A GEOTECHNICAL ASSESSMENT OF USABILITY OF A ROCKSOIL MIXTURE FOR EARTH STRUCTURES

Abstract

The subject-matter of the work is a mixture of rock and soil from the LafargeDubie mine in Rudawa, southern Poland. The conducted tests aimed at thedetermination of the geotechnical characteristics of this mixture and the evaluationof its suitability for the construction of earth embankments, in particular road ones.The range of the tests comprised determination of parameters characterisingphysical properties, such as granulometric composition, natural moisture content,density of solid particles, optimum moisture content and maximum dry density ofsolid particles, as well as mechanical ones, like shear strength. The obtained resultsshow that the tested mixture is suitable for the construction of road embankments,since as coarse-grained soil, it has a high value of the uniformity coefficient (Cu =1913). Therefore, this is very well graded soil, which provides a good compactionwhen it is built into the embankment. The natural moisture content (on average wn= 9.5%) is close to the optimum one (wopt = 8.5%). The maximum dry density ofsolid particles (ds = 2.16 gcm-3) is much higher than the minimum required (d ≥1.6 gcm-3). The values of the angle of internal friction (on average  = 36) andcohesion (c = 42 kPa) indicate great shear strength, therefore this soil can besubjected to considerable mechanical stresses.