A light-micro basalt fiber tendon prestressed anchor cable and a method of using the same

Abstract

The present application relates to a kind of light-minity basalt fiber tendon prestressed anchor cable and its use method, belong to geotechnical engineering technical field.Prestressed anchor cable includes anchor cable stem, anchorage body and drawing mechanism, anchor cable stem is bounded by multiple bundles of basalt fiber tendon, anchorage body is spaced distribution in the tail end and middle part of anchor cable stem, anchorage body is the hot melt adhesive layer of anchor cable stem, and hot melt adhesive layer is embedded with heating wire;Drawing mechanism includes drawing nut, drawing screw, rubber plug and limit block, drawing screw and rubber plug are worn on anchor cable stem, drawing nut is threadedly connected on the outside of drawing screw, rubber plug is conical structure, its small diameter end is loaded into the taper hole of drawing screw, and rubber plug taper surface and taper hole form taper surface cooperation, limit block is pressed in the large diameter end of rubber plug, and extrude rubber plug, so that the inner hole of rubber plug clamps anchor cable stem.The prestressed anchor cable can be used to solve the light-mild reinforcement problem of local fissure of important rock mass such as grotto temple, statue etc.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering technology, specifically relating to a lightweight micro basalt fiber reinforced prestressed anchor cable and its application method. Background Technology

[0002] Prestressed anchor cables are widely used in geotechnical engineering reinforcement and protection, covering infrastructure construction in water conservancy, transportation, building, and energy sectors. Prestressed anchor cables actively apply prestress, effectively controlling soil and rock deformation and improving their stress state. This technology features "active support and flexible support," effectively reinforcing soil and rock while protecting the environment. Simultaneously, prestressed anchor cables optimize structural internal forces, saving on project costs, and their application significantly enhances the stability of landslides, high slopes, and other engineering projects.

[0003] To improve the reinforcement effect of soil and rock masses, many domestic and foreign institutions have developed anchor cable reinforcement technologies adapted to different soil and rock properties. For example, invention patent application number 201910914530X discloses a basalt fiber prestressed anchor cable system and its anchoring method. This device has a serrated tail-end anchor in the anchoring section that works with the basalt fiber anchor cable to increase the mechanical interlocking force between the anchoring grout and the anchor cable. Invention patent application number 2023105588589 discloses a hybrid prestressed anchor cable of basalt reinforcement and steel strands and its application method. This anchor cable body consists of multiple steel strands and... Composed of multiple basalt reinforcements, it can fully utilize the shear resistance of steel strands and the tensile resistance of basalt reinforcements, while meeting the tensile and shear strength requirements of the project. The invention patent with application number 2023105572650 discloses a prestressed basalt fiber anchor cable micro anti-slide pile and its construction method. Applying prestress to the anti-slide pile keeps it under compression and prevents cracking, thus ensuring the bearing capacity of the micro anti-slide pile during long-term use.

[0004] It should be noted that the aforementioned basalt fiber-reinforced anchor cables are all designed for large-scale geotechnical engineering reinforcement scenarios. Their anchor cable dimensions, anchoring structures, and prestressing methods are all geared towards adapting to large-scale geotechnical reinforcement. These cables are generally large in scale and complex in structure, making them unsuitable for the miniaturized, lightweight, and precise construction requirements of localized micro-reinforcement of important stone cultural relics such as grottoes and statues. Furthermore, the reinforcement of stone cultural relics must fully consider the special requirements of cultural relic protection; the reinforcement process and materials must not cause damage to the relics themselves. However, existing anchor cable technologies may disturb or damage the relics during drilling, anchoring, and prestressing. Therefore, developing a basalt fiber-reinforced anchor cable capable of localized light-to-micro-reinforcement of important rock masses such as grottoes and statues without damaging the relics is of significant value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a lightweight micro-basalt fiber-reinforced prestressed anchor cable and its application method, aiming to explore solutions for lightweight micro-reinforcement of local cracks in important rock masses such as grottoes and statues.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: a lightweight micro basalt fiber reinforced prestressed anchor cable, comprising an anchor cable body, an anchor body, and a pull-out mechanism. The anchor cable body is composed of multiple bundles of basalt fiber reinforced tendons bound together. The anchor body is spaced apart at the tail end and middle of the anchor cable body. The anchor body is a hot melt adhesive layer that wraps around the anchor cable body, and an electric heating wire is embedded in the hot melt adhesive layer. The pull-out mechanism includes a pull-out nut, a pull-out screw, a rubber plug, and a limiting block. The pull-out screw and the rubber plug are sleeved on the head of the anchor cable body. The pull-out nut is threaded to the outside of the pull-out screw. The rubber plug is a hollow conical structure, with its small-diameter end inserted into the conical hole in the pull-out screw, and the conical surface on the outside of the rubber plug forms a conical surface fit with the conical hole. The limiting block presses against the large-diameter end of the rubber plug and squeezes the rubber plug by being fixedly connected to the pull-out screw, so that the inner hole of the rubber plug clamps the anchor cable body. After the anchor rod is inserted into the borehole of the rock mass, the innermost anchor body in the borehole is heated first to achieve pre-fixation between the anchor rod and the borehole. After the anchor rod is pulled out by the pulling mechanism, the remaining anchor bodies are heated to achieve prestress loading.

[0007] Furthermore, the heating wire is laid along the length of the anchor rod and extends out of the drill hole to connect with the corresponding wire.

[0008] Furthermore, the position and length of the anchor body in the middle of the anchor rod should be selected to ensure that after the anchor rod is installed in the borehole, the entire anchor body in the middle of the anchor rod is located inside the borehole.

[0009] Furthermore, an anchor body is provided at both the tail end and the middle of the anchor cable rod.

[0010] Furthermore, the diameter of the anchor rod is 1~3mm.

[0011] Furthermore, the rubber plug and the anchor rod are in a loose fit when the rubber plug is in the initial state.

[0012] Furthermore, when the limiting block contacts the end face of the pulling screw, the space enclosed by the limiting block and the pulling screw is smaller than the volume of the rubber plug in its initial state.

[0013] Furthermore, the limiting block is fixedly connected to the pull screw by connecting bolts.

[0014] Furthermore, a pressure sensor is provided at the front end of the pull nut.

[0015] This invention also proposes a method for using the aforementioned lightweight micro-basalt fiber-reinforced prestressed anchor cable, which is used to reinforce rock formations used for cultural relics, and includes the following steps: The first step is to place the anchor rod with hot melt adhesive applied and heating wires embedded in the hot melt adhesive layer into the pre-drilled hole in the rock mass, ensuring that the hot melt adhesive layer on the anchor rod is completely inside the hole. The second step is to heat the heating wire inside the hot melt adhesive layer at the tail end of the anchor cable rod, so that the hot melt adhesive melts and adheres to the borehole wall, and then stop heating; The third step is to install the aforementioned pulling mechanism, and to use the limiting block to squeeze the rubber plug and clamp the anchor cable rod body; Fourth step: Rotate the pull-out nut to force the pull-out screw to move away from the rock mass, thereby stretching the anchor cable rod out of the hole until the pull-out load on the anchor cable rod reaches the preset target, then stop rotating the pull-out nut; The fifth step is to heat the heating wires in the hot melt adhesive layer on the anchor rod except for the tail end. The heating is stopped after the hot melt adhesive has completely melted and bonded to the inner wall of the borehole. The sixth step is to remove the aforementioned pulling mechanism and cut off any remaining anchor rods outside the hole to achieve non-destructive, light-to-micro reinforcement of the stone cultural relic rock mass.

[0016] The beneficial effects of this invention are as follows: This invention aims to explore solutions to the problem of light-to-micro reinforcement of localized cracks in important rock masses such as grottoes and statues. The anchor rod is made of lightweight, corrosion-resistant basalt fiber reinforcement. The tail and middle of the anchor rod are equipped with an anchor body composed of hot-melt adhesive. The heating and re-solidification of the hot-melt adhesive achieves bonding between the anchor rod and the borehole wall. Controlling the rotation of the pull-out nut causes the rubber plug to stretch the anchor rod, achieving pre-tightening of the anchor. The pull-out load of the anchor rod can be controlled by adjusting the rotation angle of the pull-out nut. Furthermore, the rubber plug used in this invention has a flexible fit with the anchor rod, preventing basalt fiber splitting due to rigid compression. This invention's anchor structure is simple and easy to use, contributing to the development of important rock mass reinforcement technology. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the lightweight-micro basalt fiber reinforced prestressed anchor cable described in this invention; The markings in the diagram are: 1. Rock mass, 2. Drill hole, 3. Anchor cable rod, 4. Anchor body, 4.1. Hot melt adhesive layer, 4.2. First heating wire, 4.3. Second heating wire, 5. Pulling mechanism, 5.1. Pulling nut, 5.2. Pulling screw, 5.3. Rubber plug, 5.4. Limiting block, 5.5. Connecting bolt, 6. Pressure sensor, 7. First wire, 8. Second wire. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments, but this should not be construed as limiting the invention in any way.

[0019] Example 1

[0020] like Figure 1 As shown, the lightweight micro basalt fiber reinforced prestressed anchor cable of the present invention includes an anchor cable rod 3, an anchor body 4, and a pull-out mechanism 5.

[0021] The anchor rod 3 is composed of multiple bundles of basalt fiber reinforcements, with a diameter of 1-3 mm. Anchor bodies 4 are provided at the tail and middle of the anchor rod 3. The anchor body 4 is a hot melt adhesive layer 4.1 that wraps around the anchor rod 3, and heating wires are embedded within the hot melt adhesive layer 4.1. The heating wire in the hot melt adhesive layer 4.1 at the tail of the anchor rod 3 is a first heating wire 4.2, and the heating wire in the hot melt adhesive layer 4.1 in the middle of the anchor rod 3 is a second heating wire 4.3. After the anchor rod 3 is inserted into the borehole 2 of the rock mass 1, the two hot melt adhesive layers 4.1 at the tail and middle of the anchor rod 3 are completely located inside the borehole 2. The first heating wire 4.2 and the second heating wire 4.3 are laid along the length of the anchor rod 3 and led out of the borehole. They are connected to a heating power source through the first wire 7 and the second wire 8, respectively. The first heating wire 4.2 and the second heating wire 4.3 are used to heat and melt the corresponding hot melt adhesive layers 4.1. By utilizing the characteristic of the hot melt adhesive to cool and solidify rapidly after melting, the anchor rod 3 and the borehole wall of the borehole 2 are fully wetted and bonded, and the pre-tightened anchor rod 3 is fixed inside the borehole 2.

[0022] The pulling mechanism 5 is located at the head of the anchor cable rod 3 extending out of the drill hole 2, and is used to pull and pre-tighten the anchor cable rod 3. It includes a threaded pulling nut 5.1, a pulling screw 5.2, a rubber plug 5.3, a limiting block 5.4, and a connecting bolt 5.5.

[0023] The pull screw 5.2 has a central hole that passes through the anchor cable body 3. The diameter of the central hole is larger than the diameter of the anchor cable body 3. The pull nut 5.1 is threaded onto the outside of the pull screw 5.2 and can compress the rock mass 1 around the borehole 2 during the screwing process. The central hole of the pull screw 5.2 is divided into a conical section and a cylindrical section, with the cylindrical section adjacent to the rock mass. The rubber plug 5.3 has a conical structure and a through hole in the center that passes through the anchor cable body 3. When the rubber plug 5.3 is in its initial uncompressed state, there is a loose fit between the rubber plug 5.3 and the anchor cable body 3, allowing the anchor cable body 3 to pass smoothly through the rubber plug 5.3 and adjust its position on the anchor cable body 3. The small-diameter end of the rubber plug 5.3 is inserted into the conical section of the pull screw 5.2. The limiting block 5.4 presses against the large-diameter end of the rubber plug 5.3, and the limiting block 5.4 and the pulling screw 5.2 are fastened together by the connecting bolt 5.5 to compress the rubber plug 5.3, so that the conical surface of the rubber plug 5.3 fits tightly with the conical hole section of the pulling screw 5.2. At the same time, the deformation of the rubber plug 5.3 causes the through hole in its center to clamp the anchor cable rod 3. The greater the squeezing force of the limiting block 5.4 on the rubber plug 5.3, the greater the clamping force of the rubber plug 5.3 on the anchor cable rod 3.

[0024] By screwing the pull nut 5.1 toward the rock mass 1, the pull nut 5.1 squeezes the rock mass 1. Under the action of the thread, the pull screw 5.2 moves linearly away from the rock mass 1, driving the rubber plug 5.3 to move. Thus, the rubber plug 5.3 pulls the anchor cable rod 3 to the outside of the borehole 2, pre-tightening the anchor cable rod 3.

[0025] In other embodiments, the entire central hole of the pull screw 5.2 is a tapered hole.

[0026] In practical applications, the number of anchor bodies 4 on the anchor rod 3 can be increased according to the actual situation. For example, two or more anchor bodies 4 can be set in the middle of the anchor rod 3, with each anchor body 4 corresponding to a heating wire. Alternatively, instead of increasing the number of anchor bodies 4, the length of each anchor body 4 can be increased, thereby increasing the contact area between the hot melt adhesive and the inner wall of the borehole 2, and increasing the fixing strength between the anchor rod 3 and the borehole 2.

[0027] When the front end of the limiting block 5.4 contacts the end face of the pulling screw 5.2, the space enclosed by the limiting block 5.4 and the pulling screw 5.2 is smaller than the volume of the rubber plug 5.3 in its initial uncompressed state. This ensures that after the rubber plug 5.3 is inserted into the pulling screw 5.2, the limiting block 5.4 can press the rubber plug 5.3 tightly before contacting the pulling screw 5.2. This avoids the pressure on the rubber plug 5.3 being too small to deform and clamp the anchor cable, and thus avoids relative sliding between the rubber plug 5.3 and the anchor cable body 3 during the pre-tightening process, which would make it difficult to achieve the preset pre-tightening degree.

[0028] In order to obtain accurate pull-out load during the pre-tightening process, a pressure sensor 6 is also provided between the pull-out nut 5.1 and the rock mass 1. During the screwing-in of the pull-out nut 5.1, the pressure sensor 6 is acted upon to realize real-time monitoring of the pull-out load of the anchor cable rod 3.

[0029] Using this device, prestressing can be applied to basalt fiber reinforced anchor rods. After removing the pull-out mechanism, trimming the anchor head can complete non-destructive light to micro-reinforcement of important rock masses.

[0030] Example 2

[0031] This embodiment describes the application method of the lightweight-micro basalt fiber reinforced prestressed anchor cable described in Embodiment 1. The aforementioned lightweight-micro basalt fiber reinforced prestressed anchor cable can be used to reinforce important rock formations of stone cultural relics such as grottoes and statues. The method includes the following steps: The first step is to drill holes 2 in the rock mass 1 that needs to be reinforced, and apply hot melt adhesive to the tail end and middle of the anchor rod 3 to form a hot melt adhesive layer 4.1 that wraps the anchor rod 3 and the heating wire. Then, the anchor rod 3 is placed into the drill hole 2, ensuring that the hot melt adhesive layer 4.1 in the middle of the anchor rod 3 is completely inside the drill hole. The first heating wire 4.2 and the second heating wire 4.3 extend out of the drill hole 2 and are connected to the first conductor 7 and the second conductor 8, respectively. The second step is to heat the first heating wire 4.2 through the first wire 7, so that the corresponding hot melt adhesive layer 4.1 is completely melted and fully bonded to the hole wall of the borehole 2. Then, the heating is stopped, and after the hot melt adhesive cools and solidifies, the tail end of the anchor rod 3 is fixed in the borehole 2 to achieve the pre-fixation of the anchor rod 3 in the borehole 2, so as to facilitate the subsequent pre-tightening. The third step involves sequentially placing the pressure sensor 6, the pull nut 5.1, and the pull screw 5.2 onto the end of the anchor cable body 3 outside the borehole 2. The pull nut 5.1 is then rotated so that its end contacts the surface of the rock mass 1 surrounding the borehole 2. Next, a rubber plug 5.3 is installed on the anchor cable body 3, and the rubber plug 5.3 is pushed into the center hole of the pull screw 5.2. The outer conical surface of the rubber plug 5.3 contacts the conical surface of the center hole. A limiting block 5.4 is installed using the connecting bolt 5.5 to compress the rubber plug 5.3, ensuring that the conical surface of the rubber plug 5.3 tightly fits the conical surface of the center hole of the pull screw 5.2. This clamps the anchor cable body 3 with the rubber plug 5.3, thus completing the assembly of the pull mechanism 5. Fourth step, screw the pull nut 5.1 toward the rock mass 1, push the pull screw 5.2 away from the rock mass 1, tighten it and drive the rubber plug 5.3 to move, thereby stretching the anchor cable rod 3 out of the hole. During this process, the magnitude of the pull load can be monitored in real time by the pressure sensor 6. Stop rotating the pull nut 5.1 when the pull load reaches the specified pressure. Fifth step: Maintain the pre-tightening of the anchor rod body 3 by the pulling mechanism 5 in the previous step, heat the second heating wire 4.3 through the second wire 8 to melt the corresponding hot melt adhesive layer 4.1 and fully bond it to the hole wall of the borehole 2. Then stop heating. After the hot melt adhesive cools and solidifies, fix the middle part of the anchor rod body 3 in the borehole 2 to achieve secondary fixation of the anchor rod body 3 in the borehole 2. At this time, the anchor rod body 3 can be reliably fixed in the borehole 2 through pre-fixation and secondary fixation. The sixth step involves sequentially removing the limiting block 5.4, rubber plug 5.3, pull screw 5.2, pull nut 5.1, and pressure sensor 6, and cutting off the remaining anchor rod 3 outside the hole, thus achieving non-destructive light to micro-reinforcement of the important rock mass of the stone cultural relic.

[0032] In the fourth step above, when the pull screw 5.2 moves, it tends to continue to squeeze the rubber plug 5.3, which can maintain the clamping force of the rubber plug 5.3 on the anchor cable rod 3, and avoid relative displacement between the anchor cable rod 3 and the rubber plug 5.3 due to insufficient clamping force during the pre-tightening process, thereby ensuring the smooth pre-tightening of the anchor cable rod 3.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the pending claims.

Claims

1. A lightweight micro-basalt fiber reinforced prestressed anchor cable, comprising an anchor cable rod (3), an anchor body (4), and a pull-out mechanism (5), wherein the anchor cable rod (3) is composed of multiple bundles of basalt fiber reinforcement, characterized in that, The anchor body (4) is distributed at intervals at the tail end and middle of the anchor rod (3). The anchor body (4) is a hot melt adhesive layer (4.1) that wraps the anchor rod (3), and an electric heating wire is embedded in the hot melt adhesive layer (4.1). The pulling mechanism (5) includes a pulling nut (5.1), a pulling screw (5.2), a rubber plug (5.3), and a limiting block (5.4). The pulling screw (5.2) and the rubber plug (5.3) are sleeved on the head of the anchor rod (3). 1) The threaded connection is on the outside of the pull screw (5.2). The rubber plug (5.3) is a hollow conical structure. Its small diameter end is inserted into the conical hole in the pull screw (5.2). The conical surface on the outside of the rubber plug (5.3) and the conical hole form a conical surface fit. The limiting block (5.4) presses against the large diameter end of the rubber plug (5.3) and squeezes the rubber plug (5.3) by being fixedly connected to the pull screw (5.2) so that the inner hole of the rubber plug (5.3) clamps the anchor rod body (3). After the anchor rod (3) is inserted into the borehole (2) of the rock mass (1), the innermost anchor body (4) in the borehole (2) is heated first to achieve pre-fixation of the anchor rod (3) and the borehole (2). After the anchor rod (3) is pulled out by the pulling mechanism (5), the remaining anchor bodies (4) are heated to achieve prestress loading.

2. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, The heating wire is laid along the length of the anchor rod (3) and extends out of the drill hole (2) to be connected to the corresponding wire.

3. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, The position and length of the anchor body (4) in the middle of the anchor rod (3) should be selected to ensure that after the anchor rod (3) is installed into the borehole (2), the anchor body (4) in the middle of the anchor rod (3) is completely located inside the borehole (2).

4. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, An anchor body (4) is provided at both the tail end and the middle of the anchor rod (3).

5. The lightweight micro-basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, The diameter of the anchor rod (3) is 1~3mm.

6. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, When the rubber plug (5.3) is in its initial state, it is loosely fitted with the anchor rod (3).

7. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, When the limiting block (5.4) contacts the end face of the pulling screw (5.2), the space enclosed by the limiting block (5.4) and the pulling screw (5.2) is smaller than the volume of the rubber plug (5.3) in its initial state.

8. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, The limiting block (5.4) is fixedly connected to the pulling screw (5.2) by the connecting bolt (5.5).

9. The lightweight-micro basalt fiber reinforced prestressed anchor cable according to claim 1, characterized in that, A pressure sensor (6) is provided at the front end of the pull-out nut (5.1).

10. The method of using the lightweight-micro basalt fiber reinforced prestressed anchor cable as described in any one of claims 1-9, characterized in that, This method is used to reinforce rock formations of stone cultural relics and includes the following steps: The first step is to place the anchor rod (3) with hot melt adhesive applied and electric heating wire embedded in the hot melt adhesive layer (4.1) into the pre-set borehole (2) on the rock mass (1), and ensure that the hot melt adhesive layer (4.1) on the anchor rod (3) is completely located in the borehole (2); The second step is to heat the heating wire in the hot melt adhesive layer (4.1) at the tail end of the anchor rod (3) so that the hot melt adhesive melts and adheres to the borehole wall (2), and then stop heating. The third step is to install the aforementioned pulling mechanism (5), and to squeeze the rubber plug (5.3) by the limiting block (5.4) to clamp the anchor rod body (3). Fourth step, rotate the pull nut (5.1) to force the pull screw (5.2) to move away from the rock mass (1), thereby stretching the anchor rod (3) out of the hole until the pull load on the anchor rod (3) reaches the preset target, and stop rotating the pull nut (5.1). Fifth step, while maintaining the pre-tightened state of the anchor rod body (3) in the previous step, heat the heating wires in the hot melt adhesive layer (4.1) on the anchor rod body (3) except for the tail end, and stop heating after the hot melt adhesive has completely melted and bonded to the inner wall of the borehole (2); Step 6: Remove the pulling mechanism (5) and cut off the remaining anchor rod (3) outside the hole to achieve non-destructive light-micro reinforcement of the rock mass of the stone cultural relic.

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