An integrated device and construction method for expanding the bottom and diameter of a pipe pile joint

Abstract

The present invention discloses an integrated device and construction method for expanding the bottom and diameter of pipe pile splicing, belonging to the field of building construction. In this integrated device, multiple sections of pipe piles are connected by a diameter-expanding joint and a pipe pile joint and then driven into the soil layer. Then, a hole-expanding device is used to expand the diameter-expanding joint in sequence to form a diameter expansion. Subsequently, a grouting machine is connected to a bladder-type bottom-expanding device through a grouting pipe, and a certain amount of slurry is injected and solidified to form a bottom expansion. The present invention can improve the side resistance and end resistance of the pile, significantly improve the bearing capacity of the pile foundation, especially the uplift bearing capacity mainly based on the side friction of the pile can be significantly improved. Therefore, the pile length and the number of piles can be reduced, thereby reducing the project cost.

Description

Technical Field

[0001] The present invention relates to the field of building foundation construction, and particularly relates to a pipe pile joint pile bottom expanding and diameter expanding integrated device and a construction method thereof. Background Art

[0002] Pile foundations are currently the most widely used foundation form. Their bearing capacity consists of the side friction resistance between the pile body and the surrounding soil and the end bearing force of the pile tip in the bearing stratum. Generally speaking, the bearing capacity of pile foundations can be improved by increasing the pile length and pile diameter. However, the efficiency of improving the bearing capacity of pile foundations by this method is not high. Therefore, people have invented the bottom expanding method and the diameter expanding method to improve the bearing capacity of pile foundations, and this method is widely used in cast-in-place piles.

[0003] For example, in the invention patent with the application number CN201310056968.1, a dynamic compaction vibration composite bottom expanding pile driver and a construction method of a dynamic compaction vibration composite bottom expanding pile are provided. It conducts end dynamic compaction bottom expansion by filling compaction expanding auxiliary materials and forms an enlarged head by pouring concrete and dynamic compaction. This bottom expanding pile can improve the single pile bearing capacity. In addition, in the utility model patent with the application number CN201320162595.1, a variable diameter bottom expanding pile foundation is provided. The lower side of the pile body is provided with pile wings. The extending direction of the pile wings is perpendicular to the axis of the pile body. The pile wings are arranged in a radial shape around the pile body from the axis of the pile body. The pile wings are equally angularly distributed among the wings on the same horizontal section of the pile body. The wings are trapezoidal in the upper part and triangular in the lower part along the longitudinal direction of the pile body, and the upper and lower parts of the bottom expanding pile tip are frustum-shaped. Theoretically, this variable diameter bottom expanding pile foundation can also further improve the bearing capacity of the pile foundation.

[0004] However, for such bottom expanding or diameter expanding pile foundations, on-site construction is often required, with low construction efficiency and it is difficult to ensure construction quality. With the popularization of precast pipe piles, there has gradually emerged the practice of combining the bottom expanding or diameter expanding structure with precast pipe piles. For example, the invention patent with the application number CN201710221108.7 provides a precast bottom expanding variable diameter pile for treating soft soil foundation and a construction method thereof, and the utility model patent with the application number CN201721065866.6 discloses an enlarged diameter cement mixing pile - precast pile foundation. However, in the construction of such precast pipe piles, static or dynamic methods are usually used to drive the precast piles into the soil layer. Due to the too large end resistance of the bottom expanding pipe pile and the side resistance of the diameter expanding pipe pile, the construction difficulty during the pile pressing process has greatly increased, which has been restricting the development of precast bottom expanding pipe piles and diameter expanding pipe piles.

[0005] Therefore, how to achieve the bottom expansion and diameter expansion of precast pipe piles while reducing the construction difficulty during the pile pressing process is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0006] In view of the various problems existing in the under-reamed pipe piles and expanded-diameter pipe piles in the above-mentioned background art, the present invention provides a pipe pile jointing, under-reaming and expanded-diameter integration device and a construction method thereof, so as to reduce the difficulty of the construction technology of under-reamed and expanded-diameter pipe piles.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a pipe pile jointing, under-reaming and expanded-diameter integration device, which includes a pipe pile, an expanded-diameter joint, a pipe pile joint, an under-reamer, a pile tip connecting collar, a bladder-type under-reaming device and a pile tip;

[0009] Multiple sections of pipe piles are spliced vertically in sequence to form a pile body; on the splicing end faces of any two adjacent pipe piles, a pipe pile joint is respectively fixed, and the two pipe pile joints are clamped and fixed by the expanded-diameter joint, so that two adjacent pipe piles form a reliable connection; the expanded-diameter joint is provided with a variable-diameter mechanism capable of expanding and contracting radially along the cross-section of the pile body, and the variable-diameter mechanism has a contracted state completely retracted into the pile body and an expanded state protruding from the pile body;

[0010] The under-reamer is used to apply a radial driving force along the cross-section of the pile body to the variable-diameter mechanism, so as to convert the variable-diameter mechanism from the contracted state to the expanded state;

[0011] The bottommost section of the pipe pile in the pile body is installed on the pile tip through the pile tip connecting collar; the bladder-type under-reaming device is installed above the pile tip, and is provided with a grouting port;

[0012] The grouting port is used to connect to an external grouting machine through a grouting pipe, so as to press the grout into the expandable bladder of the bladder-type under-reaming device, so that the expandable bladder is grouted and expanded to push the pile tip away from the bladder-type under-reaming device and further squeeze the surrounding soil at the pile bottom by the bladder to form a pile tip enlarged head.

[0013] As a preference of the above first aspect, the expanded-diameter joint includes an upper end plate, a lower end plate, connecting rib plates, expanded-diameter blades and connecting bolts; the upper end plate and the lower end plate are arranged in parallel at intervals, and a connecting structure capable of bearing the load in the direction perpendicular to the end plates is formed by clamping and fixing a plurality of connecting rib plates therebetween; the expanded-diameter blades are assembled corresponding to the connecting rib plates one by one, each expanded-diameter blade includes a fan-shaped ring plate and an arc-shaped limiting plate, and a through-channel is opened on the fan-shaped ring plate, the fan-shaped ring plate is installed between the upper end plate and the lower end plate, and the fan-shaped ring plate is sleeved outside the connecting rib plate through the through-channel to form a sliding pair for restricting the radial movement of the fan-shaped ring plate, the size of the arc-shaped limiting plate is larger than the gap between the upper end plate and the lower end plate, and when the arc-shaped limiting plate moves outwards to the limit position, it can limit its further outward movement; connecting pieces for connecting the pipe pile joints are respectively arranged on the outer plate surfaces of the upper end plate and the lower end plate.

[0014] Preferably, as for the first aspect described above, the pipe pile joint includes an end plate and end plate holes. The end plate is fixed to the splicing end face of the pipe pile. The end plate holes are evenly arranged along the circumference of the end plate, and the number and positions thereof are the same as those of the connecting members on the diameter-expanded joint. The connecting members can be fixedly fitted into the end plate holes.

[0015] Preferably, as for the first aspect described above, the connecting members on the upper end plate and the lower end plate are connecting bolts. The threaded section of the connecting bolt is fixed to the corresponding end plate, and its bolt head is spaced from the surface of the end plate. The end plate holes on the end plate are stepped holes, and the stepped holes have a first hole area and a second hole area that communicate with each other. The hole size of the first hole area can allow the bolt head to extend into it, and the bolt head can move from the first hole area to the second hole area, but the hole size of the second hole area cannot directly allow the bolt head to break away from the second hole area.

[0016] Preferably, as for the first aspect described above, the hole expander includes a driving mechanism, multiple groups of cross arms, and an expanding end plate. In each group of cross arms and expanding end plate, the expanding end plate is connected to the driving mechanism through the cross arms. Driven by the driving mechanism, all the expanding end plates synchronously expand and contract to form a gathering state and an expanding state. In the gathering state, the size of all the expanding end plates after gathering can integrally extend into the enclosed space of the arc-shaped limiting plates of all the diameter-expanded blades in the contracted state. In the expanding state, the size of all the expanding end plates after unfolding can make the arc-shaped limiting plates of all the diameter-expanded blades support against the inner rings of the upper end plate and the lower end plate after outward expansion.

[0017] Preferably, as for the first aspect described above, the pile tip connecting collar is composed of a first annular section, a second annular section, a top surface closing the top of the first annular section, and a stepped surface connecting the two annular sections, and is integrally in a convex shape with an open bottom. The outer diameter of the first annular section is consistent with the inner diameter of the pipe pile, and the outer diameter of the second annular section is consistent with the outer diameter of the pipe pile. In the assembled state, the pipe pile joint at the end of the pipe pile is supported on the stepped surface, the first annular section extends into the inner cavity of the pipe pile, the second annular section is detachably buckled on the pile tip, and the top surface, the first annular section, and the top surface of the pile tip enclose a containing space. The capsule-type bottom-expanded device includes an expandable capsule and a capsule joint. The expandable capsule is placed in the containing space. The capsule joint extends out of the pile tip connecting collar through a through hole opened on the top surface for injecting grouting liquid into the expandable capsule.

[0018] Preferably, as for the first aspect described above, the end of the outlet end of the grouting pipe adopts a magnetic joint that can be connected and locked self-locking with the capsule joint.

[0019] Preferably, as the first aspect described above, it further includes a centering device for keeping the pipeline extending into the pipe pile centered all the time; the centering device includes a sleeve and at least three telescopic rods. The sleeve is used for annularly sleeving and fixing on the pipeline extending into the pipe pile, and all the telescopic rods are vertically fixed on the sleeve at equal circumferential angles. The telescopic rods can synchronously expand and contract according to the inner diameter size of the pipe pile, so that the sleeve and the pipeline passing through the inside thereof are always centered during the up-and-down movement in the pipe pile.

[0020] In a second aspect, the present invention provides a construction method for pipe pile joint connection, bottom expansion and diameter expansion by using the integrated device described in any one of the above first aspects, which includes:

[0021] S1. Determine the pile position coordinates according to the design drawing, and place the pile tip on the ground at the coordinate point; install the capsule bottom expansion device in the pile tip connecting collar, keep the capsule joint extending out of the pile tip connecting collar through the through hole opened on the top surface, and then buckle and fix the pile tip connecting collar with the installed capsule bottom expansion device on the pile tip; respectively fix a pipe pile joint on the splicing end faces between all the pipe piles to be connected.

[0022] S2. Vertically assemble the first pipe pile on the pile tip connecting collar, and make the first annular section on the upper part of the pile tip connecting collar insert into the pipe pile; then use the pile driving equipment to drive the first pipe pile into the soil layer, and only keep the pile top part exposed on the ground.

[0023] S3. Place an expansion joint on the pipe pile joint at the pile top of the pipe pile exposed on the ground, adjust the position so that the bolt heads of the connecting bolts on the lower end plate extend into the first hole area of the end plate holes of the pipe pile joint one by one, and then rotate the expansion joint so that all the bolt heads of the connecting bolts move from the first hole area to the second hole area to complete the connection between the expansion joint and the lower pipe pile; then place another pipe pile on the upper end plate of the expansion joint, adjust the position so that the bolt heads of the connecting bolts on the upper end plate extend into the first hole area of the end plate holes of the pipe pile joint one by one, and then rotate the upper pipe pile so that all the bolt heads of the connecting bolts move from the first hole area to the second hole area to complete the connection between the expansion joint and the upper pipe pile; after completing the connection and fixation of the upper and lower two pipe piles, continue to press the pile downwards so that the upper pipe pile is driven into the soil layer and only keep the pile top part exposed on the ground.

[0024] S4. Continuously repeat step S3 until all the pipe piles are driven into the soil layer.

[0025] S5. After all the pipe piles are driven into the soil layer, lower the expander with all the reaming end plates in the gathered state to the position of the first reaming joint. Start the driving mechanism to synchronously extend all the reaming end plates outward to the expanded state. During the unfolding process of each reaming end plate, it can respectively push the corresponding reaming blades outward to move, so that all the reaming blades in the first reaming joint synchronously extend out of the pile body to form a reaming structure for improving the bearing capacity of the pile foundation. Then, contract all the reaming end plates back to the gathered state again, lower them to the position of the next reaming joint and transform it into the reaming state. Keep repeating until all the reaming joints are transformed into the reaming state, and then take out the expander.

[0026] S5. Sheath the casing of the centering device on the grouting pipe connected to the grouting machine, and adjust the length of the telescopic rod according to the inner diameter of the pipe pile so that the length of all the telescopic rods is equal to the difference between the inner radius of the pipe pile and the outer radius of the casing. Then lower the grouting pipe with the centering device to the bottom of the pile and connect it to the bladder joint. Start the grouting machine to inject the grouting slurry under pressure into the expandable bladder. Under the action of the grouting pressure, the expandable bladder expands, thereby pushing the pile tip away from the pile tip connecting collar, and continuing to extend out of the bottom of the pile to squeeze and expand the surrounding soil. After the grouting is completed, pull out the centering device and the grouting pipe. After the cement slurry solidifies, a pile tip enlarged head for improving the bearing capacity of the pile bottom is formed.

[0027] As a preference of the above first aspect, the maximum expanded diameter of the expandable bladder is 1.5 - 2 times the outer diameter of the pipe pile.

[0028] As a preference of the above first aspect, the grouting pressure of the grouting machine is 0.5 - 2 MPa.

[0029] As a preference of the above first aspect, the grouting liquid uses cement slurry or fine aggregate concrete, and is controlled by both the grouting volume and the grouting pressure. When any one reaches the design requirement, the grouting can be stopped.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) The present invention can improve the shaft resistance and the tip resistance of the pile, and can greatly improve the bearing capacity of the pile foundation. Especially, the uplift bearing capacity mainly based on the shaft friction of the pile can be significantly improved. Therefore, the pile length and the number of piles can be reduced, thereby reducing the project cost and saving the construction cost.

[0032] 2) The bottom expansion and diameter expansion adopted by the present invention do not change the diameter of the pipe pile body, and the traditional pipe pile production process can be used, which is easy to promote. In addition, when constructing the pipe pile, the diameter of the pile body is the same up and down, which will not increase the driving difficulty of the pile and is convenient for on-site construction.

[0033] 3) The reaming joint of the present invention adopts the currently widely used rotary anchoring method, and is anchored and connected to the pipe pile end plate by rotation, without the need to change the existing pipe pile connection process, with good versatility and convenient construction. Brief Description of the Drawings

[0034] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0035] Figure 1 is a schematic structural diagram of an integrated device for expanding the bottom and diameter of a pipe pile joint;

[0036] Figure 2 is a three-dimensional schematic diagram of the contracted state of the diameter-expanding joint.

[0037] Figure 3 is a planar schematic diagram of the contracted state of the diameter-expanding joint.

[0038] Figure 4 is a sectional schematic diagram of the contracted state of the diameter-expanding joint.

[0039] Figure 5 is a three-dimensional schematic diagram of the diameter-expanding blade.

[0040] Figure 6 is a planar schematic diagram of the expanded state of the diameter-expanding joint.

[0041] Figure 7 is a three-dimensional schematic diagram of the expanded state of the diameter-expanding joint.

[0042] Figure 8 is a planar schematic diagram of the pipe pile joint.

[0043] Figure 9 is a schematic diagram of the contracted state of the hole-expanding device.

[0044] Figure 10 is a schematic diagram of the expanded state of the hole-expanding device.

[0045] Figure 11 is a schematic diagram of the contracted state of the hole-expanding device inside the pipe pile.

[0046] Figure 12 is a schematic diagram of the expanded state of the hole-expanding device inside the pipe pile.

[0047] Figure 13 is a longitudinal sectional schematic diagram of the pile tip connecting collar.

[0048] Figure 14 is a planar schematic diagram of the reassembled state of the pile tip connecting collar and the pile tip.

[0049] Figure 15 is a partially enlarged schematic diagram of the bladder-type expanded bottom pile tip of the pipe pile.

[0050] Figure 16 is a three-dimensional schematic diagram of the centering device.

[0051] Figure 17It is a schematic diagram of the partial construction state of the integrated device for expanding the bottom and diameter of pipe pile joint piles.

[0052] The reference numerals in the figure are: pipe pile 1, diameter-expanding joint 2, upper end plate 201, lower end plate 202, connecting rib plate 203, diameter-expanding blade 204, connecting bolt 205, pipe pile joint 3, end plate 301, end plate hole 302, hole-expanding device 4, hydraulic cylinder 401, hydraulic piston rod 402, first hydraulic pipe 403, second hydraulic pipe 404, cross arm 405, stopper 406, pin shaft 407, fixed end block 408, sliding end block 409, hole-expanding end plate 410, pile tip connecting collar 5, top surface 501, first annular section 502, stepped surface 503, second annular section 504, bladder-type bottom-expanding device 6, expandable bladder 601, bladder joint 602, grouting liquid 603, grouting pipe 7, pile tip 8, pile tip plate 801, bottom seal 802, pile tip chamfer 803, centering device 9, casing 901, telescopic rod 902, grouting machine 10. Detailed implementation manners

[0053] To make the above objects, features and advantages of the present invention more obvious and understandable, the following describes the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined correspondingly without conflict.

[0054] In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it can be directly connected to the other element or indirectly connected, that is, there is an intermediate element. On the contrary, when an element is referred to as being "directly" connected to another element, there is no intermediate element.

[0055] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features.

[0056] As Figure 1As shown in the figure, in a preferred embodiment of the present invention, a pipe pile jointing, bottom expanding and diameter expanding integrated device is provided. The core components thereof include a pipe pile 1, a diameter expanding joint 2, a pipe pile joint 3, an under-reamer 4, a pile tip connecting collar 5, a bladder type bottom expanding device 6 and a pile tip 8. In this integrated device, multiple sections of pipe piles 1 are connected by the diameter expanding joint 2 and the pipe pile joint 3 and then driven into the soil layer. Then, the under-reamer 4 is used to expand the diameter expanding joint 2 in sequence to form diameter expansion. Then, a grouting machine 10 is connected to the bladder type bottom expanding device 6 through a grouting pipe 7, and a certain amount of grout is injected and solidified to form bottom expansion. The following describes in detail the specific structures of each component and the connection and cooperation relationships therebetween.

[0057] In the precast pile body structure of the present invention, the pile body is composed of multiple sections of pipe piles 1 precast in a factory and spliced vertically in sequence. The length of the entire pile body can be adjusted by combining different numbers of pipe piles 1. For the convenience of description, in the present invention, the end face of a section of pipe pile 1 that needs to be spliced with another section of pipe pile 1 or the pile tip 8 is called the splicing end face.

[0058] In order to ensure convenient and reliable connection between two sections of pipe piles 1, a pipe pile joint 3 is fixed on each of the splicing end faces of any two adjacent pipe piles 1, and the pipe pile joints 3 on the two splicing end faces are clamped and fixed by the diameter expanding joint 2, so as to form a reliable connection between two adjacent pipe piles 1. At the same time, in order to form a corresponding diameter expansion structure, a variable diameter mechanism capable of expanding and contracting radially along the cross-section of the pile body is provided in the diameter expanding joint 2. The variable diameter mechanism has a contracted state completely retracted into the pile body and an expanded state protruding from the pile body.

[0059] Since the contracted state and the expanded state of the variable diameter mechanism in the diameter expanding joint 2 need to be pushed by an external force, an under-reamer 4 matching the diameter expanding joint 2 is also provided in the present invention. The under-reamer 4 can apply a radial pushing force along the cross-section of the pile body to the variable diameter mechanism, so as to convert the variable diameter mechanism from the contracted state to the expanded state.

[0060] In addition, in order to reduce the resistance during the driving process of the pile body, referring to the traditional practice, the present invention also provides a pile tip 8 at the bottommost section of pipe pile 1 in the pile body. However, in order to form an enlarged bottom at the bottom of the pile body, the bottommost section of pipe pile 1 in the pile body needs to be installed on the pile tip 8 through a pile tip connection hoop 5, and a bladder-type bottom enlargement device 6 is installed above the pile tip 8. The bladder-type bottom enlargement device 6 is a special bottom enlargement device with an expandable bladder inside, and it is provided with a grouting port. This grouting port is used to connect to an external grouting machine 10 through a grouting pipe 7, so as to press the grout into the expandable bladder of the bladder-type bottom enlargement device 6. After the expandable bladder is grouted and expanded, it pushes the pile tip 8 away from the bladder-type bottom enlargement device 6. After the pile tip 8 is separated from the bladder-type bottom enlargement device 6, it can provide space for the further expansion of the expandable bladder. Thus, when the expandable bladder continues to expand, it squeezes and expands the surrounding soil at the pile bottom. After the final grouting slurry solidifies, a pile end enlarged head can be formed.

[0061] The specific structural forms of the above-mentioned pipe pile 1, diameter expansion joint 2, pipe pile joint 3, hole expander 4, pile tip connection hoop 5, bladder-type bottom enlargement device 6 and pile tip 8 can be reasonably adjusted and optimized according to actual needs. The preferred practices of each of them in the embodiments of the present invention will be described in detail below.

[0062] As a preferred form of the embodiment of the present invention, the above-mentioned pipe pile 1 can be prefabricated into pipe sections meeting the strength according to certain parameters in the factory. Its processing method is similar to that of common precast pipe piles and will not be elaborated here. Moreover, in order to be applicable to different construction scenarios, the above-mentioned pipe pile 1 can also be designed with different diameters and different length types. Pile bodies with different design parameters can be directly connected by combining pipe piles 1 with different parameters.

[0063] As another preferred form of the embodiment of the present invention, as Figure 2 and Figure 3 shown, the above-mentioned diameter expansion joint 2 includes an upper end plate 201, a lower end plate 202, connecting rib plates 203, diameter expansion blades 204 and connecting bolts 205. The upper end plate 201 and the lower end plate 202 are arranged in parallel, and there is a certain interval between them for installing the connecting rib plates 203. In this embodiment, both the upper end plate 201 and the lower end plate 202 are circular rings. As Figure 4 shown, there are a total of 4 connecting rib plates 203, which are arranged at equal angles in the circumferential direction of the circular ring. The top of each connecting rib plate 203 is connected to the upper end plate 201, and the bottom is connected to the lower end plate 202, so that a connecting structure capable of bearing the load in the direction perpendicular to the end plate is formed between the upper end plate 201 and the lower end plate 202 through 4 connecting rib plates 203. In this embodiment, the variable diameter mechanism capable of expanding and contracting radially along the cross-section of the pile body in the aforementioned diameter expansion joint 2 is realized by the diameter expansion blades 204.

[0064] The diameter expansion blades 204 are assembled in one-to-one correspondence with the connecting rib plates 203. AsFigure 5 As shown, each diameter-expanding blade 204 includes a fan-shaped annular plate and an arc-shaped limiting plate. A slideway penetrating the plate body is provided on the fan-shaped annular plate. The width of the slideway is slightly larger than the thickness of the connecting rib plate 203, and the outer end of the slideway is spaced from the outer arc edge of the fan-shaped annular plate. The fan-shaped annular plate is installed between the upper end plate 201 and the lower end plate 202, and the fan-shaped annular plate is sleeved outside the connecting rib plate 203 through the slideway, thereby forming a sliding pair that restricts the radial movement of the fan-shaped annular plate. Therefore, when the variable-diameter mechanism is in the contracted state, the diameter-expanding blades 204 are completely contracted between the upper end plate 201 and the lower end plate 202, and their ends do not extend out of the outer ring surfaces of the upper end plate 201 and the lower end plate 202, as Figure 3 shown. When the variable-diameter mechanism needs to be changed to the diameter-expanding state, the diameter-expanding blades 204 can be radially pushed by an external force, so that they move outward under the limiting action of the connecting rib plate 203, so that the outer edges of the blades extend out of the outer ring surfaces of the upper end plate 201 and the lower end plate 202. In the actual process, since the outside of the pile body is generally the soil around the pile, in order to facilitate the diameter-expanding blades 204 to change to the diameter-expanding state, the outer ring surface of the diameter-expanding blades 204 can be chamfered into a sharp angle form. In addition, the purpose of setting the arc-shaped limiting plate at the inner arc edge of the fan-shaped annular plate is to prevent the diameter-expanding blades 204 from expanding excessively and detaching from the upper end plate 201 and the lower end plate 202, and to control the limit position of the outward movement of the diameter-expanding blades 204. The arc-shaped limiting plate is arranged perpendicular to the fan-shaped annular plate. When all the arc-shaped limiting plates are in the contracted state in the assembled state of the diameter-expanding joint 2, it is preferably to form a complete cylindrical surface. The size of the limiting plate should be larger than the gap between the upper end plate 201 and the lower end plate 202, and when the arc-shaped limiting plate moves outward to the limit position, it can fit the inner arc sides of the upper end plate 201 and the lower end plate 202 to limit its further outward movement. As Figure 6 and Figure 7 shown, it shows the shape of the four diameter-expanding blades 204 in the variable-diameter mechanism when they are in the diameter-expanding state. At this time, its equivalent diameter is significantly larger than the outer diameter of the pile body, and the four diameter-expanding blades 204 are horizontally inserted into the soil layer, forming a reliable diameter-expanding structure, which can greatly increase the bearing capacity and uplift resistance of the pile body.

[0065] In addition, in the present invention, the function of the upper end plate 201 is to connect the pile joint 3 at the bottom of a pipe pile 1 located above, and the function of the lower end plate 202 is to connect the pile joint 3 at the top of a pipe pile 1 located below. In order to facilitate the connection between the end plate and the pile joint 3, connecting members for connecting the pile joint 3 can be respectively provided on the outer plate surfaces of the upper end plate 201 and the lower end plate 202. However, the specific form of the connecting member can be reasonably designed according to the specific form of the pile joint 3

[0066] Of course, it should be noted that, although the number of the diameter-expanding blades 204 and the number of the connecting ribs 203 in the above embodiment are both 4, in other embodiments, they can be adjusted according to actual conditions, with a minimum of 3 and also more than 4.

[0067] As another preferred embodiment of the present invention, Figure 8 As shown, the pipe pile joint 3 includes an end plate 301 and an end plate hole 302. The pipe pile joint 3 is fixed to the joint end face of the pipe pile 1 through the end plate 301, and the fixation can be directly prefabricated during factory processing. In addition, the end plate 301 is connected and matched with the connectors on the upper end plate 201 and the lower end plate 202 by opening end plate holes 302 evenly arranged along the circumference of the end plate. In order to ensure matching installation, the number and position of the end plate holes 302 are the same as the number of connectors on the expansion joint 2, so that the connectors on the upper end plate 201 and the lower end plate 202 can be just matched and fixed in each end plate hole 302.

[0068] As another preferred form of the embodiment of the present invention, the connecting member on the upper end plate 201 and the lower end plate 202 is a connecting bolt 205, and the threaded section of the connecting bolt 205 is fixed on the upper end plate 201 or the lower end plate 202, but the bolt head needs to keep a distance from the end plate surface. The connecting bolt 205 can be connected to the upper end plate 201 and the lower end plate 202 by welding or threading. The end plate hole 302 on the end plate 301 adopts a reducing hole, and the reducing hole has a first hole area and a second hole area connected, wherein the hole size of the first hole area can be inserted into the bolt head of the connecting bolt 205, and when the connecting bolt 205 moves relative to the upper end plate 201 or the lower end plate 202, the bolt head can move from the first hole area to the second hole area. However, in order to ensure the realization of the connection and fixing function, the hole size of the second hole area needs to ensure that the bolt head cannot be directly detached from the second hole area. It is particularly important to note that since the size of the bolt head is larger than the hole size of the second hole area, but the bolt head needs to be able to move from the first hole area to the second hole area, the second hole area is actually a hole with an inner cavity, and the hole size is smaller than the bolt head size, but the inner cavity below the hole can still accommodate the bolt head.

[0069] See also Figure 8As shown in the figure, the variable-diameter hole in this embodiment is an 8-shaped hole with a large-hole end and a small-hole end, and the large-hole end and the small-hole end respectively correspond to the aforementioned first hole area and second hole area. The bolt head of the connecting bolt 205 extends in from the large-hole end and then moves to the small-hole end for snap-fitting and fixing. In order to form the aforementioned inner cavity at the small-hole end, the end plate 301 can be fixed to the splicing end face of the pipe pile 1 in a spaced-apart manner, and the spacing height can accommodate the bolt head of the connecting bolt 205. Of course, an inner cavity can also be provided only at the small-hole end, and the opening of the inner cavity is reduced. In order to ensure sufficient tensile strength at the small-hole end, a strengthening structure can be provided at the peripheral edge of the hole at the small-hole end. In addition, in order to achieve the function of snap-fitting by rotation, the arrangement form of the end plate holes 302 on the end plate 301 needs to be consistent, that is, when viewed along the clockwise direction, the first hole area of all the end plate holes 302 needs to be always in the same direction as the second hole area.

[0070] As another preferred form of the embodiment of the present invention, as Figure 9 shown, the above reamer 4 includes a driving mechanism, and multiple groups of cross arms 405 and reaming end plates 410. Among them, in each group of cross arms 405 and reaming end plates 410, the reaming end plate 410 is connected to the driving mechanism through a cross arm 405. Driven by the driving mechanism, all the reaming end plates 410 synchronously expand and contract to form a gathering state and an expanding state. In the gathering state, the size after all the reaming end plates 410 are gathered can integrally extend into the enclosed space of the arc-shaped limiting plates of all the expanding blades 204 in the contracted state; while in the expanding state, the size after all the reaming end plates 410 are unfolded can make the arc-shaped limiting plates of all the expanding blades 204 support against the inner ring of the upper end plate 201 and the lower end plate 202 after expansion, so that all the expanding blades 204 reach the expanded state.

[0071] It should be noted that the specific form of the driving mechanism and its cooperation relationship with the cross arm 405 can be adjusted according to the actual situation. In this embodiment, a hydraulic linear driving device is adopted for the driving mechanism. The hydraulic linear driving device includes a hydraulic cylinder 401, a hydraulic piston rod 402, a first hydraulic pipe 403 and a second hydraulic pipe 404. The piston head of the hydraulic piston rod 402 is assembled in the hydraulic cylinder 401 and can slide freely. The piston head divides the hydraulic cylinder 401 into upper and lower regions. The upper hydraulic cylinder is connected to the first hydraulic pipe 403, and the lower hydraulic cylinder is connected to the second hydraulic pipe 404. The output rod connected to the piston head extends out of the hydraulic cylinder 401, and the output rod can be pushed to output power outward through the different input and output states of hydraulic oil in the first hydraulic pipe 403 and the second hydraulic pipe 404. The cross arm 405 is a scissor structure composed of two connecting rods connected by a pin shaft 407 in the middle. In this embodiment, there are a total of 4 cross arms 405 and 4 enlarged hole end plates 410. The inner sides of the 4 cross arms 405 are jointly assembled on the same group of fixed end blocks 408 and sliding end blocks 409, and the outer sides are respectively assembled on the 4 enlarged hole end plates 410. The hydraulic cylinder 401 is located at the center of the entire hole expander 4. The bottom of the hydraulic cylinder 401 is fixedly connected to the sliding end block 409. The output rod of the piston rod 402 passes through the guiding hole in the sliding end block 409 and is fixedly connected to the fixed end block 408. The output rod of the piston rod 402 can slide freely in the guiding hole. Thus, the relative distance between the fixed end block 408 and the sliding end block 409 can be changed through the piston rod 402, and further the hydraulic power can be converted into the radial driving force on the outer side of the cross arm 405. As Figure 10 shown, when the relative distance between the fixed end block 408 and the sliding end block 409 decreases, the cross arm 405 can push the enlarged hole end plate 410 to expand outward to reach the expanded state. As Figure 11 and Figure 12 shown, the gathered state and the expanded state of all the enlarged hole end plates 410 respectively correspond to the contracted state and the expanded state of all the diameter-expanding blades 204.

[0072] In addition, in order to prevent the output radial displacement from being too large, a limiter 406 is provided on the enlarged hole end plate 410. One end of the cross arm 405 needs to slide in the sliding groove of the limiter 406, and the two ends of the sliding groove constitute the two limit positions for the rotation of the cross arm 405. The specific dimensional parameters of the limiter 406 need to be reasonably optimized and designed according to the cooperation situation with the 4 diameter-expanding blades 204 in the diameter-expanding joint 2 to meet the function requirements.

[0073] As another preferred form of the embodiment of the present invention, as Figure 13As shown in the figure, the above-mentioned pile tip connecting collar 5 is composed of a first annular section 502, a second annular section 504, a top surface 501 that closes the top of the first annular section, and a stepped surface 503 that connects the two annular sections, and is integrally in a convex shape with an open bottom. The outer diameter of the first annular section 502 is the same as the inner diameter of the pipe pile 1 and can just be inserted into the pipe pile 1. The outer diameter of the second annular section 504 is the same as the outer diameter of the pipe pile 1 and does not protrude from the side wall of the pile body.

[0074] As another preferred form of the embodiment of the present invention, as Figure 14 shown, the pile tip 8 may include a cross pile tip plate 801 and a bottom seal 802. The cross pile tip plate 801 is welded to the bottom seal 802, and a pile tip chamfer 803 for facilitating insertion into the soil body is provided on the cross pile tip plate 801.

[0075] As Figure 15 shown, it is the assembled state of the pipe pile 1, the pipe pile joint 3, the pile tip connecting collar 5 and the pile tip 8. At this time, the pipe pile joint 3 at the end of the pipe pile 1 is supported on the stepped surface 503 of the pile tip connecting collar 5, the first annular section 502 extends into the inner cavity of the pipe pile 1, and the inner diameter of the second annular section 504 is the same as the diameter of the bottom seal 802 of the pile tip 8. The second annular section 504 is actually a flanging provided at the lower part of the stepped surface 503, and its height does not need to be very high, and it can hoop the pile tip 8 so that it will not tilt during the pile driving process. The second annular section 504 is buckled on the bottom seal 802 of the pile tip 8, but the buckling between the two is detachable, that is, the two will separate when receiving a separating force. Thus, the top surface 501, the first annular section 502 and the top surface of the pile tip 8 enclose a containing space. In the above-mentioned capsule type bottom expanding device 6 composed of the expandable capsule 601 and the capsule joint 602, the expandable capsule 601 is placed in this containing space, and the capsule joint 602 extends out of the pile tip connecting collar 5 through a through hole opened on the top surface 501. The capsule joint 602 can be used to connect a grouting machine 10 through a grouting pipe 7. The grouting liquid 603 is injected into the expandable capsule 601 by the grouting machine 10 through the grouting pipe 7 and expands the capsule 601 under the action of the grouting pressure, and pushes the pile tip 8 away from the second annular section 504, so as to create space for the expansion of the expandable capsule 601, and further form a pile end enlarged head by grouting and squeezing the soil around the expandable capsule 601.

[0076] As another preferred form of the embodiment of the present invention, since the capsule joint 602 is located at the bottom of the pile, there is a certain difficulty in docking it with the grouting pipe 7. Therefore, the end of the outlet end of the grouting pipe 7 uses a magnetic joint, which is self-locked under the action of the grouting pressure after being connected to the capsule joint 602, and can be freely pulled out when the grouting pressure disappears after the grouting is completed. At the same time, a centering device 9 is also designed to assist in keeping the bottom end of the grouting pipe 7 in the center of the pile body axis. As Figure 16As shown, the centering device 9 includes a sleeve 901 and a telescopic rod 902. The sleeve 901 is used to be fixedly sleeved on the pipeline extending into the pipe pile 1. Four telescopic rods 902 are vertically fixed on the sleeve 901 at equal circumferential angles, and the included angle between them is 90°. Of course, the telescopic rods 902 on the sleeve 901 can also be adjusted according to the actual situation, with at least three telescopic rods 902. The telescopic rods 902 can be synchronously telescoped according to the inner diameter of the pipe pile 1. The centering device 9 is fixed on the grouting pipe 7, so that the sleeve 901 and the internal grouting pipe 7 are always centered during the process of being lowered into the pipe pile 1. In order to ensure that the sleeve 901 is always centered, the lengths of all telescopic rods 902 should be adjusted to be equal to the difference between the inner radius of the pipe pile 1 and the outer radius of the sleeve 901.

[0077] In addition, in addition to the centering of the above-mentioned grouting pipe 7, as Figure 11 and Figure 12 shown, the centering device 9 can also be applied to two hydraulic pipes of the reamer 4. The two hydraulic pipes can adopt rigid pipes located on the central axis of the reamer 4. Thus, when the centering device 9 is sleeved on the first hydraulic pipe 403 and the second hydraulic pipe 404 and lowered, the reamer 4 can also be always centered in the pipe pile 1.

[0078] It should be noted that the specific materials of the components in the present invention are not limited, and are subject to meeting the requirements of the corresponding use scenarios for material strength and service life. For example, steel materials can be used.

[0079] Based on the above Figures 1 to 12 shown pipe pile jointing, bottom expanding and diameter expanding integrated device, in another embodiment of the present invention, a pipe pile jointing, bottom expanding and diameter expanding construction method using this integrated device is further provided, which successively includes the following steps:

[0080] S1. Determine the pile position coordinates according to the design drawings, and place the pile tip 8 on the ground at the coordinate point; install the capsule bottom expanding device 6 in the pile tip connecting ferrule 5, and keep the capsule joint 602 extending out of the pile tip connecting ferrule 5 through the through hole opened on the aforementioned top surface 501, and then buckle and fix the pile tip connecting ferrule 5 installed with the capsule bottom expanding device 6 on the pile tip 8. A pipe pile joint 3 is respectively fixed on the splicing end faces of all the pipe piles 1 to be connected.

[0081] S2. Vertically assemble the first section of the pipe pile 1 on the pile tip connecting ferrule 5, and insert the first annular section 502 above the pile tip connecting ferrule 5 into the pipe pile 1; then use the pile driving equipment to drive the first section of the pipe pile 1 into the soil layer, and only keep the top part of the pile exposed on the ground.

[0082] It should be noted that the pile driving process of the pipe pile 1 belongs to the prior art and can be realized by existing processes such as the static pressure method or the hammering method, and no specific description will be given here. During the pile driving process, in order to facilitate the connection of the subsequent expansion joint 2, the top of the pipe pile 1 is preferably controlled to be about 1 meter above the ground surface.

[0083] S3. Place an expansion joint 2 on the pipe pile joint 3 at the top of the pipe pile 1 exposed above the ground. Adjust the position so that the bolt heads of the connecting bolts 205 on the lower end plate 202 extend into the first hole area of the end plate holes 302 of the pipe pile joint 3 one by one. Then rotate the expansion joint 2 so that all the bolt heads of the connecting bolts 205 move from the first hole area to the second hole area, completing the connection of the expansion joint 2 to the lower pipe pile 1. Then place the pipe pile joint 3 at the bottom of another section of the pipe pile 1 on the upper end plate 201 of the expansion joint 2. Adjust the position so that the bolt heads of the connecting bolts 205 on the upper end plate 201 extend into the first hole area of the end plate holes 302 of the pipe pile joint 3 one by one. Then rotate the upper pipe pile 1 so that all the bolt heads of the connecting bolts 205 move from the first hole area to the second hole area, completing the connection of the expansion joint 2 to the upper pipe pile 1. Thus, the upper and lower two sections of the pipe pile 1 are both clamped on the upper and lower surfaces of the expansion joint 2 through the pipe pile joint 3, completing the connection and fixation of the upper and lower two sections of the pipe pile 1. Then continue to press the pile downwards so that the upper pipe pile 1 is driven into the soil layer and only the top part of the pile remains exposed above the ground surface.

[0084] S4. Continuously repeat step S3 until all the pipe piles 1 are driven into the soil layer.

[0085] S5. After all the pipe piles 1 are driven into the soil layer, take the hole expander 4 and initialize and adjust all the expansion end plates 410 therein to the gathered state. Then lower the hole expander 4 to the position of the first expansion joint 2, as shown in a in Figure 17 . Start the driving mechanism to synchronously extend all the expansion end plates 410 outwards to the expanded state. During the unfolding process of each expansion end plate 410, it can respectively push the corresponding expansion blades 204 outwards, so that all the expansion blades 204 in the first expansion joint 2 synchronously extend out of the pile body, thereby forming an expanded structure for improving the bearing capacity of the pile foundation. Then re-shrink all the expansion end plates 410 to the gathered state, lower them to the position of the next expansion joint 2, and start the driving mechanism again to synchronously extend all the expansion end plates 410 outwards to the expanded state, thereby converting the next expansion joint 2 into the expanded state as well. Continuously repeat this process until all the expansion joints 2 are converted into the expanded state, forming as shown in b in Figure 17 . Then keep all the expansion end plates 410 in the gathered state and take out the hole expander 4.

[0086] It should be noted that if the reamer 4 adopts the aforementioned rigid hydraulic pipe, the casing 901 of the centralizer 9 can be sleeved on the grouting pipe 7 connected to the grouting machine 10 in advance, and the length of the telescopic rod 902 can be adjusted according to the inner diameter of the pipe pile 1 so that the lengths of all the telescopic rods 902 are equal to the difference between the inner radius of the pipe pile 1 and the outer radius of the casing 901. This ensures that when the reamer 4 in the gathered state sinks into the next enlarged diameter joint 2, it can just enter the enclosed area surrounded by the four arc-shaped limit plates in the gathered state. Of course, since the four arc-shaped limit plates will reduce the diameter of some positions of the cross-section of the pile body cavity after the previous enlarged diameter joint 2 expands outwards, the four telescopic rods 902 of the centralizer 9 need to be staggered from the positions of the four arc-shaped limit plates during the process of the reamer 4 sinking into the next enlarged diameter joint 2.

[0087] S5. Sleeve the casing 901 of the centralizer 9 on the grouting pipe 7 connected to the grouting machine 10, and adjust the length of the telescopic rod 902 according to the inner diameter of the pipe pile 1 so that the lengths of all the telescopic rods 902 are equal to the difference between the inner radius of the pipe pile 1 and the outer radius of the casing 901; then gradually lower the grouting pipe 7 with the centralizer 9 along the inner cavity of the pile body. During the lowering process, the telescopic rods 902 of the centralizer 9 remain horizontal, so that the grouting pipe 7 can always be kept on the central axis of the pile body. When the grouting pipe 7 is lowered to the bottom of the pile, it is connected and locked with the bladder joint 602 through magnetic suction. At this time, start the grouting machine 10 to inject the grouting slurry into the expandable bladder 601 under pressure. The expandable bladder 601 expands under the action of the grouting pressure, thereby pushing the pile tip 8 away from the pile tip connecting collar 5 and continuing to extend out of the bottom of the pile to squeeze the surrounding soil. When the grouting volume or the grouting pressure reaches the design requirements, stop grouting, forming as shown in Figure 17 c in the figure. After the grouting is completed, pull out the centralizer 9 and the grouting pipe 7. After the cement slurry solidifies, a pile end enlarged head for improving the bearing capacity of the pile bottom is formed, forming as shown in Figure 17 d in the figure.

[0088] It should be noted that the above S1 - S5 describe the pile sinking construction process of one pile body. However, there may be multiple pile foundation sites that need to be constructed in a construction site. Therefore, the above process can be repeated for each site, and this will not be repeated here. The present invention can improve the side resistance and end resistance of the pile, can greatly improve the bearing capacity of the pile foundation, especially the uplift bearing capacity mainly based on the side friction of the pile can be significantly improved. Therefore, the pile length and the number of piles can be reduced, thereby reducing the project cost.

[0089] As another preferred form of the embodiment of the present invention, the maximum expanded diameter of the above expandable bladder 601 is 1.5 - 2 times the outer diameter of the pipe pile 1.

[0090] As another preferred form of the embodiment of the present invention, the grouting pressure of the grouting machine 10 is 0.5 - 2 MPa.

[0091] As another preferred form of the embodiment of the present invention, the grouting liquid 603 is cement slurry or fine aggregate concrete, and dual control of the grouting volume and grouting pressure is adopted. Grouting can be stopped when any one of them meets the design requirements.

[0092] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An integrated device for expanding the bottom and diameter of a pipe pile joint, characterized in that, It includes a pipe pile (1), an expanding diameter joint (2), a pipe pile joint (3), an under-reamer (4), a pile tip connecting collar (5), a bladder-type under-reaming device (6) and a pile tip (8); Multiple sections of pipe piles (1) are sequentially spliced vertically to form a pile body; on the splicing end faces of any two adjacent pipe piles (1), a pipe pile joint (3) is respectively fixed, and the two pipe pile joints (3) are clamped and fixed by the expanding diameter joint (2), so that two adjacent pipe piles (1) form a reliable connection; the expanding diameter joint (2) is provided with a variable diameter mechanism capable of expanding and contracting radially along the cross-section of the pile body, and the variable diameter mechanism has a contracted state completely retracted into the pile body and an expanded state extending out of the pile body; The under-reamer (4) is used to apply a radial driving force along the cross-section of the pile body to the variable diameter mechanism, so as to convert the expandable diameter mechanism from the contracted state to the expanded state; The lowermost section of pipe pile (1) in the pile body is installed on the pile tip (8) through the pile tip connecting collar (5); the bladder-type under-reaming device (6) is installed above the pile tip (8), and it is provided with a grouting port; The grouting port is used to connect an external grouting machine (10) through a grouting pipe (7), so as to press the slurry into the expandable bladder of the bladder-type under-reaming device (6), so that the expandable bladder grouts and expands to push the pile tip (8) away from the pile tip connecting collar (5) and further squeezes and expands the surrounding soil at the pile bottom by the bladder to form a pile end enlarged head; The expanding diameter joint (2) includes an upper end plate (201), a lower end plate (202), connecting rib plates (203), expanding diameter blades (204) and connecting bolts (205); the upper end plate (201) and the lower end plate (202) are arranged in parallel at intervals, and a connecting structure capable of bearing the load in the direction perpendicular to the end plate is formed by clamping and fixing a number of connecting rib plates (203) therebetween; the expanding diameter blades (204) are assembled corresponding to the connecting rib plates (203) one by one. Each expanding diameter blade (204) includes a fan-shaped ring plate and an arc-shaped limiting plate, and a through-channel is opened on the fan-shaped ring plate. The fan-shaped ring plate is installed between the upper end plate (201) and the lower end plate (202), and the fan-shaped ring plate is sleeved outside the connecting rib plate (203) through the through-channel to form a sliding pair restricting the radial movement of the fan-shaped ring plate. The size of the arc-shaped limiting plate is larger than the gap between the upper end plate (201) and the lower end plate (202), and when the arc-shaped limiting plate moves outwards to the limit position, it can restrict its further outward movement; on the outer-facing plate surfaces of the upper end plate (201) and the lower end plate (202), connecting parts for connecting the pipe pile joint (3) are respectively provided; The pile tip connecting collar (5) is composed of a first annular section (502), a second annular section (504), a top surface (501) that closes the top of the first annular section, and a stepped surface (503) that connects the two annular sections, and is in an overall convex shape with an open bottom; wherein the outer diameter of the first annular section (502) is the same as the inner diameter of the pipe pile (1), and the outer diameter of the second annular section (504) is the same as the outer diameter of the pipe pile (1); in the assembled state, the pipe pile joint (3) at the end of the pipe pile (1) is supported on the stepped surface (503), the first annular section (502) extends into the inner cavity of the pipe pile (1), the second annular section (504) is detachably buckled on the pile tip (8), and the top surface (501), the first annular section (502), and the top surface of the pile tip (8) enclose a containing space; the bladder type bottom expanding device (6) includes an expandable bladder (601) and a bladder joint (602); the expandable bladder (601) is placed in the containing space; the bladder joint (602) extends out of the pile tip connecting collar (5) through a through hole opened on the top surface (501) for injecting grouting liquid (603) into the expandable bladder (601).

2. The pipe pile splicing, bottom expanding and diameter expanding integrated device according to claim 1, wherein, The pipe pile joint (3) includes an end plate (301) and end plate holes (302), and the end plate (301) is fixed on the splicing end surface of the pipe pile (1); the end plate holes (302) are evenly arranged along the circumference of the end plate, and the number and positions are the same as the number of connecting parts on the diameter expanding joint (2), and the connecting parts can be fixedly fitted into the end plate holes (302).

3. The pipe pile joint pile bottom expanding and diameter expanding integrated device according to claim 2, characterized in that, The connecting parts on the upper end plate (201) and the lower end plate (202) are connecting bolts (205), the threaded sections of the connecting bolts (205) are fixed on the corresponding end plates, and the bolt heads are spaced from the end plate surfaces; the end plate holes (302) on the end plate (301) are variable diameter holes, and the variable diameter holes have a first hole area and a second hole area that are connected. The hole size of the first hole area can allow the bolt heads to extend in, and the bolt heads can move from the first hole area to the second hole area, but the hole size of the second hole area cannot directly allow the bolt heads to break away from the second hole area.

4. The pipe pile splicing, bottom expanding and diameter expanding integrated device according to claim 3, characterized in that, The hole expander (4) includes a driving mechanism, multiple groups of cross arms (405), and hole expanding end plates (410); in each group of cross arms (405) and hole expanding end plates (410), the hole expanding end plates (410) are connected to the driving mechanism through the cross arms (405); under the drive of the driving mechanism, all the hole expanding end plates (410) synchronously expand and contract to form a gathering state and an expanding state; in the gathering state, the size of all the hole expanding end plates (410) after gathering can integrally extend into the arc-shaped limiting plate enclosing space of all the diameter expanding blades (204) in the contracted state; In the expanding state, the size of all the hole expanding end plates (410) after expansion can make the arc-shaped limiting plates of all the diameter expanding blades (204) support against the inner rings of the upper end plate (201) and the lower end plate (202) after outward expansion.

5. The pipe pile splicing and bottom and diameter expanding integrated device according to claim 4, characterized in that, The end of the outlet end of the grouting pipe (7) uses a magnetic joint that can be connected and locked self-locking with the bladder joint (602).

6. The pipe pile splicing, bottom expanding and diameter expanding integrated device according to claim 5, wherein, It further includes a centering device (9) for keeping the pipeline extending into the pipe pile (1) centered all the time; the centering device (9) includes a sleeve (901) and at least three telescopic rods (902), the sleeve (901) is used for sleeving and fixing on the pipeline extending into the pipe pile (1), and all the telescopic rods (902) are vertically fixed on the sleeve (901) at equal circumferential angles, and the telescopic rods (902) can synchronously expand and contract according to the inner diameter size of the pipe pile (1), so that the sleeve (901) and the pipeline passing through the inside thereof are always centered during the up-and-down movement in the pipe pile (1).

7. A construction method for expanding the bottom and diameter of a pipe pile joint using the integrated device described in claim 6, characterized in that, It includes: S1. Determine the pile position coordinates according to the design drawing, and place the pile tip (8) on the ground at the coordinate point; install the capsule-shaped under-reaming device (6) in the pile tip connecting collar (5), keep the capsule joint (602) extending out of the pile tip connecting collar (5) through the through hole opened on the top surface (501), and then buckle and fix the pile tip connecting collar (5) installed with the capsule-shaped under-reaming device (6) on the pile tip (8); respectively fix a pipe pile joint (3) on the splicing end faces between all the pipe piles (1) to be connected with each other; S2. Vertically assemble the first pipe pile (1) on the pile tip connecting collar (5), and insert the first annular section (502) above the pile tip connecting collar (5) into the pipe pile (1); then use the pile driving equipment to drive the first pipe pile (1) into the soil layer, and only keep the pile top part exposed on the ground; S3. Place an expanding joint (2) on the pipe pile joint (3) at the pile top of the pipe pile (1) exposed on the ground, adjust the position to make the bolt heads of the connecting bolts (205) on the lower end plate (202) extend into the first hole area of the end plate holes (302) of the pipe pile joint (3) one by one, and then rotate the expanding joint (2) to make all the bolt heads of the connecting bolts (205) move from the first hole area to the second hole area to complete the connection between the expanding joint (2) and the lower pipe pile (1); then place another pipe pile (1) on the upper end plate (201) of the expanding joint (2), adjust the position to make the bolt heads of the connecting bolts (205) on the upper end plate (201) extend into the first hole area of the end plate holes (302) of the pipe pile joint (3) one by one, and then rotate the upper pipe pile (1) to make all the bolt heads of the connecting bolts (205) move from the first hole area to the second hole area to complete the connection between the expanding joint (2) and the upper pipe pile (1); after completing the connection and fixation of the upper and lower two pipe piles (1), continue to press the pile downwards so that the upper pipe pile (1) is driven into the soil layer and only keep the pile top part exposed on the ground; S4. Continuously repeat step S3 until all the pipe piles (1) are driven into the soil layer; S5. After all the pipe piles (1) are driven into the soil layer, lower the expander (4) with all the reaming end plates (410) in the gathered state to the position of the first diameter-expanding joint (2). Start the driving mechanism to synchronously extend all the reaming end plates (410) outward to the expanded state. During the unfolding process, each reaming end plate (410) can respectively push the corresponding diameter-expanding blades (204) outward, so that all the diameter-expanding blades (204) in the first diameter-expanding joint (2) synchronously extend out of the pile body to form a diameter-expanding structure for improving the bearing capacity of the pile foundation. Then, shrink all the reaming end plates (410) back to the gathered state again, lower them to the position of the next diameter-expanding joint (2) and change it to the diameter-expanding state. Keep repeating until all the diameter-expanding joints (2) are changed to the diameter-expanding state, and then take out the expander (4). S6. Put the sleeve (901) of the centering device (9) on the grouting pipe (7) connected to the grouting machine (10), and adjust the length of the telescopic rod (902) according to the inner diameter of the pipe pile (1) so that the length of all the telescopic rods (902) is equal to the difference between the inner radius of the pipe pile (1) and the outer radius of the sleeve (901). Then lower the grouting pipe (7) with the centering device (9) to the bottom of the pile and connect it to the bladder joint (602). Start the grouting machine (10) to pressurize and inject the grouting slurry into the expandable bladder (601). Under the action of the grouting pressure, the expandable bladder (601) expands to push the pile tip (8) out of the pile tip connecting collar (5), and continues to extend out of the bottom of the pile to squeeze and expand the surrounding soil. After the grouting is completed, pull out the centering device (9) and the grouting pipe (7). After the cement slurry solidifies, a pile tip enlargement for improving the bearing capacity of the pile bottom is formed.

8. The pipe pile splicing and bottom and diameter expanding construction method according to claim 7, characterized in that, The maximum expanded diameter of the expandable bladder (601) is 1.5 - 2 times the outer diameter of the pipe pile (1); the grouting pressure of the grouting machine (10) is 0.5 - 2 MPa; the grouting liquid (603) uses cement slurry or fine aggregate concrete, and is controlled by both the grouting volume and the grouting pressure. When any one reaches the design requirement, the grouting can be stopped.

Images