Variable-diameter stirring drill bit for cement-soil inclined pile construction

Abstract

The invention relates to the technical field of foundation pit construction equipment, in particular to a variable-diameter stirring drill bit for cement-soil inclined pile construction, which comprises a grouting core tube and a sliding drill rod, a lower expansion arm is arranged at the bottom end of the sliding drill rod, an upper expansion arm is arranged on the grouting core tube, and the upper expansion arm and the lower expansion arm are rotatably connected. The sliding drill rod is further provided with a slurry spraying hole, the inner wall, connected with the sliding drill rod, of the grouting core pipe is provided with a limiting structure, and the sliding drill rod is further provided with a centrifugal locking device which can be locked with the limiting structure when the sliding drill rod rotates. The centrifugal locking device can be automatically locked with the limiting structure on the inner wall of the grouting core pipe through centrifugal force, the locking mechanism can ensure that after the upper expansion arm and the lower expansion arm reach the preset reaming diameter, the reaming diameter can be kept constant no matter how the rotating speed changes, and therefore the reaming precision and stability are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit construction equipment, in particular to a variable diameter stirring drill bit for cement soil inclined pile construction. Background Art

[0002] With the continuous increase of underground space construction, the number of foundation pit projects in large underground spaces has increased significantly, resulting in a substantial increase in the cost of horizontal support for foundation pits. However, soil anchor rods are prohibited from use because they exceed the land red line. Therefore, the research and development of foundation pit support piles combined with diagonal bracing piles has become an urgent task. However, the soft soil layer in many coastal areas is relatively thick. If the pile end of the diagonal bracing pile needs to enter the hard soil bearing layer, the diagonal bracing pile will be long, resulting in high cost. Therefore, the use of friction piles with expanded pile ends is an effective means to improve the bearing capacity of diagonal bracing piles such as steel lattice core piles and composite mixing piles, and is being adopted by more and more foundation pit retaining projects.

[0003] However, the existing technology for constructing the friction pile, i.e. the synchronous concentric diagonal bracing pile, has the following defects:

[0004] The traditional hydraulic expansion drill bit device is complex and bulky in structure. When it is used in oblique synchronous concentric diagonal braced piles, the construction is difficult and is limited by the angle and pile diameter. At the same time, since the hydraulic expansion drill bit device uses a hydraulic expansion cylinder piston to drive the wing plate to expand and retract to achieve expansion and retraction, the drill bit needs to be equipped with two oil pipes in the drill pipe in addition to the necessary grouting pipe. This structure has extremely high requirements on the precision and technology of the drill pipe joint manufacturing process. The cylinder piston is set in the drill bit, which increases the processing difficulty. At the same time, during use, the hydraulic seal is prone to failure, resulting in an increase in the failure rate of the drill bit and affecting the construction progress.

[0005] The non-hydraulic type of the prior art, such as the mechanical expansion drill, generally relies only on the resistance of the drill rod when drilling down and the effect of gravity to open the expansion wing plates that are hinged to each other, and automatically closes when lifting upward; there are also some that use the elastic force of the spring to open or retract the expansion stirring wing plates. This expansion stirring structure has low construction accuracy and cannot guarantee the stable expansion size and the reliability, firmness and accuracy of expansion and folding. There are also mechanical expansion drills that require manual insertion and withdrawal of pins to adjust the opening degree of the expansion wing plates that are hinged to each other. The adjustment is relatively difficult, the labor intensity of the workers is relatively high, the construction efficiency is relatively low, and there are certain safety hazards. There are also some hinged wing plates that require a lot of driving force to open again due to the adhesion of silt, etc., which has a certain impact on the construction progress and also increases the energy consumption of the construction process, such as increasing the power consumption of the downward pressure drill bit.

[0006] Chinese patent publication number CN220849576U discloses a mechanical multi-diameter hole-expanding and stirring drill device for foundation pit support and diagonal bracing pile construction, comprising a grouting core tube whose upper end is connected to a cement slurry source and a pump and whose lower end is connected to a grouting port of a drill tip; an active drill tube comprises a tapered sleeve with a small upper portion and a large lower portion in the middle section, an active disk fixed at the bottom end of the tapered sleeve with a small upper portion and a large lower portion, and a circular tube fixed at the bottom surface of the active disk, and an F-shaped slide groove is arranged on the tapered sleeve with a small upper portion and a large lower portion, the active disk and the circular tube; a limiting column is fixed at the top end of the circular drill rod for being embedded in the bottom end of the vertical groove of the F-shaped slide groove to gather the prismatic stirring frame and extract the hole-expanding and stirring drill device from the steel lattice column in a small diameter, or being embedded in the lower transverse groove of the F-shaped slide groove to expand the hole with a medium diameter, or being embedded in the upper transverse groove of the F-shaped slide groove to expand the hole with a large diameter, and the limiting column can slide in the F-shaped slide groove.

[0007] The device presses down the sliding drill rod relative to the grouting core tube. However, when the limit column on the sliding drill rod slides in the F-shaped slide groove, it is difficult to get stuck in the upper horizontal groove, which may cause the adjustment of the hole expansion diameter to be inaccurate and may even cause the sliding to be not smooth.

[0008] Secondly, the device cannot achieve stepless adjustment when adjusting the hole diameter, which means that the adjustment of the hole diameter is discrete rather than continuous, which may limit its use in some application scenarios that require precise control of the hole diameter.

[0009] In addition, when expanding the hole, the device only relies on the rotation of the lower wing plate and the upper wing plate. Although this hole expansion method is simple, it is inefficient because the rotation of the lower wing plate and the upper wing plate consumes a lot of energy, and due to the limitations of the rotation angle and speed, the hole expansion speed may not reach the expected speed. Summary of the invention

[0010] In view of the above problems, a variable diameter mixing drill bit for cement-soil inclined pile construction is provided, which adjusts the hole expansion diameter of the upper expansion arm and the lower expansion arm when the sliding drill rod slides a certain distance relative to the grouting core tube, and a centrifugal locker is arranged on the sliding drill rod, so that when the grouting core tube and the sliding drill rod are rotated, the centrifugal locker can be locked with the limiting structure on the inner wall of the grouting core tube, thereby locking the hole expansion diameter of the upper expansion arm and the lower expansion arm, thereby solving the problem that the existing hole expansion drill bit needs to accurately lock the hole expansion diameter according to the displacement.

[0011] In order to solve the problems of the prior art, the present invention provides a variable diameter mixing drill bit for cement-soil inclined pile construction, comprising a grouting core tube connected to a cement slurry source and a pump, and a sliding drill rod slidably arranged in the grouting core tube, the bottom end of the sliding drill rod is provided with a lower expansion arm rotatably connected thereto, the grouting core tube is provided with an upper expansion arm rotatably connected thereto, the upper expansion arm and the lower expansion arm are rotatably connected, the sliding drill rod is also provided with a grouting hole connected to the grouting core tube, the inner wall of the grouting core tube connected to the sliding drill rod is provided with a limiting structure arranged along its length direction, and the sliding drill rod is also provided with a centrifugal locker which can be locked with the limiting structure when it rotates.

[0012] Preferably, a mounting groove coaxial with the sliding drill rod is provided on the outer circumferential surface of the sliding drill rod, and the centrifugal locker has a centrifugal block that can slide radially along the sliding drill rod in the mounting groove, and a reset assembly that can guide the centrifugal block to reset. When the sliding drill rod rotates, the centrifugal block is driven to move radially and lock with the limiting structure.

[0013] Preferably, the limiting structure is a groove, the centrifugal block has a protrusion that can be inserted into the groove radially, the top of the centrifugal block has a conical surface, the reset assembly has a reset drive ring that elastically abuts on the conical surface, and when the sliding drill rod is in a non-rotating state, the centrifugal block abuts on the side of the mounting groove facing the axis of the sliding drill rod, and the centrifugal block abuts on the bottom of the mounting groove.

[0014] Preferably, a positioning pin is provided at the bottom of the installation groove, the positioning pin extends radially along the sliding drill rod, and a positioning groove slidably matched with the positioning pin is provided on the inner side of the centrifugal block.

[0015] Preferably, the reset assembly further comprises an elastic reset element arranged between the reset drive ring and the top of the mounting groove.

[0016] Preferably, an inner tube is provided in the grouting core tube, a cylindrical sliding cavity is formed between the inner circumference of the grouting core tube and the inner tube, a sliding drill rod is coaxially slidably arranged in the sliding cavity, and an elastic compression element is provided between the top of the sliding cavity and the sliding drill rod.

[0017] Preferably, a universal connector is provided at the bottom end of the sliding drill rod, and a torque output assembly transmission-connected to the universal connector is provided inside the sliding drill rod. When the slurry passes through the sliding drill rod, the torque output assembly inputs torque to the universal connection transmission assembly, and the bottom end of the lower expansion arm is rotationally connected to the universal connector, and the top end of the lower expansion arm is rotationally connected to the bottom end of the upper expansion arm.

[0018] Preferably, the lower expansion arm is a rotating roller, and drill teeth are evenly distributed on the circumferential surface of the rotating roller.

[0019] Preferably, a mounting cavity is provided at the bottom end of the sliding drill rod, and the torque output assembly includes a drive shaft rotatably arranged in the sliding drill rod, arc-shaped blades are arranged on the circumferential surface of the drive shaft along its circumference, and the bottom end of the drive shaft extends into the mounting cavity and is transmission-connected to the universal joint.

[0020] Preferably, a driving bevel gear is disposed at the bottom end of the driving shaft, and a driven bevel gear meshing with the driving bevel gear is disposed at the inner end of the universal joint.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present application can accurately adjust the hole expansion diameter of the upper expansion arm and the lower expansion arm through the relative sliding between the sliding drill rod and the grouting core tube. Specifically, when the sliding drill rod slides a certain distance in the grouting core tube, it will drive the upper expansion arm and the lower expansion arm to move accordingly, thereby changing the size of the hole expansion diameter.

[0023] In order to solve the problem of unstable hole diameter during hole expansion, a centrifugal locker is set on the sliding drill rod. When the grouting core tube and the sliding drill rod start to rotate, the centrifugal locker will use centrifugal force to automatically lock with the limiting structure on the inner wall of the grouting core tube. This locking mechanism can ensure that after the upper expansion arm and the lower expansion arm reach the predetermined hole expansion diameter, the hole expansion diameter can remain constant regardless of how the rotation speed changes, thereby greatly improving the accuracy and stability of hole expansion.

[0024] In the present application, the lower swing arm is driven to rotate by a universal joint and a torque output assembly, so that the lower swing arm not only revolves but also rotates, further improving the hole expansion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a stereoscopic diagram of a variable diameter mixing drill bit for cement soil inclined pile construction.

[0026] Figure 2 The present invention is a three-dimensional cross-sectional view of a variable diameter mixing drill bit for cement soil inclined pile construction.

[0027] Figure 3 The present invention is a cross-sectional view of a variable diameter mixing drill bit for cement soil inclined pile construction.

[0028] Figure 4 yes Figure 3 A partial enlarged view of point A.

[0029] Figure 5 yes Figure 3 A partial enlarged view of point B.

[0030] Figure 6 It is a partial three-dimensional exploded view of a variable diameter mixing drill bit for cement soil inclined pile construction.

[0031] Figure 7 The present invention is a partial stereoscopic diagram of a torque output component in a variable diameter mixing drill bit used in cement soil inclined pile construction.

[0032] Figure 8 The present invention is a stereoscopic diagram of a centrifugal locker in a variable diameter mixing drill bit for cement soil inclined pile construction.

[0033] Fig. 9 It is a three-dimensional exploded view of a centrifugal locker in a variable diameter mixing drill bit for cement soil inclined pile construction.

[0034] The numbers in the figure are: 1, grouting core tube; 11, limiting structure; 12, inner tube; 13, elastic compression element; 14, sliding cavity; 2, sliding drill rod; 21, spraying port; 22, mounting groove; 23, positioning pin; 24, universal connector; 251, drive shaft; 252, arc blade; 253, active bevel gear; 254, driven bevel gear; 26, mounting cavity; 31, upper expansion arm; 32, lower expansion arm; 321, drill tooth; 4, centrifugal lock; 41, centrifugal block; 411, protrusion; 412, conical surface; 421, reset drive ring; 422, elastic reset element. DETAILED DESCRIPTION

[0035] In order to further understand the features, technical means, specific objectives and functions of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] like Figure 1 , Figure 2 and Figure 3 As shown, this application provides:

[0037] A variable diameter mixing drill bit for cement-soil inclined pile construction comprises a grouting core tube 1 connected to a cement slurry source and a pump, and a sliding drill rod 2 slidably arranged in the grouting core tube 1, a lower expansion arm 32 rotatably connected thereto is arranged at the bottom end of the sliding drill rod 2, an upper expansion arm 31 rotatably connected thereto is arranged on the grouting core tube 1, the upper expansion arm 31 and the lower expansion arm 32 are rotatably connected, a grouting hole connected to the grouting core tube 1 is also arranged on the sliding drill rod 2, a limiting structure 11 arranged along its length direction is arranged on the inner wall where the grouting core tube 1 is connected to the sliding drill rod 2, and a centrifugal locker 4 which can be mutually locked with the limiting structure 11 when the sliding drill rod 2 rotates is also arranged on the sliding drill rod 2.

[0038] Before drilling, the grouting core tube 1 directly drives the sliding drill rod 2 to rotate, so that the upper expansion arm 31 and the lower expansion arm 32 are in a retracted state, so that small-diameter drilling can be performed. When large-diameter drilling is required, the torque input to the grouting steel pipe is stopped, so that the centrifugal locker 4 and the limiting structure 11 are unlocked, the sliding drill rod 2 abuts against the bottom of the borehole, and the grouting core tube 1 is pushed into the hole, so that the lower expansion arm 32 and the upper expansion arm 31 are unfolded, and the torque is continued to be input to the grouting core tube 1 without applying pressure, so that the centrifugal locker 4 and the limiting structure 11 are locked, and the grouting core tube 1 is continued to be pressed down, so that the upper expansion arm 31 and the lower expansion arm 32 can expand the hole at a fixed angle, thereby completing the hole expansion operation.

[0039] When recovering the drill bit, stop inputting torque to the grouting core tube 1, unlock the centrifugal locker 4 and the limit structure 11, directly withdraw the grouting core tube 1, and under the action of gravity, slide the drill rod 2 downward, and the upper expansion arm 31 and the lower expansion arm 32 return to their original state, thereby completing the recovery of the drill bit.

[0040] This embodiment can accurately adjust the hole expansion diameter of the upper expansion arm 31 and the lower expansion arm 32 through the relative sliding between the sliding drill rod 2 and the grouting core tube 1. Specifically, when the sliding drill rod 2 slides a certain distance in the grouting core tube 1, it will drive the upper expansion arm 31 and the lower expansion arm 32 to move accordingly, thereby changing the size of the hole expansion diameter.

[0041] In order to solve the problem of unstable hole expansion diameter during hole expansion, a centrifugal locker 4 is provided on the sliding drill rod 2. When the grouting core tube 1 and the sliding drill rod 2 start to rotate, the centrifugal locker 4 will automatically lock with the limiting structure 11 on the inner wall of the grouting core tube 1 by using centrifugal force. This locking mechanism can ensure that after the upper expansion arm 31 and the lower expansion arm 32 reach the predetermined hole expansion diameter, the hole expansion diameter can remain constant regardless of how the rotation speed changes, thereby greatly improving the accuracy and stability of hole expansion.

[0042] like Figure 4 As shown, a mounting groove 22 coaxial with the sliding drill rod 2 is provided on the outer circumferential surface thereof, and the centrifugal locker 4 has a centrifugal block 41 capable of sliding radially along the sliding drill rod 2 in the mounting groove 22, and a reset assembly capable of guiding the centrifugal block 41 to reset. When the sliding drill rod 2 rotates, the centrifugal block 41 is driven to move radially and lock with the limiting structure 11.

[0043] A guide groove extending along its axial direction is also provided on the outer circumferential surface of the sliding drill rod 2, and a guide bar extending along its axial direction is provided on the inner wall of the grouting core tube 1. The guide bar and the guide groove are slidably matched, so that the grouting core tube 1 can drive the sliding drill rod 2 to rotate, thereby avoiding deformation between the upper expansion arm 31 and the lower expansion arm 32.

[0044] When the grouting core tube 1 is in a stationary state, under the action of the reset component, the reset component can guide the centrifugal block 41 away from the limiting structure 11, so that the centrifugal block 41 and the limiting structure 11 are in an unlocked state. When the grouting core tube 1 rotates, the centrifugal block 41 breaks through the action of the reset component and locks with the limiting structure 11 under the action of the rotating centrifugal force, and then can lock the grouting core tube 1 and the sliding drill rod 2, thereby locking the angles of the upper expansion arm 31 and the lower expansion arm 32, thereby achieving on-demand diameter expansion.

[0045] like Figure 4 , Figure 8 and Fig. 9 As shown, the limiting structure 11 is a groove, the centrifugal block 41 has a protrusion 411 that can be inserted into the groove radially, the top of the centrifugal block 41 has a conical surface 412, and the reset assembly has a reset drive ring 421 elastically abutting on the conical surface 412. When the sliding drill rod 2 is in a non-rotating state, the centrifugal block 41 abuts against the side of the mounting groove 22 facing the axis of the sliding drill rod 2, and the centrifugal block 41 abuts against the bottom of the mounting groove 22.

[0046] The inner wall of the grouting core tube 1 is provided with grooves arranged along its length direction, and the centrifugal block 41 is provided with a protrusion 411 that can be engaged with the groove. When the grouting core tube 1 rotates at high speed, the centrifugal block 41 overcomes the elastic force of the reset drive ring 421 and moves away from the axis of the sliding drill bit, so that the protrusion 411 of the centrifugal block 41 can be inserted into the groove, thereby locking the grouting core tube 1 and the sliding drill bit to prevent the upper expansion arm 31 and the lower expansion arm 32 from swinging during hole expansion.

[0047] like Figure 4 As shown, a positioning pin 23 is provided at the bottom of the installation groove 22 , and the positioning pin 23 extends along the radial direction of the sliding drill rod 2 . A positioning groove that slidably cooperates with the positioning pin 23 is provided on the inner side of the centrifugal clamping block 41 .

[0048] The inner side of the centrifugal block 41 is provided with a positioning groove that is slidably matched with the positioning pin 23. The centrifugal block 41 is connected with the positioning pin 23 of the mounting groove 22 to form a tight mechanical matching system. When the centrifugal block 41 moves outward under the action of centrifugal force, the positioning groove inside it will slide along the radial direction of the sliding drill rod 2, thereby ensuring that the centrifugal block 41 can maintain a stable relative position relationship with the positioning pin 23 at any time.

[0049] Such a design not only ensures the stability and reliability of the mechanical parts during high-speed operation, but also greatly improves the working efficiency and service life of the machine. Through the precise matching of the positioning pin 23 and the positioning groove, the mechanical parts can accurately complete the predetermined action, avoiding failures and damages caused by position offset or misalignment.

[0050] like Figure 4 As shown, the reset assembly further includes an elastic reset element 422 disposed between the reset drive ring 421 and the top of the mounting groove 22 .

[0051] By arranging an elastic reset element 422 between the reset drive ring 421 and the top of the mounting groove 22, when the grouting core tube 1 stops rotating, the elastic reset element 422 can push the reset drive ring 421 downward, so that the reset drive ring 421 abuts against the conical surface of the centrifugal block 41 to reset the centrifugal block 41, thereby facilitating the unlocking of the sliding drill rod 2 and the grouting core tube 1.

[0052] like Figure 3 and Figure 4 As shown, an inner tube 12 is provided in the grouting core tube 1, a cylindrical sliding cavity 14 is formed between the inner circumferential surface of the grouting core tube 1 and the inner tube 12, a sliding drill rod 2 is coaxially slidingly arranged in the sliding cavity 14, and an elastic compression element 13 is provided between the top end of the sliding cavity 14 and the sliding drill rod 2.

[0053] An inner tube 12 is arranged in the grouting core tube 1, so that a cylindrical sliding cavity 14 is formed between the inner circumferential surface of the grouting core tube 1 and the inner tube 12, and the sliding drill rod 2 is coaxially slidingly arranged in the sliding cavity 14, which can prevent mud from entering the sliding cavity 14 and corroding the centrifugal locker 4. In order to make the upper expansion arm 31 and the lower expansion arm 32 be in a retracted state in the initial state, the elastic compression unit can apply a force to the sliding drill bit, so as to reset the upper expansion ratio and the lower expansion arm 32.

[0054] like Figure 5 As shown, a universal connector 24 is provided at the bottom end of the sliding drill rod 2, and a torque output assembly connected to the universal connector 24 is provided inside the sliding drill rod 2. When the slurry passes through the sliding drill rod 2, the torque output assembly inputs torque to the universal connection transmission member, and the bottom end of the lower expansion arm 32 is rotationally connected to the universal connector 24, and the top end of the lower expansion arm 32 is rotationally connected to the bottom end of the upper expansion arm 31.

[0055] In order to improve the hole expansion efficiency, a torque output assembly is arranged in the sliding drill rod 2, and the mud enters the sliding drill bit through the grouting core tube 1 and is sprayed out through the grouting port 21. During this process, the mud guides the torque output assembly to input torque to the universal connector 24, so that the lower expansion arm 32 connected to the universal connector can rotate at high speed, so that the lower expansion arm 32 rotates by itself while rotating in the circumferential direction, thereby improving the hole expansion efficiency.

[0056] The universal joint 24 can ensure that the lower expansion arm 32 can rotate at different angles.

[0057] like Figure 6 As shown, the lower expansion arm 32 is a rotating roller, and drill teeth 321 are evenly distributed on the circumferential surface of the rotating roller.

[0058] By providing the drill teeth 321 on the rotating roller, the hole enlarging efficiency after the lower expansion arm 32 rotates is further improved.

[0059] like Figure 7 As shown, a mounting cavity 26 is provided at the bottom end of the sliding drill rod 2, and the torque output assembly includes a drive shaft 251 rotatably disposed in the sliding drill rod 2, and arc-shaped blades 252 are arranged along the circumferential direction on the circumferential surface of the drive shaft 251, and the bottom end of the drive shaft 251 extends into the mounting cavity 26 and is transmission-connected to the universal joint 24.

[0060] When the slurry acts on the blades of the arc blade 252 axially, the arc blade 252 is subjected to the force to drive the drive shaft 251 to rotate in the sliding drill rod 2, so that the drive shaft 251 can drive the universal joint 24 to rotate, so that the lower expansion arm 32 can rotate relative to the sliding drill rod 2, so that when the sliding drill rod 2 rotates, the rotating lower expansion arm 32 can revolve and rotate, so as to improve the hole expansion efficiency.

[0061] like Figure 5 and Figure 6 As shown, a driving bevel gear 253 is disposed at the bottom end of the driving shaft 251 , and a driven bevel gear 254 meshing with the driving bevel gear 253 is disposed at the inner end of the universal joint 24 .

[0062] The driving shaft 251 can drive the active bevel gear 253 to rotate, and the active bevel gear 253 is meshed with the driven bevel gear 254, so that the active bevel gear 253 can input torque to the driven bevel gear 254, thereby enabling the universal joint 24 to rotate at the bottom end of the sliding drill rod 2, thereby driving the lower expansion arm 32 to rotate.

[0063] The above embodiments only express one or several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A variable diameter mixing drill bit for cement soil inclined pile construction, comprising a grouting core tube (1) connected to a cement slurry source and a pump, and a sliding drill rod (2) slidably arranged in the grouting core tube (1), the bottom end of the sliding drill rod (2) is provided with a lower expansion arm (32) rotatably connected thereto, the grouting core tube (1) is provided with an upper expansion arm (31) rotatably connected thereto, the upper expansion arm (31) and the lower expansion arm (32) are rotatably connected, the sliding drill rod (2) is also provided with a grouting hole connected to the grouting core tube (1), characterized in that: The inner wall of the grouting core tube (1) connected to the sliding drill rod (2) is provided with a limiting structure (11) arranged along its length direction, and the sliding drill rod (2) is also provided with a centrifugal locker (4) which can be locked with the limiting structure (11) when rotating.

2. A variable diameter mixing drill bit for cement soil inclined pile construction according to claim 1, characterized in that: The outer circumferential surface of the sliding drill rod (2) is provided with a coaxial mounting groove (22), and the centrifugal locker (4) comprises a centrifugal clamping block (41) which can slide radially along the sliding drill rod (2) in the mounting groove (22), and a reset assembly which can guide the centrifugal clamping block (41) to reset. When the sliding drill rod (2) rotates, the centrifugal clamping block (41) is driven to move radially and lock with the limiting structure (11).

3. A variable diameter mixing drill bit for cement soil inclined pile construction according to claim 2, characterized in that: The limiting structure (11) is a groove, the centrifugal clamp (41) has a protrusion (411) that can be inserted into the groove in a radial direction, the top of the centrifugal clamp (41) has a conical surface (412), the reset assembly has a reset drive ring (421) elastically abutting against the conical surface (412), and when the sliding drill rod (2) is in a non-rotating state, the centrifugal clamp (41) abuts against a side of the mounting groove (22) facing the axis of the sliding drill rod (2), and the centrifugal clamp (41) abuts against the bottom of the mounting groove (22).

4. The variable diameter mixing drill bit for cement soil inclined pile construction according to claim 3, characterized in that: A positioning pin (23) is provided at the bottom of the installation groove (22), the positioning pin (23) extends radially along the sliding drill rod (2), and a positioning groove slidably matched with the positioning pin (23) is provided on the inner side of the centrifugal clamping block (41).

5. The variable diameter mixing drill bit for cement soil inclined pile construction according to claim 3, characterized in that: The reset assembly also includes an elastic reset element (422) arranged between the reset drive ring (421) and the top of the installation groove (22).

6. A variable diameter mixing drill bit for cement soil inclined pile construction according to any one of claims 1 to 5, characterized in that: An inner tube (12) is arranged in the grouting core tube (1), a cylindrical sliding cavity (14) is formed between the inner circumferential surface of the grouting core tube (1) and the inner tube (12), a sliding drill rod (2) is coaxially slidably arranged in the sliding cavity (14), and an elastic compression element (13) is arranged between the top end of the sliding cavity (14) and the sliding drill rod (2).

7. A variable diameter mixing drill bit for cement soil inclined pile construction according to any one of claims 1 to 5, characterized in that: A universal connecting piece (24) is arranged at the bottom end of the sliding drill rod (2), and a torque output assembly which is transmission-connected to the universal connecting piece (24) is arranged inside the sliding drill rod (2). When slurry passes through the sliding drill rod (2), the torque output assembly inputs torque to the universal connecting transmission piece, and the bottom end of the lower expansion arm (32) is rotationally connected to the universal connecting piece (24), and the top end of the lower expansion arm (32) is rotationally connected to the bottom end of the upper expansion arm (31).

8. The variable diameter mixing drill bit for cement soil inclined pile construction according to claim 7, characterized in that: The lower expansion arm (32) is a rotating roller, and drill teeth (321) are evenly distributed on the circumferential surface of the rotating roller.

9. The variable diameter mixing drill bit for cement soil inclined pile construction according to claim 7, characterized in that: The bottom end of the sliding drill rod (2) is provided with a mounting cavity (26), and the torque output assembly comprises a driving shaft (251) rotatably arranged in the sliding drill rod (2), arc-shaped blades (252) are arranged on the circumferential surface of the driving shaft (251) along its circumference, and the bottom end of the driving shaft (251) extends into the mounting cavity (26) and is drivingly connected to the universal joint (24).

10. A variable diameter mixing drill bit for cement soil inclined pile construction according to claim 9, characterized in that: A driving bevel gear (253) is disposed at the bottom end of the driving shaft (251), and a driven bevel gear (254) meshing with the driving bevel gear (253) is disposed at the inner end of the universal joint (24).

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