Underwater CO2 rock breaking safety distance prediction method and device based on biological damage threshold value
By establishing an attenuation model of underwater supercritical CO2 phase change pulses that varies with distance and the relationship between the critical wave pressure for fish safety, the issue of fish safety during underwater reef clearing using supercritical CO2 was resolved, and accurate prediction and protection of fish safety distances were achieved.
Patent Information
- Application Number
- CN202510834578.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-20
- Publication Date
- 2025-09-23
AI Technical Summary
When using the supercritical CO2 underwater phase change pulse method for underwater reef clearing, the high-pressure gas affects the life safety of surrounding fish, leading to fish safety problems and low prediction accuracy.
By studying the relationship between supercritical CO2 phase change pulse pressure and the safe activity range of fish, an attenuation model of underwater supercritical CO2 phase change pulses that changes with distance is established. Combined with the safety critical wave pressure of fish, the safety critical distance of fish of different body lengths is obtained, and protective nets are used to protect the safety of fish.
The prediction accuracy of fish safety distance is improved, ensuring the safety of fish under supercritical CO2 phase change pulses and protecting fish in ecologically sensitive areas from damage.
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Figure CN120688400A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of ecological protection technology, and in particular to a method and device for predicting underwater CO2 rock-breaking safety distance based on biological damage thresholds. Background Art
[0002] With the advancement of waterway regulation projects and the deepening of ecological awareness, supercritical CO2 underwater phase-change rock breaking (a non-explosive physical rock breaking method) has been applied to underwater reef clearing. This method uses a chemical activator to heat liquid CO2 in a sealed tube, causing it to transform into a gas. This high-pressure gas is then generated for rock fracturing. This method achieves efficient reef fragmentation without explosives, offering advantages such as controlled energy release and no chemical residue.
[0003] Although the supercritical CO2 underwater phase change rock breaking method can achieve underwater reef clearing in ecological waterways, the high-pressure gas generated when using this method for underwater reef clearing will affect the surrounding organisms, thereby causing life safety problems for fish. Summary of the Invention
[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a method and device for predicting the safe distance for underwater CO2 rock breaking based on biological damage thresholds. By studying the relationship between the supercritical CO2 phase change pulse pressure and the safe activity range of fish, the present invention solves the fish safety problems caused by underwater reef clearing using the supercritical CO2 phase change pulse method and improves the accuracy of fish safety distance prediction.
[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: The underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold includes the following steps: S1. When a supercritical CO2 phase change pulse acts on a reef, the radial stress of the reef at different resistance line lengths is obtained. Combined with the attenuation law of the supercritical CO2 phase change pulse underwater, an attenuation model of the underwater supercritical CO2 phase change pulse as it changes with distance is established. S2. Acquire underwater pulse measured data and perform regression analysis on the model parameters of the attenuation model to generate optimal model parameters and an optimal attenuation model of the underwater supercritical CO2 phase change pulse varying with distance; S3. Based on the optimal attenuation model of underwater supercritical CO2 phase change pulses that varies with distance, and combined with the safety critical wave pressure of fish, the safety critical distance of fish of different body lengths under supercritical CO2 phase change pulses is obtained.
[0006] A supercritical CO2 underwater rock breaking device for collecting underwater pulse measurement data, comprising: The CO2 filling component is used to store liquid CO2 and control the filling temperature and pressure of the liquid CO2. When the filling temperature and pressure of the liquid CO2 reach the set thresholds, the liquid CO2 is in a supercritical state. Underwater fracturing assembly, used to stimulate the release of supercritical CO2 energy through blasting operation when liquid CO2 is in a supercritical state, generating supercritical CO2 phase change pulse peak pressure; The pulse monitoring component is used to collect real-time pulse transmission stress in water at different resistance line lengths and distances of the reef under the action of supercritical CO2 phase change pulse peak pressure, and generate underwater pulse measurement data.
[0007] The present invention has the following beneficial effects: The method and device for predicting the safe distance for underwater CO2 rock breaking based on biological damage threshold proposed in the present invention construct an attenuation model of underwater supercritical CO2 phase change pulses that varies with distance based on the attenuation law of supercritical CO2 phase change pulses underwater, obtain underwater pulse measured data through a rock breaking device, and then use the least squares method to perform regression analysis on the model parameters to obtain the optimal values of the model parameters, thereby generating an optimal attenuation model of underwater supercritical CO2 phase change pulses that varies with distance. Combined with the safety critical wave pressure of fish, the safe critical distance of fish of different body lengths under supercritical CO2 phase change pulses is accurately predicted. At the same time, according to the predicted safe critical distance, when using supercritical CO2 phase change pulses to clear reefs, a protective net can be set up to protect the safety of fish in ecologically sensitive areas. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 This is a flow chart of the underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold proposed in the present invention; Figure 2 Schematic diagram of the relationship between fish body length and safety critical wave pressure in the embodiment; Figure 3 Schematic diagram of the structure of the supercritical CO2 underwater rock breaking device in the embodiment; Figure 4 Schematic diagram of the CO2 fracturing system structure in the embodiment. DETAILED DESCRIPTION
[0009] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.
[0010] like Figure 1As shown, the underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold includes the following steps S1-S3: S1. When a supercritical CO2 phase change pulse acts on a reef, the radial stress of the reef at different resistance line lengths is obtained. Combined with the attenuation law of the supercritical CO2 phase change pulse underwater, an attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance is established.
[0011] Specifically, step S1 includes S11-S16: S11. When the supercritical CO2 phase change pulse acts on the reef, calculate the supercritical CO2 phase change pulse peak pressure, that is:
[0012] in, Indicates the supercritical CO2 phase change pulse peak pressure, in MPa, Indicates the shear strength of the cracked pipe, in MPa. Indicates the thickness of the cracking pipe, in mm. Indicates the radius of the fracture tube, in mm.
[0013] S12. Considering the transient pressurization effect of the supercritical CO2 phase change pulse peak pressure acting on the crack wall of the reef, calculate the incident stress of the reef wall, that is:
[0014] in, Represents the incident stress on the reef hole wall, in MPa. It indicates the increase factor of supercritical CO2 phase change pulse peak pressure, which is generally taken as 10. Indicates the radius of the crack hole, in mm.
[0015] S13. When the peak pressure of the supercritical CO2 phase change pulse reaches the rock breaking condition, calculate the radial stress of the reef under different resistance line lengths, that is:
[0016]
[0017]
[0018]
[0019] in, Indicates the ratio of distance, It indicates the length of the reef resistance line, that is, the minimum distance from the central drilling hole of the reef to the free surface of the reef. represents the attenuation coefficient of the reef rock mass, represents the reef Poisson's ratio, Indicates the length of the reef resistance line The radial stress of the reef under the φ is in MPa.
[0020] S14. When the pulse reaches the water-rock interface, transreflection occurs. Based on the principle that the transmitted pulse continues to propagate in the water, the pulse transmission coefficient is introduced to describe the pulse transmission process of the supercritical CO2 phase change pulse at the interface between the reef and the water. The pulse transmission stress formula in water is established, namely:
[0021]
[0022]
[0023] in, represents the pulse transmission coefficient, 、 Represent water density and reef density respectively. 、 Represent the propagation speed of the pulse in water and reef respectively, represents the wave impedance of the water body, represents the wave impedance of the reef, It represents the pulse transmission stress in water, that is, the initial stress transmitted from the reef to the water, and its unit is MPa.
[0024] S15. Establish an empirical formula for explosive blasting pulse attenuation to describe the attenuation law of supercritical CO2 phase change pulse underwater, namely:
[0025]
[0026]
[0027] in, It represents the distance from the underwater pulse monitoring point to the crack hole, in meters. Indicates the length of the reef resistance line Pulse transmission stress in water at different distances, 、 represent the pulse attenuation coefficient and attenuation exponent, respectively. Indicates the charge quantity in kg. Indicates the supercritical CO2 pulse energy in kJ, It represents the explosive quantity of emulsion explosive per unit reef, and its value is 4250 kJ. represents the volume of the fracture tube, Indicates the adiabatic index of the gas, which is generally taken as 1.3. Indicates atmospheric pressure, generally taken as 0.10325 MPa.
[0028] In this embodiment, the pulse attenuation coefficient With decay index The specific value of needs to be fitted through the test data of step S2 to obtain the optimal value. In addition, the fracturing tube can be a 85-type fracturing tube with a volume of 0.00157 m 3 In addition, the monitoring points refer to the locations where water pressure sensors are arranged, and the monitoring points are 1, 3, 5, 7, and 9 meters away from the boreholes, respectively, and are arranged linearly along the water tank.
[0029] S16. Establish an attenuation model for underwater supercritical CO2 phase change pulses as they change with distance, namely: .
[0030] In this embodiment, an attenuation model of an underwater supercritical CO2 phase change pulse that varies with distance is established in order to obtain the attenuation of the supercritical CO2 phase change pulse underwater at a theoretical level.
[0031] S2. Acquire underwater pulse measured data and perform regression analysis on the model parameters of the attenuation model to generate optimal model parameters and an optimal attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance.
[0032] In this embodiment, a supercritical CO2 underwater rock breaking test was carried out, and underwater pulse measured data was obtained using a TP-SJB-5M water pressure sensor and a Blast-PRO pulse tester to adjust the model parameters. 、 Perform regression analysis.
[0033] Specifically, step S2 includes S21-S24: S21. Collect underwater pulse measurement data, which includes underwater pulse transmission stress at different distances and different resistance line lengths of the reef.
[0034] In this embodiment, the process of collecting underwater pulse measured data is as follows: Firstly, a supercritical CO2 underwater rock breaking test was carried out using a supercritical CO2 underwater rock breaking device. The device mainly consists of three parts: a CO2 filling component, an underwater fracturing component, and a pulse monitoring component. Among them, the CO2 filling component mainly consists of a liquid CO2 gas cylinder (CO2 storage tank), a booster pump, a chiller, and a pressure and temperature control system, which can realize the storage, compression, pressure and temperature control, and filling of CO2; the underwater fracturing component mainly consists of a fracturing tube, an activator, an initiator (CHA-2000E initiator), and a protective device; the underwater pulse monitoring component includes a TP-SJB-5M water pressure sensor (range: ±1 V / ±10 V, maximum sampling rate: 4 MHz), a Blast-PRO pulse tester, and a computer.
[0035] Secondly, the test rock sample was selected from the original limestone cut from the reef clearing site. The rock sample was taken from Jiangjin District, Chongqing, and belongs to the Jialingjiang Formation limestone. Its density is 2770 kg / m 3 , Poisson's ratio is 0.25, elastic modulus is 20.56 GPa, uniaxial tensile strength and compressive strength are 8.43 MPa and 78.55 MPa, respectively.
[0036] Before the test, the limestone was processed into specimens measuring 500 × 500 × 500 mm. To reserve the fracture site, a 100 mm diameter and 250 mm deep fracture hole was drilled in the center of the limestone top. After the specimen was immersed in water, the fracture tube was placed into the fracture hole and secured with a protective device. The protective device consisted of a cylindrical iron barrel (2 m diameter, 12 mm wall thickness, 1.7 t weight), an iron chain, and a fracture tube stopper to prevent the fracture tube from flying out.
[0037] The test steps include the following aspects: (1) Sample preparation: After the standardized cut limestone sample is processed through the central drilling, the sample is slowly immersed in water using a sling to ensure that the sample is in full contact with the water body and to avoid air bubble interference. (2) System connection: Connect the TP-SJB-5M water pressure sensor to the Blast-PRO pulse tester, set the acquisition frequency (4 MHz) and related parameters, and at the same time, use a protective device to fix the fracturing tube and check the integrity of the fracturing tube circuit and the installation of the energy release plate. (3) Test implementation: Supercritical CO2 is injected into the fracturing tube, and the pressure is controlled within 10 MPa. When the fracturing tube is detonated, the water pressure sensor is used to record the underwater pulse transmission stress at different distances and different resistance line lengths of the reef.
[0038] S22, set initialization parameters, including the explosion amount of unit reef emulsion explosives , Pulse transmission stress in water , the volume of the fractured tube , adiabatic index of gas .
[0039] S23. Based on the underwater pulse measured data and initialization parameters, the least squares method is used to perform regression analysis on the pulse attenuation coefficient and attenuation index to obtain the optimal pulse attenuation coefficient and attenuation index.
[0040] In this embodiment, the optimal pulse attenuation coefficient and attenuation index are finally obtained: 、 .
[0041] S24. Substitute the optimal pulse attenuation coefficient and attenuation exponent into the attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance to generate the optimal attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance.
[0042] In this embodiment, the optimal value 、 Substitute the attenuation model of underwater supercritical CO2 phase change pulse with distance: The optimal attenuation model of underwater supercritical CO2 phase change pulse with distance is obtained, namely: .
[0043] S3. Based on the optimal attenuation model of underwater supercritical CO2 phase change pulses that varies with distance, and combined with the safety critical wave pressure of fish, the safety critical distance of fish of different body lengths under supercritical CO2 phase change pulses is obtained.
[0044] Specifically, step S3 includes S31-S32: S31. Calculate the critical wave pressure for fish safety, namely:
[0045] in, Indicates the critical wave pressure for fish safety, It represents the wave impedance ratio between the fish body medium and the swim bladder wall medium, Represents the fish body shape factor, 、 、 Respectively represent the swim bladder width factor, swim bladder wall thickness factor, and swim bladder critical tensile stress factor, 、 、 Respectively represent the swim bladder width index, swim bladder wall thickness index, and swim bladder critical tensile stress index, Indicates the length of the fish body.
[0046] In this embodiment, according to existing research, the measured crucian carp parameters in the Yangtze River channel are obtained, and the swim bladder width factor is ,index ; Swim bladder wall thickness factor ,index ; Radial critical tensile stress factor of swim bladder ,index ; Wave impedance ratio of fish body medium and swim bladder wall medium Fish body shape factors .
[0047] S32. Based on the critical wave pressure of fish safety and combined with the optimal attenuation model of underwater supercritical CO2 phase change pulse that varies with distance, the critical safety distance of fish of different body lengths under supercritical CO2 phase change pulse is obtained.
[0048] In this embodiment, the calculation formula for the critical wave pressure for fish safety is: The optimal attenuation model of underwater supercritical CO2 phase change pulse with distance obtained above is: , make , then: , Therefore, based on this formula, when the measured fish parameters are obtained, the safety critical distance of fish at different body lengths can be obtained by substituting the measured fish parameters. In this way, according to the calculated safety critical distance, a protective net can be set up during underwater reef clearing to protect the safety of fish in ecologically sensitive areas. Among them, the relationship curve between fish body length and safety critical wave pressure is as follows: Figure 2 As shown, it shows the safety critical wave pressure relationship of fish with a body length of 100-600 mm (a point is taken every 50 mm) under the action of supercritical CO2 phase change pulse.
[0049] like Figure 3 As shown, a supercritical CO2 underwater rock breaking device is used to collect underwater pulse measurement data, including: The CO2 filling component is used to store liquid CO2 and control the filling temperature and pressure of the liquid CO2. When the filling temperature and pressure of the liquid CO2 reach the set thresholds respectively, the liquid CO2 is in a supercritical state.
[0050] Specifically, the CO2 filling assembly includes a liquid CO2 gas cylinder 1, a workbench 2, a temperature and pressure control center 3, a display 4, a valve 5, a booster pump 6, and a chiller 7; Liquid CO2 gas cylinders are used to store liquid CO2.
[0051] The workbench is used to place various components, temperature and pressure control center.
[0052] The temperature and pressure control center is used to control the filling temperature and pressure of liquid CO2 in the liquid CO2 storage cylinder by controlling the booster pump and the chiller respectively.
[0053] A display is used to display the filling temperature and pressure of liquid CO2 in the liquid CO2 storage cylinder.
[0054] Valve, used to control the opening and closing of liquid CO2 storage cylinders.
[0055] Booster pump, used to pressurize liquid CO2 storage cylinders.
[0056] Chiller, used to regulate the temperature of liquid CO2 storage cylinders.
[0057] The underwater fracturing assembly is used to stimulate the release of supercritical CO2 energy through blasting operation when the liquid CO2 is in a supercritical state, thereby generating a supercritical CO2 phase change pulse peak pressure.
[0058] In this embodiment, when the temperature and pressure in the fracturing tube reach 31.1°C and 7.38 MPa, respectively, the liquid CO2 in the fracturing tube reaches a supercritical state. At this time, a detonator is used to trigger the explosion of the explosive pack in the fracturing tube, thereby instantly releasing the energy accumulated in the supercritical liquid CO2 to generate a supercritical CO2 phase change pulse pressure.
[0059] Specifically, the underwater fracturing assembly includes a test rock sample 9-5, a test water tank 8, a fracturing tube 9-1, a protective device, and a detonator 10; The test water tank is used as a test site for supercritical CO2 phase change pulses and is used to place test rock samples.
[0060] Test rock samples are used to generate fracturing holes through the center drilling, and the fracturing tubes are placed through the fracturing holes.
[0061] Fracturing tube, used to receive supercritical CO2.
[0062] In this embodiment, an explosive pack is placed in the fracturing tube. When an initiator, such as a CHA-2000E initiator, detonates the explosive pack, the energy accumulated in the supercritical CO2 is released instantaneously, generating a supercritical CO2 phase change pulse peak pressure.
[0063] The detonator is used to detonate the supercritical CO2 in the fracturing tube and generate a supercritical CO2 phase change pulse peak pressure in the fracturing tube.
[0064] In this embodiment, the protective device includes a crack pipe limiter 9-2, an iron chain 9-3, and a cylindrical protective iron barrel 9-4. Figure 3 9 in the middle is the CO2 fracturing system, which includes a fracturing pipe 9-1, a test rock sample 9-5 and a protective device.
[0065] Specifically, the protective device includes a crack pipe limiter 9-2, an iron chain 9-3, and a cylindrical protective iron barrel 9-4.
[0066] The fracture tube limiter is used to fix the position of the fracture tube.
[0067] In this embodiment, the fracturing tube stopper is composed of two U-shaped iron blocks, and the purpose of fixing the position of the fracturing tube is to prevent the fracturing tube from flying upward.
[0068] Cylindrical iron barrel, used to wrap and fix the position of test rock samples.
[0069] In this embodiment, the purpose of wrapping and fixing the test rock sample in the cylindrical iron barrel is to prevent the test rock sample from flying out after being broken.
[0070] Iron chains are used to fix the position of fracturing tubes and test rock samples.
[0071] In this embodiment, the purpose of fixing the position of the fracturing tube and the test rock sample with the iron chain is to prevent the fracturing tube from flying out.
[0072] The pulse monitoring component is used to collect real-time pulse transmission stress in water at different resistance line lengths and distances of the reef under the action of supercritical CO2 phase change pulse peak pressure, and generate underwater pulse measurement data.
[0073] Specifically, the pulse monitoring component includes a Blast-PRO pulse tester 11 and a TP-SJB-5M water pressure sensor 12 .
[0074] The TP-SJB-5M water pressure sensor is used to collect underwater pulse transmission stress at different distances and lengths of different resistance lines on the reef when blasting occurs.
[0075] The Blast-PRO pulse tester is used to display the underwater pulse transmission stress at different distances from the derived reef at different resistance line lengths.
[0076] In summary, the method and device for predicting the safe distance for underwater CO2 rock breaking based on biological damage threshold proposed in the present invention, based on the attenuation law of supercritical CO2 phase change pulses underwater, construct an attenuation model of underwater supercritical CO2 phase change pulses that changes with distance, and obtain underwater pulse measured data through a rock breaking device. Then, the least squares method is used to perform regression analysis on the model parameters to obtain the optimal values of the model parameters, thereby generating the optimal attenuation model of underwater supercritical CO2 phase change pulses that changes with distance. Combined with the safety critical wave pressure of fish, the safe critical distance of fish with different body lengths under supercritical CO2 phase change pulses is accurately predicted. At the same time, according to the predicted safe critical distance, when using supercritical CO2 phase change pulses to clear reefs, a protective net can be set up to protect the safety of fish in ecologically sensitive areas.
[0077] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.
[0078] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.
Claims
1. A method for predicting underwater CO2 rock-breaking safety distance based on biological damage threshold, characterized by: The following steps are involved: S1. When a supercritical CO2 phase change pulse acts on a reef, the radial stress of the reef at different resistance line lengths is obtained. Combined with the attenuation law of the supercritical CO2 phase change pulse underwater, an attenuation model of the underwater supercritical CO2 phase change pulse as it changes with distance is established. S2. Acquire underwater pulse measured data and perform regression analysis on the model parameters of the attenuation model to generate optimal model parameters and an optimal attenuation model of the underwater supercritical CO2 phase change pulse varying with distance; S3. Based on the optimal attenuation model of underwater supercritical CO2 phase change pulses that varies with distance, and combined with the safety critical wave pressure of fish, the safety critical distance of fish of different body lengths under supercritical CO2 phase change pulses is obtained.
2. The underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold according to claim 1 is characterized in that: Step S1 specifically includes: S11. When the supercritical CO2 phase change pulse acts on the reef, calculate the supercritical CO2 phase change pulse peak pressure, that is: in, represents the supercritical CO2 phase change pulse peak pressure, Indicates the shear strength of the cracked pipe, Indicates the thickness of the fracture tube, represents the radius of the fracture tube; S12. Considering the transient pressurization effect of the supercritical CO2 phase change pulse peak pressure acting on the crack wall of the reef, calculate the incident stress of the reef wall, that is: in, represents the incident stress on the reef pore wall, Indicates the increase in the peak pressure of supercritical CO2 phase change pulse, represents the radius of the rupture hole; S13. When the peak pressure of the supercritical CO2 phase change pulse reaches the rock breaking condition, calculate the radial stress of the reef under different resistance line lengths, that is: in, Indicates the ratio of distance, Indicates the length of the reef resistance line, represents the attenuation coefficient of the reef rock mass, represents the reef Poisson's ratio, Indicates the length of the reef resistance line radial stress of the reef below; S14. When the pulse reaches the water-rock interface, transreflection occurs. Based on the principle that the transmitted pulse continues to propagate in the water, the pulse transmission coefficient is introduced to describe the pulse transmission process of the supercritical CO2 phase change pulse at the interface between the reef and the water. The pulse transmission stress formula in water is established, namely: in, represents the pulse transmission coefficient, 、 Represent water density and reef density respectively. 、 Represent the propagation speed of the pulse in water and reef respectively, represents the wave impedance of the water body, represents the wave impedance of the reef, represents the pulse transmission stress in water; S15. Establish an empirical formula for explosive blasting pulse attenuation to describe the attenuation law of supercritical CO2 phase change pulse underwater, namely: in, Indicates the distance from the underwater pulse monitoring point to the crack hole, Indicates the length of the reef resistance line Pulse transmission stress in water at different distances, 、 represent the pulse attenuation coefficient and attenuation exponent, respectively. Indicates the charge amount, represents the supercritical CO2 pulse energy, Indicates the explosive quantity of unit reef emulsion explosive, represents the volume of the fracture tube, represents the adiabatic index of the gas, Indicates atmospheric pressure; S16. Establish an attenuation model for underwater supercritical CO2 phase change pulses as they change with distance, namely: 。 3. The underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold according to claim 2 is characterized in that: Step S2 specifically includes: S21, collecting underwater pulse measured data, including underwater pulse transmission stress at different distances and lengths of different resistance lines of the reef; S22, set initialization parameters, including the explosion amount of unit reef emulsion explosives , Pulse transmission stress in water , the volume of the fractured tube , adiabatic index of gas ; S23. Based on the underwater pulse measured data and the initialization parameters, a least squares method is used to perform regression analysis on the pulse attenuation coefficient and attenuation index to obtain the optimal pulse attenuation coefficient and attenuation index; S24. Substitute the optimal pulse attenuation coefficient and attenuation exponent into the attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance to generate the optimal attenuation model of the underwater supercritical CO2 phase change pulse that varies with distance.
4. The underwater CO2 rock-breaking safety distance prediction method based on biological damage threshold according to claim 3 is characterized in that: Step S3 specifically includes: S31. Calculate the critical wave pressure for fish safety, namely: in, Indicates the critical wave pressure for fish safety, It represents the wave impedance ratio between the fish body medium and the swim bladder wall medium, Represents the fish body shape factor, 、 、 Respectively represent the swim bladder width factor, swim bladder wall thickness factor, and swim bladder critical tensile stress factor, 、 、 Respectively represent the swim bladder width index, swim bladder wall thickness index, and swim bladder critical tensile stress index, Indicates the length of the fish body; S32. Based on the critical wave pressure of fish safety and combined with the optimal attenuation model of underwater supercritical CO2 phase change pulse that varies with distance, the critical safety distance of fish of different body lengths under supercritical CO2 phase change pulse is obtained.
5. A supercritical CO2 underwater rock breaking device for collecting underwater pulse measured data as claimed in claim 1, characterized in that: include: The CO2 filling component is used to store liquid CO2 and control the filling temperature and pressure of the liquid CO2. When the filling temperature and pressure of the liquid CO2 reach the set thresholds, the liquid CO2 is in a supercritical state. Underwater fracturing assembly, used to stimulate the release of supercritical CO2 energy through blasting operation when liquid CO2 is in a supercritical state, generating supercritical CO2 phase change pulse peak pressure; The pulse monitoring component is used to collect real-time pulse transmission stress in water at different resistance line lengths and distances of the reef under the action of supercritical CO2 phase change pulse peak pressure, and generate underwater pulse measurement data.
6. The supercritical CO2 underwater rock breaking device according to claim 5, characterized in that: CO2 filling components include liquid CO2 gas cylinders, workbench, temperature and pressure control center, display, valves, booster pumps, and chillers; Liquid CO2 gas cylinder, used to store liquid CO2; Workbench, used to place various components, temperature and pressure control center; The temperature and pressure control center is used to control the filling temperature and pressure of liquid CO2 in the liquid CO2 storage cylinder by controlling the booster pump and chiller respectively; A display for displaying the filling temperature and pressure of liquid CO2 in the liquid CO2 storage cylinder; Valve, used to control the opening and closing of liquid CO2 gas cylinders; Booster pump, used to pressurize liquid CO2 storage cylinders; Chiller, used to regulate the temperature of liquid CO2 storage cylinders.
7. The supercritical CO2 underwater rock breaking device according to claim 6, characterized in that: The underwater fracturing components include test rock samples, test water tanks, fracturing tubes, protective devices, and detonators; Test water tank, used as a test site for supercritical CO2 phase change pulses and for placing test rock samples; Test rock samples are used to drill a central hole to create a fracturing hole, which is then used to place a fracturing tube; Fracturing tube, used to receive supercritical CO2; The detonator is used to detonate the supercritical CO2 in the fracturing tube and generate a supercritical CO2 phase change pulse peak pressure in the fracturing tube.
8. The device according to claim 7, characterized in that The protective devices include crack pipe limiters, iron chains, and cylindrical protective iron barrels; A fracture tube stopper, used to fix the position of the fracture tube; Cylindrical iron drum, used to wrap and fix the test rock sample; Iron chains are used to fix the position of fracturing tubes and test rock samples.
9. The device according to claim 8, characterized in that The pulse monitoring components include the Blast-PRO pulse tester and the TP-SJB-5M water pressure sensor; TP-SJB-5M water pressure sensor is used to collect underwater pulse transmission stress at different distances and lengths of different resistance lines of the reef when blasting occurs; The Blast-PRO pulse tester is used to display the underwater pulse transmission stress at different distances from the derived reef at different resistance line lengths.