Suitability of Engineering-Geological Environment on the Basis of Its Permeability Coefficient: Four Case Studies of Fine-Grained Soils

Abstract

The aim of the article is to compare two classifications systems of engineering-geological environment sustainability in terms of its permeability evaluated on the basis of permeability coefficient. The first evaluated classification assumes a permeable environment to be a positive characteristic in the engineering-geological assessment, while the other considers an impermeable environment as favourable. The four fine-grained soil materials were selected, as they had very similar, almost identical grains-size distribution, but different microstructure characterized by grains sphericity, angularity, and roughness. At the same time, the influence of changes in the density of soil materials (density index 10%, 30%, 60%, 90%) was analysed. Permeability coefficient was determined using six methods (empirical formulae, laboratory and microscopic analysis). The laboratory method falling head test (FHT) was taken as a reference test that reflected the actual water flow through the soil. It was found that with an increase in grain angularity and roughness (and a decrease in sphericity), the permeability coefficient was decreasing and this trend culminated along with gradual compaction. Moreover, the research shows that unsuitable methods may classify soil materials into wrong engineering-geological permeability classes, which may have negative consequences during engineering-geological or geotechnical assessment and cause subsequent problems in foundation engineering.

Stability of the Čachtice Underground Corridors

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The Characteristics of Time-Dependent Changes of Coefficient of Permeability for Superabsorbent Polymer-Soil Mixtures

“…Our model provides a simple, generally-applicable way of quantifying these effects. Despite its simplicity, it captures our measurements reasonably well; future extensions could consider variations in the porosity, sphericity, angularity, and roughness of individual SAP and soil granules, and also dynamic changes is sample height caused by absorbency under load [27], given that these parameters alone can influence the coefficient of permeability values substantially [55]…”

State of the Art on Fe Precipitation in Porous Media: Hydrogeochemical Processes and Evolving Parameters

“…Although the applicability of the Breyer equation is limited by specific porosities, it is considered most useful for granular materials with heterogeneous distributions and poorly sorted grains, particularly when C u ranges from 1 to 20, and d 10 is 0.06-0.6 mm [131]. Moreover, Marschalko et al [132] demonstrated a good agreement between the permeability calculated by the Slitcher equation and that obtained from the constant-head method for various sand. This equation is most suitable when soil particles are uniformly distributed within a range of 0.01-5 mm in particle size [133].…”