Construction method of assembly type prefabricated steel pipe-pipe pile composite high-strength toughness stand column pile

Abstract

The invention discloses a construction method of an assembly type prefabricated steel pipe-pipe pile composite high-strength toughness stand column pile, and belongs to the field of foundation pit supporting. According to the stand column pile construction method, an adopted stand column pile comprises a foundation pile section, a bottom plate section, a stand column section and a supporting section, the construction method comprises the steps of foundation pile section construction, bottom plate section construction, stand column section and supporting section construction, foundation pit excavation and supporting construction and foundation pit bottom plate and main body structure construction, and the foundation pile section is a prefabricated pipe pile; by improving the steel-concrete composite structure of the prefabricated steel pipe pile, the strength and toughness of the pile body of the stand column pile are improved, the structural strength of the stand column section is improved, brittle failure of the stand column pile in the construction process is avoided, holding and pressing construction can be conducted through a static pressure pile machine, and the optimal design of the construction sequence is matched. The construction efficiency of the stand column pile is greatly improved; moreover, the stand column section is assembled by adopting a socket structure, so that 100% recycling can be realized, the construction cost is reduced, and the economical efficiency of the stand column pile is remarkably improved.

Description

Technical Field

[0001] The invention relates to a deep foundation pit support construction method, and more specifically to a method for constructing assembled prefabricated steel pipe-pile composite high-strength and toughness column piles. Background Art

[0002] With the acceleration of urbanization and the continuous deepening of underground space development, deep foundation pit projects play an increasingly important role in modern building and infrastructure construction. As the key vertical load-bearing components in the foundation pit support system, the scientificity, efficiency and economy of the construction method of column piles directly affect the progress, quality and cost of the entire project. Traditional column pile construction methods (such as cast-in-place pile construction, steel pipe pile construction, etc.) have many limitations in terms of construction period, material properties, connection strength and economy.

[0003] 1. Limitations of cast-in-place pile construction methods

[0004] Cast-in-place pile construction is to form the pile body by drilling holes on site, installing steel cages, pouring concrete and curing. Although cast-in-place piles have a high bearing capacity, their construction method has the following problems:

[0005] Long construction period: Cast-in-place pile construction requires multiple steps such as drilling, hole cleaning, steel cage installation, concrete pouring and maintenance. The construction period is long and it is difficult to meet the needs of rapid construction.

[0006] Serious environmental pollution: A large amount of mud will be produced during the drilling process, which will pollute the environment and the cost of mud treatment is high;

[0007] Materials are not recyclable: Once the cast-in-place piles are constructed, they cannot be recycled, resulting in a waste of resources;

[0008] Insufficient connection stiffness: The connection between the pile body and the upper steel structure relies on concrete filling, which has low connection stiffness and long consolidation time, affecting the stability of the overall structure;

[0009] High construction accuracy requirements: The verticality and position accuracy of the bored piles are difficult to guarantee, and problems such as hole wall collapse and diameter shrinkage are prone to occur, affecting the quality of the pile body.

[0010] 2. Limitations of steel pipe pile construction methods

[0011] Steel pipe pile construction uses steel pipes as pile bodies and drives them into the ground by static pressure or hammering. Although steel pipe pile construction is fast, there are the following problems:

[0012] High cost: The material cost of steel pipe piles is high, especially in large diameter and deep foundation pit projects, which makes them less economical;

[0013] Poor pull-out resistance: Steel pipe piles have insufficient pull-out resistance and are prone to pull-out failure under vertical loads;

[0014] Material waste: Steel pipe piles need to be cut when they are recycled, resulting in material waste and making it difficult to meet the requirements of green construction;

[0015] Poor anti-corrosion performance: In coastal areas or areas with high groundwater levels, steel pipe piles are susceptible to corrosion, which affects their service life;

[0016] Insufficient connection node strength: The connection node between the steel pipe pile and the superstructure is weak, which is prone to connection failure.

[0017] In recent years, prefabricated pipe pile technology has gradually become a research hotspot due to its advantages of standardized production, fast construction speed, and controllable quality. Prefabricated pipe piles (such as prestressed concrete pipe piles, PHC pipe piles) have the advantages of fast construction speed and controllable quality. However, the impact resistance and toughness of prefabricated pipe piles under complex geological conditions still need to be further improved. In practical applications, there are still the following problems:

[0018] Insufficient impact resistance: Prefabricated pipe piles are prone to brittle failure under complex geological conditions (such as soft soil layers, sand layers, etc.) and have poor impact resistance;

[0019] Insufficient connection node strength: The connection node strength between the prefabricated pipe pile and the upper structure (such as steel lattice column) is weak, and it is easy to fail under load;

[0020] Insufficient material toughness: Prefabricated pipe piles are not tough enough and are prone to local damage or deformation under complex working conditions;

[0021] High construction accuracy requirements: The pile sinking construction of prefabricated pipe piles requires precise positioning and verticality control, otherwise the pile body may tilt or be damaged.

[0022] In order to improve the impact resistance and toughness of prefabricated pipe piles, there are also structural optimization solutions proposed in the prior art, such as the "Construction method of prefabricated pipe piles as supporting columns in foundation pits" disclosed in patent publication number CN114351720A, which uses prefabricated pipe piles as column piles and sets steel sleeves and steel cages inside the pipe piles to improve the overall performance of the pipe piles. However, there are still the following shortcomings:

[0023] Complex construction: complex steel cage arrangement and concrete pouring are required inside the piles, which makes the construction difficult;

[0024] Insufficient economy: the material cost is high, and additional connectors and core concrete are required during the construction process, which increases the project cost;

[0025] Insufficient adaptability: Under complex geological conditions (such as soft soil layers, sand layers, etc.), it is still difficult to completely avoid brittle failure of optimized pipe piles.

[0026] In addition, in recent years, the construction method of combined column piles has gradually become a research hotspot. For example, the patent publication number CN215669540U discloses a "column pile composed of a prestressed high-strength concrete pipe pile and a steel lattice column". It improves the bearing capacity of the column pile by end plate connection and core concrete pouring, but requires multiple welding and pouring at the construction site, with low construction efficiency and complex construction; and the material cost is high, and additional connectors and core concrete are required during the construction process, which increases the project cost and is not economical enough; and, although the connection strength is improved by the end plate connection, the shear resistance and fatigue resistance of the connection node still need to be further optimized under complex working conditions. Summary of the invention

[0027] 1. Technical problem to be solved by the invention

[0028] The purpose of the present invention is to solve the problems of low construction efficiency, poor recyclability, low strength of pile body connection nodes, poor pile body strength and toughness, and high construction cost of existing column piles, and provide a prefabricated steel pipe-pile composite high-strength toughness column pile construction method. The technical scheme of the present invention is adopted, and the column pile is composed of a foundation pile section, a bottom plate section, a column section and a support section, wherein the foundation pile section is a prefabricated pipe pile, and the column section is a prefabricated steel pipe pile. By improving the steel-concrete composite structure of the prefabricated steel pipe pile, the pile body strength and toughness of the column pile are improved, and the structural strength of the column section is improved. The static pressure pile machine can be used for holding pressure construction, and the construction efficiency of the column pile is greatly improved by optimizing the construction sequence; and the column section adopts a socket structure assembly, which can be 100% recycled, reducing the construction cost and significantly improving the economy of the column pile. In addition, the column pile has a high strength of the connection node, which ensures the stability of the deep foundation pit support.

[0029] 2. Technical solution

[0030] In order to achieve the above object, the technical solution provided by the present invention is:

[0031] The method for constructing assembled prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention is as follows:

[0032] The column piles used in the construction method include a foundation pile section, a bottom plate section, a column section and a support section, wherein the foundation pile section is a prefabricated pipe pile; the column section is a prefabricated steel pipe pile, including a middle pile body and end reinforcement joints fixedly arranged at both ends of the middle pile body, the outer side of the middle pile body is a thin-walled steel pipe, the thin-walled steel pipe has a high-strength concrete layer, and the high-strength concrete layer has a reinforcement skeleton; the support section includes a support steel pipe, and both ends of the support steel pipe have pipe end connection parts;

[0033] The construction method comprises the following steps:

[0034] S1. Construction of foundation pile sections: Use a static pile driver to press the foundation pile sections into the designed elevation. During the pile pressing process, the pile pressing speed is controlled at 0.5-1.0 m / min.

[0035] S2. Bottom plate section construction: Apply structural adhesive to the corresponding position of the bottom plate section, hoist and install the bottom plate section on the top of the foundation pile section, and reinforce and fix the bottom plate section and the foundation pile section;

[0036] S3. Construction of column segments and support segments: For shallow foundation pits, first, each column segment is connected by socket fitting with the support segment and assembled with pins or bolts, then hoisted as a whole and socket fitting with the bottom plate segment and assembled with pins or bolts, and a static pile driver is used to hold and press the piles at one time, and finally, the pile body of the column pile is pressed to the designed elevation with the pile driver; For deep foundation pits, the column segments and support segments are installed section by section, and then a static pile driver is used to hold and press the piles in sections, and finally, the pile body of the column pile is pressed to the designed elevation with the pile driver, wherein the first column segment is socket fitting with the bottom plate segment and assembled with pins or bolts, and the remaining column segments are socket fitting with the support segments and assembled with pins or bolts;

[0037] S4. Excavation of foundation pit and support construction: excavate the foundation pit soil layer by layer, and install the support beam layer by layer from top to bottom; when connecting the support beam with the support section, first weld a connecting support plate and a number of support section bolts on the support section, the connecting support plate is located at the lower end of the support steel pipe, and the support section bolts are distributed on the outer periphery of the support steel pipe, and then the support beam is connected to the support section by cast-in-place;

[0038] S5. Construction of foundation pit floor and main structure: After excavating the foundation pit soil to the base, the floor section is exposed and the foundation pile section is located in the base stratum. First, a water stop plate and several floor section bolts are welded on the periphery of the floor section, and then the foundation pit floor and main structure are constructed, and the floor section is cast-in-place connected with the foundation pit floor.

[0039] Furthermore, the bottom plate section adopts a press-in expansion connection structure, including an external connection steel pipe and a core pipe, the upper end of the outer tube body of the external connection steel pipe is provided with an upper connection part for assembling and connecting with the end reinforcement joint of the column section, the lower end of the outer tube body is provided with an expansion connection pipe that can be inserted into the central through hole of the foundation pile section, a plurality of openings are provided on the tube wall of the expansion connection pipe, and expansion claws are formed between adjacent openings, and the inner side wall of the expansion claw is an inverted cone surface; the core pipe is arranged in the inner hole of the external connection steel pipe, and the upper end of the core pipe has a core pipe pushing part;

[0040] The bottom plate section construction of step S2 above includes the following sub-steps:

[0041] S2-1. Apply structural adhesive to the outside of the expansion connection pipe, and hoist and install the external connection steel pipe on the top of the foundation pile section so that the expansion connection pipe is inserted into the central through hole of the foundation pile section;

[0042] S2-2, placing the core tube into the inner hole of the outer connecting steel tube, using a static pile driver in conjunction with a pile driver to press the core tube into the outer connecting steel tube so that the expansion claws expand outward, and the expanded expansion claws press against the inner wall of the central through hole to form a fixed connection;

[0043] S2-3. Weld or bolt the reinforcement connector between the outer side of the external connecting steel pipe and the upper end surface of the foundation pile segment.

[0044] Furthermore, the outer diameter of the outer tube body is larger than the outer diameter of the expansion connecting tube, and a limiting step that can cooperate with the upper end surface of the foundation pile segment is formed at the upper end of the expansion connecting tube. During the static pressure piling process, the limiting step abuts against the upper end surface of the foundation pile segment to transmit the pile pressing pressure.

[0045] Furthermore, the bottom plate section adopts a sleeve connection structure, which includes a receiving steel pipe, the upper end of which is provided with a column connection part for assembling and connecting with the end reinforcement joint of the column section, and the lower end of which is provided with a coaxial outer sleeve and inner sleeve through a conversion part, the inner diameter of the outer sleeve is adapted to the outer diameter of the pile end connection part of the foundation pile section, and the outer diameter of the inner sleeve is adapted to the inner diameter of the central through hole of the foundation pile section; the height of the pile end connection part at the upper end of the foundation pile section is greater than the height of the outer sleeve, and bolt holes for bolting with the pile end connection part at the upper end of the foundation pile section are also provided around the conversion part;

[0046] The bottom plate section construction of step S2 above includes the following sub-steps:

[0047] S2-1. Apply structural adhesive to the outside of the inner casing, and install the receiving steel pipe on the top of the foundation pile section, so that the inner casing is inserted into the central through hole of the foundation pile section, and the outer casing is sleeved on the outside of the pile end connection part at the upper end of the foundation pile section;

[0048] S2-2, using bolts to fix the conversion part to the pile end connection part at the upper end of the foundation pile segment;

[0049] S2-3. Weld the outer casing to the pile end connection.

[0050] Furthermore, the bottom plate section and the foundation pile section are connected by an anti-pullout connection plug-in, the bottom plate section includes a steel casing, embedded rods, stirrups and concrete, the embedded rods are circumferentially distributed around the steel casing, and each embedded rod extends to the bottom end face of the bottom plate section and is provided with a lower end connecting sleeve, each lower end connecting sleeve is internally threadedly connected with a connecting plug rod, the embedded rods are connected by stirrups, and the concrete is filled in the steel casing; the upper end of the foundation pile section is circumferentially distributed with corresponding pipe pile embedded pull rods, the pipe pile embedded pull rod extends to the upper end face of the foundation pile section and is provided with an upper end connecting sleeve, the upper end connecting sleeve is sequentially provided with a spring, a washer, a locking plate and a nut sleeve from bottom to top, the upper end of the spring is against the washer, the locking plate is located above the washer, and the locking plate and the lower end of the nut sleeve are matched with an inverted cone structure, and the nut sleeve is threadedly fixed to the upper end of the upper connecting sleeve;

[0051] During the bottom plate segment construction process of the above step S2, the bottom plate segment is hoisted to the top of the foundation pile segment, so that the connecting rod on the lower end surface of the bottom plate segment is aligned with the nut sleeve on the foundation pile segment and plugged into and connected, and the cone at the lower end of the connecting rod is locked with a locking plate to achieve a fixed connection between the bottom plate segment and the foundation pile segment.

[0052] Furthermore, after the construction of step S5 is completed, the support dismantling and recycling step S6 is entered; in the support dismantling and recycling step S6, the support beams and support sections are dismantled layer by layer from top to bottom, and the column sections are dismantled and recycled, and the repaired column sections are matched and designed and reused according to the design requirements of the next project.

[0053] Furthermore, in the column section, a plurality of reinforcing ribs are circumferentially distributed on the inner wall of the thin-walled steel pipe, and the end reinforcing joints are respectively welded and fixed to the thin-walled steel pipe and the reinforcing ribs; the reinforcing skeleton includes a steel cage and an FRP fiber grid which are located on the inner side of the thin-walled steel pipe and arranged in layers.

[0054] Furthermore, the center of the high-strength concrete layer has a through hole coaxial with the thin-walled steel pipe, and the high-strength concrete layer is cast by regenerated aerated high-strength concrete mixed with polypropylene fiber.

[0055] Furthermore, sensor installation holes for installing foundation pit section monitoring sensors and wireless communication modules are reserved in the high-strength concrete layer.

[0056] Furthermore, in step S3, in the case where the outer diameter of the foundation pile segment is larger than the outer diameter of the column segment, a clamp used in conjunction with a static pile driver is used to hold and press the column segment, the clamp is composed of two or more clamping plates, and both upper and lower ends of the clamping plates have convex edges extending outward, and the outer diameter of the clamp engaged on the column segment is equivalent to the outer diameter of the foundation pile segment; when constructing the column segment, the clamp is installed on the static pile driver, and the static pile driver holds the column segment through the clamp to perform pile pressing operations.

[0057] 3. Beneficial effects

[0058] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0059] (1) The present invention discloses a method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles. The column piles used in the method include a foundation pile section, a bottom plate section, a column section and a support section. The construction method includes foundation pile section construction, bottom plate section construction, column section and support section construction, foundation pit excavation and support construction, and foundation pit bottom plate and main structure construction. The foundation pile section is a prefabricated pipe pile, and the column section is a prefabricated steel pipe pile. By improving the steel-concrete composite structure of the prefabricated steel pipe pile, the pile body strength and toughness of the column pile are improved, the structural strength of the column section is improved, and the brittle damage of the column pile during the construction process is avoided. The static pressure pile driver can be used for the construction, and the construction efficiency of the column pile is greatly improved by combining with the optimized design of the construction sequence. In addition, the column section is assembled with a socket structure and can be 100% recycled, which reduces the construction cost and significantly improves the economy of the column pile.

[0060] (2) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention adopts a press-in expansion connection structure for the bottom plate section, including an outer connecting steel pipe and a core pipe. The lower end of the outer pipe body is provided with an expansion connection pipe that can be inserted into the central through hole of the foundation pile section. The pipe wall of the expansion connection pipe is provided with a plurality of openings, and expansion claws are formed between adjacent openings. The core pipe is arranged in the inner hole of the outer connecting steel pipe. During the construction process, structural glue is applied to the outer side of the expansion connection pipe, and a static pressure pile driver is used in conjunction with a pile driver to press the core pipe into the outer connecting steel pipe so that the expansion claws expand outward. The expanded expansion claws are pressed against the inner wall of the central through hole to form a fixed connection. At the same time, a reinforcement connector is welded or bolted between the outer side of the outer connecting steel pipe and the upper end face of the foundation pile section. The structural glue, the expansion claws and the reinforcement connector constitute a triple connection structure, which improves the connection strength between the bottom plate section and the pipe pile, and makes the column pile body connection node strength higher. In addition, the press-in expansion connection structure is adopted, which has the advantages of simple structure, convenient manufacturing and convenient connection operation.

[0061] (3) In the method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention, the outer diameter of the outer pipe body is larger than the outer diameter of the expansion connecting pipe, and a limiting step that can cooperate with the upper end face of the foundation pile section is formed at the upper end of the expansion connecting pipe. During the static pressure pile driving process, the limiting step abuts against the upper end face of the foundation pile section to transmit the pile driving pressure, thereby ensuring the stability of the pile driving construction.

[0062] (4) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention adopts a sleeve connection structure for the bottom plate section. The bottom plate section includes a receiving steel pipe. The lower end of the receiving steel pipe is integrally provided with a coaxial outer sleeve and an inner sleeve through a conversion portion. The inner diameter of the outer sleeve is matched with the outer diameter of the pile end connection portion of the foundation pile section. The outer diameter of the inner sleeve is matched with the inner diameter of the central through hole of the foundation pile section. During the construction process, structural adhesive is applied to the outer side of the inner sleeve, and the conversion portion is fixedly connected to the pile end connection portion at the upper end of the foundation pile section by bolts. The outer sleeve is welded to the pile end connection portion. The inner and outer sleeves of the bottom plate section ensure the positioning accuracy of the bottom plate section and the prefabricated pipe piles, and a triple connection structure of structural adhesive, bolts and welding is adopted between the two to ensure the connection strength between the bottom plate section and the foundation pile section, thereby improving the shear resistance and fatigue resistance of the connection node.

[0063] (5) The method for constructing assembled prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention adopts a pull-out resistant connecting plug-in to connect the bottom plate section and the foundation pile section. The bottom plate section includes a steel casing, embedded rods, stirrups and concrete. Each embedded rod is extended to the bottom end face of the bottom plate section and is provided with a lower end connecting sleeve. Each lower end connecting sleeve is threadedly connected with a connecting plug-in rod. The upper end of the foundation pile section is circumferentially distributed with corresponding embedded pipe pile pull rods. The embedded pipe pile pull rods are extended to the upper end face of the foundation pile section and are provided with an upper end connecting sleeve. The upper end connecting sleeve is provided with a spring, a washer, a locking plate and a nut sleeve in sequence from bottom to top. During the construction process, the bottom plate section is hoisted to the top of the foundation pile section, so that the connecting plug-in rod on the lower end face of the bottom plate section is aligned with the nut sleeve on the foundation pile section and connected with each other. The locking plate is used to lock the cone at the lower end of the connecting plug-in rod to achieve a fixed connection between the bottom plate section and the foundation pile section. The construction operation is simple and convenient, and the connection is firm and reliable.

[0064] (6) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention enters the support removal and recovery stage after the main structure construction in the foundation pit is completed. In the support removal and recovery step, the support beams and support sections are removed layer by layer from top to bottom, and the column sections are removed and recovered. The repaired column sections are designed and reused according to the design requirements of the next project, which effectively reduces the project cost.

[0065] (7) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention comprises: in the column section, a plurality of reinforcing ribs are circumferentially distributed on the inner wall of the thin-walled steel pipe, and the end reinforcing joints are respectively welded and fixed to the thin-walled steel pipe and the reinforcing ribs. The reinforcing ribs can improve the structural strength of the thin-walled steel pipe, and can effectively reduce the wall thickness of the steel pipe and reduce the amount of steel used; the reinforcing skeleton comprises a steel cage and an FRP fiber grid which are located on the inner side of the thin-walled steel pipe and arranged in layers, and the steel cage and the FRP fiber grid form two structural layers to improve the strength and toughness of the column section, which greatly improves the compressive and tensile strength of the thin-walled steel pipe, and takes into account the strength and weight of the column section.

[0066] (8) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention has a through hole coaxial with the thin-walled steel pipe at the center of the high-strength concrete layer. The high-strength concrete layer is cast by regenerated aerated high-strength concrete mixed with polypropylene fiber, which achieves lightweight while ensuring the strength and toughness of the pile body, making the construction simpler and safer.

[0067] (9) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention has a sensor installation hole reserved in the high-strength concrete layer for installing foundation pit section monitoring sensors and wireless communication modules, which is convenient for installing intelligent monitoring sensor equipment in the column piles. The wireless communication module communicates with the background monitoring system to provide data support for intelligent construction, which is beneficial to the intelligent control of foundation pit deformation. Moreover, since the column sections can be recycled, the sensors and monitoring systems can also be reused, reducing the cost of equipment use.

[0068] (10) The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention adopts a clamp used in conjunction with a static pressure pile driver to hold and press the column section when the outer diameter of the foundation pile section is larger than the outer diameter of the column section. The clamp is used to eliminate the diameter difference between the pipe pile and the steel pipe pile, and the static pressure pile driver can be used to continuously perform the pressing operation, thereby overcoming the defect of the traditional process that it takes a long time to replace the pile driver accessories when the diameter of the pipe pile and the upper section of the column pile are inconsistent, thereby further improving the construction efficiency of the column pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a flowchart of the steps of the construction method of the assembled prefabricated steel pipe-pile composite high-strength and toughness column pile according to Example 1 of the present invention;

[0070] Figure 2 A schematic diagram of a support structure of a column pile manufactured by the construction method of Example 1 of the present invention;

[0071] Figure 3 Schematic diagram of the structure of the foundation pile segment (prefabricated pipe pile) in Example 1 of the present invention;

[0072] Figure 4 It is a front view structural schematic diagram of the bottom plate section in Example 1 of the present invention;

[0073] Figure 5 Schematic diagram of the cross-sectional structure of the bottom plate segment in Example 1 of the present invention (unexpanded state);

[0074] Figure 6 Schematic diagram of the cross-sectional structure of the bottom plate segment in Example 1 of the present invention (expanded state);

[0075] Figure 7 This is a cross-sectional structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 1 of the present invention (unexpanded connection state);

[0076] Figure 8 This is a cross-sectional structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 1 of the present invention (expanded connection state);

[0077] Fig. 9 This is a schematic diagram of the structure of the reinforcement connector in Example 1 of the present invention;

[0078] Fig.10 This is a schematic diagram of the structure of installing a water stop plate and bolts on the bottom plate section in Example 1 of the present invention;

[0079] Fig.11 It is a front view structural schematic diagram of the column section in the present invention;

[0080] Fig.12 It is a schematic cross-sectional structure diagram of a column section in the present invention;

[0081] Fig.13 for Fig.12 Schematic diagram of the local enlarged structure at K in the middle;

[0082] Fig.14 This is a schematic diagram of the structure of the column section in the present invention;

[0083] Fig.15 It is a structural schematic diagram of the support section in the present invention;

[0084] Fig.16 It is a schematic cross-sectional structure diagram of the support section in the present invention;

[0085] Fig.17 It is a schematic diagram of the structure of installing bolts and connecting support plates in the support section of the present invention;

[0086] Fig.18 It is a structural schematic diagram of the connecting support plate in the present invention;

[0087] Fig.19 It is a schematic diagram of static pressure piling by means of a clamp in the present invention;

[0088] Fig. 20 It is a structural schematic diagram of the clamp in the present invention;

[0089] Fig.21 This is a flowchart of the steps of the construction method of the assembled prefabricated steel pipe-pile composite high-strength and toughness column pile according to Example 2 of the present invention;

[0090] Fig. 22 A schematic diagram of a support structure of a column pile manufactured by the construction method of Example 2 of the present invention;

[0091] Fig.23 It is a schematic diagram of the three-dimensional structure of the bottom plate segment in Example 2 of the present invention;

[0092] Fig.24 is a schematic cross-sectional structural diagram of a bottom plate segment in Example 2 of the present invention;

[0093] Fig.25 This is a front view structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 2 of the present invention;

[0094] Fig.26 It is a cross-sectional structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 2 of the present invention;

[0095] Fig. 27 A schematic diagram of a support structure of a column pile manufactured by the construction method of Example 3 of the present invention;

[0096] Fig.28 This is a front view structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 3 of the present invention;

[0097] Fig.29 It is a cross-sectional structural schematic diagram of the bottom plate segment installed on the foundation pile segment in Example 3 of the present invention;

[0098] Fig.30 for Fig.29 Schematic diagram of the local enlarged structure at M in the middle.

[0099] Explanation of the symbols in the schematic diagram:

[0100] 1. Foundation pile section; 1a. Center through hole; 1-1. Pipe pile body; 1-2. Pile end connection part; 1-3. Pipe pile embedded tie rod; 1-3-1. Upper end connection sleeve; 1-3-2. Spring; 1-3-3. Washer; 1-3-4. Locking plate; 1-3-5. Nut sleeve;

[0101] 2. Bottom plate section; 2-1. External connecting steel pipe; 2-1-1. External pipe body; 2-1-1a. Position limiting step; 2-1-2. Upper connecting part; 2-1-3. Expansion connecting pipe; 2-1-3a. Opening; 2-1-3b. Expansion claw; 2-1-3c. Inverted cone; 2-2. Core pipe; 2-2-1. Core pipe pushing part; 2-3. Reinforcement connector; 2-4. Water stop plate; 2-5. Bottom plate section bolts; 2-6. Received steel pipe; 2-6-1. Outer sleeve; 2-6-2. Inner sleeve; 2-6-3. Column connecting part; 2-6-4. Bolt hole; 2-6-5. Conversion part; 2-7. Steel casing; 2-8. Embedded rod; 2-8-1. Lower end connecting sleeve; 2-8-2. Connecting plug rod; 2-9. Stirrups; 2-10. Concrete;

[0102] 3. Column section; 3-1. Middle pile body; 3-1-1. Thin-walled steel pipe; 3-1-2. Reinforcement ribs; 3-1-3. Steel cage; 3-1-4. FRP fiber grid; 3-1-5. High-strength concrete layer; 3-1-6. Sensor installation hole; 3-2. End reinforcement joint; 3-2a. First pin hole;

[0103] 4. Support section; 4-1. Support steel pipe; 4-2. Pipe end connection portion; 4-2a. Second pin hole; 4-3. Support section bolt; 4-4. Connecting support plate; 4-4-1. Support plate body; 4-4-2. Support plate;

[0104] 5. Clamp; 5-1. Clamping plate;

[0105] 10. Base; 20. Foundation pit bottom plate; 30. Support beam. DETAILED DESCRIPTION

[0106] In the construction of deep foundation pit support, column piles have the following technical development trends and technical problems to be solved:

[0107] (I) High strength and high toughness requirements

[0108] Under complex geological conditions, column piles need to have compression resistance, bending resistance and impact resistance to avoid brittle failure. However, in the existing technology, it is difficult to balance the high strength and high toughness of column piles, especially in deep foundation pits and complex geological environments, where traditional materials and structural forms can no longer meet engineering requirements.

[0109] 2. Recyclability and economy

[0110] Most traditional column piles cannot be recycled, which not only causes material waste but also increases project costs. Although some recycling technologies have made certain progress, their recycling process is complex, the operation is difficult, and the adaptability is not high, making it difficult to be widely used in actual projects.

[0111] (III) Optimization of connection nodes

[0112] The foundation section of the column pile is usually made of cast-in-place piles or pipe piles. The insufficient strength of the connection nodes has always been a key problem restricting its performance improvement. In the prior art, the connection between the pile sections is mostly made of mechanical connectors, which has the risk of stress concentration and affects the long-term stability of the column pile.

[0113] (IV) Intelligent construction and monitoring

[0114] Although the application of intelligent monitoring technology in column piles is gradually increasing, its system integration cost is high, and the reuse and maintenance costs of sensors cannot be ignored. In addition, in the existing technology, the integration of intelligent construction and monitoring systems is low, making it difficult to achieve full automation and intelligent control of the construction process.

[0115] In summary, traditional column pile technology has many problems in terms of construction cycle, material recyclability, connection stiffness, environmental impact and intelligent construction. Although the existing improved technology has made some progress, it still cannot fully meet the needs of modern engineering construction for high efficiency, environmental protection, economy and sustainable development. Therefore, the development of an assembled column pile and its construction method with high strength, high toughness, recyclability, connection reliability and intelligent construction has become a technical problem that needs to be solved urgently, and it is also a key direction to promote technological progress in the field of foundation pit support engineering.

[0116] The present invention will be further described below in conjunction with the embodiments.

[0117] [Example 1]

[0118] Combination Figures 1 to 18 As shown, an assembled prefabricated steel pipe-pile composite high-strength toughness column pile construction method of the present embodiment, the column pile used in the construction method includes a foundation pile section 1, a bottom plate section 2, a column section 3 and a support section 4, the foundation pile section 1 is a prefabricated pipe pile; the column section 3 is a prefabricated steel pipe pile, including a middle pile body 3-1 and end reinforcement joints 3-2 fixed at both ends of the middle pile body 3-1, the outer side of the middle pile body 3-1 is a thin-walled steel pipe 3-1-1, the thin-walled steel pipe 3-1-1 has a high-strength concrete layer 3-1-5, and the high-strength concrete layer 3-1-5 has a reinforcement skeleton; the support section 4 includes a support steel pipe 4-1, and the two ends of the support steel pipe 4-1 have pipe end connection parts 4-2; the upper end of the foundation pile section 1 is connected to the lower end of the column section 3 located at the bottom through the bottom plate section 2, and the upper and lower adjacent column sections 3 are connected through the support section 4. The foundation pile section 1, the bottom plate section 2, the column section 3 and the support section 4 are all designed and prefabricated according to the engineering drawings and relevant information. Only assembly and pile driving operations are required at the construction site, which shortens the construction period.

[0119] Reference Figure 1 As shown, the construction method comprises the following steps:

[0120] S1. Construction of foundation pile section 1: First, clean and level the construction site to ensure the flatness and stability of the construction site, and lay out the construction position of the column piles. The layout accuracy should be controlled within the allowable range; Figure 1 As shown in (a), a static pile driver is used to press the foundation pile segment 1 into the designed elevation. During the pile pressing process, the pile pressing speed is controlled at 0.5 to 1.0 m / min to avoid damage or deflection of the column pile due to excessively fast pile pressing speed.

[0121] S2, bottom plate section 2 construction: Figure 1 As shown in (b) and (c), apply structural adhesive to the corresponding position of the bottom plate segment 2 to ensure that the structural adhesive is evenly distributed without bubbles and hollows; hoist the bottom plate segment 2 to the top of the foundation pile segment 1, and reinforce and fix the bottom plate segment 2 and the foundation pile segment 1;

[0122] S3, column section 3 and support section 4 construction: Figure 1 (d) to (f), select the appropriate pile driving process according to the depth of the foundation pit. For a shallow foundation pit, first, each section of the column segment 3 is connected by socket fitting through the support segment 4 and assembled by pins or bolts, then hoisted as a whole and socket fitting with the bottom plate segment 2 and assembled by pins or bolts, and a static pile driver is used to hold and press the piles at one time, and finally the pile driver is used to press the column pile body to the designed elevation; for a deep foundation pit, the column segment 3 and the support segment 4 are installed section by section, and then a static pile driver is used to hold and press the piles in sections. , and finally cooperate with the pile driver to press the column pile body to the designed elevation, wherein the first column section 3 is socket-fitted with the bottom plate section 2 and assembled and connected by pins or bolts, and the remaining column sections 3 are socket-fitted with the support section 4 and assembled and connected by pins or bolts; generally speaking, the static pile driver is used to press the top elevation of the column pile body to about 1m from the ground, and then the pile driver is installed, and the column pile body is sent to the designed elevation by the pile driver. The holding pressure and holding speed should also be controlled during the holding process to ensure the verticality and stability of the pile body;

[0123] S4, foundation pit excavation and support construction: after the column piles are planted at the designed elevation, the foundation pit soil is excavated layer by layer, and the support beams 30 are installed layer by layer from top to bottom; Figure 1 (g) and Figure 2 As shown, when the support beam 30 is connected to the support segment 4, firstly, a connecting support plate 4-4 and a plurality of supporting segment studs 4-3 are welded on the supporting segment 4, the connecting support plate 4-4 is located at the lower end of the supporting steel pipe 4-1, and the supporting segment studs 4-3 are distributed on the outer periphery of the supporting steel pipe 4-1, and then the support beam 30 is connected to the supporting segment 4 by cast-in-place; Fig.17 and Fig.18As shown, the connecting support plate 4-4 includes a support plate body 4-4-1 and a plurality of support plates 4-4-2 distributed on the inner side of the support plate body 4-4-1, the support plates 4-4-2 are welded to the support plate body 4-4-1, and the support plate body 4-4-1 is welded to the lower part of the support steel pipe 4-1 for the second time after the foundation pit is excavated, and the support plates 4-4-2 are distributed on the outer periphery of the column section 3. The use of the connecting support plate 4-4 further facilitates the connection between the support section 4 and the support beam 30, which can facilitate the cast-in-place construction of the support beam 30; at the same time, the support plates 4-4-2 of the connecting support plate 4-4 can form a supporting effect on the column section 3, further ensuring the connection stability between the support section 4 and the column section 3; since the connecting support plate 4-4 is a secondary welding construction, in order to facilitate its arrangement on the outer side of the support steel pipe 4-1, the connecting support plate 4-4 can be designed as two semicircular components. During the welding construction, the two semicircular components are embraced on the support steel pipe 4-1 for welding and fixing;

[0124] S5, foundation pit bottom plate 20 and main structure construction: Figure 2 As shown, after the foundation pit soil is excavated to the base 10, the bottom plate section 2 is exposed, and the foundation pile section 1 is located in the stratum of the base 10. First, a water stop plate 2-4 and a plurality of bottom plate section studs 2-5 are welded on the outer periphery of the bottom plate section 2 (refer to Fig.10 As shown), the foundation pit floor 20 and the main structure are then constructed, and the floor section 2 is cast in situ with the foundation pit floor 20. Similar to the above-mentioned connecting support plate 4-4, since the water stop plate 2-4 is a secondary welding construction, in order to facilitate its installation outside the floor section 2, the water stop plate 2-4 can also be designed as two water stop semicircular rings. When installing the water stop plate 2-4, the two water stop semicircular rings are welded and fixed on the floor section 2.

[0125] The above-mentioned assembled prefabricated steel pipe-pile composite high-strength and toughness column pile construction method, the column pile consists of a foundation pile section, a bottom plate section, a column section and a support section, wherein the foundation pile section is a prefabricated pipe pile, and the column section is a prefabricated steel pipe pile. By improving the steel-concrete composite structure of the prefabricated steel pipe pile, the pile body strength and toughness of the column pile are improved, and the structural strength of the column section is improved. The static pressure pile driver can be used for holding and pressure construction, and the construction efficiency of the column pile is greatly improved by optimizing the construction sequence; and the column section is assembled with a socket structure, which can be 100% recycled, reducing construction costs and significantly improving the economy of the column pile.

[0126] like Figure 3 As shown, the foundation pile section 1 in this embodiment is a prefabricated pipe pile similar to an existing pipe pile, and the two ends of the pipe pile body 1-1 are provided with pile end connecting parts 1-2, and the pile end connecting parts 1-2 are metal plate assemblies, and the pipe pile body 1-1 has a central through hole 1a that runs vertically. Figures 4 to 8As shown, the above-mentioned bottom plate section 2 adopts a press-in expansion connection structure, including an external connecting steel pipe 2-1 and a core pipe 2-2. The upper end of the outer tube body 2-1-1 of the external connecting steel pipe 2-1 is provided with an upper connecting part 2-1-2 for assembling and connecting with the end reinforcement joint 3-2 of the column section 3. The upper connecting part 2-1-2 is specifically a socket structure, and a plurality of pin holes are distributed around the upper connecting part 2-1-2. The end reinforcement joint 3-2 is specifically a socket joint, and a plurality of first pin holes 3-2a are distributed around it. During installation, the socket joint of the end reinforcement joint 3-2 is inserted into the socket of the upper connecting part 2-1-2, and the pin holes of the two are made to correspond one to one, and are connected by pins or bolts to achieve a firm connection between the external connecting steel pipe 2-1 and the column section 3. The lower end of the outer tube body 2-1-1 is provided with an expansion connection tube 2-1-3 that can be inserted into the central through hole 1a of the foundation pile segment 1. The tube wall of the expansion connection tube 2-1-3 is provided with a plurality of openings 2-1-3a, and expansion claws 2-1-3b are formed between adjacent openings 2-1-3a. The inner side wall of the expansion claw 2-1-3b is an inverted cone surface 2-1-3c; the core tube 2-2 is arranged in the inner hole of the outer connecting steel tube 2-1, and the upper end of the core tube 2-2 has a core tube pushing portion 2-2-1; the construction of the bottom plate segment 2 in the above step S2 includes the following sub-steps:

[0127] S2-1, such as Figure 1 As shown in (b), the structural adhesive is applied to the outer side of the expansion connection pipe 2-1-3, and the external connection steel pipe 2-1 is hoisted and installed on the top of the foundation pile segment 1, so that the expansion connection pipe 2-1-3 is inserted into the central through hole 1a of the foundation pile segment 1; the structural adhesive preferably adopts high-strength polyurea structural adhesive, which realizes the first fixed connection between the bottom plate segment 2 and the foundation pile segment 1 after curing, and the structural adhesive also has a sealing and waterproofing effect;

[0128] S2-2, put the core tube 2-2 into the inner hole of the external connecting steel tube 2-1, as shown in Figure 1 As shown in (c), the core tube 2-2 is pressed into the outer connecting steel pipe 2-1 by using a static pile driver in conjunction with a pile driver. The lower end of the core tube 2-2 can move to the expansion claw 2-1-3b under the downward push and cooperate with the inverted cone surface 2-1-3c to expand the expansion claw 2-1-3b outward. The expanded expansion claw 2-1-3b is pressed against the inner wall of the central through hole 1a to form a fixed connection; Figure 7 As shown, the expansion connection pipe 2-1-3 in the unexpanded state is in clearance fit with the central through hole 1a, and the expansion deformation amplitude of the expansion claw 2-1-3b is greater than the fitting clearance between the two. When the core pipe 2-2 is pressed down, the lower end of the core pipe 2-2 presses the expansion claw 2-1-3b to expand outward and press against the inner wall of the central through hole 1a, forming a firm expansion connection (such as Figure 8 As shown), the core tube 2-2 will not retreat under the action of friction resistance, so it will not cause the expansion claw 2-1-3b to shrink and loosen, forming a second fixed connection;

[0129] S2-3, welding or bolting the reinforcing connector 2-3 between the outer side of the external connecting steel pipe 2-1 and the upper end surface of the foundation pile segment 1 to form a third fixed connection; Fig. 9 As shown, the above-mentioned reinforcement connector 2-3 is an annular steel member with an "L"-shaped cross-section. The reinforcement connector 2-3 can be welded to the external connecting steel pipe 2-1, and the reinforcement connector 2-3 is welded or bolted to the pile end connection part 1-2 at the upper end of the foundation pile segment 1.

[0130] By adopting the above-mentioned design of the bottom plate section 2, the structural adhesive, the expansion claws 2-1-3b and the reinforcement connector 2-3 form a triple connection structure, which improves the connection strength between the bottom plate section 2 and the pipe pile, makes the connection node strength of the column pile body higher, and the press-in expansion connection structure has the advantages of simple structure, easy production and convenient connection operation.

[0131] like Figures 4 to 6 As shown, in this embodiment, the outer diameter of the outer tube body 2-1-1 is larger than the outer diameter of the expansion connecting tube 2-1-3, and a limiting step 2-1-1a that can cooperate with the upper end surface of the foundation pile segment 1 is formed at the upper end of the expansion connecting tube 2-1-3. During the static pressure pile driving process, the limiting step 2-1-1a abuts against the upper end surface of the foundation pile segment 1 to transmit the pile driving pressure, thereby ensuring the stability of the pile driving construction.

[0132] After the construction of step S5 is completed, the support removal and recovery step S6 is entered; in the support removal and recovery step S6, since the two ends of the column segment 3 adopt a socket fit, the support beam 30 and the support segment 4 are removed layer by layer from top to bottom, and the column segment 3 is removed and recovered. The repaired column segment 3 is designed and reused according to the design requirements of the next project, which effectively reduces the project cost. Specifically, after removing the upper support beam 30 and the support segment 4, the lower section of the column segment 3 can be dismantled without loss for easy recycling. During the dismantling process, special dismantling tools should be used to avoid damage to the column segment 3. The bottom plate segment 2 and the foundation pile segment 1 are left inside the foundation pit as permanent components.

[0133] Reference Figures 11 to 14As shown, in the column section 3, a plurality of reinforcing ribs 3-1-2 are circumferentially distributed on the inner wall of the thin-walled steel pipe 3-1-1, and the reinforcing ribs 3-1-2 are welded to the inner wall of the thin-walled steel pipe 3-1-1. The reinforcing ribs 3-1-2 can improve the structural strength of the thin-walled steel pipe 3-1-1, and can effectively reduce the wall thickness of the steel pipe and reduce the amount of steel used. The end reinforcing joint 3-2 is welded and fixed to the thin-walled steel pipe 3-1-1 and the reinforcing ribs 3-1-2 respectively. The end reinforcing joint 3-2 can be a cylinder sleeve structure, which is firmly and reliably welded to the thin-walled steel pipe 3-1-1 and the reinforcing ribs 3-1-2. The reinforcement skeleton includes a steel cage 3-1-3 and an FRP fiber grid 3-1-4 which are located inside the thin-walled steel pipe 3-1-1 and arranged in layers. The steel cage 3-1-3 can be arranged on the outside of the FRP fiber grid 3-1-4 or on the inside of the FRP fiber grid 3-1-4. The steel cage 3-1-3 and the FRP fiber grid 3-1-4 form two structural layers to improve the strength and toughness of the column section 3, which greatly improves the compressive and tensile strength of the thin-walled steel pipe 3-1-1 and takes into account the strength and weight of the column section. The steel bars used in the steel cage 3-1-3 should have good welding performance and corrosion resistance to ensure the long-term stability of the column pile; the FRP fiber grid 3-1-4 has good tensile strength and corrosion resistance, which can effectively improve the toughness of the column pile; in order to ensure the close combination of the FRP fiber grid 3-1-4 and the steel cage 3-1-3, it is necessary to set a special connector between the fiber grid and the steel cage. The connector can be a metal tie or a special fiber reinforced plastic tie to fix the fiber grid on the steel cage; when fixing, the spacing of the connectors should be uniform, usually not more than 300mm, to ensure that the fiber grid does not shift during the concrete pouring process. In addition, the center of the high-strength concrete layer 3-1-5 has a through hole coaxial with the thin-walled steel pipe 3-1-1, forming a tubular structure with a cavity. The high-strength concrete layer 3-1-5 is cast by recycled aerated high-strength concrete mixed with polypropylene fiber, which achieves lightweight while ensuring the strength and toughness of the pile body, making the construction simpler and safer. The dosage of polypropylene fiber should be adjusted according to design requirements, usually 0.1% to 0.2% of the concrete volume.

[0134] like Fig.12 and Fig.13 As shown, the high-strength concrete layer 3-1-5 is also reserved with a sensor installation hole 3-1-6 for installing a foundation pit section monitoring sensor and a wireless communication module, which is convenient for installing intelligent monitoring sensor equipment in the column pile, and communicating with the background monitoring system through the wireless communication module to provide data support for intelligent construction, which is conducive to intelligent control of foundation pit deformation; and because the column section 3 can be recycled, the sensor and monitoring system can also be reused, reducing the cost of equipment use. The foundation pit section monitoring sensor can use sensors such as stress monitors, displacement monitors, and axial force detectors.

[0135] like Fig.15 and Fig.16 As shown, the support section 4 in this embodiment is a steel sleeve structure, and its two ends are respectively provided with pipe end connection parts 4-2 which are also a socket structure. A second pin hole 4-2a is provided around the pipe end connection part 4-2. During installation, the socket joint of the end reinforcement joint 3-2 is inserted into the socket of the pipe end connection part 4-2, and the pin holes of the two are made to correspond one to one, and pins are used for connection to achieve a firm connection between the support section 4 and the column section 3.

[0136] like Fig.19 As shown, in the above step S3, when the outer diameter of the foundation pile segment 1 is larger than the outer diameter of the column segment 3, the clamp 5 used in conjunction with the static pile driver is used to hold and press the column segment 3. Fig. 20 As shown, the clamp 5 is composed of more than two clamping plates 5-1, for example, four clamping plates 5-1 are used to form the clamp 5, and the upper and lower ends of the clamping plates 5-1 are provided with convex edges extending outward, which facilitate the installation of each clamping plate 5-1 on the static press machine, and the outer diameter of the clamp 5 engaged on the column section 3 is equivalent to the outer diameter of the foundation pile section 1; when the column section 3 is constructed, the clamp 5 is installed on the static pile driver, and the static pile driver holds the column section 3 through the clamp 5 to perform pile pressing operation. The use of the clamp 5 eliminates the diameter difference between the pipe pile and the steel pipe pile, and the static pile driver can be used to continuously perform the pressing operation, which overcomes the defect of the traditional process that it takes a long time to replace the pile driver accessories when the diameter of the pipe pile and the upper section of the column pile is inconsistent, and further improves the construction efficiency of the column pile.

[0137] [Example 2]

[0138] The present embodiment is a method for constructing a prefabricated steel pipe-pile composite high-strength and toughness column pile, the basic structure and working principle of which are the same as those of the first embodiment, except that:

[0139] like Figure 21 to Figure 26As shown, in this embodiment, the above-mentioned bottom plate section 2 adopts a sleeve connection structure, and the bottom plate section 2 includes a receiving steel pipe 2-6. The upper end of the receiving steel pipe 2-6 is provided with a column connecting part 2-6-3 for assembling and connecting with the end reinforcement joint 3-2 of the column section 3. The column connecting part 2-6-3 is a socket, and a plurality of pin holes are provided around it. The end reinforcement joint 3-2 of the column section 3 is inserted into the column connecting part 2-6-3 so that the pin holes of the two are opposite to each other, and they can be connected by pins or bolts. The lower end of the receiving steel pipe 2-6 is integrally provided with a coaxial outer sleeve 2-6-1 and an inner sleeve 2-6-2 through a conversion portion 2-6-5. The inner diameter of the outer sleeve 2-6-1 is adapted to the outer diameter of the pile end connection portion 1-2 of the foundation pile segment 1, and the outer diameter of the inner sleeve 2-6-2 is adapted to the inner diameter of the central through hole 1a of the foundation pile segment 1. The length of the inner sleeve 2-6-2 is preferably greater than the length of the outer sleeve 2-6-1, so as to facilitate accurate alignment during assembly; the height of the pile end connection portion 1-2 at the upper end of the foundation pile segment 1 is greater than the height of the outer sleeve 2-6-1, and bolt holes 2-6-4 for bolt connection with the pile end connection portion 1-2 at the upper end of the foundation pile segment 1 are also provided around the conversion portion 2-6-5; the construction of the bottom plate segment 2 in the above step S2 includes the following sub-steps:

[0140] S2-1, apply structural glue on the outside of the inner sleeve 2-6-2, and hoist the receiving steel pipe 2-6 to the top of the foundation pile segment 1, so that the inner sleeve 2-6-2 is inserted into the central through hole 1a of the foundation pile segment 1, and the outer sleeve 2-6-1 is sleeved on the outside of the pile end connection part 1-2 at the upper end of the foundation pile segment 1; the structural glue preferably adopts high-strength polyurea structural glue, and after curing, the first fixed connection between the bottom plate segment 2 and the foundation pile segment 1 is achieved;

[0141] S2-2, using bolts to fix the conversion part 2-6-5 to the pile end connection part 1-2 at the upper end of the foundation pile segment 1, with multiple bolts evenly distributed around the circumference of the bottom plate segment 2 to form a second fixed connection;

[0142] S2-3, welding the outer sleeve 2-6-1 to the pile end connection part 1-2. Since the height of the pile end connection part 1-2 at the upper end of the foundation pile segment 1 is greater than the height of the outer sleeve 2-6-1, the welding operation can be conveniently performed from the outside to form a third fixed connection.

[0143] The above-mentioned sleeve-type bottom plate section 2 is adopted, and its inner and outer sleeves ensure the positioning accuracy of the bottom plate section 2 and the prefabricated pipe piles, and a triple connection structure of structural adhesive, bolts and welding is adopted between the two to ensure the connection strength between the bottom plate section 2 and the foundation pile section 1, and improve the shear resistance and fatigue resistance of the connection node.

[0144] [Example 3]

[0145] The present embodiment is a method for constructing a prefabricated steel pipe-pile composite high-strength and toughness column pile, the basic structure and working principle of which are the same as those of the first embodiment, except that:

[0146] like Figures 27 to 30 As shown, in this embodiment, the bottom plate section 2 and the foundation pile section 1 are connected by an anti-pullout connection plug. Specifically, the bottom plate section 2 includes a steel casing 2-7, an embedded rod 2-8, stirrups 2-9 and concrete 2-10. The embedded rods 2-8 are circumferentially distributed around the steel casing 2-7, and each embedded rod 2-8 is extended to the bottom end surface of the bottom plate section 2 and is provided with a lower end connection sleeve 2-8-1. Each lower end connection sleeve 2-8-1 is internally threadedly connected with a connecting plug rod 2-8-2. Each embedded rod 2-8 is connected by stirrups 2-9, and the steel casing 2-7 is filled with concrete 2-10. A column connection socket is reserved at the upper end of the steel casing 2-7, and a plurality of pin holes are arranged around it. The end reinforcement joint 3-2 of the column section 3 is inserted into the column connection socket so that the pin holes of the two are opposite to each other, and can be connected by pins or bolts. The upper end of the foundation pile segment 1 is circumferentially distributed with corresponding pre-embedded pipe pile tie rods 1-3, and the pre-embedded pipe pile tie rods 1-3 extend to the upper end surface of the foundation pile segment 1 and are provided with an upper end connecting sleeve 1-3-1, and the upper end connecting sleeve 1-3-1 is provided with a spring 1-3-2, a washer 1-3-3, a locking plate 1-3-4 and a nut sleeve 1-3-5 from bottom to top, the upper end of the spring 1-3-2 abuts against the washer 1-3-3, the locking plate 1-3-4 is located above the washer 1-3-3, and the locking plate 1-3-4 and the lower end of the nut sleeve 1-3-5 adopt an inverted cone structure, and the nut sleeve 1-3-5 is threadedly fixed to the upper end of the upper end connecting sleeve 1-3-1.

[0147] During the construction of the bottom plate segment 2 in the above step S2, the bottom plate segment 2 is hoisted to the top of the foundation pile segment 1, so that the connecting rod 2-8-2 on the lower end surface of the bottom plate segment 2 is aligned with the nut sleeve 1-3-5 on the foundation pile segment 1 and connected by plugging, and the cone at the lower end of the connecting rod 2-8-2 is locked by the locking plate 1-3-4 to achieve a fixed connection between the bottom plate segment 2 and the foundation pile segment 1. When the connecting rod 2-8-2 is inserted into the nut sleeve 1-3-5, the lower end of the connecting rod 2-8-2 is a cone. When the lower end of the cone contacts the locking plate 1-3-4, it pushes it downward, forcing the spring 1-3-2 to compress, and the locking plate 1-3-4 gradually separates outward, so that the cone passes through the locking plate 1-3-4. At this time, the locking plate 1-3-4 moves upward under the action of the spring 1-3-2, and the locking plate 1-3-4 contracts and clamps the cone of the connecting rod 2-8-2 through the inverted cone structure, thereby realizing the connection between the bottom plate section 2 and the foundation pile section 1, and the construction operation is simple and convenient. The above-mentioned pull-out resistant connecting plug is preferably evenly distributed in 8 groups around the pile body, so that the connection is more stable and the connection force is more balanced.

[0148] The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles of the present invention combines the advantages of prefabricated pipe piles and steel pipe piles, and achieves the unity of high strength, high toughness, recyclability and economy through innovative structural design and connection methods. It has the following beneficial effects:

[0149] 1) Each pile section of the column pile adopts a prefabricated structure, which does not require on-site pouring, making the construction simpler; and the bottom plate section adopts a steel pipe structure, which is fixedly connected to the foundation pile section and remains in the bottom stratum of the foundation pit as a permanent part. The column section, the bottom plate section and the support section are all connected by socket fitting and assembled by pins or bolts. The overall connection strength of the column pile is higher, the shear resistance and fatigue resistance of the connection node are better, and the column section can be 100% recycled, which can effectively reduce the project cost;

[0150] 2) The column section includes a middle pile body and end reinforcement joints fixed at both ends of the middle pile body. The outer side of the middle pile body is a thin-walled steel pipe, and a high-strength concrete layer is provided inside the thin-walled steel pipe. A reinforcement skeleton is provided inside the high-strength concrete layer. The steel-concrete composite structure is adopted, which can not only reduce the wall thickness of the steel pipe of the column section and reduce the amount of steel used, but also improve the pile body strength and toughness of the column pile, avoid brittle damage to the column section during construction, improve the structural strength of the column section, and can use a static pile driver for holding pressure construction. By optimizing the construction sequence, the construction efficiency of the column pile is greatly improved, and the economy of the column pile is significantly improved;

[0151] 3) The outer side of the bottom plate section is provided with a water stop plate and a number of bottom plate section bolts which are welded for the second time after the foundation pit is excavated, which can be used to connect with the bottom plate of the foundation pit. The outer side of the supporting steel pipe of the supporting section is provided with a connecting support plate and a number of supporting section bolts which are welded for the second time after the foundation pit is excavated, which can be used to connect with the supporting beam in the foundation pit, which can improve the connection firmness between the bottom plate of the foundation pit and the column pile, and between the supporting beam of the foundation pit and the column pile, and ensure the stability of the deep foundation pit support;

[0152] 4) The bottom plate section adopts three structural forms: press-in expansion connection, sleeve connection and pull-out connection plug-in, which not only improves the convenience of connection operation, but also can use multiple connections to improve the connection strength between the bottom plate section and the pile, greatly improving the shear resistance and fatigue resistance of the connection node;

[0153] 5) By improving the structure of the column section, the strength and weight of the column section are taken into account. The triple reinforcement design of reinforcing ribs, steel cage and FRP fiber grid is used to greatly improve the compressive and tensile strength of the thin-walled steel pipe. At the same time, the hollow column section pile body design is adopted. The high-strength concrete layer is cast by recycled aerated high-strength concrete mixed with polypropylene fiber, which realizes the lightweight of the column section;

[0154] 6) In terms of intelligence, by reserving sensor installation holes in the column section, foundation pit section monitoring sensors and wireless communication modules can be installed, and the wireless communication module can be connected to the background monitoring system to provide data support for intelligent construction, which is conducive to intelligent control of foundation pit deformation; and because the column section can be recycled, the sensor and monitoring system can also be reused, reducing the cost of equipment use;

[0155] 7) An innovative clamp is designed for use with a static pile driver. The clamp eliminates the diameter difference between the pipe pile and the steel pipe pile, and the static pile driver can be used for continuous pressing operations, overcoming the defect of the traditional process that it takes a long time to replace the pile driver accessories when the diameter of the pipe pile and the upper section of the column pile are inconsistent, further improving the construction efficiency of the column pile.

[0156] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. The construction method of prefabricated steel pipe-pile composite high-strength and toughness column piles is characterized by: The column pile used in the construction method comprises a foundation pile section (1), a bottom plate section (2), a column section (3) and a support section (4), wherein the foundation pile section (1) is a prefabricated pipe pile; the column section (3) is a prefabricated steel pipe pile, comprising a middle pile body (3-1) and end reinforcement joints (3-2) fixedly arranged at both ends of the middle pile body (3-1); the outer side of the middle pile body (3-1) is a thin-walled steel pipe (3-1-1), the thin-walled steel pipe (3-1-1) has a high-strength concrete layer (3-1-5), and the high-strength concrete layer (3-1-5) has a reinforcement skeleton; the support section (4) comprises a support steel pipe (4-1), and both ends of the support steel pipe (4-1) have pipe end connection parts (4-2); The construction method comprises the following steps: S1. Construction of foundation pile segment (1): Use a static pile driver to press the foundation pile segment (1) into the designed elevation. During the pile pressing process, the pile pressing speed is controlled at 0.5-1.0 m / min. S2, construction of the bottom plate segment (2): applying structural adhesive to the corresponding position of the bottom plate segment (2), hoisting and installing the bottom plate segment (2) on the top of the foundation pile segment (1), and reinforcing and fixing the bottom plate segment (2) and the foundation pile segment (1); S3, construction of column segments (3) and support segments (4): for shallow foundation pits, firstly, each section of the column segment (3) is connected by sockets and spigots through the support segment (4) and assembled and connected by pins or bolts, then hoisted as a whole and connected by sockets and spigots with the bottom plate segment (2) and assembled and connected by pins or bolts, and a static pile driver is used to hold and press the piles at one time, and finally, the pile body of the column pile is pressed to the designed elevation with the help of a pile driver; for deep foundation pits, the column segments (3) and support segments (4) are installed section by section, and then a static pile driver is used to hold and press the piles in sections, and finally, the pile body of the column pile is pressed to the designed elevation with the help of a pile driver, wherein the first section of the column segment (3) is connected by sockets and spigots with the bottom plate segment (2) and assembled and connected by pins or bolts, and the remaining column segments (3) are connected by sockets and spigots with the support segment (4) and assembled and connected by pins or bolts; S4, foundation pit excavation and support construction: excavating the foundation pit soil layer by layer, and installing the support beam (30) layer by layer from top to bottom; when connecting the support beam (30) to the support section (4), firstly, welding a connecting support plate (4-4) and a plurality of support section bolts (4-3) on the support section (4), the connecting support plate (4-4) is located at the lower end of the support steel pipe (4-1), and the support section bolts (4-3) are distributed on the outer periphery of the support steel pipe (4-1), and then the support beam (30) is connected to the support section (4) by cast-in-place; S5. Construction of foundation pit floor (20) and main structure: After excavating the foundation pit soil to the base (10), the floor section (2) is exposed, and the foundation pile section (1) is located in the stratum of the base (10). First, a water stop plate (2-4) and a plurality of floor section bolts (2-5) are welded on the periphery of the floor section (2), and then the foundation pit floor (20) and main structure are constructed, and the floor section (2) and the foundation pit floor (20) are connected together by cast-in-place.

2. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 1, characterized in that: The bottom plate section (2) adopts a press-in expansion connection structure, comprising an external connection steel pipe (2-1) and a core pipe (2-2); the upper end of the outer pipe body (2-1-1) of the external connection steel pipe (2-1) is provided with an upper connection part (2-1-2) for assembly and connection with the end reinforcement joint (3-2) of the column section (3); the lower end of the outer pipe body (2-1-1) is provided with an expansion connection pipe (2-1-2) capable of being inserted into the central through hole (1a) of the foundation pile section (1). -1-3), a plurality of openings (2-1-3a) are provided on the wall of the expansion connection pipe (2-1-3), expansion claws (2-1-3b) are formed between adjacent openings (2-1-3a), and the inner side wall of the expansion claws (2-1-3b) is an inverted cone surface (2-1-3c); the core pipe (2-2) is arranged in the inner hole of the external connection steel pipe (2-1), and the upper end of the core pipe (2-2) has a core pipe pushing portion (2-2-1); The construction of the bottom plate section (2) in step S2 above includes the following sub-steps: S2-1, applying structural adhesive to the outer side of the expansion connection pipe (2-1-3), and hoisting and installing the outer connection steel pipe (2-1) on the top of the foundation pile segment (1), so that the expansion connection pipe (2-1-3) is inserted into the central through hole (1a) of the foundation pile segment (1); S2-2, placing the core tube (2-2) into the inner hole of the outer connecting steel tube (2-1), using a static pile driver in conjunction with a pile driver to press the core tube (2-2) into the outer connecting steel tube (2-1) so that the expansion claws (2-1-3b) expand outward, and the expanded expansion claws (2-1-3b) press against the inner wall of the central through hole (1a) to form a fixed connection; S2-3, a reinforcement connector (2-3) is welded or bolted between the outer side of the external connection steel pipe (2-1) and the upper end surface of the foundation pile segment (1).

3. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 2 is characterized in that: The outer diameter of the outer tube body (2-1-1) is greater than the outer diameter of the expansion connecting tube (2-1-3), and a limiting step (2-1-1a) capable of matching with the upper end surface of the foundation pile segment (1) is formed at the upper end of the expansion connecting tube (2-1-3). During the static pressure piling process, the limiting step (2-1-1a) abuts against the upper end surface of the foundation pile segment (1) to transmit the pile pressure.

4. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 1, characterized in that: The bottom plate section (2) adopts a sleeve connection structure. The bottom plate section (2) includes a receiving steel pipe (2-6). The upper end of the receiving steel pipe (2-6) is provided with a column connection part (2-6-3) for assembly and connection with the end reinforcement joint (3-2) of the column section (3). The lower end of the receiving steel pipe (2-6) is integrally provided with a coaxial outer sleeve (2-6-1) and an inner sleeve (2-6-2) through a conversion part (2-6-5). The inner diameter of the outer sleeve (2-6-1) is The outer diameter of the inner sleeve (2-6-2) matches the outer diameter of the pile end connection part (1-2) of the foundation pile segment (1); the outer diameter of the inner sleeve (2-6-2) matches the inner diameter of the central through hole (1a) of the foundation pile segment (1); the height of the pile end connection part (1-2) at the upper end of the foundation pile segment (1) is greater than the height of the outer sleeve (2-6-1); and bolt holes (2-6-4) for bolt connection with the pile end connection part (1-2) at the upper end of the foundation pile segment (1) are provided around the conversion part (2-6-5); The construction of the bottom plate section (2) in step S2 above includes the following sub-steps: S2-1, applying structural adhesive to the outer side of the inner sleeve (2-6-2), and hoisting and installing the receiving steel pipe (2-6) on the top of the foundation pile segment (1), so that the inner sleeve (2-6-2) is inserted into the central through hole (1a) of the foundation pile segment (1), and the outer sleeve (2-6-1) is sleeved on the outer side of the pile end connection part (1-2) at the upper end of the foundation pile segment (1); S2-2, using bolts to fix the conversion part (2-6-5) to the pile end connection part (1-2) at the upper end of the foundation pile segment (1); S2-3, connecting the outer sleeve (2-6-1) to the pile end connection part (1-2) by welding.

5. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 1, characterized in that: The bottom plate section (2) and the foundation pile section (1) are connected by using an anti-pullout connection plug-in. The bottom plate section (2) comprises a steel casing (2-7), embedded rods (2-8), stirrups (2-9) and concrete (2-10). The embedded rods (2-8) are circumferentially distributed around the steel casing (2-7). Each embedded rod (2-8) is extended to the bottom end surface of the bottom plate section (2) and is provided with a lower end connection sleeve (2-8-1). Each lower end connection sleeve (2-8-1) is internally threadedly connected to a connection plug rod (2-8-2). Each embedded rod (2-8) is connected to each other by stirrups (2-9). The concrete (2-10) is filled in the steel casing (2-7). The upper end of the foundation pile section (1) is circumferentially distributed around the steel casing (2-7). Corresponding pre-buried tie rods (1-3) are distributed, and an upper end connecting sleeve (1-3-1) is provided at the upper end surface of the pre-buried tie rods (1-3) extending to the foundation pile section (1). A spring (1-3-2), a washer (1-3-3), a locking plate (1-3-4) and a nut sleeve (1-3-5) are sequentially provided in the upper end connecting sleeve (1-3-1) from bottom to top, the upper end of the spring (1-3-2) abuts against the washer (1-3-3), the locking plate (1-3-4) is located above the washer (1-3-3), and the locking plate (1-3-4) and the lower end of the nut sleeve (1-3-5) are matched with an inverted cone structure, and the nut sleeve (1-3-5) is threadedly fixed to the upper end of the upper end connecting sleeve (1-3-1); During the construction of the bottom plate segment (2) in the above step S2, the bottom plate segment (2) is hoisted to the top of the foundation pile segment (1), the connecting rod (2-8-2) on the lower end surface of the bottom plate segment (2) is aligned with the nut sleeve (1-3-5) on the foundation pile segment (1) and plugged into the connection, and the cone at the lower end of the connecting rod (2-8-2) is locked by using the locking plate (1-3-4), so as to realize the fixed connection between the bottom plate segment (2) and the foundation pile segment (1).

6. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to any one of claims 1 to 5, characterized in that: After the construction of step S5 is completed, the support dismantling and recycling step S6 is entered; in the support dismantling and recycling step S6, the support beams (30) and support sections (4) are dismantled layer by layer from top to bottom, and the column sections (3) are dismantled and recycled. The repaired column sections (3) are designed and reused according to the design requirements of the next project.

7. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 6, characterized in that: In the column section (3), a plurality of reinforcing ribs (3-1-2) are circumferentially distributed on the inner wall of the thin-walled steel pipe (3-1-1), and the end reinforcing joint (3-2) is welded and fixed to the thin-walled steel pipe (3-1-1) and the reinforcing ribs (3-1-2), respectively; the reinforcing skeleton comprises a steel cage (3-1-3) and an FRP fiber grid (3-1-4) which are located on the inner side of the thin-walled steel pipe (3-1-1) and arranged in layers.

8. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 7, characterized in that: The center of the high-strength concrete layer (3-1-5) is provided with a through hole coaxial with the thin-walled steel pipe (3-1-1), and the high-strength concrete layer (3-1-5) is cast by regenerated aerated high-strength concrete mixed with polypropylene fibers.

9. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 7, characterized in that: The high-strength concrete layer (3-1-5) is also provided with a sensor installation hole (3-1-6) for installing a foundation pit section monitoring sensor and a wireless communication module.

10. The method for constructing prefabricated steel pipe-pile composite high-strength and toughness column piles according to claim 6, characterized in that: In step S3, in the case where the outer diameter of the foundation pile segment (1) is larger than the outer diameter of the column segment (3), a clamp (5) used in conjunction with a static pile driver is used to hold and press the column segment (3), wherein the clamp (5) is composed of two or more clamping plates (5-1), and the upper and lower ends of the clamping plates (5-1) are provided with convex edges extending outward, and the outer diameter of the clamp (5) held on the column segment (3) is equivalent to the outer diameter of the foundation pile segment (1); when the column segment (3) is constructed, the clamp (5) is installed on the static pile driver, and the static pile driver holds the column segment (3) through the clamp (5) to perform pile pressing operation.

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