Prestressed concrete special-shaped hollow square pile

Abstract

The utility model discloses a prestressed concrete special-shaped hollow square pile which comprises a bottom pile and a plurality of connecting piles. A plurality of staggered sliding grooves are formed in the outer side wall of the pile body, and hook blocks are inserted into the sliding grooves in a sliding mode. A plurality of inserting rods and filling rods are inserted in the pile body in a staggered mode, the hook blocks are extruded to protrude out of the side wall of the pile body, and side resistance is increased. The upper end of the bottom pile is provided with a slot, and the upper end of the connecting pile is provided with an insertion hole into which the insertion rod and the filling rod are inserted. And a connecting ring is in threaded connection with the joint. The section of the bottom pile is square, and arc-shaped chamfers are arranged on the sides. The upper end of the hook block is fixedly connected with a stopper for limiting. The side resistance of the pile body is improved, the anti-seismic property is improved, and the problem that an existing prestressed concrete pile easily shakes or is separated from a foundation pit during vibration is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of prefabricated piles, in particular to prestressed concrete special-shaped hollow square piles. Background Art

[0002] Prestressed concrete piles are a special type of concrete piles, which apply pre-designed prestressing force during the construction process, that is, a certain tensile stress or compressive stress is applied to the pile body through a method determined by pre-calculation and design to improve the bearing capacity and seismic performance of the pile. This prestressing force is usually achieved through prestressed steel bars or prestressed steel bundles to improve the bearing capacity and seismic performance of the pile, such as the post-grouting prestressed hollow square pile and its manufacturing method in CN114197452B. Prestressed concrete piles are usually used in engineering projects that require greater bearing capacity and higher seismic performance, such as bridges, high-rise buildings, infrastructure and other fields.

[0003] However, the outer wall of the existing prestressed concrete piles is mostly a flat structure (column-like structure). Flat prestressed concrete piles are easy to install, but the side resistance of the concrete piles with flat outer walls is low, resulting in poor seismic performance. When vibration occurs, it is easy to shake in the foundation pit or even fall out of the foundation pit. In order to solve the above-mentioned problems, a prestressed concrete special-shaped hollow square pile is provided. Utility Model Content

[0004] The purpose of the utility model is to provide prestressed concrete special-shaped hollow square piles to solve the problem proposed in the above background technology that the existing prestressed concrete piles have low lateral resistance, resulting in poor seismic performance and are prone to shaking in the foundation pit or even falling out of the foundation pit when vibration occurs.

[0005] To achieve the above purpose, the utility model provides the following technical solution: prestressed concrete special-shaped hollow square pile, including a pile body,

[0006] The cracking bending moment of the pile is: Mcr = (δpc + γftk) W0 × 10-6;

[0007] Mcr is the cracking bending moment of the pile body; δpc is the effective precompression stress of the pile body concrete; γ is the plastic influence coefficient of the section resistance moment considering the process influence and the concrete component; ftk is the standard value of the axial tensile strength of concrete; W0 is the conversion value of the elastic resistance moment of the tensile edge;

[0008] The design value of the bending bearing capacity of the pile cross section Mz is:

[0009] Mz=∑δpi•Api(hi-x / 2)×10-6; when ∑δpi•Api≤α1fcBh'f;

[0010] Mz=∑δpi•Api(hi-xt / 2)×10-6;

[0011] Mz is the design value of the bending bearing capacity of the positive section;

[0012] α1 is the coefficient, when C80, it is 0.98;

[0013] fc is the design value of concrete axial compressive strength;

[0014] B is the outer length of the hollow square pile;

[0015] h'f is the flange height of the compression zone of the I-shaped section;

[0016] δpi is the calculated stress value of the i-th row of prestressed steel bars;

[0017] Api is the cross-sectional area of ​​the i-th row of prestressed steel bars;

[0018] hi is the distance between the i-th row of prestressed steel bars and the outer edge of the concrete compression zone;

[0019] x is the height of the concrete compression zone of the equivalent rectangular stress diagram;

[0020] xt is the distance from the centroid of the T-shaped compression zone formed after the height of the concrete compression zone exceeds the flange height to the outer edge of the concrete compression zone;

[0021] b is the web width of the I-section.

[0022] In another embodiment of the present application, a plurality of slide grooves are opened on the outer wall of the pile body, and the slot openings of the slide grooves face upward, and a hook block is slidably inserted in the slide grooves. A plurality of insertion rods and filling rods are sequentially inserted into the interior of the pile body, and the insertion rods and filling rods located in the pile body are staggered. The insertion rods and filling rods are inserted into the pile body to squeeze one end of the hook block, and the other end of the hook block is squeezed out from the slot opening of the slide groove. The hook block protruding from the side wall of the pile body increases the lateral resistance of the pile body.

[0023] As a preferred technical solution of the utility model, the pile body includes a bottom pile and multiple connecting piles, the multiple connecting piles are connected to each other in a straight line, and the bottom pile is fixedly connected to the lower end of the lowest connecting pile, a slot is provided at the upper end of the bottom pile, and a socket is provided at the upper end of the connecting pile, multiple plug rods are respectively inserted into the slots and the sockets, and the filling rod is also inserted into the socket, and the filling rod is located below the plug rod in the socket.

[0024] As a preferred technical solution of the utility model, the connection between the connecting pile and the bottom pile and the connection between adjacent connecting piles are both threadedly connected with connecting rings.

[0025] As a preferred technical solution of the utility model, the cross-section of the bottom pile is set to be square, and the sides of the bottom pile are provided with arc chamfers.

[0026] As a preferred technical solution of the utility model, a plurality of slide grooves are staggered.

[0027] As a preferred technical solution of the utility model, a stopper for limiting the hook block is fixedly connected to the upper end of the hook block.

[0028] As a preferred technical solution of the utility model, the connecting ring includes two clamping rings, and the two clamping rings are spliced ​​and clamped to each other on both sides of the connection between the connecting pile and the bottom pile or the connection between adjacent connecting piles.

[0029] As a preferred technical solution of the utility model, the slot of the slide groove faces downward, and a clamping block is slidably installed in the slide groove.

[0030] As a preferred technical solution of the utility model, a groove is provided at the upper end of the clamping block to increase the bonding effect with concrete.

[0031] Compared with the prior art, the beneficial effects of the utility model are:

[0032] The utility model connects a connecting ring to fix a bottom pile and a plurality of connecting piles to form a pile body, and the pile body is inserted into a foundation pit, and concrete slurry is poured into the gap between the pile body and the foundation pit. After the slurry is filled, a plurality of insertion rods and filling rods are sequentially inserted into the insertion hole until the insertion hole and the slot are filled. During the insertion process of the insertion rod, the insertion rod contacts the hook block, and the hook block is squeezed out from the notch of the slide groove. The extended hook block is inserted into the concrete slurry, and the extended hook block increases the lateral resistance, thereby solving the problem that the lateral resistance of the existing prestressed concrete piles is low, resulting in poor seismic performance, and the piles are easy to shake in the foundation pit or even fall out of the foundation pit when vibration occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the local structure of a concrete pile according to the first embodiment of the utility model;

[0034] Figure 2 This is a cross-sectional view of a connecting pile according to Embodiment 1 of the present utility model;

[0035] Figure 3 For the first embodiment of the utility model Figure 2 Enlarged view of point A in the middle;

[0036] Figure 4 This is a cross-sectional view of the bottom pile of the first embodiment of the utility model;

[0037] Figure 5 This is an exploded view of the connecting ring of the first embodiment of the utility model;

[0038] Figure 6This is a top view of the concrete pile installation of the first embodiment of the utility model;

[0039] Figure 7 This is a schematic diagram of the local structure of a concrete pile according to Embodiment 2 of the present utility model;

[0040] Figure 8 This is a cross-sectional view of a connecting pile according to Embodiment 2 of the present utility model;

[0041] Fig. 9 For the second embodiment of the utility model Figure 8 Enlarged view of point B in the middle;

[0042] Fig.10 This is a cross-sectional view of the bottom pile of the second embodiment of the utility model.

[0043] Fig.11 This is a schematic diagram of the structure of the third embodiment of the present invention.

[0044] Fig.12 This is a schematic structural diagram of the fourth embodiment of the present utility model.

[0045] Fig.13 It is a schematic diagram of a connecting piece of Embodiment 3 of the present utility model.

[0046] Fig.14 It is a schematic diagram of the anchor bars of the end plate of the pull-out pile in the third embodiment of the utility model.

[0047] Fig.15 It is a schematic diagram of the core filling connection between the pile top and the cap in the third embodiment of the present utility model.

[0048] Fig.16 It is a front view of the conical concrete pile tip of the third embodiment of the utility model.

[0049] In the figure: 1, bottom pile; 2, connecting pile; 3, connecting ring; 4, hook block; 41, stopper; 5, insertion rod; 51, filling rod; 6, clamping block; 61, groove. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0051] For example, see Figure 1-6 , this embodiment provides a prestressed concrete special-shaped hollow square pile, including a pile body of a concrete pile.

[0052] Specifically, the cross-section of the pile body is set to be square. Compared with the existing cylindrical pile body, the square pile is easier to adjust and align during construction, and the position and direction of the pile can be more accurately controlled, thereby improving construction efficiency.

[0053] The pile body is provided with a cylindrical through hole. The opening of the through hole reduces the deadweight of the pile body and reduces the vertical load of the pile body on the foundation, which is conducive to reducing the settlement of the foundation. The through hole can also reduce the amount of materials required and save costs, especially for deep foundations, which can significantly reduce material consumption. Grouting can be carried out in the through hole to ensure the overall stability and bearing capacity of the pile. The through hole can also be used to install monitoring equipment, such as strain gauges, displacement gauges, etc., to monitor the deformation and bearing performance of the pile in real time.

[0054] like Figure 6 As shown, since the foundation pits K are mostly cylindrical, arc chamfers are provided at the edges of the pile bodies to facilitate the insertion of the pile bodies into the foundation pits K and reduce the friction between the side walls of the pile bodies and the inner walls of the foundation pits K.

[0055] like Figure 1 As shown, the pile body includes a bottom pile 1 and a connecting pile 2, wherein the connecting pile 2 is provided in plurality, the plurality of connecting piles 2 are arranged up and down in a straight line and are connected to each other, and the lowest connecting pile 2 is fixedly connected to the upper end of the bottom pile 1.

[0056] like Figure 2 As shown, the upper and lower ends of the outer wall of the connecting pile 2 are provided with slots, such as Figure 4 As shown, a slot is also provided at the upper end of the outer wall of the bottom pile 1 , and a connecting ring 3 is threadedly connected in the slots between the bottom pile 1 and the lowest connecting pile 2 and in the slots between adjacent connecting piles 2 .

[0057] like Figure 5 As shown, the connecting ring 3 includes two snap rings, which can be spliced ​​into an annular structure. The two snap rings are engaged in two adjacent slots, and the snap rings are fixed in the slots by threaded connection, so that two adjacent connecting piles 2 or the lowest connecting pile 2 is fixedly connected to the bottom pile 1, so that the bottom pile 1 and multiple connecting piles 2 form the entire pile body.

[0058] During installation, first drill a foundation pit K on the ground, insert the pile body into the foundation pit K, inject concrete slurry into the gap between the foundation pit K and the pile body, and after the concrete solidifies, the installation of the pile body is completed.

[0059] The flat pile body has low lateral resistance, that is, the contact area with concrete is small, which reduces the lateral friction resistance of the pile and the lateral bearing capacity of the pile. When encountering vibration, the pile body is easy to shake in the foundation pit K, and even detach from the foundation pit K. Therefore, in order to increase the lateral resistance of the pile body, such as Figure 1 As shown, a hook block 4 is provided on the side wall of the pile body.

[0060] Specifically, Figure 2 , Figure 3 and Figure 4 As shown, the outer walls of the bottom pile 1 and the connecting pile 2 are provided with a slide groove, and the slide groove is provided in multiple numbers, and the hook block 4 is slidably inserted in the slide groove. The upper end of the bottom pile 1 is provided with four slots, and the connecting pile 2 is provided with four insertion holes, and the insertion holes of the connecting pile 2 are aligned with the slots of the bottom pile 1 and are connected to each other.

[0061] like Figure 2 As shown, an insert rod 5 and a filling rod 51 are inserted into the insertion hole of the connecting pile 2, and an insert rod 5 is also inserted into the slot of the bottom pile 1. When in use, multiple insert rods 5 and filling rods 51 are inserted in sequence from the insertion hole of the top connecting pile 2, so that the first inserted insert rod 5 is slidably inserted into the slot of the bottom pile 1. After the interior of the bottom pile 1 and all the connecting piles 2 are filled, the installation is completed.

[0062] Before installation, one end of the hook block 4 installed on the bottom pile 1 is inserted into the slot, and one end of the hook block 4 installed on the connecting pile 2 is inserted into the insertion hole. The lower ends of the insertion rod 5 and the filling rod 51 are set as inclined surfaces. When the insertion rod 5 and the filling rod 51 are plugged in, the inclined surface contacts the hook block 4, and a thrust is applied to one end of the hook block 4, so that the other end of the hook block 4 extends out from the notch of the slide groove. The extended hook block 4 increases the contact area between the pile body and the concrete, enhances the lateral resistance of the pile body, and thereby increases the seismic effect of the pile body.

[0063] Since one end of the hook block 4 is completely inserted into the slot or the jack, blocking the slot or the jack will affect the insertion of the insertion rod 5 and the filling rod 51. Figure 3 As shown, a stopper 41 is fixedly connected to the upper end of the hook block 4, and the stopper 41 limits the hook block 4 to prevent one end of the hook block 4 from completely sliding into the slot or the jack and blocking the slot or the jack.

[0064] like Figure 1 As shown, the slide grooves on the side walls of the pile body are staggered, and the hook blocks 4 extending therefrom are staggered. The staggered hook blocks 4 can further increase the lateral resistance of the pile body and increase the installation stability of the pile body.

[0065] For example 2, please refer to Figure 7-10 , which is different from the first embodiment in that:

[0066] The slot opening of the slide groove faces upward, and a clamping block 6 is slidably inserted into the slot opening of the slide groove.

[0067] Before installation, the interaction force between the block 6 and the inner wall of the slide groove forms a damping force to fix the block 6, preventing the block 6 from sliding out from the notch of the slide groove. At this time, one end of the block 6 is flush with the outer wall of the pile body, making the surface of the pile body flat, making it convenient for the pile body to be inserted into the foundation pit K.

[0068] After the concrete is poured in the foundation pit K, when the insertion rod 5 and the filling rod 51 are inserted into the slot of the bottom pile 1 and the insertion hole of the connecting pile 2, the inclined surfaces of the insertion rod 5 and the filling rod 51 contact the block 6, and the block 6 slides out from the notch of the slide groove under the thrust. The extended block 6 increases the contact area between the pile body and the concrete, enhances the lateral resistance of the pile body, and thereby increases the seismic effect of the pile body.

[0069] The pile body will vibrate when inserted into the foundation pit K. Compared with the hook block 4 extending out of the pile body due to the vibration and being easily stuck on the inner wall of the foundation pit K, after the clamping block 6 extends out from the outer wall of the pile body due to the vibration, the slot opening is downward, and after the side wall of the foundation pit K contacts the clamping block 6, it can drive the clamping block 6 to retract into the slot, thereby preventing the pile body from getting stuck during installation.

[0070] like Figure 8 As shown, the upper end of the block 6 extending obliquely downward is an inclined surface. In order to further increase the bonding effect between the pile body and the concrete and increase the lateral resistance of the pile body, a groove 61 is provided at the upper end of the block 6.

[0071] After one end of the block 6 extends out from the slide groove, the concrete slurry will flow into the groove 61. After the concrete solidifies, the bonding effect between the pile body and the concrete can be increased, thereby increasing the lateral resistance of the pile body. Example

[0072] The cracking bending moment of the pile is: M cr =(δ pc +γf tk )W0×10 -6 ;

[0073] M cr is the cracking bending moment of the pile body; δ pc The effective precompression stress of the pile concrete; γ is the plasticity coefficient of the section resistance moment of the concrete component considering the influence of the process; f tk is the standard value of concrete axial tensile strength; W0 is the converted value of elastic resistance moment of tensile edge;

[0074] Design value of the bending bearing capacity of the pile body's normal section M z for:

[0075] M z =∑δ pi ·A pi (h i -x / 2)×10 -6 ; When ∑δ pi ·A pi ≤α1f c Bh ＇ f ;

[0076] M z =∑δ pi·A pi (h i -x t / 2)×10 -6 ;x t = (0.5 (Bb) h f 2 +0.5bx 2 ) / ((Bb)h f +bx); when ∑δ pi ·A pi >α1f c Bh ＇ f ;

[0077] M z is the design value of the bending bearing capacity of the positive section;

[0078] α1 is the coefficient, when C80, it is 0.98;

[0079] f c is the design value of concrete axial compressive strength;

[0080] B is the outer length of the hollow square pile;

[0081] h ＇ f is the flange height of the compression zone of the I-shaped section;

[0082] δ pi is the calculated stress value of the i-th row of prestressed steel bars;

[0083] A pi is the cross-sectional area of ​​the i-th row of prestressed steel bars;

[0084] h i is the distance between the i-th row of prestressed steel bars and the outer edge of the concrete compression zone;

[0085] x is the height of the concrete compression zone of the equivalent rectangular stress diagram;

[0086] x t It is the distance from the centroid of the T-shaped compression zone formed after the height of the concrete compression zone exceeds the flange height to the outer edge of the concrete compression zone;

[0087] b is the web width of the I-section.

[0088] When x<2a', the design value of the bending bearing capacity of the positive section should be calculated as follows:

[0089] M=f py ∑A pi (h i -a')×10 -6 ;

[0090] Where: f py It is the design value of tensile strength of prestressed steel bars.

[0091] The bending bearing capacity test value of the pile body cross section should be calculated according to the following formula: M u =1.35M

[0092] Calculation of design value of vertical compressive bearing capacity of pile structure:

[0093] When the effect of hollow square pile buckling is not considered, the design value of the vertical compressive bearing capacity of the pile structure should be calculated as follows: Rp=Ψ c f c A / 1000;

[0094] In the formula, R p ——design value of the vertical compressive bearing capacity of the pile; f c is the design value of concrete axial compressive strength; c is the pile construction coefficient, which is taken as 0.65 in this atlas; A is the cross-sectional area of ​​the hollow square pile.

[0095] For hollow square pile foundations where the pile body passes through liquefied soil, silt, silty soil or soft soil layers with undrained shear strength less than 10kPa, the buckling effect of the hollow square pile should be considered. When considering the buckling effect of the hollow square pile, the design value of the vertical compressive bearing capacity of the pile body structure should be calculated as follows: Rp = ΦΨ c f c A / 1000;

[0096] Where: Φ is the compressive stability coefficient of hollow square piles, according to the Technical Specifications for Building Pile Foundations JGJ94

[0097] Determined execution.

[0098] The design value of the shear bearing capacity of hollow square piles should be calculated according to the following formula:

[0099] V0=(0.7f t bh0+1.0f yv h0sinθ+ 0.05δ pc A0) / 1000;

[0100] Where: V0 is the design value of the shear force of a single hollow square pile; f t is the design value of concrete axial tensile strength; δ pc is the effective precompression stress of the pile concrete; A0 is the converted cross-sectional area of ​​the hollow square pile; b is the web width of the hollow square pile converted into an I-shaped cross-section with equal area and equal moment of inertia; h0 is the effective height of the cross-section; f yv is the design value of stirrup strength; A svis the total cross-sectional area of ​​each limb of the stirrups configured in the same section; s is the stirrup spacing along the length direction of the hollow square pile; θ is the angle between the stirrups and the longitudinal axis of the hollow square pile.

[0101] The shear bearing capacity test value of the hollow square pile can be calculated as follows: V u =1.40V0;

[0102] When the hollow square pile is under tension, it should be verified according to the first-level crack control level requirements and the following formula: N pc ≤(δ pc A0) / 1000;

[0103] The tensile bearing capacity test value of the hollow square pile body structure is based on the tensile strength of the hollow square pile in the general environment or design

[0104] Generally, it is required that no cracks appear when calculated. The inspection value is calculated according to the following formula: Nu<(σ ρc +f tk )A0 / 1000;

[0105] Where: M is the test value of the pull-out bearing capacity of a single hollow square pile; σ ρc is the effective precompression stress of pile concrete; f tk The standard value of the axial tensile strength of the pile concrete; A0 is the converted cross-sectional area of ​​the hollow square pile.

[0106] The mass per unit length of hollow square pile should be calculated as follows: m = 1000ρ c A c / 9.8;

[0107] Where: m is the mass per unit length of the hollow square pile; ρ c is the concrete density, take 2.5×10 -5 N / mm 3 ; A c is the effective cross-sectional area of ​​the pile body.

[0108] like Fig.13 and Fig.14 As shown in the figure, the operation process of pile connection is: screw the circlip nut into the short sleeve at the lower end of the upper pile → screw the conical plug into the long sleeve at the top of the lower pile → pile termination. Clean the contact surface → apply structural adhesive to the contact surface → align the mechanical connection joints of the upper and lower piles → lower the conical plug of the upper pile into the long sleeve of the lower pile → weld the end plate → clean the weld surface → cool the weld. The quality grade of the weld between the pile sleeve and the end plate is Grade III.

[0109] like Fig.15As shown in the figure, a support plate should be set in the top of the pile and a steel skeleton should be placed in it. The core-filled concrete below the design elevation should be poured. Its strength grade should be one level higher than the pedestal or foundation and not lower than C30 slightly expansive concrete. After the core-filled concrete reaches 70% of the design strength, the excess part above the design elevation of the pile top can be chiseled off. Before pouring the core-filled concrete, the slurry layer on the inner wall of the pile should be cleaned first. According to the design requirements, measures such as coating the inner wall with concrete interface agent can be adopted to improve the integrity of the core-filled concrete and the concrete of the hollow square pile body.

[0110] like Fig.16 As shown, scope of application: This type of pile tip is mainly used in friction piles with thick soft soil and no hard layer in the middle soil layer, as well as thick sand layers. Unless otherwise specified, all welds at the pile tip are fillet welds, and the weld quality should not be lower than Grade 3. The pile tip material is Q235B, and the welding rod is E43. The concrete strength grade of the pile tip: C40 for hammer piles and C30 for static pressure piles. All welds at the pile tip must not have welding defects, and must be corrected and cleaned after welding.

[0111] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Prestressed concrete special-shaped hollow square pile, including a pile body, characterized in that: The outer wall of the pile body is provided with a plurality of slide grooves, and the slot openings of the slide grooves face upwards; a hook block (4) is slidably inserted into the slide groove; a plurality of insertion rods (5) and filling rods (51) are sequentially inserted into the interior of the pile body; and the insertion rods (5) and filling rods (51) located in the pile body are arranged in a staggered manner; The insertion rod (5) and the filling rod (51) are inserted into the pile body to squeeze one end of the hook block (4), and the other end of the hook block (4) is squeezed out from the notch of the slide groove, so that the hook block (4) protrudes from the side wall of the pile body to increase the lateral resistance of the pile body; The pile body comprises a bottom pile (1) and a plurality of connecting piles (2), the plurality of connecting piles (2) are connected to each other in a straight line, and the bottom pile (1) is fixedly connected to the lower end of the lowest connecting pile (2), a slot is provided at the upper end of the bottom pile (1), a plug hole is provided at the upper end of the connecting pile (2), a plurality of plug rods (5) are respectively plugged into the slots and the plug hole, the filling rod (51) is also plugged into the plug hole, and the filling rod (51) is located below the plug rod (5) in the plug hole; The connection between the connecting pile (2) and the bottom pile (1) and the connection between adjacent connecting piles (2) are both threadedly connected with a connecting ring (3); The cross section of the bottom pile (1) is arranged to be square, and the sides of the bottom pile (1) are arranged to be arc-shaped chamfered; A plurality of the slide grooves are arranged in a staggered manner; A stopper (41) for limiting the hook block (4) is fixedly connected to the upper end of the hook block (4).

2. The prestressed concrete special-shaped hollow square pile according to claim 1, characterized in that: The connecting ring (3) comprises two clamping rings, and the two clamping rings are spliced ​​and clamped to each other on both sides of the connection between the connecting pile (2) and the bottom pile (1) or the connection between adjacent connecting piles (2).

3. The prestressed concrete special-shaped hollow square pile according to claim 1, characterized in that: The slot opening of the slide groove faces downward, and a clamping block (6) is slidably installed in the slide groove.

4. The prestressed concrete special-shaped hollow square pile according to claim 3 is characterized in that: The upper end of the clamping block (6) is provided with a groove (61) for increasing the bonding effect with concrete.

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