An air tightness detection device and method for compressed air energy storage cavern surrounding rock

Abstract

This invention provides a device and method for testing the airtightness of surrounding rock in compressed air energy storage caverns. The device includes a testing probe extending into the borehole of the surrounding rock. Several expansion packers are fixedly connected to the testing probe, dividing the borehole into multiple independent airtightness testing chambers. The testing probe contains independent packer charging channels and several airtightness testing channels. The packer charging channels are connected to the expansion packers. The packer charging channels and airtightness testing channels are each connected to an external pressure supply system via independent pipes. Each pipe connected to the airtightness testing channels is equipped with a valve and a pressure monitoring sensor, which is electrically connected to a pressure monitoring system. The end of the testing probe is sealed and fixed to the surrounding rock surface via a sealing and fixing assembly. Each airtightness testing chamber can be tested independently, and airtightness parameters from multiple locations can be acquired simultaneously, significantly improving testing efficiency.

Description

Technical Field

[0001] This invention relates to the field of in-situ testing technology for underground engineering, and in particular to a device and method for detecting the air tightness of surrounding rock in compressed air energy storage caverns. Background Technology

[0002] Compressed air energy storage (CAES) power plants, as a new type of large-scale energy storage technology, rely on storing high-pressure gas exceeding 10 MPa in deep underground caverns. The sealing performance of the surrounding rock directly determines the safe operation and energy storage efficiency of the gas storage facility. Currently, CAES caverns generally adopt a composite lining structure of "shotcrete initial support + steel lining sealing." However, the shallow surrounding rock at a depth of 0-1 meter behind the steel lining (excavation damage zone EDZ) is prone to interconnected fissures due to blasting excavation. If these fissures are not identified and addressed in time, the high-pressure gas will diffuse along the fissures, leading to local instability, buckling, or even failure of the steel lining.

[0003] Current technologies for testing the air tightness of surrounding rock mainly rely on the "double-plug cross-type packer" device. Its working principle involves using two packers to isolate a single test section within the borehole. After inflation, the pressure decay is monitored. Once completed, the pressure must be released, and the device moved to the next depth for repeated operation. This technology suffers from the following intractable drawbacks: the traditional double-plug packer device has a test section spacing ≥500mm, making it impossible to achieve decimeter-level precision testing and easily masking local fractures; the testing process requires repeated device movement, which can easily scratch the borehole wall, causing secondary damage and leading to data distortion; the rigid sealing design at the borehole opening cannot adapt to rough concrete surfaces, resulting in a 0-10cm shallow testing blind zone; the single-segment, one-by-one testing mode is inefficient, with a single borehole test taking over 1.5 hours, and some devices have insufficient pressure resistance ratings, making it difficult to meet the high-pressure requirements of CAES cavern operations. Summary of the Invention

[0004] The purpose of this invention is to provide an airtightness testing device for the surrounding rock of compressed air energy storage caverns, which can solve the problems of low resolution, severe hole wall damage, blind spots in shallow areas, and low testing efficiency of existing testing technologies.

[0005] Therefore, the present invention adopts the following technical solution: A device for testing the airtightness of the surrounding rock of a compressed air energy storage cavern includes a testing probe extending into the borehole of the surrounding rock. Several expansion packers are fixedly connected to the testing probe, and these expansion packers are spaced apart along the axial direction of the testing probe, dividing the borehole into multiple independent airtightness testing chambers. The testing probe contains independent packer charging channels and several airtightness testing channels. The packer charging channels communicate with the expansion packers. The number of airtightness testing channels corresponds to the number of airtightness testing chambers and they are interconnected. The packer charging channels and the airtightness testing channels are each connected to an external pressure supply system via independent pipes. Each pipe connected to the airtightness testing channels is equipped with a valve and a pressure monitoring sensor. The pressure monitoring sensor is electrically connected to a pressure monitoring system. The end of the testing probe is sealed and fixedly connected to the surface of the surrounding rock via a sealing and fixing assembly. The length of the testing probe is greater than the depth of the borehole.

[0006] Based on the above technical solutions, the present invention may also employ the following further technical solutions, or combine these further technical solutions: The connecting sealing and fixing assembly includes a fastening nut and spherical washer assembly threaded to one end of the detection probe, a sealing pressure plate, and a flexible corrugated sealing gasket. The sealing pressure plate is located between the fastening nut and spherical washer assembly and the flexible corrugated sealing gasket. The area of ​​the sealing pressure plate is adapted to the area of ​​the flexible corrugated sealing gasket. The sealing pressure plate and the flexible corrugated sealing gasket are respectively provided with through holes for the detection probe to pass through. The flexible corrugated sealing gasket is fitted to the surrounding rock wall. The sealing pressure plate and the fastening nut and spherical washer assembly press the flexible corrugated sealing gasket tightly, thereby ensuring the sealing of the surrounding rock borehole.

[0007] The detection probe has several radial liquid outlet holes, the positions of which correspond to the positions of the expansion packer. The packer's charging channel is connected to the expansion packer through the radial liquid outlet holes. The detection probe also has several radial air outlet holes, the positions of which correspond to the airtightness test chamber. The airtightness test channel is connected to the airtightness test chamber through the radial air outlet holes.

[0008] The external pressure supply system includes a high-pressure nitrogen cylinder and a hydraulic pump. The packer charging channel is connected to the hydraulic pump through a pipeline, and the several airtightness test channels are each connected to the high-pressure nitrogen cylinder through independent pipelines.

[0009] The fastening nut and spherical washer assembly allows the sealing plate to deflect within a range of ±15°.

[0010] The pressure resistance rating of the packer's charging channel is ≥10MPa, and the radial pressure of the expanded packer after expansion is ≥6MPa.

[0011] The purpose of this invention is also to overcome the shortcomings of the prior art and provide a method for detecting the air tightness of the surrounding rock of a compressed air energy storage cavern, which can solve the problem of how to efficiently detect the air tightness inside the surrounding rock of a compressed air energy storage cavern.

[0012] Therefore, the present invention adopts the following technical solution: A method for testing the air tightness of the surrounding rock of a compressed air energy storage cavern includes the following steps: Step 1: Drill holes in the surrounding rock on the surface of the initial support of the compressed air energy storage cavern for testing air tightness, and clean the rock cuttings and dust from the holes. Step 2: Insert the detection probe with expansion seal along the borehole axis into the bottom of the hole, and install the flexible corrugated gasket, sealing pressure plate, fastening nut and spherical washer assembly in sequence at the end of the detection probe that protrudes from the hole. Tighten the fastening nut and spherical washer assembly, and transmit pressure through the sealing pressure plate to press the flexible corrugated gasket tightly against the surrounding rock surface around the hole. Step 3: The packer charging channel inside the test probe is connected to an external hydraulic pump through a pipeline. The hydraulic pump pumps hydraulic oil into the packer charging channel. The hydraulic oil is pumped into the expansion packer through the radial liquid outlet hole on the side wall of the test probe. After the expansion packer expands, it fits tightly against the borehole wall of the surrounding rock, thereby dividing the surrounding rock borehole into multiple independent sealed airtight test chambers. Step 4: Multiple airtightness test channels inside the test probe are connected to high-pressure nitrogen cylinders through multiple independent pipes. Each pipe is connected to a valve and a pressure monitoring sensor. By controlling the valve on each pipe, high-pressure gas is pumped into the airtightness test channel through the high-pressure nitrogen cylinder. The high-pressure gas enters different airtightness test chambers through the radial air outlet holes on the side wall of the test probe. A cross-interval air filling and monitoring method is adopted. First, high-pressure gas is introduced into the airtightness test chambers set at intervals, and the pressure changes in the remaining airtightness test chambers at normal pressure are monitored by the pressure monitoring sensor to determine the longitudinal through-cracks in the rock mass. Then, high-pressure gas is introduced into all airtightness test chambers to raise the pressure in each independent airtightness test chamber to the preset test pressure and stabilize the pressure. Step 5: Simultaneously monitor the pressure decay curves of each independent airtightness test chamber, determine the airtightness of the surrounding rock at the corresponding depth based on the pressure decay rate, and locate the fracture damage zone. Step 6: Release the pressure of each independent airtight test chamber and expansion packer in sequence, remove the flexible corrugated gasket, sealing pressure plate, fastening nut and spherical washer assembly, and slowly pull out the test probe to complete the test.

[0013] In step four, the preset test pressure shall not be lower than 50% of the design gas storage pressure of the compressed air energy storage cavern.

[0014] In step five, if the 30-minute pressure decay rate of a certain independent airtightness test chamber is greater than 10%, it is determined that there is a through-crack in the surrounding rock at that depth; if the pressure decay rate is less than or equal to 5%, it is determined that the airtightness of the surrounding rock at that depth meets the standard.

[0015] In step three, the charging pressure of the expansion packer is 1-2 MPa higher than the preset test pressure in step four to ensure the sealing and isolation effect between the expansion packers.

[0016] Compared with existing technologies, this invention has the following advantages and beneficial effects: It forms independent test chambers with a spacing of 50mm to 150mm using an array of micro-seal components, covering a depth of 0-1.2 meters in a single pass, achieving gradient distribution scanning of shallow surrounding rock airtightness. The damage zone positioning accuracy can reach ±5cm, precisely locating fracture damage areas. It can simultaneously acquire airtightness parameters from multiple locations, significantly improving detection efficiency. The "one-time entry, static testing" design avoids secondary damage to the borehole wall caused by repeated dragging of traditional devices, achieving one-time array-based micro-damage testing. Air tightness testing ensures that the test data is consistent with the actual air tightness of the surrounding rock; the orifice adaptive sealing seat solves the problem of extremely shallow sealing on rough shotcrete surfaces through the angle adjustment of the spherical hinge joint and the deformation fit of the flexible corrugated sealing gasket, achieving full coverage testing at depths of 0-1.2 meters; the test probe has a pressure resistance rating of ≥10MPa, and the test pressure can be flexibly adjusted according to actual working conditions; the modular design of each component makes installation and operation convenient, adaptable to test holes of different diameters, and can be widely used for surrounding rock testing in various CAES gas storage facilities such as salt caverns and artificial chambers. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a compressed air energy storage cavern surrounding rock air tightness testing device according to the present invention.

[0018] Figure 2 This is a cross-sectional schematic diagram of the detection probe of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote elements with the same or similar functions throughout. However, it should be understood that the drawings are for illustrative purposes only and should not be construed as limiting the present invention. To better illustrate this embodiment, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product size. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0021] This invention provides an airtightness testing device for the surrounding rock of a compressed air energy storage cavern, comprising a testing probe 1 extending into the borehole of the surrounding rock, with several expansion packers 2 fixedly connected to the testing probe 1. The expansion packers 2 are arranged at intervals along the axial direction of the testing probe 1, dividing the borehole of the surrounding rock into multiple independent airtightness testing chambers 3. The testing probe 1 is provided with mutually independent packer charging channels 11 and several airtightness testing channels 12. The packer charging channels 11 are connected to the expansion packers 2. The number of airtightness testing channels 12 corresponds to the number of airtightness testing chambers 3 and they are connected one by one. The packer charging channels 11 and airtightness testing channels 12 are respectively connected to an external pressure supply system through independent pipes. Each pipe connected to the airtightness testing channel 12 is respectively equipped with a valve 5 and a pressure monitoring sensor 9. The pressure monitoring sensor 9 is electrically connected to a pressure monitoring system 8. The end of the testing probe 1 is sealed and fixedly connected to the surface of the surrounding rock through a sealing and fixing assembly 4. The length of the testing probe 1 is greater than the depth of the borehole of the surrounding rock.

[0022] The connecting sealing and fixing assembly 4 includes a fastening nut and spherical washer assembly 41 threaded to one end of the detection probe 1, a sealing pressure plate 42, and a flexible corrugated sealing gasket 43. The sealing pressure plate 42 is located between the fastening nut and spherical washer assembly 41 and the flexible corrugated sealing gasket 43. The area of ​​the sealing pressure plate 42 is adapted to the area of ​​the flexible corrugated sealing gasket 43. The sealing pressure plate 42 and the flexible corrugated sealing gasket 43 are respectively provided with through holes for the detection probe 1 to pass through. The flexible corrugated sealing gasket 43 is set to fit against the surrounding rock wall. The flexible corrugated sealing gasket 43 is pressed tightly by the sealing pressure plate 42 and the fastening nut and spherical washer assembly 41, thereby ensuring the sealing of the surrounding rock borehole.

[0023] like Figure 1As shown, in this embodiment, the detection probe 1 is provided with 8 expansion packers 2 at axial intervals, thereby dividing the surrounding rock borehole into 8 independent airtight test chambers 3. The tail expansion packers 2 are arranged close to the bottom of the hole, and the uppermost airtight test chamber 3 is sealed by a flexible corrugated sealing gasket 43.

[0024] like Figure 2 As shown, in this embodiment, the packer charging channel 11 is located at the axis of the detection probe 1, and the expansion packer 2 is arranged around the packer charging channel 11 in a circumferential manner. There are a total of 8 airtightness test channels 12, and each airtightness test channel 12 is independently connected to the corresponding airtightness test chamber 3.

[0025] The number of expansion seals 2 connected to the detection probe 1 can be selected according to the actual working conditions.

[0026] The detection probe 1 has several radial liquid outlet holes, the positions of which correspond to the positions of the expansion packer 2. The packer charging channel 11 is connected to the expansion packer 2 through the radial liquid outlet holes. The detection probe 1 also has several radial air outlet holes, the positions of which correspond to the airtightness test chamber 3. The airtightness test channel 12 is connected to the airtightness test chamber 3 through the radial air outlet holes.

[0027] The external pressure supply system includes a high-pressure nitrogen cylinder 6 and a hydraulic pump 7. The packer charging channel 11 is connected to the hydraulic pump 7 through a pipeline, and several airtightness test channels 12 are connected to the high-pressure nitrogen cylinder 6 through independent pipelines.

[0028] The fastening nut and spherical washer assembly 41 allows the sealing pressure plate 42 to deflect within ±15°.

[0029] The pressure resistance rating of the packer charging channel 11 is ≥10MPa, and the radial pressure of the expansion packer 2 after expansion is ≥6MPa.

[0030] The detection probe 1 adopts a bundled armored structure, which includes a central pressure-bearing steel pipe, several stainless steel capillary tubes evenly distributed around it, and an outer protective tube. The spaces between the tubes are filled with cured resin. The detection probe 1 is made of stainless steel or titanium alloy, with a total length of 1.2 meters to 1.5 meters, and is suitable for test holes with a diameter of 75 mm to 100 mm. The expansion seal 2 is made of high-pressure resistant and wear-resistant rubber. After expansion, it fits tightly against the hole wall to ensure a sealed isolation between the test chambers. It has an internal anti-protrusion reinforcement skeleton, and its two ends are connected to the detection probe through metal anchoring sleeves with sealing rings. 1. Tightly fixed connection, its radial pressure after expansion is ≥6MPa, the effective axial sealing length of the expansion packer 2 is 20mm~35mm, and the center distance between adjacent packers is 50mm~150mm; the thickness of the flexible corrugated sealing gasket 43 is 15mm~25mm, made of closed-cell foam rubber or silicone rubber, and the angle of the sealing pressure plate is adaptively adjusted through a ball joint. Combined with the deformation and fitting characteristics of the flexible corrugated sealing gasket, it can tightly fit the rough shotcrete surface, prevent the escape of extremely shallow gas of 0-10cm from the orifice, and eliminate the detection blind zone.

[0031] This invention provides a method for detecting the airtightness of the surrounding rock of a compressed air energy storage cavern, comprising the following steps: Step 1: Drill holes in the surrounding rock on the surface of the initial support of the compressed air energy storage cavern for testing air tightness, and clean the rock cuttings and dust from the holes. Step 2: Insert the detection probe 1 with expansion seal 2 into the bottom of the borehole along the axis of the surrounding rock borehole, and install the flexible corrugated sealing gasket 43, sealing pressure plate 42, fastening nut and spherical washer assembly 41 in sequence at the end of the detection probe 1 that protrudes from the borehole opening. Tighten the fastening nut and spherical washer assembly 41, and transmit pressure through the sealing pressure plate 42 to press the flexible corrugated sealing gasket 43 tightly against the surrounding rock surface around the borehole opening. Step 3: The packer charging channel 11 inside the test probe 1 is connected to an external hydraulic pump 7 through a pipeline. The hydraulic pump 7 pumps hydraulic oil into the packer charging channel 11. The hydraulic oil is pumped into the expansion packer 2 through the radial liquid outlet hole on the side wall of the test probe 1. After the expansion packer 2 expands, it fits tightly against the borehole wall of the surrounding rock, thereby dividing the surrounding rock borehole into multiple independent sealed airtight test chambers 3. Step 4: Multiple airtightness test channels 12 inside the test probe 1 are connected to high-pressure nitrogen cylinders 6 through multiple independent pipes. Each pipe is connected to a valve 5 and a pressure monitoring sensor 9. By controlling the valve 5 on each pipe, high-pressure gas is pumped into the airtightness test channel 12 through the high-pressure nitrogen cylinder 6. The high-pressure gas enters different airtightness test chambers 3 through the radial air outlet holes on the side wall of the test probe 1. A cross-interval gas filling and monitoring method is adopted. First, high-pressure gas is introduced into the airtightness test chambers 3 that are set at intervals. The pressure changes in the airtightness test chambers 3 under normal pressure are monitored by the pressure monitoring sensor 9 to determine the longitudinal through-cracks in the rock mass. Then, high-pressure gas is introduced into all airtightness test chambers 3 to raise the pressure in each independent airtightness test chamber 3 to the preset test pressure and stabilize the pressure. Step 5: Simultaneously monitor the pressure decay curves of each independent airtightness test chamber 3, determine the airtightness of the surrounding rock at the corresponding depth based on the pressure decay rate, and locate the fracture damage zone. Step 6: Release the pressure of each independent airtight test chamber 3 and expansion seal 2 in sequence, remove the flexible corrugated sealing gasket 43, sealing pressure plate 42, fastening nut and spherical washer assembly 41, and slowly pull out the test probe 1 to complete the test.

[0032] In step four, the preset test pressure shall not be lower than 50% of the design gas storage pressure of the compressed air energy storage cavern.

[0033] In step five, when the 30-minute pressure decay rate of a certain independent airtightness test chamber 3 is greater than 10%, it is determined that there is a through-crack in the surrounding rock at that depth; when the pressure decay rate is less than or equal to 5%, it is determined that the airtightness of the surrounding rock at that depth meets the standard.

[0034] In step three, the charging pressure of the expansion packer 2 is 1 MPa to 2 MPa higher than the preset test pressure in step four, to ensure the sealing and isolation effect between the expansion packers 2.

[0035] In step one, the drilling depth of the surrounding rock borehole is 0.5 meters to 1.2 meters; in step two, the end of the borehole reaction frame pressure detection probe 1 can be installed; in step four, the preset test pressure can be 3MPa to 8MPa; in step five, the monitoring time is 30 minutes to 60 minutes; in step six, during the inflation process, the inflation rate is controlled by the pressure regulating valve to be 0.1MPa / s to 0.3MPa / s.

[0036] Each independent test chamber is inflated in parallel and monitored synchronously, significantly improving testing efficiency. Testing at a depth of 0-1.2 meters can be completed in just 40-60 minutes. Based on the pressure decay curves of each test chamber, the depth and extent of the crack damage zone can be accurately located, providing a basis for targeted treatment.

[0037] Example 1: Applicable to shallow surrounding rock detection at a depth of 1 meter.

[0038] 1) Test probe 1: Made of 304 stainless steel, with a total length of 1.5 meters and an outer diameter of 50 mm. It adopts a bundled armored structure. A high-pressure resistant seamless steel pipe with an inner diameter of 6 mm is arranged in the center as the sealing component charging channel 11. Eight stainless steel capillary tubes with an inner diameter of 3 mm are arranged around it as airtight test channels 12. The tube bundles are filled with high-strength epoxy resin for curing. The outermost layer is nested with a stainless steel protective tube.

[0039] 2) Expansion packer 2: Includes 8 expansion packers 2, each packer has an effective axial sealing length of 25mm, and is made of high-pressure resistant nitrile rubber with an internal steel wire braided skeleton; both ends of the expansion packer 2 are fixed to the detection probe 1 by metal anchor sleeves, and the anchor sleeves are equipped with high-pressure resistant O-rings. The detection probe 1 has radial liquid outlet holes on its side wall that connect to the inner cavity of the expansion packer 2; the center distance between adjacent expansion packers 2 is 125mm, which corresponds to 8 independent airtightness test chambers 3, and the axial length of each test chamber is 100mm.

[0040] 3) Sealing and fixing assembly 4: The fastening nut and spherical washer assembly 41 is threaded to the tail end of the detection probe 1. The angle of the pressure plate is adaptively adjusted by the sliding of the spherical washer. The sealing pressure plate 42 is a circular steel plate with a diameter of 150mm. The flexible corrugated sealing gasket 43 is made of closed-cell foam rubber with a thickness of 20mm. A transverse reaction frame is added on the outside of the orifice and fixed to the rock surface by anchor rods to press the tail end of the detection probe 1 to counteract the axial thrust of the high-pressure gas.

[0041] (2) Detection method and steps S1: Drilling preparation: On the surface of the initial support of the shotcrete in the CAES cavern, a geological drilling rig is used to drill a 75mm diameter and 1m deep hole in the surrounding rock. High-pressure airflow is used to clean the rock cuttings and dust in the hole to ensure that there is no loose rock mass on the hole wall. S2: Probe installation: Slowly insert the test probe into the bottom of the test hole along the axis of the test hole, tighten the fastening nut and spherical washer assembly 41, so that the flexible corrugated sealing gasket 43 fits tightly against the sprayed concrete surface around the hole opening to ensure the hole opening is sealed. S3: Packer charging: Start hydraulic pump 7 and inject hydraulic oil into each expansion packer 2 through packer charging channel 11, pressurize to 7MPa, so that the expansion packer 2 expands synchronously and fits tightly against the borehole wall, dividing the surrounding rock borehole into 8 airtight test chambers 3. S4: Multi-stage inflation test: Turn off hydraulic pump 7, start high-pressure nitrogen cylinder 6, adjust pressure regulating valve to make inflation rate 0.2MPa / s, introduce nitrogen into each independent airtightness test chamber 3, pressurize to 5MPa and stabilize pressure for 5min; S5: Data Acquisition and Analysis: The pressure decay data of each independent airtight test chamber 3 is recorded synchronously through the pressure monitoring system for 30 minutes; the monitoring results show that the 30-minute pressure decay rate of the first and second test chambers (corresponding to a depth of 0-20cm) is 15% and 12% respectively, and the pressure decay rate of the third to eighth test chambers (corresponding to a depth of 20-100cm) is ≤4%, and the depth of the excavation damage zone of the shallow surrounding rock is determined to be 20cm; S6: Test completion: First, release the nitrogen pressure in each independent airtight test chamber 3 through the pressure relief valve, then release the oil pressure of the hydraulic pump 7 to cause the expansion seal 2 to contract and reset, and slowly pull out the test probe; according to the test results, perform cement grouting treatment on the damaged area with a depth of 0-20cm, and design the length of the steel lining anchor nail to be 35cm.

[0042] Example 2: The difference between this example and Example 1 is that: the number of expansion packers 2 is 6, the effective axial sealing length is 30mm, and the first and last expansion packers 2 are arranged close to the orifice sealing gasket and the bottom of the orifice, respectively, thereby forming 5 independent airtight test chambers 3 between the 6 packers. The center distance between adjacent expansion packers 2 is 110mm, and the single test coverage depth is 0.5m. The preset test pressure in step S4 of the detection method is 6MPa, and the monitoring time is 60min. It is suitable for CAES cavern scenarios where the shallow surrounding rock damage zone is relatively shallow and the detection accuracy requirements are higher.

[0043] Based on the description and accompanying drawings of this invention, those skilled in the art can easily manufacture or use the device and method for detecting the air tightness of the surrounding rock of a compressed air energy storage cavern, and can achieve the positive effects described in this invention.

[0044] It should be noted that the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "installed," "set," "equipped with," "connected," "linked," and "sleeve" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral construction; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two mechanisms, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In the description of this invention, it should be understood that the terms "one end," "the other end," "outer side," "inner side," "horizontal," "end," "length," "outer end," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. The terms "first" and "second" are also used only for the sake of brevity in description and do not indicate or imply relative importance.

[0046] Furthermore, in practicing the claims of this invention, those skilled in the art can understand and influence variations to the disclosed embodiments through a study of the drawings, the disclosure, and the appended claims. Additionally, in the claims and description, words such as "comprising" and "containing" do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made in accordance with the present invention are covered by the scope of the claims of the present invention, and will not be listed here.

Claims

1. A compressed air energy storage cavern surrounding rock air tightness detection device, characterized in that, The test includes a test probe (1) that extends into the borehole of the surrounding rock. Several expansion packers (2) are fixedly connected to the test probe (1). These expansion packers (2) are spaced apart along the axial direction of the test probe (1), dividing the borehole into multiple independent airtightness test chambers (3). The test probe (1) contains independent packer charging channels (11) and several airtightness test channels (12). The packer charging channels (11) communicate with the expansion packers (2). The number of airtightness test channels (12) is... Corresponding to the number of airtight test chambers (3) and connected one by one, the packer charging channel (11) and the airtight test channel (12) are respectively connected to an external pressure supply system through independent pipes. Each pipe connected to the airtight test channel (12) is equipped with a valve (5) and a pressure monitoring sensor (9). The pressure monitoring sensor (9) is electrically connected to a pressure monitoring system (8). The end of the detection probe (1) is sealed and fixed to the surrounding rock surface through a sealing and fixing assembly (4). The length of the detection probe (1) is greater than the depth of the surrounding rock borehole.

2. The compressed air energy storage cavern surrounding rock gas tightness detection device according to claim 1, characterized in that, The connecting sealing and fixing assembly (4) includes a fastening nut and spherical washer assembly (41) threaded to one end of the detection probe (1), a sealing pressure plate (42), and a flexible corrugated sealing gasket (43). The sealing pressure plate (42) is located between the fastening nut and spherical washer assembly (41) and the flexible corrugated sealing gasket (43). The area of ​​the sealing pressure plate (42) is adapted to the area of ​​the flexible corrugated sealing gasket (43). The sealing pressure plate (42) and the flexible corrugated sealing gasket (43) are respectively provided with through holes for the detection probe (1) to pass through. The flexible corrugated sealing gasket (43) is set in contact with the surrounding rock wall. The flexible corrugated sealing gasket (43) is pressed by the sealing pressure plate (42) and the fastening nut and spherical washer assembly (41), thereby ensuring the sealing of the surrounding rock borehole.

3. The compressed air energy storage cavern surrounding rock gas tightness detection device of claim 1, wherein, The detection probe (1) is provided with a plurality of radial liquid outlet holes, the positions of which correspond to the positions of the expansion packer (2). The packer charging channel (11) is connected to the expansion packer (2) through the radial liquid outlet holes. The detection probe (1) is also provided with a plurality of radial air outlet holes, the positions of which correspond to the airtightness test chamber (3). The airtightness test channel (12) is connected to the airtightness test chamber (3) through the radial air outlet holes.

4. The compressed air energy storage cavern surrounding rock gas tightness detection device of claim 1, wherein, The external pressure supply system includes a high-pressure nitrogen cylinder (6) and a hydraulic pump (7). The packer charging channel (11) is connected to the hydraulic pump (7) through a pipeline. Several airtightness test channels (12) are connected to the high-pressure nitrogen cylinder (6) through independent pipelines.

5. The compressed air energy storage cavern surrounding rock gas tightness detection device of claim 2, wherein, The fastening nut and spherical washer assembly (41) allows the sealing pressure plate (42) to deflect within a range of ±15°.

6. The compressed air energy storage cavern surrounding rock gas tightness detection device of claim 1, wherein, The pressure resistance level of the packer charging channel (11) is ≥10MPa, and the radial pressure of the expanded packer (2) after expansion is ≥6MPa.

7. A method for detecting the air tightness of the surrounding rock of a compressed air energy storage cavern, characterized in that, Includes the following steps: Step 1: Drill holes in the surrounding rock on the surface of the initial support of the compressed air energy storage cavern for testing air tightness, and clean the rock cuttings and dust from the holes. Step 2: Insert the detection probe (1) with expansion seal (2) into the bottom of the hole along the borehole axis, and install the flexible corrugated gasket (43), sealing pressure plate (42), fastening nut and spherical washer assembly (41) in sequence at the end of the detection probe (1) that protrudes from the hole opening. Tighten the fastening nut and spherical washer assembly (41), and transmit pressure through the sealing pressure plate (42) to press the flexible corrugated gasket (43) tightly against the surrounding rock surface around the hole opening; Step 3: The packer charging channel (11) inside the test probe (1) is connected to a hydraulic pump (7) via a pipeline. The hydraulic pump (7) pumps hydraulic oil into the packer charging channel (11). The hydraulic oil is pumped into the expansion packer (2) through the radial outlet hole on the side wall of the test probe (1). After the expansion packer (2) expands, it fits tightly against the borehole wall of the surrounding rock, thereby dividing the surrounding rock borehole into multiple independent sealed airtight test chambers (3). Step 4: The multiple airtightness test channels (12) inside the detection probe (1) are connected to high-pressure nitrogen cylinders (6) through multiple independent pipes. Each pipe is connected to a valve (5) and a pressure monitoring sensor (9). The valve (5) on each pipe is controlled to pump high-pressure gas into the airtightness test channel (12) through the high-pressure nitrogen cylinder (6). The high-pressure gas enters different airtightness test chambers (3) through the radial air outlet holes on the side wall of the detection probe (1). The cross-interval gas filling and monitoring method is adopted. First, high-pressure gas is introduced into the airtightness test chambers (3) set at intervals. The pressure change in the airtightness test chambers (3) under normal pressure is monitored by the pressure monitoring sensor (9) to determine the longitudinal through-cracks in the rock mass. Then, high-pressure gas is introduced into all airtightness test chambers (3) to raise the pressure in each independent airtightness test chamber (3) to the preset test pressure and stabilize the pressure. Step 5: Simultaneously monitor the pressure decay curves of each independent airtightness test chamber (3), determine the airtightness of the surrounding rock at the corresponding depth based on the pressure decay rate, and locate the fracture damage zone. Step 6: Release the pressure of each independent airtight test chamber (3) and expansion packer (2) in sequence, remove the flexible corrugated gasket (43), sealing pressure plate (42), fastening nut and spherical washer assembly (41), and slowly pull out the test probe (1) to complete the test.

8. The method for detecting the air tightness of the surrounding rock of a compressed air energy storage cavern according to claim 7, characterized in that, In step four, the preset test pressure shall not be lower than 50% of the design gas storage pressure of the compressed air energy storage cavern.

9. The method for detecting the airtightness of the surrounding rock of a compressed air energy storage cavern as described in claim 7, characterized in that, In step five, when the 30-minute pressure decay rate of a certain independent airtightness test chamber (3) is greater than 10%, it is determined that there is a through crack in the surrounding rock at that depth; when the pressure decay rate is less than or equal to 5%, it is determined that the airtightness of the surrounding rock at that depth meets the standard.

10. The method of claim 7, wherein the method further comprises: determining the air tightness of the surrounding rock of the compressed air energy storage cavern based on the measured pressure difference. In step three, the charging pressure of the expansion packer (2) is 1 MPa to 2 MPa higher than the preset test pressure in step four, to ensure the sealing and isolation effect between the expansion packers (2).

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