An experimental device and evaluation method for controllable reconstruction of deep geothermal high temperature-energy-damage whole process

Abstract

This invention discloses an experimental apparatus and evaluation method for controllably reconstructing the entire process of deep-earth high-temperature-energy-damage, comprising: a stress loading subsystem, a dynamic thermo-fluid coupling circulation subsystem, an in-situ monitoring subsystem, and a control system. The control system is connected to the stress loading subsystem, the dynamic thermo-fluid coupling circulation subsystem, and the in-situ monitoring subsystem, respectively. The stress loading subsystem includes a true triaxial pressure vessel and multiple hydraulic loading heads that provide unequal stresses to the rock sample. The dynamic thermo-fluid coupling circulation subsystem includes a high-temperature storage tank, a low-temperature storage tank, and high-temperature circulation loops and low-temperature circulation loops respectively connected to the inlet of the true triaxial pressure vessel. The in-situ monitoring subsystem includes a waveguide rod acoustic emission monitoring group and a distributed optical fiber monitoring group. The dual-loop rapid switching design of this invention achieves, for the first time, millisecond-level response to large temperature difference fluid impact under true triaxial high-pressure conditions, reproducing the transient thermo-mechanical coupling process in engineering scenarios such as EGS water injection.

Description

Technical Field

[0001] This invention relates to an experimental apparatus and evaluation method for real-time monitoring and evaluation of the entire process of energy evolution in rock thermal fracture, and more particularly to an experimental apparatus and evaluation method for controllably reconstructing the entire process of deep-earth high-temperature-energy-damage. Background Technology

[0002] With the deepening development of deep Earth resources (such as enhanced geothermal systems (EGS), deep shale gas extraction, and deep-ground disposal of high-level radioactive waste), the thermo-mechanical-fluid coupling behavior of deep rock masses under conditions of "high geostress, high geothermal temperature, and high osmotic pressure" has become a research focus. Especially in EGS development, injecting cold water into high-temperature rock masses to induce fracture network propagation (thermal shock) is a core key technology. However, existing deep environment simulation test devices have the following limitations:

[0003] 1. Lack of dynamic thermal shock simulation capability: Most existing devices can only provide a constant high-temperature environment or an extremely slow heating rate. They cannot simulate the transient and drastic temperature gradient changes (thermal shock) caused by the sudden injection of cold fluid into high-temperature rock masses in engineering practice, resulting in experimental results that cannot truly reflect the fracturing mechanism of deep rocks.

[0004] 2. Difficulty in real-time monitoring at high temperatures: In high-temperature and high-pressure sealed cavities exceeding 200°C or even 300°C, traditional electronic sensors (such as acoustic emission probes and strain gauges) are prone to failure, making it difficult to capture real-time signals of the initiation and expansion of damage inside rocks. Often, only "black box" comparisons before and after the experiment can be performed.

[0005] 3. Lack of quantitative energy evaluation system: Existing evaluation methods are mostly based on qualitative observation of crack morphology or attenuation of a single mechanical parameter. There is a lack of evaluation methods that quantitatively correlate the input thermal energy with the energy released by rock fracture, making it difficult to accurately assess the efficiency of thermally induced cracking. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to propose an experimental device and evaluation method for controllably reconstructing the entire process of deep-earth high temperature-energy-damage, which can controllably reconstruct the deep-earth high temperature thermal shock process and overcome the bottleneck of high temperature monitoring, so as to achieve quantitative evaluation of the entire process of energy and damage.

[0007] Technical solution: The present invention includes a stress loading subsystem, a dynamic thermal-fluid coupled cycle subsystem, an in-situ monitoring subsystem, and a control system, wherein the control system is connected to the stress loading subsystem, the dynamic thermal-fluid coupled cycle subsystem, and the in-situ monitoring subsystem, respectively.

[0008] The stress loading subsystem includes a true triaxial pressure vessel for holding the rock sample and multiple hydraulic loading heads for providing unequal stress to the rock sample.

[0009] The dynamic heat-fluid coupled circulation subsystem includes a high-temperature storage tank, a low-temperature storage tank, and a high-temperature circulation loop and a low-temperature circulation loop respectively connected to the inlet of the true triaxial pressure vessel; a fast switching valve group is provided on the switching path of the high-temperature circulation loop and the low-temperature circulation loop. The fast switching valve group is used to simultaneously cut off the high-temperature circulation loop and connect the low-temperature circulation loop within a preset time threshold after receiving a thermal shock command, so that the cold fluid directly impacts the rock sample under high temperature and high ground stress.

[0010] The in-situ monitoring subsystem includes a waveguide rod acoustic emission monitoring group and a distributed optical fiber monitoring group; the waveguide rod acoustic emission monitoring group includes at least one waveguide rod, one end of which passes through the wall of the true triaxial pressure vessel and is in direct contact with the surface of the rock sample, and the other end is located in the ambient temperature zone outside the vessel and connected to an acoustic emission sensor; the distributed optical fiber monitoring group includes fiber gratings arranged along the surface or internal channels of the rock sample.

[0011] The high-temperature circulation loop includes a heater and a high-temperature circulation pump; the low-temperature circulation loop includes a refrigerator and a low-temperature circulation pump.

[0012] The input end of the quick-switching valve group is connected to the output end of the high-temperature circulating pump and the output end of the low-temperature circulating pump, respectively, and the output end of the quick-switching valve group is connected to the liquid inlet of the true triaxial pressure vessel.

[0013] The fiber optic grating is led out of the true triaxial pressure vessel and connected to the fiber optic demodulator.

[0014] The hydraulic loading heads respectively correspond to , , Three principal stress directions.

[0015] A method for evaluating the high-temperature-energy-damage process based on the aforementioned experimental setup for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process includes the following steps:

[0016] S1. The system controls multiple hydraulic loading heads to apply a preset true triaxial stress and activates a high-temperature circulation loop to heat the rock sample to the target temperature and maintain thermal equilibrium.

[0017] S2. The control system triggers the rapid switching valve group to cut off the high-temperature circulation loop and connect the low-temperature circulation loop, injecting cold fluid into the rock sample to form a thermal shock.

[0018] S3. During the thermal shock process, acoustic emission waveform signals are collected in real time through waveguide rods and acoustic emission sensors, while temperature gradient field data inside the rock sample is collected in real time through fiber optic gratings.

[0019] S4. Based on the data collected in step S3, calculate the thermal stress potential energy. Damage release energy and thermal cracking energy conversion rate :

[0020]

[0021]

[0022]

[0023] Where E is the elastic modulus of the rock; The coefficient of thermal expansion of the rock; The Poisson's ratio of the rock sample; For the temperature change of the rock sample; This represents the volume of the rock sample. The voltage signal for the k-th event; For the first The triggering time of an acoustic emission (AE) event; The length of the time window for each acoustic emission event.

[0024] The thermal stress potential energy is calculated based on the temperature gradient field measured by the high-temperature resistant fiber optic grating and the thermophysical parameters of the rock, and is generated by the thermal stress potential energy due to the temperature difference.

[0025] The above evaluation method also includes: comparing the calculated thermal fracturing energy conversion rate with a preset grading threshold, and outputting the thermal fracturing efficiency level of the rock sample under the current geostress and thermal shock conditions.

[0026] The thermal fracturing energy conversion rate is used to quantitatively evaluate the ability of a specific rock to convert thermal energy into fracturing damage under specific geostress and thermal shock conditions.

[0027] Beneficial effects: The present invention has the following advantages:

[0028] (1) Realistic reproduction of dynamic thermal shock: The innovative dual-loop fast switching design realizes the millisecond-level response of large temperature difference fluid shock in a true triaxial high-pressure environment for the first time, realistically reproducing the transient thermo-coupling process in engineering scenarios such as EGS water injection;

[0029] (2) Breakthrough in high temperature monitoring bottleneck: The high temperature sound signal is led out to the normal temperature range for measurement by using a waveguide rod, which effectively solves the problem that the existing acoustic emission sensor cannot work in an environment above 300℃, and realizes real-time auscultation of the damage process;

[0030] (3) Establishing new quantitative evaluation indicators: The thermal cracking energy conversion rate proposed in this invention breaks away from the traditional qualitative description and establishes a quantitative relationship between input thermal conditions and output damage energy, providing a direct scientific basis for the design and optimization of deep geothermal development. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the dynamic heat-fluid coupled cyclic subsystem of the present invention;

[0033] Figure 3 This is a schematic diagram of the layout of the high-temperature in-situ monitoring subsystem of the present invention;

[0034] Figure 4 This is a flowchart of the present invention. Detailed Implementation

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] Example 1

[0037] like Figure 1 As shown, the experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process in this embodiment achieves dynamic thermal shock through an innovative dual-loop temperature control system, utilizes high-temperature resistant composite monitoring technology for real-time data capture, and establishes an energy-based quantitative evaluation system. It includes: a stress loading subsystem, a dynamic heat-flow coupled cycle subsystem, a high-temperature resistant in-situ monitoring subsystem, and a control system. The control system is connected to the stress loading subsystem, the dynamic heat-flow coupled cycle subsystem, and the high-temperature resistant in-situ monitoring subsystem, respectively.

[0038] The stress loading subsystem includes a true triaxial pressure vessel 1 for housing the rock sample 6, and three hydraulic loading heads for providing unequal stresses to the rock sample 6: a first hydraulic loading head 2, a second hydraulic loading head 3, and a third hydraulic loading head 4. The true triaxial pressure vessel 1 is connected to the base 23 by bolts 5; the first hydraulic loading head 2, the second hydraulic loading head 3, and the third hydraulic loading head 4 correspond to... , , Three principal stress directions, and > > It is used to apply true triaxial geostress to simulate a deep-earth environment. Rock specimen 6 is a standard granite with uniform texture and no obvious natural cracks, which is processed into a cubic rock specimen with a size of 100mm * 100mm * 100mm.

[0039] like Figure 2As shown, the dynamic heat-fluid coupled circulation subsystem is used to achieve controllable dynamic changes in the temperature field within the reactor. It includes a high-temperature storage tank 16, a heater 17, a high-temperature circulation pump 18, a fast-switching valve assembly 19, a low-temperature storage tank 20, a refrigerator 21, and a low-temperature circulation pump 22. The high-temperature storage tank 16 is connected to the heater 17, which is connected to the high-temperature circulation pump 18. The high-temperature circulation pump 18 is connected to the fast-switching valve assembly 19, forming a high-temperature circulation loop. The low-temperature storage tank 20 is connected to the refrigerator 21, which is connected to the low-temperature circulation pump 22. The low-temperature circulation pump 22 is connected to the fast-switching valve assembly 19, forming a low-temperature circulation loop. The input end of the quick-switching valve group 19 is connected to the output end of the high-temperature circulating pump 18 and the output end of the low-temperature circulating pump 22 respectively. The output end of the quick-switching valve group 19 is connected to the liquid inlet 8 of the true triaxial pressure vessel 1. The quick-switching valve group 19 is used to cut off the high-temperature circulation loop and connect the low-temperature circulation loop within a few seconds after receiving the thermal shock command, so that the cold fluid directly impacts the rock sample 6 under high temperature and high ground stress, thereby realizing a controllable thermal shock process.

[0040] The high-temperature storage tank 16 stores a circulating high-temperature heat transfer medium, which is either high-temperature silicone oil or thermally conductive molten salt. The heater 17 heats the circulating high-temperature heat transfer medium to the target temperature. The high-temperature circulating pump 18 pumps the high-temperature heat transfer medium into the true triaxial pressure vessel 1 through the inlet 8 of the true triaxial pressure vessel 1 via the quick-switching valve group 19. The low-temperature storage tank 20 stores low-temperature condensate, which is water. After the refrigerator 21 controls the condensate temperature to the target temperature, the low-temperature circulating pump 22 pumps the condensate into the true triaxial pressure vessel 1 through the inlet 8 of the true triaxial pressure vessel 1 via the quick-switching valve group 19. The outlet 7 of the true triaxial pressure vessel 1 is connected to the return pipeline.

[0041] like Figure 3 As shown, the high-temperature resistant in-situ monitoring subsystem is used to overcome the high-temperature environment and capture damage signals. It includes a waveguide rod acoustic emission monitoring group and a distributed optical fiber monitoring group. The waveguide rod acoustic emission monitoring group includes a novel high-temperature resistant ceramic waveguide rod 10, a high-sensitivity acoustic emission sensor 11, and an acoustic emission data acquisition instrument 12. One end of the ceramic waveguide rod 10 passes through the wall of the true triaxial pressure vessel 1 and is sealed to be in close contact with the rock sample 6 to receive the fracture signal. The other end is located in the room temperature zone outside the vessel and is connected to the acoustic emission sensor 11. The acoustic emission sensor 11 is connected to the acoustic emission data acquisition instrument 12.

[0042] The distributed optical fiber monitoring group includes a high-temperature resistant fiber optic grating 13 and an optical fiber demodulator 14. The high-temperature resistant fiber optic grating 13 is arranged along the surface of the rock sample 6 or through pre-drilled holes, and its two ends are led out from the true triaxial pressure vessel 1 and connected to the optical fiber demodulator 14 to monitor the changes in temperature gradient field and micro-strain field along the optical fiber path in real time.

[0043] The control system includes a measurement and control computer 15, which is connected to a true triaxial stress loading subsystem, a dynamic heat-fluid coupling cycle subsystem, and a high-temperature in-situ monitoring subsystem. It is used to coordinate and control stress loading and heat fluid switching, and to synchronously acquire acoustic emission signals, fiber optic signals, temperature, pressure, and flow data.

[0044] Example 2

[0045] like Figure 4 As shown in this embodiment, the evaluation method for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process includes the following steps:

[0046] Step S1: Deep Earth Environment Initialization and Reconstruction. Rock samples are loaded into the reactor, a preset true triaxial stress is applied, the high-temperature sustaining circuit is activated, and the samples are slowly heated to the target deep earth temperature T. target And maintain thermal equilibrium and record the baseline state.

[0047] Step S2: Controllable thermal shock application. The control system triggers the rapid thermal switching module to cut off the high-temperature circuit, with the injection temperature at T. cold The cold fluid. By adjusting the flow rate and temperature difference ΔT = T of the cold fluid. target - T cold To control the intensity and rate of thermal shock.

[0048] Step S3: Synchronous data acquisition throughout the entire process. During the thermal shock process, a novel high-temperature resistant ceramic waveguide is used to capture high-frequency elastic wave signals generated by the thermal fracture of the rock in real time; a high-temperature resistant fiber optic grating (FBG) is used to record the transient temperature field changes and local thermal strain on the sample surface.

[0049] Step S4: Quantitative assessment of energy-damage, including the following;

[0050] S41. Calculate the thermal stress potential energy E thermal Based on the temperature gradient field and rock thermophysical parameters measured by high-temperature resistant fiber grating (FBG), the thermal stress potential energy generated by the temperature difference is calculated.

[0051]

[0052] in, E represents the thermal stress potential energy; E is the rock elastic modulus. The coefficient of thermal expansion of the rock; The Poisson's ratio of the rock sample; For the temperature change of the rock sample; The volume is the rock sample volume.

[0053] S42. Calculate the damage release energy E acousticThe collected acoustic emission waveform signals are processed to calculate the cumulative acoustic emission energy or the total number of ring counts during the entire thermal shock process, which characterizes the total mechanical energy released by the damage.

[0054]

[0055] in Energy released due to damage; The voltage signal for the k-th event needs to be converted into energy and corrected using a high-sensitivity acoustic emission sensor.

[0056] S43. Constructing an evaluation index—thermal cracking energy conversion rate This index is used to quantitatively evaluate the ability of a specific rock to convert thermal energy into fracture damage under specific geostress and thermal shock conditions.

[0057]

[0058] in, For damage release energy, This is the potential energy of thermal stress.

[0059] Example 3

[0060] This embodiment aims to use the device of the present invention to simulate the dynamic thermal shock damage process caused by the sudden injection of room temperature water at 20°C into a high-temperature granite mass at approximately 250°C in a deep (approximately 2000-3000 meters) high geostress environment, and to quantitatively evaluate the efficiency of its thermal energy conversion into fracture energy.

[0061] In this embodiment, standard granite with uniform texture and no obvious natural fissures was selected and processed into cubic rock samples with dimensions of 100mm * 100mm * 100mm. A 3mm diameter hole was pre-drilled on the central axis of the sample, and a high-temperature resistant (withstanding 350℃) distributed fiber optic sensor (integrated FBG grating array) was implanted into the hole and encapsulated with high-temperature resistant thermally conductive adhesive for measuring the internal temperature and strain fields of the sample. The area on the side of the sample that contacts the novel high-temperature resistant waveguide rod was ground smooth to ensure good acoustic coupling.

[0062] The prepared rock sample is placed into the core cavity of the true triaxial pressure vessel, ensuring tight contact between each hydraulic loading head and all surfaces of the sample. Multiple specially designed high-temperature resistant ceramic waveguide rods are passed through the sealed interfaces on the side wall of the vessel, with their inner ends pressed against the surface of the rock sample. A high-sensitivity acoustic emission sensor is coupled to the ends of the waveguide rods extending outside the vessel, and the sensor is connected to an acoustic emission data acquisition instrument. An embedded optical fiber is led out of the vessel and connected to an optical fiber demodulator. The fluid inlet and outlet of the true triaxial pressure vessel are connected to a quick-switching valve module and a reflux pipeline, respectively.

[0063] In the red high-temperature circuit, the high-temperature storage tank is filled with high-temperature resistant heat-conducting oil (such as methyl silicone oil) and connected to the heater and high-temperature pump; in the blue low-temperature circuit, the low-temperature storage tank is filled with distilled water and connected to the refrigerator and low-temperature pump; all pumps, valves, heating / cooling equipment, and data acquisition instruments are connected to the control computer for centralized control and time synchronization. The entire experiment is conducted strictly according to the control computer's coordination. Figure 4 Follow the steps shown.

[0064] Step S1: Deep Earth Environment Initialization and Reconstruction

[0065] 1. Applying true triaxial stress: Triaxial stress is simultaneously applied at a rate of 0.5 MPa / min using three hydraulic loading heads until the preset deep geostress state is reached: maximum principal stress. = 60MPa (simulated vertical ground stress), intermediate principal stress = 40MPa, minimum principal stress = 20 MPa, keep the stress constant.

[0066] 2. Heat to the target high temperature and allow for thermal equilibrium:

[0067] The control system activates the high-temperature circuit via a rapid switching valve module, starting the high-temperature pump and heater. The target temperature is set to 250℃. High-temperature heat transfer oil circulates within the circuit and the reactor to heat the sample. To prevent thermal damage during heating, the heating rate is controlled to not exceed 2℃ / min. The internal temperature of the rock sample is monitored in real time using a fiber optic demodulator. When the temperature at each measuring point monitored by the fiber optic cable stabilizes at 250℃±2℃ and remains stable for at least 2 hours, thermal equilibrium is considered to have been reached, and this process is recorded as the baseline state.

[0068] Step S2: Applying controlled thermal shock

[0069] 1. Prepare the cold fluid: Start the refrigeration unit in advance to maintain the water temperature in the cryogenic storage tank at 20°C. Start the cryogenic pump to pre-circulate the cold water in the cryogenic circuit and set the injection flow rate to 200 ml / min.

[0070] 2. Perform thermal shock switching:

[0071] The control computer issues a "thermal shock start" command. The rapid switching valve module completes its action within one second: simultaneously cutting off the flow of high-temperature heat transfer oil into the reactor body and connecting the low-temperature circuit, allowing 20°C cold water to be instantly injected into the pressure vessel cavity filled with the 250°C high-temperature rock sample at a set flow rate. At this moment, the surface and internal pores of the rock sample experience a drastic temperature difference, creating a strong cold shock. The cold water injection continues for approximately 30 minutes, until fiber optic monitoring indicates a significant drop in sample temperature that gradually levels off.

[0072] Step S3: Synchronous Data Acquisition Throughout the Process

[0073] Throughout the execution of step S2, control and data acquisition maintain high-frequency synchronization:

[0074] Acoustic emission (AE) signal: The acoustic emission data acquisition instrument continuously records the high-frequency elastic wave signal generated by the thermal fracturing of rock through the waveguide rod, and records the number of impacts (Hits), ring count, energy and three-dimensional positioning information to capture the dynamic process of microcrack initiation and propagation.

[0075] Temperature field / strain field (fiber optic): The fiber optic demodulator records the wavelength drift information fed back by the distributed fiber optic sensor at a frequency of up to 100 Hz, demodulating the changes in the transient temperature gradient field inside the sample during thermal shock, as well as the accompanying thermal contraction strain field.

[0076] Step S4: Energy-damage quantification and assessment

[0077] After the experiment, the collected data were processed offline and quantitatively evaluated.

[0078] 1. Thermal stress potential energy (E) thermal Based on the spatiotemporal temperature field T(x,y,z,t) data inside the rock measured by optical fiber, combined with the thermophysical parameters such as the thermal expansion coefficient and elastic modulus of granite, the total thermal stress potential energy generated inside the rock due to the rapid temperature difference during the thermal shock process is calculated by integral using the thermoelastic mechanics theory formula, and used as the input total energy driving term.

[0079] The formula for calculating the thermal stress potential energy of an optical fiber sensor is:

[0080]

[0081] in E represents the thermal stress potential energy; E is the rock elastic modulus. The coefficient of thermal expansion of the rock; The Poisson's ratio of the rock sample; For the temperature change of the rock sample; The volume is the rock sample volume.

[0082] The calculated thermal stress potential energy in this embodiment is 5 * 10^5 J.

[0083] 2. Calculate the damage release energy (E) acoustic The absolute energy of all valid acoustic emission events collected by the acoustic emission device in step S3 is integrated over time to obtain the cumulative acoustic emission energy during the entire thermal shock process. This energy represents the total mechanical energy released by the rock in overcoming internal cohesion to generate new cracks.

[0084] The formula for calculating the damage release energy of the acoustic emission device in this embodiment is:

[0085]

[0086] in Energy released due to damage; The voltage signal for the k-th event needs to be converted into energy (corrected using a high-sensitivity acoustic emission sensor).

[0087] The damage release energy calculated in this embodiment is 2.5 * 10^3 J.

[0088] The formula for calculating the energy conversion rate of thermal cracking is:

[0089]

[0090] in For damage release energy, This is the potential energy of thermal stress.

[0091] The thermal cracking energy conversion rate calculated in this embodiment is η. TC = 0.5%.

[0092] 4. Construct the evaluation index thermal cracking energy conversion rate as shown in Table 1. .

[0093] Table 1 Evaluation Indicators for Thermal Cracking Energy Conversion Rate

[0094]

[0095] Among them, "extremely low" indicates that the rock's thermodynamic properties are very stable, and thermal shock is essentially ineffective. With... As the value gradually increases, the effect of thermal shock on rock fracture becomes increasingly significant.

[0096] In this embodiment, the thermal cracking energy conversion rate η of the granite sample is... TC It is 0.5%. Based on the thermal cracking energy conversion rate... The evaluation indicators show that the thermal fracturing energy conversion rate of this granite sample is relatively low. The rock has a certain thermal fracturing conversion ability, but it is generally in a stable state, which is consistent with the typical performance of most dense rocks such as granites.

Claims

1. An experimental apparatus for controllably reconstructing the entire process of deep-earth high-temperature-energy-damage, characterized in that, It includes a stress loading subsystem, a dynamic thermal-fluid coupled cycle subsystem, an in-situ monitoring subsystem, and a control system, wherein the control system is connected to the stress loading subsystem, the dynamic thermal-fluid coupled cycle subsystem, and the in-situ monitoring subsystem, respectively. The stress loading subsystem includes a true triaxial pressure vessel (1) for placing the rock sample (6) and multiple hydraulic loading heads for providing unequal stress to the rock sample (6). The dynamic heat-fluid coupled circulation subsystem includes a high-temperature storage tank (16), a low-temperature storage tank (20), and a high-temperature circulation loop and a low-temperature circulation loop respectively connected to the inlet (8) of the true triaxial pressure vessel (1); a fast switching valve group (19) is provided on the switching path of the high-temperature circulation loop and the low-temperature circulation loop. The fast switching valve group (19) is used to simultaneously cut off the high-temperature circulation loop and connect the low-temperature circulation loop within a preset time threshold after receiving the thermal shock command, so that the cold fluid directly impacts the rock sample (6) under high temperature and high ground stress. The in-situ monitoring subsystem includes a waveguide rod acoustic emission monitoring group and a distributed optical fiber monitoring group; the waveguide rod acoustic emission monitoring group includes at least one waveguide rod, one end of which passes through the wall of the true triaxial pressure vessel (1) and is in direct contact with the surface of the rock sample (6), and the other end is located in the ambient temperature zone outside the vessel and connected to the acoustic emission sensor (11); the distributed optical fiber monitoring group includes fiber gratings arranged along the surface or internal channels of the rock sample (6).

2. The experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 1, characterized in that, The high-temperature circulation loop includes a heater (17) and a high-temperature circulation pump (18).

3. The experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 2, characterized in that, The cryogenic circulation loop includes a refrigerator (21) and a cryogenic circulation pump (22).

4. The experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 3, characterized in that, The input end of the quick-switching valve group (19) is connected to the output end of the high-temperature circulating pump (18) and the output end of the low-temperature circulating pump (22), respectively, and the output end of the quick-switching valve group (19) is connected to the liquid inlet (8) of the true triaxial pressure vessel (1).

5. The experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 1, characterized in that, The fiber optic grating is led out from the true triaxial pressure vessel (1) and connected to the fiber optic demodulator (14).

6. The experimental apparatus for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 1, characterized in that, The hydraulic loading heads respectively correspond to , , Three principal stress directions.

7. A method for evaluating the high-temperature-energy-damage process based on the experimental apparatus for controllable reconstruction of the deep-earth high-temperature-energy-damage process according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. The system controls multiple hydraulic loading heads to apply a preset true triaxial stress and activates a high-temperature circulation loop to heat the rock sample to the target temperature and maintain thermal equilibrium. S2. The control system triggers the rapid switching valve group to cut off the high-temperature circulation loop and connect the low-temperature circulation loop, injecting cold fluid into the rock sample to form a thermal shock. S3. During the thermal shock process, acoustic emission waveform signals are collected in real time through waveguide rods and acoustic emission sensors, while temperature gradient field data inside the rock sample is collected in real time through fiber optic gratings. S4. Based on the data collected in step S3, calculate the thermal stress potential energy. Damage release energy and thermal cracking energy conversion rate : Where E is the elastic modulus of the rock; The coefficient of thermal expansion of the rock; The Poisson's ratio of the rock sample; For the temperature change of the rock sample; This represents the volume of the rock sample. The voltage signal for the k-th event; For the first The triggering time of an acoustic emission event; The length of the time window for each acoustic emission event.

8. The evaluation method for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 7, characterized in that, The thermal stress potential energy is calculated based on the temperature gradient field measured by fiber optic grating and the thermophysical parameters of the rock, and is generated by the thermal stress potential energy due to the temperature difference.

9. The evaluation method for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 7, characterized in that, Also includes: The calculated thermal fracturing energy conversion rate is compared with a preset grading threshold to output the thermal fracturing efficiency level of the rock sample under the current geostress and thermal shock conditions.

10. The evaluation method for controllable reconstruction of the entire deep-earth high-temperature-energy-damage process according to claim 9, characterized in that, The thermal fracturing energy conversion rate is used to quantitatively evaluate the ability of a specific rock to convert thermal energy into fracturing damage under specific geostress and thermal shock conditions.

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