American Society of Civil Engineers


Effect of Saturation on Cyclic Volumetric Change of Compacted Silty Sands


by E. Yee, (Graduate student, Department of Civil and Environmental Engineering, University of California, Los Angeles, USA. E-mail: mailericyee@ucla.edu), P. M. Duku, (Staff Engineer, II, Fugro West Consultants, Ventura, California, USA), and J. P. Stewart, (Professor and Vice Chair, Department of Civil and Environmental Engineering, University of California, Los Angeles, USA. E-mail: jstewart@seas.ucla.edu)
Section: Part I: General Characterization and Constitutive Behavior, pp. 48-53, (doi:  http://dx.doi.org/10.1061/41103(376)7)

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Document type: Conference Proceeding Paper
Part of: Experimental and Applied Modeling of Unsaturated Soils
Abstract: Seismic compression is the accumulation of contractive volumetric strains in unsaturated soils during earthquake loading. Cyclic simple shear tests were conducted on several unsaturated soil specimens to evaluate the role of low-plasticity fines content and the degree of saturation on vertical strains from seismic compression. Sands with low plasticity fines generally show larger vertical strains than clean sands and decreased vertical strains at intermediate saturations (S ∼ 30%) relative to dry (S = 0%) and higher saturations (S ∼ 60%). At saturation levels where vertical strains are minimized, the specimens have relatively high matric suction head, which maximizes the effective confining stress in the soil sample. Accordingly, it is postulated that saturation levels that give rise to high matric suction increase the moduli of the specimen, which in turn reduces volume change susceptibility.


ASCE Subject Headings:
Compacted soils
Silts
Sand (soil type)
Volume change
Seismic effects
Compression
Earthquake loads