A umbrella rib shape memory alloy combined grouting anchor rod and construction method

Abstract

The umbrella-shaped shape memory alloy combined grouting anchor rod and construction method, which belongs to the technical field of surrounding rock anchoring, comprises an anchor rod, an anchorage device, an umbrella-shaped shape memory alloy, a metal sleeve and an adhesive agent. The anchor rod is made of FRP or metal, and is composed of an anchor rod body and a hollow grouting channel. The anchor rod body is divided into a free section and an anchoring section. The free section is an anchor rod with external threads at both ends, and the anchoring section is provided with a metal sleeve on the outer side. The umbrella-shaped shape memory alloy is arranged on the outer side of the metal sleeve. The metal sleeve is bonded to the anchor rod through the adhesive agent. The anchorage device is composed of a metal anchor disc, a backing plate, a fixing bolt and a grout stopper. The anchor rod is driven into the surrounding rock. The umbrella-shaped shape memory alloy is anchored in the surrounding rock due to the temperature inside the surrounding rock. Grouting is performed through the hollow grouting channel of the anchor rod. The grout stopper is inserted into the grouting channel. The anchor disc and the backing plate are tightly arranged around the anchor rod through the central hole of the anchor disc and the backing plate. The fixing bolt is applied and tightened.

Description

Technical Field

[0001] This invention relates to the field of surrounding rock anchoring technology, applicable to deep engineering and tunnel engineering, specifically to an umbrella-shaped shape memory alloy combined grouting anchor and its construction method. Background Technology

[0002] In the field of deep engineering and tunnel surrounding rock support, anchor bolts are core support components, and their anchoring performance directly affects the long-term stability of the engineering structure. However, anchor bolts are prone to debonding, slippage, or even fracture failure when the surrounding rock undergoes large deformation or dynamic disturbance, making it difficult to meet the reliability and durability requirements of support systems in deep engineering. To address these issues, active anchoring technology based on shape memory alloys (SMA) has emerged in recent years. For example, patent CN222596107U discloses an anchor bolt with memory function, which uses multiple SMA alloy pieces and achieves the expansion and contraction of the alloy through temperature control, using the alloy tail end to lift and compress the hole wall to provide frictional anchoring force; patent CN119824905B discloses an expansion anchor bolt assembly, which adopts a double-layer structure of SMA expansion plate and SMA spring, and achieves coarse and fine adjustment of the expansion shape through temperature control, so that the expansion body presents an optimal trumpet-shaped curve; patent CN222349677U discloses a shape memory alloy prestressed anchor bolt, which uses the axial contraction characteristics of SMA parts to replace jacks to apply prestress.

[0003] Although the above technologies have improved the active anchoring capability of anchor bolts to some extent, the following shortcomings still exist: First, the anchoring mechanism is still mainly based on radial friction or axial prestress. Under deep high ground stress and impact load conditions, the anchoring force is easily affected by the regularity of the borehole and the integrity of the surrounding rock, and the shear and impact resistance performance is limited. Second, alloy triggering methods generally rely on external power supply and temperature control wires, which poses electrical system reliability problems in deep high temperature, high humidity and strong interference environments. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of traditional anchor bolts in terms of sluggish anchoring force and insufficient long-term durability under fractured rock and dynamic load environments. It provides an umbrella-shaped shape memory alloy combined grouting anchor bolt and its construction method. Through the active deformation anchoring of the shape memory alloy and the synergistic strengthening of the grout, the anchor bolt achieves immediate load-bearing capacity and integrated reinforcement of the surrounding rock.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a composite grouting anchor bolt with umbrella-shaped shape memory alloy, comprising a hollow anchor bolt, a metal sleeve fixed on the anchor bolt, a ring of long umbrella-shaped shape memory alloy near the end of the metal sleeve, and a ring of short umbrella-shaped shape memory alloy in the middle of the metal sleeve, with the long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy alternating in the circumferential direction. The ends of the long umbrella-shaped shape memory alloy are designed to be wedge-shaped, and the ends of the short umbrella-shaped shape memory alloy are designed to be barbed. The long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy are triggered by heating with liquid at the temperature of the surrounding rock and / or the phase change temperature inside the anchor bolt.

[0006] The aforementioned long umbrella-shaped shape memory alloy is used to embed into the relatively intact surrounding rock at depth, providing the main anchoring force; the short umbrella-shaped shape memory alloy is used to anchor the fractured area near the borehole wall and fill the gaps between the long umbrella ribs; the long and short umbrella ribs are arranged alternately to form a spatially complementary anchoring skeleton; when uneven deformation occurs in the deep surrounding rock, the synergistic effect of the long and short umbrella ribs can avoid stress concentration and improve the overall stability of the anchoring system.

[0007] As a further technical solution, the length of the long umbrella-shaped shape memory alloy is greater than the length of the metal sleeve; As a further technical solution, the opening angle of the long umbrella-shaped shape memory alloy is 25°-30°.

[0008] As a further technical solution, the length of the short umbrella-shaped shape memory alloy is less than the length of the metal sleeve.

[0009] As a further technical solution, the opening angle of the short umbrella-shaped shape memory alloy is 15°-20°.

[0010] As a further technical solution, the long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy have a one-way memory effect and a phase transition temperature of 50~100℃.

[0011] As a further technical solution, the metal sleeve is bonded together with the anchor rod.

[0012] As a further technical solution, the metal sleeve is connected to the umbrella-shaped shape memory alloy by bolting, with one end of the metal sleeve extending into the drilling direction connected to the long umbrella-shaped shape memory alloy by bolts.

[0013] Secondly, based on the aforementioned umbrella-shaped shape memory alloy composite grouting anchor, the present invention provides a construction method as follows: Based on the internal temperature of the surrounding rock in deep engineering, the shape memory alloy is heated and trained into multiple sets of long umbrella-shaped shape memory alloys and short umbrella-shaped shape memory alloys. The multiple sets of long umbrella-shaped shape memory alloys and short umbrella-shaped shape memory alloys are then connected to the metal sleeve. When the temperature returns to the construction site temperature, the umbrella-shaped shape memory alloys are micro-attached to the outside of the metal sleeve, and then the metal sleeve is fixed to the anchor rod. Drilling holes in the rock mass; Position the anchor bolts; The prefabricated umbrella-shaped shape memory alloy composite grouting anchor is slowly pushed into the borehole to the designed depth, ensuring that the anchoring section of the anchor is fully inserted into the target area of ​​the surrounding rock. The alloy is heated and unfolded into an umbrella shape by the temperature of the surrounding rock or external heating, embedding itself into the rock mass to form an immediate mechanical anchor. The wedge tip is embedded into the micro-fractures of the surrounding rock under the combined action of the umbrella tension and grouting pressure. If creep or impact displacement occurs in the deep surrounding rock, the barbed structure will be embedded deeper as the displacement increases, producing a self-locking effect. Connect the grouting pump to the hollow grouting channel at the tail of the anchor bolt. Pressurize and grout through the hollow channel of the anchor bolt, filling the hole from bottom to top and expelling air; stop grouting when grout overflows from the hole and its concentration is consistent with the injected grout; immediately press the stop plug into the grouting channel opening to prevent grout backflow; Anchor installation.

[0014] As a further technical solution, if the ambient temperature is insufficient, liquid with phase change temperature can be injected through the hollow grouting channel 7 to accelerate the unfolding of the umbrella ribs.

[0015] The above construction method utilizes a temperature-responsive umbrella-shaped structure to quickly embed into the rock mass and form a mechanical interlock. Combined with high-pressure grouting through hollow grouting channels to fill the cracks, it constructs a dual reinforcement system of "active anchoring + chemical bonding," which significantly improves the support efficiency and deformation resistance under complex geological conditions, while reducing resource waste caused by repeated reinforcement.

[0016] The beneficial effects of this invention are as follows: This invention utilizes the temperature response characteristics of umbrella-shaped shape memory alloys. After the anchor is inserted into the borehole, the alloy expands into an umbrella-shaped structure triggered by the surrounding rock temperature or external heating, quickly embedding itself into the rock mass to form a mechanical interlock, achieving immediate load-bearing and effectively coping with dynamic deformation or sudden loads in the surrounding rock. Long umbrella-shaped shape memory alloys are used to embed into relatively intact surrounding rock at depth, providing the main anchoring force; short umbrella-shaped shape memory alloys are used to anchor the fractured area near the borehole wall, filling the gaps between the long umbrella ribs. The alternating arrangement of long and short umbrella ribs forms a spatially complementary anchoring framework. When uneven deformation occurs in the deep surrounding rock, the synergistic effect of the long and short umbrella-shaped shape memory alloys can avoid stress concentration and improve the overall stability of the anchoring system. The radial expansion design of the umbrella-shaped shape memory alloy can cover a larger anchoring range, and the umbrella ribs adapt to the concave and convex surfaces of the borehole wall during embedding, forming multi-point contact anchoring with the surrounding rock. This overcomes the dependence of traditional expandable anchors on regular borehole walls and maintains a uniform anchoring force distribution even in fractured rock masses and fractured strata. Hollow anchor bolts can be further penetrated into the micro-fractures of the rock mass through high-pressure grouting technology to form a root-like reinforcement network. Combined with the mechanical locking of the umbrella-shaped structure, this effectively inhibits grout loss.

[0017] During construction, based on mechanical anchoring, micro-expansion grout is injected under high pressure through hollow grouting channels to fill rock fissures and wrap the umbrella-shaped structure. After curing, it forms a continuous and dense composite anchor body, significantly improving long-term pull-out bearing capacity and fatigue resistance, making it particularly suitable for deep high-stress environments or frequent impact load scenarios. The anchor integrates the hollow grouting channel and the umbrella-shaped anchoring section, achieving integrated "mechanical-chemical" dual anchoring and grouting construction. It eliminates the need for secondary grouting pipe installation or waiting for pre-curing. The active anchoring effect of the umbrella-shaped structure reduces dependence on grout volume, and the anchor body can be made of lightweight, high-strength FRP material, reducing transportation and installation energy consumption. This technology allows for flexible adjustment of the umbrella-shaped structure's deployment temperature, grouting material type, and anchor length, covering diverse engineering needs from tunnel engineering to deep engineering, and from static support to dynamic seismic resistance. Compared to the traditional composite process of anchor and grouting reinforcement, this invention achieves multiple reinforcement effects in a single construction, with significantly reduced subsequent maintenance costs, resulting in significant economic benefits. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a plan view of the anchor rod of the present invention anchored in the borehole; Figure 2 This is a plan view of the anchor bolt of the present invention before it enters the borehole; Figure 3This is a schematic diagram of the structure of a metal sleeve and an umbrella-shaped shape memory alloy. Figure 4 This is a cross-sectional view of the anchor bolt of the present invention; Explanation of reference numerals in the attached drawings: 1. Anchor bolt; 2. Metal anchor plate; 3. Fixing bolt; 4. Umbrella-shaped shape memory alloy; 4-1. Long umbrella-shaped shape memory alloy; 4-2. Short umbrella-shaped shape memory alloy; 4-3. Wedge-shaped tip; 4-4. Barbed structure; 5. Metal sleeve; 6. Adhesive; 7. Hollow grouting channel; 8. Grout stop plug; 9. Gasket. Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] As introduced in the background section, existing anchor designs using shape memory alloys (SMA) are often limited to simple linear deformation, failing to fully utilize the active anchoring potential of SMA, and their long-term fatigue resistance also needs improvement. To address these issues, a composite anchor technology that combines immediate load-bearing capacity, adaptive deformation capability, and long-term reinforcement effect is urgently needed. This invention addresses these technical requirements by proposing an umbrella-shaped shape memory alloy combined grouting anchor and its construction method. The umbrella-shaped radial embedding structure achieves three-dimensional mechanical self-locking, while deep geothermal passive triggering of alloy deployment enhances system reliability. Combined with hollow grouting channels, it achieves root-like grouting reinforcement guided by the umbrella ribs, forming a dual reinforcement system of mechanical anchoring and chemical bonding. This aims to solve the core problems of existing technologies, such as insufficient anchoring force, strong electrical dependence, and grouting-anchoring disconnection under deep and complex geological conditions.

[0022] In a typical embodiment of the present invention, such as Figure 1 As shown, this embodiment provides an umbrella-shaped shape memory alloy combined grouting anchor and its construction method. The purpose of this invention is to address the shortcomings of traditional anchors, such as sluggish anchoring force and insufficient long-term durability in fractured rock masses and dynamic load environments. This invention provides an umbrella-shaped shape memory alloy combined grouting anchor and its construction method, achieving immediate load-bearing capacity and integrated rock reinforcement through the active deformation anchoring of the shape memory alloy and the synergistic strengthening of the grout. This technology utilizes a temperature-responsive umbrella-shaped structure to quickly embed into the rock mass, forming a mechanical interlock. Combined with high-pressure grouting through hollow grouting channels to fill fissures, it constructs a dual reinforcement system of "active anchoring + chemical bonding," significantly improving support efficiency and deformation resistance under complex geological conditions while reducing resource waste caused by repeated reinforcement.

[0023] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, this embodiment describes a grouted anchor bolt made of umbrella-shaped shape memory alloy, which includes an anchor bolt 1, a metal anchor plate 2, a fixing bolt 3, an umbrella-shaped shape memory alloy 4, a metal sleeve 5, and an adhesive 6. The umbrella-shaped shape memory alloy 4 includes a long umbrella-shaped shape memory alloy 41 and a short umbrella-shaped shape memory alloy 42; A metal sleeve 5 is fixed to the anchor bolt 1. A ring of long umbrella-shaped shape memory alloy 41 is arranged near the end of the metal sleeve 5, and a ring of short umbrella-shaped shape memory alloy 42 is arranged in the middle of the metal sleeve 5. The long umbrella-shaped shape memory alloy 41 and the short umbrella-shaped shape memory alloy 42 are alternately arranged in the circumferential direction. The ends of the long umbrella-shaped shape memory alloy 41 are wedge-shaped, and the ends of the short umbrella-shaped shape memory alloy 42 are barbed. The long umbrella-shaped shape memory alloy 41 and the short umbrella-shaped shape memory alloy 42 are triggered by heating the surrounding rock temperature and / or the phase change temperature liquid inside the anchor bolt. The temperature response characteristics of Gold 4 allow the alloy to expand into an umbrella-shaped structure after the anchor is inserted into the borehole, triggered by the surrounding rock temperature or external heating. This structure quickly embeds into the rock mass, forming a mechanical interlock and enabling immediate load-bearing, effectively responding to dynamic deformation or sudden loads in the surrounding rock. Long umbrella-shaped shape memory alloy 41 is used to embed into relatively intact surrounding rock at depth, providing the main anchoring force. Short umbrella-shaped shape memory alloy 42 is used to anchor the fractured area near the borehole wall, filling the gaps between the long umbrella ribs. The alternating arrangement of long and short umbrella ribs forms a spatially complementary anchoring framework. When uneven deformation occurs in the deep surrounding rock, the synergistic effect of the long and short umbrella ribs can avoid stress concentration and improve the overall stability of the anchoring system. The radial expansion design of the umbrella-shaped shape memory alloy can cover a larger anchoring range, and the umbrella ribs adapt to the concave and convex surfaces of the borehole wall during embedding, forming multi-point contact anchoring with the surrounding rock. This overcomes the dependence of traditional expandable anchors on regular borehole walls and maintains a uniform anchoring force distribution even in fractured rock masses and fractured strata.

[0024] Specifically, the anchor rod 1 can be made of FRP or metal. The anchor rod consists of the anchor rod body and the reserved hollow grouting channel 7. The anchor rod body is divided into a free section A and an anchoring section B. The free section A is connected to the anchorage. The anchoring section B is mainly for anchoring. Its outer side has a metal sleeve 5 and an umbrella-shaped shape memory alloy. The outer side of the metal sleeve 5 has an umbrella-shaped shape memory alloy 4. The inner side of the metal sleeve 5 is bonded to the anchor rod 1 with adhesive 6. The anchorage consists of a metal anchor plate 2, a pad 9, a fixing bolt 3, and a grout stop plug 8. The anchor rod 1 is driven into the surrounding rock. The umbrella-shaped shape memory alloy 4 is anchored in the surrounding rock due to the temperature recovery training shape inside the surrounding rock. Grouting is performed using the hollow grouting channel 7 of the anchor rod 1. The grout stop plug 8 is inserted into the grouting channel opening. The central circular hole of the metal anchor plate 2 and the pad 9 passes through the anchor rod 1 and is tightly attached to the surrounding rock. The fixing bolt 3 is applied and tightened.

[0025] like Figure 1 , Figure 2 As shown, the outer side of the anchor rod 1 may be threaded or unthreaded, and a hollow grouting channel 7 is reserved in the middle of the anchor rod 1.

[0026] like Figure 1 , Figure 2As shown, the anchor bolt 1 is made of metal or FRP material, wherein the metal is at least one of iron, aluminum, magnesium, titanium, nickel or its alloy or metal matrix composite material, and the FRP is at least one of glass fiber, carbon fiber, basalt fiber, aramid fiber or the like.

[0027] like Figure 3 As shown, the metal sleeve 5 is open at both ends. Four mutually perpendicular bolt connection holes are pre-drilled at one end of the metal sleeve 5 in the direction of drilling. The outer diameter of the metal sleeve 5 is 8-12mm larger than the outer diameter of the anchor rod 1. The outer side of the metal sleeve 5 is coated with an anti-corrosion coating.

[0028] A spiral guide groove with a depth of 1 is opened on the outer side of the metal sleeve 5. 2mm, groove width 3 5mm, helix angle 30°-45°. This helical groove has a dual function: (1) Grouting guidance: During grouting, the grout that emerges from the end of the anchor rod can be evenly distributed along the spiral groove to the gap between each umbrella bone, avoiding grouting dead corners and forming a continuous and dense grouting envelope; (2) Stress buffering: When rock bursts or rockbursts occur in the deep surrounding rock, the spiral structure can withstand 5% stress. With 10% elastic deformation, it absorbs impact energy, protects the anchor rod from instantaneous damage, and achieves a synergistic effect of "pressure relief and anchoring".

[0029] like Figure 3 As shown, the umbrella-shaped shape memory alloy 4 includes a long umbrella-shaped shape memory alloy 41 and a short umbrella-shaped shape memory alloy 42. The metal sleeve 5 is connected to the umbrella-shaped shape memory alloy 41 by bolting. The end of the metal sleeve 5 that extends into the drilling direction is connected to the umbrella-shaped shape memory alloy by bolts.

[0030] The ends of the long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 42 are designed as wedge-shaped tips or barbed structures, wherein the end of the long umbrella-shaped shape memory alloy 41 is designed as a wedge-shaped structure 43 and the end of the short umbrella-shaped shape memory alloy 42 is designed as a barbed structure 44. When temperature triggers deployment, the wedge-shaped tip embeds into the micro-fractures of the surrounding rock under the combined action of the umbrella rib tension and grouting pressure. If creep or impact displacement occurs in the deep surrounding rock, the hook structure will embed deeper with increasing displacement, generating a self-locking effect and significantly improving the anchor's impact and pull-out resistance. The umbrella rib embedding depth can reach 20 mm. 50mm, forming a reliable mechanical locking layer.

[0031] The umbrella-shaped shape memory alloy is designed with a multi-level structure of alternating long and short ribs: Long umbrella-shaped shape memory alloy 41 (4 pieces): Length L + 20mmL (L is the length of the metal sleeve), opening angle 25° 30°, used for embedding in deep, relatively intact surrounding rock, providing the main anchoring force; short umbrella-shaped shape memory alloy 42 (4 pieces): length L 10mmL, opening angle 15° A 20° angle is used to anchor the fractured zone near the borehole wall, filling the gaps between the long umbrella-shaped ribs. The alternating arrangement of long and short umbrella-shaped ribs forms a spatially complementary anchoring framework. When uneven deformation occurs in the deep surrounding rock, the synergistic effect of the long and short umbrella-shaped ribs can prevent stress concentration and improve the overall stability of the anchoring system.

[0032] like Figure 1 , Figure 2 , Figure 4 As shown. The long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 are pre-trained, with a total of 8 pieces and a thickness of 2mm~4mm. The long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 are each prepared from one of Ni-Ti-based, Cu-based, and Fe-based materials. The long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 have a one-way memory effect and a phase transition temperature of 50~100℃.

[0033] like Figure 1 , Figure 2 , Figure 3 As shown. The triggering methods of the long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 can be divided into two types: natural temperature triggering: relying on the ambient temperature of the surrounding rock (such as geothermal or deep rock mass temperature), after standing for 10-15 minutes, the alloy umbrella ribs are heated and unfold, embedding into the rock mass and interlocking with the surrounding rock. Active heating triggering: if the ambient temperature is insufficient, liquid at the phase change temperature is injected through the hollow grouting channel 7 to accelerate the unfolding of the umbrella ribs.

[0034] like Figure 3 As shown. Adhesive 6 is at least one of epoxy structural adhesive, acrylic structural adhesive, polyurethane structural adhesive, and anaerobic adhesive.

[0035] This embodiment discloses a construction method for an umbrella-shaped shape memory alloy composite grouting anchor, the steps of which are as follows: (1) Anchor bolts and metal sleeves: According to the deep engineering design requirements, determine the number of anchor bolts (1), the overall length and the length of anchoring section B and free section A, the number of metal sleeves 5 and the number of the matching long umbrella-shaped shape memory alloy 4-1 and short umbrella-shaped shape memory alloy 4-2.

[0036] (2) Training and assembly of umbrella-shaped shape memory alloy and anchor bolt: Apply adhesive 6 to the inside of the metal sleeve 5, press the metal sleeve 5 and anchor bolt 1 anchoring section B together and let it stand until the adhesive 6 cures. Determine the actual temperature range of the anchoring area based on the geothermal survey data of deep engineering. Heat the SMA alloy in the laboratory to train its phase transformation temperature slightly lower than (5 ℃). (10℃) Lower limit of measured ground temperature. For example, if the measured ground temperature is 55℃... The phase transformation temperature of the training alloy is 50℃. After training, the alloy is attached to the metal sleeve at room temperature to ensure that it remains closed during transportation and installation. The long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 are connected to the metal sleeve 5 with bolts. When the temperature returns to the construction site temperature, the long umbrella-shaped shape memory alloy 4-1 and the short umbrella-shaped shape memory alloy 4-2 are slightly attached to the outside of the metal sleeve 5. The assembled metal sleeve 5 is then installed in the anchoring section of the anchor rod 1 according to the deep engineering design requirements.

[0037] (3) Anchor positioning and drilling: According to the deep engineering design requirements, the surrounding rock support area is divided and positioned using measuring instruments. Drilling is carried out at the positioned location. The diameter of the drilling hole is 6mm-12mm larger than the outer diameter of the anchor. After drilling, the hole is cleaned.

[0038] (4) Adaptive anchoring construction: 4.1 Slowly push the prefabricated long umbrella-shaped shape memory alloy 4-1 and short umbrella-shaped shape memory alloy 4-2 combined grouting anchor 1 from step (2) into the borehole to the designed depth; 4.2 Static Geothermal Trigger: Static for 10 minutes In 15 minutes, the SMA umbrella ribs gradually unfolded by utilizing the heat of the surrounding deep rock, embedding into the rock mass to form an initial mechanical anchor. 4.3 Grouting-assisted deployment: If the measured ground temperature is lower than expected or construction needs to be accelerated, 60 mm of grout can be injected through the hollow grouting channel 7. Hot water at 80℃ or phase change triggering fluid helps the umbrella ribs to fully unfold; 4.4 High-pressure grouting anchoring: After the umbrella ribs are fully deployed, immediately connect to the hollow grouting channel 7 at the tail of anchor rod 1 for 2... High-pressure pulsed grouting at 3MPa is used to further press the tips of the grout ribs into the rock mass fissures using the grouting pressure. Simultaneously, the grout permeates along the gaps between the ribs, forming a root-like reinforcement network. Grouting is stopped when grout overflows from the borehole and its concentration matches that of the injected grout. A grout stop plug is immediately inserted into the grouting channel to prevent grout backflow.

[0039] (5) Anchor installation: Pass the metal anchor plate 2 and the pad 9 through the exposed end of the free section of the anchor rod 1, close to the surrounding rock surface, and adjust to a horizontal state. Tighten the fixing bolt 3 with a torque wrench.

[0040] (6) Construct the next borehole anchor 1 according to the steps of (2), (3), (4), (5), (6) until all surrounding rock support construction is completed.

[0041] The high-pressure grouting via anchor bolts described above can penetrate into micro-fractures in the rock mass, forming a root-like reinforcement network. Combined with the mechanical locking of the umbrella-shaped rib structure, this effectively inhibits grout loss. Based on mechanical anchoring, micro-expansion grout is injected under high pressure through hollow grouting channels to fill rock fissures and encapsulate the umbrella-shaped rib structure. After solidification, it forms a continuous and dense composite anchor body, significantly improving long-term pull-out bearing capacity and fatigue resistance, making it particularly suitable for deep, high-stress environments or frequent impact load scenarios. The anchor bolts integrate hollow grouting channels and umbrella-shaped rib anchoring sections, achieving integrated "mechanical-chemical" dual anchoring and grouting construction. This eliminates the need for secondary grouting pipe installation or pre-curing waiting. The active anchoring effect of the umbrella-shaped rib structure reduces dependence on grout volume, and the anchor bolt body can be made of lightweight, high-strength FRP material, reducing transportation and installation energy consumption. This technology allows for flexible adjustment of the umbrella-shaped rib deployment temperature, grouting material type, and anchor bolt length, covering diverse engineering needs from tunnel engineering to deep engineering, and from static support to dynamic seismic resistance. Compared to the traditional composite process of anchor bolts and grouting reinforcement, this invention can achieve multiple reinforcement effects with a single construction, and the subsequent maintenance costs are greatly reduced, resulting in significant economic benefits.

[0042] Finally, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A shape memory alloy composite grouting anchor bolt with umbrella-shaped ribs, comprising a hollow anchor bolt, characterized in that, A metal sleeve is fixed to the anchor bolt. A ring of long umbrella-shaped shape memory alloy is set near the end of the metal sleeve, and a ring of short umbrella-shaped shape memory alloy is set in the middle of the metal sleeve. The long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy are alternately arranged in the circumferential direction. The end of the long umbrella-shaped shape memory alloy is designed to be wedge-shaped, and the end of the short umbrella-shaped shape memory alloy is designed to be barbed. The long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy are triggered by heating with liquid at the temperature of the surrounding rock and / or the phase change temperature inside the anchor bolt.

2. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The length of the long umbrella-shaped shape memory alloy is greater than the length of the metal sleeve.

3. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The opening angle of the long umbrella-shaped shape memory alloy is 25°-30°.

4. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The length of the short umbrella-shaped shape memory alloy is less than the length of the metal sleeve.

5. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The opening angle of the short umbrella-shaped shape memory alloy is 15°-20°.

6. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The long umbrella-shaped shape memory alloy and the short umbrella-shaped shape memory alloy exhibit a one-way shape memory effect with a phase transition temperature of 50~100℃.

7. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The metal sleeve is bonded together with the anchor rod.

8. The umbrella-shaped shape memory alloy composite grouting anchor bolt as described in claim 1, characterized in that, The metal sleeve is connected to the umbrella-shaped shape memory alloy by bolting, with one end of the metal sleeve extending into the drilling direction connected to the long umbrella-shaped shape memory alloy by bolts.

9. A construction method for an umbrella-shaped shape memory alloy composite grouting anchor bolt according to any one of claims 1-8, characterized in that, as follows: Based on the internal temperature of the surrounding rock in deep engineering, the shape memory alloy is heated and trained into multiple sets of long umbrella-shaped shape memory alloys and short umbrella-shaped shape memory alloys. The multiple sets of long umbrella-shaped shape memory alloys and short umbrella-shaped shape memory alloys are then connected to the metal sleeve. When the temperature returns to the construction site temperature, the umbrella-shaped shape memory alloys are micro-attached to the outside of the metal sleeve, and then the metal sleeve is fixed to the anchor rod. Drilling holes in the rock mass; Position the anchor bolts; The prefabricated umbrella-shaped shape memory alloy composite grouting anchor is slowly pushed into the borehole to the designed depth, ensuring that the anchoring section of the anchor is fully inserted into the target area of ​​the surrounding rock. The alloy is heated and unfolded into an umbrella shape by the temperature of the surrounding rock or external heating, embedding itself into the rock mass to form an immediate mechanical anchor. The wedge tip is embedded into the micro-fractures of the surrounding rock under the combined action of the umbrella tension and grouting pressure. If creep or impact displacement occurs in the deep surrounding rock, the barbed structure will be embedded deeper as the displacement increases, producing a self-locking effect. Connect the grouting pump to the hollow grouting channel at the tail of the anchor bolt; pressurize and grout from the hollow channel of the anchor bolt, filling the hole from bottom to top and expelling air; stop grouting when grout overflows from the hole and the concentration is consistent with the injected grout; immediately press the stop plug into the grouting channel opening to prevent grout backflow; Anchors are installed at the ends of the anchor bolts.

10. The construction method of the umbrella-shaped shape memory alloy combined grouting anchor bolt as described in claim 9, characterized in that, If the ambient temperature is insufficient, inject liquid at the phase change temperature through the hollow grouting channel to accelerate the unfolding of the umbrella ribs.

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