Fabricated lining device and method with visual internal force

Abstract

The invention belongs to the technical field of tunnel engineering monitoring, and particularly relates to an internal force visualization fabricated lining device and method, internal force visualization is based on a thin film pressure sensing technology, and a thin film pressure sensor is composed of a thin film polyester material, a piezoelectric material, a signal transmission silver wire and a signal connection assembly. The piezoelectric material layer is wrapped by two layers of polyester insulating surfaces, two groups of strip-shaped piezoelectric materials are arranged in a criss-cross manner to form a complete grid shape, and each grid node is a pressure measuring unit. The sensor is long in fatigue life, high in deformability, high in response speed and sensitive in signal capture, real-time monitoring of the whole construction process can be achieved, and possibility is provided for visualization of lining internal force. The construction operation risk is effectively prevented, the tunnel lining damage hidden danger is reduced, and the method can be suitable for tunnel engineering under various complex geological conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel engineering monitoring, and in particular, relates to an assembled lining device and method for visualizing internal forces. Background Art

[0002] As an infrastructure that crosses different terrains, tunnel engineering plays a vital role in the field of modern transportation. It overcomes natural obstacles through underground excavation and channel construction, improving traffic convenience and transportation safety. Prefabricated segments are commonly used as support structures in tunnel engineering. They are cast and prefabricated in factories and assembled into rings to form tunnel linings, which play a role in supporting and protecting tunnels. They are especially widely used in shield construction. In order to ensure the service quality and performance of prefabricated segments, monitoring is essential. However, there are still some problems with monitoring, which may affect the overall quality and safety of tunnel engineering. The detection means are limited, and the traditional methods are highly dependent. The measurement and judgment with the help of manual visual inspection and measuring tools are inefficient and have large errors. Point sensors are installed on the segments to regularly measure changes in pressure, displacement, temperature, etc. to evaluate their long-term service stability. However, the disadvantage is that the distribution of monitoring points is limited, it is difficult to evaluate the overall status of the segments, and the data collection frequency is low, requiring manual regular reading, and real-time monitoring is impossible.

[0003] In tunnel engineering, distributed fiber optic sensors have been widely studied and applied due to their high sensitivity, long-distance monitoring capability and anti-electromagnetic interference. The sensor uses optical fiber as a sensing element to achieve continuous distributed measurement of environmental parameters along the fiber path. Based on the optical time domain reflectometer (OTDR) technology, the physical changes along the length of the fiber are detected by measuring the scattering and reflection of light in the fiber. It is often used to monitor the deformation of the lining, temperature distribution, dynamic response and traffic flow in the tunnel, and eliminate safety hazards in time to ensure the safe operation of the tunnel. Although distributed fiber optic sensors have shown outstanding advantages in the field of tunnels, they still face some disadvantages and challenges: 1. The cost is high, including the cost of detection, installation, post-maintenance and calibration; 2. It is very difficult to install distributed fiber optic sensors in some complex or narrow spaces; 3. In long-distance monitoring, the sensor wiring is complex, and the data generated requires efficient processing and analysis methods; 4. The internal optical path and grating structure of the fiber optic sensor are sensitive to temperature changes, and real-time calibration and temperature compensation are required, which increases the difficulty and cost of use.

[0004] As a new type of high-precision and high-sensitivity thin film pressure sensor, when subjected to external pressure, the surface film will undergo slight deformation, which will cause the resistance value on the film to change. By monitoring the change in resistance, the magnitude of the applied pressure can be determined. With its advantages such as economy and convenience, it has become the first choice for tunnel detection, road construction, and healthy operation and maintenance. With the help of the information data collection of the sensing system, the internal force change trend of the monitoring structure is output in real time, achieving long-term and efficient visual monitoring, and ensuring the safety and durability of civil engineering.

[0005] Therefore, the present invention is an assembled lining device and method with visualized internal forces, and provides a segment monitoring method based on a thin film pressure sensor, aiming to realize the health monitoring of the new prefabricated segments throughout their life cycle, and provide a certain reference for the field of tunnel engineering. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an assembled lining device and method with visualized internal forces, thereby solving the problems raised in the above-mentioned background technology.

[0007] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] A method for visualizing internal forces of assembled linings, comprising the following steps:

[0009] S1. Assemble corresponding prefabricated segment molds according to different tunnel cross-sectional shapes; wherein the prefabricated segment molds are made of mold steel and consist of a bottom plate, four side plates and two upper covers, which can meet the requirements of tunnels with different diameters and cross-sectional shapes;

[0010] S2. Make a steel skeleton according to the design specifications to ensure that the steel bars are correctly connected to the mold; use a bracket or a fixture to fix the steel skeleton in the mold to prevent displacement during the pouring process;

[0011] S3. Select a thin film pressure sensor with a suitable working range and temperature range, and cover it on the surface of the steel skeleton to monitor the pressure changes inside the prefabricated pipe segment in real time; wherein, the main structure of the thin film pressure sensor is a layer of semiconductor piezoelectric material wrapped in two layers of polyester insulating outer surface, with an overall thickness of only 0.2mm, a working range of 10000N, and a maximum working temperature of 100°C. The two groups of vertically intersecting strips of piezoelectric material in the piezoelectric material layer form a complete grid, and each grid node is a pressure measuring unit, and the size of each unit is 20mm×20mm. The horizontal and vertical layout dimensions can be customized according to the size and spacing of the steel bars, and the surface of the steel bars can be covered; in order to avoid unreliable bonding between the outer surfaces of the polyester insulation under long-term monitoring conditions, the sensor is packaged, that is, epoxy resin is used as an adhesive; on the inner wall of the polyester material, a silver wire for transmitting signals is sprayed to connect the piezoelectric material layer to the signal connection component, and the signal connection component transmits, reads and processes signals by connecting to an external circuit;

[0012] S4. Pour the concrete according to the designed mix ratio and vibrate during the pouring process to remove the residual air inside;

[0013] S5. After pouring, steam curing is used to accelerate the hardening of concrete, and the temperature and humidity are controlled to ensure the steady development of concrete strength; wherein, the steam curing utilizes the heat and humidity provided by steam to accelerate the cement hydration reaction in concrete, and includes four stages: preheating stage, heating stage, constant temperature stage and cooling stage;

[0014] S6. Remove the mold, perform demoulding, trimming, and place in a water pool for curing; during the demoulding and demoulding process, damage to the surface of the segment should be reduced, and soft rubber pads should be used to protect the segment when necessary. Demolding should be carried out from top to bottom and from outside to inside to ensure a smooth and orderly demoulding process.

[0015] An assembled lining device with visualized internal force comprises a prefabricated pipe segment and a steel skeleton, a thin film pressure sensor is arranged on the steel skeleton, the thin film pressure sensor comprises an upper surface of polyester material and a lower surface of polyester material, signal transmission silver wires and piezoelectric material layers are arranged on the opposite surfaces of the upper surface of polyester material and the lower surface of polyester material, a signal connection component matching with the signal transmission silver wire is arranged at one end of the opposite surface of the upper surface of polyester material and the lower surface of polyester material, a pressure measuring unit is arranged on the signal transmission silver wire and the piezoelectric material layer, and a pin is arranged at one end of the thin film pressure sensor.

[0016] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0017] 1. The thin film pressure sensor is a flexible sensor with strong adaptability to meet various working conditions.

[0018] 2. The thin film pressure sensor has the characteristics of high precision, fast response, small size, easy installation and strong durability, which can realize the efficient and accurate monitoring of the internal force of the precast concrete segment structure.

[0019] 3. The thin film pressure sensor can more intuitively reflect the overall stress condition of the structure, realize the visualization of internal data, and provide technical support for structural health monitoring.

[0020] 4. Compared with traditional sensors, the outer surface of the thin film of the thin film pressure sensor is made of polymer material, which has excellent flexibility and plasticity. This feature can adapt to various irregular shapes and even curved surfaces, and can be widely used in different complex working conditions.

[0021] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] In the figure:

[0024] Figure 1 It is a construction process flow chart of the present invention;

[0025] Figure 2 This is a disassembled stereoscopic diagram of the thin film pressure sensor of the present invention;

[0026] Figure 3 It is a front view of the thin film pressure sensor package of the present invention;

[0027] Figure 4 A side view of the thin film pressure sensor package of the present invention;

[0028] Figure 5 This is an overall effect diagram of the prefabricated pipe segment of the present invention.

[0029] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0030] 1. Upper surface of polyester material; 2. Lower surface of polyester material; 3. Piezoelectric material layer; 4. Signal transmission silver wire; 5. Pressure measuring unit; 6. Signal connection component; 7. Prefabricated pipe segment; 8. Steel bar skeleton; 9. Thin film pressure sensor; 10. Pins.

[0031] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0032] The present invention will now be described in further detail with reference to the accompanying drawings.

[0033] Example 1: Please refer to Figure 1-5 As shown, in this embodiment, a method for visualizing internal forces of an assembled lining is provided, comprising the following steps:

[0034] S1. Assemble corresponding prefabricated segment molds according to different tunnel cross-sectional shapes; wherein the prefabricated segment molds are made of mold steel and consist of a bottom plate, four side plates and two upper covers, which can meet the requirements of tunnels with different diameters and cross-sectional shapes;

[0035] S2. Make a steel skeleton according to the design specifications to ensure that the steel bars are correctly connected to the mold; use a bracket or a fixture to fix the steel skeleton in the mold to prevent displacement during the pouring process;

[0036] S3. Select a thin film pressure sensor with a suitable working range and temperature range, and cover it on the surface of the steel skeleton to monitor the pressure changes inside the prefabricated pipe segment in real time; wherein, the main structure of the thin film pressure sensor is a layer of semiconductor piezoelectric material wrapped in two layers of polyester insulating outer surface, with an overall thickness of only 0.2mm, a working range of 10000N, and a maximum working temperature of 100°C. The two groups of vertically intersecting strips of piezoelectric material in the piezoelectric material layer form a complete grid, and each grid node is a pressure measuring unit, and the size of each unit is 20mm×20mm. The horizontal and vertical layout dimensions can be customized according to the size and spacing of the steel bars, and the surface of the steel bars can be covered; in order to avoid unreliable bonding between the outer surfaces of the polyester insulation under long-term monitoring conditions, the sensor is packaged, that is, epoxy resin is used as an adhesive; on the inner wall of the polyester material, a silver wire for transmitting signals is sprayed to connect the piezoelectric material layer to the signal connection component, and the signal connection component transmits, reads and processes signals by connecting to an external circuit;

[0037] S4. Pour the concrete according to the designed mix ratio and vibrate during the pouring process to remove the residual air inside;

[0038] S5. After pouring, steam curing is used to accelerate the hardening of concrete, and the temperature and humidity are controlled to ensure the steady development of concrete strength; wherein, the steam curing utilizes the heat and humidity provided by steam to accelerate the cement hydration reaction in concrete, and includes four stages: preheating stage, heating stage, constant temperature stage and cooling stage;

[0039] S6. Remove the mold, perform demoulding, trimming, and place in a water pool for curing; during the demoulding and demoulding process, damage to the surface of the segment should be reduced, and soft rubber pads should be used to protect the segment when necessary. Demolding should be carried out from top to bottom and from outside to inside to ensure a smooth and orderly demoulding process.

[0040] Embodiment 2: An assembled lining device with visualized internal force comprises a prefabricated pipe segment 7 and a steel skeleton 8, a thin film pressure sensor 9 is arranged on the steel skeleton 8, the thin film pressure sensor 9 comprises a polyester material upper surface 1 and a polyester material lower surface 2, signal transmission silver wire 4 and piezoelectric material layer 3 are arranged on the opposite surfaces of the polyester material upper surface 1 and the polyester material lower surface 2, a signal connection component 6 matching with the signal transmission silver wire 4 is arranged on one end of the opposite surfaces of the polyester material upper surface 1 and the polyester material lower surface 2, a pressure measuring unit 5 is arranged on the signal transmission silver wire 4 and the piezoelectric material layer 3, and a pin 10 is arranged at one end of the thin film pressure sensor 9.

[0041] 1. The thin film pressure sensor is a flexible sensor with strong adaptability to meet various working conditions.

[0042] 2. The thin film pressure sensor has the characteristics of high precision, fast response, small size, easy installation and strong durability, which can realize the efficient and accurate monitoring of the internal force of the precast concrete segment structure.

[0043] 3. The thin film pressure sensor can more intuitively reflect the overall stress condition of the structure, realize the visualization of internal data, and provide technical support for structural health monitoring.

[0044] 4. Compared with traditional sensors, the outer surface of the thin film of the thin film pressure sensor is made of polymer material, which has excellent flexibility and plasticity. This feature can adapt to various irregular shapes and even curved surfaces, and can be widely used in different complex working conditions.

[0045] Example 3: Figures 1 to 4 As shown, the present invention provides a method for visualizing internal forces of assembled lining, comprising the following steps:

[0046] S1. Assemble the corresponding prefabricated segment molds according to the different cross-sectional shapes of the tunnel;

[0047] Refer to the tunnel cross-section shape and design dimensions to select the appropriate segment mold.

[0048] Rinse the mold before use to remove any impurities on the surface. Apply a release agent evenly on the inner surface to ensure a smooth surface and easy demoulding. Strictly follow the assembly process to avoid deformation of the mold.

[0049] S2. Make the steel skeleton according to the design specifications to ensure the correct connection between the steel bars and the mold;

[0050] The steel bar layout meets the requirements of the specification and is connected by welding. Plastic brackets are used to fix the steel bar skeleton in the mold to prevent displacement during the pouring process.

[0051] Regularly inspect and debug equipment such as steel bar cutting machines and bending machines to ensure that steel bar processing meets the requirements of segment production.

[0052] S3. Select a thin film pressure sensor with a suitable working range and temperature range, and cover it on the surface of the steel skeleton to monitor the pressure changes inside the prefabricated pipe segment in real time;

[0053] The selected thin film pressure sensor has a thickness of 0.2mm, a working range of 10000N, and a maximum working temperature of 100°C. The size of each pressure measuring unit is 20mm×20mm. The horizontal and vertical layout dimensions can be customized according to the size and spacing of the steel bars, and the surface of the steel bars can be covered.

[0054] Further optimization scheme, when the inductive piezoresistive ink coating is subjected to pressure, its geometric shape changes. The change of pressure value at any pressure measuring unit will cause the change of resistance value at that point, and then cause the change of corresponding analog signal, which is then converted into digital signal after digital / analog signal conversion.

[0055] To further optimize the solution, in the I-Scan data analysis software, under the action of pressure, each pressure measuring unit will display the corresponding digital signal DO output value. After calibration, the functional relationship between DO value and pressure value can be established.

[0056] S4. Pour the concrete according to the designed mix ratio and vibrate during the pouring process to remove the residual air inside;

[0057] During the pouring process, the uniformity and continuity of the concrete must be ensured to avoid quality defects of the segments caused by insufficient vibration or insufficient time.

[0058] Control the pouring speed and adopt layered pouring, with the thickness of each layer controlled at about 20cm to better expel bubbles and ensure the density of concrete.

[0059] S5. After pouring, steam curing is used to accelerate the hardening of concrete, and the temperature and humidity are controlled to ensure the steady development of concrete strength;

[0060] By providing suitable temperature and humidity, the hardening process of concrete can be significantly accelerated, the curing time can be shortened, and the early strength of concrete can be improved.

[0061] To further optimize the solution, maintaining the relative humidity above 90% can keep the concrete surface moist, thus avoiding the occurrence of shrinkage cracks.

[0062] To further optimize the plan, preheating stage: before pouring concrete, gradually increase the temperature of the curing room to 30°C, which generally lasts for 1-2 hours; heating stage: after pouring concrete, gradually increase the temperature of the curing room to the predetermined curing temperature, which is generally 50°C to 80°C, and the heating time is generally 2-3 hours; constant temperature stage: after reaching the predetermined curing temperature of 50°C to 80°C, maintain the constant temperature for 6-12 hours to accelerate the hardening of the concrete under constant temperature and humidity conditions; cooling stage: stop inputting steam into the curing room, and gradually reduce the temperature to room temperature, and the cooling time generally lasts 2-3 hours.

[0063] S6, dismantle the mold for demoulding, trimming, and place in a water pool for curing;

[0064] When demoulding the pipe segment, use a thermometer to measure the temperature inside the bolt hole of the pipe segment. If the temperature difference does not exceed 20°C, demoulding can be carried out.

[0065] To further optimize the solution, loosen the fixing bolts of the grouting holes, open the mold side template and mold end plate in turn, and demould the pipe segments connected by the hoist. The pipe segments are hoisted to the flipping machine and turned 90 degrees, and then the special hoist is used to hoist the side-standing pipe segments to the flatbed truck. It is strictly forbidden to hit or knock the pipe segments during the demoulding process to damage them.

[0066] To further optimize the scheme, the surface damage of the segment should be reduced during demoulding and demoulding, and soft rubber pads should be used to protect the segment when necessary. The demoulding should be carried out from top to bottom and from outside to inside to ensure a smooth and orderly demoulding process.

[0067] To further optimize the plan, after the pipe segment is demoulded, the outer surface of the pipe segment is trimmed. When repairing, use a foam sponge block dipped in cement mortar to apply it, and then smooth it with a putty spoon.

[0068] To further optimize the scheme, fill the curing pool with tap water and add water at any time to keep the water level constant to immerse the specimens. The curing time is generally 3-7 days, and the temperature is controlled at 20℃±1℃.

[0069] S7. Complete the inspection of finished products to ensure they meet the factory quality standards;

[0070] Check whether there are cracks, bubbles and other defects on the surface of the pipe segment. The surface should be kept flat and smooth without obvious defects. Check whether the length, width, height, wall thickness and other dimensions of the pipe segment meet the design requirements. The dimensional deviation should be within the allowable range. Use X-ray to detect whether the steel bar configuration inside the pipe segment meets the design requirements. Check whether the compressive strength, bending strength and other aspects of the pipe segment meet the requirements of the specifications.

[0071] After the inspection, prepare the inspection report, summarize all the results, and mark the unqualified segments

[0072] S8. Transfer qualified pipe segments to the storage area, record their numbers and wait for transportation to the construction site.

[0073] Label qualified segments and number them, indicating production date, inspection results, etc. Use a forklift to smoothly transfer the segments to the storage area to avoid collision and damage.

[0074] Further optimize the plan to keep the storage area comfortable, dry and well ventilated, and reduce humidity and sunlight.

[0075] To further optimize the solution, plastic film is laid on the floor of the storage area to prevent moisture penetration.

[0076] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A method for visualizing internal forces in an assembled lining, characterized in that: The following steps are involved: S1. Assemble the corresponding prefabricated segment molds according to the different cross-sectional shapes of the tunnel; S2. Make the steel skeleton according to the design specifications to ensure the correct connection between the steel bars and the mold; S3. Select a film pressure sensor with a suitable working range and temperature range, and cover it on the surface of the steel skeleton to monitor the pressure changes inside the prefabricated segment in real time; S4. Pour the concrete according to the designed mix ratio and vibrate during the pouring process to remove the residual air inside; S5. After pouring, steam curing is used to accelerate the hardening of concrete, and the temperature and humidity are controlled to ensure steady development of concrete strength; S6, dismantle the mold for demoulding, trimming, and place in a water pool for curing; S7. Complete the inspection of finished products to ensure they meet the factory quality standards; S8. Transfer qualified pipe segments to the storage area, record their numbers and wait for transportation to the construction site.

2. The method for visualizing internal forces of an assembled lining according to claim 1, characterized in that: In S1, the prefabricated segment mold is made of mold steel and consists of a bottom plate, four side plates and two upper covers, which can meet the needs of tunnels with different diameters and cross-sectional shapes.

3. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S2, a bracket or fixture is used to fix the steel skeleton in the mold to prevent displacement during pouring.

4. The method for visualizing internal forces of an assembled lining according to claim 1, characterized in that: In S3, the main structure of the thin film pressure sensor is a layer of semiconductor piezoelectric material wrapped in two layers of polyester insulating outer surface. The overall thickness is only 0.2mm, the working range is 10000N, and the maximum working temperature can reach 100℃.

5. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S3, two groups of vertically intersecting strips of piezoelectric materials in the piezoelectric material layer form a complete grid, each grid node is a pressure measuring unit, and each unit size is 20mm×20mm. The horizontal and vertical layout dimensions can be customized according to the size and spacing of the steel bars, and the surface of the steel bars can be covered.

6. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S3, in order to avoid loose bonding between the outer surfaces of the polyester insulation under long-term monitoring conditions, the sensor is packaged, that is, epoxy resin is used as a bonding agent.

7. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S3, silver wires for transmitting signals are sprayed on the inner wall of the polyester material to connect the piezoelectric material layer with the signal connection component, and the signal connection component transmits, reads and processes signals by connecting to an external circuit.

8. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S5, steam curing uses the heat and humidity provided by steam to accelerate the cement hydration reaction in concrete, which includes four stages: preheating stage, heating stage, constant temperature stage and cooling stage.

9. The method for visualizing internal forces of prefabricated lining according to claim 1, characterized in that: In S6, the surface of the segment should be protected from damage during demoulding and demoulding. If necessary, soft rubber pads should be used to protect the segment. The demoulding should be carried out from top to bottom and from outside to inside to ensure a smooth and orderly demoulding process.

10. An assembled lining device with visualized internal forces, characterized in that: The invention comprises a prefabricated pipe segment (7) and a steel frame (8), wherein a thin film pressure sensor (9) is arranged on the steel frame (8), the thin film pressure sensor (9) comprises a polyester material upper surface (1) and a polyester material lower surface (2), signal transmission silver wires (4) and a piezoelectric material layer (3) are arranged on the opposite surfaces of the polyester material upper surface (1) and the polyester material lower surface (2), a signal connection component (6) matching the signal transmission silver wire (4) is arranged at one end of the opposite surfaces of the polyester material upper surface (1) and the polyester material lower surface (2), a pressure measuring unit (5) is arranged on the signal transmission silver wire (4) and the piezoelectric material layer (3), and a pin (10) is arranged at one end of the thin film pressure sensor (9).

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