| With the development of road non-destructive testing technology(NDT),to integrate and analyze pavement distress information inspected by NDT and build a distress digital twin model,this study proposed a new building information modeling and geographic information system(BIM + GIS)framework for pavement distress integration and modeling.In addition,WebGL technology was used to effectively connect the compressed and optimized BIM distress model with the web-side collaborative management platform through lightweight methods,to expand the practical application of distress model for maintenance.The main content of this dissertation is:In this framework,surface and contour fitting methods were developed for modeling different types of surface distress.Compared with traditional 2D picture patching or 3D fixed parameter modeling methods,the proposed method achieves the 3D modeling of distress.Another part of the framework proposes a 3D modeling method for concealed distress in the pavement structure.Compared with traditional analysis and modeling methods,the proposed method transforms ground penetrating radar(GPR)data into distress models,efficiently integrates the model with the BIM platform,and improves the practical application of GPR data for road pavements.Based on the distress characteristics of two GPR images,the 3D reconstruction of suspected and local key areas of concealed distresses were identified and extracted.By automatically constructing a digital twin model including global distresses,which integrated the NDT data efficiently and transformed the distress in the virtual space.A heat map was drawn by GIS to feedback distress distribution and development and guide maintenance management.The modeling accuracy test results show that the framework can complete the 3D digital transformation of full-field distresses.The modeling accuracies of the crack and pothole models were 80.13% and 98.17%,respectively.The model of road internal distress was compared with on-site coring to determine the position and type of distress accurately.For the BIM distress database,the logic of road distress classification and grading was expounded,and the pavement class coding was further extended on the basis of the specification,and the coding of the distress including classification,name,damage degree,cause of formation and other factors is completed,ensuring the lightweight of the distress model and the consistency of information in all stages of the life cycle.Based on the identification code,a interactive plug-in between the database and the distress model is developed to realize the two-way interaction that the geometric information of the BIM distress model was transmitted to the database,and the necessary information in the database was stored in the BIM distress model.To realize the effective connection between the BIM model and the website,the format conversion and lightweight algorithm suitable for the BIM distress model were selected.After comprehensive comparison,the format adopted 3d Tiles and gl TF formats based on Json files.For the model compression algorithm,through experiments comparing the compression effects of different compression algorithms such as Draco compression and quantization compression,it was found that the compression percentage of the model using Draco and quantization compression at the same time was above 90%,and the details of the compressed distress model had no visual impact;In addition,for the model rendering optimization algorithm,the octree data storage structure and the LOD algorithm were used to improve the rendering rate,which comprehensively reduced the model rendering time to about 1/10 of the original.Finally,built a BIM-WebGL distress visualization management platform,developed the application function based on the 3D interaction of the distress model,and tested the performance of the platform to verify that the platform has good fluency and stability. |
