Probability of Detecting Underground Anomalies from Boreholes

The uncertainties in the determination of the actual site conditions in a Geotechnical. project continues to be a dominant problem for the Geomechanics profession. These uncertainties are considerable enough even in naturally occurring deposits, with nominally homogeneous soils. However, the problem takes on an added complication when the deposit contains unusual intrusions, anomalies or discontinuities, whether these be natural or man-made. In these cases, the uncertainties considerably increase, and the Geotechnical Engineer is placed at a distinct disadvantage.

This paper outlines some experiences with the use of simple probability in attempting to quantify the level of uncertainty in predicting the presence of anomalies in a site investigation. As well, several case examples are discussed.