A hole collapse prevention construction device and cast-in-place pile construction technology

Abstract

The present application relates to the technical field of highway construction, and in particular to a construction device for preventing hole collapse and a construction process for bored piles, comprising a drill rod and a rotary drill bit, wherein the rotary drill bit is fixedly connected to the suspended end of the drill rod, and further comprising a sleeve, at least two sets of connecting rods, a lifting assembly and a supporting assembly, wherein the sleeve is concentrically arranged with the drill rod, one end of the connecting rod is connected to the inner wall of the sleeve, and the other end is rotatably connected to the drill rod, and the supporting assembly comprises a collar, a plurality of tie rods, a plurality of supporting rods and a diameter expansion member, one end of the supporting rod is rotatably connected to the sleeve, one end of the tie rod is rotatably connected to the supporting rod, and the other end is rotatably connected to the collar, and the collar is slidably connected to the sleeve, and the horizontal projection diameter of the rotary drill bit is smaller than the inner diameter of the casing. Through the synchronous movement of the rotary drill bit and the casing, the casing supports the wall of the pile hole, so that the wall of the pile hole is in a protective state, and at the same time, through the synchronous action of the lifting assembly and the rotary drill bit, the efficiency of rotary drilling of the pile hole is improved, thereby improving the construction efficiency of the bored pile.

Description

Technical Field

[0001] The present application relates to the technical field of highway construction, and in particular to a hole collapse prevention construction device and a cast-in-place pile construction process. Background Art

[0002] In highway construction, in sections prone to collapse or elevated construction sections, it is often necessary to improve the support performance of the highway by pouring concrete piles. During the pouring process of concrete piles: first, lay out the line and locate the position of the pile hole; second, set the casing; third, drill and take soil; fourth, place the steel cage; finally, pour the pile into shape to realize the processing of the pile. At present, during the construction of the pile, the rotary drilling rig is used to drill and take soil to ensure the efficiency and safety of the construction process of the pile.

[0003] The Chinese patent application number 201711397918.4 discloses a method for drilling a bored pile with a rotary drill sleeve, which includes the following steps: Step 1: Construction preparation, including the production of a steel cage, measurement and positioning, and sleeve design and production; Step 2: The rotary drill rig is in place, and the rotary drill rig is used to drive the sleeve to rotate through the sleeve connector to follow up the construction; Step 3: Replace the drill bit; Step 4: Take soil from the sleeve and drill to the designed elevation; Step 5: Hole formation detection; Step 6: Clean the hole and check the thickness of the sediment; Step 7: Place the steel cage and the guide tube; Step 8: Check the thickness of the sediment and clean the hole for the second time; Step 9: Underwater concrete pouring; Step 10: Pull out the sleeve with the rotary drill; Step 11: Hole formation.

[0004] In view of the above-mentioned related technologies, the applicant believes that after the sleeve is buried, it is necessary to remove the pin connecting the sleeve connector and the drill rod, and then install the rotary drilling drill barrel, and then drill and extract soil through the rotary drilling drill barrel, which affects the efficiency of rotary drilling of the pile hole and the construction efficiency of the cast-in-place pile. Summary of the invention

[0005] In order to improve the construction efficiency of bored piles, the present application provides a hole collapse prevention construction device and a bored pile construction process.

[0006] In the first aspect, the present application provides a construction device for preventing hole collapse, which adopts the following technical solution:

[0007] The cam is connected to the drill bit by the spring, and the cam is connected to the drill bit by the spring, so that the drill bit can be directly connected to the casing and the casing can be directly connected to the casing by the spring.

[0008] By adopting the above technical scheme, when the pile hole is rotary drilled, first, force is applied to the collar, the collar drives the pull rod to move, the pull rod drives the support rod to move, and when multiple support rods are located in the same plane, the first section of casing is installed on the support rod; then the drill rod is adjusted, the drill rod drives the rotary drill bit to move, the drill rod drives the connecting rod to move downward, the connecting rod drives the sleeve to move downward, the sleeve drives the support rod to move downward, and during the downward movement of the support rod, the diameter expander expands the diameter of the pile hole, and the support rod drives the casing to move downward, so that the rotary drill bit can rotary drill the pile hole, and at the same time, the first section of casing is installed. When the first section of casing is flush with the ground, the drill rod stops rotating, and the second section of casing is installed directly above the first section of casing, and then the drill rod is adjusted again so that the drill rod moves downward. The lifting assembly is used to lift the supporting rod downwards, and the lifting assembly is used to lift the supporting rod upwards, so that the supporting rod can be easily moved out along the inner cavity of the casing. Then the rotary drilling bit and the supporting rod are lifted above the ground. The drill residues generated during the rotary drilling of the pile hole are transported out of the pile hole along the lifting assembly, so that the soil in the pile hole is cleaned. The designed hole collapse prevention construction device realizes the support of the pile hole wall by the synchronous movement of the rotary drilling bit and the casing, so that the pile hole wall is in a protective state. At the same time, the synchronous action of the lifting assembly and the rotary drilling bit improves the efficiency of the rotary drilling of the pile hole, thereby improving the construction efficiency of the cast-in-place pile.

[0009] Optionally, a rotating cylinder is coaxially sleeved on the drill rod, a planetary gear is provided between the rotating cylinder and the drill rod, the rotating cylinder and the drill rod are rotationally connected via the planetary gear, and the connecting rod is connected to the outer wall of the sleeve.

[0010] By adopting the above technical solution, the rotation of the drill rod drives the planetary gear to rotate, the planetary gear drives the rotating drum to rotate, the rotating drum and the drill rod rotate in the opposite direction, the rotating drum drives the connecting rod to rotate, and the connecting rod drives the sleeve to rotate, thereby realizing the reverse rotation of the sleeve and the drill rod; the designed rotating drum and planetary gear make the rotating drum and the drill rod rotate in the opposite direction and create a speed difference between the rotating drum and the drill rod.

[0011] Optionally, the expansion member includes a connecting frame and a clamping roller, the connecting frame is fixedly connected to one end of the support rod away from the sleeve, the clamping roller is rotatably connected to the connecting frame, and the distance between the axis of the clamping roller and the axis of the drill rod is equal to the distance between the axis of the drill rod and the outer wall of the casing.

[0012] By adopting the above technical scheme, during the movement of the sleeve, the support rod is driven to rotate, the support rod drives the connecting frame to rotate, the connecting frame drives the clamping roller to move, the clamping roller abuts against the wall of the pile hole, and the friction between the clamping roller and the wall of the pile hole is used to realize the rotation of the clamping roller, and then the wall of the pile hole is pressed to realize the diameter expansion of the pile hole; the designed diameter expansion member improves the firmness of the wall of the pile hole through the pressure of the clamping roller on the wall of the pile hole, and at the same time, realizes the diameter expansion of the pile hole, which is convenient for the installation of the casing.

[0013] Optionally, the support rod is provided with an embedding groove for embedding the end of the casing at one end away from the sleeve.

[0014] By adopting the above technical solution, the designed embedding groove is convenient for limiting the end of the casing.

[0015] Optionally, a limiting block is arranged on the inner side wall of the collar, and a limiting groove for the limiting block to slide is opened on the outer side wall of the sleeve, and the limiting groove is arranged along the axial direction of the sleeve.

[0016] By adopting the above technical solution, the designed limit block and limit groove make it easy for the ring to move along the axial direction of the sleeve, so as to facilitate the lifting and lowering of the ring.

[0017] Optionally, a plurality of hooks are provided on the top wall of the ring.

[0018] By adopting the above technical solution, the designed hook makes it easy to apply force to the ring through external lifting equipment to achieve the rise or fall of the ring.

[0019] Optionally, the lifting assembly includes a spiral blade, the spiral blade is arranged concentrically with the drill pipe, and the spiral blade is located in the sleeve.

[0020] By adopting the above technical solution, when force is applied to the drill rod, the drill rod drives the spiral blades to rotate synchronously. At the same time, the drill rod drives the planetary gears to rotate, the planetary gears drive the rotating drum to rotate in the opposite direction, the rotating drum drives the connecting rod to rotate, and the connecting rod drives the sleeve to rotate in the opposite direction, thereby realizing the reverse rotation of the sleeve and the spiral blades, and then realizing the rapid lifting of drill cuttings; the designed lifting component is convenient for lifting the drill cuttings in the pile hole, so that the drill cuttings are lifted to the outside of the pile hole, thereby reducing the accumulation of drill cuttings in the pile hole.

[0021] Optionally, a support ring for abutting against an inner wall of the casing is provided on the outer periphery of the sleeve.

[0022] By adopting the above technical solution, the designed support ring is convenient for abutting against the inner wall of the casing to achieve support for the casing.

[0023] In a second aspect, the present application provides a cast-in-place pile construction process, comprising the following steps:

[0024] S1. Measure and lay out the positioning pile holes;

[0025] S2. Prefabrication of casing: the casing comprises a first arc segment and a second arc segment, the first arc segment and the second arc segment are symmetrically arranged about the axis of the casing, at least two positioning rods are arranged on the side of the first arc segment close to the second arc segment, and a positioning groove for inserting the positioning rods is opened on the side of the second arc segment close to the first arc segment;

[0026] S21, steel mesh preparation;

[0027] S22, steel mesh positioning;

[0028] S23, casting and forming of casing;

[0029] S3, rotary drilling;

[0030] S31, casing installation: the casing is sleeved on the sleeve, and the end of the sleeve is embedded in the limiting groove;

[0031] S32, rotary drilling of pile holes: the rotary drilling bit is driven by the drill rod to perform rotary drilling of the pile hole. During the drilling process of the rotary drilling bit, the spiral blade discharges the drill residue in the pile hole. At the same time, the sleeve drives the first section of the casing to move downward. When the first section of the casing moves to be flush with the ground, the second section of the casing is installed. After repeated installation, the installation of the casing is completed one by one during the rotary drilling of the pile hole.

[0032] S4, steel cage installation;

[0033] S5. Cast-in-place piles are cast into shape.

[0034] By adopting the above technical scheme, during the construction of cast-in-place piles, first, according to the construction requirements, the pile hole position is located by measuring and laying out; then, the casing is prefabricated, and after the casing is prefabricated; the end of the casing is embedded in the limit groove, and the inner wall of the casing is abutted against the support ring; then the drill rod is adjusted, and the drill rod drives the rotary drilling bit to perform rotary drilling of the pile hole, and at the same time, drives the first section of the casing to move downward. During the downward movement of the rotary drilling bit, the spiral blade lifts the soil sample in the pile hole to above the ground. When the first section of the casing is flush with the ground, the second section of the casing is installed, and the pile hole is continued to be rotary drilled, driving the first section of the casing to move downward. The first section casing and the second section casing move downward until the second section casing is away from one end of the first section casing and is flush with the ground, thereby realizing the successive installation of multiple sections of casing. After the casing is installed, the hole collapse prevention construction device is lifted above the ground, and then a steel cage is installed in the casing. After the steel cage is installed, concrete is poured into the inner cavity of the casing to realize the construction of bored piles. Through the bored pile construction process, it is convenient to prevent the hole collapse phenomenon during the pile hole opening process, improve the support performance of the pile hole wall during the rotary excavation process, and at the same time, improve the construction efficiency of the pile hole rotary excavation, thereby improving the construction efficiency of the bored piles.

[0035] In summary, the present application includes at least one of the following beneficial technical effects:

[0036] 1. The designed hole collapse prevention construction device realizes the support of the pile hole wall by the casing through the synchronous movement of the rotary drilling bit and the casing, so that the pile hole wall is in a protective state. At the same time, the synchronous action of the lifting component and the rotary drilling bit improves the efficiency of the pile hole rotary drilling, thereby improving the construction efficiency of the cast-in-place pile;

[0037] 2. The bored pile construction process can prevent the hole collapse during the pile hole opening process, improve the support performance of the pile hole wall during the rotary excavation process, and at the same time, improve the construction efficiency of the pile hole rotary excavation, thereby improving the construction efficiency of the bored pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the overall structure of the hole collapse prevention construction device of Example 1 of the present application;

[0039] Figure 2 is a cross-sectional view of a hole collapse prevention construction device according to Example 1 of the present application;

[0040] Figure 3 yes Figure 2 A magnified schematic diagram of part A;

[0041] Figure 4 yes Figure 2 An enlarged schematic diagram of part B;

[0042] Figure 5 yes Figure 2 An enlarged schematic diagram of the C portion;

[0043] Figure 6 It is a schematic diagram of the overall structure of the casing in Example 2 of the present application;

[0044] Figure 7 yes Figure 6 An enlarged schematic diagram of part D of FIG.

[0045] Explanation of the accompanying drawings: 1. drill rod; 2. rotary drill bit; 3. sleeve; 31. connecting rod; 32. rotating drum; 33. planetary gear; 331. driving gear; 332. driven gear; 333. gear ring; 34. support ring; 341. cavity; 4. support assembly; 41. expansion member; 411. connecting frame; 412. pressing roller; 42. support rod; 421. embedded groove; 43. pull rod; 44. collar; 45. limit block; 46. limit groove; 47. hook; 5. lifting assembly; 51. spiral blade; 6. casing; 61. limit ridge; 62. limit groove; 63. first arc segment; 64. second arc segment; 65. positioning rod; 66. positioning groove. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-7 This application is described in further detail.

[0047] The embodiments of the present application disclose a hole collapse prevention construction device and a cast-in-place pile construction process.

[0048] Example 1

[0049] Reference Figure 1 , Figure 2 and Figure 3 A hole collapse prevention construction device comprises a drill rod 1, a rotary drilling bit 2 for rotary drilling a pile hole, a sleeve 3, at least two groups of connecting rods 31, a lifting assembly 5 for taking soil, and a supporting assembly 4 for the casing 6 and the rotary drilling bit 2 to be synchronously lowered. The rotary drilling bit 2 is concentrically arranged with the drill rod 1, the rotary drilling bit 2 is fixedly connected to the suspended end of the drill rod 1, and the rotary drilling bit 2 is connected to the drill rod 1 through a bolt joint; one end of the connecting rod 31 is connected to the inner wall of the sleeve 3, and the other end is rotatably connected to the drill rod 1. The connecting rod 31 can be set as two groups, and can be set as It can be arranged into three groups or four groups, and the connecting rods 31 of each group can be arranged into three groups, can be arranged into four groups, or can be arranged into five groups, as long as the sleeve 3 and the drill pipe 1 are stably connected, in the present embodiment, two groups of connecting rods 31 are arranged, and the two groups of connecting rods 31 are arranged near the two ends of the sleeve 3 respectively, and each group of connecting rods 31 is arranged into three groups. In order to ensure that the connecting rods 31 are evenly stressed, the three connecting rods 31 are evenly distributed along the circumferential direction of the sleeve 3, and each connecting rod 31 is arranged along the radial direction of the drill pipe 1.

[0050] Reference Figure 3A rotary drum 32 is concentrically sleeved on the drill rod 1, a planetary gear 33 is arranged between the rotary drum 32 and the drill rod 1, and the planetary gear 33 is located in the inner cavity of the rotary drum 32, the rotary drum 32 and the drill rod 1 are rotatably connected through the planetary gear 33, the sleeve 3 is connected to three connecting rods 31, and the connecting rods 31 are welded to the rotary drum 32; the planetary gear 33 includes a driving gear 331, a gear ring 333 and three driven gears 332, the driving gear 331 is concentrically arranged with the drill rod 1, and the driving gear 331 is welded to the drill rod 1, and the three driven gears 33 2 are evenly distributed on the outer periphery of the driving gear 331, and the driving gear 331 is meshed with the driven gear 332, the driven gear 332 is rotatably connected with the rotating drum 32 through the rotating column, the gear ring 333 is concentrically arranged with the driving gear 331, and the gear ring 333 is sleeved on the outer periphery of the three driven gears 332, the gear ring 333 is meshed with the driven gear 332, the side of the gear ring 333 away from the driven gear 332 is integrally connected with the inner side wall of the rotating drum 32, and the gear ring 333 is concentrically arranged with the rotating drum 32, so as to realize the reverse rotation of the drill rod 1 and the rotating drum 32.

[0051] Reference Figure 4 and Figure 5The support assembly 4 includes a collar 44, a plurality of tie rods 43, a plurality of support rods 42 for supporting the casing 6, and an expander 41 for expanding the diameter of the pile hole. The support rods 42 can be set to three, four, or five to achieve stable support of the casing 6 by the support rods 42. In this embodiment, four support rods 42 are set. In order to extend the service life of the support rods 42 and ensure uniform force on the support rods 42, the four support rods 42 are evenly distributed along the circumferential direction of the sleeve 3. One end of the support rod 42 is rotatably connected to the sleeve 3, and the end of the support rod 42 away from the sleeve 3 is provided with an embedding groove 421 for embedding the end of the casing 6; the pull rod 43 is arranged one-to-one with the support rod 42, one end of the pull rod 43 is rotatably connected to the support rod 42, and the other end is rotatably connected to the collar 44; the collar 44 is concentrically arranged with the sleeve 3, and the collar 44 is slidably connected with the sleeve 3, a limit block 45 is arranged on the inner wall of the collar 44, and the limit block 45 is welded to the collar 44, and a limit block 45 is arranged on the outer wall of the sleeve 3 A limiting groove 46 for the limiting block 45 to slide is provided, and the limiting groove 46 is arranged along the axial direction of the sleeve 3; a plurality of hooks 47 are arranged on the top wall of the collar 44, and the hooks 47 can be arranged to be three, four, or five, as long as the lifting and lowering of the collar 44 by the external device is realized. In this embodiment, four hooks 47 are arranged. In order to ensure that the collar 44 is uniformly stressed during the lifting and lowering process, the four hooks 47 are evenly distributed along the circumferential direction of the collar 44, and the hooks 47 and the collar 4 4 welding; the rotary drilling bit 2 is located directly below the sleeve 3, and the horizontal projection diameter of the rotary drilling bit 2 is smaller than the inner diameter of the casing 6; in order to realize the support rod 42 of the casing 6, a support ring 34 for abutting the inner wall of the casing 6 is arranged on the outer periphery of the sleeve 3, the support ring 34 is concentrically arranged with the sleeve 3, and the support ring 34 is welded to the sleeve 3, the outer diameter of the support ring 34 is equal to the inner diameter of the casing 6, and in order to facilitate the external equipment to lift the sleeve 44, a cavity 341 for the external equipment to pass through is also opened on the support ring 34.

[0052] Reference Figure 3 and Figure 4 The expansion member 41 includes a connecting frame 411 and a clamping roller 412. The connecting frame 411 is located at the end of the support rod 42 away from the sleeve 3, and the connecting frame 411 is welded to the bottom wall of the support rod 42; the clamping roller 412 is rotatably connected to the connecting frame 411. In order to expand the diameter of the pile hole, the distance between the axis of the clamping roller 412 and the axis of the drill rod 1 is equal to the distance between the outer wall of the casing 6 and the axis of the drill rod 1.

[0053] Reference Figure 2 The lifting assembly 5 includes a spiral blade 51, which is concentrically arranged with the drill rod 1 and welded to the drill rod 1. The spiral blade 51 is located in the sleeve 3, and the spiral blade 51 is staggered with the connecting rod 31.

[0054] The implementation principle of the hole collapse prevention construction device of the first embodiment of the present application is as follows: when the pile hole is rotary excavated, first, force is applied to the collar 44, the collar 44 drives the pull rod 43 to move, the pull rod 43 drives the support rod 42 to move, and when the multiple support rods 42 are moved to the same plane, the first section of the casing 6 is installed on the support rod 42; then the drill rod 1 is adjusted, the drill rod 1 drives the rotary drilling drill bit 2 to move, the drill rod 1 drives the connecting rod 31 to move downward, the connecting rod 31 drives the sleeve 3 to move downward, the sleeve 3 drives the support rod 42 to move downward, and the support rod 42 drives the casing 6 to move downward, so as to realize the rotary excavation of the pile hole by the rotary drilling drill bit 2, and at the same time, The installation of the first section of casing 6 is realized; when the first section of casing 6 is flush with the ground, the drill rod 1 stops rotating, and the second section of casing 6 is installed directly above the first section of casing 6, and then the drill rod 1 is adjusted again to make the drill rod 1 move downward, thereby driving the second section of casing 6 to move downward, thereby realizing the successive installation of multiple sections of casing 6; after the installation of the casing 6 is completed, the driving ring 44 moves downward along the axial direction of the sleeve 3, the ring 44 drives the pull rod 43 to move, and the pull rod 43 pushes the support rod 42 to move downward, until the support rod 42 moves out along the inner cavity of the casing 6, and then the rotary drilling bit 2 and the support rod 42 are lifted to the outside of the pile hole.

[0055] During the rotation of the drill rod 1, the rotating rod drives the active gear 331 to rotate, the active gear 331 drives the driven gear 332 to rotate, the driven gear 332 drives the gear ring 333 to rotate, the gear ring 333 drives the rotating drum 32 to move, the rotating drum 32 drives the connecting rod 31 to rotate, the connecting rod 31 drives the sleeve 3 to rotate, so as to realize the reverse rotation of the sleeve 3 and the drill rod 1. At the same time, the drill rod 1 drives the spiral blade 51 to rotate, and the spiral blade 51 lifts the drill cuttings in the pile hole to the outside of the pile hole, thereby reducing the accumulation of drill cuttings in the pile hole.

[0056] Example 2

[0057] Reference Figure 6 and Figure 7 , a cast-in-place pile construction process, comprising the following steps:

[0058] S1. Measure and lay out the positioning pile holes: According to the construction requirements, measure and lay out the positions of the positioning pile holes and mark them;

[0059] S2, prefabrication of the casing 6: one end of the casing 6 is integrally connected to the limiting convex ridge 61, and the end of the casing 6 away from the limiting convex ridge 61 is provided with a limiting groove 62 for inserting the limiting convex ridge 61, and the casing 6 includes a first arc segment 63 and a second arc segment 64, and the first arc segment 63 and the second arc segment 64 are symmetrically arranged about the axis of the casing 6, and at least two positioning rods 65 are arranged on the side of the first arc segment 63 close to the second arc segment 64. In the present application, there are two positioning rods 65, and the positioning rods 65 are integrally cast with the first arc segment 63, and a positioning groove 66 for inserting the positioning rod 65 is arranged on the side of the second arc segment 64 close to the first arc segment 63;

[0060] S21, preparing a steel mesh: preparing a steel mesh according to the shapes of the first arc segment 63 and the second arc segment 64;

[0061] S22, steel mesh positioning: placing the steel mesh in the forming mold and limiting the position by positioning pins;

[0062] S23, casting and forming the casing 6: first, pouring concrete, and then spraying and curing, until the formed first arc segment 63 and second arc segment 64 meet the construction requirements;

[0063] S3, rotary drilling;

[0064] S31, installation of the first section of the casing 6: insert one end of the casing 6 with the limiting groove 62 into the limiting groove 46, and then install the casing 6 on the outer periphery of the sleeve 3. During the installation of the first arc segment 63 and the second arc segment 64, the positioning rod 65 is completely inserted into the positioning groove 66;

[0065] S32, rotary drilling of pile holes: the rotary drilling bit 2 is driven by the drill rod 1 to perform rotary drilling of pile holes. During the rotary drilling of the rotary drilling bit 2, the spiral blade 51 lifts the drill residue in the pile hole to above the ground. At the same time, the sleeve 3 drives the first section casing 6 to move downward. When the first section casing 6 is flush with the ground, the second section casing 6 is installed. During the installation of the second section casing 6, the limiting ridge 61 of the first section casing 6 is completely inserted into the limiting groove 62 of the second section casing 6, and the connecting seams of the first arc segment 63 and the second arc segment 64 of the two adjacent sections of casing 6 are staggered. Then, the drill rod 1 is adjusted again to make the drill rod 1 move downward, thereby driving the second section casing 6 to move downward, so as to realize the successive installation of multiple sections of casing 6 until the installation of multiple sections of casing 6 is completed.

[0066] S4, steel cage installation: according to the construction requirements, install the steel cage into the inner cavity of the casing 6;

[0067] S5. Casting of bored piles: After the steel cage is installed, concrete is poured into the inner cavity of the casing 6. After a period of spraying and curing, the bored piles meet the construction requirements.

[0068] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction device for preventing hole collapse, comprising a drill rod (1) and a rotary drilling drill bit (2) for rotary drilling of pile holes, wherein the rotary drilling drill bit (2) is arranged concentrically with the drill rod (1), and the rotary drilling drill bit (2) is fixedly connected to the suspended end of the drill rod (1), characterized in that: The drill bit (2) further comprises a sleeve (3), at least two groups of connecting rods (31), a lifting assembly (5) for lifting drill cuttings, and a supporting assembly (4) for synchronously lowering the casing (6) and the rotary drill bit (2); the sleeve (3) is arranged concentrically with the drill rod (1); one end of the connecting rod (31) is connected to the inner wall of the sleeve (3), and the other end is rotatably connected to the drill rod (1); the supporting assembly (4) comprises a collar (44), a plurality of pull rods (43), a lifting assembly (5) for supporting the casing (6), and a supporting assembly (4) for synchronously lowering the casing (6) and the rotary drill bit (2). A plurality of support rods (42) and a diameter expander (41) for expanding the diameter of a pile hole, wherein one end of the support rod (42) is rotatably connected to a sleeve (3), one end of a pull rod (43) is rotatably connected to the support rod (42), and the other end is rotatably connected to the collar (44), the collar (44) is slidably connected to the sleeve (3), the rotary drill bit (2) is located directly below the sleeve (3), and the horizontal projection diameter of the rotary drill bit (2) is smaller than the inner diameter of the casing (6).

2. The hole collapse prevention construction device according to claim 1, characterized in that: A rotating cylinder (32) is coaxially sleeved on the drill rod (1), a planetary gear (33) is arranged between the rotating cylinder (32) and the drill rod (1), the rotating cylinder (32) and the drill rod (1) are rotationally connected via the planetary gear (33), and the connecting rod (31) is connected to the outer wall of the sleeve (3).

3. The hole collapse prevention construction device according to claim 1, characterized in that: The diameter expansion member (41) comprises a connecting frame (411) and a pressing roller (412); the connecting frame (411) is fixedly connected to one end of the support rod (42) away from the sleeve (3); the pressing roller (412) is rotatably connected to the connecting frame (411); and the distance between the axis of the pressing roller (412) and the axis of the drill rod (1) is equal to the distance between the axis of the drill rod (1) and the outer wall of the casing (6).

4. The hole collapse prevention construction device according to claim 3 is characterized in that: An embedding groove (421) for embedding the end of the protective tube (6) is formed at one end of the support rod (42) away from the sleeve (3).

5. The hole collapse prevention construction device according to claim 3, characterized in that: A limiting block (45) is arranged on the inner wall of the collar (44), and a limiting groove (46) for the limiting block (45) to slide is opened on the outer wall of the sleeve (3), and the limiting groove (46) is arranged along the axial direction of the sleeve (3).

6. The hole collapse prevention construction device according to claim 3, characterized in that: A plurality of hooks (47) are arranged on the top wall of the collar (44).

7. The hole collapse prevention construction device according to claim 5, characterized in that: The lifting assembly (5) comprises a spiral blade (51), the spiral blade (51) is arranged concentrically with the drill rod (1), and the spiral blade (51) is located inside the sleeve (3).

8. The hole collapse prevention construction device according to claim 1, characterized in that: A support ring (34) is provided on the outer periphery of the sleeve (3) for abutting against the inner wall of the casing (6).

9. A cast-in-place pile construction process, characterized in that: The following steps are involved: S1. Measure and lay out the positioning pile holes; S2. Prefabrication of the casing (6): the casing (6) comprises a first arc segment (63) and a second arc segment (64), the first arc segment (63) and the second arc segment (64) are symmetrically arranged about the axis of the casing (6), at least two positioning rods (65) are arranged on a side of the first arc segment (63) close to the second arc segment (64), and a positioning groove (66) for inserting the positioning rod (65) is opened on a side of the second arc segment (64) close to the first arc segment (63); S21, steel mesh preparation; S22, steel mesh positioning; S23, casting the casing (6); S3, rotary drilling: using the hole collapse prevention construction device according to claim 7; S31, installing the protective tube (6): sleeve the protective tube (6) onto the sleeve (3), and embed the end of the sleeve (3) into the limiting groove (46); S32, rotary drilling of the pile hole: the rotary drilling bit (2) is driven by the drill rod (1) to perform rotary drilling of the pile hole. During the drilling process of the rotary drilling bit (2), the spiral blade (51) discharges the drilling debris in the pile hole out of the pile hole. At the same time, the sleeve (3) drives the first section of the casing (6) to move downward. When the first section of the casing (6) is flush with the ground, the second section of the casing (6) is installed. After repeated installation, the installation of the casing (6) is completed one by one during the rotary drilling of the pile hole. S4, steel cage installation; S5. Cast-in-place piles are cast into shape.

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