Mutiscale 3d Geological Modeling and Geotechnical Properties Identification in Urban Geological Investigation

Abstract

The utilization of urban underground space requires an ongoing understanding of geological conditions to hone engineering decisions. Geological investigation, involving the acquisition, analysis, and visualization of geological data, plays a pivotal role in this process. To address these issues, a multigrid 3D geological modeling scheme is proposed to investigate the complex distribution of underground geological strata, and it is then employed to identify the geotechnical properties of subsoils during site investigation. Initally, multisource geological data are collected and organized, leveraging borehole and synthetic data extracted from profiles. Subsequently, 3D geological modeling is emplemented, combining discrete smooth interpolation and grid division method. Then, the geotechnical properties in different deposition ages are identified, considering the distinct characteristics of subsoil attributes among different strata. Finally, a 3D attribute model is established using indicator kriging method after the borehole density assessment with grid subdivision. Additionally, the 3D geological model can be adopted to update historical geological maps alongside the new generation of engineering site investigations, and the results of geotechnical properties analysis can also be used to explore and reconstruct potential empirical correlations for underground design, such as the relationship of the characteristic value of bearing capacity to the standard penetration test. The combination of multiple geostatistics methods and mutiscale grid scheme contribute to the 3D visualization of the complicated strata, especially in megacities with complex alluvial environment. Furthermore, identifying and categorizing the sedimentary features of subsoil properties provides valuable insights for optional designs in urban underground construction.

Keywords: Geological investigation, Urban underground space, 3D geological model, Geotechnical properties evaluation, Mutigrid method