A classification of weak rocks for their use in road embankments

Abstract

Weak or soft rocks are defined as those materials whose geomechanical behavior is between hard rocks and soils. According to Giambastiani (2014), weak rocks are classified as i) primary detrital, metamorphic or volcanic rocks; and ii) secondary or evolving rocks, after the physical-chemical alteration of former hard rocks. Furthermore, weak rocks are critical geological materials since they may present undesirable behaviors, such disaggregation, fissures by cracking, crumbling, low strength and stiffness, high plasticity, slaking, fast weathering, and irreversible volume, textural and mineralogical changes (e.g., Alonso and Alcoverro, 2004).