A loading device and method for simulating actual stress conditions of a tunnel lining

Abstract

The application discloses a loading device for simulating actual stress conditions of tunnel lining, which comprises a counterforce frame and a lining component. The lining component is arc-shaped. The counterforce frame comprises counterforce frame cross beams and counterforce frame vertical beams. Two counterforce frame cross beams and two counterforce frame vertical beams are arranged respectively. The two counterforce frame vertical beams are placed in parallel at a certain distance apart. The two counterforce frame cross beams are connected. The lining component is located inside the counterforce frame. One end of the lining component is a fixed end, and the other end is a loading end. The fixed end is provided with a fixed end gasket. The loading end is provided with a loading end gasket. A jack is arranged between the loading end gasket and the loading end. The application further discloses a use method of the loading device for simulating actual stress conditions of tunnel lining. The loading device for simulating actual stress conditions of tunnel lining is adopted, so that the problem that the existing loading form of the tunnel lining component simulation cannot well reflect the actual stress conditions of the tunnel lining is solved.

Description

Technical Field

[0001] This invention relates to the field of defect treatment technology in tunnel engineering, and in particular to a loading device and its method of use for simulating the actual stress conditions of tunnel lining. Background Technology

[0002] Since the beginning of the 21st century, China's railway tunnel engineering has developed rapidly. With the construction of high-speed railways and intercity railways, railway tunnels are characterized by high construction standards, long lengths, large cross-sections, and complex geology. Due to limitations in construction technology and geological conditions, many early-built tunnels often suffer from defects such as insufficient lining thickness, backfill voids, lining cracks, and spalling. After a certain period of service, the linings of many completed tunnels also gradually deteriorate, leading to a series of defects.

[0003] Treatment measures for defects and malfunctions in tunnel lining include grouting and backfilling, bolt reinforcement, reinforcement of the inner surface of the lining, and reinforcement with FRP materials. These measures fully utilize the support potential of the existing lining and reinforce the tunnel lining structure when the overall self-stabilizing capacity of the tunnel structure is strong, thereby improving the stress condition of the tunnel lining structure and ensuring tunnel safety.

[0004] Before applying the aforementioned repair and reinforcement measures for tunnel lining defects to actual engineering projects, corresponding component tests are required to determine their safety. Existing tunnel lining component tests generally use corbel components to load from both sides or curved lining components to load from the circumferential to the back side. When tunnel linings are actually in service, they are subjected to pressure. The existing loading method of constraining the two ends of the lining components and loading from the circumferential to the back side of the component cannot well reflect the actual stress condition of the tunnel lining. Summary of the Invention

[0005] The purpose of this invention is to provide a loading device for simulating the actual stress conditions of tunnel lining, solving the problem that existing loading methods for simulating tunnel lining components cannot accurately reflect the actual stress conditions of tunnel lining. Another purpose of this invention is to provide a method for using the loading device for simulating the actual stress conditions of tunnel lining.

[0006] To achieve the above objectives, the present invention provides a loading device for simulating the actual stress conditions of tunnel lining, comprising a reaction frame and a lining component. The lining component is arc-shaped. The reaction frame includes two reaction frame horizontal beams and two reaction frame vertical beams. Two reaction frame horizontal beams and two reaction frame vertical beams are provided. The two reaction frame vertical beams are placed parallel to each other at a certain distance and connected by two reaction frame horizontal beams. The lining component is located inside the reaction frame. One end of the lining component is a fixed end and the other end is a loading end. The fixed end is provided with a fixed end shim, and the loading end is provided with a loading end shim. A jack is provided between the loading end shim and the loading end.

[0007] Preferably, one side of the fixed end gasket is inclined and maintains the same inclination as the fixed end, while the other side is connected to the reaction frame vertical beam near the fixed end.

[0008] Preferably, one side of the loading end pad is inclined and maintains the same inclination as the loading end, while the other side is connected to the reaction frame vertical beam near the loading end.

[0009] Preferably, the back of the jack is placed close to the loading end pad, and a steel plate is provided between the top of the jack and the side of the lining component, and the steel plates are connected by a hinge.

[0010] Preferably, the back of the lining component is provided with a plurality of uniformly distributed hard rubber pads, the hard rubber pads are connected to the I-beams, and the I-beams are provided with inclined supports arranged circumferentially along the curvature of the lining component above the inclined supports, which are welded to the reaction frame beams.

[0011] The method of using the above-mentioned loading device for simulating the actual stress condition of tunnel lining includes the following steps:

[0012] S1. Place two vertical reaction frame beams parallel to each other at a certain distance in the vertical direction, and connect them in the middle with two horizontal reaction frame beams. Weld them to the joint of the horizontal reaction frame beams at a certain distance inside the end of the vertical reaction frame beams to complete the installation of the reaction frame.

[0013] S2. Determine the inclination angles of the loading end shim and the fixed end shim according to the inclination angles of the left and right sides of the lining component. After the loading end shim and the fixed end shim are made, weld them to the corresponding positions on the reaction frame.

[0014] S3. Place one side of the lining component tightly against the fixed end shim, and place the back of the jack tightly against the loading end shim. The lateral length of the loading end shim needs to be calculated in advance to ensure that after placing the lining component and the jack, a steel plate is placed between the top of the jack and the side of the lining component.

[0015] S4. Several hard rubber pads are evenly arranged on the back side of the lining component. I-beams are connected to the rubber pads. Inclined supports are set in the circumferential direction according to the curvature of the lining component. The I-beams are welded to the inclined supports. The inclined supports are welded to the reaction frame beam. The load is applied to the lining component by a jack oil pump truck.

[0016] The advantages and positive effects of the loading device and its method for simulating the actual stress condition of tunnel lining described in this invention are as follows:

[0017] This invention expands the loading methods for tunnel component testing. By setting a hard rubber pad on the back side of the lining component, as well as an I-beam and an inclined support, it simulates the surrounding rock resistance of the actual tunnel lining. By setting a shim at the loading end to adjust the angle of the jack, it ensures that the jack can apply the load perpendicular to the loading end section of the lining component, thereby simulating the actual stress on the secondary lining component of the tunnel.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a loading device for simulating the actual stress conditions of tunnel lining according to the present invention.

[0020] Figure 2 This is a schematic diagram of an inclined support in a loading device for simulating the actual stress conditions of a tunnel lining according to the present invention.

[0021] Figure 3 This is a schematic diagram of the inclination angle of the loading end gasket and the fixed end gasket, and the cross-sectional arrangement of the lining components in a loading device for simulating the actual stress condition of tunnel lining according to the present invention.

[0022] Figure 4 This is a schematic diagram of the jack in a loading device for simulating the actual stress conditions of a tunnel lining according to the present invention.

[0023] Figure Labels

[0024] 1. Reaction frame crossbeam; 2. Reaction frame vertical beam; 3. Inclined support; 4. I-beam; 5. Hard rubber pad; 6. Lining component; 7. Steel plate; 8. Hinged component; 9. Jack; 10. Loading end gasket; 11. Fixed end gasket. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Example

[0028] A loading device simulating the actual stress condition of tunnel lining includes a reaction frame and a lining component 6. The lining component 6 is arc-shaped. The reaction frame includes a reaction frame crossbeam 1 and a reaction frame vertical beam 2. There are two reaction frame crossbeams 1 and two reaction frame vertical beams 2. The two reaction frame vertical beams 2 are placed parallel to each other at a certain distance and connected by two reaction frame crossbeams 1. The lining component 6 is located inside the reaction frame. One end of the lining component 6 is a fixed end and the other end is a loading end. The fixed end is provided with a fixed end shim 11, and the loading end is provided with a loading end shim 10. A jack 9 is provided between the loading end shim 10 and the loading end.

[0029] The entire loading device consists of components such as reaction frame crossbeam 1, reaction frame vertical beam 2, loading end gasket 10, fixed end gasket 11, inclined support 3, hard rubber pad 5, jack 9, I-beam 4, steel plate 7, hinge 8, and lining component 6. Before arranging the specific component positions, the installation and welding of reaction frame crossbeam 1 and reaction frame vertical beam 2 must be completed.

[0030] One side of the fixed-end shim 11 is inclined and maintains the same inclination as the fixed end, while the other side is connected to the reaction frame vertical beam 2 near the fixed end. One side of the loading-end shim 10 is inclined and maintains the same inclination as the loading end, while the other side is connected to the reaction frame vertical beam 2 near the loading end.

[0031] The inclination angles of both the loading end shim 10 and the fixed end shim 11 must be consistent with the inclination angle of the corresponding section of the lining member 6. The section of the fixed end shim 11 must be tightly attached to the fixed end section of the lining member 6 to ensure that stress concentration does not occur at the end, thus affecting the test results. The loading end shim 10 is designed to have a section that can tightly attach to the side of the loading end of the lining member 6. Figure 3As shown, although the two end loads do not come into direct contact, they must maintain a shape fit. The other side of the load end gasket 10 and the fixed end gasket 11 are welded to the reaction frame vertical beam 2 respectively.

[0032] The jack 9 is placed with its back side tightly against the loading end pad 10. A steel plate 7 is installed between the top of the jack 9 and the side of the lining component 6, and the steel plates 7 are connected by a hinge 8. The loading end is first welded to the designed loading end pad 10 and the reaction frame vertical beam 2. Then, the back side of the jack 9 is placed tightly against the cross-section of the loading end pad 10. Since the loading end pad 10 and the cross-section of the lining component 6 have the same inclination angle, the end of the jack 9 is perpendicular to the loading end cross-section of the lining component 6. To prevent stress concentration at the loading end, a steel plate 7 and a hinge 8 are placed in the middle between the end of the jack 9 and the loading end cross-section of the lining component 6. The inclination angle of the steel plate 7 is consistent with that of the loading end pad 10, ensuring that the load is applied perpendicularly to the cross-section of the lining component 6 when the load is applied. This completes the assembly of the loading device. During the test, the lining component 6 is loaded using the hydraulic pump of the jack 9.

[0033] Multiple evenly distributed hard rubber pads 5 are provided circumferentially on the back side of the lining component 6. The hard rubber pads 5 are connected to the I-beams 4. An inclined support 3 is provided above the I-beams 4, circumferentially arranged along the curvature of the lining component 6. The inclined support 3 is welded to the reaction frame beam 1. In addition, a certain number of strain gauges and displacement gauges need to be arranged on the lining component 6 to measure strain, displacement and other related data. When placing the hard rubber pads 5 circumferentially on the back side, sufficient space must be reserved for the strain gauges and other related measurement components to avoid affecting the subsequent measurement and reading of results. The loading device constrains the lining component 6 by setting the inclined support 3, I-beams 4, hard rubber pads 5 and other components circumferentially on the back side of the lining component 6, thereby simulating the resistance of the surrounding rock behind the lining during loading. First, weld the inclined support 3 onto the reaction frame beam 1. Then, weld the I-beam 4 onto the other side of the inclined support 3. Arrange the hard rubber pad 5 on the other side of the I-beam 4 to complete the installation of the components that resist the force behind the lining component 6. The size and distribution of the hard rubber pad 5 should leave enough space for the strain gauges on the surface of the lining component 6. The inclination angle of the inclined support 3 is designed according to the position of the hard rubber pad 5 to ensure that the components can fit tightly together.

[0034] A method for using a loading device that simulates the actual stress conditions of a tunnel lining includes the following steps:

[0035] S1. Place two vertical reaction frame beams 2 parallel to each other at a certain distance, and connect them in the middle with two horizontal reaction frame beams 1. Weld them to the joint of the horizontal reaction frame beams 1 at a certain distance inside the end of the vertical reaction frame beam 2 to complete the installation of the reaction frame.

[0036] When assembling the reaction frame, high-rigidity I-beams 4 should be selected to avoid excessive load during component testing, which could lead to local deformation and damage to the reaction frame. The distance between the ends of the horizontally welded I-beams 4 and the vertically placed I-beams 4 should not be too long to allow sufficient space inside the reaction frame for placing the lining component 6, the inclined support 3, and the jacks 9, etc. To ensure a firm connection between the horizontal beam 1 and the vertical beam of the reaction frame, prestressed steel reinforcement bundles and other devices should be used to restrain them at the welding positions of the horizontal I-beams 4. The height of the reaction frame needs to be adjusted according to the thickness of the lining component 6 to be loaded. Before assembling the lining component 6, the difference between the component thickness and the height of the reaction frame should be calculated. Loading end shims 10 and fixing end shims 11 should be placed under the reaction frame and the lining component 6 to raise them as a whole, so that the central axis in the thickness direction of the two is consistent, so that the load of the jacks 9 is aligned with the central axis of the lining component 6 during subsequent loading, without generating eccentric loads in the thickness direction.

[0037] S2. Determine the tilt angles of the loading end shim 10 and the fixed end shim 11 based on the tilt angles of the left and right sides of the lining component 6. After the loading end shim 10 and the fixed end shim 11 are manufactured, weld them to the corresponding positions on the reaction frame.

[0038] The loading end shim 10 and the fixed end shim 11 are located on both sides of the lining member 6. When loading the lining member 6, loading is performed from one side of the lining member 6 while the other side remains stationary. The inclination angle of the shim must be consistent with the inclination angle of the side of the lining member 6 it contacts, ensuring that the side of the fixed end of the lining member 6 can fully contact the fixed end shim 11. This avoids stress concentration caused by local contact between the side of the lining member and the shim due to different inclination angles, which could lead to premature cracking of the lining member 6 at the stress concentration point during loading. Both the loading end shim 10 and the fixed end shim 11 must be made of materials with high rigidity to avoid deformation during loading due to insufficient rigidity, which would affect the test results. The position of the shim needs to be determined in advance before assembly. Generally, a rigid iron plate is selected as the shim and welded to the designated position.

[0039] S3. Place the lining component 6 with one side tightly against the fixed end shim 11, and place the back of the jack 9 tightly against the loading end shim 10. The lateral length of the loading end shim 10 needs to be calculated in advance to ensure that after placing the lining component 6 and the jack 9, the top of the jack 9 is placed between the side of the lining component 6 and the side of the lining component 6.

[0040] The jack 9 needs to be placed with its back side tightly against the loading end shim 10. Since the loading end shim 10 has the same inclination angle as the loading end side of the lining member 6, the jack 9 is placed perpendicular to the side of the lining member 6, which ensures that the load can be applied perpendicularly to the member cross-section during loading. A steel plate 7 is placed between the end of the jack 9 and the lining member 6 to ensure that the load is applied evenly to the cross-section of the lining member 6. The lateral lengths of the loading end shim 10 and the fixed end shim 11 are determined according to the actual situation. Generally, the specific dimensions of the shims, jack 9, hard rubber pad 5, steel plate 7, etc. are first measured on the drawings to ensure that all components can make tight contact during final assembly.

[0041] S4. Several hard rubber pads 5 are evenly arranged on the back side of the lining component 6. I-beams 4 are connected to the rubber pads. Inclined supports 3 are set in the circumferential direction according to the curvature of the lining component 6. The I-beams 4 and the inclined supports 3 are welded together. The inclined supports 3 are welded to the reaction frame beam 1. The load is applied to the lining component 6 by the hydraulic pump truck with jacks 9.

[0042] The hard rubber pads 5 on the back side of the lining component 6 need to be evenly distributed along the circumference of the lining component 6. In addition, since a certain number of strain gauges and displacement gauges need to be arranged on the lining component 6 to measure strain, displacement and other related data, sufficient space must be reserved for the strain gauges and other related measurement data components when placing the hard rubber pads 5 on the back side to avoid affecting the measurement and reading of subsequent results. The hard rubber pads 5 are connected to the I-beam 4, and the I-beam 4 is welded with inclined supports 3. The inclined supports 3 are welded to the reaction frame beam 1, and the whole serves as the resistance of the lining component 6 during the loading process to simulate the surrounding rock resistance of the actual tunnel lining component 6. The inclination angle of the inclined supports 3 is determined based on the hard rubber pads 5 to ensure that the lining component 6 is tightly attached to the back side of the lining component 6.

[0043] After welding the inclined support 3, install the I-beam 4, then arrange the hard rubber pad 5 accordingly, and then place the lining component 6 with the strain gauge attached. Add a steel plate 7 between the jack 9 and the side of the lining component 6 at the loading end to ensure a good fit. Complete all assembly work for the loading test. When applying the load, apply the load to the lining component 6 through the oil pump of the jack 9.

[0044] Therefore, the present invention adopts the above-mentioned loading device and method for simulating the actual stress condition of tunnel lining, which solves the problem that the existing loading methods for simulating tunnel lining components cannot well reflect the actual stress condition of tunnel lining.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A loading device for simulating the actual stress conditions of a tunnel lining, characterized in that: The utility model relates to a loading device, including counterforce frame, lining component, the lining component is arc, the counterforce frame includes counterforce frame crossbeam and counterforce frame vertical column, two counterforce frame crossbeam and counterforce frame vertical column are equipped with two respectively, two counterforce frame vertical column are placed in parallel at a distance apart, are connected through two counterforce frame crossbeam, the lining component is located counterforce frame inside, the lining component one end is fixed end, and its other end is loading end, the fixed end is equipped with fixed end gasket, and the loading end is equipped with loading end gasket, and the loading end gasket is equipped with jack between loading end, The back of the jack is placed close to the loading end gasket, and a steel plate is provided between the top of the jack and the side of the lining component, A plurality of evenly distributed hard rubber pads are provided on the back of the lining component, the hard rubber pads are connected to I-beams, and inclined supports are provided on the I-beams along the curvature of the lining component, The use method of the loading device comprises the following steps: S1, two counterforce frame vertical columns are placed vertically and in parallel at a distance apart, and the two are connected by two counterforce frame crossbeams, the end of the vertical counterforce frame vertical column is offset inward by a certain distance, and the joint with the counterforce frame crossbeam is welded to complete the installation of the counterforce frame; S2, the inclination angles of the loading end gasket and the fixed end gasket are determined according to the inclination angles of the left and right sides of the lining component, and the loading end gasket and the fixed end gasket are welded on the corresponding positions of the counterforce frame after being manufactured; S3, the lining component is placed close to the fixed end gasket on one side, the back of the jack is placed close to the loading end gasket, and the horizontal length of the loading end gasket is calculated in advance to ensure that the steel plate is placed between the top of the jack and the side of the lining component after the lining component and the jack are placed; S4, a plurality of hard rubber pads are arranged evenly on the back of the lining component, the rubber pads are connected to I-beams, inclined supports are arranged along the curvature of the lining component, the I-beams are welded with the inclined supports, the inclined supports are welded on the counterforce frame crossbeams, and the lining component is loaded by a jack oil pump truck.

2. The loading device for simulating actual stress conditions of a tunnel lining according to claim 1, characterized in that: The fixed end gasket is inclined on one side and consistent with the inclination of the fixed end, and the other side is connected to the counterforce frame vertical column close to the fixed end.

3. The loading device for simulating actual stress conditions of a tunnel lining according to claim 1, characterized in that: The loading end gasket is inclined on one side and consistent with the inclination of the loading end, and the other side is connected to the counterforce frame vertical column close to the loading end.

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