Study On 3D Modeling Of Vector-grid Integration Of Chengdu Airport New City

The development and utilization of urban underground space is an important part of the current urban construction,and the 3D geological modeling of urban underground space is one of the bases to evaluate the difficulty of the development and utilization of underground space.At present,urban 3D geological modeling usually refers to building a single expression of 3D model,such as the 3D model of geological structure,geological attributes,above-ground buildings.The existing urban integrated urban modeling technology,such as the integration of the above-ground and underground or indoor and outdoor 3D models,mainly integrates the 3D models of different spatial positions.There is little research on the integration technology of different expression models in the same spatial position,especially in the integration of 3D geological structure model and 3D geological attribute model.With the help of grid subdivision and grid attribute interpolation,the integration of models and the vector grid integrated 3D geological model of "one model,multiple expressions" are constructed,which solves the problem that the geological structure and attribute are respectively expressed in the previous expression of urban underground space,which is not conducive to the comprehensive consideration of geological structure and attribute.The main achievements from the research are as following: 1)In order to get a better 3D urban geological structure model,three common modeling methods are compared from the model effect,model accuracy and modeling efficiency.The results show that the rapid modeling technology based on borehole is more suitable for the construction of the study area model in this paper.For the phenomenon that different spatial interpolation technology has different influence on the model,three common interpolation methods are compared horizontally and vertically,which show that the model obtained by Kriging interpolation technology has the advantages of high precision and high stability.2)About the urban 3D geological modeling,based on the domestic 3D geological modeling software MAPGIS 10.3,this paper summarizes the realization methods and specific processes of urban 3D geological modeling.With regard to the phenomenon of borehole stratum reversal,stratum loss and stratum duplication in the process of 3D geological structure modeling,there is a unified stratigraphic sequence method with increasing thickness of 0-layers proposed.The results show that it has a good effect in the geological structure model.The 3D geological attribute model of water content,bearing capacity and deformation modulus of Airport New City is completed by extracting the geological attribute data of borehole stratification.3)On 3D geological modeling of urban vector-grid integration,the grid transformation of the geological structure model of Airport New City is completed by regular hexahedron grid generation technology.Through the grid attribute interpolation,the geological attributes are assigned to the grid through the interpolation,and the integrated 3D geological modeling of vector grid of airport new town is completed,which realizes "one model,multiple expressions".4)This paper studies the quality evaluation method of 3D geological structure and attribute model,and evaluates the quality of 3D geological model of Airport New City.The results show that the 3D model has high precision and certain credibility.