Spatial management of geotechnical data for site selection

A ground characterisation exercise was conducted in order to identify sites suitable for a blast furnace at the Redcar steelworks in northeast England. The purpose of this exercise, conducted some 20 years after the investigations were carried out and a decade after the steelworks had been constructed, was to develop techniques for managing spatial data using Geographical Information Systems (GIS) and geostatistics. Borehole details, from the factual site investigation reports, were entered into a database using a relational structure with linked files. The borehole location and lithology files were keyed in using codes for geological material, weathering grade, strength, borehole type and verification status. Laboratory and field test data were input by scanning tables in the ground investigation reports and processing the scanned images using optical character recognition software. The XBase programming language was used to execute graphing, GIS and geostatistics programs; thereby enabling repetitive tasks to be carried out by the computer. This both saved time and reduced errors and inconsistencies that could result from repeated manual execution of the same program. Some simple spatial operations could also be carried out entirely from within dBase, an example being the use of moving-window statistics employing rectangular windows aligned parallel to the axes of the coordinate system to study local stationarity. GIS have been found to offer an effective tool for analysing, querying and presenting spatial site investigation information. Geostatistical kriging and simulation techniques offer powerful spatial modelling tools for creating visualisations of the spatial variability of parameters measured at points during a ground investigation. The Redcar case history demonstrates how a database management system (DBMS) can be used to manipulate site investigation data as part of a modelling and interpretation exercise. DBase source code allows others to follow the same path or build upon the foundations herein. © 1998 Elsevier Science B.V. All rights reserved.