Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

Ten drained cyclic strain-controlled direct simple shear tests were conducted on compacted low-plasticity clayey sand to measure its cyclic compression properties. The soil had 37 % fines, liquid limit of 28% and plasticity index 14. The relative compaction of specimens prior to consolidation and cyclic shearing was between 80 and 90 %. Cyclic compression is expressed as the accumulation of vertical strain with the number of cycles, N. Vertical strain recorded at the end of every cycle, ενc, increased with the cyclic shear strain amplitude, γc, and N. Such behavior is typical and has been obtained by others on other types of soils. Amplitude γc was relatively small, ranging between 0.008% and 0.24%. Such small cyclic strains are common in moderate and large earthquakes. The effects of the dry unit weight, γd, and corresponding void ratio, e, vertical consolidation stress, σνc, and certain aspects of the degree of saturation, S, on ενc are evaluated. The test results revealed that for the applied conditions ενc increases with σνc and e (decreases with γd) and is smaller if S is increased above approximately 90%. For this soil the cyclic threshold shear strain of about 0.02% was obtained. Simple mechanisms that most likely govern the cyclic compression of compacted soils are discussed.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Cyclic Compression of Compacted Clayey Sand at Small Cyclic Strains

San Diego, California

Ten drained cyclic strain-controlled direct simple shear tests were conducted on compacted low-plasticity clayey sand to measure its cyclic compression properties. The soil had 37 % fines, liquid limit of 28% and plasticity index 14. The relative compaction of specimens prior to consolidation and cyclic shearing was between 80 and 90 %. Cyclic compression is expressed as the accumulation of vertical strain with the number of cycles, N. Vertical strain recorded at the end of every cycle, ενc, increased with the cyclic shear strain amplitude, γc, and N. Such behavior is typical and has been obtained by others on other types of soils. Amplitude γc was relatively small, ranging between 0.008% and 0.24%. Such small cyclic strains are common in moderate and large earthquakes. The effects of the dry unit weight, γd, and corresponding void ratio, e, vertical consolidation stress, σνc, and certain aspects of the degree of saturation, S, on ενc are evaluated. The test results revealed that for the applied conditions ενc increases with σνc and e (decreases with γd) and is smaller if S is increased above approximately 90%. For this soil the cyclic threshold shear strain of about 0.02% was obtained. Simple mechanisms that most likely govern the cyclic compression of compacted soils are discussed.