Evaluating the capability of a critical state constitutive model to predict the collapse potential of loose sand

International Symposium on Geohazards and Geomechanics 2015

地球科学;生态环境科学

Azizi, A.^1 ; Bella, G.^2 ; Farshchi, I.^3

Polytechnic University of Milan, Piazza Leonardo da Vinci, 32, Milano

20133, Italy^1

Polytechnic University of Turin, Turin, Italy^2

Linton University College, Negeri Sembilan, Malaysia^3

关键词: Collapse potential;    Consolidated undrained;    Initial void ratios;    Loose saturated sands;    Pore-water pressures;    Soil shear strength;    Static liquefaction;    Volume contraction;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/26/1/012018/pdf
DOI  :  10.1088/1755-1315/26/1/012018

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

Many catastrophic flow failures in granular soil slopes are believed to be caused by a rise in pore water pressure associated with substantial loss of soil shear strength. This failure mechanism is known as prefailure instability or static liquefaction. Constant shear (CS) and consolidated undrained (CU) triaxial tests can reproduce stress paths, in which such instability may occur before reaching the failure. In the present study, a previously proposed critical state constitutive model was first used to simulate the behavior of loose saturated sand in CU tests. It was then employed to predict the instability of loose sand subjected to the CS loading. Under such loading, loose dry sand initially experience small volume increase, and then start to contract substantially. In saturated sand, such contractions can lead to the generation of pore water pressure and sudden decrease of shear strength. The capability of the model to predict the onset of the volume contraction and collapse potential of loose dry sand was examined by comparing the model predictions with experimental results of CS tests. The comparison showed that the effect of initial void ratio, consolidation and deviatoric stresses on behavior of loose dry sand can be well predicted by the model.