Steel casing construction device and construction method for bored cast-in-place pile

Abstract

The present invention relates to the field of bored cast-in-place pile construction. The present invention discloses a construction device and a construction method for a steel casing of a bored cast-in-place pile. The problem to be solved by the present invention is that by pressing down the top of the steel casing with a pile driver, the entire steel casing is inserted into the soil at one time, and it is difficult to ensure the verticality of the steel casing inserted into the soil. The present invention consists of a tubular locking and pressing mechanism and a supporting and limiting mechanism. The construction device and the construction method for the steel casing of the bored cast-in-place pile extend one end of a hydraulic cylinder into the steel casing through a pile driver. By the elongation of the hydraulic cylinder, the three-fold plate on it abuts against the convex block and deflects, so that the vertical plate on the three-fold plate abuts against the inner wall of the steel casing. Then, the pile driver drives the steel casing to move to a designated position and inserts its lower end into a designated area to realize the pre-fixation of the steel casing, which is convenient for detecting the verticality of the pre-fixed steel casing and ensuring the verticality of the steel casing inserted into the soil by the subsequent device.

Description

Technical Field

[0001] The present invention relates to the field of bored cast-in-place pile construction, and specifically to a construction device and construction method for steel casing of bored cast-in-place piles. Background Technique

[0002] A bored cast-in-place pile refers to a pile formed by means of mechanical drilling, steel pipe soil extrusion or manual excavation at the construction site in the foundation soil, and placing a steel reinforcement cage and pouring concrete therein. When constructing bridge pile foundations, it is necessary to excavate the pile holes. To prevent the collapse of the holes and avoid affecting the construction progress and safety accidents, steel casings are often used to protect the pile holes.

[0003] When the existing construction device for steel casing of bored cast-in-place piles inserts the steel casing into the soil, most of them press down the top of the steel casing through a pile driver, and then insert the entire steel casing into the soil at one time. It is difficult to ensure the verticality of the steel casing inserted into the soil. However, due to the certain length of the steel casing itself, when the pile driver inserts the steel casing into the soil at one time, the overall stress on the steel casing is too large, resulting in deformation of the steel casing when it is inserted into the soil, affecting the quality of the subsequent use of the steel casing. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction device and construction method for steel casing of bored cast-in-place piles to solve the problem proposed in the above background technique that by pressing down the top of the steel casing through a pile driver and then inserting the entire steel casing into the soil at one time, it is difficult to ensure the verticality of the steel casing inserted into the soil. However, due to the certain length of the steel casing itself, when the pile driver inserts the steel casing into the soil at one time, the overall stress on the steel casing is too large, resulting in deformation of the steel casing when it is inserted into the soil, affecting the quality of the subsequent use of the steel casing. To achieve the above purpose, the present invention provides the following technical solution: A construction device for steel casing of bored cast-in-place piles, including a fixed rod, a pressure plate is installed at the lower end of the fixed rod, a support frame is installed directly below the pressure plate, and a tubular locking and pressing-down mechanism is fixedly connected to the lower end of the support frame. The steel casing is locked and pushed downward during the pressing-down process of the tubular locking and pressing-down mechanism to drive the steel casing into the soil;

[0005] A resistance plate is arranged at the lower end of the tubular locking and pressing-down mechanism, and a support and limiting mechanism is arranged on the outside of the resistance plate and is installed on the support frame.

[0006] Preferably, the tubular locking and pressing-down mechanism includes a hydraulic cylinder fixed directly below the support frame, a limit sleeve is installed on the hydraulic cylinder, and a convex block is fixedly connected to the through groove on the surface of the limit sleeve;

[0007] Four three-fold plates are hinged to the inner rod of the hydraulic cylinder, and the four three-fold plates are evenly distributed in a ring shape. The three-fold plates are slidably arranged in the through groove of the limit sleeve.

[0008] Preferably, the tubular locking and pressing mechanism further includes a spring telescopic tube fixed to the end of the support frame. Sixteen parallel rods are hinged on the inner wall of the inner tube of the spring telescopic tube. The sixteen parallel rods are divided into four groups, and the four parallel rods in each group are arranged in a rectangular distribution. First spring telescopic rods are hinged between the eight parallel rods on the lower side and the inner tube of the spring telescopic tube;

[0009] One end of the four parallel rods in each group away from the inner tube of the spring telescopic tube is hinged with an arc-shaped clamping plate. A one-way bearing is installed on the arc-shaped clamping plate. The lower end of the arc-shaped clamping plate is fixedly connected with a pressing block, and the pressing block abuts against the lower end of the inner tube of the spring telescopic tube and the resistance disc.

[0010] Preferably, the support and limit mechanism includes arc-shaped telescopic plates fixed to both ends of the support frame. A chute is opened on the outer tube of the arc-shaped telescopic plate. A sliding plate is slidably connected in the chute. Two first inclined surfaces are opened at one end of the sliding plate located inside the arc-shaped telescopic plate. A damping spring telescopic rod is fixedly connected between the sliding plate and the bottom plate of the arc-shaped telescopic plate;

[0011] An L-shaped clamping block is inserted through the outer tube of the arc-shaped telescopic plate. One end of the L-shaped clamping block extends into the chute and is inserted into a wedge-shaped groove opened on the sliding plate. The lower end of the L-shaped clamping block is fixedly connected with a second spring telescopic rod, and the end of the second spring telescopic rod away from the L-shaped clamping block is fixed on the arc-shaped telescopic plate.

[0012] Preferably, a groove is opened at the bottom end of the resistance disc. The inner wall of the groove fits with one end of the sliding plate. A wedge-shaped block is inserted through the resistance disc. The inclined surface at the end of the wedge-shaped block abuts against the first inclined surface. A reset spring telescopic rod is installed on the wedge-shaped block. One end of the reset spring telescopic rod is fixed on the resistance disc. The side surface of the wedge-shaped block is fixedly connected with a third spring telescopic rod. Two cut surfaces are opened at the end of the third spring telescopic rod away from the wedge-shaped block, and the end of the third spring telescopic rod with an inclined surface is lapped on the inner side of the L-shaped clamping block.

[0013] Preferably, the three-fold plate is formed by hinging two parallel plates and a vertical plate.

[0014] Preferably, an anti-slip ring is provided on the outer ring of the one-way bearing.

[0015] Preferably, the construction method of the steel casing construction device for bored cast-in-place piles includes the following steps:

[0016] S1: Connect the upper end of the fixed rod to the head of the pile driver. Then, extend one end of the hydraulic cylinder into the steel casing through the pile driver. When the hydraulic cylinder extends, the three-fold plate on it will contact the convex block and deflect, causing the vertical plate on the three-fold plate to contact the inner wall of the steel casing. Then, drive the steel casing to move to the designated position through the pile driver and insert its lower end into the designated area.

[0017] Then, when the hydraulic cylinder contracts, drive the vertical plate of the three-fold plate to separate from the inner wall of the steel casing. At this time, drive the pressure plate and the support frame to move downward through the pile driver, so that the spring telescopic tube contracts and cooperates with the parallel rod to drive the pressing block to contact the upper side of the resistance plate. At this time, the parallel rod deflects and drives the four arc-shaped clamping plates to move towards the central axis of the spring telescopic tube, and then contact the outer side of the steel casing and fix it. Then, continue to push the spring telescopic tube downward through the pile driver. At this time, the spring telescopic tube has contracted to the shortest value, and the lower end of the spring telescopic tube pushes the resistance plate downward, causing the first inclined surface provided on the sliding plate inside the resistance plate to squeeze the wedge block to move. The wedge block cooperates with the third spring telescopic rod to move and drive the L-shaped clamping block stuck on the sliding plate to move and separate from it, unlocking the locking state of the L-shaped clamping block on the sliding plate.

[0018] S2: At this time, the resistance plate continues to move downward under the thrust of the pile driver, so that the tangent surface on the lower side of the end of the third spring telescopic rod contacts the inner side of the L-shaped clamping block, pushing the third spring telescopic rod to contract to ensure the stable downward movement of the resistance plate. At this time, the steel casing continues to penetrate into the soil under the action of the clamping force of the four arc-shaped clamping plates and the one-way bearing inside it. When the resistance plate moves downward, it pushes the damping spring telescopic rod to compress. When the damping spring telescopic rod contracts to the shortest value, the pile driver starts to drive the fixed rod to move upward. At this time, the outer ring of the one-way bearing rolls on the outer side of the steel casing, reducing the friction between the one-way bearing and the outer wall of the steel casing.

[0019] S3: And when the pile driver drives the fixed rod to move upward, the damping spring telescopic rod has a damping force when it extends, thereby ensuring that when the pile driver drives the fixed rod to move upward, the lower end of the resistance plate separates from the sliding plate. At this time, the resistance plate separates from the bottom surface of the pressing block under the action of the restoring force of the spring telescopic tube. And at this time, the parallel rod drives the pressing block to separate from the outer wall of the steel casing under the action of the pulling force of the first spring telescopic rod, that is, unlocks the locking state of the arc-shaped clamping plate on the steel casing. And during the upward movement of the resistance plate, the tangent surface on the upper side of the end of the third spring telescopic rod contacts the lower side of the L-shaped clamping block. After assisting in pulling the damping spring telescopic rod to reset, the L-shaped clamping block cannot continue to move upward. At this time, the tangent surface on the lower side of the third spring telescopic rod contacts the lower side of the L-shaped clamping block and is forced to contract, and moves to the upper side of the L-shaped clamping block, that is, completes the reset of the device. Then, drive the fixed rod to move downward again through the pile driver to realize the penetration of the steel casing into the soil. Repeat this process to insert the steel casing into the designated soil.

[0020] Compared with the prior art, the beneficial effects of the present invention:

[0021] In the present invention, one end of a hydraulic cylinder is inserted into a steel casing through a pile driver. As the hydraulic cylinder extends, the three-fold plate thereon abuts against a convex block and deflects, causing the vertical plate on the three-fold plate to abut against the inner wall of the steel casing. Then, the pile driver drives the steel casing to move to a designated position and inserts its lower end into a designated area, achieving pre-fixation of the steel casing, facilitating the detection of the verticality of the pre-fixed steel casing, and ensuring the verticality of the steel casing inserted into the soil by the subsequent device.

[0022] In the present invention, the pile driver drives a pressure plate and a support frame to move downward, causing the parallel rod to deflect and driving four arc-shaped clamping plates to move towards the central axis of the spring telescopic tube, thereby abutting against the outside of the steel casing and fixing it. Then, the pile driver moves downward to continue inserting the steel casing into the soil. Then, the pile driver moves upward to unlock the clamping of the four arc-shaped clamping plates on the steel casing. The pile driver reciprocates and intermittently drives the steel casing into the soil, preventing the device from completely inserting the steel casing into the soil at once, which may cause excessive stress on the steel casing and deformation, affecting the subsequent use of the steel casing.

[0023] In the present invention, when the pile driver moves downward to continue inserting the steel casing into the soil, since the four arc-shaped clamping plates are clamped around the middle part of the outside of the steel casing, the stress on the overall steel casing during the insertion of the steel casing into the soil by the pile driver is reduced, and the practicability is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a three-dimensional structure schematic diagram of the present invention;

[0025] Figure 2 is a partial three-dimensional structure schematic diagram of the present invention;

[0026] Figure 3 is a partial three-dimensional structure sectional view of the present invention;

[0027] Figure 4 is a partial three-dimensional unfolded structure sectional view of the present invention;

[0028] Figure 5 is one of the three-dimensional unfolded structure schematic diagrams of the resistance plate of the present invention;

[0029] Figure 6 is the second three-dimensional unfolded structure schematic diagram of the resistance plate of the present invention;

[0030] Figure 7 is a three-dimensional structure sectional view of the arc-shaped telescopic plate of the present invention.

[0031] In the figure: 1. Fixed rod; 2. Pressure plate; 3. Support frame; 4. Tubular locking and pressing mechanism; 41. Hydraulic cylinder; 42. Limiting sleeve; 43. Convex block; 44. Three-fold plate; 45. Spring telescopic tube; 46. Parallel rod; 47. Arc-shaped clamping plate; 48. One-way bearing; 49. Pressing block; 410. First spring telescopic rod; 5. Resistance disk; 51. Groove; 52. Wedge block; 53. Reset spring telescopic rod; 54. Third spring telescopic rod; 6. Support and limit mechanism; 61. Arc-shaped telescopic plate; 62. Chute; 63. Slide plate; 64. Damping spring telescopic rod; 65. L-shaped clamping block; 66. Second spring telescopic rod; 67. First inclined plane. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical staff in the art without creative work fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 7 , the present invention provides a technical solution: a construction device for a steel casing of a bored cast-in-place pile, including a fixed rod 1, a pressure plate 2 is installed at the lower end of the fixed rod 1, a support frame 3 is installed directly below the pressure plate 2, and a tubular locking and pressing mechanism 4 is fixedly connected to the lower end of the support frame 3. During the downward pressing process of the tubular locking and pressing mechanism 4, the steel casing is locked and pushed downward to drive the steel casing into the soil;

[0034] A resistance disk 5 is provided at the lower end of the tubular locking and pressing mechanism 4, a support and limit mechanism 6 is provided on the outer side of the resistance disk 5, and the support and limit mechanism 6 is installed on the support frame 3.

[0035] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown, the tubular locking and pressing mechanism 4 includes a hydraulic cylinder 41 fixed directly below the support frame 3, a limiting sleeve 42 is installed on the hydraulic cylinder 41, and a convex block 43 is fixedly connected in a through groove on the surface of the limiting sleeve 42;

[0036] Four three-fold plates 44 are hinged on the inner rod of the hydraulic cylinder 41, and the four three-fold plates 44 are evenly distributed in a ring shape at equal distances, and the three-fold plates 44 are slidably arranged in the through groove of the limiting sleeve 42.

[0037] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, the tubular locking and pressing mechanism 4 further includes a spring telescopic tube 45 fixed to the end of the support frame 3. Sixteen parallel bars 46 are hinged to the inner wall of the inner tube of the spring telescopic tube 45. And the sixteen parallel bars 46 are grouped into four as a group, and the four parallel bars 46 in each group are arranged in a rectangular distribution. A first spring telescopic rod 410 is hinged between the eight lower parallel bars 46 and the inner tube of the spring telescopic tube 45;

[0038] One end of the four parallel bars 46 in each group away from the inner tube of the spring telescopic tube 45 is hinged with an arc-shaped clamping plate 47. A one-way bearing 48 is installed on the arc-shaped clamping plate 47. The lower end of the arc-shaped clamping plate 47 is fixedly connected with a pressing block 49, and the pressing block 49 abuts against the lower end of the inner tube of the spring telescopic tube 45 and against the resistance disk 5.

[0039] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, the support and limit mechanism 6 includes arc-shaped telescopic plates 61 fixed to both ends of the support frame 3. A chute 62 is opened on the outer tube of the arc-shaped telescopic plate 61. A sliding plate 63 is slidably connected in the chute 62. And two first inclined surfaces 67 are opened at one end of the sliding plate 63 located inside the arc-shaped telescopic plate 61. A damping spring telescopic rod 64 is fixedly connected between the sliding plate 63 and the bottom plate of the arc-shaped telescopic plate 61;

[0040] An L-shaped clamping block 65 is inserted through the outer tube of the arc-shaped telescopic plate 61. One end of the L-shaped clamping block 65 extends into the chute 62 and is inserted into a wedge-shaped groove opened on the sliding plate 63. The lower end of the L-shaped clamping block 65 is fixedly connected with a second spring telescopic rod 66. The end of the second spring telescopic rod 66 away from the L-shaped clamping block 65 is fixed on the arc-shaped telescopic plate 61. One end of the L-shaped clamping block 65 close to the sliding plate 63 is an inclined surface.

[0041] In this embodiment, as Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, a groove 51 is opened at the bottom end of the resistance disk 5. The inner wall of the groove 51 is attached to one end of the sliding plate 63. A wedge-shaped block 52 is inserted through the resistance disk 5. The inclined surface at the end of the wedge-shaped block 52 abuts against the first inclined surface 67. A reset spring telescopic rod 53 is installed on the wedge-shaped block 52. One end of the reset spring telescopic rod 53 is fixed on the resistance disk 5. The side of the wedge-shaped block 52 is fixedly connected with a third spring telescopic rod 54. Two cut surfaces are opened at the end of the third spring telescopic rod 54 away from the wedge-shaped block 52. And the end of the third spring telescopic rod 54 with an inclined surface is lapped on the inner side of the L-shaped clamping block 65.

[0042] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown, the triple-fold plate 44 is formed by hinging two parallel plates and a vertical plate.

[0043] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown, an anti-slip ring is provided on the outer ring of the one-way bearing 48.

[0044] Construction method and advantages of the present invention: The construction method of the construction device for the steel casing of bored cast-in-place piles is as follows:

[0045] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 shown:

[0046] S1: Connect the upper end of the fixed rod 1 to the head of the pile driver, and then extend one end of the hydraulic cylinder 41 into the steel casing through the pile driver. Drive the triple-fold plate 44 on it to contact the convex block 43 and deflect by the elongation of the hydraulic cylinder 41, so that the vertical plate on the triple-fold plate 44 contacts the inner wall of the steel casing. Then drive the steel casing to move to the designated position by the pile driver and insert its lower end into the designated area;

[0047] Then drive the vertical plate of the triple-fold plate 44 to separate from the inner wall of the steel casing by the contraction of the hydraulic cylinder 41. At this time, drive the pressure plate 2 and the support frame 3 to move downward by the pile driver, so that the spring telescopic tube 45 contracts and cooperates with the parallel rod 46 to drive the pressing block 49 to contact the upper side of the resistance plate 5. At this time, the parallel rod 46 deflects to drive the four arc-shaped clamping plates 47 to move towards the central axis of the spring telescopic tube 45, and then contact the outer side of the steel casing and fix it. Then continue to push the spring telescopic tube 45 downward by the pile driver. At this time, the spring telescopic tube 45 has contracted to the shortest value, and the lower end of the spring telescopic tube 45 pushes the resistance plate 5 downward, so that the first inclined surface 67 provided on the sliding plate 63 inside the resistance plate 5 squeezes the wedge-shaped block 52 to move. The wedge-shaped block 52 and the third spring telescopic rod 54 cooperate to move and drive the L-shaped clamping block 65 stuck on the sliding plate 63 to move and separate from it, unlocking the locking state of the L-shaped clamping block 65 on the sliding plate 63;

[0048] S2: At this time, the resistance plate 5 continues to move downward under the thrust of the pile driver, causing the lower side of the end of the third spring telescopic rod 54 to contact the inner side of the L-shaped block 65, pushing the third spring telescopic rod 54 to contract, ensuring the stable downward movement of the resistance plate 5. At this time, the steel casing continues to penetrate into the soil under the clamping force of the four arc-shaped clamping plates 47 and the one-way bearing 48 inside it. When the resistance plate 5 moves downward, it pushes the damping spring telescopic rod 64 to compress. When the damping spring telescopic rod 64 contracts to the shortest value, the pile driver starts to drive the fixed rod 1 to move upward. At this time, the outer ring of the one-way bearing 48 rolls on the outer side of the steel casing, reducing the friction between the one-way bearing 48 and the outer wall of the steel casing;

[0049] S3: And when the pile driver drives the fixed rod 1 to move upward, the damping spring telescopic rod 64 has a damping force during elongation. Thus, when the pile driver drives the fixed rod 1 to move upward, the lower end of the resistance plate 5 separates from the slide plate 63. At this time, the resistance plate 5 separates from the bottom surface of the pressing block 49 under the restoring force of the spring telescopic tube 45. And at this time, the parallel rod 46 drives the pressing block 49 to separate from the outer wall of the steel casing under the pulling force of the first spring telescopic rod 410, that is, unlocks the locking state of the arc-shaped clamping plate 47 on the steel casing. And during the upward movement of the resistance plate 5, the upper side of the end of the third spring telescopic rod 54 contacts the lower side of the L-shaped block 65. After the auxiliary pulling to complete the reset of the damping spring telescopic rod 64, the L-shaped block 65 cannot continue to move upward. At this time, the lower side of the third spring telescopic rod 54 contacts the lower side of the L-shaped block 65 and is forced to contract, and moves to the upper side of the L-shaped block 65, that is, completes the reset of the device. Then, the pile driver drives the fixed rod 1 to move downward again, realizing the penetration of the steel casing into the soil. Repeat this process to insert the steel casing into the specified soil.

[0050] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only the preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A construction device for steel casing of bored cast-in-place pile, including a fixed rod (1), characterized in that: A pressure plate (2) is installed at the lower end of the fixed rod (1). A support frame (3) is installed directly below the pressure plate (2). The lower end of the support frame (3) is fixedly connected to a tubular locking and pressing mechanism (4). During the downward pressing process of the tubular locking and pressing mechanism (4), the steel casing is locked and pushed downward to drive the steel casing into the soil. A resistance plate (5) is arranged at the lower end of the tubular locking and pressing mechanism (4). A support and limiting mechanism (6) is arranged on the outer side of the resistance plate (5), and the support and limiting mechanism (6) is installed on the support frame (3). The tubular locking and pressing mechanism (4) includes a hydraulic cylinder (41) fixed directly below the support frame (3). A limit sleeve (42) is installed on the hydraulic cylinder (41). A convex block (43) is fixedly connected in a through groove on the surface of the limit sleeve (42). Four three-fold plates (44) are hinged on the inner rod of the hydraulic cylinder (41), and the four three-fold plates (44) are evenly distributed in a ring at equal distances. The three-fold plates (44) are slidably arranged in the through groove of the limit sleeve (42). The tubular locking and pressing mechanism (4) further includes a spring telescopic tube (45) fixed at the end of the support frame (3). Sixteen parallel rods (46) are hinged on the inner wall of the inner tube of the spring telescopic tube (45). The sixteen parallel rods (46) are divided into four groups, and the four parallel rods (46) in each group are arranged in a rectangle. A first spring telescopic rod (410) is hinged between the eight parallel rods (46) on the lower side and the inner tube of the spring telescopic tube (45). One end of the four parallel rods (46) in each group, which is far away from the inner tube of the spring telescopic tube (45), is hinged to an arc-shaped clamping plate (47). A one-way bearing (48) is installed on the arc-shaped clamping plate (47). A pressing block (49) is fixedly connected to the lower end of the arc-shaped clamping plate (47). The pressing block (49) abuts against the lower end of the inner tube of the spring telescopic tube (45) and the resistance plate (5). The support and limiting mechanism (6) includes arc-shaped telescopic plates (61) fixed at both ends of the support frame (3). A chute (62) is opened on the outer tube of the arc-shaped telescopic plate (61). A sliding plate (63) is slidably connected in the chute (62). Two first inclined surfaces (67) are opened at one end of the sliding plate (63) located inside the arc-shaped telescopic plate (61). A damping spring telescopic rod (64) is fixedly connected between the sliding plate (63) and the bottom plate of the arc-shaped telescopic plate (61). An L-shaped clamping block (65) is inserted through the outer tube of the arc-shaped telescopic plate (61). One end of the L-shaped clamping block (65) extends into the chute (62) and is inserted into a wedge-shaped groove opened on the sliding plate (63). A second spring telescopic rod (66) is fixedly connected to the lower end of the L-shaped clamping block (65). The end of the second spring telescopic rod (66) far away from the L-shaped clamping block (65) is fixed on the arc-shaped telescopic plate (61). A groove (51) is formed at the bottom end of the resistance disc (5). The inner wall of the groove (51) is in contact with one end of the sliding plate (63). A wedge block (52) is inserted through the resistance disc (5). The inclined surface at the end of the wedge block (52) abuts against the first inclined surface (67). A return spring telescopic rod (53) is installed on the wedge block (52). One end of the return spring telescopic rod (53) is fixed on the resistance disc (5). A third spring telescopic rod (54) is fixedly connected to the side surface of the wedge block (52). Two cut surfaces are formed at the end of the third spring telescopic rod (54) away from the wedge block (52), and the end of the third spring telescopic rod (54) with an inclined surface is lapped on the inner side of the L-shaped clamping block (65).

2. The steel casing construction device for bored cast-in-place piles according to claim 1, characterized in that: The three-fold plate (44) is formed by hinging two parallel plates and a vertical plate together.

3. The construction device for steel casing of bored cast-in-place pile according to claim 1, characterized in that: An anti-slip ring is provided on the outer ring of the one-way bearing (48).

4. The construction method of the steel casing construction device for bored cast-in-place piles according to claim 1, characterized in that: It includes the following steps: S1: Connect the upper end of the fixed rod (1) to the head of the pile driver. Then, through the pile driver, one end of the hydraulic cylinder (41) is inserted into the steel casing. By extending the hydraulic cylinder (41), the three-fold plate (44) thereon abuts against the convex block (43) and deflects, so that the vertical plate on the three-fold plate (44) abuts against the inner wall of the steel casing. Then, drive the steel casing to move to the designated position through the pile driver and insert its lower end into the designated area. Then, by contracting the hydraulic cylinder (41), the vertical plate of the three-fold plate (44) is separated from the inner wall of the steel casing. At this time, drive the pressure plate (2) and the support frame (3) to move downward through the pile driver, so that the spring telescopic tube (45) contracts to cooperate with the parallel rod (46) to drive the pressing block (49) to abut against the upper side of the resistance disc (5). At this time, the parallel rod (46) deflects to drive the four arc-shaped clamping plates (47) to move towards the central axis of the spring telescopic tube (45), and then abut against the outer side of the steel casing and fix it. Then, continue to push the spring telescopic tube (45) downward through the pile driver. At this time, the spring telescopic tube (45) has contracted to the shortest value, and the lower end of the spring telescopic tube (45) pushes the resistance disc (5) downward, so that the first inclined surface (67) provided on the sliding plate (63) inside the resistance disc (5) squeezes the wedge block (52) to move. The cooperation movement of the wedge block (52) and the third spring telescopic rod (54) drives the L-shaped clamping block (65) stuck on the sliding plate (63) to move and separate from it, unlocking the locked state of the L-shaped clamping block (65) on the sliding plate (63). S2: At this time, the resistance plate (5) continues to move downward under the thrust of the pile driver, causing the lower side of the end of the third spring telescopic rod (54) to contact the inner side of the L-shaped block (65), pushing the third spring telescopic rod (54) to contract and ensuring the stable downward movement of the resistance plate (5). At this time, the steel casing continues to penetrate into the soil under the clamping force of the four arc-shaped clamping plates (47) and the one-way bearing (48) inside it. When the resistance plate (5) moves downward, it pushes the damping spring telescopic rod (64) to compress. When the damping spring telescopic rod (64) contracts to the shortest value, the pile driver starts to drive the fixed rod (1) to move upward. At this time, the outer ring of the one-way bearing (48) rolls on the outside of the steel casing, reducing the friction between the one-way bearing (48) and the outer wall of the steel casing; S3: And when the pile driver drives the fixed rod (1) to move upward, the damping spring telescopic rod (64) has a damping force during elongation, thereby ensuring that when the pile driver drives the fixed rod (1) to move upward, the lower end of the resistance plate (5) separates from the sliding plate (63). At this time, the resistance plate (5) separates from the bottom surface of the pressing block (49) under the action of the restoring force of the spring telescopic tube (45). And at this time, the parallel rod (46) drives the pressing block (49) to separate from the outer wall of the steel casing under the action of the pulling force of the first spring telescopic rod (410), that is, unlocks the locking state of the arc-shaped clamping plate (47) on the steel casing. And during the upward movement of the resistance plate (5), the upper side of the end of the third spring telescopic rod (54) contacts the lower side of the L-shaped block (65). After assisting in pulling the damping spring telescopic rod (64) to reset, the L-shaped block (65) cannot continue to move upward. At this time, the lower side of the third spring telescopic rod (54) contacts the lower side of the L-shaped block (65) and is forced to contract, and moves to the upper side of the L-shaped block (65), that is, completes the reset of the device. Then, the pile driver drives the fixed rod (1) to move downward again to realize the penetration of the steel casing into the soil. Repeat this process to insert the steel casing into the specified soil.

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