Full-recovery prestressed square pile and latticed column combined upright pile construction method

Abstract

The invention discloses a fully-recycled prestressed square pile and latticed column combined stand column pile construction method, and belongs to the technical field of green foundation pit supporting. According to the construction method of the fully-recycled prestressed square pile and latticed column combined stand column pile, the prestressed square pile serves as the lower section of the stand column pile and is organically combined with the latticed column, the stand column pile can be pressed into the designed elevation through static pressure equipment, and the construction method has the advantages of being low in construction cost, high in construction efficiency, free of pollution and the like; the stand column piles are integrally pressed into a soil body, the foundation pit soil body is excavated layer by layer, concrete supports and surrounding purlins on the periphery of a foundation pit are supported layer by layer through self-servo hydraulic converters and supporting cross beams, foundation pit construction operation is easy and efficient, and construction is safer and more stable; moreover, after a bottom plate and structural floor slabs of all layers are built, the stand column piles can be recycled by 100%, zero emission is truly achieved, the low-carbon, environment-friendly and green construction effects are achieved, in addition, sensors can be arranged in the pile sections of the prestressed square piles, and foundation pit full-section monitoring and deformation control are achieved.

Description

Technical Field

[0001] The invention relates to a construction method of column piles for foundation pit support, and more specifically to a construction method of column piles composed of fully-recoverable prestressed square piles and lattice columns. Background Art

[0002] With the acceleration of urbanization and the continuous deepening of infrastructure construction, deep foundation pit projects play an increasingly important role in the development of high-rise buildings and underground spaces. The stability and safety of foundation pit support structures are directly related to the success of the project and the safety of the surrounding environment. The design and construction technology of foundation pit support structures have been continuously improved with the development of construction engineering technology. Among the many foundation pit support structures, column piles are a key vertical load-bearing component, and their design and construction technology have always been a research hotspot in the field of geotechnical engineering. Traditional foundation pit support structures mainly include cast-in-place piles, steel sheet piles, underground continuous walls, etc. While these structures provide the necessary vertical and lateral support, they also have certain limitations. For example, cast-in-place piles have a long construction period, high cost, and a great impact on the environment; although steel sheet piles have a fast construction speed, their bearing capacity is limited and they are difficult to drive in under certain geological conditions. Specifically, the existing column piles are generally composed of two parts. The lower section is generally cast-in-place piles or pipe piles, rigid composite piles, and the upper section is located in the foundation pit section. It is generally a steel lattice column or steel pipe, which has the following technical limitations:

[0003] a. Conventional cast-in-place piles have large mud pollution and high cost;

[0004] b. The pipe pile as the lower pile body has poor pull-out resistance. At the same time, since the pipe pile is connected to the upper steel lattice column through the inner core of the pipe pile, there are two major problems: first, the connection stiffness is poor, and second, concrete needs to be poured, and the concrete strength needs a long consolidation time;

[0005] c. The rigid composite pile is used as the lower pile body, and the pipe pile is inserted into the rigid composite pile, which also has the same problem as problem b;

[0006] d. For all the above types, the column piles cannot be recycled, and the effect of low-carbon, environmental protection and green construction cannot be achieved;

[0007] e. For all the above types, in actual construction, except for the test piles, no stress and displacement monitors and axial force detectors were installed, so that the actual deformation state of the foundation pit column piles could not be fully analyzed and monitored, and the safety of the foundation pit could not be effectively guaranteed;

[0008] f. All the above types are used as the connection points between the column pile and the concrete support or steel support. In the first case, the reinforced concrete and the concrete support are usually cast in situ to form a fixed hinge point, which will be removed later. In the second case, the steel pipe or steel column is usually connected to the steel support by bolts or welding, which cannot cope with the problem of excessive support deformation caused by foundation pit deformation.

[0009] Therefore, researching and developing new foundation pit support structures has important practical significance.

[0010] The application of precast square piles as column piles has gradually become a new trend in foundation pit support structures due to its advantages such as fast construction speed, easy quality control, and high cost-effectiveness. Precast pile technology has been widely used in the field of foundation pit support due to its advantages such as speed, economy, and environmental protection. Precast piles are piles pre-manufactured in factories with uniform quality standards and specifications, which can greatly reduce the time and cost of on-site construction. Types of precast piles include prestressed concrete pipe piles (PC piles), prestressed high-strength concrete pipe piles (PHC piles), and steel piles. These precast piles can be quickly driven into the soil by static pressure, hammering, or vibration during the construction process to form a stable foundation pit support structure. The application of precast square piles as column piles is mainly based on the following backgrounds:

[0011] 1) Improvement of construction efficiency: Traditional foundation pit support structures have a long construction period and require on-site concrete pouring or complex welding operations. The use of prefabricated square piles can significantly shorten the construction period and improve construction efficiency. After prefabricated square piles are prefabricated in the factory, they can be directly transported to the construction site for installation, reducing the time and labor requirements for on-site operations.

[0012] 2) Cost control: Prefabricated square piles can significantly reduce material waste and construction costs due to their factory-based production characteristics. Compared with traditional cast-in-place piles, prefabricated piles reduce the time for on-site pouring and maintenance, thereby reducing the overall cost of the project.

[0013] 3) Reduced environmental impact: The factory production of prefabricated square piles reduces noise and dust pollution during on-site construction, and has less impact on the surrounding environment. In addition, the standardized production of prefabricated piles also helps reduce the generation of construction waste.

[0014] 4) Improvement of structural safety and stability: Prefabricated square piles can provide more uniform and stable bearing capacity due to their uniform materials and precise geometric dimensions. In addition, the combination of prefabricated square piles and steel columns can further improve the stability and safety of the foundation pit support structure.

[0015] However, although prefabricated square piles have many advantages as column piles, they also face some technical challenges in practical applications, mainly including:

[0016] A. Connection technology

[0017] The connection technology between prefabricated square piles and other structures in the foundation pit (such as steel columns, support beams, etc.) is the key. How to ensure the stability and reliability of the connection is a technical problem in the application of prefabricated square piles. In the prior art, a variety of connection methods have been proposed, such as mechanical connection, welding connection and anchor connection, to meet different engineering needs.

[0018] B. Adaptability

[0019] Different geological conditions put forward different requirements for the design and construction of prefabricated square piles. Prefabricated square piles need to have good adaptability to adapt to different soil conditions and bearing requirements.

[0020] C. Economic Analysis

[0021] The economic analysis of prefabricated square piles is an important factor in determining their application scope. Material cost, construction cost and maintenance cost need to be comprehensively considered to evaluate the economic feasibility of prefabricated square piles in different projects. Summary of the invention

[0022] 1. Technical problem to be solved by the invention

[0023] The purpose of the present invention is to overcome the shortcomings of the existing column piles, such as long construction period and poor recyclability, and provide a fully recyclable prestressed square pile plus lattice column combined column pile construction method. The technical scheme of the present invention is adopted, and the prestressed square pile is used as the lower section of the column pile, and is organically combined with the lattice column. It can be pressed into the designed elevation by static pressure equipment, and has the advantages of low construction cost, high construction efficiency and no pollution. By pressing the column pile into the soil as a whole, excavating the foundation pit soil layer by layer, and supporting the concrete support and surrounding purlin around the foundation pit layer by layer with a self-servo hydraulic converter and a supporting beam, the foundation pit construction operation is simpler and more efficient, and the construction is safer and more stable. Moreover, after the construction of the bottom plate and each layer of the structural floor slab is completed, the column pile can be 100% recycled, truly achieving zero emission, and realizing the effect of low-carbon, environmental protection and green construction.

[0024] In addition, since this construction method can achieve 100% recovery of the column piles, sensors such as stress monitors, displacement monitors and axial force detectors can be built into the prestressed square pile sections, and the full-section monitoring of the foundation pit can be achieved in conjunction with the background monitoring system; the background monitoring system can also control the output pressure of the self-servo hydraulic converter based on the foundation pit deformation obtained by the built-in sensors, thereby effectively suppressing the deformation of the foundation pit.

[0025] 2. Technical solution

[0026] In order to achieve the above object, the technical solution provided by the present invention is:

[0027] The construction method of the fully-recoverable prestressed square pile plus lattice column combined column pile of the present invention comprises the following construction steps:

[0028] S1. Using static pressure equipment to press a prestressed square pile segment into the foundation pit soil; the prestressed square pile segment includes a plurality of prestressed prefabricated square pile sections, and two adjacent prestressed prefabricated square pile sections are connected via a prefabricated square pile connector; the upper end of the prestressed prefabricated square pile located at the uppermost part is also connected to a prestressed square pile modification section via a prefabricated square pile connector;

[0029] S2, installing a lattice column segment at the upper end of the prestressed square pile segment, and using static pressure equipment to press the lattice column segment and the prestressed square pile segment together to the designed elevation; the lattice column segment includes a plurality of lattice column sections, two adjacent lattice column sections are connected by a detachable lattice column connecting section, and the lattice column located at the bottom is connected to the prestressed square pile modification section;

[0030] S3, excavating the foundation pit soil layer by layer, and sequentially constructing each layer of concrete support and surrounding purlin around the foundation pit; after excavating the surface foundation pit soil, installing a self-servo hydraulic converter with a four-way servo automatic compensation hydraulic mechanism on the upper end of the lattice column located at the uppermost part, and connecting the self-servo hydraulic converters of adjacent column piles and the self-servo hydraulic converters with the first layer of concrete support by using supporting crossbeams; then excavating the lower soil layer layer by layer, replacing the corresponding lattice column connection joints with the self-servo hydraulic converters, and similarly connecting the self-servo hydraulic converters of adjacent column piles and the self-servo hydraulic converters with each layer of concrete support by using supporting crossbeams;

[0031] S4, constructing the bottom plate and the structural floor plates of each layer in sequence from the bottom of the foundation pit upwards, leaving gaps between the bottom plate and the structural floor plates of each layer and the lattice column pile sections for lifting and recovering the column piles;

[0032] S5. After the base plate and the structural floor slabs of each floor have reached the designed strength, the column piles are dismantled by pulling out equipment, and the prestressed square pile sections and lattice column pile sections are recovered.

[0033] Furthermore, step S1 further comprises the following sub-steps:

[0034] S1-1. After the pile position is determined, the first section of the prestressed prefabricated square pile is pressed into the foundation pit soil using static pressure equipment, and then the next section of the prestressed prefabricated square pile is hoisted and connected to the upper end of the prestressed prefabricated square pile that has been pressed into the foundation pit soil through a prefabricated square pile connector, and the static pressure equipment is continued to perform pile pressing operations; after the static pressure of all prestressed prefabricated square piles is completed, the prestressed square pile modification section is connected to the upper end of the uppermost prestressed prefabricated square pile through a prefabricated square pile connector, and the static pressure equipment is continued to perform pile pressing operations on the prestressed square pile modification section;

[0035] S1-2. Install the conversion connection block at the lower end of the square pile driver, hoist the square pile driver and connect it with the upper end of the prestressed square pile modification section through the conversion connection block, and use static pressure equipment to hold and press the square pile driver until the prestressed square pile section is pressed to the designed depth.

[0036] Furthermore, the prestressed prefabricated square piles are provided with end embedded connectors at the four corners of the upper and lower ends, and the prefabricated square pile connector is composed of four angle steels for connecting with the end embedded connectors; the lower end of the prestressed square pile modification section is provided with a modification section lower end embedded screw sleeve for connecting with the prefabricated square pile connector, and the upper end of the prestressed square pile modification section is provided with a modification section upper end connecting angle steel for connecting with the lower end of the lattice column.

[0037] Furthermore, in step S2, the lattice column is a steel lattice column or a concrete lattice column or a reinforced steel plate lattice column, wherein:

[0038] The steel lattice column is welded by lattice column angle steel and lattice column tie plate;

[0039] The concrete lattice column comprises a steel lattice column body welded by lattice column angle steel and lattice column tie plates, and reinforced concrete poured and filled in the steel lattice column body;

[0040] The reinforced steel plate lattice column comprises a steel lattice column body welded from lattice column angle steels and lattice column tie plates, and a reinforced steel sleeve sleeved and fixed inside the steel lattice column body. A reinforced side plate located between adjacent lattice column angle steels is also fixed on the outer side wall of the reinforced steel sleeve.

[0041] Furthermore, when the lattice column is a steel lattice column, a pulley limiter is further provided on the lattice column plate of the steel lattice column, a steel pallet is installed on the top of the prestressed square pile modification section, the steel lattice column is connected to the prestressed square pile modification section, a casing pile driver is sleeved on the outer side of the steel lattice column, the pulley limiter is distributed circumferentially along the inner side wall of the casing pile driver, and can roll up and down relative to the inner side wall of the casing pile driver, the lower end of the casing pile driver abuts against the steel pallet, and the static pressure equipment presses the prestressed square pile section and the steel lattice column into the soil to the designed elevation through the casing pile driver.

[0042] Furthermore, when the lattice column is a concrete lattice column or a reinforced steel plate lattice column, the static pressure equipment directly holds and presses the concrete lattice column or the reinforced steel plate lattice column to press the prestressed square pile segments and the lattice column into the soil to the designed elevation.

[0043] Furthermore, in step S3, when the self-servo hydraulic converter replaces the corresponding lattice column connecting section, the upper and lower adjacent lattice columns are temporarily connected through a temporary converter, and the temporary converter is composed of four outward-expanding connecting parts. The four outward-expanding connecting parts can gradually replace the lattice column connecting sections to connect the upper and lower adjacent lattice columns when the lattice column connecting sections are removed, and an enlarged space for installing the self-servo hydraulic converter is formed between the four outward-expanding connecting parts; when installing the self-servo hydraulic converter, the four outward-expanding connecting parts are removed one by one in sequence.

[0044] Furthermore, in step S3, the self-servo hydraulic converter includes a hydraulic converter main box, a detachable converter connecting plate, a hydraulic jack connecting plate, a hydraulic jack cylinder sleeve and a hydraulic jack oil cylinder, the hydraulic converter main box is a rectangular structure, the detachable converter connecting plate is respectively installed on the upper and lower end surfaces of the hydraulic converter main box, and is used to connect with the upper and lower adjacent lattice columns, the hydraulic jack connecting plates are respectively fixedly installed on the four sides of the hydraulic converter main box, and each of the hydraulic jack connecting plates is provided with a group of hydraulic jack cylinder sleeves and hydraulic jack oil cylinders. jack cylinder; a beam connecting plate is fixed to one end of the supporting beam, and the beam connecting plate has a positioning hole that matches the hydraulic jack cylinder; the hydraulic jack connecting plate and the beam connecting plate are both "I"-shaped structures. When the supporting beam is connected to the self-servo hydraulic converter, the telescopic end of the hydraulic jack cylinder is inserted into the positioning hole of the supporting beam, and a connecting screw for preventing falling is also provided between the hydraulic jack connecting plate and the beam connecting plate, and an axial movable margin is provided between the connecting screw and the corresponding hydraulic jack connecting plate and / or beam connecting plate.

[0045] Furthermore, in the prestressed square pile section, at least one of the prestressed prefabricated square pile and the prestressed square pile modification section has a built-in sensor, the built-in sensor includes a stress monitor, a displacement monitor and an axial force detector, and the built-in sensor is communicatively connected to a background monitoring system via a wireless communication module; the background monitoring system is also communicatively connected to a self-servo hydraulic converter, and the background monitoring system controls the output pressure of the self-servo hydraulic converter according to the foundation pit deformation obtained by monitoring by the built-in sensor.

[0046] Furthermore, in step S5, the lifting and pulling equipment includes a balanced vertical hydraulic jack, and the prestressed prefabricated square piles, the prestressed square pile modification sections and the lattice columns located at the bottom are reserved with lifting and pulling holes that cooperate with the balanced vertical hydraulic jacks at intervals in the up-down direction. The balanced vertical hydraulic jack has two structurally symmetrical left and right parts, and both the left and right parts include a semi-ring fixing seat, a fixing plate, a hydraulic cylinder, a lifting slide and a pushing rod. The fixing plate is arranged at the lower part of the semi-ring fixing seat, the hydraulic cylinder is fixed on the fixing plate, the lifting slide is slidably arranged on the semi-ring fixing seat up and down, and is connected to the driving end of the hydraulic cylinder, and the pushing rod is horizontally fixed on the lifting slide; the semi-ring fixing seats of the left and right parts can be docked to form an annular seat that embraces the column pile, and the pushing rods of the left and right parts can be axially docked and inserted into the corresponding lifting and pulling holes, and the column pile is lifted and recovered by utilizing the pushing force generated by the hydraulic cylinder.

[0047] 3. Beneficial effects

[0048] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0049] (1) The fully recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention utilizes prestressed square piles as the lower section of the column piles, and organically combines them with the lattice columns, and can be pressed into the designed elevation by static pressure equipment, which has the advantages of low construction cost, high construction efficiency and no pollution. By pressing the column piles into the soil as a whole, excavating the foundation pit soil layer by layer, and supporting the concrete supports and surrounding purlins around the foundation pit layer by layer using self-servo hydraulic converters and supporting beams, the foundation pit construction operation is simpler and more efficient, and the construction is safer and more stable. Moreover, after the construction of the bottom plate and each layer of structural floor slabs is completed, the column piles can be 100% recycled, truly achieving zero emissions, and realizing the effects of low-carbon, environmentally friendly and green construction.

[0050] (2) The method for constructing a fully recyclable prestressed square pile plus lattice column combined column pile of the present invention uses a square pile delivery device in conjunction with a conversion connection block to press the prestressed square pile section to a designed depth for the portion outside the holding and pressing stroke during static pressure of the prestressed square pile section. The construction is simple and convenient, and the holding and pressing is stable and reliable.

[0051] (3) The fully recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention has end embedded connectors at the upper and lower ends and four corners of the prestressed prefabricated square pile, and the prefabricated square pile connector is composed of four angle steels for connecting with the end embedded connectors; the lower end of the prestressed square pile modification section has a modification section lower end embedded screw sleeve for connecting with the prefabricated square pile connector, and the upper end of the prestressed square pile modification section has a modification section upper end connecting angle steel for connecting with the lower end of the lattice column; the use of the above-mentioned embedded connectors ensures the connection accuracy and strength, and the use of angle steel structure for connection makes the connection operation simple and the connection firm and reliable.

[0052] (4) The fully-recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention, wherein the lattice column is a steel lattice column or a concrete lattice column or a reinforced steel plate lattice column. When the lattice column is a steel lattice column, a pulley stopper is further provided on the lattice column plate of the steel lattice column. A steel tray is installed on the top of the prestressed square pile modification section. The steel lattice column is connected to the prestressed square pile modification section. A casing pile driver is sleeved on the outer side of the steel lattice column. The pulley stopper is distributed circumferentially along the inner side wall of the casing pile driver and can be relative to the inner side of the casing pile driver. The wall rolls up and down, and the lower end of the casing pile driver abuts against the steel tray. The static pressure equipment presses the prestressed square pile segment and the steel lattice column into the soil to the designed elevation through the casing pile driver. The casing pile driver design can solve the problem that the steel lattice column cannot withstand radial pressure, and realizes the purpose that the prestressed square pile segment and the steel lattice column can be statically pressed into the soil together. The construction method is novel and efficient, and the pulley limiter can ensure the matching accuracy of the steel lattice column and the casing pile driver, which can effectively avoid the problem of inclination of the steel lattice column.

[0053] When the lattice column is a concrete lattice column or a reinforced steel plate lattice column, the static pressure equipment directly hugs and presses the concrete lattice column or the reinforced steel plate lattice column to press the prestressed square pile segments and the lattice column into the soil to the designed elevation. The design of concrete lattice column and reinforced steel plate lattice column can make the lattice column have radial pressure bearing capacity, thereby achieving the effect of directly hugging and pressing into the soil. For deep foundation pits, the construction is simpler and more convenient.

[0054] (5) The fully recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention, when the self-servo hydraulic converter replaces the corresponding lattice column connection section, the upper and lower adjacent lattice columns are temporarily connected through a temporary converter, and the temporary converter is composed of four outward expansion connectors. The four outward expansion connectors can gradually replace the lattice column connection section to connect the upper and lower adjacent lattice columns when the lattice column connection section is removed, and an enlarged space for installing the self-servo hydraulic converter is formed between the four outward expansion connectors; when installing the self-servo hydraulic converter, the four outward expansion connectors are disassembled one by one in turn; the use of the above-mentioned temporary converter can facilitate the installation of the self-servo hydraulic converter while ensuring construction safety, and has the advantages of simple structure and easy operation.

[0055] (6) The present invention provides a method for constructing a fully recyclable prestressed square pile plus a lattice column combined column pile, wherein the self-servo hydraulic converter comprises a hydraulic converter main box, a detachable converter connecting plate, a hydraulic jack connecting plate, a hydraulic jack cylinder sleeve and a hydraulic jack oil cylinder. The self-servo hydraulic converter has a compact structure and can be connected to the supporting beam in a "cross" direction on a horizontal plane. It has good supporting stability for the foundation pit and is convenient for the construction of subsequent layers. In addition, the self-servo hydraulic converter is reliably connected to the supporting beam. A connecting screw for preventing falling is provided between the hydraulic jack connecting plate and the beam connecting plate. An axial movable margin is provided between the connecting screw and the corresponding hydraulic jack connecting plate and / or the beam connecting plate, so that the self-servo hydraulic converter can automatically compensate for the axial force of the supporting beam and can effectively prevent the supporting beam from accidentally falling, thereby ensuring construction safety.

[0056] (7) The present invention provides a method for constructing a fully recyclable prestressed square pile plus lattice column combined column pile. In the prestressed square pile section, at least one of the prestressed prefabricated square pile and the prestressed square pile modified section has a built-in sensor. The built-in sensor includes a stress monitor, a displacement monitor and an axial force detector. The built-in sensor is connected to the background monitoring system through a wireless communication module. Since the construction method can achieve 100% full recovery of the column pile, stress monitors, displacement monitors, axial force detectors and other sensors can be built into the prestressed square pile section. The background monitoring system can realize full-section monitoring of the foundation pit in conjunction with the background monitoring system. The background monitoring system is also connected to the self-servo hydraulic converter. The background monitoring system controls the output pressure of the self-servo hydraulic converter based on the foundation pit deformation obtained by the built-in sensor, thereby effectively suppressing the foundation pit deformation.

[0057] (8) The present invention provides a fully recyclable prestressed square pile plus lattice column combined column pile construction method, wherein the lifting and pulling equipment includes a balanced vertical hydraulic jack. The prestressed prefabricated square pile, the prestressed square pile modification section, and the lattice column located at the bottom are provided with lifting and pulling holes that cooperate with the balanced vertical hydraulic jack at intervals in the upper and lower directions. The balanced vertical hydraulic jack can be used in conjunction with a crane to achieve the lifting and pulling of the column pile, making the lifting and pulling and recovery of the column pile more convenient and quick, and the lifting and pulling operation is safe and reliable. In addition, the balanced vertical hydraulic jack is installed on the base plate to prevent damage to the base plate during the lifting and pulling process.

[0058] (9) The fully recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention adopts a two-petal combination structure for the balanced vertical hydraulic jack, which uses two sets of symmetrical hydraulic cylinders and push-pull rods to push and pull the column piles, thereby ensuring the balance of the pulling force and realizing the vertical pulling of the column piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the composition of the column pile in the column pile construction method of the present invention;

[0060] Figure 2 It is a schematic diagram of the steps of pressing prestressed prefabricated square piles into foundation pit soil in the column pile construction method of the present invention;

[0061] Figure 3 It is a schematic diagram of the steps of using a square pile driver to press piles in the column pile construction method of the present invention;

[0062] Figure 4 It is a perspective structural schematic diagram of prestressed prefabricated square piles in the column pile construction method of the present invention;

[0063] Figure 5 It is a perspective structural schematic diagram of a prestressed square pile modification section in the column pile construction method of the present invention;

[0064] Figure 6 It is a schematic diagram of the steps of installing a steel tray on a prestressed square pile modification section in the column pile construction method of the present invention;

[0065] Figure 7 It is a structural schematic diagram of a steel pallet in the column pile construction method of the present invention;

[0066] Figure 8 It is a schematic diagram of the steps of installing lattice column pile sections in the column pile construction method of the present invention;

[0067] Fig. 9 It is a structural schematic diagram of a steel lattice column in the column pile construction method of the present invention;

[0068] Fig.10 It is a schematic diagram of the overall structure of the lattice column connection section in the column pile construction method of the present invention;

[0069] Fig.11 It is a schematic diagram of the split structure of the lattice column connection section in the column pile construction method of the present invention;

[0070] Fig.12 It is a schematic diagram of the steps of using a casing pile driver to deliver piles in the column pile construction method of the present invention;

[0071] Fig.13 It is a schematic diagram of the coordination state between the casing pile driver and the lattice column pile section in the column pile construction method of the present invention;

[0072] Fig.14 It is a schematic diagram of the steel lattice column in the present invention cooperating with the casing pile driver through the pulley stopper;

[0073] Fig.15 It is a schematic diagram of the steps of using a self-servo hydraulic converter to support in the column pile construction method of the present invention;

[0074] Fig.16 It is a schematic diagram of the state of installing a temporary converter in the column pile construction method of the present invention;

[0075] Fig.17 It is a schematic diagram of the state of installing a self-servo hydraulic converter in the column pile construction method of the present invention;

[0076] Fig.18 It is a schematic diagram of installing a supporting beam through a self-servo hydraulic converter in the column pile construction method of the present invention;

[0077] Fig.19 It is a structural schematic diagram of installing upper and lower lattice columns through a temporary converter in the column pile construction method of the present invention;

[0078] Fig. 20 It is a structural schematic diagram of a self-servo hydraulic converter in the column pile construction method of the present invention;

[0079] Fig.21 It is a structural schematic diagram of a supporting beam in the column pile construction method of the present invention;

[0080] Fig. 22 It is a schematic diagram of the steps of pulling out the column piles in the column pile construction method of the present invention;

[0081] Fig.23 It is a schematic diagram of the state of lifting the column pile by the balanced vertical hydraulic jack in the column pile construction method of the present invention;

[0082] Fig.24 It is a schematic diagram of the combined state of the balanced vertical hydraulic jack in the column pile construction method of the present invention;

[0083] Fig.25 It is a schematic diagram of the split state of the balanced vertical hydraulic jack in the column pile construction method of the present invention;

[0084] Fig.26 It is a structural schematic diagram of a column pile using a concrete lattice column in the column pile construction method of the present invention;

[0085] Fig. 27 It is a structural schematic diagram of a concrete lattice column in the column pile construction method of the present invention;

[0086] Fig.28 It is a structural schematic diagram of a column pile using a reinforced steel plate lattice column in the column pile construction method of the present invention;

[0087] Fig.29 It is a schematic diagram of the overall structure of the reinforced steel plate lattice column in the column pile construction method of the present invention;

[0088] Fig.30 It is a schematic diagram of the split structure of the reinforced steel plate lattice column in the column pile construction method of the present invention.

[0089] Explanation of the symbols in the schematic diagram:

[0090] 100. Prestressed square pile segment; 11. Prestressed prefabricated square pile; 11-1. Prefabricated square pile steel cage; 11-2. End embedded connector; 11-3. Square pile embedded end plate; 11-4. Embedded casing; 11-5. First built-in sensor; 11-6. Prefabricated square pile concrete; 12. Prefabricated square pile connector; 13. Prestressed square pile modified section; 13-1. Modified section angle steel; 13-2. Modified section reinforcement plate; 13-3. Modified section steel cage; 13-4. Modified section lower end embedded screw sleeve; 13-5. Modified section embedded end plate; 13-6. Second built-in sensor; 13-7. Modified section concrete; 13-8. Modified section upper end connecting angle steel;

[0091] 200, lattice column pile segment; 21, lattice column; 21A, steel lattice column; 21B, concrete lattice column; 21C, reinforced steel plate lattice column; 21-1, lattice column angle steel; 21-2, lattice column tie plate; 21-3, lattice column connection; 21-4, pulley stopper; 21-5, reinforced concrete; 21-6, reinforced steel sleeve; 21-7, reinforced side plate; 22, lattice column connection section; 22-1, connection section reinforced tie plate; 22-2, connection section angle steel; 22-3, connection section connection; 22-4, Bolt connection hole; 23, temporary converter; 23-1, external expansion connector; 24, self-servo hydraulic converter; 24-1, hydraulic converter main box; 24-2, detachable converter connection plate; 24-3, hydraulic jack connection plate; 24-3a, movable connection hole; 24-4, hydraulic jack cylinder sleeve; 24-5, hydraulic jack cylinder; 24-6, hydraulic pipeline; 24-7, sensor connection pipeline; 25, steel pallet; 25-1, pallet body; 25-2, installation hole; 25-3, support rib;

[0092] 300, casing pile driver; 31, latch; 400, supporting beam; 41, prestressed concrete supporting column; 42, embedded end connector; 43, beam connecting plate; 44, positioning hole; 500, balanced vertical hydraulic jack; 51, semi-ring fixing seat; 51-1, slideway; 51-2, locking hole; 52, fixing plate; 53, hydraulic cylinder; 54, lifting slide; 55, pushing rod; 601, foundation pit base stratum; 602, foundation pit soil; 603, concrete support; 604, bottom plate; 605, structural floor; 700, static pressure equipment; 701, square pile driver; 701a, conversion connection block. DETAILED DESCRIPTION

[0093] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0094] [Example 1]

[0095] Combination Figures 1 to 25 As shown, the fully-recoverable prestressed square pile plus lattice column combined column pile of this embodiment mainly consists of two parts: a prestressed square pile segment 100 and a lattice column segment 200. The lattice column segment 200 is connected to the upper end of the prestressed square pile segment 100. The prestressed square pile segment 100 is located in the bottom stratum 601 of the foundation pit, and the lattice column segment 200 is located in the foundation pit. The construction method of the fully-recoverable prestressed square pile plus lattice column combined column pile includes the following construction steps:

[0096] S1, such as Figure 2 and Figure 3As shown, a prestressed square pile segment 100 is pressed into the foundation pit soil 602 by using a static pressure device 700; the prestressed square pile segment 100 includes a plurality of prestressed prefabricated square piles 11, and two adjacent prestressed prefabricated square piles 11 are connected by a prefabricated square pile connector 12; the upper end of the prestressed prefabricated square pile 11 at the top is also connected to a prestressed square pile modification segment 13 by a prefabricated square pile connector 12. Specifically, the following sub-steps are included:

[0097] S1-1, such as Figure 2 After the pile position is determined, the first section of the prestressed prefabricated square pile 11 is pressed into the foundation pit soil 602 by using the static pressure equipment 700, and then the next section of the prestressed prefabricated square pile 11 is hoisted, and connected to the upper end of the prestressed prefabricated square pile 11 that has been pressed into the foundation pit soil 602 through the prefabricated square pile connector 12, and the static pressure equipment 700 is continued to perform the pile pressing operation; after the static pressure of all the prestressed prefabricated square piles 11 is completed, the upper end of the uppermost prestressed prefabricated square pile 11 is connected to the prestressed square pile modification section 13 through the prefabricated square pile connector 12, and the static pressure equipment 700 is continued to perform the pile pressing operation on the prestressed square pile modification section 13;

[0098] S1-2, such as Figure 3 Since the static pressure device 700 adopts a holding and pressing method, it cannot completely press the prestressed square pile modification section 13 into place. For this reason, the square pile delivery device 701 can be used to complete further pile delivery operations. Specifically, a conversion connection block 701a is installed at the lower end of the square pile delivery device 701. The conversion connection block 701a can be matched and docked with the upper end of the prestressed square pile modification section 13. The square pile delivery device 701 is hoisted and docked with the upper end of the prestressed square pile modification section 13 through the conversion connection block 701a. The static pressure device 700 is used to hold and press the square pile delivery device 701 until the prestressed square pile segment 100 is pressed to the designed depth. For the part outside the holding and pressing stroke, the square pile delivery device 701 is used to cooperate with the conversion connection block 701a to press the prestressed square pile segment 100 to the designed depth. The construction is simple and convenient, and the holding and pressing is stable and reliable. The static pressure device 700 in the above step S1 may be a square pile clamp, which uses a hydraulic clamping mechanism to clamp the pile body and uses a vertical hydraulic cylinder to press the pile body into the soil.

[0099] S2, reference Figure 8 As shown, a lattice column segment 200 is installed on the upper end of the prestressed square pile segment 100, and the lattice column segment 200 and the prestressed square pile segment 100 are pressed to the designed elevation by a static pressure device 700; specifically, the lattice column segment 200 includes a plurality of lattice columns 21, and two adjacent lattice columns 21 are connected by a detachable lattice column connecting segment 22, and the lattice column 21 at the bottom is connected to the prestressed square pile modification segment 13. Fig. 9As shown, in this embodiment, the lattice column 21 is a steel lattice column 21A, which is welded by a lattice column angle steel 21-1 and a lattice column tie plate 21-2, that is, the steel lattice column 21A is an existing common lattice column, and a lattice column connecting portion 21-3 is respectively provided at the upper and lower ends of the lattice column angle steel 21-1. Since the radial pressure bearing capacity of the steel lattice column 21A is relatively poor, it is impossible to directly use the static pressure equipment 700 to hold the pressure. In order to facilitate the delivery of the steel lattice column 21A, as shown in FIG. Figure 12 to Figure 14 As shown, a pulley stopper 21-4 is also provided on the lattice column plate 21-2 of the steel lattice column 21A, a steel tray 25 is installed on the top of the prestressed square pile modification section 13, the steel lattice column 21A is connected to the prestressed square pile modification section 13, a casing pile driver 300 is sleeved on the outer side of the steel lattice column 21A, the pulley stopper 21-4 is circumferentially distributed along the inner wall of the casing pile driver 300, and can roll up and down relative to the inner wall of the casing pile driver 300, the lower end of the casing pile driver 300 abuts against the steel tray 25, and the static pressure equipment 700 presses the prestressed square pile segment 100 and the steel lattice column 21A into the soil to the designed elevation through the casing pile driver 300. The use of the casing pile driver 300 can solve the problem that the steel lattice column 21A cannot withstand radial pressure, and achieves the purpose of statically pressing the prestressed square pile segment 100 and the steel lattice column 21A into the soil together. The construction method is novel and efficient. In addition, the use of the pulley limiter 21-4 can ensure the matching accuracy between the steel lattice column 21A and the casing pile driver 300, and can effectively avoid the problem of the steel lattice column tilting. Further, if Fig.14 As shown, a pin hole may be provided on the casing pile driver 300. After the casing pile driver 300 is sleeved on the outside of the lattice column 21, a latch 31 may be installed on the casing pile driver 300 by using the pin hole. The latch 31 passes through the square gap on the lattice column 21, which can prevent the casing pile driver 300 and the lattice column 21 from rotating at a large angle relative to each other, further ensuring the pile driving stability of the casing pile driver 300. In this step, the static pressure device 700 is a round pipe pile clamp.

[0100] S3. Reference Figures 15 to 18As shown, the foundation pit soil 602 is excavated layer by layer, and each layer of concrete support 603 and surrounding purlins are sequentially constructed around the foundation pit; after the surface foundation pit soil 602 is excavated, a self-servo hydraulic converter 24 with a four-way servo automatic compensation hydraulic mechanism is installed at the upper end of the lattice column 21 located at the uppermost part, and the self-servo hydraulic converter 24 of the adjacent column piles, and the self-servo hydraulic converter 24 are connected to the first layer of concrete support 603 by using the supporting crossbeam 400; then the lower soil is excavated layer by layer, and the self-servo hydraulic converter 24 is used to replace the corresponding lattice column connecting section 22, and the self-servo hydraulic converter 24 of the adjacent column piles, and the self-servo hydraulic converter 24 are connected to each layer of concrete support 603 by using the supporting crossbeam 400. Specifically, when the self-servo hydraulic converter 24 replaces the corresponding lattice column connection section 22, the upper and lower adjacent lattice columns 21 are temporarily connected through the temporary converter 23. The temporary converter 23 is composed of four outward expansion connectors 23-1. The upper and lower ends of the outward expansion connector 23-1 respectively have relative U-shaped connection parts, so that the size of the outward expansion connector 23-1 is expanded outward after being installed on the lattice column 21. In this way, the four outward expansion connectors 23-1 can gradually replace the lattice column connection section 22 to connect the upper and lower adjacent lattice columns 21 when the lattice column connection section 22 is removed, and an enlarged space for installing the self-servo hydraulic converter 24 is formed between the four outward expansion connectors 23-1, so as to facilitate the subsequent installation of the self-servo hydraulic converter 24. Since the upper and lower adjacent lattice columns 21 are fixed, in order to facilitate the disassembly of the lattice column connection section 22, refer to Fig.10 and Fig.11 As shown, the lattice column connection section 22 in this embodiment adopts a two-half split structure design. The lattice column connection section 22 is mainly composed of four connection section reinforcement plates 22-1 and four connection section angle steels 22-2. The upper and lower ends of the connection section angle steel 22-2 are respectively provided with connection section connection parts 22-3 for connecting with the lattice column 21, wherein two connection section reinforcement plates 22-1 are vertically welded and fixed on a connection section angle steel 22-2, and another connection section angle steel 22-2 is welded to one side of one of the connection section reinforcement plates 22-1 to form an independent welded part. The left and right halves of the welded parts have the same structure. After the two halves are butt-jointed, they are fixedly connected by bolts. Bolt connection holes 22-4 are respectively provided at the joints of the left and right halves of the welded parts. When disassembling the lattice column connection section 22, first remove the welded parts on one side, and temporarily support them with the above-mentioned outward expansion connector 23-1. Then remove the welded parts on the other side, and also temporarily support them with the above-mentioned outward expansion connector 23-1 to form a welded part. Fig.19When installing the self-servo hydraulic converter 24, the four outward expansion connectors 23-1 are disassembled one by one in sequence. Specifically, one of the outward expansion connectors 23-1 can be disassembled first, and then the self-servo hydraulic converter 24 is placed between the upper and lower lattice columns 21, and the upper and lower ends of the self-servo hydraulic converter 24 are respectively connected to the upper and lower lattice columns 21 after the outward expansion connectors 23-1 are removed, and then the outward expansion connectors 23-1 are removed one by one and the self-servo hydraulic converter 24 is connected. The above-mentioned temporary converter 23 can facilitate the installation of the self-servo hydraulic converter 24 while ensuring construction safety, and has the advantages of simple structure and convenient operation.

[0101] S4, such as Fig. 22 As shown, the bottom plate 604 and the structural floors 605 of each layer are sequentially constructed from the bottom of the foundation pit upwards, and a gap for pulling out and recovering the column piles is reserved between the bottom plate 604 and the structural floors 605 of each layer and the lattice column pile sections 200. In other words, a hole larger than the outer circumference of the self-servo hydraulic converter 24 is reserved on the bottom plate 604 and the structural floors 605 of each layer, and the hole can be blocked after the column piles are removed.

[0102] S5. After the bottom plate 604 and the structural floor slabs 605 of each layer have reached the designed strength, the supporting beams 400 of each layer are first removed, and then the column piles are pulled out and disassembled by using the pulling equipment, and the prestressed square pile segments 100 and the lattice column segments 200 are recovered.

[0103] The fully recyclable prestressed square pile plus lattice column combined column pile construction method of this embodiment uses prestressed square piles as the lower section of the column piles, and is organically combined with the lattice columns, and can be pressed into the designed elevation by static pressure equipment, which has the advantages of low construction cost, high construction efficiency and no pollution. By pressing the column piles into the soil as a whole, excavating the foundation pit soil layer by layer, and supporting the concrete supports and surrounding purlins around the foundation pit layer by layer with self-servo hydraulic converters and supporting beams, the foundation pit construction operation is simpler and more efficient, and the construction is safer and more stable. Moreover, after the construction of the bottom plate and each layer of structural floor slabs is completed, the column piles can be 100% recycled, truly achieving zero emissions, and realizing the effects of low-carbon, environmental protection and green construction.

[0104] In the above step S1, the prestressed prefabricated square piles 11 and prestressed square pile modification sections 13 with optimized designs are used. Figure 4As shown, the prestressed prefabricated square pile 11 has end embedded connectors 11-2 at the four corners of the upper and lower ends. The end embedded connectors 11-2 include angle steels at the four corners and square pile embedded end plates 11-3. The angle steels at the four corners have threaded sleeves. A prefabricated square pile reinforcement cage 11-1 is provided inside the prestressed prefabricated square pile 11. The upper and lower ends of the main reinforcement of the prefabricated square pile reinforcement cage 11-1 are respectively fixed to the upper and lower square pile embedded end plates 11-3, and the whole is poured with concrete to form a prefabricated square pile concrete 11-6. The prestressed prefabricated square pile 11 has high structural strength and can be directly statically pressed into the soil. The prefabricated square pile connector 12 is composed of four angle steels for connecting to the end embedded connectors 11-2. The angle steels are used to connect adjacent prestressed prefabricated square piles 11. The connection is firm and easy to recycle and disassemble. As shown Figure 5 As shown, the lower end of the prestressed square pile modified section 13 has a modified section lower end embedded screw sleeve 13-4 for connecting to the prefabricated square pile connector 12, and the upper end of the prestressed square pile modified section 13 has a modified section upper end connecting angle steel 13-8 for connecting to the lower end of the lattice column 21. The modified section upper end connecting angle steel 13-8 is formed by extending upward from the modified section angle steels 13-1 at the four corners of the prestressed square pile modified section 13, and adjacent modified section angle steels 13-1 are fixedly connected by a modified section reinforcement plate 13-2. The upper and lower ends of the prestressed square pile modified section 13 are also provided with a modified section embedded end plate 13-5, and a modified section steel bar cage 13-3 is provided inside the prestressed square pile modified section 13. The modified section steel bar cage 13-3 is fixedly connected to the upper and lower modified section embedded end plates 13-5, and the entire modified section concrete 13-7 is cast with concrete. When the lattice column 21 is connected through the prestressed square pile modification section 13, the lower end of the prestressed square pile modification section 13 is connected to the adjacent prestressed prefabricated square pile 11 through the prefabricated square pile connector 12, and the upper end of the prestressed square pile modification section 13 is connected to the adjacent lattice column 21 through the modification section upper end connecting angle steel 13-8. The above-mentioned prestressed prefabricated square pile 11 and prestressed square pile modification section 13 are adopted to ensure the connection accuracy and strength, and the angle steel structure is used for connection, the connection operation is simple, and the connection is firm and reliable.

[0105] Since this construction method can achieve 100% recovery of column piles, sensors such as stress monitors, displacement monitors and axial force detectors can be built into the prestressed square pile section 100 to monitor the deformation of the foundation pit. Specifically, in the prestressed square pile section 100, at least one of the prestressed prefabricated square pile 11 and the prestressed square pile modification section 13 has a built-in sensor. The built-in sensor includes a stress monitor, a displacement monitor and an axial force detector. The built-in sensor is connected to the background monitoring system through a wireless communication module. The built-in sensor can be reused after the column piles are recovered, and the full-section monitoring of the foundation pit can be achieved in conjunction with the background monitoring system. The background monitoring system is also connected to the self-servo hydraulic converter 24. The background monitoring system can have a built-in artificial intelligence AI algorithm. The background monitoring system controls the output pressure of the self-servo hydraulic converter 24 according to the foundation pit deformation obtained by the built-in sensor monitoring, effectively suppressing the foundation pit deformation and controlling the foundation pit deformation to the best. Figure 4 and Figure 5 As shown, a first built-in sensor 11-5 can be embedded in the prestressed prefabricated square pile 11, and a second built-in sensor 13-6 can be embedded in the prestressed square pile modification section 13. The first built-in sensor 11-5 and the second built-in sensor 13-6 can transmit data with the background monitoring system through a 5G signal meter.

[0106] In the above step S2, if Figure 7 As shown, the above-mentioned steel pallet 25 includes a pallet body 25-1 and support ribs 25-3 welded to the lower part of the pallet body 25-1. The pallet body 25-1 is a disc structure. The pallet body 25-1 is provided with mounting holes 25-2 corresponding to the position and size of the above-mentioned modified section upper end connecting angle steel 13-8. After the prestressed square pile modified section 13 and the prestressed prefabricated square pile 11 are pressed into the soil, the steel pallet 25 is sleeved on the modified section upper end connecting angle steel 13-8 of the prestressed square pile modified section 13. At this time, the support ribs 25-3 can fit with the corresponding outer wall of the modified section upper end connecting angle steel 13-8, thereby improving the installation stability of the steel pallet 25 and playing a certain role in cutting the soil when pressed into the soil. The pallet body 25-1 enlarges the outer edge size of the prestressed square pile modified section 13, and the size of the casing pile driver 300 is adapted to the pallet body 25-1, as shown in FIG. Fig.13 As shown, during construction, the casing pile driver 300 can be sleeved on the outside of the lattice column 21, and the lower end of the casing pile driver 300 is against the steel tray 25 to transmit pressure.

[0107] In the above step S3, refer to Fig. 20As shown, the self-servo hydraulic converter 24 comprises a hydraulic converter main box 24-1, a detachable converter connecting plate 24-2, a hydraulic jack connecting plate 24-3, a hydraulic jack cylinder sleeve 24-4 and a hydraulic jack oil cylinder 24-5. The hydraulic converter main box 24-1 is a rectangular structure. The detachable converter connecting plate 24-2 is respectively installed on the upper and lower end surfaces of the hydraulic converter main box 24-1 for connecting with the upper and lower adjacent lattice columns 21. Specifically, during installation, each detachable converter can be first connected to the lattice column 21. The converter connecting plate 24-2 is removed, and the main hydraulic converter housing 24-1 is placed between the upper and lower lattice columns 21. Then, the main hydraulic converter housing 24-1 is connected to the connection parts of the upper and lower lattice columns 21 by using the partially detachable converter connecting plate 24-2. After that, each time an external expansion connector 23-1 is removed, the main hydraulic converter housing 24-1 and the lattice column 21 are connected by using the detachable converter connecting plate 24-2, and the self-servo hydraulic converter 24 gradually replaces the lattice column connection section 22. The above-mentioned hydraulic jack connecting plates 24-3 are fixedly mounted on the four sides of the main hydraulic converter housing 24-1, and each hydraulic jack connecting plate 24-3 is provided with a set of hydraulic jack cylinder sleeves 24-4 and hydraulic jack oil cylinders 24-5. The telescopic directions of the four sets of hydraulic jack oil cylinders 24-5 are arranged in a "cross" shape, and the axial force compensation of each hydraulic jack oil cylinder 24-5 can be independently controlled. In order to facilitate the power supply and communication of the first built-in sensor 11-5 and the second built-in sensor 13-6, in the above-mentioned self-servo hydraulic converter 24, in addition to the hydraulic pipeline 24-6 for controlling the hydraulic jack cylinder 24-5, there is also a sensor connecting pipeline 24-7 to facilitate the line connection of the built-in sensors.

[0108] like Fig.21As shown, a beam connecting plate 43 is fixed to one end of the support beam 400 in this embodiment, and a positioning hole 44 matching the hydraulic jack cylinder 24-5 is provided on the beam connecting plate 43; the hydraulic jack connecting plate 24-3 and the beam connecting plate 43 are both "I"-shaped structures. When the support beam 400 is connected to the self-servo hydraulic converter 24, the telescopic end of the hydraulic jack cylinder 24-5 is inserted into the positioning hole 44 of the support beam 400, and a connecting screw for preventing falling is also provided between the hydraulic jack connecting plate 24-3 and the beam connecting plate 43, and there is axial activity margin between the connecting screw and the corresponding hydraulic jack connecting plate 24-3 and / or the beam connecting plate 43. That is to say, the connecting screw is not fixedly connected to the hydraulic jack connecting plate 24-3 and the beam connecting plate 43 in its axial direction. A movable connecting hole 24-3a is provided on the hydraulic jack connecting plate 24-3, and a corresponding through hole is also provided on the beam connecting plate 43. The connecting screw is sequentially inserted into the through hole of the beam connecting plate 43 and the movable connecting hole 24-3a of the hydraulic jack connecting plate 24-3. When the hydraulic jack cylinder 24-5 is extended and retracted to automatically compensate for the axial force, the hydraulic jack connecting plate 24-3 and the beam connecting plate 43 can move axially relative to each other. The self-servo hydraulic converter 24 can automatically compensate for the axial force of the supporting beam 400, and can effectively prevent the supporting beam 400 from accidentally falling, thereby ensuring construction safety. The supporting beam 400 can adopt existing steel pipe beams or concrete beams, etc. Specifically in this embodiment, the supporting beam 400 adopts a prestressed concrete support column 41, and the end of the prestressed concrete support column 41 also has a pre-embedded end connector 42, which is convenient for fixed connection with the beam connecting plate 43.

[0109] In the above step S5, the above lifting equipment includes a balanced vertical hydraulic jack 500, referring to Fig.23 As shown, the prestressed prefabricated square pile 11, the prestressed square pile modification section 13 and the lattice column 21 at the bottom are provided with lifting holes for matching with the balanced vertical hydraulic jack 500 at intervals in the vertical direction. Figure 4Taking the prestressed prefabricated square pile 11 as an example, there is a transversely arranged embedded sleeve 11-4 in the prestressed prefabricated square pile 11, and the above-mentioned extraction hole can be formed on the prestressed prefabricated square pile 11 by using the embedded sleeve 11-4. The extraction hole on the prestressed square pile modification section 13 can also be made in the same way; the extraction hole on the lattice column 21 can be set on its lattice column plate 21-2, or the gap between adjacent lattice column plates 21-2 can be used as the extraction hole. When pulling out, the balanced vertical hydraulic jack 500 is placed on the bottom plate of the foundation pit and connected to the extraction hole, and the balanced vertical hydraulic jack 500 is used to provide an upward extraction force to gradually pull out the column pile upward, so that the extraction and recovery of the column pile is more convenient and quick, and the extraction operation is safe and reliable; and the balanced vertical hydraulic jack 500 is installed on the bottom plate, which can prevent damage to the bottom plate during the extraction process.

[0110] Specific reference Fig.24 and Fig.25 As shown, the above-mentioned balanced vertical hydraulic jack 500 has two left and right parts with symmetrical structures, both of which include a semi-ring fixed seat 51, a fixed plate 52, a hydraulic cylinder 53, a lifting slide 54 and a pushing rod 55. The fixed plate 52 is arranged at the lower part of the semi-ring fixed seat 51, the hydraulic cylinder 53 is fixed on the fixed plate 52, the lifting slide 54 is slidably arranged on the semi-ring fixed seat 51 up and down, and is connected to the driving end of the hydraulic cylinder 53, and the pushing rod 55 is horizontally fixed on the lifting slide 54; in order to ensure the lifting stability of the lifting slide 54, a slide groove 51-1 is provided on the side wall of the semi-ring fixed seat 51, and the lifting slide 54 is slidably installed in the slide groove 51-1. The left and right half ring fixing seats 51 can be docked to form an annular seat that is embracing the column pile, and the left and right push rods 55 can be axially docked and inserted into the corresponding lifting holes, and the lifting and recovery of the column pile can be performed by using the pushing force generated by the hydraulic cylinder 53. There are also locking holes 51-2 at the two side ends of the half ring fixing seat 51. After the left and right half ring fixing seats 51 are docked, the two half ring fixing seats 51 can be fixed by bolts and other locking parts. In addition, a larger base can be provided at the bottom of the half ring fixing seat 51 to increase the contact area with the bottom plate. The balanced vertical hydraulic jack 500 adopts a two-petal combination structure, and uses two sets of symmetrical hydraulic cylinders and push rods to push and pull the column pile, which ensures the balance of the pulling force and realizes the vertical pulling of the column pile.

[0111] [Example 2]

[0112] The basic structure and working principle of the fully recycled prestressed square pile plus lattice column combined column pile construction method of this embodiment are the same as those of Embodiment 1, except that:

[0113] like Fig.26 and Fig. 27As shown, in this embodiment, the lattice column 21 in step S2 is a concrete lattice column 21B, and the concrete lattice column 21B includes a steel lattice column body welded by a lattice column angle steel 21-1 and a lattice column tie plate 21-2, and reinforced concrete 21-5 poured and filled in the steel lattice column body. The static pressure equipment 700 directly hugs and presses the concrete lattice column 21B to press the prestressed square pile segment 100 and the lattice column 21 into the soil to the designed elevation. The concrete lattice column design can make the lattice column have radial pressure bearing capacity, and then can achieve the effect of directly hugging and pressing into the soil. For deep foundation pits, the construction is simpler and more convenient.

[0114] like Fig. 27 As shown, the main body of the steel lattice column has the same structure as the steel lattice column 21A of the above-mentioned embodiment 1, except that it has reinforced concrete 21-5, and steel fibers can be added to the reinforced concrete 21-5 to further improve the compressive strength of the concrete lattice column 21B. Due to the supporting effect of the reinforced concrete 21-5, the entire concrete lattice column 21B can be directly pressed into the soil by a static press, without the need to use a casing pile driver, and the construction is simpler and more convenient.

[0115] [Example 3]

[0116] The basic structure and working principle of the fully recycled prestressed square pile plus lattice column combined column pile construction method of this embodiment are the same as those of Embodiment 1, except that:

[0117] like Figures 28 to 30 As shown, in this embodiment, the lattice column 21 in step S2 is a reinforced steel plate lattice column 21C, which includes a steel lattice column body welded by a lattice column angle steel 21-1 and a lattice column tie plate 21-2, and a reinforced steel sleeve 21-6 sleeved and fixed in the steel lattice column body. The outer wall of the reinforced steel sleeve 21-6 is also fixed with a reinforced side plate 21-7 located between adjacent lattice column angle steels 21-1. The static pressure device 700 directly hugs and presses the reinforced steel plate lattice column 21C to press the prestressed square pile segment 100 and the lattice column 21 into the soil to the designed elevation. The use of the reinforced steel plate lattice column design can make the lattice column have radial pressure bearing capacity, and thus can achieve the effect of directly hugging and pressing into the soil. For deep foundation pits, the construction is simpler and more convenient.

[0118] Reference Fig.30As shown, the main body of the steel lattice column has the same structure as the steel lattice column 21A of the above-mentioned embodiment 1, and the reinforcing steel sleeve 21-6 is a square steel pipe, and a reinforcing side plate 21-7 is welded on its outer wall. After the reinforcing steel sleeve 21-6 is installed in the main body of the steel lattice column, it can play a supporting role to it and improve its compressive resistance. Due to the supporting role of the reinforcing steel sleeve 21-6 and the reinforcing side plate 21-7, the entire reinforced steel plate lattice column 21C can be directly pressed into the soil using a static press, without the need to use a casing pile driver, and the construction is simpler and more convenient.

[0119] The fully recyclable prestressed square pile plus lattice column combined column pile construction method of the present invention utilizes prestressed square piles as the lower section of the column piles, and is organically combined with the lattice columns, and can be pressed into the designed elevation by static pressure equipment, and has the advantages of low construction cost, high construction efficiency and no pollution. By pressing the column piles into the soil as a whole, excavating the foundation pit soil layer by layer, and supporting the concrete supports and surrounding purlins around the foundation pit layer by layer with self-servo hydraulic converters and supporting beams, the foundation pit construction operation is simpler and more efficient, and the construction is safer and more stable. Moreover, after the construction of the bottom plate and each layer of structural floor slabs is completed, the column piles can be 100% recycled, truly achieving zero emissions, and realizing the effects of low-carbon, environmentally friendly and green construction.

[0120] Since this construction method can achieve 100% recovery of column piles, sensors such as stress monitors, displacement monitors and axial force detectors can be built into the prestressed square pile sections. Together with the background monitoring system, full-section monitoring of the foundation pit can be achieved. The background monitoring system can also control the output pressure of the self-servo hydraulic converter based on the foundation pit deformation obtained by the built-in sensors, thereby effectively suppressing the deformation of the foundation pit.

[0121] 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. A construction method for fully recycled prestressed square piles and lattice columns combined column piles, characterized in that: The construction steps include: S1. Using a static pressure device (700), a prestressed square pile segment (100) is pressed into a foundation pit soil (602); the prestressed square pile segment (100) comprises a plurality of sections of prestressed prefabricated square piles (11), and two adjacent sections of the prestressed prefabricated square piles (11) are connected via a prefabricated square pile connector (12); the upper end of the prestressed prefabricated square pile (11) located at the uppermost part is also connected to a prestressed square pile modification section (13) via a prefabricated square pile connector (12); S2, installing a lattice column segment (200) on the upper end of the prestressed square pile segment (100), and using a static pressure device (700) to press the lattice column segment (200) and the prestressed square pile segment (100) together to a designed elevation; the lattice column segment (200) comprises a plurality of lattice column sections (21), two adjacent lattice column sections (21) are connected via a detachable lattice column connecting section (22), and the lattice column (21) at the bottom is connected to a prestressed square pile modification section (13); S3, excavating the foundation pit soil (602) layer by layer, and sequentially constructing various layers of concrete supports (603) and surrounding purlins around the foundation pit; after excavating the surface foundation pit soil (602), installing a self-servo hydraulic converter (24) having a four-way servo automatic compensation hydraulic mechanism on the upper end of the lattice column (21) located at the uppermost part, and connecting the self-servo hydraulic converter (24) of the adjacent column piles and the self-servo hydraulic converter (24) with the first layer of concrete supports (603) by using a supporting crossbeam (400); then excavating the lower soil layer layer by layer, using the self-servo hydraulic converter (24) to replace the corresponding lattice column connecting section (22), and similarly connecting the self-servo hydraulic converter (24) of the adjacent column piles and the self-servo hydraulic converter (24) with various layers of concrete supports (603) by using a supporting crossbeam (400); S4, constructing the bottom plate (604) and the structural floors (605) of each layer in sequence from the bottom of the foundation pit upwards, with gaps for lifting and recovering the column piles being left between the bottom plate (604) and the structural floors (605) of each layer and the lattice column pile segments (200); S5. After the bottom plate (604) and the structural floor plates (605) of each layer have reached the designed strength, the column piles are pulled out and dismantled by using the pulling equipment, and the prestressed square pile segments (100) and the lattice column segments (200) are recovered.

2. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1 is characterized in that: Step S1 also includes the following sub-steps: S1-1, after the pile position is determined, the first section of the prestressed prefabricated square pile (11) is pressed into the foundation pit soil (602) by using the static pressure device (700), and then the next section of the prestressed prefabricated square pile (11) is hoisted and connected to the upper end of the prestressed prefabricated square pile (11) that has been pressed into the foundation pit soil (602) through the prefabricated square pile connector (12), and the static pressure device (700) is continued to perform the pile pressing operation; after the static pressure of all the prestressed prefabricated square piles (11) is completed, the upper end of the uppermost prestressed prefabricated square pile (11) is connected to the prestressed square pile modification section (13) through the prefabricated square pile connector (12), and the static pressure device (700) is continued to perform the pile pressing operation on the prestressed square pile modification section (13); S1-2, installing a conversion connection block (701a) at the lower end of the square pile driver (701), hoisting the square pile driver (701) and docking it with the upper end of the prestressed square pile modification section (13) through the conversion connection block (701a), and using the static pressure device (700) to hold and press the square pile driver (701) until the prestressed square pile segment (100) is pressed to the designed depth.

3. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1 or 2, characterized in that: The prestressed prefabricated square pile (11) is provided with end embedded connectors (11-2) at the four corners of the upper and lower ends; the prefabricated square pile connector (12) is composed of four angle steels for connecting with the end embedded connectors (11-2); the lower end of the prestressed square pile modification section (13) is provided with a modification section lower end embedded screw sleeve (13-4) for connecting with the prefabricated square pile connector (12); the upper end of the prestressed square pile modification section (13) is provided with a modification section upper end connecting angle steel (13-8) for connecting with the lower end of a lattice column (21).

4. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1 is characterized in that: In step S2, the lattice column (21) is a steel lattice column (21A) or a concrete lattice column (21B) or a reinforced steel plate lattice column (21C), wherein: The steel lattice column (21A) is welded from a lattice column angle steel (21-1) and a lattice column tie plate (21-2); The concrete lattice column (21B) comprises a steel lattice column body welded from a lattice column angle steel (21-1) and a lattice column tie plate (21-2), and reinforced concrete (21-5) poured and filled in the steel lattice column body; The reinforced steel plate lattice column (21C) comprises a steel lattice column body welded from a lattice column angle steel (21-1) and a lattice column tie plate (21-2), and a reinforced steel sleeve (21-6) sleeved and fixed inside the steel lattice column body, and a reinforced side plate (21-7) located between adjacent lattice column angle steels (21-1) is also fixed on the outer side wall of the reinforced steel sleeve (21-6).

5. The construction method of fully-recoverable prestressed square pile plus lattice column combined column pile according to claim 4 is characterized in that: When the lattice column (21) is a steel lattice column (21A), a pulley stopper (21-4) is further provided on the lattice column plate (21-2) of the steel lattice column (21A), a steel tray (25) is installed on the top of the prestressed square pile modification section (13), the steel lattice column (21A) is connected to the prestressed square pile modification section (13), and a casing pile driver (300) is sleeved on the outer side of the steel lattice column (21A). ), the pulley stopper (21-4) is distributed along the inner wall of the casing pile driver (300) and can roll up and down relative to the inner wall of the casing pile driver (300), the lower end of the casing pile driver (300) is abutted against the steel tray (25), and the static pressure device (700) presses the prestressed square pile segment (100) and the steel lattice column (21A) into the soil to the designed elevation through the casing pile driver (300).

6. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 4 is characterized in that: When the lattice column (21) is a concrete lattice column (21B) or a reinforced steel plate lattice column (21C), the static pressure device (700) directly holds and presses the concrete lattice column (21B) or the reinforced steel plate lattice column (21C) to press the prestressed square pile segment (100) and the lattice column (21) together into the soil to the designed elevation.

7. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1 is characterized in that: In step S3, when the self-servo hydraulic converter (24) replaces the corresponding lattice column connection section (22), the upper and lower adjacent lattice columns (21) are temporarily connected through a temporary converter (23), and the temporary converter (23) is composed of four outward expansion connecting members (23-1). When the lattice column connection section (22) is removed, the four outward expansion connecting members (23-1) can gradually replace the lattice column connection section (22) to connect the upper and lower adjacent lattice columns (21), and an enlarged space for installing the self-servo hydraulic converter (24) is formed between the four outward expansion connecting members (23-1); when installing the self-servo hydraulic converter (24), the four outward expansion connecting members (23-1) are removed one by one in sequence.

8. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1 is characterized in that: In step S3, the self-servo hydraulic converter (24) comprises a hydraulic converter main box (24-1), a detachable converter connecting plate (24-2), a hydraulic jack connecting plate (24-3), a hydraulic jack cylinder sleeve (24-4) and a hydraulic jack oil cylinder (24-5), wherein the hydraulic converter main box (24-1) is a rectangular structure, the detachable converter connecting plate (24-2) is respectively mounted on the upper and lower end surfaces of the hydraulic converter main box (24-1) and is used to connect with upper and lower adjacent lattice columns (21), the hydraulic jack connecting plates (24-3) are respectively fixedly mounted on four side surfaces of the hydraulic converter main box (24-1), and each of the hydraulic jack connecting plates (24-3) is provided with a group of hydraulic jack cylinder sleeves (24-4) and hydraulic jack oil cylinders (24-5). cylinder (24-5); a beam connecting plate (43) is fixed to one end of the supporting beam (400), and a positioning hole (44) is provided on the beam connecting plate (43) for matching with the hydraulic jack cylinder (24-5); the hydraulic jack connecting plate (24-3) and the beam connecting plate (43) are both "I"-shaped structures, and when the supporting beam (400) is connected to the self-servo hydraulic converter (24), the telescopic end of the hydraulic jack cylinder (24-5) is inserted into the positioning hole (44) of the supporting beam (400), and a connecting screw for preventing falling is also provided between the hydraulic jack connecting plate (24-3) and the beam connecting plate (43), and an axial movable margin is provided between the connecting screw and the corresponding hydraulic jack connecting plate (24-3) and / or the beam connecting plate (43).

9. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1, characterized in that: In the prestressed square pile segment (100), at least one of the prestressed prefabricated square pile (11) and the prestressed square pile modification section (13) has a built-in sensor, the built-in sensor includes a stress monitor, a displacement monitor and an axial force detector, the built-in sensor is connected to a background monitoring system through a wireless communication module; the background monitoring system is also connected to a self-servo hydraulic converter (24), and the background monitoring system controls the output pressure of the self-servo hydraulic converter (24) according to the foundation pit deformation obtained by monitoring the built-in sensor.

10. The method for constructing fully-recoverable prestressed square piles and lattice columns combined column piles according to claim 1, characterized in that: In step S5, the lifting and pulling equipment includes a balanced vertical hydraulic jack (500), and lifting and pulling holes that match the balanced vertical hydraulic jack (500) are reserved at intervals in the up-down direction on the prestressed prefabricated square pile (11), the prestressed square pile modification section (13) and the lattice column (21) located at the bottom. The balanced vertical hydraulic jack (500) has two symmetrical left and right parts, and both the left and right parts include a semi-ring fixed seat (51), a fixed plate (52), a hydraulic cylinder (53), a lifting slide (54) and a push rod (55). The fixed plate (52) is provided with At the lower part of the semi-ring fixing seat (51), the hydraulic cylinder (53) is fixed on the fixing plate (52), the lifting slide (54) is slidably arranged on the semi-ring fixing seat (51) and connected to the driving end of the hydraulic cylinder (53), and the pushing rod (55) is horizontally fixed on the lifting slide (54); the left and right parts of the semi-ring fixing seat (51) can be connected to form an annular seat that is engaged with the column pile, and the left and right parts of the pushing rod (55) can be axially connected and inserted into the corresponding lifting and pulling holes, and the lifting and pulling recovery of the column pile is carried out by using the pushing force generated by the hydraulic cylinder (53).

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