Mounting and anchoring method for self-expanding type expanded-head anchor rod for supporting broken surrounding rock roadway

Abstract

The invention discloses a mounting and anchoring method for a self-expanding expanded-head anchor rod for supporting a broken surrounding rock roadway. The mounting and anchoring method comprises the following steps: S1, drilling an anchoring hole; s2, reaming operation is conducted on the hole bottom of the anchoring hole; s3, filling the self-expanding expanded-head anchor rod into the expanded anchoring hole; s4, grouting and hole sealing operation is conducted on the hole opening of the anchoring hole; and S5, grouting, filling and anchoring are conducted in the anchoring holes. The requirement for the diameter of the anchoring hole is not high, the size of the expansion piece can be designed fully according to the reaming size of the expanded-base filling bottom, the effect of expanded-base filling reaming anchoring is fully exerted, the rated anchoring force of an anchoring system is improved, the stability of the anchoring system is enhanced, and the method has important significance on safe and efficient mining and supporting of a mine.

Description

Technical Field

[0001] The invention belongs to the technical field of mine tunnel support, and in particular relates to an installation and anchoring method of a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel. Background Art

[0002] At present, bolt support has become one of the most commonly used support methods for coal mine tunnels due to its advantages of low cost, high efficiency, and low labor intensity. Especially in tunnels with difficult maintenance such as coal tunnels and soft rock tunnels, resin anchoring is usually used to control the stability of the tunnel surrounding rock. However, since ordinary anchor holes in coal tunnels and soft rock tunnels are prone to slip failure, multiple support and renovation of such tunnels consumes a lot of manpower, material and financial resources, resulting in a significant increase in the construction time of resin anchor hole drilling, reducing the efficiency of bolt support and affecting the mining speed of coal mines. Bottom expansion and backfill anchoring is an effective support method to solve the problem of bolt slip failure. However, the diameter of the enlarged head of the ordinary enlarged head anchor in the bottom expansion and backfill anchoring support is greatly affected by the diameter of the anchor hole, making it difficult to play the role of the enlarged head anchor and the strengthening support effect of the bottom expansion and backfill anchoring.

[0003] Therefore, in view of the above-mentioned deficiencies in the anchoring performance of the current resin anchor rods, there is an urgent need for a self-expanding enlarged head anchor rod for use in cracked surrounding rock tunnel support for bottom expansion and backfill anchoring. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel, which is easy to construct, has high construction efficiency, high support strength, and strong safety and reliability.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel, comprising the following steps: S1, anchor hole drilling operation; S2, expanding the bottom of the anchor hole; S3, filling the self-expanding enlarged head anchor rod into the enlarged anchor hole; S4, performing grouting and sealing operation on the opening of the anchor hole; S5. Carry out grouting and anchoring operations inside the anchor hole.

[0006] The self-expanding enlarged head anchor in step S3 includes an anchor body with a central channel, a corresponding mounting hole is opened in the radial direction at the front end of the anchor body, the size of the mounting hole in the axial length direction of the anchor is larger than the size of the mounting hole in the radial direction of the anchor body, a pin is passed through the mounting hole along the radial direction of the anchor, both ends of the pin extend out of the anchor body, a left extension piece located on the left side of the anchor body and a right extension piece located on the right side of the anchor body are fixedly connected at both ends of the pin, a torsion spring for driving the pin to rotate is sleeved on the pin, and an expansion switch is provided on the left extension piece between the outer circle of the anchor body.

[0007] The deployment switch includes a convex oblique block fixed on the left extension piece, and the outer circle of the anchor rod body is provided with an oblique groove matching with the convex oblique block. The direction from the bottom of the oblique groove to the groove opening is an acute angle with the center line of the anchor rod body, and the direction from the bottom of the oblique groove to the groove opening is from front to back. When the convex oblique block is assembled in the oblique groove, the pin shaft is located at the front end of the mounting hole.

[0008] A plug hole is radially arranged on the pin shaft, one end of the torsion spring is inserted into the plug hole, and the other end of the torsion spring is pressed against the inner wall of the central channel of the anchor rod body.

[0009] The left extension piece and the right extension piece have the same structure and are symmetrically arranged about the center line of the pin shaft. The left extension piece and the right extension piece are both semicircular tubes. The inner diameters of the left extension piece and the right extension piece are equal to the outer diameter of the anchor rod body. The rear end of the left extension piece is fixedly connected to the two ends of the pin shaft through a left connecting plate, and the front end of the right extension piece is fixedly connected to the two ends of the pin shaft through a right connecting plate. The length of the left extension piece is greater than the distance from the front end of the anchor rod body to the pin shaft.

[0010] The left extension piece, the right extension piece, the left connecting plate and the right connecting plate are made of a round tube, a through hole is opened between the left connecting plate and the right connecting plate, both ends of the pin shaft extend into the pin hole, and limiting caps are fixed at both ends of the pin shaft.

[0011] Step S1 specifically includes: using a drilling rig to connect an ordinary drill rod, connecting an ordinary drill bit to the front end of the ordinary drill rod, and starting the drilling rig to drill a hole into the surrounding rock at a specified position on the tunnel wall; Step S2 is specifically as follows: withdraw the drilling tool, remove the ordinary drill bit, connect the ordinary drill rod to the reamer, use the drilling rig to push the reamer to the bottom of the anchor hole for bottom reaming operation, and after the operation is completed, a wedge-shaped reaming cavity is formed at the bottom of the anchor hole.

[0012] Step S3 is specifically as follows: after the hole enlarging operation is completed, the reamer is withdrawn, and the left and right extension pieces of the self-expanding enlarged head anchor are fitted to the outer circle of the anchor body, the torsion spring is charged, and then the limit cap is driven to move forward, so that the pin shaft moves forward along the mounting hole to the front end of the mounting hole, at which time the convex inclined block on the left extension piece extends into the inclined groove of the outer circle of the anchor body; then the self-expanding enlarged head anchor is inserted from front to back into the anchor hole until the bottom, and when the front end of the left extension piece contacts the rock at the bottom of the anchor hole, a certain axial thrust is applied forward to the self-expanding enlarged head anchor, and the left expansion piece is pressed against the rock at the bottom of the anchor hole. The front end of the expansion piece is blocked by the rock at the bottom of the anchor hole, the left expansion piece moves backward, the driving pin moves backward in the safety hole, and the convex inclined block also moves downward with the left expansion piece. After the convex inclined block disengages from the inclined groove, the driving pin rotates under the action of the torsion stored in the torsion spring, and the pin drives the left and right expansion pieces to rotate until the lower end of the left expansion piece and the upper end of the right expansion piece both contact the outer circle of the anchor rod body and stop rotating. At this time, the left and right expansion pieces rotate to be perpendicular to the anchor rod body to form a T-shaped structure, and the left and right expansion pieces extend into the wedge-shaped expansion cavity.

[0013] Step S4 is specifically as follows: after the self-expanding enlarged head anchor is installed, a matching tray and nut are installed at the rear end of the anchor body, a grouting pipe is passed through the grouting hole reserved on the tray, and a grouting and sealing operation is performed at the opening of the anchor hole through the grouting pipe.

[0014] Step S5 is specifically as follows: after the grouting and sealing is completed, grouting is performed into the anchor hole through the rear port of the anchor body of the self-expanding enlarged head anchor, and the slurry is injected into the wedge-shaped enlarged hole cavity from the front port of the anchor body through the central channel, and the grouting and anchoring operation is completed according to the designed grouting time and grouting pressure.

[0015] By adopting the above technical solution, compared with the prior art, the present invention has the following technical effects: (1) Drilling is performed first and then expanding the hole. The reamer used for expanding the hole can be the internal reamer of the mining anchor hole disclosed in Patent No. 2017103893312. Then, the self-expanding enlarged head anchor rod is installed into the anchor hole. The left and right expansion parts are expanded outwards through axial thrust to form a T-shaped structure with the anchor rod body. After grouting and anchoring, a T-shaped stress state is finally achieved, thereby increasing the anchoring force of the anchoring system and improving the control effect of the tunnel surrounding rock.

[0016] (2) Both the left extension piece and the right extension piece are made of semicircular tubes, so that when they are installed into the anchor hole, the left extension piece and the right extension piece can fit the outer circle of the anchor rod body and can be easily inserted into the anchor hole. A torsion spring is arranged on the pin shaft, and the two ends of the torsion spring respectively form a torsion between the pin shaft and the anchor rod body. When the left extension piece and the right extension piece fit the outer circle of the anchor rod body, the torsion spring accumulates force, and the mounting hole is set as a long hole structure. When the pin shaft moves to the front end of the mounting hole, the convex inclined block just extends into the inclined groove to keep the left extension piece and the right extension piece in the same axial state as the anchor rod body. When the left extension piece is subjected to axial thrust, the pin shaft moves backward along the mounting hole, so that the convex inclined block is separated from the inclined groove, and the torsion of the torsion spring rotates the left extension piece and the right extension piece to a state perpendicular to the anchor rod body.

[0017] (3) The present invention is used in a tunnel with fractured surrounding rock. The left extension piece and the right extension piece are both semicircular tubes. The two are combined to form a complete circle. The two have the same stress area. After grouting and anchoring, the left extension piece is stressed on the inner concave surface, and the right extension piece is stressed on the outer convex surface. The two-dimensional planes of stress are the same. When the anchor rod body is pulled out under stress, the left extension piece and the right extension piece are opened and the contact parts with the anchor rod body and the connection parts with the pin shaft are stressed together, finally realizing a "T"-shaped stress state, thereby increasing the anchoring force of the anchoring system and improving the control effect of the tunnel surrounding rock.

[0018] In summary, the present invention is simple to operate, low in cost, and high in anchoring strength. It can effectively solve the problem that the diameter of the enlarged head of the ordinary enlarged head anchor rod in the bottom expansion and backfilling anchoring support is greatly affected by the diameter of the anchor hole, making it difficult to play the role of the enlarged head anchor rod and the strengthening support effect of the bottom expansion and backfilling anchoring. The present invention does not have high requirements on the diameter of the anchor hole, and can fully design the size of the expansion piece based on the size of the bottom expansion hole of the bottom expansion and backfilling, give full play to the role of the bottom expansion and backfilling anchoring, improve the anchoring force of the anchoring system, and enhance the stability of the anchoring system, which is of great significance to the safe and efficient mining and support of the mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a construction flow chart of the present invention; Figure 2 It is a three-dimensional structural diagram of the left extension piece and the right extension piece of the self-expanding enlarged head anchor in a closed state; Figure 3 It is a three-dimensional structural diagram of the left extension piece and the right extension piece of the self-expanding enlarged head anchor in the expanded state; Figure 4 yes Figure 2 A schematic cross-sectional view of the middle anchor body at the pin and torsion spring; Figure 5 It is a schematic diagram of the cooperation between the convex oblique block and the oblique groove on the left extension, and the pin shaft at the upper part of the mounting hole; Figure 6It is a schematic diagram showing that the pin on the left extension moves to the lower part of the mounting hole after the convex bevel block on the left extension is disengaged from the bevel groove. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0021] like Figure 1-Figure 6 As shown, a method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel of the present invention comprises the following steps: S1, anchor hole 1 drilling operation; S2, expanding the bottom of anchor hole 1; S3, loading the self-expanding enlarged head anchor rod 2 into the enlarged anchor hole 1; S4, performing grouting and sealing operation at the opening of the anchor hole 1; S5. Perform grouting and anchoring operations inside the anchor hole 1.

[0022] The self-expanding enlarged head anchor rod 2 in step S3 includes an anchor rod body 4 with a central channel 3, and a corresponding mounting hole 11 is opened in the radial direction at the front end of the anchor rod body 4, and the size of the mounting hole 11 in the axial length direction of the anchor rod is larger than the size of the mounting hole 11 in the radial direction of the anchor rod body 4, and a pin shaft 5 is passed through the mounting hole 11 along the radial direction of the anchor rod, and both ends of the pin shaft 5 extend out of the anchor rod body 4, and both ends of the pin shaft 5 are fixedly connected with a left extension piece 6 located on the left side of the anchor rod body 4 and a right extension piece 7 located on the right side of the anchor rod body 4, and two torsion springs 8 for driving the pin shaft 5 to rotate are sleeved on the pin shaft 5, and an expansion switch between the outer circle of the anchor rod body 4 is provided on the left extension piece 6.

[0023] The deployment switch includes a convex beveled block 9 fixed on the left extension piece 6, and an outer circle of the anchor rod body 4 is provided with an oblique groove 10 that cooperates with the convex beveled block 9. The direction from the bottom of the groove 10 to the notch is an acute angle with the center line of the anchor rod body 4. The direction from the bottom of the groove 10 to the notch is from front to back. When the convex beveled block 9 is assembled in the oblique groove 10, the pin shaft 5 is located at the front end of the mounting hole 11.

[0024] The pin shaft 5 is provided with an insertion hole 12 in the radial direction. One end of the torsion spring 8 is inserted into the insertion hole 12 , and the other end of the torsion spring 8 is pressed against the inner wall of the central channel 3 of the anchor rod body 4 .

[0025] The left extension piece 6 and the right extension piece 7 have the same structure and are symmetrically arranged about the center line of the pin shaft 5. The left extension piece 6 and the right extension piece 7 are both semicircular tubes. The inner diameters of the left extension piece 6 and the right extension piece 7 are equal to the outer diameter of the anchor rod body 4. The rear end of the left extension piece 6 is fixedly connected to the two ends of the pin shaft 5 through a left connecting plate 13, and the front end of the right extension piece 7 is fixedly connected to the two ends of the pin shaft 5 through a right connecting plate 14. The length of the left extension piece 6 is greater than the distance from the front end of the anchor rod body 4 to the pin shaft 5.

[0026] The left extension piece 6, the right extension piece 7, the left connecting plate 13 and the right connecting plate 14 are made of a round tube. A through hole is opened between the left connecting plate 13 and the right connecting plate 14. Both ends of the pin shaft 5 extend into the pin hole. Limiting caps 15 are fixed at both ends of the pin shaft 5.

[0027] Step S1 specifically includes: using a drilling rig to connect an ordinary drill rod 16, connecting an ordinary drill bit 17 to the front end of the ordinary drill rod 16, and starting the drilling rig to drill a hole into the surrounding rock at a specified position on the tunnel wall; Step S2 is specifically as follows: withdraw the drilling tool, remove the ordinary drill bit 17, connect the ordinary drill rod 16 to the reamer 18, use the drilling rig to push the reamer 18 (using the internal reamer of the mining anchor hole disclosed in Patent No. 2017103893312) to the bottom of the anchor hole 1 for bottom reaming operation. After the operation is completed, a wedge-shaped reaming cavity 19 is formed at the bottom of the anchor hole 1.

[0028] Step S3 is specifically as follows: after the hole enlarging operation is completed, the hole reamer 18 is withdrawn, and the left extension piece 6 and the right extension piece 7 of the self-expanding enlarged head anchor rod 2 are fitted to the outer circle of the anchor rod body 4, the torsion spring 8 is charged, and then the limit cap 15 is driven to move forward, so that the pin shaft 5 moves forward along the mounting hole 11 to the front end of the mounting hole 11, and at this time, the convex inclined block 9 on the left extension piece 6 extends into the inclined groove 10 of the outer circle of the anchor rod body 4; then the self-expanding enlarged head anchor rod 2 is inserted from front to back into the anchor hole 1 until the bottom, and when the front end of the left extension piece 6 contacts the rock at the bottom of the anchor hole 1, a certain axial thrust is applied forward to the self-expanding enlarged head anchor rod 2, and the left expansion piece 6 is pressed against the rock at the bottom of the anchor hole 1. The front end of the expansion piece 6 is blocked by the rock at the bottom of the anchor hole 1, and the left expansion piece 6 moves backward, driving the pin shaft 5 to move backward in the safety hole, and the convex inclined block 9 also moves downward with the left expansion piece 6. After the convex inclined block 9 disengages from the inclined groove 10, under the action of the torsion force stored in the torsion spring 8, the driving pin shaft 5 rotates, and the pin shaft 5 drives the left expansion piece 6 and the right expansion piece 7 to rotate until the lower end of the left expansion piece 6 and the upper end of the right expansion piece 7 are in contact with the outer circle of the anchor rod body 4 and stop rotating. At this time, the left expansion piece 6 and the right expansion piece 7 rotate to be perpendicular to the anchor rod body 4 to form a T-shaped structure, and the left expansion piece 6 and the right expansion piece 7 extend into the wedge-shaped expansion cavity 19.

[0029] Step S4 is specifically as follows: after the self-expanding enlarged head anchor rod 2 is installed, a matching tray 20 and nut are installed at the rear end of the anchor rod body 4, a grouting pipe 21 is passed through the grouting hole reserved on the tray 20, and a grouting and sealing operation is performed to the opening of the anchor hole 1 through the grouting pipe 21.

[0030] Step S5 is specifically as follows: after the grouting and sealing is completed, grouting is performed into the anchor hole 1 through the rear port of the anchor body 4 of the self-expanding enlarged head anchor 2, and the slurry is injected into the wedge-shaped expansion cavity 19 from the front port of the anchor body 4 through the central channel 3, and the grouting and anchoring operation is completed according to the designed grouting time and grouting pressure. The above embodiments illustrate the basic principles and features of the present invention, but the above only illustrates the preferred embodiments of the present invention and is not limited to the embodiments. Under the inspiration of this patent, a person skilled in the art can make many forms of deformation and improvement without departing from the scope of protection of the present invention and the claims, which are all within the protection scope of the present invention. Therefore, the patent and protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel, characterized in that: The following steps are involved: S1, anchor hole drilling operation; S2, expanding the bottom of the anchor hole; S3, filling the self-expanding enlarged head anchor rod into the expanded anchor hole; S4, performing grouting and sealing operation on the opening of the anchor hole; S5. Carry out grouting and anchoring operations inside the anchor hole.

2. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 1, characterized in that: The self-expanding enlarged head anchor in step S3 includes an anchor body with a central channel, a corresponding mounting hole is opened in the radial direction at the front end of the anchor body, the size of the mounting hole in the axial length direction of the anchor is larger than the size of the mounting hole in the radial direction of the anchor body, a pin is passed through the mounting hole along the radial direction of the anchor, both ends of the pin extend out of the anchor body, a left extension piece located on the left side of the anchor body and a right extension piece located on the right side of the anchor body are fixedly connected at both ends of the pin, a torsion spring for driving the pin to rotate is sleeved on the pin, and an expansion switch is provided on the left extension piece between the outer circle of the anchor body.

3. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 2, characterized in that: The deployment switch includes a convex oblique block fixed on the left extension piece, and the outer circle of the anchor rod body is provided with an oblique groove matching with the convex oblique block. The direction from the bottom of the oblique groove to the groove opening is an acute angle with the center line of the anchor rod body, and the direction from the bottom of the oblique groove to the groove opening is from front to back. When the convex oblique block is assembled in the oblique groove, the pin shaft is located at the front end of the mounting hole.

4. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 3, characterized in that: A plug hole is radially arranged on the pin shaft, one end of the torsion spring is inserted into the plug hole, and the other end of the torsion spring is pressed against the inner wall of the central channel of the anchor rod body.

5. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 4, characterized in that: The left extension piece and the right extension piece have the same structure and are symmetrically arranged about the center line of the pin shaft. The left extension piece and the right extension piece are both semicircular tubes. The inner diameters of the left extension piece and the right extension piece are equal to the outer diameter of the anchor rod body. The rear end of the left extension piece is fixedly connected to the two ends of the pin shaft through a left connecting plate, and the front end of the right extension piece is fixedly connected to the two ends of the pin shaft through a right connecting plate. The length of the left extension piece is greater than the distance from the front end of the anchor rod body to the pin shaft.

6. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 5, characterized in that: The left extension piece, the right extension piece, the left connecting plate and the right connecting plate are made of a round tube, a through hole is opened between the left connecting plate and the right connecting plate, both ends of the pin shaft extend into the pin hole, and limiting caps are fixed at both ends of the pin shaft.

7. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 6, characterized in that: Step S1 specifically includes: using a drilling rig to connect an ordinary drill rod, connecting an ordinary drill bit to the front end of the ordinary drill rod, and starting the drilling rig to drill a hole into the surrounding rock at a specified position on the tunnel wall; Step S2 is specifically as follows: withdraw the drilling tool, remove the ordinary drill bit, connect the ordinary drill rod to the reamer, use the drilling rig to push the reamer to the bottom of the anchor hole for bottom reaming operation, and after the operation is completed, a wedge-shaped reaming cavity is formed at the bottom of the anchor hole.

8. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 7, characterized in that: Step S3 is specifically as follows: after the hole enlarging operation is completed, the reamer is withdrawn, and the left and right extension pieces of the self-expanding enlarged head anchor are fitted to the outer circle of the anchor body, the torsion spring is charged, and then the limit cap is driven to move forward, so that the pin shaft moves forward along the mounting hole to the front end of the mounting hole, at which time the convex inclined block on the left extension piece extends into the inclined groove of the outer circle of the anchor body; then the self-expanding enlarged head anchor is inserted from front to back into the anchor hole until the bottom, and when the front end of the left extension piece contacts the rock at the bottom of the anchor hole, a certain axial thrust is applied forward to the self-expanding enlarged head anchor, and the left expansion piece is pressed against the rock at the bottom of the anchor hole. The front end of the expansion piece is blocked by the rock at the bottom of the anchor hole, the left expansion piece moves backward, the driving pin moves backward in the safety hole, and the convex inclined block also moves downward with the left expansion piece. After the convex inclined block disengages from the inclined groove, the driving pin rotates under the action of the torsion stored in the torsion spring, and the pin drives the left and right expansion pieces to rotate until the lower end of the left expansion piece and the upper end of the right expansion piece both contact the outer circle of the anchor rod body and stop rotating. At this time, the left and right expansion pieces rotate to be perpendicular to the anchor rod body to form a T-shaped structure, and the left and right expansion pieces extend into the wedge-shaped expansion cavity.

9. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 8, characterized in that: Step S4 is specifically as follows: after the self-expanding enlarged head anchor is installed, a matching tray and nut are installed at the rear end of the anchor body, a grouting pipe is passed through the grouting hole reserved on the tray, and a grouting and sealing operation is performed at the opening of the anchor hole through the grouting pipe.

10. The method for installing and anchoring a self-expanding enlarged head anchor rod for supporting a cracked surrounding rock tunnel according to claim 9, characterized in that: Step S5 is specifically as follows: after the grouting and sealing is completed, grouting is performed into the anchor hole through the rear port of the anchor body of the self-expanding enlarged head anchor, and the slurry is injected into the wedge-shaped enlarged hole cavity from the front port of the anchor body through the central channel, and the grouting and anchoring operation is completed according to the designed grouting time and grouting pressure.

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