Subsea shield tunnel segment shear stress monitoring device and method based on metamaterials

Abstract

The application discloses a kind of based on sea bottom shield tunnel segment shear stress monitoring device and method of material, monitoring device includes shear stress sensor and shear stress monitoring host, shear stress sensor is encapsulated at the edge of sea bottom shield tunnel segment, shear stress sensor includes fixed plate, pressure plate and the multiple oblique and parallel rib strips connected between fixed plate and pressure plate, multiple rib strips are made of five-mode super material, each strain gauge is respectively arranged on the outer wall of corresponding rib strip and is connected with shear stress monitoring host wireless communication.The shear stress sensor for monitoring segment shear stress is encapsulated at the edge of sea bottom shield tunnel segment, and is made of five-mode super material, greatly improves the life and cycle of monitoring, truly realizes intelligent embedding, signal conversion sensing and distributed real-time monitoring sea bottom shield tunnel segment monitoring process.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology for submarine shield tunnel construction, specifically a device and method for monitoring the shear stress of submarine shield tunnel segments based on metamaterials. Background Technology

[0002] As the core load-bearing and waterproof component of the tunnel structure system, the mechanical state of the subsea shield tunnel segment lining directly affects the long-term safety and durability of the project. During shield tunnel construction, the shear stress borne by the segment structure is mainly generated during the construction phase. In this phase, the segments are assembled piece by piece to form a ring. As the shield advances, its enormous jacking force acts as a reaction force directly on the assembled segment ring. If the shield machine maintains a single-direction rotation for an extended period during rock-breaking, this rotational torque will be continuously transmitted to the assembled segment ring through the contact surface between the shield machine shell and the segments, causing unexpected torsional displacement of the entire ring. This torsion will generate additional shear stress in the circumferential and longitudinal joints between the segments. When the shear stress exceeds the design threshold or the shear resistance of the segment concrete, a series of problems will arise. Therefore, real-time monitoring of changes in shear stress between segments becomes a crucial construction control measure. By analyzing monitoring data, construction personnel can dynamically and timely adjust the rotation direction of the tunnel boring machine (TBM) or take other corrective measures to proactively balance its torsional trend. This effectively avoids excessive concentrated shear stress on the tunnel segments caused by prolonged unidirectional rotation, thereby preventing various tunnel quality defects, the most typical and common of which are leakage problems caused by segment joint opening and insufficient compaction of waterstop strips. It also reduces potential risks such as segment misalignment and cracking, ensuring the long-term stability and safety of the tunnel structure. Therefore, shear stress monitoring is a core component of building an intelligent operation and maintenance and safety early warning system for subsea tunnels, and is the cornerstone for achieving controllable risks throughout the entire project lifecycle and ensuring its safe service life for a century.

[0003] However, the components used for monitoring the shear stress of submarine shield tunnel segments often have a short service life, and they are installed on the outside of the segments, making it impossible to integrate them with the existing segments, thus resulting in a short service life. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a shear stress monitoring device and method for subsea shield tunnel segments based on metamaterials. The shear stress sensor for monitoring the shear stress of the segments is encapsulated at the edge of the subsea shield tunnel segments and is made of five-mode metamaterials, which greatly improves the monitoring life and cycle, and truly realizes the monitoring process of intelligent embedding, signal conversion sensing and distributed real-time monitoring of subsea shield tunnel segments.

[0005] The technical solution of this invention is as follows:

[0006] The shear stress monitoring device for submarine shield tunnel segments based on metamaterials includes a shear stress sensor and a shear stress monitoring host. The shear stress sensor is encapsulated at the edge of the submarine shield tunnel segment and is wirelessly connected to the shear stress monitoring host.

[0007] The shear stress sensor includes a fixed plate, a bearing plate, multiple ribs, and multiple strain gauges. The fixed plate and the bearing plate are arranged parallel to each other vertically. The multiple ribs are arranged parallel to each other with equal spacing. The top end of each rib is fixedly connected to the bearing plate, and the bottom end of each rib is fixedly connected to the fixed plate. In the unloaded state, the angle between the rib and the fixed plate is [value missing]. Each strain gauge is set on the outer wall of a corresponding rib. When the shear stress sensor is encapsulated at the edge of the submarine shield tunnel segment, the top of the pressure plate extends out from the plane at the edge of the submarine shield tunnel segment.

[0008] The multiple ribs are all five-mode metamaterials, each rib is composed of multiple microstructure units, and each microstructure unit is composed of four prismatic cells. The prismatic cell is a structure formed by the bottom surfaces of two cones touching. In each microstructure unit, one prismatic cell is set vertically, and the other three prismatic cells form a tripod support structure with their top ends touching the bottom end of one of the prismatic cells. In the five-mode metamaterial, any two adjacent prismatic cells are connected to form a node. The middle part of each rib is a solid structure, that is, the multiple microstructure units in the middle of the rib are covered with encapsulating material, and each strain gauge is set on the outer wall of the middle part of the corresponding rib.

[0009] The prismatic unit cell is a nickel-titanium shape memory alloy unit cell. When the prismatic unit cell is vertically arranged, the diameter of the central cross-section is... The cross-sectional diameters at 1 / 4 and 3 / 4 of the height are both , , The value range is 0.45-0.65.

[0010] The encapsulation material in the middle of the rib is epoxy resin with a modulus range of 2.1-3.2 GPa. The cross-section of the middle part of the rib is circular, and the length of the middle part of the rib is... The upper and lower parts of the ribs are of equal length. , , The value range is 1.8-3.2.

[0011] The shear stress sensor uses 1 / 4 bridge strain gauges for all its strain gauges.

[0012] The fixing plate and the bearing plate of the shear stress sensor are both aluminum alloy plates. The area between the fixing plate and the bearing plate is filled with a rubber filling layer. Multiple ribs are completely covered in the rubber filling layer, so that the shear stress sensor forms a complete columnar structure.

[0013] The shear stress sensor has an odd number of ribs. Temperature sensing probes are installed on the two ribs on either side of the middle rib. Except for the middle rib and the two ribs with temperature sensing probes, strain gauges are installed on the other ribs.

[0014] The shear stress sensor is wirelessly connected to the shear stress monitoring host via a data processing module. When the shear stress sensor is encapsulated at the edge of a submarine shield tunnel segment, a groove is first cut into the plane at the edge of the submarine shield tunnel segment. Then, the shear stress sensor and the data processing module are placed in the groove, with the top of the pressure plate extending outward from the plane at the edge of the submarine shield tunnel segment. Finally, a filling material with a modulus greater than 32 GPa and less than 35 GPa is filled into the groove and cured. The data processing module includes a microcontroller, a data acquisition module connected to the microcontroller, and a wireless communication module. Multiple strain gauges are connected to the data acquisition module via signal lines, and the wireless communication module is wirelessly connected to the shear stress monitoring host.

[0015] The method for monitoring shear stress in subsea shield tunnel segments includes the following steps:

[0016] (1) The strain measured by each strain gauge on the shear stress sensor The following formula (1) is used to calculate:

[0017] (1);

[0018] In equation (1), The strain transfer coefficient has a value range of 0.85-0.95. This represents the change in resistance of the strain gauge; This represents the strain gauge sensitivity coefficient; This represents the initial resistance value of the strain gauge;

[0019] (2) The horizontal shear stress measured by each strain gauge on the shear stress sensor The following formula (2) is used to calculate:

[0020] (2);

[0021] In equation (2), This is an adjustment coefficient, with a value range of 1.31-1.65; The strain represents the strain measured by the strain gauge; Represents the diameter of the cross section of the prismatic unit cell and cross-sectional diameter The mean; Let be the moment of inertia of the rib section; The modulus of the encapsulating material in the middle of the rib; Represents the horizontal spacing between adjacent ribs; Represents the radius of the rib; The mixed elastic modulus representing the middle part of the rib is calculated by the following formula (3):

[0022] (3);

[0023] In equation (3), and All are specific gravity coefficients. The value range is 0.82-0.93. The value range is 0.13-0.23. The modulus of the encapsulating material in the middle of the rib. The modulus of the nickel-titanium shape memory alloy unit cell;

[0024] (3) Sum the horizontal shear stresses measured by multiple strain gauges on the shear stress sensor and calculate the average value, and use the calculated average value as the shear stress monitoring value of the pipe segment collected by the shear stress sensor.

[0025] The shear stress sensor is equipped with a temperature sensing probe. The shear stress collected by the shear stress sensor is temperature-compensated by the temperature collected by the temperature sensing probe on the shear stress sensor, and is used as the final shear stress monitoring value of the tunnel segment.

[0026] Advantages of this invention:

[0027] (1) The shear stress sensor of the present invention for monitoring the shear stress of the tunnel segments is encapsulated at the edge of the tunnel segments of the submarine shield tunnel, so as to realize the acquisition of shear stress between the circumferential joints and longitudinal joints between the tunnel segments. The shear stress sensor is encapsulated in the tunnel segments of the submarine shield tunnel, and is an integral structure with the tunnel segments of the submarine shield tunnel, which greatly improves the monitoring life and cycle.

[0028] (2) The ribs in the shear stress sensor of the present invention are made of five-mode metamaterial, which is resistant to compression but not to shear. That is, when the five-mode metamaterial is subjected to a vertical load, the five-mode metamaterial will not deform. When the five-mode metamaterial is subjected to horizontal shear stress, it will exhibit obvious torsion. Therefore, by collecting horizontal shear stress through this strain sensor, compared with conventional capacitive shear stress sensor, its structure is more suitable for long-term monitoring of tunnel segments in harsh environments.

[0029] (3) The strain gauge on the shear stress sensor of the present invention is affected by low temperature. Therefore, a temperature sensing probe is integrated on the shear stress sensor. By collecting the temperature, the collected shear stress of the tube segment is compensated for temperature, so that the final collected shear stress data is more accurate.

[0030] (4) The cell in the five-mode metamaterial of the present invention is a nickel-titanium shape memory alloy cell, which has the function of shape memory. When subjected to pressure, it can make a rapid response and can quickly recover to its original shape after the deformation is completed, which greatly improves the service life.

[0031] (5) The shear stress sensor of the present invention is provided with multiple ribs with strain gauges, thereby collecting multiple shear stress values ​​and averaging them, so that the shear stress data collected by the shear stress sensor is more realistic and accurate. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the shear stress sensor of the present invention encapsulated at the arc-shaped edge of a submarine shield tunnel segment.

[0033] Figure 2 This is a partial schematic diagram of the shear stress sensor of the present invention encapsulated in a submarine shield tunnel segment.

[0034] Figure 3 This is a schematic diagram of the shear stress sensor of the present invention in an unstressed state.

[0035] Figure 4 This is a schematic diagram of the structure of the shear stress sensor of the present invention after deformation under horizontal shear stress.

[0036] Figure 5 This is a schematic diagram of the structure of a single rib on the shear stress sensor of the present invention.

[0037] Figure 6 This is a schematic diagram of the prismatic cell structure in the five-mode metamaterial of this invention.

[0038] Reference numerals: 1-submarine shield tunnel segment, 2-shear stress sensor, 21-fixing plate, 22-pressure bearing plate, 23-rib, 24-strain gauge, 25-rubber filler layer, 31-prismatic cell, 32-node, 33-epoxy resin, 4-polyvinyl alcohol fiber, 5-data processing module. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] See Figures 1-4 A metamaterial-based shear stress monitoring device for subsea shield tunnel segments includes a shear stress sensor 2 and a shear stress monitoring host. The shear stress sensor 2 is encapsulated at the arc-shaped edge of the subsea shield tunnel segment 1 (see...). Figure 1 Furthermore, it is wirelessly connected to the shear stress monitoring host via the data processing module 5 to monitor the shear stress between the annular joints of the subsea shield tunnel segment 1.

[0041] The shear stress sensor 2 includes a fixed plate 21, a pressure plate 22, seven ribs 23, four strain gauges 24, two temperature sensing probes, and a rubber filling layer 25. Both the fixed plate 21 and the pressure plate 22 are aluminum alloy plates, arranged parallel to each other vertically. The seven ribs 23 are arranged parallel to each other with equal spacing. The top of each rib 23 is fixedly connected to the pressure plate 22, and the bottom of each rib 23 is fixedly connected to the fixed plate 21. In the unloaded state, the angle between the ribs 23 and the fixed plate 21 is [value missing]. Temperature sensing probes are installed on the two ribs 23 (C and E) on both sides of the middle rib. Except for the middle rib and the two ribs with temperature sensing probes, strain gauges 24 are installed on the other four ribs 23 (A, B, F and G). The strain gauges 24 are 1 / 4 bridge strain gauges. The area between the fixed plate 21 and the bearing plate 22 is filled with a rubber filling layer 25. The seven ribs 23 are completely covered in the rubber filling layer 25, so that the shear stress sensor 2 forms a complete columnar structure.

[0042] See Figure 5 and Figure 6 All seven ribs 23 are five-mode metamaterials, each rib 23 is composed of multiple microstructure units, and each microstructure unit is composed of four prismatic cells 31. Each prismatic cell 31 is a structure formed by the bottom surfaces of two cones joined together. The prismatic cells 31 are nickel-titanium shape memory alloy cells. When the prismatic cells 31 are vertically arranged, the diameter of the central cross-section is... The cross-sectional diameters at 1 / 4 and 3 / 4 of the height are both , , The value range is 0.45-0.65; in each microstructure unit, one prismatic cell 31 is vertically arranged, and the other three prismatic cells 31 form a tripod support structure with their top ends connected to the bottom end of one of the prismatic cells 31; in the five-mode metamaterial, any two adjacent prismatic cells 31 are connected to form a node 32; the middle part of each rib 23 is a solid structure, that is, multiple microstructure units in the middle of the rib 23 are covered with epoxy resin 33 with a modulus range of 2.1-3.2 GPa, the cross-section of the middle part of the rib 23 is circular, and the length of the middle part of the rib 23 is The upper and lower parts of rib 23 are both hollow structures composed of rhombic unit cells, and the upper and lower parts of rib 23 are of equal length. , , The value range is 1.8-3.2; each strain gauge 24 is set on the outer wall of the middle part of the corresponding rib 23.

[0043] See Figure 2 When the shear stress sensor is encapsulated at the edge of the submarine shield tunnel segment, a groove is first cut on the plane at the edge of the submarine shield tunnel segment. Then, the shear stress sensor and the data processing module 5 are placed in the groove, and the top of the pressure plate 22 extends out from the plane at the edge of the submarine shield tunnel segment 1. Finally, polyvinyl alcohol fiber 4 is filled into the groove and cured. The data processing module 5 includes a microcontroller, a data acquisition module and a wireless communication module connected to the microcontroller. The four strain gauges 24 and the two temperature sensing probes are all connected to the data acquisition module through signal lines. The wireless communication module is wirelessly connected to the shear stress monitoring host.

[0044] The method for monitoring shear stress in subsea shield tunnel segments based on metamaterials includes the following steps:

[0045] (1) The strain measured by each strain gauge 24 on the shear stress sensor 2 The following formula (1) is used to calculate:

[0046] (1);

[0047] In equation (1), The strain transfer coefficient has a value range of 0.85-0.95. This represents the change in resistance of the strain gauge; This represents the strain gauge sensitivity coefficient; This represents the initial resistance value of the strain gauge;

[0048] (2) The horizontal shear stress measured by each strain gauge 24 on the shear stress sensor 2 The following formula (2) is used to calculate:

[0049] (2);

[0050] In equation (2), This is an adjustment coefficient, with a value range of 1.31-1.65; The strain represents the strain measured by the strain gauge; Represents the diameter of the cross section of the prismatic unit cell and cross-sectional diameter The mean; Let be the moment of inertia of the rib section; The modulus of the epoxy resin in the middle of the rib; Represents the horizontal spacing between adjacent ribs; Represents the radius of the rib; The mixed elastic modulus representing the middle part of the rib is calculated by the following formula (3):

[0051] (3);

[0052] In equation (3), and All are specific gravity coefficients. The value range is 0.82-0.93. The value range is 0.13-0.23. This refers to the modulus of the epoxy resin in the middle of the rib. The modulus of the nickel-titanium shape memory alloy unit cell;

[0053] (3) The horizontal shear stresses measured by the four strain gauges 24 on the shear stress sensor 2 are summed and averaged. The shear stress sensor 2 is equipped with a temperature sensing probe. The average value of the values ​​collected by the four strain gauges 24 is compensated for by the temperature collected by the temperature sensing probe on the shear stress sensor 2, and is used as the final shear stress monitoring value of the tube segment.

[0054] When monitoring the shear stress of tunnel segments, the shear stress sensor 2 is mainly deployed on the submarine shield tunnel segments 1 at key nodes in areas with adverse geological conditions, such as the fracture zone and water inrush area of ​​the tunnel.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A monitoring device for shear stress of subsea shield tunnel segments based on metamaterials, characterized in that: It includes a shear stress sensor and a shear stress monitoring host. The shear stress sensor is encapsulated at the edge of the subsea shield tunnel segment and is wirelessly connected to the shear stress monitoring host. The shear stress sensor includes a fixed plate, a pressure plate, multiple ribs, and multiple strain gauges. The fixed plate and the pressure plate are arranged parallel to each other vertically. The multiple ribs are arranged parallel to each other with equal spacing. The top end of each rib is fixedly connected to the pressure plate, and the bottom end of each rib is fixedly connected to the fixed plate. In the unstressed state, the angle between the rib and the fixed plate is 34.5-63.2°. Each strain gauge is set on the outer wall of a corresponding rib. When the shear stress sensor is encapsulated at the edge of the submarine shield tunnel segment, the top of the pressure plate extends outward from the plane at the edge of the submarine shield tunnel segment. The multiple ribs are all five-mode metamaterials, each rib is composed of multiple microstructure units, and each microstructure unit is composed of four prismatic cells. The prismatic cell is a structure formed by the bottom surfaces of two cones touching. In each microstructure unit, one prismatic cell is set vertically, and the other three prismatic cells form a tripod support structure with their top ends touching the bottom end of one of the prismatic cells. In the five-mode metamaterial, any two adjacent prismatic cells are connected to form a node. The middle part of each rib is a solid structure, that is, the multiple microstructure units in the middle of the rib are covered with encapsulating material, and each strain gauge is set on the outer wall of the middle part of the corresponding rib.

2. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The prismatic unit cell is a nickel-titanium shape memory alloy unit cell. When the prismatic unit cell is vertically arranged, the diameter of the central cross-section is... The cross-sectional diameters at 1 / 4 and 3 / 4 of the height are both , , The value range is 0.45-0.

65.

3. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The encapsulation material in the middle of the rib is epoxy resin with a modulus range of 2.1-3.2 GPa. The cross-section of the middle part of the rib is circular, and the length of the middle part of the rib is... The upper and lower parts of the ribs are of equal length. , , The value range is 1.8-3.

2.

4. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The shear stress sensor uses 1 / 4 bridge strain gauges for all its strain gauges.

5. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The fixing plate and the bearing plate of the shear stress sensor are both aluminum alloy plates. The area between the fixing plate and the bearing plate is filled with a rubber filling layer. Multiple ribs are completely covered in the rubber filling layer, so that the shear stress sensor forms a complete columnar structure.

6. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The shear stress sensor has an odd number of ribs. Temperature sensing probes are installed on the two ribs on either side of the middle rib. Except for the middle rib and the two ribs with temperature sensing probes, strain gauges are installed on the other ribs.

7. The metamaterial-based subsea shield tunnel segment shear stress monitoring device according to claim 1, characterized in that: The shear stress sensor is wirelessly connected to the shear stress monitoring host via a data processing module. When the shear stress sensor is encapsulated at the edge of a submarine shield tunnel segment, a groove is first cut into the plane at the edge of the submarine shield tunnel segment. Then, the shear stress sensor and the data processing module are placed in the groove, with the top of the pressure plate extending outward from the plane at the edge of the submarine shield tunnel segment. Finally, a filling material with a modulus greater than 32 GPa and less than 35 GPa is filled into the groove and cured. The data processing module includes a microcontroller, a data acquisition module connected to the microcontroller, and a wireless communication module. Multiple strain gauges are connected to the data acquisition module via signal lines, and the wireless communication module is wirelessly connected to the shear stress monitoring host.

8. A shear stress monitoring method based on the shear stress monitoring device for subsea shield tunnel segments according to claim 2, characterized in that: Specifically, it includes the following steps: (1) The strain measured by each strain gauge on the shear stress sensor The following formula (1) is used to calculate: （1）； In equation (1), The strain transfer coefficient has a value range of 0.85-0.

95. This represents the change in resistance of the strain gauge; This represents the strain gauge sensitivity coefficient; This represents the initial resistance value of the strain gauge; (2) The horizontal shear stress measured by each strain gauge on the shear stress sensor The following formula (2) is used to calculate: （2）； In equation (2), This is an adjustment coefficient, with a value range of 1.31-1.65; Represents the strain measured by the strain gauge; Represents the diameter of the cross section of the prismatic unit cell and cross-sectional diameter The mean; Let be the moment of inertia of the rib section; The modulus of the encapsulating material in the middle of the rib; Represents the horizontal spacing between adjacent ribs; Represents the radius of the rib; The mixed elastic modulus representing the middle part of the rib is calculated by the following formula (3): （3）； In equation (3), and All are specific gravity coefficients. The value range is 0.82-0.

93. The value range is 0.13-0.

23. The modulus of the encapsulating material in the middle of the rib. The modulus of the nickel-titanium shape memory alloy unit cell; (3) Sum the horizontal shear stresses measured by multiple strain gauges on the shear stress sensor and calculate the average value, and use the calculated average value as the shear stress monitoring value of the pipe segment collected by the shear stress sensor.

9. The shear stress monitoring method according to claim 8, characterized in that: The shear stress sensor is equipped with a temperature sensing probe. The shear stress collected by the shear stress sensor is temperature-compensated by the temperature collected by the temperature sensing probe on the shear stress sensor, and is used as the final shear stress monitoring value of the tunnel segment.

Images