Magnetic expanding anchor rod and construction method thereof

Abstract

The application provides a magnetic expanding head anchor rod and a construction method thereof. The expanding head anchor rod comprises a main steel anchor rod, a pull steel anchor rod, a first supporting steel disc, a magnetic anchor rod expanding head and a plurality of expanding anchor rods. The first supporting steel disc is welded on the main steel anchor rod, the pull rod anchor rod is connected with the magnetic anchor rod expanding head through the main steel anchor rod. The magnetic anchor rod expanding head comprises a second supporting steel disc and a magnet block welded on the side of the second supporting steel disc away from the pull steel anchor rod. A plurality of strip-shaped holes are distributed on the disc surface of the second supporting steel disc in the radial direction. A connecting spring is arranged between the two supporting steel discs. The plurality of expanding anchor rods are distributed around the pull steel anchor rod with the pull steel anchor rod as the center. One end of each expanding anchor rod is movably connected with the first supporting steel disc, the other end passes through the corresponding strip-shaped hole of the second supporting steel disc and extends to the outside of the magnet block. The application is favorable for attracting magnetic concrete, making the concrete gather more densely, expelling excess air and increasing the stability and tensile resistance of the anchor rod.

Description

Technical Field

[0001] This invention relates to the field of slope management, specifically to a magnetic extended-head anchor bolt and its construction method. This tunnel structure is used in steep slope sections in plateau and mountainous areas, and enables rapid construction and repair of damaged tunnel sections. Background Technology

[0002] The steep slopes of high-altitude mountainous regions make them prone to natural disasters such as rainstorms, floods, landslides, and earthquakes. The complex geological structure further exacerbates the instability of steep slopes, making them susceptible to collapses and landslides. In winter, snowstorms and avalanches are also common, posing significant challenges to road operation and construction.

[0003] Anchor bolt reinforcement is an indispensable engineering method for slope protection. Traditional anchor bolts are mainly used for rock and soil anchoring projects on high slopes such as highways, railways, and foundation pits. Their characteristic is that the anchor bolt is driven into the soil layer and then grouted to form a unified whole with the soil. Traditional anchor bolts have relatively low anchoring capacity and low tensile strength. Moreover, because the grout used for anchor bolts is generally ordinary concrete grout, to avoid backflow during the grouting process, existing anchor bolts can only be driven downwards, not upwards, thus limiting their application. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a magnetic expanded-head anchor rod and its construction method. This anchor rod is beneficial for attracting magnetic concrete, making the concrete more compact, displacing excess air, increasing the stability and tensile strength of the anchor rod, and enabling grouting at an upward angle, thus increasing the construction range of the anchor rod.

[0005] To achieve the above-mentioned technical objectives, the present invention provides a magnetic expansion head anchor bolt, which includes a main steel anchor bolt, a tension steel anchor bolt, an expansion anchor bolt, a first support steel disc, and a magnetic anchor bolt expansion head; the first support steel disc is welded to one end of the main steel anchor bolt near the anchor head, and the tension steel anchor bolt passes through the main steel anchor bolt and connects to the magnetic anchor bolt expansion head; the magnetic anchor bolt expansion head includes a second support steel disc fixed to the end of the tension steel anchor bolt and a magnet welded to the side of the second support steel disc away from the tension steel anchor bolt, the diameter of the second support steel disc is larger than that of the first support steel disc, and multiple strip holes are radially distributed on the surface of the second support steel disc, the multiple strip holes being distributed in a ring with the connection point between the tension steel anchor bolt and the second support steel disc as the center;

[0006] A connecting spring is provided between the first support steel plate and the second support steel plate. The connecting spring is sleeved on the outside of the main steel anchor and the tension steel anchor, with one end connected to the first support steel plate and the other end connected to the second support steel plate. There are multiple expansion anchors, which are distributed around the tension steel anchor with the tension steel anchor as the center. One end of each expansion anchor is movably connected to the first support steel plate, and the other end passes through the corresponding strip hole of the second support steel plate and extends to the outside of the magnet block.

[0007] When the magnetic expansion anchor rod is inserted into the anchor hole, the connecting spring is in the normally extended state. When the steel anchor rod is pulled, the steel anchor rod drives the second support steel plate to move towards the first support steel plate, the connecting spring is compressed, and multiple expansion anchor rods slide and expand in the corresponding strip holes.

[0008] The preferred technical solution of the present invention is as follows: the anchor hole includes an anchor bolt hole and an enlarged head hole. The outer diameter of the anchor bolt hole matches the outer diameter of the magnetic anchor bolt expansion head when it is not expanded, and the enlarged head hole matches the maximum diameter of the multiple expanded anchor bolts of the magnetic anchor bolt expansion head in the expanded state. After the enlarged head anchor bolt is installed into the anchor hole, magnetic concrete is poured and filled into the anchor bolt hole and the enlarged head hole.

[0009] A preferred technical solution of the present invention is as follows: 3 to 5 expansion anchor rods are provided. An anchor rod through hole is opened at the center of the first support steel plate. Multiple pull holes are distributed in a ring around the anchor rod through hole on the annular surface of the first support steel plate. The pull steel anchor rod passes through the anchor rod through hole, and the other end is fixedly welded to the center of the second support steel plate or fixedly inserted into the center hole of the second support steel plate. The number of pull holes and strip holes is the same as the number of expansion anchor rods. Each expansion anchor rod has a connecting ring at one end, and the connecting ring is sleeved with the pull hole.

[0010] The preferred technical solution of the present invention is as follows: the magnet block is frustum-shaped or I-shaped, and the diameter of the end of the magnet block near the second supporting steel plate is smaller than the diameter of the end away from the second supporting steel plate. The outer diameter of the large diameter end of the magnet block matches the maximum diameter of the multiple expansion anchor rods in the unexpanded state. During the process of inserting the magnetic expansion anchor rod into the hole, the elastic force provided by the connecting spring keeps the expansion anchor rod in a non-opening state. At this time, the end of the expansion anchor rod away from the first supporting steel plate is located outside the large diameter end of the magnet block and contacts the outer edge of the large diameter end of the magnet block.

[0011] The preferred technical solution of the present invention is that the main steel anchor rod is slidably sleeved on the outside of the tie rod anchor rod.

[0012] A further technical solution of the present invention: The magnetic concrete is composed of the following materials in the following mass percentages: 25-35% iron ore crushed stone with a particle size of 5-10mm, 15-25% iron powder, 20-30% cement, 2-4% SBS modifier, 6-8% glass fiber with a length of 15-20mm and 12-17% water.

[0013] This invention also provides a construction method for a magnetic expansion anchor bolt, characterized by the following specific steps:

[0014] S1. Use a drilling rig to drill anchor bolt holes from the anchor bolt installation point. The inner diameter of the anchor bolt hole is greater than or equal to the outer diameter of the maximum diameter part of the magnetic anchor bolt expansion head when it is not expanded.

[0015] S2. Continue drilling from the deepest part of the anchor bolt hole using a reaming drill bit to form a reaming hole. The inner diameter of the reaming hole is greater than or equal to the outer diameter of the part with the maximum diameter when the magnetic anchor bolt expansion head is in the expanded state.

[0016] S3. Insert the magnetic expansion head anchor rod into the drilled anchor bolt hole, with its magnetic expansion head placed inside the expansion head hole. Pull the steel anchor rod to drive the second support steel plate to move toward the first support steel plate. The connecting spring is compressed, and multiple expansion anchor rods slide outward simultaneously in the corresponding strip holes. When the expansion anchor rods are expanded to the maximum diameter of the expansion head hole, fix the position of the steel anchor rod.

[0017] S4. Inject magnetic concrete into the anchor hole and use a magnet to attract the magnetic concrete to fill the gaps in the anchor hole. Once the magnetic concrete has solidified, the installation of the magnetic expanded head anchor is complete.

[0018] A further technical solution of the present invention: when the magnetic expanded head anchor rod is installed, its drill hole is inclined downward or inclined upward; when the drill hole is inclined upward, its inclination angle is 0 to 90 degrees, and the grouting method is upward grouting.

[0019] A further technical solution of the present invention: In step S3, when the magnetic expansion anchor rod is inserted into the anchor rod hole, the connecting spring is in an extended state and provides elastic force to keep the expansion anchor rod in a non-open state. The end of the expansion anchor rod away from the first support steel plate is located outside the large diameter end of the magnet block and is fixed by the magnet block.

[0020] A further technical solution of the present invention: In step S4, the magnetic concrete is prepared by mixing the following materials in the following mass percentages: 25-35% iron ore crushed stone with a particle size of 5-10mm, 15-25% iron powder, 20-30% cement, 2-4% SBS modifier, 6-8% glass fiber with a length of 15-20mm and 12-17% water.

[0021] The beneficial effects of this invention are:

[0022] (1) In this invention, a magnet is welded to the front end of the expansion head of the expansion head of the anchor rod, which is beneficial to attract the expansion head of the anchor rod to the magnet, making it convenient for the device to be inserted into the magnetic expansion head of the anchor rod hole. When the bottom is opened by tensioning, the magnetic expansion head of the anchor rod is opened. The front magnet is also beneficial to attract magnetic concrete to gather more densely and displace excess air.

[0023] (2) The grouting slurry of the present invention uses magnetic concrete. The magnetic concrete, together with the magnetic expansion anchor, can achieve upward grouting. During the grouting process, the magnet at the front end of the anchor expansion head can attract the magnetic concrete. The magnetic concrete poured in front is attracted and comes into contact with the magnet. Then the magnetic concrete also becomes magnetic and continues to attract the subsequent magnetic concrete, thereby achieving upward grouting.

[0024] (3) The magnetic concrete mix proportion and the addition of modifier and glass fiber in this invention are beneficial to make the concrete more dense and displace air by utilizing the mutual attraction between magnets.

[0025] (4) In this invention, the first supporting steel plate is welded in the middle of the magnetic expansion head anchor rod, and the connecting ring of the expansion anchor rod is inserted into the hole of the first supporting steel plate, which can provide the reinforcing steel of the expansion head to the front end device of the main steel anchor rod; the magnet is welded to the front end of the magnetic expansion head anchor rod, which is conducive to attracting the expansion anchor rod to the magnet, making it convenient for the device to be inserted into the magnetic expansion head anchor rod hole. When the bottom is opened by tensioning, the front end magnet is also conducive to attracting magnetic concrete to gather; the magnet block in this invention is set with an I-shaped cross section, which can save costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the magnetic expansion head anchor rod of the present invention in its unexpanded state;

[0027] Figure 2 This is a schematic diagram of the expansion state of the magnetic expansion head anchor bolt in this invention;

[0028] Figure 3 This is a plan view of the first supporting steel disc in this invention;

[0029] Figure 4 This is a plan view of the second supporting steel disc in this invention;

[0030] Figure 5 This is a schematic diagram of the magnetic expansion anchor rod being installed in the anchor hole in this invention;

[0031] Figure 6 This is a schematic diagram of the magnetic expanded head anchor rod after grouting in the anchor hole in this invention;

[0032] Figure 7 This is a schematic diagram of the magnet block structure with an I-shaped cross-section in this invention;

[0033] Figure 8 This is a schematic diagram of the magnet block structure with a frustum-shaped cross-section in this invention.

[0034] In the diagram: 500, main steel anchor bolt; 501, tension steel anchor bolt; 502, expansion anchor bolt; 503, first support steel plate; 504, second support steel plate; 505, magnet block; 506, connecting spring; 507, pull hole; 508, strip hole; 509, connecting ring; 510, anchor hole; 511, magnetic concrete. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Figures 1 to 8 All accompanying drawings are simplified versions of embodiments and are intended only to clearly and concisely illustrate the embodiments of the present invention. The technical solutions shown in the drawings below are specific solutions of embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] A magnetic expansion head anchor bolt provided in the embodiment, such as Figures 1 to 8The magnetic expansion head anchor bolt includes a main steel anchor bolt 500, a tension steel anchor bolt 501, an expansion anchor bolt 502, a first support steel plate 503, and a magnetic anchor bolt expansion head; the magnetic anchor bolt expansion head includes a second support steel plate 504 fixed to the end of the tension steel anchor bolt 501 and a magnet block 505 welded to the side of the second support steel plate 504 away from the tension steel anchor bolt 501, the diameter of the second support steel plate 504 being larger than that of the first support steel plate 503; the expansion anchor bolt 502 has four bolts, the first... The supporting steel plate 503 is welded to one end of the main steel anchor rod 500 near the anchor head. An anchor rod through hole is opened at the center of the first supporting steel plate 503. Four pull holes 507 are distributed in a ring around the anchor rod through hole on the annular surface of the first supporting steel plate 503. The pull steel anchor rod 501 passes through the anchor rod through hole, and the other end is fixedly welded to the center of the second supporting steel plate 504 or fixedly inserted into the center hole of the second supporting steel plate 504. The main steel anchor rod 500 is slidably sleeved on the pull rod anchor rod 501. Four strip-shaped holes 508 are radially distributed on the surface of the second support steel plate 504. The four strip-shaped holes 508 are arranged in a ring with the connection point between the tension steel anchor rod 501 and the second support steel plate 504 as the center. A connecting spring 506 is provided between the first support steel plate 503 and the second support steel plate 504. The connecting spring 506 is sleeved on the outside of the main steel anchor rod 500 and the tension steel anchor rod 501. One end is connected to the first support steel plate 503 and the other end is connected to the second support steel plate 504. Each expansion anchor rod 502 has a connecting ring 509 at one end. The connecting ring 509 is sleeved at the tension hole 507 and is movable. The other end passes through the corresponding strip-shaped hole 508 of the second support steel plate 504 and extends to the outside of the magnet block 505. When the magnetic expanding anchor rod is inserted into the anchor hole 510, the connecting spring 506 is in the normally extended state. When the steel anchor rod 501 is pulled, the steel anchor rod 501 drives the second support steel plate 504 to move toward the first support steel plate 503, the connecting spring 506 is compressed, and the four expanding anchor rods 502 slide and expand in the corresponding strip hole 508.

[0038] In this embodiment, the anchor hole 510 includes an anchor bolt hole and an enlarged head hole. The anchor bolt hole matches the outer diameter of the magnetic anchor bolt expansion head when it is not expanded, and the enlarged head hole matches the maximum diameter of the multiple expanded anchor bolts 502 of the magnetic anchor bolt expansion head in their expanded state. After the enlarged head anchor bolt is installed into the anchor hole 510, magnetic concrete is poured and filled into the anchor bolt hole and the enlarged head hole. Figure 7 and Figure 8 As shown, the magnet block 505 is frustum-shaped or I-shaped. Setting it to an I-shape saves costs, and the diameter of the end of the magnet block 505 near the second support steel plate 504 is smaller than the diameter of the end away from the second support steel plate 504; during the process of inserting the magnetic expansion head anchor rod into the hole, as... Figure 1As shown, the connecting spring 506 is in the extended state, and the elastic force it provides keeps the expansion anchor 502 in the non-open state. At this time, the end of the expansion anchor 502 away from the first support steel plate 503 is located outside the large-diameter end of the magnet block 505 and contacts the outer edge of the large-diameter end of the magnet block 505. The purpose of setting the magnet in the magnetic anchor expansion head is to facilitate the attraction of the expansion anchor 502 to the magnet, making it easier for the device to be inserted into the magnetic expansion head anchor hole. When the bottom is opened by tensioning, the front magnet also helps to attract magnetic concrete to gather. The designed spring helps to give the magnetic expansion head anchor a spring force during the insertion process, generate a rebound force when encountering resistance, and spring back when there is no resistance, ensuring that the magnetic expansion head anchor is placed in the designed position of the hole.

[0039] The magnetic concrete being implemented consists of the following materials by weight percentage: 30% iron ore crushed stone with a particle size of 5-10mm, 20% iron powder, 25% cement, 3% SBS modifier, 7% 19mm long glass fiber, and 15% water.

[0040] The construction method of a magnetic expansion head anchor provided in the embodiment includes the following specific steps:

[0041] S1. Use a drilling rig to drill anchor bolt holes from the anchor bolt installation point. The inner diameter of the anchor bolt hole is greater than or equal to the outer diameter of the maximum diameter part of the magnetic anchor bolt expansion head when it is not expanded.

[0042] S2. Continue drilling from the deepest part of the anchor bolt hole using a reaming drill bit to form a reaming hole. The inner diameter of the reaming hole is greater than or equal to the outer diameter of the part with the maximum diameter when the magnetic anchor bolt expansion head is in the expanded state.

[0043] S3. Insert the magnetic expansion head of the anchor rod into the drilled anchor hole, with the magnetic expansion head positioned inside the expansion head hole; as follows. Figure 3 As shown, when the magnetic expansion anchor is inserted into the anchor hole, the connecting spring is in an extended state, providing elastic force to keep the expansion anchor in a non-open state. The end of the expansion anchor away from the first support steel plate is located outside the large-diameter end of the magnet block and is fixed by the magnet block; as Figure 4 As shown, pulling the steel anchor rod causes the second support steel plate to move toward the first support steel plate, and the connecting spring is compressed. Multiple expansion anchor rods slide outward simultaneously in the corresponding strip holes, and the position of the steel anchor rod is fixed when the expansion anchor rods are expanded to the maximum diameter of the expansion head hole.

[0044] S4. Inject magnetic concrete into the anchor hole and use a magnet to attract the magnetic concrete to fill the gaps in the anchor hole. Once the magnetic concrete has solidified, the installation of the magnetic expanded head anchor is complete.

[0045] In this invention, the magnetic expanded-head anchor rod is installed with its drill hole tilted downwards or upwards; when the drill hole is tilted upwards, the tilt angle is 0-90 degrees, and the grouting method is upward-looking grouting. Regarding the use of magnetic concrete and magnetic anchor rods to achieve upward-looking grouting, the inventors of this application conducted experiments in the laboratory, and the tilt angle can reach 90°, achieving vertical upward-looking grouting; in specific construction, the magnetic force of the magnet can be adjusted according to the depth of the anchor rod on site to achieve upward-looking grouting. The experiments of this invention prove that the magnetic grout viscosity is 12464 MPa / s and under the attraction of a magnetic rod with a magnetic field strength of 12000 GS, it can basically grout a 420 cm diameter within 4 minutes. 3 The inverted container was filled completely. After filling, the container was allowed to stand for 10 minutes to allow excess grout to drain out under gravity. Then, the top magnet and the transparent container were removed. The adhesion of the grout to the rod-shaped magnet was observed, and its maximum adsorption diameter of 4 cm was measured. This provides technical support for large-scale overhead borehole grouting in later projects.

[0046] The above description is merely one embodiment of the present invention, and while it is detailed and specific, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A magnetic expansion head anchor bolt, characterized in that: The expanded head anchor bolt includes a main steel anchor bolt (500), a tension steel anchor bolt (501), an expansion anchor bolt (502), a first support steel disc (503), and a magnetic anchor bolt expansion head; the first support steel disc (503) is welded to one end of the main steel anchor bolt (500) near the anchor head, and the tension steel anchor bolt (501) passes through the main steel anchor bolt (500) and connects to the magnetic anchor bolt expansion head; the magnetic anchor bolt expansion head includes a second support steel disc (504) fixed to the end of the tension steel anchor bolt (501) and a magnet block (505) welded to the side of the second support steel disc (504) away from the tension steel anchor bolt (501), the diameter of the second support steel disc (504) is larger than that of the first support steel disc (503), and multiple strip holes (508) are radially distributed on the surface of the second support steel disc (504), and the multiple strip holes (508) are distributed in a ring with the connection point between the tension steel anchor bolt (501) and the second support steel disc (504) as the center; A connecting spring (506) is provided between the first support steel plate (503) and the second support steel plate (504). The connecting spring (506) is sleeved on the outside of the main steel anchor rod (500) and the tension steel anchor rod (501). One end is connected to the first support steel plate (503), and the other end is connected to the second support steel plate (504). There are multiple expansion anchor rods (502), which are distributed around the tension steel anchor rod (501) with the tension steel anchor rod (501) as the center. One end of each expansion anchor rod (502) is movably connected to the first support steel plate (503), and the other end passes through the corresponding strip hole (508) of the second support steel plate (504) and extends to the outside of the magnet block (505). When the magnetic expansion anchor rod is inserted into the anchor hole (510), the connecting spring (506) is in the normal extended state. When the steel anchor rod (501) is pulled, the steel anchor rod (501) drives the second support steel plate (504) to move toward the first support steel plate (503), the connecting spring (506) is compressed, and multiple expansion anchor rods (502) slide and expand in the corresponding strip hole (508); The expansion anchor rod (502) is provided with 3 to 5 rods. An anchor rod through hole is opened at the center of the first support steel plate (503). The annular surface of the first support steel plate (503) is provided with multiple pull holes (507) arranged in a ring with the anchor rod through hole as the center. The pull steel anchor rod (501) passes through the anchor rod through hole, and the other end is fixedly welded to the center of the second support steel plate (504) or fixedly inserted into the center hole of the second support steel plate (504). The number of pull holes (507) and strip holes (508) is the same as the number of expansion anchor rods (502). Each expansion anchor rod (502) is provided with a connecting ring (509) at one end, and the connecting ring (509) is sleeved with the pull hole (507). The magnet block (505) is frustum-shaped or I-shaped, and the diameter of the end of the magnet block (505) near the second support steel plate (504) is smaller than the diameter of the end away from the second support steel plate (504). The outer diameter of the large diameter end of the magnet block (505) matches the maximum diameter of the multiple expansion anchor rods (502) in the unexpanded state. During the process of inserting the magnetic expansion anchor rod into the hole, the elastic force provided by the connecting spring (506) keeps the expansion anchor rod (502) in a non-open state. At this time, the end of the expansion anchor rod (502) away from the first support steel plate (503) is located outside the large diameter end of the magnet block (505) and contacts the outer edge of the large diameter end of the magnet block (505).

2. A magnetic expansion head anchor bolt according to claim 1, characterized in that: The anchor hole (510) includes an anchor bolt hole and an enlarged head hole. The anchor bolt hole matches the outer diameter of the magnetic anchor bolt expansion head when it is not expanded, and the enlarged head hole matches the maximum diameter of the multiple expansion anchor bolts (502) of the magnetic anchor bolt expansion head in the expanded state. After the enlarged head anchor bolt is installed into the anchor hole (510), magnetic concrete (511) is poured and filled into the anchor bolt hole and the enlarged head hole.

3. A magnetic expansion head anchor bolt according to claim 1 or 2, characterized in that: The main steel anchor (500) is slidably sleeved on the outside of the tension steel anchor (501).

4. A magnetic expansion head anchor bolt according to claim 2, characterized in that: The magnetic concrete is composed of the following materials by mass percentage: 25-35% iron ore crushed stone with a particle size of 5-10mm, 15-25% iron powder, 20-30% cement, 2-4% SBS modifier, 6-8% glass fiber with a length of 15-20mm, and 12-17% water.

5. A construction method for a magnetic expansion head anchor bolt according to any one of claims 1 to 4, characterized in that... The specific steps are as follows: S1. Use a drilling rig to drill anchor bolt holes from the anchor bolt installation point. The inner diameter of the anchor bolt hole is greater than or equal to the outer diameter of the maximum diameter part of the magnetic anchor bolt expansion head when it is not expanded. S2. Continue drilling from the deepest part of the anchor bolt hole using a reaming drill bit to form a reaming hole. The inner diameter of the reaming hole is greater than or equal to the outer diameter of the part with the maximum diameter when the magnetic anchor bolt expansion head is in the expanded state. S3. Insert the magnetic expansion head anchor rod into the drilled anchor bolt hole, with its magnetic expansion head placed inside the expansion head hole. Pull the steel anchor rod to drive the second support steel plate to move toward the first support steel plate. The connecting spring is compressed, and multiple expansion anchor rods slide outward simultaneously in the corresponding strip holes. When the expansion anchor rods are expanded to the maximum diameter of the expansion head hole, fix the position of the steel anchor rod. S4. Inject magnetic concrete into the anchor hole and use a magnet to attract the magnetic concrete to fill the gaps in the anchor hole. Once the magnetic concrete has solidified, the installation of the magnetic expanded head anchor is complete.

6. The construction method of a magnetic expansion head anchor bolt according to claim 5, characterized in that: When the magnetic expansion head anchor is installed, its drill hole is inclined downwards or upwards; when the drill hole is inclined upwards, its inclination angle is 0 to 90 degrees, and the grouting method is upward grouting.

7. The construction method of a magnetic expanded-head anchor bolt according to claim 5, characterized in that: In step S3, when the magnetic expansion anchor rod is inserted into the anchor rod hole, the connecting spring is in an extended state and provides elastic force to keep the expansion anchor rod in a non-open state. The end of the expansion anchor rod away from the first support steel plate is located outside the large diameter end of the magnet block and is fixed by the magnet block.

8. The construction method of a magnetic expanded-head anchor bolt according to claim 5, characterized in that: In step S4, the magnetic concrete is prepared by mixing the following materials in the following mass percentages: 25-35% iron ore crushed stone with a particle size of 5-10mm, 15-25% iron powder, 20-30% cement, 2-4% SBS modifier, 6-8% glass fiber with a length of 15-20mm, and 12-17% water.

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