Anchor hole drilling equipment for easily caving strata and synchronous hole washing and grouting construction method

Abstract

The present invention discloses a hole-forming device for anchor cables in easily caving strata and a synchronous hole-washing and grouting construction method. The hole-forming device for anchor cables in easily caving strata is composed of an alloy drill bit, a drill pipe, a conversion section, a conversion chamber joint, a prestressed anchor cable, an anchor plate, a centering bracket, a water injection pipe, and a grouting pipe. The synchronous hole-washing and grouting construction method for anchor cables in easily caving strata includes eight construction steps: pilot hole drilling, drill pipe installation, connection of the conversion chamber joint, prestressed anchor cable installation, water injection-assisted cutting of the anchor hole, hole-forming detection and cleaning, pulling out the drill pipe while performing synchronous high-pressure grouting and water injection, and prestress tensioning of the anchor cable. By using a hollow drill pipe to carry the anchor cable for water injection cutting drilling, a stable retaining wall can be formed, reducing accidents such as caving and sticking of the drill. The internal space of the drill pipe serves as a slag suction channel, and a grouting pipe and a water injection pipe are provided to perform grouting and hole-washing operations synchronously at the bottom of the borehole, greatly reducing the construction period. Moreover, the mud and slag at the bottom of the borehole are synchronously removed by negative pressure, solving the problem of incomplete hole cleaning in drilling.

Description

Technical Field

[0001] The present invention relates to the construction of prestressed anchor cables, and particularly to an anchor hole forming device for easily caving strata and a synchronous hole washing and grouting construction method. Background Art

[0002] In the construction of slopes and foundation pits, good results can be obtained by using prestressed anchor cable structures for support. However, it is difficult to form holes in geological conditions with poor geology and complex hydrogeological conditions such as gravel layers, pebble layers, and highly water-saturated soft soil layers. When the drill rod is pulled out after hole formation, the anchor hole is extremely easy to deform or even cave in, seriously affecting the construction efficiency, and it is difficult to ensure the safety of the foundation pit slope. Moreover, traditional prestressed anchor cables have problems such as incomplete hole cleaning and slurry diffusion and penetration in the construction of anchor cables in easily caving strata, resulting in limited bearing capacity of the anchorage section, difficult construction quality assurance, and great potential safety hazards.

[0003] Therefore, it is necessary to optimize and improve the anchor hole forming device and construction method for prestressed anchor cables in easily caving strata. Summary of the Invention

[0004] The purpose of the present invention is to propose an anchor hole forming device for easily caving strata and a synchronous hole washing and grouting construction method in view of the problems existing in the existing prestressed anchor cable construction.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions.

[0006] The hole-forming equipment for anchor cables in easily caving strata consists of an alloy drill bit, drill pipes, a conversion section, a conversion chamber joint, a prestressed anchor cable, an anchor plate, a centering bracket, a water injection pipe, and a grouting pipe. The top of the alloy drill bit is provided with external threads, and a grouting channel is arranged inside. At the top of the grouting channel, there is a grouting pipe connection nozzle. At the bottom end of the grouting channel, a check valve and a high-pressure nozzle are successively arranged. And a circumferential bearing groove A is arranged around the alloy drill bit, and a bearing A is arranged in the bearing groove A. The top of the alloy drill bit is successively connected to the drill pipe, the conversion section, and the conversion chamber joint. The drill pipe includes a slag-suction drill pipe connected to the alloy drill bit and connecting drill pipes that are successively thread-connected at the upper part. The bottom of the drill pipe is provided with internal threads for connection, and the top is provided with external threads for connection. The slag-suction drill pipe is provided with slag-suction holes on its body. A slurry plug is installed in the slag-suction holes, and a water spray nozzle is arranged 20 - 50 cm above the slag-suction holes. The conversion section is arranged between the connecting drill pipe and the conversion chamber joint, and both the upper and lower ends are provided with internal threads. The conversion chamber joint consists of an upper closed cover plate, a fixed joint, a lower rotating joint, and a bottom plate. The inside of the conversion chamber joint is divided into a grouting conversion chamber, a water injection conversion chamber, and a slag-suction conversion chamber by the chamber wall from the inside out. The closed cover plate is provided with a water injection port, a grouting port, and a slag discharge port. The bottom of the fixed joint is provided with a bearing expansion chamber larger than the diameter of the fixed joint. A bearing B and a snap ring are arranged inside the bearing expansion chamber. At the bottom of the three chamber walls inside the fixed joint, there are smooth ends with a semi-circular cross-section. 1 - 3 sealing ring grooves are arranged on the smooth ends, and sealing rings are arranged in the sealing ring grooves. The outer chamber wall of the rotating joint is provided with external threads, and a U-shaped ring groove matching the smooth end is arranged at the top of the chamber wall. Lubricating grease is filled in the sealing space formed by the sealing ring, the smooth end of the chamber wall, and the U-shaped ring groove. A center plate is arranged at the center of the bottom plate, and an outer ring plate is arranged outside. And a connecting rod is arranged between the two for connection. The center plate is provided with a water injection pipe connection nozzle and a grouting pipe connection nozzle. The prestressed anchor cable is arranged around the drill pipe and is fixed on the bearing A of the alloy drill bit through the anchor plate and fixing nuts at the bottom. The anchor plate is provided with a drill pipe hole, and a plurality of anchor cable holes are evenly arranged outside the drill pipe hole. A bearing groove B with the same outer diameter as the bearing is also arranged above the drill pipe hole of the anchor plate. The centering brackets are arranged at intervals on the prestressed anchor cable to integrate multiple steel strands into a whole. The water injection pipe and the grouting pipe are arranged inside the drill pipe. The two ends of the grouting pipe are respectively connected to the grouting pipe connection nozzles on the alloy drill bit and the conversion chamber joint. The two ends of the water injection pipe are respectively connected to the water spray nozzle of the slag-suction drill pipe and the water injection pipe connection nozzle on the conversion chamber joint.

[0007] Preferably, the inner diameter ring of the bearing A is installed inside the bearing groove A of the alloy drill bit, and the outer diameter ring is installed inside the bearing groove B of the anchor plate. The bearing groove A has the same inner diameter as the bearing A, and the bearing groove B has the same outer diameter as the bearing A.

[0008] Preferably, the slurry plug is provided with a wedge-shaped installation port and is arranged inside the slag-suction hole. Before slag suction, it is evacuated from the slag-suction hole by negative pressure.

[0009] Preferably, the internal and external threads involved in the alloy drill bit, drill pipe, conversion section and conversion chamber joint match each other and are connected up and down to form an integral whole.

[0010] Preferably, during the process of drilling the anchor hole, clear water is injected through the grouting port for cutting to assist in hole formation. During the process of pulling out the drill pipe, high-pressure jet grouting of cement slurry is carried out to form a grouting and anchoring section. Clear water is injected through the water injection port to clean the hole during the process of pulling out the drill pipe. During the process of pulling out the drill pipe, the mud and slag mixture in the hole is sucked out under negative pressure through the slag discharge port.

[0011] Preferably, the snap ring is arranged in the snap ring groove of the bearing expansion chamber at the bottom of bearing B to limit bearing B in the bearing expansion chamber. The outer diameter of bearing B is the same as the inner diameter of the bearing expansion chamber, and the inner diameter is the same as the outer diameter of the wall of the rotating joint chamber, so that the rotating joint rotates relative to the fixed joint.

[0012] Preferably, the diameters of the closed cover plate and the bottom plate are the same as the outer diameter of the conversion chamber joint, and they are respectively fixed to the top and bottom of the fixed joint and the rotating joint. The diameter of the central plate on the bottom plate is the same as the diameter of the water injection conversion chamber, and the connecting rod is inside the slag suction conversion chamber.

[0013] Preferably, the cement slurry in the grouting pipe is injected from the grouting port into the conversion chamber joint, transported through the grouting pipe and sprayed out under high pressure from the high-pressure nozzle of the alloy drill bit. The clear water in the water injection pipe is injected from the water injection port into the conversion chamber joint, transported through the water injection pipe and sprayed out from the water spray nozzle of the slag suction drill pipe. The mud and slag mixture of the anchor hole flows in from the slag suction hole of the slag suction drill pipe, flows from the inside of the drill pipe to the conversion chamber joint, and is discharged from the slag discharge port.

[0014] Preferably, the anchor hole forming equipment for the easily caving formation and the synchronous hole washing and grouting construction method include the following steps:

[0015] S1. Pilot hole drilling: Drill a pilot hole with a depth of 1.0 m on the slope surface.

[0016] S2. Drill pipe installation: Assemble the alloy drill bit, slag suction drill pipe, connecting drill pipe, conversion section and conversion chamber joint in sequence. S2.1. Install a slurry plug with the same cross-section as the slag suction hole in the slag suction hole of the slag suction drill pipe. S2.2. Install bearing A and the anchoring plate in the bearing groove A of the alloy drill bit, connect the grouting pipe to the top grouting pipe connection nozzle, and connect the water injection pipe to the water spray nozzle of the slag suction drill pipe. S2.3. Form an integral whole by connecting the slag suction drill pipe and the alloy drill bit through the connecting thread, and install 1 - 2 sections of connecting drill pipes on the slag suction drill pipe. S2.4. Install the conversion section on the top connecting drill pipe.

[0017] S3. Connect the conversion chamber joint: Connect the water injection pipe and the grouting pipe to the water injection pipe connection nozzle and the grouting pipe connection nozzle of the conversion chamber joint respectively to form a pressure channel, and connect the connecting conversion chamber joint to the top of the conversion section through a thread.

[0018] S4. Installation of prestressed anchor cables: Fabricate prestressed anchor cables of the designed length, pass the prestressed anchor cables through the anchor cable holes on the anchor plate, and fix them with fixing nuts.

[0019] S5. Water injection-assisted cutting of anchor holes: S5.1. The drill rig drills in a circulating manner and simultaneously injects high-pressure water through the grouting pipe to cut the hole; S5.2. When all the drill pipes are connected and drilled into the anchor hole, the conversion section is removed by reverse circulation, the grouting pipe and the water injection pipe are lengthened, and at the same time, 1 - 2 sections of connecting drill pipes are added; S5.3. Reconnect the conversion section and continue to inject water to cut the anchor hole; S5.4. Drill in a circulating manner according to the sequence of S5.1 - S5.3 until the designed hole depth is reached.

[0020] S6. Hole formation inspection and cleaning: Detect the depth of the anchor hole through the length of the drill pipe, and continuously inject clean water through the grouting pipe to clean the hole.

[0021] S7. Pull out the drill pipe while performing high-pressure grouting and water injection: S7.1. Apply negative pressure through the slag outlet to pull the slurry plug in the slag suction hole out of the slag suction hole; S7.2. After the hole formation is completed, perform high-pressure rotary jet grouting at the bottom of the hole through the high-pressure nozzle to form an enlarged high-pressure grouting body; S7.3. When grouting, simultaneously inject clean water through the water injection pipe to clean the prestressed anchor cable above the slag suction hole and the anchor hole; continuously apply negative pressure during the construction to suck out the mud and slag mixture at the bottom of the hole; S7.4. Slowly pull out the drill pipe, while performing high-pressure grouting, water injection and slag cleaning until the end of the anchorage section; S7.5. Continue to pull out the drill pipe, while grouting, water injection and slag cleaning until the hole mouth, and the grouting is carried out under normal pressure.

[0022] S8. Tensioning of the prestress of the anchor cable: Install the backing plate and the anchor head on the slope surface and perform staged tensioning. After the tensioning is completed, seal the anchor head.

[0023] The technical solution involved in the present invention has the following beneficial effects compared with the traditional technology:

[0024] 1. The enlarged cement slurry formed by high-pressure rotary jet grouting at the bottom of the prestressed anchor cable changes the stress condition of the anchor cable, greatly improves the anchoring force of the anchor cable, solves the problem of slurry diffusion and penetration, has strong construction adaptability, can still ensure the anchoring force even in soft strata, and at the same time improves the reliability and safety of the anchor cable technology.

[0025] 2. In the formation prone to hole collapse, use a hollow drill pipe to carry the anchor cable for water injection cutting and drilling. The drill pipe and the anchor cable can form a stable retaining wall, reduce accidents such as hole collapse and drill sticking, and improve the construction quality and efficiency.

[0026] 3. The internal space of the hollow drill pipe serves as a slag suction channel, and a grouting pipe and a water injection pipe are provided. During the process of pulling out the drill pipe and grouting, negative pressure is used to remove the mud and slag at the bottom of the drill hole, solving the problem of incomplete hole cleaning.

[0027] 4. When pulling out the drill pipe, grouting and hole washing operations are carried out synchronously at the bottom of the borehole, and as the drill pipe is pulled out, it gradually rises. The traditional steps of pulling out the drill, installing the anchor, washing the hole, and grouting for prestressed anchor cables are synchronized into one step, greatly reducing the construction period.

[0028] 5. A bearing is provided at the bottom end of the hollow drill pipe, and the drill pipe can rotate relative to the surrounding anchor cables. The anchor cables will not get entangled or deformed during the drilling process of the drill pipe, ensuring the installation quality of the anchor cables. Moreover, the drill pipe can be removed and reused later, reducing material losses and construction costs.

[0029] 6. A conversion chamber joint is provided at the top of the hollow drill pipe. The upper fixed joint grouting conversion chamber, water injection conversion chamber, and slag suction conversion chamber are respectively connected to the grouting pipe, water injection pipe, and negative pressure slag suction pipe. The lower rotating joint is connected to the hollow drill pipe and rotates synchronously, and cement slurry and clear water are respectively injected, facilitating the provision of pressure during the cutting, grouting, and hole cleaning stages and solving the problem of entanglement of the pipelines during the rotation of the drill pipe.

[0030] 7. The fixed joint and the wall of the conversion joint chamber are respectively provided with smooth ends and U-shaped ring grooves, and combined with a sealing ring, the sealing effect between the fixed joint and the conversion joint is achieved; the bearing and the smooth end achieve the rotating effect between the fixed joint and the conversion joint; while the fixed joint and the conversion joint rotate relative to each other, the different pressure transmissions of water injection, grouting, and slag suction negative pressure are ensured. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of an anchor cable hole-forming device in easily caving strata;

[0032] Figure 2 is a schematic diagram of synchronous hole washing and grouting for anchor cable hole forming in easily caving strata;

[0033] Figure 3 is a schematic structural diagram after pulling out the drill during the construction of anchor cables in easily caving strata;

[0034] Figure 4 is a schematic structural diagram of the conversion chamber joint;

[0035] Figure 5 is a sectional view of the conversion chamber joint ( Figure 4 section A-A in);;

[0036] Figure 6 is a schematic structural diagram of the fixed joint;

[0037] Figure 7 is a schematic diagram of the connection between the slag suction conversion chamber and the closed cover plate;

[0038] Figure 8 is a schematic diagram of the connection between the water injection conversion chamber and the closed cover plate;

[0039] Figure 9 It is a schematic diagram of the connection between the grouting conversion bin and the closed cover plate;

[0040] Figure 10 It is a schematic diagram of the snap ring structure;

[0041] Figure 11 It is a schematic diagram of the seal ring structure;

[0042] Figure 12 It is a schematic diagram of the rotating joint structure;

[0043] Figure 13 It is a schematic diagram of the bottom plate structure;

[0044] Figure 14 It is a schematic diagram of the connection between the slag suction conversion bin and the bottom plate;

[0045] Figure 15 It is a schematic diagram of the connection between the water injection conversion bin and the bottom plate;

[0046] Figure 16 It is a schematic diagram of the connection between the grouting conversion bin and the bottom plate;

[0047] Figure 17 It is a schematic diagram of the conversion section structure;

[0048] Figure 18 It is a sectional view of the conversion section ( Figure 17 section B-B in the figure);

[0049] Figure 19 It is a schematic diagram of the slag suction drill pipe structure;

[0050] Figure 20 It is a schematic diagram of the connecting drill pipe structure;

[0051] Figure 21 It is a schematic diagram of the slurry plug structure;

[0052] Figure 22 It is a schematic diagram of the alloy drill bit structure;

[0053] Figure 23 It is a schematic diagram of installing the bearing alloy drill bit;

[0054] Figure 24 It is a schematic diagram of the alloy drill bit without the installed bearing;

[0055] Figure 25 It is a schematic diagram of the anchor plate structure;

[0056] Figure 26 It is a sectional view of the anchor plate ( Figure 25 section C-C in the figure);

[0057] Figure 27 It is a schematic diagram of the centering support structure;

[0058] Figure 28 It is the construction flow chart of the synchronous hole washing and grouting construction method for the anchor cable hole forming in the easily caving hole formation.

[0059] Annotations in the figure: 1 - alloy drill bit, 101 - grouting channel, 102 - bearing groove A, 103 - high-pressure nozzle, 104 - check valve, 2 - drill pipe, 201 - slag suction drill pipe, 202 - connecting drill pipe, 203 - slag suction hole, 204 - water spray nozzle, 3 - conversion section, 4 - conversion bin joint, 401 - fixed joint, 402 - rotating joint, 403 - closing cover plate, 404 - bottom plate, 4041 - center plate, 4042 - outer ring plate, 4043 - connecting rod, 405 - bearing expansion bin, 406 - circlip groove, 407 - water injection port, 408 - grouting port, 409 - slag discharge port, 4010 - bin wall, 4011 - smooth end, 4012 - U-shaped ring groove, 4013 - sealing ring groove, 5 - prestressed anchor cable, 6 - bearing, 601 - bearing A, 602 - bearing B, 7 - anchoring plate, 701 - bearing groove B, 702 - drill pipe hole, 703 - anchor cable hole, 8 - connecting thread, 801 - internal thread, 802 - external thread, 9 - anchor hole, 10 - connecting nozzle, 1001 - water injection pipe connecting nozzle, 1002 - grouting pipe connecting nozzle, 11 - circlip, 12 - lubricating grease, 13 - fixing nut, 14 - drill pipe splicing joint, 15 - water injection pipe, 16 - grouting pipe, 17 - cement slurry, 18 - mud and slag mixture, 19 - clear water, 20 - cement slurry flow direction, 21 - high-pressure water flow direction, 22 - slag discharge flow direction, 23 - sealing ring, 24 - centering support, 25 - grout plug. Specific embodiments

[0060] To deepen the understanding of the present invention, the following will refer to Figures 1 to 28 , and make a detailed description of the embodiments of the present invention. The following embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners are given, but the protection scope of the present invention is not limited to the following embodiments.

[0061] In this embodiment, the alloy drill bit 1 has a diameter of 10 cm. The slag suction drill pipe 201 and the connecting drill pipe 202 each have a length of 1 m. The connecting thread 8 has a length of 10 cm. The anchor hole 9 has a diameter of 15 cm and a depth of 20 m. The prestressed anchor cable 5 uses 1860-grade steel strands, and the connection strength of a single steel strand is greater than 200 kN. A centering support 24 is arranged every 2 m along the axial direction. The grouting material uses pure cement slurry 17 with a water-cement ratio of 0.45 - 0.50. The conversion bin joint 4 has a height of 30 cm, among which the fixed joint 401 has a height of 16 cm, the rotating joint 402 has a height of 16 cm, the overlapping height of the smooth end 4011 and the U-shaped ring groove 4012 is 1 cm. The conversion bin joint 4 has a diameter of 20 cm, the bearing expansion bin 405 has a diameter of 25 cm, the grouting conversion bin has a diameter of 5 cm, the water injection conversion bin has a diameter of 10 cm, and the slag suction conversion bin has a diameter of 20 cm.

[0062] Combined with the attached Figure 1 As shown, the anchor hole forming equipment for easily caving strata is composed of an alloy drill bit 1, a drill pipe 2, a conversion section 3, a conversion bin joint 4, a prestressed anchor cable 5, an anchor plate 7, a centering support 24, a water injection pipe 15, and a grouting pipe 16; combined with the attached Figure 22 ~attached Figure 24 As shown, the top of the alloy drill bit 1 is provided with an external thread 802, and the inside is provided with a grouting channel 101. At the top of the grouting channel 101, there is a grouting pipe connection nozzle 1002. At the bottom end of the grouting channel 101, a check valve 104 and a high-pressure nozzle 103 are successively arranged. And a circumferential bearing groove A102 is arranged around the alloy drill bit 1, and a bearing A601 is arranged in the bearing groove A102; the top of the alloy drill bit 1 is successively connected with the drill pipe 2, the conversion section 3, and the conversion bin joint 4; the prestressed anchor cable 5 is arranged around the drill pipe 2 and is fixed on the bearing A601 of the alloy drill bit 1 through the anchor plate 7 and the fixing nut 13 at the bottom; the water injection pipe 15 and the grouting pipe 16 are arranged inside the drill pipe 2. The two ends of the grouting pipe 16 are respectively connected to the grouting pipe connection nozzle 1002 on the alloy drill bit 1 and the conversion bin joint 4, and the two ends of the water injection pipe 15 are respectively connected to the water spray nozzle 204 of the slag suction drill pipe 201 and the water injection pipe connection nozzle 1001 on the conversion bin joint 4. The internal threads 801 and the external threads 802 involved in the alloy drill bit 1, the drill pipe 2, the conversion section 3, and the conversion bin joint 4 are mutually matched and are connected up and down to form a whole.

[0063] Combined with the attached Figure 2As shown, during the drilling process of the anchor hole 9, the grouting port 408 injects clear water 19 for cutting to assist in hole formation. During the extraction process of the drill pipe 2, high-pressure jet grouting of cement slurry 17 is carried out to form a grouting and anchoring section. The water injection port 407 injects clear water 19 for hole cleaning during the extraction process of the drill pipe 2. The slag outlet 409 sucks out the mud and slag mixture 18 in the hole under negative pressure during the extraction process of the drill pipe 2. The cement slurry 17 in the grouting pipe 16 is injected from the grouting port 408 into the conversion chamber joint 4, transported through the grouting pipe 16, and ejected from the high-pressure nozzle 103 of the alloy drill bit 1 at high pressure. The clear water 19 in the water injection pipe 15 is injected from the water injection port 407 into the conversion chamber joint 4, transported through the water injection pipe 15, and ejected from the water spray nozzle 204 of the slag suction drill pipe 201. The mud and slag mixture 18 in the anchor hole 9 flows into the slag suction hole 203 of the slag suction drill pipe 201, flows from the inside of the drill pipe 2 towards the conversion chamber joint 4, and is discharged from the slag outlet 409.

[0064] Combined with the attached Figure 19 and the attached Figure 20 As shown, the drill pipe 2 includes a slag suction drill pipe 201 connected to the alloy drill bit 1 and connecting drill pipes 202 that are sequentially thread-connected and lengthened at the upper part. The bottom of the drill pipe 2 is provided with an internal thread 801 for connection, and the top is provided with an external thread 802 for connection. The slag suction drill pipe 201 is provided with a slag suction hole 203 on its rod body. A slurry plug 25 is installed in the slag suction hole 203, and a water spray nozzle 204 is provided 20 - 50 cm above the slag suction hole 203.

[0065] Combined with the attached Figure 17 and the attached Figure 18 As shown, the conversion section 3 is arranged between the connecting drill pipe 202 and the conversion chamber joint 4, and both the upper and lower ends are provided with internal threads 801.

[0066] Combined with the attached Figure 4 and the attached Figure 5 and the attached Figure 11 As shown, the conversion chamber joint 4 is composed of an upper closed cover plate 403, a fixed joint 401, a lower rotating joint 402, and a bottom plate 404. The inside of the conversion chamber joint 4 is divided into a grouting conversion chamber, a water injection conversion chamber, and a slag suction conversion chamber by the chamber wall 4010 from the inside out. Combined with the attached Figure 6 ~and the attached Figure 9 As shown, the closed cover plate 403 is provided with a water injection port 407, a grouting port 408, and a slag outlet 409. The bottom of the fixed joint 401 is provided with a bearing expansion chamber 405 larger than the diameter of the fixed joint 401. The bearing expansion chamber 405 is internally provided with a bearing B602 and a snap ring 11. The bottom of the three chamber walls 4010 inside the fixed joint 401 are all provided with smooth ends 4011 with a semi-circular cross-section. One to three sealing ring grooves 4013 are provided on the smooth ends 4011, and sealing rings 23 are arranged in the sealing ring grooves 4013.

[0067] Combined with the attached Figure 12 and the attached Figure 14 ~and the attachedFigure 16 As shown in the figure, the outer wall 4010 of the rotating joint 4 is provided with an external thread 802. At the top of the wall 4010, a U-shaped ring groove 4012 matching the smooth end 4011 is provided. The lubricating grease 12 is filled in the sealing space formed by the sealing ring 23, the smooth end 4011 of the wall 4010 and the U-shaped ring groove 4012. The diameters of the closing cover plate 401 and the bottom plate 404 are the same as the outer diameter of the conversion bin joint 4, and they are respectively fixed to the top and bottom of the fixed joint 401 and the rotating joint 402. The diameter of the central plate 4041 on the bottom plate 404 is the same as the diameter of the water injection conversion bin, and the connecting rod 4043 is inside the slag suction conversion bin.

[0068] Combined with the attached Figure 13 As shown in the figure, a central plate 4041 is provided at the center of the bottom plate 404, an outer ring plate 4042 is provided outside, and a connecting rod 4043 is provided between the two for connection. A water injection pipe connecting nozzle 1001 and a grouting pipe connecting nozzle 1002 are provided on the central plate 4041.

[0069] Combined with the attached Figure 25 and the attached Figure 26 As shown in the figure, a drill rod hole 702 is provided on the anchor plate 7, and a plurality of cable anchor holes 703 are evenly arranged outside the drill rod hole 702. A bearing groove B701 with the same outer diameter as the bearing 6 is also provided above the drill rod hole 702 of the anchor plate 7.

[0070] Combined with the attached Figure 27 As shown in the figure, the centering bracket 24 is spaced on the prestressed cable 5 to integrate multiple steel strands into a whole.

[0071] Combined with the attached Figure 22 and the attached Figure 25 and the attached Figure 26 As shown in the figure, the inner diameter ring of the bearing A601 is installed inside the bearing groove A102 of the alloy drill bit 1, and the outer diameter ring is installed inside the bearing groove B701 of the anchor plate 7. The bearing groove A102 has the same inner diameter as the bearing A601, and the bearing groove B701 has the same outer diameter as the bearing A601.

[0072] Combined with the attached Figure 21 As shown in the figure, the slurry plug 25 is provided with a wedge-shaped installation opening and is arranged inside the slag suction hole 203. Before slag suction, it is evacuated from the slag suction hole 203 by negative pressure.

[0073] Combined with the attached Figure 5 and the attached Figure 10 As shown in the figure, the snap ring 11 is arranged in the snap ring groove 406 of the bearing expansion chamber 405 at the bottom of the bearing B602 to limit the bearing B602 in the bearing expansion chamber 405. Then combined with the attached Figure 6 and the attached Figure 12As shown, the outer diameter of bearing B602 is the same as the inner diameter of bearing expansion chamber 405, and the inner diameter is the same as the outer diameter of the wall 4010 of rotating joint 402, so that rotating joint 402 rotates relative to fixed joint 401.

[0074] Combined with the attached drawings Figure 3 、 28 As shown, the construction method of simultaneous hole washing and grouting for cable anchor hole formation in easily caving strata includes the following steps.

[0075] S1. Pilot hole: Drill a pilot hole with a depth of 1.0 m on the slope surface.

[0076] S2. Installation of drill pipe 2: Assemble alloy drill bit 1, slag suction drill pipe 201, connecting drill pipe 202, conversion section 3 and conversion chamber joint 4 in sequence.

[0077] S2.1. Install a slurry plug 25 with the same cross-section as slag suction hole 203 in slag suction hole 203 of slag suction drill pipe 201.

[0078] S2.2. Install bearing A601 and anchor plate 7 in bearing groove A102 of alloy drill bit 1, connect grouting pipe 16 to grouting pipe connecting nozzle 1002 at the top, and connect water injection pipe 15 to water spray nozzle 204 of slag suction drill pipe 201.

[0079] S2.3. Integrate slag suction drill pipe 201 and alloy drill bit 1 through connecting thread 8, and install 1 - 2 sections of connecting drill pipe 202 on slag suction drill pipe 201.

[0080] S2.4. Install conversion section 3 on the top section of connecting drill pipe 202.

[0081] S3. Connect conversion chamber joint 4: Connect water injection pipe 15 and grouting pipe 16 to water injection pipe connecting nozzle 1001 and grouting pipe connecting nozzle 1002 of conversion chamber joint 4 respectively to form a pressure channel, and connect conversion chamber joint 4 to the top of conversion section 3 through thread connection.

[0082] S4. Installation of prestressed cable anchor 5: Fabricate a prestressed cable anchor 5 with the designed length, pass the prestressed cable anchor 5 through cable anchor hole 703 on anchor plate 7, and fix it with fixing nut 13.

[0083] S5. Water injection to assist in cutting anchor hole 9.

[0084] S5.1. The drill rig rotates in a cycle and simultaneously injects high-pressure water through grouting pipe 16 to cut the hole.

[0085] S5.2. When all connecting drill pipes 202 are drilled into anchor hole 9, remove conversion section 3 by reverse circulation, extend grouting pipe 16 and water injection pipe 15, and at the same time add 1 - 2 sections of connecting drill pipe 202.

[0086] S5.3. Reconnect the transition section 3 and continue to inject water to cut the anchor cable hole 703.

[0087] S5.4. Drill and construct in a cycle according to the sequence of S5.1 to S5.3 until the designed hole depth is reached.

[0088] S6. Hole formation inspection and cleaning: Detect the depth of the anchor hole 9 through the length of the drill pipe 2, and continuously inject clean water 19 through the grouting pipe 16 to clean the hole.

[0089] S7. Pull out the drill pipe 2 while injecting high-pressure grout and water synchronously.

[0090] S7.1. Apply negative pressure through the slag discharge port 409 to pull the slurry plug 25 out of the slag suction hole 203.

[0091] S7.2. After the hole formation is completed, perform high-pressure rotary jet grouting at the bottom of the hole through the high-pressure nozzle 103 to form an enlarged high-pressure grouting body.

[0092] S7.3. During grouting, inject clean water 19 through the water injection pipe 15 synchronously to clean the prestressed anchor cable 5 and the anchor cable 9 above the slag suction hole 203; continuously apply negative pressure during construction to suck out the mud and slag mixture 18 at the bottom of the hole synchronously.

[0093] S7.4. Slowly pull out the drill, while injecting high-pressure grout, water and cleaning slag synchronously until the end of the anchorage section.

[0094] S7.5. Continue to pull out the drill, while injecting grout, water and cleaning slag synchronously until the hole opening, and the grouting is carried out under normal pressure.

[0095] S8. Tensioning of the prestress of the anchor cable: Install the backing plate and the anchor head on the slope surface, and perform graded tensioning. After the tensioning is completed, seal the anchor head.

[0096] The above embodiments are only used to explain the technical concept of the present invention, rather than limiting the protection scope of the rights of the present invention. Any non-substantive modification made to the present invention using this concept shall fall within the protection scope of the present invention.

Claims

1. Anchor hole drilling equipment for easily caving strata, characterized in that It consists of an alloy drill bit (1), a drill pipe (2), a conversion section (3), a conversion chamber joint (4), a prestressed anchor cable (5), an anchor plate (7), a centering support (24), a water injection pipe (15), and a grouting pipe (16); The top of the alloy drill bit (1) is provided with an external thread (802), and a grouting channel (101) is arranged inside. A grouting pipe connecting nozzle (1002) is provided at the top of the grouting channel (101). A check valve (104) and a high-pressure nozzle (103) are successively arranged at the bottom end of the grouting channel (101). A circumferential bearing groove A (102) is arranged around the alloy drill bit (1), and a bearing A (601) is arranged in the bearing groove A (102). The top of the alloy drill bit (1) is successively connected to the drill pipe (2), the conversion section (3), and the conversion chamber joint (4); The drill pipe (2) includes a slag suction drill pipe (201) connected to the alloy drill bit (1) and connecting drill pipes (202) that are successively thread-connected in the upper part. An internal thread (801) for connection is provided at the bottom of the drill pipe (2), and an external thread (802) for connection is provided at the top. A slag suction hole (203) is arranged on the rod body of the slag suction drill pipe (201). A slurry plug (25) is installed in the slag suction hole (203), and a water spray nozzle (204) is provided 20 - 50 cm above the slag suction hole (203); The conversion section (3) is arranged between the connecting drill pipe (202) and the conversion chamber joint (4), and internal threads (801) are provided at both the upper and lower ends; The described conversion bin joint (4) is composed of an upper closed cover plate (403), a fixed joint (401), a lower rotating joint (402), and a bottom plate (404). Inside the conversion bin joint (4), the bin wall (4010) divides it into a grouting conversion bin, a water injection conversion bin, and a slag suction conversion bin from the inside outwards; on the described closed cover plate (403), there are a water injection port (407), a grouting port (408), and a slag discharge port (409); at the bottom of the fixed joint (401), there is a bearing expansion bin (405) larger than the diameter of the fixed joint (401). Inside the bearing expansion bin (405), there is a bearing B (602) and a snap ring (11). At the bottom of the three bin walls (4010) inside the fixed joint (401), there are smooth ends (4011) with a semi-circular cross-section. On the smooth ends (4011), there are 1 to 3 sealing ring grooves (4013), and sealing rings (23) are arranged in the sealing ring grooves (4013); on the outer bin wall (4010) of the conversion bin joint (4), there is an external thread (802). At the top of the bin wall (4010), there is a U-shaped ring groove (4012) matching the smooth end (4011). The sealing space formed by the sealing ring (23), the smooth end (4011) of the bin wall (4010), and the U-shaped ring groove (4012) is filled with lubricating grease (12); at the center of the bottom plate (404), there is a center plate (4041), and on the outside, there is an outer ring plate (4042). Between the two, there are connecting rods (4043) for connection. On the center plate (4041), there are a water injection pipe connection nozzle (1001) and a grouting pipe connection nozzle (1002). The described prestressed anchor cable (5) is arranged around the drill pipe (2) and is fixed to the bearing A (601) of the alloy drill bit (1) through the anchor plate (7) and the fixing nut (13) at the bottom. On the described anchor plate (7), there is a drill pipe hole (702), and a plurality of anchor cable holes (703) are evenly arranged outside the drill pipe hole (702); above the drill pipe hole (702) of the anchor plate (7), there is also a bearing groove B (701) with the same outer diameter as the bearing (6). The described centering brackets (24) are spaced on the prestressed anchor cables (5) to integrate multiple steel strands into a whole. The described water injection pipe (15) and grouting pipe (16) are arranged inside the drill pipe (2). The two ends of the grouting pipe (16) are respectively connected to the alloy drill bit (1) and the grouting pipe connection nozzle (1002) on the conversion bin joint (4). The two ends of the water injection pipe (15) are respectively connected to the water spray nozzle (204) of the slag suction drill pipe (201) and the water injection pipe connection nozzle (1001) on the conversion bin joint (4).

2. The anchor cable hole forming device for easily caving strata according to claim 1, characterized in that, The inner diameter ring of the bearing A (601) is installed inside the bearing groove A (102) of the alloy drill bit (1), and the outer diameter ring is installed inside the bearing groove B (701) of the anchor plate (7). The bearing groove A (102) has the same inner diameter as the bearing A (601), and the bearing groove B (701) has the same outer diameter as the bearing A (601).

3. The anchor hole forming device for easily caving strata according to claim 1, characterized in that The described slurry plug (25) is provided with a wedge-shaped installation opening, which is arranged inside the slag suction hole (203). Before slag suction, it is evacuated from the slag suction hole (203) through negative pressure.

4. The hole-forming device for anchor cables in easily caving strata according to claim 1, characterized in that, The internal threads (801) and external threads (802) involved in the alloy drill bit (1), drill pipe (2), conversion section (3) and conversion chamber joint (4) match each other and are connected up and down to form a whole.

5. The anchor cable hole forming device for easily caving strata according to claim 1, wherein During the drilling process of the anchor hole (9), the described grouting port (408) injects clear water (19) for cutting to assist in hole formation. During the extraction process of the drill pipe (2), high-pressure jet grouting of cement slurry (17) is carried out to form a grouting and anchoring section; during the extraction process of the drill pipe (2), the described water injection port (407) injects clear water (19) to clean the hole; during the extraction process of the drill pipe (2), the slag outlet (409) sucks out the sludge mixture (18) in the hole under negative pressure.

6. The anchor cable hole-forming device for easily caving strata according to claim 1, characterized in that The described snap ring (11) is arranged in the snap ring groove (406) of the bearing expansion chamber (405) at the bottom of the bearing B (602), restricting the bearing B (602) within the bearing expansion chamber (405); the outer diameter of the bearing B (602) is the same as the inner diameter of the bearing expansion chamber (405), and the inner diameter is the same as the outer diameter of the wall (4010) of the rotating joint (402), so that the rotating joint (402) rotates relative to the fixed joint (401).

7. The anchor cable hole-forming equipment for easily caving strata according to claim 1, characterized in that, The diameters of the described closed cover plate (403) and bottom plate (404) are the same as the outer diameter of the conversion chamber joint (4), and they are respectively fixed to the top and bottom of the fixed joint (401) and the rotating joint (402); the diameter of the central plate (4041) on the bottom plate (404) is the same as the diameter of the water injection conversion chamber, and the connecting rod (4043) is inside the slag suction conversion chamber.

8. The anchor cable hole forming device for easily caving strata according to claim 1, characterized in that, The cement slurry (17) in the described grouting pipe (16) is injected from the grouting port (408) into the conversion chamber joint (4), transported through the grouting pipe (16) and sprayed out from the high-pressure nozzle (103) of the alloy drill bit (1) at high pressure; the clear water (19) in the water injection pipe (15) is injected from the water injection port (407) into the conversion chamber joint (4), transported through the water injection pipe (15) and sprayed out from the water spray nozzle (204) of the slag suction drill pipe (201); the sludge mixture (18) in the anchor hole (9) flows into the slag suction hole (203) of the slag suction drill pipe (201), flows from the inside of the drill pipe (2) towards the conversion chamber joint (4), and is discharged from the slag outlet (409).

9. A synchronous hole flushing and grouting construction method for the hole forming equipment of the anchor cable in the easily caving stratum according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Pilot hole: Drill a pilot hole with a depth of 1.0 m on the slope surface. S2. Installation of drill pipe (2): Assemble the alloy drill bit (1), slag suction drill pipe (201), connecting drill pipe (202), conversion section (3) and conversion chamber joint (4) in sequence. S2.

1. Install a slurry plug (25) with the same cross-section as the slag suction hole (203) in the slag suction hole (203) of the slag suction drill pipe (201). S2.

2. Install the bearing A (601) and the anchoring plate (7) in the bearing groove A (102) of the alloy drill bit (1), connect the grouting pipe (16) to the top grouting pipe connection nozzle (1002), and connect the water injection pipe (15) to the water spray nozzle (204) of the slag suction drill pipe (201). S2.

3. Integrate the slag-suction drill pipe (201) and the alloy drill bit (1) into a whole through the connecting thread (8), and install 1 to 2 sections of connecting drill pipes (202) on the slag-suction drill pipe (201); S2.

4. Install the conversion section (3) on the top connecting drill pipe (202); S3. Connect the conversion chamber joint (4): Connect the water injection pipe (15) and the grouting pipe (16) to the water injection pipe connecting nozzle (1001) and the grouting pipe connecting nozzle (1002) of the conversion chamber joint (4) respectively to form a pressure channel, and connect the conversion chamber joint (4) to the top of the conversion section (3) by thread connection; S4. Installation of prestressed anchor cable (5): Fabricate a prestressed anchor cable (5) of the designed length, pass the prestressed anchor cable (5) through the anchor cable hole (703) on the anchor plate (7), and fix it with the fixing nut (13); S5. Water injection-assisted cutting of the anchor hole (9): S5.

1. The drill rig drills in a cycle and simultaneously injects high-pressure water through the grouting pipe (16) to cut the hole; S5.

2. When all the connecting drill pipes (202) are drilled into the anchor hole (9), the conversion section (3) is removed by reverse circulation, the grouting pipe (16) and the water injection pipe (15) are lengthened, and 1 to 2 sections of connecting drill pipes (202) are added at the same time; S5.

3. Reconnect the conversion section (3) and continue to inject water to cut the anchor cable hole (703); S5.

4. Drill and construct in a cycle according to the sequence of S5.1 to S5.3 until the designed hole depth is reached; S6. Hole formation detection and cleaning: Detect the depth of the anchor hole (9) through the length of the drill pipe (2), and continuously inject clean water (19) through the grouting pipe (16) to clean the hole; S7. Pull out the drill pipe (2) while injecting high-pressure grout and water: S7.

1. Apply negative pressure through the slag outlet (409) to pull the slurry plug (25) out of the slag suction hole (203); S7.

2. After the hole formation is completed, perform high-pressure rotary jet grouting at the bottom of the hole through the high-pressure nozzle (103) to form an enlarged high-pressure grouting body; S7.

3. When grouting, simultaneously inject clean water (19) through the water injection pipe (15) to clean the prestressed anchor cable (5) above the slag suction hole (203) and the anchor hole (9); Continuously apply negative pressure during construction to suck out the mud and slag mixture (18) at the bottom of the hole; S7.

4. Slowly pull out the drill, while injecting high-pressure grout, water and cleaning the slag, until the end of the anchorage section; S7.

5. Continue to pull out the drill, while grouting, injecting water and cleaning the slag until the hole mouth, and the grouting is carried out under normal pressure; S8. Prestress tensioning of the anchor cable: Install the backing plate and the anchor head on the slope surface, and perform graded tensioning. After the tensioning is completed, seal the anchor head.

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