Methods for measuring internal forces in existing tunnel lining structures
By setting up a measurement space and installing strain gauges inside the tunnel, and drilling to collect strain data, the problem of measuring the internal forces of existing tunnel lining structures was solved. This enabled the assessment of the stress state of tunnels without pre-embedded instruments and provided a basis for tunnel remediation plans.
Patent Information
- Application Number
- CN202211364138.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-02
- Publication Date
- 2026-03-06
- Estimated Expiration
- 2042-11-02
AI Technical Summary
Existing technologies cannot effectively measure the internal force state of existing tunnel lining structures without pre-embedded instruments, resulting in a lack of basis for tunnel engineering remediation plans and an inability to monitor the development process of defects over a long period of time.
A measurement space is set up inside the tunnel, and first and second measurement points are located. A core hole and a measurement hole are opened at the measurement points, strain gauges are installed, a hollow cylinder is drilled and strain data is read, and stress components are calculated to obtain stress data of the tunnel lining.
It enables accurate assessment of the stress state of existing tunnel lining structures without pre-embedded instruments, providing a basis for formulating remediation plans and ensuring the safety assessment of tunnel structures.
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Figure CN115898535B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of existing tunnel engineering technology, and more specifically, to a method for measuring the internal forces of existing tunnel lining structures. Background Technology
[0002] Currently, composite lining is widely used in tunnel engineering design in China. To obtain the internal force state of the tunnel lining, the common method is to pre-embed measuring instruments (steel strain gauges and concrete strain gauges) in the steel reinforcement cage or internal structure before lining pouring (e.g.,...). Figure 1 and Figure 2 As shown in the diagram, the instrument's lead wire is led out through small holes in the lining. This method is only applicable when the internal forces to be obtained have been determined during tunnel construction. If no instruments are pre-embedded during construction, there is currently no solution for obtaining the actual state of the tunnel lining's internal forces. In recent years, with the increasing number of completed and opened tunnel projects in my country, many existing tunnel projects have experienced varying degrees of defects such as invert heave, lining cracking, lining damage, or water leakage. These defects reduce the overall safety of the tunnel structure. Therefore, it is necessary to conduct safety assessments of existing tunnel structures exhibiting these defects.
[0003] Because no measuring instruments were pre-installed at the locations of defects in these existing tunnels during construction, it is impossible to obtain the true stress state of the tunnel lining structure through measurement. Since the stress state of the tunnel lining is a prerequisite for evaluating existing tunnel structures, this leads to a certain degree of uncertainty in the remediation plans for tunnel projects. Furthermore, for some tunnel projects, defects have a development process, often requiring long-term monitoring of the affected lining structure (e.g., crack width and lining stress) to determine the structural safety status based on the monitoring data. Summary of the Invention
[0004] The present invention includes, for example, providing a method for measuring the internal forces of existing tunnel lining structures, which can detect the internal forces of the tunnel lining of existing tunnels.
[0005] The embodiments of the present invention can be implemented as follows:
[0006] This invention provides a method for measuring the internal forces of existing tunnel lining structures, comprising:
[0007] Set up a measurement space inside the tunnel;
[0008] Locate a first measurement point and a second measurement point within the measurement space. The first measurement point is located on the inner surface of the tunnel lining, and the second measurement point is located on the outer surface of the measurement space near the outer side of the tunnel lining.
[0009] Along a direction perpendicular to the tunnel lining surface, a first set of large core holes and a first set of small core holes are opened at a first measuring point, and a second set of large core holes and a second set of small core holes are opened at a second measuring point; wherein, the axis of the first set of small core holes coincides with the axis of the first set of large core holes, the axis of the second set of small core holes coincides with the axis of the second set of large core holes, and the axis of the first set of small core holes coincides with the axis of the second set of small core holes; the first set of small core holes is located at the bottom of the first set of large core holes, and the second set of small core holes is located at the bottom of the second set of large core holes;
[0010] Three sets of strain gauges are installed in the first and second measuring holes respectively to receive the initial strain data output by all the strain gauges in the first and second measuring holes.
[0011] Along the axial direction of the first measuring hole, drill a first hollow concrete cylinder including the first measuring hole, and drill a second hollow concrete cylinder including the second measuring hole; during the drilling process, continuously read the readings of all strain gauges until the readings no longer change with the drilling depth, remove the first hollow concrete cylinder and the second hollow concrete cylinder, and read the readings of all strain gauges again.
[0012] In an optional implementation, the step of setting up a measurement space within the tunnel includes:
[0013] Auxiliary chambers are set up on the sidewalls of existing tunnels or existing auxiliary chambers are directly utilized, and measurement spaces are opened on the sidewalls of the auxiliary chambers along the axis of the existing tunnel.
[0014] In an alternative implementation, the measurement space is located on the side of the tunnel facing the rock strata.
[0015] In an optional implementation, the axes of the first and second measuring apertures coincide and are perpendicular to the axial direction of the tunnel.
[0016] In an optional implementation, the three strain gauges are projected at 120° angles to each other along the axis of the first or second measuring aperture.
[0017] In an optional implementation, each strain gauge includes four strain gauges;
[0018] The four strain gauges are oriented at 0°, 45°, 90° and 135° to the hole axis, respectively.
[0019] In an optional implementation, the lining stress is calculated by measuring the borehole strain change value caused by stress change using twelve strain gauges. The formula is as follows: due to the different θ angles, three different strain values will be obtained in three different strain gauges, so there will be three different equations (1), (2), (3), and (4). Finally, a total of 12 equations about stress components will be obtained, including 6 independent equations, which can be used to solve the stress component values.
[0020]
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[0026] The beneficial effects of the embodiments of the present invention include:
[0027] The existing method for measuring the internal forces of tunnel lining structures includes: setting up a measurement space inside the tunnel; locating a first measurement point and a second measurement point within the measurement space, the first measurement point being located on the inner surface of the tunnel lining, and the second measurement point being located on the outer surface of the measurement space near the outer side of the tunnel lining; opening a first core borehole and a first measuring hole at the first measurement point along a direction perpendicular to the tunnel lining surface, and opening a second core borehole and a second measuring hole at the second measurement point; wherein the axis of the first measuring hole coincides with the axis of the first core borehole, the axis of the second measuring hole coincides with the axis of the second core borehole, and the axis of the first measuring hole coincides with the axis of the second measuring hole; the first measuring hole is located at... At the bottom of the first set of core holes, the second measuring hole is located at the bottom of the second set of core holes; three sets of strain gauges are installed in the first and second measuring holes respectively to receive the initial strain data output by all strain gauges in the first and second measuring holes; along the axial direction of the first measuring hole, a first hollow concrete cylinder including the first measuring hole and a second hollow concrete cylinder including the second measuring hole are drilled; during the drilling process, the readings of all strain gauges are continuously read until the readings no longer change with the drilling depth, the first and second hollow concrete cylinders are removed, and the readings of all strain gauges are read again.
[0028] The existing method for measuring the internal forces of tunnel lining structures can set up a measurement space inside the tunnel, locate a first measurement point and a second measurement point within the measurement space, and obtain stress data of the tunnel lining by opening a first core large hole, a first measurement small hole, a second core large hole and a second measurement small hole at the first measurement point and the second measurement point respectively. After obtaining a first hollow concrete cylinder with strain gauges and a second hollow concrete cylinder with strain gauges, the circumferential stress value at the core sampling point on the inner and outer surfaces of the tunnel lining is calculated according to the stress-strain correspondence.
[0029] This allows us to use the aforementioned method for measuring the internal forces of existing tunnel lining structures to measure the stress state of existing tunnels without pre-embedded instruments, thereby enabling an accurate assessment of the stress state of the tunnel structure and providing a basis for developing a remediation plan for the tunnel structure. Attached Figure Description
[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0031] Figure 1 This is a schematic diagram of the installation of a steel bar strain gauge in the prior art;
[0032] Figure 2 This is a schematic diagram of the installation of concrete strain gauges in the prior art;
[0033] Figure 3 This is a step diagram of the existing method for measuring the internal forces of tunnel lining structures in an embodiment of the present invention;
[0034] Figure 4 This is a schematic diagram illustrating the setting of the measurement space within the tunnel from a first-view perspective in an embodiment of the present invention;
[0035] Figure 5 This is a schematic diagram illustrating the setting of the measurement space from a second perspective within the tunnel in an embodiment of the present invention;
[0036] Figure 6 This is a schematic diagram showing the arrangement of the first and second measurement points within the measurement space in an embodiment of the present invention;
[0037] Figure 7 This is a schematic diagram of the setting of the measuring hole in an embodiment of the present invention, wherein B is a schematic diagram of the large hole of the core, C is a schematic diagram of the large hole of the core and the small measuring hole, D is a schematic diagram of the large hole of the core, the small measuring hole and the strain gauge, and E is a schematic diagram of the large hole of the core, the small measuring hole, the strain gauge and the hollow concrete cylinder.
[0038] Figure 8 This is a schematic diagram showing the setting of the first viewpoint of the strain gauge in an embodiment of the present invention;
[0039] Figure 9 This is a schematic diagram showing the setting of the second perspective of the strain gauge in an embodiment of the present invention;
[0040] Figure 10 This is a schematic diagram of the strain gauge arrangement in an embodiment of the present invention.
[0041] Icons: 100-Tunnel; 110-Measurement space; 111-First measurement point; 112-Second measurement point; 113-First core borehole; 114-Second core borehole; 115-First measurement small borehole; 121-Strain gauge; 122-Strain gauge; 130-First hollow concrete cylinder; 101-Auxiliary chamber. Detailed Implementation
[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0045] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0046] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.
[0047] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.
[0048] Please refer to Figures 3-7 This embodiment provides a method for measuring the internal forces of the lining structure of an existing tunnel 100, including:
[0049] S1: Set up a measurement space 110 inside tunnel 100;
[0050] S2: Locate the first measurement point 111 and the second measurement point 112 within the measurement space 110. The first measurement point 111 is located on the inner surface of the tunnel lining 100, and the second measurement point 112 is located on the outer surface of the measurement space 110 near the outer side of the tunnel lining 100.
[0051] S3: Along a direction perpendicular to the lining surface of tunnel 100, a first core large hole 113 and a first measuring small hole 115 are opened at the first measuring point 111, and a second core large hole 114 and a second measuring small hole are opened at the second measuring point 112; wherein, the axis of the first measuring small hole 115 coincides with the axis of the first core large hole 113, the axis of the second measuring small hole coincides with the axis of the second core large hole 114, and the axis of the first measuring small hole 115 coincides with the axis of the second measuring small hole; the first measuring small hole 115 is located at the bottom of the first core large hole 113, and the second measuring small hole is located at the bottom of the second core large hole 114;
[0052] S4: Three sets of strain gauges 121 are installed in the first measuring hole 115 and the second measuring hole respectively, and the initial strain data output by all strain gauges 121 in the first measuring hole 115 and the second measuring hole are received.
[0053] S5: Drill the first hollow concrete cylinder 130, including the first measuring hole 115, and drill the second hollow concrete cylinder, including the second measuring hole, along the axial direction of the first measuring hole 115; and continuously read the readings of all strain gauges 121 during the drilling process until the readings no longer change with the drilling depth, remove the first hollow concrete cylinder 130 and the first hollow concrete cylinder 130, and read the readings of all strain gauges 121 again.
[0054] Please refer to Figures 3-7 The principle of the existing method for measuring the internal forces of the lining structure of tunnel 100 is as follows:
[0055] The existing method for measuring the internal forces of the tunnel lining structure can set up a measurement space 110 inside the tunnel 100, and locate a first measurement point 111 and a second measurement point 112 within the measurement space 110. Based on the method of opening a first core large hole 113, a first measurement small hole 115, a second core large hole 114, and a second measurement small hole at the first measurement point 111 and the second measurement point 112 respectively, the stress data of the tunnel lining 100 can be obtained. After obtaining a first hollow concrete cylinder with a strain gauge 121 and a second hollow concrete cylinder with a strain gauge 121, the circumferential stress value at the core sampling point on the inner and outer surfaces of the tunnel lining 100 can be calculated according to the stress-strain correspondence.
[0056] Therefore, the aforementioned method for measuring the internal forces of the lining structure of the existing tunnel 100 can be used to measure the stress state of the existing tunnel 100 without pre-embedded instruments, thereby enabling an accurate assessment of the stress state of the tunnel 100 structure and providing a basis for formulating a remediation plan for the tunnel 100 structure.
[0057] Further, please refer to Figures 3-7 In this embodiment, the step of setting up a measurement space 110 within the tunnel 100 includes:
[0058] An auxiliary chamber 101 is set up on the side wall of the existing tunnel 100 or an existing auxiliary chamber 101 is directly used, and a measurement space 110 is opened on the side wall of the auxiliary chamber 101 along the axis of the existing tunnel 100.
[0059] As can be seen from the above, in this embodiment, when locating the first measuring point 111 and the second measuring point 112, the first measuring point 111 is located on the inner side of the measuring space 110 near the tunnel 100, while the second measuring point 112 is located on the outer side of the measuring space 110 near the tunnel 100. Therefore, in order to facilitate the determination of the first measuring point 111 and the second measuring point 112, the measuring space 110 can be located on the outer side of the tunnel 100 facing the lining, thereby ensuring that the lining concrete strain at the first measuring point 111 and the second measuring point 112 is in its initial state.
[0060] In addition, the measuring space 110 is located on the side of the tunnel 100 facing the rock strata; and the axes of the first measuring hole 115 and the second measuring hole coincide and are perpendicular to the axis of the tunnel 100.
[0061] Based on the above, please refer to Figures 3-10 In this embodiment, the projections of the three strain gauges 121 along the axis of the first measuring aperture 115 or the second measuring aperture form a 120° angle between each other. Moreover, each strain gauge 121 includes four strain elements 122; the directions of the four strain elements 122 are 0°, 45°, 90° and 135° with the aperture axis, respectively.
[0062] Therefore, based on the above content, the lining stress is calculated by measuring the borehole strain change value caused by stress change using twelve strain gauges 122. The formula is as follows. Due to the different angles θ, three different strain values will be obtained in three different strain gauges, so there will be three different equations (1), (2), (3), and (4). Finally, a total of 12 equations about stress components will be obtained, including 6 independent equations, which can solve the value of stress components.
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[0069] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for measuring internal forces of an existing tunnel lining structure, characterized by, The application relates to a method for measuring the stress of a tunnel lining. The method comprises the following steps: a measuring space is arranged in the tunnel, an auxiliary chamber is arranged on the side wall of the existing tunnel or an existing auxiliary chamber is directly used, and the measuring space is arranged on the side wall of the auxiliary chamber along the axis direction of the existing tunnel; a first measuring point and a second measuring point are positioned, the first measuring point is located on the inner surface of the tunnel lining, and the second measuring point is located on the outer surface of the measuring space close to the outer side of the tunnel lining; a first sleeve large hole and a first measuring small hole are arranged at the first measuring point along the direction perpendicular to the surface of the tunnel lining, and a second sleeve large hole and a second measuring small hole are arranged at the second measuring point; the axis of the first measuring small hole coincides with the axis of the first sleeve large hole, the axis of the second measuring small hole coincides with the axis of the second sleeve large hole, and the axis of the first measuring small hole coincides with the axis of the second measuring small hole; the first measuring small hole is located at the bottom of the first sleeve large hole, and the second measuring small hole is located at the bottom of the second sleeve large hole; the axes of the first measuring small hole and the second measuring small hole coincide and are perpendicular to the axis direction of the tunnel; three groups of strain gauges are arranged in the first measuring small hole and the second measuring small hole respectively, initial strain data output by all the strain gauges in the first measuring small hole and all the strain gauges in the second measuring small hole are received; a first hollow concrete cylinder including the first measuring small hole is drilled along the axis direction of the first measuring small hole, and a second hollow concrete cylinder including the second measuring small hole is drilled; during the drilling process, the readings of all the strain gauges are continuously read until the readings no longer change with the drilling depth, the first hollow concrete cylinder and the second hollow concrete cylinder are taken out, and the readings of all the strain gauges are read again; the measuring space is located on the side of the tunnel facing the rock stratum; the projections of the three strain gauges along the axis of the first measuring small hole or the second measuring small hole form an angle of 120 degrees with each other; each strain gauge comprises four strain gauges; the directions of the four strain gauges are 0 degrees, 45 degrees, 90 degrees and 135 degrees with respect to the hole axis respectively.