A tunnel durability test device and test method

Abstract

The application discloses a tunnel durability test device, and relates to the field of underground structure durability test. An environmental box applies a simulated load to a scaled model of the tunnel, a water circulation device simulates the groundwater distribution in different periods in the real service of the tunnel, an ion concentration sensor detects the real-time concentration of ions in the water, a strain sensor detects the real-time change of the strain value on the side wall of the scaled model, and the durability of the tunnel under the coupling action of the environment and the load is measured through the change of the strain value and / or the ion concentration. When the durability of the tunnel is measured by using the test device, the scaled model is proportionally reduced according to the tunnel, and the environmental box simulates the change of the earth pressure and the underground water level around the tunnel. Therefore, the durability change of the tunnel in the real environment can be reflected through the durability of the scaled model, the tunnel durability detection process is simplified, the detection efficiency and accuracy are improved, and the development and utilization of urban underground space and the construction of a resilient city are promoted.

Description

Technical Field

[0001] This invention relates to the field of underground structure durability testing, and in particular to a tunnel durability testing device and method. Background Technology

[0002] Tunnel structures are subjected to the coupled effects of multiple environments and loads, including water and soil pressure and chemical corrosion, leading to significant durability degradation that directly impacts engineering safety and lifespan. However, there is currently a lack of dedicated testing equipment capable of simulating the actual service conditions of tunnels and realizing the long-term synergistic effect of environmental factors and mechanical loads on structural specimens. This makes it difficult to accurately reveal the damage evolution mechanism of tunnel structures under complex coupled effects.

[0003] Therefore, it is necessary to develop a tunnel structure durability testing device that can precisely control and couple the environment and load to promote the development and utilization of urban underground space and the construction of resilient cities. Summary of the Invention

[0004] The purpose of this invention is to provide a tunnel durability testing device and method to solve the problems existing in the prior art. It uses an environmental chamber to simulate the actual service state of a tunnel, intuitively showing the durability changes of the tunnel structure under complex coupling effects, and improving the measurement accuracy of the durability changes of the tunnel structure under the coupling effects of environment and mechanical loads.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a tunnel durability testing device, including a central processing system, a scaled-down model of the tunnel, and an environmental chamber for applying simulated loads to the scaled-down model. The scaled-down model is placed inside the environmental chamber, and strain sensors are arranged on the inner side of the scaled-down model. The strain sensors are evenly distributed along the circumference of the scaled-down model. A water circulation device is arranged on the environmental chamber, and an ion concentration sensor is arranged on the inner side of the environmental chamber. A drying device is arranged outside the environmental chamber and is connected to the environmental chamber. The strain sensors, ion concentration sensors, and drying device are electrically connected to the central processing system.

[0006] In one embodiment, a camera is also installed inside the scaled-down model, and the camera's monitoring range covers the inner surface of the scaled-down model.

[0007] In one embodiment, a ring-shaped loading system is provided on the inner side of the environmental chamber, with one end of the loading system abutting against the outer surface of the scaled model and the other end of the loading system connected to the inner side of the environmental chamber.

[0008] In one embodiment, the loading system includes a support and a loading device. The fixed end of the loading device is disposed on the side of the support facing the scaled-down model, the other side of the support is connected to the inner side of the environmental chamber, and the output end of the loading device abuts against the surface of the scaled-down model.

[0009] In one embodiment, the water circulation device includes an inlet tank and a drain tank. Valves are respectively provided at the outlet end of the inlet tank and the inlet end of the drain tank. The inlet end of the inlet tank and the outlet end of the drain tank are connected by a circulation pipe. A circulation water pump is provided on the circulation pipe and is electrically connected to the central processing system.

[0010] In one embodiment, the valve is a solenoid valve, which is electrically connected to the central processing system.

[0011] In one embodiment, a water level sensor is also provided on the inner side wall of the environmental chamber. At least two water level sensors are provided, and the two water level sensors are arranged vertically on the side wall of the environmental chamber. The two water level sensors include a high water level sensor and a low water level sensor. The high water level sensor is located at the top of the environmental chamber, and the low water level sensor is located at the bottom of the environmental chamber.

[0012] In one embodiment, reinforcing ribs are provided on the outer side of the environmental chamber, and the reinforcing ribs are staggered along the outer side of the environmental chamber.

[0013] A test method for a tunnel durability testing device, using the aforementioned tunnel durability testing device, includes the following steps: S1: On-site investigation to obtain a scaled-down model of the tunnel and the distribution of soil layers and groundwater around the tunnel; S2: Place the scaled-down model inside the environment box and use the environment box to simulate the compression of the tunnel by the soil layer; S3: Groundwater is injected into the environmental tank through a water circulation device to simulate the rise of groundwater level during the rainy season. The central processing system sets the corrosion time, and the ion concentration sensor detects the change in the concentration of erosion ions in the groundwater during the corrosion time period. The strain sensor detects the change in strain value on the scale model and the change in the concentration of erosion ions to determine the erosion of the tunnel by erosion ions during the corrosion time period. S4: After the corrosion period, the groundwater in the environmental tank is discharged through the water circulation device to simulate the drop in groundwater level. After the groundwater in the environmental tank is completely discharged, the central processing system starts the drying device. The central processing system sets the drying time to allow the salt substances in the remaining groundwater to crystallize. The strain sensor detects the change in strain value on the scale model to reflect the erosion of the tunnel by the salt substances crystallized in the concrete pores during the dry season. S5: Repeat steps S3 and S4 until the predetermined number of inlet and outlet water cycles is reached, at which point the test ends.

[0014] In one embodiment, in step S3, the ion concentration sensor transmits the ion concentration to the central processing system, which then plots a real-time ion concentration curve.

[0015] The present invention achieves the following technical effects compared to the prior art: The environmental chamber allows for the application of simulated loads to a scaled-down model of the tunnel, mimicking the pressure exerted by the surrounding soil layers on the tunnel's exterior under real-world conditions. The simulated load distribution around the scaled-down model corresponds to the soil pressure distribution around the tunnel. A water circulation system, connected to the interior of the chamber, simulates the distribution of groundwater at different stages of a tunnel's actual service life. Ion concentration sensors within the chamber detect real-time ion concentrations in the water, while strain sensors detect real-time changes in strain values ​​on the scaled-down model's sidewalls. These real-time strain values ​​and concentrations are transmitted to a central processing system, which records and plots curves showing the changes in strain values ​​on the model's sidewalls and ion concentration in the water over time. By analyzing changes in strain values ​​and ion concentration within the environmental chamber, the durability of the scaled-down model under the coupled effects of environmental and mechanical loads can be measured.

[0016] When measuring tunnel durability using the aforementioned experimental setup, a field survey is first required to obtain a scaled-down model of the tunnel and the distribution of soil and groundwater around it. An environmental chamber is used to simulate soil compression of the tunnel, while a water circulation and drying device simulates different groundwater levels during the dry and rainy seasons. During the simulated dry and rainy seasons, ion concentration sensors and strain sensors are used to detect changes in ion concentration in the water and strain values ​​on the sidewalls of the scaled-down model, respectively. Since the scaled-down model is proportionally reduced to the tunnel size, and the environmental chamber simulates changes in soil pressure and groundwater level around the tunnel, the durability changes of the scaled-down model can reflect the tunnel's durability changes in a real environment. This simplifies the tunnel durability testing process, improves testing efficiency and accuracy, and promotes the development and utilization of urban underground space and the construction of resilient cities. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the durability testing device in one embodiment of the present invention; Figure 2 This is a top view of the environmental chamber in the durability testing apparatus in one embodiment of the present invention; Figure 3 This is a schematic diagram of the internal structure of the environmental chamber in a durability testing apparatus according to one embodiment of the present invention; Figure 4This is a front view of the environmental chamber in the durability testing apparatus of one embodiment of the present invention; Figure 5 This is a schematic diagram of a scaled-down model in a durability testing apparatus according to one embodiment of the present invention; Figure 6 This is a schematic diagram of the loading system in a durability testing apparatus according to one embodiment of the present invention; Figure 7 This is a schematic diagram of the loading device in a durability testing apparatus according to one embodiment of the present invention.

[0019] The components include: 1. Environmental chamber; 2. Fan; 3. Drainage tank; 4. Inlet tank; 5. Circulation pipe; 6. Computer; 7. Ion concentration acquisition instrument; 8. Strain acquisition instrument; 9. Intelligent control system; 10. Ion concentration sensor; 11. High water level sensor; 12. Low water level sensor; 13. Reinforcing rib; 14. Loading system; 15. Scale model; 16. Sealing plate; 17. Loading device; 17-1. Fixing plate; 17-2. Adjusting plate; 17-3. Loading plate; 17-4. Spring; 17-5. Guide rod; 18. Middle connecting rod; 19. Bottom connecting rod; 20. Strain sensor; 21. Camera. Detailed Implementation

[0020] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a tunnel durability testing device and method to solve the problems existing in the prior art. It uses an environmental chamber to simulate the actual service state of a tunnel, intuitively showing the durability changes of the tunnel structure under complex coupling effects, and improving the measurement accuracy of the durability changes of the tunnel structure under the coupling effects of environmental and mechanical loads.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Please refer to Figures 1 to 7In this embodiment, a tunnel durability testing device is provided, in which a scaled-down model 15 of the tunnel is set in the environmental chamber 1. Simulated loads are applied to the scaled-down model 15 through the environmental chamber 1. Under the action of the simulated loads, the scaled-down model 15 produces the same deformation or cracks as the tunnel, thus simulating the loads exerted on the tunnel by the surrounding soil layers in a real environment. A water circulation device is installed on the environmental chamber 1 to simulate the groundwater around the tunnel in a real environment. To ensure that the simulated environment is as close as possible to the real environment where the tunnel is located, in this embodiment, the solution circulated by the water circulation device is the groundwater at the location of the tunnel. The water circulation device and the environment... The environmental chamber 1 is connected, and the presence and level of water in the environmental chamber 1 are controlled by a water circulation device. During the durability test, after the environmental chamber 1 applies a simulated load to the scaled model 15, groundwater is injected into the environmental chamber 1 through the water circulation device. The water injection process simulates the rise in groundwater level caused by the rainy season. The scaled model 15 is completely or partially immersed in the groundwater. The groundwater level can be adjusted according to the actual situation. After injecting groundwater into the environmental chamber 1, a corrosion time is set, which is the time that the scaled model 15 is immersed in the groundwater. During the corrosion time, the corrosive ions (such as Cl-) contained in the groundwater are measured. - SO4 2- Chemical corrosion occurs when corrosive ions enter the cracks of the scaled model 15, causing tiny cracks to form on its surface. An ion concentration sensor 10 is installed in the environmental chamber 1 to detect the concentration of corrosive ions in the chamber and transmits the real-time ion concentration to the central processing system. As time progresses, the concentration of corrosive ions in the environmental chamber 1 gradually decreases. The central processing system plots a curve showing the change in ion concentration over time based on the real-time ion concentration. The test personnel can judge the durability of the scaled model 15 by observing the changes in the concentration of corrosive ions. Strain sensors 20 are also installed on the inner side of the scaled model 15. The strain sensors 20 are evenly distributed around the circumference of the scaled model 15. When the simulated load is applied and during the corrosion period, the strain sensors 20 detect the strain changes on the sidewall of the scaled model 15 in real time and transmit the real-time strain changes to the central processing system. The central processing system plots a curve showing the change in strain over time and judges the durability of the scaled model 15 under the coupled effects of environment and load by observing the changes in strain.

[0024] After corrosion, the groundwater in environmental chamber 1 is drained through a water circulation device, and the interior of environmental chamber 1 is dried by a drying device. Preferably, a fan 2 is used as the drying device. This causes the salts remaining on the outer surface and in the cracks of the scale model 15 to crystallize. The volume of the ettringite, a chemical product of sulfate corrosion, expands, causing the tiny cracks to expand and connect, further forming macroscopic cracks. The strain changes on the sidewall of the scale model 15 are detected by a strain sensor 20 installed inside the scale model 15. The strain sensor 20 transmits the detected real-time strain to the central processing system. The central processing system can plot the strain-time curve based on the real-time strain of the scale model 15. The test personnel can judge the durability of the scale model 15 under the coupled action of environment and load by the strain change.

[0025] In another embodiment, the solution circulated by the water circulation device can also be a simulated solution prepared by the test personnel according to the composition of the groundwater in the tunnel location during the test. During the preparation process, the concentration of corrosive ions in the solution entering the environmental chamber 1 is detected by an ion concentration sensor so that the simulated solution can restore the groundwater in the tunnel environment as much as possible.

[0026] Preferably, to prevent groundwater from entering the scaled-down model 15, sealing plates 16 are provided at both ends of the scaled-down model 15.

[0027] In this embodiment, the central processing system includes a computer 6, an ion concentration acquisition instrument 7, an intelligent control system 9, and a strain acquisition instrument 8. The ion concentration acquisition instrument 7, intelligent control system 9, and strain acquisition instrument 8 are all electrically connected to the computer 6. The ion concentration acquisition instrument 7 converts the signal uploaded by the ion concentration sensor 10 into an electrical signal and transmits it to the computer 6. The computer 6 stores the real-time ion concentration and plots a curve showing the change in ion concentration over time. The intelligent control system 9 is electrically connected to the water circulation system and the drying device. The intelligent control system 9 automatically controls the water injection and drainage times of the water circulation system and the drying time of the drying device, reducing manual intervention and saving manpower. The strain sensor 20 is electrically connected to the computer 6 via the strain acquisition instrument 8. The computer 6 stores the real-time strain value and plots the real-time strain value as a curve showing its change over time. The ion concentration change curve and the strain value change curve can be displayed on a monitor. Furthermore, during the experiment, the experimenter can use the computer 6 to debug each instrument to ensure the smooth progress of the experiment.

[0028] In this embodiment, in order to more intuitively observe the changes in the inner wall of the scaled model 15 after the durability of the scaled model 15 decreases, a camera 21 is also installed inside the scaled model 15. At least one camera 21 is installed, and the monitoring range of the camera 21 is ensured to cover the entire inner side of the scaled model 15. The camera 21 is connected to the computer 6 in the central processing system. The test personnel can intuitively observe the changes in cracks and water leakage on the inner wall of the scaled model 15 through the display of the computer 6.

[0029] The environment box 1 serves to simulate the real environment around the tunnel. In this embodiment, a ring-shaped loading system 14 is provided on the inner side of the environment box 1. One end of the loading system 14 abuts against the outer surface of the scale model 15, and the other end is connected to the inner side of the environment box 1. The pressure on the surface of the scale model 15 can be changed through the loading system 14. The loading system 14 simulates the squeezing force of the soil layer around the tunnel on it.

[0030] The loading system 14 includes a support member and a loading device 17. One end of the support member is set on the inner wall of the environmental box 1, and the other end is set with the loading device 17. The loading device 17 is abutted against the surface of the scale model 15 to simulate the load applied by the soil layer to the tunnel. Since the soil layer around the tunnel is not uniformly distributed, the support member is rotatably connected to the inner wall of the environmental box 1. This allows the abutment position of the loading device 17 against the surface of the scale model 15 to be changed according to the actual distribution of the soil layer around the tunnel, ensuring that the distribution position of the simulated load around the scale model 15 is consistent with the distribution position of the soil layer in the real environment of the tunnel. Preferably, the support rod includes a middle connecting rod 18 and a bottom connecting rod 19. The middle connecting rod 18 and the bottom connecting rod 19 are connected by a hinge support, which changes the abutment position of the loading system 14 against the surface of the scale model 15.

[0031] The loading device 17 includes, but is not limited to, electric telescopic rods, elastic elements, and other devices that can change the pressure applied by the loading system 14 to the scaled model 15.

[0032] Preferred, Reference Figure 7The loading device 17 includes a loading plate 17-3, an adjusting plate 17-2, and a fixed plate 17-1. A guide rod 17-5 is provided on the fixed plate 17-1, and a sleeve is sleeved on the guide rod 17-5. The adjusting plate 17-2 is sleeved on the sleeve and can slide freely along the axial direction of the sleeve. The loading plate 17-3 is provided at the end of the sleeve away from the fixed plate 17-1. A spring 17-4 is provided between the loading plate 17-3 and the adjusting plate 17-2. The loading plate 17-3 abuts against the surface of the scaled model 15. When the adjusting plate 17-2 moves towards the scaled model 15... By compressing the spring 17-4 to change its deformation, the compressive force between the loading plate 17-3 and the scale model 15 is adjusted, thereby simulating the pressure of the soil layer around the tunnel on the tunnel in the real environment. In order to control the movement of the adjusting plate 17-2 towards or away from the scale model 15, a threaded hole is provided on the fixing plate 17-1, and a bolt is provided in the threaded hole. The end of the bolt facing the adjusting plate 17-2 abuts against the adjusting plate 17-2. By rotating the bolt, the adjusting plate 17-2 is controlled to move closer to the scale model 15 to compress the spring 17-4, or to move away from the scale model 15 under the elastic force of the spring 17-4.

[0033] In this embodiment, the water circulation device includes an inlet tank 4 and a drain tank 3. The inlet tank 4 contains groundwater from the environment where the tunnel is located. Valves are installed at the outlet of the inlet tank 4 and the inlet of the drain tank 3. During a simulated rainy season, the valve at the inlet of the drain tank 3 is closed, and the valve at the outlet of the inlet tank 4 is opened, allowing the groundwater in the inlet tank 4 to flow into the environmental tank 1. The water level in the environmental tank 1 is controlled by the valve at the outlet of the inlet tank 4. Once the water level in the environmental tank 1 reaches a predetermined height, the valve at the outlet of the inlet tank 4 is closed, maintaining the water level in the environmental tank 1 at the predetermined height for a certain period of time (i.e., After the corrosion period, the valve on the inlet of the drainage tank 3 is opened to drain the groundwater in the environmental tank 1, simulating the drop in groundwater level around the tunnel under dry season conditions, until the groundwater in the environmental tank 1 is completely drained. The inlet tank 4 and the drainage tank 3 are connected by a circulation pipe 5, which is equipped with a circulation pump. The circulation pump is electrically connected to the intelligent control system 9 in the central processing system. After the groundwater in the environmental tank 1 is drained to the drainage tank 3, the central processing system starts the circulation pump to transport the groundwater in the drainage tank 3 to the inlet tank 4, preparing for the next simulated rainy season environment.

[0034] Preferably, the inlet of the water inlet tank 4 is located at the top of the environmental tank 1, and the outlet of the drainage tank 3 is located at the bottom of the environmental tank 1, so that groundwater can be injected into and discharged from the environmental tank 1 under the action of the height difference, eliminating the need to install a pumping device in the environmental tank 1 and avoiding the vibration generated by the pumping device from affecting the strain change of the side wall of the scaled model 15.

[0035] To improve the automation of the experimental setup and reduce the workload of the personnel, the valves at the outlet of the inlet tank 4 and the inlet of the outlet tank 3 are solenoid valves. For ease of description, the solenoid valve at the outlet of the inlet tank 4 is referred to as the first solenoid valve, and the solenoid valve at the inlet of the outlet tank 3 is referred to as the second solenoid valve. The first and second solenoid valves are electrically connected to the intelligent control system 9. When it is necessary to inject groundwater into the environmental tank 1, the intelligent control system 9 controls the second solenoid valve to close and controls the first solenoid valve to open until the water level in the environmental tank 1 reaches the predetermined height. Then, it controls the first solenoid valve to close, stopping the injection of groundwater into the environmental tank 1. After the groundwater stays in the environmental tank 1 for a certain period of time (i.e., the corrosion time), the intelligent control system 9 controls the second solenoid valve to open until all the groundwater in the environmental tank 1 is discharged into the outlet tank 3. At this time, the intelligent control system 9 starts the circulating water pump to transport the groundwater in the outlet tank 3 to the inlet tank 4, preparing for the subsequent injection of groundwater into the environmental tank 1.

[0036] During the process of injecting groundwater into the environmental tank 1, in order to ensure that the water inlet tank 4 and the water outlet tank 3 in the water circulation device can automatically complete the water inlet and outlet operations, a water level sensor is also installed on the inner side wall of the environmental tank 1. In this embodiment, at least two water level sensors are installed, and the two water level sensors are installed vertically on the side wall of the environmental tank 1. The two water level sensors are respectively installed at the top and bottom of the environmental tank 1. The water level sensor installed at the top of the environmental tank 1 is the high water level sensor 11, and the water level sensor installed at the bottom of the environmental tank 1 is the low water level sensor 12. The high water level sensor 11 and the low water level sensor 12 are electrically connected to the intelligent control system 9.

[0037] When groundwater is injected into environmental tank 1, the water level reaches the high water level sensor 11. The high water level sensor 11 sends a high water level signal to the intelligent control system 9, and the intelligent control system 9 closes the first solenoid valve. When the groundwater in environmental tank 1 is discharged, the intelligent control system 9 opens the second solenoid valve. As the water volume in environmental tank 1 decreases, the water level reaches the low water level sensor 12. The low water level sensor 12 sends a low water level signal to the intelligent control system 9, and the intelligent control system 9 closes the second solenoid valve. At this time, it indicates that the groundwater in environmental tank 1 has been completely discharged.

[0038] In another embodiment, when simulating a rainy season environment, the groundwater level is affected by the amount of rainfall. Therefore, in the process of simulating a tunnel using a scaled model 15, a first water level sensor and a second water level sensor are set between the high water level sensor 11 and the low water level sensor 12. The first water level sensor is set at one-third of the height of the inner wall of the environmental chamber 1, and the second water level sensor is set at two-thirds of the height of the inner wall of the environmental chamber 1. The first water level sensor and the second water level sensor are used to control the groundwater in the environmental chamber 1 to be at different water levels, thereby achieving a simulation test that conforms to the real environment.

[0039] In this test apparatus, the pressure exerted on the tunnel by the surrounding soil layer is simulated by the environmental chamber 1. To ensure the stability of the environmental chamber 1 structure, reinforcing ribs 13 are provided on the outer side of the environmental chamber 1. The reinforcing ribs 13 are staggered along the outer side of the environmental chamber 1 to improve the structural strength of the sidewall of the environmental chamber 1.

[0040] Preferably, the reinforcing ribs 13 are staggered at 90 degrees on the outer side wall of the environmental chamber 1.

[0041] This embodiment also discloses a test method for a tunnel durability testing device, which includes the following steps when using the aforementioned tunnel durability testing device: S1: On-site investigation to obtain a scaled-down model 15 of the tunnel and the distribution of soil layers and groundwater around the tunnel; S2: Assemble the environment-load coupling test device; place the scaled model 15 inside the environment box 1, and the loading device 17 of the loading system 14 abuts against the surface of the scaled model 15. The loading device 17 is used to change the pressure between the loading system 14 and the scaled model 15, thereby simulating the load generated by soil layers in different directions on the tunnel. S3: The intelligent control system 9 controls the water inlet tank 4 to inject groundwater into the environmental tank 1, simulating the rise of groundwater level in the tunnel during the rainy season. After reaching the predetermined water level, the water level sensor at the corresponding position sends a signal to the intelligent control system 9 to stop water injection, and the groundwater is left in the environmental tank 1 for a period of time (i.e., corrosion time). During the corrosion time, the ion concentration sensor 10 detects the change in the concentration of corrosive ions in the groundwater. The lower the concentration of corrosive ions, the more the corrosive ions gradually increase the degree of corrosion of the scale model 15, and the lower the durability of the scale model 15. The strain sensor 20 detects the strain value of the scale model 15. The change in the strain value on the scale model 15 reflects the magnitude of its deformation under the coupled action of environment and load. The increase in strain value represents the decrease in the durability of the scale model 15. During the simulation of the rainy season, the changes in the concentration of corrosive ions and the changes in the strain value reflect the durability of the scale model 15 during the corrosion time. S4: After the corrosion time, the intelligent control system 9 opens the electromagnetic valve at the inlet of the drainage tank 3 to drain the groundwater in the environmental tank 1 to the drainage tank 3, simulating the drop in groundwater level in the tunnel during the dry season. After the groundwater in the environmental tank 1 is completely drained, the intelligent control system 9 starts the drying device and sets the drying time to allow the salts in the groundwater remaining on the surface of the scale model 15 to crystallize. The strain sensor 20 detects the strain changes on the scale model 15 to reflect the erosion of the tunnel by the salts in the concrete cracks during the dry season. S5: Repeat steps S3 and S4 until the predetermined number of inlet and outlet water cycles is reached, at which point the test ends.

[0042] Preferably, in step S3, the ion concentration sensor 10 transmits the ion concentration to the central processing system, and the central processing system plots a real-time ion concentration curve.

[0043] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0044] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A tunnel durability testing device, characterized in that, The system includes a central processing system, a scaled-down model (15) of the tunnel, and an environmental chamber (1) for applying simulated loads to the scaled-down model (15). The scaled-down model (15) is located inside the environmental chamber (1). Strain sensors (20) are provided on the inner side of the scaled-down model (15). The strain sensors (20) are evenly distributed along the circumference of the scaled-down model (15). A water circulation device is provided on the environmental chamber (1). An ion concentration sensor (10) is provided on the inner side of the environmental chamber (1). A drying device is provided on the outside of the environmental chamber (1). The drying device is connected to the environmental chamber (1). The strain sensors (20), the ion concentration sensors (10), and the drying device are electrically connected to the central processing system.

2. The tunnel durability testing device according to claim 1, characterized in that, The scaled-down model (15) is also equipped with a camera (21), the monitoring range of which covers the inner surface of the scaled-down model (15).

3. The tunnel durability testing device according to claim 1, characterized in that, The inner side of the environmental chamber (1) is provided with a ring-shaped loading system (14). One end of the loading system (14) abuts against the outer surface of the scaled model (15), and the other end of the loading system (14) is connected to the inner side of the environmental chamber (1).

4. The tunnel durability testing device according to claim 3, characterized in that, The loading system (14) includes a support and a loading device (17). The fixed end of the loading device (17) is located on the side of the support facing the scaled model (15), and the other side of the support is connected to the inner side of the environmental box (1). The output end of the loading device (17) abuts against the surface of the scaled model (15).

5. The tunnel durability testing device according to claim 1, characterized in that, The water circulation device includes an inlet tank (4) and a drain tank (3). The outlet end of the inlet tank (4) and the inlet end of the drain tank (3) are respectively equipped with valves. The inlet end of the inlet tank (4) and the outlet end of the drain tank (3) are connected by a circulation pipe (5). A circulation water pump is installed on the circulation pipe (5). The circulation water pump is electrically connected to the central processing system.

6. The tunnel durability testing device according to claim 5, characterized in that, The valve is a solenoid valve, and the solenoid valve is electrically connected to the central processing system.

7. The tunnel durability testing device according to claim 1, characterized in that, A water level sensor is also provided on the inner wall of the environmental tank (1). At least two water level sensors are provided, and the two water level sensors are arranged vertically on the side wall of the environmental tank (1). The two water level sensors include a high water level sensor (11) and a low water level sensor (12). The high water level sensor (11) is located at the top of the environmental tank (1), and the low water level sensor (12) is located at the bottom of the environmental tank (1).

8. The tunnel durability testing device according to claim 1, characterized in that, The outer side of the environmental chamber (1) is provided with reinforcing ribs (13), and the reinforcing ribs (13) are staggered along the outer side of the environmental chamber (1).

9. A test method for the tunnel durability testing device as described in claim 1, characterized in that, Includes the following steps: S1: On-site investigation to obtain a scaled model of the tunnel (15) and the distribution of soil layers and groundwater around the tunnel; S2: Place the scaled-down model (15) inside the environmental box (1) and use the environmental box (1) to simulate the compression of the tunnel by the soil layer; S3: Groundwater is injected into the environmental tank (1) through the water circulation device to simulate the rise of groundwater level during the rainy season. The central processing system sets the corrosion time. The ion concentration sensor (10) detects the change of erosion ion concentration in groundwater during the corrosion time period. The strain sensor (20) detects the change of strain value and erosion ion concentration on the scale model (15) to determine the erosion of the tunnel by erosion ions during the corrosion time period. S4: After corrosion time, the groundwater in the environmental tank (1) is discharged through the water circulation device to simulate the drop in groundwater level. After the groundwater in the environmental tank (1) is completely discharged, the central processing system starts the drying device. The central processing system sets the drying time to allow the salt substances in the residual groundwater to crystallize. The strain sensor (20) detects the change in strain value on the scale model (15) to reflect the erosion of the tunnel by the salt substances crystallized in the concrete pores during the dry season. S5: Repeat steps S3 and S4 until the predetermined number of inlet and outlet water cycles is reached, at which point the test ends.

10. The test method according to claim 9, characterized in that, In step S3, the ion concentration sensor (10) transmits the ion concentration to the central processing system, which plots a real-time ion concentration curve.

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