Underground lining gas storage large-scale physical model test platform and test method thereof

Abstract

The invention discloses an underground lining gas storage large-scale physical model test platform and a test method thereof, the platform is composed of an internal pressure loading module, a reservoir surrounding rock simulation module and a data monitoring module, the internal pressure loading module adopts an oil / water pressure conversion device and PLC closed-loop control to realize full-process automatic circulation of loading-pressure stabilization-pressure relief-pressure stabilization; the surrounding rock simulation module comprises an adjustable model box, a confining pressure loading device and a cooperative pressure-bearing sealing structure of an opposite-pulling type flange and a flexible sealing element, and segmented pouring can be achieved to simulate the strength difference of a complex stratum. The matching test method comprises the steps of similar material proportioning and parameter calibration, precast slab pouring and sensor arrangement, sealing connection, confining pressure initialization, internal pressure cyclic loading and linkage acquisition and the like. The device is suitable for the physical simulation test of the multi-working-condition underground lining gas storage, the high-pressure multi-cycle complex working condition of the chamber can be stably reproduced, and reliable test support is provided for stability evaluation and structural design of the underground lining gas storage.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to a large physical model test platform for underground lined gas storage and its test method. Background Technology

[0002] With the rapid increase in the installed capacity of renewable energy, the demand for large-capacity, long-life, and adjustable energy storage technologies in the power system continues to grow. Compressed air energy storage systems, which compress air during off-peak hours and store it in underground space, and release the compressed air during peak hours to drive generators, are an energy storage approach that combines large-scale operation with environmental friendliness.

[0003] Among various types of usable underground spaces, underground lined gas storage facilities are considered an important future development direction for CAES (Conditional Earth Storage and Engineering) projects due to their mature construction technology and wide adaptability. However, under high-pressure, multi-cycle operation conditions, the surrounding rock and lining structure of lined gas storage facilities are subjected to alternating loads and complex geological and environmental disturbances over a long period of time, which can easily lead to cumulative damage and degradation of sealing performance, directly affecting the long-term stability and airtightness of the gas storage facility. In particular, for long-span gas storage chambers commonly seen in engineering projects, the axial extension distance of the chamber is long, and the stratigraphic combination is complex. The strength and stiffness of the surrounding rock often exhibit significant heterogeneity along the spatial distribution (such as weak interlayers, lithological abrupt change zones, joint and fissure enrichment areas, etc.), resulting in significantly uneven deformation and stress response around the chamber, localized stress concentration in the lining and accelerated damage evolution. Against this backdrop, how to reproduce the deformation and failure process under the coupled action of "heterogeneous surrounding rock - lining constraint - cyclic internal pressure" under controllable conditions, and obtain highly reliable data that can be used for mechanism analysis and structural design, has become an important technical problem restricting the safety evaluation and optimization design of underground lined gas storage facilities.

[0004] Existing research mainly relies on theoretical analysis, numerical simulation, and a small number of field tests and small-scale physical model tests. Theoretical and numerical methods are inevitably constrained by the idealization of constitutive models, parameter uncertainties, and boundary simplifications; field tests are time-consuming, costly, and have limited controllability of operating conditions; small-scale model tests are easily limited by size effects and loading capacity, making it difficult to realistically reproduce the three-dimensional stress-strain field under high pressure and multi-cycle conditions, and it is difficult to flexibly simulate the heterogeneous zoning and complex stratigraphic structure of the surrounding rock, and it is difficult to reflect the engineering reality of the spatial inconsistency of the strength of the surrounding rock in long-span chambers.

[0005] Therefore, it is necessary to develop a physical model test platform with large geometric scale, high loading capacity, multi-source monitoring and automated control functions, and to provide a set of test methods that can carry out systematic tests under different surrounding rock strength levels, different internal pressure operating regimes and different number of cycles, so as to shorten the scale gap between theoretical-numerical research and engineering practice. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a large-scale physical model test platform and test method for underground lined gas storage facilities.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A large-scale physical model test platform for an underground lined gas storage facility includes a test platform system, which comprises an internal pressure loading module, a storage facility surrounding rock simulation module, a data monitoring module, and a data acquisition module. The internal pressure loading module includes an oil / water pressure conversion device, a pressure control device, and a pressure monitoring device; The oil / water pressure conversion device includes a water pump, an oil pump, an oil / water pressure conversion device, a hydraulic wire hose, a water tank, and an oil tank; The chamber surrounding rock simulation module includes a chamber sealing device, a confining pressure loading device, and an adjustable model box; The data monitoring module includes a distributed optical fiber acquisition device, a static stress-strain acquisition device, and an acoustic emission monitoring device; the distributed optical fiber acquisition device and the static stress-strain acquisition device monitor the data through a strain monitoring prefabricated plate. The data acquisition module includes a data demodulation device and a computer.

[0008] In one possible design, the water pump supplies water pressure to the oil / water pressure conversion device, and under the action of oil pressure, squeezes the water inside the oil / water pressure conversion device to generate corresponding water pressure, which is then connected to the chamber sealing device via the hydraulic wire hose, thereby realizing the loading of water pressure inside the chamber sealing device.

[0009] In one possible design, the pressure control device controls the oil / water pressure conversion device by outputting signals from the PLC host in the control box, thereby realizing automated program control of the entire process of "loading-stabilizing-unloading-stabilizing".

[0010] In one possible design, the pressure monitoring device is a pressure transmitter arranged between the oil / water pressure conversion device and the oil pump pipeline to monitor water pressure and oil pressure.

[0011] In one possible design, the chamber sealing device includes a first flange, a second flange, EPDM rubber, and four galvanized steel bars.

[0012] In one possible design, a drain outlet is provided on one side of the first flange, and a water inlet and an air vent are provided on one side of the second flange, along with a safety valve.

[0013] In one possible design, the chamber sealing device includes a sealing pipe made of EPDM rubber inside the chamber. The end of the rubber sealing pipe is specially turned outward, and the first flange and the second flange are mechanically reinforced by four galvanized steel bars. The sealing ring is squeezed to achieve a reliable seal that simulates the chamber.

[0014] In one possible design, the strain monitoring precast slab is constructed using a two-stage casting process: After the first pour is completed and cured to the design strength, optical fibers and strain gauges are attached to the concrete surface. Epoxy resin was then used to wrap and protect the optical fiber and strain gauge to prevent damage during subsequent construction. After the epoxy resin has cured, a second concrete pour is made to completely cover the sensor and form a complete strain monitoring precast panel.

[0015] A method for testing a large-scale physical model of an underground lined gas storage facility, applied to the aforementioned large-scale physical model testing platform, includes the following steps: S1: Based on the simulation requirements of the mechanical properties of surrounding rock in the actual physical model test, it is necessary to first determine the similar material ratio that can accurately reflect the mechanical behavior of the real rock mass. On this basis, a series of mechanical property tests such as uniaxial compression test and Brazilian splitting test should be carried out simultaneously to systematically obtain key parameters such as compressive strength, tensile strength, elastic modulus, and Poisson's ratio of the material, so as to comprehensively evaluate the rationality of the ratio scheme and provide a reliable material mechanics basis for subsequent similar model tests. S2: Fabricate strain monitoring precast slabs and arrange optical fibers and strain sensors using a two-stage pouring process: After the first pour is completed and cured to the design strength, optical fibers and strain gauges are pasted onto the concrete surface. Then, epoxy resin is used to wrap and protect the optical fibers and strain gauges to prevent damage during subsequent construction. After the epoxy resin has cured, a second concrete pour is carried out to completely cover the sensors and form a complete strain monitoring precast slab. The acoustic emission sensors of the acoustic emission monitoring device are arranged on the surface of the surrounding rock of the chamber. The similar materials and proportions used in the precast slab are consistent with those of the surrounding rock. Curing is carried out after pouring. S3: The strain monitoring precast slab is pre-installed in the designated position inside the adjustable model box. Then, the template system is erected, and a layered and segmented pouring process is adopted to simulate the material distribution and structural characteristics under actual complex geological conditions. After the pouring is completed, the formwork is removed at the specified time, and the formed concrete test block is continuously cured under standard conditions to ensure that its strength development meets the test design requirements. S4: Securely place the large rubber sealing pipe into the chamber and position it so that its outer wall is fully in contact with the rock wall of the chamber. Then, lift the heavy flange and align it precisely, and install it at the openings at both ends of the chamber. Finally, use four high-strength galvanized steel bars to pull through the first flange and the second flange, and apply pre-tightening force through hydraulic tensioning equipment to achieve uniform and reliable anchoring and sealing. S5: Connect the pressurization system to the flange inlet and integrate three types of monitoring equipment: strain, fiber optic, and acoustic emission, to build a complete real-time monitoring network. Then, conduct systematic linkage debugging. During the test, initialize the confining pressure loading device to simulate the target stress environment. Then, set the pressure threshold, loading rate, and number of cycles in the loading control unit, and start all monitoring equipment to collect data in real time and synchronously. Beneficial effects

[0016] The internal pressure loading module used in the test system of this invention mainly consists of a hydraulic oil tank, an oil pump, a proportional relief valve, a return oil filter, an oil / water pressure conversion device, a water tank, a water pump, an inlet solenoid valve, an electromagnetic proportional valve, a stop valve, a pressure relief solenoid valve, and a control box. The oil pump provides oil pressure to the oil / water pressure conversion device through hydraulic pipelines, and the water pump provides water pressure to the oil / water pressure conversion device. Under the action of oil pressure, the water inside the conversion device is squeezed to generate a corresponding water pressure, which is then connected to the chamber through a hydraulic steel wire hose, thereby realizing the loading and regulation of the water pressure inside the chamber. The PLC host in the control box outputs signals to the electromagnetic proportional valve, the inlet solenoid valve, the proportional relief valve, etc., to precisely regulate the pressure, loading rate, and number of cycles, realizing the automated program control of the entire process of "loading-stabilizing-releasing-stabilizing". The control box and oil pump are assembled into an integrated vertical bracket, and a cooler is provided to cool the motor. All components are connected by high-strength hydraulic steel wire hoses. The oil / water pressure conversion device is made of stainless steel. A pressure transmitter is installed between the oil / water pressure conversion device and the oil pump pipeline to monitor water pressure and oil pressure. The cavern surrounding rock simulation module of this invention mainly consists of a confining pressure device, a cavern sealing device, and an adjustable model box. The confining pressure loading device simulates the ground stress around the cavern by applying a preset directional stress. The cavern sealing device is a pressure-bearing and sealing structure consisting of a pull-type flange and a flexible sealing element. Inside the cavern, a sealing pipe made of EPDM rubber is installed, the size of which is precisely matched to the diameter and length of the simulated cavern. The end of the rubber sealing pipe is specially outward-facing and mechanically reinforced with four galvanized steel bars, firmly fixing it to the end of the sample. Reliable sealing of the simulated cavern is achieved by compressing the sealing ring. Water inlet, water outlet, and air vent valve are provided on the flanges at both ends, along with a safety valve. The adjustable model box is integrally welded from Q345B high-quality structural steel with a steel plate thickness of 15mm, providing reliable mechanical support for the experiment. At the same time, steel grating is welded inside the box to enhance structural stability, ensuring that the adjustable model box has sufficient overall rigidity and deformation resistance during the experiment. The adjustable model box has detachable covers at both ends, which can be used to adjust the size of the casting model according to the test requirements. In addition, it can realize segmented casting (casting cement of different strengths to simulate complex geological conditions), which facilitates the installation of the chamber simulation system and the flexible adjustment of test conditions. A circular chamber with a diameter of 0.4m is reserved on the cover plates at both ends. The data monitoring module used in the test system of this invention mainly consists of a distributed optical fiber acquisition device, a static stress-strain acquisition device, and an acoustic emission monitoring device. The distributed optical fiber acquisition device and the static stress-strain acquisition device monitor the data through a strain monitoring precast plate. The strain monitoring precast plate adopts a two-stage casting process: after the first casting is completed and cured to the design strength, optical fibers and strain gauges are pasted on the concrete surface. Then, epoxy resin is used to wrap and protect the optical fibers and strain gauges to prevent them from being damaged in subsequent construction. After the epoxy resin has cured, a second concrete casting is carried out to completely cover the sensors and form a complete strain monitoring precast plate. The acoustic emission sensors of the acoustic emission monitoring device are arranged on the surface of the surrounding rock of the chamber. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the test system for a large physical model test platform for an underground lined gas storage facility proposed in this invention. Figure 2 This is a schematic diagram of the segmented casting and strain monitoring precast slab installation structure of a large physical model test platform for an underground lined gas storage facility proposed in this invention. Figure 3 This is a schematic diagram of a pressure-bearing and sealing structure of a pull-type flange and flexible sealing element for a large physical model test platform of an underground lined gas storage facility proposed in this invention. Figure 4This is a schematic diagram of the internal pressure loading principle structure of a large physical model test platform for an underground lined gas storage facility proposed in this invention. Figure 5 This is a schematic diagram of the oil / water pressure conversion device of a large physical model test platform for an underground lined gas storage facility proposed in this invention. Figure 6 This is a schematic diagram of the test process structure of a large physical model test platform for an underground lined gas storage facility proposed in this invention.

[0018] In the diagram: 1. Internal pressure loading device; 2. Pressure transmitter; 3. Oil / water pressure conversion device; 4. Water tank; 5. Water pump; 6. Computer; 7. Data demodulation device; 8. Confining pressure device; 9. Hydraulic steel wire hose; 10. Adjustable model box; 11. First flange; 12. Confining pressure device control cabinet; 13. Second flange; 14. Strain monitoring precast slab; 15. Strain monitoring precast slab monitoring point; 16. Drain outlet; 17. Sealing ring; 18. Sealing gasket; 20. Surrounding rock; 21. Galvanized steel bar; 22. Water inlet; 23. Exhaust valve; 24. Hydraulic plug; 25. High-pressure oil inlet; 26. Oil chamber; 27. Hydraulic cylinder; 28. Piston sealing assembly; 29. ​​Hydraulic cylinder; 30. Piston rod; 31. Water chamber; 32. Hydraulic plug; 33. Low-pressure drain outlet. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] In one embodiment: Refer to Figures 1-6 An experimental platform includes: an internal pressure loading module: the module includes an internal pressure loading device 1, a pressure transmitter 2, an oil / water pressure conversion device 3, a water tank 4, a water pump 5, and a hydraulic wire rope 9; the output end of the internal pressure loading device 1 is connected to the pressure transmitter 2, and the pressure transmitter 2 is connected to the oil pressure side interface of the oil / water pressure conversion device 3 through a pipeline; the bottom of the water tank 4 is equipped with a water pump 5, and the water outlet end of the water pump 5 is connected to the water pressure side interface of the oil / water pressure conversion device 3 through a pipeline to supply water medium to the oil / water pressure conversion device 3; the pressure output end of the oil / water pressure conversion device 3 is connected to the chamber interface inside the adjustable model box 10 through the hydraulic wire rope 9, for delivering pressure medium into the chamber model to achieve the application of target internal pressure.

[0021] Confining pressure loading device: It consists of confining pressure device 8 and confining pressure device control cabinet 12. The confining pressure device 8 is connected to the outer peripheral interface of the adjustable model box 10 through an adapter pipeline. The confining pressure device control cabinet 12 is electrically connected to the confining pressure device 8 and is used to regulate the magnitude and stability of the confining pressure applied by the confining pressure device 8 to the adjustable model box 10.

[0022] The adjustable model box 10 is the core carrier of the test. The front of the adjustable model box 10 is sealed and assembled through the first flange 11. Its internal chamber interface is connected to the hydraulic steel wire hose 9 to receive the internal pressure medium, and its external interface is connected to the pipeline of the confining pressure device 8 to receive the confining pressure.

[0023] Data acquisition module: includes data demodulation device 7 and computer 6; the signal input end of data demodulation device 7 is connected to the sensing element and pressure transmitter 2 on the adjustable model box 10 by cables, and the signal output end is electrically connected to computer 6, used to collect pressure and model mechanical response data during loading process, and transmit them to computer 6 for storage and analysis.

[0024] The second flange 13 is mounted on the back of the adjustable model box 10 and is sealed to the end side of the model box by fasteners. On the one hand, it realizes the sealing of the model box cavity, and on the other hand, it provides positioning and fixing support for the axial end of the chamber model, ensuring the positional stability of the chamber model during the loading test.

[0025] The strain monitoring precast plate 14 is arranged at intervals along the axial direction of the chamber model inside the model box. Its plate surface is correspondingly attached to the outer peripheral wall of the chamber model. The plate body integrates a strain sensing carrier structure to carry the strain monitoring element and is the carrier for collecting the strain signal of the surrounding rock of the chamber.

[0026] The strain monitoring points 15 are arranged on the surface of the strain monitoring precast plate 14, specifically corresponding to different circumferential areas of the chamber model. This is used to accurately arrange strain sensors, realize fixed-point monitoring of strain response at multiple locations in the circumferential and radial directions of the chamber surrounding rock, and ensure the spatial coverage of test data.

[0027] The core test carrier is a rectangular surrounding rock 20, with multiple galvanized steel bars 21 inserted horizontally inside. The galvanized steel bars 21 and the surrounding rock 20 are interlocked and cast together to enhance the overall mechanical stability of the surrounding rock 20 and prevent non-targeted cracking of the surrounding rock 20 during the test loading process.

[0028] The axial end of the surrounding rock 20 is sealed and assembled through the first flange 11 and the second flange 13: a sealing gasket 18 and a sealing ring 17 are sequentially arranged between the first flange 11, the second flange 13 and the end face of the surrounding rock 20; the sealing gasket 18 is fitted to the end face of the surrounding rock 20, and the sealing ring 17 is embedded in the corresponding sealing groove of the first flange 11 and the second flange 13. The two work together to achieve a sealed connection between the first flange 11, the second flange 13 and the surrounding rock 20, ensuring the pressure-bearing and sealing performance of the cavity.

[0029] The sides of the flanges are respectively equipped with media interfaces: a drain port 16 is opened on one side of the first flange, and a water inlet 22 is opened on one side of the second flange 13. Both the drain port 16 and the water inlet 22 are connected to the internal cavity enclosed by the surrounding rock 20, and are used for the discharge and injection of the test medium, respectively. At the same time, an exhaust valve 23 is connected to the top of the second flange 13. The exhaust valve 23 is connected to the internal cavity and is used to discharge the air inside the cavity during the medium injection process to ensure sufficient medium filling.

[0030] All components work together to form a sealed pressure-bearing cavity. The circulation and regulation of the test medium are achieved through the water inlet 22 and the water outlet 16. The pressure stability of the cavity is ensured by the sealing components. The galvanized steel bars 21 enhance the structural reliability of the surrounding rock model and meet the working condition simulation requirements of the storage surrounding rock pressure loading test.

[0031] The oil tank serves as the medium storage unit. An air filter is installed on the top of the oil tank (to ensure the balance of air pressure inside and outside the oil tank), and a level gauge (to monitor the oil level) and a temperature sensor (to monitor the oil temperature) are installed inside. The oil outlet of the oil tank is connected in sequence to the oil filter and the oil pump motor. The oil pump motor provides power to the oil circuit and drives the oil into the subsequent circuit. The main oil circuit is connected to a proportional relief valve, which is used to regulate the working pressure of the oil circuit system. Its return end is connected to the oil tank through the return oil pipe to realize the oil circulation.

[0032] Water tank 4 serves as the water medium storage unit. The outlet of water tank 4 is connected to a water pump motor via a water filter. The water pump motor drives the water medium to pass through the inlet solenoid valve and the solenoid proportional valve in sequence. The solenoid proportional valve is used to adjust the output pressure of the water circuit. Its outlet is connected to the test chamber (the carrier for applying the test load). The return water end of the test chamber is connected to the return water pipe via a return water filter and a shut-off valve, and finally flows back to water tank 4, forming a water medium circulation loop.

[0033] The oil / water pressure conversion device 3 connects the oil pressure side to the main oil circuit and the water pressure side to the main water circuit, converting the pressure output from the oil circuit into the pressure required for water circuit loading. The control and protection components include: a pressure sensor (to monitor the pressure of the test chamber in real time), a pressure gauge switch (to control the on / off state of the pressure monitoring element), a pressure relief solenoid valve and a needle valve (connected in parallel to the test chamber circuit for rapid pressure relief in case of overpressure).

[0034] The oil circuit power subsystem provides a pressure source, which is converted into the target water pressure by the oil / water pressure conversion device 3. The water circuit loading subsystem then delivers the pressure medium to the test chamber. The control and protection components monitor parameters such as pressure and temperature in real time to ensure the accuracy and safety of the loading process and meet the working conditions of the internal pressure cyclic loading test of the surrounding rock of the reservoir.

[0035] This application can be used in the field of compressed air energy storage, or in other fields applicable to this application.

[0036] In another embodiment: a large-scale physical model test platform for an underground lined gas storage facility, applied to the field of compressed air energy storage. The structure of this embodiment is basically the same as the aforementioned embodiments, except that: In another aspect of this embodiment, the oil / water pressure conversion device 3 includes an oil pressure plug 24, a high-pressure oil inlet 25, an oil chamber 26, an oil pressure cylinder 27, a piston sealing assembly 28, a water pressure cylinder 29, a piston rod 30, a water chamber 31, a water pressure plug 32, and a low-pressure drain outlet 33. The interior of the hydraulic cylinder body 27 forms an oil chamber 26. A hydraulic plug 24 is detachably mounted on the left end of the hydraulic cylinder body 27. A high-pressure oil inlet 25 is provided on one side of the hydraulic cylinder body 27 corresponding to the high-pressure oil inlet 25, which is connected to the oil chamber 26 for inputting high-pressure oil into the oil chamber 26. The piston rod 30 is coaxially inserted into the interior of the hydraulic cylinder body 27 and the subsequent water cylinder body 29. A piston sealing assembly 28 is fitted on the outer peripheral wall of the piston rod 30 at the separation position between the oil chamber 26 and the water chamber 31. The outer periphery of the piston sealing assembly 28 is sealed to the inner wall of the hydraulic cylinder body 27 and the water cylinder body 29 to achieve media isolation between the oil chamber 26 and the water chamber 31. The right end of the hydraulic cylinder 29 is fixedly connected to the right end of the oil cylinder 27, and the interior of the hydraulic cylinder 29 encloses a water chamber 31. A hydraulic plug 32 is detachably mounted on the right end of the hydraulic cylinder 29, and a low-pressure drain port 33 is provided on the corresponding side wall of the hydraulic cylinder 29. The low-pressure drain port 33 is connected to the water chamber 31 and is used to discharge the converted low-pressure water. The piston rod 30 can reciprocate linearly along the axial direction of the oil cylinder 27 and the hydraulic cylinder 29 to complete the pressure-medium conversion action between the oil chamber 26 and the water chamber 31.

[0037] The complete experimental technology chain, from material preparation and model fabrication to pressure loading, is sequentially linked to achieve the simulation of the mechanical response of the reservoir surrounding rock under working conditions. Based on the actual geological conditions of the CAES project, we first carried out similar material proportioning and configured test materials that matched the mechanical properties of the surrounding rock on site. Then, we verified the strength, deformation and other parameters of the materials through mechanical property testing to ensure that the materials were suitable for the test requirements and to provide a foundation for subsequent model preparation.

[0038] The model box was assembled to build the test carrier frame. Based on the assembled model box, precast slabs were installed and precast slabs were poured for monitoring (the material state during the pouring process was monitored simultaneously). After pouring, fiber optic strain gauges were deployed (pre-set sensing units for subsequent mechanical response acquisition). Then, segmented test blocks were poured. After demolding and curing, the formed surrounding rock model components were obtained. For the cured model components, a sealing structure was first installed to ensure the pressure-bearing sealing of the test. Then, the pressure pipeline connection was completed to build the medium transmission loop between the model and the pressure loading system, preparing for subsequent pressure loading.

[0039] First, based on the loading rate and confining pressure parameters, confining pressure is applied to the model to simulate the external geostress environment of the reservoir surrounding rock. After the confining pressure stabilizes, internal pressure is applied in combination with the number of cycles, loading rate, and upper limit pressure parameters to reproduce the cyclic pressure conditions of the CAES engineering reservoir's gas filling and releasing process.

[0040] Ultimately, it can achieve full-chain test control of "material-model-loading" to ensure the consistency between test conditions and actual CAES engineering.

[0041] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0042] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A large-scale physical model test platform for an underground lined gas storage facility, characterized in that, It includes a test platform system, which comprises an internal pressure loading module, a cavern surrounding rock simulation module, a data monitoring module, and a data acquisition module; The internal pressure loading module includes an oil / water pressure conversion device, a pressure control device, and a pressure monitoring device; The oil / water pressure conversion device includes a water pump (5), an oil pump, an oil / water pressure conversion device (3), a hydraulic wire hose (9), a water tank (4), and an oil tank; The cavern surrounding rock simulation module includes a cavern sealing device, a confining pressure loading device, and an adjustable model box (10). The data monitoring module includes a distributed optical fiber acquisition device, a static stress and strain acquisition device, and an acoustic emission monitoring device; the distributed optical fiber acquisition device and the static stress and strain acquisition device monitor the data through a strain monitoring prefabricated plate (14); The data acquisition module includes a data demodulation device (7) and a computer (6).

2. The large-scale physical model test platform for an underground lined gas storage facility according to claim 1, characterized in that, The water pump (5) provides water pressure to the oil / water pressure conversion device (3), and under the action of oil pressure, it squeezes the water inside the oil / water pressure conversion device (3) to generate corresponding water pressure, and connects to the chamber sealing device through the hydraulic steel wire hose (9), thereby realizing the loading of water pressure inside the chamber sealing device.

3. The large-scale physical model test platform for an underground lined gas storage facility according to claim 2, characterized in that, The pressure control device controls the oil / water pressure conversion device (3) by outputting signals from the PLC host in the control box, thereby realizing the automated program control of the entire process of "loading-stabilizing-unloading-stabilizing".

4. The large-scale physical model test platform for an underground lined gas storage facility according to claim 3, characterized in that, The pressure monitoring device is a pressure transmitter (2) arranged between the oil / water pressure conversion device (3) and the oil pump pipeline, used to monitor water pressure and oil pressure.

5. The large-scale physical model test platform for an underground lined gas storage facility according to claim 4, characterized in that, The chamber sealing device includes a first flange (11), a second flange (13), EPDM rubber, and four galvanized steel bars (21).

6. The large-scale physical model test platform for an underground lined gas storage facility according to claim 5, characterized in that, A drain outlet (16) is provided on one side of the first flange (11), and a water inlet (22) and an air vent (23) are provided on one side of the second flange (13), and a safety valve is also provided.

7. The large-scale physical model test platform for an underground lined gas storage facility according to claim 6, characterized in that, The chamber sealing device has a section of sealing pipe made of EPDM rubber inside the chamber. The end of the sealing pipe is turned outward and the first flange (11) and the second flange (13) are mechanically reinforced by four galvanized steel bars (21). The simulated chamber is reliably sealed by squeezing the sealing ring (17).

8. The large-scale physical model test platform for an underground lined gas storage facility according to claim 7, characterized in that, The strain monitoring precast slab (14) is constructed using a two-stage casting process: After the first pour is completed and cured to the design strength, optical fibers and strain gauges are attached to the concrete surface. Epoxy resin was then used to wrap and protect the optical fiber and strain gauge to prevent damage during subsequent construction. After the epoxy resin has cured, a second concrete pour is made to completely cover the sensor and form a complete strain monitoring precast panel (14).

9. A method for testing a large-scale physical model of an underground lined gas storage facility, characterized in that, The large physical model test platform for underground lined gas storage as described in any one of claims 1-8 includes the following steps: S1: Based on the simulation requirements of the mechanical properties of the surrounding rock (20) in the actual physical model test, it is necessary to first determine the similar material ratio that can accurately reflect the mechanical behavior of the real rock mass. On this basis, it is necessary to carry out mechanical property tests of uniaxial compression test and Brazilian splitting test at the same time, so as to systematically obtain the key parameters of the material's compressive strength, tensile strength, elastic modulus and Poisson's ratio, so as to comprehensively evaluate the rationality of the ratio scheme and provide a reliable material mechanics basis for subsequent similar model tests. S2: Fabricate strain monitoring precast slab (14) and arrange optical fibers and strain sensors. Use a two-stage pouring process: After the first pouring is completed and cured to the design strength, attach optical fibers and strain gauges to the concrete surface. Then wrap the optical fibers and strain gauges with epoxy resin to protect them and prevent them from being damaged in subsequent construction. After the epoxy resin is cured, pour the second concrete to completely cover the sensors and form a complete strain monitoring precast slab (14). The acoustic emission sensors of the acoustic emission monitoring device are arranged on the surface of the surrounding rock (20) of the chamber. The similar materials and proportions used in the precast slab are consistent with those of the surrounding rock (20). After the pouring is completed, curing is carried out. S3: The strain monitoring precast slab (14) is pre-installed in the designated position inside the adjustable model box (10), then the template system is erected, and the layered and segmented pouring process is adopted to simulate the material distribution and structural characteristics under actual complex geological conditions. After the pouring is completed, the formwork is removed at the specified time, and the formed concrete test block is continuously cured under standard conditions to ensure that its strength development meets the test design requirements. S4: Securely place the large rubber sealing pipe into the chamber and position it so that its outer wall is fully in contact with the rock wall of the chamber. Then, lift the heavy flange and accurately align it, and install it at the openings at both ends of the chamber. Finally, use four high-strength galvanized steel bars (21) to pull through the first flange (11) and the second flange (13), and apply pre-tightening force through the hydraulic tensioning equipment to achieve uniform and reliable anchoring seal. S5: Connect the pressurization system to the flange inlet (22) and integrate three types of monitoring equipment: strain, fiber optic and acoustic emission, to build a complete real-time monitoring network. Then, conduct systematic linkage debugging. During the test, initialize the confining pressure loading device to simulate the target stress environment. Then, set the pressure threshold and loading strategy (loading rate and number of cycles) in the loading control unit and start all monitoring equipment to collect data in real time and synchronously.

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