranded wire, the center wire 111 was found to be very difficult to twist compared to the outer address line 112, and thus the twisting work was performed using some strands of the outer address line 112.

An anti-loosening disk 380 is provided inside the protective cap 370.

The anti-loosening disk 380 has a central through hole 381 formed at the center thereof.

The tension member 110 formed of one stranded wire structure is inserted into the central through hole 381.

Therefore, when the plurality of tension members 110 are integrally unwound, the outer diameter formed by the eight outer address lines 112a is expanded and tightened by the central through hole 381, resulting in the central through hole 381. It is prevented that the outer address line 112a of the plurality of tension members 110 which are integrally formed by loosening.

Meanwhile, the pressing plate 340 and the support member 350 are inserted between the lower surface of the fixing head 320 and the confluence point 110a at which the plurality of tension members 110 are integrally formed.

The lower portion of the support member 350 is formed with four support jaws 351 which protrude radially between four tension members 110 branched from the confluence point 110a, and the support jaws 351 extend upwards. The cross section of the support member 350 is made of "+" shape. In the present embodiment, since four tension members are used, four support jaws 351 may be formed. If six or eight tension members are used, six or eight support jaws may be formed.

The pressing plate 340 is inserted between the upper surface of the support member 350 and the lower surface of the fixing head 320, more specifically, the lower surface of the lower wedge cone 330.

The pressing plate 340 has a disc shape, and four tension member through-holes are formed to penetrate the four tension members. Thus, the pressing plate 340 can move freely along the tension member 110 in the longitudinal direction.

In the present embodiment, the pressing plate 340 and the support member 350 are separately manufactured for ease of manufacture, but the case in which the speech is formed is not excluded.

According to the structure as described above, if any one of the tension member 110 is pulled to the ground in order to dissipate the tension due to breakage of any one of the lower wedge cone 330 to the twist structure of the tension member integrated from the joining point (110a). Thereby preventing any one of the tension members 300 from being pulled to the ground.

In addition, since the outer diameter of the twisted structure of the tension member 110 integrated is limited by the central through hole 381 of the anti-loosening disk 380, as a result, the twisting is prevented.

In addition, even when all four lower wedge cones 330 are damaged, the twisted structure of the integrated tension member is moved to the upper part as a whole. The supporting member 350 is to squeeze the pressing plate 340, the squeezing plate 340 squeezed by the supporting member 350 is to squeeze the lower surface of the lower wedge cone 330, the lower wedge cone 340 is firmly coupled to the lower wedge cone fastening portion 321 of the fixing head 320, as a result is to prevent the tension of the tension member 110 is reduced or eliminated.

Figure 8 is a schematic longitudinal cross-sectional view of a partially cut after construction of the embodiment according to Figure 1, the anchor head is fixed after the grout is injected.

Since the lower part of the ground anchor is the same as that of FIG.

A pressure plate 450 having a through hole formed in the ground is provided, and the pressure plate 450 receives a load by the tension of the tension member 110 from the re-tension type anchorage 410 and distributes it to the ground.

The re-tensioning anchorage 410 is provided on the top of the pressure plate 450, the connecting plate 440 is inserted between the re-tensioning anchorage 410 and the pressure plate 450.

The retractable anchorage 410 is formed with an upper wedgecon fastening portion for accommodating the upper wedge cone 420, and a tension member 110 penetrates the upper wedge cone fastening portion, and the tension member 110 is an upper wedge cone 420. It is fixed to the re-tension anchorage 410 by. Thus, the fixing of the tension member by the wedge cone is a well-known technique known in the art.

On the other hand, on the upper outer peripheral surface of the re-tensioning anchorage 410, a thread for re-tension 411 is formed, so that the re-tensioning device can be coupled when re-tension of the tension material described later.

In addition, the lower outer periphery of the re-tensioning anchorage 410 is tapered to correspond to the tapered surface of the bearing plate 470 when the tension member is re-tensioned.

A threaded through hole is formed in the center of the connecting plate 440, and a connecting pipe 460 which is extended downward to surround the tension protecting member 210 is screwed to the threaded through hole of the connecting plate 440, thereby extending the tension protecting member 210. The upper part of is cut off from the outside.

The upper protective cap 430 is mounted on the upper surface of the connecting plate 440.

In addition, one side of the upper surface of the upper protective cap 430 is provided with a grease injection nozzle for injecting grease.

The grout injection tube 120 is left with its top cut after grout injection and prior to mounting of the anchor head.

FIG. 9 is a schematic longitudinal cross-sectional view of a partial cutaway of the anchor head after retension of FIG. 8, and FIG. 10 is a perspective view of the bearing plate.

Since the tensile load of the tension member decreases with time after a certain period of time after the construction of the ground anchors, it is necessary to retension the tension member in some cases.

9 is a schematic longitudinal cross-sectional view of a partially cut away after the tension member is retensioned.

When the tension member is re-tensioned, the upper protective cap 430 is first removed, and then the re-tension device (not shown) is coupled to the re-tightening thread 411 of the re-tensioning anchorage 410 to re-tension the tension member 110. . Therefore, the re-tensioning anchorage 410 moves upward depending on the amount of tension member 110 is re-tensioned.

The bearing plate 470 is inserted between the re-tensioning anchorage 410 and the connecting plate 440 to maintain the state of the re-tensioning anchorage 410 moved upward.

Bearing plate 470 can be made in the form of a disk formed in the hollow is divided into two, such as domestic Patent Publication No. 2000-0054007 "Head and re-tensioning device of civil engineering, re-tensioning anchor for construction" This method has a disadvantage in that bearing plates of different thicknesses must be provided according to the height change of the re-tensioning anchorage 410.

Therefore, in the present embodiment, the tapered surface is formed on the upper inner circumference of the bearing plate 470, and correspondingly, the tapered process is performed on the lower outer circumference of the restrainable anchorage 410, thereby re-straining the bearing plate 470. To be inserted into the bottom of the fixing unit 410.

Therefore, the degree of insertion of the bearing plate 470 is adjusted according to the height change of the re-tensioning anchorage 410 by the corresponding tapered surface, so that only one bearing plate 470 of the various re-tensioning anchorage 410 is used. Can cope with height change.

FIG. 10 is a perspective view of the bearing plate 410 of FIG. 9, where the embodiment of FIG. 9 requires a pair of bearing plates of FIG. 10. In the present embodiment, the bearing plate is divided into two parts, and in some embodiments, the bearing plate is divided into three or four parts.

After performing the retensioning operation as described above and mounting the upper protective cap 430, the grease is injected through the grease injection nozzle to complete the retensioning operation.

The above embodiment is only a preferred embodiment of the present invention, the technical spirit of the present invention can be variously modified or adjusted by those skilled in the art, and if such modifications or adjustments use the technical spirit of the present invention, it is within the scope of the present invention. will be.

The present invention places the grout injection tube inside the ground anchor so that the grout flows out of the ground anchor, thereby facilitating the operation of inserting the ground anchor into the perforation, and positioning the ground anchor in the center of the perforation. It is easy to work with and can solve the reduction of fixation force due to grout injection tube.

1 is a schematic longitudinal cross-sectional view showing a partial incision before mortar injection of an embodiment according to the present invention,

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

3 is an enlarged bottom view of FIG. 1;

4 is a cross-sectional view taken along the line B-B of FIG.

5 is a cross-sectional view taken along the line C-C of FIG.

6 is a cross-sectional view taken along the line D-D of FIG. 3;

7 is a cross-sectional view taken along the line E-E of FIG.

8 is a schematic longitudinal cross-sectional view of a partially cut after the construction of one embodiment according to FIG.

9 is a schematic longitudinal cross-sectional view of a partial cutaway of the anchor head after retension of FIG. 8;

10 is a perspective view of the bearing plate of FIG.

<Description of Symbols for Main Parts of Drawings>

110: tension member 120: grout injection tube

210: tensile material protection means 310: fixture

320: fixing head 322: grout inlet

323 grout outlet 324 guide tube

370: protective cap

Claims (8)

Tension member; Tension member protection means provided in a free portion in the form of a tube into which the tension member is inserted; A tubular fixing member provided below the tension member protecting means and having a hollow formed therein to insert the tension member, and having irregularities formed on an outer circumferential surface thereof; A fixing head provided below the fixing body to fix the tension member; A protective cap provided below the fixing head to protect the tension member protruding to the lower portion of the fixing head; In ground anchors comprising: The fixing head has a grout inlet formed on an upper surface thereof, a grout outlet formed on an outer circumferential surface thereof, and an induction pipe connecting the grout inlet and the grout outlet formed therein; A grout injection tube having one end connected to the grout inlet of the fixing head and inserted into the tension protecting means and the fixing body together with the tension material; Ground anchors comprising a. The ground anchor according to claim 1, wherein the grout outlet is formed in plural along the outer circumferential surface of the fixing head. 3. The ground anchor as claimed in claim 2, wherein the grout outlets are equally divided by the outer circumferential surface of the fixing head. The ground anchor of claim 1, wherein the tension member is provided in plural, the grout injection tube is positioned between the tension members, and the grout inlet of the fixing head is formed at the center of the upper surface of the fixing head. . The ground anchor according to claim 4, wherein the tension member is made of an unbonded strand. In the anchoring head of the ground anchor provided in the anchoring portion of the ground anchor is fixed to the tension member, the fixing head has a grout inlet is formed on the upper surface, a grout outlet is formed on the outer peripheral surface, the grout inlet and the grout therein The anchoring head of the ground anchor, characterized in that the guide pipe connecting the outlet is formed. The fixing head of the ground anchor according to claim 6, wherein the grout outlet is formed in plural along the outer circumferential surface of the fixing head. 8. The anchoring head of the ground anchor according to claim 7, wherein the grout outlet is equally divided by the outer circumferential surface of the fixing head.