Soil Response to Repetitive Changes in Pore WaterPressure under Deviatoric Loading
byPark, J, Santamarina, J.C
ArticleYear:2020
Bibliography
Park, J., and Santamarina, J.C.Soil Response to Repetitive Changes in Pore-Water
Pressure under Deviatoric Loading. Journal of Geotechnical and
Geoenvironmental Engineering
Abstract
Soils often experience repetitive changes in pore water pressure. This study explores the volumetric and shear response of
contractive and dilative sand specimens subjected to repetitive changes in pore water pressure, under constant deviatoric stress in a triaxial
cell. The evolution towards a terminal void ratio eT characterizes the volumetric response. The terminal void ratio eT for pressure cycles falls
below the critical state line, between emin < eT < ecs. Very dense specimens only dilate if they reach high stress obliquity ηmax during
pressurization. The terminal void ratios for very dense and medium dense specimens do not converge to a single trend. The shear deformation
may stabilize at shakedown, or continue in ratcheting mode. The maximum stress obliquity ηmax is the best predictor of the asymptotic state;
shakedown prevails in all specimens subjected to stress obliquity ηmax < 0.95 · ηcs and ratcheting takes place when the maximum stress
obliquity approaches or exceeds ηmax ≥ 0.95 · ηcs. Volumetric and shear strains can accumulate when the strain level during pressure cycles
exceeds the volumetric threshold strain (about 5 × 10−4 in this study). A particle-level analysis of contact loss and published experimental
data show that the threshold strain increases with confinement p0
o.
Keywords
ratchetingpore water pressure cycleShakedownstress obliquityterminal void ratio