Anchor rod for supporting broken belt and its process method

Abstract

The present invention provides an anchor rod and a process method for supporting a broken zone, comprising a rod body, a plug is inserted into the rear side of the rod body, the rod body is a hollow structure, the rod body has a pipe seam arranged axially along the axial surface consistent with the length of the rod body, and the surface of the rod body has a circular hole. The rod body of the present invention adopts a micro-expansion self-compacting steel tube concrete structure, the annular constraint effect of the anchor rod body on the concrete and the joint force of the rod body and the concrete material significantly improve the mechanical properties of the anchor rod support structure, and the integrity and strength of the broken rock mass can be enhanced by pouring concrete into the broken zone through the rod body, giving full play to the self-supporting ability of the rock mass, and solving the engineering practice problems of low safety of the current broken zone support grouting anchor rod and the inability to give full play to the internal self-stabilizing ability of the rock mass.

Description

Technical Field

[0001] The invention relates to an anchor rod for supporting a broken zone and a process method thereof. Background Art

[0002] The broken zone refers to the area where the mechanical strength of the rock mass is low due to the development of weak structural surfaces such as joints and fissures inside the rock mass during the formation and development of the geological body. The support construction of underground projects crossing the broken zone is a key control link in the construction process. The quality of support is directly related to the safety of the excavation working face and the progress of the project. Due to the limited working space underground, the safety of broken zone support is the primary factor that engineering and technical personnel must face and consider.

[0003] According to relevant domestic and foreign literature, the current tunneling construction in the broken zone mainly adopts the anchor spraying process, which combines the application of traditional anchor rods and supports the surface of the broken zone tunnel by spraying concrete. There are mainly the following problems:

[0004] (1) It is impossible to increase the internal strength of the broken rock mass. Practical monitoring results show that shotcrete can reinforce the surface of the rock mass and improve the stress conditions on the surface of the tunnel rock mass, but it does not improve the stress state inside the broken rock mass and cannot further exert the self-supporting capacity of the rock mass. Furthermore, the safety accident of roof collapse in the broken zone shows that the anchor spraying process of surface shotcrete can easily make it impossible for the working face operators to find the safety hazards of the tunnel roof in time.

[0005] (2) Anchor rods in underground projects are rusted and corroded. Common anchor rods in underground projects have a short service life due to the humid underground environment and the fact that groundwater is often rich in metal ions. The mechanical properties of the anchor support structure in underground projects fail in a very short time. At the same time, since underground anchor projects are concealed projects, it is difficult to detect anchor rods that have failed due to rust. Summary of the invention

[0006] The present invention improves the above-mentioned problem, that is, the technical problem to be solved by the present invention is that the current broken zone support grouting anchor rods have low safety and cannot exert the internal self-stabilizing ability of the rock mass.

[0007] The specific implementation scheme of the present invention is: an anchor rod for supporting a broken zone, comprising a rod body, a plug is inserted into the rear side of the rod body, the rod body is a hollow structure, the rod body has a pipe seam arranged axially along the axial surface consistent with the length of the rod body, and the rod body surface has a circular hole.

[0008] Furthermore, there are multiple groups of circular holes along the length direction of the rod body, and each group of circular holes has three circular holes, which are respectively arranged on both sides of the pipe seam and on the side facing it.

[0009] Furthermore, a tray is sleeved on the outside of the supporting end of the rod body, and an annular steel bar is provided on the outside of the tray to limit the tray, and the annular steel bar is welded to the rod body.

[0010] Furthermore, the plug is hollow inside, has a concrete injection port at the outer end, has a nozzle connected to the inner cavity at the end inserted into the anchor rod, and the inner wall of the rod body and the surface of the plug have matching grooves and protrusions.

[0011] Furthermore, the outer wall of the plug has an air guide groove arranged along the axial direction of the anchor rod, and the cross-section of the air guide groove is circular.

[0012] Furthermore, the inner wall of the plug is provided with a cross-sectional guide groove along the length direction, and the nozzle is a cone-shaped nozzle formed by shrinking the inner end of the plug entering the anchor rod toward the middle.

[0013] Furthermore, the plug is made of rubber, and the tray is a square steel plate.

[0014] Furthermore, the plug has a length of 15 to 20 cm and a wall thickness of 4 to 5 mm.

[0015] The present invention also includes a process for supporting a broken zone, characterized in that it includes using the anchor rod for supporting a broken zone as claimed in claim 6, and the specific steps are as follows:

[0016] (1) When working, first evaluate the rock mass quality according to the degree of development of the fracture zone, determine the support position, mark the anchor installation position, and then use the anchor drill to drill the anchor hole. The anchor should be 0.1 to 0.2 m longer than the anchor rod body;

[0017] (2) Clean the anchor hole, then push the full length of the anchor rod into the anchor hole. The pressure of the broken zone on the rod body can shrink the pipe seam, and the length of the pipe seam is consistent with the length of the rod body.

[0018] (3) A tray is pre-set on the supporting end of the anchor rod, and a round steel bar is wrapped around one end of the anchor rod body and welded to form the initial anchoring prestress and increase the effective support range;

[0019] (4) A plug is installed by pressing into the supporting end of the anchor rod, and then a pouring conduit for pouring cement is inserted through the plug. The pouring is carried out in two steps. First, the pouring conduit is inserted into the bottom of the anchor rod through the nozzle, and cement is pumped into the pouring conduit through the grouting equipment to start the first step of low-pressure pouring with a pressure of 0.5 to 0.8 MPa. During the pouring process, the pouring conduit is slowly withdrawn until the full length of the anchor rod is densely poured, and then the pouring conduit and the plug are connected with a clip or a flange fixing clamp to carry out pressurized pouring.

[0020] (5) During the pouring process, the self-compacting micro-expansive concrete is evenly filled into the gaps between the rock and soil in the broken zone through the circular holes to form a grouting body.

[0021] Furthermore, the pressure used in the first step of low-pressure pouring is 0.5-0.8 MPa, and the pressure used in the second step of pressurized pouring is 1.5-2.5 MPa.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts a new grouting anchor structure to form a micro-expansion self-compacting steel tube concrete structure, the circumferential constraint effect of the anchor rod body on the concrete and the joint force of the rod body and the concrete material significantly improve the mechanical properties of the anchor support structure. In addition, under the action of pressurized pouring, the concrete fills the joints and fissures of the broken zone, enhances the integrity and strength of the broken rock mass, and gives full play to the self-supporting capacity of the rock mass. It solves the engineering practice problem that the current broken zone support grouting anchor has low safety and cannot give full play to the internal self-stabilizing capacity of the rock mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the construction status of the present invention.

[0024] Figure 2 It is a schematic diagram of the rod body with a pipe seam on one side of the present invention.

[0025] Figure 3 The rod body of the present invention corresponds to Figure 2 Rear schematic.

[0026] Figure 4 It is a schematic diagram of the matching structure of the plug and the rod body of the present invention.

[0027] Figure 5 It is a schematic diagram of the cross-sectional structure of the plug and the rod body of the present invention.

[0028] In the figure: 10-rod body, 110-pipe seam, 120-circular hole, 130-protrusion, 20-plug, 210-concrete injection port, 220-nozzle, 230-groove, 240-air guide groove, 250-guide groove, 30-tray, 40-annular steel bar, 50-grouting equipment, 510-casting conduit, 520-grouting body, 530-rock fracture zone. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figures 1 to 5As shown, an anchor rod for supporting a broken zone includes a rod body 10, a plug 20 is inserted into the rear side of the rod body 10, the rod body 10 is a hollow structure, and the rod body 10 has a pipe seam 110 arranged axially along the axial surface consistent with the length of the rod body, and the rod body surface has a circular hole 120.

[0031] In this embodiment, the circular holes 120 are provided in a plurality of groups along the length direction of the rod body, and each group of circular holes has three circular holes, which are respectively arranged on both sides of the pipe seam and on the opposite side.

[0032] In this embodiment, a tray 30 is sleeved on the outside of the supporting end of the rod body, and an annular steel bar 40 is provided on the outside of the tray to limit the tray. The annular steel bar 40 is welded to the outer surface of the rod body 10 .

[0033] In this embodiment, the plug 20 is hollow inside, and has a concrete injection port 210 at the outer end of the plug. The end inserted into the anchor rod has a nozzle 220 connected to the inner cavity. The inner wall of the rod body 10 and the surface of the plug 20 have matching grooves 230 and protrusions 130. The outer wall of the plug has an air guide groove 240 arranged along the axial direction of the anchor rod, and the cross-section of the air guide groove is circular.

[0034] In the present embodiment, in order to improve the fit between the plug and the anchor rod, the inner wall of the rod body 10 and the surface of the plug 20 have mutually fitting grooves 230 and protrusions 130. The protrusions and grooves 230 may be provided in multiple corresponding locations, but the air guide groove 240 is avoided to ensure the smooth flow of the air guide groove 250. In the present embodiment, the plug is made of rubber, so as to avoid rust and facilitate deformation of the groove to be inserted into the anchor rod.

[0035] In this embodiment, the inner wall of the plug 20 is provided with a cross-sectional guide groove 250 along the length direction, and the cross-section of the guide groove is semicircular. The nozzle 220 is the inner end of the plug entering the anchor rod and is narrowed toward the middle to form a cone.

[0036] In this embodiment, the plug is made of rubber material, so as to avoid rusting, and the tray is a square steel plate.

[0037] In this embodiment, the plug has a length of 15 to 20 cm and a wall thickness of 4 to 5 mm.

[0038] During the work, firstly, according to the development degree of the broken zone, the rock mass quality is re-evaluated, the support position is determined, and the anchor installation position is marked. Then, the anchor hole is drilled with an anchor drill. The anchor should be 0.1-0.2m longer than the anchor rod body. The anchor hole is cleaned, and then the full length of the anchor rod body is pushed into the anchor hole. The pressure of the broken zone on the rod body can shrink the pipe seam 110, and the pipe seam length is consistent with the rod body length.

[0039] The diameter of the anchor hole is D1, the diameter of the anchor is D2, and the pipe seam width satisfies the following relationship: π(D2-D1)≤L;

[0040] The supporting end of the anchor rod is preliminarily covered with a tray 30, and the round steel bar 40 surrounds one end of the anchor rod body and is formed by fusion welding to form the initial anchoring prestress and increase the effective support range.

[0041] A plug 20 is pressed into the supporting end of the anchor rod and installed, and then a pouring conduit 510 for pouring cement is extended into the plug. The pouring is carried out in two steps. First, the pouring conduit is extended into the bottom of the anchor rod body, and pressure is pumped into the pouring conduit 510 through the grouting equipment 50 to start the first step of low-pressure pouring with a pressure of 0.5-0.8 MPa. During the pouring process, the pouring conduit is slowly withdrawn until the full length of the anchor rod body is densely poured, and then the pouring conduit and the plug are connected with a clip or a flange to perform pressurized pouring.

[0042] During the pouring process, the self-compacting micro-expansive concrete is uniformly filled into the gaps between the rock and soil in the broken zone through the circular holes 120 to form a grouting body 520, thereby improving the mechanical properties of the rock and soil.

[0043] The outer wall of the plug has an air guide groove 240 arranged along the axial direction of the anchor rod, which can ensure the smooth entry of the plug and the exhaust of the anchor rod during the pouring process. The guide groove 250 of the plug is arranged on the inner wall of the plug and has a semicircular cross-section.

[0044] The guide groove 250 is used to form a stable fluid and to form an extrusion force on the side wall of the anchor rod body 10 when pouring the self-compacting micro-expansive concrete to prevent the plug from falling off or squeezing out. The nozzle 220 is conical and points to the front end of the anchor rod body to prevent the self-compacting micro-expansive concrete from flowing back.

[0045] After pouring, the support structure forms a micro-expansion self-compacting steel tube concrete. Due to the effect of the seam, the circumferential constraint of the anchor rod body on the concrete and the joint force of the rod body and concrete materials, the mechanical properties of the anchor support structure are significantly improved. On the other hand, under the action of pressurized pouring, the concrete fills the joints and fissures in the broken zone, enhances the integrity and strength of the broken rock mass, and gives full play to the self-supporting capacity of the rock mass.

[0046] A specific implementation scheme is provided below:

[0047] A tunnel for a metal mine development project, with a tunnel section of 4×4.5m 2 (width × height), a long-distance broken zone was encountered during the excavation process, and the excavation tunnel length in the broken zone was 60 to 80 meters. The broken zone has developed joints and fissures, and the hydraulic recharge is mainly fissure water. The water inflow at the working face is 2 to 5 m 3 / h (24 hours a day, average of 3 measurements).

[0048] 1. According to the geological data provided by the mine, advance water exploration is carried out when it is 15 to 20 meters close to the broken zone. The water inflow is predicted based on the water exploration results of the working face to determine the degree of development of the broken zone.

[0049] 2. Re-evaluate the rock mass quality according to the degree of development of the broken zone, determine the following distance between the support and the working face to be 0.5m, and use short excavation and short support.

[0050] 3. After marking the anchor installation position, first use an anchor drill to drill the anchor hole. The hole depth is 2.0 to 2.5 meters, and the anchor is also over-deep with a rod length of 0.1 to 0.2 meters.

[0051] 4. Use high-pressure air to clean the anchor hole, and use a small-diameter rod to carefully remove the gravel in the hole to complete the hole cleaning operation.

[0052] 5. Cooperate with the installation of the anchor rod body and tray, and use the hydraulic arm of the anchor rod trolley to push the entire length of the anchor rod body into the anchor rod hole.

[0053] (1) The anchor rod consists of three parts: metal rod body, tray and plug.

[0054] (2) The anchor rod is made of metal and is a hollow steel pipe with a wall thickness of 2 to 3 mm and a length of 2.0 to 2.5 m.

[0055] (3) A pipe seam with a width of L is reserved along the steel pipe, and the length of the pipe seam is consistent with the length of the rod body. The diameter of the blasthole is D1, the diameter of the anchor rod is D2, and the width of the pipe seam satisfies the following relationship: π(D2-D1)≤L.

[0056] (4) One end of the rod body is the support end, which is formed by welding a round steel bar with a diameter of 8 to 10 mm around one end of the anchor rod body. The support end is used to lock the tray, form the initial anchor prestress, and increase the effective support range.

[0057] (5) Circular holes are arranged in the other three directions symmetrical to the pipe seam around the anchor rod body. The spacing between the circular holes in each direction is 40m, and the diameter of the circular holes is D3. The circular holes in each direction are arranged alternately. No circular holes are arranged within 0.3~0.5m from the anchor support end.

[0058] (6) The pallet is made of metal, a square steel plate with a thickness of 10-12 mm and a side length of 15 x 15 cm. 2 (length x width).

[0059] 6. Press and install the plug at the anchor support end:

[0060] (1) The plug is made of rubber, hollow flexible synthetic rubber, integrally molded, 15 to 20 cm long, with a diameter the same as the inner diameter of the anchor rod, a matching tolerance of 1 to 2 mm, and a wall thickness of 4 to 5 mm.

[0061] (2) The plug includes a nozzle, an air guide groove, a flow guide groove, and a connecting section.

[0062] (3) The nozzle is conical and points toward the front end of the anchor rod to prevent the backflow of self-compacting micro-expansive concrete.

[0063] (4) The air flow lines of the air guide groove are arranged on the outer walls around the plug. The air guide groove is a cylindrical groove with a radius of R1. Practice has shown that the optimal value is 2 to 3 mm.

[0064] (5) The guide groove is arranged on the inner wall of the plug and has a semicircular cross section. The guide groove is used to form a stable fluid and to exert a squeezing force on the side wall of the anchor rod when pouring the self-compacting micro-expansive concrete to prevent the plug from falling off or being squeezed out.

[0065] (6) The connection section is used to connect the conduit and the plug with a clip or flange to perform pressure pouring at the end of pouring of self-compacting concrete. Two annular matching grooves are arranged in the connection section.

[0066] 7. Mix and match self-compacting micro-expansive concrete, which requires low slump and self-flowing conditions. The aggregate is fine sand, and the other main ingredients are water glass, fly ash, early strength cement, and HCSA expansion agent. Practice has shown that when the volume ratio of cement slurry to water glass is about 1:0.4, good pouring conditions can be met.

[0067] 8. Inject and pour concrete in two steps. First, extend the pouring conduit into the bottom of the anchor rod body, and start the first step of low-pressure pouring, with a pressure of 0.5-0.8MPa; during the pouring process, slowly withdraw the pouring conduit until the full length of the anchor rod body is densely poured. Then connect the pouring conduit and the plug with a buckle or flange fixing clamp, and perform pressurized pouring in the second step, with a pressure of 1.5-2.5MPa.

[0068] 9. After the pressure pouring starts, observe the changes in the indication of the pressure gauge on the pressure pump. When the pressure gauge pressure gradually increases to the designed pressure pouring pressure, and remains stable for 3 minutes without obvious pressure drop, stop the pressure pouring.

[0069] 10. After pouring, the support structure forms a micro-expansion self-compacting steel tube concrete. The circumferential constraint of the anchor rod body on the concrete and the joint force of the rod body and concrete materials significantly improve the mechanical properties of the anchor support structure. On the other hand, under the action of pressurized pouring, the concrete fills the joints and cracks in the broken zone, enhances the integrity and strength of the broken rock mass, and gives full play to the self-supporting capacity of the rock mass.

[0070] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integrated molding using a casting process) (except when it is obviously impossible to use an integrated molding process).

[0071] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0072] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. An anchor rod for supporting a broken zone, characterized in that: It comprises a rod body, a plug is inserted into the rear side of the rod body, the rod body is a hollow structure, the axial surface of the rod body has a pipe slit arranged along the axial direction in accordance with the length of the rod body, and the surface of the rod body has a circular hole; The plug is hollow inside, has a concrete injection port at the outer end, has a nozzle connected to the inner cavity at the end inserted into the anchor rod, and has grooves and protrusions matching each other on the inner wall of the rod body and the surface of the plug; The inner wall of the plug is provided with a cross-sectional guide groove along the length direction, the cross-section of the guide groove is semicircular, and the nozzle is the inner end of the plug entering the anchor rod, which is narrowed toward the middle to form a cone shape.

2. The anchor rod for supporting a broken zone according to claim 1, characterized in that: There are multiple groups of circular holes along the length direction of the rod body, and each group of circular holes has three circular holes, which are respectively arranged on both sides of the pipe seam and one side facing the pipe seam.

3. The anchor rod for supporting a broken zone according to claim 1, characterized in that: A tray is sleeved on the outside of the supporting end of the rod body, and an annular steel bar is provided on the outside of the tray for limiting the position of the tray, and the annular steel bar is welded to the rod body.

4. The anchor rod for supporting a broken zone according to claim 1, characterized in that: The outer wall of the plug has an air guide groove arranged along the axial direction of the anchor rod.

5. The anchor rod for supporting a broken zone according to claim 3, characterized in that: The plug is made of rubber, and the tray is a square steel plate.

6. The anchor rod for supporting a broken zone according to claim 1, characterized in that: The plug has a length of 15 to 20 cm and a wall thickness of 4 to 5 mm.

7. A process for supporting a broken zone, characterized in that: The method comprises utilizing the anchor rod for supporting a broken zone as claimed in claim 6, wherein the specific steps are as follows: (1) When working, first evaluate the rock mass quality according to the degree of development of the broken zone, determine the support position, mark the anchor installation position, and then use the anchor drilling rig to drill the anchor hole. The depth of the anchor hole should exceed the length of the anchor rod by 0.1 to 0.2 m; (2) Clean the anchor hole, then push the full length of the anchor rod into the anchor hole. The pressure of the broken zone on the rod body can shrink the pipe seam, and the length of the pipe seam is consistent with the length of the rod body. (3) A tray is pre-set on the supporting end of the anchor rod, and a round steel bar is wrapped around one end of the anchor rod body and welded to form the initial anchoring prestress and increase the effective support range; (4) A plug is installed by pressing into the supporting end of the anchor rod, and then a pouring conduit for pouring cement is inserted through the plug. The pouring is carried out in two steps. First, the pouring conduit is inserted into the bottom of the anchor rod through the nozzle, and cement is pumped into the pouring conduit through the grouting equipment to start the first step of low-pressure pouring with a pressure of 0.5 to 0.8 MPa. During the pouring process, the pouring conduit is slowly withdrawn until the full length of the anchor rod is densely poured, and then the pouring conduit and the plug are connected with a buckle or flange fixing clamp, and the second step of pressurized pouring is carried out. (5) During the pouring process, the self-compacting micro-expansive concrete is evenly filled into the gaps between the rock and soil in the broken zone through the circular holes to form a grouting body.

8. A process for supporting a broken zone according to claim 7, characterized in that: The pressure used in the second step of pressurized pouring is 1.5~2.5Mpa.

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