Underground lining chamber composite lining crack observation method and concrete lining

Abstract

The invention provides an underground lining chamber composite lining crack observation method and a concrete lining, and relates to the technical field of underground lining chambers. The underground lining chamber composite lining crack observation method comprises the following steps that a high-permeability modified epoxy resin grouting material is injected into a glue injection pipeline; and the injection is kept during the curing period of the high-permeability modified epoxy resin grouting material. According to the method for observing the composite lining crack of the underground lining chamber, the underground lining chamber is simulated on the rock, and the development condition of the concrete crack in the pressure state is observed; after the resin is injected and cured, the expansion form of the crack is reserved, and the crack is not closed due to external force unloading, so that the actual expansion condition of the crack is completely recorded, and the stress and strain characteristics of the structure in the actual loading and unloading process are favorably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of underground lining chambers, in particular to a method for observing cracks in a composite lining of an underground lining chamber and a concrete lining. Background Art

[0002] Underground lined cavern gas storage will be deeply integrated with new technologies and applications such as gas-to-electricity conversion, hydrogen and helium storage, compressed gas energy storage, and large-scale CO2 storage. Several countries have already implemented lined caverns for hydrogen or natural gas storage. Sweden was the first to use artificially lined caverns for high-pressure natural gas storage. Subsequently, Japan and South Korea applied this technology to compressed gas energy storage caverns, experimenting with using polymer materials instead of steel linings as sealing layers. While most domestic research on reservoirs focuses on salt rock storage, lined cavern research primarily serves compressed gas energy storage projects.

[0003] However, for underground lining cavern composite linings, especially for crack observation of composite linings, there are currently two major technical difficulties:

[0004] (1) The composite lining structure is greatly disturbed by other structural layers, and conventional ultrasonic measurement is difficult to accurately measure the development of cracks (CN117011280A, CN117269312A).

[0005] (2) The closure of composite lining cracks after pressure unloading obscures the crack development pattern, making it more difficult to judge the crack behavior and affecting the subsequent analysis and judgment of the structural health. This is particularly evident under on-site cavern conditions. The above difficulties result in shortcomings such as insufficient accuracy and limited observation range in the observation of composite lining cracks in underground lined caverns. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for observing cracks in the composite lining of an underground lined chamber and a concrete lining, so as to alleviate the technical problem that the closing phenomenon of composite lining cracks after pressure unloading will cover up the development law of the cracks, increase the difficulty of judging the crack behavior, and affect the subsequent analysis and judgment of the structural health.

[0007] The present invention provides a method for observing cracks in a composite lining of an underground lining chamber, comprising the following steps:

[0008] S1. Drilling a hole in the rock mass to form a casting hole, placing a steel lining, a steel mesh, and a glue injection pipe in the casting hole, and pouring concrete between the outer wall of the steel lining and the inner wall of the casting hole to form a concrete layer;

[0009] S2. Injecting high-permeability modified epoxy resin grouting material into the glue injection pipe and maintaining the injection during the curing period of the high-permeability modified epoxy resin grouting material;

[0010] S3. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

[0011] In an optional embodiment, in S1, gas is injected into the steel lining and the pressure is maintained; in S2, a high-permeability modified epoxy resin grouting material is injected into the glue injection pipe using an air pump, and the pressure of the air pump is not less than 3 MPa.

[0012] The method for observing cracks in composite linings of underground chambers, provided by this invention, simulates an underground chamber on rock to observe the development of concrete cracks under pressure. After resin injection and curing, the crack propagation morphology is preserved and does not close due to external unloading. This allows for a complete record of the actual crack propagation, helping to restore the stress and strain characteristics of the structure during actual loading and unloading processes.

[0013] The present invention provides a method for observing cracks in a composite lining of an underground lining chamber, comprising the following steps:

[0014] S1. Place the steel lining, steel mesh and glue injection pipe into the mold and pour concrete, then demould to obtain the concrete lining;

[0015] S2. Drilling holes in the rock mass to form casting holes, assembling the concrete lining into the casting holes, and using mortar to seal the concrete lining;

[0016] S3, injecting high-permeability modified epoxy resin grouting material into the glue injection pipe, and maintaining the injection during the curing period of the high-permeability modified epoxy resin grouting material;

[0017] S4. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

[0018] The method for observing cracks in composite linings of underground chambers, provided by this invention, simulates an underground chamber on rock to observe the development of concrete cracks under pressure. After resin injection and curing, the crack propagation morphology is preserved and does not close due to external unloading. This allows for a complete record of the actual crack propagation, helping to restore the stress and strain characteristics of the structure during actual loading and unloading processes.

[0019] The present invention provides a concrete lining, comprising a steel lining and a concrete layer sleeved outside the steel lining; a steel mesh and a glue injection pipe are pre-embedded in the concrete layer; the steel mesh and the glue injection pipe are both arranged around the steel lining; and the glue injection pipe surrounds the outside of the steel mesh.

[0020] In an optional embodiment, a plurality of grouting holes are provided on the glue injection pipe, and the hole distance between two adjacent grouting holes is 5 cm-20 cm.

[0021] In an optional embodiment, the glue injection pipe is arranged on the steel liner in multiple circles, and 25-30 grouting holes are provided on each circle of the glue injection pipe.

[0022] In an optional embodiment, the thickness of the steel lining is 5 mm-16 mm, and the radius of the steel lining is less than or equal to 20 cm.

[0023] In an optional embodiment, the distance between the steel mesh and the steel lining is between 1 cm and 10 cm.

[0024] In an optional embodiment, the outer diameter of the glue injection pipe is less than one tenth of the thickness of the concrete layer.

[0025] In an optional embodiment, the glue injection pipe is spaced apart from the outer side wall of the concrete layer by 1 cm to 10 cm.

[0026] The concrete lining provided by the present invention can simulate the development of concrete cracks in the composite lining of an underground lining chamber under pressure on rock, which helps to restore the stress and strain characteristics of the structure during actual loading and unloading, and then propose corresponding construction methods to ensure the safety and reliability of the underground lining chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of a method for observing composite lining cracks in an underground lining chamber provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of another method for observing cracks in the composite lining of an underground lined chamber provided in an embodiment of the present invention.

[0030] Figure 3 A schematic structural diagram of a concrete lining in use according to an embodiment of the present invention;

[0031] Figure 4 for Figure 3 The structural diagram of the concrete lining in use state is shown as a schematic diagram of the rock structure.

[0032] Icons: 100-rock mass; 200-casting hole; 300-steel lining; 400-steel mesh; 500-glue injection pipe; 600-concrete layer. DETAILED DESCRIPTION

[0033] The terms "first", "second", "third", etc. are only used to distinguish and describe, and do not indicate the order of arrangement, nor can they be understood as indicating or implying relative importance.

[0034] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0035] In the description of this application, it should be noted that the terms "inside", "outside", "left", "right", "up", "down", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0036] In the description of this application, unless otherwise clearly specified and limited, the terms "set", "install", "connected" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the internal parts of two elements.

[0037] The technical solution of this application will be clearly and completely described below with reference to the accompanying drawings.

[0038] Example

[0039] Reference Figure 1 The present invention provides a method for observing cracks in a composite lining of an underground lining chamber, comprising the following steps:

[0040] S1. Drilling a hole in the rock mass 100 to form a casting hole 200, placing a steel liner 300, a steel mesh 400, and a glue injection pipe 500 in the casting hole 200, and pouring concrete between the outer wall of the steel liner 300 and the inner wall of the casting hole 200 to form a concrete layer 600;

[0041] S2, injecting high-permeability modified epoxy resin grouting material into the glue injection pipe 500, and keeping injecting the high-permeability modified epoxy resin grouting material during the curing period;

[0042] S3. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

[0043] In an optional embodiment, in S1, gas is injected into the steel lining 300 and the pressure is maintained; in S2, a high permeability modified epoxy resin grouting material is injected into the glue injection pipe 500 using an air pump, and the pressure of the air pump is not less than 3 MPa.

[0044] The method for observing cracks in composite linings of underground chambers, provided by this invention, simulates an underground chamber on rock to observe the development of concrete cracks under pressure. After resin injection and curing, the crack propagation morphology is preserved and does not close due to external unloading. This allows for a complete record of the actual crack propagation, helping to restore the stress and strain characteristics of the structure during actual loading and unloading processes.

[0045] In some embodiments, a hole is drilled in the rock mass 100 to form a casting hole 200, and the size of the casting hole 200 is designed in a certain proportion to the actual underground lining chamber; a steel lining 300, a steel bar and a glue injection pipe 500 are assembled in the casting hole 200, and concrete is poured between the steel lining 300 and the inner wall of the casting hole 200.

[0046] After the concrete solidifies, the required pressure is loaded onto the steel lining 300 and maintained; the pressure is adjusted according to the pressure required by the underground lining chamber; while the steel lining 300 is under pressure, high-permeability modified epoxy resin grouting material is injected into the glue injection pipe 500, and the injection is maintained during the period when the high-permeability modified epoxy resin grouting material is solidified.

[0047] Since the steel lining 300 is in a state of pressure required to maintain the load, the cracks in the concrete layer 600 remain, and the high-permeability modified epoxy resin grouting material can flow into the cracks in the concrete layer 600; after the high-permeability modified epoxy resin grouting material solidifies, a cross-sectional scan is performed using a pressure radar probe to collect concrete cracking information.

[0048] The infiltration-modified epoxy resin filling material can fill the fine paths of the cracks in the concrete layer 600 and form a three-dimensional shape consistent with the cracks after curing, so that the paths of the cracks in any expansion state can be visually observed and can truly reflect geometric information such as crack depth, width and branching.

[0049] The strength of the high-permeability modified epoxy resin grouting material after curing can reach the C40 standard. At the same time, it can be cured within 30 minutes and the time to reach peak strength is 1 day.

[0050] Reference Figure 2 The present invention provides a method for observing cracks in a composite lining of an underground lining chamber, comprising the following steps:

[0051] S1, placing the steel lining 300, the steel mesh 400 and the glue injection pipe 500 into a mold and pouring concrete, then demoulding to obtain a concrete lining;

[0052] S2. Drilling a hole in the rock mass 100 to form a casting hole 200, assembling a concrete lining into the casting hole 200, and sealing the concrete lining with mortar;

[0053] S3, injecting high-permeability modified epoxy resin grouting material into the glue injection pipe 500, and keeping injecting the high-permeability modified epoxy resin grouting material during the curing period;

[0054] S4. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

[0055] In some embodiments, the steel lining 300, the steel mesh 400 and the glue injection pipe 500 are assembled in a mold and poured. After the concrete is solidified, a concrete lining is formed. After the mold is removed, the concrete lining is obtained.

[0056] The concrete lining is assembled into the casting hole 200. The steps of drilling a hole in the rock to form the casting hole 200 and casting the concrete lining are not in particular order; and the gap between the concrete lining and the rock is sealed with mortar.

[0057] A method for observing cracks in composite linings of underground lined chambers solves the difficulties in observing cracks in composite linings, and solves the problems that the closing phenomenon of concrete lining cracks after pressure unloading will mask the development law of cracks. It improves the accuracy of analysis and judgment of the health of composite lining structures of underground lined caverns, and can effectively improve the shortcomings of insufficient observation accuracy and limited observation range of composite lining cracks in underground lined caverns. It is of great significance to the fields of underground caverns, compressed gas energy storage, underground reservoirs, composite linings, etc.

[0058] Reference Figure 3 and Figure 4 The present invention provides a concrete lining, including a steel lining 300 and a concrete layer 600 sleeved on the outside of the steel lining 300; a steel mesh 400 and a glue injection pipe 500 are pre-embedded in the concrete layer 600; and the steel mesh 400 and the glue injection pipe 500 are both arranged around the steel lining 300; and the glue injection pipe 500 surrounds the outside of the steel mesh 400.

[0059] In an optional embodiment, the glue injection pipe 500 is provided with a plurality of grouting holes, and the hole spacing between two adjacent grouting holes is 5cm-20cm; the glue injection pipe 500 is arranged on the steel lining 300 in multiple circles, and each circle of the glue injection pipe 500 is provided with 25-30 grouting holes; the thickness of the steel lining 300 is 5mm-16mm, and the radius of the steel lining 300 is less than or equal to 20cm; the steel mesh 400 is spaced apart from the steel lining 300 by 1cm-10cm; the outer diameter of the glue injection pipe 500 is less than one tenth of the thickness of the concrete layer 600; the glue injection pipe 500 is spaced apart from the outer wall of the concrete layer 600 by 1cm-10cm.

[0060] The steel lining 300 is made of 310 stainless steel, and the glue injection pipe 500 is made of a flexible and soft copper pipe. The inner diameter of the copper pipe shall not exceed 1 / 10 of the overall thickness of the concrete.

[0061] Rocks can be selected according to the actual situation on site. Before conducting the test, the rock's compressive strength, elastic modulus, Poisson's ratio and other parameters can be calibrated through uniaxial compression tests.

[0062] Choose C30 concrete, and after forming it once, use 425 cement mortar to smooth the gap between it and the rock.

[0063] To simulate an underground lined chamber, according to actual use requirements, the steel lining 300 is filled with relevant gas and maintained at the design required pressure; the relevant gas can be hydrogen or natural gas, for example.

[0064] Typically, three loops of the glue injection pipe 500 are completed, and holes are drilled with a fine drill bit to serve as grouting holes. For concrete pouring, the coarse aggregate is typically approximately 2 cm in size, so the grouting holes should be 2 mm to 10 mm in diameter, with a spacing of 5 cm to 20 cm. Ensure that at least 30 holes are drilled in each loop of the glue injection pipe 500. The glue injection pipe 500 is continuous from front to back, with the middle section bent into three loops. The spacing between the three loops can be customized based on the cavern dimensions.

[0065] During the grouting process, the grouting holes of the injection pipes are sealed with plastic sheets to prevent the grouting holes from being blocked during pouring.

[0066] The pressure required by the air pump can be estimated based on factors such as resin viscosity, crack width, and cavity size. Generally, the air pump's pressurization capacity is not less than 3MPa.

[0067] Low-frequency radar is used to scan and monitor concrete cracking in the actual test cavern. The frequency of the low-frequency radar is between 4MHz and 10MHz, ensuring that it can penetrate the steel lining of the actual cavern 300 to detect concrete cracks. The low-frequency radar uses a titanium alloy shell and is equipped with a high-sealing rubber ring to ensure its stable operation in the cavern.

[0068] The concrete lining provided by the present invention can simulate the development of concrete cracks in the composite lining of an underground lining chamber under pressure on rock, which helps to restore the stress and strain characteristics of the structure during actual loading and unloading, and then propose corresponding construction methods to ensure the safety and reliability of the underground lining chamber.

[0069] Compared with the prior art, the advantages of the present invention are:

[0070] Maintaining crack expansion in situ: After the high-permeability modified epoxy resin grout is injected and cured, the crack's propagation morphology is preserved, preventing it from closing due to external unloading. This allows for a complete record of the actual crack growth, helping to restore the stress and strain characteristics of the structure during actual loading and unloading processes.

[0071] Clearly and intuitively present the crack path: High-permeability modified epoxy resin grouting material can fill the tiny crack paths and form a three-dimensional shape consistent with the crack after curing, so that the crack path in any expansion state can be intuitively observed, and can truly reflect the geometric information such as crack depth, width and branching.

[0072] Applicable to on-site underground lining caverns: High-permeability modified epoxy resin grouting injection technology is suitable for use in on-site underground lining caverns, allowing for easy crack filling and controlled resin flow through injection equipment. Compared to other observation techniques (such as speckle and ultrasonic), high-permeability modified epoxy resin grouting injection does not require complex sensor arrangements or large instrumentation, reducing experimental difficulty.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for observing cracks in composite linings of underground lining chambers, characterized in that: The following steps are involved: S1. Drilling a hole in the rock mass (100) to form a casting hole (200), placing a steel lining (300), a steel mesh (400), and a glue injection pipe (500) in the casting hole (200), and pouring concrete between the outer wall of the steel lining (300) and the inner wall of the casting hole (200) to form a concrete layer (600); S2, injecting high-permeability modified epoxy resin grouting material into the glue injection pipe (500), and keeping injecting the high-permeability modified epoxy resin grouting material during the curing period; S3. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

2. The method for observing cracks in composite linings of underground lining chambers according to claim 1, characterized in that: In S1, gas is injected into the steel lining (300) and the pressure is maintained; in S2, a high-permeability modified epoxy resin grouting material is injected into the glue injection pipe (500) using an air pump, and the pressure of the air pump is not less than 3 MPa.

3. A method for observing cracks in composite linings of underground lining chambers, characterized in that: The following steps are involved: S1, placing the steel lining (300), the steel mesh (400) and the glue injection pipe (500) into a mold and pouring concrete, and then demoulding to obtain a concrete lining; S2, drilling a hole in the rock mass (100) to form a casting hole (200), assembling a concrete lining into the casting hole (200), and sealing the concrete lining with mortar; S3, injecting high-permeability modified epoxy resin grouting material into the glue injection pipe (500), and keeping injecting the high-permeability modified epoxy resin grouting material during the curing period; S4. Slowly move the pressure-resistant radar probe to scan along the preset observation section to collect information on the development of concrete cracks.

4. A concrete lining, characterized in that: The invention comprises a steel lining (300) and a concrete layer (600) sleeved outside the steel lining (300); a steel mesh (400) and a glue injection pipe (500) are pre-buried in the concrete layer (600); the steel mesh (400) and the glue injection pipe (500) are both arranged around the steel lining (300); and the glue injection pipe (500) surrounds the outside of the steel mesh (400).

5. The concrete lining according to claim 4, characterized in that The glue injection pipe (500) is provided with a plurality of grouting holes, and the hole spacing between two adjacent grouting holes is 5 cm to 20 cm.

6. The concrete lining according to claim 5, characterized in that The glue injection pipe (500) is arranged on the steel liner (300) in multiple circles, and 25 to 30 grouting holes are arranged on each circle of the glue injection pipe (500).

7. The concrete lining according to claim 4, characterized in that The thickness of the steel lining (300) is 5 mm to 16 mm, and the radius of the steel lining (300) is less than or equal to 20 cm.

8. The concrete lining according to claim 4, characterized in that The distance between the steel mesh (400) and the steel lining (300) is between 1 cm and 10 cm.

9. The concrete lining according to claim 4, characterized in that The outer diameter of the glue injection pipe (500) is less than one tenth of the thickness of the concrete layer (600).

10. The concrete lining according to claim 4, characterized in that The distance between the glue injection pipe (500) and the outer wall of the concrete layer (600) is between 1 cm and 10 cm.

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