Analysis of the vane test considering size and time effects

An analysis of the vane test using an Arbitrary Lagrangian-Eulerian formula tion within a finite element framework is presented. This is suitable for s oft clays for which the test is commonly used to measure in situ undrained shear strength. Constitutive laws are expressed in terms of sheer stress-sh ear strain rates, and that permits the study of time effects in a natural m anner. An analysis of the shear stress distributions on the failure surface according to the material model is presented. The effect of the constituti ve law on the shear band amplitude and on the position of the failure surfa ce is shown. In general, the failure surface is found at 1-101 times the va ne radius, which is consistent with some experimental results. The problem depends on two dimensionless parameters that represent inertial and viscous forces. For usual vane tests, viscous forces are predominant, and the meas ured shear strength depends mainly on the angular velocity applied. That ca n explain some of the comparisons reported when using different vane sizes. Finally, the range of the shear strain rate applied to the soil is shown t o be fundamental when comparing experimental results from vane, triaxial an d viscosimeter tests. Appart from that, an experimental relation between un drained shear strength and vane angular velocity has been reproduced by thi s simulation. Copyright (C) 1999 John Wiley & Sons, Ltd.