Model test device for tunnel segment monitoring

Abstract

The utility model discloses a model test device for tunnel segment monitoring. The model test device comprises a loading system, a monitoring system and a model, the model comprises a model box, a tunnel reduced scale model and a medium, the tunnel reduced scale model comprises a plurality of segment ring reduced scale models, and grooves used for simulating joints between segments are formed in the peripheries of the segment ring reduced scale models; the tunnel reduced scale model is horizontally placed in the model box, the periphery of the tunnel reduced scale model is surrounded by a medium, the medium can transmit a load, the loading system can apply the load to the medium, and the load applying direction is vertically downward; a fiber bragg grating strain gauge of the monitoring system is arranged on the inner wall of a tunnel reduced scale model, a fiber bragg grating inclinometer is arranged on the side face of the tunnel reduced scale model, fiber bragg grating soil pressure gauges are arranged on the top and the bottom of the tunnel reduced scale model, and a fiber bragg grating displacement meter is arranged on the side face of the tunnel reduced scale model. And the groove is located on the area, close to the groove, of the segment reduced-scale model. On the premise that the cost is controlled, the problems caused by the upper load in the construction period are predicted.

Description

Technical Field

[0001] The utility model relates to the field of tunnel engineering model tests, in particular to a model test device for monitoring tunnel segments. Background Art

[0002] Currently, shield tunnels are widely used in rail transit and municipal pipeline construction. However, during the construction and operation phases of shield tunnels, multiple factors, including overhead loads, stress concentration, and the external environment, can lead to a series of problems, including cracks and fissures in the segments, increased gapping between segment joints, and structural water leakage.

[0003] Of particular concern is the potential damage to the segments caused by overhead loads during construction, which poses a significant risk. This could lead to cracking in the segments later in construction or during operation, potentially causing safety accidents. Therefore, this issue requires significant attention and preventative measures must be prepared. While direct testing on prototype tunnels can reveal potential problems, it is difficult to implement due to the high site requirements and testing costs. Accurately predicting potential problems while controlling costs has become a critical issue that needs to be addressed. Summary of the Invention

[0004] The utility model provides a model test device for monitoring tunnel segments, which is used to predict problems caused by upper loads during construction under the premise of controlling costs.

[0005] In order to achieve the above purpose, the technical solution of the utility model is:

[0006] A model test device for monitoring tunnel segments, comprising: a loading system, a monitoring system and a model;

[0007] The model includes a model box, a tunnel scale model and a medium. The tunnel scale model includes a plurality of segment ring scale models connected in sequence. The outer periphery of the segment ring scale model is provided with a groove for simulating the joints between the segments.

[0008] The scale-down tunnel model is placed horizontally in the model box. The outer periphery of the scale-down tunnel model is surrounded by a medium. The medium can transmit load. The loading system can apply load to the medium. The direction in which the loading system applies load is vertically downward.

[0009] The monitoring system includes a fiber Bragg grating sensor, which includes a fiber Bragg grating strain gauge, a fiber Bragg grating inclinometer, a fiber Bragg grating soil pressure gauge and a fiber Bragg grating displacement meter;

[0010] The fiber Bragg grating strain gauge is arranged on the inner wall of the tunnel scale model, the fiber Bragg grating inclinometer is arranged on the side of the tunnel scale model, the fiber Bragg grating soil pressure gauge is arranged on the top and bottom of the tunnel scale model, and the fiber Bragg grating displacement meter is arranged on the side of the tunnel scale model, and the fiber Bragg grating displacement meter is located on the area of the segment ring scale model close to the groove.

[0011] Furthermore, the loading system includes a control device, a loading device and a pressing plate;

[0012] The pressure plate is fixed on the loading device, and the loading device applies a load to the medium through the pressure plate. The control device can control the magnitude of the load applied by the loading device.

[0013] Furthermore, the monitoring system also includes a fiber Bragg grating demodulator and a monitoring device;

[0014] The fiber Bragg grating demodulator is connected to the fiber Bragg grating sensor, and the fiber Bragg grating demodulator is connected to the monitoring device.

[0015] Furthermore, the control device can control the loading device to load in stages.

[0016] Furthermore, adjacent segment ring scale models are assembled with staggered seams.

[0017] Beneficial effects:

[0018] The utility model provides a model test device for monitoring tunnel segments. A vertical downward load is applied to a medium through a loading system, and the load is transmitted to a tunnel scale model through the medium to simulate the influence of the upper load on the tunnel segments during actual construction. The fiber optic Bragg grating sensor of the monitoring system is used to monitor the tunnel scale model in real time, and the critical load at which the tunnel scale model is destroyed under the action of the upper load is obtained. Based on this data, the critical load at which the prototype tunnel is destroyed can be calculated. The results of the model test are used to predict possible problems so that necessary reinforcement measures and structural optimization can be taken before the formal construction process to ensure the safety and stability of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the 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 labor.

[0020] Figure 1 This is a structural schematic diagram of a model test device for tunnel segment monitoring disclosed in the utility model;

[0021] Figure 2 A schematic diagram of a tunnel scale model of a model test device for tunnel segment monitoring disclosed in the present utility model;

[0022] Figure 3 This is a schematic diagram of the installation of a monitoring system for a model test device for monitoring tunnel segments disclosed in the present utility model;

[0023] Figure 4 A schematic side view of a scaled model of a segment ring of a model test device for tunnel segment monitoring disclosed in the present utility model;

[0024] Figure 5 This is a front view of a scaled model of a segment ring of a model test device for tunnel segment monitoring disclosed in the utility model.

[0025] In the picture:

[0026] 1. Model box;

[0027] 2. Medium;

[0028] 31. Control device; 32. Loading device; 33. Press plate; 34. Frame;

[0029] 41. Fiber Bragg grating strain gauge; 42. Fiber Bragg grating inclinometer; 43. Fiber Bragg grating soil pressure gauge; 44. Fiber Bragg grating displacement meter; 45. Fiber Bragg grating demodulator; 46. Monitoring device;

[0030] 5. Scaled model of the tunnel; 51. Longitudinal connecting bolts; 52. Grooves; 5A. Scaled model of the first segment ring; 5B. Scaled model of the second segment ring; 5C. Scaled model of the third segment ring; 5D. Scaled model of the fourth segment ring; 5E. Scaled model of the fifth segment ring; 5F. Scaled model of the sixth segment ring; 5G. Scaled model of the seventh segment ring;

[0031] B, standard block area; F, capped block area; L, adjacent block area. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] This embodiment provides a model test device for monitoring tunnel segments, comprising: a loading system, a monitoring system, and a model;

[0034] like Figure 1 As shown, the model includes a model box 1, a tunnel scale model 5 and a medium 2. The tunnel scale model 5 includes a plurality of segment ring scale models connected in sequence. The outer periphery of the segment ring scale model is provided with grooves 52 for simulating joints between segments, so as to simulate the structure of the prototype tunnel to the greatest extent.

[0035] The scaled tunnel model 5 is placed horizontally in the model box 1. The outer periphery of the scaled tunnel model 5 is surrounded by a medium 2. The medium 2 is capable of transmitting load. In this embodiment, the medium 2 is soil. The loading system is capable of applying a load to the medium 2. The direction in which the loading system applies the load is vertically downward.

[0036] The monitoring system includes a fiber grating sensor, such as Figure 3 As shown, the fiber Bragg grating sensor includes a fiber Bragg grating strain gauge 41, a fiber Bragg grating inclinometer 42, a fiber Bragg grating soil pressure gauge 43 and a fiber Bragg grating displacement meter 44;

[0037] The fiber Bragg grating strain gauge 41 is arranged on the inner wall of the tunnel scale model 5 to measure the strain of the tunnel scale model 5. The fiber Bragg grating inclinometer 42 is arranged on the side of the tunnel scale model 5 to measure the inclination of the tunnel scale model 5. The fiber Bragg grating soil pressure gauge 43 is arranged at the top and bottom of the tunnel scale model 5 to measure the pressure exerted on the tunnel scale model 5. The fiber Bragg grating displacement meter 44 is arranged on the side of the tunnel scale model 5, and the fiber Bragg grating displacement meter 44 is located in the area of the pipe ring scale model near the groove 52 to measure the change in the opening amount of the groove 52 of the tunnel scale model 5. By arranging the fiber Bragg grating sensors at specific positions on the tunnel scale model 5, the accuracy of the monitoring data is ensured.

[0038] In this embodiment, the fiber Bragg grating strain gauge 41 is attached to the inner wall of the tunnel scale model 5, and the fiber Bragg grating inclinometer 42, the fiber Bragg grating earth pressure gauge 43 and the fiber Bragg grating displacement meter 44 are attached to the outer wall of the tunnel scale model 5;

[0039] This embodiment provides a model test device for monitoring tunnel segments. A vertical downward load is applied to a medium 2 via a loading system, and the load is transferred to a scaled tunnel model 5 via the medium 2 to simulate the effect of an upper load on the tunnel segments during actual construction. The scaled tunnel model 5 is monitored in real time by the fiber grating sensor of the monitoring system to obtain the critical load at which the scaled tunnel model 5 is damaged by the upper load. Based on this data, the critical load at which the prototype tunnel is damaged can be calculated. The model test results are used to predict possible problems so that necessary reinforcement measures and structural optimization can be taken before the formal construction process to ensure the safety and stability of the project.

[0040] In actual use, after completing the model test, the monitoring system can be reused and installed on the prototype tunnel to monitor the health status of the prototype tunnel during actual construction and operation.

[0041] In a specific embodiment, Figure 5 As shown, in order to simulate a prototype tunnel, the exterior of each of the segment ring scale models is divided by grooves 52 into three standard block areas B simulating standard blocks, one capping block area F simulating a capping block, and two adjacent block areas L simulating adjacent blocks;

[0042] In this embodiment, the tunnel scale model 5 includes seven segment ring scale models, such as Figure 4 As shown, the scaled models of adjacent segment rings are connected by longitudinal connecting bolts 51;

[0043] like Figure 2 As shown, the seven scaled segment ring models are numbered from left to right as the first scaled segment ring model 5A, the second scaled segment ring model 5B, ..., the seventh scaled segment ring model 5G. Fiber Bragg grating strain gauges 41 are mounted on the inner wall of each scaled segment ring model. Ten fiber Bragg grating strain gauges 41 are evenly attached to each scaled segment ring model.

[0044] The fiber Bragg grating inclinometer 42 is arranged on the side of the first pipe ring scale model 5A, the third pipe ring scale model 5C, the fourth pipe ring scale model 5D, the fifth pipe ring scale model 5E and the seventh pipe ring scale model 5G. In this embodiment, it can be arranged on Figure 5 On the capping block area F shown;

[0045] Fiber Bragg grating soil pressure gauges 43 are installed at the bottom of the first segment ring scale model 5A, the fourth segment ring scale model 5D, and the seventh segment ring scale model 5G, and at the top of the third segment ring scale model 5C and the fifth segment ring scale model 5E;

[0046] The fiber Bragg grating displacement meter 44 is arranged on the side of the second pipe segment ring scale model 5B, the third pipe segment ring scale model 5C, the fifth pipe segment ring scale model 5E and the sixth pipe segment ring scale model 5F. In this embodiment, the fiber Bragg grating displacement meter 44 is pasted on the area of the capping block area F close to the groove 52, or on the area of the adjacent block area L close to the groove 52.

[0047] In a specific embodiment, Figure 1 As shown, the loading system includes a control device 31, a loading device 32 and a pressing plate 33;

[0048] The pressure plate 33 is fixed to the loading device 32. The loading device 32 applies a load to the medium 2 via the pressure plate 33. The pressure plate 33 enables the load to be evenly applied to the medium 2. The loading device 32 is electrically connected to the control device 31. The control device 31 is capable of controlling the magnitude of the load applied by the loading device 32.

[0049] In this embodiment, if Figure 1 As shown, it also includes a frame 34, the loading device 32 is a servo hydraulic cylinder, the pressure plate 33 is fixed on the piston rod of the servo hydraulic cylinder, the loading device 32 is fixed on the frame 34, and the control device 31 is a computer.

[0050] In a specific embodiment, Figure 3 As shown, the monitoring system further includes a fiber Bragg grating demodulator 45 and a monitoring device 46;

[0051] The fiber Bragg grating demodulator 45 is connected to the fiber Bragg grating sensor, and is used to collect and analyze various data measured by the fiber Bragg grating sensor. The fiber Bragg grating demodulator 45 is connected to the monitoring device 46, and the monitoring device 46 is used to display the data analyzed by the fiber Bragg grating demodulator 45. In this embodiment, the monitoring device 46 is a computer.

[0052] In a specific embodiment, adjacent segment ring scale models are assembled with staggered seams. In this embodiment, Figure 2 As shown, the second segment ring scale model 5B, the fourth segment ring scale model 5D and the sixth segment ring scale model 5F are assembled by rotating 22.5° relative to the first segment ring scale model 5A, the third segment ring scale model 5C, the fifth segment ring scale model 5E and the seventh segment ring scale model 5G to simulate the actual assembly method of the prototype tunnel.

[0053] In a specific embodiment, the control device 31 can control the loading device 32 to load in stages;

[0054] In this embodiment, when conducting the model test, the similarity ratio between the scaled tunnel model 5 and the prototype tunnel is set at 1:12. The diameter of the segment ring of the prototype tunnel is 6000 mm, the thickness is 300 mm, and the width is 1200 mm. The scaled segment ring model of the scaled tunnel model 5 has a diameter of 500 mm, a thickness of 25 mm, and a width of 100 mm. The scaled segment ring model is cast from gypsum (other materials with physical properties similar to concrete may also be used). The scaled segment ring model has a groove 52 with a sector-shaped cross-section. The groove 52 has a depth of 5 mm and a central angle of 4° (the central angle may be 3°-5°). Adjacent scaled segment ring models are connected by longitudinal connecting bolts 51. Seven scaled segment ring models are assembled into the scaled tunnel model 5.

[0055] A certain amount of medium 2 is first placed in the model box 1. After reaching a calibrated thickness of 25 cm, the assembled tunnel scale model 5 is placed in it. The fiber grating sensor is then placed in the set position. The fiber grating sensor, fiber grating demodulator 45, and monitoring device 46 are connected and debugged. After debugging, the model box 1 is filled with medium 2 again until the height difference between the upper surface of the medium 2 in the model box 1 and the top of the tunnel scale model 5 reaches 25 cm. The control device 31 controls the loading device 32 to drive the pressure plate 33 to move until the pressure plate 33 contacts the medium 2. At this time, staged loading can be performed.

[0056] The loading system can load a maximum of 500 kN. The loading system is first loaded from 0 to 100 kN. The operator observes the various data measured by the fiber Bragg grating sensor after analysis by the fiber Bragg grating demodulator 45. If the data has no obvious fluctuation and no sudden change occurs, the system is loaded from 100 kN to 200 kN to check whether a sudden change occurs. If no sudden change occurs, the system continues loading until the data suddenly changes. At this time, the pipe segment is damaged, and the critical load for pipe segment damage is obtained. The operator can identify the structural defects of the prototype tunnel by checking the damage situation of the tunnel scale model 5, and thus take reinforcement measures and perform structural optimization before the formal construction process.

[0057] 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 deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A model test device for tunnel segment monitoring, characterized in that: include: loading systems, monitoring systems, and models; The model comprises a model box (1), a tunnel scale model (5) and a medium (2); the tunnel scale model (5) comprises a plurality of segment ring scale models connected in sequence; the outer periphery of the segment ring scale model is provided with a groove (52) for simulating the joints between the segments; The tunnel scale model (5) is placed horizontally in the model box (1); the outer periphery of the tunnel scale model (5) is surrounded by a medium (2); the medium (2) is capable of transmitting a load; the loading system is capable of applying a load to the medium (2); and the direction in which the loading system applies the load is vertically downward; The monitoring system includes a fiber Bragg grating sensor, which includes a fiber Bragg grating strain gauge (41), a fiber Bragg grating inclinometer (42), a fiber Bragg grating soil pressure gauge (43) and a fiber Bragg grating displacement meter (44); The fiber Bragg grating strain gauge (41) is arranged on the inner wall of the tunnel scale model (5), the fiber Bragg grating inclinometer (42) is arranged on the side of the tunnel scale model (5), the fiber Bragg grating soil pressure gauge (43) is arranged on the top and bottom of the tunnel scale model (5), and the fiber Bragg grating displacement meter (44) is arranged on the side of the tunnel scale model (5), and the fiber Bragg grating displacement meter (44) is located on the area of the segment ring scale model close to the groove (52).

2. A model test device for tunnel segment monitoring according to claim 1, characterized in that: The loading system includes a control device (31), a loading device (32) and a pressing plate (33); The pressure plate (33) is fixed on the loading device (32), and the loading device (32) applies a load to the medium (2) through the pressure plate (33). The control device (31) can control the size of the load applied by the loading device (32).

3. The model test device for tunnel segment monitoring according to claim 1, characterized in that: The monitoring system further includes a fiber Bragg grating demodulator (45) and a monitoring device (46); The fiber Bragg grating demodulator (45) is connected to the fiber Bragg grating sensor, and the fiber Bragg grating demodulator (45) is connected to the monitoring device (46).

4. A model test device for tunnel segment monitoring according to claim 2, characterized in that: The control device (31) can control the loading device (32) to load in stages.

5. The model test device for tunnel segment monitoring according to claim 1, characterized in that: The adjacent segment ring scale models are assembled with staggered joints.

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