Location

St. Louis, Missouri

Session Start Date

4-26-1981

Session End Date

5-3-1981

Abstract

Stress-controlled cyclic triaxial tests were performed on clay samples obtained from the subgrades of existing highway pavements in the State of Michigan. These samples were unconsolidated or isotropically consolidated and then tested under the following conditions: 1) confining pressures of 34.5 psi and 172.4 kPa (5 and 25 psi), 2) a range of stress ratio from 2 to 4, 3) a constant frequency of one cycle per second, and 4) at the natural water contents. Test equipment included an MTS electrohydraulic closed-1oop system which applies the sustained and cyclic loads to the sample in a stress-controlled mode, a minicomputer which controls the actuator of the MTS system to yield a loading function similar to that applied, by tandem axle truck, to the pavement section, and measuring devices including two vertical and two radial LVDT(s), a load cell, a pore water pressure transducer, recording devices and an ascilloscope. The test results indicate that, for all samples, the plastic strain rate (in the logarithmic mode) assumes two values per test. The first of these values is constant from cycle number one to cycle number 100 while the second value is also constant and it controls the plastic strain beyond cycle number 100. This abrupt change in the strain rate values was observed in the unconsolidated and consolidated samples. Also, it was found that the ultimate stress ratio that it can be applied on the sample during cyclic loading is a function of the confining pressures and other sample parameters.

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

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

Soil Behavior Under Dynamic Loadings

St. Louis, Missouri

Stress-controlled cyclic triaxial tests were performed on clay samples obtained from the subgrades of existing highway pavements in the State of Michigan. These samples were unconsolidated or isotropically consolidated and then tested under the following conditions: 1) confining pressures of 34.5 psi and 172.4 kPa (5 and 25 psi), 2) a range of stress ratio from 2 to 4, 3) a constant frequency of one cycle per second, and 4) at the natural water contents. Test equipment included an MTS electrohydraulic closed-1oop system which applies the sustained and cyclic loads to the sample in a stress-controlled mode, a minicomputer which controls the actuator of the MTS system to yield a loading function similar to that applied, by tandem axle truck, to the pavement section, and measuring devices including two vertical and two radial LVDT(s), a load cell, a pore water pressure transducer, recording devices and an ascilloscope. The test results indicate that, for all samples, the plastic strain rate (in the logarithmic mode) assumes two values per test. The first of these values is constant from cycle number one to cycle number 100 while the second value is also constant and it controls the plastic strain beyond cycle number 100. This abrupt change in the strain rate values was observed in the unconsolidated and consolidated samples. Also, it was found that the ultimate stress ratio that it can be applied on the sample during cyclic loading is a function of the confining pressures and other sample parameters.