Advances in GIS-Based 3-D Predictive Geotechnical Soil Model Tools

Abstract

Abstract This paper describes and illustrates recent advances in and current functionality of geographical information system (GIS)-based marine geotechnical (typically soil) model tools that are being used to predict geotechnical conditions throughout a specified 3-D space. Marine soil models are developed by integrating seismic survey and geotechnical data and then using GIS technology to efficiently manage, analyze, extract, and display predicted soil conditions. The tools described here provide geotechnical engineers, designers, and other end users with a quick and convenient way to predict general soil stratigraphy and properties at any selected location down to the depth of the model (locations are not constrained to geophysical survey lines). Specifically, a suite of customized soil model tools have been developed to provide a rapid and innovative approach to extracting, summarizing, and exporting geotechnical soils information from GIS-based 3-D soil models. Collectively, the soil model tools are referred to as the Virtual Soil Boring (VSB) tools. The VSB tools are conveniently packaged and launched from a custom toolbar installed as an add-in to a GIS map application. The VSB tools provide the user with an instantaneous means of determining geotechnical variability among user-selected locations, and provides an efficient way of exporting this information for use in complementary analyses. The VSB tools represent a major technical and efficiency advancement over the traditional "maps and 2-D profiles" method still being used by some. Importantly, the VSB tools are very user friendly and users do not have to be GIS specialists. In short, the VSB tools allow better decisions about site selection and foundation design to be made faster by end users. The GIS-based VSB tools described here are one of the most recent contributions to integrated site characterization methods that have been evolving for several decades. The VSB tools are but one aspect of the accelerating trend to provide comprehensive 3-D functionality to predictive ground (or earth) models of stratigraphy, geotechnical/earth materials, and geologic conditions. Robust 3-D predictive ground models are essential for providing reliable and comprehensive characterization and assessment of soil conditions and geohazards as a basis for optimum site selection and efficient foundation design for offshore structures.