Investigation of small- to large-strain moduli correlations of rockfill materials — application to Romaine-2 dam

Abstract

The establishment of relationships between the shear wave velocity (Vs) and other geotechnical parameters of rockfills under large strains (e.g., oedometer-constrained modulus, Moedo, and tangent elastic modulus, Et) is a significant step toward precise modeling of earth structure stress–strain behavior. In this study, four specimens reconstituted from the rockfill used for Romaine-2 dam construction were investigated experimentally to correlate small-strain to large-strain moduli. The development of Moedoand Vswith consolidation was measured in a laboratory using the piezoelectric ring-actuator technique (P-RAT) incorporated in a large oedometer cell. A correlation between Moedoand the small-strain shear modulus (Go) was proposed. Moreover, numerical simulations were performed using the Duncan–Chang hyperbolic model to correlate Vsand the Duncan–Chang initial elastic modulus (Ei), which depends on the minor principal stress (σ3). Based on the experimental and numerical data, a relationship between the Eiand Vsof the rockfill specimens was established. Verification studies were also performed using in situ measurements obtained from the Romaine-2 dam construction, and the ability of the proposed relationships to predict Eifrom in situ Vsmeasurements was demonstrated. The proposed correlations can help geotechnical designers estimate the deformation characteristics of rockfill materials from in situ Vsmeasurements.