A dual bit shear resistant anchor and reinforcement system

Abstract

This invention provides a dual-drill-bit shear anchor and reinforcement system, relating to the field of anchor support. It includes a first drill bit assembly, a second drill bit assembly, and a fixing connector. The second drill bit assembly is sleeved on the first drill bit assembly, and the first and second drill bit assemblies travel in the same direction. The fixing connector is sleeved on the first drill bit assembly and connected to one end of the second drill bit assembly. This invention solves problems such as insufficient shear strength in local sections of anchor bolts, inability to drill holes of different cross-sectional sizes in a single operation, complex and inefficient on-site construction, poor flexibility and adaptability, and high overall construction costs.

Description

Technical Field

[0001] This invention relates to the field of anchor bolt support, and more specifically, to a dual-drill-bit shear anchor bolt and reinforcement system. Background Technology

[0002] The reinforcement of mine tunnel structures generally employs methods such as resin anchors, slotted pipe anchors, and self-drilling hollow grouting anchors to control tensile and shear failure, achieving good reinforcement results. However, in extremely complex soil and rock conditions, severe displacement between the structure and the soil or within the soil can easily cause shear fracture of the anchor rod along its cross-section, and movement of the soil and rock, as well as the overall structure, into the void. Furthermore, the complexity of the soil and rock itself makes drilling difficult, leading to high shear strength requirements in localized areas of the reinforced structure and the need for sufficient anchor bolt anchoring force. Common solutions include increasing the anchor bolt support density or using larger diameter anchor bolts through secondary drilling to improve the shear strength and anchoring capacity of the reinforced areas. However, these measures result in reduced construction efficiency, increased construction costs, and a significantly wider range of damage to the original soil and rock structure.

[0003] The inventors discovered that in existing technologies, whether adding a connecting sleeve or a sleeve to the anchor bolt, the increase is limited to a small, fixed diameter outside the bolt body. This limited increase restricts the increase in shear strength, and most importantly, it only improves the axial shear strength of the bolt body. Furthermore, anchor bolt installation typically involves harsh environments and complex operations. The aforementioned patented anchor bolt structures are complex and require high precision, making it difficult to achieve the same shear strength test results in complex field environments. Additionally, the axial anchoring force is limited due to the single anchoring end. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-drill-bit shear anchor and reinforcement system, which can solve the problems of insufficient shear strength of anchors in local sections, inability to drill holes of different rod cross-sectional sizes in one go, complex and inefficient on-site construction, poor flexibility and adaptability, and high overall construction costs.

[0005] The embodiments of the present invention are implemented as follows:

[0006] In a first aspect, the present invention provides a double-drill-bit shear anchor bolt, comprising:

[0007] First drill bit assembly;

[0008] A second drill bit assembly is fitted onto the first drill bit assembly, and the first drill bit assembly and the second drill bit assembly travel in the same direction.

[0009] A fixing connector, which is sleeved on the first drill bit assembly and connected to one end of the second drill bit assembly;

[0010] The first drill bit assembly includes a first drill bit and an inner hollow sleeve. The outer wall of the inner hollow sleeve is provided with a first thread, and the first drill bit is threadedly connected to one end of the inner hollow sleeve.

[0011] The second drill bit assembly includes a second drill bit and an outer sleeve. The outer sleeve has a central hole that extends axially through it. The outer sleeve is threaded to the inner hollow sleeve through the central hole. The outer sleeve has a second thread on its outer wall. The second drill bit is fitted onto the inner hollow sleeve and threaded to one end of the outer sleeve. The first drill bit and the second drill bit are located on the same side.

[0012] The internal hollow casing is provided with a second overflow hole, which is located downstream of the second drill bit in the direction of travel.

[0013] In an optional embodiment, the first drill bit is provided with a first overflow hole.

[0014] In an optional embodiment, the diameter of the second drill bit is larger than the diameter of the outer casing.

[0015] In an optional embodiment, the internal hollow sleeve is provided with a second overflow hole, which is located downstream of the travel direction of the second drill bit.

[0016] In an optional embodiment, the fixing connector is provided with a connecting hole that extends axially, and the fixing connector is threadedly connected to the end of the inner hollow sleeve away from the first drill bit through the connecting hole.

[0017] In an optional embodiment, the fixing connector is further provided with a threaded groove that is opened along the axial direction, and the fixing connector is threadedly connected to the end of the outer sleeve away from the second drill bit through the threaded groove.

[0018] In an optional embodiment, the dual-bit shear anchor bolt further includes a tray connected to the outer casing and close to the fixing connector.

[0019] Secondly, the present invention provides a reinforcement system, including a dual-drill-bit shear anchor bolt as described in the foregoing embodiments.

[0020] The beneficial effects of the embodiments of the present invention are:

[0021] This invention provides a dual-drill-head shear-resistant self-rotating anchor bolt, comprising a first drill bit assembly, a second drill bit assembly, and a fixing connector. The second drill bit assembly is sleeved on the first drill bit assembly, and the first and second drill bit assemblies travel in the same direction. The fixing connector is sleeved on the first drill bit assembly and connected to one end of the second drill bit assembly. The invention features a reasonable structural design. The first and second drill bit assemblies can achieve simultaneous drilling of the same anchor bolt with different cross-sections, improving construction efficiency. The dual-drill-head design is suitable for rapid drilling under complex soil and rock conditions. Furthermore, the second drill bit assembly is sleeved on top of the first drill bit assembly, allowing for on-site assembly after determining the parameters of the second drill bit according to usage needs, thus improving the flexibility of this type of anchor bolt. The sleeved use of the two components also improves the overall local cross-sectional shear strength of the anchor bolt. In addition, the specially designed fixing connector effectively solves the connection and pre-tightening force application problems between the first and second drill bit assemblies, achieving a firm connection between them and enabling simultaneous application of pre-tightening force to both. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram illustrating the function of the dual-drill-bit anti-shear self-drilling anchor bolt provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the fixed connector structure provided in an embodiment of the present invention.

[0025] icon:

[0026] 100-First drill bit assembly; 110-First drill bit; 120-Inner hollow casing; 121-First overflow hole; 122-Second overflow hole; 200-Second drill bit assembly; 210-Second drill bit; 220-Outer casing; 300-Fixed connector; 310-Connecting hole; 320-Threaded groove; 400-Panel; 500-Grouted stone body; 600-Concrete well shaft. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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. They are 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," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] The present invention provides a reinforcement system, including a double-drill-bit shear-resistant self-drilling anchor, which is suitable for reinforcement and treatment projects of structures and buildings with high local shear strength requirements, such as mine shafts, adits, tunnels, water conservancy and building foundation pits.

[0034] Currently, existing anchor bolt technologies have many problems. For example, in terms of functionality, existing technologies often improve shear resistance from the axial direction of the bolt, without considering the shear resistance in the cross-sectional direction. From the perspective of shear resistance, existing technologies generally add connecting sleeves or sleeves to the anchor bolt, but both of these methods only add a small fixed diameter to the outside of the anchor bolt, which is limited compared to the bolt itself, thus limiting the increase in shear strength. Most importantly, they only improve the axial shear strength of the anchor bolt. From a construction perspective, anchor bolt construction is generally carried out in harsh environments and is complex. Existing anchor bolt structures are relatively complex and require high precision, making it difficult to achieve the same shear resistance test results as in laboratory tests in complex field environments. In addition, there is only one anchoring end, resulting in limited axial anchoring force. Therefore, to solve the above problems, this embodiment provides a double-rotating shear-resistant self-rotating anchor bolt.

[0035] First Embodiment

[0036] like Figure 1 As shown, the dual-head anti-shear self-rotating anchor bolt provided in this embodiment includes a first drill bit assembly 100, a second drill bit assembly 200, and a fixing connector 300. The second drill bit assembly 200 is sleeved on the first drill bit assembly 100, and the first drill bit assembly 100 and the second drill bit assembly 200 travel in the same direction. The fixing connector 300 is sleeved on the first drill bit assembly 100 and connected to one end of the second drill bit assembly 200.

[0037] It is understood that the structural design of this embodiment is reasonable. The first drill bit assembly 100 and the second drill bit assembly 200 can achieve one-time drilling of the same anchor rod with different cross-sections, which improves construction efficiency. The dual drill bits are suitable for rapid drilling under complex soil and rock conditions. In addition, the second drill bit assembly 200 is sleeved on the second drill bit assembly 210, so the parameters of the second drill bit 210 can be determined on-site according to the needs of use and then assembled on-site, thereby improving the flexibility of this type of anchor rod and improving the local cross-sectional shear strength of the anchor rod as a whole. In addition, the specially designed fixed connector 300 effectively solves the connection and pre-tightening force application problem between the first drill bit assembly 100 and the second drill bit assembly 200, realizing a firm connection between the two, and at the same time, pre-tightening force can be applied to both.

[0038] Furthermore, the first drill bit assembly 100 includes a first drill bit 110 and an inner hollow sleeve 120. A first thread (not marked in the figure) is provided on the outer wall of the inner hollow sleeve 120, and the first drill bit 110 is threadedly connected to one end of the inner hollow sleeve 120. Specifically, in this embodiment, the outer diameter of the inner hollow sleeve 120 is selected as φ25~32mm, and the sleeve wall thickness is set according to the usage requirements. On the other hand, in order to ensure that the inner hollow sleeve 120 can be smoothly brought into the borehole by the first drill bit 110, the outer diameter of the first drill bit 110 is larger than that of the inner hollow sleeve 120. This ensures that during the drilling process, the diameter of the borehole is larger than that of the inner hollow sleeve 120, and when the inner hollow sleeve 120 is inserted into the borehole, it will not deform due to pressure from the borehole wall.

[0039] Specifically, the first drill bit 110 is provided with a first overflow hole 121. In detail, the diameter of the first overflow hole 121 is 3-6 mm, and it is connected to the inner hollow sleeve 120. When grout is delivered into the inner hollow sleeve 120, the grout flows out from the first overflow hole 121. The grouting stone body 500 formed by the grout from the first overflow hole 121 encapsulates the first drill bit 110. After the grout solidifies, it acts as the first anchor point.

[0040] In this embodiment, the second drill assembly 200 includes a second drill bit 210 and an outer sleeve 220. The outer sleeve 220 has a central hole (not marked in the figure) that extends axially through it. The outer sleeve 220 is threaded to the inner hollow sleeve 120 through the central hole. The outer wall of the outer sleeve 220 has a second thread (not marked in the figure). The second drill bit 210 is sleeved on the inner hollow sleeve 120 and threaded to one end of the outer sleeve 220. The first drill bit 110 and the second drill bit 210 are located on the same side.

[0041] In detail, both the inner hollow sleeve 120 and the outer sleeve 220 have threads, and the threads and bore diameters of the two must match. The preferred outer diameter of the outer sleeve 220 is φ32-40mm, and the preferred length is 35-60cm. In addition, the front end of the outer sleeve 220 has a second drill bit 210, which is sleeved on the inner hollow sleeve 120 and threaded to one end of the outer sleeve 220; exemplaryly, in other embodiments, the second drill bit 210 may also be threaded to the inner hollow sleeve 120 and separate from the outer sleeve 220.

[0042] Furthermore, the diameter of the second drill bit 210 is larger than the diameter of the outer casing 220. Specifically, the diameter of the core drill bit is preferably 2-4 mm larger than the outer diameter of the outer casing 220. This is understandable, as it is to ensure that the outer casing 220 can be smoothly brought in during construction, avoiding deformation and damage to the outer casing 220 due to pressure from the borehole wall.

[0043] Furthermore, the inner hollow sleeve 120 is provided with a second overflow hole 122, which is located downstream of the travel direction of the second drill bit 210. Specifically, the diameter of the second overflow hole 122 is between 3 and 6 mm, and it is connected to the inner hollow sleeve 120. When grout is delivered into the inner hollow sleeve 120, the grout flows out from the second overflow hole 122. Since the second overflow hole 122 is located in front of the travel direction of the second drill bit 210, the second drill bit 210 will not block the second overflow hole 122. Subsequently, the grouting stone body 500 formed by the grout exiting the second overflow hole 122 encapsulates the second drill bit 210. After the grout solidifies, it acts as a second anchoring point.

[0044] In summary, it can be understood that the arrangement of two overflow holes in this embodiment can form two anchoring points near the two drill bits, which greatly improves the anchoring force of this type of anchor compared with general self-drilling anchors.

[0045] like Figure 2 As shown, specifically, the fixed connector 300 is provided with a through-hole 310 along the axial direction. The fixed connector 300 is threadedly connected to the end of the inner hollow sleeve 120 away from the first drill bit 110 through the through-hole 310. More specifically, the through-hole 310 also has an internal thread, thus the through-hole 310 is threadedly connected to the inner hollow sleeve 120. In addition, the fixed connector 300 is also provided with a threaded groove 320 along the axial direction. The fixed connector 300 is threadedly connected to the end of the outer sleeve 220 away from the second drill bit 210 through the threaded groove 320.

[0046] It is understandable that the specially designed fixing connector 300 can fix two sleeves at the same time. The fixing connector 300 has double-layer threads, which must match the external threads of the inner hollow sleeve 120 and the outer sleeve 220. The inner hollow sleeve 120 and the outer sleeve 220 are connected together with the fixing connector 300 through the threads. When using the double-head anti-shear self-rotating anchor provided in this embodiment, the inner hollow sleeve and the outer sleeve 220 are drilled into structures such as mine shafts, adits, tunnels, water conservancy and building foundation pits. After the grout flows out of the first overflow hole 121 and the second overflow hole 122 and solidifies, the fixing connector 300 can be rotated to apply a pre-tightening force to the inner hollow sleeve 120 and the outer sleeve 220.

[0047] In addition, the dual-drill-bit shear anchor bolt provided in this embodiment also includes a tray 400, which is connected to the outer sleeve 220 and close to the fixing connector 300. Specifically, the tray 400 can be threaded onto the outer sleeve 220 or simply fitted onto the outer sleeve 220; either method is acceptable.

[0048] Understandably, when the fixed connector 300 applies pre-tightening force during rotation, the fixed connector 300 exerts a large pressure on the rock mass or rock wall, and has a small contact area with the rock mass or rock wall. This can easily damage the rock mass or rock wall and reduce the pre-tightening force, affecting the overall anchoring force of the anchor bolt. Therefore, a tray 400 is designed to transfer the pressure of the fixed connector 300 on the rock mass or rock wall to the tray 400. Since the tray 400 has a large contact area with the rock mass or rock wall, the pressure per unit area of ​​the rock mass or rock wall is reduced, so the rock mass or rock wall will not be damaged, and the pre-tightening force and anchoring force will not be affected.

[0049] This embodiment also provides a method for using a double-drill-bit shear anchor bolt, as detailed below:

[0050] 1. The double-drill-bit anti-shear self-drilling anchor rod is pushed into the designed position in the rock and soil using a pneumatic drilling rig. Grouting is performed on the exposed end of the anchor rod (with an internal hollow sleeve of 120) using a grouting machine. The water-cement ratio of the grout is 0.45 to 0.5:1, and the final grouting pressure is controlled at 2 MPa. Then, the exposed end of the anchor rod is plugged with a grout stop plug.

[0051] 2. After the grouting stone body 500 reaches a certain strength, a torque wrench is used to rotate the specially designed fixing connector 300 to apply pre-tightening force to the inner hollow sleeve 120 and the outer sleeve 220, connecting the tray 400, the inner hollow sleeve 120, the outer sleeve 220, and the concrete well cylinder 600 together. Simultaneously, the anchor rod, located inside the rock and soil mass, has two anchoring points, significantly increasing the anchoring force and the active reinforcement axial force on the concrete well cylinder 600. Furthermore, due to the two-layer sleeve structure of the inner hollow sleeve 120 and the outer sleeve 220 near the concrete well cylinder 600, the cross-sectional area of ​​the anchor rod body inside the concrete well cylinder 600 is increased, significantly improving the lateral shear resistance of the anchor rod body.

[0052] The dual-drill-bit shear anchor bolt provided in this embodiment has the following advantages:

[0053] The structure of this embodiment is reasonably designed. The two drill bits can achieve one-time drilling of the same anchor rod with different cross-sections, which improves construction efficiency. The dual drill bits are suitable for rapid drilling under complex soil and rock conditions. The outer sleeve 220 and the second drill bit 210 can be separately connected to the inner hollow sleeve 120. The length and diameter of the outer sleeve 220 can be determined on-site according to the needs of use and then assembled on-site, thereby improving the flexibility of this type of anchor rod and improving the local cross-sectional shear strength of the anchor rod. The specially designed fixing connector 300 effectively solves the connection and pre-tightening force application problem between the inner hollow sleeve 120 and the outer sleeve 220, realizing a firm connection between the two and being able to apply pre-tightening force to both at the same time. The arrangement of the dual overflow holes can form two anchoring points near the two drill bits, which greatly improves the anchoring force of the dual-drill-bit shear anchor rod provided in this embodiment compared with general self-drilling anchor rods.

[0054] Second Embodiment

[0055] This embodiment provides a double-drill-bit shear anchor bolt, which is largely the same as the double-drill-bit shear anchor bolt of the first embodiment. The difference between the two lies in the fixing connector 300 and the tray 400 in this embodiment.

[0056] In the dual-drill-bit anti-shear anchor provided in this embodiment, the fixing connector 300 and the tray 400 are manufactured by welding or integral molding process.

[0057] 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 double-drill-bit shear anchor bolt, characterized in that, include: First drill bit assembly; A second drill bit assembly is fitted onto the first drill bit assembly, and the first drill bit assembly and the second drill bit assembly travel in the same direction. A fixing connector, which is sleeved on the first drill bit assembly and connected to one end of the second drill bit assembly; The first drill bit assembly includes a first drill bit and an inner hollow sleeve. The outer wall of the inner hollow sleeve is provided with a first thread, and the first drill bit is threadedly connected to one end of the inner hollow sleeve. The second drill bit assembly includes a second drill bit and an outer sleeve. The outer sleeve has a central hole that extends axially through it. The outer sleeve is threaded to the inner hollow sleeve through the central hole. The outer sleeve has a second thread on its outer wall. The second drill bit is fitted onto the inner hollow sleeve and threaded to one end of the outer sleeve. The first drill bit and the second drill bit are located on the same side. The internal hollow sleeve is provided with a second overflow hole, which is located downstream of the travel direction of the second drill bit; The fixed connector is provided with a connecting hole that extends axially, and the fixed connector is threadedly connected to the end of the inner hollow sleeve away from the first drill bit through the connecting hole. The fixed connector is also provided with a threaded groove that is opened along the axial direction. The fixed connector is threaded to the end of the outer sleeve away from the second drill bit through the threaded groove.

2. The double-drill-bit shear anchor bolt according to claim 1, characterized in that, The first drill bit is provided with a first overflow hole.

3. The double-drill-bit shear anchor bolt according to claim 1, characterized in that, The diameter of the second drill bit is larger than the diameter of the outer casing.

4. A double-drill-bit shear anchor bolt according to claim 1, characterized in that, The internal hollow casing is provided with a second overflow hole, which is located downstream of the second drill bit in the direction of travel.

5. A double-drill-bit shear anchor bolt according to claim 1, characterized in that, The dual-drill-bit shear anchor also includes a tray, which is connected to the outer casing and close to the fixing connector.

6. A reinforcement system, characterized in that, Includes a double-drill-bit shear anchor bolt as described in any one of claims 1 to 5.

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