Experimental device and method for influence of circular inflation and deflation on air tightness of hard rock chamber

Abstract

The invention discloses an experimental device and method for the influence of circular inflation and deflation on the air tightness of a hard rock chamber. The experimental device comprises a hard rock chamber simulation body and an air path pipeline. The hard rock chamber simulation body is composed of an external surrounding rock and an internal concrete lining, a confining pressure applying device is arranged outside the surrounding rock, and a gas storage cavity is formed in the concrete lining; the gas circuit pipeline comprises a joint pipe with one end connected with the gas storage cavity, and the other end of the joint pipe is a gas filling pipe and a gas discharging pipe; the inflation pipe, the deflation pipe and the connector pipe are respectively provided with an air valve, an inflation flow meter is installed on the inflation pipe, a deflation flow meter is installed on the deflation pipe, and the air inlet end of the inflation pipe is connected with air supply equipment. A protection box is arranged outside the hard rock chamber simulation body; and the protection box is a sealed box body so as to separate the hard rock chamber simulation body from the outside. An air pressure sensor is arranged in the air storage cavity and can detect the air pressure in the air storage cavity. The device can be used for researching the influence of circular inflation and deflation on the concrete leakage rate.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage simulation test, and in particular to an experimental device and method for testing the influence of cyclical charging and discharging of gas on the air tightness of a hard rock chamber. Background Art

[0002] Compressed air energy storage technology is a new type of energy storage technology. As a large-scale physical energy storage technology, it can effectively solve the problem of large volatility of new clean energy and is an important direction for the future development of energy storage. Although the cost of artificial hard rock chambers as gas storage is relatively high at present, thanks to the rich and wide distribution of hard rock types, the dependence of salt caverns on salt rock formations has been effectively overcome. With the continuous development of excavation technology in the future, it is believed that the cost of hard rock chambers will also be greatly reduced. At present, the stability and airtightness of gas storage are the top priorities of research. The existing technology has not yet conducted in-depth research on the airtightness of artificial hard rock chambers, especially the impact on the concrete leakage rate during the cyclic charging and discharging process. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an experimental device and method for studying the influence of cyclic inflation and deflation on the air tightness of hard rock chambers, aiming to study the influence of cyclic inflation and deflation on the air leakage rate of concrete.

[0004] Technical solution: To achieve the above-mentioned purpose, an experimental device for the influence of cyclic inflation and deflation on the air tightness of a hard rock chamber of the present invention comprises a hard rock chamber simulation body and an air pipeline; the hard rock chamber simulation body is composed of external surrounding rock and internal concrete lining, the outside of the surrounding rock is provided with a confining pressure applying device, and the inside of the concrete lining is an air storage chamber; the air pipeline comprises a joint pipe having one end connected to the air storage chamber, and the other end of the joint pipe is forked into an inflation pipe and an deflation pipe; air valves are respectively provided on the inflation pipe, the deflation pipe and the joint pipe, an inflation flow meter is installed on the inflation pipe, and a deflation flow meter is installed on the deflation pipe, and the air inlet end of the inflation pipe is connected to the air supply equipment.

[0005] Furthermore, a protection box is provided outside the hard rock chamber simulation body, and the joint pipe passes through the protection box and is connected to the air storage cavity; the protection box is a sealed box to separate the hard rock chamber simulation body from the outside.

[0006] Furthermore, the surrounding rock application device includes a plurality of jacks arranged on the top of the surrounding rock and on the sides of the surrounding rock.

[0007] Furthermore, the gas supply equipment is an air pump.

[0008] Furthermore, an air pressure sensor is installed in the air storage cavity, and the air pressure sensor can detect the gas pressure in the air storage cavity.

[0009] Furthermore, an experimental method for an experimental device for studying the influence of cyclical inflation and deflation on the airtightness of hard rock chambers is provided, wherein multiple high-pressure gas inflation and deflation tests are conducted to study the influence of cyclical inflation and deflation on the airtightness of hard rock chambers; in a single high-pressure gas inflation and deflation test, gas is filled into a gas storage chamber through a gas supply device until a high-pressure gas environment is formed in the gas storage chamber, and after the high-pressure gas is stored for a certain period of time, the high-pressure gas is released until the gas environment in the gas storage chamber returns to its initial state; the gas flow rate during inflation and deflation is measured respectively, and the gas leakage amount in the gas storage chamber is obtained based on the difference in gas flow rate during inflation and deflation.

[0010] Furthermore, a single high-pressure gas charging and discharging test includes the following steps: step S1: start the confining pressure applying device to apply confining pressure to the surrounding rock; step S2: record the initial value of the air pressure measured by the air pressure sensor in the air storage chamber; step S3: close the air valve on the deflation pipe, open the air valves on the inflation pipe and the joint pipe; start the air supply equipment, and the air supply equipment fills the gas into the air storage chamber through the inflation pipe and the joint pipe; step S4: observe the readings of the air pressure sensor and the inflation flow meter, and when the reading on the air pressure sensor reaches the preset air pressure value, record the value of the inflation flow meter. Step S5: store the gas in the gas storage chamber for a period of time; Step S6: open the gas valves on the deflation pipe and the joint pipe to release the gas stored in the gas storage chamber, and observe the readings of the air pressure sensor and the deflation flowmeter. When the air pressure sensor returns to the recorded initial air pressure value, record the reading of the deflation flowmeter; Step S7: compare the reading of the inflation flowmeter during the inflation process with the reading of the deflation flowmeter during the deflation process, and obtain the gas leakage amount based on the calculated air flow difference.

[0011] Furthermore, before and after a single high-pressure gas charging and discharging test, the hard rock chamber simulation body is tested to see whether it is deformed due to pressure, thereby causing a change in the volume of the gas storage chamber; if the volume of the gas storage chamber changes before and after a single high-pressure gas charging and discharging test, the obtained gas leakage amount is corrected.

[0012] Furthermore, a gas pressure increase measurement test is performed before and after the single high-pressure gas charging and discharging test. In the single gas pressure increase measurement test, gas is filled into the gas storage chamber, and the gas flow rate required to increase the gas pressure in the gas storage chamber by a certain value is measured, and the gas flow rate is called the pressure increase gas flow rate. The pressure increase gas flow rates in the two gas pressure increase measurement tests are compared. If the pressure increase gas flow rate changes, it means that the volume of the gas storage chamber has also changed.

[0013] Furthermore, for the gas pressure boost measurement test, the pressure boost starting value and the pressure boost ending value are preset first, and the pressure boost starting value and the pressure boost ending value in each gas pressure boost measurement test remain unchanged; in a single gas pressure boost measurement test, the following steps are included: Step T1: Close the air valve on the deflation pipe, open the air valves on the inflation pipe and the connecting pipe, and then start the gas supply equipment to fill the gas into the gas storage chamber; Step T2: During the inflation process, the air pressure in the gas storage chamber is detected by the air pressure sensor; when the air pressure in the gas storage chamber reaches the pressure boost starting value, record the reading of the inflation flowmeter; when the air pressure in the gas storage chamber reaches the pressure boost ending value, record the reading of the inflation flowmeter again; the difference between the two recorded readings is the boost gas flow rate; Step T3: Turn off the gas supply equipment, close the air valve on the inflation pipe, open the air valve on the deflation pipe, and release the gas in the gas storage chamber.

[0014] Beneficial effects: The experimental device and method for the influence of cyclic gas filling and discharging on the air tightness of hard rock chambers of the present invention have the following beneficial effects:

[0015] 1) The inflation pipe inflates the gas into the gas storage cavity in the concrete lining, and the deflation pipe can release the gas in the gas storage cavity. The inflation pipe and the deflation pipe are respectively provided with an inflation flowmeter and a deflation flowmeter. During the inflation and deflation process, the gas flow rate of the gas filled into the gas storage cavity and the gas flow rate of the gas discharged from the gas storage cavity are respectively recorded. The difference between the two is the gas leakage in the gas storage cavity. Moreover, the device can realize cyclic inflation and deflation, which is convenient for studying the influence of cyclic inflation and deflation on the air tightness of the lining.

[0016] 2) Considering that the hard rock chamber simulation body may be deformed due to pressure during the test, which may cause the volume of the gas storage chamber to change; if the volume of the gas storage chamber changes, then the detection result of the gas leakage will be erroneous; therefore, the volume of the gas storage chamber is detected before and after the test, and the detection result of the gas leakage is corrected according to the volume change of the gas storage chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 It is an overall schematic diagram of the experimental device of the present invention;

[0018] Attached Figure 2 Schematic diagram of the surrounding rock application device. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] As attached Figures 1 to 2The experimental device for the effect of cyclic inflation and deflation on the air tightness of a hard rock chamber comprises a hard rock chamber simulation body 1 and an air pipeline. The hard rock chamber simulation body 1 is composed of an outer surrounding rock 2 and an inner concrete lining 3. A method for making the hard rock chamber simulation body 1 is as follows: a hollow steel sheet with a rectangular cross section and an annular steel sheet with a diameter smaller than the side length of the rectangle are used, the annular steel sheet is placed inside the rectangular steel sheet, and the central symmetry is ensured as much as possible. The surrounding rock 2 required for the test is poured in the space formed between the two steel sheets. The surrounding rock 2 can be made by mixing hard rock, water, etc. in proportion according to specific geological conditions; then the hollow steel sheet and the annular steel sheet are taken out, another annular steel sheet with a smaller diameter is set inside the surrounding rock 2, and the concrete lining 3 is poured inside the surrounding rock 2. After the concrete lining 3 is formed, the annular steel sheet with a smaller diameter is taken out; the interior of the concrete lining 3 is an air storage cavity 4, and then the two ends of the air storage cavity 4 in the concrete lining 3 are plugged with sealing plugs.

[0021] There is a confining pressure applying device outside the surrounding rock 2, such as the attached Figure 2 As shown in FIG. 1 , the surrounding rock 2 is square, and the surrounding rock 2 applying device includes a plurality of jacks 12 arranged on the top of the surrounding rock 2 and on the side of the surrounding rock 2 .

[0022] The gas pipeline includes a joint pipe 5, one end of which passes through the sealing plug and is connected to the air storage chamber 4, and the other end of the joint pipe 5 is bifurcated into an inflation pipe 6 and an air release pipe 7; the inflation pipe 6, the air release pipe 7 and the joint pipe 5 are respectively provided with air valves 8. An inflation flowmeter 9 is installed on the inflation pipe 6, and the inflation flowmeter 9 is used to measure the gas flow through the inflation pipe 6. A air release flowmeter 10 is installed on the air release pipe 7, and the air release flowmeter 10 is used to measure the gas flow through the air release pipe 7. The air inlet end of the inflation pipe 6 is connected to the air supply device, and the air supply device can fill the gas into the air storage chamber 4 through the inflation pipe 6 and the joint pipe 5. In one embodiment, the air supply device is an air pump 13. Through the cooperation of the air pump 13, the joint pipe 5, the inflation pipe 6 and the air release pipe 7, cyclic inflation and deflation are convenient, so as to study the influence of cyclic inflation and deflation on the air tightness of the concrete lining 3.

[0023] A protection box 11 is provided outside the hard rock chamber simulation body 1, and the joint pipe 5 passes through the protection box 11 and is connected to the air storage chamber 4; the protection box 11 is a sealed box to separate the hard rock chamber simulation body 1 from the outside.

[0024] An air pressure sensor 14 is installed in the air storage chamber 4 , and the air pressure sensor 14 can detect the gas pressure in the air storage chamber 4 .

[0025] The present invention provides an experimental method for an experimental device for studying the influence of cyclic gas charging and discharging on the air tightness of a hard rock chamber, and multiple high-pressure gas charging and discharging tests are performed to study the influence of cyclic gas charging and discharging on the air tightness of a hard rock chamber. In a single high-pressure gas charging and discharging test, gas is charged into the gas storage chamber 4 through a gas supply device until a high-pressure gas environment is formed in the gas storage chamber 4. After the high-pressure gas is stored for a certain period of time, the high-pressure gas is released until the gas environment in the gas storage chamber 4 returns to its initial state. The gas flow rate during the charging and discharging process is measured respectively, and the gas leakage amount in the gas storage chamber 4 is obtained based on the difference in the gas flow rate during the charging and discharging process.

[0026] The single high-pressure gas charging and discharging test includes the following steps:

[0027] Step S1: starting the confining pressure applying device, that is, starting each jack 12 to apply confining pressure to the surrounding rock 2;

[0028] Step S2: recording the initial value of the air pressure measured by the air pressure sensor 14 in the air storage chamber 4, thereby determining the initial gas environment in the air storage chamber 4;

[0029] Step S3: close the air valve 8 on the deflation pipe 7, open the air valves 8 on the inflation pipe 6 and the joint pipe 5; start the air supply device, and the air supply device fills the gas into the gas storage chamber 4 through the inflation pipe 6 and the joint pipe 5;

[0030] Step S4: preset a pressure value to be reached in the air storage chamber 4; observe the readings of the air pressure sensor 14 and the filling flow meter, and when the reading on the air pressure sensor 14 reaches the preset pressure value, record the reading of the filling flow meter 9, close the air valve 8 on the filling pipe 6 and the joint pipe 5, and turn off the air supply device;

[0031] Step S5: allowing the gas to be stored in the gas storage chamber 4 for a period of time;

[0032] Step S6: Open the air valve 8 on the air release pipe 7 and the joint pipe 5 to release the gas stored in the air storage chamber 4, and observe the readings of the air pressure sensor 14 and the air release flow meter 10 while releasing the gas. When the air pressure sensor 14 returns to the recorded initial air pressure value, record the reading of the air release flow meter 10;

[0033] Step S7: Compare the reading of the inflation flowmeter 9 during the inflation process with the reading of the deflation flowmeter 10 during the deflation process. If the readings recorded by the deflation flowmeter 10 are consistent with those recorded by the inflation flowmeter 9, it indicates that the gas in the gas storage chamber 4 has not leaked. If the reading of the deflation flowmeter 10 is less than the reading of the inflation flowmeter 9, it indicates that the gas in the gas storage chamber 4 has leaked. Based on the calculated airflow difference, the gas leakage amount is obtained.

[0034] Since the jack 12 applies pressure to the surrounding rock 2 during the high-pressure gas charging and discharging test, the hard rock chamber simulation body 1 may be deformed under the pressure, thereby reducing the volume of the gas storage chamber 4. When measuring the gas leakage, if the volume of the gas storage chamber 4 is reduced, the measured gas leakage will be less than the actual gas leakage. Therefore, the deformation of the gas storage chamber 4 must be considered when measuring the gas leakage.

[0035] Therefore, before and after a single high-pressure gas charging and discharging test, the hard rock chamber simulation body 1 is tested to see whether it is deformed due to pressure, thereby causing a change in the volume of the gas storage chamber 4. If the volume of the gas storage chamber 4 changes before and after a single high-pressure gas charging and discharging test, the obtained gas leakage amount is corrected to make the final gas leakage amount result more accurate.

[0036] The method for detecting whether the volume of the gas storage chamber 4 has changed is as follows: a gas pressure increase measurement test is performed before and after a single high-pressure gas charging and discharging test; in the single gas pressure increase measurement test, gas is filled into the gas storage chamber 4, and the gas flow rate required to increase the gas pressure in the gas storage chamber 4 to a certain value is measured, and the gas flow rate is called the pressure increase gas flow rate; the pressure increase gas flow rates in the two gas pressure increase measurement tests are compared, and if the pressure increase gas flow rate changes, it means that the volume of the gas storage chamber 4 has also changed.

[0037] For the gas pressure measurement test, the pressure start value and pressure end value are preset first. The pressure start value and pressure end value in each gas pressure measurement test remain unchanged, so as to control the test variables. In a single gas pressure measurement test, the following steps are included:

[0038] Step T1: close the air valve 8 on the deflation pipe 7, open the air valves 8 on the inflation pipe 6 and the joint pipe 5, and then start the gas supply device to fill the gas into the gas storage chamber 4;

[0039] Step T2: During the inflation process, the air pressure in the air storage chamber 4 is detected by the air pressure sensor 14; when the air pressure in the air storage chamber 4 reaches the boost start value, the reading of the inflation flow meter 9 is recorded; when the air pressure in the air storage chamber 4 reaches the boost end value, the reading of the inflation flow meter 9 is recorded again; the difference between the two recorded readings is the boost air flow rate;

[0040] Step T3: turn off the gas supply device, close the gas valve 8 on the gas charging pipe 6, open the gas valve 8 on the gas releasing pipe 7, and release the gas in the gas storage chamber 4.

[0041] In the gas boost measurement test, it should be noted that the boost start value and boost end value should not be too high, as excessive gas pressure may lead to gas leakage. For a single high-pressure gas charging and discharging test, if the values ​​of the two boost gas flow rates measured in the two gas boost measurement tests before and after the test are the same, it means that the volume of the gas storage chamber 4 has not changed, and the gas leakage measured in this high-pressure gas charging and discharging test does not need to be corrected; if the value of the boost gas flow rate in the latter test is smaller than that in the previous test, it means that the volume of the gas storage chamber 4 has become smaller. In this way, the gas leakage measured in this high-pressure gas charging and discharging test is too small and needs to be corrected by adding a certain value.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An experimental device for the effect of cyclical gas filling and discharging on the air tightness of hard rock chambers, characterized in that: The invention comprises a hard rock chamber simulation body (1) and a gas pipeline; the hard rock chamber simulation body (1) is composed of an external surrounding rock (2) and an internal concrete lining (3); a confining pressure applying device is provided on the outside of the surrounding rock (2), and an air storage chamber (4) is provided on the inside of the concrete lining (3); The air path pipeline comprises a joint pipe (5) having one end connected to the air storage chamber (4), and the other end of the joint pipe (5) is bifurcated into an air filling pipe (6) and an air release pipe (7); the air filling pipe (6), the air release pipe (7) and the joint pipe (5) are respectively provided with air valves (8); the air filling pipe (6) is provided with an air filling flow meter (9), the air release pipe (7) is provided with an air release flow meter (10), and the air inlet end of the air filling pipe (6) is connected to an air supply device.

2. The experimental device for measuring the effect of cyclic gas filling and discharging on the air tightness of hard rock chambers according to claim 1, characterized in that: The hard rock chamber simulation body (1) is provided with a protection box (11) outside, and the joint pipe (5) passes through the protection box (11) and is connected to the gas storage chamber (4); the protection box (11) is a sealed box body to separate the hard rock chamber simulation body (1) from the outside.

3. The experimental device for measuring the effect of cyclical gas filling and discharging on the air tightness of hard rock chambers according to claim 1, characterized in that: The surrounding rock (2) application device comprises a plurality of jacks (12) arranged on the top of the surrounding rock (2) and on the side of the surrounding rock (2).

4. The experimental device for measuring the effect of cyclic gas filling and discharging on the air tightness of hard rock chambers according to claim 1, characterized in that: The gas supply equipment is an air pump (13).

5. The experimental device for measuring the effect of cyclical inflation and deflation on the air tightness of hard rock chambers according to claim 1 is characterized in that: An air pressure sensor (14) is installed in the air storage chamber (4), and the air pressure sensor (14) can detect the gas pressure in the air storage chamber (4).

6. The experimental method of the experimental device for the effect of cyclic inflation and deflation on the air tightness of hard rock chambers according to claim 5, characterized in that: A plurality of high-pressure gas charging and discharging tests are carried out to study the influence of cyclic charging and discharging on the air tightness of the hard rock chamber; in a single high-pressure gas charging and discharging test, gas is charged into the gas storage chamber (4) through a gas supply device until a high-pressure gas environment is formed in the gas storage chamber (4); after the high-pressure gas is stored for a certain period of time, the high-pressure gas is released until the gas environment in the gas storage chamber (4) returns to its initial state; the gas flow rate during the charging and discharging process is measured respectively, and the gas leakage amount in the gas storage chamber (4) is obtained based on the difference in the gas flow rate during the charging and discharging process.

7. The experimental method of the experimental device for the effect of cyclic inflation and deflation on the air tightness of hard rock chambers according to claim 6 is characterized by: The single high-pressure gas charging and discharging test includes the following steps: Step S1: starting the confining pressure applying device to apply confining pressure to the surrounding rock (2); Step S2: recording the initial value of the air pressure measured by the air pressure sensor (14) in the air storage chamber (4); Step S3: closing the air valve (8) on the deflation pipe (7), and opening the air valves (8) on the inflation pipe (6) and the joint pipe (5); starting the air supply device, and the air supply device fills the air into the air storage chamber (4) through the inflation pipe (6) and the joint pipe (5); Step S4: Observe the readings of the air pressure sensor (14) and the inflation flow meter. When the reading on the air pressure sensor (14) reaches the preset air pressure value, record the reading of the inflation flow meter (9), close the air valve (8) on the inflation pipe (6) and the joint pipe (5), and turn off the air supply device; Step S5: allowing the gas to be stored in the gas storage chamber (4) for a period of time; Step S6: Open the air valve (8) on the air release pipe (7) and the joint pipe (5) to release the gas stored in the air storage chamber (4), and observe the readings of the air pressure sensor (14) and the air release flow meter (10). When the air pressure sensor (14) returns to the recorded initial air pressure value, record the reading of the air release flow meter (10); Step S7: Compare the reading of the inflation flow meter (9) during the inflation process with the reading of the deflation flow meter (10) during the deflation process, and obtain the gas leakage amount based on the calculated air flow difference.

8. The experimental method of the experimental device for the effect of cyclic gas filling and discharging on the air tightness of hard rock chambers according to claim 6 is characterized by: Before and after a single high-pressure gas charging and discharging test, a test is performed to determine whether the hard rock chamber simulation body (1) is deformed due to pressure, thereby causing a change in the volume of the gas storage chamber (4); if the volume of the gas storage chamber (4) changes before and after the single high-pressure gas charging and discharging test, the obtained gas leakage amount is corrected.

9. The experimental method of the experimental device for the effect of cyclic gas filling and discharging on the air tightness of hard rock chambers according to claim 8, characterized in that: Before and after a single high-pressure gas charging and discharging test, a gas pressure increase measurement test is performed respectively; in the single gas pressure increase measurement test, gas is charged into the gas storage chamber (4), and the gas flow rate required to increase the gas pressure in the gas storage chamber (4) by a certain value is measured, and this is referred to as the pressure increase gas flow rate; the pressure increase gas flow rates in the two gas pressure increase measurement tests are compared, and if the pressure increase gas flow rate changes, it means that the volume of the gas storage chamber (4) has also changed.

10. The experimental method of the experimental device for the effect of cyclic inflation and deflation on the air tightness of hard rock chambers according to claim 9, characterized in that: For the gas pressure measurement test, the pressure start value and the pressure end value are preset first, and the pressure start value and the pressure end value in each gas pressure measurement test remain unchanged; in a single gas pressure measurement test, the following steps are included: Step T1: close the air valve (8) on the deflation pipe (7), open the air valves (8) on the inflation pipe (6) and the joint pipe (5), and then start the air supply device to fill the gas into the gas storage chamber (4); Step T2: During the inflation process, the air pressure in the air storage chamber (4) is detected by the air pressure sensor (14); when the air pressure in the air storage chamber (4) reaches the pressure boosting start value, the reading of the air inflation flow meter (9) is recorded; when the air pressure in the air storage chamber (4) reaches the pressure boosting end value, the reading of the air inflation flow meter (9) is recorded again; the difference between the two recorded readings is the pressure boosting air flow rate; Step T3: Turn off the gas supply device, close the gas valve (8) on the gas charging pipe (6), open the gas valve (8) on the gas releasing pipe (7), and release the gas in the gas storage chamber (4).

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