Intelligent testing device and method for longitudinal freeze-thaw deformation characteristics of tunnel
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO UNIV
- Filing Date
- 2023-01-03
- Publication Date
- 2026-07-24
Smart Images
Figure CN116164992B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of tunnel engineering technology and relates to an intelligent testing device and method for longitudinal freeze-thaw deformation characteristics of tunnels, which is applicable to the testing of tunnel deformation characteristics. Background Technology
[0002] Tunnels are engineering structures buried underground and are one of the main forms of underground space. The lining structure plays both a load-bearing and protective role in tunnels, serving as the innermost layer of protection and a permanent structure crucial to the overall quality and safety of the tunnel. With the development of underground rail transit, tunnels are becoming increasingly common, but the freeze-thaw effect of the soil can cause irreversible damage. Common types of damage include cracking of the tunnel lining and settlement deformation of the arch. Existing testing equipment cannot simultaneously consider the impact of uneven freeze-thaw cycles along the tunnel's longitudinal direction on tunnel deformation, nor can it account for the adverse effects of changes in the diameter and circumferential position of the freezing pipe. Therefore, existing methods have the following shortcomings:
[0003] 1) Testing can only be conducted according to the procedure of first freezing heave and then thawing settlement, and the simultaneous effects of freezing heave and thawing settlement on the surrounding soil and tunnel cannot be considered.
[0004] 2) It can only be applied to working conditions where the tunnel has the same longitudinal dimension, and cannot be considered for tests where the lining thickness can vary along the longitudinal direction of the tunnel.
[0005] 3) The frost heave or thaw settlement effect around the freezing pipe is uniform, but in actual construction, longitudinally uneven frost heave and thaw settlement areas often appear around the freezing pipe. Summary of the Invention
[0006] To overcome the shortcomings of existing testing methods, such as difficulty in achieving longitudinal variations in lining thickness, longitudinal uneven freeze-thaw settlement, and adjustable dimensions and circumferential positions of heat and cold source pipes, this invention provides an intelligent testing device and method for longitudinal freeze-thaw deformation characteristics of tunnels. This method not only enables testing of tunnel deformation under longitudinal uneven freeze-thaw conditions, but is also simple, easy to operate, inexpensive, and has a short cycle time.
[0007] The technical solution adopted by this invention to solve its technical problem is:
[0008] An intelligent testing device for longitudinal freeze-thaw deformation characteristics of a tunnel includes a cold source, a heat source, a thermal insulation material position adjustment system, a thermal conductive material position adjustment system, a tunnel lining, a lining thickness adjustment system, front and rear panels, and a longitudinal zone partition plate. The thermal insulation material position adjustment system is located on the outermost ring of the testing device. The cold source and heat source are arranged circumferentially within the thermal insulation material position adjustment system. A water thermometer is located within the cold source and heat source. The thermal conductive material position adjustment system is located inside the thermal insulation material position adjustment system. The longitudinal zone partition plate is located at each boundary of the longitudinal zones. The tunnel lining is located at the circumferential center of the testing device. The lining thickness adjustment system is located inside the tunnel lining. The front and rear panels are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels and the thermal conductive material position adjustment system is filled with soil. An earth pressure cell, a displacement gauge, and a moisture content probe are installed within the soil area.
[0009] Furthermore, the insulation material position adjustment system includes insulation material, a cold / heat source pipe size adjustment knob, pipe walls, and circumferential slide rails. The pipe walls are located on two circumferential slide rails, one inside and one outside. The cavity formed by the pipe walls and the circumferential slide rails constitutes the cold source pipe and the heat source pipe. The cold / heat source pipe size adjustment knob is located at the point adjacent to each pipe wall and the circumferential slide rail. The insulation material is located at both ends of each cold and heat source. The heat-conducting material position adjustment system is located inside the insulation material position adjustment system. In this design, the circumferential positions of the cold and heat sources and the dimensions of the cold / heat source pipes are changed via the cold / heat source pipe size adjustment knob.
[0010] Furthermore, the thermally conductive material position adjustment system includes a thermally conductive material, a thermally conductive material position adjustment gear, serrations, and a thermally conductive material slide rail. The thermally conductive material slide rail is located inside the thermal insulation material position adjustment system. The thermally conductive material and the serrations are fixed to the thermally conductive material slide rail. The thermally conductive material position adjustment gear is located on the longitudinal region partition plate at the boundary of each longitudinal region. In this solution, the position of the thermally conductive material in the circumferential direction is changed by rotating the thermally conductive material position adjustment gear in each longitudinal region.
[0011] The tunnel lining includes an inner lining and an outer lining. The strain gauge is located on the contact surface between the tunnel lining and the soil. The lining thickness adjustment system is located inside the tunnel lining.
[0012] Furthermore, the lining thickness adjustment system includes a strut end and a telescopic strut, the strut end being located on the outer side of the inner lining and the inner side of the outer lining, and the telescopic strut connecting the two ends.
[0013] The front and rear panels include a cold source interface, a heat source interface, and a soil baffle. The cold source interface and the heat source interface are distributed in a ring on the front and rear panels, and their specific positions coincide with the positions of the cold source pipe and the heat source pipe. The soil baffle is located on the front and rear panels and coincides with the position of the soil.
[0014] The tunnel is divided into several areas along its longitudinal direction, and these areas are distinguished by longitudinal tunnel zone numbers.
[0015] The hot and cold sources are arranged in several zones along the ring direction and distinguished by hot and cold source zone numbers.
[0016] The thermally conductive material is arranged into several regions in the circumferential direction and distinguished by thermally conductive material numbers.
[0017] A smart testing method for the longitudinal freeze-thaw deformation characteristics of tunnels includes the following steps:
[0018] Step 1: Determine the dimensions and materials of the tunnel lining based on the project characteristics and testing requirements;
[0019] Step 2: Install an intelligent testing device for the longitudinal freeze-thaw deformation characteristics of the tunnel. The testing device includes a cold source, a heat source, a thermal insulation material position adjustment system, a thermal conductive material position adjustment system, a tunnel lining, a lining thickness adjustment system, front and rear panels, and a longitudinal zone partition plate. The thermal insulation material position adjustment system is located on the outermost ring of the testing device. The cold source and heat source are arranged circumferentially within the thermal insulation material position adjustment system. A water thermometer is located within the cold source and heat source. The thermal conductive material position adjustment system is located inside the thermal insulation material position adjustment system. The longitudinal zone partition plate is located at each boundary of the longitudinal zones. The tunnel lining is located at the circumferential center of the testing device. The lining thickness adjustment system is located inside the tunnel lining. The front and rear panels are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels and the thermal conductive material position adjustment system is filled with soil. An earth pressure cell, a displacement gauge, and a moisture content probe are installed within the soil area.
[0020] Step 3: Determine the temperature parameters of the cold source and heat source, turn on the external cold source and heat source switches, connect the cold source pipe and heat source pipe to the external cold source and heat source respectively, and reach the corresponding test temperature; set the cold source temperature and heat source temperature according to the test requirements; supply cold source to the installed cold source pipe through the cold source interface reserved on the front panel; supply heat source to the installed heat source pipe through the heat source interface reserved on the device box; the cold and heat sources flow back to the external cold and heat source system from the cold and heat source interfaces reserved on the rear panel and then flow into the cold and heat source pipes, forming an internal and external circulation of cold and heat sources;
[0021] Step 4: Start the experiment and collect data: Record the initial data of each sensor before the experiment begins. Once the temperature of the cold source and the heat source reaches the test temperature and remains constant, record the corresponding test data every half hour. Stop the experiment when the data at the test points stabilizes.
[0022] Step 5: Cyclic testing of different cold and heat source temperatures. Repeat steps 3 to 4. By changing the temperature of the external cold and heat sources, the frost heave and thaw settlement of soil at different cold and heat source temperatures can be tested simultaneously.
[0023] Furthermore, in step 2, the dimensions of the cold source pipe and the heat source pipe, and their circumferential positions on the insulation material positioning system, are determined according to engineering requirements; the circumferential position of the heat-conducting material is determined according to engineering requirements; and the different lining thicknesses of the tunnel are determined according to engineering requirements. The testing method also includes the following steps:
[0024] Step 6: Cyclic test of different thermal conductive material positions. Repeat steps 2 to 4. Adjust the circumferential position of the thermal conductive material by rotating the adjustment gears of the thermal conductive material positions in each longitudinal region. This can achieve testing of different thermal conductive material positions and different cold and heat source temperatures.
[0025] Step 7: Cyclic testing of different cold and heat source sizes and circumferential positions. Repeat steps 2 to 4. By changing the position of the cold and heat source pipe walls on the circumferential slide rails, tests can be performed on different cold and heat source pipe sizes and positions, different thermal conductive material positions, and different cold and heat source temperatures.
[0026] Step 8: Cyclic test of different tunnel lining thicknesses. Repeat steps 2 to 4. By controlling the length of the telescopic struts in each longitudinal region, the lining thickness of the tunnel in each longitudinal region can be adjusted. This allows for testing of different lining thicknesses, different sizes and positions of cold and heat source pipes, different positions of heat-conducting materials, and different cold and heat source temperatures.
[0027] Step 9: End the test, remove the soil, and dismantle the device.
[0028] The beneficial effects of this invention are mainly reflected in:
[0029] (1) It can test the simultaneous effects of soil frost heave and thaw settlement on tunnels;
[0030] (2) It can test the effects of frost heave and thaw settlement on the performance of tunnels with different longitudinal lining thicknesses;
[0031] (3) It can test the impact of longitudinal uneven frost heave and thaw settlement on tunnel performance;
[0032] (4) The size and circumferential position of the heat source pipe and the cold source pipe are adjustable;
[0033] (5) Easy to operate, low cost, and short cycle. Attached Figure Description
[0034] Figure 1 This is a front view of an intelligent testing device for the longitudinal freeze-thaw deformation characteristics of tunnels.
[0035] Figure 2 yes Figure 1 AA cross-section view.
[0036] Figure 3 This is a structural diagram of the thermal insulation material adjustment system.
[0037] Figure 4 This is a structural diagram of the thermal conductive material position adjustment system.
[0038] Figure 5 This is a structural diagram of the tunnel lining thickness adjustment system.
[0039] Figure 6 This is a structural diagram of the front and rear panels.
[0040] Among them, 1. Cold source; 2. Heat source; 3. Insulation material position adjustment system; 3-1. Insulation material; 3-2. Cold and heat source pipe size adjustment knob; 3-3. Pipe wall; 3-4. Pipe wall circumferential slide rail; 4. Heat-conducting material position adjustment system; 4-1. Heat-conducting material; 4-2. Heat-conducting material position adjustment gear; 4-3. Serrated edge; 4-4. Heat-conducting material slide rail; 5. Tunnel lining; 5-1. Inner lining; 5-2. Outer lining; 6. Lining Masonry thickness adjustment system; 6-1. Support rod end; 6-2. Telescopic support rod; 7. Strain gauge; 8. Water thermometer; 9. Moisture content probe; 10. Displacement gauge; 11. Earth pressure cell; 12. Soil; 13. Front and rear panels; 13-1. Cold source interface; 13-2. Heat source interface; 13-3. Soil layer baffle; 14. Longitudinal tunnel zoning number; 15. Cold and heat source zoning number; 16. Thermal conductive material number; 17. Longitudinal zone partition plate. Detailed Implementation
[0041] The present invention will now be further described with reference to the accompanying drawings.
[0042] Reference Figures 1-6An intelligent testing device for longitudinal freeze-thaw deformation characteristics of a tunnel includes a cold source 1, a heat source 2, a thermal insulation material position adjustment system 3, a thermal conductive material position adjustment system 4, a tunnel lining 5, a lining thickness adjustment system 6, front and rear panels 13, and a longitudinal zone partition plate 17. The thermal insulation material position adjustment system 3 is located on the outermost ring of the testing device. The cold source 1 and the heat source 2 are arranged circumferentially within the thermal insulation material position adjustment system 3. A water thermometer 8 is located within the cold source 12 and the heat source. The thermal conductive material position adjustment system 4 is located inside the thermal insulation material position adjustment system 3. The longitudinal zone partition plate 17 is located at each boundary of the longitudinal zones. The tunnel lining 5 is located at the circumferential center of the testing device. The lining thickness adjustment system 6 is located inside the tunnel lining 5. The front and rear panels 13 are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels 13 and the thermal conductive material position adjustment system 4 is filled with soil 12. A soil pressure cell 11, a displacement gauge 10, and a moisture content probe 9 are provided within the soil area.
[0043] Furthermore, the insulation material position adjustment system 3 includes insulation material 3-1, a cold / heat source pipe size adjustment knob 3-2, a pipe wall 3-3, and a pipe wall circumferential slide rail 3-4. The pipe wall is located on two inner and outer pipe wall circumferential slide rails. The cavity formed by the pipe wall and the pipe wall circumferential slide rails constitutes the cold source pipe and the heat source pipe. The cold / heat source pipe size adjustment knob is located at the point adjacent to each pipe wall and the pipe wall circumferential slide rail. The insulation material is located at the left and right ends of each cold and heat source. The heat-conducting material position adjustment system is located inside the insulation material position adjustment system. In this scheme, the circumferential position of the cold and heat sources and the size of the cold / heat source pipes are changed through the cold / heat source pipe size adjustment knob.
[0044] Furthermore, the thermally conductive material position adjustment system 4 includes a thermally conductive material 4-1, a thermally conductive material position adjustment gear 4-2, a sawtooth 4-3, and a thermally conductive material slide rail 4-4. The thermally conductive material slide rail is located inside the thermal insulation material position adjustment system. The thermally conductive material and the sawtooth are fixed on the thermally conductive material slide rail. The thermally conductive material position adjustment gear is located on the longitudinal region partition plate at the boundary of each longitudinal region. In this scheme, the position of the thermally conductive material in the circumferential direction is changed by rotating the thermally conductive material position adjustment gear in each longitudinal region.
[0045] The tunnel lining 5 includes an inner lining 5-1 and an outer lining 5-2. The strain gauge is located on the contact surface between the tunnel lining and the soil, and the lining thickness adjustment system is located inside the tunnel lining.
[0046] Furthermore, the lining thickness adjustment system 6 includes a strut end 6-1 and a telescopic strut 6-2. The strut end is located on the outer side of the inner lining and the inner side of the outer lining, and the telescopic strut connects the two ends.
[0047] The front and rear panels 13 include a cold source interface 13-1, a heat source interface 13-2, and a soil baffle 13-3. The cold source interface and the heat source interface are distributed in a ring on the front and rear panels, and their specific positions coincide with the positions of the cold source pipe and the heat source pipe. The soil baffle is located on the front and rear panels and coincides with the position of the soil.
[0048] The tunnel is divided into several areas along its longitudinal direction, and these areas are distinguished by longitudinal tunnel section number 14.
[0049] The hot and cold sources are arranged in several zones along the ring direction, and are distinguished by the hot and cold source zone number 15.
[0050] The thermally conductive material is arranged into several regions in the circumferential direction and distinguished by the thermally conductive material number 16.
[0051] A smart testing method for the longitudinal freeze-thaw deformation characteristics of tunnels includes the following steps:
[0052] Step 1: Determine the dimensions and materials of the tunnel lining based on the project characteristics and testing requirements;
[0053] Step 2: Install an intelligent testing device for the longitudinal freeze-thaw deformation characteristics of the tunnel. The testing device includes a cold source 1, a heat source 2, a thermal insulation material position adjustment system 3, a thermal conductive material position adjustment system 4, a tunnel lining 5, a lining thickness adjustment system 6, front and rear panels 13, and a longitudinal zone partition plate 17. The thermal insulation material position adjustment system 3 is located on the outermost ring of the testing device. The cold source 1 and the heat source 2 are arranged circumferentially within the thermal insulation material position adjustment system 3. A water thermometer 8 is located in the cold source 12 and the heat source. The thermal conductive material position adjustment system 4 is located inside the thermal insulation material position adjustment system 3. The longitudinal zone partition plate 17 is located at each boundary of the longitudinal zones. The tunnel lining 5 is located at the circumferential center of the testing device. The lining thickness adjustment system 6 is located inside the tunnel lining 5. The front and rear panels 13 are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels 13 and the thermal conductive material position adjustment system 4 is filled with soil 12. A soil pressure cell 11, a displacement gauge 10, and a moisture content probe 9 are installed in the soil area.
[0054] Step 3: Determine the temperature parameters of the cold source and heat source, turn on the external cold source and heat source switches, connect the cold source pipe and heat source pipe to the external cold source and heat source respectively, and reach the corresponding test temperature; set the cold source temperature and heat source temperature according to the test requirements; supply cold source to the installed cold source pipe through the cold source interface reserved on the front panel; supply heat source to the installed heat source pipe through the heat source interface reserved on the device box; the cold and heat sources flow back to the external cold and heat source system from the cold and heat source interfaces reserved on the rear panel and then flow into the cold and heat source pipes, forming an internal and external circulation of cold and heat sources;
[0055] Step 4: Start the experiment and collect data: Record the initial data of each sensor before the experiment begins. Once the temperature of the cold source and the heat source reaches the test temperature and remains constant, record the corresponding test data every half hour. Stop the experiment when the data at the test points stabilizes.
[0056] Step 5: Cyclic testing of different cold and heat source temperatures. Repeat steps 3 to 4. By changing the temperature of the external cold and heat sources, the frost heave and thaw settlement of soil at different cold and heat source temperatures can be tested simultaneously.
[0057] A city's underground tunnel has an inner diameter of 6.3m and a burial depth of 15m. The tunnel excavation requires the freezing method. To test the simultaneous effects of frost heave and thaw settlement, as well as the impact of uneven freeze-thaw effects caused by changes in longitudinal lining thickness, the intelligent testing device and operating method for longitudinal freeze-thaw deformation characteristics of tunnels provided by this invention are used to test the influence of longitudinal uneven freeze-thaw effects on the deformation characteristics of tunnel linings of different thicknesses.
[0058] In this embodiment, the testing device is a cylinder with a length of 10.5m, an inner diameter of 6.3m, and an outer diameter of 12.3m. The cold source and the heat source are connected to the cold source pipe and the heat source pipe of the device from the front, forming a circulation system for the cold source and the heat source, respectively.
[0059] The implementation scheme of the present invention is as follows:
[0060] 1) Determine the dimensions and material of the tunnel lining. Based on the engineering characteristics and testing requirements, C60 reinforced concrete was used for this test tunnel. The inner diameter of the tunnel lining is 6.3m, and the entire tunnel is divided into 7 zones along the longitudinal direction, numbered ① to ⑦.
[0061] 2) Assemble the lining thickness adjustment system. Along the longitudinal direction, from area ① to ⑦, the ends 6-1 of the support rods are fixed at equal intervals circumferentially on the outer side of the inner lining 5-1 and the inner side of the outer lining 5-2. Then, the two ends are connected using telescopic support rods 6-2. The lining thickness for each area is determined according to project requirements and is adjusted by controlling the length of the telescopic support rods of the tunnel lining thickness adjustment system, as shown in Table 1.
[0062] Table 1 shows the thickness of tunnel lining.
[0063] serial number ① ② ③ ④ ⑤ ⑥ ⑦ Thickness (cm) 40 70 100 30 65 55 90
[0064] Table 1
[0065] 3) Arrange tunnel strain gauges 7 and splice the tunnel. Install 20 sets of strain gauges at equal intervals on the contact surface between the tunnel lining and the soil in each ring. Adjacent tunnel lining rings in areas ① to ⑦ are assembled using bolts.
[0066] 4) Assemble the cold source pipes. Based on the project characteristics and testing requirements, there are 6 cold source pipes, numbered 1, 3, 5, 7, 9, and 11. First, loosen the cold and hot source pipe size adjustment knobs 3-2 on both sides of pipe wall 3-3. According to the width of each cold source pipe, move pipe wall 3-8 to the corresponding position on the circumferential slide rail 3-4. Then, tighten the cold and hot source pipe size adjustment knobs 3-2 to fix the position of the cold source pipes. The cold source pipes are made of steel, with a fan-shaped cross-section. The large fan radius is 6m, and the small fan radius is 5m. The heat-conducting material inside each cold source pipe is determined according to project requirements, with a thickness of 90mm. The central angle of the cold source pipe is also determined according to project requirements, as detailed in Table 2.
[0067] Table 2 shows the center angle of the cold source pipe.
[0068] serial number 1 3 5 7 9 11 Central angle (°) 21 29 21 21 34 21
[0069] Table 2
[0070] 5) Assemble the heat source pipes. Based on the project characteristics and testing requirements, the heat source pipes are divided into 6 zones, numbered 2, 4, 6, 8, 10, and 12. First, loosen the hot and cold source pipe size adjustment knobs 3-2 on both sides of the pipe wall 3-3. According to the width of each heat source pipe, move the pipe wall 3-3 to the corresponding position on the circumferential slide rail 3-4. Then, tighten the hot and cold source pipe size adjustment knobs 3-2 to fix the position of the heat source pipes. The heat source pipes are made of steel, with a fan-shaped cross-section. The large fan radius is 6m, and the small fan radius is 5m. The heat-conducting material inside each heat source pipe is determined according to project requirements, with a thickness of 90mm. The central angle of the heat source pipe is also determined according to project requirements; see Table 3 for details.
[0071] Table 3 shows the center angle of the heat source pipe.
[0072] serial number 2 4 6 8 10 12 Central angle (°) 31 21 57 39 26 39
[0073] Table 3
[0074] 6) Install cold and heat source pipes to form different combinations. To test the simultaneous effect of longitudinal unevenness of the soil on the lining and soil of the tunnel's longitudinal thickness variation, arrange the cold and heat source pipes assembled in step 4 and step 5 in a ring according to their serial numbers from smallest to largest, forming a cross-arrangement type of cold and heat source pipes. The positions of the cold and heat source pipes can also be adjusted according to project needs to form different combinations of cold and heat source pipes. Apply insulation material 3-1 to the left and right ends of the cold and heat source pipes. To achieve the required insulation, glass wool with a thickness of 40mm is selected as insulation material 3-1.
[0075] 7) Install slide rails 4-4 and thermally conductive material 4-1. Install longitudinal zone dividers 17 at each boundary of zones ① to ⑦. Fix the thermally conductive material slide rails 4-4 of each zone ① to ⑦ to the inside of the hot and cold source pipes. Install the 7 sawtooth teeth 4-3 on the thermally conductive material slide rails 4-4 at positions close to the longitudinal zone dividers 17. Fix the thermally conductive material 4-1 with the corresponding thermal conductivity in Table 4 on the corresponding positions of the thermally conductive material slide rails 4-4 in the hot and cold source pipe zones. Install the thermally conductive material position adjustment gear 4-2 on the longitudinal zone dividers 17 at the zone boundaries, so that the gear 4-2 in each zone meshes with the sawtooth teeth 4-3. The circumferential position of the thermally conductive material in each zone ① to ⑦ can be adjusted by rotating the thermally conductive material position adjustment gear 4-2.
[0076] Table 4 shows the thermal conductivity of thermally conductive materials.
[0077] Thermal conductive material area number Guide-1 Guide-2 Guide-3 Guide-4 5-1 6-1 Thermal conductivity (W / mK) 1 2 3 4 5 6 Thermal conductive material area number Pathfinder-7 Dao-8 9-1 Dao-10 Dao-11 Dao-12 Thermal conductivity (W / mK) 7 8 9 10 11 12
[0078] 8) Install the cold and heat source circulation system. Connect the external cold source to the cold source pipe through cold source interface 13-1, and connect the external heat source to the heat source pipe through heat source interface 13-2. The cold and heat source interfaces can be adjusted according to the needs of the project.
[0079] 9) Install sensors in the soil layer. Based on the thickness of the soil layer and the required locations of the test parameters, install the corresponding sensors in the soil layer. The sensor installation is synchronized with the soil layer filling. When the soil layer filling height reaches the tunnel bottom elevation, install the tunnel lining. The soil layer baffle 13-3 consists of 7 plates. When the internal soil layer filling height reaches the top of the corresponding baffle, install the next baffle until the internal soil layer filling is complete. The specific locations of the sensors are as follows: the moisture content probe 9, displacement gauge 10, and earth pressure cell 11 are evenly arranged circumferentially, with eight sensors evenly spaced in each area. Seven sets of sensors are evenly spaced in each area along the longitudinal direction ①-⑦.
[0080] 10) Determine the temperature parameters of cold source 1 and heat source 2. Turn on the external cold source and heat source switches, connect the cold source pipe and heat source pipe to the external cold source and heat source respectively, and reach the corresponding test temperatures. According to the test requirements, the cold source temperature is -40℃ and the heat source temperature is 30℃. Cold source 1 is supplied to the installed cold source pipe through the cold source interface 13-1 reserved on the front panel. According to the test requirements, sodium chloride solution is used for cold source 1. Heat source 2 is supplied to the installed heat source pipe through the heat source interface 13-2 reserved on the front panel. According to the test requirements, pure water is used for heat source 2. The cold and heat sources flow back to the external cold and heat source systems from the cold and heat source interfaces reserved on the rear panel, and then flow back into the cold and heat source pipes, forming an internal and external circulation of the cold and heat sources.
[0081] 11) Start the experiment and collect data. Record the initial data of each sensor before the experiment begins. After the cold source and heat source temperatures reach the test temperature in step 10) and remain constant, record the test data of the corresponding sensor every half hour. Stop the experiment when the sensor data stabilizes.
[0082] 12) Cyclic testing with different cold and heat source temperatures: Repeat steps 10) to 11). By changing the temperature of the external cold and heat source, the soil frost heave and thaw settlement under different cold and heat source temperature conditions can be tested simultaneously.
[0083] 13) Cyclic test of different thermal conductive material positions: Repeat steps 7) to 11). Adjust the circumferential position of 12 thermal conductive materials in 7 regions by rotating the thermal conductive material position adjustment gear 4-2 in each of the 7 regions. This allows the 7 longitudinal regions of the tunnel to be set with thermal conductive materials corresponding to the engineering requirements, enabling the testing of different thermal conductive material positions and different cold and heat source temperatures.
[0084] 14) Cyclic testing with different sizes and positions of cold and heat source pipes. Repeat steps 4) to 11). By changing the position of the pipe wall 3-8 of the cold and heat source pipes on the circumferential slide rail 3-4, it is possible to test the working conditions of different sizes and positions of cold and heat source pipes, different positions of heat-conducting materials, and different cold and heat source temperatures.
[0085] 15) Cyclic test of different tunnel lining thicknesses: Repeat steps 2) to 11). By controlling the length of the telescopic struts 6-2 in 7 areas, the lining thickness of each longitudinal area of the tunnel can be adjusted. This can achieve working condition testing with different lining thicknesses, different sizes and positions of cold and heat source pipes, different positions of heat-conducting materials, and different cold and heat source temperatures.
[0086] 16) End the test, remove the soil, and dismantle the equipment. Turn off the test instrument, clear the soil 12, and dismantle the hot and cold source pipes, the heat conduction material position adjustment system, and the insulation material position adjustment system to complete the test.
[0087] The embodiments described in this specification are merely examples of implementations of the inventive concept and are for illustrative purposes only. The scope of protection of this invention should not be considered limited to the specific forms described in these embodiments; rather, it extends to equivalent technical means conceived by those skilled in the art based on the inventive concept.
Claims
1. An intelligent testing device for the longitudinal freeze-thaw deformation characteristics of tunnels, characterized in that, The device includes a cold source, a heat source, a thermal insulation material position adjustment system, a thermal conductive material position adjustment system, a tunnel lining, a lining thickness adjustment system, front and rear panels, and a longitudinal zone partition plate. The thermal insulation material position adjustment system is located on the outermost ring of the testing device. The cold source and heat source are arranged circumferentially within the thermal insulation material position adjustment system. A water thermometer is located within the cold source and heat source. The thermal conductive material position adjustment system is located inside the thermal insulation material position adjustment system. The longitudinal zone partition plate is located at each boundary of the longitudinal zones. The tunnel lining is located at the circumferential center of the testing device. The lining thickness adjustment system is located inside the tunnel lining. The front and rear panels are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels and the thermal conductive material position adjustment system is filled with soil. An earth pressure cell, a displacement gauge, and a moisture content probe are installed within the soil area. The insulation material position adjustment system includes insulation material, cold and hot source pipe size adjustment knobs, pipe walls, and pipe wall circumferential slide rails. The pipe walls are located on two inner and outer pipe wall circumferential slide rails. The cavity formed by the pipe walls and the pipe wall circumferential slide rails is the cold source pipe and the hot source pipe. The cold and hot source pipe size adjustment knobs are located at the junction of each pipe wall and the pipe wall circumferential slide rail. The insulation material is located at the left and right ends of each cold source and hot source. The heat conduction material position adjustment system is located inside the insulation material position adjustment system. The thermal conductive material position adjustment system includes thermal conductive material, thermal conductive material position adjustment gear, saw teeth, and thermal conductive material slide rail. The thermal conductive material slide rail is located inside the thermal insulation material position adjustment system. The thermal conductive material and the saw teeth are fixed on the thermal conductive material slide rail. The thermal conductive material position adjustment gear is located on the longitudinal region partition plate at the boundary of each longitudinal region. The tunnel lining includes an inner lining and an outer lining. Strain gauges are located on the contact surface between the tunnel lining and the soil. The lining thickness adjustment system is located inside the tunnel lining. The lining thickness adjustment system includes a strut end and a telescopic strut. The strut end is located on the outer side of the inner lining and the inner side of the outer lining, and the telescopic strut connects the two ends.
2. The intelligent testing device for longitudinal freeze-thaw deformation characteristics of tunnels as described in claim 1, characterized in that, The front and rear panels include a cold source interface, a heat source interface, and a soil baffle. The cold source interface and the heat source interface are distributed in a ring on the front and rear panels, and their specific positions coincide with the positions of the cold source pipe and the heat source pipe. The soil baffle is located on the front and rear panels and coincides with the position of the soil.
3. The intelligent testing device for longitudinal freeze-thaw deformation characteristics of tunnels as described in claim 1, characterized in that, The tunnel is divided into several areas along its longitudinal direction, and these areas are distinguished by longitudinal tunnel zone numbers.
4. The intelligent testing device for longitudinal freeze-thaw deformation characteristics of tunnels as described in claim 1, characterized in that, The hot and cold sources are arranged in several zones along the ring direction and distinguished by hot and cold source zone numbers; The thermally conductive material is arranged into several regions in the circumferential direction and distinguished by thermally conductive material numbers.
5. A method for implementing the intelligent testing device for longitudinal freeze-thaw deformation characteristics of tunnels as described in claim 1, characterized in that, The method includes the following steps: Step 1: Determine the dimensions and materials of the tunnel lining based on the project characteristics and testing requirements; Step 2: Install an intelligent testing device for the longitudinal freeze-thaw deformation characteristics of the tunnel. The testing device includes a cold source, a heat source, a thermal insulation material position adjustment system, a thermal conductive material position adjustment system, a tunnel lining, a lining thickness adjustment system, front and rear panels, and a longitudinal zone partition plate. The thermal insulation material position adjustment system is located on the outermost ring of the testing device. The cold source and heat source are arranged circumferentially within the thermal insulation material position adjustment system. A water thermometer is located within the cold source and heat source. The thermal conductive material position adjustment system is located inside the thermal insulation material position adjustment system. The longitudinal zone partition plate is located at each boundary of the longitudinal zones. The tunnel lining is located at the circumferential center of the testing device. The lining thickness adjustment system is located inside the tunnel lining. The front and rear panels are located at the front and rear ends of the entire testing device, respectively. The cavity formed by the front and rear panels and the thermal conductive material position adjustment system is filled with soil. An earth pressure cell, a displacement gauge, and a moisture content probe are installed within the soil area. Step 3: Determine the temperature parameters of the cold source and heat source, turn on the external cold source and heat source switches, connect the cold source pipe and heat source pipe to the external cold source and heat source respectively, and reach the corresponding test temperature; set the cold source temperature and heat source temperature according to the test requirements; supply cold source to the installed cold source pipe through the cold source interface reserved on the front panel; supply heat source to the installed heat source pipe through the heat source interface reserved on the device box; the cold and heat sources flow back to the external cold and heat source system from the cold and heat source interfaces reserved on the rear panel and then flow into the cold and heat source pipes, forming an internal and external circulation of cold and heat sources; Step 4: Start the experiment and collect data: Record the initial data of each sensor before the experiment begins. Once the temperature of the cold source and the heat source reaches the test temperature and remains constant, record the corresponding test data every half hour. Stop the experiment when the data at the test points stabilizes. Step 5: Cyclic testing of different cold and heat source temperatures. Repeat steps 3 to 4. By changing the temperature of the external cold and heat sources, the frost heave and thaw settlement of soil at different cold and heat source temperatures can be tested simultaneously.
6. The method as described in claim 5, characterized in that, In step 2, the dimensions of the cold source pipe and the heat source pipe, and their circumferential positions on the insulation material positioning system are determined according to engineering requirements; the circumferential position of the heat-conducting material is determined according to engineering requirements; and the different lining thicknesses of the tunnel are determined according to engineering requirements. The testing method also includes the following steps: Step 6: Cyclic test of different thermal conductive material positions. Repeat steps 2 to 4. Adjust the circumferential position of the thermal conductive material by rotating the adjustment gears of the thermal conductive material positions in each longitudinal region. This can achieve testing of different thermal conductive material positions and different cold and heat source temperatures. Step 7: Cyclic testing of different cold and heat source sizes and circumferential positions. Repeat steps 2 to 4. By changing the position of the cold and heat source pipe walls on the circumferential slide rails, tests can be performed on different cold and heat source pipe sizes and positions, different thermal conductive material positions, and different cold and heat source temperatures. Step 8: Cyclic test of different tunnel lining thicknesses. Repeat steps 2 to 4. By controlling the length of the telescopic struts in each longitudinal region, the lining thickness of the tunnel in each longitudinal region can be adjusted. This allows for testing of different lining thicknesses, different sizes and positions of cold and heat source pipes, different positions of heat-conducting materials, and different cold and heat source temperatures. Step 9: End the test, remove the soil, and dismantle the device.