Steel pipe pile and bearing platform anchoring structure

Abstract

The utility model discloses a steel pipe pile and bearing platform anchoring structure which comprises a bearing platform, a first bottom sealing concrete layer, a plurality of steel pipe piles, a plurality of groups of annular anchoring structure bodies and a second bottom sealing concrete layer. The lower ends of the steel pipe piles extend into the stratum, and the upper ends of the steel pipe piles are connected with the bearing platform and the reserved main steel bars extend into the bearing platform. The annular anchoring structural bodies are connected to the first bottom sealing concrete layer in a supporting mode and fixedly arranged on the outer circles of the corresponding steel pipe piles in a sleeving mode, and anchoring ribs at the upper ends of the annular anchoring structural bodies extend upwards into the bearing platform. The second bottom sealing concrete layer is arranged in the foundation pit space outside the annular anchoring structure bodies, and the second bottom sealing concrete layer and the annular anchoring structure bodies are arranged at intervals to form annular isolation seams. According to the novel anchoring structure, vertical sliding between the steel pipe pile and the annular anchoring structure body and vertical sliding between the steel pipe pile and the bearing platform can be effectively resisted, good force transmission of the anchoring structure is achieved, the overall structure is stable, and the force bearing capacity is good.

Description

TECHNICAL FIELD

[0001] The utility model relates to bridge pile cap construction technical field, especially, relate to a steel pipe pile and pile cap anchoring structure. BACKGROUND

[0002] In recent years, in the bridge construction, the cast-in-place pile is as common pile foundation. In the A-shaped single tower cable-stayed bridge of Guangdong delta plain, the seismic fortification intensity is 8 degrees (0.20g) in strong earthquake intensity area, in order to resist strong earthquake force, the main bridge 7# pier pile foundation of the bridge is provided with the permanent steel casing with length 25m, outer diameter 2.5m, and is closely bonded with pile foundation concrete, and constitutes large diameter steel pipe pile (that is, the steel pipe pile is formed by steel casing and cast-in-place pile concrete), and is jointly stressed to participate in the anti-seismic, so that the pile foundation has enough bearing capacity and good bending resistance.

[0003] In the construction of the main bridge 7# pier cap of the bridge, the upper end of the large-diameter steel pipe pile is inserted into the cap, and the anchoring between the steel casing and the cap is required to be reliable so that the steel casing can effectively bear the load and work together with the pile foundation concrete. The bridge cap, as the load transfer body of the large-diameter steel pipe pile and the upper structure of the bridge, is commonly connected with the steel casing in the following ways: (1) the part of the steel casing inserted into the cap is cut into a strip to form a steel strip, and reinforcing steel bars are welded on the steel strip, and the stress-receiving steel bars of the cap pass through the cut-off part of the steel casing; (2) anchor steel bars are welded on the top end plate of the steel casing; (3) a reinforcing bar is placed in the steel casing and filled with core concrete; (4) as disclosed in patent application No. CN201711023517.2, a steel pipe composite pile and cap anchoring structure and its construction method, a horizontal annular bearing plate is sleeved on the outer wall of the steel casing, a stiffening rib is welded on the upper plate surface of the annular bearing plate, one end of the prestressed steel bar is anchored on the annular bearing plate, and the other end is anchored on the interface between the second pouring layer and the third pouring layer of the cap after being tensioned and prestressed; (5) as disclosed in patent application No. CN201620844479.1, a new winged pile, an annular plate is welded on the steel pipe pile, the upper surface of the annular plate is connected with the steel pipe pile through a triangular rib, and a plurality of wings are welded below the annular plate and staggered with the ribs; (6) as disclosed in patent application No. CN202010065869.X, a foundation reconstruction adds a steel pipe pile and a post-added cap anchoring device and its anchoring method, a pile ring is uniformly arranged along the axial direction at the lower part of the steel pipe pile, L-shaped members are uniformly arranged along the axial and radial directions at the lower part of the steel pipe pile, and a reinforcing plate is arranged at the lower part of the pipe pile, and the steel pipe pile, the pile ring, the L-shaped members and the reinforcing plate are poured on the cap to be anchored together with the cap; (7) as disclosed in patent application No. CN201320733682.8, a connection structure of a concrete pipe pile and a cap, the upper end of the pipe pile is connected with the foundation cap, the upper and lower ends of the anchor steel bar are connected with the foundation cap and the pipe pile respectively, the pre-embedded steel bar is located in the pipe pile body, the pipe pile end face is provided with a pile end plate, the end face of the pile end plate is uniformly distributed with a plurality of bolt holes along the circumference, the bottom of the pile end plate is uniformly provided with a plurality of pre-embedded sleeves corresponding to the bolt holes in the pipe pile body, and the bottom end of the anchor steel bar passes through the pile end plate and is connected with the pre-embedded sleeve in the pipe pile.

[0004] The above-mentioned anchoring connection methods have the following defects:

[0005] (1) The first connection method: cutting off a large number of steel strips makes it difficult for the steel casing to fully play its role, the anchoring connection construction is large in amount and low in efficiency, and the construction period of the bridge cap is prolonged.

[0006] (2) The second connection method: the on-site welding work is large in amount, poor in quality reliability and discontinuous in stress, the ordinary steel bars anchored in the cap are perpendicular to the stress direction of the steel bars, which easily leads to tearing failure of the weld.

[0007] (3) The third connecting mode has strict technical requirements, is difficult to be completely realized on a construction site, needs to pour core concrete, needs to spend a lot of manpower and mechanical cooperation, and has very high requirements on the quality of construction personnel.

[0008] (4) The fourth to seventh connecting modes are all provided with annular bearing plates, annular plates, pile rings, L-arm components, reinforcing plates and pile end plates in a horizontal direction of the steel pipe pile, and when the bottom concrete and the pile cap concrete are poured, there are gaps in the bottom surfaces of the annular bearing plates, the annular plates, the pile rings, the L-arm components, the reinforcing plates and the pile end plates, the bubbles in the concrete cannot be discharged outward or the plastic shrinkage of the concrete forms gaps, the annular bearing plates, the annular plates, the pile rings, the L-arm components, the reinforcing plates and the pile end plates are separated from the bottom concrete and the pile cap concrete, the adhesion is not dense, and hidden dangers are left for the engineering quality. Practical new type content

[0009] The utility model provides a steel pipe pile and pile cap anchoring structure to solve the technical problems of poor anchoring connection quality, reliability and bearing capacity of the existing steel pipe pile and pile cap connecting mode.

[0010] The technical scheme adopted by the utility model is as follows:

[0011] A steel pipe pile and pile cap anchoring structure, comprising: a pile cap and a first layer of bottom sealing concrete layer oppositely and intervally arranged, a plurality of vertically arranged steel pipe piles, and a plurality of annular anchoring structure bodies and a second layer of bottom sealing concrete layer connected between the pile cap and the first layer of bottom sealing concrete layer; the first layer of bottom sealing concrete layer is poured on the surface of the pit bottom; the lower end of each steel pipe pile penetrates through the first layer of bottom sealing concrete layer and extends into the underlying stratum, and the upper end of each steel pipe pile is connected to the pile cap and the reserved main reinforcement in the steel pipe pile extends upward into the pile cap; the plurality of annular anchoring structure bodies are arranged one by one corresponding to the plurality of steel pipe piles, each annular anchoring structure body is supported and connected to the first layer of bottom sealing concrete layer and is fixedly sleeved on the outer circle of the corresponding steel pipe pile, and the anchoring reinforcement at the upper end of the annular anchoring structure body extends upward into the pile cap; the second layer of bottom sealing concrete layer is arranged in the pit space outside the plurality of annular anchoring structure bodies, and is intervally arranged between the annular anchoring structure bodies to form an annular isolation joint.

[0012] Further, the steel pipe pile comprises a vertical cast-in-place pile, a steel casing sleeved on the outer circle of the upper end of the cast-in-place pile, and a plurality of reserved main reinforcements embedded in the cast-in-place pile and intervally arranged along the circumference of the cast-in-place pile; the lower ends of the cast-in-place pile and the steel casing respectively penetrate through the first layer of bottom sealing concrete layer and extend into the underlying stratum, and the upper ends of the two respectively abut against the bottom surface of the pile cap, and the annular anchoring structure body is sleeved and fixed on the outer circle of the corresponding steel casing; each reserved main reinforcement is vertically arranged and extends upward into the pile cap.

[0013] Further, the annular anchoring structure comprises an annular anchoring steel framework, mortar pads connected to the bottom and side of the annular anchoring steel framework, and an anchoring concrete layer formed by pouring on the annular anchoring steel framework and the mortar pads; the annular anchoring steel framework is fixedly sleeved on the outer circle of the corresponding steel casing, and is supported by the mortar pads at the bottom and connected to the first layer of bottom sealing concrete layer; the outer annular surface of the anchoring concrete layer is filled with oil paper to form an isolation joint with the second layer of bottom sealing concrete layer.

[0014] Further, the annular anchoring steel framework comprises an anti-skid steel ring group, an anchoring steel ring, and an annular steel cage; the anti-skid steel ring group is sleeved on the outer circle of the corresponding steel casing and extends along the axial direction of the steel casing, and the anti-skid steel ring group is welded and fixed to the outer wall surface of the steel casing; the annular steel cage is sleeved outside the anti-skid steel ring group, and the bottom end is fixedly connected to the mortar pad; the lower end of the anchoring steel ring is inserted into the annular steel cage, and the opposite upper end extends upward into the pile cap.

[0015] Further, the anti-skid steel ring group comprises a plurality of anti-skid steel rings arranged in sequence and spaced along the axial direction of the steel casing; each anti-skid steel ring is welded and fixed to the outer wall surface of the steel casing.

[0016] Further, the annular steel cage comprises an inner layer of mesh, a middle layer of mesh, and an outer layer of mesh arranged in sequence and sleeved from inside to outside, and a stirrup connecting the three together; each of the inner layer of mesh, the middle layer of mesh, and the outer layer of mesh comprises a plurality of annular steels arranged in sequence and spaced along the axial direction of the steel casing, and the adjacent two annular steels in the axial direction of the inner layer of mesh and the outer layer of mesh are further connected by the stirrup, and the adjacent two annular steels in the radial direction at the top and bottom of the inner layer of mesh, the middle layer of mesh, and the outer layer of mesh are further connected by the stirrup.

[0017] Further, the annular anchoring structure further comprises a concrete protective layer prearranged on the inner wall surface of the inner layer of mesh and the outer wall surface of the outer layer of mesh, and the anchoring concrete layer formed by later pouring the annular anchoring steel framework and the mortar pad is connected to the concrete protective layer.

[0018] Further, the anchoring steel ring comprises a plurality of anchoring steels arranged in sequence and spaced along the circumferential direction of the steel pipe pile; the lower end of each anchoring steel is inserted into the annular steel cage, and the upper end of each anchoring steel extends upward into the pile cap.

[0019] Further, the upper and lower ends of each anchoring steel are respectively bent away from the outer side of the steel pipe pile to form an upper bent section and a lower bent section; the upper bent section is located in the pile cap, and the lower bent section is located in the concrete of the first layer of anchoring concrete layer formed by pouring at the lower part of the annular steel cage, and the upper bent section, the lower bent section, and the vertical section therebetween are located in the same vertical plane.

[0020] Further, the thickness of the anchoring concrete layer outside and at the top of the annular anchoring steel framework is not less than 50 mm.

[0021] The utility model has the following beneficial effects:

[0022] The utility model discloses a steel pipe pile and pile cap anchoring structure, (1) can construct the radial, vertical annular anchoring system: through setting up the radial annular anchoring structure body on the outside of each steel pipe pile, and the annular anchoring structure body is fixed with corresponding steel pipe pile and the first layer bottom sealing concrete layer below respectively, thereby with the radial annular anchoring connection of steel pipe pile, constitute the radial annular anchoring system of steel pipe pile and pile cap of '' flat head rivet '' type, realize the radial friction of the adhesion of annular anchoring structure body and steel pipe pile, resist the vertical slip between steel pipe pile and annular anchoring structure body, and when the concrete layer in annular anchoring structure body occurs volume expansion, form radial counterforce under the restraint of the reinforcing steel bar in annular anchoring structure body, will produce radial prestress to the direction of steel pipe pile and make the radial friction of the adhesion of annular anchoring structure body and steel casing, resist the vertical slip between steel pipe pile and annular anchoring structure body, simultaneously anchor the reserved main reinforcing steel bar in steel pipe pile and the anchoring muscle on the top of annular anchoring structure body upwards into the pile cap, and with the vertical annular anchoring connection of pile cap, constitute the vertical annular anchoring system of '' series connection '' type steel pipe pile and pile cap, realize the vertical friction of the adhesion of steel pipe pile and pile cap, resist the vertical slip between steel pipe pile and pile cap, (2) realize the good force transmission of anchoring structure: when the force of bridge superstructure is transmitted to the pile cap, except a part through the pile cap → reserved main reinforcing steel bar → pile cap concrete and steel casing top pressure bearing → steel pipe pile, another part still through the pile cap → annular anchoring structure body → steel casing, thereby make the whole structure stable, and good bearing capacity.

[0023] In addition to the purposes, features and advantages described above, the utility model has other purposes, features and advantages. Below, referring to the drawings, the utility model will be further explained in detail. DRAWINGS

[0024] The drawings that form a part of this application are intended to provide further understanding of the utility model, and the illustrative embodiments of the utility model and the explanation thereof are used to explain the utility model, and do not constitute undue limitation on the utility model. In the drawings:

[0025] Figure 1 It is the steel pipe pile and pile cap anchoring structure elevation schematic view of preferred embodiment of the utility model;

[0026] Figure 2 It is Figure 1 The top view structural schematic view of.

[0027] Legend:

[0028] 1, cast-in-place pile;2, reserved main reinforcing steel bar;3, steel casing;

[0029] 4, anti-slide reinforcing steel ring;

[0030] 501, first layer of bottom sealing concrete layer; 502, second layer of bottom sealing concrete layer;

[0031] 6, annular reinforcing steel; 7, anchoring reinforcing steel; 8, anchoring concrete layer; 9, isolation joint;

[0032] 10, pile cap. DETAILED DESCRIPTION

[0033] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below.

[0034] Referring to Figures 1-2 The preferred embodiment of the present application provides a steel pipe pile and pile cap anchoring structure, comprising: a pile cap 10 and a first layer of bottom sealing concrete layer 501 arranged oppositely and spaced apart, a plurality of vertically arranged steel pipe piles, and a plurality of annular anchoring structure bodies and a second layer of bottom sealing concrete layer 502 connected between the pile cap 10 and the first layer of bottom sealing concrete layer 501. The first layer of bottom sealing concrete layer 501 is poured on the surface of the pit bottom. The lower end of each steel pipe pile extends into the underlying stratum after passing through the first layer of bottom sealing concrete layer 501, and the upper end of each steel pipe pile is connected to the pile cap 10 and the reserved main reinforcing steel 2 therein extends upward into the pile cap 10. The plurality of annular anchoring structure bodies are arranged one-to-one corresponding to the plurality of steel pipe piles, and each annular anchoring structure body is supported and connected to the first layer of bottom sealing concrete layer 501 and is fixedly sleeved on the outer circle of the corresponding steel pipe pile, and the anchoring reinforcing steel at the upper end of the annular anchoring structure body extends upward into the pile cap 10. The second layer of bottom sealing concrete layer 502 is arranged in the pit space outside the plurality of annular anchoring structure bodies, and is arranged spaced apart from each annular anchoring structure body to form an annular isolation joint 9.

[0035] The steel pipe pile and the cap anchoring structure, (1) can construct radial, vertical annular anchoring system: by setting radial annular anchoring structure body outside each steel pipe pile, and the annular anchoring structure body and corresponding steel pipe pile and the first layer bottom sealing concrete layer 501 below are fixed respectively, to be connected with steel pipe pile radial annular anchoring, constitute "flat head rivet" type steel pipe pile and cap radial annular anchoring system, realize annular anchoring structure body and steel pipe pile between the adhesion compactness generates radial friction, resist steel pipe pile and annular anchoring structure body between vertical slip, and when the concrete layer in annular anchoring structure body occurs volume expansion, form radial counterforce under the restraint of the reinforcing steel bar in annular anchoring structure body, will generate radial prestress to the direction of steel pipe pile and be uniformly used to steel pipe pile, make annular anchoring structure body and steel casing between the adhesion compactness generates radial friction, resist steel pipe pile and annular anchoring structure body between vertical slip;Meanwhile, the reserved main reinforcement 2 in steel pipe pile and the anchoring rib at the top of annular anchoring structure body are anchored into the cap 10, and are vertically annularly anchored with the cap 10, to form a "series" type steel pipe pile and cap vertical annular anchoring system, realize the adhesion compactness between steel pipe pile and cap and generate vertical friction, resist vertical slip between steel pipe pile and cap;(2) realize the good force transmission of anchoring structure: when the force of bridge superstructure is transmitted to the cap 10, except a part through cap 10→reserved main reinforcement 2→cap concrete and steel casing top pressure bearing→steel pipe pile, another part still passes through cap 10→annular anchoring structure body→steel casing, so that the overall structure is stable and has good bearing capacity.

[0036] Optionally, as shown in Figure 1 and Figure 2 , the steel pipe pile includes a vertical cast-in-place pile 1, a steel casing 3 wrapped on the outer circle of the upper end of the cast-in-place pile 1, and a plurality of reserved main reinforcements 2 embedded in the cast-in-place pile 1 and sequentially and spaced apart along the circumference of the cast-in-place pile 1. The lower ends of the cast-in-place pile 1 and the steel casing 3 respectively penetrate through the first layer bottom sealing concrete layer 501 and extend into the stratum below, and the upper ends of the two respectively abut against the bottom surface of the cap 10, and the annular anchoring structure is sleeved and fixed on the outer circle of the corresponding steel casing 3. Each reserved main reinforcement 2 is vertically arranged, and the upper end extends upward into the cap 10. In the design, the pile head height of the cast-in-place pile 1 exposed outside is 800 mm, the height of the steel casing 3 is 800 mm, and the height of the reserved main reinforcement 2 is 2300 mm (the anchoring length of the reserved main reinforcement 2 is required to be ≥35d, d is the diameter of the reserved main reinforcement 2, and the diameter of the reserved main reinforcement 2 is 32 mm), so as to ensure the firmness of the anchoring connection between the steel pipe pile and the cap 10.

[0037] Optionally, as shown in Figure 1 , when pouring the first layer bottom sealing concrete layer 501, first level the bottom of the foundation pit, and then pour a layer of concrete with a thickness of 200 mm and a compressive strength grade of C30 on the surface of the bottom of the foundation pit to form the first layer bottom sealing concrete layer 501.

[0038] Optionally, as shown in Figure 1 The annular anchoring structure comprises an annular anchoring reinforcement cage, mortar pads connected to the bottom and side of the annular anchoring reinforcement cage, and an anchoring concrete layer 8 formed by pouring on the annular anchoring reinforcement cage and the mortar pads. The annular anchoring reinforcement cage is fixedly sleeved on the outer circle of the corresponding steel casing 3 and is supported by the mortar pads at the bottom to be connected to the first layer of bottom sealing concrete layer 501. The outer annular surface of the anchoring concrete layer 8 is filled with oil paper to form an isolation joint 9 with the second layer of bottom sealing concrete layer 502.

[0039] Further, as shown in Figure 1 and Figure 2 The annular anchoring reinforcement cage comprises an anti-skid reinforcement ring group, an anchoring reinforcement ring, and a ring-shaped reinforcement cage. The anti-skid reinforcement ring group is sleeved on the outer circle of the corresponding steel casing 3 and extends along the axial direction of the steel casing 3, and the anti-skid reinforcement ring group is welded and fixed to the outer wall surface of the steel casing 3. The ring-shaped reinforcement cage is sleeved outside the anti-skid reinforcement ring group, and the bottom end is fixedly connected to the mortar pad. The lower end of the anchoring reinforcement ring is inserted into the ring-shaped reinforcement cage, and the opposite upper end extends upward into the pile cap 10.

[0040] In this optional solution, as shown in Figure 1 and Figure 2 The anti-skid reinforcement ring group comprises a plurality of anti-skid reinforcement rings 4 arranged in sequence and spaced apart along the axial direction of the steel casing 3. Each anti-skid reinforcement ring 4 is welded and fixed to the outer wall surface of the steel casing 3. In this optional solution, by arranging the anti-skid reinforcement ring group, the roughness of the outer wall surface of the steel casing 3 can be increased, thereby increasing the radial friction between the steel casing 3 and the anchoring concrete layer 8 to resist vertical slip between the steel pipe pile and the anchoring concrete layer 8. In actual design, the anti-skid reinforcement ring 4 uses Φ8mm, HRB400 hot-rolled ribbed steel bars with a length of 7850mm (i.e., the outer circumference of the steel casing 3); during installation, on the steel base surface of the outer wall of the steel casing 3 within the 750mm anti-shear damage effective area at the top of the steel casing 3, at positions 250mm and 500mm from the top surface of the steel casing 3, respectively, 1 Φ8mm anti-skid reinforcement ring 4 is welded horizontally; the anti-skid reinforcement ring 4 and the steel casing 3 are connected by full welding using manual arc welding, so that the anti-skid reinforcement ring 4 and the steel casing 3 are firmly welded, and after welding, the welding slag is cleaned, and the welding seam is full, flat, smooth, without slag inclusion, air bubbles, or cracks.

[0041] In this optional solution, as shown in Figure 1 and Figure 2As shown, the annular reinforcement cage comprises an inner layer of reinforcement mesh, a middle layer of reinforcement mesh and an outer layer of reinforcement mesh which are sequentially sleeved from inside to outside, and stirrups which connect the three together. The inner layer of reinforcement mesh, the middle layer of reinforcement mesh and the outer layer of reinforcement mesh each comprise a plurality of annular steels 6 which are sequentially and spaced apart along the axial direction of the steel casing 3, and the axially adjacent two annular steels 6 of the inner layer of reinforcement mesh and the outer layer of reinforcement mesh are further connected by a stirrup, and the radially adjacent two annular steels 6 at the top and bottom ends of the inner layer of reinforcement mesh, the middle layer of reinforcement mesh and the outer layer of reinforcement mesh are further connected by a stirrup. When vertical slip occurs between the steel pipe pile and the anchoring concrete layer 8, the anchoring concrete layer 8 will expand in volume, generating radial stress to the outside of the anchoring concrete layer 8, and under the constraint of the annular reinforcement cage, a radial counterforce is formed, which will generate radial prestress to the inside of the anchoring concrete layer 8 (towards the direction of the steel pipe pile) and uniformly act on the steel pipe pile, so that the anchoring concrete layer 8 and the steel casing 3 are tightly bonded to generate radial friction, resisting the vertical slip between the steel pipe pile and the anchoring concrete layer 8.

[0042] In actual design, the annular steels 6 of the inner layer of reinforcement mesh are Φ8mm, HRB400 hot-rolled ribbed steel bars with a length of 8040mm, the annular steels 6 of the middle layer of reinforcement mesh are Φ8mm, HRB400 hot-rolled ribbed steel bars with a length of 8830mm, and the annular steels 6 of the outer layer of reinforcement mesh are Φ8mm, HRB400 hot-rolled ribbed steel bars with a length of 9610mm. During installation, first, the annular reinforcement cage with a width of 250mm and a height of 700mm is installed horizontally along the radial direction of the outside of the steel casing 3 on the top surface of the first layer of bottom sealing concrete layer 501, and during installation, the main steels at both ends of the annular reinforcement cage are one-to-one corresponding to each other and are firmly connected by manual electric arc welding. Two annular steels 6 are evenly arranged at the middle position of the height side of the annular reinforcement cage, and the spacing between adjacent annular steels 6 is 217mm. One annular steel 6 is evenly arranged at the middle position of the width side of the annular reinforcement cage, and the spacing between adjacent annular steels 6 is 105mm. The stirrups are Φ6mm, HRB400 hot-rolled ribbed steel bars, and 40 stirrups are evenly arranged along the radial direction of the steel casing 3. The spacing between adjacent stirrups on the outside of the annular reinforcement cage is 234mm, and the spacing between adjacent stirrups on the inside of the annular reinforcement cage is 195mm.

[0043] Preferably, the annular anchoring structure further comprises a concrete protective layer which is provided in advance on the inner wall surface of the inner layer of reinforcement mesh and the outer wall surface of the outer layer of reinforcement mesh, and is connected to the anchoring concrete layer 8 formed by post-pouring the annular anchoring steel reinforcement framework and the mortar cushion. In design, the thickness of the outer concrete protective layer is 50mm, and the thickness of the inner concrete protective layer is 20mm.

[0044] In this optional solution, as shown in Figure 1 and Figure 2As shown, the anchoring steel ring comprises a plurality of anchoring steels 7 arranged along the circumference of the steel pipe pile in sequence. The lower end of each anchoring steel 7 is inserted into the ring-shaped steel cage, and the upper end of each anchoring steel 7 extends upward into the pile cap 10. In this optional scheme, the anchoring steel ring has the following effects: (1) reducing the welding workload between the anchoring steel 7 and the steel casing 3 on the construction site, avoiding poor welding quality of the anchoring steel 7; (2) when the anchoring steel 7 is installed, the safety and reliability are high, the operation is convenient and fast, the construction efficiency is greatly improved, the construction period is shortened, and the construction cost is saved; (3) the anchoring steel 7 and the reserved main steel 2 are anchored into the pile cap 10 and connected with the vertical ring-shaped anchoring of the pile cap 10, forming a "series" type vertical ring-shaped anchoring system of the steel pipe pile and the pile cap 10, ensuring the effective connection between the steel pipe pile and the pile cap 10, and enhancing the overall stability and safety of the pile cap 10 structure through the vertical ring-shaped anchoring system, thereby improving the anchoring quality reliability of the steel pipe pile and the pile cap 10; when vertical slip occurs between the steel pipe pile and the pile cap 10, the anchoring steel 7 and the reserved main steel 2 will generate vertical anti-sliding force on the steel pipe pile, making the steel pipe pile and the pile cap 10 adhere tightly and generate vertical friction force, resisting the vertical slip between the steel pipe pile and the pile cap 10; (4) when the force transmitted by the bridge superstructure to the pile cap, in addition to a part of the force being transmitted through the pile cap 10→ reserved main steel 2→ pile cap concrete and bearing pressure between the top of the steel casing 3→ steel pipe pile, another part of the force can also be transmitted through the pile cap 10→ anchoring steel 7→ anchoring concrete layer 8→ anchoring concrete layer 8 and the contact surface of the anchoring concrete layer 8 and the steel casing 3 and the convex anti-sliding steel ring 4 on the contact surface→ steel casing 3.

[0045] Further, as Figure 1As shown, the upper and lower ends of each anchoring steel bar 7 are respectively bent to form an upper bent section and a lower bent section away from the outer side of the steel pipe pile. The upper bent section is located in the pile cap 10, and the lower bent section is located in the concrete of the first layer of anchoring concrete layer 8 formed by pouring the lower part of the ring-shaped steel reinforcement cage. The upper bent section, the lower bent section, and the vertical section therebetween are located in the same vertical plane. In actual design, the anchoring steel bar 7 is a Φ20mm, HRB400 hot-rolled ribbed steel bar with a length of 2400mm. At one end of the anchoring steel bar 7, a 100mm long, 90° angle bent short side is processed to form the lower bent section. At the other end of the anchoring steel bar 7, a 1400mm long, 30° angle bent inclined side is processed to form the upper bent section. After processing, the upper bent section at the top of the anchoring steel bar 7 and the lower bent section at the bottom of the anchoring steel bar 7 are bent in the same direction, and the upper bent section, the vertical section, and the lower bent section are in the same plane. During design and installation, 40 anchoring steel bars 7 are vertically and uniformly installed in the ring-shaped steel reinforcement cage along the radial direction of the outer side of the steel casing 3. The spacing between adjacent anchoring steel bars 7 is 184mm. During installation, the lower bent section end of the anchoring steel bar 7 is inserted into the concrete of the first layer of anchoring concrete layer 8 from top to bottom at a position 20mm away from the top surface of the first layer of bottom sealing concrete layer 501. The upper bent section end of the anchoring steel bar 7 is directed upward away from the top surface of the first layer of bottom sealing concrete layer 501, and the upper bent section, the vertical section, and the lower bent section of the anchoring steel bar 7 are installed away from the steel casing 3. After installation, the distance between the anchoring steel bar 7 and the outer wall of the steel casing 3 is 50mm. The length of the anchoring steel bar 7 anchored in the anchoring concrete layer 8 is 700mm, and the length of the anchoring steel bar 7 anchored in the pile cap 10 is 1550mm, to ensure the firmness of the anchoring connection between the steel pipe pile and the pile cap 10.

[0046] Preferably, the thickness of the anchoring concrete layer 8 outside the annular anchoring steel framework and at the top end is not less than 50 mm. When the anchoring concrete layer 8 expands in volume, a radial counterforce is formed under the constraint of the annular steel reinforcement cage, which generates a radial prestress on the inside of the anchoring concrete layer 8 (towards the steel pipe pile) and uniformly acts on the steel pipe pile, so that the anchoring concrete layer 8 and the steel casing 3 are tightly bonded and generate a radial friction force, resisting the vertical slip between the steel pipe pile and the anchoring concrete layer 8; when vertical slip occurs between the steel pipe pile and the anchoring concrete layer 8, the anchoring steel bars 7 in the anchoring concrete layer 8 will generate an upward anti-sliding force on the anchoring concrete layer 8, causing the anchoring concrete layer 8 to resist shear failure, forming a shear failure crack failure surface that intersects the outer peripheral wall surface of the steel casing 3 and the top surface of the first layer of bottom sealing concrete layer 501 at an angle of 45°. Among them: the part of the anchoring concrete layer 8 above the shear failure crack failure surface is the shear failure effective area of the anchoring concrete layer 8, which plays a shear role and resists the vertical slip between the steel pipe pile and the anchoring concrete layer 8; the part of the anchoring concrete layer 8 below the shear failure crack failure surface is the shear failure failure area of the anchoring concrete layer 8, i.e. the approximately triangular annular shear failure failure area of the anchoring concrete layer 8 with the first layer of bottom sealing concrete layer 501 top surface and the steel casing 3 outer wall intersection as the center and the maximum particle size of the coarse aggregate used in the anchoring concrete layer 8 as the width and height, which loses the shear role and cannot resist the vertical slip between the steel pipe pile and the anchoring concrete layer 8.

[0047] During installation, an annular formwork is installed on the first layer of bottom sealing concrete layer 501 top surface outside the annular steel reinforcement cage. The thickness of the anchoring concrete layer 8 outside the annular anchoring steel framework and at the top end is not less than 50 mm during installation of the annular formwork. After the anchoring steel bars 7, the annular steel reinforcement 6 and the anti-sliding steel reinforcement ring 4 are installed and the installation quality is inspected and accepted, the anchoring concrete layer 8 with a width of 320 mm and a height of 800 mm is poured on the first layer of bottom sealing concrete layer 501 top surface. The anchoring concrete layer 8 uses C40 micro-expanding concrete. During pouring, the anchoring concrete layer 8 is poured and formed in three layers, with a pouring thickness of 250-300 mm for each layer, so that the anchoring concrete layer 8 is poured to be flush with the top surface of the steel casing 3. Before the anchoring concrete layer 8 is initially set, the anchoring concrete layer 8 must be vibrated for the second time to prevent the aggregate in the anchoring concrete layer 8 from sinking and separating from the anchoring steel bars 7, the annular steel reinforcement 6, the anti-sliding steel reinforcement ring 4 and the steel casing 3 when the anchoring concrete layer 8 is in plastic shrinkage, thereby reducing the gripping force between the anchoring concrete layer 8 and the anchoring steel bars 7, the annular steel reinforcement 6 and the anti-sliding steel reinforcement ring 4, or the bonding force between the anchoring concrete layer 8 and the steel casing 3.

[0048] After the annular formwork is removed, a layer of oil paper with a thickness of 0.2 mm is arranged outside the anchoring concrete layer 8, and the anchoring concrete layer 8 and the second layer of bottom sealing concrete 502 are filled and isolated to form an isolation joint 9, so as to prevent the second layer of bottom sealing concrete 502 from damaging the anchoring concrete layer 8 when shrinkage occurs, and to be more beneficial to the expansion of the anchoring concrete layer 8. On the top surface of the first layer of bottom sealing concrete 501 outside the anchoring concrete layer 8, the second layer of C30 bottom sealing concrete 502 is poured to be flush with the top surface of the anchoring concrete layer 8 and the top surface of the steel casing 3.

[0049] On the top surface of the second layer of bottom sealing concrete 502, the top surface of the isolation joint 9, the top surface of the anchoring concrete layer 8, the top surface of the steel casing 3 and the top surface of the cast-in-place pile 1, the construction of anchoring the reserved main steel bars 2 and the anchoring steel bars 7 into the pile cap 10, the construction of lightning protection grounding, the installation of the steel bars of the pile cap 10, the installation of the cooling pipes and the installation of the embedded components are sequentially completed, and after the installation quality is accepted, the pile cap 10 formwork and the pile cap 10 concrete are installed.

[0050] After the pile cap 10 is constructed, the reserved main steel bars 2 and the anchoring steel bars 7 are anchored into the pile cap 10 and connected with the vertical annular anchoring of the pile cap 10, so as to ensure the firmness of the anchoring connection between the steel pipe pile and the pile cap 10, to form a vertical annular anchoring system of the “series connection” type steel pipe pile and the pile cap 10, to ensure the effective connection between the steel pipe pile and the pile cap 10, and to enhance the overall stability and safety of the pile cap 10 structure through the vertical annular anchoring system, and to further improve the anchoring quality reliability of the steel pipe pile and the pile cap 10.

[0051] The above only describes preferred embodiments of the utility model, and is not used for limiting the utility model. For those skilled in the art, the utility model can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A steel pipe pile and pile cap anchoring structure characterized by, The steel pipe pile and cap anchoring structure comprises a bearing platform (10) and a first layer of bottom sealing concrete layer (501) arranged oppositely and spaced apart, a plurality of steel pipe piles arranged vertically, and a plurality of ring-shaped anchoring structures and a second layer of bottom sealing concrete layer (502) connected between the bearing platform (10) and the first layer of bottom sealing concrete layer (501). The first layer of bottom sealing concrete layer (501) is poured on the surface of the bottom of the foundation pit. The lower end of each steel pipe pile extends into the underlying stratum after penetrating the first layer of bottom sealing concrete layer (501), and the upper end of each steel pipe pile is connected to the bearing platform (10) and the reserved main reinforcement (2) in the steel pipe pile extends upward into the bearing platform (10). Each ring-shaped anchoring structure corresponds to a steel pipe pile, and each ring-shaped anchoring structure is supported and connected to the first layer of bottom sealing concrete layer (501) and is fixedly sleeved on the outer circle of the corresponding steel pipe pile, and the anchoring reinforcement at the upper end of the ring-shaped anchoring structure extends upward into the bearing platform (10). The second layer of bottom sealing concrete layer (502) is arranged in the space of the foundation pit outside the plurality of ring-shaped anchoring structures, and is spaced apart from each ring-shaped anchoring structure to form a ring-shaped isolation joint (9).

2. The steel pipe pile and cap anchoring structure according to claim 1, wherein the steel pipe pile comprises a cast-in-place pile (1) arranged vertically, a steel casing (3) sleeved on the outer circle of the upper end of the cast-in-place pile (1), and a plurality of reserved main reinforcements (2) embedded in the cast-in-place pile (1) and arranged spaced apart along the circumference of the cast-in-place pile (1). The lower end of each of the cast-in-place pile (1) and the steel casing (3) extends into the underlying stratum after penetrating the first layer of bottom sealing concrete layer (501), and the upper end of each of the cast-in-place pile (1) and the steel casing (3) abuts against the bottom surface of the bearing platform (10), and the ring-shaped anchoring structure is fixedly sleeved on the outer circle of the corresponding steel casing (3). Each reserved main reinforcement (2) is arranged vertically, and the upper end of each reserved main reinforcement (2) extends upward into the bearing platform (10).

3. The steel pipe pile and cap anchoring structure according to claim 2, wherein the ring-shaped anchoring structure comprises a ring-shaped anchoring reinforcement cage, mortar pads connected to the bottom and sides of the ring-shaped anchoring reinforcement cage, and an anchoring concrete layer (8) poured on the ring-shaped anchoring reinforcement cage and the mortar pads. The ring-shaped anchoring reinforcement cage is fixedly sleeved on the outer circle of the corresponding steel casing (3), and is supported and connected to the first layer of bottom sealing concrete layer (501) by the mortar pads at the bottom. The outer ring surface of the anchoring concrete layer (8) is filled with oil paper to form an isolation joint (9) with the second layer of bottom sealing concrete layer (502).

4. The steel pipe pile and cap anchoring structure according to claim 3, wherein the ring-shaped anchoring reinforcement cage comprises a sliding-resistant reinforcement ring group, an anchoring reinforcement ring, and a ring-shaped reinforcement cage. The sliding-resistant reinforcement ring group is sleeved on the outer circle of the corresponding steel casing (3) and extends along the axial direction of the steel casing (3), and the sliding-resistant reinforcement ring group is welded and fixed to the outer wall of the steel casing (3). The ring-shaped reinforcement cage is sleeved outside the sliding-resistant reinforcement ring group, and the bottom end of the ring-shaped reinforcement cage is fixedly connected to the mortar pad. The lower end of the anchoring reinforcement ring is inserted into the ring-shaped reinforcement cage, and the opposite upper end of the anchoring reinforcement ring extends upward into the bearing platform (10).

5. The steel pipe pile and cap anchoring structure according to claim 4, wherein ​ ​ ​ ​ The anti-sliding steel reinforcement ring set comprises a plurality of anti-sliding steel reinforcement rings (4) arranged along the axial direction of the steel casing (3) in sequence at intervals. Each anti-sliding steel reinforcement ring (4) is welded and fixed to the outer wall surface of the steel casing (3).

6. The steel pipe pile and cap anchoring structure according to claim 4, characterized in that, The annular steel reinforcement cage comprises an inner layer of reinforcement mesh, a middle layer of reinforcement mesh and an outer layer of reinforcement mesh arranged in sequence from inside to outside, and stirrups connecting the three together. The inner layer of reinforcement mesh, the middle layer of reinforcement mesh and the outer layer of reinforcement mesh each comprise a plurality of annular steel reinforcements (6) arranged along the axial direction of the steel casing (3) in sequence at intervals, and the axially adjacent two annular steel reinforcements (6) of the inner layer of reinforcement mesh and the outer layer of reinforcement mesh are further connected by a stirrup, and the radially adjacent two annular steel reinforcements (6) at the top and bottom ends of the inner layer of reinforcement mesh, the middle layer of reinforcement mesh and the outer layer of reinforcement mesh are further connected by a stirrup.

7. The steel pipe pile and cap anchoring structure according to claim 6, characterized in that, The annular anchoring structure further comprises a concrete protective layer provided in advance on the inner wall surface of the inner layer of reinforcement mesh and the outer wall surface of the outer layer of reinforcement mesh, and the anchoring concrete layer (8) formed by post-casting the annular anchoring steel reinforcement cage and the mortar cushion block is connected to the concrete protective layer.

8. The steel pipe pile and cap anchoring structure according to claim 4, characterized in that, The anchoring steel reinforcement ring comprises a plurality of anchoring steel reinforcements (7) arranged along the circumferential direction of the steel pipe pile in sequence at intervals. The lower end of each anchoring steel reinforcement (7) is inserted into the annular steel reinforcement cage, and the upper end of each anchoring steel reinforcement (7) extends upward into the cap (10).

9. The steel pipe pile and cap anchoring structure according to claim 8, characterized in that, The upper and lower ends of each anchoring steel reinforcement (7) are respectively bent away from the outer side of the steel pipe pile to form an upper bent section and a lower bent section; The upper bent section is located in the cap (10), the lower bent section is located in the concrete of the first layer of anchoring concrete layer (8) formed by the first pouring of the annular steel reinforcement cage, and the upper bent section, the lower bent section and the vertical section therebetween are located in the same vertical plane.

10. The steel pipe pile and cap anchoring structure according to claim 8, characterized in that, The thickness of the anchoring concrete layer (8) outside and at the top of the annular anchoring steel reinforcement cage is not less than 50 mm.

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