Strength and Deformation Properties of Earth-Rock Mixtures

摘要

Results and analyses of a series of strain-controlled, consolidated-undrained and unconsolidated-undrained triaxial compression tests performed on various gradations of artificially blended earth-rock mixtures and on a natural earth-rock mixture associated with the construction of DeGray Dam, Caddo River, Arkansas, are presented. It was shown that R triaxial tests on scalped/replaced gradations of a soil-rock mixture may yield substantially overconservative estimates of the strength of the full-scale material depending on the gravel content and plasticity of the fine fraction. On the other hand, Q tests on scalped/replaced specimens may over-estimate the strength of the full-scale gradation. It is recommended that triaxial testing of earth-rock mixtures be performed on the full-scale material (large specimens) or at least on the altered gradation obtained by removing (scalping) no more than 10% by weight of the full-scale material's largest particles. While this investigation did not seek to determine the effects on strength-deformation behavior of earth-rock mixtures of plasticity of the fines. Test results suggest that plasticity of the fines influences the differences seen between strengths of full-scale material as compared to scalped/replaced material.