Some geomechanical properties of soil–rock mixtures in the Hutiao Gorge area, China

Abstract

Soil–rock mixtures, which are very complicated inhomogeneous materials, are widely encountered in geotechnical engineering projects. In this paper, in situ tests were performed on six samples of soil–rock mixtures in the Hutiao Gorge reservoir area to examine their mechanical characteristics. The deformation of the mixtures is closely related to the weight proportion of rock fragments and their size distribution, indicating that there may be critical fragment sizes that influence their mechanical properties, particularly cohesion. The soil–rock mixtures are sensitive to water. The results of the comparison between the tests of natural soil–rock mixtures and simulated-rain soil–rock mixtures give useful measured data for engineering evaluation and design. For natural soil–rock mixtures the cohesion c was 1·53 kPa and the internal friction angle ϕ was 46·0°; for saturated soil–rock mixtures c was 0·30 kPa and ϕ was 59·2°.