Pressure-maintaining drainage system suitable for compressed air energy storage cavern

Abstract

The invention discloses a pressure-maintaining drainage system suitable for a compressed air energy storage cavern, which comprises a prefabricated reinforced concrete pipe, an annular drainage pipe, a drainage blind pipe, a plug water delivery pipe, an underground reservoir, a drainage valve, a water suction pump and a water outlet pipe, and is characterized in that the prefabricated reinforced concrete pipe is axially arranged between a secondary lining and a primary lining along the bottom of the cavern; the annular drainage pipes are distributed at intervals in the axial direction of the cavern, each annular drainage pipe is located between the second lining and the first lining, the bottom of each annular drainage pipe is communicated with the prefabricated reinforced concrete pipe, each annular drainage pipe is communicated with a plurality of drainage blind pipes, and each drainage blind pipe is embedded in the first lining in a penetrating mode. One end of the plug water delivery pipe is communicated with the prefabricated reinforced concrete pipe, the other end of the plug water delivery pipe vertically extends into the underground reservoir and is provided with a drainage valve, and the water suction pump is arranged at the bottom of the underground reservoir and connected with the water outlet pipe which extends to the ground surface. The system has drainage and pressure maintaining functions, and is beneficial to improving the air tightness, corrosion resistance and structural stability of the compressed air energy storage cavern.

Description

Technical Field

[0001] The invention relates to the technical field of underground energy storage, and in particular to a pressure-maintaining drainage system suitable for a compressed air energy storage cavern. Background Art

[0002] Compressed air energy storage technology is regarded as one of the most promising physical energy storage technologies due to its advantages such as large capacity, low cost, long life and environmental friendliness. In the technology of compressed air energy storage, how to ensure that the gas in the underground gas storage cavern does not leak or control the leakage within the allowable value is a key issue in compressed air energy storage technology. Therefore, the storage of high-pressure air in a lined cavern composed of a sealing layer, a concrete lining and surrounding rock has been proposed to effectively solve this key problem. Among them, the surrounding rock bears the gas storage pressure of the cavern, the lining transmits the pressure, and the sealing layer seals the gas stored in the cavern.

[0003] For conventional underground caverns, in order to keep the underground cavern environment dry and prevent groundwater from accumulating outside the lining to form external water pressure and damage the lining structure, a drainage system is usually set outside the lining. During the service of conventional caverns, the pore water that penetrates from the surrounding rock into the underground cavern will be collected and discharged from the cavern by the drainage system outside the lining. Therefore, there will be no accumulation of groundwater in the lining and surrounding rock around the conventional underground cavern, and the water pressure around the drainage system and lining is atmospheric pressure. The biggest feature of the artificial compressed gas energy storage cavern compared with the conventional underground cavern is that the compressed gas energy storage cavern must withstand the high gas internal pressure during operation. The accumulation of water pressure around the cavern under the action of high gas internal pressure will not only not cause damage to the cavern structure, but also play a certain role in offsetting the high internal pressure in the cavern, which is beneficial to the safety of the cavern structure (lining, drainage system, etc.). In addition, the groundwater accumulated in the lining and surrounding rock around the cavern will also hinder the further penetration of the gas that has penetrated the sealing layer, which is beneficial to the air tightness of the cavern. Therefore, it is inappropriate to set up the drainage system of a conventional cavern for a high internal pressure cavern such as a compressed air energy storage cavern. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a pressure-maintaining drainage system suitable for a compressed air energy storage cavern in view of the characteristics of the compressed air energy storage cavern, which has both drainage and pressure-maintaining functions, and is beneficial to improving the air tightness, corrosion resistance and structural stability of the compressed air energy storage cavern.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a pressure-maintaining drainage system suitable for a compressed air energy storage cavern, wherein the compressed air energy storage cavern is arranged in an underground surrounding rock, and the compressed air energy storage cavern includes a primary lining, a secondary lining and a sealing layer, wherein the sealing layer is tightly attached to the inner surface of the secondary lining, and a vertical shaft directly connected to the surface is arranged on one side of the compressed air energy storage cavern, and an underground water reservoir is isolated and arranged at the bottom of the vertical shaft, characterized in that: the pressure-maintaining drainage system includes a prefabricated reinforced concrete pipe arranged inside the compressed air energy storage cavern, a row of annular drainage pipes, several drainage blind pipes, and a plugged water pipe arranged outside the compressed air energy storage cavern, an underground water reservoir, an electrically controlled drainage valve, a water pump and a water outlet pipe, wherein the prefabricated reinforced concrete pipe is arranged along the compressed air energy storage cavern The axial arrangement of the bottom of the chamber, the precast reinforced concrete pipe is located between the secondary lining and the primary lining, the annular drainage pipe is distributed at intervals along the axial direction of the compressed air energy storage cavern, each ring of the annular drainage pipe is located between the secondary lining and the primary lining, the bottom of each ring of the annular drainage pipe is connected with the precast reinforced concrete pipe, each ring of the annular drainage pipe is connected with a plurality of drainage blind pipes, each drainage blind pipe penetrates and is buried in the primary lining, one end of the plug water pipe is connected with the precast reinforced concrete pipe, the other end of the plug water pipe vertically extends into the underground water reservoir and is installed with the drainage valve, the water pump is arranged at the bottom of the underground water reservoir, the water pump is connected with the outlet pipe, and the outlet pipe extends to the surface;

[0006] During the construction and maintenance of the compressed air energy storage cavern, the drainage valve is opened, and the groundwater infiltrated in the underground surrounding rock enters the row of annular drainage pipes through the several drainage blind pipes and merges into the prefabricated reinforced concrete pipes, and then flows into the underground water storage tank along the prefabricated reinforced concrete pipes and the plug water pipes under the action of gravity, and finally is discharged to the surface through the pump and the outlet pipe, thereby playing a drainage role;

[0007] During the operation of the compressed air energy storage cavern, the drainage valve is closed, and the groundwater that penetrates into the primary lining and the secondary lining from the underground surrounding rock cannot be discharged. It will gradually accumulate in the primary lining, the secondary lining, the drainage blind pipe, the annular drainage pipe, the prefabricated reinforced concrete pipe, the plug water pipe and the surrounding rock around the compressed air energy storage cavern outside the sealing layer and generate a certain head pressure. The head pressure acts as an external pressure to offset part of the internal pressure of the compressed air energy storage cavern, thereby playing a certain pressure-maintaining role, which is beneficial to improving the air tightness, corrosion resistance and structural stability of the compressed air energy storage cavern.

[0008] Preferably, a maintenance passage is provided on one side of the shaft, the bottom of which leads to the compressed air energy storage cavern, and the plug water pipe is located below the maintenance passage to facilitate construction and maintenance by personnel.

[0009] Preferably, along the axial direction of the compressed air energy storage cavern, the spacing between two adjacent rings of annular drainage pipes is 3 to 5 m.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] (1) The present invention provides a pressure-maintaining drainage system suitable for a compressed air energy storage cavern. During the construction and maintenance of the compressed air energy storage cavern, the pressure-maintaining drainage system of the present invention plays a drainage role and can achieve smooth drainage of the compressed air energy storage cavern. During the operation of the compressed air energy storage cavern, the pressure-maintaining drainage system of the present invention can make groundwater accumulate in the compressed air energy storage cavern structure outside the sealing layer, the surrounding rock around the compressed air energy storage cavern, and the pressure-maintaining drainage system, play a certain pressure-maintaining role, and contribute to the stability of structures such as the pressure-maintaining drainage system and the compressed air energy storage cavern.

[0012] (2) During the operation of the compressed air energy storage cavern, groundwater accumulated in the primary lining, secondary lining and surrounding rock around the compressed air energy storage cavern will hinder the further diffusion of high-pressure air in the compressed air energy storage cavern through the sealing layer. Compared with the case of no head pressure, the leakage of air in the compressed air energy storage cavern can be reduced, thereby further increasing the air tightness of the compressed air energy storage cavern;

[0013] (3) During the operation of the compressed air energy storage cavern, water accumulates inside the primary lining and the secondary lining, which can isolate the internal steel bars from contact with the air after the secondary lining cracks, thereby preventing the steel bars from rusting, which is beneficial to improving the corrosion resistance and structural stability of the compressed air energy storage cavern. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the effect of the pressure-maintaining drainage system after construction in the underground surrounding rock in the embodiment;

[0015] Figure 2 for Figure 2 The enlarged image of the dotted box in center A;

[0016] Figure 3 for Figure 1 The enlarged image of the dotted box in middle B;

[0017] The specific reference numerals in the figure are as follows:

[0018] 1-primary lining, 2-secondary lining, 3-sealing layer, 4-drainage blind pipe, 5-annular drainage pipe, 6-precast reinforced concrete pipe, 7-plug water pipe, 8-drainage valve, 9-underground water reservoir, 10-water pump, 11-outlet pipe, 12-maintenance passage, 13-underground surrounding rock, 14-vertical shaft. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the embodiments of the drawings. The devices, equipment or components not limited in the present invention all adopt conventional technical means in the art.

[0020] Embodiment: A pressure-maintaining drainage system suitable for compressed air energy storage caverns, such as Figure 1 to Figure 3 As shown, the compressed air energy storage cavern is arranged in the underground surrounding rock 13, and the compressed air energy storage cavern includes a primary lining 1, a secondary lining 2 and a sealing layer 3, and the sealing layer 3 is closely attached to the inner surface of the secondary lining 2. A vertical shaft 14 directly connected to the surface is arranged on one side of the compressed air energy storage cavern, and an underground water storage tank 9 is isolated at the bottom of the vertical shaft 14. The pressure-maintaining drainage system includes a prefabricated reinforced concrete pipe 6 arranged inside the compressed air energy storage cavern, a row of annular drainage pipes 5, several drainage blind pipes 4, and a plug water pipe 7 arranged outside the compressed air energy storage cavern, an underground water storage tank 9, an electrically controlled drainage valve 8, a water pump 10 and a water outlet pipe 11. The prefabricated reinforced concrete pipe 6 is arranged along the axial direction of the bottom of the compressed air energy storage cavern, and the prefabricated reinforced concrete pipe 6 is located between the secondary lining 2 and the primary lining 1, and the annular drainage pipe 5 is arranged at the bottom of the compressed air energy storage cavern. The drainage pipes 5 are distributed at intervals of 4m along the axial direction of the compressed air energy storage cavern. Each ring of annular drainage pipes 5 is located between the secondary lining 2 and the primary lining 1. The bottom of each ring of annular drainage pipes 5 is connected to the prefabricated reinforced concrete pipe 6. Each ring of annular drainage pipes 5 is connected to a plurality of drainage blind pipes 4. Each drainage blind pipe 4 penetrates and is buried in the primary lining 1. One end of the plug water pipe 7 is connected to the prefabricated reinforced concrete pipe 6. The other end of the plug water pipe 7 extends vertically into the underground water reservoir 9 and is equipped with a drainage valve 8. A water pump 10 is arranged at the bottom of the underground water reservoir 9. The water pump 10 is connected to the outlet pipe 11. The outlet pipe 11 extends to the surface. An inspection channel 12 is arranged on one side of the vertical shaft 14. The bottom of the inspection channel 12 leads to the compressed air energy storage cavern. The plug water pipe 7 is located below the inspection channel 12.

[0021] During the construction of the compressed air energy storage cavern, the drainage valve 8 is opened, and the groundwater in the underground surrounding rock 13 that penetrates into the compressed air energy storage cavern enters a row of annular drainage pipes 5 through several drainage blind pipes 4 and merges into the prefabricated reinforced concrete pipe 6, and then flows into the underground water reservoir 9 along the prefabricated reinforced concrete pipe 6 and the plug water pipe 7 under the action of gravity, and is finally discharged to the surface through the water pump 10 and the outlet pipe 11, thereby playing a drainage role and preventing groundwater from penetrating into the inside of the cavern and affecting the construction.

[0022] During the operation of the compressed air energy storage cavern, the compressed air energy storage cavern is in a state of high internal pressure. During the operation of the compressed air energy storage cavern, the drainage valve 8 is closed, and the groundwater that penetrates from the underground surrounding rock 13 into the primary lining 1 and the secondary lining 2 cannot be discharged. It will gradually accumulate in the primary lining 1, the secondary lining 2, the drainage blind pipe 4, the annular drainage pipe 5, the prefabricated reinforced concrete pipe 6, the plug water pipe 7 and the surrounding rock around the compressed air energy storage cavern outside the sealing layer 3 and generate a certain head pressure. The head pressure acts as an external pressure to offset part of the internal pressure of the compressed air energy storage cavern, thereby playing a certain pressure-maintaining role, which is beneficial to the stability of structures such as the pressure-maintaining drainage system and the compressed air energy storage cavern. In addition, the groundwater accumulated in the primary lining 1, the secondary lining 2 and the surrounding rock around the compressed air energy storage cavern will hinder the further outward diffusion of the high-pressure air in the compressed air energy storage cavern through the sealing layer 3. Compared with the absence of head pressure, the leakage of air in the compressed air energy storage cavern can be reduced, thereby further increasing the air tightness of the compressed air energy storage cavern. In addition, since water accumulates inside the primary lining 1 and the secondary lining 2, it can isolate the internal steel bars from contact with the air after the secondary lining 2 cracks, thereby preventing the steel bars from rusting, which is beneficial to improving the corrosion resistance and structural stability of the compressed air energy storage cavern.

[0023] During the maintenance of the compressed air energy storage cavern, the drainage valve 8 is opened, and the groundwater accumulated in the primary lining 1, the secondary lining 2, the drainage blind pipe 4, the annular drainage pipe 5, the prefabricated reinforced concrete pipe 6, the plug water pipe 7 outside the sealing layer 3 and the surrounding rock around the compressed air energy storage cavern is collected into the underground water tank 9 at the bottom of the shaft 14, and finally discharged to the surface through the water pump 10 and the outlet pipe 11, which can ensure that no groundwater will seep into the compressed air energy storage cavern after the gas is deflated.

Claims

1. A pressure-maintaining drainage system suitable for a compressed air energy storage cavern, wherein the compressed air energy storage cavern is arranged in an underground surrounding rock, the compressed air energy storage cavern comprises a primary lining, a secondary lining and a sealing layer, the sealing layer is closely attached to the inner surface of the secondary lining, a vertical shaft directly connected to the surface is arranged on one side of the compressed air energy storage cavern, and an underground water reservoir is isolated at the bottom of the vertical shaft, characterized in that: The pressure-maintaining drainage system comprises a prefabricated reinforced concrete pipe arranged inside the compressed air energy storage cavern, a row of annular drainage pipes, several drainage blind pipes, a plugged water pipe arranged outside the compressed air energy storage cavern, an underground water reservoir, an electrically controlled drainage valve, a water pump and a water outlet pipe, wherein the prefabricated reinforced concrete pipe is arranged axially along the bottom of the compressed air energy storage cavern, the prefabricated reinforced concrete pipe is located between the secondary lining and the primary lining, the annular drainage pipe is distributed at intervals along the axial direction of the compressed air energy storage cavern, and the annular drainage pipe of each ring is arranged at intervals. Between the secondary lining and the primary lining, the bottom of each ring of the annular drainage pipe is connected to the prefabricated reinforced concrete pipe, each ring of the annular drainage pipe is connected to a plurality of drainage blind pipes, each of the drainage blind pipes penetrates and is buried in the primary lining, one end of the plug water pipe is connected to the prefabricated reinforced concrete pipe, the other end of the plug water pipe vertically extends into the underground water reservoir and is installed with the drainage valve, the water pump is arranged at the bottom of the underground water reservoir, the water pump is connected to the water outlet pipe, and the water outlet pipe extends to the ground surface; During the construction and maintenance of the compressed air energy storage cavern, the drainage valve is opened, and the groundwater infiltrated in the underground surrounding rock enters the row of annular drainage pipes through the several drainage blind pipes and merges into the prefabricated reinforced concrete pipes, and then flows into the underground water storage tank along the prefabricated reinforced concrete pipes and the plug water pipes under the action of gravity, and finally is discharged to the surface through the pump and the outlet pipe, thereby playing a drainage role; During the operation of the compressed air energy storage cavern, the drainage valve is closed, and the groundwater that penetrates into the primary lining and the secondary lining from the underground surrounding rock cannot be discharged. It will gradually accumulate in the primary lining, the secondary lining, the drainage blind pipe, the annular drainage pipe, the prefabricated reinforced concrete pipe, the plug water pipe and the surrounding rock around the compressed air energy storage cavern outside the sealing layer and generate a certain head pressure. The head pressure acts as an external pressure to offset part of the internal pressure of the compressed air energy storage cavern, thereby playing a certain pressure-maintaining role, which is beneficial to improving the air tightness, corrosion resistance and structural stability of the compressed air energy storage cavern.

2. The pressure-maintaining drainage system suitable for compressed air energy storage caverns according to claim 1 is characterized in that: A maintenance passage is arranged on one side of the vertical shaft, the bottom of which leads to the compressed air energy storage cavern, and the plug water pipe is located below the maintenance passage.

3. The pressure-maintaining drainage system suitable for compressed air energy storage caverns according to claim 1 is characterized in that: Along the axial direction of the compressed air energy storage cavern, the spacing between two adjacent rings of annular drainage pipes is 3 to 5 meters.

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