State-boundary surface for very loose sand and its practical implications

Abstract

A state-boundary surface defines a boundary in stress -void-ratio space above which no stress state can exist. The applicability of the state-boundary surface for sand has not gained widespread attention primarily because sand is not generally considered to be a difficult soil from a design point of view apart from liquefaction. Liquefaction is a phenomenon usually encountered in very loose cohesionless materials. An experimental study relating the drained and undrained behavior of very loose saturated sand is presented. It is shown that the post-peak portion of undrained stress paths travels along the state boundary and that the state boundary can be approximated by a straight line. The slope of this straight line appears to stay constant for very loose sand. There are potentially an infinite number of these lines, which form a three-dimensional surface in deviator stress -effective mean normal stress -void-ratio space. Previously published results by various researchers are used to confirm the existence of the state boundary. This surface is mathematically defined in deviator stress -effective mean normal stress -void-ratio space. Loose saturated sand samples loaded drained from a stress state on or very close to the state boundary surface essentially travel along the state boundary surface. . SUne surface d'Ctat limite d6finit une frontikre dans un espace contrainte-indice des vides au-dessus de laquelle aucun Ctat de contrainte n'existe. L'application du concept d'6tat limite aux sables n'est pas routinibre surtout parce que les sables ne sont pas considCrCs comme des sols difficiles 2 traiter d'un point de vue de conception mis 2 part les problemes de IiquCfaction. La IiquCfaction est un phCnomene qui est gCnCralement associk-aclx-matkriaux tres Iiches. Une Ctude expCrimentaie concernant le comporternent drain6 et non drain6 d h n sable saturC et tres liche est prCsentCe. I1 a Ct C montrC que les chemins de contraintes pour des conditions non-drainCes sont situCs sur la surface d'Ctat limite lorsque la rksistance au pic a Ct C mobilisCe. De plus, la surface d'6tat limite peut &tre repr6sentCe par une droite. La pente de cette droite semble &tre constante pour un sable tres Iiche. Il y a une infinit6 de droites, donc une surface tridimensionnelle dans un espace contrainte dkviatorique-contrainte principale moyenne-indice des vides. Des rCsultats publiCs par diffkrents chercheurs confirment I'existence de la surcface d'Ctat limite. Cette surface est dCfinie par une relation mathkmatique dans I'espace contrainte principale moyenne-indice des vides. Des Cchantillons liches de sable saturC dans un Ctat de contrainte sur ou 2 proximitC de la surface d7Ctat limite chargCs en conditions drainCes ont essentiellement des cheminements de contrainte sur la surface d'ktat limite.

Thermal analysis of energy piles in sand

“…Tensile stresses and strains are considered as positive in the model simulation in order to maintain consistency throughout the paper. The simulation results are in close agreement with the experimental data reported by Sasitharan et al (1994) and Carraro (2006). The values of the CASM model parameters for Ottawa sand are given in Table 1.…”

The influence of grading on the shear strength of loose sands in stress-controlled ring shear tests

“…Many have postulated that the breakdown of a metastable structure in loose soils in association with excessive volume changes during loading ultimately leads to collapse and liquefaction. Important works by Castro (1969), Casagrande (1936Casagrande ( , 1976, Seed and Idriss (1969), Bishop (1971Bishop ( , 1973, Castro and Poulos (1977), Poulos, (1981), Poulos et al (1985), Sladen et al (1985), Vaid and Chern, (1985); Alarcon-Guzman et al (1988), Negussey et al (1988), Kramer and Seed (1988), Vasquez-Herrera et al (1988), Konrad (1993), Sasitharan et al (1993), Sasitharan et al (1994), Lade and Pradel (1990), Sassa (1985Sassa ( , 2000, Sassa et al (2003), and Wang and Sassa (2002) bear witness to the extent of research and interest in soil liquefaction.…”

Evaluation of Babolsar Sand Behaviour by Using Static Triaxial Tests and Comparison with Case History

“…Chern (1983) [16], Kramer and Seed (1988) [17], Vasquez-Herrera and Dobry (1989) [18], Lade (1992) [19], (1993) [20], Ishihara (1993) [21], Konrad (1993) [22], Sasitharan et al (1993) [23], (1994) [24] and among others) identified similar yield conditions and proposed various names for these conditions. The collapse line is considered as a limit state boundary between the stable and the unstable states of soil undrained behaviour.…”