High-pressure tunnel sealing structure utilizing thermal expansion performance of concrete

Abstract

The invention belongs to the technical field of high-pressure tunnel sealing, and particularly discloses a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete, which comprises a thermal insulation layer, a restraint layer, a concrete thermal expansion layer and a sealing layer which are sequentially arranged from the excavation outline of a high-pressure tunnel to the interior of a chamber of the high-pressure tunnel. The concrete thermal expansion layer annularly and integrally generates compressive stress under the action of temperature load, tensile stress caused by outward expansion deformation under the action of partial internal pressure can be counteracted, then deformation of the sealing layer is reduced, the thickness of a steel plate can be reduced, the construction cost is reduced, meanwhile, construction is convenient, and the construction progress can be remarkably accelerated.

Description

Technical Field

[0001] The invention discloses a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete, belonging to the technical field of high-pressure tunnel sealing. Background Art

[0002] Compressed gas energy storage refers to a storage method that uses electricity to compress air during the low load period of the power grid, and releases compressed air to drive the steam turbine to generate electricity during the peak load period of the power grid. Compressed gas energy storage requires a large-scale sealed container to store high-pressure fluids. Underground rock tunnels have become the preferred choice due to their low construction cost and high safety.

[0003] The sealing of large-scale high-pressure tunnels for compressed gas energy storage determines the success or failure of the project. Currently, steel plates are generally used for sealing. The thickness of the steel plates is as high as several centimeters, the cost is high, and the installation process requirements are high, which brings great challenges to the project construction. Summary of the invention

[0004] The purpose of the present invention is to provide a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete, so as to solve the technical problems of slow construction progress and high engineering cost in the prior art using thick steel plate sealing.

[0005] The invention provides a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete, comprising a heat insulation layer, a constraint layer, a concrete thermal expansion layer and a sealing layer sequentially arranged from the excavation profile of the high-pressure tunnel to the interior of the chamber of the high-pressure tunnel.

[0006] Preferably, the average thermal expansion coefficient of the concrete thermal expansion layer is 10 -5 / ℃.

[0007] Preferably, the thickness of the concrete thermal expansion layer is greater than or equal to 50 cm.

[0008] Preferably, the concrete grade used in the concrete thermal expansion layer is greater than or equal to C30.

[0009] Preferably, it also includes a lining base; The lining base is arranged on the excavation profile of the high-pressure tunnel; The heat insulation layer is arranged on a side surface of the lining base layer away from the excavation contour.

[0010] Preferably, the thickness of the lining base layer is less than or equal to 20 cm.

[0011] Preferably, the heat insulation layer is an aluminized film or a PET film.

[0012] Preferably, the constraining layer comprises a plurality of steel arches sequentially arranged along the axis of the high-pressure tunnel.

[0013] Preferably, the spacing between adjacent steel arches is less than or equal to 1 m.

[0014] Compared with the prior art, the high-pressure tunnel sealing structure using the thermal expansion performance of concrete of the present invention has the following beneficial effects: Under the action of temperature load, the concrete thermal expansion layer of the present invention generates compressive stress in the hoop as a whole, which can offset the tensile stress caused by the outward expansion deformation under the action of part of the internal pressure, thereby reducing the deformation of the sealing layer, thereby reducing the thickness of the steel plate and reducing the project cost. At the same time, the construction is convenient and the construction progress can be significantly accelerated.

[0015] The present invention lays a heat insulation layer on the surface of the lining base, controls the temperature influence inside the chamber within the concrete thermal expansion layer, increases the thermal expansion effect of the concrete thermal expansion layer and reduces the influence of temperature on the lining base and surrounding rock, and also plays a role of secondary sealing.

[0016] The present invention lays an insulation layer on the surface of the lining base and arranges a constraint layer composed of a series of steel arches according to the surrounding rock type, which can effectively increase the external constraint effect of the concrete thermal expansion layer, thereby ensuring that the concrete thermal expansion layer deforms toward the inside of the chamber during thermal expansion.

[0017] The concrete of the concrete thermal expansion layer of the present invention adopts expansion cement or is mixed with expansion agent, which can generate chemical prestress inside the concrete, thereby improving the crack resistance of the concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete according to an embodiment of the present invention.

[0019] Figure 2 It is the deformation diagram of the concrete and surrounding rock (elastic modulus 10 GPa) of a high-pressure tunnel chamber with an inner diameter of 10 m under the action of an internal pressure of 10 MPa in an embodiment of the present invention.

[0020] In the figure: 1. Excavation outline; 2. Lining base; 3. Concrete thermal expansion layer; 4. Constraint layer; 5. Sealing layer; 6. Insulation layer; 7. Chamber interior. DETAILED DESCRIPTION

[0021] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0022] The embodiment of the present invention provides a high-pressure tunnel sealing structure utilizing the thermal expansion performance of concrete, such as Figure 1 As shown, it includes a heat insulation layer 6, a constraint layer 4, a concrete thermal expansion layer 3 and a sealing layer 5 which are arranged in sequence from the excavation profile 1 of the high-pressure tunnel to the interior 7 of the chamber of the high-pressure tunnel.

[0023] In the compressed air energy storage underground high-pressure tunnel, the temperature in the air compression tunnel will increase accordingly, and the local temperature rise may reach 100°C. The present invention uses the influence of this temperature on the concrete thermal expansion layer 3 to offset part of the internal pressure of the high-pressure tunnel, thereby reducing the requirements for the sealing layer 5 and ensuring the sealing performance of the high-pressure tunnel.

[0024] The function of the above-mentioned thermal insulation layer 6 is to isolate the temperature inside the chamber 7, that is, only the concrete thermal expansion layer 3 undergoes thermal expansion, while the surrounding rock outside the thermal insulation layer 6 is not affected by the temperature, so as to avoid the surrounding rock from changing its physical and chemical properties due to temperature changes, thereby affecting its stability. In addition, the function of the thermal insulation layer 6 can cause the temperature to be mainly applied to the concrete thermal expansion layer 3, thereby facilitating the expansion of the concrete thermal expansion layer 3, so that part of the internal pressure of the high-pressure tunnel is offset during the expansion process to the inside of the chamber 7, thereby reducing the requirements for the sealing layer 5 and ensuring the sealing performance of the high-pressure tunnel. The thermal insulation layer 6 in the embodiment of the present invention can also play a secondary sealing role.

[0025] In the embodiment of the present invention, the material of the heat insulation layer 6 can be an aluminum-plated film or a PET film with excellent heat insulation performance.

[0026] The function of the above-mentioned constraint layer 4 is to constrain and limit the expansion direction of the concrete thermal expansion layer 3, so that the concrete thermal expansion layer 3 expands toward the interior 7 of the chamber, thereby offsetting part of the internal pressure to the greatest extent and reducing its impact on the surrounding rock, thereby avoiding affecting the stability of the surrounding rock.

[0027] In the embodiment of the present invention, the constraint layer 4 includes a plurality of steel arch frames arranged in sequence along the axis of the high-pressure tunnel, wherein the spacing between the plurality of steel arch frames is arranged according to the type of surrounding rock, and the spacing between adjacent steel arch frames is less than or equal to 1m. The present invention uses steel arch frames as the constraint layer 4, which can significantly increase the external constraint stiffness of the concrete thermal expansion layer 3, ensure the constraint and limiting effect, and the steel arch frames are prefabricated assembly structures, therefore, they can be quickly assembled at the construction site to speed up the construction progress. In order to minimize the requirements for the sealing layer 5, the initial thickness of the concrete thermal expansion layer 3 used in the embodiment of the present invention is greater than or equal to 50 cm, and the average thermal expansion coefficient of the concrete thermal expansion layer 3 is 10 -5 / °C. At the same time, since the concrete thermal expansion layer 3 plays the role of lining, in order to ensure its compressive strength, the concrete grade used in the concrete thermal expansion layer 3 of the embodiment of the present invention is greater than or equal to C30.

[0028] The concrete used in the concrete thermal expansion layer 3 of the embodiment of the present invention needs to be mixed with an expansion agent. The method of adding the expansion agent can be to use expansion cement or to add the expansion agent to the concrete using ordinary cement. The amount of the expansion agent added only needs to meet the average thermal expansion coefficient of the concrete thermal expansion layer 3 of 10 -5 The expansion agent used in the present invention can also generate chemical prestress inside the concrete, improve its crack resistance, and further ensure the sealing of the high-pressure tunnel.

[0029] In order to protect the main body and internal space of the high-pressure tunnel from erosion and damage caused by external factors such as moisture, soil pressure, external wear, etc., the embodiment of the present invention further includes a lining base 2; the lining base 2 is arranged on the excavation profile 1 of the high-pressure tunnel; correspondingly, the heat insulation layer 6 is arranged on the side surface of the lining base 2 away from the excavation profile 1. The thickness of the lining base 2 is less than or equal to 20 cm. In addition to protecting the main body and internal space of the high-pressure tunnel, the lining base 2 of the embodiment of the present invention also has the function of increasing the durability and stability of the high-pressure tunnel.

[0030] The construction method of the high-pressure tunnel sealing structure using the thermal expansion performance of concrete is as follows: first, the chamber is excavated by drilling and blasting method. The excavation surface is irregular. Therefore, a layer of backfill concrete not more than 20 cm is poured as the lining base 2 on the basis of ensuring the stability of the surrounding rock; after the backfill concrete is poured, the insulation layer 6 and the constraint layer 4 are constructed; after the insulation layer 6 and the constraint layer 4 are constructed, the concrete thermal expansion layer 3 is cast in situ as a whole, with a thickness of not less than 50 cm and a grade of not less than C30. Expansive cement or an expansion agent is used to generate chemical prestress inside the concrete to improve its crack resistance; the average thermal expansion coefficient of the concrete is 10 -5 / ℃; finally, a sealing layer 5 is arranged on the concrete thermal expansion layer 3. The sealing layer 5 can be a flexible sealing layer or a steel plate can be used as the sealing layer. For example, after making full use of the thermal expansion performance of concrete, when the material of the sealing layer 5 of the interior 7 of the chamber is a steel plate, its thickness can be significantly reduced and only has to play a sealing role.

[0031] The test shows that for a high-pressure tunnel with a diameter of 10m, when the average temperature rises by 50°C, the radial deformation of the concrete thermal expansion layer 3 of the present invention reaches 2.5mm; Figure 2 It can be seen from the figure that when the elastic modulus of the surrounding rock is 10 GPa, the chamber of a high-pressure tunnel with a diameter of 10 m deforms by about 5.15 mm under an internal pressure of 10 MPa. If the structure of the present invention is adopted, the deformation of 2.5 mm can be offset, which is beneficial to the deformation control of the interior of the chamber 7.

[0032] The present invention lays a heat insulation layer 6 on the surface of the lining base 2, controls the temperature influence of the interior 7 of the chamber within the concrete thermal expansion layer 3, increases the thermal expansion effect of the concrete thermal expansion layer 3 and reduces the influence of temperature on the lining base 2 and the surrounding rock, and also plays a role of secondary sealing.

[0033] The present invention lays the heat insulation layer 6 on the surface of the lining base 2 and arranges a series of constraint layers composed of steel arches according to the surrounding rock type, which can effectively increase the external constraint effect of the concrete thermal expansion layer 3, thereby ensuring that the concrete thermal expansion layer 3 deforms toward the interior 7 of the chamber during thermal expansion.

[0034] The concrete of the concrete thermal expansion layer 3 of the present invention uses expansion cement or is mixed with an expansion agent, which can generate chemical prestress inside the concrete, thereby improving its crack resistance.

[0035] The concrete thermal expansion layer 3 of the present invention is cast in place as a whole. Under the action of temperature load, compressive stress is generated in the circumferential direction as a whole, which can offset the tensile stress caused by the outward expansion deformation under the action of part of the internal pressure, thereby reducing the deformation of the sealing layer 5, thereby reducing the thickness of the steel plate and the project cost. At the same time, the construction is convenient and can significantly speed up the construction progress.

[0036] The above are only several embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, using the above disclosed technical content to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A high-pressure tunnel sealing structure utilizing the thermal expansion properties of concrete, characterized in that: The invention comprises a heat-insulating layer, a restraining layer, a concrete heat-expansion layer and a sealing layer which are sequentially arranged from the excavation outline of the high-pressure tunnel to the interior of the chamber of the high-pressure tunnel.

2. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 1 is characterized in that: The average thermal expansion coefficient of the concrete thermal expansion layer is 10 -5 / ℃.

3. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 2 is characterized in that: The thickness of the concrete thermal expansion layer is greater than or equal to 50 cm.

4. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 2 or 3, characterized in that: The concrete grade used in the concrete thermal expansion layer is greater than or equal to C30.

5. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 1, characterized in that: It also includes lining base; The lining base is arranged on the excavation profile of the high-pressure tunnel; The heat insulation layer is arranged on a side surface of the lining base layer away from the excavation contour.

6. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 5, characterized in that: The thickness of the lining base layer is less than or equal to 20 cm.

7. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 1, characterized in that: The heat insulation layer is an aluminum-plated film or a PET film.

8. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 1, characterized in that: The constrained layer includes a plurality of steel arches arranged in sequence along the axis of the high-pressure tunnel.

9. The high-pressure tunnel sealing structure using the thermal expansion performance of concrete according to claim 8, characterized in that: The spacing between adjacent steel arches is less than or equal to 1m.

Images