Digital splicing method for shield tunnel segments

Abstract

The invention discloses a shield tunnel segment digital splicing method, which comprises the following steps: step 1, generating segment point cloud data: performing reverse scanning on a single segment through a laser scanning system in a shield tunneling machine until the scanning of the whole-ring segment of a tunnel is completed, and generating the segment point cloud data; step 2, obtaining an optimal relative position between segments: importing the segment point cloud data into a virtual assembling platform, establishing a segment three-dimensional model, planning a segment assembling path in the virtual assembling platform, and then performing segment virtual assembling according to the segment assembling path to obtain the optimal relative position between the segments; 3, calculating a theoretical rotation angle: calculating the theoretical rotation angle of the central line of the segment relative to the vertical center of the circle center when the segment is at the optimal relative position; step 4, calculating a position deviation and an offset angle; and sixthly, the pipe pieces are assembled. According to the method, a complete and efficient digital splicing system is established, and the overall level of shield tunnel construction is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel construction, and particularly to a digital assembly method for shield tunnel segments. Background Art

[0002] In the field of shield tunnel construction, segment assembly is a crucial link. Traditional segment assembly methods mainly rely on manual operation, which has many drawbacks. For example, in terms of assembly accuracy, due to the lack of precise detection means, it is difficult for operators to accurately control the assembly dimensions of segments. Often, problems with segment dimensions are only noticed when the assembly goes smoothly, resulting in low assembly accuracy. In terms of assembly efficiency, manually adjusting the position of segments is time-consuming and laborious, seriously affecting the construction efficiency. In terms of assembly quality, the instability of manual operation makes the assembly quality of segments uneven, and it is difficult to ensure the stability and durability of the entire tunnel structure.

[0003] With the rapid development of technology, digital technology is increasingly widely used in tunnel construction, providing an opportunity to solve the defects of traditional segment assembly methods. Currently, the technical solutions relatively close to the present application that have been publicly disclosed mostly focus on partial digital assistance, such as only using simple positioning sensors during segment transportation, or performing rough digital records of quality inspection after assembly, but have not formed a digital system covering the whole process from segment measurement, virtual assembly calculation to precise control of assembly.

[0004] Therefore, it is extremely urgent to develop a digital assembly method for shield tunnel segments in the tunnel, which will have extremely important practical significance and broad application value for aspects such as improving the quality, efficiency, and cost control of tunnel construction. Summary of the Invention

[0005] The purpose of the present invention is to provide a digital assembly method for shield tunnel segments, which solves many drawbacks in segment assembly, establishes a complete and efficient digital assembly system, and improves the overall level of shield tunnel construction.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A digital assembly method for shield tunnel segments includes the following steps: Step 1: Generate segment point cloud data: Through the internal laser scanning system of the shield machine, perform reverse scanning on a single segment until the scanning of the entire ring of segments in the tunnel is completed, generating segment point cloud data; Step 2: Obtain the optimal relative position between segments: Import the segment point cloud data into the virtual assembly platform, establish a 3D model of the segments, plan the segment assembly path within the virtual assembly platform, and then perform virtual assembly of the segments according to the segment assembly path to obtain the optimal relative position between the segments; Step 3. Calculate the theoretical rotation angle: When the segment is at the optimal relative position, calculate the theoretical rotation angle of the center line of the segment relative to the vertical center of the circle center. Step 4. Calculate the position deviation and offset angle: Install sensors on the segment to be assembled, then transport the segment with sensors installed to the segment assembly equipment of the shield machine. Measure the specific position of the segment to be assembled on the vacuum chuck of the segment assembly equipment of the shield machine through the sensors, and thus calculate the position deviation and offset angle. Step 5. Unify the origin: First, precisely calibrate the segment assembly equipment of the shield machine, and then make the center of the vacuum chuck coincide with the center coordinates of the virtual assembly platform in the three-dimensional space. Step 6. Assemble the segments: The segment assembly equipment of the shield machine controls the movement of the vacuum chuck according to the offset angle, position deviation, and theoretical rotation angle of each segment, monitors and feeds back the segments in real time through the sensors, and adjusts the error in a timely manner.

[0007] Preferably, the laser scanning system includes a laser, a detector, and a data processing unit. The laser beam emitted by the laser irradiates the surface of the segment and is received by the detector after being reflected on the surface of the segment. The detector converts the reflected light signal into an electrical signal and transmits it to the data processing unit. The data processing unit calculates the three-dimensional coordinates of each point on the surface of the segment through the triangulation algorithm based on the time difference between the emission time of the laser beam in the laser and the reception time of the reflected light in the detector, as well as the propagation speed of the laser beam, so as to generate the point cloud data of the segment.

[0008] Preferably, the specific content of Step 2 is: After scanning the entire ring of segments in the tunnel through the internal laser scanning system of the shield machine, import the point cloud data of the segments into the virtual assembly platform, analyze and process the point cloud data of the segments through the virtual assembly platform, establish a three-dimensional model of the segments, plan the segment assembly path in the virtual assembly platform, construct a global coordinate system, define and extract the key specific features of the segment assembly, and then perform virtual assembly of the segments according to the segment assembly path, and continuously optimize the pose of the segments to obtain the optimal relative position.

[0009] Preferably, the processing of the point cloud data of the segments includes denoising, filtering, and segmentation of the point cloud data of the segments.

[0010] Preferably, the optimization of the pose of the segments is specifically as follows: S1. First, perform initial alignment of the obvious feature points and the center of the segment between the three-dimensional model of the segment and the design model of the tunnel segment to obtain the initial pose. S2. Collect a certain number of points in the three-dimensional model of the segment, and then find the corresponding points on the design model of the tunnel segment to form a set of point pairs. S3. According to the distance between the points and the corresponding points, calculate the overall error between the three-dimensional model of the segment and the design model of the tunnel segment in the initial pose by using the measurement method of the root mean square error. S4. Determine the pose adjustment amount that reduces the overall error by the least squares method, and use iterative optimization until the overall error converges to a minimum value or reaches the preset number of iterations to complete the registration of a single segment. S5. Repeat S4 until the optimal pose of each segment and the corresponding overall error are obtained. S6. Combine every ten segments according to the actual connection relationship and layout to establish a comprehensive segment model, and analyze the matching of the connection components of each segment in the initial pose, whether the edges of adjacent segments are aligned, and whether the curvature at the interface is continuous. S7. Continuously fine-tune the segments in the comprehensive segment model until the comprehensive segment error converges to a minimum value or reaches the preset number of iterations to complete the collaborative adjustment.

[0011] Preferably, in step four, the sensor includes a laser displacement sensor and an inclination sensor; the laser beam emitted by the laser displacement sensor irradiates the edge and surface of the segment, and the position deviation of the segment relative to the center of the vacuum chuck is calculated by measuring the reflection time and angle change of the laser beam; the inclination sensor is used to measure the inclination angle of the segment relative to the horizontal plane, and the offset angle of the segment is calculated through the inclination angle.

[0012] Preferably, step five is specifically: install a positioning sensor and a calibration device on the segment assembling equipment of the shield machine to measure the position coordinates of the center of the vacuum chuck, match and unify the measured position coordinates of the center of the vacuum chuck with the center coordinates of the virtual device, then use a rangefinder to measure the three-dimensional coordinates at the center of the vacuum chuck, input the three-dimensional coordinates at the center of the vacuum chuck into the control system, and adjust the mechanical structure and motion parameters of the segment assembling equipment of the shield machine through the control system to achieve the coincidence of the center coordinates of the vacuum chuck and the virtual device in three-dimensional space.

[0013] Preferably, the segment assembling equipment of the shield machine uses an assembling actuator to assemble segments. The assembling actuator includes a motor, a reducer, a transmission component, and a vacuum chuck. The motor rotates in the direction and at the speed set according to the instructions of the control system. A transmission component is connected to the power output end of the motor through a reducer, and the vacuum chuck is installed on the transmission component and driven by the transmission component to move.

[0014] In the present invention, the segment is scanned comprehensively and with high precision by a laser scanning system to accurately obtain characteristic data such as the dimensions of the key assembling positions of the segment, providing basic data support for subsequent precise assembling.

[0015] Use a virtual assembling platform to process and analyze the point cloud data of the scanned segment, simulate the segment assembling process, calculate the optimal relative positions and accurate pose information between each segment block, and effectively reduce the errors and uncertainties in actual assembling.

[0016] Based on the precise posture calculation results obtained from virtual assembly, an intelligent precise assembly control system is constructed to achieve precise control of the shield machine assembly equipment, ensuring that the segments can complete the assembly work according to the predetermined high-precision requirements during the actual assembly process.

[0017] Through the digital assembly method within the shield tunnel segments, precise measurement of the segments before assembly is achieved, and the dimensions of key assembly positions are extracted. Then, by simulating the assembly on a virtual assembly platform, the optimal relative positions between the optimal segments are output.

[0018] Compared with the existing technology, this assembly method forms a complete digital link, realizes digital measurement and digital assembly, and builds a full-process digital system from segment measurement, virtual assembly calculation to precise control assembly.

[0019] Through the measurement of laser scanning system and sensor, the accurate position and posture information of the segment can be obtained, thereby improving the accuracy of segment assembly. Experimental data show that after adopting this method, the position error of segment assembly can be controlled within sub-millimeter, while the error of traditional methods is usually above centimeter level.

[0020] The virtual assembly platform can calculate the optimal relative position between segments, further improving the accuracy of segment assembly. After virtual assembly optimization, the uniformity of the gaps between segments is improved, effectively reducing the problem of uneven structural force caused by uneven gaps.

[0021] The assembly actuator controls the vacuum suction cup to precisely adjust the posture to accurately adjust the pipe segment, which improves the assembly accuracy of the pipe segment. In actual applications, the angular accuracy of the vacuum suction cup's posture adjustment is further improved, ensuring that the pipe segment can be accurately assembled according to the predetermined position and angle.

[0022] The digital assembly method can realize automated operation, reduce manual intervention, and improve the efficiency of segment assembly. On-site construction data shows that after adopting the digital assembly method, the speed of segment assembly can be greatly improved, shortening the tunnel construction period.

[0023] Precise segment assembly can reduce gaps and misalignments between segments, improve the quality of segment assembly, and effectively enhance the safety and durability of the tunnel.

[0024] The assembly actuator controls the vacuum suction cup to precisely adjust the posture to avoid damage to the segments during the assembly process and ensure the quality of the segments. Due to the precise vacuum suction cup posture control, the collision and friction of the segments during the assembly process are reduced, reducing the risk of surface damage and internal cracks on the segments.

[0025] The present invention is mainly applied to the segment assembly link in shield tunnel construction, and can be widely applied to shield tunnel projects with various geological conditions and tunnel scales. It can effectively improve the quality, efficiency and safety of tunnel construction, reduce the construction cost and the later maintenance cost, and promote the digital and intelligent development of shield tunnel construction technology. Brief Description of the Drawings

[0026] Figure 1 It is a schematic flow chart of the present invention; Detailed Embodiments

[0027] The following further describes the present invention in conjunction with the drawings: As Figure 1 shown, a digital segment assembly method for shield tunnels includes the following steps: Step 1, generating segment point cloud data: Through the internal laser scanning system of the shield machine, a single segment is reversely scanned until the scanning of the entire ring of segments in the tunnel is completed, and segment point cloud data is generated.

[0028] The laser scanning system includes a laser, a detector and a data processing unit. The laser beam emitted by the laser irradiates the surface of the segment and is received by the detector after being reflected on the surface of the segment. The detector converts the reflected light signal into an electrical signal and transmits it to the data processing unit. The data processing unit calculates the three-dimensional coordinates of each point on the surface of the segment through the triangulation algorithm based on the time difference between the emission time of the laser beam in the laser and the reception time of the reflected light in the detector, as well as the propagation speed of the laser beam, thereby generating segment point cloud data.

[0029] The detector uses sensitive elements such as photomultiplier tubes or avalanche photodiodes, which can convert weak reflected laser signals into processable electrical signals. The data processing unit includes a high-performance central processing unit (CPU) and a graphics processing unit (GPU), as well as specially developed point cloud data processing software. When performing reverse scanning, first place the segment on a fixed and precisely calibrated scanning platform, and then start the laser scanning system. The laser emits laser beams according to preset scanning paths and parameters, such as the scanning angle range, scanning speed, scanning resolution, etc.

[0030] During the scanning process, the data processing unit will also perform real-time quality monitoring and preliminary processing on the collected point cloud data, such as removing abnormal points and noise points, to improve the quality and accuracy of the point cloud data.

[0031] Step 2, obtaining the optimal relative position between segments: Import the segment point cloud data into the virtual assembly platform, establish a three-dimensional model of the segment, plan the segment assembly path in the virtual assembly platform, and then perform virtual segment assembly according to the segment assembly path to obtain the optimal relative position between segments.

[0032] Specifically: After the internal laser scanning system of the shield machine completes the scanning of the entire ring of tunnel segments, the segment point cloud data is imported into the virtual assembly platform. The virtual assembly platform analyzes and processes the segment point cloud data, establishes a three-dimensional model of the segment, plans the segment assembly path within the virtual assembly platform, constructs a global coordinate system, defines and extracts the key specific features of segment assembly, and then performs virtual assembly of the segments according to the segment assembly path, continuously optimizing the segment pose to obtain the optimal relative position.

[0033] To construct the global coordinate system, it is necessary to first define the origin of the entire ring of segments, then form the global coordinate system with the coordinate axes of the entire ring of segments, define the coordinate systems of the associated single segments, and finally convert the coordinate systems of the associated single segments into the global coordinate system.

[0034] The processing of segment point cloud data includes denoising, filtering, and segmentation of the segment point cloud data to improve the quality and accuracy of the point cloud data. In one embodiment, the Gaussian filtering algorithm is used to remove the noise points in the point cloud data, and the region growing algorithm is used to segment the point cloud data of the segments from the point cloud data of the surrounding environment to extract the individual point cloud data of the segments.

[0035] Specifically, the optimization of the segment pose is as follows: S1. First, perform an initial alignment of the obvious feature points and the segment center between the three-dimensional model of the segment and the design model of the tunnel segment to obtain the initial pose. S2. Collect a certain number of points in the three-dimensional model of the segment, and then find the corresponding points on the design model of the tunnel segment to form a set of point pairs. S3. According to the distance between the points and the corresponding points, use the root mean square error measurement method to calculate the overall error between the three-dimensional model of the segment and the design model of the tunnel segment in the initial pose. S4. Determine the pose adjustment amount that reduces the overall error through the least squares method, and use iterative optimization until the overall error converges to a minimum value or reaches the preset number of iterations to complete the registration of a single segment. S5. Repeat S4 until the optimal pose of each segment and the corresponding overall error are obtained. S6. Combine every ten segments according to the actual connection relationship and layout to establish a comprehensive segment model, and analyze the matching situation of the connection components of each segment in the initial pose, whether the edges of adjacent segments are aligned, and whether the curvature at the interface is continuous. S7. Continuously fine-tune the segments in the comprehensive segment model until the comprehensive error of the segments converges to a minimum value or reaches the preset number of iterations to complete the collaborative adjustment.

[0036] The process of virtual segment assembly includes point cloud data processing, three-dimensional modeling, optimization algorithm calculation, and virtual assembly.

[0037] 3D modeling refers to establishing a 3D model of the segment based on the processed point cloud data. For the processing of a single segment: through point cloud noise reduction, outlier removal, point cloud filtering, and segmentation data preprocessing, a high-precision point cloud model is reconstructed based on the extracted features. A feature-based modeling method is adopted. For example, based on features such as the edge contour and hole shape of the segment, a 3D geometric model of the segment is constructed. The model is represented parametrically for subsequent modification and optimization.

[0038] Step 3: Calculate the theoretical rotation angle: When the segment is at the optimal relative position, calculate the theoretical rotation angle of the segment center line relative to the vertical center of the circle center. Step 4: Calculate the position deviation and offset angle: Install sensors on the segment to be assembled, and then transport the segment with sensors installed to the segment assembly equipment of the shield machine. Measure the specific position of the segment to be assembled on the vacuum chuck of the segment assembly equipment of the shield machine through the sensors. Use the built-in mathematical model and algorithm of the virtual assembly platform for the specific position data to calculate the position deviation and offset angle. The sensors include a laser displacement sensor and an inclination sensor; the laser beam emitted by the laser displacement sensor irradiates the edge and surface of the segment. By measuring the reflection time and angle change of the laser beam, the position deviation of the segment relative to the center of the vacuum chuck is calculated; the inclination sensor is used to measure the inclination angle of the segment relative to the horizontal plane, and the offset angle of the segment is calculated through the inclination angle. In one embodiment, if the laser displacement sensor detects that the segment deviates 5 mm (position deviation) from the center of the vacuum chuck in the X-axis direction and 3 mm (position deviation) from the center of the vacuum chuck in the Y-axis direction, and the inclination sensor detects that the segment tilts 3° clockwise in the plane (tilt angle), the control system will calculate the offset angle of the segment based on the position deviation and offset angle.

[0039] Step 5: Unify the origin: First, precisely calibrate the segment assembly equipment of the shield machine, and then make the center of the vacuum chuck coincide with the center coordinates of the virtual assembly platform in three-dimensional space. Specifically: Install a positioning sensor and a calibration device on the segment assembly equipment of the shield machine to measure the position coordinates of the center of the vacuum chuck. Match and unify the measured position coordinates of the center of the vacuum chuck with the center coordinates of the virtual device. Then use a rangefinder to measure the three-dimensional coordinates at the center of the vacuum chuck, and input the three-dimensional coordinates at the center of the vacuum chuck into the control system. Adjust the mechanical structure and motion parameters of the segment assembly equipment of the shield machine through the control system to achieve the coincidence of the center of the vacuum chuck and the center coordinates of the virtual device in three-dimensional space, so as to ensure the position accuracy and consistency of the segment during the assembly process.

[0040] Step 6: Assemble the segment: The segment assembly equipment of the shield machine controls the movement of the vacuum suction cup based on the offset angle, position deviation, and theoretical rotation angle of each segment, monitors and feeds back the segment in real time through sensors, and adjusts the error in a timely manner.

[0041] The segment assembly equipment of the shield machine uses the assembly actuator to assemble the segment. The assembly actuator includes a motor, a reducer, a transmission component, and a vacuum suction cup. The motor rotates in a set direction and speed under the command of the control system. A transmission component is connected to the power output end of the motor through a reducer. The vacuum suction cup is installed on the transmission component and is driven by the transmission component to move.

[0042] The above embodiments are only several explanations of the concept and implementation of the present invention, and do not limit it. Under the concept of the present invention, the technical solutions without substantial transformation are still within the protection scope.

Claims

1. A digital assembly method for shield tunnel segments, characterized in that It includes the following steps: Step 1, generating segment point cloud data: Through the internal laser scanning system of the shield machine, reverse scanning is performed on a single segment until the scanning of the entire ring of segments in the tunnel is completed, generating segment point cloud data; Step 2, obtaining the optimal relative position between segments: Import the segment point cloud data into the virtual assembly platform, establish a 3D model of the segments, plan the segment assembly path within the virtual assembly platform, and then perform virtual assembly of the segments according to the segment assembly path to obtain the optimal relative position between the segments; Step 3, calculating the theoretical rotation angle: When the segments are in the optimal relative position, calculate the theoretical rotation angle of the segment center line relative to the vertical center of the circle; Step 4, calculating the position deviation and offset angle: Install sensors on the segment to be assembled, and then transport the segment with sensors installed to the shield machine assembly equipment. Measure the specific position of the segment to be assembled on the vacuum chuck of the shield machine assembly equipment through the sensors, and thereby calculate the position deviation and offset angle; Step 5, unifying the origin: First, precisely calibrate the shield machine assembly equipment, and then make the center of the vacuum chuck coincide with the center coordinates of the virtual assembly platform in the three-dimensional space; Step 6, assembling the segments: The shield machine assembly equipment controls the movement of the vacuum chuck according to the offset angle, position deviation, and theoretical rotation angle of each segment, and conducts real-time monitoring and feedback on the segments through the sensors to adjust the error in a timely manner.

2. The digital assembly method of the segment for shield tunnel according to claim 1, wherein: The laser scanning system includes a laser, a detector, and a data processing unit. The laser beam emitted by the laser irradiates the surface of the segment and is received by the detector after being reflected on the surface of the segment. The detector converts the reflected light signal into an electrical signal and transmits it to the data processing unit. The data processing unit calculates the three-dimensional coordinates of each point on the surface of the segment through the triangulation algorithm based on the time difference between the emission time of the laser beam in the laser and the reception time of the reflected light in the detector, as well as the propagation speed of the laser beam, thereby generating segment point cloud data.

3. The digital assembly method of shield tunnel segments according to claim 1, characterized in that The specific content of Step 2 is: After completing the scanning of the entire ring of segments in the tunnel through the internal laser scanning system of the shield machine, import the segment point cloud data into the virtual assembly platform, analyze and process the segment point cloud data through the virtual assembly platform, establish a 3D model of the segments, plan the segment assembly path within the virtual assembly platform, construct a global coordinate system, define and extract the key specific features of segment assembly, and then perform virtual assembly of the segments according to the segment assembly path, continuously optimizing the pose of the segments to obtain the optimal relative position.

4. The digital assembly method of segment for shield tunnel according to claim 3, wherein: The processing of the segment point cloud data includes denoising, filtering, and segmentation of the segment point cloud data.

5. The digital assembly method of the shield tunnel segment according to claim 3 or 4, characterized in that, The specific content of optimizing the pose of the segments is: S1, first perform an initial alignment of the obvious feature points and the segment center between the 3D model of the segments and the tunnel segment design model to obtain the initial pose; S2, collect a certain number of points in the 3D model of the segments, and then find the corresponding points on the tunnel segment design model to form a set of point pairs; S3, according to the distance between the points and the corresponding points, calculate the overall error between the 3D model of the segments and the tunnel segment design model in the initial pose by using the measurement method of the root mean square error; S4. Determine the pose adjustment amount that reduces the overall error by the least squares method, and perform iterative optimization until the overall error converges to a minimum value or reaches the preset number of iterations to complete the registration of a single segment. S5. Repeat S4 until the optimal pose of each segment and the corresponding overall error are obtained. S6. Combine every ten segments according to the actual connection relationship and layout to establish a comprehensive segment model, and analyze the matching situation of the connection components of each segment in the initial pose, whether the edges of adjacent segments are aligned, and whether the curvature at the interface is continuous. S7. Continuously fine-tune the segments in the comprehensive segment model until the comprehensive error of the segments converges to a minimum value or reaches the preset number of iterations to complete the collaborative adjustment.

6. The digital assembly method of the shield tunnel segment according to claim 1, characterized in that: In the fourth step, the sensor includes a laser displacement sensor and an inclination sensor; the laser beam emitted by the laser displacement sensor irradiates the edge and surface of the segment, and the position deviation of the segment relative to the center of the vacuum chuck is calculated by measuring the reflection time and angle change of the laser beam; the inclination sensor is used to measure the inclination angle of the segment relative to the horizontal plane, and the offset angle of the segment is calculated through the inclination angle.

7. The digital assembly method of shield tunnel segments according to claim 1, characterized in that, The fifth step is specifically as follows: Install a positioning sensor and a calibration device on the segment assembling device of the shield machine to measure the position coordinates of the center of the vacuum chuck, match and unify the measured position coordinates of the center of the vacuum chuck with the center coordinates of the virtual device, then use a rangefinder to measure the three-dimensional coordinates at the center of the vacuum chuck, input the three-dimensional coordinates at the center of the vacuum chuck into the control system, and adjust the mechanical structure and motion parameters of the segment assembling device of the shield machine through the control system to achieve the coincidence of the center of the vacuum chuck and the center coordinates of the virtual device in three-dimensional space.

8. The digital assembly method of the segment for shield tunnel according to claim 1, wherein: The segment assembling device of the shield machine uses an assembling actuator to assemble segments. The assembling actuator includes a motor, a reducer, a transmission component, and a vacuum chuck. The motor rotates in the direction and at the speed set under the command of the control system. A transmission component is connected to the power output end of the motor through the reducer, and the vacuum chuck is installed on the transmission component and driven by the transmission component to move.

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