A supporting device for coal mining subsidence land, a geothermal utilization system and a utilization method

Abstract

The present invention discloses a support device for coal mining subsidence land, a geothermal utilization system and a utilization method. The bottom of the floating platform is connected to an external frame for righting it in the formation. Since the external frame has a certain frame structure, it can keep the floating platform stable in the formation, and the floating platform can be easily righted through the external frame. The external frame is in the form of an annular structure with a vertically extending axis. The top of the heat extraction platform is connected to an internal frame for righting it in the formation. Since the internal frame has a certain frame structure, it can keep the heat extraction platform stable in the formation, and the heat extraction platform can be easily righted through the internal frame. The internal frame is slidably inserted into the external frame in the vertical direction and extends out of the floating platform, so that the internal frame and the external frame form a frame-type socket structure, further enhancing the stiffness of the two and ensuring the stability of the entire device in the formation.

Description

Technical Field

[0001] The present invention relates to the technical field of energy utilization, and particularly to a supporting device for coal mining subsidence areas, a geothermal utilization system and a utilization method thereof. Background Art

[0002] As is well known, coal mining can cause ground subsidence, and the scope and amplitude of ground subsidence are affected by the gob area formed by coal mining. Taking some mining areas as an example, the total thickness of the main workable coal seams is about 6 - 15 meters. According to the prediction of the ground subsidence amount in the land reclamation plan, after all coal seams are mined, the subsidence amplitude can reach 5 - 10 m after the ground completely subsides. A large amount of water accumulates on the surface after subsidence. Since the stable subsidence period of the ground is relatively long and the ground continues to subside during the stable subsidence period, infrastructure construction and farmland planting cannot be carried out in the water accumulation area, and the accumulated water is a poor conductor of heat, so geothermal clean energy cannot be conveniently utilized, resulting in a large amount of land waste.

[0003] Patent document CN113432322A discloses a comprehensive utilization method and test equipment for surface water, gob areas and geothermal energy in coal mining subsidence areas. First, the geothermal water gathering area is determined, and the roadway layout and surface water channel layout are determined according to the position of the geothermal water gathering area; the geothermal water gathering area includes the junction area between the fault and the geothermal reservoir. A large amount of hot water is easily accumulated in the fault area and the geothermal reservoir area, which is convenient for heat exchange. Then, heat exchange equipment is arranged in the main roadway. The geothermal water is pumped to the heat exchange equipment in the heat exchange station through the geothermal water extraction pipeline, and the heat energy is extracted and then transported to the ground for continuous utilization. Among them, before the mine is sealed at the end of the mine service period, a geothermal well is drilled in the drilling chamber in the main roadway, and the geothermal water extraction pipeline is arranged towards the geothermal water gathering area respectively. To solve the water source problem of geothermal utilization, but it has to wait until the ground completely subsides before the geothermal energy can be developed, is easily affected by the change of the formation structure, and its pipeline setting is complex and the laying process is difficult. Summary of the Invention

[0004] The purpose of the present invention is to provide a supporting device for coal mining subsidence areas, a geothermal utilization system and a utilization method thereof to solve the problems existing in the above-mentioned prior art. By means of an external frame and an internal frame, the floating platform and the heat extraction platform can be conveniently righted respectively. Then, when the ground subsides, the heat extraction platform moves down to the constant temperature layer along with the stratum, and the floating platform floats to the surface layer by relying on the accumulated water, ensuring the effective utilization of geothermal energy.

[0005] To achieve the above object, the present invention provides the following solutions: The present invention provides a support device applied to coal mining subsidence areas, including a floating platform that rises to the surface layer by its own buoyancy and a heat extraction platform that moves down to the constant temperature layer with the ground subsidence. The bottom of the floating platform is connected with an external frame for righting it in the formation. The external frame is in a ring structure with a vertical axis extending. The top of the heat extraction platform is connected with an internal frame for righting it in the formation. The internal frame is slidably inserted in the external frame in the vertical direction and extends out of the floating platform. A number of extendable ropes are provided on both the internal frame and the floating platform, and the external frame and the heat extraction platform are respectively suspended by the ropes.

[0006] Preferably, the external frame includes a bottom support ring and a number of external connecting rods. The external connecting rods are arranged at equal intervals in the circumferential direction between the bottom support ring and the floating platform.

[0007] Preferably, the floating platform includes an annular support cavity filled with foam soft plastic for increasing its buoyancy. The internal frame passes through the inner opening of the support cavity, and the external connecting rods are connected around the inner opening.

[0008] Preferably, the internal frame includes a number of internal connecting rods and a top support ring located above the floating platform. The internal connecting rods are arranged at equal intervals in the circumferential direction between the top support ring and the heat extraction platform. The internal connecting rods pass through the bottom support ring and extend out of the inner opening.

[0009] Preferably, the ropes for suspending the internal frame are connected between the top support ring and the bottom support ring and are arranged at equal intervals in the circumferential direction of the top support ring and the bottom support ring.

[0010] The present invention also provides a geothermal utilization system, including the support device, a circulating pump set arranged on the internal frame, a pipe network structure and a heat exchange pipeline respectively arranged on the heat extraction platform and the floating platform. An extendable connecting pipeline is communicated between the pipe network structure and the heat exchange pipeline. The pipe network structure, the heat exchange pipeline, the connecting pipeline and the circulating pump set are circulated and communicated.

[0011] Preferably, the pipe network structure includes an annular support pipe and a number of pipe network pipes intertwined and connected inside the support pipe. The pipe network pipes are successively communicated by a number of diversion pipes, and a deformable joint pipe is communicated between two adjacent diversion pipes.

[0012] Preferably, both the external connecting rod and the bottom support ring are hollow tubular structures and are connected to the heat exchange pipeline. Both the internal connecting rod and the top support ring are hollow tubular structures and are connected to the pipe network structure. Each of the ropes is tied with a connecting pipeline that extends synchronously with it. The heat exchange pipeline and the pipe network structure, and between the top support ring and the bottom support ring, are correspondingly connected with the connecting pipeline.

[0013] Preferably, the circulating pump group is a heat pump unit and is arranged on the top support ring.

[0014] A geothermal utilization method is also provided, including the following steps:

[0015] Collapse area excavation: Before the ground collapse area collapses, excavate the soil, install the support device, install the heat extraction platform at the bottom of the excavation area, straighten the internal frame and the external frame, keep the floating platform at the top of the excavation area, and bury it.

[0016] Self-collapse of the collapse area: After the ground subsides, the heat extraction platform and the internal frame sink to the constant temperature layer, water accumulates on the ground surface, and under the buoyancy of the accumulated water, and by adjusting the telescopic amount of the rope, the floating platform floats on the ground surface layer.

[0017] Heat exchange: Connect the heat pump unit, the heat exchange pipeline, the pipe network structure, the top support ring, the bottom support ring and the connecting pipeline, and transport the heat of the constant temperature layer to the ground surface layer through the circulating heat exchange medium.

[0018] The present invention has achieved the following technical effects compared with the prior art:

[0019] First, an external frame for righting the floating platform in the formation is connected to the bottom of the floating platform. Since the external frame has a certain frame structure and certain stiffness, it can keep the floating platform stable in the formation. And it is easier to right the floating platform through the external frame, ensuring that the floating platform can move upward stably when water accumulates. The external frame is in a ring structure with a vertically extending axis. An internal frame for righting the heat extraction platform in the formation is connected to the top of the heat extraction platform. Since the internal frame has a certain frame structure and certain stiffness, it can keep the heat extraction platform stable in the formation. And it is easier to right the heat extraction platform through the internal frame, ensuring that the heat extraction platform can move downward stably as the ground subsides. The internal frame is slidably inserted into the external frame in the vertical direction and extends out of the floating platform, so that the internal frame and the external frame form a framed socket structure, further enhancing the stiffness of both and ensuring the stability of the whole device in the formation, avoiding the movement of the whole device caused by ground collapse and water accumulation, and making it unable to stably utilize geothermal energy. A number of extendable ropes are provided on both the internal frame and the floating platform, and the external frame and the heat extraction platform are respectively hung by the ropes. By setting the ropes to hang the internal frame, the external frame, the floating platform and the heat extraction platform from each other, the structural stability of the whole device is further ensured. Moreover, during the process of the floating platform being affected by buoyancy, the ropes on the internal frame contract, raising the external frame and driving the floating platform to move upward, so that the floating platform can move stably to the ground surface.

[0020] Second, the external frame includes a bottom support ring and a number of external connecting rods. The external connecting rods are arranged at equal intervals in the circumferential direction between the bottom support ring and the floating platform. The external frame is formed by the setting of the bottom support ring and the external connecting rods, reducing the restriction on the flow of soil and water accumulation, ensuring that when the floating platform rises with the external frame, the resistance acting on it is reduced. And the uniform arrangement of the external connecting rods makes the external frame more balanced during the movement.

[0021] Third, the floating platform includes an annular support cavity filled with foam soft plastic for increasing its buoyancy. By increasing the foam soft plastic, the floating platform is more easily affected by the buoyancy of water accumulation, reducing the tension of the ropes. The internal frame passes through the inner opening of the support cavity, and the external connecting rods are connected around the inner opening, ensuring that the external connecting rods can be evenly connected to the floating platform, further ensuring the balance effect of the floating platform.

[0022] Fourth, the internal frame includes a number of internal connecting rods and a top support ring located above the floating platform. The internal connecting rods are arranged at equal intervals in the circumferential direction between the top support ring and the heat extraction platform. The internal connecting rods pass through the bottom support ring and extend out of the inner opening. The internal frame is formed by the top support ring and the internal connecting rods, reducing the restriction on the flow of soil and accumulated water, ensuring that when the heat exchange platform moves downward with the internal frame, the resistance acting on it is reduced, and the uniform arrangement of the internal connecting rods makes the internal frame more balanced during the movement process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a state diagram of the distribution of the support device of the present invention in the formation;

[0025] Figure 2 It is a structural diagram of the support device of the present invention;

[0026] Figure 3 It is a schematic diagram of the pipe network structure of the present invention;

[0027] Figure 4 It is a connection diagram of the internal frame of the present invention;

[0028] Figure 5 It is a connection diagram of the external frame of the present invention;

[0029] Among them, 1 - top support ring, 2 - joint pipe, 3 - floating platform, 4 - internal rope, 5 - external rope, 6 - bottom support ring, 7 - internal connecting rod, 8 - heat extraction platform, 9 - external connecting rod, 10 - diversion pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] The object of the present invention is to provide a support device for coal mining subsidence areas, a geothermal utilization system and a utilization method, so as to solve the problems existing in the above-mentioned prior art. By means of an external frame and an internal frame, the floating platform and the heat extraction platform can be conveniently righted respectively. Then, when the ground subsides, the heat extraction platform moves down to the constant temperature layer along with the stratum, and the floating platform floats up to the surface layer by relying on the accumulated water, ensuring the effective utilization of geothermal energy.

[0032] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Please refer to Figures 1 to 5 , this embodiment provides a support device applied to coal mining subsidence areas, including a floating platform that rises to the surface layer by relying on its own buoyancy and a heat extraction platform that moves down to the constant temperature layer as the ground subsides. The bottom of the floating platform is connected with an external frame for righting it in the stratum. Since the external frame has a certain frame structure and certain rigidity, it can keep the floating platform 3 stable in the stratum, and it is relatively easy to right the floating platform 3 through the external frame, ensuring that the floating platform 3 can move up stably when the accumulated water gathers. The external frame is an annular structure with a vertical axis extending. The top of the heat extraction platform 8 is connected with an internal frame for righting it in the stratum. Since the internal frame has a certain frame structure and certain rigidity, it can keep the heat extraction platform 8 stable in the stratum, and it is relatively easy to right the heat extraction platform 8 through the internal frame, ensuring that the heat extraction platform 8 moves down stably as the ground subsides. The internal frame is slidably inserted into the external frame in the vertical direction and extends out of the floating platform 3, so that the internal frame and the external frame form a framed socket structure, further enhancing the rigidity of the two and ensuring the stability of the whole device in the stratum, avoiding the movement of the whole device caused by its movement along with the ground subsidence and the accumulated water, and making it unable to stably utilize geothermal energy. A number of extendable ropes are provided on both the internal frame and the floating platform 3, and the external frame and the heat extraction platform 8 are respectively hung by the ropes to support and balance the gravity of each structure. By setting the ropes to hang the internal frame, the external frame, the floating platform 3 and the heat extraction platform 8 from each other, the structural stability of the whole device is further ensured. Moreover, during the process of the floating platform 3 receiving buoyancy, the ropes on the internal frame contract, raising the external frame and driving the floating platform 3 to move up, so that the floating platform 3 stably moves to the surface. Preferably, the ropes are made of steel cables, etc. The steel cables are deformable soft structures, and the overall strength of the steel cables is ensured by adopting a double-wound structure. Specifically, the steel cables are adjusted and balanced by a small stirring disk. The external frame and the internal frame are made by welding steel structures.

[0034] As a preferred embodiment of the present invention, the internal frame has a conical structure with a gradually decreasing cross-section from bottom to top, and the external frame has a conical structure with a gradually decreasing cross-section from top to bottom. Through the setting of the conical structure, the stiffness of the entire support device is increased, ensuring the balanced setting of the heat extraction platform 8 and the floating platform 3.

[0035] Furthermore, the external frame includes a bottom support ring 6 and a plurality of external connecting rods 9. The external connecting rods 9 are arranged at equal intervals in the circumferential direction between the bottom support ring 6 and the floating platform 3. The external frame is formed by the setting of the bottom support ring 6 and the external connecting rods 9, reducing the restriction on the flow of soil and accumulated water. When the floating platform 3 rises with the external frame, the resistance acting on it is reduced. Moreover, the uniform arrangement of the external connecting rods 9 makes the external frame more balanced during the movement process.

[0036] As a preferred embodiment of the present invention, the floating platform 3 mainly serves as the application end. It includes an annular support cavity. Preferably, the support cavity can be made by connecting an iron skeleton and iron sheets. The support cavity is filled with foam soft plastic for increasing its buoyancy. By increasing the foam soft plastic, the floating platform 3 is more easily affected by the buoyancy of the accumulated water, reducing the tensile force of the rope and the supporting force of the internal frame and the external frame on it. The internal frame passes through the inner opening of the support cavity, and the external connecting rods 9 are connected around the inner opening, ensuring that the external connecting rods 9 can be evenly connected to the floating platform 3, further ensuring the balance effect of the floating platform 3.

[0037] Furthermore, the internal frame includes a plurality of internal connecting rods 7 and a top support ring 1 located above the floating platform 3. The internal connecting rods 7 are arranged at equal intervals in the circumferential direction between the top support ring 1 and the heat extraction platform 8. The internal connecting rods 7 pass through the bottom support ring 6 and extend out of the inner opening. The internal frame is formed by the setting of the top support ring 1 and the internal connecting rods 7, reducing the restriction on the flow of soil and accumulated water. When the heat exchange platform moves downward with the internal frame, the resistance acting on it is reduced. Moreover, the uniform arrangement of the internal connecting rods 7 makes the internal frame more balanced during the movement process.

[0038] Preferably, three groups of external connecting rods 9 and internal connecting rods 7 are provided. Using the principle of the stability of the triangular structure, the stability of the entire support device can be fully ensured to the greatest extent of simplification.

[0039] Further, the ropes for hanging the inner frame are connected between the top support ring 1 and the bottom support ring 6, and are arranged at equal intervals circumferentially along the top support ring 1 and the bottom support ring 6, facilitating the arrangement of the ropes through the top support ring 1 and the bottom support ring 6. The balance of the entire support device is adjusted through the top support ring 1 and the bottom support ring 6. Preferably, gear structures are provided at the connection points of the ropes on both the top support ring 1 and the bottom support ring 6 to adjust the length of the ropes. The ropes connected between the top support ring 1 and the bottom support ring 6 are inner ropes 4, and the ropes connected between the floating platform 3 and the heat exchange platform are outer ropes 5, which surround the inner ropes 4.

[0040] Further, a geothermal utilization system is also provided, which includes a support device, a circulating pump set arranged on the inner frame, a pipe network structure and a heat exchange pipeline respectively arranged on the heat extraction platform 8 and the floating platform 3. An extendable connecting pipeline is communicated between the pipe network structure and the heat exchange pipeline, and the pipe network structure, the heat exchange pipeline, the connecting pipeline and the circulating pump set are circulated and communicated. Preferably, the pipe network structure, the heat exchange pipeline and the connecting pipeline can all be made of bundled soft plastic pipes or PE material pipes along the heat extraction platform 8, the floating platform 3, the inner frame and the outer frame. Their connection strength mainly depends on each frame structure and steel cables. Through the connection of each pump set and pipeline, the heat exchange medium in the heat exchange pipeline at the floating platform 3 is transported to the pipe network structure, exchanges heat with the constant temperature layer, and then circulates back to realize the utilization of geothermal energy, so as to be able to re-plan the surface and underground space resources in the water accumulation area, reuse the abandoned area, turn waste into treasure, and improve the application value.

[0041] As a preferred embodiment of the present invention, the pipe network structure serves as the heat extraction end, which includes an annular support pipe and several pipe network pipes intertwined and connected inside the support pipe. The pipe network pipes are sequentially communicated by several diversion pipes 10, and a deformable joint pipe 2 is communicated between adjacent two diversion pipes 10. Then, even during the process of ground subsidence, due to the deformability of the joint pipe 2, it will not affect the connection of the pipe network structure. Preferably, the diversion pipes 10 and the support pipe are made of steel pipelines, having certain strength and corrosion resistance, and the joint pipe 2 adopts anti-deformation joints, etc. Then, after the excavation of the soil, the support pipe and the pipe network pipes are laid to form the pipe network structure, and then the inner frame and the outer frame and other support facilities are set up. Then, after the installation of the support facilities is completed, the floating platform 3 is built.

[0042] Furthermore, both the external connecting rod 9 and the bottom support ring 6 are hollow tubular structures and are connected to the heat exchange pipeline. The internal connecting rod 7 and the top support ring 1 are both hollow tubular structures and are connected to the pipe network structure. Each rope is tied with a connecting pipeline that extends synchronously with it. Connecting pipelines are correspondingly connected between the heat exchange pipeline and the pipe network structure, and between the top support ring 1 and the bottom support ring 6, thereby reducing the setting of the connecting pipelines and reducing the impact of ground subsidence on the connecting pipelines.

[0043] Preferably, three ropes connected to the top support ring 1 are preferably provided and evenly arranged in the circumferential direction. Its main functions are: balancing and adjusting the floating platform 3, the external connecting rod 9 and the top support ring 1, so that the floating platform 3 is horizontal, and tying the connecting pipeline along the ropes; three ropes connected to the bottom support ring 6 are preferably provided and evenly arranged in the circumferential direction. Its main functions are: balancing and adjusting the heat extraction platform 8, the internal connecting rod 7 and the bottom support ring 6, so that the heat extraction platform 8 is in a horizontal position, and the connecting pipeline is also tied to the above ropes accordingly to complete the transmission of the heat exchange medium of the entire device.

[0044] As a preferred embodiment of the present invention, the circulating pump group is a heat pump unit and is arranged on the top support ring 1, so that the circulating pump group can extend out of the ground surface, which is convenient for the maintenance of the circulating pump group and the like.

[0045] A geothermal utilization method is also provided, including the following steps:

[0046] Excavation in the subsidence area: Before the ground subsidence area has subsided, excavate the soil, install the support device, install the heat extraction platform 8 at the bottom of the excavation area, straighten the internal frame and the external frame, keep the floating platform 3 at the top of the excavation area, and bury it; Preferably, according to the national shallow geothermal energy survey and evaluation results, the constant temperature layer in most parts of the country is located at a depth of 15-30m underground, and the temperature at this depth is constantly about 15-19℃ throughout the year and does not change with the seasons; Therefore, when excavating the soil, after digging about 5-10m deep, place the support device.

[0047] Self-subsidence in the subsidence area: After the ground subsides, the heat extraction platform 8 and the internal frame sink to the constant temperature layer. Preferably, due to the ground subsidence and the coverage of the water accumulation area, the heat extraction platform 8 sinks 20m below the groundwater level. This depth is already in the constant temperature layer throughout the year, and water accumulates on the ground surface. Under the buoyancy of the water accumulation, and by adjusting the telescopic amount of the ropes, the floating platform 3 floats on the surface layer; Among them, according to the general subsidence prediction in the coal mining area, the depth of the water accumulation area is 5-10m, and the buoyancy generated by the water accumulation will greatly reduce the support of the support device on the floating platform 3. At this time, the main function of the support device is to adjust the balance between the floating platform 3 and the heat exchange platform to make it horizontal and ensure the use effect.

[0048] Heat exchange: Connect the heat pump unit, heat exchange pipeline, pipe network structure, top support ring 1, bottom support ring 6 and connecting pipeline. Circulate the ground and underground temperatures through the heat pump unit, so that the floating platform 3 is in a constant temperature state all year round. That is, the heat of the constant temperature layer is transported to the surface layer by circulating the heat exchange medium. A characteristic greenhouse planting area can be built on it, and a characteristic greenhouse fish pond breeding area can be built under it. The three-dimensional application has higher economic benefits and greater value for land reclamation and mine greening. Among them, water or the like can be used as the circulating heat exchange medium to reduce the use cost.

[0049] Any adaptive changes made according to actual needs are within the protection scope of the present invention.

[0050] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0051] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A support device applied to coal mining subsidence areas, characterized in that, It includes a floating platform that rises to the surface layer by relying on its own buoyancy, and a heat extraction platform that moves down to the constant temperature layer as the ground collapses. The bottom of the floating platform is connected to an external frame for righting it in the formation. The external frame is an annular structure with a vertically extending axis. The top of the heat extraction platform is connected to an internal frame for righting it in the formation. The internal frame is slidably inserted into the external frame in the vertical direction and extends out of the floating platform. A number of extendable ropes are provided on both the internal frame and the floating platform, and the external frame and the heat extraction platform are respectively suspended by the ropes. The external frame includes a bottom support ring and a number of external connecting rods. The external connecting rods are arranged at equal intervals in the circumferential direction between the bottom support ring and the floating platform. The internal frame includes a number of internal connecting rods and a top support ring located above the floating platform. The internal connecting rods are arranged at equal intervals in the circumferential direction between the top support ring and the heat extraction platform. The internal connecting rods pass through the bottom support ring and extend out of the inner opening. The ropes for suspending the internal frame are connected between the top support ring and the bottom support ring and are arranged at equal intervals in the circumferential direction of the top support ring and the bottom support ring.

2. The support device applied to the coal mining subsidence area according to claim 1, wherein The floating platform includes an annular support cavity filled with foam soft plastic for increasing its buoyancy. The internal frame passes through the inner opening of the support cavity, and the external connecting rods are connected around the inner opening.

3. A geothermal utilization system for a support device applied to coal mining subsidence areas as described in claim 2, characterized in that, It includes the support device, a circulating pump group arranged on the internal frame, a pipe network structure and a heat exchange pipeline respectively arranged on the heat extraction platform and the floating platform. An extendable connecting pipeline is connected between the pipe network structure and the heat exchange pipeline. The pipe network structure, the heat exchange pipeline, the connecting pipeline and the circulating pump group are connected in a cycle.

4. The geothermal utilization system according to claim 3, characterized in that, The pipe network structure includes an annular support pipe and a number of pipe network pipes intertwined and connected inside the support pipe. The pipe network pipes are successively connected by a number of diversion pipes, and a deformable joint pipe is connected between adjacent two diversion pipes.

5. The geothermal utilization system according to claim 4, characterized in that, Both the external connecting rod and the bottom support ring are hollow tubular structures and are connected to the heat exchange pipeline. Both the internal connecting rod and the top support ring are hollow tubular structures and are connected to the pipe network structure. Each rope is tied with a connecting pipeline that extends synchronously with it. Connecting pipelines are correspondingly connected between the heat exchange pipeline and the pipe network structure, and between the top support ring and the bottom support ring.

6. The geothermal utilization system according to claim 5, characterized in that The circulating pump group is a heat pump unit and is arranged on the top support ring.

7. A geothermal utilization method using the geothermal utilization system according to any one of claims 3 to 6, characterized in that, It includes the following steps: Excavation in the subsidence area: Before the ground subsidence area collapses, excavate the soil, install the support device, install the heat extraction platform at the bottom of the excavation area, right the internal frame and the external frame, keep the floating platform at the top of the excavation area, and bury it. Self-collapse of the subsidence area: After the ground subsides, the heat extraction platform and the internal frame sink to the constant temperature layer, water accumulates on the surface, and the floating platform floats on the surface layer under the buoyancy of the accumulated water and by adjusting the telescopic amount of the ropes. Heat exchange: Connect the heat pump unit, the heat exchange pipeline, the pipe network structure, the top support ring, the bottom support ring and the connecting pipeline, and transfer the heat of the constant temperature layer to the surface layer through the circulating heat exchange medium.

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