Ultra-low-temperature LNG underground cavern reservoir freezing simulation test device and ultra-low-temperature LNG underground cavern reservoir freezing simulation test method

Abstract

The invention discloses an ultralow-temperature LNG (Liquefied Natural Gas) underground cavern reservoir freezing simulation test device and method, and particularly relates to the field of underground energy storage. Comprising a steel frame, an overflow groove is formed in the upper side of the steel frame, a water conveying groove penetrating through the left side and the right side of the steel frame is formed in the lower side of the steel frame, a water inlet hole and a water drainage hole are formed in the two ends of the water conveying groove respectively, a rock mass model is arranged in the steel frame, and high-strength heat insulation organic glass plates are further arranged on the front side and the rear side of the steel frame; the high-strength heat insulation organic glass plate is connected with the steel frame through a fixing assembly, a sensor assembly is arranged on the high-strength heat insulation organic glass plate, the steel frame is further wrapped with a cooling cylinder embedded in the rock mass model, and the cooling cylinder is used for cooling the interior of the steel frame. By adopting the technical scheme of the invention, the problems of high difficulty and high cost of the existing cavern test are solved, and simulation of various important research objects such as surrounding rock groundwater seepage, temperature and strain field evolution, crack frost heaving expansion and ice seal ring form can be realized.

Description

Technical Field

[0001] The present invention relates to the field of underground energy storage, and in particular to an ice-sealing simulation test device and method for an ultra-low temperature LNG underground cave storage. Background Art

[0002] Liquefied Natural Gas (LNG) is a liquid that is formed when natural gas is cooled to its condensation point (about -162°C). Its volume is about 1 / 625 of the volume of the same mass of gas. It can greatly reduce the storage space and facilitate normal pressure storage, saving storage and transportation costs. The main storage methods of natural gas are ground storage tanks and underground gas storage, and underground storage has many advantages such as large capacity, economy, and high safety. The natural gas underground storage that has been successfully built and operated in the world is mainly based on depleted oil and gas reservoirs, but they are all stored at room temperature. The disadvantage is that the reserves are relatively small, and there are problems such as insufficient storage site resources and difficulty in ensuring the sealing effect. Therefore, it is an important development direction to explore the use of artificially excavated underground caves or widely distributed abandoned mines with free selection of sites to build LNG underground storage.

[0003] In order to prevent the surrounding rock of the LNG underground storage from being severely frost-heaved and deformed by the low temperature of -162℃, the surrounding rock should be drained before injecting LNG, and then LNG should be injected to cool the surrounding rock without frost-heaving damage. After the low temperature is transmitted to a certain range (i.e., the distance between the 0℃ isotherm and the storage), the drainage is stopped to allow the groundwater to flow back. When the groundwater flows back to the 0℃ isotherm, it gradually freezes, thus forming an ice ring of a certain thickness. The ice ring can block the outer groundwater from infiltrating into the inner surrounding rock and causing frost heave and rupture. Therefore, the ice ring is crucial to the success of the storage construction. However, at present, the LNG underground storage is only in the stage of shallow buried small cave test demonstration, and there is no formal construction and commissioning of the storage. One of the key reasons is that the formation mechanism and regulation technology of the ice ring still need to be studied in depth. Since the cost of using on-site cave tests is too high, a physical simulation test is urgently needed to carry out relevant research to promote the development of LNG underground storage construction technology, but so far there is a lack of simulation test equipment in this regard. Summary of the invention

[0004] The present invention aims to provide an ultra-low temperature LNG underground cave storage ice-sealing simulation test device and method, which solves the problem of high difficulty and high cost of existing cave tests.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a technical solution as follows: an ultra-low temperature LNG underground cave storage ice simulation test device, comprising a steel frame, an overflow trough with one end penetrating the steel frame is provided on the upper side of the steel frame, a water delivery trough penetrating the left and right sides of the steel frame is provided on the lower side of the steel frame, and an inlet hole and a drain hole are provided at both ends of the water delivery trough respectively, a rock model is provided inside the steel frame, and high-strength thermal insulation plexiglass plates are also provided on the front and back sides of the steel frame, the high-strength thermal insulation plexiglass plates are connected to the steel frame through a fixing component, a sensor assembly is provided on the high-strength thermal insulation plexiglass plate, and the sensor assembly is used to monitor relevant changes of the rock model, and the steel frame is also covered with a cooling cylinder embedded in the rock model, and the cooling cylinder is used to cool the inside of the steel frame.

[0006] Furthermore, the steel frame includes an upper beam, a lower beam, a left column, a right column and a base, all of which have rectangular cross-sections. The upper beam, the lower beam, the left column and the right column are combined to form a rectangular frame structure. The rectangular frame structure is fixedly connected to the base through the lower beam. The width of the base is greater than the upper beam, the lower beam, the left column and the right column. The overflow trough is arranged at the bottom of the upper beam and passes through the left column. The water delivery trough is arranged at the top of the lower beam and passes through the left column and the right column. The drainage hole is arranged on the left column, and the water inlet hole is arranged on the right column.

[0007] Furthermore, the fixing assembly includes a fixing plate and a rubber pad, the number of the fixing plates is four, the cross-sectional shape of each fixing plate is L-shaped, the four fixing plates respectively abut against the side edges of the high-strength thermal insulation plexiglass plate, the fixing plates are connected to the steel frame by bolts, the width of the rubber pad is the same as the width of the side of the fixing plate that abuts against the high-strength thermal insulation plexiglass plate, the shape of the rubber pad is a U-shape, the rubber pad is attached to the edge of the high-strength thermal insulation plexiglass plate, and the rubber pad and the fixing plate are respectively arranged on both sides of the high-strength thermal insulation plexiglass plate.

[0008] Furthermore, any one of the high-strength thermal insulation plexiglass plates is provided with four placement grooves, one end of each of the placement grooves is close to the center of the high-strength thermal insulation plexiglass plate, and the other end of each of the placement grooves passes through the side wall of the high-strength thermal insulation plexiglass plate, and the sensor assembly is arranged in the placement groove.

[0009] Furthermore, the sensor assembly includes a temperature sensor and a strain gauge.

[0010] Furthermore, the cooling cylinder is embedded in the center of the rock model, and the upper and lower sides of the cooling cylinder are respectively connected with a liquid inlet pipe and a liquid outlet pipe passing through a high-strength thermal insulation plexiglass plate. The liquid inlet pipe is connected to an external coolant injection device, and a control valve is provided on the liquid outlet pipe.

[0011] Furthermore, the rock model is provided with a first crack and a second crack connected to both the overflow trough and the water delivery trough, the first crack and the second crack are orthogonally distributed and connected to each other, the first crack and the second crack cut the surface of the rock model into a plurality of discrete blocks, each of the discrete blocks is cut with a third crack, the third crack does not pass through any two sides of the discrete block and is connected to the first crack or the second crack.

[0012] Furthermore, the test method of the test device is as follows:

[0013] S1. Fix any high-strength heat-insulating plexiglass plate to the rear side of the steel frame;

[0014] S2, placing the rock mass model and cooling cylinder into the steel frame;

[0015] S3, pasting the sensor assembly in the placement slot;

[0016] S4, fixing another high-strength heat-insulating plexiglass plate on the front side of the steel frame;

[0017] S5. After the drainage holes are blocked, water is injected into the steel frame through the water inlet holes, and the water is discharged through the drainage holes after the rock mass model is moistened;

[0018] S6. After the drainage hole and the water inlet hole are blocked, coolant is injected through the liquid inlet pipe to cool the rock model;

[0019] S7, open the water inlet hole and inject water into the steel frame, and when the water level gradually rises, the water gradually forms an ice ring when it meets the zero temperature line;

[0020] S8. Record the test process and monitor and record the data such as the amount of coolant injected, rock model temperature, rock model strain, crack expansion, water injection pressure, water level rise rate, zero temperature line and ice circle range.

[0021] Compared with the prior art, this solution has the following beneficial effects:

[0022] 1. This scheme provides a test device and method that can be used to simulate the formation process of the ice circle of ultra-low temperature LNG underground cave storage, which solves the problem of high difficulty and high cost of existing cave tests, and can realize the simulation of various important research objects such as groundwater seepage in the surrounding rock, temperature and strain field evolution, crack frost heave expansion, and ice circle morphology.

[0023] 2. This scheme provides an effective experimental means for studying the formation and regulation of the ice-sealed anti-seepage circle in the design of ultra-low temperature LNG underground cave storage. The experimental device has a simple structure, easy operation and high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is a front view of an ultra-low temperature LNG underground cave storage ice-sealing simulation test device of the present invention;

[0025] Figure 2 This is a front view of an ultra-low temperature LNG underground cave storage ice-sealing simulation test device (excluding the rock model and sensor assembly) of the present invention;

[0026] Figure 3 It is a front view of the steel frame in the embodiment;

[0027] Figure 4 for Figure 3 The view of AA in the middle;

[0028] Figure 5 for Figure 3 View of the middle BB;

[0029] Figure 6 This is a schematic diagram of the structure of the high-strength heat-insulating organic glass plate and the rubber pad located at the rear side in the embodiment;

[0030] Figure 7 This is a schematic diagram of the structure of the fixing plate at the high-strength heat-insulating organic glass plate located at the front side in the embodiment;

[0031] Figure 8 It is a schematic diagram of the three-dimensional structure of the rock mass model of the present invention;

[0032] Fig. 9 It is a schematic structural diagram of the cooling cylinder of the present invention;

[0033] Fig.10 This is a schematic diagram of the ice circle formation process during the test process of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below through specific embodiments:

[0035] The figure marks in the drawings of the specification include: steel frame 1, overflow trough 2, water delivery trough 3, water inlet hole 4, drainage hole 5, upper beam 6, lower beam 7, left column 8, right column 9, base 10, rock model 11, first crack 12, second crack 13, discrete block 14, third crack 15, cooling cylinder 16, liquid inlet pipe 17, liquid outlet pipe 18, high-strength thermal insulation plexiglass plate 19, fixing plate 20, rubber pad 21, placement groove 22, sensor assembly 23, wire 24, ice ring 25, zero temperature line 26, water level 27.

[0036] Example

[0037] like Figure 1-10As shown, an ultra-low temperature LNG underground cavern storage ice-sealing simulation test device comprises a steel frame 1, an overflow trough 2 having one end penetrating the steel frame 1 is provided on the upper side of the steel frame 1, a water delivery trough 3 penetrating the left and right sides of the steel frame 1 is provided on the lower side of the steel frame 1, and a water inlet hole 4 and a drain hole 5 are respectively provided at both ends of the water delivery trough 3. In this embodiment, the steel frame 1 comprises an upper beam 6, a lower beam 7, a left column 8, a right column 9 and a base 10, all of which have rectangular cross sections. The upper beam 6, the lower beam 7, the left column 8 and the right column 9 enclose a rectangular frame structure, and the internal space size of the rectangular frame structure is 1500mm×1500mm×100mm. The rectangular frame structure is fixedly connected to the base 10 through the lower beam 7, and the width of the base 10 is greater than the upper beam 6, the lower beam 7, the left column 8 and the right column 9. The overflow trough 2 and the water delivery trough 3 are both U-shaped. The overflow trough 2 is set at the bottom of the upper beam 6 and passes through the left column 8. The overflow trough 2 is always open. When the water in the rock model 11 is too full, water can overflow freely through the overflow trough 2. The water delivery trough 3 is set on the top of the lower beam 7 and passes through the left column 8 and the right column 9. The drainage hole 5 is set on the left column 8, and the water inlet hole 4 is set on the right column 9. The water inlet and outlet channels are formed by the water inlet hole 4, the output trough and the drainage hole 5. When water needs to be inlet, the drainage hole 5 is closed and the water inlet hole 4 is opened to inject water. At this time, the water level 27 in the rock model 11 rises. When drainage is required, the water inlet hole 4 is closed and the drainage outlet of the left column 8 is opened to drain water, and the water level 27 in the rock model 11 drops.

[0038] A rock model 11 is provided inside the steel frame 1. The size of the rock model 11 is the same as the size of the internal space of the steel frame 1. In this embodiment, the rock model 11 can be cut and processed from real rock blocks, or it can be cast and cut using cement mortar or similar materials. In order to allow the water in the rock model 11 to have a flow channel and facilitate the formation of an ice ring 25, the rock model 11 is provided with a first crack 12 and a second crack 13 that are connected to the overflow trough 2 and the water delivery trough 3. The first crack 12 and the second crack 13 are orthogonally distributed and connected to each other. The spacing between two adjacent first cracks 12 is 300 mm, and the spacing between two adjacent second cracks 13 is 100 mm. The first crack 12 and the second crack 13 cut a plurality of discrete blocks 14 on the surface of the rock model 11. Each discrete block 14 is cut with a third crack 15. The third crack 15 does not penetrate any two sides of the discrete block and is connected to the first crack 12 or the second crack 13. In this embodiment, the depths of the first crack 12, the second crack 13 and the third crack 15 are all 100 mm. A circular cross-sectional space with a diameter of 200 mm is cut out from the center of the rock model 11. A cooling cylinder 16 is placed in the circular cross-sectional space. The cooling cylinder 16 is a steel cylindrical cylinder with a diameter of 200 mm and a height of 100 mm. The upper and lower sides of the cooling cylinder 16 are respectively connected with a liquid inlet pipe 17 and a liquid outlet pipe 18 passing through a high-strength heat-insulating organic glass plate 19. The high-strength heat-insulating organic glass plate 19 located at the front side is provided with a through hole for the liquid inlet pipe 17 and the liquid outlet pipe 18 to pass through. The liquid inlet pipe 17 and the liquid outlet pipe 18 are sealed with hot melt adhesive between the through holes; the liquid inlet pipe 17 is connected to the external coolant injection device, and the liquid outlet pipe 18 is provided with a control valve. The injection amount of the coolant can be adjusted by means of the liquid inlet pipe 17 and the liquid outlet pipe 18, so as to adjust the conduction range of the low temperature in the rock model 11. In this embodiment, in order to simulate the ultra-low temperature of LNG, liquid nitrogen is used as the coolant.

[0039] On the front and back sides of the steel frame 1, high-strength heat-insulating organic glass plates 19 are also provided, and the high-strength heat-insulating organic glass plates 19 are connected to the steel frame 1 through fixing components. The fixing components include fixing plates 20 and rubber pads 21. The number of the fixing plates 20 is four. The cross-sectional shape of each fixing plate 20 is L-shaped. The thinner sides of the four fixing plates 20 respectively abut against the side edges of the high-strength heat-insulating organic glass plate 19. A plurality of round holes are provided on the thicker side of each fixing plate 20, and threaded holes are provided at the corresponding positions on the steel frame 1. The fixing plate 20 is connected to the steel frame 1 through bolts and the threaded holes. The thickness of the rubber pad 21 is 1 mm, and the width is the same as the width of the thin part of the fixing plate 20. The shape of the rubber pad 21 is a square frame shape. The rubber pad 21 is attached to the edge of the high-strength heat-insulating organic glass plate 19. By means of the rubber pad 21, the dual functions of uniform stress fixation and sealing of the high-strength heat-insulating organic glass plate 19 can be achieved. The rubber pad 21 and the fixing plate 20 are respectively arranged on both sides of the high-strength heat-insulating organic glass plate 19. Four placing grooves 22 are formed in the front high-strength heat-insulating organic glass plate 19. One end of each placing groove 22 is close to the center of the high-strength heat-insulating organic glass plate 19, and the other end of each placing groove 22 penetrates through the side wall of the high-strength heat-insulating organic glass plate 19. The four placing grooves 22 respectively penetrate through the centers of the four sides of the high-strength heat-insulating organic glass plate 19. A sensor assembly 23 is arranged in the placing groove 22. The sensor assembly 23 is used for monitoring relevant changes of the rock mass model 11. The sensor assembly 23 and the wire 24 are arranged along the horizontal axis and the vertical axis on the front side of the rock mass model 11 and are arranged in the space of the placing groove 22 of the high-strength heat-insulating organic glass plate 19. After the wire 24 extends out of the placing groove 22, the end of the placing groove 22 is sealed with hot melt adhesive. The sensor is connected to the data acquisition device through the wire 24. In this embodiment, the sensor assembly 23 includes a temperature sensor and a strain gauge, and is used for measuring the temperature and deformation of the rock mass model 11. At the same time, the difference between the fixing component on the front side and the fixing component on the back side is only that: through grooves for the wire 24 to pass through are formed in the fixing plates 20 of the fixing component on the front side.

[0040] The test method of the test device is as follows:

[0041] S1. Fix the high-strength heat-insulating organic glass plate 19 without the placing groove 22 on the back side of the steel frame 1 through the fixing plate 20, bolts and the rubber pad 21.

[0042] S2. Cut a rock mass model 11 from sandstone with uniform texture. Place the processed rock mass model 11 in the steel frame 1. Stack the blocks row by row from bottom to top. When stacking to the position where the cooling cylinder 16 is located, place the cooling cylinder 16, and then stack the blocks row by row until the entire rock mass model 11 is stacked.

[0043] S3. Paste the temperature sensor and strain gauge along the front horizontal axis and vertical axis of the rock model 11, starting from the vicinity of the cooling cylinder 16 and alternately pasting them to the edge of the rock model 11, and straighten the sensor wire 24, and fix it along the front horizontal axis and vertical axis of the rock model 11 with transparent tape. When the high-strength heat-insulating plexiglass plate 19 located on the front side is subsequently installed, the temperature sensor, strain gauge and wire 24 are located in the placement groove 22.

[0044] S4. Fix the high-strength heat-insulating organic glass plate 19 with the placement groove 22 on the steel frame 1 through the fixing plate 20, bolts and rubber pads 21, and use hot melt adhesive to seal the ends of the placement groove 22 and the gaps between the liquid inlet pipe 17, the liquid outlet pipe 18 and the through hole.

[0045] S5, after installation is completed, close the drainage hole 5, open the water inlet hole 4 to inject water into the rock model 11, fill it with water for 6 hours to make the rock model 11 fully moist, then close the water inlet hole 4, open the drainage hole 5 to drain the water in the rock model 11. This step simulates the process of draining groundwater from the surrounding rock near the LNG underground reservoir before injecting LNG.

[0046] S6. After draining the water, inject coolant (liquid nitrogen is used as coolant in this test) and wait for the cooling range of the rock model 11 to stabilize (i.e., the zero temperature line 26 no longer moves outward). This step simulates the conduction process of low temperature in the surrounding rock after the groundwater in the surrounding rock near the LNG underground reservoir is drained and LNG is injected into the reservoir.

[0047] S7. Water is injected into the rock model 11 again to gradually raise the water level 27. When the water level 27 meets the zero temperature line 26, it starts to freeze and freezes within a certain range toward the cooling cylinder 16, gradually forming an ice circle 25. The cracks in the rock model 11 within the ice circle 25 will not freeze because there is no water. This step simulates the formation process of the ice circle 25 outside the LNG underground reservoir. The ice circle 25 can block the groundwater from infiltrating into the vicinity of the reservoir and causing frost heave damage to the surrounding rocks, thereby protecting the structure and sealing safety of the reservoir.

[0048] S8. The test process is recorded, and the data such as the amount of coolant injected, the temperature of the rock model 11, the strain of the rock model 11, the amount of crack expansion, the water injection pressure, the rate of increase of the water level 27, the zero temperature line 26 and the range of the ice circle 25 are monitored and recorded, wherein the amount of coolant injected is set before injection; the temperature of the rock model 11 is monitored by a temperature sensor; the strain of the rock model 11 is monitored by a strain sensor; the crack expansion can be identified in the high-definition photo and the extension length can be measured; the water injection pressure can be adjusted by a water pump; the rate of increase of the water level 27 is calculated by measuring the final water level 27 and the water injection time (i.e., the final water level 27 divided by the water injection time); the zero temperature line 26 is determined by the temperature field measured by the temperature sensor; the range of the ice circle 25 can be observed and determined in the high-definition photo.

[0049] The above are only embodiments of the present invention, and the common knowledge such as the known specific structures and / or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An ultra-low temperature LNG underground cavern storage ice-sealing simulation test device, Features: It comprises a steel frame, wherein an overflow trough with one end penetrating the steel frame is provided on the upper side of the steel frame, a water delivery trough penetrating the left and right sides of the steel frame is provided on the lower side of the steel frame, a water inlet hole and a drainage hole are provided at both ends of the water delivery trough respectively, a rock model is provided inside the steel frame, a high-strength heat-insulating organic glass plate is provided on the front and rear sides of the steel frame, the high-strength heat-insulating organic glass plate is connected to the steel frame through a fixing component, a sensor component is provided on the high-strength heat-insulating organic glass plate, the sensor component is used to monitor relevant changes of the rock model, and the steel frame is also covered with a cooling cylinder embedded in the rock model, and the cooling cylinder is used to cool the inside of the steel frame.

2. According to claim 1, an ultra-low temperature LNG underground cavern storage ice sealing simulation test device, Features: The steel frame includes an upper beam, a lower beam, a left column, a right column and a base, all of which have rectangular cross-sections. The upper beam, the lower beam, the left column and the right column enclose a rectangular frame structure, and the rectangular frame structure is fixedly connected to the base through the lower beam. The width of the base is greater than the upper beam, the lower beam, the left column and the right column. The overflow trough is arranged at the bottom of the upper beam and passes through the left column. The water delivery trough is arranged at the top of the lower beam and passes through the left column and the right column. The drainage hole is arranged on the left column, and the water inlet hole is arranged on the right column.

3. According to claim 1, an ultra-low temperature LNG underground cavern storage ice sealing simulation test device, Features: The fixing assembly includes a fixing plate and a rubber pad, and there are four fixing plates, each of which has an L-shaped cross-sectional shape. The four fixing plates respectively abut against the side edges of the high-strength thermal insulation plexiglass plate, and the fixing plates are connected to the steel frame by bolts. The width of the rubber pad is the same as the width of the side of the fixing plate that abuts against the high-strength thermal insulation plexiglass plate, and the shape of the rubber pad is a U-shape, and the rubber pad is attached to the edge of the high-strength thermal insulation plexiglass plate, and the rubber pad and the fixing plate are respectively arranged on both sides of the high-strength thermal insulation plexiglass plate.

4. The ultra-low temperature LNG underground cavern storage ice sealing simulation test device according to claim 1, Features: Four placement grooves are provided on any of the high-strength thermal insulation plexiglass plates, one end of each of the placement grooves is close to the center of the high-strength thermal insulation plexiglass plate, and the other end of each of the placement grooves passes through the side wall of the high-strength thermal insulation plexiglass plate, and the sensor assembly is arranged in the placement groove.

5. The ultra-low temperature LNG underground cavern storage ice sealing simulation test device according to claim 4, Features: The sensor assembly includes a temperature sensor and a strain gauge.

6. The ultra-low temperature LNG underground cavern storage ice sealing simulation test device according to claim 1, Features: The cooling cylinder is embedded in the center of the rock model. The upper and lower sides of the cooling cylinder are respectively connected with a liquid inlet pipe and a liquid outlet pipe passing through a high-strength heat-insulating organic glass plate. The liquid inlet pipe is connected to an external coolant injection device, and a control valve is provided on the liquid outlet pipe.

7. The ultra-low temperature LNG underground cavern storage ice sealing simulation test device according to claim 1, Features: The rock model is provided with a first crack and a second crack which are connected to both the overflow trough and the water delivery trough. The first crack and the second crack are orthogonally distributed and connected to each other. The first crack and the second crack cut the surface of the rock model into a plurality of discrete blocks. A third crack is cut on each of the discrete blocks. The third crack does not pass through any two sides of the discrete block and is connected to the first crack or the second crack.

8. An ultra-low temperature LNG underground cavern storage ice-sealing simulation test device according to any one of claims 1 to 7, Features: The test method of the test device is as follows: S1. Fix any high-strength heat-insulating plexiglass plate to the rear side of the steel frame; S2, placing the rock mass model and cooling cylinder into the steel frame; S3, pasting the sensor assembly in the placement slot; S4, fixing another high-strength heat-insulating plexiglass plate on the front side of the steel frame; S5. After the drainage holes are blocked, water is injected into the steel frame through the water inlet holes, and the water is discharged through the drainage holes after the rock mass model is moistened; S6. After the drainage hole and the water inlet hole are blocked, coolant is injected through the liquid inlet pipe to cool the rock model; S7, open the water inlet hole and inject water into the steel frame, and when the water level gradually rises, the water gradually forms an ice ring when it meets the zero temperature line; S8. Record the test process and monitor and record the data such as the amount of coolant injected, rock model temperature, rock model strain, crack expansion, water injection pressure, water level rise rate, zero temperature line and ice circle range.

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