Location

St. Louis, Missouri

Session Start Date

4-26-1981

Session End Date

5-3-1981

Abstract

The effects of shearing strain amplitude and shearing strain rate on the shear modulus of normally consolidated specimens of San Francisco Bay Mud were studied with a specially constructed torsional shear/resonant column device. Torsional shear measurements were performed at excitation frequencies of 0.03, 0.1, 0.3, and 1.0 Hz and were followed by a resonant column measurement at the same strain amplitude. This testing sequence was conducted at constant values of shearing strain amplitude over the range from 0.001 to 0.1 percent. From these measurements the dependency of shear modulus on shearing strain rate and amplitude was studied. Shear modulus was found to increase with the logarithm of shearing strain rate at a constant shearing strain amplitude. The influence of shearing strain rate was found to be independent of shearing strain amplitude, mean effective normal stress, and duration of confinement at constant mean effective normal stress. Typical variation in shear modulus with shearing strain rate at a constant shearing strain amplitude was about four percent per log cycle of shearing strain rate. Shear modulus was found to decrease with the logarithm of shearing strain amplitude at a constant shearing strain rate. No ultimate value of shear modulus at low-amplitude shearing strains (below 0.001 percent) at a constant shearing strain rate was found. Thus, the ultimate value of low-amplitude shear modulus measured in the resonant column test is seen to be a special case in which the decrease in shear modulus due to lower shearing strain rate is counterbalanced by an increase in shear modulus due to lower shearing strain amplitude.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

4-26-1981

Document Version

Final Version

Rights

© 1981 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

COinS
 
Apr 26th, 12:00 AM May 3rd, 12:00 AM

Strain-Rate Dependent Shear Modulus of San Francisco Bay Mud

St. Louis, Missouri

The effects of shearing strain amplitude and shearing strain rate on the shear modulus of normally consolidated specimens of San Francisco Bay Mud were studied with a specially constructed torsional shear/resonant column device. Torsional shear measurements were performed at excitation frequencies of 0.03, 0.1, 0.3, and 1.0 Hz and were followed by a resonant column measurement at the same strain amplitude. This testing sequence was conducted at constant values of shearing strain amplitude over the range from 0.001 to 0.1 percent. From these measurements the dependency of shear modulus on shearing strain rate and amplitude was studied. Shear modulus was found to increase with the logarithm of shearing strain rate at a constant shearing strain amplitude. The influence of shearing strain rate was found to be independent of shearing strain amplitude, mean effective normal stress, and duration of confinement at constant mean effective normal stress. Typical variation in shear modulus with shearing strain rate at a constant shearing strain amplitude was about four percent per log cycle of shearing strain rate. Shear modulus was found to decrease with the logarithm of shearing strain amplitude at a constant shearing strain rate. No ultimate value of shear modulus at low-amplitude shearing strains (below 0.001 percent) at a constant shearing strain rate was found. Thus, the ultimate value of low-amplitude shear modulus measured in the resonant column test is seen to be a special case in which the decrease in shear modulus due to lower shearing strain rate is counterbalanced by an increase in shear modulus due to lower shearing strain amplitude.