JP2006257769A - Steel pipe expansion type lock bolt for connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel pipe expansion type lock bolt for connection increased in sealability and durability by reducing a difference, between portions, in an extension acting on a weld connection part between a deformed pipe end part and a sleeve when a lock bolt is expanded. <P>SOLUTION: An opening part joined to the inside of the deformed pipe formed by bending walls forming the recessed part of the end part of the deformed pipe in a zigzag shape and raising and deforming them until they touch on each other is formed at the end part of the deformed pipe to which the sleeve of the steel pipe expansion type lock bolt formed of the deformed pipe in which the recessed part for expansion is formed is fitted. The deformed pipe end part including the zigzag wall contact part of the recessed part wall is weld-connected to the inner wall of the sleeve. The plug part with screw having a through hole is joined to the sleeve having the opening part and the plug parts with screws are threaded with each other to connect the plurality of lock bolts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a steel pipe expansion type rock bolt having a high proof strength that fills a pipe body in a hole provided in a rock by pressurizing a fluid into the inside and expanding the pipe body in a radial direction by the fluid pressure. The present invention relates to a steel pipe expansion-type lock bolt for connection that can connect a lock bolt of the type.

As described in Patent Document 1, the steel tube expansion type lock bolt is a hollow deformed tube having one or more expansion recesses in the longitudinal direction. As shown in FIG. 1, a steel pipe 1 having an end sealed and a recess for expansion is inserted into a hole drilled in a rock or ground 2 (a in FIG. 2). It is expanded by using (b in FIG. 2), and the rock and the ground are consolidated with the steel pipe by bringing the hole and the steel pipe into close contact (c in FIG. 2).
In order to facilitate expansion by pressurization with a pressure fluid, the steel pipe is often provided with a concave portion in advance in the longitudinal direction (see a in FIG. 2). The distal end portion of the deformed pipe provided with the concave portion is inserted into the hole, and the rear end portion on the side into which the pressure fluid is pressed is sealed, and then the fluid inflow hole is formed. And in order to seal and make it easy to press-fit a pressure fluid, the sleeve is attached to the both ends of the deformed pipe (for example, refer patent document 2).

Usually, only one steel pipe expansion type rock bolt is inserted into the rock drilling hole and expanded. In order to make it easier to handle a rod-like body that is handled in a narrow work space such as in a tunnel, the shorter one lock bolt is, the easier it is to handle. For this reason, one lock bolt is about 2 to 6 m.
However, depending on the rock, ground, etc. of the tunnel to be excavated, or when excavating the main body after widening after advanced guidance, very long rock bolts may be required as shown in FIG. is there. In such a case, two or more lock bolts are connected and used.

In order to connect two or more lock bolts, for example, in Patent Document 3, in an inflatable pipe type lock bolt, a restraining sleeve is fitted to both ends of a pipe body, and a female thread portion is fitted to the front sleeve. Has been proposed.
In this technique, a male threaded sleeve that can be screwed to the female threaded sleeve of the first lock bolt having a female threaded portion formed on the front sleeve is fitted to the tip, and a female threaded sleeve is fitted to the rear edge. The fitted second lock bolt is screwed into the female threaded sleeve of the first lock bolt and the male threaded sleeve at the tip of the second lock bolt is coupled together. Similarly, a third lock bolt can be connected.

A placement / injection adapter is provided at the rear end of the second, third, or later lock bolt. One end of the adapter body for placing / injecting is formed with a male screw portion that is screwed into the female screw portion of the lock bolt sleeve at the back, and a receiving portion for receiving the adapter for injecting pressure fluid is formed at the other end. A hollow portion is formed inside. The hollow part is closed on the receiving part side, but the male screw side is opened, and a small hole communicating with the hollow part is formed in the receiving part. The pressure injection adapter is formed with an injection port communicating with a small hole formed in the receiving portion. When a pressure liquid injection adapter is fitted into the receiving part and pressure liquid such as pressure water is injected from the injection port, the pressure liquid passes through the small hole to the hollow part, reaches the space inside the lock bolt at the back, The diameter of the lock bolts at the intermediate part and the tip part is expanded.
Japanese Patent Publication No. 2-520 Special table 2003-501573 gazette JP 2003-148098 A

  As described above, when two or more lock bolts are to be connected, it is necessary to attach a female threaded sleeve and a male threaded sleeve to both ends of each lock bolt. In the sleeve proposed in Patent Document 3, a female threaded sleeve or a male threaded sleeve is welded to the distal end portion of the sleeve 42 that restrains the tube end of the inflatable deformed tube 41 as shown in FIG. The connecting part having the female screw part 43 or the male screw part 44 is formed in a fixed manner.

When connecting two or more lock bolts, it is necessary to secure a gap through which the pressure fluid for expanding the lock bolt is passed. When the sleeve is attached, it is necessary to completely seal the parts other than the pressurized liquid circulation space by welding.
When the sleeve is fitted to the end of the deformed pipe and then sealed by welding, the necessary welding range is widened as shown in FIG. 5A if the expansion recess remains formed. If the welding range is widened, defects such as melting of a deformed pipe portion due to welding and defective welding are likely to occur, and the time required for welding becomes longer, which is not a good solution.

For this reason, before welding a sleeve, the method of narrowing the range which shape | molds and welds a deformed pipe end part may be taken. Even when the deformed tube end portion is molded, the void portion through which the pressure fluid flows is enlarged, and the other void portion is formed to be small. As seen in FIG. The cross section is asymmetric.
However, when a lock bolt manufactured by welding and sealing a sleeve to a deformed pipe having a cross-sectional shape is expanded with a pressurized fluid, cracks occur in the welded part and the heat-affected part due to the tensile force in the longitudinal direction generated during expansion. It becomes easy. Further, since the tensile force remains as residual stress even if no crack is generated, there is a risk of causing stress corrosion cracking or the like.

  The present invention has been devised to solve such a problem, and in a connecting steel pipe expansion type lock bolt in which sleeves attached to the end parts of a deformed pipe are joined together, It is an object of the present invention to provide a connecting steel pipe expansion type lock bolt with improved sealing performance and durability by reducing the tensile force acting on the welded joint between the sleeve and the sleeve.

  In order to achieve the object, the connecting steel pipe expansion type lock bolt of the present invention comprises a deformed pipe formed with a concave part for expansion, and has a closed end and the other end to which the sleeve is attached, An opening connected to the inside of the deformed pipe formed by bending up and deforming the wall forming the concave portion of the end portion into a zigzag shape and abutting each other is provided. The end portion of the deformed pipe including the portion is welded to the inner wall of the sleeve.

  The connecting steel pipe expansion type lock bolt of the present invention is also formed of a deformed pipe formed with a concave part for expansion, and the walls forming the concave part of the end part are bent in a zigzag manner at both ends where the sleeve is attached. An opening connected to the inside of the deformed pipe formed by being lifted and deformed until it abuts each other is provided, and the end of the deformed pipe including the serpentine wall abutting portion of the concave wall is welded to the inner wall of the sleeve. It is characterized by.

  The connecting steel pipe expansion type lock bolt of the present invention further comprises a deformed pipe formed with a concave part for expansion, and a wall forming the concave part of the end part is bent into a zigzag shape at one end where the sleeve is attached. An opening connected to the inside of the deformed pipe formed by being lifted and deformed until it abuts each other is provided, and the end of the deformed pipe including the serpentine wall abutting portion of the concave wall is welded to the inner wall of the sleeve. And a pressurizing sleeve connected to a pressurized fluid supply source is attached to the other end.

  According to the present invention, the deformed tube formed by deforming the end of the deformed tube to which the sleeve is attached to the deformed tube by bending the walls forming the concave portion of the end into a zigzag shape and coming into contact with each other. An opening connected to the inside of the tube is provided, and the end portion of the deformed pipe including the serpentine wall contact portion of the concave wall is welded to the inner wall of the sleeve. For this reason, the range to weld can be made small and the lock bolt excellent in airtightness can be provided.

  Moreover, since the lower side wall of the pipe end recess is lifted upward and welded to the inner wall of the sleeve, the amount of expansion between the upper part and the lower part of the concave part of the deformed pipe generated when the lock bolt is pressurized and expanded. The difference can be reduced, and the tensile stress generated above the concave part of the deformed pipe can be reduced to suppress the occurrence of cracks and stress corrosion cracks in the welded part and weld heat affected zone. A steel pipe expansion type lock bolt can be provided.

  As shown in FIG. 4, the conventional expansion lock bolt for connection made of a deformed pipe has a female screw part 43 or a male screw part 44 separately from the sleeve 42 main body for restraining the pipe end of the deformed pipe 41. The parts are fixed to the sleeve by welding. The deformed pipe and the sleeve are also welded to each other at the end of the deformed pipe.

  At this time, since the sleeve is welded and joined to the sleeve in the shape of the irregular tube end as shown in FIG. 5 (a) or (b), when the lock bolt is pressurized and expanded, The expansion length is different. This difference in expansion length increases the difference in tensile stress generated in the longitudinal direction, causing cracks in the welded part or welded heat-affected zone, and stress corrosion cracking even before cracks occur, resulting in durability It was speculated that it was a cause of lowering.

Therefore, the present inventors have studied various means for reducing the difference in residual stress between the upper side and the lower side of the concave portion with fewer welding required portions.
As a result, it has been found that the end recessed portion shape of the deformed tube can be achieved by changing the shape as shown in FIG.
By setting it as such a shape, a welding required location reduces compared with Fig.5 (a).

Further, when the expansion amount when the lock bolt is pressurized and expanded after welding the sleeve is welded, in the conventional example (FIG. 7A), there is a difference in expansion amount between the upper side and the lower side of the concave portion of the deformed pipe. On the other hand, the difference is smaller in the lock bolt according to the present invention (FIG. 7B).
For this reason, in the lock bolt according to the present invention, there is a small difference due to the site of the tensile stress generated at the time of pressurization and expansion, and there is a possibility that a crack may occur in the welded part or the weld heat-affected zone or a stress corrosion crack may occur after that. Less.

Next, a method for forming an opening of a predetermined shape at the end of the deformed pipe in which the expansion recess is formed will be described.
The steel pipe expansion type lock bolt is made of an electric-welded steel pipe and made of a hollow deformed pipe having an expansion recess extending in the longitudinal direction by a multi-stage roll forming method or the like.
The cross-sectional shape of the hollow deformed tube having the expansion recess extending in the longitudinal direction is usually as shown in FIG. Therefore, a concave portion is formed by pushing a die 10 in which a conical portion having an elliptical cross section and a cylindrical portion having an elliptical cross section as shown in FIG. The walls are bent in a zigzag shape and are lifted and deformed until they come into contact with each other to form an opening (see FIGS. 6 and 7B).

FIG. 6 does not show the sleeve attached to the tube end, but after forming the opening in the above-described manner, the deformed tube end and the sleeve inner wall including the serpentine wall abutting portion of the recess wall are formed. And welded together.
After inserting the lock bolt provided with the pipe end opening formed in the above-described manner into the hole provided in the rock, after connecting the sleeves of the lock bolt having the opening, the pressure bolt is expanded. Next, a connection mode between the sleeves of the lock bolt will be described.

If rock bolt sleeves can be welded together when placing rock bolts on the rock, they are connected by a welding method. In other cases, it is preferable to attach a connecting part to the end of the lock bolt in advance.
It is preferable to use a threaded plug as the connecting part and to weld the plug in advance to the sleeve.

Examples of the joining form of the threaded plug include, but are not limited to, embodiments as shown in FIGS. The sleeve and the connecting plug may be integrated. In FIG. 10, a threaded plug 12 is fitted and fixed to a sleeve 11 attached to the tube end of the atypical tube. One end of a plug portion with a male screw having a through hole in the opening of the sleeve and having a male screw formed on the outer peripheral surface may be press-fitted and fitted, and the fitting portion may be welded. In this case, the threaded plug may be a female threaded plug in which a female thread is formed on the inner peripheral surface.
In FIG. 11, a threaded plug 13 is welded and fixed to the end surface of the sleeve 11. The screw structure of the plug and the point having the through hole are the same as described above.

Next, the end structure of the connecting lock bolt to which the threaded plug is attached in the mode shown in FIG. 10 and the connecting mode will be described.
The lock bolt initially inserted into the hole provided in the rock is closed at the tip and has a male threaded plug at the rear end. In addition, a threaded plug portion is fixed to both ends of the intermediate lock bolt. Further, a threaded plug portion is fixed to the front end of the lock bolt for subsequent use, and a pressurizing sleeve connected to a pressurized fluid supply source is attached to the rear end.

  First, insert the head lock bolt into the hole excavated in the rock. Subsequently, the intermediate lock bolt is connected to the rear end of the front end lock bolt by screwing the plug portion provided at the front end of the lock bolt into the plug portion at the rear end of the front lock bolt, Push the lock bolt further into the hole. At this time, as shown in FIG. 12, when the screw part attached to the plug 12 cannot be screwed in the same type, it can be easily connected by using the connection auxiliary component 14.

If necessary, an intermediate lock bolt is further connected, and finally a subsequent lock bolt is connected. The connection mode is the same as described above.
Since the threaded plug portion has a through hole, the internal space of the tip lock bolt communicates with the internal space of the intermediate lock bolt and the internal space of the subsequent lock bolt. Therefore, when the lock bolt inflating fluid is press-fitted from the pressurizing sleeve attached to the rear end of the subsequent lock bolt, all the lock bolts are simultaneously expanded.

Three kinds of lock bolts were produced on the assumption that three lock bolts were connected.
Using a deformed tube with a plate thickness of 2.0 mm, an outer diameter of 36 mm, and a length of 2 m, and a concave section, a sleeve having an inner diameter of 36 mm, an outer diameter of 38.1 mm, and a length of 70 mm is attached and welded to form a sealed end. did.
After the same shaped sleeve was attached to the other end, a mold was pushed into the tube end to form an opening. As the mold, as shown in FIG. 9, a conical portion having an elliptical cross section having a longitudinal direction of 25 mm and a width direction of 19 mm, and a cylindrical portion having an elliptical cross section having a longitudinal direction of 25 mm and a width direction of 19 mm and a height of 5 mm. A mold consisting of was used. A plug portion provided with a male screw portion having an outer diameter of 36 mm, a length of 40 mm, and a length of 30 mm was press-fitted into the opening of the sleeve attached to the tube end where the opening was formed, and the press-fit portion was welded. Note that a through hole having a diameter of 5 mm is formed in the plug portion in advance.

  The same type of deformed tube was used as the second type of lock bolt, and the same shape sleeve was attached to both ends, and then the same shape mold was pushed into both tube ends to form openings. A plug portion provided with a male screw portion having an outer diameter of 36 mm, a length of 40 mm, and a length of 30 mm was press-fitted into the openings of both sleeves attached to the pipe ends where the openings were formed, and both the press-fit portions were welded and joined. .

The same type of deformed pipe was used as the third type of lock bolt, and the same shape sleeve was attached to the tip, and then the same shape mold was pushed into the end of the pipe to form an opening. A plug portion provided with a male screw portion having an outer diameter of 36 mm, a length of 40 mm, and a length of 30 mm was press-fitted into the opening of the sleeve attached to the tube end where the opening was formed, and both the press-fit portions were welded. After the same sleeve was attached and welded to the side where the opening was not formed, a water injection hole was drilled to form a pressurized fluid supply end similar to the conventional one.
As shown in FIG. 12, the three lock bolts thus manufactured are connected using a connection auxiliary part having an internal thread formed on the inner peripheral surface, and water is pumped from the water injection sleeve of the rear end lock bolt. When the lock bolts were expanded, the three lock bolts were uniformly expanded without deforming the periphery of the connecting portion.

The figure explaining the aspect which expands a steel pipe lock bolt and reinforces the ground Diagram explaining how to apply pressure before and after pipe expansion The figure explaining the aspect which connects and uses a lock bolt The figure explaining the conventional lock bolt connection mode The figure explaining the welding required part at the time of welding sealing the pipe end of a deformed pipe The figure explaining the shape of a pipe end opening part formed by this invention, and a welding required location The figure explaining the difference in the tensile stress at the time of lock bolt pressurization expansion in the conventional example and the present invention example The figure explaining the cross-sectional shape and opening formation position of a deformed pipe The figure explaining the mold shape for opening part formation The figure explaining the end part structure of the lock bolt which inserted the plug part with the screw in the sleeve The figure explaining the end part structure of the lock bolt which welded and connected the plug part with the screw to the sleeve end part The figure explaining the connection mode using the steel pipe expansion type lock bolt of the present invention

Claims (3)

  It consists of a deformed tube with an inflating recess, the tip is closed, and the wall that forms the recess at the end is folded into a zigzag shape at the other end where the sleeve is attached, until they come into contact with each other An opening connected to the inside of the deformed pipe formed by being lifted and deformed is provided, and the end of the deformed pipe including the serpentine wall abutting portion of the concave wall is welded to the inner wall of the sleeve. Steel pipe expansion lock bolt for connecting.   It consists of a deformed tube with an indentation recess, and the walls that form the recess at the end are folded into a zigzag shape at both ends where the sleeve is attached and lifted and deformed until they come into contact with each other. A steel pipe expansion lock bolt for connection comprising an opening portion connected to the inside of the deformed tube, and an end portion of the deformed tube including a serpentine wall contact portion of the recessed wall welded to the inner wall of the sleeve .   It consists of a deformed tube formed with a recess for expansion, and is shaped by being lifted and deformed at one end where the sleeve is attached until the wall forming the recess at the end is bent into a zigzag shape and abutted against each other An opening connected to the inside of the deformed tube is provided, and the end of the deformed tube including the serpentine wall contact portion of the concave wall is welded to the inner wall of the sleeve and connected to the pressurized fluid supply source at the other end A connecting steel pipe expansion type lock bolt, wherein a pressurizing sleeve is attached.

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