Mechanical expansion type anchor rod system based on composite material and construction method of mechanical expansion type anchor rod system

Abstract

The invention belongs to the field of underground engineering and tunnel shield construction, and discloses a mechanical expansion type anchor rod system based on a composite material and a construction method of the mechanical expansion type anchor rod system. The hollow main rod body is of a hollow tubular structure; the center driving pull rod is concentrically arranged in an inner cavity of the hollow main rod body in a penetrating mode. The front end of the central driving pull rod extends to the outer side of the front end of the hollow main rod body; the flexible fish belly expansion assembly is arranged at the front end of the hollow main rod body and arranged on the outer side of the front end of the center driving pull rod in a sleeving mode. The center driving pull rod is used for applying acting force in the axis direction of the hollow main rod body to the flexible fish belly expansion assembly, so that the flexible fish belly expansion assembly is forced to bend in the direction perpendicular to the axis direction of the hollow main rod body, and a spindle-shaped or spherical expansion head is formed. According to the method, the high anchoring force and the machinability required by shield starting end reinforcement can be achieved at the same time, the method is adaptive to the engineering scene of shield starting end reinforcement, and the safety and efficiency of shield construction are improved.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering and tunnel shield construction technology, and relates to underground engineering support technology, particularly to a mechanical expansion anchor system based on composite materials and its construction method. Background Technology

[0002] Shield tunneling is a commonly used and efficient tunneling technology in engineering fields such as underground rail transit and municipal tunnels. The reinforcement of the shield launching end is a key link in the entire construction process, which is directly related to construction safety and project quality. In order to improve the bearing capacity and stability of the soil at the shield launching end, anchor bolt reinforcement technology is generally used in actual projects. The surface soil is connected and fixed to the deep stable soil through anchor bolts, and prestress is applied to restrain soil deformation, creating safe underlying conditions for shield launching.

[0003] Currently, in shield tunneling start-up end reinforcement projects, glass fiber reinforced polymer (GFRP) anchors or steel mechanical expansion anchors are commonly used. However, existing anchors cannot simultaneously meet the dual core requirements of high anchoring force and easy cutting for shield tunneling start-up end reinforcement.

[0004] Specifically, while GFRP anchors offer easy cutting capability, their relatively smooth surface means their anchoring force relies primarily on the bond between the grout, the anchor, and the soil. In challenging geological conditions such as soft fill, silty soil, or water-rich sand layers, the grout bonding effect is significantly reduced, resulting in anchoring force typically only around 40% of that of traditional steel anchors. This fails to provide sufficient prestress to effectively constrain soil deformation, making it difficult to guarantee end-face soil stability and leaving a safety hazard of end-face instability. In contrast, traditional steel mechanical expansion anchors utilize high-strength steel for their core components, such as the expansion arm, tie rod, and hinge joint, which cannot be cut by the tunnel boring machine (TBM) cutterhead. Therefore, they are often equipped with complex recyclable mechanisms to recover the anchor components after reinforcement. However, in the high-pressure underground grouting environment, cement grout easily seeps into the gaps of the recycling mechanism and hardens, causing it to jam or fail. If recycling fails, the remaining steel anchor head will directly collide with the TBM cutterhead, severely damaging it and leading to significant economic losses and project delays. Summary of the Invention

[0005] To address the technical problems existing in the prior art, this invention provides a mechanically expandable anchor bolt system based on composite materials and its construction method, in order to solve the technical problem that existing anchor bolts cannot simultaneously meet the dual core requirements of high anchoring force and easy cutting for shield tunneling start-up end reinforcement.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a mechanical expansion anchor system based on composite materials. The mechanical expansion anchor system based on composite materials is made of non-metallic composite materials and includes a hollow main rod, a central drive tie rod, and a flexible fish belly expansion component. The hollow main rod is a hollow tubular structure; The central drive rod is concentrically inserted into the internal cavity of the hollow main rod; wherein, the front end of the central drive rod extends to the outer side of the front end of the hollow main rod. The flexible fish-belly expansion component is disposed at the front end of the hollow main rod and sleeved on the outer side of the front end of the central drive rod; wherein, the central drive rod is used to apply a force to the flexible fish-belly expansion component along the axial direction of the hollow main rod, so as to force the flexible fish-belly expansion component to buckle perpendicular to the axial direction of the hollow main rod, forming a spindle-shaped or spherical enlarged head.

[0007] Furthermore, the hollow main rod is made of glass fiber reinforced polymer, and both the inner and outer surfaces of the hollow main rod are provided with threaded structures.

[0008] Furthermore, an annular grouting gap is provided between the inner wall of the hollow main rod and the outer wall of the central drive tie rod.

[0009] Furthermore, the central drive rod is made of a solid rod material of glass fiber reinforced polymer or aramid fiber cable.

[0010] Furthermore, the flexible fish belly expansion assembly includes a first component end, a plurality of flexible thin-walled arched pieces, and a second component end; The end of the first component is fixed to the front end of the hollow main rod and passes through the outside of the central drive rod; the end of the second component is fixed to the front end of the central drive rod. Several of the flexible thin-walled arch plates are disposed between the end of the first component and the end of the second component, and are evenly distributed on the outside of the central drive rod.

[0011] Furthermore, the first component end and several of the flexible thin-walled arches are made of high-toughness nylon, polyurethane, or fiber-reinforced composite materials; the second component end is made of engineering plastics.

[0012] Furthermore, the outer surface of the flexible thin-walled arch sheet is integrally formed with several anti-slip tooth structures.

[0013] Furthermore, the inner diameter of the first component end is adapted to the inner diameter of the hollow main rod; the outer diameter of the second component end is greater than or equal to the inner diameter of the hollow main rod.

[0014] Furthermore, the diameter of the spindle-shaped or spherical enlarged head is 2.5-4.0 times the outer diameter of the hollow main rod.

[0015] This invention also provides a construction method for a mechanically expandable anchor system based on composite materials, comprising: The hollow main rod, the central drive tie rod, and the flexible fish belly expansion assembly are assembled to form the anchor bolt body; The anchor bolt body is installed into the pre-constructed anchor bolt hole; during the installation of the anchor bolt body, the flexible fish belly expansion component is in a contracted state. At the pre-constructed anchor hole opening, an axial tension is applied to the central drive tie rod to force the flexible fish belly expansion component to buckle perpendicular to the axis of the hollow main rod, forming a spindle-shaped or spherical enlarged head; wherein, the spindle-shaped or spherical enlarged head serves as a mechanical anchoring end, compressing the surrounding soil.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The mechanically expandable anchor system based on composite materials provided by this invention, through the synergistic design of materials and structure, combines the high anchoring force and easy cutting required for shield tunneling start-up end reinforcement, adapting to the engineering needs of shield tunneling start-up end reinforcement and improving construction safety and efficiency. Specifically, the anchor system is made entirely of non-metallic composite materials, replacing the metal material of traditional steel anchors. This inherent material characteristic allows the entire anchor system to be directly cut by the shield machine blades, eliminating the need for complex recovery mechanisms and effectively preventing equipment damage, construction delays, and economic losses caused by anchor residue. Secondly, by introducing a flexible fish-belly expansion component, force is applied along the axis of the hollow main rod via a central drive tie rod, forcing the component to buckle perpendicular to the axis and form a spindle-shaped or spherical enlarged head. This spindle-shaped or spherical enlarged head can mechanically embed itself into the surrounding soil, compared to GFRP anchors that rely solely on grouting for anchoring force. This invention significantly improves the bonding strength between the anchor bolt and the soil. Even in unfavorable strata such as soft fill, silty soil, or water-rich sand layers, it overcomes the limitations of reduced grout bonding effect, providing anchoring force far exceeding that of GFRP anchor bolts. It effectively applies prestress to constrain soil deformation, ensuring the bearing capacity and stability of the soil at the shield tunneling start-up end, and eliminating the safety hazard of end instability. Furthermore, the hollow tubular structure of the hollow main rod, combined with the concentrically inserted central drive tie rod, achieves structural separation between the tie rod's force application and the rod's load-bearing capacity. This ensures the stability of the force application when the drive expansion component forms the enlarged head, while maintaining good structural strength in the hollow main rod. This provides structural support for the overall anchor bolt's anchoring effect and cutting characteristics, effectively adapting to the engineering requirements of shield tunneling start-up end reinforcement, and improving construction safety and efficiency. This invention possesses advantages such as simple structure, reliable construction, and no residual risks, providing a safe, efficient, and economical technical solution for shield tunneling start-up end reinforcement.

[0017] Furthermore, the hollow main rod is made of glass fiber reinforced polymer, which not only makes it easy to be cut by the cutterhead of the tunnel boring machine, but also ensures the structural strength and deformation resistance of the hollow main rod, adapting to the load-bearing requirements of the shield tunneling start-up end reinforcement. At the same time, threaded structures are set on the inner and outer surfaces of the hollow main rod, which can significantly increase the contact area and bonding force between the hollow main rod and the grouting slurry and the surrounding soil, thereby improving the bonding and anchoring effect between the hollow main rod and the stratum. It can also increase the contact area with the grouting slurry, strengthening the overall anchoring foundation of the anchor rod from a structural level.

[0018] Furthermore, by setting an annular grouting gap between the inner wall of the hollow main rod and the outer wall of the central drive tie rod, a dedicated grout flow channel is provided for the grouting operation, allowing the grout to fully fill the gaps in the soil around the anchor rod, achieving all-round bonding and anchoring between the anchor rod and the soil, and improving the overall bonding effect.

[0019] Furthermore, the central drive tie rod is made of a solid rod of glass fiber reinforced polymer or aramid fiber cable, ensuring that the tie rod can be cut by the tunnel boring machine cutterhead without the need for an additional recycling structure, thus avoiding the risk of metal component residue. Secondly, the solid rod of GFRP material has good axial tensile strength, while the aramid fiber cable has high toughness and fatigue resistance. Both can meet the axial force requirements for driving the buckling deformation of the flexible fish belly expansion component, and can stably transmit the force to form the expansion head.

[0020] Furthermore, the flexible fish belly expansion assembly adopts a combination structure of the first component end, several flexible thin-walled arch plates and the second component end, so that the flexible fish belly expansion assembly forms a lantern-like structure. When the central drive rod applies force along the axis, the force can be evenly transmitted to each flexible thin-walled arch plate through the second component end, so that each arch plate buckles and deforms synchronously, ensuring the uniformity and symmetry of the expansion head forming, and avoiding the problem of insufficient embedding force caused by uneven local deformation.

[0021] Furthermore, several anti-slip tooth structures are integrally formed on the outer surface of the flexible thin-walled arch plate. When the flexible fish-belly expansion component buckles to form an enlarged head, the anti-slip tooth structure can be directly embedded into the surrounding soil, forming a dual anchoring effect of mechanical interlocking and surface contact embedding. This significantly increases the friction and embedding force between the enlarged head and the soil, effectively preventing relative slippage between the enlarged head and the soil, and thus significantly improving the mechanical interlocking force of the anchor system. At the same time, the anti-slip tooth structure is an integrally formed structure, which can maintain the anti-slip interlocking effect for a long time.

[0022] Furthermore, by designing the inner diameter of the first component end to be compatible with the inner diameter of the hollow main rod, precise docking and secure connection between the first component end and the front end of the hollow main rod can be ensured, avoiding connection gaps or loosening caused by dimensional deviations, and ensuring the stability of force transmission between the main rod and the expansion component. The outer diameter of the second component end is greater than or equal to the inner diameter of the hollow main rod. When the central drive rod applies force to move the second component end toward the main rod, the second component end can effectively limit and apply force to the flexible thin-walled arch plate, forcing the arch plate to buckle and deform outward, preventing the arch plate from shrinking inward and causing the enlarged head to fail to form.

[0023] Furthermore, the diameter of the spindle-shaped or spherical enlarged head is designed to be 2.5-4.0 times the outer diameter of the hollow main rod, so that the flexible fish-belly expansion component can form a sufficient contact area and embedding volume with the surrounding soil, which greatly improves the mechanical efficiency and meets the high anchoring force requirements of shield tunneling start-up end reinforcement. At the same time, it can avoid excessive disturbance to the surrounding soil during the enlarged head forming process, prevent the end soil from cracking or becoming unstable, and take into account both anchoring effect and soil protection. It is suitable for engineering scenarios of shield tunneling start-up end reinforcement and can stably provide sufficient prestress to constrain soil deformation in different strata.

[0024] The construction method of the mechanical expansion anchor system based on composite materials provided by this invention has all the advantages of the aforementioned mechanical expansion anchor system based on composite materials. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the expansion state of a mechanically expandable anchor system based on composite materials provided for an embodiment; Figure 2 A schematic diagram of the contracted state of a mechanically expandable anchor system based on composite materials provided for an embodiment; Figure 3 This is a schematic diagram illustrating the working principle of the flexible fish belly expansion component in the embodiment; Figure 4 This is a schematic diagram of the failure condition of the anchor system provided in the embodiment when subjected to the cutting action of a tunnel boring machine.

[0027] Among them, 1 is the hollow main rod, 2 is the central drive tie rod, 3 is the flexible fish belly expansion component, 4 is the orifice locking device; 5 is the concrete retaining structure, 6 is the soil to be constructed, 7 is the shield machine cutterhead, 8 is the cutting debris; 301 is the end of the first component, 302 is the flexible thin-walled arch plate, 303 is the end of the second component, 304 is the anti-slip tooth structure; 701 is the cutting tool. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0029] Before describing the specific embodiments of this application, some of the technical terms involved in the embodiments of this application are explained as follows: The tunnel boring machine (TBM) starting point refers to the area where the TBM first enters the ground from the foundation pit. The stability of the soil in this area directly determines whether the TBM can start smoothly. If the soil at the starting point collapses or deforms excessively, it will not only cause the TBM to get stuck, but may also lead to safety accidents such as ground subsidence and damage to surrounding buildings.

[0030] This invention provides a mechanically expandable anchor system based on composite materials. The mechanically expandable anchor system based on composite materials is made of non-metallic composite materials and includes a hollow main rod 1, a central drive rod 2, and a flexible fish-belly expansion component 3. The hollow main rod 1 is a hollow tubular structure. The central drive rod 2 is concentrically inserted into the internal cavity of the hollow main rod 1. The front end of the central drive rod 2 extends to the outer side of the front end of the hollow main rod 1.

[0031] The flexible fish belly expansion component 3 is disposed at the front end of the hollow main rod 1 and sleeved on the outer side of the front end of the central drive rod 2; wherein, the central drive rod 2 is used to apply a force to the flexible fish belly expansion component 3 along the axial direction of the hollow main rod 1, so as to force the flexible fish belly expansion component 3 to buckle perpendicular to the axial direction of the hollow main rod 1, forming a spindle-shaped or spherical enlarged head.

[0032] In the above embodiments, the mechanically expandable anchor system based on composite materials is entirely made of non-metallic composite materials, giving the entire anchor system the characteristic of being directly cut by the tunnel boring machine (TBM) blades. This eliminates the need for complex recovery mechanisms, effectively avoiding the risk of failure associated with traditional steel anchors that require complex recovery mechanisms and are prone to failure. It also prevents residual anchor heads from damaging the TBM cutterhead. Secondly, the anchor system employs a combined structure of a hollow main rod, a central drive tie rod, and a flexible fish-belly expansion component. The central drive tie rod moves axially within the hollow main rod, applying force to the flexible fish-belly expansion component, causing it to buckle perpendicular to the main rod's axis to form a spindle-shaped or spherical expansion head. This significantly improves the mechanical interlocking force between the anchor and the soil, thereby ensuring high anchoring force of the anchor system. The invention has a simple structure and can effectively adapt to the engineering requirements of reinforcing the starting end of a TBM, ensuring the safety and efficiency of TBM construction.

[0033] The following specific embodiments further illustrate the mechanical expansion anchor system based on composite materials provided by the present invention: Example As attached Figure 1-2 As shown, this embodiment provides a mechanically expandable anchor bolt system based on composite materials, including a hollow main rod 1, a central drive tie rod 2, a flexible fish-belly expansion assembly 3, and an orifice locking device 4.

[0034] The hollow main rod 1, as the main load-bearing component of the anchor system, extends to a predetermined position in the soil to be constructed through pre-constructed anchor holes. The hollow main rod 1 adopts a hollow tubular structure and is made of glass fiber reinforced polymer (GFRP). The use of GFRP in the hollow main rod 1 provides both ease of cutting by the tunnel boring machine cutterhead and ensures structural strength and deformation resistance. Preferably, both the inner and outer surfaces of the hollow main rod 1 are provided with threaded structures. By providing threaded structures on both the inner and outer surfaces of the hollow main rod 1, the contact area and bonding force between the hollow main rod 1 and the grouting slurry and surrounding soil can be significantly increased, thereby improving the bonding and anchoring effect between the hollow main rod and the stratum soil. It also increases the contact area with the grouting slurry, structurally strengthening the overall anchoring foundation of the anchor.

[0035] The central drive rod 2 is concentrically inserted into the internal cavity of the hollow main rod 1, and the central drive rod 2 can move along the axial direction of the hollow main rod 1 to act as a force transmission component, applying a force along the axial direction of the hollow main rod 1 to the flexible fish belly expansion assembly 3; specifically, the axis of the central drive rod 2 coincides with the axis of the hollow main rod 1, the front end of the central drive rod 2 extends to the outer side of the front end of the hollow main rod 1, and the end of the central drive rod 2 extends to the outer side of the tail end of the hollow main rod 1; wherein, the tail end of the hollow main rod 1 and the tail end of the central drive rod 2 both extend to the outer side of the pre-constructed anchor bolt hole opening.

[0036] The central drive rod 2 is made of solid GFRP or aramid fiber cable, which ensures that the central drive rod 2 can be cut by the tunnel boring machine cutterhead without the need for an additional recycling structure, thus avoiding the risk of metal component residue. Secondly, the solid GFRP rod has good axial tensile strength. In addition, the aramid fiber cable has high toughness and fatigue resistance. Therefore, the central drive rod 2 meets the axial force requirements for driving the buckling deformation of the flexible fish belly expansion component 4, and can stably transmit the force to form the expansion head.

[0037] An annular grouting gap is provided between the inner wall of the hollow main rod 1 and the outer wall of the central drive tie rod 2, and the annular grouting gap is filled with cement grout. By providing an annular grouting gap between the inner wall of the hollow main rod 1 and the outer wall of the central drive tie rod 2, a dedicated grout flow channel is provided for the grouting operation, so that the grout can be fully filled into the gaps of the soil around the anchor rod, thereby achieving all-round bonding and anchoring between the anchor rod system and the soil and improving the overall bonding effect.

[0038] The flexible fish-belly expansion component 3 is disposed at the front end of the hollow main rod 1 and sleeved on the outer side of the front end of the central drive rod 2. When the central drive rod 2 applies a force along the axial direction of the hollow main rod 1 to the flexible fish-belly expansion component 3, it can force the flexible fish-belly expansion component 3 to buckle perpendicular to the axial direction of the hollow main rod 1, forming a spindle-shaped or spherical enlarged head. The spindle-shaped or spherical enlarged head can form a mechanical embedding effect with the surrounding soil. Preferably, the diameter of the spindle-shaped or spherical enlarged head is equal to the outer diameter of the hollow main rod 1. 2.5-4.0 times; The diameter of the spindle-shaped or spherical enlarged head is designed to be 2.5-4.0 times the outer diameter of the hollow main rod 1, so that the flexible fish belly expansion component 3 forms a sufficient contact area and embedded solid volume with the surrounding soil, which greatly improves the mechanical efficiency and meets the high anchoring force requirements of shield tunneling start-up end reinforcement; at the same time, it can avoid excessive disturbance to the surrounding soil during the enlarged head forming process, prevent the end soil from cracking or becoming unstable, and take into account both anchoring effect and soil protection. It is suitable for engineering scenarios of shield tunneling start-up end reinforcement and can stably provide sufficient prestress to constrain soil deformation in different strata.

[0039] The flexible fish-belly expansion component 3 includes a first component end 301, several flexible thin-walled arch plates 302, and a second component end 303. The first component end 301 is fixed to the front end of the hollow main rod 1 and passes through the outside of the central drive rod 2. The inner diameter of the first component end 301 is adapted to the inner diameter of the hollow main rod 1. The second component end 303 is fixed to the front end of the central drive rod 2, and the outer diameter of the second component end 301 is greater than or equal to the inner diameter of the hollow main rod 1 to support the expanded component. The flexible thin-walled arch pieces 302 are all disposed between the first component end 301 and the second component end 303, and are evenly distributed on the outside of the central drive rod 2; specifically, a plurality of the flexible thin-walled arch pieces 302 are arranged in a ring array on the outside of the front end of the central drive rod 2, and are placed between the first component end 301 and the second component end 303; wherein, one end of the flexible thin-walled arch piece 302 is connected to the first component end 301, and the other end of the flexible thin-walled arch piece 302 is connected to the second component end 303.

[0040] In this embodiment, a plurality of anti-slip tooth structures 304 are integrally formed on the outer surface of the flexible thin-walled arch plate 302; preferably, the anti-slip tooth structures 304 are located in the middle part of the flexible thin-walled arch plate 302; by integrally forming a plurality of anti-slip tooth structures 304 on the outer surface of the flexible thin-walled arch plate 302, when the flexible fish belly expansion component 3 buckles to form an enlarged head, the anti-slip tooth structures 304 can be directly embedded in the surrounding soil, forming a dual anchoring effect of mechanical interlocking and surface contact embedding, which greatly increases the friction and embedding force between the enlarged head and the soil, effectively preventing relative slippage between the enlarged head and the soil, and thus significantly improving the mechanical interlocking force of the anchor system; at the same time, the anti-slip tooth structure is an integrally formed structure, which can maintain the anti-slip interlocking effect for a long time.

[0041] It should be noted that in the flexible fish belly expansion assembly 3, the first component end 301, several flexible thin-walled arch pieces 302, and the second component end combine to form a lantern-like structure. When the central drive rod 2 applies force along the axis, the force can be evenly transmitted to each flexible thin-walled arch piece 302 through the second component end 303, so that each flexible thin-walled arch piece 302 buckles and deforms synchronously, ensuring the uniformity and symmetry of the hammer-shaped or spherical expansion head formation, and avoiding the problem of insufficient embedding force caused by uneven local deformation.

[0042] The first component end 301 and several of the flexible thin-walled arch plates 302 are made of high-toughness nylon, polyurethane or fiber-reinforced composite materials to give the flexible thin-walled arch plates 302 good buckling deformation capacity and resilience. They can be smoothly deformed under axial force to form a hammer-shaped or spherical enlarged head, and can maintain structural integrity after deformation, forming a stable mechanical interlocking effect with the surrounding soil. At the same time, the high-toughness nylon, polyurethane or fiber-reinforced composite materials have good impact resistance and wear resistance, and are suitable for complex underground construction environments.

[0043] The second component end 303 is made of engineering plastic, which can ensure that the second component end 303 has sufficient structural strength and connection stability, and can stably transmit the axial force of the central drive rod 2, avoiding force failure due to deformation or breakage of the second component end 303.

[0044] The orifice locking device 4 is installed on the outside of the pre-constructed anchor hole and sleeved on the outside of the tail end of the hollow main rod 1; wherein, the orifice locking device 4 is used to lock the relative position of the central drive rod 2 and the hollow main rod 1.

[0045] Construction methods and working principles: The construction process of the mechanical expansion anchor system based on composite materials described in this embodiment is as follows: Step 1: Drill anchor holes in the soil at the starting end of the shield tunnel to obtain pre-constructed anchor holes; one end of the pre-constructed anchor hole is connected to the concrete retaining structure 5 (such as a diaphragm wall) at the shield tunnel construction end, and the other end of the pre-constructed anchor hole extends to a preset position in the soil 6 to be constructed at the starting end of the shield tunnel.

[0046] Step 2: Assemble the hollow main rod 1, the central drive tie rod 2, and the flexible fish belly expansion component 3 to form the anchor rod body.

[0047] Step 3: Install the anchor bolt body into the pre-constructed anchor bolt hole; during the installation of the anchor bolt body, the flexible fish-belly expansion component 3 is in a retracted state to ensure that the anchor bolt body can be unobstructedly inserted into the pre-constructed anchor bolt hole, as shown in the attached diagram. Figure 2 As shown; it should be noted that when the flexible fish belly expansion component 3 is in the contracted state, several flexible thin-walled arch pieces 302 are attached to the outer surface of the central drive rod 2 along the axial direction of the central drive rod 2, ensuring that the anchor body can be inserted into the bottom of the pre-constructed anchor hole.

[0048] Step 4: At the pre-constructed anchor hole opening, apply axial tension to the central drive tie rod 2 to force the flexible fish belly expansion component 3 to buckle perpendicular to the axis of the hollow main rod 1, forming a spindle-shaped or spherical enlarged head; wherein, the spindle-shaped or spherical enlarged head serves as a mechanical anchoring end, compressing the surrounding soil.

[0049] Specifically, after the anchor bolt body is installed in the preset position, a tensioning device is used to clamp the central drive tie rod 2 at the pre-constructed anchor bolt hole opening to apply tension; at this time, as shown in the attached... Figure 3 As shown, the central drive rod 2 drives the second component end 303 to slide along the axial direction of the central drive rod 2 toward the pre-constructed anchor hole opening; when the second component end 303 slides, the flexible fish belly expansion component 3 is squeezed and buckles perpendicular to the axial direction of the hollow main rod 1; that is, when the second component end 303 slides, it forces the flexible thin-walled arch plate to undergo radial buckling, forming a spindle-shaped or spherical enlarged head; the radial support force generated by the spindle-shaped or spherical enlarged head strongly squeezes the soil to be constructed 6, forming a soil compaction zone, thereby significantly improving the physical and mechanical properties of the end soil; at the same time, the anti-slip tooth structure 304 penetrates into the soil to be constructed 6, providing mechanical interlocking.

[0050] Step 5: When the flexible fish-belly expansion component 3 reaches the preset expansion state, the orifice locking device 4 is installed on the outside of the pre-constructed anchor hole and sleeved on the outside of the tail end of the hollow main rod 1; wherein, the orifice locking device 4 is set on the outside of the concrete retaining structure; the orifice locking device 4 is used to lock the relative position of the center drive rod 2 and the hollow main rod 1, and maintain the open state of the flexible fish-belly expansion component 3 and the compressive force on the soil.

[0051] Step 6: Connect the grouting equipment to the tail end of the hollow main rod 1; use the grouting equipment to allow cement grout to flow through the annular grouting gap between the hollow main rod 1 and the central drive tie rod 2 to the bottom of the pre-constructed anchor hole, so as to fill the internal cavity of the flexible fish belly expansion component 3 and penetrate into the surrounding soil 6 to be constructed; after the cement grout solidifies, the hollow hammer-shaped or spherical expansion head is formed into a solid composite material solid stone body to completely lock the shape of the expansion head.

[0052] It should be noted that during the subsequent initial excavation of the tunnel boring machine (TBM), the TBM cutterhead 7 and its cutting blades 701 come into contact with the mechanically expandable anchor system. Because the mechanically expandable anchor system is made of non-metallic composite material, its shear strength is much lower than that of steel. This allows the TBM cutterhead 7 to directly cut the hollow main rod 1, the central drive tie rod 2, and the flexible fish-belly expansion assembly 3, forming cutting fragments 8, as shown in the attached diagram. Figure 4 As shown, the broken cutting fragments 8 are discharged with the slag, avoiding entanglement on the tunnel boring machine cutterhead 7 and preventing damage to the cutting tools 701.

[0053] The mechanical expansion anchor system based on composite materials described in this embodiment utilizes a hollow main rod 1, a central drive tie rod 2, and a flexible fish-belly expansion component 3 to form the anchor body. A locking device 4 is used to lock the hollow main rod 1 and the central drive tie rod 2 within the anchor body. In the anchor body, the hollow main rod 1 acts as the anchor skeleton and grouting channel, while the central drive tie rod 2 transmits force to the flexible fish-belly expansion component 3. The flexible fish-belly expansion component 3, located at the front end of the hollow main rod 1, deforms under stress to form a spindle-shaped or spherical enlarged head, thereby creating a reliable mechanical engagement with the soil 6 to be constructed.

[0054] In this embodiment, by pulling the central drive rod 2 inside the orifice, the second component end 303 is driven to retract towards the orifice. Since the positions of the hollow main rod 1 and the first component end 301 are fixed, the flexible thin-walled arch plate 302 located between the first component end 301 and the second component end 303 is subjected to axial pressure. Based on the buckling characteristics of the high-toughness material of the flexible thin-walled arch plate 302, a radial expansion process similar to that of a lantern structure is formed, creating a spindle-shaped or spherical enlarged head. The anti-slip tooth structure 304 on the flexible thin-walled arch plate 302 is deeply embedded in the soil 6 to be constructed, forming a huge end resistance. At the same time, grouting is performed using the annular grouting gap between the hollow main rod 1 and the central drive rod 2 to solidify the hollow spindle-shaped or spherical enlarged head into a solid mechanical expansion head.

[0055] The mechanical expansion anchor system based on composite materials described in this invention utilizes the mechanical properties of composite materials to design a flexible buckling structure to achieve non-metallic mechanical expansion, enabling the tunnel boring machine cutterhead to directly cut through. A flexible fish-belly expansion component 3 is placed at the front end of the hollow main rod 1. Through the axial pull of the central drive rod 2, the flexible fish-belly expansion component 3 is forced to radially buckle and expand, forming a spindle-shaped or spherical enlarged head to compress the surrounding soil and generate a high anchoring force. An annular grouting gap is set between the inner wall of the hollow main rod 1 and the outer wall of the central drive rod 2 as a coaxial grouting channel. After the grout solidifies, the hollow flexible expansion head is locked into a solid rock body. This invention effectively solves the problem of insufficient gripping force of traditional GFRP anchors in soft soil layers, while avoiding the risk of cutterhead collapse caused by the failure of steel anchor recovery, achieving efficient, safe, and active reinforcement of the tunnel boring machine's starting end.

[0056] In this invention, by forcing the flexible fish-belly expansion component 3 to buckle perpendicular to the axis of the hollow main rod 1, a spindle-shaped or spherical expansion head is formed. The formed mechanical expansion head is directly embedded in the soil, generating an active soil compaction effect and forming an active reinforcement effect, significantly improving the anchoring force of the anchor system. Preferably, the pull-out resistance of the anchor system can be increased by 2-3 times, which is particularly suitable for soft soil layers. The expansion process of the flexible fish-belly expansion component 3 is mechanically controlled, and the degree of expansion can be accurately judged according to the displacement of the central drive rod 2. Secondly, by setting an annular grouting gap between the inner wall of the hollow main rod 1 and the outer wall of the central drive rod 2, the coaxial grouting design ensures that the interior of the expansion head can be filled with grout, thereby forming a strong anchor body like reinforced concrete of composite material. The mechanical expansion anchor system based on composite material is made of non-metallic composite material, which is safe and easy to cut. It does not need to be removed when the tunnel boring machine starts, and the tunnel boring machine cutterhead can directly cut through it, completely eliminating the risk of cutter head collapse.

[0057] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A mechanically expandable anchor system based on composite materials, characterized in that, The mechanical expansion anchor system based on composite materials is made of non-metallic composite materials and includes a hollow main rod (1), a central drive tie rod (2) and a flexible fish belly expansion component (3). The hollow main rod (1) is a hollow tubular structure; The central drive rod (2) is concentrically inserted into the internal cavity of the hollow main rod (1); wherein the front end of the central drive rod (2) extends to the outer side of the front end of the hollow main rod (1); The flexible fish belly expansion component (3) is disposed at the front end of the hollow main rod (1) and sleeved on the outer side of the front end of the central drive rod (2); wherein, the central drive rod (2) is used to apply a force to the flexible fish belly expansion component (3) along the axial direction of the hollow main rod (1) to force the flexible fish belly expansion component (3) to buckle perpendicular to the axial direction of the hollow main rod (1) to form a spindle-shaped or spherical enlarged head.

2. The mechanically expandable anchor system based on composite materials according to claim 1, characterized in that, The hollow main rod (1) is made of glass fiber reinforced polymer, and both the inner and outer surfaces of the hollow main rod (1) are provided with threaded structures.

3. The mechanically expandable anchor system based on composite materials according to claim 1, characterized in that, An annular grouting gap is provided between the inner wall of the hollow main rod (1) and the outer wall of the central drive tie rod (2).

4. A mechanically expandable anchor system based on composite materials according to claim 1, characterized in that, The central drive rod (2) is made of a solid rod made of glass fiber reinforced polymer or aramid fiber cable.

5. A mechanically expandable anchor system based on composite materials according to claim 1, characterized in that, The flexible fish belly expansion component (3) includes a first component end (301), a plurality of flexible thin-walled arch plates (302), and a second component end (303). The first component end (301) is fixed to the front end of the hollow main rod (1) and sleeved on the outside of the central drive rod (2); the second component end (303) is fixed to the front end of the central drive rod (2); Several of the flexible thin-walled arch plates (302) are disposed between the first component end (301) and the second component end (303) and are evenly distributed on the outside of the central drive rod (2).

6. A mechanically expandable anchor system based on composite materials according to claim 5, characterized in that, The first component end (301) and several of the flexible thin-walled arches (302) are made of high-toughness nylon, polyurethane or fiber-reinforced composite material; the second component end (303) is made of engineering plastic.

7. A mechanically expandable anchor system based on composite materials according to claim 5, characterized in that, The outer surface of the flexible thin-walled arch plate (302) is integrally formed with several anti-slip tooth structures (304).

8. A mechanically expandable anchor system based on composite materials according to claim 5, characterized in that, The inner diameter of the first component end (301) is adapted to the inner diameter of the hollow main rod (1); the outer diameter of the second component end (301) is greater than or equal to the inner diameter of the hollow main rod (1).

9. A mechanically expandable anchor system based on composite materials according to claim 1, characterized in that, The diameter of the spindle-shaped or spherical enlarged head is 2.5-4.0 times the outer diameter of the hollow main rod (1).

10. A construction method for a mechanically expandable anchor system based on composite materials as described in any one of claims 1-9, characterized in that, include: The hollow main rod (1), the central drive tie rod (2) and the flexible fish belly expansion component (3) are assembled to form the anchor rod body; The anchor body is installed into the pre-constructed anchor hole; during the installation of the anchor body, the flexible fish belly expansion component (3) is in a contracted state; At the pre-constructed anchor hole opening, an axial tension is applied to the central drive tie rod (2) to force the flexible fish belly expansion component (3) to buckle in a direction perpendicular to the axis of the hollow main rod (1), forming a spindle-shaped or spherical enlarged head; wherein, the spindle-shaped or spherical enlarged head serves as a mechanical anchoring end, squeezing the surrounding soil.

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