Bottom expansion device and construction method for punching and bottom expansion cast-in-place pile

Abstract

The present application relates to a bottom expansion device and construction method for a punched, bottom-expanded cast-in-place pile, belonging to the field of punched, bottom-expanded cast-in-place pile construction technology. The device comprises a pile expansion head connected to the end of a drill pipe, the pile expansion head comprising a fixed shaft and a sleeve sleeved on the fixed shaft, the fixed shaft being connected to the drill pipe, and two bottom expansion wings being connected to both sides of the fixed shaft and the sleeve. The bottom expansion wings fold toward the fixed shaft and unfold away from the fixed shaft, a drill bit being provided on the side of the bottom expansion wing facing away from the fixed shaft, a support assembly being provided between the bottom expansion wing and the fixed shaft, the support assembly being used to support the bottom expansion wing when unfolded, and a slag collection assembly being provided at the bottom of the fixed shaft for collecting and storing large-volume sediment. The present application has the effect of improving the problem of large-volume sediment being difficult to clean.

Description

Technical Field

[0001] The present application relates to the field of punching and bottom-enlarged cast-in-place pile construction technology, and in particular to a bottom-enlarging device and a construction method for punching and bottom-enlarged cast-in-place piles. Background Art

[0002] Currently, the dominant pile types used in various projects include bored cast-in-place piles, sunk cast-in-place piles, prestressed pipe piles, manually excavated piles, and various flexible and semi-flexible piles used for soft foundation treatment (such as mixing piles, powder injection piles, and bulk material piles). However, due to limited pile diameter and low bearing capacity, the construction method of expanded base piles has been adopted in recent years to improve the bearing capacity of pile foundations of uniform diameter.

[0003] A base-enlarged pile is a cast-in-place pile with a larger diameter at the base than the upper shaft. The bearing capacity of a single pile is significantly increased compared to the shaft diameter. Bored base-enlarged cast-in-place piles are a relatively new construction method, an improvement and innovation on bored cast-in-place piles. After the borehole reaches the required bearing layer, a special drill bit is used at the end of the pile to enlarge the diameter, significantly increasing the ultimate bearing capacity of the pile compared to cast-in-place piles without an enlarged head. In actual construction, the base of the cast-in-place pile is enlarged using an enlarged drill bit. This process deposits sediment at the bottom of the pile, and the pile hole is currently typically cleaned using equipment such as a slag extraction barrel or hydraulic pump.

[0004] Regarding the above-mentioned related technologies, the sediment may contain large-volume gravel, mud blocks, etc., which cannot be extracted by hydraulic pumps and are inconvenient to clean. Excessive accumulation of large-volume sediments will affect the final pile strength. Summary of the Invention

[0005] In order to improve the problem that large sediment is difficult to clean, the present application provides a method.

[0006] On the one hand, the present application provides a bottom expansion device for punched and bottom-expanded cast-in-place piles, which adopts the following technical solution: it includes a pile expansion head connected to the end of a drill rod, the pile expansion head includes a fixed shaft and a sleeve sleeved on the fixed shaft, the fixed shaft is connected to the drill rod, and two bottom expansion wings are commonly connected to both sides of the fixed shaft and the sleeve, the bottom expansion wings are folded toward the fixed shaft and unfolded away from the fixed shaft, a drill bit is provided on the side of the bottom expansion wing facing away from the fixed shaft, a support assembly is provided between the bottom expansion wing and the fixed shaft, the support assembly is used to support the bottom expansion wing when the bottom expansion wing is unfolded, and a slag collection assembly is also provided at the bottom of the fixed shaft, and the slag collection assembly is used to collect and store large-volume sediment.

[0007] By adopting the above technical solution, when constructing bored piles with expanded bottoms, after the bored pile holes are punched, the expanded pile head is installed under the drill rod, lowered to the bottom of the bored pile, and driven to rotate. During the rotation of the expanded pile head, the expanded bottom wings are gradually unfolded, and the drill bit on the expanded bottom wings expands the side walls of the pile bottom during the rotation, thereby realizing the expanded bottom construction of the bored pile; large-volume gravel, mud blocks and other sediments generated during the construction process are collected by the slag collecting component, and the large-volume sediments are taken out of the pile hole during the process of lifting the expanded pile head after the construction is completed, thereby achieving the effect of facilitating the cleaning of the large-volume sediments generated during the expanded bottom construction of the bored pile.

[0008] Optionally, the expanded bottom wing includes a first arc rod, a second arc rod and a third arc rod hinged from top to bottom in sequence, the upper end of the first arc rod is hinged to the sleeve, and the lower end of the third arc rod is hinged to the bottom of the fixed shaft. When the first arc rod, the second arc rod and the third arc rod are unfolded, they are spliced ​​into an arc rod body, and the slag collection assembly is arranged on the third arc rod.

[0009] By adopting the above technical solution, when the bottom expansion wings are unfolded, the driving sleeve moves downward, the top end of the first curved rod approaches the bottom end of the third curved rod, and the first curved rod, the second curved rod and the third curved rod are all arched away from the fixed axis, and the bottom expansion of the pile is carried out through the bottom expansion wings; when the bottom expansion is completed, the bottom expansion wings are folded, and the driving sleeve moves upward, and the first curved rod moves away from the third curved rod. At this time, the first curved rod, the second curved rod and the third curved rod are all close to the fixed axis, which facilitates the lowering and removal of the expanded pile head in the pile hole; at the same time, when removing the expanded pile head, due to the arching of the second curved rods on both sides, the expanded pile head is driven to rotate, and the second curved rods on both sides are lifted while rotating, and the drill bits on the second curved rods cut continuous thread grooves on the smooth wall of the pile hole. In the subsequent cast-in-place pile construction process, a mechanical bite state is formed at the interface between the concrete pile and the pile hole wall, thereby increasing the surface friction of the cast-in-place pile and further improving the bearing capacity of the single pile.

[0010] Optionally, the support assembly includes a first support member and a second support member, a first rotating shaft is arranged between the first arc rod and the second arc rod, a second rotating shaft is arranged between the second arc rod and the third arc rod, the first support member is respectively connected to the fixed shaft and the first rotating shaft, and the first support member is used to support the first rotating shaft; the second support member is respectively connected to the fixed shaft and the second rotating shaft, and the second support member is used to support the second rotating shaft.

[0011] By adopting the above technical solution, the hinge between the first arc rod and the second arc rod is supported by the first support member, and the hinge between the second arc rod and the third arc rod is supported by the second support member, thereby preventing the first arc rod, the second arc rod and the third arc rod from moving relative to each other when cutting the inner wall of the pile hole, thereby improving the overall structural stability of the expanded pile head.

[0012] Optionally, the first support member includes a first fixed rod, a first telescopic rod and a first hydraulic cylinder, the first fixed rod is hinged on the sleeve, the end of the first fixed rod extends downward at an angle, the first fixed rod is hollow, the first telescopic rod is slidably set in the first fixed rod, the end of the first telescopic rod is hinged to the first rotating shaft, the first hydraulic cylinder is set in the first fixed rod, and the end of the piston rod of the first hydraulic cylinder is connected to the first telescopic rod.

[0013] By adopting the above technical solution, when the bottom expansion wing is unfolded, the sleeve moves downward. At this time, the first hydraulic cylinder drives the first telescopic rod to move away from the first fixed rod. The first telescopic rod lifts the first arc rod and the second arc rod away from the sleeve, and at the same time supports the first arc rod and the second arc rod when they are under pressure, thereby achieving the effect of facilitating the support of the first arc rod and the second arc rod.

[0014] Optionally, the second support member includes a second fixed rod, a second telescopic rod and a second hydraulic cylinder, the second fixed rod is hinged on the fixed axis, the end of the second fixed rod extends upward at an angle, the second fixed rod is hollow, the second telescopic rod is slidably set in the second fixed rod, the end of the second telescopic rod is hinged to the second rotating shaft, the second hydraulic cylinder is set in the second fixed rod, and the end of the piston rod of the second hydraulic cylinder is connected to the second telescopic rod.

[0015] By adopting the above technical solution, when the bottom expansion wing is unfolded, the piston rod of the second hydraulic cylinder extends, pushing the second telescopic rod to support the second arc rod and the third arc rod, thereby facilitating the support of the second arc rod and the third arc rod; at the same time, the first hydraulic cylinder and the second hydraulic cylinder are started synchronously, so that the bottom expansion wing maintains an arc state when unfolded, thereby facilitating the expansion of the pile bottom while improving the structural strength of the bottom expansion wing.

[0016] Optionally, a sliding groove is provided on the fixed shaft along the length direction, a slider is provided on the sleeve and is slidably arranged in the sliding groove, a third hydraulic cylinder is provided on the fixed shaft and located in the sliding groove, and the piston rod of the third hydraulic cylinder is connected to the slider.

[0017] By adopting the above technical solution, the third hydraulic cylinder is started, and the piston rod of the third hydraulic cylinder is extended or retracted, thereby driving the slider to move in the slide groove, thereby achieving the effect of facilitating the sliding of the sleeve outside the fixed shaft.

[0018] Optionally, the slag collection assembly includes a slag collection net, a support rod and an oblique brace, wherein two support rods are hingedly provided on a fixed axis, and the two support rods are respectively located on both sides of the two third arc-shaped rods, and two oblique braces are also provided on the sleeve, and one end of the oblique brace is hingedly provided on the sleeve, and the other end is hinged to the support rod. The slag collection net is a flexible net, and the slag collection net is conically connected to the inner side of the support rod and the third arc-shaped rod.

[0019] By adopting the above technical solution, when the casing moves downward, the bottom expansion wing unfolds, and the diagonal brace pushes the support rod to unfold. At this time, the slag collecting net is opened at the bottom of the fixed shaft, and the sediment generated by the cutting rock wall of the bottom expansion wing falls and accumulates in the slag collecting net. At the same time, during the rotation of the pile expansion head, fine sediment is discharged through the mesh holes of the slag collecting net, and larger sediment accumulates inside the slag collecting net; in the process of lifting the pile expansion head, the large-volume sediment is trapped in the slag collecting net and lifted up accordingly; this facilitates the cleaning of the large-volume sediment generated during the bottom expansion construction.

[0020] Optionally, a mud pump is further included, the fixed shaft is hollow, a water outlet is provided at the bottom of the fixed shaft, the mud pump is arranged on the ground, and the output end of the mud pump is connected to the fixed shaft.

[0021] By adopting the above technical solution, during the bottom expansion construction process, the mud prepared according to the design requirements is pumped into the pile hole through a mud pump, and a part of the sediment is brought out to the ground through the mud, further improving the sediment cleaning effect.

[0022] Optionally, slag collecting frames are provided on the sleeve and on both sides of the expanded bottom wing.

[0023] By adopting the above technical solution, the sediment is driven up by the mud at the bottom of the pile hole, and some of the large-volume sediment floats up and then sinks and falls into the sediment collecting frame, thereby increasing the collection capacity of large-volume sediment.

[0024] On the other hand, the present application provides a construction method of a punched and bottom-enlarged cast-in-place pile, comprising the following steps:

[0025] S1: Pre-construction preparation, site leveling, measurement and layout, and pile position determination; S2: Installing guard piles at the pile position, burying casing, and drilling with a drilling rig; S3: Bottom expansion step, installing the pile expansion head at the bottom of the drill rod, lowering the pile expansion head to the pile bottom, and gradually unfolding the bottom expansion wings while driving the drill rod to rotate, and expanding the pile bottom with the drill bit on the bottom expansion wings; S4: After bottom expansion is completed, fold the bottom expansion wings, lift the pile expansion head, and clean the large volume of sediment in the slag collection assembly; S5: Extracting small volume sediment from the pile bottom with a hydraulic pump.

[0026] By adopting the above technical solution, after the bottom expansion construction process is completed, the large volume of sediment collected in the slag collecting assembly will be lifted together during the process of lifting the expanded pile head, thereby facilitating the cleaning of the large volume of sediment in the slag collecting assembly.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. During the construction of punched and bottom-enlarged cast-in-place piles, after the punching construction is completed, the pile expansion head is installed under the drill rod, lowered to the bottom of the cast-in-place pile, and driven to rotate. During the rotation of the pile expansion head, the bottom expansion wings are gradually unfolded, and the drill bit on the bottom expansion wings expands the side wall of the pile bottom during the rotation process, thereby achieving the bottom expansion construction of the cast-in-place pile; large-volume gravel, mud blocks and other sediments generated during the construction process are collected by the slag collection component, and when the pile expansion head is lifted after the construction is completed, the large-volume sediments are taken out of the pile hole, so as to facilitate the cleaning of the large-volume sediments generated during the bottom expansion construction of the cast-in-place pile;

[0029] 2. When the bottom expansion wings are deployed, the driving sleeve moves downward, the top end of the first curved rod approaches the bottom end of the third curved rod, and the first, second, and third curved rods are all arched away from the fixed axis, and the bottom expansion of the pile is carried out through the bottom expansion wings; when the bottom expansion is completed, the bottom expansion wings are folded, and the driving sleeve moves upward, the first curved rod moves away from the third curved rod, and the first, second, and third curved rods are all close to the fixed axis, which facilitates the lowering and removal of the expanded pile head in the pile hole;

[0030] 3. When the expanded pile head is taken out, the second arc rods on both sides are arched, and the expanded pile head is driven to rotate. The second arc rods on both sides are lifted while rotating. The second arc rods cut continuous thread grooves on the smooth hole wall of the pile hole. In the subsequent bored pile construction process, a mechanical bite state is formed at the interface between the concrete pile and the pile hole wall, which increases the surface friction of the bored pile and further improves the bearing capacity of the single pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure when the expanded bottom wing is unfolded in an embodiment of the present application.

[0032] Figure 2 It is a schematic diagram for showing the structure of the expansion wings in a partially folded state in an embodiment of the present application.

[0033] Figure 3 It is a cross-sectional view used to illustrate the support component structure in an embodiment of the present application.

[0034] Figure 4 It is a cross-sectional view used to illustrate the fixed shaft structure in an embodiment of the present application.

[0035] Description of reference numerals:

[0036] 1. Expanded pile head; 11. Fixed shaft; 111. Chute; 112. Water outlet; 12. Casing; 121. Slider; 13. Third hydraulic cylinder; 14. Slag collecting frame; 2. Expanded bottom wing; 21. Drill bit; 22. First curved rod; 23. Second curved rod; 24. Third curved rod; 25. First rotating shaft; 26. Second rotating shaft; 3. First support member; 31. First fixed rod; 32. First telescopic rod; 33. First hydraulic cylinder; 4. Second support member; 51. Slag collecting net; 52. Support rod; 53. Diagonal brace. DETAILED DESCRIPTION

[0037] The following is combined with Figure 1-4 This application is described in further detail.

[0038] The present application discloses a bottom enlarging device for a punched and bottom enlarged cast-in-place pile, referring to Figure 1 A bottom expansion device for a punched and bottom-expanded cast-in-place pile includes a pile expansion head 1, which is installed at the end of a drill rod. The pile expansion head 1 includes a fixed shaft 11 and a sleeve 12 sleeved on the fixed shaft 11. The top end of the fixed shaft 11 is threaded, and the fixed shaft 11 is fixedly connected to the drill rod through the thread. Two bottom expansion wings 2 are commonly connected to both sides of the fixed shaft 11 and the sleeve 12. The two bottom expansion wings 2 are directly opposite to each other, that is, the bottom expansion wings 2 are connected to the fixed shaft 11 and the sleeve 12. The bottom expansion wings 2 are folded toward the fixed shaft 11 and unfolded away from the fixed shaft 11. A drill bit 21 is provided on the side of the two bottom expansion wings 2 facing away from the fixed shaft 11. The drill bit 21 is a hard alloy embedded in the bottom expansion wing 2. When the pile expansion head 1 rotates, the drill bit 21 on the bottom expansion wing 2 crushes and cuts the side wall of the pile hole. A support assembly is installed between the bottom expansion wing 2 and the fixed shaft 11. The support assembly is used to support and reinforce the bottom expansion wing 2 when the bottom expansion wing 2 is unfolded. A slag collecting assembly is also installed at the bottom of the fixed shaft 11. The slag collecting assembly is used to collect and store the large volume of sediment generated during the bottom expansion construction. When the pile expansion head 1 is driven to rise, the large volume of sediment collected in the slag collecting assembly is brought out of the pile hole.

[0039] When the bottom of a bored pile is expanded, after the pile hole punching construction is completed, the pile expansion head 1 is installed under the drill rod, and the pile expansion head 1 is lowered to the pile bottom. The pile expansion head 1 is driven to rotate and the bottom expansion wings 2 are driven to unfold at the same time. When the expansion wings are unfolded, the pile wall at the pile bottom is crushed and cut to achieve the bottom expansion construction of the pile bottom; the large volume of sediment generated during the bottom expansion construction is collected by the slag collecting component, and as the pile expansion head 1 is lifted, the large volume of sediment in the slag collecting component is taken out of the pile hole, which solves the problem that it is inconvenient to clean the large volume of sediment when cleaning the pile bottom sediment with equipment such as hydraulic pumps.

[0040] Reference Figure 1 and Figure 4The bottom expansion wing 2 includes a first curved rod 22, a second curved rod 23, and a third curved rod 24, which are hinged from top to bottom. The concave sides of the first curved rod 22, the second curved rod 23, and the third curved rod 24 all face the fixed shaft 11. The upper end of the first curved rod 22 is hingedly connected to the sleeve 12, and the lower end of the third curved rod 24 is hingedly connected to the bottom of the fixed shaft 11. When the first curved rod 22, the second curved rod 23, and the third curved rod 24 are deployed, they are spliced ​​into a complete curved rod body. The slag collection assembly is installed between the two third curved rods 24. When the first curved rod 22, the second curved rod 23, and the third curved rod 24 are deployed, they are spliced ​​into a complete curved rod body, and the support assembly also supports this curved rod body. Since the arch has good compressive resistance, when the bottom expansion wing 2 is subjected to pressure from the pile wall during the bottom expansion construction, the arc structure formed by the first arc rod 22, the second arc rod 23 and the third arc rod 24 has strong compressive resistance, making the overall structure of the bottom expansion wing 2 more stable during the construction process.

[0041] Reference Figure 1 and Figure 2 The support assembly includes a first support member 3 and a second support member 4. A first rotating shaft 25 is installed between the first curved rod 22 and the second curved rod 23, and the first curved rod 22 and the second curved rod 23 are pivotally connected via the first rotating shaft 25. A second rotating shaft 26 is installed between the second curved rod 23 and the third curved rod 24, and the second curved rod 23 and the third curved rod 24 are pivotally connected via the second rotating shaft 26. The first support member 3 is connected to the fixed shaft 11 and the first rotating shaft 25, respectively. When the bottom wing 2 is deployed, the first support member 3 supports the first rotating shaft 25. The second support member 4 is connected to the fixed shaft 11 and the second rotating shaft 26, respectively. When the bottom wing 2 is deployed, the second support member 4 is used to support the second rotating shaft 26.

[0042] Reference Figure 2 The first support member 3 includes a first fixed rod 31, a first telescopic rod 32, and a first hydraulic cylinder 33. The first fixed rod 31 is a hollow rectangular rod with one end open. One end of the first fixed rod 31 is hingedly mounted on the sleeve 12, and the other end extends obliquely downward toward the first rotating shaft 25. The first telescopic rod 32 is also a rectangular rod and is slidably mounted within the first fixed rod 31. The distal end of the first telescopic rod 32 is hingedly mounted to the first rotating shaft 25. The first hydraulic cylinder 33 is mounted within the first fixed rod 31. The longitudinal direction of the first hydraulic cylinder 33 is along the longitudinal direction of the first fixed rod 31. The cylinder body of the first hydraulic cylinder 33 is fixedly connected to the first fixed rod 31, and the distal end of the piston rod of the first hydraulic cylinder 33 is fixedly connected to the first telescopic rod 32.

[0043] Reference Figure 2The second support member 4 includes a second fixed rod, a second telescopic rod, and a second hydraulic cylinder. The second fixed rod is also a hollow rectangular rod with one end open. One end of the second fixed rod is hingedly mounted to the bottom of the fixed shaft 11, and the distal end of the second fixed rod extends upwardly and obliquely toward the second rotating shaft 26. The second telescopic rod is also a rectangular rod and is slidably mounted within the second fixed rod. The distal end of the second telescopic rod is hingedly mounted to the second rotating shaft 26. The second hydraulic cylinder is mounted within the second fixed rod, with its longitudinal direction extending along the longitudinal direction of the second fixed rod. The cylinder body of the second hydraulic cylinder is fixedly connected to the second fixed rod, and the distal end of the piston rod of the second hydraulic cylinder is fixedly connected to the second telescopic rod.

[0044] When the bottom wing 2 is deployed, the sleeve 12 moves downward along the fixed axis 11, the upper end of the first curved rod 22 approaches the lower end of the third curved rod 24, and the first fixed rod 31 and the second fixed rod rotate accordingly. At this time, by activating the first hydraulic cylinder 33 and the second hydraulic cylinder, the first telescopic rod 32 and the second telescopic rod extend and lift the bottom wing 2, supporting the bottom wing 2. When the bottom wing 2 is folded, the sleeve 12 rises, and the first hydraulic cylinder 33 and the second hydraulic cylinder retract synchronously, driving the first curved rod 22, the second curved rod 23, and the third curved rod 24 to move toward the fixed axis 11, reducing the lateral volume of the pile head 1 and facilitating the movement of the pile head 1 within the pile hole.

[0045] Since the first fixing rod 31 extends obliquely downward and the second fixing rod extends obliquely upward, when the bottom expansion wing 2 is unfolded, the first telescopic rod 32 and the second telescopic rod staggeredly press the bottom expansion wing 2 at the current position to avoid dislocation due to pressure during the bottom expansion construction process.

[0046] At the same time, when the pile head 1 is removed after the base expansion construction is completed, the second curved rods 23 on both sides of the fixed shaft 11 arch up, driving the pile head 1 to rotate. The drill bits 21 on the two second curved rods 23 cut grooves in the smooth wall of the pile hole. The second curved rods 23 on both sides rotate and rise, thereby cutting two spiral grooves in the pile wall. During the subsequent pouring of concrete into the pile hole, the concrete fills the spiral grooves. The interface between the concrete pile and the pile hole wall after setting is in a mechanical state of engagement, increasing the surface friction of the cast-in-place pile and further improving the bearing capacity of the single pile.

[0047] Reference Figure 4A slide groove 111 is defined along the length of the fixed shaft 11, and a slider 121 is mounted on the inner wall of the sleeve 12. The slider 121 fits within the slide groove 111 and slides along the groove 111. A third hydraulic cylinder 13 is mounted on the fixed shaft 11 and within the slide groove 111. The cylinder body of the third hydraulic cylinder 13 is fixedly connected to the fixed shaft 11, and the piston rod of the third hydraulic cylinder 13 extends vertically upward and is fixedly connected to the slider 121. When the third hydraulic cylinder 13 is activated, the piston rod of the third hydraulic cylinder 13 extends or retracts, driving the slider 121 to slide within the slide groove 111, thereby driving the sleeve 12 to slide outside the fixed shaft 11.

[0048] Reference Figure 1 and Figure 2 The slag collection assembly includes a slag collection net 51, support rods 52, and diagonal braces 53. Two support rods 52 are hingedly installed at the bottom of the fixed shaft 11. The two support rods 52 are respectively located on both sides of the two third arc-shaped rods 24, and the two support rods 52 are opposite to each other. The upper ends of the two support rods 52 are inclined and extend upward. The support rods 52 are also arc-shaped rod bodies, and the drill bits 21 are also installed on the outer walls of the support rods 52. Two diagonal braces 53 are also installed on the casing 12. The two diagonal braces 53 are respectively opposite to the two support rods 52. One end of the diagonal brace 53 is hingedly installed on the casing 12, and the other end is hinged to the end of the support rod 52. The slag collection net 51 is a flexible net. In this embodiment, the slag collection net 51 is a metal ring net. In other embodiments, the slag collection net 51 can also be a high-strength nylon net or other mesh surface. The slag collecting net 51 is installed around the inner sides of the two support rods 52 and the two third arc-shaped rods 24. When the bottom expansion wings 2 are in the unfolded state, the slag collecting net 51 is in an inverted cone shape.

[0049] The slag collection net 51 is a flexible net. When the bottom expansion wings 2 are deployed, the slag collection net 51 opens, and the sediment produced by the bottom expansion wings 2 cutting the pile hole wall falls into the slag collection net 51. Fine sediment moves through the mesh of the slag collection net 51 to the outside of the slag collection net 51, while large sediment remains and is stored in the slag collection net 51. When the bottom expansion wings 2 are folded, the two support rods 52 and the two third curved rods 24 approach each other, and the slag collection net 51 is no longer in a straight state. The slag collection net 51 is divided into four net pockets. At this time, the large sediment pockets are stored inside the support rods 52 and the third curved rods 24, while some large sediment is stored in the net pockets formed by the slag collection net 51.

[0050] Reference Figure 1-Figure 4The bottom expansion device also includes a mud pump (not shown in the figure). The mud pump is installed on the ground. The fixed shaft 11 is hollow, and the drill rod is also hollow. A water outlet 112 is opened at the bottom of the fixed shaft 11, and the output end of the mud pump is connected to the fixed shaft 11. During the bottom expansion construction, the mud pump is used to inject the prepared mud that meets the design requirements into the pile hole through the fixed shaft 11. The injected mud flows back to the ground through the space between the fixed shaft 11 and the pile hole wall. In this process, the mud sprayed from the bottom of the fixed shaft 11 facilitates the upward removal of sediment out of the pile hole, thereby improving the sediment cleaning effect.

[0051] Reference Figure 1 and Figure 2 A slag collecting frame 14 is installed on the casing 12, located between the bottom expansion wings 2. This slag collecting frame 14 is a hollow, ring-shaped frame with an open top, and is made of metal mesh. It is important to note that the distance between two slag collecting frames 14 on the same horizontal plane is smaller than the distance between two bottom expansion wings 2 on the same horizontal plane. This means that when the bottom expansion wings 2 crush and cut the pile hole wall, the slag collecting frames 14 will not collide with the wall. Large amounts of sediment stirred up by the slurry will sink after rising a certain distance, with the portion that sinks falling into the slag collecting frame 14 and being stored.

[0052] The implementation principle of the bottom expansion device of a punched and bottom-expanded cast-in-place pile in the embodiment of the present application is as follows: after the pile hole punching construction is completed, the pile expansion head 1 is installed to the bottom of the drill rod, and the pile expansion head 1 is lowered to the bottom of the pile hole. During the process of driving the pile expansion head 1 to rotate, the bottom expansion wings 2 are gradually unfolded, and the bottom expansion wings 2 crush and cut the pile hole wall to perform bottom expansion construction; during the bottom expansion construction process, the large volume of sediment generated falls into the slag collecting net 51. When the bottom expansion construction is completed, the pile expansion head 1 is driven to rise, and the slag collecting net 51 and the large volume of sediment therein are moved out of the pile hole.

[0053] The present application also discloses a construction method based on a punching cast-in-place pile bottom expansion device, comprising the following steps:

[0054] S1: Preparation before construction: level the foundation where the piles are to be driven, measure and lay out the lines according to the design requirements, and determine the positions of the cast-in-place piles;

[0055] S2: Drive the guard pile at the designed pile position, press the steel casing into the soil using hydraulic equipment, move the drilling rig to the pile hole position, and drill with the drilling rig;

[0056] S3: Bottom expansion step: After the pile hole is drilled to the target depth, the drill rod is lifted, and the pile expansion head 1 is installed at the bottom of the drill rod. The pile expansion head 1 is then lowered to the pile bottom. The bottom expansion wings 2 are gradually unfolded during the rotation of the drill rod. The drill bit 21 on the bottom expansion wings 2 crushes and cuts the pile hole wall to expand the pile bottom;

[0057] S4: After the bottom expansion is completed, the bottom expansion wings 2 are folded and the pile head 1 is lifted. During the lifting process, the pile head 1 is driven to rotate so that the second arc-shaped rods 23 on both sides cut double spiral grooves on the pile hole wall;

[0058] S5: Cleaning the large volume of sediment collected and stored in the slag collecting net 51 and the slag collecting box;

[0059] S6: Extract the small volume of sediment at the bottom of the pile through a hydraulic pump.

[0060] Finally, it should be noted that in the description of this application, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0061] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A bottom enlarging device for a punched and bottom enlarged cast-in-place pile, characterized by: The invention comprises an expansion pile head (1) connected to the end of a drill rod, the expansion pile head (1) comprising a fixed shaft (11) and a sleeve (12) sleeved on the fixed shaft (11), the fixed shaft (11) being connected to the drill rod, two expansion bottom wings (2) being commonly connected to both sides of the fixed shaft (11) and the sleeve (12), the expansion bottom wings (2) being folded toward the fixed shaft (11) and unfolded away from the fixed shaft (11), a drill bit (21) being provided on the side of the expansion bottom wing (2) facing away from the fixed shaft (11), a support assembly being provided between the expansion bottom wing (2) and the fixed shaft (11), the support assembly being used to support the expansion bottom wing (2) when the expansion bottom wing (2) is unfolded, and a slag collecting assembly being provided at the bottom of the fixed shaft (11), the slag collecting assembly being used to collect and store large-volume sediment; The bottom expansion wing (2) comprises a first arc rod (22), a second arc rod (23) and a third arc rod (24) which are hinged in sequence from top to bottom, the upper end of the first arc rod (22) is hinged to the sleeve (12), the lower end of the third arc rod (24) is hinged to the bottom of the fixed shaft (11), the first arc rod (22), the second arc rod (23) and the third arc rod (24) are spliced ​​into an arc rod body when unfolded, and the slag collecting assembly is arranged on the third arc rod (24); the support assembly comprises a first support member (3) and a second support member (4 ), a first rotating shaft (25) is provided between the first arc-shaped rod (22) and the second arc-shaped rod (23), a second rotating shaft (26) is provided between the second arc-shaped rod (23) and the third arc-shaped rod (24), the first supporting member (3) is connected to the fixed shaft (11) and the first rotating shaft (25) respectively, and the first supporting member (3) is used to support the first rotating shaft (25); the second supporting member (4) is connected to the fixed shaft (11) and the second rotating shaft (26) respectively, and the second supporting member (4) is used to support the second rotating shaft (26); The slag collecting assembly comprises a slag collecting net (51), a support rod (52) and an oblique brace (53), wherein two support rods (52) are hingedly arranged on the fixed shaft (11), and the two support rods (52) are respectively located on both sides of the two third arc-shaped rods (24), and two oblique braces (53) are also arranged on the sleeve (12), and one end of the oblique brace (53) is hingedly arranged on the sleeve (12) and the other end is hingedly connected to the support rod (52), and the slag collecting net (51) is a flexible net, and the slag collecting net (51) is conically connected around the inner side of the support rod (52) and the third arc-shaped rod (24); The support rods (52) are hinged on both sides of the fixed shaft (11) and are linked to the unfolding action of the bottom expansion wings (2); when the bottom expansion wings (2) are unfolded, the support rods (52) extend outwards and tighten the slag collection net (51), forming a conical collection space for real-time collection of large-volume sediment generated during the bottom expansion process.

2. The bottom enlarging device for a punched and bottom enlarged cast-in-place pile according to claim 1, characterized in that: The first support member (3) comprises a first fixed rod (31), a first telescopic rod (32) and a first hydraulic cylinder (33); the first fixed rod (31) is hingedly arranged on the sleeve (12); the end of the first fixed rod (31) extends obliquely downward; the first fixed rod (31) is hollow; the first telescopic rod (32) is slidably arranged in the first fixed rod (31); the end of the first telescopic rod (32) is hinged to the first rotating shaft (25); the first hydraulic cylinder (33) is arranged in the first fixed rod (31); and the end of the piston rod of the first hydraulic cylinder (33) is connected to the first telescopic rod (32).

3. The bottom enlarging device for a punched and bottom enlarged cast-in-place pile according to claim 1, characterized in that: The second support member (4) includes a second fixed rod, a second telescopic rod and a second hydraulic cylinder, the second fixed rod is hingedly arranged on the fixed shaft (11), the end of the second fixed rod extends obliquely upward, the second fixed rod is hollow, the second telescopic rod is slidably arranged in the second fixed rod, the end of the second telescopic rod is hinged to the second rotating shaft (26), the second hydraulic cylinder is arranged in the second fixed rod, and the end of the piston rod of the second hydraulic cylinder is connected to the second telescopic rod.

4. The bottom enlarging device for a punched and bottom enlarged cast-in-place pile according to claim 1, characterized in that: A sliding groove (111) is provided on the fixed shaft (11) along the length direction, a sliding block (121) is provided on the sleeve (12) and is slidably arranged in the sliding groove (111), a third hydraulic cylinder (13) is provided on the fixed shaft (11) and is located in the sliding groove (111), and a piston rod of the third hydraulic cylinder (13) is connected to the sliding block (121).

5. The bottom enlarging device for a punched and bottom enlarged cast-in-place pile according to claim 1, characterized in that: It also includes a mud pump, the fixed shaft (11) is hollow, a water outlet (112) is provided at the bottom of the fixed shaft (11), the mud pump is arranged on the ground, and the output end of the mud pump is connected to the fixed shaft (11).

6. The bottom enlarging device for a punched and bottom enlarged cast-in-place pile according to claim 1, characterized in that: Slag collecting frames (14) are provided on the sleeve (12) and on both sides of the expanded bottom wing (2).

7. A construction method for a bottom enlargement device for a punched and bottom enlarged cast-in-place pile according to claim 6, characterized in that: The following steps are involved: S1: Preparation before construction, leveling the site, measuring and setting out the lines, and determining the pile positions; S2: Drive the pile guard at the pile position, bury the casing, and drill with a drilling rig; S3: bottom expansion step, installing the pile expansion head (1) at the bottom of the drill rod, lowering the pile expansion head (1) to the pile bottom, driving the drill rod to rotate while gradually unfolding the bottom expansion wings (2), and expanding the pile bottom through the drill bit (21) on the bottom expansion wings (2); S4: After the bottom expansion is completed, the bottom expansion wings (2) are folded, the pile expansion head (1) is lifted, and the large volume of sediment in the slag collection assembly is cleaned; S5: Extract small volume sediment from the pile bottom through hydraulic pump.

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