Tunnel segmented radial anchor

Abstract

This invention relates to the field of anchor bolt construction equipment in tunnel construction, specifically a segmented radial anchor bolt for tunnels. It aims to improve the prestress of the anchor bolt arch and provide a more convenient assembly and adjustment mechanism. The anchor bolt in this invention comprises multi-stage anchor bolts assembled along the axial direction. Each stage of the anchor bolt has a reverse expansion positioning mechanism at its outer end. In addition to the end anchor bolt, each reverse expansion positioning mechanism also has a fluid passage hole. When open, each reverse expansion positioning mechanism is shaped like a supporting umbrella, with the outer diameter of each umbrella decreasing progressively from the outside in. The advantages are: it ensures the radial insertion of the anchor bolt into the surrounding rock in space-constrained construction environments, improving the anchoring effect. It is the first time that a stepped grouting structure has been proposed, resulting in better mechanical properties of the anchor bolt.

Description

Technical Field

[0001] This invention relates to the field of anchor bolt construction equipment, and in particular to a segmented radial anchor bolt for tunnels. Background Technology

[0002] In tunnel construction, the initial support and lining are crucial and necessary steps. Their stable construction is key to ensuring the success of subsequent steps. In particular, the installation of anchor bolts involves driving the bolts into the rock mass through anchor holes, and then using nuts to screw the bolts at the ends of the anchor bolts onto the inside of the anchor holes to establish an effective connection between the surrounding rock and the anchor bolts.

[0003] In tunnel construction, soil anchors are retaining structures formed by bonding reinforcing bars (or steel strands) to the soil using cement mortar in boreholes within stable soil layers. They consist of an external anchor, a free section, and an anchoring section. The external anchor connects to the retaining structure and secures the tie rod. The free section transmits the tension at the anchor head to the anchor body, applying prestress to the anchor rod. The anchoring section bonds the prestressing tendons to the soil layer using bonding materials, transmitting the tension from the free section to deeper layers through the adhesive friction between the anchor body and the soil, or through the bearing capacity of the anchor body. The anchor structure is relatively simple; current improvements mainly focus on material improvements, increasing material hardness, or refining the joints to improve compatibility with other components.

[0004] However, the applicant believes that the current technology has room for improvement, specifically in the following aspects: 1. The anchoring strength is not uniform throughout; the bottom layer of the anchor often bears greater tensile force, requiring better mechanical properties, which current technology cannot achieve through stepped grouting; 2. Anchor hole processing is prone to collapse, making it difficult for subsequent anchors to reach the correct position; 3. The anchor is generally long and slender, which is inconvenient for assembly and results in poor bending resistance; 4. Installation space inside the tunnel is limited, and under certain working conditions, the anchor is too long, requiring non-radial insertion into the surrounding rock, which cannot achieve the desired anchoring effect. In summary, there is a current need for a method and equipment to improve the prestress of the anchor arch, providing a more convenient assembly and debugging solution. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for improving the prestress of anchor bolts in arch formation, and to provide a workpiece that is easier to assemble and debug.

[0006] The specific solution of the present invention is as follows: A tunnel segmented radial anchor bolt forms a support layer. The support layer includes multiple fully threaded tunnel segmented radial anchor bolts, which are radially inserted into the surrounding rock profile. Each tunnel segmented radial anchor bolt comprises multi-stage anchoring units assembled along the axial direction. Each anchoring unit has a reverse expansion positioning mechanism fitted at its outer end. In addition to the end anchor bolt, each reverse expansion positioning mechanism also has a fluid passage hole. The reverse expansion positioning mechanism, when open, is umbrella-shaped. From the outside in, the outer diameter of the umbrella on each anchoring unit decreases progressively to form a crown-shaped support layer with a gradually decreasing diameter from the outside in. The reverse expansion positioning mechanism includes a steel expansion anchor head and an umbrella-shaped expansion anchor body. The expansion anchor body has a central hole with a diameter larger than the diameter of the anchoring unit but smaller than the outer diameter of the expansion anchor head. Adjacent anchoring units are fitted at the ends of the anchoring units, and the expansion anchor head is threadedly connected to the ends of the anchoring units. The expansion anchor head has a groove for slurry passage.

[0007] In practice, the multi-level anchor bolt includes several anchoring units, and each anchoring unit is connected by a snap-fit ​​connection.

[0008] In specific implementation, the snap-fit ​​connection includes a female buckle installed at the tail of the anchoring unit and a male buckle installed at the head of the anchoring unit. The female buckle includes a snap-fit ​​hole with a square spring block inside. The male buckle includes a snap-fit ​​shaft with a square spring block hole that matches the shape and position of the spring block. The spring block and the snap-fit ​​hole are connected by a spring.

[0009] In a specific implementation, the fluid is distributed on the expansion anchor body through holes, with the fluid through the hole axis pointing towards the central axis of the anchor rod.

[0010] In practice, the expansion anchor head is cylindrical or frustum-shaped, and its minimum outer diameter is not greater than the diameter of the central hole.

[0011] An anchor drilling rig for use with the aforementioned segmented radial anchor bolts in tunnels includes a drill rod formed by a plunger-type hydraulic cylinder, a drive mechanism for rotating the drill rod, and a drill bit mounted on the top of the drill rod. The aspect ratio of the plunger-type hydraulic cylinder is less than 1 / 20. In the fully extended state of the plunger-type hydraulic cylinder, the outer diameter of each telescopic column decreases sequentially upwards from the automatic force source. The dimensional difference of the outer diameter of each telescopic column is less than 6 cm. The outer diameter of each telescopic column corresponds to the outer diameter of each supporting umbrella. The drill rod is externally fitted with a reinforcing wear-resistant plate, and sealing rings are installed between each telescopic column.

[0012] In specific implementation, a hydraulic pipe limiting mechanism is provided below the bottom telescopic column. The hydraulic pipe limiting mechanism includes an inner ring that rotates with the hydraulic pipe and an outer ring fixed on the frame. A rolling element is provided between the inner ring and the outer ring.

[0013] In practice, the hydraulic pipe inlet is connected to a hydraulic control mechanism, and the hydraulic control mechanism is equipped with a fast directional valve controlled by an electromagnetic relay.

[0014] In practice, a water-cooling pipe is provided outside the anchoring hole on the surrounding rock to inject water into the anchoring hole.

[0015] The drill bit is a YE anchor bolt drilling bit.

[0016] The beneficial effects of this invention are as follows: In space-constrained construction environments, this ensures that the anchor bolts are radially inserted into the surrounding rock, thereby improving the anchoring effect.

[0017] For the first time, it was proposed that the mechanical properties of anchor bolts are better in a stepped molding grouting structure; The design of the fluid flow through the orifice reduces the impact of the equipment on the grout flow to blockage. The multiple orifices are evenly distributed, which can effectively maintain the mechanical balance in the orifice, whether in the drilling or grouting stage. The step-by-step drilling method, with the drill bit drilling the hole and the plunger cylinder expanding the hole, along with the control of speed and direction, forms a reasonable and effective anchor hole processing scheme, which effectively prevents anchor hole collapse and facilitates anchor rod positioning. The progressive expansion of the anchor body size provides a reference for the assembly sequence of the anchor bolts and supports the stepped grouting, effectively preventing misalignment or eccentricity. Attached Figure Description

[0018] Figure 1 This is a front view of the structure of the present invention; Figure 2 This is a left view of the structure of the present invention; Figure 3 This is the present invention. Figure 2 A sectional view of section AA in the middle; Figure 4 This is the present invention. Figure 3 Enlarged view of a section at point B in the middle; Figure 5 This is a perspective view of the structure of the present invention; Figure 6 This is a schematic diagram of the grouting process in this invention; Figure 7 This is a schematic diagram of the anchor drilling rig in this invention; The components in the diagram are named as follows: 1. Surrounding rock through which the anchor passes; 2. Anchoring unit; 3. Female buckle; 4. Female buckle; 5. Spring block; 6. Spring; 7. Expansion anchor body; 8. Expansion anchor head; 9. Fluid passage hole; 10. Groove; 11. Center hole; 12. Piston-type hydraulic cylinder; 13. Hydraulic pipeline; 14. Outer ring; 15. Inner ring; 16. Drill bit; 17. Drive mechanism; 18. Anchoring forming structure; 19. Water cooling pipeline. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Example

[0020] A segmented radial anchor bolt for tunnels, see Figures 1 to 7 The design incorporates anchor bolts to form a support layer, which includes multiple fully threaded tunnel segmented radial anchor bolts. These anchor bolts are radially inserted into the surrounding rock profile. Each segmented radial anchor bolt comprises multi-stage anchoring units 2 assembled along the axial direction. Each anchoring unit 2 has a reverse expansion positioning mechanism fitted at its outer end. In addition to the end anchor bolt, each reverse expansion positioning mechanism also has a fluid passage hole 9. The reverse expansion positioning mechanism, when open, resembles a supporting umbrella. From the outside inwards, the supporting umbrellas on each anchoring unit 2... The outer diameter of the structure decreases gradually to form a crown-shaped support layer with the diameter decreasing from the outside to the inside. The reverse expansion positioning mechanism includes a steel expansion anchor head 8 and an umbrella-shaped expansion anchor body 7. The expansion anchor body 7 is provided with a central hole 11. The diameter of the central hole 11 is larger than the diameter of the anchoring unit 2 and smaller than the outer diameter of the expansion anchor head 8. The end of the anchoring unit 2 is fitted with an adjacent anchoring unit 2. The end of the anchoring unit 2 is connected to the expansion anchor head 8 via a threaded connection. The expansion anchor head 8 is provided with a groove 10 for grout passage.

[0021] The multi-stage anchor bolt includes several anchoring units 2, and each anchoring unit 2 is connected by a snap-fit ​​connection.

[0022] The snap-fit ​​connection includes a female buckle 3 installed at the tail of the anchoring unit 2 and a male buckle 4 installed at the head of the anchoring unit 2. The female buckle 3 includes a snap-fit ​​hole, and a square spring block 5 is provided in the snap-fit ​​hole. The male buckle 4 includes a snap-fit ​​shaft, and a square spring block 5 hole that is shaped and positioned to fit the spring block 5 is provided on the corresponding snap-fit ​​shaft. The spring block 5 and the snap-fit ​​hole are connected by a spring 6.

[0023] The fluid is distributed on the expansion anchor body through hole 9, and the fluid through the hole axis of hole 9 is directed toward the central axis of the anchor rod.

[0024] The expansion anchor head 8 is cylindrical or frustum-shaped, and its minimum outer diameter is not greater than the diameter of the central hole 11.

[0025] During construction, segmented anchor bolts are inserted into the anchor holes one by one, using an assembly structure. This reduces transportation difficulties and prevents excessive length from hindering assembly. The bolts are assembled to the required predetermined length using a snap-fit ​​connection. The square spring block 5 design further ensures precise engagement and prevents twisting after assembly. Simultaneously, the short length of each anchoring unit 2 improves the overall bending resistance from the sides. Once the anchor rod is in place, it rotates in the opposite direction of the thread. At this time, the expansion anchor body 7 and the expansion anchor head 8 are restricted by the external rock strata and will not rotate with it. The expansion anchor head 8 will move toward the expansion anchor body 7, thereby causing the expansion anchor body 7 to expand and form further fixation in the rock strata. After that, grouting is carried out. During the grouting process, the presence of the hole 9 prevents the grout from being blocked by the expansion anchor body 7, and the grouting process can be completed smoothly.

[0026] Since the outer diameter of the support umbrella on each anchoring unit 2 decreases step by step from the outside to the inside, it provides support for installation in the tapered hole.

[0027] An anchor drilling rig for use with the aforementioned segmented radial anchor bolts in tunnels includes a drill rod formed by a plunger-type hydraulic cylinder 12, a drive mechanism 17 that drives the drill rod to rotate, and a drill bit 16 installed on the top of the drill rod. The aspect ratio of the plunger-type hydraulic cylinder 12 is less than 1 / 20. In the fully extended state of the plunger-type hydraulic cylinder 12, the outer diameter of each telescopic column decreases sequentially upwards from the automatic force source. The dimensional difference of the outer diameter of each telescopic column is less than 6 cm. The outer diameter of each telescopic column corresponds to the outer diameter of each supporting umbrella. The drill rod is externally reinforced with wear-resistant plates, and sealing rings are installed between each telescopic column.

[0028] In this embodiment, the main drilling mechanism is still the drill bit 16, and the plunger-type hydraulic cylinder 12 plays the role of squeezing and expanding the hole. After the entire drilling and hole expansion process is completed, the anchor rod is installed, and then grouting is performed. During the grouting process, the size of the expanding anchor body 7 is designed to support the anchor rod fixation and grouting, and finally forms a progressively shrinking grouting structure.

[0029] During operation, a hydraulic pipe limiting mechanism is installed below the lowest telescopic column. This mechanism includes an inner ring 15 that rotates with the hydraulic pipe and an outer ring 14 fixed to the frame. A rolling element is provided between the inner ring 15 and the outer ring 14. The design principle of the inner and outer rings 14 and the rolling element is the same as that of a rolling bearing, ensuring that the hydraulic pipe will not seize up.

[0030] The hydraulic pipe inlet is connected to a hydraulic control mechanism, which is equipped with a fast-reversing valve controlled by an electromagnetic relay. This design can reasonably and timely control the flow rate and direction of the hydraulic oil circuit, thereby controlling the drilling speed and direction, ensuring slow drilling and hole enlargement, while also possessing the ability to push back. Through reasonable drilling and hole enlargement processing methods, it effectively prevents the phenomenon of hole collapse within the anchor hole.

[0031] On the surrounding rock, a water-cooling pipe 19 is provided outside the anchoring hole to inject water into the anchoring hole.

[0032] The drill bit 16 is a YE anchor bolt construction drill bit 16.

[0033] In practice, anchor bolts can be hollow or solid, depending on the hardness of the rock strata on site.

[0034] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A segmented radial anchor bolt for tunnels, forming a support layer, wherein the support layer includes a plurality of fully threaded segmented radial anchor bolts, the segmented radial anchor bolts being inserted in a divergent manner into the surrounding rock profile, characterized in that: The tunnel segmented radial anchor bolt includes multi-stage anchoring units (2) assembled along the axial direction. Each anchoring unit (2) has a reverse expansion positioning mechanism installed at its outer end. In addition to the end anchor bolt, each reverse expansion positioning mechanism is also provided with a fluid passage hole (9). The reverse expansion positioning mechanism is in the shape of a supporting umbrella when it is open. From the outside to the inside, the outer diameter of the supporting umbrella on each anchoring unit (2) decreases step by step to form a crown-shaped support layer with the diameter gradually decreasing from the outside to the inside. The reverse expansion positioning mechanism includes a steel expansion anchor head (8) and an umbrella-shaped expansion anchor body (7). The expansion anchor body (7) is provided with a central hole (11). The diameter of the central hole (11) is larger than the diameter of the anchoring unit (2) and smaller than the outer diameter of the expansion anchor head (8). The end of the anchoring unit (2) is fitted with an adjacent anchoring unit. (2) The end of the anchoring unit (2) is connected to the expansion anchor head (8) via a threaded connection; the expansion anchor head (8) is provided with a groove (10) for slurry passage; the anchoring units (2) are provided with a snap-fit ​​connection; the snap-fit ​​connection includes a female buckle (3) installed at the tail of the anchoring unit (2) and a male buckle (4) installed at the head of the anchoring unit (2). The female buckle (3) includes a snap-fit ​​hole, and a square spring block (5) is provided in the snap-fit ​​hole. The male buckle (4) includes a snap-fit ​​shaft, and a square spring block hole that fits with the spring block (5) is provided on the corresponding snap-fit ​​shaft. The spring block (5) is connected to the snap-fit ​​hole via a spring (6). The fluid passage hole (9) is arranged on the expansion anchor body (7), and the hole axis of the fluid passage hole (9) faces the central axis of the anchor rod.

2. The tunnel segmented radial anchor bolt as described in claim 1, characterized in that: The expansion anchor head (8) is cylindrical or frustum-shaped, and its minimum outer diameter is not greater than the diameter of the central hole (11).

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