Hollow interlayer concrete filled steel tube stiffening hybrid energy pile structure and construction method

Abstract

The invention relates to the field of ground source heat pumps, in particular to a hollow interlayer concrete-filled steel tube stiffening hybrid energy pile structure and a construction method.The pile structure comprises a core hollow interlayer concrete-filled steel tube member which comprises an inner steel tube and an outer steel tube which are concentrically arranged, and core concrete is poured between the inner steel tube and the outer steel tube; the externally-wrapped reinforced concrete member comprises a reinforcement cage and externally-wrapped concrete, the reinforcement cage is bound to the outer side of the outer steel pipe, a geotextile bag is arranged on the periphery of the reinforcement cage, and the externally-wrapped concrete is formed by pouring the geotextile bag; the heat pump exchange pipe comprises a heat pump exchange spiral pipe and a heat pump exchange straight pipe which are communicated with each other, the heat pump exchange spiral pipe is arranged around the reinforcement cage, and the heat pump exchange straight pipe is laid in the hollow area of the inner steel pipe. The hollow interlayer concrete-filled steel tube stiffening mixed pile technology and the ground source heat pump technology are combined, the additionally-arranged externally-wrapped reinforced concrete member can provide high bearing capacity, and the corrosion resistance of the core hollow interlayer concrete-filled steel tube member and the heat pump exchange system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ground source heat pumps, and in particular to a hollow sandwich steel tube concrete reinforced hybrid energy pile structure and a construction method. Background Art

[0002] Geothermal heat pump technology is an environmentally friendly air conditioning technology that uses shallow geothermal resources to achieve "warm in winter and cool in summer" inside buildings. Since the stratum or groundwater temperature in the area surrounding the geothermal hotspot usually remains almost constant throughout the year, by laying a geothermal exchange system and connecting it to the interior of the building, it can achieve the effect of cooling the room in summer and heating in winter, relying on renewable geothermal energy to establish a set of efficient, stable and environmentally friendly air conditioning circulation system. The energy pile structure is a new type of pile structure that uses the pile body of building facilities to lay the geothermal exchange system to achieve efficient development of geothermal resources. Since the pile foundation and the heat exchange system are constructed together, it can greatly reduce the drilling cost while achieving stable and safe geothermal exchange with a smaller underground space occupancy rate.

[0003] In some areas, due to the highly developed karst landforms, a large amount of groundwater near deep geothermal sources will flow out through karst fissures and pipes and eventually flow into shallow aquifers, forming abundant shallow geothermal resources. However, due to the highly developed karst pipes in the relevant areas, it is costly and difficult to fully realize the consolidation grouting method alone. The geological structure makes it impossible to use conventional methods to cast steel-concrete energy piles to collect geothermal resources. The proposal of a new energy pile structure that can utilize geothermal resources in karst areas is of great significance for the development of renewable clean energy. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing steel tube concrete structure energy pile in the prior art, that is, it is difficult to construct in karst developed areas and the relatively weak corrosion resistance when encountering underground aquifers around geothermal collection points, and to provide a hollow sandwich steel tube concrete reinforced hybrid energy pile structure and construction method.

[0005] In a first aspect, the present invention provides a hollow sandwich steel tube concrete reinforced hybrid energy pile structure, comprising

[0006] The core hollow sandwich steel tube concrete component comprises an inner steel tube and an outer steel tube arranged concentrically, and core concrete is poured between the inner steel tube and the outer steel tube;

[0007] An outer-wrapped reinforced concrete component includes a steel cage and outer-wrapped concrete, wherein the steel cage is tied to the outside of the outer steel pipe, a geotextile bag is arranged outside the steel cage, and the outer-wrapped concrete is formed by pouring the geotextile bag;

[0008] The heat pump exchange tube comprises a heat pump exchange spiral tube and a heat pump exchange straight tube which are interconnected. The heat pump exchange spiral tube is arranged around the steel cage, and the heat pump exchange straight tube is laid in the hollow area of ​​the inner steel tube.

[0009] Preferably, the steel cage is formed by longitudinal bars and stirrups tied together with the heat pump exchange spiral tube as a frame.

[0010] Preferably, the inner steel pipe and the outer steel pipe are both circular steel pipes.

[0011] Preferably, the inner steel tube and the outer steel tube are both polygonal steel tubes.

[0012] Preferably, one of the inner steel pipe and the outer steel pipe is a circular steel pipe, and the other is a polygonal steel pipe.

[0013] Preferably, the polygonal steel pipe includes a square steel pipe, a rectangular steel pipe, a regular hexagonal steel pipe and a regular octagonal steel pipe.

[0014] In a second aspect, the present invention provides a construction method of a hollow sandwich steel tube concrete reinforced hybrid energy pile structure, which is used to construct any of the above-mentioned hollow sandwich steel tube concrete reinforced hybrid energy pile structures, comprising the following steps:

[0015] S1: Place a heat pump exchange spiral tube on the outside of the outer steel tube, place a heat pump exchange straight tube on the inside of the inner steel tube, and connect the heat pump exchange spiral tube and the heat pump exchange straight tube;

[0016] S2: pouring core concrete between the inner steel tube and the outer steel tube to form a core hollow sandwich steel tube concrete component;

[0017] S3: Tie the outer side of the outer steel pipe to form a steel cage;

[0018] S4: Put the steel cage and the core hollow sandwich steel tube concrete component into the geotextile bag, tie up the upper and lower ends of the geotextile bag, and insert the grouting pipe into the bag;

[0019] S5: hoisting the geotextile bag containing the steel cage and the core hollow sandwich steel tube concrete component to the designated position of the drilling hole;

[0020] S6: Concrete is injected into the grouting pipe to form an externally-wrapped reinforced concrete component.

[0021] Preferably, in S3, the heat pump exchange spiral tube is used as a frame to place longitudinal reinforcement, and stirrups are tied to form a steel cage.

[0022] Preferably, in S4, the bottom of the grouting pipe is tightened with a blind head, and the top of the grouting pipe passes through a sleeve ring.

[0023] Preferably, the method further comprises S7: finishing the grouting, plugging the sleeve ring with a blind head, and unscrewing the grouting pipe.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention adopts hollow sandwich steel tube concrete reinforcement hybrid technology in pile design, which effectively improves the bearing capacity and deformation resistance of the structure under the influence of various types of geological disasters. Compared with the traditional steel tube concrete reinforcement hybrid structure, the hollow sandwich design can greatly reduce the amount of core concrete, and thin-walled steel tube materials can be used in some structures, effectively reducing construction costs.

[0026] 2. The present invention adds geotextile bags to the outside of the outer reinforced concrete to ensure that the overall structure can be smoothly constructed and form bearing capacity in karst areas, thereby realizing the possibility of building large and high-rise buildings in karst areas.

[0027] 3. The present invention combines the technology of hollow sandwich steel tube concrete reinforced mixed piles and the technology of ground source heat pumps. The added outer reinforced concrete components can effectively improve the corrosion resistance of the core hollow sandwich steel tube concrete components and the heat pump exchange system while providing a strong bearing capacity, thereby ensuring the safe and stable development of geothermal resources in karst development areas with abundant groundwater, and providing a set of efficient and energy-saving indoor cooling / heating air-conditioning systems for surface buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a vertical view of the energy pile structure described in an embodiment of the present invention.

[0029] Figure 2 Schematic diagram of a heat exchange system in an embodiment of the present invention.

[0030] Figure 3 A cross-sectional view of the energy pile structure described in an embodiment of the present invention (a square polygonal steel pipe is used as an example).

[0031] Markings in the figure:

[0032] 1—inner steel pipe, 2—core concrete, 3—outer steel pipe, 4—reinforcement cage, 401—longitudinal reinforcement, 402—hoop reinforcement, 5—outer concrete, 6—heat pump exchange tube, 601—heat pump exchange spiral tube, 602—heat pump exchange straight tube, 7—geotextile bag, 8—pile tip, 9—grouting pipe, 10—thrown ring, 11—blind end. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0034] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0035] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding devices / components / elements are within the error / deviation range, they can still achieve their functions in the scheme of the present invention.

[0036] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0037] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0038] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0039] Example 1

[0040] like Figure 1-3 As shown, a hollow sandwich steel tube concrete reinforced hybrid energy pile structure includes a core hollow sandwich steel tube concrete component, an outer reinforced concrete component and a heat pump exchange tube 6.

[0041] The core hollow sandwich steel tube concrete component includes an inner steel tube 1, core concrete 2 and an outer steel tube 3. The inner steel tube 1 and the outer steel tube 3 are concentrically arranged, and the core concrete 2 is poured between the inner steel tube 1 and the outer steel tube 3.

[0042] In an optional embodiment, the structural form of the core hollow sandwich steel tube concrete component mainly includes four types according to the distinction of the inner and outer steel tube cross-sections, such as Figure 3 As shown, they are: (a) standard circular steel pipe for the inner steel pipe and standard circular steel pipe for the outer steel pipe; (b) standard circular steel pipe for the inner steel pipe and polygonal steel pipe for the outer steel pipe; (c) polygonal steel pipe for the inner steel pipe and standard circular steel pipe for the outer steel pipe; (d) polygonal steel pipe for the inner steel pipe and polygonal steel pipe for the outer steel pipe. Polygonal steel pipes are selected according to the needs of different engineering designs, mainly square steel pipes, rectangular steel pipes, regular hexagonal steel pipes and regular octagonal steel pipes. For example, in the design of low-rise venues and residential buildings, square or rectangular outer steel pipes can be selected to facilitate welding at the beam-column nodes; in the design of high-rise buildings, large columns can be selected with glass curtain walls to ensure beauty, and regular hexagonal or regular octagonal outer steel pipes can be used to facilitate welding of columns and multiple beams at the same time.

[0043] The outer reinforced concrete component includes a steel cage 4 and outer concrete 5. The steel cage 4 is tied to the outside of the outer steel pipe 3 and poured to form the outer concrete 5. Specifically, a geotextile bag 7 can be arranged outside the steel cage 4, and the outer concrete 5 is poured through the geotextile bag 7.

[0044] The heat pump exchange tube 6 includes a heat pump exchange spiral tube 601 and a heat pump exchange straight tube 602 that are interconnected. The heat pump exchange spiral tube 601 is arranged around the steel cage 4, and is buried in the outer reinforced concrete 5 from the surface to the geothermal point. The heat pump exchange straight tube 602 is laid in the hollow area of ​​the inner steel pipe 1, and is a straight tube from the geothermal point to the surface. The hollow channel of the hollow sandwich steel tube concrete component is used to quickly exchange heat, which effectively reduces the loss of geothermal resources during the transmission process to the surface.

[0045] In an optional embodiment, the steel cage 4 is formed by longitudinal bars 401 and stirrups 402 tied together with the heat pump exchange spiral tube 601 as a frame. Thus, the heat pump exchange spiral tube 601 can be used as a steel cage frame to facilitate construction and save some stirrups, and can also ensure that the heat pump exchange system can fully exchange energy near the geothermal point.

[0046] The present invention adopts the hollow sandwich steel tube concrete reinforcement mixing technology in the pile design of large-scale building facilities, which effectively improves the bearing capacity and deformation resistance of the structure under the influence of various types of geological disasters. Specifically:

[0047] At present, a large number of studies on steel tube concrete columns have shown that, compared with reinforced concrete structures or pure steel tube structures, the application of steel tube concrete technology can enable steel components and concrete components to work together and give full play to the material properties, which can better avoid laminar tearing and delay local buckling of steel tubes while reducing material costs.

[0048] This example takes a large-span steel tube concrete structure tower in Zhoushan as the engineering background. By studying the mechanical properties of a single-leg circular steel tube concrete column with the same structure as the large-span tower and comparing it with a circular pure steel tube structure under the same axial compression bearing capacity standard, the technical effect of the steel tube concrete structure in large-scale engineering is analyzed and verified.

[0049] According to the Technical Standard for Steel Tube Concrete Hybrid Structures (GB / T 51446-2021), the calculation method for the design value of the axial compressive bearing capacity of a single-leg circular concrete-filled steel tube section is as follows:

[0050]

[0051] N c =f sc A sc

[0052]

[0053] f scy =(1.14+1.02ξ)f ck

[0054]

[0055] Where N u is the design value of the compressive stability bearing capacity of the single-leg chord section (N); is the axial compression stability coefficient; N c A is the design value of the compressive bearing capacity of the single-leg chord section (N); sc is the total cross-sectional area of ​​the single-leg chord (mm 2 );f scis the design value of axial compressive strength of concrete-filled steel tube section (N / mm 2 );f scy is the standard value of axial compressive strength of concrete-filled steel tube section (N / mm 2 ); γ sc is the partial coefficient of axial compressive strength of concrete-filled steel tube, which is taken as 1.20 in power tower; ξ is the constraint effect coefficient; f ck is the standard value of concrete axial compressive strength (N / mm 2 );f y is the yield strength of steel (N / mm 2 );A s is the cross-sectional area of ​​the steel pipe (mm 2 );A c is the cross-sectional area of ​​concrete in the steel tube (mm 2 ).

[0056] According to the "Steel Structure Design Standard" (GB 50017-2017), the calculation method for the design value of the axial compressive bearing capacity of a single-leg circular steel tube section is as follows:

[0057]

[0058] Where N is the design value of the compressive stability bearing capacity of the single-leg steel pipe section (N); f is the design value of the compressive strength of the steel material (N / mm2); A is the gross cross-sectional area of ​​the steel pipe (mm 2 ); k is the steel grade correction factor; is the stability factor of the steel tube axially compressed member, which is determined by the structural slenderness ratio and ε k control.

[0059] According to the actual situation of a large span tower in Zhoushan, Q355 seamless steel tube and C50 concrete materials are selected for verification of the steel tube concrete column and pure steel tube column. The yield strength and tensile strength of the steel tube refer to the "General Code for Steel Structure" (GB55006-2021), as shown in Table 1; the compressive strength of the concrete refers to the "Technical Regulations for the Design of Hollow Sandwich Steel Tube Concrete Towers for Transmission Lines" (Q / GDW 11136-2013), as shown in Table 2; the input parameters and verification results of the calculation model are shown in Table 3. In the assumed working conditions of the model, the axial compressive stability bearing capacity of the steel tube concrete column and the pure steel tube column is maintained at 1.2×105kN, and the cross-sectional size of the steel tube concrete column is selected as Φ1800×25mm with reference to the large span tower in Zhoushan. The calculation results show that under the condition of ensuring the same bearing capacity, the steel wall thickness of the steel tube concrete structure is reduced by 50% compared with the pure steel tube structure, and the cross-sectional area is reduced by 52%, the material cost is greatly reduced, and the structural advantage is obvious.

[0060] Table 1 Strength index of seamless steel pipe for structural design

[0061]

[0062] Table 2 Design value and standard value of concrete strength (N / mm 2 )

[0063]

[0064] Table 3 List of model parameter values ​​and calculation results

[0065]

[0066] The pile structure proposed in the present invention is based on bag grouting technology, and can be normally constructed and form bearing capacity in areas with highly developed karst. During the long-term operation of the structure in a complex geological environment, the external concrete component 5 can effectively improve the corrosion resistance of the overall structure. When bearing loads, the concrete and steel structure in various parts can work together, and the inner steel pipe 1, the core concrete 2 and the outer steel pipe 3 can better exert the material bearing capacity performance under mutual constraints, reducing the possibility of instability and buckling of the steel structure. Since the inner steel pipe 1 and the outer steel pipe 3 in the structure can be thin-walled steel pipe components, the longitudinal reinforcement 401 tied with the heat pump exchange spiral tube 601 as the frame can reduce the amount of stirrups 402, thereby greatly reducing the material cost. After determining the location of the geothermal point, the proposed new energy pile body can ignore obstacles such as caves and groundwater for construction, and use the outer heat pump exchange spiral tube 601 to fully exchange energy and transmit it to the surface with low loss through the heat pump exchange straight tube 602 in the hollow area, thereby realizing efficient utilization of geothermal resources in the karst area.

[0067] Example 2

[0068] A construction method of a hollow sandwich steel tube concrete reinforced hybrid energy pile structure, used for constructing a hollow sandwich steel tube concrete reinforced hybrid energy pile structure as described in any one of Embodiment 1, comprising the following steps:

[0069] S1: Place the heat pump exchange spiral tube 601 on the outside of the outer steel tube 3, place the heat pump exchange straight tube 602 on the inside of the inner steel tube 1, and connect the heat pump exchange spiral tube 601 and the heat pump exchange straight tube 602.

[0070] S2: pouring core concrete 2 between the inner steel tube 1 and the outer steel tube 3 to form a core hollow sandwich steel tube concrete component.

[0071] S3: Tie the outer side of the outer steel pipe 3 to form a steel cage 4; in the preferred solution, the heat pump exchange spiral tube 601 is used as a frame to place longitudinal reinforcement 401, tie the stirrups 402, and form a steel cage 4.

[0072] S4: insert the steel cage 4 and the core hollow sandwich steel tube concrete component into the geotextile bag 7, tie up the upper and lower ends of the geotextile bag 7, and insert the grouting pipe 9 into the bag; in the preferred solution, the bottom of the grouting pipe 9 is tightened with a blind head 11, and the top of the grouting pipe 9 passes through a collar 10. The collar 10 is preferably a plastic collar.

[0073] S5: Hanging the geotextile bag 7 containing the steel cage 4 and the core hollow sandwich steel tube concrete component to the designated position of the drilling hole.

[0074] S6: Concrete is injected into the grouting pipe 9 to form an outer reinforced concrete component.

[0075] S7: Finish grouting, use the blind head 11 to block the sleeve ring 10, and unscrew the grouting pipe 9.

[0076] In some embodiments, before constructing the core hollow sandwich steel tube concrete component, the method further includes:

[0077] Drill and collect core samples, analyze geological characteristics, and determine the size of the pile. For areas with strong karst development, drilling exploration should be carried out on each pile, and the pile and geotextile bag size with sufficient bearing capacity should be designed based on the rock composition, joint development, presence and size of caves, and type of cave fillings.

[0078] The types of inner steel tube 1 and outer steel tube 3 are selected according to the engineering requirements. Generally, if the structure needs to have a strong bearing capacity and deformation resistance, it is recommended to use a circular inner steel tube 1 and a circular outer steel tube 3 design; if the upper part of the structure needs to be welded with a beam structure, etc., it is recommended to use a polygonal outer steel tube 3 design.

[0079] The construction method described in the present invention can ensure that the overall structure can be smoothly constructed and form bearing capacity in karst areas, thereby realizing the possibility of constructing large and high-rise buildings in karst areas.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hollow sandwich steel tube concrete reinforced hybrid energy pile structure, characterized in that: include A core hollow sandwich steel tube concrete component comprises an inner steel tube (1) and an outer steel tube (3) which are arranged concentrically, and core concrete (2) is poured between the inner steel tube (1) and the outer steel tube (3); An outer-wrapped reinforced concrete component comprises a steel cage (4) and outer-wrapped concrete (5), wherein the steel cage (4) is tied to the outside of the outer steel pipe (3), a geotextile bag (7) is arranged on the periphery of the steel cage (4), and the outer-wrapped concrete (5) is formed by pouring the geotextile bag (7); The heat pump exchange tube (6) comprises a heat pump exchange spiral tube (601) and a heat pump exchange straight tube (602) which are interconnected, wherein the heat pump exchange spiral tube (601) is arranged around the steel cage (4), and the heat pump exchange straight tube (602) is laid in the hollow area of ​​the inner steel tube (1).

2. A hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 1, characterized in that: The steel cage (4) is formed by binding longitudinal bars (401) and stirrups (402) with the heat pump exchange spiral tube (601) as a frame.

3. The hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 1, characterized in that: The inner steel pipe (1) and the outer steel pipe (3) are both circular steel pipes.

4. The hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 1, characterized in that: The inner steel pipe (1) and the outer steel pipe (3) are both polygonal steel pipes.

5. The hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 1, characterized in that: One of the inner steel pipe (1) and the outer steel pipe (3) is a circular steel pipe, and the other is a polygonal steel pipe.

6. A hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 4 or 5, characterized in that: The polygonal steel pipe includes a square steel pipe, a rectangular steel pipe, a regular hexagonal steel pipe and a regular octagonal steel pipe.

7. A construction method for a hollow sandwich steel tube concrete reinforced hybrid energy pile structure, characterized in that: The method for constructing a hollow sandwich steel tube concrete reinforced hybrid energy pile structure as described in any one of claims 1 to 6 comprises the following steps: S1: placing a heat pump exchange spiral tube (601) on the outside of the outer steel tube (3), placing a heat pump exchange straight tube (602) on the inside of the inner steel tube (1), and connecting the heat pump exchange spiral tube (601) and the heat pump exchange straight tube (602); S2: pouring core concrete (2) between the inner steel tube (1) and the outer steel tube (3) to form a core hollow sandwich steel tube concrete component; S3: tying the outer side of the outer steel pipe (3) to form a steel cage (4); S4: inserting the steel cage (4) and the core hollow sandwich steel tube concrete component into the geotextile bag (7), tying the upper and lower ends of the geotextile bag (7), and inserting the grouting pipe (9) into the bag; S5: hanging and placing the geotextile bag (7) containing the steel cage (4) and the core hollow sandwich steel tube concrete component to the designated position of the drilling hole; S6: Concrete is injected into the grouting pipe (9) to form an outer reinforced concrete component.

8. The construction method of a hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 7, characterized in that: In the above-mentioned S3, the heat pump exchange spiral tube (601) is used as a frame to place longitudinal reinforcement (401), and the stirrups (402) are tied to form a steel cage (4).

9. The construction method of a hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 7, characterized in that: In S4, the bottom of the grouting pipe (9) is tightened with a blind head (11), and the top of the grouting pipe (9) passes through a sleeve ring (10).

10. The construction method of a hollow sandwich steel tube concrete reinforced hybrid energy pile structure according to claim 9, characterized in that: The process also includes S7: finishing the grouting, plugging the sleeve ring (10) with a plug (11), and screwing out the grouting pipe (9).

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