Location

St. Louis, Missouri

Session Start Date

4-2-1995

Session End Date

4-7-1995

Abstract

A cyclic torsional shear testing system was developed to measure the dynamic properties of soils at a wide range of strain levels (10-4 ~ 1%). Use of proximity transducer and pneumatic actuator in a closed loop system enabled us to measure the deformation at very small strains. A new simple nonlinear model of G/Gmax = 1/(α+γβ) agreed well with the test results of various geologic materials. In this model, parameter a represents the strain at which the stiffness starts to decrease, and parameter α controls the rate of the stiffness degradation. Loose sands had larger α and β, whereas clays and mudstones had smaller α and β. A unique relationship of β = 0.2logα + 0.3 was also found from the compiled data.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Third Conference

Publisher

University of Missouri--Rolla

Publication Date

4-2-1995

Document Version

Final Version

Rights

© 1995 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 2nd, 12:00 AM Apr 7th, 12:00 AM

Nonlinear Cyclic Stress-Strain Relations of Soils

St. Louis, Missouri

A cyclic torsional shear testing system was developed to measure the dynamic properties of soils at a wide range of strain levels (10-4 ~ 1%). Use of proximity transducer and pneumatic actuator in a closed loop system enabled us to measure the deformation at very small strains. A new simple nonlinear model of G/Gmax = 1/(α+γβ) agreed well with the test results of various geologic materials. In this model, parameter a represents the strain at which the stiffness starts to decrease, and parameter α controls the rate of the stiffness degradation. Loose sands had larger α and β, whereas clays and mudstones had smaller α and β. A unique relationship of β = 0.2logα + 0.3 was also found from the compiled data.