A device for testing dynamic response of a cracked tunnel lining

Abstract

The utility model discloses a kind of crack tunnel lining dynamic response testing devices, it includes subway tunnel scale model, subway operation load simulation system, data acquisition analysis system, acceleration sensor group, stratum restraint simulation system, strain gauge group, tunnel scale model includes lining model part, ballast model part, lining model part preset prefabricated crack;Stratum restraint simulation system includes digital pressure controller, test reaction frame, test reaction frame is equipped with several servo loading cylinders, the loading end of each servo loading cylinder is respectively equipped with arc transmission force cushion block, and pressure sensor is respectively equipped between each arc transmission force cushion block and the loading end of corresponding servo loading cylinder;Strain gauge group includes several strain gauges, the several strain gauges of strain gauge group are laid in vault position, haunch position, arch foot position, inverted arch position, the tip area of prefabricated crack of lining model part. The utility model has the advantages of novel design, high test operation efficiency and good test reliability.

Description

Technical Field

[0001] This utility model relates to the field of tunnel and underground engineering testing technology, and in particular to a dynamic response testing device for tunnel lining with cracks. Background Technology

[0002] During long-term operation, subway tunnel lining structures are continuously subjected to cyclic dynamic loads from trains, as well as the coupled effects of ground pressure, groundwater erosion, and disturbances from surrounding construction. Under these complex conditions, the concrete material of the tunnel lining gradually fatigues and ages, and cracks easily develop and spread in its weak points, such as joints and near construction joints. This type of structural damage not only undermines the integrity of the tunnel lining, but more importantly, it significantly alters the local stiffness and dynamic transmission path of the structure. Under the subsequent continuous train vibration load, a significant stress concentration effect will occur at the crack tip, leading to abnormal accumulation and release of vibration energy in the damaged area. This amplifies the dynamic response of the tunnel lining, such as acceleration and dynamic strain, and accelerates the accumulation and spread of damage, posing a serious threat to the long-term operational safety of the tunnel structure.

[0003] Among them, the Chinese invention patent with patent number ZL202210407616.5 and patent name: Test Device and Test Method for Full Life Cycle Health Monitoring of Subway Tunnel Structures, substantially discloses a tunnel lining dynamic response testing device; specifically, the test device for full life cycle health monitoring of subway tunnel structures discloses the following technical solution: a test device for full life cycle health monitoring of subway tunnel structures, including a test soil sample filled with simulated soil in a model box, a tunnel model simulating a tunnel embedded in the test soil sample, the tunnel model being composed of a reinforced concrete integrally cast annular lining structure and a track bed structure at the bottom of the inner cavity of the annular lining structure; a vibration device is installed on the track bed structure; a pressure sensor is installed between the vibration device and the track bed structure; acceleration sensors are installed directly above the central axis of the tunnel model and on the inner walls of both sides, the tunnel model can be a damaged tunnel model simulating a tunnel damage state with cracks in the annular lining structure, the vibration device, pressure sensor and acceleration sensor are all electrically connected to a dynamic signal testing, analysis and control system.

[0004] The testing process of the aforementioned experimental device for full life-cycle health monitoring of subway tunnel structures includes the following steps: A. Fill the model box with test soil samples simulating soil, and bury the healthy tunnel model; B. The dynamic signal test analysis and control system starts the excitation equipment to generate excitation vibrations at a set frequency, amplitude, and duration to simulate the vibration load on the tunnel when a train of a set type and speed passes through the tunnel, and uses pressure sensors for feedback control; at the same time, during the excitation vibration process, the dynamic signal test analysis and control system collects and records the excitation vibration signals of the tunnel model measured by all acceleration sensors; then, the excitation vibration is stopped. C. The dynamic signal test analysis and control system processes the excited vibration signal to obtain the time-domain waveform and frequency-domain curve of the excited vibration of the tunnel model, thereby completing the tunnel model test.

[0005] It should be noted that the aforementioned experimental device for full life-cycle health monitoring of subway tunnel structures still has the following shortcomings, specifically: Defect 1: The static confining pressure of the test model comes from the test soil sample filled in the model box. This requires the test soil sample to be cast before the test, and the cast test soil sample also needs to be cured, which obviously affects the efficiency of the test operation. In addition, the cast test soil sample is difficult to accurately simulate the confining pressure of the actual strata on the tunnel structure. Defect 2: During the testing of the tunnel model, the test device for the full life cycle health monitoring of the subway tunnel structure does not monitor the strain of the tunnel model, that is, it cannot obtain the strain distribution of the tunnel model and accurately capture the dynamic strain concentration effect in the crack area. Therefore, the test device for the full life cycle health monitoring of the subway tunnel structure has the defect of poor test reliability. Utility Model Content

[0006] The purpose of this invention is to provide a dynamic response testing device for cracked tunnel lining, which addresses the shortcomings of existing technologies. This device features a novel structural design, high testing efficiency, and good testing reliability.

[0007] To achieve the above objectives, this utility model is implemented through the following technical solution.

[0008] A dynamic response testing device for cracked tunnel lining includes a scaled-down model of a subway tunnel, a subway operation load simulation system, a data acquisition and analysis system, and an acceleration sensor group composed of several acceleration sensors. The scaled-down model of the tunnel includes a lining model section and a track bed model section. The lining model section is pre-fabricated with pre-cast cracks for simulating structural crack damage that exists in the subway tunnel lining during operation. The subway operation load simulation system is used to apply dynamic loads to the track bed model of the subway tunnel scale model. Several acceleration sensors in the acceleration sensor group are arranged on the inner surface of the lining model of the subway tunnel scale model, and each acceleration sensor is electrically connected to the data acquisition and analysis system. The dynamic response testing device for the lining of a cracked tunnel also includes a ground constraint simulation system. The ground constraint simulation system includes a digital pressure controller and a test reaction frame fixed to the foundation by anchor bolts. The test reaction frame is equipped with several servo loading cylinders arranged at intervals around the periphery of the scale model of the subway tunnel. Each servo loading cylinder has an arc-shaped force transmission pad that is in contact with the outer surface of the lining model. Each arc-shaped force transmission pad and the corresponding servo loading cylinder are equipped with a pressure sensor. Each pressure sensor and each servo loading cylinder are electrically connected to the digital pressure controller. The dynamic response testing device for the lining of a cracked tunnel also includes a strain gauge group, which consists of several strain gauges. These strain gauges are placed at the arch crown, arch waist, arch foot, invert arch, and the tip area of ​​the precast crack in the lining model. Each strain gauge is electrically connected to the data acquisition and analysis system.

[0009] The lining model section is provided with a dense monitoring area centered on the precast crack, and some strain gauges in the strain gauge group are densely arranged in the dense monitoring area.

[0010] The subway operation load simulation system includes a vibrator, a signal generator, a power amplifier, and a rigid support frame anchored to the foundation by high-strength bolts. The signal output terminal of the signal generator is electrically connected to the signal input terminal of the power amplifier, and the signal output terminal of the power amplifier is electrically connected to the signal input terminal of the vibrator.

[0011] The acceleration sensors in the acceleration sensor group are located at the arch top, arch waist, arch foot, and invert arch positions of the lining model.

[0012] The lining model is provided with a comparison measuring point at the axial position corresponding to the precast crack, and an acceleration sensor is provided on the inner surface of the lining model at the comparison measuring point position.

[0013] The data acquisition and analysis system is equipped with a data acquisition instrument, and each of the acceleration sensors and strain gauges is electrically connected to the signal input terminal of the data acquisition instrument.

[0014] The test reaction frame is a welded steel structure system.

[0015] Compared with the prior art, the present invention has the following beneficial effects, specifically: 1. By combining a digital pressure controller with a pressure sensor, the stratum constraint simulation system can control and monitor the output load of the servo loading cylinder in real time. The servo loading cylinder transmits the load evenly to the outer surface of the lining model through an arc-shaped force transmission pad to accurately simulate the confining pressure of the actual stratum on the tunnel structure. Compared with the existing technology of applying static confining pressure by pouring test soil samples, this utility model can effectively test the work efficiency and accurately simulate the confining pressure of the actual stratum on the tunnel structure. 2. The strain gauge group can form a global strain monitoring network for the scaled-down model of the subway tunnel. This global strain monitoring network can simultaneously acquire the overall strain distribution of the structure and accurately capture the dynamic strain concentration effect in the crack area, thereby effectively improving the testing reliability of the testing device. 3. Therefore, the dynamic response testing device for cracked tunnel lining of this utility model has the advantages of novel structural design, high testing efficiency and good testing reliability. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention.

[0017] Figure 1 This is a schematic diagram of the structure of this utility model.

[0018] Figure 2 This is a partial structural schematic diagram of the present invention.

[0019] Figure 3 This is a structural schematic diagram of the subway operation load simulation system of this utility model.

[0020] exist Figures 1 to 3 This includes: 1-Scaled-down model of subway tunnel; 11-Liner model; 12-Track bed model; 13-Precast crack; 2-Acceleration sensor; 31-Test reaction frame; 32-Servo loading cylinder; 33-Arc-shaped force transmission pad; 34-Pressure sensor; 4-Strain gauge; 51-Vibrator; 52-Rigid support frame. Detailed Implementation

[0021] The present invention will now be described in conjunction with specific embodiments.

[0022] Example 1, as Figure 1 and Figure 2As shown, a dynamic response testing device for a cracked tunnel lining includes a scaled-down model of a subway tunnel 1, a subway operation load simulation system, a data acquisition and analysis system, and an acceleration sensor group composed of several acceleration sensors 2. The scaled-down model of the tunnel includes a lining model section 11 and a track bed model section 12. The lining model section 11 is pre-fabricated with pre-cast cracks 13 for simulating structural crack damage in the subway tunnel lining during operation.

[0023] It should be explained that the accelerometer 2 in the accelerometer sensor group is located at the arch top, arch waist, arch foot, and invert arch positions of the lining model section 11.

[0024] Furthermore, such as Figure 1 As shown, the subway operation load simulation system is used to apply dynamic loads to the track bed model section 12 of the subway tunnel scale model 1. Several acceleration sensors 2 in the acceleration sensor group are arranged on the inner surface of the lining model section 11 of the subway tunnel scale model 1, and each acceleration sensor 2 is electrically connected to the data acquisition and analysis system.

[0025] Furthermore, such as Figure 1 and Figure 2 As shown, the dynamic response testing device for the lining of a cracked tunnel also includes a ground constraint simulation system. This system includes a digital pressure controller and a test reaction frame 31 fixed to the foundation by anchor bolts. The test reaction frame 31 is equipped with several servo loading cylinders 32 spaced apart around the periphery of the scaled-down model 1 of the subway tunnel. Each servo loading cylinder 32 has an arc-shaped force transmission pad 33 at its loading end, which contacts the outer surface of the lining model 11. Pressure sensors 34 are installed between each arc-shaped force transmission pad 33 and the loading end of the corresponding servo loading cylinder 32. Each pressure sensor 34 and each servo loading cylinder 32 are electrically connected to the digital pressure controller. It should be noted that the test reaction frame 31 is a welded steel structure system, and it provides the necessary reaction force support and boundary constraints for the entire ground constraint simulation system.

[0026] In addition, such as Figure 1 and Figure 2 As shown, the dynamic response testing device for the lining of a tunnel with cracks also includes a strain gauge group, which includes several strain gauges 4. The strain gauges 4 are arranged at the arch top, arch waist, arch foot, invert arch and the tip area of ​​the precast crack 13 of the lining model 11. Each strain gauge 4 is electrically connected to the data acquisition and analysis system.

[0027] For the stratum constraint simulation system in this embodiment, during the process of providing static confining pressure to the scaled-down model 1 of the subway tunnel, the pressure of each servo loading cylinder 32 on the outer surface of the lining model is set by the digital pressure controller. Specifically, after the digital pressure controller sets the required pressure value, the digital pressure controller controls the servo loading cylinder 32 to perform loading action. During this process, the pressure sensor 34 obtains the pressure loaded by the corresponding servo loading cylinder in real time and feeds back the pressure value to the digital pressure controller in real time. When the pressure value obtained by the pressure sensor 34 reaches the set value, the servo loader stops its action and maintains a constant pressure on the lining model.

[0028] For the arc-shaped force transmission pad 33 in this embodiment, it enables the pressure applied by the servo loading cylinder 32 to be uniformly applied to the outer surface of the lining model.

[0029] It should be emphasized that this embodiment uses a ground constraint simulation system to apply static confining pressure to the outer circumference of the lining model. A digital pressure controller, in conjunction with a pressure sensor 34, enables control and real-time monitoring of the load output by the servo loading cylinder 32. The servo loading cylinder 32 transmits the load evenly to the outer surface of the lining model via an arc-shaped force transmission pad 33, accurately simulating the confining pressure effect of actual ground on the tunnel structure. Compared to the existing technology that applies static confining pressure by pouring test soil samples, the ground constraint simulation system in this embodiment effectively improves testing efficiency and accurately simulates the confining pressure effect of actual ground on the tunnel structure.

[0030] It should be further emphasized that, for the strain gauge group in this embodiment, it can form a global strain monitoring network for the scaled-down model 1 of the subway tunnel. This global strain monitoring network can simultaneously acquire the overall strain distribution of the structure and accurately capture the dynamic strain concentration effect in the crack area, thereby effectively improving the testing reliability of the testing device.

[0031] It should be noted that the dynamic response testing device for the cracked tunnel lining in this embodiment can be designed specifically for comparative tests. Under the same boundary conditions and load spectrum, it can simultaneously or alternately test the scaled model 1 of the subway tunnel with prefabricated cracks and the scaled model 1 of the intact subway tunnel, thereby providing a unique variable and a highly controllable test environment for accurately quantifying the amplification effect of cracks on dynamic response.

[0032] In summary, the dynamic response testing device for cracked tunnel lining in this embodiment has the advantages of novel structural design, high testing efficiency, and good testing reliability through the above structural design.

[0033] Example 2, as Figure 1 and Figure 2As shown, the difference between this embodiment 2 and embodiment 1 is that: the lining model part 11 is provided with a dense monitoring area centered on the precast crack 13, and some strain gauges 4 in the strain gauge group are densely arranged in the dense monitoring area.

[0034] By densely deploying strain gauges 4 in the tip region of the precast crack 13, the strain gauge group, together with the strain gauges 4 at the arch crown, arch waist, arch foot, and invert arch positions mentioned above, can form a complete strain monitoring system from global to local, thereby further improving the accuracy of strain monitoring.

[0035] Example 3, as Figure 1 and Figure 3 As shown, the difference between this embodiment three and embodiment one is that the subway operation load simulation system includes a vibrator 51, a signal generator, a power amplifier, and a rigid support frame 52 anchored to the foundation by high-strength bolts. The signal output terminal of the signal generator is electrically connected to the signal input terminal of the power amplifier, and the signal output terminal of the power amplifier is electrically connected to the signal input terminal of the vibrator 51.

[0036] When the subway operation load simulation system in this embodiment 3 is working, the signal generator outputs a load carrier-shaped signal that conforms to the operating characteristics of the subway train, which drives the exciter 51 through the power amplifier to realize the dynamic loading of the subway tunnel scale model 1.

[0037] In addition, through the closed-loop control system of "signal generator - power amplifier - exciter 51", this embodiment 3 can programmatically reproduce the complex vibration waveforms of real subway operation.

[0038] Example 4 differs from Example 1 in that: a comparison measuring point is set at the axial position corresponding to the precast crack 13 in the lining model part 11, and an acceleration sensor 2 is arranged on the inner surface of the lining model part 11 at the comparison measuring point position.

[0039] Accelerometers 2 are arranged circumferentially at 45° intervals on the inner surface of the lining model section 11 to ensure the monitoring of vibration acceleration at the arch crown, arch waist, arch foot, and invert arch positions, so as to comprehensively monitor the overall vibration mode of the subway tunnel scale model 1. At the same time, a comparison measuring point is specially added at the axial position corresponding to the precast crack 13 to synchronously measure the vibration acceleration response of the structure, and to focus on analyzing the transmission and change law of vibration energy in the presence of the precast crack 13.

[0040] Example 5 differs from Example 1 in that the data acquisition and analysis system is equipped with a data acquisition instrument, and each acceleration sensor 2 and each strain gauge 4 are electrically connected to the signal input terminal of the data acquisition instrument.

[0041] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A dynamic response testing device for a tunnel lining with cracks, comprising a scaled-down model of a subway tunnel (1), a subway operation load simulation system, a data acquisition and analysis system, and an acceleration sensor group composed of several acceleration sensors (2). The scaled-down model of the tunnel includes a lining model part (11) and a track bed model part (12). The lining model part (11) is pre-set with prefabricated cracks (13) for simulating structural crack damage in the subway tunnel lining during operation. The subway operation load simulation system is used to apply dynamic loads to the track bed model (12) of the subway tunnel scale model (1). Several acceleration sensors (2) in the acceleration sensor group are arranged on the inner surface of the lining model (11) of the subway tunnel scale model (1). Each acceleration sensor (2) is electrically connected to the data acquisition and analysis system. Its features are: The dynamic response testing device for the lining of the tunnel with cracks also includes a ground constraint simulation system. The ground constraint simulation system includes a digital pressure controller and a test reaction frame (31) fixed to the foundation by anchor bolts. The test reaction frame (31) is equipped with several servo loading cylinders (32) arranged at intervals around the periphery of the scale model (1) of the subway tunnel. Each servo loading cylinder (32) has an arc-shaped force transmission pad (33) that is in contact with the outer surface of the lining model (11) at its loading end. Each arc-shaped force transmission pad (33) is equipped with a pressure sensor (34) between its loading end and the corresponding servo loading cylinder (32). Each pressure sensor (34) and each servo loading cylinder (32) are electrically connected to the digital pressure controller. The dynamic response testing device for the lining of the cracked tunnel also includes a strain gauge group, which includes several strain gauges (4). The strain gauges (4) are arranged at the arch top, arch waist, arch foot, invert arch and the tip area of ​​the precast crack (13) of the lining model (11). Each strain gauge (4) is electrically connected to the data acquisition and analysis system.

2. The dynamic response testing device for cracked tunnel lining according to claim 1, characterized in that: The lining model section (11) is provided with a dense monitoring area centered on the precast crack (13), and some strain gauges (4) in the strain gauge group are densely arranged in the dense monitoring area.

3. The dynamic response testing device for cracked tunnel lining according to claim 1, characterized in that: The subway operation load simulation system includes a vibrator (51), a signal generator, a power amplifier, and a rigid support frame (52) anchored to the foundation by high-strength bolts. The signal output terminal of the signal generator is electrically connected to the signal input terminal of the power amplifier, and the signal output terminal of the power amplifier is electrically connected to the signal input terminal of the vibrator (51).

4. The dynamic response testing device for cracked tunnel lining according to claim 1, characterized in that: The acceleration sensor (2) in the acceleration sensor group is located at the arch top, arch waist, arch foot and invert arch positions of the lining model part (11).

5. The dynamic response testing device for cracked tunnel lining according to claim 4, characterized in that: The lining model part (11) is provided with a comparison measuring point at the axial position corresponding to the precast crack (13), and an acceleration sensor (2) is provided on the inner surface of the lining model part (11) at the comparison measuring point position.

6. The dynamic response testing device for cracked tunnel lining according to claim 1, characterized in that: The data acquisition and analysis system is equipped with a data acquisition instrument, and each of the acceleration sensors (2) and strain gauges (4) is electrically connected to the signal input terminal of the data acquisition instrument.

7. The dynamic response testing device for cracked tunnel lining according to claim 1, characterized in that: The test reaction frame (31) is a welded steel structure system.

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