EXPERIMENTAL ANALYSIS ON THE MECHANICAL PROPERTIES OF SOIL-ROCK MIXED FILLERS WITH DIFFERENT ROCK CONTENTS ON A HIGH EMBANKMENT

Abstract

The mechanical properties of soil-rock mixed filler are the key factors influencing the high rockfill embankment stability. However, they remain unclear, given the complexity of soil-rock mixed filler structure. To analyze the stability of high rockfill embankment in the construction and operation phases, under the engineering background of a high rockfill embankment with a filling height of 50.6 m in the national highway 316 project within the Qinba mountainous area in China, a series of large-scale triaxial consolidated drained shear tests were performed on two soil-rock mixed fillers with 40% and 70% rock contents. Their stress-strain relation, deformation, and strength characteristics were observed. The applicability of Duncan-Chang model was also determined on the basis of the above tests. Results demonstrate that the stress-strain curve and volumetric strain of the filler with 40% rock content are strain hardening type and shear shrinkage type. The filler with 70% rock content has a weak strain softening, and its volumetric strain is first shear shrinkage and then shear dilation. The filler with 70% rock content has larger peak and critical frictional angles than the filler with 40% rock content. The tangential Poisson's ratios of the E-B and E-? models are obtained. The former can approximately reflect the volumetric strain characteristics of the filler with 40% rock content. The latter can approximately reflect those of the filler with 70% rock content. Yet, both models fail to describe the influence of confining pressure on the volumetric strain. The study results provide a reference for the stability analysis of high rockfill embankment engineering and provide parameters for constructing the constitutive model of soil-rock mixed fillers. Keywords: high embankment; soil-rock mixed filler; large-scale triaxial shear test; deformation characteristics; Duncan-Chang model