Shield tunnel segment monitoring and early warning device and method

Abstract

The application discloses a shield tunnel segment monitoring and early warning device and method, and belongs to the technical field of shield tunnel structure safety monitoring. The method comprises the following steps: acquiring pressure detection values at multiple pressure detection positions in a segment joint contact surface; determining effective pressure-bearing area variation characteristics, pressure action position variation characteristics and local pressure variation characteristics according to the spatial distribution of the pressure detection values on the segment joint contact surface under different detection states; identifying the bearing state of the segment joint according to the effective pressure-bearing area variation characteristics, the pressure action position variation characteristics and the local pressure variation characteristics, and outputting corresponding early warning information according to the identified bearing state. The method can characterize the load transmission of the segment joint from the effective pressure-bearing area variation, the pressure action position variation and the local pressure variation, thereby helping to judge the bearing state of the segment joint and output early warning information corresponding to the bearing state.

Description

Technical Field

[0001] This application relates to the field of tunnel engineering technology, and in particular to a device and method for monitoring and early warning of shield tunnel segments. Background Technology

[0002] Shield tunneling is characterized by its high degree of automation and minimal impact on the surrounding environment, and is widely used in the construction of tunnels for subways, river-crossing passages, and municipal utility tunnels. Shield tunnels typically use prefabricated segments assembled into rings. Adjacent segments contact each other and transfer loads through the joints, which are crucial components of the segment lining structure for load transfer.

[0003] The segment joints employ a prefabricated connection method, resulting in a discontinuous contact state between adjacent segments. During tunnel construction and operation, factors such as changes in external loads, ground displacement, and assembly quality can alter the contact state of the segment joints. For example, some areas within the joint contact surface may change from a contact state to a detached state, or the load distribution within the contact surface may change. These changes directly affect load transfer at the segment joints, thus impacting the structural safety of the segment lining. Therefore, monitoring the stress conditions of the segment joints is crucial during shield tunnel construction and operation. In related technologies, pressure sensors are typically installed at the segment joints to collect pressure readings and monitor the stress conditions.

[0004] However, the above monitoring methods can generally only obtain the pressure value at the joint, which is difficult to reflect the distribution and changes of pressure in the contact surface of the segment joint, thus making it difficult to judge the load-bearing state of the segment joint. Summary of the Invention

[0005] In view of the problems of the prior art, and in order to help determine the load-bearing status of the tunnel segment joints, this application provides a shield tunnel segment monitoring and early warning device and method.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: A method for monitoring and early warning of shield tunnel segments is provided, including: Obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint; Based on the spatial distribution of the pressure detection values ​​under different detection states on the contact surface of the segment joint, the characteristics of the effective pressure-bearing area variation, the characteristics of the pressure application location variation, and the characteristics of the local pressure variation are determined; wherein, the effective pressure-bearing area is the pressure application area where the pressure detection values ​​meet the preset pressure-bearing conditions, and the pressure application location is determined by the pressure application center; Based on the characteristics of the effective pressure-bearing area change, the characteristics of the pressure application location change, and the characteristics of the local pressure change, the bearing state of the segment joint is identified, and corresponding early warning information is output according to the identified bearing state; wherein, the bearing state includes the effective contact area change state, the bias state, the pressure concentration state, and the pressure distribution stable state.

[0007] Furthermore, the step of obtaining pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint includes: Based on the range of the contact area of ​​the segment joint, multiple pressure detection positions are set within the contact surface of the segment joint; Before assembling the tunnel segments, pressure detection devices are installed at each of the pressure detection positions, and the pressure-sensing surface of the pressure detection device is in contact with the joint surface of the tunnel segment. During the contact process between adjacent segments after segment assembly, the contact pressure at each pressure detection position is collected by the pressure detection device to obtain the pressure detection value at each pressure detection position, and the spatial coordinates of each pressure detection position within the contact surface of the segment joint are recorded simultaneously.

[0008] Furthermore, the pressure detection device is a thin-film pressure sensor.

[0009] Furthermore, in the step of determining the effective pressure-bearing area variation characteristics, pressure application location variation characteristics, and local pressure variation characteristics based on the spatial distribution of the pressure detection values ​​under different detection states on the contact surface of the segment joint, the method for determining the effective pressure-bearing area variation characteristics includes: Based on the spatial coordinates of each pressure detection position, the contact surface of the segment joint is spatially divided, and the contact area within the range corresponding to each pressure detection position is determined as the pressure action area, with each pressure detection position corresponding to a pressure action area. The pressure detection values ​​at each pressure detection location are mapped to the corresponding pressure application area, and the effective pressure-bearing determination parameter for each pressure application area is determined based on the pressure detection value corresponding to each pressure application area and the preset pressure-bearing determination value. When the pressure detection value corresponding to the pressure application area is not less than the preset pressure-bearing determination value, the effective pressure-bearing determination parameter is 1; when the pressure detection value corresponding to the pressure application area is less than the preset pressure-bearing determination value, the effective pressure-bearing determination parameter is 0. The pressure-bearing area where the effective pressure-bearing determination parameter is 1 is defined as the effective pressure-bearing area. Based on the changes in the number, distribution range, and area of ​​the effective pressure-bearing area under different detection conditions, the change characteristics of the effective pressure-bearing area are determined.

[0010] Furthermore, the preset pressure-bearing judgment value is determined based on the structural parameters of the segment joint, the design bearing requirements, and the stress conditions; the area of ​​the effective pressure-bearing region is the sum of the products of each of the effective pressure-bearing judgment parameters and the area of ​​the corresponding pressure-acting region.

[0011] Furthermore, in the step of determining the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation based on the spatial distribution of the pressure detection values ​​under different detection states on the contact surface of the segment joint, the method for determining the pressure application location variation characteristics includes: Based on the pressure detection value, area, and center coordinates of each pressure-affected area, the center coordinates of each pressure-affected area are weighted using the product of the pressure detection value and area as the weight to obtain the pressure center. Record the positional relationship between the pressure center and the stress center of the segment joint under the initial stable state, and compare the positional relationship between the pressure center and the stress center of the segment joint under the subsequent detection state with the positional relationship recorded under the initial stable state. Determine the pressure position change characteristics based on the comparison results.

[0012] Furthermore, in the step of determining the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation based on the spatial distribution of the pressure detection values ​​under different detection states on the contact surface of the segment joint, the method for determining the local pressure variation characteristics includes: Based on the comparison between the pressure detection values ​​corresponding to each pressure application area and the pressure detection values ​​corresponding to adjacent pressure application areas, local pressure change characteristics are determined; the local pressure change characteristics include: when the pressure detection value corresponding to the local pressure application area exceeds the preset normal pressure distribution range and is higher than the pressure detection value corresponding to the adjacent pressure application area, the load is concentrated and transferred to the local pressure application area.

[0013] Furthermore, the preset normal pressure distribution range is determined based on the pressure action area at the corresponding position under the initial stable state and the pressure distribution of the adjacent pressure action areas.

[0014] Furthermore, the step of identifying the bearing state of the segment joint based on the variation characteristics of the effective pressure-bearing area, the variation characteristics of the pressure application location, and the local pressure variation characteristics includes: When at least one of the number, distribution range and area of ​​the effective pressure-bearing area changes, it is determined that the area of ​​the segment joint that actually participates in load transfer has changed, and this is identified as a change in the effective contact area. When the position of the pressure center relative to the stress center of the segment joint changes, it is determined that the load transfer area of ​​the segment joint has shifted, and this is identified as the bias state. When the pressure detection value corresponding to the local pressure area increases beyond the preset normal pressure distribution range relative to the adjacent pressure area, it is determined that the load is concentrated and transferred to the local pressure area, and it is identified as the pressure concentration state. When the effective pressure-bearing area, the pressure center, and the local pressure distribution remain unchanged during continuous detection, it is identified as a stable pressure distribution state. When the same detection state has multiple pressure spatial distribution characteristics, the identified bearing state includes the state corresponding to each of the pressure spatial distribution characteristics. When the same detection state has multiple characteristics among the effective pressure-bearing area variation characteristics, pressure application location variation characteristics, and local pressure variation characteristics, the identified bearing state includes the state corresponding to each of the characteristics.

[0015] On the other hand, this application also provides a shield tunnel segment monitoring and early warning device, including a pressure detection module, a pressure distribution construction module, a status identification module and an early warning module; The pressure detection module is located inside the contact surface of the segment joint and is used to obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint and send the pressure detection values ​​to the pressure distribution construction module. The pressure distribution construction module is connected to the pressure detection module and is used to determine the effective pressure-bearing area change characteristics, pressure application location change characteristics, and local pressure change characteristics based on the spatial distribution of each pressure detection value on the contact surface of the segment joint under different detection states. The effective pressure-bearing area change characteristics, pressure application location change characteristics, and local pressure change characteristics are then sent to the state recognition module. The effective pressure-bearing area is the pressure application area where the pressure detection value meets the preset pressure-bearing conditions, and the pressure application location is determined by the pressure application center. The state recognition module is connected to the pressure distribution construction module and is used to identify the bearing state of the segment joint based on the effective pressure bearing area change characteristics, the pressure application location change characteristics, and the local pressure change characteristics, and send the identified bearing state to the early warning module; the bearing state includes the effective contact area change state, the bias state, the pressure concentration state, and the pressure distribution stable state; The early warning module is connected to the status recognition module and is used to output corresponding early warning information based on the received bearer status.

[0016] In summary, the beneficial effects of this application are as follows: 1. By acquiring pressure detection values ​​at multiple pressure detection locations within the segment joint contact surface, and based on the spatial distribution of each pressure detection value on the segment joint contact surface under different detection states, the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation are determined. Furthermore, based on these three variation characteristics, the load-bearing state of the segment joint is identified, and corresponding early warning information is output. This method maps discrete pressure detection values ​​to the spatial distribution of pressure on the segment joint contact surface, characterizing the load transfer of the segment joint from three dimensions: effective pressure-bearing area variation, pressure application location variation, and local pressure variation. This helps in judging the load-bearing state of the segment joint and promptly outputs early warning information corresponding to the load-bearing state.

[0017] 2. By installing pressure detection devices at each pressure detection location before segment assembly and ensuring that the pressure-sensing surface of the pressure detection device is in contact with the segment joint, the contact pressure at each pressure detection location is collected during the contact process between adjacent segments after segment assembly, and the spatial coordinates of each pressure detection location are recorded simultaneously. This allows for the direct measurement of the contact pressure at each spatial location within the segment joint contact surface, and ensures that the collected pressure detection values ​​correspond one-to-one with the spatial locations within the contact surface, thus providing a data basis for establishing the spatial distribution of pressure.

[0018] 3. By defining the contact area within the range corresponding to each pressure detection position as the pressure application area, and comparing the pressure detection value at each pressure detection position with the preset pressure bearing judgment value, the pressure application area that is not less than the preset pressure bearing judgment value is defined as the effective pressure bearing area. Based on the changes in the number, distribution range, and area of ​​the effective pressure bearing area under different detection conditions, the variation characteristics of the effective pressure bearing area can be determined. This can help to identify the area in the segment joint that actually maintains contact and participates in load transfer, thereby helping to understand the changes in the area of ​​the segment joint that actually participates in load transfer.

[0019] 4. By using the product of the pressure detection value and the area of ​​each pressure-affected area as the weight, the center coordinates of each pressure-affected area are weighted and calculated to obtain the center of pressure. The positional relationship of the center of pressure relative to the stress center of the segment joint under subsequent detection conditions is compared with the positional relationship recorded under the initial stable state. This can transform the pressure distribution within the contact surface of the segment joint into a pressure center whose position can be quantified, thereby helping to determine whether the load transfer area of ​​the segment joint has shifted. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1This is a flowchart illustrating an optional shield tunnel segment monitoring and early warning method according to an embodiment of this application. Figure 2 This is a schematic diagram of the pressure detection location setting and pressure action area division within the contact surface of the segment joint provided in this application embodiment; Figure 3 This is a schematic diagram showing the arrangement of pressure detection values ​​corresponding to each pressure application area provided in the embodiments of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions of this application will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Shield tunnels typically employ prefabricated segments assembled into rings, with adjacent segments contacting each other and transferring loads through joint surfaces. The segment joints utilize a prefabricated connection method, resulting in a discontinuous contact state between adjacent segments. Influenced by factors such as external load variations, ground displacement, and assembly quality, the degree of contact and load transfer at different spatial locations within the joint surface vary and may change over time. To assess the load-bearing capacity of the segment joints, this application uses shield tunnel segment joints as the detection object. Multiple pressure detection locations are established within the joint contact surface to acquire pressure values ​​at each location. Based on the spatial distribution of these pressure values ​​across the joint contact surface under different detection conditions, the characteristics of effective pressure-bearing area changes, pressure application location changes, and local pressure changes are determined. This allows for the identification of the joint's load-bearing capacity and the output of corresponding early warning information.

[0023] Example 1 Reference Figure 1 In one embodiment, a method for monitoring and early warning of shield tunnel segments is provided, comprising the following steps: S1: Obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint.

[0024] Specifically, firstly, the area of ​​the tunnel segment joints to be inspected is determined, and then multiple pressure testing positions are set within the contact surface of the segment joints according to the range of the contact area. The contact area of ​​the segment joints refers to the area where adjacent segments come into contact with each other after assembly and can transfer loads. The pressure testing positions are arranged within this contact area to cover different spatial locations within the contact surface of the segment joints.

[0025] Then, before segment assembly, pressure detection devices are installed at each pressure detection location, with the pressure-sensing surface of the device in contact with the segment joint surface. This ensures that the contact pressure generated between adjacent segments after assembly can act on the pressure detection device. In one embodiment, the pressure detection device is a thin-film pressure sensor, installed at the corresponding pressure detection location, with its pressure-sensing surface in contact with the segment joint surface.

[0026] After the pressure testing device is installed, the tunnel segments are assembled. During the contact process between adjacent segments after assembly, the pressure testing device collects the contact pressure at each pressure testing location, obtaining the pressure test value at each location, and simultaneously recording the spatial coordinates of each pressure testing location within the contact surface of the segment joint. The pressure test value is the contact pressure value collected by the pressure testing device at the corresponding pressure testing location; the spatial coordinates are used to determine the spatial positional relationship of the pressure testing location within the contact surface of the segment joint, providing a positional basis for subsequently establishing the correspondence between the pressure test values ​​and the spatial area within the contact surface of the segment joint.

[0027] S2: Based on the spatial distribution of pressure detection values ​​on the contact surface of the segment joint under different detection conditions, determine the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation.

[0028] In this embodiment, the detection state refers to the state corresponding to the detection of the contact surface of the segment joint at a certain moment or under a certain load condition. Different detection states include, for example, the initial stable state, the detection state after the external load changes, and the various detection states in the continuous detection stage. The initial stable state refers to the detection state corresponding to the completion of segment assembly, the stability of the external load, and the tendency of the contact pressure distribution of the segment joint to stabilize.

[0029] The effective pressure-bearing area is the pressure-acting area where the pressure detection value meets the preset pressure-bearing conditions, and the pressure-acting location is determined by the pressure-acting center. The specific determination process of the effective pressure-bearing area variation characteristics, pressure-acting location variation characteristics, and local pressure variation characteristics are respectively referred to in steps S201 to S203 below.

[0030] S201: Determine the variation characteristics of the effective pressure-bearing area.

[0031] First, based on the spatial coordinates of each pressure detection location, the contact surface of the segment joint is spatially divided, and the contact area within the range corresponding to each pressure detection location is determined as the pressure application area. Each pressure detection location corresponds to a pressure application area. The pressure application area is used to characterize the spatial range of the pressure detection value at the corresponding pressure detection location within the contact surface of the segment joint.

[0032] By mapping the discretely acquired pressure detection values ​​to the contact area of ​​the segment joint through the correspondence between pressure detection location, spatial coordinates, pressure application area, and pressure detection value, the pressure detection values ​​are formed at different spatial locations of the segment joint, thus obtaining the spatial distribution of each pressure detection value on the contact surface of the segment joint.

[0033] Then, the pressure detection values ​​at each pressure detection location are mapped to the corresponding pressure application area, and the effective pressure application parameters for each pressure application area are determined based on the pressure detection values ​​corresponding to each pressure application area and the preset pressure application judgment values. i Effective pressure-bearing parameters for each pressure-acting area for:

[0034] in: For the first Effective pressure-bearing determination parameters for each pressure-affected area; For the first Pressure detection values ​​corresponding to each pressure application area; This is the preset pressure-bearing threshold.

[0035] When the pressure detection value corresponding to the pressure application area is not less than the preset pressure bearing judgment value, the effective pressure bearing judgment parameter is 1, and the pressure application area meets the effective pressure bearing condition; when the pressure detection value corresponding to the pressure application area is less than the preset pressure bearing judgment value, the effective pressure bearing judgment parameter is 0, and the pressure application area does not meet the effective pressure bearing condition.

[0036] The preset pressure bearing threshold is determined based on the structural parameters of the tunnel segment joint, design load-bearing requirements, and stress conditions. For example, the preset pressure bearing threshold can be determined based on the design pressure bearing value of the tunnel segment joint.

[0037] Therefore, the pressure-bearing area with an effective pressure-bearing parameter of 1 is defined as the effective pressure-bearing area. Through the above determination, the effective pressure-bearing area in the segment joint that actually maintains contact and participates in load transfer is identified.

[0038] After determining the effective pressure-bearing zone, its area is calculated. The area of ​​the effective pressure-bearing zone is the sum of the products of each effective pressure-bearing parameter and the area of ​​the corresponding pressure-acting region. The formula for calculating the area of ​​the effective pressure-bearing zone is:

[0039] in: The effective pressure-bearing area; For the first Area of ​​the pressure-affected region; This represents the number of areas affected by the pressure.

[0040] Finally, the area of ​​the effective pressure-bearing zone under different testing conditions was calculated. Based on the changes in the number, distribution range, and area of ​​the effective pressure-bearing zone under different testing conditions, the characteristics of the effective pressure-bearing zone variation were determined. When at least one of the number, distribution range, or area of ​​the effective pressure-bearing zone changes, it indicates that the area inside the segment joint that actually participates in load transfer has changed.

[0041] S202: Determine the characteristics of changes in the location of pressure application.

[0042] Based on the pressure detection value, area, and center coordinates of each pressure-affected area, the center coordinates of each pressure-affected area are weighted using the product of the pressure detection value and area as the weight, thus obtaining the pressure center. The formula for calculating the pressure center is:

[0043]

[0044] in: The coordinates of the center of pressure action; For the first Each pressure-affected area corresponds to a pressure detection value; For the first Area of ​​the pressure-affected region; For the first The coordinates of the center of the pressure zone.

[0045] In this embodiment, the stress center of the segment joint is adopted as the designed stress center of the segment joint. The positional relationship between the pressure center and the stress center of the segment joint under the initial steady state is recorded. The positional relationship between the pressure center and the stress center of the segment joint under subsequent detection states is compared with the recorded positional relationship under the initial steady state. The characteristics of the pressure position change are determined based on the comparison results. When the positional relationship between the pressure center and the stress center of the segment joint changes compared to the initial steady state, it indicates that the load transfer area inside the segment joint has shifted.

[0046] S203: Determine the characteristics of local pressure changes.

[0047] The characteristics of local pressure changes are determined by comparing the pressure readings of each pressure-affected area with those of adjacent pressure-affected areas. Adjacent pressure-affected areas refer to those spatially adjacent to a given pressure-affected area.

[0048] The characteristics of local pressure change include: when the pressure detection value corresponding to the local pressure area exceeds the preset normal pressure distribution range and is higher than the pressure detection value corresponding to the adjacent pressure area, the load is concentrated and transferred to the local pressure area.

[0049] The preset normal pressure distribution range is determined based on the pressure distribution of the corresponding pressure area and adjacent pressure areas under the initial steady state. During subsequent testing, the pressure readings of each local pressure area are compared with the preset normal pressure distribution range. When the pressure reading of a certain local pressure area exceeds the preset normal pressure distribution range and is higher than the pressure readings of adjacent pressure areas, it is determined that the load is concentrated and transferred to that local pressure area.

[0050] S3: Based on the characteristics of changes in the effective pressure-bearing area, the characteristics of changes in the pressure application location, and the characteristics of local pressure changes, identify the load-bearing state of the segment joints, and output corresponding early warning information based on the identified load-bearing state. The load-bearing state includes the effective contact area change state, the bias pressure state, the pressure concentration state, and the pressure distribution stability state. The identification rules for each load-bearing state are as follows.

[0051] Specifically, when at least one of the number, distribution range, and area of ​​the effective pressure-bearing area changes, it is determined that the area in which the segment joint actually participates in load transfer has changed, and this is identified as a change in the effective contact area.

[0052] When the position of the center of pressure application relative to the stress center of the segment joint changes, it is determined that the load transfer area of ​​the segment joint has shifted, and it is identified as an eccentric pressure state.

[0053] When the pressure detection value of the local pressure area increases beyond the preset normal pressure distribution range relative to the adjacent pressure area, it is determined that the load is concentrated in the local pressure area and identified as a pressure concentration state.

[0054] When the effective pressure-bearing area, the center of pressure action, and the local pressure distribution remain unchanged during continuous testing, it is identified as a stable pressure distribution state.

[0055] When the same detection state has multiple pressure spatial distribution characteristics, the identified load-bearing state includes the state corresponding to each pressure spatial distribution characteristic. For example, when the effective pressure-bearing area decreases, the position of the pressure center shifts, and the pressure detection value of the local pressure area suddenly increases under the same detection state, the identified load-bearing state simultaneously includes the effective contact area change state, the bias state, and the pressure concentration state.

[0056] After identifying the load-bearing status of the segment joint, the system outputs corresponding warning information based on the identified load-bearing status. Different load-bearing statuses correspond to different warning information to indicate the current load-bearing status of the segment joint.

[0057] Through the above steps S1 to S3, the effective pressure-bearing area that actually participates in load transfer is determined based on the spatial distribution characteristics of the pressure at the segment joint. Based on the changes in the effective pressure-bearing area, the changes in the pressure application location, and the local pressure changes, the changes in the effective contact area of ​​the segment joint, the bias pressure state, the pressure concentration state, and the stable pressure distribution state are identified, and corresponding early warning information is output based on the identification results.

[0058] Example 2 This embodiment is used to supplement the explanation of the process of determining the bearing state of the segment joint based on the pressure spatial distribution characteristics in Embodiment 1 when the load state of the segment joint changes. It should be noted that the process of determining the pressure detection location, pressure application area, effective pressure-bearing area, and pressure application center in Embodiment 1 is also applicable in this embodiment, and will not be repeated here.

[0059] I. Identification of Changes in Effective Contact Area Under the initial steady state, the effective pressure bearing capacity determination results of each pressure application area are recorded to form the initial effective pressure bearing capacity distribution. When the external load changes, the pressure detection values ​​at each pressure detection location within the segment joint contact surface are re-acquired, and the effective pressure bearing capacity is re-determined according to the method described in step S201 of Example 1.

[0060] When a portion of the pressure-bearing area within the original effective pressure-bearing zone no longer meets the effective pressure-bearing condition, that portion of the pressure-bearing area exits the effective pressure-bearing zone. By comparing the number, distribution range, and area of ​​the effective pressure-bearing zone under different testing conditions, the changes in the area of ​​the segment joint actually involved in load transfer are determined. When at least one of the number, distribution range, or area of ​​the effective pressure-bearing zone changes, it is determined that the area of ​​the segment joint actually involved in load transfer has changed, and this is identified as a change in the effective contact area.

[0061] II. Bias State Identification The bias state is determined based on the change in position of the pressure center relative to the stress center of the segment joint. In the initial stable state, the positional relationship between the pressure center and the stress center of the segment joint is recorded. After a change in external load, the pressure center is re-determined according to the method described in step S202 of Example 1, and the positional relationship between the pressure center and the stress center of the segment joint in subsequent detection states is compared with the positional relationship recorded in the initial stable state. When the position of the pressure center relative to the stress center of the segment joint changes, it is determined that the load transfer area of ​​the segment joint has shifted, and this is identified as a bias state; when the position of the pressure center relative to the stress center of the segment joint remains unchanged, it is not identified as a bias state.

[0062] III. Identification of Pressure Concentration State Based on the pressure change relationship between different pressure-affected areas, local pressure change characteristics are determined. In this embodiment, the pressure distribution of the pressure-affected area at the initial steady state and adjacent pressure-affected areas is defined as the preset normal pressure distribution range. During subsequent detection, the pressure detection values ​​corresponding to each local pressure-affected area are compared with the preset normal pressure distribution range. When the pressure detection value corresponding to a certain local pressure-affected area exceeds the preset normal pressure distribution range and is higher than the pressure detection values ​​corresponding to adjacent pressure-affected areas, it is determined that the load is concentrated and transferred to that local pressure-affected area, and this is identified as a pressure concentration state.

[0063] IV. Identification of Stable Pressure Distribution During the continuous testing phase with constant external load, the effective pressure-bearing area, pressure center, and local pressure distribution are compared sequentially at adjacent testing times. When the effective pressure-bearing area, pressure center, and local pressure distribution remain unchanged at adjacent testing times, the pressure spatial distribution at the segment joint is determined to be stable, and this is identified as a stable pressure distribution state.

[0064] In this embodiment, the four load-bearing states are determined based on their corresponding pressure spatial distribution characteristics. When the same detection state has multiple pressure spatial distribution characteristics, the identified load-bearing states include those corresponding to each pressure spatial distribution characteristic.

[0065] Through this embodiment, when the external load on the segment joint changes, the bearing state of the segment joint can be identified from three dimensions: changes in the effective pressure-bearing area, changes in the pressure application location, and changes in local pressure. This allows for timely understanding of changes in the actual load transfer area of ​​the segment joint, the offset of the load transfer area, and the local concentrated transfer of load.

[0066] Example 3 This embodiment uses the monitoring and early warning process of the circumferential joint of a shield tunnel segment as an example to illustrate the specific implementation process of the method described in Embodiment 1. The process of determining the pressure detection location, pressure application area, effective pressure-bearing area, and pressure application center in Embodiment 1 is also applicable in this embodiment and will not be repeated here.

[0067] I. Setting up the detection area and pressure detection location Reference Figure 2 A circumferential joint of a shield tunnel segment was selected as the inspection target. An inspection area with a length of 300 mm and a width of 200 mm was set within the contact surface of the segment joint. Based on the spatial coordinates of each pressure inspection location, the inspection area was spatially divided into 24 pressure action zones (6 columns × 4 rows), each measuring 50 mm × 50 mm with an area of ​​2500 mm².

[0068] The coordinate system is set with the lower left corner of the detection area as the origin, the joint length direction as the positive x-axis, and the joint width direction as the positive y-axis. The x-coordinates of the centers of the pressure application areas in each column are 25 mm, 75 mm, 125 mm, 175 mm, 225 mm, and 275 mm, respectively; the y-coordinates of the centers of the pressure application areas in each row are 25 mm, 75 mm, 125 mm, and 175 mm, respectively, from bottom to top. Each pressure detection position is set at the center of the corresponding pressure application area.

[0069] Reference Figure 3 The pressure readings are arranged from top to bottom in rows 1 to 4, and within each row, they are arranged in columns 1 to 6. Therefore, the vertical coordinates of the pressure application areas in rows 1, 2, 3, and 4 are 175 mm, 125 mm, 75 mm, and 25 mm, respectively.

[0070] The stress center of the segment joint is designed to be the stress center of the segment joint. In this embodiment, the geometric center of the detection area is taken as the stress center of the segment joint, and the coordinates of the geometric center are (150 mm, 100 mm).

[0071] II. Determination of the Effective Pressure-Bearing Region under Initial Steady State Based on the design pressure bearing value of the segment joint, the preset pressure bearing judgment value is determined to be 8.0 MPa.

[0072] Under the initial steady-state condition, the pressure readings at the 24 pressure detection locations are as follows: Row 1: 8.2 MPa, 8.5 MPa, 8.7 MPa, 7.9 MPa, 8.4 MPa, 8.6 MPa; Row 2: 8.8 MPa, 7.5 MPa, 8.1 MPa, 8.3 MPa, 8.6 MPa, 8.0 MPa; Row 3: 7.8 MPa, 8.4 MPa, 8.5 MPa, 7.6 MPa, 6.2 MPa, 6.5 MPa; Row 4: 6.8 MPa, 6.4 MPa, 6.0 MPa, 6.3 MPa, 6.1 MPa, 6.5 MPa.

[0073] By comparing each pressure detection value with the preset pressure judgment value of 8.0 MPa, a total of 12 pressure action areas with an effective pressure judgment parameter of 1 are obtained, namely the first row and first column, the second column, the third column, the fifth column and the sixth column, the second row and the first column, the third column, the fourth column, the fifth column and the sixth column, and the third row and the second column and the third column.

[0074] Substituting the effective pressure-bearing parameters of the 12 effective pressure-bearing zones and the area of ​​a single pressure-acting zone of 2500 mm² into the formula for calculating the area of ​​the effective pressure-bearing zone, we obtain that the area of ​​the effective pressure-bearing zone under the initial steady state is 30000 mm².

[0075] III. Determination of the center of pressure application under initial steady-state conditions Substituting the 24 pressure detection values ​​under the initial steady state, the area of ​​each pressure action region of 2500 mm², and the corresponding center coordinates of the pressure action region into the pressure action center calculation formula, the coordinates of the pressure action center under the initial steady state are obtained as (147.85 mm, 105.60 mm).

[0076] Record the positional relationship between the pressure center (147.85 mm, 105.60 mm) and the stress center (150 mm, 100 mm) of the segment joint under the initial steady state, as a benchmark for subsequent test state comparison.

[0077] IV. Identification of Changes in Effective Contact Area under Load Variation After changing the external load condition of the segment joints, pressure tests were performed again on the same testing area. Under the changed load condition, the pressure test values ​​at the 24 pressure testing locations were as follows: Row 1: 7.6 MPa, 7.8 MPa, 8.1 MPa, 8.3 MPa, 8.5 MPa, 8.7 MPa; Row 2: 7.2 MPa, 7.5 MPa, 7.8 MPa, 8.0 MPa, 8.4 MPa, 9.2 MPa; Row 3: 6.8 MPa, 7.0 MPa, 7.3 MPa, 7.6 MPa, 7.9 MPa, 8.2 MPa; Row 4: 6.2 MPa, 6.4 MPa, 6.6 MPa, 6.8 MPa, 7.0 MPa, 7.2 MPa.

[0078] Each pressure detection value is compared with the preset pressure judgment value of 8.0 MPa to obtain a total of 8 pressure action areas with an effective pressure judgment parameter of 1, namely the 3rd, 4th, 5th and 6th columns of the 1st row, the 4th, 5th and 6th columns of the 2nd row, and the 6th column of the 3rd row.

[0079] Substituting the effective pressure-bearing determination parameters of the eight effective pressure-bearing zones and the area of ​​a single pressure-acting zone of 2500 mm² into the formula for calculating the area of ​​the effective pressure-bearing zone, the area of ​​the effective pressure-bearing zone under the load change state is obtained as 20000 mm².

[0080] Compared to the initial stable state, the number of effective pressure-bearing zones decreased from 12 to 8, and the area of ​​the effective pressure-bearing zones decreased from 30,000 mm² to 20,000 mm², a reduction of 10,000 mm². Furthermore, the effective pressure-bearing zones concentrated on the right side of the detection area. This indicates a change in the area of ​​the segment joints actually involved in load transfer, identified as a change in the effective contact area.

[0081] V. Identification of Eccentric Pressure State under Load Variation Substituting the 24 pressure detection values ​​under load variation, the area of ​​each pressure action zone (2500 mm²), and the corresponding center coordinates of the pressure action zone into the pressure action center calculation formula, the coordinates of the pressure action center under load variation are obtained as (155.18 mm, 104.08 mm).

[0082] Compared to the initial steady state, the x-coordinate of the pressure center changed from 147.85 mm to 155.18 mm, shifting 7.33 mm in the positive x-axis direction; the y-coordinate changed from 105.60 mm to 104.08 mm, shifting 1.52 mm in the negative y-axis direction. This change in the positional relationship between the pressure center and the stress center of the segment joint indicates that the load transfer area of ​​the segment joint has shifted to the right of the detection area, identifying it as a biased pressure state.

[0083] VI. Identification of Pressure Concentration State In this embodiment, the pressure distribution of the pressure-affected area at the corresponding position in the initial stable state and the pressure distribution of the adjacent pressure-affected areas are determined as the preset normal pressure distribution range.

[0084] Under varying load conditions, the pressure reading in the pressure area of ​​row 2, column 6 is 9.2 MPa. The pressure reading in the pressure area above it (row 1, column 6) is 8.7 MPa, the pressure reading in the pressure area to the left (row 2, column 5) is 8.4 MPa, and the pressure reading in the pressure area below it (row 3, column 6) is 8.2 MPa. The pressure reading in the pressure area of ​​row 2, column 6 is higher than the pressure readings of the adjacent pressure areas and exceeds the preset normal pressure distribution range. Therefore, it is determined that the load is concentrated in the pressure area of ​​row 2, column 6, and this is identified as a pressure concentration state.

[0085] VII. Identification of Stable Pressure Distribution After load adjustment, the external load was kept constant, and continuous testing continued. During subsequent continuous testing phases, the effective pressure-bearing area at adjacent testing times remained within the aforementioned eight pressure-affected areas, with the pressure center consistently between 155.18 mm and 104.08 mm. The pressure readings for each pressure-affected area remained unchanged. Based on the consistent effective pressure-bearing area, pressure center, and local pressure distribution during continuous testing, the pressure distribution was identified as stable.

[0086] In this embodiment, by utilizing the spatial correspondence between pressure detection locations and pressure application areas, discretely acquired pressure detection values ​​are mapped to the contact surface of the segment joint to form a pressure spatial distribution. Based on the characteristics of changes in the effective pressure-bearing area, the characteristics of changes in the pressure application location, and the characteristics of local pressure changes, the system identifies the changing state, bias state, pressure concentration state, and stable pressure distribution state of the effective contact area of ​​the segment joint, and then outputs corresponding early warning information.

[0087] Example 4 In one embodiment, a shield tunnel segment monitoring and early warning device is provided to implement the shield tunnel segment monitoring and early warning method described in Embodiment 1. The device includes a pressure detection module, a pressure distribution construction module, a status recognition module, and an early warning module.

[0088] I. Pressure Detection Module The pressure detection module is located inside the contact surface of the segment joint to obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint and send the pressure detection values ​​to the pressure distribution construction module.

[0089] In one embodiment, the pressure detection module includes a pressure detection device and a data acquisition device. The pressure detection device is positioned at various pressure detection locations within the contact surface of the segment joint to detect the contact pressure generated during the contact process between adjacent segments. In this embodiment, the pressure detection device is a thin-film pressure sensor, installed at the corresponding pressure detection location. The pressure-sensing surface of the thin-film pressure sensor is in contact with the contact surface of the segment joint, so that the contact pressure generated between adjacent segments after assembly can act on the thin-film pressure sensor. The data acquisition device is connected to the pressure detection device and is used to collect the pressure detection values ​​at each pressure detection location and simultaneously record the spatial coordinates of each pressure detection location within the contact surface of the segment joint. The pressure detection module sends the pressure detection values ​​and corresponding spatial coordinates to the pressure distribution construction module.

[0090] II. Pressure Distribution Construction Module The pressure distribution construction module is connected to the pressure detection module. It is used to determine the characteristics of the effective pressure-bearing area, the characteristics of the pressure application location, and the characteristics of the local pressure change based on the spatial distribution of each pressure detection value on the contact surface of the segment joint under different detection conditions. The characteristics of the effective pressure-bearing area, the characteristics of the pressure application location, and the characteristics of the local pressure change are then sent to the status recognition module.

[0091] Specifically, the pressure distribution construction module divides the contact surface of the segment joint into spatial regions based on the spatial coordinates of each pressure detection location. The contact area within the range corresponding to each pressure detection location is determined as the pressure action area, with each pressure detection location corresponding to a pressure action area. The pressure detection value at each pressure detection location is then mapped to the corresponding pressure action area, forming a spatial distribution of each pressure detection value on the contact surface of the segment joint.

[0092] The pressure distribution construction module determines the effective pressure-bearing judgment parameter for each pressure-bearing area based on the pressure detection value and the preset pressure-bearing judgment value. Pressure-bearing areas with an effective pressure-bearing judgment parameter of 1 are defined as effective pressure-bearing areas. Furthermore, the module determines the variation characteristics of effective pressure-bearing areas based on the changes in the number, distribution range, and area of ​​effective pressure-bearing areas under different detection states. The area of ​​the effective pressure-bearing area is the sum of the products of each effective pressure-bearing judgment parameter and the area of ​​the corresponding pressure-bearing area. For the specific determination process, please refer to step S201 in Example 1.

[0093] The pressure distribution construction module calculates the center coordinates of each pressure-affected area based on the pressure detection value, area, and center coordinates of each pressure-affected area, using the product of the pressure detection value and area as the weight. This yields the pressure center. Furthermore, the module determines the pressure position change characteristics based on the positional relationship between the pressure center and the stress center of the segment joint under different detection conditions. For the specific determination process, please refer to step S202 in Example 1.

[0094] The pressure distribution construction module determines the local pressure change characteristics based on the comparison between the pressure detection value corresponding to each pressure action area and the pressure detection value corresponding to the adjacent pressure action area. For the specific determination process, please refer to step S203 in Example 1.

[0095] III. Status Recognition Module The status identification module is connected to the pressure distribution construction module. It identifies the load-bearing status of the segment joints based on the characteristics of changes in the effective pressure-bearing area, the characteristics of changes in the pressure application location, and the characteristics of local pressure changes. The identified load-bearing status is then sent to the early warning module. The load-bearing status includes the effective contact area change status, the bias pressure status, the pressure concentration status, and the pressure distribution stability status. The identification rules for each load-bearing status are the same as those described in step S3 of Example 1, and will not be repeated here.

[0096] IV. Early Warning Module The early warning module is connected to the status recognition module and is used to output corresponding early warning information based on the received load-bearing status. Different load-bearing statuses correspond to different early warning information to indicate the current load-bearing status of the segment joints.

[0097] The shield tunnel segment monitoring and early warning device provided in this embodiment can identify the actual load transfer area of ​​the segment joint and its load-bearing status changes, and output corresponding early warning information based on the identification results.

[0098] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for monitoring and early warning of shield tunnel segments, characterized in that, include: Obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint; Based on the spatial distribution of the pressure detection values ​​under different detection states on the contact surface of the segment joint, the characteristics of the effective pressure-bearing area variation, the characteristics of the pressure application location variation, and the characteristics of the local pressure variation are determined; wherein, the effective pressure-bearing area is the pressure application area where the pressure detection values ​​meet the preset pressure-bearing conditions, and the pressure application location is determined by the pressure application center; Based on the characteristics of the effective pressure-bearing area change, the characteristics of the pressure application location change, and the characteristics of the local pressure change, the bearing state of the segment joint is identified, and corresponding early warning information is output according to the identified bearing state; wherein, the bearing state includes the effective contact area change state, the bias state, the pressure concentration state, and the pressure distribution stable state.

2. The method for monitoring and early warning of shield tunnel segments according to claim 1, characterized in that, The step of obtaining pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint includes: Based on the range of the contact area of ​​the segment joint, multiple pressure detection positions are set within the contact surface of the segment joint. Before assembling the tunnel segments, pressure detection devices are installed at each of the pressure detection positions, and the pressure-sensing surface of the pressure detection device is in contact with the joint surface of the tunnel segment. During the contact process between adjacent segments after segment assembly, the contact pressure at each pressure detection position is collected by the pressure detection device to obtain the pressure detection value at each pressure detection position, and the spatial coordinates of each pressure detection position within the contact surface of the segment joint are recorded simultaneously.

3. The method for monitoring and early warning of shield tunnel segments according to claim 2, characterized in that, The pressure detection device is a thin-film pressure sensor.

4. The method for monitoring and early warning of shield tunnel segments according to claim 2, characterized in that, In the step of determining the effective pressure-bearing area variation characteristics, pressure application location variation characteristics, and local pressure variation characteristics based on the spatial distribution of each pressure detection value on the contact surface of the segment joint under different detection states, the method for determining the effective pressure-bearing area variation characteristics includes: Based on the spatial coordinates of each pressure detection position, the contact surface of the segment joint is spatially divided, and the contact area within the range corresponding to each pressure detection position is determined as the pressure action area, with each pressure detection position corresponding to a pressure action area. The pressure detection values ​​at each pressure detection location are mapped to the corresponding pressure application area, and the effective pressure-bearing determination parameter for each pressure application area is determined based on the pressure detection value corresponding to each pressure application area and the preset pressure-bearing determination value. When the pressure detection value corresponding to the pressure application area is not less than the preset pressure-bearing determination value, the effective pressure-bearing determination parameter is 1; when the pressure detection value corresponding to the pressure application area is less than the preset pressure-bearing determination value, the effective pressure-bearing determination parameter is 0. The pressure-bearing area where the effective pressure-bearing determination parameter is 1 is defined as the effective pressure-bearing area. Based on the changes in the distribution range and area under different detection states, the variation characteristics of the effective pressure-bearing area are determined.

5. The method for monitoring and early warning of shield tunnel segments according to claim 4, characterized in that, The preset pressure-bearing judgment value is determined based on the structural parameters of the segment joint, the design bearing requirements, and the stress conditions; the area of ​​the effective pressure-bearing region is the sum of the products of each of the effective pressure-bearing judgment parameters and the area of ​​the corresponding pressure-acting region.

6. The method for monitoring and early warning of shield tunnel segments according to claim 4, characterized in that, In the step of determining the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation based on the spatial distribution of each pressure detection value under different detection states on the contact surface of the segment joint, the method for determining the characteristics of pressure application location variation includes: Based on the pressure detection value, area, and center coordinates of each pressure-affected area, the center coordinates of each pressure-affected area are weighted using the product of the pressure detection value and area as the weight to obtain the pressure center. Record the positional relationship between the pressure center and the stress center of the segment joint under the initial stable state, and compare the positional relationship between the pressure center and the stress center of the segment joint under the subsequent detection state with the positional relationship recorded under the initial stable state. Determine the pressure position change characteristics based on the comparison results.

7. The shield tunnel segment monitoring and early warning method according to claim 4, characterized in that, In the step of determining the characteristics of effective pressure-bearing area variation, pressure application location variation, and local pressure variation based on the spatial distribution of each pressure detection value on the contact surface of the segment joint under different detection states, the method for determining the local pressure variation characteristics includes: Based on the comparison between the pressure detection values ​​corresponding to each pressure application area and the pressure detection values ​​corresponding to adjacent pressure application areas, local pressure change characteristics are determined; the local pressure change characteristics include: when the pressure detection value corresponding to the local pressure application area exceeds the preset normal pressure distribution range and is higher than the pressure detection value corresponding to the adjacent pressure application area, the load is concentrated and transferred to the local pressure application area.

8. The method for monitoring and early warning of shield tunnel segments according to claim 7, characterized in that, The preset normal pressure distribution range is determined based on the pressure action area at the corresponding position under the initial stable state and the pressure distribution of the adjacent pressure action areas.

9. The method for monitoring and early warning of shield tunnel segments according to claim 4, characterized in that, The step of identifying the bearing state of the segment joint based on the variation characteristics of the effective pressure-bearing area, the variation characteristics of the pressure application location, and the local pressure variation characteristics includes: When at least one of the number, distribution range and area of ​​the effective pressure-bearing area changes, it is determined that the area of ​​the segment joint that actually participates in load transfer has changed, and this is identified as a change in the effective contact area. When the position of the pressure center relative to the stress center of the segment joint changes, it is determined that the load transfer area of ​​the segment joint has shifted, and this is identified as the bias state. When the pressure detection value corresponding to the local pressure area increases beyond the preset normal pressure distribution range relative to the adjacent pressure area, it is determined that the load is concentrated and transferred to the local pressure area, and it is identified as the pressure concentration state. When the effective pressure-bearing area, the pressure center, and the local pressure distribution remain unchanged during continuous detection, it is identified as a stable pressure distribution state. When the same detection state has multiple pressure spatial distribution features, the identified load state includes the state corresponding to each of the pressure spatial distribution features.

10. A shield tunnel segment monitoring and early warning device, characterized in that, It includes a pressure detection module, a pressure distribution construction module, a status recognition module, and an early warning module; The pressure detection module is located inside the contact surface of the segment joint and is used to obtain pressure detection values ​​at multiple pressure detection locations within the contact surface of the segment joint and send the pressure detection values ​​to the pressure distribution construction module. The pressure distribution construction module is connected to the pressure detection module and is used to determine the effective pressure-bearing area change characteristics, pressure application location change characteristics, and local pressure change characteristics based on the spatial distribution of each pressure detection value on the contact surface of the segment joint under different detection states. The effective pressure-bearing area change characteristics, pressure application location change characteristics, and local pressure change characteristics are then sent to the state recognition module. The effective pressure-bearing area is the pressure application area where the pressure detection value meets the preset pressure-bearing conditions, and the pressure application location is determined by the pressure application center. The state recognition module is connected to the pressure distribution construction module and is used to identify the bearing state of the segment joint based on the effective pressure bearing area change characteristics, the pressure application location change characteristics, and the local pressure change characteristics, and send the identified bearing state to the early warning module; the bearing state includes the effective contact area change state, the bias state, the pressure concentration state, and the pressure distribution stable state; The early warning module is connected to the status recognition module and is used to output corresponding early warning information based on the received bearer status.

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