A flexible cutting rod, an anchor rod and a construction method for tunnel anchor rods

Abstract

The present invention discloses a flexible cutting rod, an anchor rod and a construction method for a tunnel anchor rod, which includes a driving rod, a transmission rod and a cutting saw blade. The driving rod is connected to the transmission rod through a spring, and one end of the transmission rod is connected to the cutting saw blade. Through driving input, the whole connected by the driving rod, the spring, the transmission rod and the cutting saw blade makes a circumferential rotation; drill a hole for installing the anchor rod, and install the anchor rod with a cutting opening and a plurality of fixing tongue openings at the end in the hole; use the cutting saw blade of the flexible cutting rod to cut a vertical space corresponding to the fixing tongue opening on the hole wall surface, so that a plurality of fixing tongue openings correspond to a plurality of vertical spaces one by one, and then push the fixing tongue into the vertical space through the fixing tongue opening; fix the fixing tongue in the vertical space, grout the hole to make the anchor rod closely connected to the hole, and finally seal the hole. The present invention enables the anchor rod to be applied to different stratum structures, increases the anchoring force of the anchor rod, and makes the construction of the anchor rod faster and more efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel bolt anchoring construction, and particularly relates to a flexible cutting rod, a bolt and a tunnel bolt construction method. Background Art

[0002] In tunnel engineering, bolts play an important role. They can not only enhance the geological stability and the stability of the support structure, but also reduce surface deformation, provide construction support, and extend the service life of the tunnel. However, the existing tunnel bolt construction methods and the anchoring force of bolt structures are affected by geological conditions, and specific geological conditions may lead to insufficient anchoring force of the bolts.

[0003] For example, 1. When the tunnel passes through soft soil layers, the shear strength and bearing capacity of these soils are low. Bolts may not be able to obtain sufficient frictional resistance or support force in soft soil layers, resulting in insufficient anchoring force. 2. When there are rock joints, these joints are fissures or cracks. If the direction of these joints is perpendicular or nearly perpendicular to the bolt direction, it may lead to insufficient anchoring force. In this case, the bolts 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 of the rock and the anchoring effect. Bolts near the fault zone may have problems with insufficient anchoring force due to the instability of the rock. 4. If the tunnel passes underground through a water-saturated layer, the penetration of water will weaken the shear strength of the soil or rock, thereby reducing the anchoring force of the bolts. Or when there is a sandy soil layer containing a large amount of fine particles, there may be a loss phenomenon during the bolt anchoring, resulting in a weakened anchoring force.

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

[0005] When the existing tunnel bolt construction has insufficient anchoring force, increasing the length of the bolts can improve their frictional resistance and support force in the formation. By using longer bolts, it can be ensured that they are anchored in deeper stable formations. Increasing the number and density of the bolts can improve the overall anchoring effect. However, both have requirements for the bolt material strength, geological environment, and construction environment, and not all engineering conditions are suitable.

[0006] Furthermore, in particularly harsh geological conditions, it can be considered to reinforce the formation, such as by grouting reinforcement, rock shotcreting, etc., to improve the stability and anchoring force of the formation. However, this method greatly increases the construction operation and easily leads to an increase in construction costs.

[0007] Therefore, during the construction of existing tunnel bolts, there are problems such as the lack of anchoring force of bolts caused by using the existing bolt construction method to deal with various soil layer structures, and the increase in construction operation complexity and construction cost caused by other bolt fixing methods. Summary of the Invention

[0008] The purpose of the present invention is to provide a bolt for tunnels and its construction method to solve the technical problem in the prior art that the anchoring force is missing due to the inability to deal with various soil layer structures during the construction of existing tunnel bolts.

[0009] To solve the above technical problems, the present invention specifically provides the following technical solutions:

[0010] A flexible cutting rod includes a driving rod, a transmission rod, and a cutting saw blade. 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 spring is connected to the cutting saw blade, and the driving rod and the transmission rod are coaxial without external force; the transmission rod is eccentrically connected to the cutting saw blade;

[0011] Wherein, under the action of the torque input to the driving input end, the whole connected by the driving rod, the spring, the transmission rod, and the cutting saw blade rotates circumferentially to realize the cutting action of the cutting saw blade.

[0012] As a preferred solution of the present invention, under the action of the torque input to the driving input end, the spring allows:

[0013] The driving rod and the transmission rod make a revolution deviating from the axis, and the cutting saw blade rotates around its geometric center;

[0014] Or, the driving rod and the transmission rod make a revolution deviating from the axis, and the cutting saw blade makes a revolution deviating from its geometric center;

[0015] Or, the driving rod and the transmission rod rotate circumferentially around the axis, and the cutting saw blade makes a revolution deviating from its geometric center.

[0016] As a preferred solution of the present invention, it further 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 to a connecting shaft. The end of the connecting shaft away from the transmission shaft is movably connected to the center position of the end of the transmission rod;

[0017] Among them, a 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 transmission rod, and the connecting shaft pulls the transmission rod closer to or away from the driving rod, so that the spring is compressed or elongated.

[0018] As a preferred solution of the present invention, the driving part includes a cavity arranged inside the driving rod, a sealing piston part is arranged inside the cavity, the sealing piston part divides the cavity into a balance 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 face of the sealing piston part, an adjusting cavity is arranged on the driving rod corresponding to the hydraulic cavity, a sealing screw rod is arranged inside the adjusting cavity, the sealing screw rod is threadedly connected with the inner wall of the adjusting cavity, and the adjusting cavity communicates with the hydraulic cavity;

[0019] Among them, by rotating the sealing screw rod to compress the liquid in the hydraulic cavity, the sealing piston part is driven to move along the axial direction of the cavity.

[0020] The present invention provides a construction method for tunnel bolts, using the flexible cutting rod, including the following steps:

[0021] Step 100: Drill bolt installation holes on the tunnel wall surface according to the bolt design requirements, and install bolts with cutting openings at the ends and a plurality of fixed tongue openings evenly distributed on the circumferential surface in the holes;

[0022] Step 200: Send the cutting saw blade of the flexible cutting rod to a position corresponding to the cutting opening of the bolt, and cut the hole wall surface outside the bolt through the cutting opening to cut out a vertical space;

[0023] By rotating the bolt, adjust the position of the cutting opening, so that the cutting saw blade cuts out a plurality of vertical spaces on the circumferential surface of the hole, and the number of the vertical spaces is the same as that of the plurality of fixed tongue openings;

[0024] Step 300: Adjust the relative position of the bolt along the axial direction of the hole, so that the plurality of fixed tongue openings correspond to the plurality of vertical spaces one by one, and then push the fixed tongues into the vertical spaces through the fixed tongue openings;

[0025] Step 400: Grout the hole, fix the fixed tongue in the vertical space, and make the bolt tightly connected with the hole, and finally seal the hole.

[0026] As a preferred solution of the present invention, after sending the cutting saw blade of the flexible cutting rod to a position corresponding to the cutting opening of the bolt, under the torque input at the driving input end:

[0027] The flexible cutting rod is restricted by the inner diameter of the anchor rod, causing the driving rod and the transmission rod to revolve around an axis deviating from the axis, and the cutting saw blade to rotate around its geometric center in a self-rotation motion that does not cut the hole wall through the cutting opening;

[0028] When the driving rod and the transmission rod revolve around an axis deviating from the axis, and the cutting saw blade makes a revolution motion deviating from its geometric center, and the revolution radius of the cutting saw blade is greater than the outer diameter of the anchor rod, the cutting saw blade starts to cut the wall of the hole through the cutting opening;

[0029] When the driving rod and the transmission rod rotate circumferentially around the axis, and the cutting saw blade makes a revolution motion deviating from its geometric center, the vertical space of the hole wall is cut in this state.

[0030] As a preferred embodiment 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.

[0031] As a preferred embodiment of the present invention, after drilling the anchor rod installation hole in accordance with the design requirements of the anchor rod on the tunnel wall surface, concrete or polymer slurry is injected into the hole to fix the hole wall surface.

[0032] The present invention provides an anchor rod applied to the tunnel anchor rod construction method described above. 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. A cutting opening is provided on the rod body surface of the hollow rod body near the closed end. The cutting opening is along the circumferential direction of the hollow rod body, and a plurality of fixed 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.

[0033] The present invention has the following beneficial effects compared with the prior art:

[0034] (1) The end structure of the anchor rod provided by the present invention exerts the rod body friction force after the construction is completed, and at the same time, fully exerts the end bearing force through the fixed tongue structure, greatly improving the anchoring effect of the anchor rod under adverse geological conditions.

[0035] (2) The anchor rod provided by the present invention can realize different working states of the cutting saw blade by adjusting the spring structure, and then cut the tunnel hole wall surface, which is suitable for various formation structure characteristics of the tunnel and completes more efficient cutting.

[0036] (3) The overall structure of the anchor rod provided by the present invention and the flexible cutting rod used in cooperation in construction is simple and convenient for large-scale use in engineering.

[0037] (4) The present invention provides a construction method for tunnel anchoring bolts. The overall construction process is simple, and on-site construction can be quickly mastered, accelerating the project progress and improving construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0039] Figure 1 It is a schematic longitudinal sectional structure diagram of the bolt relative to the tunnel wall surface in an embodiment of the present invention;

[0040] Figure 2 It is a schematic structure diagram of the bolt in an embodiment of the present invention;

[0041] Figure 3 It is a schematic structure diagram of the flexible cutting rod in an embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of the flexible cutting rod in the first stage state in an embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of the cutting saw blade rotation state of the flexible cutting rod in the second stage state in an embodiment of the present invention;

[0044] Figure 6 It is a schematic diagram of the flexible cutting rod in the second stage state in an embodiment of the present invention;

[0045] Figure 7 It is a schematic diagram of the cutting saw blade rotation state of the flexible cutting rod in the second stage state in an embodiment of the present invention;

[0046] Figure 8 It is a schematic diagram of the flexible cutting rod in the third stage state in an embodiment of the present invention;

[0047] Figure 9 It is a schematic diagram of the cutting saw blade rotation state of the flexible cutting rod in the third stage state in an embodiment of the present invention;

[0048] Figure 10 It is a schematic diagram of the spring adjustment structure of the flexible cutting rod in an embodiment of the present invention;

[0049] Figure 11 It is a schematic flow diagram of a construction method for tunnel bolts in an embodiment of the present invention;

[0050] Figure 12Schematic diagram of the stiffness control device for the flexible cutting rod according to an embodiment of the present invention;

[0051] Figure 13 Schematic diagram of the driving part structure according to an embodiment of the present invention.

[0052] The reference numerals in the figure are respectively represented as follows:

[0053] 1 - Hollow rod body; 2 - Cutting opening; 3 - Fixed tongue opening; 4 - Tunnel surrounding rock where the hole is located; 5 - Hole; 6 - Fixed tongue; 7 - Cutting saw blade; 8 - Spring; 9 - Driving rod; 10 - Transmission rod; 11 - Stiffness control device;

[0054] 111 - Transmission shaft; 112 - Driving part; 113 - Connecting shaft; 114 - Cavity; 115 - Sealing piston part; 116 - Balance cavity; 117 - Hydraulic cavity; 118 - Adjusting cavity; 119 - Sealing screw. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] As Figures 1 to 11 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 spring 8 is connected to the cutting saw blade 7, and the driving rod 9 and the transmission rod 10 are coaxial without external force; the transmission rod 10 is eccentrically connected to the cutting saw blade 7.

[0057] Among them, under the action of the torque input to the driving input end, that is, using the torque output end of the motor or the motor to connect one end of the driving rod 9, then the whole connected by the driving rod 9, the spring 8, the transmission rod 10 and the cutting saw blade 7 (forming a flexible cutting rod) rotates circumferentially, realizing the cutting action of the cutting saw blade 7.

[0058] The flexible cutting rod provided by this embodiment can cut the wall surface along the radial direction of the hole in the tunnel wall surface after drilling, so as to create an anchor point for grouting and fixing on the hole wall surface for the fixation of the anchor bolt.

[0059] 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 of 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, with the eccentric connection, when the diameter of the cutting saw blade remains unchanged, during the rotation of the cutting saw blade 7, the cutting range is larger, the depth of the anchor points for grouting fixation on the wall surface of the hole for fixing the anchor rod is deeper, the anchor rod is clamped more firmly, and the end bearing capacity is stronger.

[0060] Under the action of the torque input to the drive input end of the flexible cutting rod of this embodiment, the spring 8 allows the drive rod 9 and the transmission rod 10 to change as follows with the change of the torque magnitude. Or it can be understood that when the torque input to the drive rod 9 increases linearly, the specific state of the flexible cutting rod can be expressed as the following three types:

[0061] First, the drive rod 9 and the transmission rod 10 perform a revolution deviating from the axis, and the cutting saw blade 7 rotates around its geometric center.

[0062] Second, the drive rod 9 and the transmission rod 10 perform a revolution deviating from the axis, and the cutting saw blade 7 performs a revolution deviating from its geometric center.

[0063] Third, the drive rod 9 and the transmission rod 10 rotate circumferentially around the axis, and the cutting saw blade performs a revolution deviating from its geometric center.

[0064] The purpose is that the stiffness of the tunnel surrounding rock varies according to its lithology. For hard rock, in order to avoid the cutting rod breaking, the cutting saw blade being damaged, or being displaced or rebounding due to the reaction force of the surrounding rock, more reliance should be placed on friction to cut grooves in the surrounding rock. For soft rock, a rod or cutting saw blade with a larger 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 laboratory tests. The flexibility of the cutting rod is selected according to the laboratory data to control its cutting state.

[0065] Specifically, for hard rock, if a cutting rod with a relatively large rigidity is directly used to cut the surrounding rock, the cutting blade is easily bounced off when it touches the surrounding rock, the rotation of the cutting blade is unstable, and problems such as dislocation and displacement are likely to occur. At the same time, the cutting blade and the cutting rod are also prone to breakage.

[0066] 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, push the cutting rod forward to make the flexibility smaller and the rigidity larger. At this time, the rotation path of the cutting saw blade is larger, and the work is mainly done by rubbing the surrounding rock and supplemented by hitting the surrounding rock, and the groove in the surrounding rock is further enlarged.

[0067] When the surrounding rock is cut to form a larger groove space, a larger part of the cutting blade can be embedded into it, making the whole harder and having a larger rotation radius.

[0068] At this time, although the impact of the surrounding rock on the cutting blade will cause rebound, the cutting blade can be relatively firmly embedded in the gap of the surrounding rock rubbed out before, and the rotation situation is relatively stable, having a certain ability to resist dislocation, displacement and rebound.

[0069] As Figures 4 to 9 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 connecting the cutting saw blade 7 can be connected to the inner top of the bolt 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.

[0070] However, in order to enable the end of the cutting saw blade 7 to have a certain degree of freedom, that is, through the input of torque, the cutting saw blade 7 can have a larger rotation radius or a controllable cutting radius, namely the above three states. If the center of the cutting saw blade 7 is connected by a connecting piece so that the cutting saw blade 7 is connected to the inner end of the bolt, then the connecting piece must have a defined length to adapt to the cutting radius of the cutting saw blade 7, and at the same time, the connecting piece may affect the free rotation of the cutting saw blade 7, that is, affect its controllable cutting radius.

[0071] At the same time, in the later stage of the construction in cooperation with the bolt, after the vertical space is cut, the connecting piece needs to be broken. Then, in this connection method, the pulling force needs to be considered and controlled when adjusting the length of the spring 8; when installed in the bolt, due to the small space inside the bolt, 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.

[0072] At the same time, it also involves the position change of the cutting saw blade 7 relative to the cutting opening during the adjustment of the length of the spring 8.

[0073] Therefore, as Figure 12 and Figure 13 shown, in this embodiment, in order to realize the stiffness control of the spring 8, that is, to control the expansion and contraction state of the spring 8, a specific embodiment of a stiffness control device 11 is provided:

[0074] The stiffness control device 11 includes a transmission shaft 111, one end of the transmission shaft 111 is provided with a driving part 112, the other end of the transmission shaft 111 is movably connected with a connecting shaft 113, and the end of the connecting shaft 113 far from the transmission shaft 111 is movably connected with the center position of the end of the transmission rod 10.

[0075] Among them, the connecting shaft 113 and the transmission shaft 111 are connected by a ball joint structure or a universal joint structure, and the connecting shaft 113 and the transmission rod 10 are also connected by a ball joint structure or a universal joint structure.

[0076] The purpose is that the movable connection between the connecting shaft 113 and the transmission shaft 111 can ensure that, on the basis of the connection of the driving rod 9 and the transmission rod 10 by the spring 8, the freedom degree of the transmission rod 10 under the torque input of the driving rod 9 is not restricted, and at the same time, the elastic length of the spring 8 can be adjusted, thereby adjusting the overall stiffness of the flexible cutting rod.

[0077] Among them, a part of the transmission shaft 111 is arranged inside the driving rod 9 along the axial direction of the driving rod 9, the driving part 112 is arranged inside the driving rod 9, and the driving part 112 is used to drive the transmission shaft 111 to move along the axial direction of the transmission rod 10. The connecting shaft 113 pulls the transmission rod 10 to approach or move away from the driving rod 9, so that the spring is compressed or elongated.

[0078] The driving part 112 in this embodiment includes a cavity 114 arranged inside the driving rod 9. A sealing piston part 115 is arranged inside the cavity 114. The sealing piston part 115 divides the cavity 114 into a balance 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 face of the sealing piston part 115. An adjusting cavity 118 is arranged on the driving rod 9 corresponding to the hydraulic cavity 117. A sealing screw rod 119 is arranged inside the adjusting cavity 118. The sealing screw rod 119 is threadedly connected to the inner wall of the adjusting cavity 118, and the adjusting cavity 118 communicates with the hydraulic cavity 117.

[0079] Among them, by rotating the sealing screw rod 119 to compress the liquid in the hydraulic cavity 117, the sealing piston part 115 is driven to move along the axial direction of the cavity 114.

[0080] Among them, the balance cavity 116 communicates with the external environment through an air hole arranged on the driving rod 9, and its main function is to provide a moving space for the sealing piston part 115.

[0081] Therefore, when the adjusting cavity 118 does not act on the hydraulic cavity 117, that is, after the hydraulic cavity 117 is depressurized, the sealing piston part 115 returns to its initial position through the elastic action of the spring 8.

[0082] This embodiment provides an anchor rod, which is applied to the 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. Cutting openings 2 are arranged on the rod body surface of the hollow rod body 1 near the closed end. The cutting openings 2 are 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 openings 2 and the closed end of the hollow rod body 1.

[0083] This embodiment provides a construction method for tunnel bolts. Using the flexible cutting rod, it includes the following steps:

[0084] Step 100: Drill bolt installation holes on the tunnel wall surface according to the bolt design requirements, and install bolts with cutting openings at the ends and a plurality of fixed tongue openings evenly distributed on the circumferential surface in the holes;

[0085] Step 200: Send the cutting blade of the flexible cutting rod to a position corresponding to the cutting opening of the bolt, and cut the hole wall surface outside the bolt through the cutting opening to cut out a vertical space;

[0086] Adjust the position of the cutting opening by rotating the bolt, so that the cutting blade cuts out a plurality of vertical spaces on the circumferential surface of the hole, and the number of the vertical spaces is the same as that of the plurality of fixed tongue openings;

[0087] Step 300: Adjust the relative position of the bolt along the axial direction of the hole, so that the plurality of fixed tongue openings correspond to the plurality of vertical spaces one by one, and then push the fixed tongues into the vertical spaces through the fixed tongue openings;

[0088] Step 400: Grout the hole, fix the fixed tongues in the vertical spaces, and make the bolt tightly connected to the hole, and finally seal the hole.

[0089] After the cutting blade of the flexible cutting rod is sent to a position corresponding to the cutting opening of the bolt, under the torque input at the driving input end:

[0090] The flexible cutting rod is restricted by the inner diameter of the bolt, so that the driving rod and the transmission rod make a revolution deviating from the axis, and the cutting blade makes a self-rotation action around its geometric center without cutting the hole wall surface through the cutting opening;

[0091] When the driving rod and the transmission rod make a revolution deviating from the axis, the cutting blade makes a revolution deviating from its geometric center, and the revolution radius of the cutting blade is greater than the outer diameter of the bolt, and the cutting blade starts to cut the hole wall surface through the cutting opening;

[0092] When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting blade makes a revolution deviating from its geometric center, and in this state, the vertical space of the hole wall surface is cut.

[0093] According to the formation characteristics of the inner wall of the hole, stretch or compress the length of the spring through the stiffness control device to adjust the stiffness of the flexible cutting rod.

[0094] After drilling the bolt installation holes on the tunnel wall surface according to the bolt design requirements, inject concrete or polymer slurry into the holes to fix the hole wall surface.

[0095] The operating principle of the anchor rod for tunnels is as follows:

[0096] In order to enhance the anchoring force of the anchor rod under adverse geological conditions without excessive increase in the anchoring cost, it is necessary to consider optimizing the anchor rod structure and construction process.

[0097] As Figure 1 shown, the traditional straight anchor rod is inserted into the surrounding rock of the tunnel, and the tensile force is mainly generated by the friction force on the side wall of the anchor rod. By analogy with the "friction pile" in building engineering, the friction force generated by the pile body is very limited. Only by transforming it into an "end-bearing pile" can more "bearing capacity" be generated under a shorter pile length. Therefore, in this embodiment, an anchor is added perpendicular to the pile body at the end.

[0098] For example, the fixed tongue 6, and the fixed tongue 6 can be cut on three sides of the end surface of the anchor rod according to the actual construction environment, so that the fixed tongue 6 is rectangular. One side of the fixed tongue 6 is integrally formed with the anchor rod, or a rectangular opening, i.e., the fixed tongue opening, can be cut on the end surface of the anchor rod. During the construction process, the fixed tongue 6 is sent to the corresponding position through the fixed tongue opening, and then through the perfusion of the slurry and the solidification of the slurry, the fixed 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 capacity.

[0099] As Figure 2 and Figure 3 shown, there are several fixed tongue openings, a cutting opening and a flexible cutting rod in the hollow rod body of the anchor rod. Different anchor rod materials are selected according to the service life design.

[0100] Carbon steel is a commonly used low-cost option and is suitable for general tunnel projects; alloy steel has higher strength and corrosion resistance and is suitable for projects with higher loads and longer service lives; glass fiber reinforced plastic anchor rods have characteristics such as light weight, high strength, corrosion resistance, non-conductivity, and easy processing, and are suitable for projects with poor geology and prone to corrosion; carbon fiber composite materials have extremely high strength and stiffness and are suitable for projects with high strength requirements; glass fiber composite materials have lower costs and are suitable for general tunnel projects; prestressed concrete enhances the bearing capacity and tensile performance of concrete through prestress technology and is suitable for projects that need to bear large loads; glass fiber concrete adds glass fiber to the concrete to enhance its toughness and durability and is suitable for environments with poor geological conditions or requiring corrosion resistance.

[0101] The fixed tongue 6 has a small volume and bears a large amount of anchoring force. For very high strength requirements, high-strength metal materials such as high-strength alloy steel, titanium alloy, and maraging stainless steel can be used for production.

[0102] As Figure 3As shown, the flexible cutting rod consists of a cutting saw blade 7, a spring 8, and two solid round rods, specifically a driving rod 9 and a transmission rod 10.

[0103] The driving rod 9 and the transmission rod 10 are rigidly welded to the middle spring 8.

[0104] For the flexible cutting rod here, materials with good elasticity and fatigue resistance should be selected.

[0105] For example, stainless steel has excellent corrosion resistance. Especially in a humid environment, using stainless steel can prevent corrosion and maintain the performance and lifespan of the spring 8; spring steel is a type of high-carbon steel specifically designed for manufacturing springs. Spring steel is usually heat-treated to improve its elasticity and fatigue resistance. This type of steel is commonly 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 prone to rust, but their elasticity and fatigue resistance may be inferior to metal springs. It should be noted 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 deliberately eccentrically welded. The material of the cutting saw blade 7 can be selected as cemented carbide. Cemented carbide blades are usually made of tungsten-cobalt alloy and have very high hardness and wear resistance.

[0106] This enables them to maintain the cutting efficiency for a relatively long time and, when facing hard materials such as granite, to maintain stable cutting performance.

[0107] However, cemented carbide blades are relatively fragile and need to be used carefully to avoid breakage.

[0108] Of course, diamond blades are another common choice for cutting granite. Diamond is one of the hardest materials known currently and can easily handle hard stone materials such as granite. Diamond blades are usually coated with diamond particles or a diamond cutting layer, which enables the blades to remain sharp during cutting and have good wear resistance.

[0109] Finally, ordinary steel blades can also be selected. Their advantage is that the single cost is relatively low, but due to the need to frequently replace the blades, the overall economic efficiency is not obvious.

[0110] Selecting the appropriate blade depends on factors such as the specifications and requirements of the cutting saw blade, the hardness and structure of the granite, and the cutting quality and efficiency. Usually, diamond blades are more suitable for applications that require high-efficiency and high-quality cutting, while cemented carbide blades may be more cost-effective, but may require more frequent replacement and maintenance.

[0111] Principle of the flexible cutting rod for cutting surrounding rock:

[0112] In deep tunnel construction, cutting surrounding rock too quickly may cause a series of hazards.

[0113] 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.

[0114] 2. Rapid cutting of surrounding rock may generate a large amount of rock chips, dust and waste, causing pollution to the surrounding environment.

[0115] 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.

[0116] 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:

[0117] 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.

[0118] like Figure 5 As 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.

[0119] 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.

[0120] 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 to produce tiny pores.

[0121] The cutting saw blade 7 has a certain movement space and no longer rotates around the geometric center, but generates a certain revolution speed.

[0122] 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.

[0123] The third stage: As Figure 8 described, during the stage of the flexible cutting rod rotating around its axis, the surrounding rock outside the cutting opening 2 is completely cut;

[0124] As shown in the Figure 9 appendix, the movement trajectory of the cutting saw blade 7 is shown. The cutting saw blade 7 revolves around the fixed point of the driving rod, the transmission rod and the cutting saw blade 7, and the flexible cutting rod rotates completely.

[0125] During the specific working process of the flexible cutting rod, after the cutting saw blade of the flexible cutting rod is sent to the position corresponding to the cutting opening of the anchor rod, under the torque input at the driving input end:

[0126] The flexible cutting rod is restricted by the inner diameter of the anchor rod, causing the driving rod and the transmission rod to make a revolution deviating from the axis, and the cutting saw blade makes a self-rotation action around its geometric center without cutting through the cutting opening to cut the hole wall surface.

[0127] When the driving rod and the transmission rod make a revolution deviating from the axis, the cutting saw blade makes a revolution deviating from its geometric center, and the revolution 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 surface of the hole through the cutting opening.

[0128] When the driving rod and the transmission rod rotate circumferentially around the axis, the cutting saw blade makes a revolution deviating from its geometric center, and in this state, the vertical space of the hole wall surface is cut.

[0129] Of course, the above three-stage process of the flexible cutting rod is for the case where the formation rock density of the hole wall surface used in the tunnel is large and the texture is hard. And the flexible cutting rod having three-stage states enables the flexible cutting rod to use one of the stage states to cut rock masses with different formation characteristics.

[0130] Specifically, based on the above construction method of the anchor rod, a more complete on-site construction operation requires:

[0131] The first step, investigation and design. Conduct geological investigation, analyze formation characteristics, and determine the type and length of the anchor rod. The structural design takes into account factors such as the groundwater level, geological conditions, and tunnel dimensions.

[0132] The second step, preparation work. Set up safety fences around the construction area and clear obstacles that may affect the construction. Check and ensure the stability of the foundation of the construction site to prevent formation settlement from affecting the stability of the anchor rod.

[0133] The third step, hole drilling. Use a rotary drilling rig or other professional equipment to drill holes on the tunnel wall surface according to the design requirements. The density and position of the drill holes need to be determined according to the data of geological investigation and structural design.

[0134] Step 4, clean the holes. Clean the holes by air pressure blowing or other methods to ensure that there are no sundries such as gravel and mud in the holes.

[0135] Step 5, grout injection. Inject a specific grout, usually concrete or polymer, into the holes to improve the stability and bearing capacity of the formation.

[0136] Step 6, anchor installation. Insert the anchor into the hole through a hoisting device to ensure its fit with the hole wall. As shown in the appendix Figure 1 and Figure 11 Insert the flexible cutting rod into the hollow interior of the anchor, and send the cutting saw blade to the cutting opening position.

[0137] Adjust the stiffness of the flexible cutting rod to adapt to the project progress and safety requirements. Apply rotation at one end of the flexible cutting rod to make the cutting saw blade cut the surrounding rock of the tunnel, generating a vertical space J1.

[0138] And so on, cut out vertical spaces J1, J2, …, Jn according to the required anchoring force.

[0139] Then pull the anchor back a certain distance so that the fixing tongues 6 are exposed at the positions of the vertical spaces J1, J2, …, Jn. Push the fixing tongues 6, specifically represented as X1, X2, …, Xn, into the vertical spaces J1, J2, …, Jn in sequence to lock the anchor through the combination of the fixing tongues 6 and the vertical spaces, realizing the end enhanced anchoring of the anchor.

[0140] Step 7, grouting. Use a grouting device to inject grout into the holes to fill the pores and ensure a tight bond between the anchor and the formation. At the same time, ensure that the fixing tongues 6 pushed into the vertical space, specifically X1, X2, …, Xn, do not rebound, forming a permanent end enhanced anchoring.

[0141] Step 8, anchor tensioning. Use professional equipment to control the tensioning of the anchor, adjust the internal tension of the rod, and increase the friction between the formation and the anchor.

[0142] Step 9, seal the hole opening. Use appropriate materials, such as concrete or waterproof materials, to seal the hole opening to ensure the integrity of the tunnel wall surface.

[0143] Step 10, quality inspection. Conduct non-destructive and destructive tests to ensure the quality and structural integrity of the anchor. Measure the tensile force, check the grouting quality, and record relevant data.

[0144] Step 11, record and report. Record key data such as the specific position of the anchor, the tensile force, and the grouting situation. Generate a detailed construction report as a basis for future monitoring and maintenance.

[0145] Step 12: Monitoring and Maintenance. Establish a regular monitoring system to track the changes of the anchor bolts, detect and handle potential problems in a timely manner. Conduct regular maintenance work to ensure the long-term reliability of the anchoring system.

[0146] As Figure 10 shown, according to the formation characteristics of the inner wall of the hole, stretch or compress the length of the spring through the stiffness control device. Its specific applications during construction include:

[0147] The stiffness of the flexible cutting rod can be changed by external extrusion or stretching, 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 danger increases; on the contrary, the greater the flexibility, the lower the cutting efficiency, but the cutting danger decreases.

[0148] The main principle is that external extrusion or stretching will cause the spring to twist, and this change can lead to an increase or decrease in the flexibility of the spring. The spring is usually made of metal materials, such as steel.

[0149] When being twisted, the lattice structure inside the metal material will change, resulting in the relative positions of atoms moving, thus affecting the elastic characteristics of the spring.

[0150] In addition, when the spring is subjected to a torsional force, its structure will deform, and this deformation will change the geometric shape and internal stress distribution of the spring.

[0151] These changes will affect the flexibility of the spring, making it softer or harder. Similarly, when being twisted, the material inside the spring will undergo strain, that is, the relative displacement between molecules or atoms. This strain will cause a change in the elastic modulus of the spring, thereby affecting the flexibility of the spring.

[0152] Therefore, the change in the spring flexibility of the spring is due to the changes in the internal structure and stress state of the material when being twisted. By utilizing this point, the stiffness of the flexible cutting rod can be flexibly adjusted to adapt to the engineering progress and safety requirements.

[0153] So far, this new type of anchor bolt can significantly increase the anchoring force without increasing too much cost and construction cost, and also has a high degree of flexibility.

[0154] After drilling the anchor bolt installation holes on the tunnel wall surface according to the design requirements of the anchor bolts, inject concrete or polymer slurry into the holes to fix the wall surface of the holes.

[0155] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling 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 spring (8) 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); 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; 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).

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 tunnel anchor construction method using the flexible cutting rod according to claim 1, 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: Use the cutting saw blade of the flexible cutting rod to be sent to a position corresponding to the cutting opening of the anchor rod, and cut 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.

4. A tunnel anchor construction method according to claim 3, 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.

5. A tunnel anchor construction method according to claim 4, 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.

6. A tunnel anchor construction method according to claim 4, 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.

7. An anchor rod, applied to the tunnel anchor rod construction method according to claim 3, 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 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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