KR20080025902A - Rock bolt and fixation method the rock bolt - Google Patents

Abstract

A rock bolt and a construction method of a rock bolt are provided to have early pullout strength by inserting a rock bolt coupled with a compression member and an opening member to an anchor hole of bedrock and anchoring the rock bolt mechanically, and to increase anchoring strength and to prevent corrosion permanently by injecting cement paste to an anchor hole of bedrock and anchoring a rock bolt, and then filling and hardening cement paste in a gap between an anchor hole and a rock bolt. A rock bolt includes a rock bolt main body(100) provided with a main trunk formed to a head(110) to be stepped to have a small diameter, a compression member(200) provided with plural cut-out grooves and taper compression wings on a main wall of a pipe body inserted to the main trunk of the rock bolt main body and contacted with the head, a conic opening member(300) inserted to the main trunk of the rock bolt main body and opening out the taper compression wings when pressurizing and driving the rock bolt main body and the compression member, a nut(500) fastened to a screw of the rock bolt main body, and a backing member(400) inserted to the outside of the nut and coupled with the conic opening member and supporting the conic opening member when driving the compression member. A construction method of a rock bolt comprises the steps of: injecting cement paste to many anchor holes formed on bedrock where a tunnel is excavated; inserting a rock bolt, formed by assembling a conic opening member, a compression member, a nut and a backing member to a rock bolt main body, to the anchor hole of the bedrock; opening plural taper compression wings of the compression member and compressing to the inner circumferential surface of the anchor hole of the bedrock and filling up a gap between the inside of the anchor holes of the bedrock and the rock bolt with cement paste simultaneously; and pulling the rock bolt main body until the nut contacts with the compression member and stops, and prestressing and inserting a flat plate washer to the head and fastening with a nut.

Description

Rock bolt and rock bolt construction method {ROCK BOLT AND FIXATION METHOD THE ROCK BOLT}

1 to 6 are views of the rock bolt according to the present invention,

1 is a longitudinal sectional view of a rock bolt.

2 is a partially enlarged longitudinal sectional view of the rock bolt.

3 is a plan view of the pressing member.

4 is a side view of the pressing member.

5 is an exploded perspective view of the rock bolt.

6a to 6f are longitudinal cross-sectional views showing the fixing process of the rock bolt.

<Description of the symbols for the main parts of the drawings>

1: tunnel 10: rock

20: fixing hole 100: rock bolt body

110: head portion 120: day portion

130: screw 200: pressing member

210: bottom 211: tapered crimp wing

212: notch groove 213: tapered inner diameter

300: conical expanding member 310: body

311: inclined extension surface 312: coupling portion

400: support member 410: coupling portion

500: nut 600: nut

700: flat washer 800: cement paste

The present invention relates to a rock bolt and a method for constructing the rock bolt, and in particular, the rock bolt is mechanically formed by inserting and hitting the rock bolt into the fixing hole of the rock, where the crimping member and the expansion member are coupled to the front end of the rock bolt body. It can be settled to obtain early draw strength, and cement paste is filled in the inner part of the fixing hole and the gap between the rock bolt by hardening by injecting cement paste into the inside of the rock hole and inserting and striking the rock bolt. The present invention relates to a rock bolt and a method of constructing the rock bolt, in which fixing strength is further increased, and corrosion prevention is permanently possible.

In general, after the rock is excavated at the time of tunnel construction, deformation of the rock occurs, such as cracking and jointing. Therefore, rock has a dynamic discontinuity and is connected by a kind of suture structure to stabilize the rock by inhibiting deformation early. As part of the method of maintaining the stability of the tunnel, the rock bolt is installed on the rock of the tunnel, so the early strength of the rock bolt is very important.

Conventional rock bolts are classified into wedge type, rotary expansion type, resin filling type, cement mortar filling type, etc., and the wedge type and rotation expansion type are called mechanical fixing type. There is a method of injecting cement mortar after fixing the rock bolt, but the construction process is complicated, such as mortar flows out of the hole, to avoid use.

Resin-filled type can be early quenched as a chemical product to obtain initial tensile strength, but there is a problem that durability is lowered due to chemical change over long periods of time, construction cost is high, and cement mortar-filled type obtains early drawing strength before curing There is a disadvantage that is difficult.

On the other hand, Republic of Korea Utility Model Publication No. 20-0149280 relates to a ground bolt to prevent ground collapse, which is installed to prevent the collapse of the ground inside the tunnel, in particular, it can be securely fixed rock bolts easily and easily Rock bolts for preventing ground collapse are known, which is composed of a fixed body and a moving shaft.

The fixed body has a three-part divided fixing piece having a circumferential shape connected to the hemisphere and the connecting piece, respectively, and the outer side edges of the split fixing piece are secured with outwardly engaging fastening pieces, respectively, and the locking piece and the connecting piece are divided and fixed. It is fixed with rivets in a state of being inserted into a fixing groove formed in the outer peripheral portion of the bias, and the disc and the connecting piece are also fixed by rivets.

In addition, a plurality of locking jaws are formed at the outer circumferential edge of the split fixing piece, and the inner circumferential edge is formed with a gradient surface portion, and the rear ends of each split fixing piece are elastically connected to each other by a coil spring.

Both ends of the coil spring are fixed by fixing pins in a state of being fitted into spring grooves respectively formed on both sides of the split fixing piece.

The moving shaft portion is inserted into the split fixing piece and a screw hole for fastening with the lock bolt body is formed at the center thereof, and a circular portion is formed at the front side and a tapered portion is formed at the rear side.

In addition, the attachment of the moving shaft portion is provided with a central protrusion which is inserted into and separated from the central hole of the disc.

In the conventional rock bolt, the rock bolt is inserted up to the inner end of the hole drilled in the rock, and the lock bolt body is pulled out again, unlike the rock bolt body. When the moving shaft is pulled outward in the state where the fixed body is not caught and moved in this way, the split fixing piece is moved outward by the circular part of the moving shaft part because the inner circumferential surface of the split fixing piece has a gradient surface part. It is pushed to, so that the engaging jaw formed on the outer circumferential surface of the split fixing piece is in close contact with the inner circumferential surface of the perforation is caught in a state of digging into the wall.

When the moving shaft portion is further pulled so that the split fixing piece is completely compressed to the inner circumferential surface of the drill, the moving shaft part at the front end of the lock bolt body is firmly sandwiched by the split fixing piece, and the rock bolt is firmly fixed.

This conventional rock bolt has been described as being secured primarily by the locking piece with elastic force and at the same time secured secondary locking and fixing by the split fixing piece, but according to the condition of the rock If it is made of dirt, it will be possible to settle it, but if it is rock, the plate spring member of the fixed body will not be able to dig into it. Since it is continued to slide outwards, the secondary fixing by the split fixing piece and the moving shaft part is also impossible, so that the fixing of the lock bolt is impossible.

In the rock drilling, the tip of the rock bolt body is fixed and the cement mortar is injected into the hole as before, and then the flat washer is fitted and the nut is tightened to the end of the rock bolt body to complete the fixing work. The cement mortar cannot be evenly filled in the gap between the inner shaft of the hole and the rock bolt, because the rock bolt is injected from the outside after the installation of the rock bolt. There was a problem of disappearing.

In addition, the conventional rock bolt is a structure that inserts the rock bolt main body on the inner circumferential surface of the rock and pulls it outward to fix the lock bolt body while pulling the lock bolt and tightening the lock nut, which makes the construction difficult. There was this.

Furthermore, in the conventional rock bolt, a three-part divided fixing piece having a circumferential shape is connected to a hemisphere and a connecting piece, respectively, and a locking piece that is opened in the outward direction is fixed to the side outer periphery of the divided fixing piece, and the locking piece and the connecting piece are divided. It is fixed with rivets in the state of being inserted into the fixing groove formed in the outer periphery of the fixing piece, and the disc and the connecting piece are also fixed with rivets, and the fixed body is composed. There was this.

The present invention has been made in order to solve all the problems and defects of the prior art as described above, to insert the rock bolt in the fixing hole of the rock and hit the rock bolt coupled to the front end of the rock bolt body of the compression member and expansion member By the mechanical fixation of the rock bolts, early drawing strength can be obtained.In addition, cement paste is injected into the interior of the fixing hole of the rock, and the rock bolts are inserted and blown to fix the cement. The purpose of the present invention is to provide a rock bolt and a method of constructing the rock bolt in which the fixing strength is further increased and the corrosion prevention is permanently possible by filling the gap.

In order to achieve the above object, the rock bolt according to the present invention includes a rock bolt body having a stepped portion formed stepwise so as to have a smaller diameter at one end of the head portion, and one end of the rock bolt inserted into the main portion of the rock bolt body. A crimping member formed with a plurality of cutout grooves and a tapered crimping wing, leaving a bottom at the circumferential wall of the tubular body in contact with the other end; A conical expanding member for expanding a type crimping wing, a nut fastened to the threaded portion of the lock bolt body, and a supporting member fitted to the outside of the nut to be combined with the conical expanding member and supporting the conical expanding member when the pressing member is hit. It is configured to include.

The rock bolt construction method according to the present invention includes a cement paste injection step of injecting cement paste into a plurality of fixing holes drilled in a rock to which a tunnel is excavated, and a crimping member, a conical expanding member, a nut and a supporting member to the rock bolt body. A rock bolt insertion step of assembling and inserting the assembled rock bolt into the fixing hole of the rock, and pressing the head of the rock bolt main body with an air hammer to press the advancing member against the cone-shaped expanding member to A plurality of tapered crimping wings are expanded to compress the inner circumferential surface of the fixing hole of the rock, and at the same time, the pressing member pressing and cement paste filling step of filling the cement paste into the gap between the fixing hole of the rock and the rock bolt, and the rock bolt Pull the main body and the conical extender with a tensioner until they are stopped by the base and free It is configured to include a tension tightening step of tightening the nut after inserting the plate washer in the head portion while applying stress.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail as follows.

1 to 6 are views of the rock bolt according to the present invention, Figure 1 is a longitudinal cross-sectional view of the rock bolt, Figure 2 is a partially enlarged longitudinal cross-sectional view of the rock bolt, Figure 3 is a plan view of the pressing member, Fig. 4 is a side view of the crimping member, respectively, FIG. 5 is an exploded perspective view of the rock bolt, and FIGS. 6A to 6F are longitudinal cross-sectional views showing the fixing process of the rock bolt, respectively.

As shown in the present invention, the rock bolt according to the present invention includes a rock bolt main body 100 in which the main unit 120 is stepped to have a smaller diameter at one end of the head portion 110, and

A plurality of notched grooves 212 and a tapered crimp wing part are inserted into the main part 120 of the lock bolt body 100 and leave the bottom part 210 on the main wall of the cylindrical body whose one end is in contact with the head part 110. (211) and the pressing member 200 is formed,

Conical extension member which is inserted into the other end of the main portion 120 of the rock bolt main body 100 and expands the tapered crimp wing 211 when the rock bolt main body 100 and the pressing member 200 are pressed and hit ( 300),

Nut 500 is fastened to the screw portion 130 of the lock bolt body 100,

It is configured to include a support member 400 is inserted into the outer side of the nut 500 and coupled to the conical expanding member 300 and supports the conical expanding member 300 when the pressing member 200 is hit.

For example, the rock bolt body 100 is processed into a reinforcing bar so that the main part 120 is stepped to have a smaller diameter at one end of the head part 110, and the screw part 130 is formed at the other end of the main part 120. Is formed.

The pressing member 200 has a taper in which an inner diameter gradually increases from the bottom portion 210 of the cylindrical body to which the main portion 120 of the lock bolt body 100 is fitted and one end thereof contacts the head portion 110. A mold inner diameter portion 213 is formed and a plurality of cutout grooves 212 are cut out along the longitudinal direction leaving the bottom portion 210 on the circumferential wall of the cylindrical body.

Here, the notch grooves 212 and the tapered crimping wing portions 211 of the crimping member 200 are each preferably formed at 120 degree angles, respectively, but may be added or subtracted as necessary.

The conical expanding member 300 is fitted to the other end of the main portion 120 of the lock bolt body 100 and the body 310 is inserted into the tapered crimp wing portion 211 of the pressing member 200 It is formed in a conical shape provided with an inclined expanding surface 311.

The supporting member 400 has a coupling portion 410 coupled to the coupling portion 312 of the conical expanding member 300 at the open end of the cylindrical body fitted to the outside of the nut 500.

The coupling portion 410 of the support member 400 and the coupling portion 312 of the conical expanding member 300 are coupled by screw coupling or interference fit.

In the figure, 600 shows a nut, and 700 shows a flat washer.

The rock bolt construction method according to the present invention includes a cement paste injection step of injecting cement paste 800 into a plurality of fixing holes 20 perforated in the rock 10 where the tunnel 1 is excavated and constructed;

Assembling the crimping member 200, the conical expanding member 300, the nut 500 and the supporting member 400 in the rock bolt body 100, the assembled rock bolt is fixed to the fixing hole 20 of the rock bed 10 Inserting the rock bolt into the

A plurality of tapered crimp wings of the crimping member 200 by hitting the head portion 110 of the rock bolt body 100 with an air hammer to advance the crimping member 200 against the conical expanding member 300. Compression member for expanding the 211 to the inner peripheral surface of the fixing hole 20 of the rock 10, and at the same time to fill the cement paste 800 in the gap between the fixing hole 20 and the rock bolt of the rock 10 Crimping and cement paste filling step,

The rock bolt body 100 and the conical expanding member 300 are pulled by a tensioner until the conical expanding member 300 comes into contact with the bottom 210 of the crimping member 200 and stops, and applies a prestress. After inserting the plate washer 700 in the 110 is configured to include a tension fastening step of fastening the nut 600.

Referring to the rock bolt construction work according to the present invention as described above are as follows.

In the construction of the rock bolt according to the present invention, the tunnel 1 is first excavated in the rock 10, and then drills the fixing holes 20 by the number designed in the rock 10.

Subsequently, when the rock paste is fixed to the cement paste 800 in the plurality of fixing holes 20 drilled in the rock 10, each fixing hole is set so as to be filled in the gap between the fixing hole 20 and the rock bolt. It is injected into the inner side of 20.

At this time, the cement paste 800 is adhered to the inner portion injected without flowing down the fixing hole 20 irrespective of the direction in which the fixing hole 20 is punctured, and then the fixing hole 20 when hitting the rock bolt. It is formulated to be viscous enough to spread and fill the gap between the inside and the rock bolt.

When the cement paste 800 is injected into each fixing hole 20 of the rock 10 as described above, the pressing member 200, the conical expanding member 300, the nut 500 and the supporting member to the rock bolt body 100 The lock bolt assembled with the 400 is inserted into the fixing hole 20 of the rock bed 10.

Subsequently, the head portion 110 of the rock bolt body 100 protruding out of the fixing hole 20 is hit by an air hammer.

As such, when the head portion 110 of the rock bolt body 100 is hit, the conical expanding member 300 coupled to the day portion 120 of the rock bolt body 100 is stopped by the support member 400, and thus the head portion. As the pressing member 200 pressurized by the 110 is pushed forward, each tapered pressing wing portion 211 formed in the pressing member 200 is opened by the conical expanding member 300 and the inner peripheral surface of the fixing hole 20. Squeezed on and fixed.

At the same time, the cement paste 800 injected into the inner side of the fixing hole 20 of the rock 10 spreads into the fixing hole 20 at the same time as the rock bolt is inserted, and the pressing member 200 of the rock bolt body 100 is fixed. Into the gap formed by the conical expanding member 300, the nut 500 and the supporting member 400 is filled uniformly as a whole.

At this time, the cement paste is mixed with cement and powder admixture in an appropriate amount ratio, and then, when the water mixture is mixed by mixing 20-30% of the weight of the cement, the cement paste has a viscosity that does not flow out from the vertical hole.

As described above, each tapered crimping wing portion 211 of the crimping member 200 is expanded and fixed to the fixing hole 20, and when the cement paste 800 is filled, the rock bolt body 100 and the conical expanding member 300 are provided. After pulling with a tensioner until it is stopped by the bottom 210 and inserting a flat washer 700 to the head portion 110 while applying a pre-stress to fasten the nut 600.

As described above, the rock bolt of the present invention is fixed to each tapered crimping wing portion 211 of the crimping member 200 at the moment of being installed in the fixing hole 20 of the rock 10, and mechanically firmly crimped and fixed. Thus, it can be fastened by applying prestress from the initial installation of the rock bolt, and eventually can stabilize the rock 10 at the initial stage.

When the cement paste 800 filled in the gap between the fixing hole 20 and the rock bolt of the rock 10 passes through the set time, the rock bolt is firmly fixed and fixed and the rock 10 is more firmly stabilized. .

As described above, the rock bolt according to the present invention has a very simple configuration in which a cylindrical crimping member, a conical expanding member, a nut, and a cylindrical support member are assembled in the rock bolt main body. And the cost can be reduced.

In addition, when the rock bolt is inserted into the fixing hole of the rock and the batter is pressed, the pressing member moves to the inside of the fixing hole, and the tapered crimping wing portion is enlarged by the conical expanding member to be pressed and fixed to the inner peripheral surface of the fixing hole. There is an advantage to be settled.

In addition, since the rock bolt body is to be settled and settled, it can be settled quickly as compared to being pulled out and settled firmly regardless of the condition of the rock.

In addition, after the cement paste is sufficiently filled with cement paste inside the rock, the rock bolt is inserted into the viscous cement paste, which has the advantage that the inside of the fixing hole and the space between the rock bolt are uniformly filled and cured. Therefore, there is an advantage that can increase the fixing force of the rock bolt more firmly.

Moreover, when cement mortar is injected into the fixing hole formed vertically or inclined to the rock and the rock bolt is installed, the cement mortar flows down, thereby reducing the effect of reinforcing the rock bolt fixing force, but the present invention has less fluidity than cement mortar. This cement paste is injected with high viscosity cement paste and rock bolts are installed so that the cement paste can be filled and hardened without leaking even in the fixing hole formed vertically or inclined. There is an excellent advantage, and thus can be advantageously applied to various civil works as well as much more advantageous to tunnel construction.

In particular, the present invention is to insert the rock bolt in the fixing hole of the rock and to hit the tapered crimping wing of the pressing member by the conical expansion member to fix the rock bolt mechanically firmly, so that early drawing strength can be obtained. As the bolt is mechanically fixed, it is hardened by cement paste to fix it more firmly, so that the fixing strength can be exhibited at an early stage, thereby improving rock stability and reducing construction cost in tunnel construction.

Claims (7)

Rock bolt body 100 is formed with a step portion 120 is stepped so as to have a smaller diameter than one end of the head portion 110, A plurality of notched grooves 212 and a tapered crimp wing part are inserted into the main part 120 of the lock bolt body 100 and leave the bottom part 210 on the main wall of the cylindrical body whose one end is in contact with the head part 110. (211) and the pressing member 200 is formed, Conical extension member which is inserted into the other end of the main portion 120 of the rock bolt main body 100 and expands the tapered crimp wing 211 when the rock bolt main body 100 and the pressing member 200 are pressed and hit ( 300), Nut 500 is fastened to the screw portion 130 of the lock bolt body 100, The lock is characterized in that it comprises a support member 400 is inserted into the outer side of the nut 500 and coupled to the conical expanding member 300 and supports the conical expanding member 300 when the pressing member 200 is hit. volt. According to claim 1, wherein the lock bolt body 100 is processed into a reinforcement so that the main portion 120 is stepped so as to have a smaller diameter on one end of the head portion 110 and the screw portion on the other end of the main portion 120 Rock bolt, characterized in that formed 130 is formed. The method of claim 1, wherein the pressing member 200 is other from the root portion 210 of the cylindrical body in which the main portion 120 of the lock bolt body 100 is fitted and one end thereof is in contact with the head portion 110. A tapered inner diameter portion 213 having an inner diameter gradually increasing to an end portion is formed, and a plurality of notched grooves 212 are cut out along the longitudinal direction, leaving a bottom portion 210 on the circumferential wall of the cylindrical body. . According to claim 1, wherein the conical expansion member 300 is fitted to the other end of the main portion 120 of the lock bolt body 100 to the inside of the tapered crimp wing portion 211 of the pressing member (200) Rock bolt, characterized in that formed in the conical shape is provided with an inclined expanding surface 311 is inserted into the body 310. The coupling part 410 of claim 1, wherein the support member 400 is coupled to the coupling part 312 of the conical expanding member 300 at an open end of the cylindrical body fitted to the outside of the nut 500. Rock bolt is characterized in that the formed. 4. The rock bolt according to claim 3, wherein the cutout grooves 212 and the tapered crimping wing portions 211 of the crimping member 200 are each formed at an angle of 120 degrees. Cement paste mixing injecting the cement paste 800 into the plurality of fixing holes 20 perforated in the rock 10 to which the tunnel 1 is excavated. Injection step, Assembling the crimping member 200, the conical expanding member 300, the nut 500 and the supporting member 400 in the rock bolt body 100, the assembled rock bolt is fixed to the fixing hole 20 of the rock bed 10 Inserting the rock bolt into the A plurality of tapered crimp wings of the crimping member 200 by hitting the head portion 110 of the rock bolt body 100 with an air hammer to advance the crimping member 200 against the conical expanding member 300. Compression member for expanding the (211) to compress the inner circumferential surface of the fixing hole 20 of the rock bed 10 and at the same time filling the cement paste 800 in the gap between the fixing hole 20 of the rock bed 10 and the rock bolt Crimping and cement paste filling step, The lock bolt body 100 and the conical extension member 300 are pulled with a tensioner until stopped by the bottom bottom 210, and a flat washer 700 is inserted into the head 110 while applying a prestressed nut. Rock bolt construction method characterized in that it comprises a tension fastening step of fastening (600).

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