Quasi-Elastic Deformation Properties of Toyoura Sand in Cyclic Triaxial and Torsional Loadings

Abstract

Quasi-elastic deformation properties of dry, dense Toyoura sand at very small strain level were investigated by conducting a series of triaxial and torsional shear tests on hollow cylindrical specimens. Strains were measured locally by a newly developed pin-typed local deformation transducer. In the tests, effect of end-restraint at the top cap and pedestal on small strain shear modulus that was measured externally by applying small unload /reload cycles in the torsional direction was found to be significant. A new hypoelastic model was proposed to simulate the inherent and stress-induced anisotropies of quasi-elastic deformation properties of sand, considering rotation of principal stress axes from material axes. Good agreements between experimental and simulation data were observed. In the simulation, effect of inherent anisotropy on the quasi-elastic deformation properties of Toyoura sand was found to be small.

Hyperelastic modelling of small‐strain stiffness anisotropy of cyclically loaded sand

“…In contrast with the simulations conducted by Gajo and Bigoni [13], which were obtained considering two monotonic torsional shear tests, the results shown in Figure 12 were deduced by strictly simulating the cyclic torsional shear tests performed by HongNam and Koseki [43]. The less accurately simulated compliance term is M 44 , although even in this case the inconsistency is negligible.…”

“…The last comparison drawn with experimental measurements is shown in Figure 12 and concerns cyclic torsional shear tests performed by HongNam and Koseki [43] on dense Toyura sand (with an initial void ratio between 0.70 and 0.74) in a hollow cylinder apparatus under an initial confining pressure of 100 kPa. Local strain measurements were taken with inner and outer horizontal LDT transducers and with two outer sets of LDT transducers placed along the side of a right-angle triangle (so that the first LDT is horizontal, the second is vertical and the third is oblique).…”

A model for stress and plastic strain induced nonlinear, hyperelastic anisotropy in soils

“…More recently, Hong Nam and Koseki [49] measured the evolution of elastic stiffness in torsional loading tests performed in a hollow cylinder apparatus, involving a rotation of principal stress axes. Even in this case, a power law dependency of the elastic properties in the direction of principal stress axes versus principal stresses has been proposed to interpolate the experimental measurements.…”

Static and dynamic evaluation of elastic properties of Sofia sand and Toyoura sand by sophisticated triaxial tests

“…5c); 4) Negative pressure of -30 kPa is applied so that the membrane is vacuumed to the mold. 5) Since the used material is sandy soil (cohesionless) the "air-pluviation" technique [9] has been adopted for the specimen preparation. It is possible to create a very uniform specimen of dry poorly graded coarse-grained soils through slow pluviation.…”