Geotechnical and Geological Engineering

, Volume 31, Issue 1, pp 279–296

Laboratory Investigation into the Effects of Silty Fines on Liquefaction Susceptibility of Chlef (Algeria) Sandy Soils

  • Hanifi Missoum
  • Mostefa Belkhatir
  • Karim Bendani
  • Mustapha Maliki
Original paper

DOI: 10.1007/s10706-012-9590-6

Cite this article as:
Missoum, H., Belkhatir, M., Bendani, K. et al. Geotech Geol Eng (2013) 31: 279. doi:10.1007/s10706-012-9590-6

Abstract

In a number of recent case studies, the liquefaction of silty sands has been reported. To investigate the undrained shear and deformation behaviour of Chlef sand–silt mixtures, a series of monotonic and stress-controlled cyclic triaxial tests were conducted on sand encountered at the site. The aim of this laboratory investigation is to study the influence of silt contents, expressed by means of the equivalent void ratio on undrained residual shear strength of loose, medium dense and dense sand–silt mixtures under monotonic loading and liquefaction potential under cyclic loading. After an earthquake event, the prediction of the post-liquefaction strength is becoming a challenging task in order to ensure the stability of different types of earth structures. Thus, the choice of the appropriate undrained residual shear strength of silty sandy soils that are prone to liquefaction to be used in engineering practice design should be established. To achieve this, a series of undrained triaxial tests were conducted on reconstituted saturated silty sand samples with different fines contents ranging from 0 to 40 %. In all tests, the confining pressure was held constant at 100 kPa. From the experimental results obtained, it is clear that the global void ratio cannot be used as a state parameter and may not characterize the actual behaviour of the soil as well. The equivalent void ratio expressing the fine particles participation in soil strength is then introduced. A linear relationship between the undrained shear residual shear strength and the equivalent void ratio has been obtained for the studied range of the fines contents. Cyclic test results confirm that the increase in the equivalent void ratio and the fines content accelerates the liquefaction phenomenon for the studied stress ratio and the liquefaction resistance decreases with the increase in either the equivalent void ratio or the loading amplitude level. These cyclic tests results confirm the obtained monotonic tests results.

Keywords

SiltSandLiquefactionShear strengthVoid ratio

List of symbols

CLR

Cyclic liquefaction resistance

CSR

Cyclic stress ratio

Cu

Coefficient of uniformity

Dr

Initial relative density

e

Global void ratio

emax

Maximum void ratio

emin

Minimum void ratio

es

Inter-granular void ratio

e*

Equivalent void ratio

Fc

Fines content

Gs

Specific gravity of soil grain

Nc

Number of cycles

p

Effective mean stress

ps

Effective mean stress at steady state

q

Deviatoric stress

qm

Loading amplitude

qs

Deviatoric stress at steady state

Sus

Undrained residual shear strength

εa

Axial strain

\( \phi_{s} \)

Mobilized angle of inter-particle friction at steady state

\( \gamma_{d} \)

Solid dry density

\( \sigma_{c} \)

Confining pressure

Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Hanifi Missoum
    • 1
  • Mostefa Belkhatir
    • 2
  • Karim Bendani
    • 1
  • Mustapha Maliki
    • 1
  1. 1.Laboratory of Construction, Transports and Environment Protection (LCTPE)University of MostaganemMostaganemAlgeria
  2. 2.Laboratory of Materials Sciences and EnvironmentUniversity of ChlefChlefAlgeria