Modeling Geologic Profiles Incorporating Interlayer and Intralayer Variabilities

AbstractA geologic profile often is composed of multiple material zones due to complex geologic processes. Uncertainties associated with the geologic profile can be categorized into two groups: (1) intralayer variability, which refers to the variation of material properties within the same layer; and (2) interlayer variability, which refers to the uncertainties associated with the interlayer boundaries. The inter- and intralayer spatial variabilities have significant impact on the design and construction of geotechnical structures. This paper proposes an integrated random field model to characterize the inter- and intralayer spatial variabilities of multilayer geologic profiles simultaneously. A transition zone is used to describe the gradual transition of material properties at the interlayer boundary. The proposed model is applied to characterize the spatially variable cone tip resistance at a study site and to evaluate the effects of the integrated spatial variability of undrained shear strength on the reliability of a two-layer soil slope. Both the inter- and intralayer spatial variabilities influence the reliability of the slope. The intralayer variability is relatively more significant for the slope example in this study.