Deformation Characteristics of Granular Materials Under Hydrostatic Compression

Abstract

The deformation characteristics of sand and other granular materials under hydrostatic compression are studied in the conventional triaxial apparatus using 4 × 4 in. (10 × 10 cm) specimens. Modifications have been made for measuring small axial strains and free end platens were used. The errors in testing have been estimated and their effect was evaluated. Different kinds of granular materials were tested to study the effect of the physical properties of the material on its deformational behavior.The results showed that the total deformation of a mass of sand subjected to a hydrostatic compression is generally not recoverable, and can be divided into elastic (recoverable) and sliding (irrecoverable) components. It has also been found out that for a dense specimen of sand most of the total deformation is recoverable, since the sliding component of deformation represents only a small fraction of the total deformation. The results also showed that for the very dense specimen axial and radial strains were nearly equal which implies that the material behaves isotropically. On the other hand for a loose specimen the sliding component of deformation becomes large and thus the total deformation of the specimen cannot be considered completely elastic. Furthermore axial and radial strains of the loose specimen were not equal.

Discussion: Some deviations for isotropy in a lightly overconsolidated clay

“…Regarding anisotropy in strains during isotropic compression, it must be pointed out that Mitchell's observation of greater axial strain than radial strain for the vertical specimen (and vice versa for the horizontal specimen) is in disagreement with the observations of Khera and Krizek (1968) and Lewis (1972) for clays and Gerrard (1967) and El-Sohby and Andrawes (1972) for sands. This contradiction needs closer examination and raises a doubt as to whether such deviations from isotropy are a result of preferred particle orientation or the anisotropic in situ stress at the end of consolidation or both.…”

Geotechnical Characteristics of Volcanic Beach Sands with Varying Iron Contents

“…The deformation of granular materials has two subsets: the recoverable deformation caused by elastic deformation of the individual particles and the irrecoverable, or plastic, deformation because of the sliding or slipping of particles relative to each other, which results in permanent fabric change of the soil (El-sohby and Andrawes 1972;Hardin and Blandford 1989;Choo and Burns 2014). Therefore, the deformation=compressibility of granular materials is affected by various parameters such as void ratio, roundness, roughness, uniformity coefficient, mineralogy, and stress history, etc.…”

Dynamic penetration resistance and the prediction of the compressibility of a fine-grained sand—a laboratory study

“…The other factors identified above have been studied by a number of workers (e.g. Schultze & Moussa, 1961;Chaplin, 1963;Makhlouf & Stewart, 1965;Koerner, 1968;Rowe, 1970Rowe, ,1972El-Sohby & Andrawes, 1972;Holubec & D'Appolonia, 1973;Cornforth, 1974;Dahlberg, 1975;Lade & Duncan, 1976;Seed, 1976;Daramola, 1978;Lambrechts & Leonards, 1978). The influence and probable importance of each factor are given in Table 2.…”

“…After consolidation through a drained stress path, a 20 mm dia. 60" cone-ended penetrometer was driven into the top of the specimen, by repeated (1975) Karst et al (1965). Lambrechis & Gonards (1978), Daramola (1978), Sutton (1979) Daramola (1978) CLAYTON, HAEMESA AND SMONS In the second phase of testing, a large number of stress path tests were carried out under computer control in a Bishop-Wesley cell (Bishop & Wesley, 1975), following the stress paths used in the large triaxial cell.…”