Chamfer drilling reinforced roadway prestress anchoring support method and drilling equipment

Abstract

The invention discloses a chamfering, drilling and reinforcing roadway prestress anchoring supporting method and drilling equipment, and belongs to the technical field of mining engineering supporting. According to the method, firstly, punching and point drilling are carried out on the periphery of a roadway needing to be designed, secondly, a chamfer-shaped hole drilled through a chamfer drilling mechanism is filled with an expansion material, and after being filled, the expansion material is solidified to form a chamfer drilling shape; the chamfer shape can disperse most tensile force into the broken surrounding rock when the broken surrounding rock is extruded and the shape formed by the expansion material is subjected to the tensile force, so that the broken surrounding rock is extruded and is firmer, and the anchoring force is further enhanced; and finally, reaming, anchoring, laying an anchor net, spraying slurry and the like are conducted, surrounding rock around the roadway is wrapped on one hand, the broken surrounding rock is extruded on the other hand, a stable arch type bearing structure is formed on the surrounding rock, and the bearing capacity of the surrounding rock is fully mobilized.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering support technology, and more specifically, it relates to a method and drilling equipment for prestressed anchoring support of roadways reinforced by chamfered drilling. Background Technology

[0002] In recent years, the geological environment faced by coal mines has become increasingly complex, significantly increasing the difficulty of roadway support. This is especially true in roadways with soft, fractured surrounding rock affected by geological stress and disturbances from nearby engineering projects, where severe roof and floor deformation and obvious mine pressure manifestations frequently occur. This not only reduces coal mine production efficiency but also significantly increases support costs, exacerbates safety hazards, and makes the working environment more dangerous. The entire industry urgently needs in-depth research into technological innovation and support design to improve coal mine safety and production efficiency.

[0003] At present, scholars at home and abroad have conducted a lot of research and experiments on the support problem of soft and broken surrounding rock roadways. Using traditional support methods, there are no hard rock layers in the coal seam occurrence area, and the rock layers themselves are difficult to form a load-bearing structure. Strong expansion and deformation can easily lead to the loss of anchor bolt prestress. Anchor support is difficult to form a stable and effective load-bearing structure. Not only does it require repeated repairs, resulting in high support costs, but the support effect is also unsatisfactory. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a method and drilling equipment for prestressed anchoring support of roadways using chamfered drilling.

[0005] To solve the above-mentioned technical problems, the present invention first provides a method for prestressed anchoring support of roadways reinforced by chamfered drilling, comprising the following steps: S1. Erect temporary support equipment in the top and bottom slabs of the roadway to ensure that there is a safe space for construction at the working face; S2. Use drilling equipment to drill normally on both sides and the roof of the roadway first. When the drill bit enters the roadway as a whole, start chamfering drilling. The drilling sequence is from the bottom of both sides to the top of the roof. S3. After the chamfered hole is completed, fill the chamfered hole with a filler material that can solidify and expand to ensure the stability of the hole; S4. Place the mold before the expansion material is solidified, and after the expansion material is solidified, drill holes and insert the anchor bolt support equipment. S5. After the anchor bolts are driven in, lay the anchor bolts and anchor mesh support auxiliary equipment, and spray concrete on the anchor mesh to complete the roadway support. S6. Refer to steps S2-S5 to anchor and support the tunnel floor.

[0006] Preferably, in step S2, the inner diameter of the hole drilled by the drilling equipment is 10-20cm, the depth is 3-5m, and the radius of the chamfered hole is 10-20cm.

[0007] Preferably, in step S4, the anchor bolt support device is equipped with an anchor bolt mold, and the outer diameter of the anchor bolt mold is smaller than the inner diameter of the drilled hole.

[0008] Preferably, the outer diameter of the anchor bolt is larger than the outer diameter of the anchor bolt mold.

[0009] Preferably, the material of the anchor bolt mold is PVE.

[0010] Preferably, in step S5, the sprayed concrete slurry is concrete with a strength of C25-C30.

[0011] Furthermore, the present invention also provides a chamfered drilling reinforcement tunnel prestressed anchoring drilling device, characterized in that it utilizes the above-mentioned support method, the drilling device includes a drill bit body and a chamfered drilling mechanism disposed in the drill bit body, a drilling power mechanism is connected to the drill bit body, the drilling power mechanism drives the drill bit body to move, and the chamfered drilling mechanism includes an axial buffer part and a radial telescopic adjustment drilling part.

[0012] Preferably, the axial buffer portion includes a first buffer portion and a second buffer portion, the first buffer portion and the second buffer portion are arranged along the axial direction of the drill bit body, and the second buffer portion is arranged at the end of the first buffer portion; The first buffer section includes a buffer column that can extend and retract along the axial direction of the drill bit body. The second buffer section includes a shock-absorbing buffer spring column that moves in the same direction as the buffer column.

[0013] Preferably, the radial telescopic adjustment drilling section is arranged perpendicularly to the drill bit body, and the radial telescopic adjustment drilling section can move in and out radially along the drill bit body. The radial telescopic adjustment drilling section includes a chamfering drilling mechanism and a telescopic drive section that drives the chamfering drilling mechanism to move in and out radially.

[0014] Preferably, there are two radial telescopic adjustment drilling parts, which are arranged opposite each other along the radial direction of the drill bit body. The chamfering drilling mechanism includes a chamfering drill bit, and the telescopic drive part is connected to the chamfering drill bit. The telescopic drive part includes a hydraulic telescopic block, a chamfering drilling hydraulic telescopic column, and a shear-resistant telescopic spring assembly.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method and drilling equipment for prestressed anchoring support of roadways reinforced by chamfered drilling. The support method consists of three parts: a chamfered drilling mechanism, a chamfered drilling expansion shape, and anchor bolt fixing support. The three parts are interconnected, continuously strengthening the anchor bolt support and the anchor bolt pull-out resistance. First, by drilling around the required tunnel, the chamfering drilling mechanism does not affect the shape of other holes while drilling. Second, the chamfered holes drilled by the chamfering drilling mechanism are filled with expanding material. After the expanding material solidifies, it forms the chamfered hole shape. This shape is very different from the conventional cylindrical shape. The chamfer shape can distribute most of the tensile force to the crushed surrounding rock while compressing and breaking the surrounding rock, making the crushed surrounding rock more solid and further strengthening the anchoring force. Finally, hole enlargement, anchoring, laying anchor mesh, and spraying grouting, on the one hand, wrap the surrounding rock around the tunnel, and on the other hand, compress the crushed surrounding rock to form a stable arch-shaped load-bearing structure in the surrounding rock, fully mobilizing the load-bearing capacity of the surrounding rock itself. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a rendering of the drilling process of a drilling device according to one embodiment of the present invention. Figure 1 ; Figure 2 This is a rendering of the drilling process of a drilling device according to one embodiment of the present invention. Figure 2 ; Figure 3 This is a rendering of the drilling process of a drilling device according to one embodiment of the present invention. Figure 3 ; Figure 4 This is a rendering of the drilling process of a drilling device according to one embodiment of the present invention. Figure 4 ; Figure 5 This is a schematic diagram of the first chamfered hole drilled by the drill bit according to one embodiment of the present invention; Figure 6 This is a schematic diagram of a drill bit with secondary chamfering drilling according to one embodiment of the present invention; Figure 7 This is a schematic diagram of the hole filling shape after drilling is completed according to one embodiment of the present invention; Figure 8This is a three-dimensional structural diagram of a drilling device according to one embodiment of the present invention; Figure 9 This is a schematic diagram of the chamfering drilling mechanism according to one embodiment of the present invention. Figure 1 ; Figure 10 This is a schematic diagram of the structure of one embodiment of the chamfering drilling mechanism of the present invention. Figure 2 ; Figure 11 This is a schematic diagram of the internal structure of a drilling device according to one embodiment of the present invention; Figure 12 This is a schematic diagram of the drilling equipment in one embodiment of the present invention.

[0018] Explanation of symbols in the diagram: 1. Drill bit body; 2. Chamfered drilling mechanism; 3. Drill bit head interface; 4. Buffer column; 5. Chamfered drilling hydraulic telescopic block; 6. Chamfered drill bit; 7. Water supply pipeline; 8. Shear-resistant telescopic spring assembly; 9. Chamfered drilling hydraulic telescopic column; 10. Shock-absorbing buffer spring column; 11. Drilling power equipment; 12. Initial drilling shape; 13. Secondary drilling shape; 14. Complete drilling shape. Detailed Implementation

[0019] To make the technical problems, solutions, and beneficial effects of this application clearer, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a method for prestressed anchoring support of roadways using chamfered drilling and drilling equipment. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] Example 1 This invention provides a method for prestressed anchoring support of roadways reinforced by chamfered drilling, comprising the following steps: S1. Erect temporary support equipment in the top and bottom slabs of the roadway to ensure that there is a safe space for construction at the working face; S2. Use drilling equipment to drill normally on both sides and the roof of the roadway first. When the drill bit enters the roadway as a whole, start chamfering drilling. The drilling sequence is from the bottom of both sides to the top of the roof. S3. After the chamfered hole is completed, fill the chamfered hole with a filler material that can solidify and expand to ensure the stability of the hole; S4. Place the mold before the expansion material is solidified, and after the expansion material is solidified, drill holes and insert the anchor bolt support equipment. S5. After the anchor bolts are driven in, lay the anchor bolts and anchor mesh support auxiliary equipment, and spray concrete on the anchor mesh to complete the roadway support. S6. Refer to steps S2-S5 to anchor and support the tunnel floor.

[0021] The support method provided in this invention consists of three parts: a chamfered drilling mechanism, a chamfered drilling expansion shape, and anchor bolt fixing support. These three parts are interconnected, continuously strengthening the anchor bolt support and its pull-out resistance. First, drilling points are selected around the designed roadway. The chamfered drilling mechanism does not affect other drilled shapes during drilling. Second, the chamfered holes drilled by the chamfered drilling mechanism are filled with expansion material. After the expansion material solidifies, it forms the chamfered hole shape. This shape differs significantly from the conventional cylindrical shape. The chamfered shape allows the expansion material to distribute most of the tensile force to the fractured surrounding rock while compressing and breaking it, making the fractured surrounding rock more robust and further strengthening the anchoring force. Finally, hole enlargement, anchor installation, anchor mesh laying, and grout spraying encase the surrounding rock around the roadway while simultaneously compressing the fractured surrounding rock, forming a stable arch-shaped load-bearing structure and fully mobilizing the rock's own load-bearing capacity.

[0022] Example 2 This invention provides a method for prestressed anchoring support of roadways reinforced by chamfered drilling, such as... Figures 1-4 As shown, the specific steps include: S1. Temporary support frames are erected in the top and bottom slabs of the roadway to ensure safety and sufficient space for construction within the working face.

[0023] S2. The drilling equipment provided by this invention is used to drill normally on both sides and the roof of the roadway. When the drill bit enters the roadway as a whole, chamfering drilling begins. The drilling sequence is from the bottom of both sides to the top of the roof. In this embodiment, the inner diameter of the hole drilled by the drilling equipment is 10-20cm, the depth is 3-5m, and the radius of the chamfered hole is 10-20cm. At the same time, the parameters of the chamfering equipment can be adjusted according to the actual construction needs.

[0024] S3. After the chamfered hole is completed, fill the chamfered hole with a filler material that can solidify and expand to ensure the stability of the hole, so that the next step can be carried out stably.

[0025] S4. Place the mold before the expansion material is solidified, and after the expansion material solidifies, drill holes and insert the anchor bolt support equipment.

[0026] In this embodiment, the chamfering drilling mechanism drills a hole larger than the commonly used hole size. The anchor bolt support equipment is equipped with an anchor bolt mold. The outer diameter of the anchor bolt mold is smaller than the inner diameter of the drilled hole, and the outer diameter of the anchor bolt is larger than the outer diameter of the anchor bolt mold.

[0027] Furthermore, the anchor bolt mold is made of PVE material.

[0028] S5. After the anchor bolts are driven in, lay the anchor bolts and anchor mesh support auxiliary equipment, and spray concrete on the anchor mesh to complete the roadway support.

[0029] The support auxiliary equipment used in this embodiment includes conventional auxiliary facilities such as anchor nets, trays, and nuts, which can also be adjusted and adapted according to support requirements.

[0030] Furthermore, in this embodiment, the sprayed concrete slurry is C25-C30 strength concrete.

[0031] S6. Refer to steps S2-S5 to anchor and support the tunnel floor.

[0032] Example 3 This invention provides a method for prestressed anchoring support of roadways reinforced by chamfered drilling, specifically including the following steps: S1. First, tunnel excavation is carried out. After the excavation is completed, a steel frame is erected in the tunnel for temporary tunnel support to ensure the safety of subsequent construction and the working space for anchoring support.

[0033] S2. Drill holes in the sides and roof of the tunnel.

[0034] like Figures 1-4 As shown, when the drill bit body of the drilling equipment is pushed in to drill, the drilling sequence gradually moves from the bottom of both sides upwards to the top of the top plate. The inner diameter of the drilled hole is 10-20cm, the enlargement radius is 10-20cm, the depth is 3-5m, the hole spacing is 800mm-1200mm, and the hole row spacing is 2500mm-3000mm.

[0035] S3. The drill bit body is driven into the broken surrounding rock by the drilling power equipment. At the same time, the drill bit body is cooled and dust is reduced by water supply through the water pipe to ensure that the drill bit can work normally. After the drill bit body enters the hole, the chamfered drill bit is started. The chamfered drill bit starts to rotate and slowly opens outward, aligning with the rotation of the drill bit body to form a chamfered hole.

[0036] like Figures 5-7 As shown in the figure, 12 is the shape of the first borehole (partial display), 13 is the shape of the second borehole (partial display), and 14 is the complete borehole shape.

[0037] Once the drill bit reaches the designated position, such as Figure 5 As shown, the drill bit rotates at an angle of 30°, which is the maximum rotation angle for the first drilling, completing the first chamfered drilling and forming the shape of the first drilled hole (partially shown) 12.

[0038] S4. After completing the first chamfering and drilling, the drill bit body is pulled outward a certain distance by the drilling power equipment and then continues to advance into the hole. At this time, the rotation angle of the chamfering drill bit is 70°, which is the maximum rotation angle for the second drilling. Figure 6 As shown, as the equipment moves forward, it completes the chamfering drilling, forming the secondary drilling shape (partially shown) 13.

[0039] S5. Complete the drilling step, remove the equipment to form the final complete drilled hole shape 14, as shown. Figure 7 As shown, the tunnel is supported by steps such as filling, drilling, anchoring, and laying anchor mesh. Steps S1-S5 complete the support of the entire tunnel.

[0040] The unique chamfered structure design provided by this invention enables the anchoring system to have both radial compression and tangential constraint functions. This not only strengthens the integrity of the fractured surrounding rock but also enables effective load transfer when under stress, thereby forming a stable arch-shaped bearing structure. It achieves an organic combination of "equipment-process-structure", improves the pull-out resistance of the anchor bolt, and fully utilizes the self-supporting function of the surrounding rock.

[0041] Example 4 This invention provides a chamfered drilling reinforcement prestressed anchoring drilling device for roadways, which utilizes the aforementioned support method for drilling construction, such as... Figures 8-10 As shown, the drilling equipment includes a drill bit body 1 and a chamfering drilling mechanism 2 disposed inside the drill bit body 1. A drilling power mechanism is connected to the drill bit body 1. The drilling power mechanism drives the drill bit body to move. The lateral drill bit power comes from an external power supply. Drilling can be performed when the rated voltage is reached. The chamfering drilling mechanism includes an axial buffer part and a radial telescopic adjustment drilling part.

[0042] In this embodiment, the end of the drill bit body 1 is provided with a drill bit title interface 3, which enables the drill bit to be connected to other components through the connection port.

[0043] Specifically, such as Figure 11 As shown, the axial buffer section includes a first buffer section and a second buffer section. The first buffer section and the second buffer section are arranged along the axial direction of the drill bit body 1, and the second buffer section is located at the end of the first buffer section. The first buffer section includes a buffer column 4, which can extend and retract along the axial direction of the drill bit body 1. The second buffer section includes a shock-absorbing buffer spring column 10, which moves in the same direction as the buffer column 4.

[0044] Furthermore, in this embodiment, as Figure 12 As shown, the drilling power mechanism is the drilling power device 11, which drives the drill bit body to drill into the broken surrounding rock. The drilling power mechanism can be an electric drilling machine or a hydraulic motor.

[0045] like Figure 11 As shown, the drilling equipment is also equipped with a water supply pipe 7, which is located inside the buffer column 4. When drilling, the water supply pipe 7 is used to reduce dust and cool the left end of the drill bit body to ensure that the drill bit body 1 can work normally.

[0046] Furthermore, the radial telescopic adjustment drilling section is arranged perpendicularly to the drill bit body 1, and the radial telescopic adjustment drilling section can move in and out radially along the drill bit body 1. The radial telescopic adjustment drilling section includes a chamfering drilling mechanism and a telescopic drive section that drives the chamfering drilling mechanism to move in and out radially.

[0047] In this embodiment, there are two radial telescopic adjustment drilling parts, which are respectively arranged opposite to each other along the radial direction of the drill bit body 1. The chamfering drilling mechanism includes a chamfering drill bit 6. The telescopic drive part is connected to the chamfering drill bit 6. The telescopic drive part includes a chamfering drilling hydraulic telescopic block 5, a chamfering drilling hydraulic telescopic column 9, and a shear-resistant telescopic spring group 8.

[0048] Furthermore, in this embodiment, the drilling equipment can be divided into four core systems: a power drive system, an axial buffer and vibration reduction system, a water pipeline dust reduction and cooling system, and a radial angle adjustment system. Through the coordinated operation of the power drive, buffer and vibration reduction, dust reduction and cooling, and radial angle adjustment of each system, the main borehole is first drilled to lay the foundation, and then the lateral staged borehole is expanded and shaped, ultimately achieving a special borehole shape of "cylinder + large chamfer" that meets the prestressed anchoring requirements of the roadway.

[0049] In this embodiment, the power drive system provides the core power for drilling and adjustment. The power drive system consists of a drilling power mechanism, an external power supply + chamfered drill bit, a telescopic drive unit, and a shear-resistant telescopic spring assembly 8. The drilling power mechanism provides power for the "main drilling" part, driving the drill bit body to cut the rock strata by outputting axial thrust and torque, which is the core power source for forming the "cylindrical foundation hole". The external power supply + chamfered drill bit provides rotational power for "lateral hole reaming". The external power supply provides high-speed rotational electrical energy to the chamfered drill bit, enabling it to cut the hole wall and form a chamfer. The telescopic drive unit (hydraulic telescopic block + hydraulic telescopic column) provides power for the radial extension and retraction of the lateral drill bit. By changing the hydraulic oil pressure, it pushes the chamfered drill bit to extend / retract radially along the drill bit body. The shear-resistant telescopic spring assembly 8, as an elastic auxiliary power structure, can counteract the reaction force of the rock strata during hydraulic extension and retraction, avoiding damage to the lateral drill bit due to rigid impact, while maintaining the stability of the extension and retraction process. It is an "auxiliary protection structure" of the power drive system.

[0050] The axial buffer and vibration reduction system is used to protect equipment and improve drilling accuracy. The axial buffer and vibration reduction system includes a first buffer part (buffer column) and a second buffer part (vibration damping spring column). The first buffer part is a primary buffer structure that is directly connected to the drill bit end and can freely extend and retract along the axial direction of the drill bit body 1. When the drill bit contacts a hard interlayer of rock, the buffer column first absorbs the "initial impact energy" through compression deformation, reducing the impact force transmitted to the rear end of the equipment, which is the "first line of defense" against impact. The second buffer part is a secondary deep buffer structure that is set at the end of the first buffer part and moves in the same direction as the buffer column. The remaining impact force after the first-level buffer is further dissipated by the elastic deformation of the vibration damping spring column, reducing the impact load borne by the drill bit body 1 to a safe range and preventing the drill bit edge from cracking or the drilling axis from shifting, which is the "second line of defense" against impact.

[0051] The water pipeline dust suppression and cooling system is used to ensure the continuous operation of the equipment. It includes water pipeline 7 and connection to an external water source. Water pipeline 7 directly applies high-pressure water flow to the friction surface between the drill bit and the rock formation, and simultaneously achieves the two functions of "removing heat (cooling)" and "mixing rock dust (dust suppression)". The external water source ensures a continuous supply of water.

[0052] The radial angle adjustment system achieves "graded chamfering." The system includes a radial telescopic adjustment drill section, an angle limiting structure, and a shear-resistant telescopic spring assembly 8. The radial telescopic adjustment drill section is the basic actuation structure for angle adjustment; two sections are arranged radially opposite each other along the drill bit body 1, perpendicular to the drill bit body 1, and can extend and retract radially. The angle limiting structure is a precise angle control structure used to lock the chamfering angle at different stages, preventing angle deviations that could lead to uneven chamfering. The shear-resistant telescopic spring assembly is a stabilizing structure for angle adjustment. When adjusting the angle laterally, it uses elastic deformation to counteract the reaction force of the rock strata on the drill bit, ensuring a smooth angle adjustment process and stable drill bit posture, preventing angle deviation due to reaction forces. Thus, this embodiment achieves precise control of "graded chamfering" through the cooperation of these three components: providing adjustment space through telescopic extension, controlling the angle range through limiting, and maintaining adjustment stability through springs.

[0053] Furthermore, as a preferred embodiment, the drilling equipment implementation steps are as follows: specifically, three steps: drilling with the drill bit body, first reaming with the side drill bit, and second reaming with the side drill bit.

[0054] Step 1: Drilling the main body of the drill bit: Laying the foundation hole for the "cylindrical" shape. The drill bit is used to drill into the rock, and the impact is reduced by the axial buffer. In this embodiment, the axial buffer includes a first buffer and a second buffer. The first buffer is connected to the end of the drill bit and performs the first buffer cut. The second buffer is arranged along the axial direction of the drill bit body and is located at the end of the first buffer. After the drill bit body is fully inserted, the drilling speed is reduced, and the first step is completed.

[0055] The specific drilling actions include starting the drilling power mechanism, pushing the drill bit body axially towards the fractured surrounding rock, the axial buffer system working synchronously, and reducing the rotation speed after drilling is completed.

[0056] In this embodiment, the power mechanism outputs axial thrust and torque, causing the cutting edge of the drill bit body to cut the rock layer and form an initial "cylindrical blind hole" (the hole depth is set according to the anchoring requirements). During the drilling process, if hard points or interlayers are encountered in the rock layer, the buffer column of the first buffer part is compressed first, and the shock-absorbing spring column of the second buffer part is buffered again to ensure that the drill bit body always advances along the preset axis and avoids "hole deviation". The water pipeline sprays water throughout the process to reduce dust and cool down in real time, preventing the drill bit from overheating and causing a decrease in cutting efficiency.

[0057] Once the drill bit body has fully penetrated the rock formation (reaching the preset hole depth), the drilling power mechanism reduces its rotation speed to prepare for subsequent lateral reaming. Low-speed rotation avoids "cutting interference" between the main drill bit and the extended lateral drill bit when the main drill bit rotates at high speed.

[0058] Step 2: Ream the hole once with a side drill bit: forming a "preliminary small chamfer". After the main drill bit completes the drilling process, the lateral drill bit gradually expands outward, with the angle increasing from 0° to 30° (the first maximum rotation angle). As the main drill bit rotates, the lateral drilling continues to advance, forming a chamfered shape. When the lateral drill bit reaches the first maximum rotation angle, it continues to penetrate deeper into the rock wall, laying the foundation for secondary reaming.

[0059] The specific drilling actions include low-speed rotation of the main drill bit, hydraulic telescopic column pushing the lateral drill bit to extend radially, energizing and rotating the lateral drill bit with the angle increasing from 0° to 30°, small-scale feed of the main drill bit, and completion of the initial chamfering.

[0060] In this embodiment, the lateral drill bit extends radially along the main body under hydraulic drive until its cutting edge contacts the hole wall (at which point the angle is 0°, i.e., the lateral drill bit is perpendicular to the main borehole axis); an external power supply powers the lateral drill bit, causing it to rotate at high speed; as the main drill bit rotates at low speed, the lateral drill bit cuts along the hole wall, while the angle slowly increases from 0° to 30° through a limiting structure, forming a "ring-shaped small chamfer" around the main borehole; when the lateral drill bit reaches 30°, the main drill bit continues to feed slightly into the rock strata, the purpose of which is to reserve a complete "cylindrical hole segment" below the "small chamfer" to provide space for the "chamfer connection" of the secondary borehole expansion, and to avoid "broken corner" during the two expansions.

[0061] Step 3: Secondary reaming with a side drill: forming the "final large chamfer". After the drill bit penetrates a certain distance, the hole is formed into a "cylinder + chamfer". The drill bit is pulled back until the lateral drill bit rotates to the first maximum rotation angle. Then it continues to advance slowly forward. While advancing, the rotation angle of the lateral drill bit gradually rotates from 30° to 70°, cutting the "cylinder" part of the hole formation and connecting it with the chamfer of the hole to form a larger chamfer, finally obtaining the final shape of the chamfered drill hole.

[0062] The specific drilling actions include pulling the main drill bit backward, raising the angle of the side drill bit from 30° to 70°, slowly feeding the main drill bit, cutting the reserved cylindrical section with the side drill bit, and completing the "cylinder + large chamfer" forming.

[0063] In this embodiment, the main drill bit is pulled backward by the reverse drive of the drilling power mechanism to the position where the lateral drill bit first reaches 30° (i.e., the top of the reserved cylindrical section). At this time, the lateral drill bit still maintains contact with the hole wall. The hydraulic system of the telescopic drive adjusts the pressure to slowly increase the angle of the lateral drill bit from 30° to 70° (the second maximum rotation angle). At the same time, the shear extension spring group deforms synchronously to maintain the stable cutting posture of the lateral drill bit. The main drill bit feeds forward slowly at a very low speed, and the lateral drill bit cuts the reserved cylindrical section under high-speed rotation, seamlessly connecting the "small chamfer" of the first hole enlargement with the "new chamfer" of the second cut, ultimately forming a special drilling shape with "cylinder bottom and 70° large chamfer top". After the hole enlargement is completed, the hydraulic telescopic column pulls the lateral drill bit back into the main body, the drilling power mechanism stops working, and the water pipe continues to spray water for a moment (to clean the residual rock debris in the hole), finally completing the entire drilling operation.

[0064] This invention provides a prestressed anchoring support method and drilling equipment for reinforcing soft rock roadways using chamfered drilling. It consists of three parts: a chamfered drilling mechanism, a chamfered drilling expansion shape, and anchor bolt fixing support. These three parts are interconnected, continuously strengthening the anchor bolt support and its pull-out resistance. The invention first drills a hole using the main drill bit, utilizing a buffer structure to reduce impact, and then reduces the rotation speed. Next, a lateral drill bit is used to enlarge the hole for the first time, with the angle increasing from 0° to 30°, forming a preliminary chamfer. Finally, a lateral drill bit is used to enlarge the hole a second time, with the angle increasing from 30° to 70°, forming a larger connecting chamfer, ultimately completing the "cylinder + large chamfer" hole shape. The drilling equipment, through step-by-step drilling and an adjustable-angle lateral drill bit design, can form anchoring holes of specific shapes in roadway reinforcement, improving the anchoring effect. By optimizing the hole structure and enhancing the synergistic effect between the surrounding rock and the anchoring, it significantly improves the support stability of soft rock roadways.

[0065] This invention first involves drilling points around the desired tunnel design, with a chamfered drilling mechanism that does not affect other drilled holes during drilling. Secondly, the chamfered holes drilled by this invention are filled with an expanding material. After solidification, the expanding material forms a chamfered hole shape, significantly different from conventional cylindrical filling. Traditional cylindrical filling relies on compressing and breaking the surrounding rock to create a unified structure. When the compressive force between the filling material and the surrounding rock decreases, the anchoring force within the filling material also decreases. The chamfered shape, however, allows the expanding material to distribute most of the tensile force within the broken rock while compressing it, making the rock more robust and further strengthening the anchoring force. Finally, the process involves enlarging the holes, anchoring, laying anchor mesh, placing pallet nuts, and spraying grout. This process wraps the surrounding rock around the tunnel while simultaneously compressing it, forming a stable arched load-bearing structure that fully utilizes the rock's own load-bearing capacity.

[0066] Furthermore, this invention employs a chamfered drilling mechanism to drill holes of a specific shape in the surrounding rock. After filling with material, a chamfered anchoring structure is formed. Compared to traditional cylindrical anchor holes, this structure can more effectively disperse the anchor bolt tension to the surrounding rock, avoiding anchoring failure caused by stress concentration. During construction, the drilling points are first precisely located, and chamfered holes are formed using specialized equipment. Then, filling material is injected, and after solidification, a mechanically advantageous irregular-shaped anchoring foundation is formed. A complete support system is then constructed through processes such as installing anchor bolts, laying anchor mesh, and spraying grout. This invention ensures the efficiency of the main drilling through a drilling power mechanism, achieves radial / angle adjustment of the lateral drill bit through hydraulic drive, mitigates rock impact through two-stage buffering, and ensures equipment life and operational safety through water pipelines. Finally, following a step-by-step logic of "main body first, then small chamfer, and finally large chamfer," a borehole that meets the prestressed anchoring requirements of the tunnel is formed. The large chamfer structure increases the contact area between the anchoring agent and the hole wall, enhances the anchoring force, and prevents hole wall collapse during the anchoring process in fractured surrounding rock. The method of this invention achieves an organic combination of "equipment-process-structure", improves the pull-out resistance of anchor bolts, and gives full play to the self-supporting function of surrounding rock.

[0067] In the description of this invention, it should be understood that terms such as “length”, “width”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, and “outer” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for prestressed anchoring support of roadways reinforced by chamfered drilling, characterized in that, Includes the following steps: S1. Erect temporary support equipment in the top and bottom slabs of the roadway to ensure that there is a safe space for construction at the working face; S2. Use drilling equipment to drill normally on both sides and the roof of the roadway first. When the drill bit enters the roadway as a whole, start chamfering drilling. The drilling sequence is from the bottom of both sides to the top of the roof. S3. After the chamfered hole is completed, fill the chamfered hole with a filler material that can solidify and expand to ensure the stability of the hole; S4. Place the mold before the expansion material is solidified, and after the expansion material is solidified, drill holes and insert the anchor bolt support equipment. S5. After the anchor bolts are driven in, lay the anchor bolts and anchor mesh support auxiliary equipment, and spray concrete on the anchor mesh to complete the roadway support. S6. Refer to steps S2-S5 to anchor and support the tunnel floor.

2. The method for prestressed anchoring support of roadways reinforced by chamfered drilling according to claim 1, characterized in that, In step S2, the inner diameter of the hole drilled by the drilling equipment is 10-20cm, the depth is 3-5m, and the radius of the chamfered hole is 10-20cm.

3. The method for prestressed anchoring support of roadways reinforced by chamfered drilling according to claim 1, characterized in that, In step S4, the anchor bolt support equipment is equipped with an anchor bolt mold, the outer diameter of which is smaller than the inner diameter of the drilled hole.

4. The method for prestressed anchoring support of roadways reinforced by chamfered drilling according to claim 3, characterized in that, The outer diameter of the anchor rod is larger than the outer diameter of the anchor rod mold.

5. The method for prestressed anchoring support of roadways reinforced by chamfered drilling according to claim 3, characterized in that, The anchor bolt mold is made of PVE.

6. The method for prestressed anchoring support of roadways reinforced by chamfered drilling according to claim 1, characterized in that, In step S5, the sprayed concrete slurry is C25-C30 strength concrete.

7. A chamfered drilling device for prestressed anchoring drilling in roadways, characterized in that, It utilizes the support method as described in any one of claims 1-6. The drilling equipment includes a drill bit body and a chamfered drilling mechanism disposed within the drill bit body. A drilling power mechanism is connected to the drill bit body, and the drilling power mechanism drives the drill bit body to move. The chamfered drilling mechanism includes an axial buffer portion and a radial telescopic adjustment drilling portion.

8. The chamfered drilling equipment for reinforcing prestressed anchorage in roadways according to claim 7, characterized in that, The axial buffer section includes a first buffer section and a second buffer section, the first buffer section and the second buffer section are arranged along the axial direction of the drill bit body, and the second buffer section is arranged at the end of the first buffer section; The first buffer part includes a buffer column that can extend and retract along the axial direction of the drill bit body. The second buffer part includes a shock-absorbing buffer spring column that moves in the same direction as the buffer column.

9. The chamfered drilling equipment for reinforcing prestressed anchorage in roadways according to claim 7, characterized in that, The radial telescopic adjustment drilling section is arranged perpendicularly to the drill bit body, and the radial telescopic adjustment drilling section can extend and retract along the radial direction of the drill bit body. The radial telescopic adjustment drilling section includes a chamfering drilling mechanism and a telescopic drive section that drives the chamfering drilling mechanism to extend and retract radially.

10. The chamfered drilling equipment for reinforcing prestressed anchorage in roadways according to claim 9, characterized in that, Two radial telescopic adjustment drilling sections are provided, respectively arranged opposite each other along the radial direction of the drill bit body. The chamfering drilling mechanism includes a chamfering drill bit. The telescopic drive section is connected to the chamfering drill bit. The telescopic drive section includes a hydraulic telescopic block, a chamfering drilling hydraulic telescopic column, and a shear-resistant telescopic spring assembly.

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