Assembling method and system of BIM-based assembled box culvert

Abstract

This invention provides a BIM-based prefabricated box culvert assembly method and system, belonging to the field of prefabricated box culvert technology. Based on BIM technology, this invention proposes a multi-dimensional quality evaluation method for box culvert assembly, realizing quantitative analysis of the quality and spatial distribution of box culvert sub-modules, generating an assembly center of gravity evaluation index, which effectively reflects the stability of the center of gravity and shape distortion during the assembly process. Simultaneously, through geometric correlation analysis of the normal vectors of the upper and lower contact planes of the box culvert, a box culvert flatness index is constructed, comprehensively reflecting the flatness between the assembly surfaces of the box culvert. Finally, the box culvert center of gravity evaluation index and the flatness index are coupled to form an assembly evaluation index, quantifying the assembly quality. This allows for sensitive and accurate judgment of assembly anomalies and risks based on the box culvert's shape, significantly improving the efficiency and accuracy of box culvert assembly inspection, facilitating timely adjustment and optimization of the scheme, and reducing potential safety hazards in the box culvert structure.

Description

Technical Field

[0001] This invention relates to the field of prefabricated box culvert technology, specifically to a BIM-based prefabricated box culvert assembly method and system. Background Technology

[0002] Prefabricated box culverts are a type of culvert structure that uses prefabricated components manufactured in a factory and rapidly assembled on-site. They are widely used in infrastructure construction such as roads, railways, municipal drainage, and underground utility tunnels. Compared to traditional cast-in-place concrete box culverts, prefabricated box culverts offer advantages such as shorter construction cycles, easier quality control, less impact on the on-site construction environment, and higher resource utilization. Through standardized design and modular production, prefabricated box culvert components can achieve precise dimensional control and high-quality manufacturing, reducing on-site concrete pouring and curing processes and significantly improving construction efficiency. Furthermore, prefabricated box culverts possess excellent seismic performance and durability, meeting the engineering requirements under complex geological and environmental conditions. BIM (Building Information Modeling) is used in the design and installation of box culverts; it is a digital design and construction method that integrates various information about a building project using a three-dimensional model.

[0003] Current technologies for evaluating the quality of box culvert assembly are relatively crude, relying mainly on manual inspection or single geometric dimensional deviations, which makes it difficult to comprehensively and accurately reflect the overall quality of box culvert assembly. In particular, the lack of unified quantitative indicators and systematic analysis methods in the comprehensive evaluation of key indicators such as box culvert center of gravity shift, shape distortion, and flatness makes it difficult to effectively monitor and evaluate assembly quality, thereby affecting the long-term structural performance and safety of box culverts.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for assembling prefabricated box culverts based on BIM, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The assembly method for prefabricated box culverts based on BIM includes the following steps:

[0008] S1. Number the N box culverts, divide each box culvert into multiple sub-modules, collect the point cloud data of the sub-modules and import them into the 3D modeling software to generate the sub-module model;

[0009] S2. Place the sub-module model in a three-dimensional coordinate system, perform correlation analysis on the sub-module to generate sub-module quality, perform correlation analysis on the sub-module quality to generate the center of gravity coordinates of the box culvert model, and perform correlation analysis on the center of gravity coordinates of the box culvert to generate the center of gravity offset XZP, the box culvert deviation XPP, and the center of gravity height XZG of the box culvert model. The box culvert deviation XPP is used to reflect the degree of deformity of the overall shape of the box culvert, the center of gravity offset XZP is used to reflect the stability of the center of gravity of the box culvert, and the center of gravity height XZG is used to reflect the height of the overall center of gravity of the box culvert. Perform correlation analysis on the center of gravity offset XZP, the box culvert deviation XPP, and the center of gravity height XZG of the box culvert model to generate the assembly center of gravity evaluation index PZP.

[0010] S3. Obtain the plane coordinates of each box culvert, including the upper and lower plane coordinates. Perform correlation analysis on the plane coordinates to generate the box culvert plane equation. Perform correlation analysis on the box culvert plane equation to generate the box culvert flatness index XPZ.

[0011] S4. Perform correlation analysis on the box culvert smoothness index XPZ and center of gravity evaluation index PZP to generate the assembly evaluation index PP. The assembly evaluation index PP is used to reflect the quality of the box culvert assembly. Compare the assembly evaluation index PP with the threshold to output the assembly evaluation level.

[0012] Furthermore, the N box culverts are numbered in ascending order. Each box culvert model is divided into M sub-modules. Point cloud data of all sub-modules are acquired using LiDAR and imported into the modeling software to generate sub-module models. The volume of the j-th sub-module of the i-th box culvert is... .

[0013] Furthermore, correlation analysis is performed on the submodules to generate submodule quality data. The formula used is: ;

[0014] Among them, submodule quality This is used to reflect the quality of the j-th submodule of the i-th box culvert, and the quality of the i-th box culvert. for , Let be the density of the j-th submodule of the i-th box culvert;

[0015] Perform correlation analysis on the quality of sub-modules to generate the centroid coordinates of the i-th box culvert model. The formula used is:

[0016] ;

[0017] in, Let be the centroid coordinates of the j-th submodule of the i-th box culvert model;

[0018] For the centroid coordinates of the box culvert model Correlation analysis was performed to generate the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG, based on the following formula: ;

[0019] Among them, the box culvert deviation XPP is used to reflect the degree of deviation between other box culverts and the bottommost box culvert, and to reflect the degree of deformity of the overall shape of the box culvert; the box culvert model center of gravity offset XZP is used to reflect the degree of deviation between the comprehensive center of gravity of other box culverts and the center of gravity of the bottommost box culvert, and to reflect the stability of the center of gravity of the box culvert; and the box culvert center of gravity height XZG is used to reflect the height assessment value of the center of gravity of the box culvert.

[0020] Furthermore, a correlation analysis was conducted on the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG to generate the assembly center of gravity evaluation index PZP, based on the following formula:

[0021] ;

[0022] Where H is the height of the assembled box culvert, L is the length of the box culvert, and the assembly center of gravity evaluation index PZP is used to reflect the evaluation degree of the box culvert assembly in terms of the center of gravity.

[0023] Furthermore, let the equation of the upper plane of the i-th box culvert be: The equation of the lower plane of the i-th box culvert is: The constraints are:

[0024] ;

[0025] Construct the covariance matrix of the coordinate points on the plane of the box culvert, and obtain the eigenvalues ​​and corresponding eigenvectors of the covariance matrix. The eigenvector corresponding to the smallest eigenvalue is the plane normal vector, and the plane normal vector of the i-th box culvert is... The normal vector of the lower plane of the (i+1)th box culvert .

[0026] Furthermore, the normal vector of the upper plane of the i-th box culvert... The normal vector of the lower plane of the (i+1)th box culvert Correlation analysis was performed to generate the box culvert smoothness index XPZ, based on the following formula:

[0027] ;

[0028] Among them, the box culvert flatness index XPZ is used to reflect the flatness between the contact surfaces of the box culvert.

[0029] Furthermore, a correlation analysis was conducted on the box culvert smoothness index XPZ and the center of gravity evaluation index PZP to generate the assembly evaluation index PP, based on the following formula:

[0030] ;

[0031] The Assembly Evaluation Index (PP) is used to reflect the quality of assembly of box culverts from a shape perspective.

[0032] Furthermore, the assembly evaluation index PP is compared with the threshold. When a comparison is performed, At that time, the assembly level of the output box culvert was Level II. At this point, the assembly of the box culvert was highly dangerous and required redesign and adjustments. At that time, the assembly level of the output box culvert is Level 1, and no readjustment is required.

[0033] This invention also provides a BIM-based prefabricated box culvert assembly system for executing a BIM-based prefabricated box culvert assembly method, including:

[0034] The model building module is used to number the box culverts, collect the point cloud data of the box culverts and import it into the modeling software to generate box culvert models. Each box culvert is divided into several sub-modules.

[0035] The center of gravity analysis module is used to place the box culvert model in a three-dimensional coordinate system, perform correlation analysis on sub-modules, generate sub-module quality, perform correlation analysis on sub-module quality, generate the center of gravity coordinates of the box culvert model, perform correlation analysis on the center of gravity coordinates of the box culvert, generate the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model, and perform correlation analysis on the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model to generate the assembly center of gravity evaluation index PZP.

[0036] The flatness analysis module is used to obtain the plane coordinates of each box culvert, including the upper and lower plane coordinates. Correlation analysis is performed on the plane coordinates to generate the box culvert plane equation. Correlation analysis is then performed on the box culvert plane equation to generate the box culvert flatness index XPZ.

[0037] The output module is used to perform correlation analysis on the box culvert flatness index XPZ and the center of gravity evaluation index PZP, generate the assembly evaluation index PP, compare the assembly evaluation index PP with the threshold, and output the assembly evaluation level.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] This invention, based on BIM technology, proposes a multi-dimensional quality evaluation method for box culvert assembly. By combining point cloud data modeling, it achieves quantitative analysis of the quality and spatial distribution of box culvert sub-modules, generating an assembly center of gravity evaluation index. This index effectively reflects the stability of the center of gravity and shape distortion during the box culvert assembly process. Simultaneously, through geometric correlation analysis of the normal vectors of the upper and lower contact planes of the box culvert, a box culvert flatness index is constructed, comprehensively reflecting the flatness between the assembly surfaces. Finally, the box culvert center of gravity evaluation index and the flatness index are coupled to form an assembly evaluation index, quantifying the assembly quality. This method can sensitively and accurately judge assembly anomalies and risks based on the box culvert's shape, significantly improving the efficiency and accuracy of box culvert assembly inspection, facilitating timely adjustment and optimization of the scheme, and reducing potential safety hazards in the box culvert structure. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall method flow of the present invention;

[0041] Figure 2 This is a schematic diagram of the overall system modules of the present invention;

[0042] Figure 3 This is a fitting curve diagram of XZG-PZP of the present invention;

[0043] Figure 4 This is a fitting curve diagram of XZP-PZP of the present invention;

[0044] Figure 5 This is a fitting curve diagram of XPP-PZP of the present invention;

[0045] Figure 6 This is a fitting curve diagram of XPZ-PP of the present invention;

[0046] Figure 7 This is a fitting curve diagram of PZP-PP of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0048] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] Example:

[0050] Please see Figure 1 The present invention provides a technical solution:

[0051] The BIM-based prefabricated box culvert assembly method is used to evaluate the vertical assembly stability of the box culvert. Specific steps include:

[0052] Step 1: Number the N box culverts, divide each box culvert into multiple sub-modules, collect the point cloud data of the sub-modules and import them into the 3D modeling software to generate the sub-module model;

[0053] N box culverts are numbered in ascending order. Each box culvert model is divided into M sub-modules. Point cloud data of all sub-modules are acquired using LiDAR and imported into modeling software to generate sub-module models. The volume of the j-th sub-module of the i-th box culvert is... .

[0054] Step 2: Place the box culvert model in a three-dimensional coordinate system, perform correlation analysis on the sub-modules to generate sub-module quality, perform correlation analysis on the sub-module quality to generate the center of gravity coordinates of the box culvert model, and perform correlation analysis on the center of gravity coordinates of the box culvert to generate the center of gravity offset XZP, the box culvert deviation XPP, and the center of gravity height XZG of the box culvert model. The box culvert deviation XPP is used to reflect the degree of deformity of the overall shape of the box culvert, the box culvert center of gravity offset XZP is used to reflect the stability of the center of gravity of the box culvert, and the box culvert center of gravity height XZG is used to reflect the height of the overall center of gravity of the box culvert. Perform correlation analysis on the box culvert center of gravity offset XZP, the box culvert deviation XPP, and the box culvert center of gravity height XZG to generate the assembly center of gravity evaluation index PZP.

[0055] Perform correlation analysis on submodules to generate submodule quality. The formula used is: ;

[0056] Among them, submodule quality This is used to reflect the quality of the j-th submodule of the i-th box culvert, and the quality of the i-th box culvert. for , Let be the density of the j-th submodule of the i-th box culvert;

[0057] Perform correlation analysis on the quality of sub-modules to generate the centroid coordinates of the i-th box culvert model. The formula used is:

[0058] ;

[0059] in, Let be the centroid coordinates of the j-th sub-module of the i-th box culvert model. The centroid coordinates can be directly obtained by 3D software. Dividing the box culvert into sections and analyzing the centroid can improve the accuracy of the analysis.

[0060] For the centroid coordinates of the box culvert model Correlation analysis was performed to generate the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG, based on the following formula: ;

[0061] Where H represents the height of the assembled box culvert, and the box culvert deviation XPP reflects the degree of deviation between other box culverts and the bottommost box culvert, indicating the degree of overall shape distortion of the box culvert. A higher XPP value indicates a higher degree of overall distortion and worse stability. The box culvert model center of gravity offset XZP reflects the degree of deviation between the combined center of gravity of other box culverts and the center of gravity of the bottommost box culvert, indicating the stability of the box culvert's center of gravity. A higher XZP value indicates a higher degree of overall shape distortion and worse stability. A larger value indicates that the center of gravity of each box culvert deviates from the center of gravity of the lowest box culvert, resulting in an unstable center of gravity position of the assembled box culvert and a worse overall stability. The box culvert center of gravity height XZG is used to reflect the height assessment value of the box culvert's center of gravity. The box culvert center of gravity height XZG is used to reflect the sum of the center of gravity heights of each box culvert. The larger the value of the box culvert center of gravity height XZG, the higher the overall center of gravity of the box culvert, which in turn leads to a worse overall stability. The lower the overall center of gravity of the box culvert, the less susceptible it is to external interference, and the better its stability.

[0062] A correlation analysis was performed on the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG to generate the assembly center of gravity evaluation index PZP. The formula used is as follows:

[0063] ;

[0064] Where H is the height of the assembled box culvert, L is the length of the box culvert, and is the average value. The assembly center of gravity evaluation index PZP is used to reflect the evaluation degree of the box culvert assembly in terms of the center of gravity.

[0065] The overall center of gravity height XZG of the box culvert is standardized as a proportion relative to the total height H of the box culvert. Its relative height is calculated, and the design of adding 1 ensures that this item is always greater than or equal to 1, avoiding the product from being too small and causing the evaluation index to decrease, thus reflecting the basic contribution of the center of gravity height to the assembly stability. In this part, the sigmoid function provides a smooth threshold-type response, comparing the center of gravity offset XZP with the box culvert length L as a reference value, thereby reflecting the nonlinear effect of the center of gravity offset on the assembly quality. When the offset exceeds the box culvert length, the risk increases significantly. In this section, shape deformity significantly affects assembly quality. Its contribution is amplified using a squared form; the larger the deviation, the higher the evaluation index, reflecting the increased convexity of risk. When the values ​​of the box culvert model's center of gravity offset (XZP), box culvert deviation (XPP), and box culvert center of gravity height (XZG) increase, the assembly center of gravity evaluation index (PZP) rises, and the box culvert assembly stability decreases.

[0066] Step 3: Obtain the plane coordinates of each box culvert, including the upper and lower plane coordinates. Perform correlation analysis on the plane coordinates to generate the box culvert plane equation. Perform correlation analysis on the box culvert plane equation to generate the box culvert flatness index XPZ.

[0067] Let the equation of the upper plane of the i-th box culvert be: The equation of the lower plane of the i-th box culvert is: The constraints are:

[0068] ;

[0069] Construct the covariance matrix of the coordinate points on the plane of the box culvert, and obtain the eigenvalues ​​and corresponding eigenvectors of the covariance matrix. The eigenvector corresponding to the smallest eigenvalue is the plane normal vector, and the plane normal vector of the i-th box culvert is... The normal vector of the lower plane of the (i+1)th box culvert , Let constant terms be defined for the equation of the upper plane of the i-th box culvert. This is a constant term defined for the lower plane equation of the i-th box culvert. The subscripts i and i+1 are used to index the box culvert.

[0070] The covariance matrix reflects the distribution characteristics and dispersion of coordinate points in a plane along various directions. First, each coordinate point is centered; the centered coordinates form a matrix, and the covariance matrix is ​​then obtained. ,in The coordinates of each point after centering are given, and k is used to index the coordinates on the plane. There are a total of K coordinate points. Eigenvalue decomposition is performed on the covariance matrix, and the eigenvector corresponding to the smallest eigenvalue is selected as the plane normal vector. Substituting this into the plane equation yields the result. and The value of .

[0071] The normal vector of the upper plane of the i-th box culvert The normal vector of the lower plane of the (i+1)th box culvert Correlation analysis was performed to generate the box culvert smoothness index XPZ, based on the following formula:

[0072] ;

[0073] Among them, the box culvert flatness index XPZ is used to reflect the flatness between the contact surfaces of the box culvert. The value reflects the angle between the upper plane of the i-th box culvert and the lower plane of the (i+1)-th box culvert. The larger the angle, the more obvious the tilt or misalignment between the planes, indicating a poorer assembly flatness.

[0074] Step 4: Perform correlation analysis on the box culvert flatness index XPZ and center of gravity evaluation index PZP to generate the assembly evaluation index PP. The assembly evaluation index PP is used to reflect the quality of the box culvert assembly. Compare the assembly evaluation index PP with the threshold to output the assembly evaluation level.

[0075] A correlation analysis was conducted on the box culvert smoothness index XPZ and the center of gravity evaluation index PZP to generate the assembly evaluation index PP. The formula used is as follows:

[0076] ;

[0077] The assembly evaluation index PP is used to reflect the quality of assembly of box culverts from the perspective of shape. The larger the value of the box culvert flatness index XPZ, the worse the flatness between the box culverts, and the larger the assembly evaluation index PP value. The larger the value of the center of gravity evaluation index PZP, the worse the center of gravity stability between the box culverts, and the larger the assembly evaluation index PP value. The flatness index is amplified to emphasize the impact of flatness on assembly quality. Taking the natural logarithm of the centroid evaluation index makes the values ​​smoother and avoids extreme results caused by abnormally large centroid indices, while ensuring the validity of the input value range. Taking the logarithm of the product of the two parts again suppresses extreme values ​​and keeps the results within a reasonable range, which is beneficial for subsequent threshold judgment.

[0078] Collect XPZ and PZP data and corresponding construction quality grades from a large number of historical assembly projects. Calculate the corresponding PP index and determine a reasonable threshold through statistical analysis. Compare the assembly evaluation index PP with the threshold. When a comparison is performed, At that time, the assembly level of the output box culvert was Level II. At this point, the assembly of the box culvert was highly dangerous and required redesign and adjustments. At that time, the assembly level of the output box culvert is Level 1, and no readjustment is required.

[0079] Reference Figure 3-7 ,in Figure 3-5 The fitted curve of the assembly center of gravity evaluation index PZP formula is shown. Figure 6 and Figure 7 The fitting curve of the assembly evaluation index PP formula was plotted, and the statistical data was compiled and summarized in Table 1:

[0080] Table 1: Statistics of Assembly Center of Gravity Evaluation Index (PZP) and Assembly Evaluation Index (PP)

[0081]

[0082] in, Figures 3-5 The figure shows the fitting curves of XZG, XZP, XPP and the assembly center of gravity evaluation index PZP respectively. The figure shows that when the values ​​of the box culvert model center of gravity offset XZP, box culvert deviation XPP and box culvert center of gravity height XZG increase, the assembly center of gravity evaluation index PZP increases and the assembly stability of the box culvert decreases. Figures 6-7 The growth relationship between PZP, XPZ and the assembly evaluation index PP is reflected and fitted into a curve. The larger the value of the box culvert smoothness index XPZ, the worse the smoothness between the box culverts, and the larger the value of the assembly evaluation index PP. The larger the value of the center of gravity evaluation index PZP, the worse the center of gravity stability between the box culverts, and the larger the value of the assembly evaluation index PP. The growth relationship between the assembly center of gravity evaluation index PZP and the assembly evaluation index PP is obtained by fitting.

[0083] This invention also provides a BIM-based prefabricated box culvert assembly system for executing a BIM-based prefabricated box culvert assembly method, including:

[0084] The model building module numbers the N box culverts, and each box culvert is divided into multiple sub-modules. The point cloud data of the sub-modules is collected and imported into the 3D modeling software to generate the sub-module model.

[0085] The center of gravity analysis module is used to place the box culvert model in a three-dimensional coordinate system, perform correlation analysis on sub-modules, generate sub-module quality, perform correlation analysis on sub-module quality, generate the center of gravity coordinates of the box culvert model, perform correlation analysis on the center of gravity coordinates of the box culvert, generate the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model, and perform correlation analysis on the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model to generate the assembly center of gravity evaluation index PZP.

[0086] The flatness analysis module is used to obtain the plane coordinates of each box culvert, including the upper and lower plane coordinates. Correlation analysis is performed on the plane coordinates to generate the box culvert plane equation. Correlation analysis is then performed on the box culvert plane equation to generate the box culvert flatness index XPZ.

[0087] The output module is used to perform correlation analysis on the box culvert flatness index XPZ and the center of gravity evaluation index PZP, generate the assembly evaluation index PP, compare the assembly evaluation index PP with the threshold, and output the assembly evaluation level.

[0088] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0089] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0090] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0091] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A BIM-based prefabricated box culvert assembly method, characterized in that, The specific steps include: S1. The target box culvert is uniquely identified and coded, and the box culvert is divided into multiple sub-modules. The three-dimensional point cloud data of each sub-unit is collected and the data is stored in a structured database. The point cloud data is converted into a digital geometric model using a computer-aided design platform to generate the sub-module model. S2. Construct a unified three-dimensional spatial coordinate system, spatially locate and associate each sub-module model, calculate the mechanism based on the internal quality parameters of the model, analyze the spatial relationship and correlation between sub-modules, generate the center of gravity coordinates of the box culvert model, calculate the center of gravity offset, box culvert deviation and box culvert center of gravity height through multi-dimensional data correlation analysis, and generate the assembly center of gravity evaluation index. Perform correlation analysis on submodules to generate submodule quality. The formula used is: Among them, submodule quality The mass M of the i-th box culvert is used to reflect the mass of the j-th submodule of the i-th box culvert. i for Let be the density of the j-th submodule of the i-th box culvert; A correlation analysis was performed on the quality of the sub-modules to generate the centroid coordinates (x, y) of the i-th box culvert model. i ,y i ,z i The formula used is: in, Let be the centroid coordinates of the j-th submodule of the i-th box culvert model; For the centroid coordinates (x) of the box culvert model i ,y i ,z i Correlation analysis was performed to generate the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG, based on the following formula: Wherein, H is the height of the assembled box culvert, the box culvert deviation XPP is used to reflect the degree of deviation between other box culverts and the bottommost box culvert, and to reflect the degree of deformity of the overall shape of the box culvert, the box culvert model center of gravity offset XZP is used to reflect the degree of deviation between the comprehensive center of gravity of other box culverts and the center of gravity of the bottommost box culvert, and to reflect the stability of the center of gravity of the box culvert, and the box culvert center of gravity height XZG is used to reflect the height evaluation value of the center of gravity of the box culvert. S3. Collect spatial coordinate data of the box culvert surface, use a data association algorithm to perform plane fitting on the coordinate point set, generate the corresponding plane mathematical model, and calculate the box culvert smoothness index based on the fitting results as a quantitative evaluation of the box culvert surface smoothness. S4. Using a multivariate data fusion model, the box culvert flatness index and the assembly center of gravity evaluation index are comprehensively analyzed to generate an assembly evaluation index and determine whether the assembly requirements are met.

2. The assembly method for BIM-based prefabricated box culverts according to claim 1, characterized in that: N box culverts are numbered in ascending order. Each box culvert model is divided into M sub-modules. Point cloud data of all sub-modules are acquired using LiDAR and imported into modeling software to generate sub-module models. The volume of the j-th sub-module of the i-th box culvert is...

3. The assembly method for BIM-based prefabricated box culverts according to claim 2, characterized in that: A correlation analysis was performed on the box culvert model's center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG to generate the assembly center of gravity evaluation index PZP. The formula used is as follows: Where H is the height of the assembled box culvert, L is the length of the box culvert, and the assembly center of gravity evaluation index PZP is used to reflect the evaluation degree of the box culvert assembly in terms of the center of gravity.

4. The assembly method for BIM-based prefabricated box culverts according to claim 3, characterized in that: Let the equation of the upper plane of the i-th box culvert be: The equation of the lower plane of the i-th box culvert is: The constraints are: Construct the covariance matrix of the coordinate points on the plane of the box culvert, and obtain the eigenvalues ​​and corresponding eigenvectors of the covariance matrix. The eigenvector corresponding to the smallest eigenvalue is the plane normal vector, and the plane normal vector of the i-th box culvert is... The normal vector of the lower plane of the (i+1)th box culvert 5. The assembly method for BIM-based prefabricated box culverts according to claim 4, characterized in that: The normal vector of the upper plane of the i-th box culvert The normal vector of the lower plane of the (i+1)th box culvert Correlation analysis was performed to generate the box culvert smoothness index XPZ, based on the following formula: Among them, the box culvert flatness index XPZ is used to reflect the flatness between the contact surfaces of the box culvert.

6. The assembly method for BIM-based prefabricated box culverts according to claim 5, characterized in that: A correlation analysis was conducted on the box culvert smoothness index XPZ and the center of gravity evaluation index PZP to generate the assembly evaluation index PP. The formula used is as follows: PP=ln(1+e XPZ )*ln(1+PZP) The Assembly Evaluation Index (PP) is used to reflect the quality of assembly of box culverts from a shape perspective.

7. The assembly method for BIM-based prefabricated box culverts according to claim 6, characterized in that: The assembly evaluation index PP and the threshold When a comparison is performed, At that time, the assembly level of the output box culvert was Level II. At this level, the assembly of the box culvert was highly dangerous and did not meet the assembly requirements, necessitating redesign and adjustment. At that time, the assembly level of the output box culvert is Level 1, which meets the assembly requirements and does not require readjustment.

8. A BIM-based prefabricated box culvert assembly system, used to execute the BIM-based prefabricated box culvert assembly method as described in claim 1, characterized in that, include: The model building module is used to number N box culverts. Each box culvert is divided into multiple sub-modules. The point cloud data of the sub-modules is collected and imported into the 3D modeling software to generate the sub-module model. The center of gravity analysis module is used to place the box culvert model in a three-dimensional coordinate system, perform correlation analysis on sub-modules, generate sub-module quality, perform correlation analysis on sub-module quality, generate the center of gravity coordinates of the box culvert model, perform correlation analysis on the center of gravity coordinates of the box culvert, generate the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model, and perform correlation analysis on the center of gravity offset XZP, box culvert deviation XPP, and box culvert center of gravity height XZG of the box culvert model to generate the assembly center of gravity evaluation index PZP. The flatness analysis module is used to obtain the plane coordinates of each box culvert, including the upper and lower plane coordinates. Correlation analysis is performed on the plane coordinates to generate the box culvert plane equation. Correlation analysis is then performed on the box culvert plane equation to generate the box culvert flatness index XPZ. The output module is used to perform correlation analysis on the box culvert flatness index XPZ and the center of gravity evaluation index PZP, generate the assembly evaluation index PP, compare the assembly evaluation index PP with the threshold, and output the assembly evaluation level.

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