Finite element and empirical solutions for estimating bearing capacity and settlement of a jointed, multi-layered dam rock foundation

Abstract

Abstract: This study discusses the bearing capacity and settlement behaviour of highly jointed mica-schist rock mass that is divided into multilayers along depth beneath the foundation of Burgaz Dam in İzmir, Turkey. These layers have different geotechnical properties; hence they impose an inherent heterogeneity on the rock mass. The empirical solutions for bearing capacity based on Hoek–Brown and other rock mass parameters and pressuremeter test data were correlated with the finite element (FE) solutions. A new technique for determining the allowable and ultimate bearing capacities based on the stress–displacement curve derived from the FE shear strength reduction (SSR) method was proposed. This technique utilises the critical settlement and strength reduction factor (SRF) provided from FE–SSR. Variations in bearing capacity estimations by different solutions considering one-layered and multi-layered mediums were evaluated in detail. In addition, the amount of immediate settlement calculated from the pressuremeter test results, empirical solutions based on the one-layered and multi-layered medium, and FE model were correlated. It was determined that the settlement occurs mainly within the upper mica-schist layer. Pressuremeter tests were found to be underestimating the settlement. While the bearing capacity was not significantly changed in the multi-layered FE model as compared to the one-layered model, the amount of settlement was found to be significantly decreased to 53.7%. Highlights: Bearing capacity assessment of rock foundation based on settlement criteria was addressed.Bearing capacity and settlement of one-layered and multi-layered rock foundations were examined by empirical and numerical solutions.Finite element and empirical approaches based on laboratory and in-situ test results were compared.A novel finite element graphical approach to determine the bearing capacity of multi-layered rock was proposed.