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 Lafarge
Dubie mine in Rudawa, southern Poland. The conducted tests aimed at the
determination of the geotechnical characteristics of this mixture and the evaluation
of its suitability for the construction of earth embankments, in particular road ones.
The range of the tests comprised determination of parameters characterising
physical properties, such as granulometric composition, natural moisture content,
density of solid particles, optimum moisture content and maximum dry density of
solid particles, as well as mechanical ones, like shear strength. The obtained results
show 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 compaction
when 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 of
solid 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) and
cohesion (c = 42 kPa) indicate great shear strength, therefore this soil can be
subjected to considerable mechanical stresses.