An experimental device for observing crack propagation in tunnel linings simulating a dynamic water environment

Abstract

The present invention discloses an observation experimental device for tunnel lining crack expansion simulating a dynamic water environment, belonging to the field of tunnel lining crack observation, including a simulation experiment box, a test piece is arranged in the simulation experiment box, the test piece includes a surrounding rock layer, a concrete lining test block with prefabricated cracks is arranged under the surrounding rock layer, a pressure simulation mechanism is arranged at the top and both sides of the simulation experiment box, a number of strain gauges are evenly arranged on the concrete lining test block, a lifting and translation assembly is arranged at the top of the simulation experiment box, and the lifting and translation assembly is connected to the crack expansion observation mechanism through a telescopic element. The present invention adopts the above-mentioned experimental device, simulates the pressure load on the tunnel lining through the pressure simulation mechanism, simulates the water pressure in different directions and different flow rates through the crack expansion observation mechanism, and monitors the expansion of the tunnel lining cracks in real time, which plays an important role in the disease analysis and repair and maintenance of the tunnel lining.

Description

Technical Field

[0001] The invention relates to the technical field of lining crack observation, in particular to an observation experimental device for tunnel lining crack expansion simulating a dynamic water environment. Background Art

[0002] Tunnel lining refers to a permanent structure that supports and maintains the long-term stability and durability of the tunnel. Its functions are: to support and maintain the stability of the tunnel; to maintain the space required for train operation; to prevent weathering of the surrounding rock; to eliminate the influence of groundwater, etc. Therefore, the tunnel lining must have sufficient strength, durability, and certain anti-freeze, anti-seepage and anti-corrosion properties. The tunnel lining is mainly composed of arch rings, side walls, inverts and bottom plates.

[0003] Tunnel lining generally adopts reinforced concrete structure. The tunnel lining construction is completed by laying steel mesh along the surrounding rock and pouring concrete. Tunnel lining will produce cracks during long-term use. Due to the influence of groundwater, the lining cracks will continue to expand. Especially in southern my country, the expansion of tunnel lining cracks in water-rich environment is more complicated. The water environment around the tunnel lining is a dynamic water environment. The lining cracks are often subjected to the pressure of water in different directions and different flow rates. The water quality is complex, not only containing sediment particles but also rich chemical elements, which have a greater impact on the expansion of lining cracks. Under the action of long-term, groundwater chemicals (mainly sulfates, carbonates, etc.) will cause serious erosion to the lining structure and the internal steel bars of the lining. The potassium, sodium, and magnesium sulfates in the environmental water replace the calcium hydroxide in the cement stone to form calcium sulfate. Calcium sulfate reacts with the hydrated calcium aluminate generated by the hydration of cement clinker minerals to form high-sulfur hydrated calcium sulfoaluminate, commonly known as calcium rock stone. The solubility of calcium rock stone is extremely low. The crystallization pressure caused by the growth of precipitated crystals causes the concrete to expand and crack. Therefore, the erosion of chemical substances in groundwater will cause serious damage to the erosion of concrete. The tunnel lining will produce cracks due to pressure after long-term use, and the cracks will expand faster in a dynamic water environment. At present, there is still a blank in the observation experiment of the expansion of tunnel lining cracks in a dynamic water environment. It is of great significance for the disease analysis and repair and maintenance of tunnel linings to simulate the expansion of lining cracks in a dynamic water environment and observe and monitor them. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an observation experimental device for tunnel lining crack expansion simulating a dynamic water environment. The pressure load on the tunnel lining is simulated by a pressure simulation mechanism, and the water pressure in different directions and at different flow rates is simulated by a crack expansion observation mechanism. The expansion of the tunnel lining cracks is monitored in real time, which plays an important role in the disease analysis and repair and maintenance of the tunnel lining.

[0005] To achieve the above-mentioned purpose, the present invention provides an observation experiment device for tunnel lining crack expansion simulating a dynamic water environment, comprising a simulation experiment box, a test piece is arranged in the simulation experiment box, the test piece includes a surrounding rock layer, a concrete lining test block with prefabricated cracks is arranged under the surrounding rock layer, a pressure simulation mechanism is arranged at the top and both sides of the simulation experiment box, a plurality of strain gauges are evenly arranged on the concrete lining test block, a lifting and translation assembly is arranged at the top of the simulation test box, the lifting and translation assembly is connected to the crack expansion observation mechanism through a telescopic element, the crack expansion observation mechanism includes a mounting plate, a water pump is arranged on the inner side of the mounting plate, an observation frame is connected to the outer side of the mounting plate, observation cameras are arranged on both sides of the observation frame, a plurality of water outlets are arranged in the middle of the observation clamp, and the water pump is connected to the water outlets.

[0006] Preferably, a tunnel foundation surface is provided at the bottom layer in the simulation experiment box, and the tunnel foundation surface is connected to the surrounding rock layer and the bottom end of the concrete lining test block.

[0007] Preferably, the crack observation mechanism is arranged inside the simulation experiment box, one end of the water pump is connected to a water inlet pipe, a flow sensor is arranged on the water inlet pipe, the other end of the water pump is connected to the water outlet through the water outlet pipe, a universal pipe head is arranged on the water outlet, the outlet of the universal pipe head is connected to the water pipe head with a flow sensor and a water pressure sensor, and the observation camera and the water outlet are both arranged on the mounting plate.

[0008] Preferably, the lifting and translation assembly includes a double-screw translation structure, a waterproof box 1 is arranged below the double-screw translation structure, an electric hydraulic cylinder is arranged in the waterproof box 1, the hydraulic rod of the electric hydraulic cylinder is connected to the waterproof box 2, the telescopic element is an electric hydraulic cylinder, the telescopic element is arranged in the waterproof box 2, the hydraulic rod of the telescopic element is connected to the mounting plate, and the waterproof box 2 is connected to the mounting plate through a guide structure.

[0009] Preferably, the guide structure includes symmetrically arranged guide tubes, which are arranged on both sides of the waterproof box 2. A guide rod is slidably arranged in the guide tube, one end of the guide rod is connected to the inner side of the mounting plate, and a limiting block is arranged at the other end of the guide rod.

[0010] Preferably, the double screw translation structure includes screw 1 and screw 2, and moving blocks are mounted on screw 1 and screw 2. The bottom end of the moving block is connected to waterproof box 1, one end of screw 1 is connected to the output shaft of motor 1, and the other end of screw 1 is connected to the bearing, one end of screw 2 is connected to the output shaft of motor 2, and the other end of screw 2 is connected to the bearing.

[0011] Preferably, a circular water tank is provided at the top of the simulation experiment box, and the circular water tank is connected with the interior of the simulation experiment box through a pipeline, and an electronic valve is provided on the pipeline.

[0012] Preferably, the pressure simulation mechanism includes a plurality of hydraulic cylinders 1 and a plurality of hydraulic cylinders 2, wherein hydraulic cylinder 1 is arranged in the middle of the concave water tank, and hydraulic cylinder 2 is arranged on both sides of the simulation experiment box, and the hydraulic rod of hydraulic cylinder 1 and the hydraulic rod of hydraulic cylinder 2 are connected with a pressure applying head.

[0013] Preferably, a drain port is provided on the simulation experiment box, and a sealing cover is provided on the drain port.

[0014] The present invention has the following beneficial effects:

[0015] The present invention simulates the pressure load that the tunnel lining is subjected to in the actual environment through a pressure simulation mechanism, can drive the crack expansion observation mechanism to lift and translate through a lifting and translation component, and drives the crack expansion observation mechanism to extend forward to align with the prefabricated cracks in the tunnel lining through a telescopic element, simulates water pressures in different directions and at different flow rates through the crack expansion observation mechanism, and conducts real-time and comprehensive monitoring of the crack expansion of the tunnel lining through a high-definition observation camera, which plays an important role in the disease analysis and repair and maintenance of the tunnel lining.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the internal structure of a simulation experiment box according to an embodiment of the present invention;

[0019] Figure 3 A side view of a test piece according to an embodiment of the present invention;

[0020] Figure 4 A side view of a double screw structure according to an embodiment of the present invention;

[0021] Figure 5 A top view of a double screw structure according to an embodiment of the present invention;

[0022] Figure 6 A schematic diagram of a crack extension observation mechanism according to an embodiment of the present invention;

[0023] Figure 7 Schematic diagram of the outer side of the mounting plate according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 1. Simulation experiment box; 2. Surrounding rock layer; 3. Concrete lining test block; 4. Strain gauge; 5. Tunnel foundation surface; 6. Hydraulic cylinder one; 7. Hydraulic cylinder two; 8. Pressure application head; 9. Convex water tank; 10. Protective cover; 11. Screw one; 12. Screw two; 13. Motor one; 14. Motor two; 15. Bearing; 16. Moving block; 17. Waterproof box one; 18. Waterproof box two; 19. Mounting plate; 20. Guide tube; 21. Guide rod; 22. Water pump; 23. Water outlet; 24. Observation camera; 25. Observation stand. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0027] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0028] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0030] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1 As shown, the observation experiment device for tunnel lining crack extension in a simulated water environment of the present invention comprises a simulation experiment box 1, in which a test piece is arranged. Figure 2 , Figure 3 As shown, the specimen includes a surrounding rock layer 2, and a concrete lining test block 3 with prefabricated cracks is arranged under the surrounding rock layer 2. A tunnel foundation surface 5 is arranged at the bottom layer in the simulation experiment box 1, and the tunnel foundation surface 5 is connected to the bottom end of the surrounding rock layer 2 and the concrete lining test block 3. A circular water tank 9 is arranged at the top of the simulation experiment box 1, and the circular water tank 9 is connected to the inside of the simulation experiment box 1 through a pipeline, and an electronic valve is arranged on the pipeline. A drain port is arranged on the simulation experiment box 1, and a sealing cover is arranged in the drain port, and the sealing cover is sealed and connected to the drain port through a thread. The circular water tank 9 can add water to the simulation experiment box 1 through a pipeline, and the "water" in the circular water tank 9 is groundwater with chemical substances that simulates the real environment.

[0032] Several strain gauges 4 are evenly distributed on the concrete lining test block 3, such as Figure 2 As shown, the top and both sides of the simulation experiment box 1 are provided with pressure simulation mechanisms, which include a plurality of hydraulic cylinders 1 6 and a plurality of hydraulic cylinders 2 7. The hydraulic cylinder 1 6 is provided in the middle of the roundabout water tank 9, and the hydraulic cylinder 2 7 is provided on both sides of the simulation experiment box 1. The hydraulic rods of the hydraulic cylinder 1 6 and the hydraulic rods of the hydraulic cylinder 2 7 are connected with a pressure applying head 8. The hydraulic cylinder 1 6 and the hydraulic cylinder 2 7 are electric hydraulic cylinders. The hydraulic rod of the hydraulic cylinder 1 6 drives the pressure applying head 8 to press down, and applies downward pressure to the top of the surrounding rock layer 2. The hydraulic rod of the hydraulic cylinder 2 7 drives the pressure applying head 8 to move toward the middle, and applies lateral pressure to both sides of the surrounding rock layer 2, simulating the pressure load on the tunnel lining in the actual environment. Through multiple hydraulic cylinders 1 6 and 2 7, different pressure simulations can be achieved in different areas of the surrounding rock layer 2. The deformation of the tunnel lining is monitored in real time through the strain gauge 4, and the application of pressure is adjusted, thereby simulating a more realistic stress condition of the tunnel lining, so that the subsequent expansion of the tunnel lining cracks is more in line with the actual situation.

[0033] The top of the simulation test box is provided with a lifting and translation assembly, and a protective cover 10 is provided on the lifting and translation assembly. The lifting and translation assembly is connected to the crack extension observation mechanism through a telescopic element, and the crack extension observation mechanism includes a mounting plate 19. Figure 4 , Figure 5 As shown, the lifting and translation assembly includes a double-screw translation structure, and the double-screw translation structure includes a screw 11 and a screw 2 12, and a moving block 16 is sleeved on the screws 11 and 12. The moving block 16 is provided with two threaded holes, and the screws 11 and 12 are respectively arranged in the two threaded holes of the moving block 16, and are threadedly connected to the moving block 16. The bottom end of the moving block 16 is connected to the waterproof box 17, one end of the screw 11 is connected to the output shaft of the motor 13, and the other end of the screw 11 is connected to the bearing 15. One end of the screw 2 12 is connected to the output shaft of the motor 2 14, and the other end of the screw 2 12 is connected to the bearing 15. An electric hydraulic cylinder is arranged in the waterproof box 17, and the hydraulic rod of the electric hydraulic cylinder is connected to the waterproof box 2 18. The telescopic element is an electric hydraulic cylinder, and the telescopic element is arranged in the waterproof box 2 18, and the hydraulic rod of the telescopic element is connected to the mounting plate 19. The waterproof box 2 18 is connected to the mounting plate 19 through a guide structure. As shown Figure 6 As shown, the guide structure includes symmetrically arranged guide tubes 20, which are arranged on both sides of the waterproof box 18. A guide rod 21 is slidably arranged in the guide tube 20, one end of the guide rod 21 is connected to the inner side of the mounting plate 19, and a limit block is arranged at the other end of the guide rod 21, which can prevent the guide rod 21 from falling off from the guide tube 20. The lead screw 11 and the lead screw 2 12 of the double screw translation structure are driven to rotate by the output shafts of the motor 1 13 and the motor 2 14 respectively, so that the moving block 16 is translated along the lead screw. The bottom end of the moving block 16 translates at the opening of the simulation experiment box 1, thereby driving the waterproof box 1 17 in the simulation experiment box 1 to translate, and the translation of the waterproof box 1 17 drives the translation of the waterproof box 2 18, thereby driving the translation of the crack observation mechanism. The hydraulic rod of the hydraulic cylinder 1 6 in the waterproof box 17 drives the waterproof box 2 18 to rise and fall, and the lifting of the waterproof box 2 18 can drive the lifting of the crack observation mechanism, thereby realizing the left and right translation and up and down lifting movement of the crack observation mechanism. The hydraulic rod of the hydraulic cylinder 27 in the waterproof box 218 drives the mounting plate 19 of the crack observation mechanism to extend or retract, so that the crack observation mechanism can be extended to the front end of the prefabricated crack of the tunnel lining to perform a simulation experiment.

[0034] The crack observation mechanism is arranged inside the simulation experiment box 1. Figure 6 , Figure 7As shown, a water pump 22 is arranged on the inner side of the mounting plate 19, and an observation frame 25 is connected to the outer side of the mounting plate 19. Observation cameras 24 are arranged on both sides of the observation frame 25, and a plurality of water outlets 23 are arranged in the middle of the observation clamp, and the water pump 22 is connected to the water outlets 23. One end of the water pump 22 is connected to a water inlet pipe, and a flow sensor is arranged on the water inlet pipe. The other end of the water pump 22 is connected to the water outlet 23 through the water outlet pipe, and a universal pipe head is arranged on the water outlet 23. The outlet of the universal pipe head is connected to a water pipe head with a flow sensor and a water pressure sensor, and the observation camera 24 and the outlet are both arranged on the mounting plate 19. The outlet of the water outlet pipe is connected to five branch pipes, and the five branch pipes are respectively connected to five water outlets 23. After the crack observation mechanism is translated and lifted, the mounting plate 19 extends forward so that the observation frame 25 lightly touches the surface of the tunnel lining, and the water pipe head of the water outlet 23 is located at the front end of the prefabricated crack of the lining. The water pump 22 draws water into the simulation test box 1 through the water inlet pipe, and then passes through the outlet pipe, branch pipe, outlet 23, universal pipe head, and finally discharges it from the water pipe head to simulate the dynamic water environment. The direction of the water flow can be controlled by the universal pipe head. The water pump 22 is a power pump that can control the water flow rate and water flow rate. The water flow rate can be controlled by the water pump 22, thereby simulating different water pressures. The water flow pressure can be monitored in real time by the flow sensor and the water pressure sensor, and the speed and flow rate of the water flow can be adjusted in time. The crack expansion of the tunnel lining can be observed for a long time by four observation cameras 24. The deformation of the tunnel lining monitored by the strain gauge 4 combined with the water flow pressure monitored by the flow sensor and the water pressure sensor can monitor the expansion of the lining cracks. The observation camera can monitor the length and width of the crack expansion, and the crack depth can be converted by the water flow pressure and the water flow rate, thereby analyzing the expansion of the lining cracks.

[0035] The electronic valve, lead screw 11, lead screw 2 12, hydraulic cylinder 1 6, hydraulic cylinder 2 7, electric hydraulic cylinder, water pump 22, telescopic element and the existing control system are electrically connected using the existing structure. The control system, strain gauge 4, observation camera 24, flow sensor, water pressure sensor and the existing monitoring system on the PC end are electrically connected using the existing structure.

[0036] Therefore, the present invention adopts the above-mentioned observation experimental device for tunnel lining crack expansion simulating a dynamic water environment, simulates the pressure load on the tunnel lining through a pressure simulation mechanism, simulates the water pressure in different directions and at different flow rates through a crack expansion observation mechanism, and monitors the expansion of tunnel lining cracks in real time, which plays an important role in the disease analysis and repair and maintenance of the tunnel lining.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An experimental device for observing crack expansion in tunnel lining simulating a dynamic water environment, characterized in that: The simulation test box includes a simulation test box, in which a test piece is arranged, the test piece includes a surrounding rock layer, a concrete lining test block with prefabricated cracks is arranged under the surrounding rock layer, a pressure simulation mechanism is arranged at the top and both sides of the simulation test box, a plurality of strain gauges are evenly arranged on the concrete lining test block, a lifting and translation assembly is arranged at the top of the simulation test box, the lifting and translation assembly is connected to the crack extension observation mechanism through a telescopic element, the crack extension observation mechanism includes a mounting plate, a water pump is arranged on the inner side of the mounting plate, an observation frame is connected to the outer side of the mounting plate, observation cameras are arranged on both sides of the observation frame, a plurality of water outlets are arranged in the middle of the observation frame, and the water pump is connected to the water outlets; The crack observation mechanism is arranged inside the simulation experiment box. One end of the water pump is connected to a water inlet pipe, on which a flow sensor is arranged. The other end of the water pump is connected to a water outlet through a water outlet pipe, on which a universal pipe head is arranged. The outlet of the universal pipe head is connected to a water pipe head with a flow sensor and a water pressure sensor. The observation camera and the water outlet are both arranged on the mounting plate. The lifting and translation assembly includes a double-screw translation structure, a waterproof box 1 is arranged below the double-screw translation structure, an electric hydraulic cylinder is arranged in the waterproof box 1, the hydraulic rod of the electric hydraulic cylinder is connected to the waterproof box 2, the telescopic element is an electric hydraulic cylinder, the telescopic element is arranged in the waterproof box 2, the hydraulic rod of the telescopic element is connected to the mounting plate, and the waterproof box 2 is connected to the mounting plate through a guide structure; The guide structure includes symmetrically arranged guide tubes, which are arranged on both sides of the second waterproof box. A guide rod is slidably arranged in the guide tube, one end of the guide rod is connected to the inner side of the mounting plate, and a limit block is arranged at the other end of the guide rod. The double screw translation structure includes screw 1 and screw 2. A moving block is sleeved on screw 1 and screw 2. The bottom end of the moving block is connected to waterproof box 1. One end of screw 1 is connected to the output shaft of motor 1. The other end of screw 1 is connected to the bearing. One end of screw 2 is connected to the output shaft of motor 2. The other end of screw 2 is connected to the bearing. A circular water tank is arranged at the top of the simulation experiment box, and the circular water tank is connected with the interior of the simulation experiment box through a pipeline, and an electronic valve is arranged on the pipeline; The pressure simulation mechanism includes a plurality of hydraulic cylinders 1 and a plurality of hydraulic cylinders 2. The hydraulic cylinders 1 are arranged in the middle of the circular water tank, and the hydraulic cylinders 2 are arranged on both sides of the simulation experiment box. The hydraulic rods of the hydraulic cylinders 1 and 2 are connected with pressure applying heads. The water in the circular water tank is groundwater with chemicals that simulate the real environment.

2. The observation experimental device for tunnel lining crack propagation simulating a dynamic water environment according to claim 1 is characterized by: The bottom layer of the simulation experiment box is provided with a tunnel foundation surface, which is connected to the surrounding rock layer and the bottom end of the concrete lining test block.

3. The observation experimental device for tunnel lining crack propagation simulating a dynamic water environment according to claim 1 is characterized by: The simulation experiment box is provided with a drain port, and the drain port is provided with a sealing cover.

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