K0-Behavior of Normally Consolidated Fine-Grained Soils during One-Dimensional Secondary Compression Aging and the Quantitative Prediction of the Quasi-Preconsolidation Effect

摘要

No consensus and little experimental evidence exist in the geotechnical engineering community regarding K(sub o)-behavior of normally consolidated fine-grained soils during one-dimensional secondary compression aging and the origin and magnitude of the quaispreconsolidation effect. After reviewing several concepts. A control volume triaxial-type test cell with support systems was developed. This equipment allows the maintenance and measurements of the K(sub o)-condition during soil consolidation. Six normally consolidated fine-grained specimens, three Edgar Plastic Kaolinite and three Agsco novaculite, were allowed to age a minimum of 14 days under a 2 tsf vertical stress while the K(sub o)-condition was maintained and measured. The specimens were loaded in small increments, following aging, to determine if the quasi-preconsolidation effect had developed. Results show K(sub o) decreases during secondary aging in one-dimensional compression for normally consolidated fine-grained soils. Moreover, the quasi-preconsolidation effect develops in both cohesive and cohesionless fine-grained soils. This suggests the quasi-preconsolidation effect develops due to increased friction rather than bonding as previously proposed. Results indicate the existing theory for predicting the magnitude of the quasi-preconsolidation effect needs further refinement.