3D Mesh Model Reconstruction Method For Unfavorable Geological Structure And Its Engineering Application

In underground space exploitation,it is inevitable to encounter unfavorable geological structure and particularly important to analyze and evaluate the stability of geotechnical engineering under unfavorable geological conditions in advance.At present,using advanced computer information technology to build high-precision 3D mesh model and to analyze the 3D mesh model based on geophysical exploration data is one of the hot topics in geotechnical engineering research.In this paper,a method of reconstructing 3D mesh model for unfavorable geological structure is proposed.Firstly,the theoretical basis of 3D mesh model reconstruction is introduced.Then,the numerical simulation of elastic wave CT detection and 3D mesh model reconstruction are carried out,and the modeling accuracy of 3D mesh model reconstruction method is tested from two aspects of simulation and bearing capacity.Finally,the modeling accuracy of the 3D mesh model reconstruction method is verified by the field test of elastic wave CT detection,the stability of unfavorable geological structure and the effect of grouting reinforcement are evaluated.Theoretical research on 3D mesh model reconstruction method was based on 3D visualization and 3D mesh construction.Firstly,the advantages,disadvantages and applicability of 3D visualization modeling surface rendering and volume rendering are compared,and a 3D visualization modeling method of volume rendering based on block Kriging interpolation is proposed.In the theory of 3D mesh construction,peak method is used for material segmentation,hexahedral mesh is used as a unit for mesh generation and material attribute mapping.The cumulative labeling method for filtering outlier clusters proposed in this paper can not only improve the accuracy of modeling,but also control the size of mesh cells in the model and improve the computational efficiency.In numerical calculation,considering the different position relationship between karst cave and borehole,a 3D finite element model based on elastic wave CT detection is designed,and the results of numerical simulation are analyzed by computed tomography to obtain elastic wave CT slices.The simulation and stress-strain of the reconstructed model are compared and analyzed by using 3D mesh model reconstruction method.The results show that the simulation is 91.44% and the absolute error of volume fraction is 3.33%.The stress and strain distributions of the 3D mesh reconstruction model and the simulation model are basically the same.In view of the applicability of the 3D mesh model reconstruction method in engineering project,the elastic wave CT detection test of the karst cave of the bridge foundation of Guangzhou Tanbu Bridge was carried out.The accuracy of 3D mesh model reconstruction method is verified by drilling core.Compared with the verification holes,the simulation degree is above 85.31%,and the absolute error of volume fraction is less than 2.45%.Aiming at the stability of geotechnical engineering under unfavorable geological conditions,the elastic wave CT detection test of karst cave foundation of a super high-rise building in Wuxi was carried out.The stability and grouting reinforcement effect of super high-rise building structure foundation are evaluated.In conclusion,this method has high modeling accuracy and can accurately reflect the spatial distribution of unfavorable geology,which is of great significance to the analysis of geotechnical engineering stability under unfavorable geological conditions.