Development of a 3D GIS database model for geotechnical analysis incorporating geostatistics

Abstract

The application of 3D GIS and geostatistical tools in geotechnical fields enables geotechnical engineers to think spatially and make decision wisely. To support the 3D GIS applications, geotechnical data need to be managed based on their spatial components. The objective of this study is to develop a new geotechnical database model supporting the spatial analysis requirement of a 3D GIS. The result of this study will provide a foundation for the future development of a 3D GIS geotechnical database for Singapore Island. A data requirement analysis has been conducted and based on the data requirements the new geotechnical database model is developed as a hybrid database model inheriting the advantage of existing geotechnical and geological models. The developed geotechnical database model combines the rational worldview of NADM model (North American Geologic-map Data Model), the rigorous data structure of the AGS format, and the flexibility of the XML schema. The proposed geotechnical database model highlights the existence of different interpolation results based on the same entities by decoupling the geotechnical test data from the stratigraphy schema. It enables the geotechnical test data to be fitted into various stratigraphy schemas without any constraints. To handle the subsurface stratigraphy data, an XML schema is developed for the hybrid database model. Using the XML support from the database industry, the complex relationships interpolated for different soil subsurface can be stored in an XML database and retrieved for reuse. Rather than breaking the stratigraphy information into different segments just for storage purposes without any geotechnical meanings, XML database can manage stratigraphy data as an integrated unit. Meanwhile, an XML schema for the variogram model is also proposed. By taking advantage of an XML database, the variogram for soil properties can be efficiently viii