Optimal Site Investigation Through Combined Geological and Property Uncertainties Analysis

Abstract

Site investigation is crucial in character- izing the geomaterial profile for the design of bridge pile foundations. A site investigation plan should be conducted to maximize geomaterial information and minimize uncertainty. Thus, both geological and property uncertainties should be explicitly incorpo- rated into a site investigation plan. This leads to the question of how to choose the corresponding optimal number and location of boreholes in a multiphase site investigation plan in order to reduce these uncer- tainties. This study addresses these problems using multinomial categorical prediction and universal kriging on a random field with multiple simulations. Site investigation data for this study are taken from a bridge project in Iowa, USA, which consists of four boreholes, each within the proximity of the pile foundation location. Subsequent numbers of recom- mended boreholes and their associated locations are determined to minimize the combined uncertain- ties. The effectiveness of this combined analysis for determining an optimal site investigation plan (OSIP) is validated and compared to an analysis done solely on property uncertainty. The proposed OSIP yields a lower prediction error, improves the prediction of geomaterial type and property, and reduces the sub- surface uncertainties. The incorporation of OSIP invariably improves the design efficiency and perfor- mance of bridge pile foundations