A tunnelling anchor with adjustable stiffness

Abstract

This invention relates to the field of rock support technology, specifically to a tunnel anchor bolt with adjustable stiffness. It includes an anchor bolt body, a first connector, a deformation adjuster, a pad, a second connector, and a limiting member. The anchor bolt body is fixedly connected to the surrounding rock. A cavity is formed within the anchor bolt body; the first connector is located within the cavity and connected to the anchor bolt body. The deformation adjuster is located within the anchor bolt cavity, with both ends connected to the first and second connectors respectively. One end of the second connector is located within the anchor hole, and the other end passes through the pad and is located outside the anchor hole. The limiting member is located on the side of the pad away from the anchor hole and is connected to the second connector. In the early stages of anchor bolt support, the anchor bolt has relatively low stiffness, allowing the surrounding rock to deform to a certain extent. This deformation allows the surrounding rock to generate a certain self-bearing capacity to maintain its stability, thereby reducing the force on the anchor bolt and preventing damage due to excessive stress, thus ensuring the anchor bolt's support function for the surrounding rock.

Description

Technical Field

[0001] This invention relates to the field of surrounding rock support technology, and more specifically, to a tunnel anchor bolt with adjustable stiffness. Background Technology

[0002] With the improvement of the national economic level, more and more railways are being built or will be planned and constructed. During the railway construction process, tunnels are inevitably excavated. For extra-long tunnels, which have greater burial depth and higher ground stress levels, initial support and secondary lining of the tunnel outline are required during tunnel excavation.

[0003] During the initial support process, anchor bolts are installed on the tunnel profile to prevent deformation of the surrounding rock. Existing anchor bolts, both non-prestressed and prestressed, are of equal stiffness. Because they do not utilize the self-supporting capacity of the surrounding rock, the anchor bolts must withstand significant forces, making them prone to damage and affecting their support function. Summary of the Invention

[0004] The problem addressed by this invention is how to utilize the self-bearing capacity of the surrounding rock to enhance the supporting effect of the anchor bolt on the surrounding rock.

[0005] To solve the above problems, the present invention provides a tunnel anchor bolt with adjustable stiffness, including an anchor bolt body, a first connector, a deformation adjuster, a pad, a second connector, and a limiting member. The anchor bolt body is used to insert into the anchor hole and is fixedly connected to the surrounding rock inside the anchor hole.

[0006] The anchor rod body has a cavity, and the first connector is located in the cavity and connected to the anchor rod body;

[0007] The deformation adjuster is used to be inserted into the anchor hole, and its two ends are respectively connected to the first connector and the second connector. When the deformation adjuster is subjected to a force along the axial direction of the anchor body, it undergoes length deformation along the axial direction of the anchor body.

[0008] The pad is used to be disposed on the outside of the anchor hole. The side of the pad near the anchor hole is used to abut against the tunnel profile surface. One end of the second connector is located inside the anchor hole, and the other end passes through the pad and is located on the outside of the anchor hole. The limiting member is located on the side of the pad away from the anchor hole and is connected to the second connector. The pad is slidably connected to the second connector.

[0009] The technical effects of this invention are as follows: In the early stage of anchor bolt support, with one end of the anchor bolt body fixed inside the surrounding rock within the anchor hole and the pad abutting against the tunnel contour surface, on the one hand, by setting the anchor bolt as a variable stiffness structure, specifically, in the early stage of anchor bolt support, the tension of the first connecting member is relatively small, and the tensile stiffness of the anchor bolt is relatively small, allowing the surrounding rock to deform. The self-bearing capacity generated by the deformation of the surrounding rock is used to maintain its own stability, thereby reducing the force on the anchor bolt and preventing damage due to excessive force, thus ensuring the anchor bolt's support function for the surrounding rock; on the other hand... When the surrounding rock deforms, it pushes the pad plate to move from the inside to the outside. During the movement of the pad plate, it can sequentially drive the limiting component and the second connecting component to move from the inside to the outside. During the movement of the second connecting component from the inside to the outside, it causes the deformation adjuster to deform in length, which can extend the length between the first connecting component and the pad plate, so that the anchor rod is extended as a whole. During this process, the anchor rod body is always fixedly connected to the surrounding rock inside the anchor hole, and the pad plate is always in contact with the tunnel outline, so that the anchor rod can continue to maintain the support function of the surrounding rock and ensure the effectiveness of the anchor rod.

[0010] In the later stages of anchor bolt support, the continued deformation of the surrounding rock pushes the pad plate to move, meaning the force from the inside out increases, which in turn drives the pad plate to move. During the movement of the pad plate, the limiting component and the second connecting component can move from the inside out in sequence. As the second connecting component moves from the inside out, it causes the deformation adjuster to deform in length, which increases the tension on the first connecting component. Thus, when the surrounding rock deforms, it will cause the anchor bolt body to deform from the inside out. The increased tension on the first connecting component, that is, the increased force generated inside the anchor bolt from the outside in, can prevent the anchor bolt body from deforming, thereby enhancing the tensile stiffness of the anchor bolt, improving the anchor bolt's support effect on the surrounding rock, and preventing large deformation of the surrounding rock. This can help avoid tunnel collapse and construction delays.

[0011] Optionally, multiple first connectors are provided, and all of them are disposed within the cavity of the anchor rod body;

[0012] Multiple deformation adjusters are provided, and all of them are located in the anchor holes. The deformation lengths of the multiple deformation adjusters are different, and the multiple first connectors are connected to the multiple deformation adjusters one by one.

[0013] Multiple second connectors are provided, one end of each of the multiple second connectors is connected to one of the multiple deformation adjusters, and the other end of each connector passes through the pad.

[0014] Multiple limiting members are provided, and each of the multiple limiting members is used to connect one-to-one with a multiple of the second connecting members. The distance between the multiple limiting members and the pad is different. The greater the deformation capacity of the deformation adjuster, the smaller the distance between the limiting member and the pad.

[0015] Optionally, the deformation adjuster includes a slip sleeve and a slip damper, the slip damper being interference-fitted with the slip sleeve, the end of the first connecting member being fixedly connected to the slip damper, and the slip sleeve being detachably connected to the second connecting member; the longer the slip sleeve in the deformation adjuster, the greater the deformation capacity.

[0016] Optionally, the anti-slip sleeve is configured as a cylindrical structure with openings at both ends, the anti-slip device is located inside the anti-slip sleeve, and the inner diameter of the anti-slip sleeve gradually decreases from the outside to the inside of the anchor hole; the anti-slip device can be configured as a cylindrical structure, the anti-slip device is coaxially distributed with the anti-slip sleeve, and the outer wall of the anti-slip device abuts against the inner wall of the anti-slip sleeve.

[0017] Optionally, the deformation adjuster further includes a limiting sleeve, which is threadedly connected to one end of the anti-slip sleeve near the anchor body, and the limiting sleeve is used to abut against the anti-slip device.

[0018] Optionally, the deformation adjuster further includes a force transmission sleeve, which is threadedly connected to the end of the anti-slip sleeve away from the anchor body, and the force transmission sleeve is used for threaded connection with the second connecting member.

[0019] Optionally, the anchor body includes a solid rod and a hollow rod, the solid rod and the hollow rod are sequentially arranged in the anchor hole, one end of the solid rod is fixedly connected to the anchor hole, and the other end is fixedly connected to the hollow rod, the cavity is located in the hollow rod.

[0020] Optionally, the second connecting member is configured as a connecting rod, the limiting member is configured as a nut, the side wall of the connecting rod is threaded, and the nut is threadedly connected to the connecting rod.

[0021] Optionally, the stiffness-adjustable tunnel anchor further includes a grouting pipe and a grout-stopping plug. The grout-stopping plug is disposed inside the anchor hole and located between the anchor body and the deformation adjuster. One end of the grouting pipe communicates with the gap between the anchor body and the inner wall of the anchor hole. The other end of the grouting pipe passes through the grout-stopping plug and the pad in sequence and is located outside the anchor hole, and is used to grout the anchor hole.

[0022] Optionally, the rigidity adjustable tunnel anchor also includes an exhaust pipe, one end of which is connected to the gap between the anchor body and the inner wall of the anchor hole, and the other end of which passes through the grout stop plug and the pad in sequence and is located outside the anchor hole, and is used to vent the anchor hole. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the anchor bolt structure according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 Enlarged view of region B in the middle;

[0025] Figure 3 for Figure 1 A sectional view along the A1-A1 direction;

[0026] Figure 4 for Figure 1 A sectional view along the A2-A2 direction;

[0027] Figure 5 This is a schematic diagram of the structure of the first deformation mechanism according to an embodiment of the present invention;

[0028] Figure 6 for Figure 5 A sectional view along the A3-A3 direction;

[0029] Figure 7 for Figure 5 A sectional view along the A4-A4 direction;

[0030] Figure 8 for Figure 5 A sectional view along the A5-A5 direction;

[0031] Figure 9 This is a schematic diagram of the structure of the second deformation mechanism according to an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the third deformation mechanism according to an embodiment of the present invention.

[0033] Figure label:

[0034] 1. Anchor bolt body; 11. Solid bolt body; 12. Hollow bolt body; 3. First connector; 31. First steel strand; 32. Second steel strand; 33. Third steel strand; 4. Deformation adjuster; 41. First deformation mechanism; 411. First anti-slip sleeve; 412. First anti-slip device; 413. First limiting sleeve; 414. First force transmission sleeve; 42. Second deformation mechanism; 421. Second anti-slip sleeve; 422. Second anti-slip device; 423. Second limiting sleeve ; 424, Second force transmission sleeve; 43, Third deformation mechanism; 431, Third anti-slip sleeve; 432, Third anti-slip device; 433, Third limiting sleeve; 434, Third force transmission sleeve; 5, Pad; 6, Limiting component; 61, First nut; 62, Second nut; 63, Third nut; 7, Second connecting component; 71, First connecting rod; 72, Second connecting rod; 73, Third connecting rod; 8, Anchor hole; 91, Grouting pipe; 92, Vent pipe; 93, Grout stop plug. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] In this embodiment, an X-axis coordinate system is established, with the positive X-axis direction representing the outer side and the negative X-axis direction representing the inner side.

[0037] To solve the above problems, such as Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a tunnel anchor bolt with adjustable stiffness, comprising an anchor bolt body 1, a first connector 3, a deformation adjuster 4, a pad 5, a second connector 7, and a limiting member 6. The anchor bolt body 1 is used to insert into the anchor hole 8 and is fixedly connected to the surrounding rock inside the anchor hole 8.

[0038] The anchor bolt body 1 has a cavity inside, and the first connector 3 is located inside the cavity and connected to the anchor bolt body 1.

[0039] The deformation adjuster 4 is used to be inserted into the anchor bolt cavity 12, and its two ends are connected to the first connector 3 and the second connector 7 respectively. When the deformation adjuster 4 is subjected to a force along the axial direction of the anchor bolt body 1, it undergoes length deformation along the axial direction of the anchor bolt body 1.

[0040] The pad 5 is used to be set on the outside of the anchor hole 8. The side of the pad 5 near the anchor hole 8 is used to abut against the tunnel profile surface. One end of the second connector 7 is located inside the anchor hole 8, and the other end passes through the pad 5 and is located on the outside of the anchor hole 8. The limiting member 6 is located on the side of the pad 5 away from the anchor hole 8 and is connected to the second connector 7. The pad 5 is slidably connected to the second connector 7.

[0041] Specifically, the first connecting member 3 can be configured as a steel strand, steel wire rope, or other structures. The deformation adjuster 4 can be configured as an elastic structure, such as a spring, a spring sheet, or other structures; the deformation adjuster 4 can also be configured as a relatively sliding structure, such as a telescopic rod structure, a sliding block, a sliding sleeve structure, etc. The second connecting member 7 can be configured as a connecting rod, a connecting rope, or other structures. The limiting member 6 can be configured as a limiting ring, a nut, etc.

[0042] In this embodiment, anchor holes 8 are first drilled on the tunnel profile surface, and then the anchor body 1 is placed in the anchor holes 8. In the early stage of anchor support, the stiffness of the anchor is relatively small, and its support effect on the surrounding rock is limited. The surrounding rock can deform to a certain extent. When the surrounding rock deforms, the internal forces change, generating a certain self-bearing capacity on the periphery of the tunnel profile surface. This can maintain the stability of the surrounding rock itself to a certain extent and reduce the force exerted by the surrounding rock on the anchor.

[0043] In summary, during the early stage of anchor bolt support, with one end of the anchor bolt body 1 fixed inside the surrounding rock within the anchor hole and the pad 5 abutting against the tunnel contour surface, on the one hand, by setting the anchor bolt as a variable stiffness structure—specifically, in the early stage of anchor bolt support, the tension of the first connecting piece 3 is relatively small, and the tensile stiffness of the anchor bolt is relatively small—allowing the surrounding rock to deform. The self-bearing capacity generated by the deformation of the surrounding rock maintains its own stability, thereby reducing the force on the anchor bolt and preventing damage due to excessive force, thus ensuring the anchor bolt's support function for the surrounding rock. On the other hand, when the surrounding rock deforms... The pad 5 is pushed to move from the inside to the outside. During the movement of the pad 5, the limiting piece 6 and the second connecting piece 7 can be driven to move from the inside to the outside in sequence. During the movement of the second connecting piece 7 from the inside to the outside, the deformation adjuster 4 is deformed, which can extend the length between the first connecting piece 3 and the pad 5, so that the anchor rod is extended as a whole. During this process, the anchor rod body 1 is always fixedly connected to the surrounding rock inside the anchor hole 8, and the pad 5 is always in contact with the tunnel outline surface, so that the anchor rod can continue to maintain the support function of the surrounding rock and ensure the effect of the anchor rod.

[0044] In the later stages of anchor bolt support, the surrounding rock continues to deform, meaning the force from the inside out increases, which pushes the pad 5 to move. During the movement of the pad 5, the limiting member 6 and the second connecting member 7 can move from the inside out in sequence. During the movement of the second connecting member 7 from the inside out, the deformation adjuster 4 undergoes length deformation, which increases the tension on the first connecting member 3. Thus, when the surrounding rock deforms, it will cause the anchor bolt body 1 to deform from the inside out. The increased tension of the first connecting member 3, that is, the increased force generated inside the anchor bolt from the outside in, can prevent the anchor bolt body 1 from deforming, thereby enhancing the tensile stiffness of the anchor bolt, improving the anchor bolt's support effect on the surrounding rock, and preventing large deformation of the surrounding rock. This can help avoid tunnel collapse and construction delays.

[0045] Optionally, multiple first connectors 3 are provided, and all of them are located in the cavity of the anchor body 1;

[0046] Multiple deformation adjusters 4 are provided, and all of them are set in the anchor hole 8. The deformation lengths of the multiple deformation adjusters 4 are different, and the multiple first connecting pieces 3 are connected to the multiple deformation adjusters 4 one by one.

[0047] Multiple second connectors 7 are provided. One end of each of the multiple second connectors 7 is connected to a corresponding multiple deformation adjusters 4, and the other end of each connector passes through the pad 5.

[0048] Multiple limiting components 6 are provided, and each limiting component 6 is used to connect one-to-one with multiple second connecting components 7. The distance between the multiple limiting components 6 and the pad 5 is different. The greater the deformation capacity of the deformation adjuster 4, the smaller the distance between the limiting component 6 and the pad 5.

[0049] Specifically, such as Figures 1-6 as well as Figure 9 , Figure 10 As shown, multiple first connecting parts 3 are provided, which can be first steel strand 31, second steel strand 32, and third steel strand 33 respectively; correspondingly, multiple deformation adjusters 4 are provided, which can be first deformation mechanism 41, second deformation mechanism 42, and third deformation mechanism 43 respectively; multiple second connecting parts 7 are provided, which can be first connecting rod 71, second connecting rod 72, and third connecting rod 73 respectively; multiple limiting parts 6 are provided, which can be first nut 61, second nut 62, and third nut 63 respectively, wherein the distance between the first nut 61, second nut 62, and third nut 63 and the pad 5 increases sequentially.

[0050] In this embodiment, during the later stage of anchor bolt support, since the pad 5 directly abuts against the tunnel contour surface, the surrounding rock continues to deform, that is, the force of the surrounding rock from the inside to the outside increases, which will push the pad 5 to move from the inside to the outside. The pad 5 pushes the first nut 61 to move from the inside to the outside, and then drives the first connecting rod 71 to move from the inside to the outside, and causes the first deformation mechanism 41 to undergo length deformation. When the first deformation mechanism 41 deforms, it will increase the force generated by the first steel strand 31 inside the anchor bolt body 1 from the outside to the inside to the first tensile force, thereby raising the anchor bolt to the first level of stiffness. Subsequently, if the surrounding rock continues to deform, it will push the pad 5 to continue moving from the inside to the outside. The pad 5 will simultaneously push the first nut 61 and the second nut 62 to move from the inside to the outside, and then drive the first connecting rod 71 and the second connecting rod 72 to move from the inside to the outside, and drive the second deformation mechanism 42 to undergo length deformation. The first deformation mechanism 41 continues to undergo length deformation. When both the first deformation mechanism 41 and the second deformation mechanism 42 are deformed, the first steel strand 31 and the second steel strand 32 will be tightened at the same time, and the force generated by the first steel strand 31 and the second steel strand 32 inside the anchor body 1 from the outside to the inside will be increased to the second tensile force, thereby increasing the anchor to the second-level stiffness. Subsequently, if the surrounding rock continues to deform, it will push the pad 5 to continue moving from the inside out. The pad 5 will simultaneously push the first nut 61, the second nut 62, and the third nut 63 to move from the inside out, and then sequentially drive the first connecting rod 71, the second connecting rod 72, and the third connecting rod 73 to move from the inside out, and drive the third deformation mechanism 43 to undergo length deformation. The first deformation mechanism 41 and the second deformation mechanism 42 will continue to undergo length deformation. When the first deformation mechanism 41, the second deformation mechanism 42, and the third deformation mechanism 43 all deform, they will simultaneously tighten the first steel strand 31, the second steel strand 32, and the third steel strand 33, and increase the force generated by the first steel strand 31, the second steel strand 32, and the third steel strand 33 inside the anchor body 1 from the outside in to the third tensile force, thereby raising the anchor to the third level of stiffness. Therefore, by setting multiple first connectors 3, deformation adjusters 4, second connectors 7, and limiting members 6, and setting multiple deformation adjusters 4 to have different deformation capabilities, and setting multiple limiting members 6 to have different distances from the pad 5, the tensile force of multiple first connectors 3 can be gradually increased during the deformation of the surrounding rock, thereby increasing the stiffness of the anchor bolt step by step, improving the support effect of the anchor bolt, and thus preventing large deformation of the surrounding rock.

[0051] Optionally, the deformation adjuster 4 includes a slip sleeve and a slip device, the slip device and the slip sleeve are interference-fitted, the end of the first connecting member 3 is fixedly connected to the slip device, and the slip sleeve and the second connecting member 7 are detachably connected; the longer the slip sleeve in the deformation adjuster 4 is, the stronger the deformation capacity.

[0052] Specifically, such as Figures 5-10As shown, the first deformation mechanism 41 includes a first anti-slip sleeve 411 and a first anti-slip device 412; the second deformation mechanism 42 includes a second anti-slip sleeve 421 and a second anti-slip device 422; and the third deformation mechanism 43 includes a third anti-slip sleeve 431 and a third anti-slip device 432.

[0053] In this embodiment, during the later stages of anchor bolt support, as the pad 5 directly contacts the tunnel contour surface and the surrounding rock continues to deform, it will push the pad 5 to move from the inside out. The pad 5 will push the first nut 61 to move from the inside out, and then drive the first connecting rod 71 to move from the inside out. This can drive the first anti-slip sleeve 411 to move from the inside out. Since the first anti-slip device 412 and the first anti-slip sleeve 411 are interference-fitted, the first steel strand 31 can be tightened, and the force generated by the first steel strand 31 inside the anchor bolt body 1 from the outside to the inside can be increased to the first tensile force, thereby increasing the anchor bolt to the first level of stiffness. Subsequently, as the surrounding rock continues to deform, it will push the pad 5 to move from the inside to the outside. The pad 5 will push the second nut 62 to move from the inside to the outside, and then drive the second connecting rod 72 to move from the inside to the outside. This can drive the second anti-slip sleeve 421 to move from the inside to the outside. Since the second anti-slip device 422 and the second anti-slip sleeve 421 are interference-fitted, the second steel strand 32 can be tightened, and the force generated by the first steel strand 31 and the second steel strand 32 inside the anchor body 1 from the outside to the inside will be increased to the second tensile force, thereby increasing the anchor to the second-level stiffness. Subsequently, as the surrounding rock continues to deform, it pushes the pad 5 to move from the inside out. The pad 5 then pushes the third nut 63 to move from the inside out, which in turn drives the third connecting rod 73 to move from the inside out. This, in turn, drives the third anti-slip sleeve 431 to move from the inside out. Because the third anti-slip device 432 and the third anti-slip sleeve 431 are interference-fitted, the third steel strand 33 can be tightened, and the outward-to-inward force generated by the first steel strand 31, the second steel strand 32, and the third steel strand 33 inside the anchor bolt body 1 can be increased to the third tensile force, thereby increasing the anchor bolt to the third stiffness level. Thus, the deformation adjuster 4 includes an anti-slip sleeve and an anti-slip device. The anti-slip sleeve and the anti-slip device are interference-fitted. When the tensile force on the anti-slip sleeve is greater than the frictional force between the anti-slip sleeve and the anti-slip device, the anti-slip sleeve and the anti-slip device can be driven to move relative to each other. Meanwhile, when multiple deformation adjusters 4 are set, during the continuous deformation of the surrounding rock, when the first anti-slip device 412 moves from the outside to the inside to the end of the first anti-slip sleeve 411, when the second anti-slip device 422 moves from the outside to the inside to the end of the second anti-slip sleeve 421, when the third anti-slip device 432 moves from the outside to the inside to the end of the third anti-slip sleeve 431 towards the anchor hole 8.

[0054] Optionally, the anti-slip sleeve is configured as a cylindrical structure with open ends, and the anti-slip device is located inside the anti-slip sleeve. The inner diameter of the anti-slip sleeve gradually decreases from the outside to the inside of the anchor hole 8. The anti-slip device can be configured as a cylindrical structure, with the anti-slip device and the anti-slip sleeve coaxially distributed, and the outer wall of the anti-slip device abutting against the inner wall of the anti-slip sleeve.

[0055] In this embodiment, during the later stages of anchor bolt support, as the pad 5 directly abuts against the tunnel contour surface and the surrounding rock continues to deform, it pushes the pad 5 to move from the inside out. The pad 5 pushes the first nut 61 to move from the inside out, which in turn drives the second connecting member 7 to move from the inside out. This, in turn, drives the anti-slip sleeve to move from the inside out. Since the inner diameter of the anti-slip device gradually decreases from the outside to the inside of the anchor hole 8, the tension required by the anti-slip sleeve during the relative movement of the anti-slip sleeve and the anti-slip device increases. Consequently, the tension transmitted to the first connecting member 3 increases, and the outward-to-inward force generated by the first connecting member 3 inside the anchor bolt body 1 also continuously increases, thereby continuously improving the stiffness of the anchor bolt. Thus, by setting an anti-slip sleeve with a gradually decreasing inner diameter and setting an anti-slip device coaxial with the anti-slip sleeve and abutting against the inner wall of the anti-slip sleeve, the tension inside the anchor bolt body 1 continuously increases, thereby continuously improving the stiffness of the anchor bolt, enhancing the support effect of the anchor bolt, and preventing large deformation of the surrounding rock.

[0056] Optionally, the deformation adjuster 4 also includes a limiting sleeve, which is threadedly connected to one end of the anti-slip sleeve near the anchor body 1, and the limiting sleeve is used to abut against the anti-slip device.

[0057] Specifically, such as Figures 5-10 As shown, the first deformation mechanism 41 includes a first limiting sleeve 413, the second deformation mechanism 42 includes a second limiting sleeve 423, and the third deformation mechanism 43 includes a third limiting sleeve 433. Simultaneously, small holes are provided at the ends of the first limiting sleeve 413, the second limiting sleeve 423, and the third limiting sleeve 433 near the anchor bolt body 1, to allow the first steel strand 31, the second steel strand 32, and the third steel strand 33 to pass through, respectively.

[0058] In this embodiment, during the later stages of anchor bolt support, as the pad 5 directly abuts against the tunnel contour surface, the surrounding rock continues to deform. During the relative movement of the anti-slip sleeve and the anti-slip device, the tension required by the anti-slip sleeve increases, which in turn increases the tension transmitted to the first connecting member 3. The outward-to-inward force generated by the first connecting member 3 inside the anchor bolt body 1 also continuously increases, thereby continuously improving the rigidity of the anchor bolt. At the same time, a limiting sleeve is threadedly connected to the end of the anti-slip sleeve near the anchor bolt body 1. When the anti-slip device moves to abut against the limiting sleeve, it can limit the anti-slip device and prevent it from detaching from the anti-slip sleeve, thus ensuring the effectiveness of the deformation adjuster 4.

[0059] Optionally, the deformation adjuster 4 also includes a force transmission sleeve, which is threadedly connected to the end of the anti-slip sleeve away from the anchor body 1, and the force transmission sleeve is used to be threadedly connected to the second connecting member 7.

[0060] Specifically, such as Figures 5-10 As shown, the first deformation mechanism 41 includes a first force transmission sleeve 414, the second deformation mechanism 42 includes a second force transmission sleeve 424, and the third deformation mechanism 43 includes a third force transmission sleeve 434.

[0061] In this embodiment, when the surrounding rock deforms, the pad 5 moves from the inside to the outside, driving the second connecting member 7 to move from the inside to the outside. Since the force transmission sleeve is threadedly connected to the second connecting member 7, the force transmission sleeve moves from the inside to the outside. Since the force transmission sleeve is threadedly connected to the end of the anti-slip sleeve away from the anchor body 1, the anti-slip sleeve can be driven to move from the inside to the outside. Thus, the transmission effect between the pad 5 and the anti-slip sleeve is guaranteed.

[0062] Alternatively, the force transmission sleeve can also be welded to the second connector 7.

[0063] Specifically, the first force transmission sleeve 414 is welded to the first connecting rod 71, the second force transmission sleeve 424 is welded to the second connecting rod 72, and the third force transmission sleeve 434 is welded to the third connecting rod 73.

[0064] Optionally, each of the first connector 3, deformation adjuster 4, second connector 7, and limiting member 6 is provided in twos, and the two first connectors 3, deformation adjusters 4, second connectors 7, and limiting members 6 are arranged opposite to each other.

[0065] In this embodiment, each component is provided with two deformation adjusters 4, a first connector 3, a second connector 7, and a limiting member 6. The two deformation adjusters 4, the first connector 3, the second connector 7, and the limiting member 6 are arranged opposite to each other, so that the stiffness on both sides of the anchor rod can be strengthened at the same time, ensuring the uniformity of the force on the anchor rod.

[0066] Optionally, such as Figure 1 As shown, the anchor body 1 includes a solid rod 11 and a hollow rod 12. The solid rod 11 and the hollow rod 12 are sequentially arranged in the anchor hole 8. One end of the solid rod 11 is fixedly connected to the anchor hole 8, and the other end is fixedly connected to the hollow rod 12. The cavity is located inside the hollow rod 12.

[0067] In this embodiment, the end of the anchor body 1 closest to the inside of the anchor hole 8 needs to be fixedly connected to the surrounding rock. That is, the internal force of the anchor body 1 is relatively large. Therefore, the anchor body 1 is set as a solid rod 11 and a hollow rod 12, and the solid rod 11 is fixedly connected to the surrounding rock. Then, the force of the surrounding rock on the anchor body 1 is mainly concentrated on the solid rod 11. The solid rod 11 has stronger rigidity than the hollow rod 12, which is beneficial to prevent the anchor from being damaged, thereby enhancing the support effect of the anchor.

[0068] Optionally, the first connector 3 is configured as a steel strand, with one end of the steel strand connected to the solid rod 11 and the other end connected to the anti-slip device.

[0069] In this embodiment, the first connector 3 is configured as a steel strand, with one end of the steel strand connected to the solid rod 11 and the other end connected to the anti-slip device. When multiple first connectors 3 are provided, the lengths of the steel strands in the multiple first connectors 3 are different; each first connector 3 includes at least two steel strands, and the multiple steel strands are arranged in pairs.

[0070] Optionally, the second connecting member 7 is configured as a connecting rod, the limiting member 6 is configured as a nut, the side wall of the connecting rod is threaded, and the nut is threadedly connected to the connecting rod.

[0071] Specifically, the end of the connecting rod near the inside of the anchor hole 8 is threaded or welded to the force transmission sleeve.

[0072] In this embodiment, the pad 5 has an assembly hole relative to the connecting rod. After the connecting member passes through the assembly hole on the pad 5, it is threadedly connected to the connecting rod with a nut, and the distance between the nut and the pad 5 is adjusted. Thus, by setting the second connecting member 7 as the connecting rod, and threading it on the side wall of the connecting rod, and setting the limiting member 6 as the nut, the position of the nut on the connecting rod can be adjusted relatively easily, thereby facilitating the adjustment of the distance between the nut and the pad 5.

[0073] Optionally, such as Figure 1 As shown, the tunnel anchor bolt with adjustable stiffness also includes a grouting pipe 91 and a grout stopper 93. The grout stopper 93 is installed inside the anchor hole 8 and located between the anchor bolt body 1 and the deformation adjuster 4. One end of the grouting pipe 91 is connected to the gap between the anchor bolt body 1 and the inner wall of the anchor hole 8. The other end of the grouting pipe 91 passes through the grout stopper 93 and the pad 5 in sequence and is located outside the anchor hole 8, and is used to grout the anchor hole 8.

[0074] In this embodiment, the outer wall of the anchor bolt body 1, the anchor hole 8, and the grout stop plug 93 together form a cavity. A grouting pipe 91 connects to this cavity, and cement grout or cement mortar or other grouting materials are injected into the sealed space through the grouting pipe 91 to fill the gap between the anchor bolt body 1 and the surrounding rock, thereby enhancing the anchor bolt's support effect on the surrounding rock. Simultaneously, the grout stop plug 93 prevents leakage of the grouting material within the sealed space.

[0075] Optionally, such as Figure 1 As shown, the tunnel anchor bolt with adjustable stiffness also includes an exhaust pipe 92. One end of the exhaust pipe 92 is connected to the gap between the anchor bolt body 1 and the inner wall of the anchor hole 8. The other end of the exhaust pipe 92 passes through the grout stop plug 93 and the pad 5 in sequence and is located outside the anchor hole 8, and is used to vent the anchor hole 8.

[0076] In this embodiment, during the grouting process, the air in the anchor hole 8 is discharged using the vent pipe 92, which can prevent air bubbles from appearing in the grouting material and causing the grouting to be incomplete. This helps to ensure the stability of the connection between the anchor body 1 and the surrounding rock, thereby enhancing the support effect of the anchor on the surrounding rock.

[0077] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A tunnel anchor bolt with adjustable stiffness, characterized in that, Includes an anchor body (1), a first connector (3), a deformation adjuster (4), a pad (5), a second connector (7), and a limiting member (6). The anchor body (1) is used to insert into the anchor hole (8) and is fixedly connected to the surrounding rock inside the anchor hole (8). The anchor body (1) has a cavity, and the first connector (3) is located in the cavity and connected to the anchor body (1). The deformation adjuster (4) is used to be inserted into the anchor hole (8), and its two ends are respectively connected to the first connector (3) and the second connector (7). When the deformation adjuster (4) is subjected to a force along the axial direction of the anchor body (1), it undergoes length deformation along the axial direction of the anchor body (1). The pad (5) is used to be disposed on the outside of the anchor hole (8). The side of the pad (5) near the anchor hole (8) is used to abut against the tunnel profile surface. One end of the second connector (7) is located inside the anchor hole (8), and the other end passes through the pad (5) and is located on the outside of the anchor hole (8). The limiting member (6) is located on the side of the pad (5) away from the anchor hole (8) and is connected to the second connector (7). The first connector (3) is provided in multiple forms, and all of them are provided in the cavity of the anchor body (1); Multiple deformation adjusters (4) are provided, and the deformation lengths of the multiple deformation adjusters (4) are different. Multiple first connectors (3) are connected to the multiple deformation adjusters (4) in a one-to-one correspondence. Multiple second connectors (7) are provided, one end of each of the multiple second connectors (7) is connected to one of the multiple deformation adjusters (4), and the other end of each connector passes through the pad (5); Each of the limiting members (6) is provided in multiples, and each of the multiple limiting members (6) is used to connect one-to-one with each of the multiple second connecting members (7). The distance between the multiple limiting members (6) and the pad (5) is different. The greater the deformation capacity of the deformation adjuster (4), the smaller the distance between the limiting member (6) and the pad (5).

2. The tunnel anchor bolt with adjustable stiffness as described in claim 1, characterized in that, The deformation adjuster (4) includes a slip sleeve and a slip device. The slip device is interference-connected to the slip sleeve. The end of the first connecting member (3) is fixedly connected to the slip device. The slip sleeve is detachably connected to the second connecting member (7). The longer the slip sleeve in the deformation adjuster (4) is, the stronger the deformation capacity.

3. The tunnel anchor bolt with adjustable stiffness as described in claim 2, characterized in that, The anti-slip sleeve is configured as a cylindrical structure with open ends. The anti-slip device is located inside the anti-slip sleeve. The inner diameter of the anti-slip sleeve gradually decreases from the outside to the inside of the anchor hole (8). The anti-slip device is configured as a cylindrical structure. The anti-slip device is coaxially distributed with the anti-slip sleeve, and the outer wall of the anti-slip device abuts against the inner wall of the anti-slip sleeve.

4. The tunnel anchor bolt with adjustable stiffness as described in claim 3, characterized in that, The deformation adjuster (4) also includes a limiting sleeve, which is threadedly connected to one end of the anti-slip sleeve near the anchor body (1), and the limiting sleeve is used to abut against the anti-slip device.

5. The tunnel anchor bolt with adjustable stiffness as described in claim 4, characterized in that, The deformation adjuster (4) also includes a force transmission sleeve, which is threadedly connected to the end of the anti-slip sleeve away from the anchor body (1), and the force transmission sleeve is used to be threadedly connected to the second connecting member (7).

6. The tunnel anchor bolt with adjustable stiffness as described in claim 1, characterized in that, The anchor body (1) includes a solid rod body (11) and a hollow rod body (12). The solid rod body (11) and the hollow rod body (12) are sequentially arranged in the anchor hole (8). One end of the solid rod body (11) is fixedly connected to the anchor hole (8), and the other end is fixedly connected to the hollow rod body (12). The cavity is located inside the hollow rod body (12).

7. The tunnel anchor bolt with adjustable stiffness as described in claim 6, characterized in that, The second connecting member (7) is configured as a connecting rod, the limiting member (6) is configured as a nut, the side wall of the connecting rod is threaded, and the nut is threadedly connected to the connecting rod.

8. The tunnel anchor bolt with adjustable stiffness as described in claim 1, characterized in that, It also includes a grouting pipe (91) and a grout stopper (93). The grout stopper (93) is disposed in the anchor hole (8) and located between the anchor rod body (1) and the deformation adjuster (4). One end of the grouting pipe (91) communicates with the gap between the anchor rod body (1) and the inner wall of the anchor hole (8). The other end of the grouting pipe (91) passes through the grout stopper (93) and the pad (5) in sequence and is located outside the anchor hole (8), and is used to grout the anchor hole (8).

9. The tunnel anchor bolt with adjustable stiffness as described in claim 8, characterized in that, It also includes an exhaust pipe (92), one end of which is connected to the gap between the anchor body (1) and the inner wall of the anchor hole (8), and the other end of which passes through the grout stop plug (93) and the pad (5) in sequence, and is located outside the anchor hole (8), and is used to exhaust the anchor hole (8).

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