Flexible cutting rod, anchor rod and tunnel anchor rod construction method

Abstract

The invention discloses a flexible cutting rod, an anchor rod and a tunnel anchor rod construction method, the flexible cutting rod comprises a driving rod, a transmission rod and a cutting saw blade, the driving rod is connected with the transmission rod through a spring, one end of the transmission rod is connected with the cutting saw blade, and through driving input, a whole formed by connecting the driving rod, the spring, the transmission rod and the cutting saw blade rotates in the circumferential direction; drilling and digging an anchor rod mounting hole, and mounting an anchor rod with a cutting opening and a plurality of fixing tongue openings in the end part in the hole; vertical spaces corresponding to the fixed tongue openings are cut in the wall face of the hole through a cutting saw blade of a flexible cutting rod, the multiple fixed tongue openings correspond to the multiple vertical spaces one to one, and then the fixed tongues are pushed into the vertical spaces through the fixed tongue openings; and the fixing tongue is fixed in the vertical space, grouting is conducted on the hole, the anchor rod is tightly connected with the hole, and finally the hole is blocked. The anchor rod can be applied to different stratum structures, the anchoring force of the anchor rod is increased, and anchor rod construction is faster and more efficient.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel anchor bolt fixing construction, and in particular to a flexible cutting rod, an anchor bolt and a tunnel anchor bolt construction method. Background Art

[0002] In tunnel engineering, anchors play an important role, not only enhancing geological stability and the stability of the supporting structure, but also reducing surface deformation, providing construction support, and extending the service life of the tunnel. However, the existing tunnel anchor construction method and the anchoring force of the anchor structure are affected by geological conditions, and specific geological conditions may result in insufficient anchoring force generated by the anchor.

[0003] For example, 1. When the tunnel passes through a soft soil layer, the shear strength and bearing capacity of these soils are low. The anchor rod may not be able to obtain sufficient friction resistance or support in the soft soil layer, resulting in insufficient anchoring force. 2. When there are rock joints, these joints are cracks or fissures. If the direction of these joints is perpendicular or nearly perpendicular to the direction of the anchor rod, it may lead to insufficient anchoring force. In this case, the anchor rod cannot effectively obtain the support force of the rock. 3. When the tunnel passes through a fault zone, the movement on the fault plane will affect the stability and anchoring effect of the rock. The anchor rod near the fault zone may have insufficient anchoring force due to the instability of the rock. 4. When the tunnel passes through a saturated layer underground, the penetration of water will weaken the shear strength of the soil or rock, thereby reducing the anchoring force of the anchor rod. Or when a sandy soil layer containing a large amount of fine particles may be lost when the anchor rod is anchored, resulting in a weakened anchoring force.

[0004] Under these geological conditions, the anchoring force of the anchor rod may be affected. These factors need to be specially considered during engineering design and construction, and corresponding measures need to be taken to increase the anchoring force and ensure the safety and stability of the tunnel project.

[0005] When the anchoring force of existing tunnel bolt construction is insufficient, the friction resistance and supporting force in the stratum can be improved by increasing the length of the bolt. By using longer bolts, it can be ensured that they are anchored in deeper stable strata. Increasing the number and density of bolts can improve the overall anchoring effect. However, both have requirements on the strength of the bolt material, geological environment, and construction environment, and are not suitable for all engineering conditions.

[0006] Furthermore, if the geological conditions are particularly bad, the ground may be reinforced, such as by grouting, rock anchor spraying, etc., to improve the stability and anchoring force of the ground. However, this method greatly increases the construction operations and easily leads to an increase in construction costs.

[0007] Therefore, in the existing tunnel anchor construction process, there are problems such as lack of ability to cope with various soil structures and lack of anchor force caused by the existing anchor construction method, as well as increased complexity of construction operations and increased construction costs caused by other anchor fixing methods. Summary of the invention

[0008] The object of the present invention is to provide a tunnel anchor rod and a construction method thereof, so as to solve the technical problem in the prior art that the existing tunnel anchor rod cannot cope with various soil layer structures during construction, resulting in a lack of anchoring force.

[0009] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A flexible cutting rod, comprising a driving rod, a transmission rod and a cutting saw blade, wherein one end of the driving rod forms a driving input end, the other end of the driving rod is connected to the transmission rod through a spring, the end of the transmission rod away from the elastic member is connected to the cutting saw blade, and the driving rod and the transmission rod share a common axis when not subject to external forces; the transmission rod is eccentrically connected to the cutting saw blade; Wherein, under the action of the torque input to the driving input end, the entirety of the driving rod, the spring, the transmission rod and the cutting saw blade rotates circumferentially, thereby realizing the cutting action of the cutting saw blade.

[0010] As a preferred solution of the present invention, under the action of the torque input to the drive input end, the spring allows: The driving rod and the transmission rod revolve away from the axis, and the cutting saw blade rotates around its geometric center; Or, the driving rod and the transmission rod revolve away from the axis, and the cutting saw blade revolves away from its geometric center; Alternatively, the driving rod and the transmission rod rotate circumferentially around the axis, and the cutting saw blade revolves away from its geometric center.

[0011] As a preferred solution of the present invention, it also includes a stiffness control device, the stiffness control device includes a transmission shaft, one end of the transmission shaft is provided with a driving part, the other end of the transmission shaft is movably connected with a connecting shaft, and the end of the connecting shaft away from the transmission shaft is movably connected to the end center position of the transmission rod; Part of the transmission shaft is arranged inside the driving rod along the axial direction of the driving rod, the driving part is arranged inside the driving rod, the driving part is used to drive the transmission shaft to move along the axial direction of the driving rod, and the connecting shaft pulls the driving rod closer to or away from the driving rod, so that the spring is compressed or extended.

[0012] As a preferred solution of the present invention, the driving part includes a cavity arranged in the driving rod, a sealing piston member is arranged in the cavity, the sealing piston member divides the cavity into a balancing cavity and a hydraulic cavity, one end of the transmission shaft passes through the hydraulic cavity and is connected to the center of one end surface of the sealing piston member, the driving rod corresponding to the hydraulic cavity is provided with an adjusting cavity, a sealing screw is arranged in the adjusting cavity, the sealing screw is threadedly connected to the inner wall of the adjusting cavity, and the adjusting cavity is connected to the hydraulic cavity; The sealing screw is rotated to compress the liquid in the hydraulic chamber, thereby driving the sealing piston to move along the axial direction of the chamber.

[0013] The present invention provides a tunnel anchor construction method, using the flexible cutting rod, comprising the following steps: Step 100, drilling an anchor installation hole on the tunnel wall according to the anchor design requirements, and installing an anchor with a cutting opening at the end and a plurality of fixing tongue openings evenly distributed on the circumferential surface in the hole; Step 200, using the cutting saw blade of the flexible cutting rod to be sent to a position corresponding to the cutting opening of the anchor rod, cutting the hole wall outside the anchor rod through the cutting opening to cut out a vertical space; The position of the cutting opening is adjusted by rotating the anchor rod so that the cutting saw blade cuts a plurality of vertical spaces on the circumferential surface of the hole, the same number as the plurality of fixing tongue openings; Step 300, adjusting the relative position of the anchor rod along the axial direction of the hole so that the plurality of fixing tongue openings correspond to the plurality of vertical spaces one by one, and then pushing the fixing tongues into the vertical spaces through the fixing tongue openings; Step 400, grouting is performed on the hole to fix the fixing tongue in the vertical space, and the anchor rod is tightly connected to the hole, and finally the hole is sealed.

[0014] As a preferred solution of the present invention, after the cutting saw blade using the flexible cutting rod is sent to a position corresponding to the cutting opening of the anchor rod, under the torque input at the driving input end: The flexible cutting rod is limited by the inner diameter of the anchor rod, so that the driving rod and the transmission rod revolve away from the axis, and the cutting saw blade rotates around its geometric center without cutting the hole wall through the cutting opening; When the driving rod and the transmission rod revolve away from the axis, the cutting saw blade revolves away from its geometric center, the revolving radius of the cutting saw blade is greater than the outer diameter of the anchor rod, and the cutting saw blade starts to cut the wall of the hole through the cutting opening; When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting saw blade performs a revolution movement deviating from its geometric center, and in this state, the vertical space cutting of the hole wall is completed.

[0015] As a preferred solution of the present invention, according to the formation characteristics of the inner wall of the hole, the length of the spring is stretched or compressed by a stiffness control device to adjust the stiffness of the flexible cutting rod.

[0016] As a preferred solution of the present invention, after the anchor bolt installation holes are drilled on the tunnel wall according to the anchor bolt design requirements, concrete or polymer slurry is injected into the holes to fix the hole walls.

[0017] The present invention provides an anchor rod, which is applied to the tunnel anchor rod construction method. The anchor rod includes a hollow rod body, one end of the hollow rod body is closed, and the other end is open to form an opening. The cutting opening is arranged on the rod body surface close to the closed end of the hollow rod body. The cutting opening is along the circumferential direction of the hollow rod body. A plurality of the fixing tongue openings are evenly distributed on the rod body of the hollow rod body between the cutting opening and the closed end of the hollow rod body.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The end structure of the anchor rod provided by the present invention after construction is completed not only exerts the friction force of the rod body, but also fully exerts the end bearing force through the fixed tongue structure, thereby greatly improving the anchoring effect of the anchor rod under unfavorable geological conditions.

[0019] (2) The anchor rod provided by the present invention can achieve different working states of the cutting saw blade by adjusting the spring structure, thereby cutting the wall surface of the tunnel hole, which is suitable for various stratum structure characteristics of the tunnel and achieves more efficient cutting.

[0020] (3) The anchor rod and the flexible cutting rod used in the construction provided by the present invention have a simple overall structure and are convenient for large-scale use in engineering projects.

[0021] (4) The present invention provides a method for constructing tunnel anchor bolts. The overall construction process is simple and on-site construction can be quickly started, which speeds up the project progress and improves construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0023] Figure 1 is a schematic diagram of the longitudinal cross-sectional structure of the anchor rod relative to the tunnel wall according to an embodiment of the present invention; Figure 2A schematic diagram of the anchor rod structure according to an embodiment of the present invention; Figure 3 It is a schematic structural diagram of a flexible cutting rod according to an embodiment of the present invention; Figure 4 It is a schematic diagram of a flexible cutting rod in a first stage state according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the rotation state of the cutting saw blade when the flexible cutting rod according to the embodiment of the present invention is in the second stage state; Figure 6 is a schematic diagram of a flexible cutting rod in a second stage state according to an embodiment of the present invention; Figure 7 It is a schematic diagram of the rotation state of the cutting saw blade when the flexible cutting rod according to the embodiment of the present invention is in the second stage state; Figure 8 is a schematic diagram of a flexible cutting rod in a third stage state according to an embodiment of the present invention; Fig. 9 It is a schematic diagram of the rotation state of the cutting saw blade when the flexible cutting rod according to the embodiment of the present invention is in the third stage state; Fig.10 A schematic diagram of a flexible cutting rod spring adjustment structure according to an embodiment of the present invention; Fig.11 A schematic diagram of a tunnel anchor construction method according to an embodiment of the present invention; Fig.12 It is a structural schematic diagram of a stiffness control device for a flexible cutting rod according to an embodiment of the present invention; Fig.13 Schematic diagram of the driving structure of an embodiment of the present invention.

[0024] The numbers in the figure represent the following: 1-hollow rod body; 2-cutting mouth; 3-fixing tongue mouth; 4-tunnel surrounding rock where the hole is located; 5-hole; 6-fixing tongue; 7-cutting saw blade; 8-spring; 9-driving rod; 10-transmission rod; 11-stiffness control device; 111-transmission shaft; 112-driving part; 113-connecting shaft; 114-chamber; 115-sealing piston; 116-balancing chamber; 117-hydraulic chamber; 118-adjusting chamber; 119-sealing screw. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figures 1 to 11 As shown, the present invention provides a flexible cutting rod, including a driving rod 9, a transmission rod 10 and a cutting saw blade 7, one end of the driving rod 9 forms a driving input end, the other end of the driving rod 9 is connected to the transmission rod 10 through a spring 8, the end of the transmission rod 10 away from the elastic member is connected to the cutting saw blade 7, and the driving rod 9 and the transmission rod 10 share a common axis when not affected by external forces; the transmission rod 10 is eccentrically connected to the cutting saw blade 7.

[0027] Among them, under the action of the torque input to the driving input end, that is, using the torque output end of the motor to connect one end of the driving rod 9, the driving rod 9, the spring 8, the transmission rod 10 and the cutting saw blade 7 are connected as a whole (forming a flexible cutting rod) to rotate circumferentially, thereby realizing the cutting action of the cutting saw blade 7.

[0028] The flexible cutting rod provided in this embodiment can cut the wall surface of the tunnel wall after drilling along the radial direction of the hole, thereby creating an anchor point on the hole wall surface for grouting and fixing for the anchor rod.

[0029] At the same time, the purpose of the eccentric connection between the transmission rod 10 and the cutting saw blade 7 is that the end of the transmission rod 10 is rigidly connected to the end of the cutting saw blade 7, and the connection position between the end of the transmission rod 10 and the cutting saw blade 7 deviates from the center of the cutting saw blade 7, that is, the eccentric connection between the two can make the cutting range of the cutting saw blade 7 larger during the rotation process without changing the diameter of the cutting saw blade, and the depth of the anchor point on the wall of the hole for fixing the anchor rod for grouting is deeper, the anchor rod is more firmly stuck, and the end bearing force is stronger.

[0030] Under the action of the torque input to the driving input end, the spring 8 of the flexible cutting rod of this embodiment allows the driving rod 9 and the transmission rod 10 to change as follows under the change of the torque magnitude, or it can be understood that the driving rod 9 and the transmission rod 10 are in a state where the torque input by the driving rod 9 increases linearly, then the specific state of the flexible cutting rod can be expressed as follows: The first type is that the driving rod 9 and the transmission rod 10 revolve away from the axis, and the cutting saw blade 7 rotates around its geometric center; The second type is that the driving rod 9 and the transmission rod 10 revolve away from the axis, and the cutting saw blade 7 revolves away from its geometric center; The third type is that the driving rod 9 and the transmission rod 10 rotate circumferentially around the axis, and the cutting saw blade revolves away from its geometric center.

[0031] The purpose is that the tunnel surrounding rock has different stiffness according to its lithology. For hard rock, in order to avoid the cutting rod breaking, the cutting saw blade breaking, or the dislocation and rebound caused by the reaction force of the surrounding rock, more friction should be relied on to cut grooves in the surrounding rock. For soft rock, a rod or cutting saw blade with greater stiffness can be used for cutting to speed up the construction progress. The physical and mechanical properties of the tunnel surrounding rock can be obtained through advanced exploration and indoor tests, and the flexibility of the cutting rod can be selected according to laboratory data in an attempt to control its cutting state.

[0032] Specifically, for hard rock, if a cutting rod with greater rigidity is used directly to cut the surrounding rock, the cutting blade will easily bounce off when it touches the surrounding rock, the cutting blade will have unstable rotation, and problems such as dislocation and displacement will easily occur. At the same time, the cutting blade and the cutting rod are also prone to breakage.

[0033] For hard rock, the cutting rod should be stretched first to increase its flexibility. At this time, the flexible cutting rod revolves in the hollow anchor rod, and the cutting blade rotates around the geometric center (center of the circle), gradually rubbing the surrounding rock. When a certain space is rubbed out, the cutting rod is pushed forward to reduce the flexibility and increase the rigidity. At this time, the cutting saw blade rotates on a larger path, and the work is mainly done by rubbing the surrounding rock, supplemented by impacting the surrounding rock, and the groove in the surrounding rock is further expanded.

[0034] When a larger groove space is cut into the surrounding rock, more parts of the cutting blade can be embedded into it, making the whole harder and the rotation radius larger.

[0035] At this time, although the surrounding rock will rebound when it hits the cutting blade, the cutting blade can be embedded relatively firmly in the gap of the surrounding rock previously rubbed out, the rotation is relatively stable, and it has a certain ability to resist dislocation, displacement, and rebound.

[0036] like Figures 4 to 9 As shown, in this embodiment, the center position of the cutting saw blade 7 or the center position of the end of the transmission rod 10 connected to the cutting saw blade 7 can be connected to the inner top of the anchor rod through a connecting piece, and then an axial force along the driving rod 9 is applied to the other end of the driving rod 9 to adjust the length of the spring 8.

[0037] However, in order to allow the end of the cutting saw blade 7 to have a certain degree of freedom, that is, to enable the cutting saw blade 7 to have a larger rotation radius or an adjustable cutting radius through the input of torque, that is, the three states mentioned above, if the center of the cutting saw blade 7 is connected by a connecting piece so that the cutting saw blade 7 and the inner end of the anchor rod are connected, then the connecting piece must have a defined length to adapt to the cutting radius of the cutting saw blade 7, and the connecting piece may affect the free rotation of the cutting saw blade 7, that is, affect its adjustable cutting radius.

[0038] At the same time, in the later stage of construction in coordination with the anchor rod, after the cutting of the vertical space is completed, the connecting piece needs to be able to be torn off. In this case, when adjusting the length of the spring 8, it is also necessary to consider and control the tension; when installing in the anchor rod, due to the small space in the anchor rod, it is not conducive to assembly, and the connection of the connecting piece limits the rotation of the cutting saw blade 7, which is not conducive to the cutting saw blade having a large degree of freedom, that is, the controllable cutting radius of the cutting saw blade 7.

[0039] This also involves the change in position of the saw blade 7 relative to the cutting opening during the length adjustment of the spring 8 .

[0040] Therefore, if Fig.12 and Fig.13 As shown, in order to realize the stiffness control of the spring 8, that is, to control the expansion and contraction state of the spring 8, this embodiment provides a specific embodiment of a stiffness control device 11: The stiffness control device 11 includes a transmission shaft 111 , one end of which is provided with a driving part 112 , and the other end of the transmission shaft 111 is movably connected to a connecting shaft 113 , and the end of the connecting shaft 113 away from the transmission shaft 111 is movably connected to the end center position of the transmission rod 10 .

[0041] The connecting shaft 113 and the transmission shaft 111 are connected via a ball joint structure or a universal joint structure, and the connecting shaft 113 and the transmission rod 10 are also connected via a ball joint structure or a universal joint structure.

[0042] The purpose is that the active connection between the connecting shaft 113 and the transmission shaft 111 can ensure that the driving rod 9 and the transmission rod 10 are connected based on the spring 8 without limiting the freedom of the transmission rod 10 under the torque input of the driving rod 9. At the same time, it can also adjust the elastic length of the spring 8, and then adjust the overall stiffness of the flexible cutting rod.

[0043] Among them, part of the transmission shaft 111 is arranged inside the driving rod 9 along the axial direction of the driving rod 9, and the driving part 112 is arranged inside the driving rod 9. The driving part 112 is used to drive the transmission shaft 111 to move axially along the transmission rod 10, and the connecting shaft 113 pulls the transmission rod 10 closer to or away from the driving rod 9, so that the spring is compressed or extended.

[0044] The driving part 112 in this embodiment includes a cavity 114 arranged in the driving rod 9, and a sealing piston member 115 is arranged in the cavity 114. The sealing piston member 115 divides the cavity 114 into a balancing cavity 116 and a hydraulic cavity 117. One end of the transmission shaft 111 passes through the hydraulic cavity 117 and is connected to the center of one end surface of the sealing piston member 115. The driving rod 9 corresponding to the hydraulic cavity 117 is provided with an adjusting cavity 118. A sealing screw 119 is arranged in the adjusting cavity 118. The sealing screw 119 is threadedly connected to the inner wall of the adjusting cavity 118, and the adjusting cavity 118 is connected to the hydraulic cavity 117.

[0045] The sealing screw 119 is rotated to compress the liquid in the hydraulic chamber 117 , thereby driving the sealing piston 115 to move along the axial direction of the chamber 114 .

[0046] The balancing chamber 116 is connected to the external environment through the air hole arranged on the driving rod 9 , and its main function is to provide a moving space for the sealing piston 115 .

[0047] Therefore, when the regulating chamber 118 does not act on the hydraulic chamber 117 , that is, after the hydraulic chamber 117 is depressurized, the sealing piston 115 returns to its original position due to the elastic action of the spring 8 .

[0048] This embodiment provides an anchor rod, which is applied to a tunnel anchor rod construction method. The anchor rod includes a hollow rod body 1, one end of the hollow rod body 1 is closed, and the other end is open to form an opening. A cutting opening 2 is arranged on the rod body surface of the hollow rod body 1 near the closed end. The cutting opening 2 is along the circumferential direction of the hollow rod body 1. A plurality of fixed tongue openings 3 are evenly distributed on the rod body of the hollow rod body 1 between the cutting opening 2 and the closed end of the hollow rod body 1.

[0049] This embodiment provides a tunnel anchor construction method, using the flexible cutting rod, including the following steps: Step 100, drilling an anchor installation hole on the tunnel wall according to the anchor design requirements, and installing an anchor with a cutting opening at the end and a plurality of fixing tongue openings evenly distributed on the circumferential surface in the hole; Step 200, using the cutting saw blade of the flexible cutting rod to be sent to a position corresponding to the cutting opening of the anchor rod, cutting the hole wall outside the anchor rod through the cutting opening to cut out a vertical space; The position of the cutting opening is adjusted by rotating the anchor rod so that the cutting saw blade cuts a plurality of vertical spaces on the circumferential surface of the hole, the same number as the plurality of fixing tongue openings; Step 300, adjusting the relative position of the anchor rod along the axial direction of the hole so that the plurality of fixing tongue openings correspond to the plurality of vertical spaces one by one, and then pushing the fixing tongues into the vertical spaces through the fixing tongue openings; Step 400, grouting is performed on the hole to fix the fixing tongue in the vertical space, and the anchor rod is tightly connected to the hole, and finally the hole is sealed.

[0050] After the cutting saw blade using the flexible cutting rod is sent to a position corresponding to the cutting opening of the anchor rod, under the torque input at the driving input end: The flexible cutting rod is limited by the inner diameter of the anchor rod, so that the driving rod and the transmission rod revolve away from the axis, and the cutting saw blade rotates around its geometric center without cutting the hole wall through the cutting opening; When the driving rod and the transmission rod revolve away from the axis, the cutting saw blade revolves away from its geometric center, the revolving radius of the cutting saw blade is greater than the outer diameter of the anchor rod, and the cutting saw blade starts to cut the wall of the hole through the cutting opening; When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting saw blade performs a revolution movement deviating from its geometric center, and in this state, the vertical space cutting of the hole wall is completed.

[0051] According to the formation characteristics of the inner wall of the hole, the length of the spring is stretched or compressed by the stiffness control device to adjust the stiffness of the flexible cutting rod.

[0052] After drilling the anchor installation holes on the tunnel wall according to the anchor design requirements, concrete or polymer slurry is injected into the holes to fix the hole walls.

[0053] The operating principle of tunnel anchors is as follows: In order to enhance the anchoring force of anchor rods under unfavorable geological conditions without increasing the anchoring cost too much, it is necessary to consider the optimization of anchor rod structure and construction process.

[0054] like Figure 1 As shown, the traditional straight anchor rod inserted into the tunnel surrounding rock mainly relies on the friction of the anchor rod side wall to generate tension. Analogous to the "friction pile" in the house construction project, the friction generated by the pile body is very limited. Only by transforming it into an "end-bearing pile" can it generate more "bearing capacity" under a shorter pile body. Therefore, this embodiment adds an anchor piece perpendicular to the pile body at the end.

[0055] For example, the fixing tongue 6 can be based on the actual construction environment. For example, the end surface of the anchor rod is cut on three sides so that the fixing tongue 6 is rectangular, and one side of the fixing tongue 6 is integrally formed with the anchor rod. Alternatively, a rectangular opening, namely the fixing tongue opening, can be cut on the end surface of the anchor rod. During the construction process, the fixing tongue 6 is sent to the corresponding position through the fixing tongue opening, and then slurry is poured and the slurry is solidified, so that the fixing tongue 6 is connected to the anchor rod in a state perpendicular to the anchor rod, which can greatly increase the anchoring effect of the anchor rod and generate a large amount of tensile strength.

[0056] like Figure 2 and Figure 3 As shown, the hollow rod body of the anchor rod has several fixed tongue openings, a cutting opening and a flexible cutting rod. Different anchor rod materials are selected according to the service life design.

[0057] Carbon steel is a commonly used low-cost option suitable for general tunnel projects; alloy steel has higher strength and corrosion resistance and is suitable for projects requiring higher loads and longer life; glass fiber reinforced plastic anchor rods are lightweight, high-strength, corrosion-resistant, non-conductive, and easy to process, making them suitable for projects with poor geology and prone to rust; carbon fiber composite materials have extremely high strength and rigidity and are suitable for projects with higher strength requirements; glass fiber composite materials are relatively low in cost and suitable for general tunnel projects; prestressed concrete uses prestressing technology to enhance the bearing capacity and tensile properties of concrete and is suitable for projects that need to withstand large loads; glass fiber concrete adds glass fibers to concrete to enhance its toughness and durability and is suitable for environments with poor geological conditions or that require corrosion resistance.

[0058] The fixing tongue 6 is relatively small in size, bears a large amount of anchoring force, and has high strength requirements. It can be made of high-strength metal materials such as high-strength alloy steel, titanium alloy, and maraging stainless steel.

[0059] like Figure 3 As shown, the flexible cutting rod is composed of a cutting saw blade 7, a spring 8, and two solid round rods, wherein the two solid round rods are specifically a driving rod 9 and a transmission rod 10.

[0060] The driving rod 9, the transmission rod 10 and the middle spring 8 are rigidly welded.

[0061] The flexible cutting rod here should be made of a material with good elasticity and fatigue resistance.

[0062] For example, stainless steel has excellent corrosion resistance, especially in humid environments. The use of stainless steel can prevent corrosion and maintain the performance and life of spring 8; spring steel is a type of high-carbon steel specially designed for making springs. Spring steel is usually heat treated to improve its elasticity and fatigue resistance. This steel is often used in applications that require frequent bending and rebounding; in some special environments and applications, polymer springs may also be used. These springs are lightweight and not easy to rust, but their elasticity and fatigue resistance may not be as good as metal springs. It is worth noting that the rigid connection position between the solid round rod and the cutting saw blade is not at the geometric center of the cutting blade, but is intentionally eccentrically welded. The material of the cutting saw blade 7 can be made of cemented carbide. The cemented carbide blade is usually made of tungsten-cobalt alloy and has high hardness and wear resistance.

[0063] This enables them to maintain cutting efficiency for a relatively long time and maintain stable cutting performance when facing hard materials such as granite.

[0064] However, carbide inserts are relatively fragile and require careful use to avoid breakage.

[0065] Of course, diamond blades are another common choice for cutting granite. Diamond is one of the hardest materials known and can easily handle hard stones like granite. Diamond blades are usually coated with diamond particles or a diamond cutting layer, which allows the blade to remain sharp while cutting and has good wear resistance.

[0066] Finally, you can also choose ordinary steel blades. The advantage is that the single cost is lower, but because the blades need to be replaced frequently, the overall economic benefits are not obvious.

[0067] Choosing the right blade depends on the specifications and requirements of the cutting saw blade, the hardness and structure of the granite, and factors such as cutting quality and efficiency. Generally speaking, diamond blades are more suitable for applications that require efficient and high-quality cutting, while carbide blades may be more economical, but may require more frequent replacement and maintenance.

[0068] Principle of cutting surrounding rock by flexible cutting rod: In deep tunnel construction, cutting surrounding rock too quickly may cause a series of hazards.

[0069] 1. Rapid cutting of surrounding rock may increase safety risks because rapid removal of surrounding rock may increase the risk of rock collapse, collapse or geological instability, posing a threat to workers and equipment.

[0070] 2. Rapid cutting of surrounding rock may generate a large amount of rock chips, dust and waste, causing pollution to the surrounding environment.

[0071] 3. Cutting the surrounding rock too quickly may lead to a decline in project quality because factors such as geological conditions, stratigraphic changes, and the strength and stability of the surrounding rock are ignored.

[0072] The flexible cutting rod avoids "hard collision" with the surrounding rock and cuts the surrounding rock slowly by slow advance. When the flexible cutting rod is cutting, it specifically goes through the following three stages: Phase 1: Figure 4 As shown, during the center rotation stage of the cutting saw blade, a flexible cutting rod (drive input drive rod 9) is mechanically rotated outside the hole, and the revolution and displacement of the cutting saw blade 7 in the anchor rod are restricted, and it can only rotate in situ along the geometric center.

[0073] like Figure 5As shown, the movement trajectory of the cutting saw blade 7 of the flexible cutting rod is displayed. The cutting saw blade 7 has no displacement, while the anchor rod and the fixing point of the cutting saw blade 7 rotate around the geometric center of the cutting saw blade 7.

[0074] The diameters of the spring 8, the drive rod 9 and the transmission rod 10 of the flexible cutting rod are much smaller than the diameter of the inner cavity of the anchor rod, and there is sufficient space for rotation, so they will revolve along the direction of rotation applied externally.

[0075] The second stage: Figure 6 As shown, during the transition from the first stage to the second stage of the flexible cutting rod, a portion of the cutting saw blade 7 will rub against the surrounding rock along the cutting opening 2 on the anchor rod while rotating, gradually cutting the surrounding rock and generating tiny pores.

[0076] The cutting saw blade 7 has a certain movement space and no longer rotates around the geometric center, but generates a certain revolution speed.

[0077] As attached Figure 7 , showing the motion trajectory of the cutting saw blade 7. The cutting saw blade 7 has a small displacement, and the revolution distance of the driving rod 9, the transmission rod 10 and the fixed point of the cutting saw blade 7 around the cutting saw blade 7 becomes smaller. The revolution of the driving rod 9, the spring 8 and the transmission rod 10 of the flexible cutting rod is weakened, and gradually tends to self-rotation.

[0078] The third stage: Figure 8 As described above, during the stage of the axis rotation of the flexible cutting rod, the surrounding rock outside the cutting opening 2 is cut completely; As attached Fig. 9 , showing the motion trajectory of the cutting saw blade 7. The cutting saw blade 7 revolves around the driving rod, the transmission rod and the fixed point of the cutting saw blade 7, and the flexible cutting rod completely rotates.

[0079] During the specific operation of the flexible cutting rod, after the cutting saw blade using the flexible cutting rod is sent to a position corresponding to the cutting opening of the anchor rod, under the torque input at the driving input end: The flexible cutting rod is limited by the inner diameter of the anchor rod, so that the driving rod and the transmission rod revolve away from the axis, and the cutting saw blade rotates around its geometric center without cutting the hole wall through the cutting opening.

[0080] When the driving rod and the transmission rod revolve away from the axis, the cutting saw blade revolves away from its geometric center, the revolving radius of the cutting saw blade is greater than the outer diameter of the anchor rod, and the cutting saw blade starts to cut the wall of the hole through the cutting opening.

[0081] When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting saw blade performs a revolution movement deviating from its geometric center, and in this state, the vertical space cutting of the hole wall is completed.

[0082] Of course, the three-stage process of the flexible cutting rod is aimed at the situation that the stratum rock density and texture of the practical hole wall of the tunnel are high. The flexible cutting rod has three stages, which enables the flexible cutting rod to use one of the stages to cut rock with different stratum characteristics.

[0083] Specifically, based on the above-mentioned anchor bolt construction method, a more complete on-site construction operation requires: The first step is investigation and design. Conduct geological surveys, analyze the characteristics of the strata, and determine the type and length of the anchor. The structural design takes into account factors such as groundwater level, geological conditions, and tunnel size.

[0084] The second step is preparation. Set up safety fences around the construction area and clear obstacles that may affect construction. Check and ensure that the foundation of the construction site is stable to prevent ground settlement from affecting the stability of the anchor rods.

[0085] The third step is hole drilling. Use a rotary drilling rig or other professional equipment to drill holes on the tunnel wall according to the design requirements. The density and location of the holes need to be determined based on the data of geological survey and structural design.

[0086] Step 4: Clean the holes. Clean the holes by air pressure blowing or other methods to ensure that there is no debris, mud or other debris in the holes.

[0087] The fifth step is grouting. Inject a specific slurry, usually concrete or polymer, into the hole to improve the stability and bearing capacity of the formation.

[0088] Step 6: Anchor rod installation. Insert the anchor rod into the hole through the lifting equipment to ensure the fit with the hole wall. Figure 1 and Fig.11 As shown, the flexible cutting rod is inserted into the hollow interior of the anchor rod, and the cutting saw blade is sent to the cutting opening position.

[0089] The stiffness of the flexible cutting rod is adjusted to suit the project progress and safety requirements, and rotation is applied to one end of the flexible cutting rod so that the cutting saw blade cuts the tunnel surrounding rock to generate a vertical space J1.

[0090] And so on, vertical spaces J1, J2, ..., Jn are cut out according to the required anchoring force.

[0091] The anchor rod is then pulled backward a certain distance so that the fixing tongue 6 is exposed to the vertical spaces J1, J2, ..., Jn. The fixing tongue 6, specifically represented by X1, X2, ..., Xn, is pushed into the vertical spaces J1, J2, ..., Jn in turn, and the anchor rod is locked by the combination of the fixing tongue 6 and the vertical space to achieve enhanced anchoring of the anchor rod end.

[0092] Step 7: Grouting. Use grouting equipment to inject grout into the hole to fill the pores and ensure a tight bond between the anchor rod and the stratum. At the same time, ensure that the fixed tongue 6 pushed into the vertical space, specifically X1, X2, ..., Xn, no longer rebounds, forming a permanent end reinforcement anchor.

[0093] Step 8: Anchor tensioning: Use professional equipment to control the tensioning of the anchor, adjust the tension inside the rod, and increase the friction between the stratum and the anchor.

[0094] Step 9: Seal the hole. Use appropriate materials, such as concrete or waterproof materials, to seal the hole and ensure the integrity of the tunnel wall.

[0095] Step 10: Quality inspection. Perform non-destructive and destructive tests to ensure the quality and structural integrity of the anchor. Measure the tension, check the grouting quality, and record the relevant data.

[0096] Step 11: Record and report. Record key data such as the specific location of the anchor, tension force, grouting conditions, etc. Generate a detailed construction report as a basis for future monitoring and maintenance.

[0097] Step 12: Monitoring and maintenance. Establish a regular monitoring system to track changes in anchors and promptly identify and address potential problems. Perform regular maintenance to ensure the long-term reliability of the anchoring system.

[0098] like Fig.10 As shown, according to the geological characteristics of the inner wall of the hole, the length of the spring is stretched or compressed by the stiffness control device. Its specific applications in the construction process include: The stiffness of the flexible cutting rod can be changed by squeezing or stretching by external force, and the stiffness of the flexible cutting rod will affect the cutting efficiency of the cutting saw blade. The greater the stiffness, the higher the cutting efficiency, but the cutting risk increases; on the contrary, the greater the flexibility, the lower the cutting efficiency, but the cutting risk decreases.

[0099] The main principle is that external force squeezing or stretching will cause the spring to twist. This change can cause the spring's flexibility to increase or decrease. The spring is usually made of metal materials, such as steel.

[0100] When twisted, the lattice structure inside the metal material changes, causing the relative positions of atoms to move, thus affecting the elastic properties of the spring.

[0101] In addition, when the spring is subjected to torsion, its structure will deform, and this deformation will change the spring's geometry and internal stress distribution.

[0102] These changes affect the flexibility of the spring, making it softer or stiffer. Similarly, when the spring is twisted, the material inside the spring will undergo strain, that is, the relative displacement of the molecules or atoms. This strain causes the elastic modulus of the spring to change, which in turn affects the flexibility of the spring.

[0103] Therefore, the change in the spring flexibility of the spring is due to the change in the internal structure and stress state of the material when it is torsionally twisted. This can be used to flexibly adjust the stiffness of the flexible cutting rod to adapt to the project progress and safety requirements.

[0104] At this point, the new anchor rod can significantly increase the anchoring force without increasing the cost of construction too much, and it also has a high degree of flexibility.

[0105] After drilling the anchor installation holes on the tunnel wall according to the anchor design requirements, concrete or polymer slurry is injected into the holes to fix the hole walls.

[0106] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A flexible cutting rod, characterized in that: The invention comprises a driving rod (9), a transmission rod (10) and a cutting saw blade (7), wherein one end of the driving rod (9) forms a driving input end, the other end of the driving rod (9) is connected to the transmission rod (10) via a spring (8), an end of the transmission rod (10) away from the elastic member is connected to the cutting saw blade (7), and the driving rod (9) and the transmission rod (10) share a common axis when not subject to external forces; the transmission rod (10) is eccentrically connected to the cutting saw blade (7); Wherein, under the action of the torque input to the driving input end, the driving rod (9), the spring (8), the transmission rod (10) and the cutting saw blade (7) are connected as a whole and rotate in a circumferential direction, thereby realizing the cutting action of the cutting saw blade (7).

2. A flexible cutting rod according to claim 1, characterized in that: Under the action of torque input to the drive input, the spring (8) allows: The driving rod (9) and the transmission rod (10) revolve in a direction away from the axis, and the cutting saw blade (7) rotates around its geometric center; Alternatively, the driving rod (9) and the transmission rod (10) revolve away from the axis, and the cutting saw blade (7) revolves away from its geometric center; Alternatively, the driving rod (9) and the transmission rod (10) rotate circumferentially around the axis, and the cutting saw blade revolves away from its geometric center.

3. A flexible cutting rod according to claim 2, characterized in that: It also comprises a stiffness control device (11), the stiffness control device (11) comprising a transmission shaft (111), one end of the transmission shaft (111) being provided with a driving portion (112), the other end of the transmission shaft (111) being movably connected to a connecting shaft (113), the end of the connecting shaft (113) being away from the transmission shaft (111) being movably connected to the end center position of the transmission rod (10); Part of the transmission shaft (111) is arranged inside the driving rod (9) along the axial direction of the driving rod (9), the driving portion (112) is arranged inside the driving rod (9), the driving portion (112) is used to drive the transmission shaft (111) to move along the axial direction of the driving rod (10), and the connecting shaft (113) pulls the driving rod (10) closer to or away from the driving rod (9), so that the spring (8) is compressed or extended.

4. A flexible cutting rod according to claim 3, characterized in that: The driving part (112) comprises a cavity (114) arranged in the driving rod (9), a sealing piston member (115) being arranged in the cavity (114), the sealing piston member (115) dividing the cavity (114) into a balancing cavity (116) and a hydraulic cavity (117), one end of the transmission shaft (111) passing through the hydraulic cavity (117) and connected to the center of one end surface of the sealing piston member (115), the driving rod (9) corresponding to the hydraulic cavity (117) being provided with an adjusting cavity (118), a sealing screw (119) being arranged in the adjusting cavity (118), the sealing screw (119) being threadedly connected to the inner wall of the adjusting cavity (118), and the adjusting cavity (118) being connected to the hydraulic cavity (117); The sealing screw (119) is rotated to compress the liquid in the hydraulic chamber (117), thereby driving the sealing piston (115) to move axially along the chamber (114).

5. A method for constructing a tunnel anchor bolt, using the flexible cutting rod according to any one of claims 1 to 4, characterized in that: The steps include: Step 100, drilling an anchor installation hole on the tunnel wall according to the anchor design requirements, and installing an anchor with a cutting opening at the end and a plurality of fixing tongue openings evenly distributed on the circumferential surface in the hole; Step 200, using the cutting saw blade of the flexible cutting rod to be sent to a position corresponding to the cutting opening of the anchor rod, cutting the hole wall outside the anchor rod through the cutting opening to cut out a vertical space; The position of the cutting opening is adjusted by rotating the anchor rod so that the cutting saw blade cuts a plurality of vertical spaces on the circumferential surface of the hole, the same number as the plurality of fixing tongue openings; Step 300, adjusting the relative position of the anchor rod along the axial direction of the hole so that the plurality of fixing tongue openings correspond to the plurality of vertical spaces one by one, and then pushing the fixing tongues into the vertical spaces through the fixing tongue openings; Step 400, grouting is performed on the hole to fix the fixing tongue in the vertical space, and the anchor rod is tightly connected to the hole, and finally the hole is sealed.

6. A tunnel anchor construction method according to claim 5, characterized in that: After the cutting saw blade using the flexible cutting rod is sent to a position corresponding to the cutting opening of the anchor rod, under the torque input at the driving input end: The flexible cutting rod is limited by the inner diameter of the anchor rod, so that the driving rod and the transmission rod revolve away from the axis, and the cutting saw blade rotates around its geometric center without cutting the hole wall through the cutting opening; When the driving rod and the transmission rod revolve away from the axis, the cutting saw blade revolves away from its geometric center, the revolving radius of the cutting saw blade is greater than the outer diameter of the anchor rod, and the cutting saw blade starts to cut the wall of the hole through the cutting opening; When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting saw blade performs a revolution movement deviating from its geometric center, and in this state, the vertical space cutting of the hole wall is completed.

7. A tunnel anchor construction method according to claim 6, characterized in that: According to the formation characteristics of the inner wall of the hole, the length of the spring is stretched or compressed by the stiffness control device to adjust the stiffness of the flexible cutting rod.

8. A tunnel anchor construction method according to claim 6, characterized in that: After drilling the anchor installation holes on the tunnel wall according to the anchor design requirements, concrete or polymer slurry is injected into the holes to fix the hole walls.

9. An anchor rod, applied to the tunnel anchor rod construction method according to claim 5, characterized in that: The anchor rod comprises a hollow rod body (1), one end of the hollow rod body (1) is closed, and the other end is open to form an opening, the cutting opening (2) is arranged on the rod body surface of the hollow rod body (1) close to the closed end, the cutting opening (2) is arranged along the circumferential direction of the hollow rod body (1), and a plurality of the fixing tongue openings (3) are evenly distributed on the rod body of the hollow rod body (1) between the cutting opening (2) and the closed end of the hollow rod body (1).

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