A structure and construction method of a hollow sandwich concrete-filled steel tube stiffened hybrid energy pile

Abstract

The present invention relates to the field of ground source heat pumps, and particularly to a structure and construction method of a hollow sandwich steel pipe concrete stiffened hybrid energy pile. The pile structure includes: a core hollow sandwich steel pipe concrete member, which includes an inner steel pipe and an outer steel pipe arranged concentrically, and core concrete is poured between the inner steel pipe and the outer steel pipe; an outer reinforced concrete member, which includes a steel reinforcement cage and outer concrete, the steel reinforcement cage is tied to the outside of the outer steel pipe, a geotextile bag is arranged around the steel reinforcement cage, and the outer concrete is formed by pouring through the geotextile bag; a heat pump exchange pipe, which includes a heat pump exchange spiral pipe and a heat pump exchange straight pipe that are interconnected, the heat pump exchange spiral pipe is arranged around the steel reinforcement cage, and the heat pump exchange straight pipe is laid in the hollow area of the inner steel pipe. The present invention combines the hollow sandwich steel pipe concrete stiffened hybrid pile technology and the ground source heat pump technology. The added outer reinforced concrete member can provide strong bearing capacity and improve the corrosion resistance of the core hollow sandwich steel pipe concrete member and the heat pump exchange system.

Description

Technical Field

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

[0002] The ground source heat pump technology is an environment-friendly air conditioning technology that realizes "warm in winter and cool in summer" inside buildings by utilizing shallow geothermal resources. Since the temperature of the formation or groundwater in the surrounding area of the geothermal point usually remains almost constant throughout the year, after laying a geothermal exchange system and connecting it to the inside of the building, it can play the role of cooling in summer and heating in winter for the indoor area, and establish a set of efficient, stable and environment-friendly air conditioning circulation system relying on renewable geothermal energy. The energy pile structure is a new pile structure that utilizes the pile body of a building facility to lay a geothermal exchange system to achieve efficient development of geothermal resources. Since the pile foundation and the heat exchange system are constructed together, it can significantly reduce the drilling cost while achieving stable and safe geothermal exchange with a small underground space occupancy rate.

[0003] In some areas, due to the highly developed karst landform, a large amount of groundwater near deep geothermal sources will flow out through karst fissures and pipelines and finally converge into the shallow aquifer, forming rich shallow geothermal resources. However, due to the highly developed karst pipelines in the relevant areas, if only relying on traditional means such as consolidated grouting, the cost is high and it is difficult to fully achieve. The geological structure makes it impossible to adopt conventional methods to pour and form an energy pile body of a steel-concrete structure to collect geothermal resources. Therefore, it is of great significance to develop a new energy pile structure that can utilize geothermal resources in karst areas for the development of renewable clean energy. Summary of the Invention

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

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

[0006] a core hollow sandwich steel tube concrete member, comprising 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 reinforced concrete member, comprising a steel reinforcement cage and outer concrete, the steel reinforcement cage is tied outside the outer steel tube, a geotextile bag is arranged around the steel reinforcement cage, and the outer concrete is poured through the geotextile bag;

[0008] The heat pump exchange pipe includes a heat pump exchange spiral pipe and a heat pump exchange straight pipe that are interconnected. The heat pump exchange spiral pipe is arranged around the steel reinforcement cage, and the heat pump exchange straight pipe is laid in the hollow area of the inner steel pipe.

[0009] Preferably, the steel reinforcement cage is formed by tying longitudinal bars and stirrups with the heat pump exchange spiral pipe as the framework.

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

[0011] Preferably, both the inner steel pipe and the outer steel pipe are polygonal steel pipes.

[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 for a hollow sandwich steel pipe concrete stiffened hybrid energy pile structure for constructing any one of the hollow sandwich steel pipe concrete stiffened hybrid energy pile structures, including the following steps:

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

[0016] S2: Pour core concrete between the inner steel pipe and the outer steel pipe to form a core hollow sandwich steel pipe concrete member;

[0017] S3: Tie a steel reinforcement cage outside the outer steel pipe;

[0018] S4: Put the steel reinforcement cage and the core hollow sandwich steel pipe concrete member into a geotextile bag, tie the upper and lower ends of the geotextile bag tightly, and insert a grouting pipe into the bag;

[0019] S5: Lift and place the geotextile bag containing the steel reinforcement cage and the core hollow sandwich steel pipe concrete member to the designated position of the drill hole;

[0020] S6: Inject concrete through the grouting pipe to form an outer reinforced concrete member.

[0021] Preferably, in S3, place longitudinal bars with the heat pump exchange spiral pipe as the framework and tie stirrups to form a steel reinforcement cage.

[0022] Preferably, in S4, screw a plug tightly at the bottom of the grouting pipe, and the top of the grouting pipe passes through the collar.

[0023] Preferably, it further includes S7: ending the grouting, blocking the collar with a plug, and screwing out the grouting pipe.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. In the pile body design of the present invention, the hollow sandwich steel tube concrete stiffening hybrid technology is adopted, which effectively improves the bearing capacity and deformation resistance of the structure under various types of geological disasters. Compared with the traditional steel tube concrete stiffening hybrid structure, the use of the hollow sandwich design can significantly reduce the amount of core concrete, and thin-walled steel tube materials can be used in some structures, effectively reducing the construction cost.

[0026] 2. By adding geotextile bags outside the reinforced concrete, the present invention ensures that the overall structure can be smoothly constructed and form bearing capacity in karst-developed areas, realizing the possibility of building large-scale and high-rise buildings in karst areas.

[0027] 3. The present invention combines the hollow sandwich steel tube concrete stiffening hybrid pile technology and the ground source heat pump technology. The added reinforced concrete component outside can effectively improve the corrosion resistance of the core hollow sandwich steel tube concrete component and the heat pump exchange system while providing strong bearing capacity, ensuring the safe and stable development of geothermal resources in karst-developed areas with rich groundwater, and providing an efficient and energy-saving indoor cooling / heating air conditioning system for surface buildings. Description of the Drawings

[0028] Figure 1 It is an elevation view of the energy pile structure described in the embodiment of the present invention.

[0029] Figure 2 It is a schematic diagram of the geothermal exchange system in the embodiment of the present invention.

[0030] Figure 3 It is a sectional view of the energy pile structure described in the embodiment of the present invention (taking a square steel tube as an example for the polygon steel tube).

[0031] Markings in the figure:

[0032] 1 - inner steel tube, 2 - core concrete, 3 - outer steel tube, 4 - steel reinforcement cage, 401 - longitudinal reinforcement, 402 - stirrup, 5 - outer concrete, 6 - heat pump exchange pipe, 601 - heat pump exchange spiral pipe, 602 - heat pump exchange straight pipe, 7 - geotextile bag, 8 - pile tip, 9 - grouting pipe, 10 - collar, 11 - plug. Detailed Embodiments

[0033] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented 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 expression terms indicating the orientation or positional relationship, such as "upper", "lower", "left", "right", "center", "inner", "outer", etc., are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / device / installation is in its usual use. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0035] In addition, for terms such as "horizontal", "vertical", "hanging", "parallel", etc., it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but it can be slightly inclined or have a deviation. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in directions such as "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still perform its function in the solution of the present invention.

[0036] In addition, for expressions such as "first", "second", "third", etc. in the terms, they are only used to distinguish the description of the same or similar components, and should not be construed as emphasizing or implying the relative importance of a specific component.

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

[0038] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, for the places where terms such as "set", "installed", "connected", "coupled", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. Such a connection can be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements.

[0039] Example 1

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

[0041] The core hollow sandwich steel tube concrete member 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 implementation manner, the structural form of the core hollow sandwich steel tube concrete member mainly includes four types according to the distinction of the cross-sections of the inner and outer steel tubes. As Figure 3 shown, they are respectively: (a) the inner steel tube is a standard circular steel tube, and the outer steel tube is a standard circular steel tube; (b) the inner steel tube is a standard circular steel tube, and the outer steel tube is a polygonal steel tube; (c) the inner steel tube is a polygonal steel tube, and the outer steel tube is a standard circular steel tube; (d) the inner steel tube is a polygonal steel tube, and the outer steel tube is a polygonal steel tube. The polygonal steel tubes are selected according to different engineering design requirements, mainly including square steel tubes, rectangular steel tubes, regular hexagon steel tubes, regular octagon steel tubes, etc. For example, in the design of low-rise stadiums and residential buildings, square or rectangular outer steel tubes can be selected to facilitate welding at the beam-column joints; in the design of high-rise buildings, large columns can be paired with glass curtain walls to ensure aesthetics, and regular hexagon or regular octagon outer steel tubes can be used to facilitate welding of the columns with multiple beam bodies at the same time.

[0043] The outer reinforced concrete member includes a steel reinforcement cage 4 and outer concrete 5. The steel reinforcement cage 4 is tied to the outside of the outer steel tube 3 and the outer concrete 5 is formed by pouring. Specifically, geotextile bags 7 can be arranged around the steel reinforcement cage 4, and the outer concrete 5 is formed by pouring through the geotextile bags 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 reinforcement cage 4 and is buried in the outer reinforced concrete 5 from the ground surface to the geothermal point; the heat pump exchange straight tube 602 is laid in the hollow area of the inner steel tube 1 and is straight from the geothermal point to the ground surface, and the hollow channel of the hollow sandwich steel tube concrete member is used for rapid heat exchange, effectively reducing the loss during the transmission of geothermal resources to the ground surface.

[0045] In an alternative embodiment, the steel reinforcement cage 4 is tied with longitudinal bars 401 and stirrups 402 with the heat pump exchange spiral pipe 601 as the framework. Thus, the heat pump exchange spiral pipe 601 can not only serve as the steel reinforcement cage framework to facilitate construction and save some stirrups, but also ensure that the heat pump exchange system can fully exchange energy near the geothermal point.

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

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

[0048] This example takes a large-span tower of a concrete-filled steel tube structure in Zhoushan as the engineering background. By studying the mechanical properties of a single-limb circular concrete-filled steel tube 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 application of the concrete-filled steel tube structure in large-scale projects is analyzed and verified.

[0049] According to the "Technical Standard for Concrete-Filled Steel Tube Hybrid Structures" (GB / T 51446-2021), the calculation method for the design value of the axial compression bearing capacity of a single-limb 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] In the formula, N u is the design value of the compressive stability bearing capacity of a single-limb chord section (N); is the coefficient of compressive stability; N c is the design value of the compressive bearing capacity of a single-limb chord section (N); A sc is the total cross-sectional area of a single-limb chord (mm 2 ); f scis the design value of the axial compressive strength of the concrete-filled steel tube section (N / mm 2 ); f scy is the standard value of the axial compressive strength of the concrete-filled steel tube section (N / mm 2 ); γ sc is the partial coefficient of the axial compressive strength of the concrete-filled steel tube. It is taken as 1.20 in the power tower; ξ is the confinement effect coefficient; f ck is the standard value of the axial compressive strength of the concrete (N / mm 2 ); f y is the yield strength of the steel (N / mm 2 ); A s is the cross-sectional area of the steel tube (mm 2 ); A c is the cross-sectional area of the concrete inside the steel tube (mm 2 ).

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

[0057]

[0058] In the formula, N is the design value of the compressive stability bearing capacity of a single-limb steel tube section (N); f is the design value of the compressive strength of the steel (N / mm2); A is the gross cross-sectional area of the steel tube (mm 2 ); ε k is the steel grade correction coefficient; is the stability coefficient of the axially compressed steel tube member, which is controlled by the slenderness ratio of the structure and ε k .

[0059] Both the concrete-filled steel tube column and the pure steel tube column are checked according to the actual situation of a large-span tower in Zhoushan, and Q355 seamless steel tubes and C50 concrete materials are selected. The yield strength and tensile strength of the steel are referred to the "General Code for Steel Structures" (GB55006-2021), as shown in Table 1; the compressive strength of the concrete is referred to the "Technical Regulations for the Design of Concrete-filled Steel Tube Towers with Hollow Interlayers in 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 compression stability bearing capacities of both the concrete-filled steel tube column and the pure steel tube column are maintained at 1.2×105 kN, and the cross-sectional dimensions of the concrete-filled steel tube column are 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 concrete-filled steel tube structure is reduced by 50% compared with the pure steel tube structure, the cross-sectional area is reduced by 52%, and the material cost is greatly reduced, with obvious structural advantages.

[0060] Table 1 Strength Indexes of Seamless Steel Tubes for Structural Design

[0061]

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

[0063]

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

[0065]

[0066] The pile structure proposed by the present invention is based on the bag grouting technology, and can be constructed normally 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 member 5 can effectively improve the corrosion resistance of the overall structure; when bearing loads, the concrete and steel structures in each part can work together, and the inner steel pipe 1, the core concrete 2 and the outer steel pipe 3 can better exert the bearing capacity performance of the materials under mutual restraint, reducing the possibility of buckling instability of the steel structure; since the inner steel pipe 1 and the outer steel pipe 3 in the structure can adopt thin-walled steel pipe members, tying the longitudinal reinforcement 401 with the heat pump exchange spiral pipe 601 as the framework can reduce the amount of stirrups 402, thus greatly reducing the material cost; after determining the geothermal point position, the proposed new energy pile can ignore obstacles such as karst caves and groundwater for construction, make full use of the heat pump exchange spiral pipe 601 on the outer side to exchange energy and transmit it to the ground surface with low loss through the heat pump exchange straight pipe 602 in the hollow area, realizing the efficient utilization of geothermal resources in karst areas.

[0067] Embodiment 2

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

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

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

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

[0072] S4: Insert the steel reinforcement cage 4 and the core hollow sandwich steel tube concrete member into the geotextile bag 7, tie the upper and lower ends of the geotextile bag 7 tightly, and insert the grouting pipe 9 into the bag. In a preferred embodiment, the bottom of the grouting pipe 9 is tightened with a plug 11, and the top of the grouting pipe 9 passes through the collar 10. The collar 10 is preferably a plastic collar.

[0073] S5: Lift and place the geotextile bag 7 containing the steel reinforcement cage 4 and the core hollow sandwich steel tube concrete member to the designated position of the borehole.

[0074] S6: Inject concrete through the grouting pipe 9 to form an outer reinforced concrete member.

[0075] S7: End the grouting, block the collar 10 with the plug 11, and remove the grouting pipe 9 by screwing it out.

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

[0077] Drill a hole and collect core samples to analyze the geological characteristics and determine the pile dimensions. In areas with strong karst development, borehole exploration should be carried out for each pile. According to the rock formation, joint development, presence and scale of karst caves, type of cave filling materials, etc., design the pile body and geotextile bag dimensions sufficient to form the bearing capacity.

[0078] Select the types of the inner steel tube 1 and the outer steel tube 3 according to the project needs. Generally, if the structure needs to have strong bearing capacity and resistance to deformation, it is recommended to use a circular inner steel tube 1 and a circular outer steel tube 3 for design; if welding processing is required between the upper part of the structure and the beam structure, etc., it is recommended to use a polygonal outer steel tube 3 for design.

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

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A structure of a hollow sandwich concrete-filled steel tube stiffened hybrid energy pile, characterized in that including a core hollow sandwich steel tube concrete member, including an inner steel tube (1) and an outer steel tube (3) arranged concentrically, and core concrete (2) is poured between the inner steel tube (1) and the outer steel tube (3); a reinforced concrete outer member, including a steel reinforcement cage (4) and outer concrete (5), and the steel reinforcement cage (4) is tied to the outside of the outer steel tube (3); a heat pump exchange pipe (6), including a heat pump exchange spiral pipe (601) and a heat pump exchange straight pipe (602) that are connected to each other; the steel reinforcement cage (4) is tied by longitudinal bars (401) and stirrups (402) with the heat pump exchange spiral pipe (601) as a framework, a geotextile bag (7) is arranged around the steel reinforcement cage (4), and the outer concrete (5) is formed by pouring through the geotextile bag (7); the heat pump exchange spiral pipe (601) is arranged around the steel reinforcement cage (4), and the heat pump exchange spiral pipe (601) from the ground surface to the geothermal point is buried in the outer concrete (5), and the heat pump exchange straight pipe (602) is laid in the hollow area of the inner steel tube (1), and the heat pump exchange straight pipe (602) from the geothermal point to the ground surface is a straight pipe.

2. The structure of a hollow sandwich steel tube concrete stiffened hybrid energy pile according to claim 1, characterized in that, Both the inner steel tube (1) and the outer steel tube (3) are circular steel tubes.

3. A structure of a hollow sandwich concrete-filled steel tubular stiffened hybrid energy pile according to claim 1, characterized in that, Both the inner steel tube (1) and the outer steel tube (3) are polygonal steel tubes.

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

5. A structure of a hollow sandwich concrete-filled steel tubular stiffened hybrid energy pile according to claim 3 or 4, characterized in that, The polygonal steel tube is a square steel tube, a rectangular steel tube, a regular hexagonal steel tube or a regular octagonal steel tube.

6. A construction method for a stiffened hybrid energy pile structure of concrete-filled steel tubular with hollow sandwich, characterized in that, For constructing a hollow sandwich steel tube concrete stiffened hybrid energy pile structure as described in any one of claims 1-5, the following steps are included: S1: Place the heat pump exchange spiral pipe (601) outside the outer steel tube (3), place the heat pump exchange straight pipe (602) inside the inner steel tube (1), and connect the heat pump exchange spiral pipe (601) and the heat pump exchange straight pipe (602); S2: Pour core concrete (2) between the inner steel tube (1) and the outer steel tube (3) to form a core hollow sandwich steel tube concrete member; S3: Tie a steel reinforcement cage (4) outside the outer steel tube (3), place longitudinal bars (401) with the heat pump exchange spiral pipe (601) as a framework, and tie stirrups (402) to form a steel reinforcement cage (4); S4: Put the steel reinforcement cage (4) and the core hollow sandwich steel tube concrete member into the geotextile bag (7), tie the upper and lower ends of the geotextile bag (7) tightly, and insert a grouting pipe (9) into the bag; S5: Hoist the geotextile bag (7) containing the steel reinforcement cage (4) and the core hollow sandwich steel tube concrete member to the designated position of the drill hole; S6: Inject concrete through the grouting pipe (9) to form a reinforced concrete outer member.

7. The construction method of a hollow sandwich concrete-filled steel tubular stiffened hybrid energy pile structure according to claim 6, characterized in that, In S4, the bottom of the grouting pipe (9) is tightened with a plug (11), and the top of the grouting pipe (9) passes through a collar (10).

8. The construction method of a hollow sandwich steel tube concrete stiffened hybrid energy pile structure according to claim 7, characterized in that, It also includes S7: End the grouting, block the collar (10) with the plug (11), and screw out the grouting pipe (9).

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