Variable-resistance anchor cable structure and anchoring method

Abstract

The invention relates to the field of rock mass anchoring, in particular to a variable-resistance anchor cable structure and an anchoring method. The anchor cable comprises a sleeve, a blocking body, an anchor cable body and a pre-tightening assembly. The sleeve comprises a limiting part and a first threaded connection part; the inner circumference of the limiting part is gradually reduced from one end of the limiting part to the other end of the limiting part along the central axis of the limiting part; a plurality of annular protrusions with the inner diameters gradually reduced are arranged on the inner surface of the limiting part at intervals, and the first threaded connecting part communicates with the end, with the largest inner circumference, of the limiting part. The pre-tightening assembly is in threaded connection with the first threaded connection part; the blocking body is arranged in the limiting part, and a limiting bulge is arranged on the blocking body; the limiting protrusion can be connected with the annular protrusion in an abutting mode. The blocking body is detachably connected with the anchor cable body. In this way, the problem that anchor cable supporting is prone to failure due to the fact that deformation becomes larger and larger after rock stress balance is broken is solved.

Description

Technical Field

[0001] The invention relates to the field of rock mass anchoring, and in particular to a variable resistance anchor cable structure and an anchoring method. Background Art

[0002] As the main fossil energy source in my country, coal provides an important guarantee for my country's industrialization process. Most of my country's coal is stored in rock strata, and coal is mostly mined underground.

[0003] During the coal mining process, the tunnel roof needs to be supported by anchor cables. The traditional anchor cable body uses prestressed steel strands, one end of which is fixed to the roof rock wall and the other end is anchored in the stable rock formation through an anchoring agent, providing radial and tangential constraints, improving the horizontal bearing capacity of the rock formation, and achieving the purpose of controlling the deformation and collapse of the tunnel roof.

[0004] As the mining depth increases, the disturbance to the rock strata also increases, and the possibility of rock deformation also increases. The deformation of the rock mass is usually additive. After the force balance of the deformed rock mass is broken, its subsequent deformation is likely to become larger and larger, which can easily lead to the failure of the anchor support. Summary of the invention

[0005] In order to solve the problem that the deformation of rock mass becomes larger and larger after the force balance is broken, which easily leads to the failure of anchor cable support, the present invention provides a variable resistance anchor cable structure and an anchoring method.

[0006] In a first aspect, this embodiment provides a variable resistance anchor cable structure, including:

[0007] A sleeve, a blocking body, an anchor body, and a pre-tightening assembly; the sleeve includes a limiting portion and a first threaded connection portion; the inner circumference of the limiting portion gradually decreases from one end of the limiting portion to the other end of the limiting portion along the central axis of the limiting portion; a plurality of annular protrusions with gradually decreasing inner diameters are arranged at intervals on the inner surface of the limiting portion, and the first threaded connection portion is connected to the end portion at the largest point of the inner circumference of the limiting portion; the pre-tightening assembly is threadedly connected to the first threaded connection portion; the blocking body is arranged in the limiting portion, and a limiting protrusion is arranged on the blocking body; the limiting protrusion can abut against the annular protrusion; the blocking body and the anchor body are detachably connected.

[0008] In some embodiments, the outer circumference of the limiting portion gradually decreases from one end of the limiting portion to the other end of the limiting portion along the central axis of the limiting portion; the direction in which the inner circumference of the limiting portion gradually decreases is the same as the direction in which the outer circumference of the limiting portion gradually decreases; a second threaded connection portion is provided on the outer circumferential surface of one end of the limiting portion, and a third threaded connection portion is provided on the outer circumferential surface of the other end; the variable resistance anchor cable structure also includes a protective threaded tube, a bolt is provided on the inner circumferential surface of the protective threaded tube, and the protective threaded tube can be threadedly connected with the second threaded connection portion and the third threaded connection portion.

[0009] In some embodiments, the inner surface of the limiting portion between two adjacent annular protrusions is concave toward the outer circumferential surface of the limiting portion along the radial direction of the limiting portion to form a curved surface.

[0010] In some embodiments, the blocking body is in the shape of a cone; the limiting protrusion is arranged in a ring shape along the maximum outer circumference of the blocking body, and a conical hole is provided on the blocking body. The conical hole passes through the blocking body along the central axis of the blocking body, and the maximum end of the conical hole is located at the maximum end face of the blocking body. The blocking body is detachably connected to the anchor body through the conical hole.

[0011] In some embodiments, the taper of the tapered hole is equal to the taper of the blocking body.

[0012] In some embodiments, the anchor cable body includes an anchor rod, an anchor, and an anchor head; one end of the anchor rod is fixedly connected to the anchor head, and the other end is detachably fixedly connected to the anchor, and the length of the anchor rod is greater than the length of the limiting portion; the anchor is conical, and the taper of the anchor is equal to the taper of the conical hole; the conical surface of the anchor can be interference fit with the inner conical surface of the blocking body.

[0013] In some embodiments, the anchor head is cylindrical, and its diameter is larger than the diameter of the anchor rod and smaller than the maximum outer diameter of the limiting portion.

[0014] In some embodiments, the variable resistance anchor cable structure also includes a baffle plate, on which a fixed connection portion and a limiting through hole are provided, the fixed connection portion can be fixedly connected to the smallest end of the inner circumference of the limiting portion, and the diameter of the limiting through hole is larger than the diameter of the anchor rod.

[0015] In some embodiments, the pre-tensioning assembly includes a pre-tensioning bolt, a first gasket, a second gasket, and a pre-tensioning spring; the pre-tensioning bolt is detachably connected to the first gasket, the second gasket is coupled to the first threaded connection portion, and the pre-tensioning spring is arranged on the bolt between the first gasket and the second gasket.

[0016] In a second aspect, this embodiment provides a method for anchoring a variable resistance anchor cable, comprising the following steps:

[0017] S11: detachably connecting the blocking body to the anchor cable body;

[0018] S12: drilling a hole in the rock mass, inserting the anchor cable body into the hole, and fixing the anchor cable body in the hole with an anchoring resin;

[0019] S13: inserting the limiting part into the borehole, setting it apart from the rock mass, and leaving the first threaded connection part outside the borehole;

[0020] S14: Threading the pre-tightening assembly to the first threaded connection portion, and allowing the limiting protrusion to abut against the annular protrusion.

[0021] In order to solve the problem that the deformation of the rock mass becomes larger and larger after the force balance is broken, which easily leads to the failure of the anchor cable support, the present invention has the following advantages:

[0022] The inner circumference of the limiting part gradually decreases from one end of the limiting part to the other end of the limiting part along the central axis of the limiting part, and a plurality of annular protrusions with gradually decreasing inner diameters are arranged at intervals on the inner surface of the limiting part, and a limiting protrusion is arranged on the blocking body; the limiting protrusion can abut against the annular protrusion, and when the force balance of the rock mass is broken and the deformation becomes larger and larger, the tension on the anchor cable body continues to increase, and the blocking body moves the axial direction of the rock limiting part toward the minimum direction of the inner circumference of the limiting part, and the abutment force between the limiting protrusion and the annular protrusion will also become larger and larger, and the constant resistance is gradually increased to gradually increase the reaction force of the damaged surrounding rock. Under the premise of adapting to the deformation of the surrounding rock of the tunnel, the anchor cable structure will not fail due to constant resistance, and the broken surrounding rock can be better stabilized so that the broken surrounding rock is tightly clamped to form a stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an overall schematic diagram of a variable resistance anchor cable structure;

[0024] Figure 2 for Figure 1 Sectional view along the AA direction;

[0025] Figure 3 for Figure 1 Explosion diagram of

[0026] Figure 4 for Figure 2 A local enlarged schematic diagram of the middle A;

[0027] Figure 5 Schematic diagram of the structure of the sleeve in some embodiments;

[0028] Figure 6 for Figure 5 Cross-section along the middle BB direction;

[0029] Figure 7 It is a schematic diagram of the connection between the protection tube and the casing;

[0030] Figure 8 for Figure 7 Cross-section along the mid-CC direction;

[0031] Fig. 9 for Figure 6 A partial enlarged schematic diagram of point B in the middle;

[0032] Fig.10 for Figure 3 A partial enlarged schematic diagram of point C in the middle;

[0033] Fig.11 It is a schematic diagram of anchoring of a variable resistance anchor cable structure;

[0034] Fig.12 It is an overall schematic diagram of a variable resistance anchor cable structure in some embodiments.

[0035] In the figure: 10, sleeve; 11, limiting part; 12, first threaded connection part; 13, annular protrusion; 14, second threaded connection part; 15, third threaded connection part; 20, blocking body; 21, limiting protrusion; 22, tapered hole; 30, anchor cable body; 31, anchor rod; 32, anchor; 33, anchor head; 40, pre-tightening assembly; 41, pre-bolt; 42, first gasket; 43, second gasket; 44, pre-tightening spring; 45, numerical display column; 50, baffle; 51, fixed connection part; 52, limiting perforation; 60, protective tube; 70, rock mass; 80, anchoring resin. DETAILED DESCRIPTION

[0036] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0037] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0038] This embodiment discloses a variable resistance anchor cable structure, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Fig.11 As shown, including:

[0039] A sleeve 10, a blocking body 20, an anchor body 30, and a pre-tightening assembly 40; the sleeve 10 includes a limiting portion 11 and a first threaded connection portion 12; the inner circumference of the limiting portion 11 gradually decreases from one end of the limiting portion 11 to the other end of the limiting portion 11 along the central axis of the limiting portion 11; a plurality of annular protrusions 13 with gradually decreasing inner diameters are arranged at intervals on the inner surface of the limiting portion 11, and the first threaded connection portion 12 is connected to the end portion at the maximum point of the inner circumference of the limiting portion 11; the pre-tightening assembly 40 is threadedly connected to the first threaded connection portion 12; the blocking body 20 is arranged in the limiting portion 11, and a limiting protrusion 21 is arranged on the blocking body 20; the limiting protrusion 21 can abut against the annular protrusion 13; the blocking body 20 and the anchor body 30 are detachably connected.

[0040] In this embodiment, if Figure 1 , Figure 2 , Figure 4 , Figure 7 As shown, the anchor cable body 30 is anchored in the rock mass 70 by the anchoring resin 80. When the rock mass 70 is deformed, the anchor cable body 30 is subjected to a rightward pulling force, and the anchor cable body 30 pulls the blocking body 20 to the right. The limiting protrusion 21 on the blocking body 20 abuts against the annular protrusion 13 on the inner surface of the limiting portion 11, thereby hindering the deformation of the rock mass 70 and keeping the rock mass 70 in a force balance. When the force balance of the rock mass 70 is broken, the deformation becomes larger, and the pulling force to the right on the anchor cable body 30 also becomes larger, and the blocking body 20 is subjected to a larger pulling force. After the force is applied, the limiting protrusion 21 breaks away from the contact with the annular protrusion 13, moves axially along the limiting portion 11, and abuts against the next annular protrusion 13. As the inner diameter of the annular protrusion 13 gradually decreases, the abutment force between the annular protrusion 13 and the limiting protrusion 21 becomes larger and larger, so that the reverse force of the anchor cable body 30 on the rock mass 70 also increases as the deformation of the rock mass 70 increases, thereby being able to provide an anchoring force corresponding to the deformation of the rock mass 70, thereby further preventing further deformation of the rock mass 70 and ensuring the anchoring effect. In this embodiment, a limiting protrusion 21 is provided on the early blocking body 20; the limiting protrusion 21 can abut against the annular protrusion 13. When the force balance of the rock mass 70 is broken and the deformation becomes larger and larger, the anchor cable body 30 is subjected to increasing tension from the rock mass 70, and the blocking body 20 moves the axial direction of the rock limiting portion 11 toward the minimum direction of the inner circumference of the limiting portion 11. The abutment force between the limiting protrusion 21 and the annular protrusion 13 will also become larger and larger. The constant resistance is gradually increased to gradually increase the reaction force of the damaged surrounding rock. Under the premise of adapting to the deformation of the surrounding rock of the tunnel, the anchor cable structure will not fail due to constant resistance, and the broken surrounding rock can be better stabilized so that the broken surrounding rock is tightly clamped to form a stable structure.

[0041] In some embodiments, Figure 5 , Figure 6 , Figure 7 , Figure 8, Fig. 9 As shown, the outer circumference of the limiting portion 11 gradually decreases from one end of the limiting portion 11 to the other end of the limiting portion 11 along the central axis of the limiting portion 11; the direction in which the inner circumference of the limiting portion 11 gradually decreases is the same as the direction in which the outer circumference of the limiting portion 11 gradually decreases; the outer circumferential surface of one end of the limiting portion 11 is provided with a second threaded connection portion 14, and the outer circumferential surface of the other end is provided with a third threaded connection portion 15; the variable resistance anchor cable structure also includes a protective threaded tube, the inner circumferential surface of the protective threaded tube is provided with bolts, and the protective threaded tube can be threadedly connected with the second threaded connection portion 14 and the third threaded connection portion 15.

[0042] In this embodiment, after the protective threaded tube is threadedly connected with the second threaded connection part 14 and the third threaded connection part 15, a gap is formed between the protective tube 60 and part of the outer surface of the limiting part 11. The gap can play a role in that when the annular protrusion 13 on the inner surface of the limiting part 11 is subjected to too large abutment force by the limiting protrusion 21 on the blocking body 20, the limiting part 11 may bulge outward in its radial direction. The bulging part can be left in the gap without squeezing the rock mass 70, causing the rock mass 70 to break, and avoiding the force balance of the rock mass 70 to be broken. In this embodiment, the gap gradually increases along the axial direction of the limiting part 11 because during the tensile movement of the blocking body 20, the abutment force between the limiting protrusion 21 thereon and the annular protrusion 13 will become larger and larger, which is easy to cause the deformation of the limiting part 11 along its radial direction to become larger and larger. By setting the gap to gradually increase along the axial direction of the limiting part 11, the deformation of the limiting part 11 along its radial direction can be accommodated accordingly, thereby protecting the rock mass 70.

[0043] In some embodiments, Figure 6 As shown, the inner surface of the limiting portion 11 between two adjacent annular protrusions 13 is concave toward the outer circumferential surface of the limiting portion 11 along the radial direction of the limiting portion 11 to form a curved surface.

[0044] In this embodiment, the inner surface of the limiting portion 11 between two adjacent annular protrusions 13 is concave toward the outer circumferential surface of the limiting portion 11 in a radial manner along the limiting portion 11 to form a curved surface, so that the contact area between the inner surface of the limiting portion 11 and the upper limiting protrusion 21 of the blocking body 20 can be increased, and the pressure generated by the limiting portion 11 being subjected to the pressure of the limiting protrusion 21 can be reduced, thereby enhancing the compressive strength of the limiting portion 11, preventing it from being damaged easily, and ensuring that the sleeve 10 has a longer service life.

[0045] In some embodiments, Figure 2 , Figure 3As shown, the blocking body 20 is in the shape of a cone; the limiting protrusion 21 is arranged in a ring shape along the maximum outer circumference of the blocking body 20, and a conical hole 22 is arranged on the blocking body 20, and the conical hole 22 passes through the blocking body 20 along the central axis of the blocking body 20, and the maximum end of the conical hole 22 is located at the maximum end face of the blocking body 20, and the blocking body 20 is detachably connected to the anchor body 30 through the conical hole 22.

[0046] In this embodiment, the limiting protrusion 21 is arranged in a ring shape along the maximum outer circumference of the blocking body 20, and the tapered hole 22 penetrates the blocking body 20 along the central axis of the blocking body 20. The blocking body 20 is detachably connected to the anchor body 30 through the tapered hole 22. When the anchor body 30 applies a pulling force to the blocking body 20, the annular limiting protrusion 21 can have a more uniform contact surface with the annular protrusion 13 on the limiting portion 11, thereby making the annular protrusion 13 have a better blocking effect.

[0047] In some embodiments, Figure 3 , Figure 4 As shown, the taper of the tapered hole 22 is equal to the taper of the blocking body 20 .

[0048] In this embodiment, the taper of the tapered hole 22 is equal to that of the blocking body 20 , so that the wall thickness of the blocking body 20 can be consistent, so that when subjected to the tension of the anchor body 30 , it is not easy to generate local stress and cause local deformation, thereby enhancing the service life of the blocking body 20 .

[0049] In some embodiments, Figure 3 As shown, the anchor cable body 30 includes an anchor rod 31, an anchor 32, and an anchor head 33; one end of the anchor rod 31 is fixedly connected to the anchor head 33, and the other end is detachably fixedly connected to the anchor 32, and the length of the anchor rod 31 is greater than the length of the limiting portion 11; the anchor 32 is conical, and the taper of the anchor 32 is equal to the taper of the conical hole 22; the conical surface of the anchor 32 can be interference fit with the inner conical surface of the blocking body 20.

[0050] In this embodiment, the anchoring resin 80 anchors the anchor head 33 and the anchor rod 31 in the drilled hole of the rock mass 70, and the anchor 32 is conical, and the taper of the anchor 32 is equal to the taper of the conical hole 22; the conical surface of the anchor 32 can be interference fit with the inner conical surface of the blocking body 20, so that the anchor 32 and the blocking body 20 have a larger contact area, and the anchor 32 can be prevented from falling off the blocking body 20. At the same time, the parts of the blocking body 20 can be evenly pulled by the anchor 32 along its axial direction, thereby ensuring that the blocking body 20 is not easily deformed during the tension process, and ensuring that the limiting protrusion 21 thereon is always in good contact with the annular protrusion 13.

[0051] In some embodiments, Figure 2, Figure 3 , Fig.11 As shown, the anchor head 33 is cylindrical, and its diameter is larger than the diameter of the anchor rod 31 and smaller than the maximum outer diameter of the limiting portion 11 .

[0052] In this embodiment, if Fig.11 As shown, by setting the diameter of the anchor head 33 to be larger than the diameter of the anchor rod 31 and smaller than the maximum outer diameter of the limiting portion 11, the resistance to the anchor head 33 in the left direction can be increased, thereby preventing the anchor head 33 from sliding to the left under the action of the preload force component, thereby causing anchor failure.

[0053] In some embodiments, the variable resistance anchor cable structure also includes a baffle plate 50, on which a fixed connection portion 51 and a limiting through hole 52 are provided. The fixed connection portion 51 can be fixedly connected to the smallest end of the inner circumference of the limiting portion 11, and the diameter of the limiting through hole 52 is larger than the diameter of the anchor rod 31.

[0054] In this embodiment, if Figure 3 , Fig.10 , Fig.11 As shown, the anchor rod 31 passes through the limiting through-hole 52 through the fixed connection portion 51 and the minimum end of the inner circumference of the limiting portion 11. In the present embodiment, the gap between the anchor rod 31 and the limiting through-hole 52 is 0.6-1 mm, and the outer diameter of the baffle plate 50 is less than or equal to the diameter of the minimum outer circumference of the limiting portion 11. After the baffle plate 50 is fixedly connected to the limiting portion 11, it can prevent the anchoring resin 80 from entering the limiting portion 11 when the anchor rod 31 is fixed, and prevent the limiting portion 11 from being blocked by the anchoring resin 80. When the anchor rod 31 is subjected to tension, the limiting through-hole 52 can limit the displacement of the anchor rod 31 in the radial direction of the anchor rod 31, and avoid the anchor rod 31 from being displaced too much in its radial direction, causing the limiting protrusion 21 on the blocking body 20 to locally apply excessive pressure to the annular protrusion 13, thereby causing the limiting portion 11 to be locally deformed, causing the blocking body 20 to be out of contact with the limiting portion 11, and causing anchor failure. In some embodiments, a corresponding annular retaining ring (not shown in the figure) can be provided as needed. The inner diameter of the annular retaining ring is smaller than the minimum outer circumference of the blocking body 20. The annular retaining ring can be used to limit the position of the blocking body 20 and prevent the blocking body 20 from escaping from the limiting portion 11.

[0055] In some embodiments, the pre-tightening assembly 40 includes a pre-tightening bolt, a first gasket 42, a second gasket 43, and a pre-tightening spring 44; the pre-tightening bolt is detachably connected to the first gasket 42, the second gasket 43 is coupled to the first threaded connection portion 12, and the pre-tightening spring 44 is arranged on the bolt between the first gasket 42 and the second gasket 43.

[0056] In the present embodiment, the first gasket 42 is detachably connected to the pre-tightening bolt in the following manner: a hole is provided on the first gasket 42, the diameter of the hole is larger than the diameter of the threaded portion of the pre-tightening bolt and smaller than the maximum width of the tightening portion of the pre-tightening bolt, and the diameter of the hole on the first gasket 42 is also smaller than the inner diameter of the pre-tightening spring 44, and the width of the first gasket 42 is larger than the outer diameter of the pre-tightening spring 44. A hole is also provided on the second gasket 43, and the second gasket 43 can be coupled and connected with the outer middle surface of the first threaded connection portion 12 through the hole thereon, and the width of the second gasket 43 is larger than the outer diameter of the pre-tightening spring 44. When the anchor rod 31 and the anchor head 33 are fixed in the rock mass 70 through the anchoring resin 80, and the conical surface of the anchor 32 is interference fit with the inner conical surface of the blocking body 20, and the outer surface of the limit portion 11 or the outer surface of the protective tube 60 is inserted into the borehole, in the present embodiment, the outer surface of the limit portion 11 The distance between the outer surface of the surface or protection tube 60 and the inner wall of the borehole is 0.5-0.8 mm. By sleeve-mounting the preload spring on the first threaded connection part 12, and the preload spring 44 is located between the first gasket 42 and the second gasket 43, the preload bolt is threadedly connected to the first threaded connection part 12. By screwing the preload bolt, the first gasket 42 can compress the preload spring 44, and a preload force is applied to the limiting part 11 and the blocking body 20, so that the limiting protrusion 21 abuts against the annular protrusion 13. In this embodiment, as Fig.12As shown, a numerical display column 45 can also be set between the first gasket 42 and the second gasket 43, and a scale value (not shown in the figure) is set on the numerical display column 45. One end of the numerical display column 45 is fixedly connected to the second gasket 43, and the other end passes through the first gasket 42 and is slidably connected to the first gasket 42. When the preload spring 44 is sleeved on the preload bolt and located between the first gasket 42 and the second gasket 43, the numerical display column 45 is located outside the preload spring 44 and is spaced apart from the preload spring 44. In this embodiment, by twisting the preload bolt, the first gasket 42 compresses the preload spring 44, and the scale on the numerical display column 45 can display the distance between the first gasket 42 and the second gasket 43, which is the distance the spring is compressed. In this embodiment, there are two digital display columns, and such a setting can also reduce the relative sliding distance between the first gasket 42 and the second gasket 43. When the elastic coefficient of the preload spring 44 is known, the elastic force of the preload spring 44 can be calculated, which is the preload force between the blocking body 20. The calculation company is as follows: F = KL; wherein F is the elastic force of the preload spring 44, K is the elastic coefficient of the preload spring 44, and L is the distance the preload spring 44 is compressed (degrees on the numerical display column 45), L = (L1 + L2) / 2, wherein L1 is the distance the preload spring 44 is compressed displayed on one digital display column; L2 is the distance the preload spring 44 is compressed displayed on another digital display column. In this embodiment, the magnitude of the pre-tightening force can be adjusted to adapt to the rock mass 70 with different deformation conditions. For the easily deformable rock mass 70, the pre-tightening bolt can be screwed accordingly to make the first gasket 42 compress the spring to a certain extent, appropriately increase the tension of the diameter of the partition body and the limiting part 11, and increase the tension of the anchor rod 31 on the rock mass 70 to the left, so as to offset the tension of the anchor rod 31 to the right when the easily deformable rock mass 70 changes, thereby preventing the rock mass 70 from deforming. Similarly, for the rock mass 70 that is not easy to deform, the pre-tightening force between the limiting part 11 and the blocking body 20 can be appropriately adjusted to avoid excessive pre-tightening force, which leads to excessive tension of the anchor rod 31 and deformation of the rock mass 70. In addition, in this embodiment, it is also possible to indirectly obtain whether the rock mass 70 is deformed by observing the numerical changes on the numerical display column 45 of the first gasket 42 and the second gasket 43, thereby judging whether the variable resistance anchor cable structure and the anchoring are stable.

[0057] This embodiment discloses a method for anchoring a variable resistance anchor cable, comprising the following steps:

[0058] S11: detachably connecting the blocking body 20 and the anchor cable body 30;

[0059] S12: drilling a hole in the rock mass 70, inserting the anchor cable body 30 into the hole, and fixing the anchor cable body 30 in the drill hole with an anchoring resin 80;

[0060] S13: inserting the limiting portion 11 into the borehole, spacing it from the rock mass 70, and leaving the first threaded connection portion 12 outside the borehole;

[0061] S14: threading the pre-tightening assembly 40 to the first threaded connection portion 12 , and making the limiting protrusion 21 abut against the annular protrusion 13 .

[0062] In this embodiment, the inner circumference of the limiting portion 11 gradually decreases from one end of the limiting portion 11 to the other end of the limiting portion 11 along the central axis of the limiting portion 11, and a plurality of annular protrusions 13 with gradually decreasing inner diameters are arranged at intervals on the inner surface of the limiting portion 11, and a limiting protrusion 21 is arranged on the blocking body 20; the limiting protrusion 21 can abut against the annular protrusion 13, and when the force balance of the rock mass 70 is broken and the deformation becomes larger and larger, the tension on the anchor cable body 30 continues to increase, and the blocking body 20 moves the axial direction of the rock limiting portion 11 toward the minimum direction of the inner circumference of the limiting portion 11, and the abutment force between the limiting protrusion 21 and the annular protrusion 13 will also become larger and larger, and the constant resistance is gradually increased to gradually increase the reaction force of the damaged surrounding rock. Under the premise of adapting to the deformation of the surrounding rock of the tunnel, the anchor cable structure will not fail due to constant resistance, and the broken surrounding rock can be better stabilized, so that the broken surrounding rock is tightly clamped to form a stable structure, thereby further preventing the deformation of the rock mass 70.

[0063] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present disclosure.

Claims

1. A variable resistance anchor cable structure, characterized in that: The variable resistance anchor cable structure comprises: A sleeve, a blocking body, an anchor body, and a pre-tightening assembly; the sleeve includes a limiting portion and a first threaded connection portion; the inner circumference of the limiting portion gradually decreases from one end of the limiting portion to the other end of the limiting portion along the central axis of the limiting portion; a plurality of annular protrusions with gradually decreasing inner diameters are arranged at intervals on the inner surface of the limiting portion, and the first threaded connection portion is connected to the end portion at the largest point of the inner circumference of the limiting portion; the pre-tightening assembly is threadedly connected to the first threaded connection portion; the blocking body is arranged in the limiting portion, and a limiting protrusion is arranged on the blocking body; the limiting protrusion can abut against the annular protrusion; the blocking body and the anchor body are detachably connected.

2. A variable resistance anchor cable structure according to claim 1, characterized in that: The outer circumference of the limiting part gradually decreases from one end of the limiting part to the other end of the limiting part along the central axis of the limiting part; the direction in which the inner circumference of the limiting part gradually decreases is the same as the direction in which the outer circumference of the limiting part gradually decreases; a second threaded connection part is provided on the outer circumferential surface of one end of the limiting part, and a third threaded connection part is provided on the outer circumferential surface of the other end; the variable resistance anchor cable structure also includes a protective threaded tube, a bolt is provided on the inner circumferential surface of the protective threaded tube, and the protective threaded tube can be threadedly connected with the second threaded connection part and the third threaded connection part.

3. A variable resistance anchor cable structure according to claim 2, characterized in that: The inner surface of the limiting portion between two adjacent annular protrusions is concave toward the outer peripheral surface of the limiting portion in a radial direction of the limiting portion to form a curved surface.

4. A variable resistance anchor cable structure according to claim 3, characterized in that: The blocking body is in the shape of a cone; the limiting protrusion is arranged in a ring shape along the maximum outer circumference of the blocking body, and a conical hole is provided on the blocking body. The conical hole passes through the blocking body along the central axis of the blocking body, and the maximum end of the conical hole is located at the maximum end face of the blocking body. The blocking body is detachably connected to the anchor body through the conical hole.

5. A variable resistance anchor cable structure according to claim 4, characterized in that: The taper of the tapered hole is equal to the taper of the blocking body.

6. A variable resistance anchor cable structure according to claim 5, characterized in that: The anchor cable body includes an anchor rod, an anchor and an anchor head; one end of the anchor rod is fixedly connected to the anchor head, and the other end is detachably fixedly connected to the anchor, and the length of the anchor rod is greater than the length of the limiting portion; the anchor is conical, and the taper of the anchor is equal to the taper of the conical hole; the conical surface of the anchor can be interference fit with the inner conical surface of the blocking body.

7. A variable resistance anchor cable structure according to claim 6, characterized in that: The anchor head is cylindrical, and its diameter is larger than the diameter of the anchor rod and smaller than the maximum outer diameter of the limiting portion.

8. The variable resistance anchor cable structure according to claim 7, characterized in that: The variable resistance anchor cable structure also includes a baffle plate, on which a fixed connection portion and a limiting through hole are provided. The fixed connection portion can be fixedly connected to the smallest end of the inner circumference of the limiting portion, and the diameter of the limiting through hole is larger than the diameter of the anchor rod.

9. The variable resistance anchor cable structure according to claim 8, characterized in that: The preload assembly includes a preload bolt, a first gasket, a second gasket, and a preload spring; the preload bolt is detachably connected to the first gasket, the second gasket is coupled to the first threaded connection portion, and the preload spring is arranged on the bolt between the first gasket and the second gasket.

10. An anchoring method, the anchoring method being applied to a variable resistance anchor cable structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: S11: detachably connecting the blocking body to the anchor cable body; S12: drilling a hole in the rock mass, inserting the anchor cable body into the hole, and fixing the anchor cable body in the drill hole with an anchoring resin; S13: inserting the limiting part into the borehole, setting it apart from the rock mass, and leaving the first threaded connection part outside the borehole; S14: Threading the pre-tightening assembly to the first threaded connection portion, and allowing the limiting protrusion to abut against the annular protrusion.

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