High-pressure jet grouting anchor cable drill body and construction method thereof

Abstract

The invention discloses a high-pressure jet grouting anchor cable drill body and a construction method thereof, and relates to the technical field of geotechnical engineering anchoring support. The drill body sequentially comprises a drill bit penetrating through a hollow drill rod, a ratchet wheel structure, a bearing structure, a fixing disc, a limiting ring, a contraction mechanism, a plurality of wiring rings and a plurality of anchor cables penetrating through the wiring rings from bottom to top. The ratchet wheel structure is composed of a ratchet wheel and a ratchet pawl, the ratchet wheel is fixedly connected to the drill rod, and the ratchet pawl is fixedly connected to the inner wall of the drill bit. The anchor cable penetrates through the stringing ring fixed on the drill rod and the fixed disc and is fixed on the fixed disc through the extrusion sleeve; the interior of the contraction mechanism is a structure which is composed of three iron rings, a deflector rod and a rocker arm and changes rotary motion into linear motion, and the exterior of the contraction mechanism is composed of a contractible rhombic structure. A threaded sleeve of the bearing structure is arranged on the inner wall of the rolling bearing, and the inner wall of the threaded sleeve is located at the drill rod threads. The bearing capacity of the anchor cable and the construction quality of an anchoring body are improved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering anchoring support, and in particular to a high-pressure rotary jet anchor cable drill body and a construction method thereof. Background Art

[0002] The rotary jet anchor cable is developed by combining the rotary jet pile with the ordinary anchor cable. It is a newer anchoring technology that increases the anchoring force by increasing the diameter of the anchor body. During the anchoring process, the rotating high-pressure cement slurry and high-pressure gas complete the cutting and hole-forming of the soil around the anchor hole wall. The cement slurry and the soil are fully mixed and combined to form the anchor cable body. At the same time, the high-pressure cement slurry completes the penetration and reinforcement of the weak soil around the anchor cable, which not only improves the lateral resistance of the anchor cable structure, but also the high-pressure sprayed cement slurry fills the gaps in the soil around the anchor cable and consolidates the soil, further improving the stability of the foundation pit structure.

[0003] Jet-jet anchors are widely used in soft soil layers because of their advantages such as low construction noise, no mud pollution, reliable quality, fast construction progress, standardized production, large anchor diameter and high anchoring force per unit length.

[0004] In practice, when high-pressure rotary jet anchor cable is constructed in soft soil areas such as silt, due to the serious creep of soft soil, there are phenomena such as diameter shrinkage and easy hole collapse during hole formation. The prior art application number "202410715770.8" proposes a high-pressure rotary jet anchor cable drill body, which provides a second spray hole at the bearing to reinforce the soil bag around the hole during the drilling withdrawal process and improve the grouting effect. However, the steel strand in the anchor body is a flexible object, and the steel strand will be out of center and twisted during the cable drilling process and the drilling withdrawal process. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a high-pressure rotary jet anchor drill body and a construction method thereof.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A high-pressure rotary jet anchor cable drill body comprises, from bottom to top, a drill bit passing through a hollow drill rod, a ratchet structure, a bearing structure, a fixing plate, a limit ring, a contraction mechanism, a plurality of stringing rings and a plurality of anchor cables passing through the stringing rings.

[0008] The ratchet structure consists of a ratchet and a ratchet pawl, the ratchet is fixedly connected to the drill rod, and the ratchet pawl is fixedly connected to the inner wall of the drill bit; the anchor cable passes through the stringing ring and the fixed disk fixed on the drill rod, and the anchor cable is fixed to the fixed disk by an extrusion sleeve; the rotation direction of the ratchet is consistent with that of the drill rod when entering the hole; the unidirectional rotation feature of the ratchet can prevent the drill rod from being separated from the drill bit during the drill withdrawal process.

[0009] The threaded sleeve of the bearing structure is arranged on the inner wall of the rolling bearing, and the inner wall of the threaded sleeve is located at the thread of the drill rod.

[0010] The interior of the retracting mechanism is composed of three iron rings, a lever and a rocker arm to convert rotational motion into linear motion, and the exterior is composed of a retractable diamond structure.

[0011] Specific:

[0012] The outside of the contraction mechanism is composed of a circular ring, a contraction belt, a semi-cylindrical block, a spring, a linear slide groove, and a limit seat; the two semi-cylindrical blocks are connected by a circular ring at their close positions, the semi-cylindrical block is movably connected to the circular ring at one end near the drill bit, half of the circular ring at the end near the expansion hole is fixedly connected, and the other half is movably connected to the semi-cylindrical block. The contraction mechanism can support the basalt fiber of the anchor cable in the relaxed state, so that the basalt fiber is straightened and centered.

[0013] A spring is arranged between the upper and lower semi-cylindrical blocks. When the upper cylindrical block encounters resistance, that is, when it hits the wire ring, resistance is generated, the spring stretches, and the movable ring on the lower semi-circular block moves along the linear slide groove, and the contraction belt contracts to realize the tightening state of the contraction mechanism.

[0014] The radius of the upper and lower semi-cylindrical blocks in the straight state is smaller than the radius of the stringing ring, so the contraction mechanism can smoothly pass through the inner circle of the stringing ring; after passing through the inner circle of the stringing ring, the spring rebounds naturally, the contraction mechanism expands, and then continues to provide central support for the basalt fiber anchor cable.

[0015] The contraction mechanism is composed of a left iron ring, a middle iron ring, a right iron ring, a lever and a rocker arm. The left, middle and right iron rings can rotate around the drill pipe. Ball bearings are installed inside the iron rings, which can deflect synchronously and are driven to rotate by the edge of the inner ring of the bearing contacting the drill pipe. The friction force on the three bearings generates axial force components in the same direction. Therefore, the three iron rings are driven by the axial force components to drive the contraction mechanism to move linearly together through the bearings.

[0016] The inner ring of the bearing in the iron ring presses the drill rod tightly. The center of the bearing inside the left iron ring does not coincide with the axis of the drill rod, but is above and to the side of the center of the drill rod cross section. In this way, after the bearing is driven and deflected by the drill rod, only one point of the inner ring on the side and below contacts the drill rod, which makes the contact point of the bearing receive friction in the tangential direction of the inner ring. This friction generates a component force along the axial direction of the drill rod. The same is true for the right iron ring. The friction force received by the contact point of the bearing also generates a component force in the same direction. Since the deflection direction of the middle iron ring is opposite, its bearing center is below and to the side of the center of the drill rod cross section, resulting in only one point of the inner ring of the bearing on the side and above contacts the drill rod. When it is subjected to friction in the tangential direction, the axial component force generated is in the same direction as that of the two outer bearings. The friction forces received by the three bearings all generate axial components in the same direction. Therefore, the three iron rings are subjected to the axial component force and move linearly together through the bearing-driven contraction mechanism.

[0017] When retracting the drill, the reversing lever is touched, and the deflection direction of the three iron rings is changed at the same time. The direction of the friction force on the three bearings will change instantly, causing the axial force component to change direction. The contraction mechanism moves in the opposite direction. The lever is actually moving the middle iron ring to offset. There are protruding columns on the edge of the middle iron ring, which push the two adjacent iron blocks through the V-shaped rocker arm on top, followed by reverse deflection. When the lever is touched during retracting the drill, the direction of movement can be switched immediately.

[0018] If the bearings in the left and right iron rings are moved slightly downward, and the bearing in the middle iron ring is moved slightly upward, then the three bearings need a larger deflection angle to contact the drill pipe. The tangential friction force on the bearing contact point produces a larger axial force component, making the retraction mechanism move faster. Therefore, by moving the installation position of the bearing up and down, the maximum deflection angle of the iron ring can be changed, thereby changing the size of the axial thrust, realizing stepless speed-changing pitch adjustment.

[0019] The lever actually moves the middle iron ring. There are protruding columns on the edge of the middle iron ring, which push the two adjacent iron blocks through the V-shaped rocker arm on top, followed by reverse deflection. When the lever is touched, the direction of movement can be switched immediately.

[0020] The drill bit is provided with a first nozzle; the thread is provided with a second nozzle.

[0021] The construction process of the present invention is as follows:

[0022] Step 1: Construction preparation and hole position determination: Before starting formal construction, prepare materials for inspection and mechanical equipment for on-site entry; use a level and steel ruler to determine the hole position and make markings.

[0023] Step 2: Jet jet drilling and anchor cable entry: Aim the special high-pressure jet jet anchor drill at the already placed hole position, adjust the angle to perform jet jet drilling. During the anchor cable drilling construction, the drill bit pushes the basalt fiber into the hole gradually through the anchor plate as the drill bit drills forward. The front end of the anchor body increases the water injection pressure and the number of reciprocating advances and retreats of the drill bit to further ensure the anchoring quality of the anchor cable, while increasing the anchor hole diameter to form an enlarged head structure, which greatly improves the pull-out resistance of the anchor cable.

[0024] Step 3: Grouting the anchor hole and jetting back the drill: High-pressure cement slurry is sprayed outward from the first nozzle of the bottom drill bit and the second nozzle of the flank under the pressure of the high-pressure pump. When the drill is pulled out, the jetting drill bit is pulled out of the anchor hole, and the drilling is pulled out while re-stirring and re-spraying are carried out, and a two-stirring and two-spraying construction is carried out;

[0025] Step 4, secondary grouting and tensioning and locking: When the drill is withdrawn to the free section, cement slurry is used for grouting. The water-cement ratio of the grouting can be appropriately increased. The slurry should fill the anchor hole. The tensioning sequence of the anchor cable is one every other anchor cable to consider the impact on the adjacent anchor rods. After tensioning and locking, if there is obvious prestress loss, compensatory tensioning should be carried out.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] High-pressure rotary sprayed glass fiber anchor cable replaces traditional steel anchor rod anchor cable with basalt fiber anchor cable, which improves the bearing capacity of anchor cable under the same construction conditions; the ratchet structure can utilize the one-way rotation feature of the ratchet to avoid the drill rod and drill bit from separating during the drill withdrawal process; the telescopic structure can be used to center the basalt fiber anchor cable, thereby improving the construction quality of the anchor body; by increasing the water injection pressure and the reciprocating advance and retreat of the drill bit at the front end of the anchor body, the anchor quality of the anchor cable is further guaranteed, and at the same time the anchor hole diameter is increased to form an enlarged head structure, which greatly improves the pull-out resistance of the anchor cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the present invention;

[0029] Figure 2 It is a schematic diagram of the internal structure of the rotary linear motion of the present invention;

[0030] Figure 3 It is a schematic diagram of the telescopic structure of the supporting anchor cable structure of the present invention;

[0031] Markings in the figure: 1. drill bit; 2. first nozzle; 3. ratchet structure; 4. thread; 5. extrusion sleeve; 6. fixed plate; 7. rolling bearing; 8. second nozzle; 9. limit ring; 10. retraction mechanism; 11. anchor cable; 12. wire ring; 13. drill rod; 14. left iron ring; 15. lever; 16. middle iron ring; 17. rocker arm; 18. right iron ring; 19. circular ring; 20. retraction belt; 21. limit seat; 22. linear slide; 23. spring; 24. semi-cylindrical block. DETAILED DESCRIPTION

[0032] like Figure 1-Figure 3As shown, the present invention provides a high-pressure rotary jet anchor cable drill body, the drill body comprises, from bottom to top, a drill bit 1 passing through a hollow drill rod 13, a ratchet structure 3, a bearing structure, a fixed plate 6, a limit ring 9, a contraction mechanism 10, a plurality of stringing rings 12 and a plurality of anchor cables 11 passing through the stringing rings 12; the ratchet structure 3 is composed of a ratchet and a ratchet claw, the ratchet is fixedly connected to the drill rod 13, and the ratchet claw is fixedly connected to the inner wall of the drill bit 1; the anchor cable 11 passes through the stringing ring 12 and the fixed plate 6 fixed on the drill rod 13, and the anchor cable 11 is fixed to the fixed plate 6 by an extrusion sleeve 5; the contraction mechanism 10 is internally composed of three iron rings plus a lever 15 and a rocker arm 17 to form a structure for converting rotational motion into linear motion, and the outside is composed of a contractible rhombus structure; the threaded sleeve of the bearing structure is placed on the inner wall of the rolling bearing 7, and the inner wall of the threaded sleeve is located at the thread 4 of the drill rod 13.

[0033] The ratchet structure 3 is composed of a ratchet fixed around the connecting rod and a pawl fixed to the inner wall of the drill bit 1. The rotation direction of the ratchet is consistent with that of the drill rod 13 when entering the hole. When drilling, the drill rod 13 drives the drill bit 1 to rotate. Due to the unidirectional rotation characteristic of the ratchet, during the drilling withdrawal process, the drill bit 1 does not rotate with the drill rod 13, thereby preventing the drill rod 13 from detaching from the drill bit 1.

[0034] The outside of the contraction mechanism 10 is composed of a ring 19, a contraction belt 20, a semi-cylindrical block 24, a spring 23, a linear slide 22, and a limit seat 21; the connection relationship between the various components is: the two semi-cylindrical blocks 24 are connected by the ring 19 at the near parts, the semi-cylindrical block 24 is movably connected to the ring 19 at one end near the drill bit 1, half of the ring 19 is fixedly connected near the end of the expansion hole, and the other half is movably connected to the semi-cylindrical block 24. The contraction mechanism 10 can support the basalt fiber of the anchor cable 11 in the relaxed state, so that the basalt fiber is straightened and centered.

[0035] A spring 23 is arranged between the upper and lower semi-cylindrical blocks 24. When the upper cylindrical block encounters resistance, that is, when it hits the wire rack ring 12, resistance is generated, the spring 23 stretches, and the movable ring 19 on the lower semi-circular block moves axially along the linear slide groove 22. The contraction belt 20 contracts to realize the tightening state of the contraction mechanism 10 so that it can pass through the inner ring of the wire rack ring 12 smoothly.

[0036] The radius of the upper and lower semi-cylindrical blocks 24 in the straight state is smaller than the radius of the inner circle of the stringing ring 12, so the contraction mechanism 10 can smoothly pass through the inner circle of the stringing ring 12; after passing through the inner circle of the stringing ring 12, the spring 23 rebounds naturally, and the contraction mechanism 10 expands, thereby continuing to centrally support the basalt fiber anchor cable 11.

[0037] The contraction mechanism 10 is composed of a left iron ring 14, a middle iron ring 16, a right iron ring 18, a lever 15, and a rocker arm 17. The left, middle, and right iron rings 18 can rotate around the drill rod 13. Ball bearings are installed inside the iron rings, which can deflect synchronously and are driven to rotate by the edge of the inner ring of the bearing contacting the drill rod 13. The friction force on the three bearings generates axial force components in the same direction. Therefore, the three iron rings are driven by the axial force components to drive the contraction mechanism 10 to move linearly together through the bearings.

[0038] The inner ring of the bearing in the iron ring is pressed against the drill rod 13. The center of the bearing inside the left iron ring 14 does not coincide with the axis of the drill rod 13, but is above the center of the cross section of the drill rod 13. In this way, after the bearing is driven to deflect by the drill rod 13, only one point of the inner ring below the side contacts the drill rod 13, which makes the contact point of the bearing subject to friction in the tangential direction of the inner ring. This friction generates a component force along the axial direction of the drill rod 13. The right iron ring 18 is the same. The friction force on the contact point of the bearing also generates a component force in the same direction. Since the deflection direction of the middle iron ring 16 is opposite, its bearing center is below the center of the cross section of the drill rod 13, resulting in only one point of the inner ring of the bearing above the side in contact with the drill rod 13. When subjected to friction in the tangential direction, the axial component force generated is in the same direction as that of the two outer bearings. The friction forces on the three bearings all generate axial components in the same direction. Therefore, the three iron rings are subjected to the axial component force and the contraction mechanism 10 is driven to move linearly together through the bearing.

[0039] When the drill is withdrawn, the reversing lever 15 is touched, and the deflection direction of the three iron rings is changed at the same time. The direction of the friction force on the three bearings will change instantly, causing the axial force component to change direction. The contraction mechanism 10 moves in the opposite direction. The lever 15 is actually moving the middle iron ring 16 to offset. The edge of the middle iron ring 16 has a protruding column, which pushes the two adjacent iron blocks through the V-shaped rocker arm 17 mounted on it, followed by reverse deflection. When the lever 15 is touched during the drill withdrawal, the direction of movement can be switched immediately.

[0040] If the bearings in the left and right iron rings 18 are moved slightly downward, and the bearing in the middle iron ring 16 is moved slightly upward, then the three bearings need a larger deflection angle to contact the drill rod 13, and the tangential friction force on the bearing contact point produces a larger axial force component, making the movement speed of the contraction mechanism 10 faster. Therefore, by moving the installation position of the bearing up and down, the maximum deflection angle of the iron ring can be changed, thereby changing the size of the axial thrust, and realizing stepless speed-changing pitch adjustment.

[0041] The lever 15 is actually moving the middle iron ring 16 to deflect. The edge of the middle iron ring 16 has a protruding column, which pushes the two adjacent iron blocks through the V-shaped rocker arm 17 on it, followed by reverse deflection. When the lever 15 is touched, the direction of movement can be switched immediately.

[0042] The construction process of the present invention is as follows:

[0043] Step 1: Construction preparation and hole position determination: Before starting formal construction, prepare materials for inspection and mechanical equipment for on-site entry; use a level and steel ruler to determine the hole position and make markings.

[0044] Step 2, jet grouting to form a hole and inserting the anchor cable 11 into the hole: align the special high-pressure jet grouting anchor drilling machine with the already placed hole position, adjust the angle to perform jet grouting to form a hole, and during the anchor cable drilling construction, the drill bit 1 pushes the basalt fiber into the hole gradually through the anchor plate as the drill bit 1 drills forward; since the outer wall thread 4 of the drill rod 13 cooperates with the threaded sleeve, and the threaded sleeve is built in the rolling bearing 7, the fixed plate 6 does not rotate with the drill rod 13, that is, the basalt anchor cable 11 does not rotate with the drill rod 13; the front end of the anchor body increases the water injection pressure and the number of reciprocating advances and retreats of the drill bit 1, so as to further ensure the anchoring quality of the anchor cable 11, and at the same time increase the anchor hole diameter to form an enlarged head structure, so that the pull-out resistance of the anchor cable 11 is greatly improved.

[0045] Step three, anchor hole grouting and rotary jet drilling withdrawal: the high-pressure cement slurry of the high-pressure rotary drill bit 1 is sprayed outward from the first nozzle 2 of the bottom drill bit 1 and the second nozzle 8 of the side wing under the pressure of the high-pressure pump. When pulling out the drill, the rotary jet drill bit 1 withdraws from the anchor plate hole, and starts to stir and spray while pulling out the drill, and performs two-stirring and two-spraying construction; when withdrawing the drill, the contraction mechanism 10 is always in a stretched state when it has not passed through the inner circle of the stringing ring 12, so as to realize the central support of the basalt fiber anchor cable 11, and it is automatically contracted when passing through the stringing ring 12, and it is automatically stretched when passing through to continue to realize the central support of the basalt fiber.

[0046] Step 4, secondary grouting and tensioning and locking: When the drill is withdrawn to the free section, cement slurry is used for grouting. The water-cement ratio of the grouting can be appropriately increased. The slurry should fill the anchor hole. The tensioning sequence of anchor cable 11 is one-by-one because of the impact on the adjacent anchor rods. After tensioning and locking, if there is obvious prestress loss, compensatory tensioning should be carried out.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-pressure jet grouting anchor cable drill body, characterized in that: From bottom to top, it comprises, in sequence, a drill bit (1) passing through a hollow drill rod (13), a ratchet structure (3), a bearing structure, a fixed plate (6), a limit ring (9), a contraction mechanism (10), a plurality of stringing rings (12), and a plurality of anchor cables (11) passing through the stringing rings (12); a first nozzle (2) is provided on the drill bit (1); The ratchet structure (3) comprises a ratchet and a ratchet pawl, the ratchet is fixedly connected to the drill rod (13), and the ratchet pawl is fixedly connected to the inner wall of the drill bit (1); the rotation direction of the ratchet is consistent with that of the drill rod (13); The bearing structure comprises a threaded sleeve and a rolling bearing (7), wherein the threaded sleeve is disposed in the inner wall of the rolling bearing (7), and the inner wall of the threaded sleeve is located at the thread (4) of the drill rod (13); a second nozzle (8) is provided at the thread (4); The anchor cable (11) passes through a wire ring (12) and a fixing plate (6) fixed on a drill rod (13), and the anchor cable (11) is fixed to the fixing plate (6) by means of a compression sleeve (5); Inside the contraction mechanism (10), a structure for converting rotational motion into linear motion is provided; The exterior of the retracting mechanism (10) comprises a retractable diamond-shaped structure.

2. A high-pressure jet grouting anchor cable drill body according to claim 1, characterized in that: The structure for converting rotational motion into linear motion comprises a left iron ring (14), a middle iron ring (16), a right iron ring (18), the three iron rings, a lever (15) and a rocker arm (17); the left iron ring (14), the middle iron ring (16) and the right iron ring (18) can all rotate around a drill rod (13); ball bearings are installed inside the iron rings, which can deflect synchronously and are driven to rotate by the edges of the inner rings of the bearings contacting the drill rod (13); the friction forces exerted on the three bearings all generate axial force components in the same direction, so the three iron rings are subjected to the axial force components and drive the contraction mechanism (10) to move linearly together through the bearings; The lever (15) is used to shift the middle iron ring (16), and a protruding column is arranged on the edge of the middle iron ring (16). The V-shaped rocker arm (17) which is sleeved on the top of the middle iron ring (16) pushes the two iron blocks of the next door to deflect in the opposite direction.

3. A high-pressure jet grouting anchor cable drill body according to claim 1, characterized in that: The retractable diamond structure comprises a circular ring (19), a retractable belt (20), a semi-cylindrical block (24), a spring (23), a linear slide groove (22), and a limit seat (21); the two semi-cylindrical blocks (24) are distributed up and down, a spring (23) is arranged between the upper and lower semi-cylindrical blocks (24), the two semi-cylindrical blocks (24) are connected by a circular ring (19) at the adjacent parts, and the semi-cylindrical block (24) is movably connected to the circular ring (19) at one end close to the drill bit (1). Half of the circular ring (19) near one end of the expanded hole is fixedly connected, and the other half is movably connected to the semi-cylindrical block (24). When the upper cylindrical block (24) encounters resistance, the spring (23) is extended, and the movable circular ring (19) on the lower semi-cylindrical block (24) moves along the linear slide groove (22), and the contraction belt (20) contracts to realize the tightening state of the contraction mechanism (10); the contraction mechanism (10) is in a tensioned state to support the steel strand of the anchor cable (11), so that the steel strand is straightened and centered; The radius of the upper and lower semi-cylindrical blocks (24) in the straightened state is smaller than the radius of the wire-hanging ring (12), so the retracting mechanism (10) can smoothly pass through the wire-hanging ring (12).

4. A construction method for a high-pressure jet grouting anchor cable drill body, characterized in that: A high-pressure jet-jet anchor drill body as claimed in any one of claims 1 to 3; The following steps are involved: Step 1: Construction preparation and hole location determination: Before formal construction, prepare materials for inspection and mechanical equipment for site entry; use a level and steel ruler to determine the hole location and make markings; Step 2, jetting holes and anchor cable entry: Aim the special high-pressure jetting anchor drilling machine at the hole position that has been placed, adjust the angle to perform jetting holes, and during the anchor cable drilling construction, the drill bit (1) pushes the steel strands into the hole gradually through the anchor plate as the drill bit (1) drills forward; the front end of the anchor body increases the water injection pressure and the number of reciprocating advances and retreats of the drill bit (1) to further ensure the anchoring quality of the anchor cable, and at the same time increases the diameter of the anchor hole to form an enlarged head structure, thereby improving the pull-out resistance of the anchor cable; Step 3: grouting the anchor hole and jetting back the drill: high-pressure cement slurry is jetted outward from the first nozzle (2) of the bottom drill bit (1) and the second nozzle (8) on the flank under the pressure of the high-pressure pump. When the drill is pulled out, the jetting drill bit (1) is pulled out of the hole of the anchor plate, and the drilling is pulled out while re-stirring and re-spraying are performed, thus performing a two-stirring and two-spraying construction. Step 4, secondary grouting and tensioning and locking: When the drill is withdrawn to the free section, cement slurry is used for grouting. The water-cement ratio of the grouting is increased, and the slurry should fill the anchor hole. The tensioning sequence of the anchor cable (11) is one every other anchor cable to consider the impact on the adjacent anchor rods. After tensioning and locking, if there is obvious prestress loss, compensatory tensioning should be carried out.

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