A method for detecting ballast replenishment amount on newly built lines based on vehicle-mounted laser scanning technology

Abstract

The present invention discloses a method for detecting the amount of ballast required for newly constructed lines based on vehicle-mounted laser scanning technology. Specifically, the method comprises: acquiring point cloud data of newly constructed lines using a vehicle-mounted laser scanning system; processing the point cloud data to accurately correct the line mileage; correcting the designed ballast section to adapt to different operating conditions; establishing a buffer zone of a certain thickness, projecting the point cloud within the buffer zone onto a cross-sectional coordinate system, simplifying the actual point cloud section by a certain width, and extracting the measured point cloud roadbed section; and calculating the amount of ballast required for that section of the route using the cross-sectional method based on the excess and insufficient areas of the section within each interval. The present invention can improve the efficiency of data collection, enhance the accuracy of ballast quantity calculations, and guide construction; and can significantly reduce the number of ballast laying operations, lower costs, and improve efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of rail transportation technology, and in particular relates to a method for detecting the amount of ballast replenishment for a newly built line based on vehicle-mounted laser scanning technology. Background Art

[0002] New ballasted railways require ballast laying to provide longitudinal and lateral resistance and the necessary elasticity for the track superstructure, ensuring safe and stable operation. Traditionally, this approach involves manually drawing a cross-section of the trackbed on-site, calculating the required ballast fill without considering the actual design cross-section. This can lead to significant deviations between the design and actual cross-sections, resulting in inaccurate ballast calculations and multiple ballast layings, increasing labor, costs, and time.

[0003] The existing technology for the discussion of the amount of ballast to be added after cleaning uses a combination of qualitative and quantitative analysis to determine the amount of ballast to be added to the line after cleaning. By selecting representative typical sections for analysis and calculation, the sections are measured on-site and manually drawn, and the difference between the ballast amount of the actual section after cleaning and the ballast amount of the designed section is calculated to obtain the ballast amount. This method obtains the measured section by measuring the section on-site and manually drawing the section diagram, and the representative typical sections selected are not applicable to any mileage of the line, and do not consider all basic types of section conditions. In the actual ballast amount calculation process, the railway line is long, and on-site measurement and manual drawing often require a lot of manpower, which lengthens the operation cycle and is not applicable to the calculation of ballast amount for large-scale lines.

[0004] Paper: The development of the trackbed profile measurement system is based on the principle of laser ranging scanning. The echo of the laser beam scanning the ballast surface is converted and processed, and the distance from the laser emission point to the ballast and the angle of the laser beam are used to form the actual profile of the measured trackbed. The deviation between the measured trackbed profile and the standard profile can be obtained through image comparison; after systematic integral calculation, the profit and loss of the section can be obtained. This method compares the measured trackbed profile with the standard profile and integrates it to obtain the ballast filling amount. It does not explain how to obtain the standard profile, and the standard profiles at different mileages are different. The standard profile is not adjusted, which leads to deviations in the calculation of the ballast filling amount, increases the number of ballast laying times, reduces construction efficiency, and increases work costs.

[0005] The paper, "Analysis of Ballast Quantity Calculation for Ramp-Up and Ramp-Down Sections of Existing Lines," considers the cross-section types of existing lines before and after improvement under three operating conditions and analyzes the calculation of ballast quantity for ramp-up and ramp-down sections of existing lines. This method fails to account for the effects of factors such as superelevation and line spacing on ballast quantity calculation, resulting in deviations in the actual calculated ballast quantity and making it difficult to apply to ballast quantity calculations for measured road conditions.

[0006] In summary, the prior art has the following disadvantages:

[0007] (1) The common practice on site is to first obtain the measured cross-section by on-site measurement and manual drawing, which results in low efficiency and high labor costs.

[0008] (2) The actual situation of the line shape is not taken into account. There is a difference between the designed section and the actual designed section. When the ballast replenishment amount is calculated by comparing the measured section with the designed section, the calculation accuracy is low, which is of limited help in reducing the number of ballast laying times. Summary of the Invention

[0009] This invention provides a method for detecting ballast replenishment on newly constructed railway lines using vehicle-mounted laser scanning technology. This method aims to accurately determine the amount of ballast replenishment applied to each section of the line during ballast laying operations on newly constructed railways, guiding subsequent ballast laying operations, improving efficiency, and reducing costs. Furthermore, it provides a technical means for quantitatively and rapidly assessing the quality of ballast laying after completion.

[0010] A method for detecting the amount of ballast added on a newly built line based on vehicle-mounted laser scanning technology of the present invention comprises the following steps:

[0011] Step 1: Obtain point cloud data of the new route: Use the vehicle-mounted laser scanning system to obtain point cloud data of the route section.

[0012] Step 2: Process the point cloud data of the newly created route and make precise corrections to the route mileage.

[0013] Step 2.1: Segment the point cloud to obtain the point cloud of the roadbed.

[0014] Step 2.2: After converting the point cloud to the engineering coordinate system, the trackbed point cloud is accurately corrected according to the rail design coordinates.

[0015] Step 2.3: Accurately correct the measured point cloud mileage.

[0016] Step 3: Modify the basic ballast section to adapt to different working conditions, so as to obtain a new line ballast quantity calculation model that is universal for the entire line.

[0017] Step 3.1: Modify the basic ballast section to adapt to different working conditions.

[0018] Step 3.1.1: Based on the distribution of foundation types, adaptively determine the foundation type and single or double track to see if there is any superelevation.

[0019] Step 3.1.1.1: Obtain the foundation type of the current roadbed through the actual offline project distribution list.

[0020] Step 3.1.1.2: Calculate the line spacing; within two adjacent mileage intervals where the line spacing changes, use the linear interpolation method to calculate the line spacing at the current position.

[0021] Step 3.1.1.3: Set superelevation in the transition curve segment: When the mileage to be calculated is located in the circular curve segment, the superelevation is a given fixed value; when the current position is located in the transition curve segment, the superelevation is a variable value and is also calculated using the linear interpolation method.

[0022] Step 3.1.2: Obtain the design ballast section at the current location through the basic ballast section and adjustment according to the line parameters.

[0023] Step 3.2: Extract the roadbed section from the measured point cloud.

[0024] Step 3.3: Align the designed ballast section and the point cloud roadbed section, calculate their intersection, and calculate the area of ​​each section in turn. The area where the actual section is higher than the designed ballast section is positive, which is the excess area; otherwise, it is negative, which is the insufficient area.

[0025] Step 3.3.1: Extract the left and right rails and continue to modify the point cloud roadbed section based on the track measurement data.

[0026] Step 3.3.2: Calculate the excess and missing areas based on the positional relationship between the designed ballast section and the actual section.

[0027] Step 3.4: Based on the excess and insufficient areas of the sections within each interval, calculate the amount of ballast required for that section of the route using the cross-section method at certain intervals.

[0028] Furthermore, the method for accurately correcting the measured point cloud mileage in step 2.3 is:

[0029] Step 2.3.1: Convert the point cloud to the engineering coordinate system.

[0030] Step 2.3.2: Accurately transform the trackbed point cloud according to the rail design coordinates.

[0031] Step 2.3.3: Use specific features in the point cloud to determine their true mileage and accurately calibrate the measured point cloud mileage.

[0032] Furthermore, the cross-section adjustment method in step 3.1.2 is:

[0033] Step 3.1.2.1: Establish a cross-section coordinate system with the center coordinate of the line as the origin. The horizontal direction is the X-axis, with the left track as the positive direction, and the vertical direction, i.e. the elevation direction, is the Y-axis, with the upward direction as the positive direction.

[0034] Step 3.1.2.1: Adjust the position of the inner point of the double line according to the line spacing.

[0035] Step 3.1.2.2: When superelevation exists, adjust the base ballast section by keeping the inner rail stationary and raising the outer rail. Calculate the rail rotation angle in the cross-section coordinate system using the superelevation and rail length, and record it as α.

[0036] Step 3.1.2.3: Rotate the two end points P1 and P5 of the sleeper by the same angle α around point O' to obtain the adjusted sleeper points P1' and P5'; point O' is the point where the center of the top of the left rail is perpendicular to the sleeper.

[0037] Step 3.1.2.4: The ballast shoulder points P2' and P6' on the left and right sides have a certain difference with the sleepers P1 and P5 at both ends, which is recorded as Δx L , Δy L , Δx R , Δy R .

[0038] Step 3.1.2.5: The intersection of the straight line with a slope of 1:1.75 passing through the ballast shoulder point P2' after adjustment and the straight line with a slope of 4% passing through the leftmost point P3 before adjustment is the adjusted left point P3'; to obtain the rightmost point P7', the straight line passing through points P2' and P3' is shifted to the right by a distance of one line spacing, which is recorded as straight line L 2'3' At the same time, according to the adjusted ballast shoulder point L 6' The slope of the straight line is 1:1.75, and the intersection of the two straight lines is calculated to be P7'.

[0039] Furthermore, Δ in step 3.1.1.2 is set to 1 mm.

[0040] Furthermore, in step 3.4.1, l is set to 0.3 m.

[0041] The beneficial technical effects of the present invention are:

[0042] (1) According to this method, high-precision point cloud data is obtained, and the mileage of the point cloud is accurately calibrated to make the point cloud consistent with the actual situation, which can improve the efficiency of data collection, improve the accuracy of ballast filling calculation and guide construction.

[0043] (2) According to this method, the designed section is adjusted to make it consistent with the actual standard section, which improves the accuracy of the calculation of the ballast replenishment amount, can significantly reduce the number of ballast laying times, reduce costs and improve efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is the overall flow chart of the present invention.

[0045] Figure 2 This is a schematic diagram of the double-line subgrade cross section.

[0046] Figure 3 This is a schematic diagram of the outer rail superelevation section of the left line of the double-track subgrade section.

[0047] Figure 4 This is a schematic diagram of the cross section of a double-track tunnel.

[0048] Figure 5 Schematic diagram of the cross-sectional coordinate system.

[0049] Figure 6 Schematic diagram of the positional relationship between the designed ballast cross-section profile and the simplified cross-section profile. DETAILED DESCRIPTION

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0051] The present invention utilizes non-contact measurement technologies such as vehicle-mounted laser scanning systems to obtain point cloud data of line sections, and utilizes specific landforms such as tracks to accurately correct line mileage. The design section is adjusted based on a given design section, combined with line parameters, foundation type, line spacing, and superelevation lists. The ballast replenishment amount is calculated using the cross-section method based on the area difference between the adjusted design section and the measured section.

[0052] The present invention is a new line ballast quantity detection method based on vehicle-mounted laser scanning technology. Figure 1 As shown, the following steps are included:

[0053] Step 1: Obtain point cloud data of the new route: Use the vehicle-mounted laser scanning system to obtain point cloud data of the route section.

[0054] Step 2: Process the point cloud data of the newly created route and make precise corrections to the route mileage.

[0055] Step 2.1: Segment the point cloud to obtain the point cloud of the roadbed.

[0056] Step 2.2: After converting the point cloud to the engineering coordinate system, the trackbed point cloud is accurately corrected according to the rail design coordinates.

[0057] Step 2.3: Use specific features such as tracks in the point cloud to determine their true mileage and accurately calibrate the measured point cloud mileage.

[0058] Step 3: Modify the designed ballast section to adapt to different working conditions, so as to obtain a new line ballast quantity calculation model that is universal for the entire line.

[0059] Step 3.1: Modify the designed ballast section to adapt to different working conditions.

[0060] Step 3.1.1: According to the distribution of foundation types, adaptively judge the foundation type and single and double lines to see if there is superelevation. In the embodiment of the present invention, the foundation type of the newly built line is roadbed, and the single and double line type is double line. Its cross-sectional diagram is as follows: Figure 2 shown.

[0061] Step 3.1.1.1: Obtain the foundation type of the current roadbed through the actual offline project distribution list.

[0062] Step 3.1.1.2: Calculate the line spacing, which is the distance between the centerlines of two adjacent tracks (lines). Within the interval between two adjacent mileages where the line spacing varies, use linear interpolation to calculate the line spacing at the mileage. Linear interpolation is defined as a method that uses geometric relationships based on known mileages and line spacing to approximate the unknown line spacing at the mileage to be calculated, as shown in the following formula:

[0063]

[0064] Where LS represents the line spacing, LS0 represents the line spacing at mile0, LS1 represents the line spacing at mile1, mile0 and mile1 are given adjacent miles, mile represents the mileage to be calculated, and Δ represents the threshold for the mileage difference. In this embodiment, Δ is set to 1 mm.

[0065] Step 3.1.1.3: Superelevation is the elevation difference between the top of the outer rail and the top of the inner rail of a curved track. It is set on a transition curve. When the mileage to be calculated is on a circular curve, the superelevation is a fixed value. When the mileage to be calculated is on a transition curve, the superelevation is a variable value. It is also calculated using linear interpolation, as shown in the following formula:

[0066]

[0067] Where H is the superelevation at the mileage to be determined, H0 is the superelevation at the circular curve, and mile ZH Mileage for straight line HZ Mileage for straight line HY Mileage for slow dots, mile YH To slow down the mileage.

[0068] Step 3.1.2: Design ballast section adjustment. Figure 3 As shown, there is outer rail superelevation on the left line of the double-track section, and the outer rail superelevation in the embodiment is adjusted.

[0069] Step 3.1.2.1: Establish a cross-sectional coordinate system with the center coordinate of the line as the origin, with the horizontal axis as X, pointing to the left track as positive, and the vertical axis as Y, with upward as positive; the cross-sectional coordinate system diagram is as follows: Figure 5 Adjust the position of point P7' on the right side according to the line spacing, as shown in the following formula:

[0070]

[0071] P7'.y=K*P7.x+P6.yK*P6.x

[0072] Where K is the slope gradient.

[0073] Step 3.1.2.2: When superelevation exists, the inner rail remains unchanged and the outer rail is raised; the rotation angle of the rail in the cross-section coordinate system is calculated by the superelevation and the rail length, which is recorded as α. Figure 5 As shown, the calculation formula is:

[0074]

[0075] Where H is the superelevation and RailLength is the distance between the centers of the left and right rail tops.

[0076] Step 3.1.2.3: Rotate the two end points P1 and P5 of the sleeper by the same angle α around point O' to obtain the adjusted sleeper points P1' and P5'; point O' is the point where the center of the top of the left rail is perpendicular to the sleeper.

[0077] Step 3.1.2.4: The ballast shoulder points P2' and P6' on the left and right sides have a certain difference with the sleepers P1 and P5 at both ends, which is recorded as Δx L , Δy L , Δx R , Δy R .

[0078] Step 3.1.2.5: The intersection of the straight line with a slope of 1:1.75 passing through the ballast shoulder point P2' after adjustment and the straight line with a slope of 4% passing through the leftmost point P3 before adjustment is the adjusted left point P3'; to obtain the rightmost point P7', the straight line passing through points P2' and P3' is shifted to the right by a distance of one line spacing, which is recorded as straight line L 2'3' At the same time, according to the adjusted ballast shoulder point L 6' The slope of the straight line is 1:1.75, and the intersection of the two straight lines is calculated to be P7'.

[0079] The present invention does not impose any formal or parametric limitations on the double-track base section. Other situations, such as the superelevation of the outer rail of the right line of the double-track base, the superelevation of the left and right lines of the double-track bridge, and the superelevation of the left and right lines of the double-track tunnel, are all within the scope of protection of the present invention.

[0080] When the track is single-track, the track spacing does not need to be considered. By determining the superelevation, adaptive adjustments are made to the sleeper points P1 and P5, the ballast shoulder points P2 and P6, and the ballast foot points P3 and P7. For double-track, the impact of the track spacing on the position of the ballast foot points P3 or P7 is first considered. Then, by determining the superelevation, adaptive adjustments are made to the sleeper points P1 and P5, the ballast shoulder points P2 and P6, and the ballast foot points P3 and P7.

[0081] Step 3.1.3: When the base type is tunnel, add P4 and P8 (such as Figure 4The horizontal coordinate of point P4 is half the known tunnel width, and the vertical coordinate is the same as that of point P3. When it is the right line, there is an additional point P8, and the difference between it and point P4 is that the horizontal coordinate is the opposite number.

[0082] Step 3.2: Create a buffer zone of a certain thickness d, project the point cloud in the buffer zone onto the cross-section coordinate system, simplify the actual point cloud cross section according to a certain width w, and extract the measured point cloud roadbed cross section.

[0083] Step 3.3: Align the two sections, calculate their intersection, and calculate the area of ​​each section in turn. The area where the actual section is higher than the designed ballast section is positive, which is the excess area; otherwise, it is negative, which is the insufficient area.

[0084] Step 3.3.1: Align the measured point cloud section with the adjusted designed ballast section; due to the error of the measured point cloud scanning, in order to ensure the accuracy of the area difference between the section and the measured point cloud section and the subsequent ballast filling amount calculation, the coordinates of the left and right rails are extracted, and the data from the track inspection trolley is used as the reference, and then the extracted actual point cloud rail coordinates are aligned with it.

[0085] Step 3.3.2: Determine the positive and negative cross-sectional area based on the positional relationship between the designed ballast section and the actual section; calculate the intersection point between the two sections after alignment to determine the excess and missing areas.

[0086] Step 3.3.3: The intersection of the two sections can be obtained based on the designed ballast section profile and the simplified section profile. The position relationship between the designed ballast section profile and the simplified section profile is as follows: Figure 6 As shown in the figure, taking S1 as an example, in the actual point cloud section, the first and last points are (x1, y1) and (x n ,y n ), and the point of the designed ballast section is known, which is the last point and the intersection point. Therefore, the area of ​​the closed figure enclosed by the designed ballast section and the actual point cloud section is S1, which is calculated by the polygon area calculation formula:

[0087]

[0088] Where n is the number of polygon points, (x i ,y i ) are the coordinates of each point in the polygon, and the points are distributed counterclockwise from i=1 to n. Traverse the area of ​​each polygon and obtain the excess and missing areas of the entire cross section.

[0089] Step 3.4: Based on the excess and insufficient areas of the sections within each interval, calculate the amount of ballast required for that section of the route using the cross-section method at certain intervals.

[0090] Step 3.4.1: Set the section spacing l, and generate a section every distance l along the line mileage direction. The distance interval l can be set according to needs. In the embodiment of the present invention, the value is set to 0.3m.

[0091] Step 3.4.2: Calculate the excess and insufficient area ΔS of the actual section relative to the designed ballast section i .

[0092] Step 3.4.3: Based on the distance l between two adjacent sections and the excess and insufficient areas ΔS calculated in step 3.4.2 i , integral calculation of excess ballast and insufficient ballast ΔV between two adjacent sections i , the ballast filling amount is calculated by the following formula:

[0093]

[0094] Step 3.5: Traverse all interval sections and repeat steps 3.1 to 3.4 for each interval section to calculate the excess ballast and insufficient ballast within the corresponding mileage range.

[0095] Therefore, the present invention solves the problems of large workload and low accuracy in the existing method of calculating the ballast amount by manually drawing the roadbed cross-section diagram, and proposes a new line ballast amount detection method based on vehicle-mounted laser scanning technology, which realizes the rapid and accurate calculation of the ballast amount.

Claims

1. A method for detecting the amount of ballast added on a new line based on vehicle-mounted laser scanning technology, characterized in that: The following steps are involved: Step 1: Obtain point cloud data for the new route: Use the vehicle-mounted laser scanning system to obtain point cloud data of the route section; Step 2: Process the point cloud data of the newly created route and make accurate corrections to the route mileage; Step 2.1: Segment the point cloud to obtain the point cloud of the roadbed; Step 2.2: After converting the point cloud to the engineering coordinate system, the trackbed point cloud is accurately corrected according to the rail design coordinates; Step 2.3: Accurately correct the measured point cloud mileage; Step 2.3.1: Convert the point cloud to the engineering coordinate system; Step 2.3.2: Accurately convert the trackbed point cloud according to the rail design coordinates; Step 2.3.3: Use specific features in the point cloud to determine their true mileage and accurately calibrate the measured point cloud mileage; Step 3: Modify the basic ballast section to adapt to different working conditions, so as to obtain a new line ballast quantity calculation model that is universal for the entire line; Step 3.1: Modify the basic ballast section to adapt to different working conditions; Step 3.1.1: Based on the distribution of foundation types, adaptively determine the foundation type and whether there is superelevation, single or double track; Step 3.1.1.1: Obtain the current roadbed foundation type through the actual offline project distribution list; Step 3.1.1.2: Calculate the line spacing; within two adjacent mileage intervals where the line spacing changes, use linear interpolation to calculate the line spacing at the current position; Step 3.1.1.3: Set superelevation on a transition curve segment: When the mileage to be calculated is on a circular curve segment, the superelevation is a given fixed value; when the current position is on a transition curve segment, the superelevation is a variable value and is also calculated using the linear interpolation method. Step 3.1.2: Obtain the design ballast section at the current location by adjusting the basic ballast section according to the line parameters; Step 3.2: Extract the roadbed section from the measured point cloud; Step 3.3: Align the designed ballast section and the point cloud roadbed section, calculate their intersection, and calculate the area of ​​each section in turn. The area where the actual section is higher than the designed ballast section is positive, which is the excess area; otherwise, it is negative, which is the insufficient area. Step 3.3.1: Extract the left and right rails and continue to modify the point cloud roadbed section based on the track measurement data; Step 3.3.2: Calculate the excess and missing areas based on the positional relationship between the designed ballast section and the actual section; Step 3.4: Based on the excess and insufficient areas of the sections within each interval, calculate the amount of ballast required for that section of line according to the cross-section method at certain intervals.

2. The method for detecting the amount of ballast added on a new line based on vehicle-mounted laser scanning technology according to claim 1 is characterized in that: The cross-section adjustment method in step 3.1.2 is as follows: Step 3.1.2.1: Establish a cross-section coordinate system with the center coordinate of the line as the origin. The horizontal direction is the X-axis, with the left track as the positive direction, and the vertical direction, i.e. the elevation direction, is the Y-axis, with the upward direction as the positive direction; Step 3.1.2.1: Adjust the position of the inner point of the double line according to the line spacing; Step 3.1.2.2: When superelevation exists, the inner rail is fixed and the outer rail is raised to adjust the base ballast section. The rotation angle of the rail in the section coordinate system is calculated by the superelevation and the rail length, which is recorded as α. Step 3.1.2.3: Rotate the two end points P1 and P5 of the sleeper by the same angle α around point O' to obtain the adjusted sleeper points P1' and P5'; point O' is the point where the center of the left rail top is perpendicular to the sleeper; Step 3.1.2.4: The ballast shoulder points P2' and P6' on the left and right sides have a certain difference with the sleepers P1 and P5 at both ends, which is recorded as Δx L , Δy L , Δx R , Δy R ; Step 3.1.2.5: After adjustment, the slope of the ballast shoulder point P2' is 1: The intersection of the straight line of 1.75 and the straight line passing through the leftmost point P3 before adjustment and with a slope of 4% is the adjusted left point P3'; to obtain the rightmost point P7', the straight line passing through points P2' and P3' is shifted to the right by a distance of one line spacing, which is recorded as straight line L 2′3′ At the same time, according to the adjusted ballast shoulder point L 6′ The slope of is 1: 1.75, the intersection of the two straight lines is calculated as P7'.

Images