An underground high-pressure gas storage surrounding rock cyclic gas load fatigue regulation method and system

Abstract

The application discloses a kind of underground high-pressure gas storage surrounding rock cyclic gas load fatigue control method and system. The inner ring monitoring hole and the outer ring monitoring hole of near field are arranged radially corresponding to the main test hole, and multiple radial monitoring partitions are formed;In the cyclic gas load loading process, the inner ring acoustic emission wake-up pressure and the outer ring acoustic emission wake-up pressure of each partition are extracted, the outer ring dynamic Felicity ratio and the wake-up pressure interval contraction index are determined, and the outer ring fatigue invasion index is determined in combination with the stress of outer ring surrounding rock and pore gas pressure anomaly.When it is determined that one or more radial monitoring partitions occur outer ring fatigue invasion, determine the dangerous partition, and adjust the subsequent cyclic pressure upper limit, pressure increasing rate, pressure maintaining time and low pressure recovery time in stages, if necessary, terminate loading and safely depressurize.The application can identify the risk of fatigue damage spreading from near field to outer ring, and realize self-adaptive control of cyclic loading system.

Description

Technical Field

[0001] This invention belongs to the field of intelligent monitoring and early warning, high-pressure gas cyclic loading test and fatigue damage control technology for underground engineering, specifically a method and system for fatigue control of circulating gas load in the surrounding rock of an underground high-pressure gas storage facility. Background Technology

[0002] Underground compressed air storage facilities, underground hydrogen storage facilities, and similar high-pressure gas storage projects typically undergo repeated charging and discharging processes during operation. Under the pressure of circulating gas, the surrounding rock may experience gradual expansion of fractures, evolution of seepage channels, and accumulation of localized fatigue damage. Unlike single-stage pressure-driven rupture, the danger signals under cyclic loading often manifest as premature acoustic emission, abnormal stress response in the outer surrounding rock, and enhanced pore pressure fluctuations.

[0003] Existing cyclic loading tests are mostly performed according to fixed pressure upper limits, fixed holding times, and fixed number of cycles, lacking the ability to identify whether fatigue damage has spread from the near field of the main test port to the outer control area. Simply stopping the machine based on the number of cycles or the single-point acoustic emission threshold makes it difficult to distinguish between permissible fatigue response in the near field and dangerous intrusion in the outer circle.

[0004] Therefore, it is necessary to propose a cyclic airborne fatigue control method based on the acoustic emission wake-up pressure of the inner and outer rings, the dynamic Feliceti ratio of the outer ring, the surrounding rock stress of the outer ring, and the pore air pressure of the outer ring, so as to dynamically identify the fatigue intrusion of the outer ring and adjust the subsequent cyclic pressure regime. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regulating fatigue in the surrounding rock of underground high-pressure gas storage under circulating air load, which solves the problems of difficulty in identifying fatigue damage expansion, lack of correlation between the acoustic emission responses of the inner and outer rings, lack of adaptive adjustment of the circulating pressure regime, and difficulty in timely determination of fatigue intrusion in the outer ring control area in existing circulating air load tests.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for controlling the fatigue of surrounding rock under circulating gas load in an underground high-pressure gas storage facility is implemented using a high-pressure gas circulating loading system and a surrounding rock array monitoring system. The high-pressure gas circulating loading system includes a high-pressure radial loading unit installed in the main test borehole, a high-pressure gas source, an inlet pressure regulating valve group, a pressure holding valve group, a pressure relief valve group, a pressure sensor, and a circulating loading control unit. The surrounding rock array monitoring system includes a near-field inner ring monitoring borehole array and a far-field outer ring monitoring borehole array. An inner ring acoustic emission sensor is installed in the near-field inner ring monitoring borehole array, while an outer ring acoustic emission sensor, an outer ring surrounding rock stress sensor, and an outer ring pore pressure sensor are installed in the far-field outer ring monitoring borehole array.

[0008] This invention uses radial monitoring zones as the basic discrimination unit. Each radial monitoring zone includes a near-field inner ring monitoring aperture and a far-field outer ring monitoring aperture located within the same radial monitoring profile. .

[0009] Before the actual cyclic loading, the system sets a lower limit for the cyclic pressure. Upper limit of circulating pressure Boost rate Holding time Voltage drop rate Low pressure recovery time The number of cycles was then determined. Subsequently, a baseline cycle loading was performed to obtain the acoustic emission background of each radial monitoring zone, the acoustic emission wake-up pressure difference baseline between the inner and outer rings, the dynamic Feliceti ratio stability range of the outer ring, the stress baseline of the surrounding rock in the outer ring, and the pore gas pressure baseline of the outer ring.

[0010] In the In the formal cyclic boost phase, the system uses a sliding time window as the discrimination unit to extract the weighted inner-circle acoustic emission response index. and outer ring acoustic emission response index When the acoustic emission response index exceeds the background threshold for multiple consecutive time windows for the first time, the corresponding pressure in the main test port is recorded as the acoustic emission wake-up pressure. The inner ring acoustic emission wake-up pressure is... The outer ring acoustic emission wake-up pressure is .

[0011] The system calculates the dynamic Felicity ratio of the outer ring:

[0012] When acoustic emission from the outer ring occurs earlier than the upper limit of the previous cycle pressure, it indicates that the outer ring control region responds to the circulating air load earlier. reduce.

[0013] The system also calculates the acoustic emission wake-up pressure difference between the inner and outer rings:

[0014] And calculate the awakening pressure interval contraction index:

[0015] When cyclic fatigue damage is mainly confined to the near-field region of the main test hole, the acoustic emission wake-up pressure of the outer ring is usually significantly higher than that of the inner ring. Larger; as fatigue damage progresses towards the outer control region, outer acoustic emission occurs earlier. Shrink Increase.

[0016] Furthermore, the system calculates the cyclic anomaly of stress in the outer surrounding rock. and abnormal amount of air pressure circulation in the outer ring pores And construct the outer ring fatigue intrusion index:

[0017] The first term characterizes the degree to which the acoustic emission of the outer ring advances relative to the upper limit of the pressure of the previous cycle; the second term characterizes the continued downward trend of the dynamic ferriti ratio of the outer ring; the third term characterizes the degree of contraction of the acoustic emission awakening pressure difference between the inner and outer rings; the fourth term characterizes the anomaly of the surrounding rock stress in the outer ring; and the fifth term characterizes the anomaly of the pore gas pressure in the outer ring.

[0018] When the outer ring fatigue intrusion index exceeds the warning threshold and the outer ring dynamic Feliceti ratio remains below the lower limit of the stable range, the system determines that outer ring fatigue intrusion has occurred in that radial monitoring zone. When outer ring fatigue intrusion occurs simultaneously in multiple radial monitoring zones, the radial monitoring zone with the largest outer ring fatigue intrusion index is selected as the dangerous zone.

[0019] The cyclic loading control unit adjusts the subsequent cyclic loading regime based on the outer ring fatigue intrusion index of the hazardous zone. This includes lowering the upper limit of the next cycle pressure, reducing the pressurization rate, shortening the holding time, increasing the low-pressure recovery time, or terminating the cyclic loading. The upper limit of the next cycle pressure can be adjusted using the following formula:

[0020] in, The fatigue intrusion intensity is segmented according to normalization, so that the higher the degree of fatigue intrusion, the more significant the decrease in the upper limit of pressure in the next cycle.

[0021] Compared with the prior art, the present invention has the following beneficial effects.

[0022] First, the present invention uses radial monitoring zones as basic units to identify whether fatigue damage under cyclic air load develops from the near field to the outer control area.

[0023] Second, this invention combines the acoustic emission wake-up pressure difference between the inner and outer rings, the dynamic Feliceti ratio of the outer ring, and the cyclic historical response to identify the early wake-up of acoustic emission and its spatial expansion trend.

[0024] Third, this invention combines the decrease in the dynamic Felicity ratio of the outer ring, the contraction of the interval between the inner and outer ring awakening pressures, the abnormal stress of the outer ring surrounding rock, and the abnormal pore gas pressure of the outer ring into the outer ring fatigue intrusion index, thereby improving the reliability of fatigue intrusion identification.

[0025] Fourth, the present invention adjusts the subsequent cyclic pressure regime in stages according to the degree of fatigue intrusion in the dangerous zone, so as to avoid the continuous accumulation of fatigue damage caused by a fixed cyclic regime. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort. Wherein: Figure 1 This is a flowchart illustrating the overall process of the method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to the present invention. Figure 2 This is a schematic diagram of the surrounding rock array monitoring layout and system composition of the present invention, wherein... Figure 2 (a) is a schematic diagram of the planar arrangement of the main test aperture, the near-field inner ring monitoring aperture array, and the far-field outer ring monitoring aperture array. Figure 2 (b) is a schematic diagram of the system composition and connection relationships; Figure 3 This is a schematic diagram of the circulating air-carrying pressure system of the present invention; Figure 4 This is a schematic diagram of the inner and outer ring acoustic emission wake-up pressure extraction, in which... Figure 4 (a) is a schematic diagram of inner ring acoustic emission wake-up pressure extraction. Figure 4 (b) is a schematic diagram of outer ring acoustic emission wake-up pressure extraction; Figure 5 This is a schematic diagram of the outer ring dynamic Felicity ratio and the contraction of the awakening pressure interval, in which... Figure 5 (a) shows a schematic diagram of the dynamic changes in the Felicity ratio of the outer ring. Figure 5 (b) is a schematic diagram showing the change in the acoustic emission wake-up pressure difference between the inner and outer rings; Figure 6 This is a schematic diagram illustrating the calculation of the outer ring fatigue intrusion index and the selection of hazardous zones in this invention. Figure 7 This is a schematic diagram illustrating the adaptive adjustment of the subsequent cyclical pressure system, in which... Figure 7 (a) is a schematic diagram illustrating the graded determination of the pressure upper limit attenuation coefficient. Figure 7 (b) is a schematic diagram of subsequent cycle pressure adjustment.

[0027] Explanation of reference numerals in the attached figures: 1. Main test hole; 2. High-pressure radial loading unit; 3. Near-field inner ring monitoring hole; 4. Far-field outer ring monitoring hole; 5. Inner ring acoustic emission sensor; 6. Outer ring acoustic emission sensor; 7. Outer ring surrounding rock stress sensor; 8. Outer ring pore air pressure sensor; 9. High-pressure air source; 10. Inlet pressure regulating valve group; 11. Pressure holding valve group; 12. Pressure relief valve group; 13. Pressure sensor; 14. Acoustic emission acquisition module; 15. Outer ring low-frequency acquisition module; 16. Cyclic loading control unit; 17. Industrial control host; 18. First radial monitoring zone; 19. Second radial monitoring zone; 20. Third radial monitoring zone; 21. Fourth radial monitoring zone. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. The embodiments are used to illustrate the implementation of the present invention and are not intended to limit the scope of protection of the present invention; without departing from the technical concept of the present invention, the number of monitoring holes, sensor type, circulating pressure regime, threshold coefficient, and control parameters can all be adjusted according to the on-site rock mass conditions.

[0029] Specifically, refer to Figure 2 This embodiment provides a circulating gas load fatigue control system for the surrounding rock of an underground high-pressure gas storage facility. The system includes a high-pressure gas circulation loading system and a surrounding rock array monitoring system.

[0030] like Figure 2 As shown in (b), a main test hole 1 is drilled in the rock mass to be tested, and a high-pressure radial loading unit 2 is arranged inside the main test hole 1. The high-pressure radial loading unit 2 is connected to a high-pressure air source 9 through a high-pressure pipeline. An inlet pressure regulating valve group 10, a pressure holding valve group 11, a pressure relief valve group 12, and a pressure sensor 13 are installed on the high-pressure pipeline. The inlet pressure regulating valve group 10 is used to control the pressure increase rate and the air intake, the pressure holding valve group 11 is used to maintain pressure stability, the pressure relief valve group 12 is used to control the pressure decrease rate, and the pressure sensor 13 is used to collect the loading pressure inside the main test hole 1.

[0031] A near-field inner ring monitoring hole 3 and a far-field outer ring monitoring hole 4 are set around the main test hole 1. An inner ring acoustic emission sensor 5 is installed in the near-field inner ring monitoring hole 3, and an outer ring acoustic emission sensor 6, an outer ring surrounding rock stress sensor 7, and an outer ring pore air pressure sensor 8 are installed in the far-field outer ring monitoring hole 4. The inner ring acoustic emission sensor 5 and the outer ring acoustic emission sensor 6 are connected to the acoustic emission acquisition module 14; the outer ring surrounding rock stress sensor 7 and the outer ring pore air pressure sensor 8 are connected to the outer ring low-frequency acquisition module 15; both the acoustic emission acquisition module 14 and the outer ring low-frequency acquisition module 15 are connected to the cyclic loading control unit 16.

[0032] The radial distance between the near-field inner ring monitoring aperture array and the center of the main test aperture is The radial distance between the far-field outer ring monitoring aperture array and the center of the main test aperture is ,and This establishes a radial hierarchical monitoring relationship between the near-field inner circle and the far-field outer circle.

[0033] Pressure sensor 13, acoustic emission acquisition module 14, and outer ring low-frequency acquisition module 15 are respectively connected to cyclic loading control unit 16; cyclic loading control unit 16 is respectively connected to intake pressure regulating valve group 10, pressure holding valve group 11, and pressure relief valve group 12, and is used to control the upper limit of cyclic pressure, pressure increase rate, pressure holding time, pressure decrease rate, and low pressure recovery time according to the acquired loading pressure, inner and outer ring acoustic emission response, outer ring surrounding rock stress response, and outer ring pore air pressure response.

[0034] like Figure 2 As shown in (a), in a preferred embodiment, four near-field inner ring monitoring holes 3 and four far-field outer ring monitoring holes 4 are provided. The four near-field inner ring monitoring holes 3 and the four far-field outer ring monitoring holes 4 are arranged in a cross shape, a ring shape with equal angles, approximately equal angles, or non-equal angles adjusted according to the initial geostress direction, dominant joint fracture orientation, bedding direction, and weak structural surface direction of the test area along the circumference of the main test hole 1.

[0035] A near-field inner ring monitoring hole 3 and a far-field outer ring monitoring hole 4 located within the same design azimuth angle or the same radial monitoring profile constitute a radial monitoring zone. When the azimuth angle deviation between the near-field inner ring monitoring hole 3 and the far-field outer ring monitoring hole 4 does not exceed the preset allowable deviation, they are still considered to be located within the same radial monitoring profile. The four sets of corresponding monitoring holes form the first radial monitoring zone 18, the second radial monitoring zone 19, the third radial monitoring zone 20, and the fourth radial monitoring zone 21, respectively, to identify whether the cyclic airborne fatigue response in the corresponding direction develops from the near-field inner ring region to the far-field outer ring control region.

[0036] Furthermore, refer to Figure 3 Based on the above system, cyclic air loading is implemented in each radial monitoring zone, and each radial monitoring zone is used as the basic unit for comparing the inner and outer ring responses and determining fatigue intrusion.

[0037] The cyclic loading control unit 16 sets the cyclic air loading regime. One cycle includes a pressurization phase, a pressure holding phase, a pressure reduction phase, and a low-pressure recovery phase. The lower limit of pressure for each cycle is The upper limit of pressure is The boost rate is The pressure holding time is The rate of voltage reduction is The low-pressure recovery time is In the initial formal loop, The design cyclic pressure limit can be set; when fatigue intrusion of the outer ring is subsequently detected, the cyclic loading control unit 16 adaptively adjusts the subsequent cyclic pressure regime.

[0038] Furthermore, refer to Figure 3 Before the formal cyclic loading, a baseline cyclic loading phase is performed. This baseline cyclic phase is used to obtain the acoustic emission, outer ring surrounding rock stress, and outer ring pore gas pressure background response of each radial monitoring zone under safe cyclic conditions, and includes no less than... A loop, in which The upper limit of the pressure in the reference cycle section is lower than the pressure at which fatigue damage is expected to develop rapidly, but higher than the low-pressure preload pressure. Within the reference cycle section, the system collects the inner ring acoustic emission response, outer ring acoustic emission response, outer ring surrounding rock stress response, and outer ring pore gas pressure response of each radial monitoring zone, obtaining the inner ring acoustic emission background mean and standard deviation, the outer ring acoustic emission background mean and standard deviation, and the outer ring surrounding rock stress baseline. outer ring pore pressure baseline Standard deviation of stress fluctuation in the outer surrounding rock and the standard deviation of outer pore pressure fluctuation ; Based on the data collected from the baseline cycle section, the baseline for acoustic emission wake-up pressure difference between the inner and outer rings, the stable range of the outer ring dynamic Felicetic ratio, the reference stress, the reference pore pressure, and the warning threshold for the outer ring fatigue intrusion index are further determined for each radial monitoring zone. These criteria are used for subsequent acoustic emission wake-up identification, dynamic Felicetic ratio anomaly judgment, multi-source anomaly normalization, and outer ring fatigue intrusion judgment, respectively.

[0039] Furthermore, refer to Figure 4 Before the pressurization phase of each formal cycle, the inner and outer acoustic emission response indices of each radial monitoring zone in the low-pressure background section are obtained to determine the inner and outer background thresholds of this cycle.

[0040] In the In each cyclic boost phase, the system assigns event weights to acoustic emission events. When an acoustic emission event is determined to be an acoustic emission event due to rock mass fracturing, When an acoustic emission event is determined to be gas flow noise, gas jet noise, pipeline vibration noise, or electromagnetic interference noise, When an acoustic emission event is determined to be a suspected mixed event, ; The inner ring acoustic emission response index and outer ring acoustic emission response index To be based on the event weight The weighted acoustic emission event rate obtained after removing or downweighting acoustic emission events, the weighted acoustic emission energy release rate after propagation attenuation correction, or a combination of the two indicators; By assigning weights to the aforementioned events, acoustic emission events related to rock mass fracture are retained in the acoustic emission response index, while events such as gas flow, gas jets, pipeline vibration, and electromagnetic interference do not directly raise the acoustic emission response index, thereby reducing noise misjudgment during high-pressure gas cyclic loading.

[0041] When the inner ring acoustic emission response index Not less than Within a sliding time window, the following conditions must be met:

[0042] When the sliding time window that first meets the judgment condition is recorded, the pressure of the main test hole corresponding to that condition is recorded as the inner ring acoustic emission wake-up pressure. ; When the outer ring acoustic emission response index Not less than Within a sliding time window, the following conditions must be met:

[0043] When the sliding time window that first meets the condition is recorded, the pressure of the main test hole corresponding to that condition is recorded as the outer ring acoustic emission wake-up pressure. ; in, , The first The mean and standard deviation of the acoustic emission response index of the inner ring in the low-pressure background section before each cycle of boost; , The first The mean and standard deviation of acoustic emission response indices of the inner and outer rings in the low-pressure background section before each cycle of boost; The acoustic emission wake-up threshold coefficient. The number of consecutive time windows is used for discrimination.

[0044] If the inner ring acoustic emission response in a certain cycle does not meet the inner ring acoustic emission wake-up condition, the corresponding inner ring acoustic emission wake-up pressure is recorded as the upper limit of the cycle pressure of that cycle, or recorded as the inner ring not woken up state; if the outer ring acoustic emission response does not meet the outer ring acoustic emission wake-up condition, the corresponding outer ring acoustic emission wake-up pressure is recorded as the upper limit of the cycle pressure of that cycle, or recorded as the outer ring not woken up state, and this state is regarded as no premature response of outer ring acoustic emission has occurred in the outer ring fatigue intrusion judgment.

[0045] Furthermore, refer to Figure 5 The outer ring dynamic Felicity ratio is calculated using the following formula:

[0046] in, For the first The radial monitoring zone in the first The outer loop dynamic Felicity ratio in each cycle For the first The outer ring of the cycle emits acoustic emission to wake up the pressure. For the first The upper limit of cycle pressure for each cycle; when Earlier than the pressure limit of the previous cycle, This indicates that an early acoustic emission response has occurred in the outer control area of ​​the radial monitoring zone; When the first formal loop is When, in the formula Take the upper pressure limit of the last cycle of the baseline cycle segment. Alternatively, take the initial loop pressure limit set before the formal loop loading. .

[0047] The stability range of the outer ring dynamic Feliceti ratio is determined by the reference cycle segment:

[0048]

[0049] in, and The first The lower and upper limits of the dynamic Felicity ratio stability range of the outer ring of each radial monitoring zone. The mean of the dynamic Felicity ratio of the outer loop of the baseline cycle segment. The standard deviation of the dynamic Felicity ratio for the outer loop of the baseline cycle segment. This is the stability range coefficient.

[0050] The acoustic emission wake-up pressure difference between the inner and outer rings is calculated using the following formula:

[0051] in, For the first The radial monitoring zone in the first The pressure difference between the inner and outer loops of acoustic emission wake-up in each cycle; The average acoustic emission wake-up pressure difference between the inner and outer loops within the baseline cycle is:

[0052] The awakening pressure interval contraction index is calculated using the following formula:

[0053] in, Indicates the first The degree of interval contraction of the outer ring acoustic emission wake-up pressure relative to the inner ring acoustic emission wake-up pressure in each radial monitoring zone. To prevent stable terms with a denominator of zero, .

[0054] When cyclic fatigue damage is mainly confined to the near-field region of the main test port 1, the outer ring acoustic emission wake-up pressure lags significantly behind the inner ring acoustic emission wake-up pressure, and the difference between the inner and outer ring acoustic emission wake-up pressures is large. When fatigue damage develops towards the outer ring control region, the outer ring acoustic emission appears earlier, the difference between the inner and outer ring acoustic emission wake-up pressures decreases, and the wake-up pressure interval contraction index increases.

[0055] Furthermore, the outer ring surrounding rock stress cycle anomaly and the outer ring pore gas pressure cycle anomaly are used to characterize the outer ring mechanical anomaly and permeability anomaly caused by cyclic gas load, respectively.

[0056] No. In the loop, the th The anomalies in the outer ring surrounding rock stress circulation and the outer ring pore gas pressure circulation in the radial monitoring zones are as follows:

[0057]

[0058] in, For the first The time intervals corresponding to each cycle This represents the real-time value of the stress in the outer surrounding rock. This serves as the baseline for stress in the outer surrounding rock. This is the real-time value of the outer pore air pressure. This serves as the baseline for the outer pore air pressure. The reference stress and reference pore pressure are determined by the reference circulation section, and are as follows:

[0059]

[0060] in:

[0061]

[0062] The time interval corresponding to the baseline loop segment. The standard deviation of stress fluctuation in the outer ring of the baseline circulation section is given. The standard deviation of the pore pressure fluctuation in the outer ring of the reference circulation section. and For reference coefficients, and A positive stable term; When it is necessary to characterize the gas fatigue permeation response, the outer pore pressure growth rate is also calculated:

[0063] in, This represents the time interval for pore air pressure sampling.

[0064] Reference stress and reference pore pressure are used to normalize the cyclic anomalies of stress and cyclic anomalies of pore pressure in the outer ring surrounding rock, reducing the impact of dimensional differences and background fluctuations at different monitoring locations on the comprehensive judgment results.

[0065] Furthermore, refer to Figure 6 The outer ring fatigue intrusion index is calculated using the following formula:

[0066] in:

[0067] For the first The first radial monitoring zone The fatigue intrusion index of the outer ring of a cycle; For the outer circle dynamic Felicity; This represents the change in the dynamic Felicity ratio of the outer loops of adjacent cycles. To awaken the pressure interval contraction index; This represents the abnormal stress cycle of the outer surrounding rock. This refers to the abnormal amount of air pressure circulation in the outer pores; and These are the reference stress and the reference pore pressure, respectively. , , , , These are the weighting coefficients, and , .

[0068] The fatigue intrusion warning threshold is determined by the baseline loop segment:

[0069] in, For the first Fatigue intrusion warning threshold for each radial monitoring zone, and These are the mean and standard deviation of the fatigue intrusion index of the outer ring in the baseline cycle segment, respectively. This is the fatigue intrusion threshold coefficient; When the When a radial monitoring zone simultaneously meets the following conditions, it is determined that the radial monitoring zone has experienced outer ring fatigue intrusion:

[0070]

[0071] Furthermore, the outer ring dynamic Felicity ratio being below the lower limit of the stable range for at least [number] consecutive periods. One cycle; When multiple radial monitoring zones simultaneously meet the outer ring fatigue intrusion condition, select The largest radial monitoring zone is designated as the danger zone.

[0072] Furthermore, refer to Figure 7 After identifying the hazardous zone, the cyclic loading control unit 16 adjusts the subsequent cyclic air loading regime according to the degree of fatigue intrusion of the outer ring of the hazardous zone.

[0073] When fatigue intrusion of the outer ring is detected in the dangerous zone, the cyclic loading control unit adjusts the upper limit of the pressure for the next cycle according to the following formula:

[0074] in, This is the pressure upper limit attenuation coefficient; Define the normalized fatigue intrusion intensity:

[0075] The pressure upper limit attenuation coefficient Determine the segments according to the following formula:

[0076] in, , , The threshold for graded control, and ; , , Let be the pressure upper limit attenuation coefficient, and satisfy:

[0077] when Or the growth rate of air pressure in the outer pores Exceeding the maximum growth rate threshold At this time, the cyclic loading control unit terminates subsequent cyclic loading and performs a safety reduction. The cyclic loading control unit also reduces the boost rate for the next cycle based on the normalized fatigue intrusion intensity. Shorten the pressure holding time Or increase the low-pressure recovery time .

[0078] The monitoring, judgment and control methods described in this invention can also be applied to the identification of fatigue damage and the control of pressure regime in the surrounding rock of underground high-pressure gas storage facilities under actual repeated gas filling and releasing operation conditions.

Claims

1. A method for controlling the fatigue of circulating gas load in the surrounding rock of an underground high-pressure gas storage facility, characterized in that, include: According to the radial correspondence between the near-field inner ring monitoring holes and the far-field outer ring monitoring holes, the surrounding rock around the main test hole is divided into multiple radial monitoring zones. Each radial monitoring zone includes a near-field inner ring monitoring hole and a far-field outer ring monitoring hole located in the same radial monitoring profile. The surrounding rock of the main test hole is subjected to cyclic air loading according to a preset cyclic air loading regime, which includes a lower limit of cyclic pressure, an upper limit of cyclic pressure, a pressurization rate, a holding time, a depressurization rate, and a low-pressure recovery time. During the boost phase of each cycle, the inner and outer ring acoustic emission responses of each radial monitoring zone are obtained, and the inner ring acoustic emission wake-up pressure and outer ring acoustic emission wake-up pressure are extracted respectively. Based on the ratio between the outer ring acoustic emission wake-up pressure of the current cycle and the upper limit of the cycle pressure of the previous cycle, the outer ring dynamic Felicity ratio of each radial monitoring zone is determined. Based on the change of the pressure difference between the inner ring acoustic emission wake-up pressure and the outer ring acoustic emission wake-up pressure relative to the preset judgment benchmark, the wake-up pressure interval contraction index is determined. At least based on the degree of early wake-up of outer ring acoustic emission characterized by the outer ring dynamic Feliceti ratio, the decreasing trend of the outer ring dynamic Feliceti ratio in adjacent cycles, and the wake-up pressure interval contraction index, the outer ring fatigue intrusion index of each radial monitoring zone is determined, and whether outer ring fatigue intrusion occurs in each radial monitoring zone is determined according to a preset judgment criterion. When outer ring fatigue intrusion occurs in one or more of the radial monitoring zones, the subsequent cyclic air loading regime is adjusted. The adjustment includes one or more of the following: reducing the upper limit of the subsequent cycle pressure, reducing the pressurization rate, shortening the pressure holding time, increasing the low pressure recovery time, or terminating the cyclic loading.

2. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 1, characterized in that, Each cycle includes, in sequence, a pressurization phase, a pressure holding phase, a pressure reduction phase, and a low-pressure recovery phase; Before the boost phase of each formal cycle, the inner and outer acoustic emission response indices of each radial monitoring zone in the low-pressure background section are obtained respectively. The inner background threshold is determined according to the background mean, background standard deviation and preset acoustic emission wake-up threshold coefficient of the inner acoustic emission response index, and the outer background threshold is determined according to the background mean, background standard deviation and preset acoustic emission wake-up threshold coefficient of the outer acoustic emission response index. When the inner ring acoustic emission response in a loop does not meet the inner ring acoustic emission wake-up condition, the corresponding inner ring acoustic emission wake-up pressure is recorded as the upper limit of the loop pressure of that loop, or recorded as the inner ring not woken up state; When the outer ring acoustic emission response in a cycle does not meet the outer ring acoustic emission wake-up condition, the corresponding outer ring acoustic emission wake-up pressure is recorded as the upper limit of the cycle pressure of that cycle, or as the outer ring not woke-up state. In the outer ring fatigue intrusion determination, the outer ring not woke-up state is regarded as no outer ring acoustic emission premature response has occurred.

3. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 1, characterized in that, The preset judgment criterion is obtained from the benchmark cycle segment executed before the formal cyclic air load. The benchmark cycle segment includes multiple cycles, and its pressure upper limit is lower than the expected fatigue damage rapid development pressure and higher than the low pressure preload pressure. Within the reference cycle segment, the inner ring acoustic emission response, outer ring acoustic emission response, outer ring surrounding rock stress response, and outer ring pore air pressure response of each radial monitoring zone are collected to determine the acoustic emission background, the inner and outer ring acoustic emission wake-up pressure difference benchmark, the outer ring dynamic Feliceti ratio stability range, the outer ring surrounding rock stress baseline, the outer ring pore air pressure baseline, the reference stress, the reference pore air pressure, and the outer ring fatigue intrusion index early warning threshold.

4. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 1, characterized in that, Extracting the inner ring acoustic emission wake-up pressure and the outer ring acoustic emission wake-up pressure includes: Noise identification and event weighting are performed on acoustic emission events. The event weight of rock mass fracture acoustic emission events is set to 1, the event weight of gas flow noise, gas jet noise, pipeline vibration noise or electromagnetic interference noise is set to 0, and the event weight of suspected mixed events is set to greater than 0 and less than 1. Based on the event weights, acoustic emission events are retained, eliminated, or downweighted to obtain weighted acoustic emission event rate, weighted acoustic emission energy release rate, or a combination of the two, which serve as inner-ring acoustic emission response indicators and outer-ring acoustic emission response indicators. Using a sliding time window as the discrimination unit, the pressure of the main test hole corresponding to the sliding time window that first meets the discrimination condition is determined as the inner ring acoustic emission wake-up pressure or the outer ring acoustic emission wake-up pressure, respectively. The discrimination condition is that the inner ring acoustic emission response index or the outer ring acoustic emission response index exceeds the corresponding background threshold for no less than a preset number of consecutive sliding time windows.

5. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 3, characterized in that, The outer ring dynamic Feliceti ratio is the ratio of the outer ring acoustic emission wake-up pressure of the current cycle to the upper limit of the cycle pressure of the previous cycle. When the outer ring dynamic Feliceti ratio is less than 1, it indicates that the outer ring acoustic emission response occurs before reaching the upper limit of the cycle pressure of the previous cycle. The stability range of the outer ring dynamic ferrite ratio is determined based on the mean of the outer ring dynamic ferrite ratio within the reference cycle segment, the standard deviation of the outer ring dynamic ferrite ratio, and a preset stability range coefficient. The inner and outer ring acoustic emission wake-up pressure difference is determined based on the difference between the outer ring acoustic emission wake-up pressure and the inner ring acoustic emission wake-up pressure, and the wake-up pressure interval contraction index is determined based on the degree of reduction of the inner and outer ring acoustic emission wake-up pressure difference in the current cycle relative to the baseline inner and outer ring acoustic emission wake-up pressure difference in the reference cycle segment.

6. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 5, characterized in that, The outer ring fatigue intrusion index is determined based on the following factors according to preset weights: The outer ring dynamic felicity ratio represents the degree of early wake-up of outer ring acoustic emission; The degree of decrease in the outer loop dynamic ferriti ratio between adjacent cycles; The awakening pressure interval contraction index; The cyclic anomaly of the stress in the outer ring surrounding rock relative to the baseline of the stress in the outer ring surrounding rock within the corresponding cyclic time interval; And the cyclic anomaly of the outer ring pore pressure relative to the outer ring pore pressure baseline within the corresponding cycle time interval; The abnormal stress circulation of the outer ring surrounding rock is normalized by reference stress, and the abnormal pore pressure circulation of the outer ring is normalized by reference pore pressure. The reference stress and the reference pore pressure are determined based on the fluctuations of the outer ring surrounding rock stress and the fluctuations of the outer ring pore pressure within the reference circulation section.

7. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 6, characterized in that, When the outer ring fatigue intrusion index of a radial monitoring zone exceeds the corresponding outer ring fatigue intrusion index warning threshold, and the outer ring dynamic felicity ratio of the radial monitoring zone is continuously lower than the corresponding stable range lower limit for no less than a preset number of cycles, it is determined that the radial monitoring zone has experienced outer ring fatigue intrusion. When multiple radial monitoring zones simultaneously meet the outer ring fatigue intrusion condition, the radial monitoring zone with the largest outer ring fatigue intrusion index is identified as the dangerous zone, and the subsequent cyclic air load regime is adjusted according to the degree of outer ring fatigue intrusion of the dangerous zone.

8. The method for controlling the fatigue of circulating gas in the surrounding rock of an underground high-pressure gas storage facility according to claim 7, characterized in that, Based on the degree to which the fatigue intrusion index of the outer ring of the dangerous zone exceeds the warning threshold of the corresponding outer ring fatigue intrusion index, the normalized fatigue intrusion intensity is determined, and the upper limit of the cycle pressure of the next cycle is reduced according to the normalized fatigue intrusion intensity, so that the greater the normalized fatigue intrusion intensity, the greater the reduction in the upper limit of the cycle pressure of the next cycle. Furthermore, based on the normalized fatigue intrusion intensity, the pressure rise rate of the next cycle can be reduced, the pressure holding time of the next cycle can be shortened, or the low-pressure recovery time of the next cycle can be increased. When the normalized fatigue intrusion intensity reaches the limit control condition, or the outer ring pore pressure growth rate exceeds the limit growth rate threshold, the subsequent cyclic loading is terminated and a safe depressurization is performed.

9. A control system based on the circulating gas load fatigue control method for surrounding rock of an underground high-pressure gas storage facility according to any one of claims 1 to 8, characterized in that, It includes a main test hole, a high-pressure radial loading unit, a high-pressure air source, an inlet pressure regulating valve group, a pressure holding valve group, a pressure relief valve group, a pressure sensor, a near-field inner ring monitoring hole array, a far-field outer ring monitoring hole array, an inner ring acoustic emission sensor, an outer ring acoustic emission sensor, an outer ring surrounding rock stress sensor, an outer ring pore air pressure sensor, an acoustic emission acquisition module, an outer ring low-frequency acquisition module, and a cyclic loading control unit; The high-pressure radial loading unit is installed in the main test hole and connected to the high-pressure gas source through a high-pressure pipeline. The inlet pressure regulating valve group, the pressure holding valve group, the pressure relief valve group, and the pressure sensor are installed on the high-pressure pipeline. The near-field inner ring monitoring aperture array and the far-field outer ring monitoring aperture array are arranged around the main test aperture. The radial distance between the near-field inner ring monitoring aperture array and the main test aperture is smaller than the radial distance between the far-field outer ring monitoring aperture array and the main test aperture. The near-field inner ring monitoring aperture array and the far-field outer ring monitoring aperture array form multiple radial monitoring zones according to a radial correspondence. The inner ring acoustic emission sensor is disposed in the near-field inner ring monitoring hole array, and the outer ring acoustic emission sensor, the outer ring surrounding rock stress sensor and the outer ring pore air pressure sensor are disposed in the far-field outer ring monitoring hole array. The inner ring acoustic emission sensor and the outer ring acoustic emission sensor are connected to the acoustic emission acquisition module, and the outer ring surrounding rock stress sensor and the outer ring pore air pressure sensor are connected to the outer ring low frequency acquisition module. The pressure sensor, the acoustic emission acquisition module, and the outer ring low-frequency acquisition module are respectively connected to the cyclic loading control unit. The cyclic loading control unit is respectively connected to the intake pressure regulating valve group, the pressure holding valve group, and the pressure relief valve group. It is used to control the upper limit of cyclic pressure, the pressure increase rate, the pressure holding time, the pressure decrease rate, and the low pressure recovery time based on the acquired pressure signal, the inner and outer ring acoustic emission signals, the outer ring surrounding rock stress signal, and the outer ring pore air pressure signal.

10. The control system according to claim 9, characterized in that, The near-field inner ring monitoring aperture array includes four near-field inner ring monitoring apertures, and the far-field outer ring monitoring aperture array includes four far-field outer ring monitoring apertures. The four near-field inner ring monitoring holes and the four far-field outer ring monitoring holes are arranged circumferentially along the main test hole. One near-field inner ring monitoring hole and one far-field outer ring monitoring hole located in the same design azimuth angle or the same radial monitoring profile form a radial monitoring zone. When the azimuth deviation between the near-field inner ring monitoring hole and the far-field outer ring monitoring hole does not exceed the preset allowable deviation, the near-field inner ring monitoring hole and the far-field outer ring monitoring hole are regarded as being located in the same radial monitoring profile.

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