Tunnel multi-section construction monitoring and measuring method

Abstract

The invention belongs to the technical field of monitoring and measuring, and particularly relates to a tunnel multi-section construction monitoring and measuring method, which comprises the following steps of: establishing monitoring on the length of an axis of a tunnel through a three-dimensional model, extracting three-dimensional point cloud data in the length direction of the axis of the tunnel according to a preset monitoring distance of each section; and extracting an arc-shaped coordinate sequence of the section from the three-dimensional point cloud data of each section, and monitoring a convergence value and peripheral convergence according to the arc-shaped coordinate sequence of the tunnel and monitoring side lengths of three sides of a triangle formed by two points symmetrical about a Y axis and a Z axis on each section of the tunnel. Compared with a manual measurement mode, the range of sampled points is larger, more sample data are obtained, the data can better reflect the deformation quantity of the tunnel, the convergence value of the periphery of each section of the tunnel and calculation of the convergence value are achieved by calculating the length of three sides of a plurality of triangles in the section of the tunnel, and the deformation condition of the tunnel is reflected more accurately.

Description

Technical Field

[0001] The invention belongs to the technical field of monitoring and measurement, and in particular relates to a method for monitoring and measuring construction of multiple sections of a tunnel. Background Art

[0002] The multi-section construction monitoring and measurement of tunnels is to set up multiple monitoring and measurement sections with different mileages according to the tunnel surrounding rock grade and on-site construction plan during the tunnel construction process, and set up multiple monitoring points on each monitoring and measurement section. Various types of instruments and tools are used to monitor the deformation and stress state of the surrounding rock and supporting lining in sections, providing key data support for construction safety and quality control.

[0003] Among them, peripheral convergence and convergence value are key data reflecting tunnel deformation. Traditional measurement methods include using tools such as convergence meters or total stations, usually setting measurement points at specific locations on the tunnel section, and then evaluating the convergence of the tunnel by regularly measuring the distance changes between these points. Although this method can reflect the deformation trend of the tunnel to a certain extent, it is difficult to fully and accurately capture the complex deformation of the tunnel section due to its limited selection of measurement points and its main focus on the changes in the straight-line distance between the measurement points.

[0004] In fact, tunnels are affected by many factors during construction, such as geological conditions, construction technology, groundwater, etc. These factors can cause multi-directional and complex deformation of the tunnel section. For example, the tunnel section may have multiple deformation modes such as asymmetric convergence, distortion, and uplift. In this case, if we still rely on only a few measurement points to calculate the convergence value, it is difficult for the measurement data to accurately reflect the actual deformation of the tunnel section, which may lead to misjudgment or omission of safety hazards in the tunnel.

[0005] In this regard, adding measurement points on the cross-section of the tunnel can increase the sample capacity and make the measurement results closer to the actual tunnel deformation. However, due to the increase in the number of measurement points, not only is the measurement process time-consuming and labor-intensive, but there are also great challenges in data processing and analysis.

[0006] Therefore, it is necessary to improve the tunnel construction monitoring and measurement methods to improve the measurement accuracy and provide more accurate data support for tunnel construction. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a multi-section tunnel construction monitoring system to solve the problem that the deformation direction is diversified due to the complex geology of the tunnel surrounding rock, and the limited measurement points cannot accurately reflect the tunnel shape.

[0008] The purpose of the present invention can be achieved by the following technical solution: A tunnel multi-section construction monitoring and measurement method comprises the following steps:

[0009] Step 1: Set up multiple monitoring measurement sections with different mileages at a certain distance according to the tunnel surrounding rock grade and on-site construction plan;

[0010] Step 2: Obtain the three-dimensional point cloud data of the tunnel, scan the tunnel with a three-dimensional laser scanner, obtain the three-dimensional point cloud data of the tunnel, and perform denoising and filtering on the point cloud data;

[0011] Step 3: Obtain the arc coordinate sequence of each section of the tunnel, determine the tunnel axis, establish a three-dimensional coordinate system with the tunnel section height direction as the Y axis, the tunnel section width direction as the X axis, the tunnel axis direction as the Z axis, and the tunnel starting point as the zero point, cut each tunnel section at a certain distance in the point cloud data, and extract the arc position coordinate sequence of each section;

[0012] Step 4: Calculate the peripheral convergence value of each section of the tunnel, extract the coordinates of two points symmetrical about the Y axis from the arch arc position coordinate sequence of each section, calculate the three sides of the triangle formed by the two points and the two points and Z respectively to generate a triangle side length subsequence {a, b, c}, where a is the interval between the two points, b is the interval between one of the points and Z=0, and c is the interval between the other point and Z=0. The subsequent triangle side length subsequences of the symmetrical points about the Y axis form a section triangle side length sequence {{a1, b1, c1}, ..., {an, bn, cn}}, and the measurement of the peripheral convergence value of the tunnel is achieved through b and c;

[0013] Repeat steps 1 to 4, generate triangle side length sequences of each time interval t in each section respectively, and monitor the convergence of the perimeter of each section of the tunnel through the changes of b and c values;

[0014] Step 5: Calculate the convergence value of each section of the tunnel, extract t at interval t n+1 Time and t n The distance difference between two time-symmetric points is subtracted to generate a distance difference sequence, and step 5 is repeated to monitor the convergence value of each section of the tunnel;

[0015] The peripheral convergence value threshold and the convergence value threshold are determined according to the tunnel monitoring specification, and an automatic alarm is issued when the peripheral convergence value exceeds the peripheral convergence threshold or the convergence value exceeds the convergence value threshold.

[0016] Preferably, step 4 further comprises: n+1 Time and t nThe changes in the b and c values ​​at time generate the b change curve function and the c change curve function, and the change values ​​of b and c at the next time are predicted based on the fitting of the b change curve function and the c change curve function, and an early warning will be issued when they exceed the surrounding convergence value.

[0017] Preferably, the deformation amounts on both sides symmetrical about the Y axis in each section of the tunnel are analyzed by comparing the b change curve function and the c change curve function.

[0018] Preferably, step 5 further comprises generating a sequence of arc position coordinates of the arch surface of each section, generating t n Time and t n+1 The Y-axis difference sequence of time is used to generate a time-Y-axis difference function to predict the deformation of the vertical height of the tunnel, wherein the vault settlement is extracted from the Y-axis difference sequence at the zero point.

[0019] Preferably, in step 4, the following method is used to extract the coordinates of two points symmetrical about the Y axis from an arc coordinate sequence of a cross section:

[0020] A symmetry plane with the Y axis in a section as the symmetry axis:

[0021] a: First select the arch top, arch waist and arch foot;

[0022] b: Select the midpoint between two adjacent points among the three points to get the other two points;

[0023] c: Determine the number of cycles of step b according to the width of the tunnel, obtain the measurement points of a symmetric plane of the tunnel, and remove the overlapping points to obtain the horizontal coordinate set of the points {x1, ..., xn}, symmetric the elements in the point set about the Y axis, and obtain the horizontal coordinate set of two points symmetric about the Y axis in a section {{x1, xn} 1}, ..., {xn, x n}}, according to the extracted horizontal coordinate, the X-axis and Y-axis corresponding to the corresponding horizontal coordinate are extracted from the arch surface arc coordinate sequence.

[0024] Preferably, the X-axis relationship of the three points of the arch top, arch waist and arch foot is: 拱腰 =x 拱脚 / 2.

[0025] Preferably, the difference distance between the Z-axis coordinates of the arc position coordinate sequences of each section arch surface is calculated according to the mileage of the monitoring and measuring tunnel.

[0026] The beneficial effects of the present invention are:

[0027] The monitoring of the axis length of the tunnel is established through the three-dimensional model, and in the direction of the axis length of the tunnel, according to the monitoring distance of each section set in advance, the three-dimensional point cloud data is extracted, and the arc coordinate sequence of the section is extracted from the three-dimensional point cloud data of each section. According to the arc coordinate sequence of the tunnel, the monitoring of the three sides of the triangle formed by two points symmetrical about the Y axis and the Z axis on each section of the tunnel is realized, and the monitoring of the convergence value and the peripheral convergence is realized. Compared with the manual measurement method, the range of points sampled is larger, the sample data is more, and the data better reflects the deformation of the tunnel. By calculating the length of the three sides of multiple triangles in the tunnel section, the calculation of the peripheral convergence value and the convergence value of each section of the tunnel is realized, and the deformation of the tunnel is more accurately reflected; according to the fitting prediction of the b change curve function and the c change curve function, the deformation of the tunnel at the next time is predicted to realize the early warning of deformation; and then by comparing the b change curve function and the c change curve function, the deformation of each section of the tunnel is analyzed, and the deformation of the two sides symmetrical about the Y axis is realized in one section. Monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0029] Figure 1 A method step of the monitoring and measuring method of the present invention;

[0030] Figure 2 It is a schematic diagram of the three-dimensional coordinates of the first tunnel section of the present invention. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0032] The multi-section construction monitoring and measurement of tunnels is to set up multiple monitoring and measurement sections with different mileages according to the tunnel surrounding rock grade and on-site construction plan during the tunnel construction process, and set up multiple monitoring points on each monitoring and measurement section. Various types of instruments and tools are used to monitor the deformation and stress state of the surrounding rock and supporting lining in sections, providing key data support for construction safety and quality control.

[0033] In the monitoring and measurement of the tunnel segments, convergence is the key data reflecting the deformation and stress state of the surrounding rock and supporting lining. Convergence is the displacement of the surrounding rock into the cave due to the formation of the free surface after the tunnel is excavated. Among them, the peripheral convergence and convergence value measure the two sets of convergence data. The peripheral convergence is the relative displacement in the direction of the line connecting two points on the inner wall of the tunnel. Convergence is the difference in the measured distance. Due to the complexity of the tunnel surrounding rock geology, the tunnel section undergoes multi-directional and complex deformation. For example, the tunnel section may have a variety of deformation modes such as asymmetric convergence, distortion, and bulge. In this case, a measurement method with a large amount of sample data and reduced manual measurement is required. This embodiment provides a method for monitoring and measuring the construction of multi-section tunnels, including the following steps:

[0034] Step 1: Set up multiple monitoring measurement sections with different mileages according to the tunnel surrounding rock grade and on-site construction plan, that is, monitor the tunnel in sections;

[0035] Step 2: Use a 3D laser scanner to scan the tunnel to obtain the 3D point cloud data of the tunnel. Perform denoising and filtering on the point cloud data to improve the authenticity of the measurement data. Use cloud storage to store and manage the measurement data and subsequent calculation data, which is convenient for data extraction and can also prevent data loss. Due to the diverse terrain of the tunnel itself and the diversity of construction methods, the surrounding rock surface of the tunnel is not flat. There are convexities or depressions, which will cause the scanned point cloud data of the tunnel to be denoised and cleaned. For example, data structures such as KD-TREE can be used to efficiently process point cloud data to improve the authenticity of the measurement data.

[0036] Step 3: Obtain the arc coordinate sequence of each section of the tunnel, use the RANSAC algorithm to extract the tunnel axis from the point cloud data, establish a three-dimensional coordinate system with the tunnel section height direction as the Y axis, the tunnel section width direction as the X axis, the tunnel axis direction as the Z axis, and the tunnel starting point as the zero point, cut each tunnel section in the point cloud data at a certain distance pre-set in step 1, and extract the arc position coordinate sequence of each section of the tunnel according to the curvature and other characteristics of the point cloud data. The arc coordinate sequence here is the point cloud data of the tunnel contour;

[0037] Step 4: Calculate the peripheral convergence value of each section of the tunnel, extract the coordinates of two points symmetrical about the Y axis from the arch arc position coordinate sequence of each section, calculate the three sides of the triangle formed by the two points and the two points and Z respectively to generate a triangle side length subsequence {a, b, c}, where a is the interval between the two points, b is the interval between one of the points and the point Z=0, and c is the interval between the other point and Z=0. The subsequent triangle side length subsequences of the points symmetrical about the Y axis form a section triangle side length sequence {{a1, b1, c1}, ..., {an, bn, cn}}, where b and c values ​​are the distances between the two points symmetrical about the Y axis and the Z axis respectively, and the position of the Z axis on each section is equivalent to the center of the section fitting circle. b and c values ​​represent the radial distances from the two points to the center of the circle, so the measurement of the peripheral convergence value of the tunnel is achieved through b and c;

[0038] Repeat steps 1 to 4, generate the triangle side length sequence of each time interval t in each section respectively, and monitor the convergence of the periphery of each section of the tunnel through the change of b and c values, that is, realize the change of the radial distance between the points in each section and the center of the circle in the interval time, realize the monitoring of the convergence of the periphery, and extract the coordinates of the two points symmetrical about the Y axis from the arc coordinate sequence of the tunnel section at t n Time and t n+1 The horizontal coordinates of the corresponding position elements of the point set extracted by time are the same;

[0039] Step 5: Calculate the convergence value of each section of the tunnel, extract t at interval t n+1 Time and t n The distance difference between the two time-symmetric points is used to generate a distance difference sequence, and step 5 is repeated to use the distance difference between the two parallel points to monitor the convergence value of each section of the tunnel;

[0040] The convergence threshold is determined according to the tunnel monitoring specification, and an automatic alarm is issued when the peripheral convergence value obtained in step 4 exceeds the convergence threshold. Similarly, the peripheral convergence threshold needs to be determined according to the tunnel monitoring specification, and an automatic alarm is issued when the peripheral convergence value obtained in step 5 exceeds the peripheral convergence warning value.

[0041] Through the above method, the convergence value and peripheral convergence are monitored based on the lengths of the three sides of the triangles formed by two points symmetrical about the Y axis and the Z axis on each section of the tunnel. Compared with the manual measurement method, the range of sampled points is larger, the sample data is more, and the data better reflects the deformation of the tunnel. By calculating the lengths of the three sides of multiple triangles in the tunnel section, the peripheral convergence value and convergence value of each section of the tunnel are calculated, which more accurately reflects the deformation of the tunnel.

[0042] In one embodiment, in order to give early warning of the impending danger so as to facilitate early response, step 4 further includes: n+1 Time and t n The changes in the b and c values ​​at time generate the b change curve function and the c change curve function, and the change values ​​of b and c at the next time are predicted based on the b change curve function and the c change curve function. The change law of the distance difference over time is obtained, and the distance difference at the next time is calculated based on the distance difference function at each time, and an early warning is issued when it exceeds the surrounding convergence value.

[0043] In one embodiment, the deformation of the two sides symmetrical about the Y axis in each section of the tunnel is analyzed by comparing the b change curve function and the c change curve function. Because the b change curve function and the c change curve function respectively represent the radial deformation of the points on both sides of the tunnel symmetrical about the Y axis, the tunnel deformation of the two symmetrical surfaces in one section of the tunnel can be realized. By comparing the b change curve and the c change curve, the convergence of the local area in the tunnel section can be identified. If the b change curve and the c change curve both show similar convergence patterns, it means that the tunnel as a whole tends to be stable; if the convergence patterns of the b change curve and the c change curve are quite different, that is, the tunnel section has obvious asymmetry or abnormal changes, it may indicate that the tunnel structure in this area is at risk of instability. For example, if the convergence on one side is much greater than that on the other side, it may cause lining cracking or local collapse, and further measurement and analysis by construction personnel is required to deal with the danger in advance. Similarly, the b change curve and the c change curve between each section can also be compared and judged, so as to achieve further maintenance of the section with problems.

[0044] The vault settlement of a tunnel refers to the vertical settlement of the top of the tunnel (vault) during the construction of the tunnel, which reflects the stability of the tunnel surrounding rock and the bearing capacity of the supporting structure. By monitoring the vault settlement value, unstable factors in tunnel construction can be discovered in time, and corresponding measures can be taken to ensure construction safety and avoid accidents such as landslides. Therefore, in the monitoring and measurement of tunnels, the vault settlement is an important indicator. Therefore, by using a three-dimensional laser scanner and the subsequent establishment of a three-dimensional coordinate system in the aforementioned implementation method, the three-dimensional coordinates corresponding to each measuring point are obtained. Therefore, the vault settlement can be calculated by the obtained three-dimensional coordinates, reducing the process of re-exploring and measuring. In one implementation method, step 5 also includes extracting points with the same X-axis in the arch arc position coordinate sequence of each section to generate t n Time and t n+1The Y-axis difference sequence of time is used to generate the time-Y-axis difference function. The time-Y-axis difference function is used to represent the Y-axis change of the same point, that is, the point represented as the same X-axis in the coordinate system, that is, to predict the deformation of the vertical height of the tunnel, as a consideration for the subsequent estimation of the deformation of the tunnel surrounding rock. Among them, the Y-axis difference sequence of the tunnel section with zero X-axis is extracted, that is, the Y-axis difference sequence of this point is used to calculate the vault settlement. In this way, only three-dimensional laser scanning of the tunnel is required at time t to realize the calculation and prediction of multiple key measurement data, reducing the construction process.

[0045] The arch subsidence warning threshold is determined according to the tunnel monitoring specification, and an automatic alarm is issued when the obtained arch subsidence amount exceeds the arch subsidence warning threshold.

[0046] Since the selection of tunnel monitoring measurement points is crucial, the selected measurement points must be able to reflect the deformation of the tunnel, and in order to reduce the convenience of subsequent calculations, the number of selected measurement points should not be too large. Therefore, in one implementation, the following method is used to extract the coordinates of two points symmetrical about the Y axis in an arc coordinate sequence of a section:

[0047] A symmetry plane with the Y-axis direction in a section as the symmetry axis:

[0048] a: Select the cross-section vault, the arch haunch and the arch foot in the arch surface arc coordinate sequence:

[0049] b: Select the midpoint between two adjacent points among the three points to get the other two points:

[0050] c: Determine the number of cycles of step b according to the width of the tunnel, obtain the measurement points of a symmetric plane of the tunnel, and remove the overlapping points to obtain the horizontal coordinate set of the points {x1, ..., xn}, symmetric the elements in the point set about the Y axis, and obtain the horizontal coordinate set of two points symmetric about the Y axis in a section {{x1, xn} 1}, ..., {xn, x n}}, according to the extracted horizontal coordinate, the X-axis and Y-axis corresponding to the corresponding horizontal coordinate are extracted from the arch surface arc coordinate sequence.

[0051] In the above method, the X-axis relationship of the three points of the arch crown, arch waist and arch foot is:

[0052] x 拱腰 =x 拱脚 / 2, that is, the horizontal coordinate corresponding to the arch waist is the midpoint of the line connecting the arch crown and the arch foot.

[0053] In the above implementation, the reflection axis reflects the forward direction of the tunnel, so the distance difference between the Z-axis coordinates of the arch surface arc position coordinate sequences of each section is calculated according to the tunnel mileage measured by monitoring, that is, the Z-axis difference between each element in the i-th arch surface arc position coordinate sequence and the i+1-th arch surface arc position coordinate sequence is the distance difference between the i-th section and the i+1-th section, i≧1, and i is an integer. The advantage of establishing a three-dimensional coordinate system in this way is that when extracting and calculating point cloud data, it is easy to quickly locate the specific coordinates in the arch surface arc position coordinate sequence according to a large amount of tunnel coordinate data, and it is also convenient for the subsequent storage and management of large amounts of data.

[0054] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A tunnel multi-section construction monitoring and measurement method, characterized in that: The following steps are involved: Step 1: Determine the distance between each section of the tunnel, and set up multiple monitoring measurement sections with different mileages at a certain distance according to the tunnel surrounding rock grade and on-site construction plan; Step 2: Obtain the three-dimensional point cloud data of the tunnel, scan the tunnel with a three-dimensional laser scanner, obtain the three-dimensional point cloud data of the tunnel, and perform denoising and filtering on the point cloud data; Step 3: Obtain the arc coordinate sequence of each section of the tunnel, determine the tunnel axis, establish a three-dimensional coordinate system with the tunnel section height direction as the Y axis, the tunnel section width direction as the X axis, the tunnel axis direction as the Z axis, and the tunnel starting point as the zero point, cut each tunnel section at a certain distance in the point cloud data, and extract the arc position coordinate sequence of each section; Step 4: Calculate the peripheral convergence value of each section of the tunnel, extract the coordinates of two points symmetrical about the Y axis from the arch arc position coordinate sequence of each section, calculate the three sides of the triangle formed by the two points and the two points and Z respectively to generate a triangle side length subsequence {a, b, c}, where a is the interval between the two points, b is the interval between one of the points and Z=0, and c is the interval between the other point and Z=0. The subsequent triangle side length subsequences of the symmetrical points about the Y axis form a section triangle side length sequence {{a1, b1, c1}, ..., {an, bn, cn}}, and the measurement of the peripheral convergence value of the tunnel is achieved through b and c; Repeat steps 1 to 4, generate triangle side length sequences of each time interval t in each section respectively, and monitor the convergence of the perimeter of each section of the tunnel through the changes of b and c values; Step 5: Calculate the convergence value of each section of the tunnel, extract t at interval t n+1 Time and t n The distance difference between two time-symmetric points is subtracted to generate a distance difference sequence, and step 5 is repeated to monitor the convergence value of each section of the tunnel; The peripheral convergence value threshold and the convergence value threshold are determined according to the tunnel monitoring specification, and an automatic alarm is issued when the peripheral convergence value exceeds the peripheral convergence threshold or the convergence value exceeds the convergence value threshold.

2. A tunnel multi-section construction monitoring and measurement method according to claim 1, characterized in that: Step 4 also includes the following steps: n+1 Time and t n The changes in the b and c values ​​at time generate the b change curve function and the c change curve function, and the change values ​​of b and c at the next time are predicted based on the fitting of the b change curve function and the c change curve function, and an early warning will be issued when they exceed the surrounding convergence value.

3. A tunnel multi-section construction monitoring and measurement method according to claim 2, characterized in that: By comparing the b change curve function and the c change curve function, the deformation on both sides symmetrical about the Y axis in each section of the tunnel is analyzed.

4. A tunnel multi-section construction monitoring and measurement method according to claim 1, characterized in that: Step 5 also includes generating t in the arc position coordinate sequence of the arch surface of each section. n Time and t n+1 The Y-axis difference sequence of time is used to generate a time-Y-axis difference function to predict the deformation of the vertical height of the tunnel, wherein the vault settlement is extracted from the Y-axis difference sequence at the zero point.

5. A tunnel multi-section construction monitoring and measurement method according to claim 1, characterized in that: In step 4, the following method is used to extract the horizontal coordinates of two points symmetrical about the Y axis from the arc coordinate sequence of a section: A symmetry plane with the Y axis in a section as the symmetry axis: a: Select the cross-section vault, the arch waist and the arch foot in the arch surface arc coordinate sequence; b: Select the midpoint between two adjacent points among the three points to get the other two points; c: Determine the number of cycles of step b according to the width of the tunnel, obtain the measurement points of a symmetric plane of the tunnel, and remove the overlapping points to obtain the horizontal coordinate set of the points {x1, ..., xn}, symmetric the elements in the point set about the Y axis, and obtain the horizontal coordinate set of two points symmetric about the Y axis in a section {{x1, xn} 1 }, ..., {xn, x n }}, according to the extracted horizontal coordinate, the X-axis and Y-axis corresponding to the corresponding horizontal coordinate are extracted from the arch surface arc coordinate sequence.

6. A tunnel multi-section construction monitoring and measurement method according to claim 5, characterized in that: The X-axis relationship of the three points of the arch top, arch waist and arch foot is: 拱腰 =x 拱脚 / 2.

7. A tunnel multi-section construction monitoring and measurement method according to claim 6, characterized in that: The difference distance of the Z-axis coordinates of the arc position coordinate sequence of each section arch surface is calculated according to the monitoring and measuring tunnel mileage.

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