Bottom-expanded pile drill bit with adjustable bottom-expanded width, bottom-expanded width adjusting method and bottom-expanded pile construction method

Abstract

The invention provides a pedestal pile drill bit with the adjustable pedestal width, a pedestal width adjusting method and a pedestal pile construction method. The pedestal pile drill bit comprises a first rod body, a second rod body, a first connecting rod, a second connecting rod, a third connecting rod and a mud cutting plate with a blade. The first rod body, the first connecting rod, the second connecting rod and the mud cutting plate form a parallelogram linkage mechanism; when the second rod body reciprocates in the hollow structure of the first rod body in the axial direction, the third connecting rod is driven to push and pull the parallelogram linkage mechanism, the mud cutting plate moves inwards and outwards, and therefore the base expanding width change is achieved. The expanded-base pile drill bit is simple in structure, and the expanded-base width is adjusted by adjusting the connecting positions of the first connecting rod and the second connecting rod on the mud cutting plate. When the underreaming pile drill bit is used for underreaming pile construction, the construction efficiency is high, the underreaming process is simple and controllable, and the adaptability and quality of underreaming pile construction can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of drilling machinery and equipment for engineering, and particularly relates to an under-reamed pile bit with adjustable under-reaming width, an under-reaming width adjustment method, and an under-reamed pile construction method. Background Art

[0002] With the acceleration of the urbanization process, the number of construction projects is increasing day by day. As a form of building foundation, pile foundations are widely used in engineering construction.

[0003] The under-reamed pile is an improved pile structure, the bottom diameter of which is larger than the upper pile body diameter, and the bearing capacity of a single pile is greatly improved compared with that of a straight pile with the same pile body diameter. At present, the under-reamed pile mainly adopts two methods of manual hole digging or mechanical hole forming to ream the bottom of the pile. The manual hole digging method has low efficiency and poor safety, and does not meet the requirements of modern construction. Although the mechanical hole forming efficiency has been improved, there are currently few types of under-reaming bits, and the under-reaming width of most bits is fixed and non-adjustable, resulting in a complex under-reaming process, difficult control of the under-reaming width, and being not conducive to the popularization and application of under-reamed piles. Summary of the Invention

[0004] In view of the above technical status quo, the present invention provides an under-reamed pile bit with adjustable under-reaming width, which has the advantages of simple structure, easy operation, and easy adjustment of the under-reaming width.

[0005] The technical solution provided by the present invention is: an under-reamed pile bit with adjustable under-reaming width, including a first rod body, a second rod body, and a linkage assembly;

[0006] The linkage assembly includes a first connecting rod, a second connecting rod, a third connecting rod, and a mud-cutting plate with a blade;

[0007] The first rod body is provided with a hollow structure inside. One end of the first rod body is an open end that can communicate with the hollow structure, and the side wall of the first rod body is provided with an opening communicating with the hollow structure, denoted as the side wall opening;

[0008] One end of the second rod body is connected to a rotary drilling rig, and the other end extends into the hollow structure through the open end of the first rod body;

[0009] Along the axial direction parallel to the first rod, position A and position B are set on the first rod, position a and position b are set on the mud cutting plate. One end of the first connecting rod is movably connected to position A, and the other end is movably connected to position a. One end of the second connecting rod is movably connected to position B, and the other end is movably connected to position b. The first rod, the first connecting rod, the second connecting rod, and the mud cutting plate form a parallelogram linkage mechanism, that is, the included angle between the first rod and the first connecting rod (denoted as angle M) is equal to the included angle between the first rod and the second connecting rod (denoted as angle N), and the distance between position A and position a (denoted as distance X) is equal to the distance between position B and position b (denoted as distance Y); the position a is adjustable, and the position b is adjustable;

[0010] One end of the third connecting rod passes through the side wall opening and is movably connected to the second rod, and the other end is movably connected between the two ends of the first connecting rod;

[0011] When the rotary drill works, it can drive the second rod to reciprocate along the axial direction of the first rod inside the hollow structure. Through the side wall opening, it can drive the third connecting rod to push or pull the parallelogram mechanism, so that the parallelogram mechanism is linked, that is, angle N and angle M change synchronously (the change trends are the same and the change amounts are the same), thereby driving the distance between the cutting edge and the first rod (i.e., the under-reaming width) to increase or decrease.

[0012] The under-reaming width refers to the distance between the cutting edge and the first rod.

[0013] The movable connection method is not limited, such as hinged connection, etc.

[0014] As a realization method, a first protrusion is provided on the first rod, and the first protrusion is movably connected to the first connecting rod, and the connection position is the position A. The structure of the first protrusion is not limited, such as a plate-like structure connected to the first rod, etc.

[0015] As a realization method, a second protrusion is provided on the first rod, and the second protrusion is movably connected to the second connecting rod, and the connection position is the position B. The structure of the second protrusion is not limited, such as a plate-like structure connected to the first rod, etc.

[0016] As a realization method, a third protrusion is provided on the second rod, and the third protrusion passes through the side wall opening. One end of the first connecting rod is movably connected to the third protrusion. When the second rod reciprocates along the axial direction of the first rod inside the hollow structure, the third protrusion drives the third connecting rod to push or pull the parallelogram mechanism through the side wall opening. The structure of the third protrusion is not limited, such as a plate-like structure connected to the second rod, etc.

[0017] Preferably, one end of the first connecting rod is movably connected to the first protrusion through a pin hole and a pin.

[0018] As an implementation, the other end of the first connecting rod is connected to position a of the mud cutting plate through a first connecting member. Preferably, the first connecting member is a first bolt and a first nut, a first groove is provided on the mud cutting plate, and the first nut can be displaced in the first groove. By adjusting the position of the first nut in the first groove, the fixed position a of the other end of the first connecting rod on the mud cutting plate can be adjusted.

[0019] As an implementation, the other end of the second connecting rod is connected to position b of the mud cutting plate through a second connecting member. Preferably, the second connecting member is a second bolt and a second nut, a second groove is provided on the mud cutting plate, and the second nut can be displaced horizontally in the second groove. By adjusting the position of the second nut in the first groove, the fixed position b of the other end of the first connecting rod on the mud cutting plate can be adjusted.

[0020] Preferably, there are two sets of the linkage components, denoted as the first linkage component and the second linkage component. The structures of the first linkage component and the second linkage component are the same. The first linkage component and the second linkage component are in a central axisymmetric structure with the first rod body as the axis, that is, the first linkage component coincides with the second linkage component after rotating 180° around the first rod body.

[0021] The setting position of the cutting edge on the mud cutting plate should be beneficial to the contact between the cutting edge and the soil, so as to improve the cutting efficiency of the soil. Preferably, it is set at the edge of the mud cutting plate.

[0022] Preferably, the plate surface of the mud cutting plate is in a trapezoidal structure, including a short side and a long side that are parallel to each other. The side in contact with the soil during soil cutting is the short side, which is beneficial to the cutting effect. As a further preference, a plurality of pick teeth are provided on the side of the mud cutting plate in contact with the soil for tunneling hard soil or gravel.

[0023] Preferably, the plate surface of the mud cutting plate is inclined towards the barrel body, which is beneficial to guiding the cut soil blocks into the interior of the barrel body.

[0024] In the present invention, the method for adjusting the under-reaming width of the under-reaming pile bit includes the following steps:

[0025] (A) Loosen the connection between the first connecting rod and the mud cutting plate at position a, and loosen the connection between the second connecting rod and the mud cutting plate at position b; adjust the position of the mud cutting plate so that the under-reaming width is a preset value;

[0026] (B) Push the second rod body to move downward along the axis inside the hollow structure, push the third connecting rod downward, and the parallelogram linkage rotates until the angle M is maximized. At this time, the contact position between the end of the first connecting rod and the mud cutting plate is position a, and the contact position between the end of the second connecting rod and the mud cutting plate is position b. The end of the first connecting rod is movably connected to position a of the mud cutting plate through the first connecting member, and the end of the first connecting rod is movably connected to position b of the mud cutting plate through the second connecting member.

[0027] Preferably, driven by the second rod body, the third connecting rod can push the parallelogram linkage to rotate so that the maximum angle M is 90°.

[0028] When using this under-reamed bit for under-reamed pile construction, the following steps are included:

[0029] (1) The rotary drilling rig works, and the drill bit drills to the pile bottom elevation to form a pile bottom bell.

[0030] (2) Replace the drill bit of the rotary drilling rig in step (1) with the under-reamed pile bit with adjustable under-reamed width of the present invention; set the under-reamed width according to the soil quality, and adjust the under-reamed width of the under-reamed pile bit with adjustable under-reamed width to the set under-reamed width.

[0031] (3) The rotary drilling rig works, and continues to drill and cut the soil mass in the pile bottom bell. During this process, the second rod body moves downward along the axis of the first rod body inside the hollow structure, pushes the third connecting rod downward, and the parallelogram linkage rotates until the angle M is maximized to reach the set under-reamed width, so that the under-reamed section is formed.

[0032] Preferably, the following step (4) is carried out after step (3):

[0033] (4) Clear the hole and change the slurry, lower the steel reinforcement cage, and pour concrete to complete the pile foundation construction.

[0034] Preferably, the under-reamed pile bit with adjustable under-reamed width further includes a barrel body. The first rod body is located inside the barrel body. The upper end of the barrel body is provided with an upper end cover, and the lower end is provided with a lower end cover. The upper end cover is provided with an opening, denoted as the upper end cover opening. The other end of the second rod body passes through the upper end cover opening and the open end of the first rod body and extends into the hollow structure. The barrel wall is provided with an opening, denoted as the barrel wall opening. When the under-reamed width increases, the mud cutting plate can extend out of the barrel body through the barrel wall opening; when the cutting teeth cut the soil mass at the pile bottom, the soil mass is cut into small pieces and discharged, and the soil blocks enter the inner cavity of the barrel body along the surface of the mud cutting plate and are stored in the whole body. Further preferably, the lower end cover can be opened and closed. When the drill bit stops working and the barrel body is moved to the set position, the lower end cover is opened, and the soil can be poured out of the barrel body, so that the operation of taking soil and transporting soil at the pile bottom can be realized.

[0035] As an implementation, one end of the lower end cover is hinged to the barrel wall, and the other end is provided with a locking structure for opening and closing the lower end cover. The locking mechanism can be a structure such as a bolt.

[0036] When the under-reaming pile drill bit with adjustable under-reaming width includes a barrel, the method for adjusting the under-reaming width of the under-reaming pile drill bit comprises the following steps:

[0037] (A) Loosen the connection between the first connecting rod and the mud cutting plate at position a, and loosen the connection between the second connecting rod and the mud cutting plate at position b; adjust the position of the mud cutting plate so that it extends out of the opening of the barrel wall, and the under-reaming width is a preset value;

[0038] (B) Push the second rod body to move along the axis towards the bottom of the pile inside the hollow structure. The second rod body drives the third connecting rod to push the parallelogram linkage to rotate, so that the angle M increases from the initial value to the maximum. At this time, the contact position between the end of the first connecting rod and the mud cutting plate is position a, and the contact position between the end of the second connecting rod and the mud cutting plate is position b. The end of the first connecting rod is movably connected to the mud cutting plate at position a through the first connecting piece, and the end of the first connecting rod is movably connected to the mud cutting plate at position b through the second connecting piece.

[0039] Preferably, driven by the second rod body, the third connecting rod can push the parallelogram linkage to rotate so that the maximum value of the angle M is 90°.

[0040] When the under-reaming pile drill bit with adjustable under-reaming width includes a barrel, when using this under-reaming drill bit for under-reaming pile construction, it comprises the following steps:

[0041] (1) The rotary drilling rig works, and the drill bit drills to the bottom elevation of the pile to form a pile bottom conical cap;

[0042] (2) Replace the drill bit of the rotary drilling rig in step (1) with the under-reaming pile drill bit with adjustable under-reaming width of the present invention; set the under-reaming width according to the soil quality, and adjust the under-reaming width of the under-reaming pile drill bit with adjustable under-reaming width to the set under-reaming width;

[0043] (3) The rotary drilling rig works, continues to drill and cut the soil body in the pile bottom conical cap, and the chopped soil blocks enter the barrel along the mud cutting plate. During this process, the second rod body moves downward along the axis inside the hollow structure, pushes the third connecting rod downward, and the parallelogram linkage rotates to the maximum angle M to reach the set under-reaming width, so that the under-reaming section is formed.

[0044] Preferably, the lower end cover is openable and closable. In step (2), when the chopped soil blocks enter the barrel along the mud cutting plate, the monitoring of the accumulation of soil blocks is started;

[0045] The monitoring of the accumulation of soil blocks is as follows: Monitor the soil blocks in the bucket body. When a certain amount of soil blocks accumulates in the bucket body, the rotary drilling rig stops working, the bucket body is lifted, the lower cover plate is opened, and the soil blocks inside the bucket body are discharged; then the rotary drilling rig works and continues to drill and cut the soil in the pile bottom bonnet.

[0046] Preferably, the following step (4) is carried out after step (3):

[0047] (4) Clear the hole and replace the slurry, lower the steel reinforcement cage, and pour concrete to complete the construction of the pile foundation.

[0048] Compared with the prior art, the present invention uses a first rod body, a first connecting rod, a second connecting rod and a mud cutting plate to form a parallelogram linkage mechanism. When the second rod body moves linearly back and forth along the axial direction of the first rod body in the hollow structure of the first rod body, it drives the third connecting rod to push and pull the parallelogram linkage mechanism, realizing the inward and outward movement of the mud cutting plate, so as to realize the change of the bottom expansion width, and has the following beneficial effects:

[0049] (1) The present invention can realize the adjustment of the bottom expansion width by adjusting the connection positions of the first connecting rod and the second connecting rod on the mud cutting plate. The adjustment method is simple and easy to implement;

[0050] (2) When using the bottom expansion drill bit of the present invention for the construction of a bottom expansion pile, the rotary drilling rig is used to drive the second rod body to move towards the pile bottom direction, and the mud cutting plate automatically unfolds and cuts the soil under the drive of the first rod body, so as to realize the formation of the bottom expansion;

[0051] (3) The present invention preferably sets a bucket body around the drill bit, and sets an opening on the bucket wall through which the mud cutting plate can enter and exit. When the drill rig works, the cutting edge of the mud cutting plate extends out of the bucket body, and the cut soil can enter the inside of the bucket body along the mud cutting plate for storage. When it is further preferably that the lower end cover of the bucket body can be opened and closed, after the bucket body is transported to the set position, the lower end cover is opened to quickly unload the soil, avoiding manual cleaning operations, and the bucket body has a large volume and strong soil transportation capacity, improving the work efficiency;

[0052] (4) The present invention has a simple structure, simple operation, high construction efficiency, easy processing and assembly, and the key components do not require special materials, with low manufacturing cost, which is conducive to the popularization and application of bottom expansion piles. Moreover, the bottom expansion diameter can be flexibly adjusted, and the bottom expansion process is simple and controllable, which can improve the adaptability and quality of the construction of bottom expansion piles and promote their application in engineering construction. Description of the Drawings

[0053] Figure 1 It is a schematic structural diagram of a bottom expansion pile drill bit with adjustable bottom expansion width in Embodiment 1 of the present invention.

[0054] Figure 2 It is Figure 1 a schematic side structure diagram of the first rod body in

[0055] Figure 3 It is a schematic structural diagram before the second rod body descends in the hollow structure;

[0056] Figure 4 It is a schematic structural diagram after the second rod body descends in the hollow structure;

[0057] Figure 5 It is a schematic structural diagram of the under-reamed pile bit with adjustable under-reaming width in Embodiment 2 of the present invention.

[0058] Figure 6 It is Figure 5 a schematic structural diagram of one side of the middle barrel body;

[0059] Figure 7 It is a bottom-up structural sectional view of the barrel body when the second rod body descends in the hollow structure.

[0060] Attached Figures 1-7 The reference numerals in

[0061] are: 10 - the first rod body, 11 - the hollow structure, 12 - the side wall opening, 13 - the first protrusion, 14 - the second protrusion;

[0062] 20 - the second rod body, 21 - the third protrusion;

[0063] 30 - the first connecting rod;

[0064] 40 - the second connecting rod;

[0065] 50 - the third connecting rod;

[0066] 60 - the mud cutting plate, 61 - the blade, 62 - the pick, 63 - the first groove, 64 - the second groove;

[0067] 70 - the barrel body, 71 - the upper end cover, 72 - the lower end cover, 73 - the upper end cover opening, 74 - the barrel wall opening, 75 - the hinge, 76 - the lock. Detailed implementation manners

[0068] The present invention will be further described in detail below in conjunction with embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention, and any non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0069] In the present invention, words such as "including" and "comprising" should be interpreted as having an inclusive meaning rather than an exclusive or exhaustive meaning; that is, it means "including but not limited to".

[0070] In the present invention, the use of "first", "second" and other similar terms is only for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0071] Embodiment 1:

[0072] As Figures 1-4 shown, the under-reamed pile bit with adjustable under-reamed width includes a first rod body 10, a second rod body 20 and a linkage assembly.

[0073] The linkage assembly includes a first connecting rod 30, a second connecting rod 40, a third connecting rod 50 and a mud-cutting plate 60 with blades 61.

[0074] A hollow structure 11 is arranged inside the first rod body 10. One end of the first rod body 10 is an open end that can communicate with the hollow structure 11, and an opening communicating with the hollow structure 11 is arranged on the side wall of the first rod body 10, denoted as side wall opening 12.

[0075] One end of the second rod body 20 is connected to a rotary drilling rig, and the other end extends into the hollow structure 11 through the open end of the first rod body 10.

[0076] Along the direction parallel to the axis of the first rod body, position A and position B are set on the first rod body, position a and position b are set on the mud-cutting plate. One end of the first connecting rod 30 is movably connected to position A, and the other end is movably connected to position a. One end of the second connecting rod 40 is movably connected to position B, and the other end is movably connected to position b; the first rod body 10, the first connecting rod 30, the second connecting rod 40 and the mud-cutting plate 60 form a parallelogram linkage mechanism, that is, the included angle (denoted as angle M) between the first rod 10 and the first connecting rod 30 is equal to the included angle (denoted as angle N) between the first rod body 10 and the second connecting rod 40, and the distance (denoted as distance X) between position A and position a is equal to the distance (denoted as distance Y) between position B and position b. And, position a is adjustable, and said position b is adjustable.

[0077] One end of the third connecting rod 50 passes through the side wall opening 12 and is movably connected to the second rod body 20, and the other end is movably connected between the two ends of the first connecting rod 10.

[0078] As Figure 3 , 4 shown, when the rotary drilling rig works, it can drive the second rod body 20 to make a linear reciprocating motion along the axis of the first rod body inside the hollow structure 11, and through the side wall opening 12, it can drive the third connecting rod 50 to push or pull the parallelogram linkage mechanism to make it move, that is, angle N and angle M change synchronously (the change trends are the same and the change amounts are the same), so as to drive the distance between the blade 61 and the first rod body 10 (i.e., the under-reamed width) to increase or decrease.

[0079] In this embodiment, a first protrusion 13 and a second protrusion 14 are provided on the first rod 10. The first protrusion 13 is hinged to the first connecting rod 30, and the connection position is position A. The second protrusion 14 is hinged to the second connecting rod 4, and the connection position is position B. In this embodiment, the first protrusion is a plate-like structure fixedly connected to the first rod, and the second protrusion is a plate-like structure fixedly connected to the first rod.

[0080] In this embodiment, a third protrusion 21 is provided on the second rod 20. The third protrusion 21 passes through the side wall opening 12. One end of the first connecting rod 30 is hinged to the third protrusion 21. When the second rod 20 reciprocates axially inside the hollow structure 11, the third protrusion 21 drives the third connecting rod through the side wall opening to push or pull the parallelogram mechanism. In this embodiment, the third protrusion is a plate-like structure fixedly connected to the second rod.

[0081] In this embodiment, one end of the first connecting rod 30 is movably connected to the first protrusion 13 through a pin hole and a pin, and the other end of the first connecting rod 30 is fixedly connected to position a of the mud cutting plate through a first bolt and a first nut. One end of the second connecting rod 40 is movably connected to the first protrusion 14 through a pin hole and a pin, and the other end of the second connecting rod 40 is fixedly connected to position b of the mud cutting plate through a second bolt and a second nut.

[0082] In this embodiment, a first groove 63 and a second groove 64 are provided on the mud cutting plate 60. The first nut can be displaced in the first groove 63. By adjusting the position of the first nut in the first groove 63, the fixed position a of the other end of the first connecting rod 30 on the mud cutting plate 60 can be adjusted. The second nut can be displaced in the second groove 64. By adjusting the position of the second nut in the second groove 64, the fixed position b of the other end of the second connecting rod 40 on the mud cutting plate 60 can be adjusted.

[0083] In this embodiment, there are two sets of linkage components, denoted as the first linkage component and the second linkage component. The structures of the first linkage component and the second linkage component are the same, and the first linkage component and the second linkage component are symmetrically structured about the first rod 10 as the axis.

[0084] In this embodiment, the cutting edge 61 is provided at the edge of the mud cutting plate 60.

[0085] In this embodiment, the method for adjusting the bottom expansion width of the under-reamed pile bit includes the following steps:

[0086] (A) Loosen the connection between the first connecting rod 30 and the mud cutting plate 60 at position a, and loosen the connection between the second connecting rod 40 and the mud cutting plate 60 at position b; adjust the position of the mud cutting plate so that the bottom expansion width is a preset value;

[0087] (B) Angle M is at its initial value; the second rod 20 is pushed to move along the axis inside the hollow structure 11 towards the bottom of the pile, and the second rod 20 drives the third connecting rod 50 to push the parallelogram linkage to rotate, increasing angle M from the initial value to the maximum. At this time, the contact position of the end of the first connecting rod 30 with the mud cutting plate 60 is position a, and the contact position of the end of the second connecting rod 20 with the mud cutting plate 60 is position b. The end of the first connecting rod 30 is movably connected to position a of the mud cutting plate 60 through the first bolt and the first nut, and the end of the second connecting rod 40 is movably connected to position b of the mud cutting plate 60 through the second bolt and the second nut.

[0088] In this embodiment, driven by the second rod, the third connecting rod 50 can push the parallelogram linkage to rotate so that the maximum value of angle M is 90°.

[0089] When using this under-reamed bit for under-reamed pile construction, the following steps are included:

[0090] (1) The bit of the rotary drilling rig uses a common bit. The rotary drilling rig works, and the bit drills to the bottom elevation of the pile to form a pile bottom conical cap.

[0091] (2) Replace the bit in step (1) with the under-reamed pile bit with adjustable under-reamed width in this embodiment; set the under-reamed width according to the soil quality, and adjust the under-reamed width of the under-reamed pile bit with adjustable under-reamed width to the set under-reamed width through the above steps (A) and (B).

[0092] (3) The rotary drilling rig works, and continues to drill and cut the soil in the pile bottom conical cap. During this process, the second rod moves downward along the axis of the first rod inside the hollow structure, pushing the third connecting rod downward, and the parallelogram linkage rotates until angle M reaches the maximum to the set under-reamed width, forming the under-reamed section and cleaning the soil blocks.

[0093] (4) Clear the hole and change the slurry, lower the steel reinforcement cage, and pour concrete to complete the pile foundation construction.

[0094] Embodiment 2:

[0095] In this embodiment, the under-reamed pile bit with adjustable under-reamed width is basically the same as that in the embodiment. The difference is that as shown in Figure 5 、 6 , the under-reamed pile bit further includes a barrel body 70. The first rod 10 is located inside the barrel body 70. The upper end of the barrel body 70 is provided with an upper end cover 71, and the lower end is provided with a lower end cover 72. The upper end cover 71 is provided with an opening, denoted as the upper end cover opening 73. The other end of the second rod 20 passes through the upper end cover opening 73 and the open end of the first rod 10 and extends into the hollow structure 11. The barrel wall is provided with an opening, denoted as the barrel wall opening 74. When the under-reamed width of the under-reamed pile bit increases, as shown in Figure 7 , the mud cutting plate 60 can extend out of the barrel body 70 through the barrel wall opening 74.

[0096] In this embodiment, the lower end cover 72 can be opened and closed. One end of the lower end cover is hinged to the barrel wall through a hinge member 75, and a latch 76 is provided at the other end for opening and closing the lower end cover 72. In this embodiment, the latch is a bolt structure.

[0097] In this embodiment, when the cutting teeth 61 cut the soil at the bottom of the pile, the soil is cut into small pieces and discharged. The soil blocks enter the inner cavity of the barrel along the surface of the mud cutting plate and are stored in the barrel 70. When the drill bit stops working, the barrel 70 is moved to a set position, the lower end cover 72 is opened, and the soil can be poured out of the barrel 70, so that the operation of taking soil and transporting soil at the bottom of the pile can be realized.

[0098] In this embodiment, the cutting edge is provided at the edge of the mud cutting plate. The plate surface of the mud cutting plate is in a trapezoidal structure, including a short side and a long side that are parallel to each other. The side in contact with the soil during soil cutting is the short side, which is beneficial to the cutting effect. As a further preference, a plurality of pick teeth 62 are provided on the side of the mud cutting plate in contact with the soil for tunneling hard soil or crushed stones.

[0099] In this embodiment, the method for adjusting the under-reaming width of the under-reamed pile drill bit includes the following steps:

[0100] (a) Loosen the connection between the first connecting rod 30 and the mud cutting plate 60 at position a, and loosen the connection between the second connecting rod 40 and the mud cutting plate 60 at position b; adjust the position of the mud cutting plate so that it extends out of the opening of the barrel wall, and the under-reaming width is a preset value;

[0101] (b) Push the second rod body 20 to move along the axis towards the bottom of the pile inside the hollow structure 11. The second rod body 20 drives the third connecting rod 50 to push the parallelogram linkage to rotate, so that the angle M increases from the initial value to the maximum. At this time, the contact position of the end of the first connecting rod 30 with the mud cutting plate 60 is position a, and the contact position of the end of the second connecting rod 20 with the mud cutting plate 60 is position b. The end of the first connecting rod 30 is movably connected to the mud cutting plate 60 at position a through a first bolt and a first nut, and the end of the second connecting rod 40 is movably connected to the mud cutting plate 60 at position b through a second bolt and a second nut.

[0102] In this embodiment, driven by the second rod body, the third connecting rod 50 can push the parallelogram linkage to rotate so that the maximum value of the angle M is 90°.

[0103] When using this under-reaming drill bit for under-reamed pile construction, it includes the following steps:

[0104] (1) The drill bit of the rotary drilling rig uses an ordinary drill bit. The rotary drilling rig works, and the drill bit drills to the bottom elevation of the pile to form a pile bottom conical cap;

[0105] (2) Replace the drill bit in step (1) with the under-reamed pile drill bit with adjustable under-reamed width in this embodiment; set the under-reamed width according to the soil quality, and adjust the under-reamed width of the under-reamed pile drill bit with adjustable under-reamed width to the set under-reamed width through the above steps (a) and (b);

[0106] (3) The rotary drilling rig works, continues to drill and cut the soil in the pile bottom bonnet, the chopped soil blocks enter the barrel body along the mud cutting plate, start the monitoring of soil block accumulation. During this process, the second rod moves downward along the axis inside the hollow structure, pushes the third connecting rod downward, and the parallelogram linkage rotates;

[0107] The monitoring of soil block accumulation is: monitoring the soil blocks in the barrel body. When a certain amount of soil blocks accumulates in the barrel body, the rotary drilling rig stops working, lifts the barrel body, opens the lower cover plate, and discharges the soil blocks inside the barrel body; then the rotary drilling rig works and continues to drill and cut the soil in the pile bottom bonnet;

[0108] When the parallelogram linkage rotates to the maximum angle M and reaches the set under-reamed width, the under-reamed section is formed.

[0109] (4) Clear the hole and change the slurry, lower the steel reinforcement cage, and pour concrete to complete the pile foundation construction.

[0110] The above embodiments have described the technical solutions of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, supplements or similar replacements made within the scope of the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A bottom-enlarging pile drill bit with adjustable bottom-enlarging width, characterized by: It includes a first rod body, a second rod body and a linkage assembly; The linkage assembly comprises a first connecting rod, a second connecting rod, a third connecting rod and a mud cutting board with a blade; A hollow structure is arranged inside the first rod body, one end of the first rod body is an open end that can be connected to the hollow structure, and a side wall of the first rod body is arranged with an opening that can be connected to the hollow structure, which is recorded as a side wall opening; One end of the second rod body is connected to the rotary drill, and the other end extends into the hollow structure through the opening end of the first rod body; Along the axial direction parallel to the first rod body, positions A and B are set on the first rod body, positions a and b are set on the mud cutting board, one end of the first connecting rod is movably connected to position A, and the other end is movably connected to position a, one end of the second connecting rod is movably connected to position B, and the other end is movably connected to position b, and the first rod body, the first connecting rod, the second connecting rod and the mud cutting board form a parallelogram linkage mechanism; The position a is adjustable, and the position b is adjustable; One end of the third connecting rod passes through the side wall opening and is movably connected to the second rod body, and the other end is movably connected between the two ends of the first connecting rod; When the rotary drilling rig is working, the second rod body reciprocates along the axial direction of the first rod body inside the hollow structure, and can drive the third connecting rod to push or pull the parallelogram mechanism through the side wall opening, so that the parallelogram mechanism is linked, thereby driving the bottom expansion width to increase or decrease.

2. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 1, characterized in that: A first protrusion is provided on the first rod body, and the first protrusion is fixedly connected to the first connecting rod, and the connection position is position A; A second protrusion is provided on the first rod body, and the second protrusion is fixedly connected to the second connecting rod, and the connection position is position B.

3. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 1, characterized in that: A third protrusion is provided on the second rod body, and the third protrusion passes through the side wall opening. One end of the first connecting rod is movably connected to the third protrusion. When the second rod body reciprocates along the axial direction of the first rod body inside the hollow structure, the third protrusion drives the third connecting rod to push or pull the parallelogram mechanism through the side wall opening.

4. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 1, characterized in that: The other end of the first connecting rod is fixedly connected to the position a of the mud cutting plate through a first bolt and a first nut; a first groove is provided on the mud cutting plate, and the first nut can be displaced in the first groove, and the fixed position a of the other end of the first connecting rod on the mud cutting plate can be adjusted by adjusting the position of the first nut in the first groove; The other end of the second connecting rod is fixedly connected to the position b of the mud cutting plate by a second bolt and a second nut; a second groove is arranged on the mud cutting plate, and the second nut can be laterally displaced in the second groove. By adjusting the position of the second nut in the first groove, the other end of the first connecting rod can be adjusted to the fixed position b of the mud cutting plate.

5. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 1, characterized in that: The linkage components are two sets, which are recorded as a first linkage component and a second linkage component. The first linkage component and the second linkage component have the same structure and are symmetrical about the first rod body.

6. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 1, characterized in that: The bottom expansion pile drill with adjustable bottom expansion width also includes a barrel body, the first rod body is located inside the barrel body, an upper end cover is provided at the upper end of the barrel body, and a lower end cover is provided at the lower end. The upper end cover is provided with an opening, which is recorded as the upper end cover opening. The other end of the second rod body passes through the upper end cover opening and the open end of the first rod body and extends into the hollow structure. An opening is provided on the barrel wall, which is recorded as the barrel wall opening. When the bottom expansion width increases, the mud cutting plate can extend out of the barrel body through the barrel wall opening.

7. The bottom-enlarged pile drill bit with adjustable bottom-enlarged width as claimed in claim 6, characterized in that: The lower end cover can be opened and closed.

8. The method for adjusting the bottom width of a bottom-enlarged pile drill bit according to any one of claims 1 to 5, characterized in that: The steps include: (A) Loosen the connection between the first connecting rod and the mud cutting board at position a, and loosen the connection between the second connecting rod and the mud cutting board at position b; adjust the position of the mud cutting board so that the bottom expansion width is a preset value; (B) Push the second rod body to move downward along the axis inside the hollow structure, push the third connecting rod downward, and the parallelogram linkage mechanism rotates to the maximum angle M. At this time, the contact position between the end of the first connecting rod and the mud cutting board is position a, and the contact position between the end of the second connecting rod and the mud cutting board is position b. The end of the first connecting rod is movably connected to the position a of the mud cutting board through the first connecting member, and the end of the first connecting rod is movably connected to the position b of the mud cutting board through the second connecting member.

9. The method for adjusting the bottom width of a bottom-enlarged pile drill bit according to claim 6 or 7, characterized in that: The steps include: (A) Loosen the connection between the first connecting rod and the mud cutting board at position a, and loosen the connection between the second connecting rod and the mud cutting board at position b; adjust the position of the mud cutting board so that it extends out of the barrel wall opening and the bottom expansion width is a preset value; (B) Push the second rod body to move along the axis toward the bottom of the pile inside the hollow structure. The second rod body drives the third connecting rod to push the parallelogram linkage mechanism to rotate, so that the angle M increases from the initial value to the maximum. At this time, the contact position between the end of the first connecting rod and the mud cutting board is position a, and the contact position between the end of the second connecting rod and the mud cutting board is position b. The end of the first connecting rod is movably connected to the position a of the mud cutting board through the first connecting member, and the end of the first connecting rod is movably connected to the position b of the mud cutting board through the second connecting member.

10. A method for constructing a base-enlarged pile using the base-enlarged pile drill bit according to any one of claims 1 to 5, characterized in that: The steps include: (1) The rotary drilling rig works, and the drill bit drills to the pile bottom elevation to form a pile bottom bucket; (2) using the bottom-enlarging pile drill bit with adjustable bottom-enlarging width to replace the drill bit of the rotary drilling rig in step (1); setting the bottom-enlarging width according to the soil quality, and adjusting the bottom-enlarging width of the bottom-enlarging pile drill bit with adjustable bottom-enlarging width to the set bottom-enlarging width; (3) The rotary drilling rig continues to drill into and cut the soil in the bucket at the bottom of the pile. During this process, the second rod moves downward along the axis of the first rod inside the hollow structure, pushing the third connecting rod downward. The parallelogram linkage mechanism rotates to the maximum angle M to achieve the set bottom expansion width, so that the bottom expansion section is formed.

11. A method for constructing a base-enlarged pile using the base-enlarged pile drill bit according to claim 6 or 7, characterized in that: The steps include: When the bottom enlargement drill bit is used to carry out the bottom enlargement pile construction, the following steps are included: (1) The rotary drilling rig works, and the drill bit drills to the pile bottom elevation to form a pile bottom bucket; (2) using the bottom-enlarging pile drill bit with adjustable bottom-enlarging width to replace the drill bit of the rotary drilling rig in step (1); setting the bottom-enlarging width according to the soil quality, and adjusting the bottom-enlarging width of the bottom-enlarging pile drill bit with adjustable bottom-enlarging width to the set bottom-enlarging width; (3) The rotary drilling rig continues to drill into the soil in the bucket at the bottom of the pile, and the chopped soil enters the barrel along the mud cutting plate. During this process, the second rod moves downward along the axis inside the hollow structure, pushing the third connecting rod downward, and the parallelogram linkage mechanism rotates to the maximum angle M to reach the set bottom expansion width, so that the bottom expansion section is formed.

Images