EJGE/Magazine - Meeting Announcement

Conference Announcement

77th Meeting of the Transportation Research Board

January 1998 - Committee A2L02-Soil & Rock Properties

Call for Paper Synopses for Specialty Session on Local Strain Measurement in Laboratory Determination of Soil and Rock Stiffness.

At loading conditions insufficient to generate failure, soils and rocks often exhibit high stiffnesses and commensurately small strains. For many design conditions it is important that this low-strain behavior is accurately assessed. Examples of particular importance are in the assessment of the behavior of soil subjected to earthquake loading, behind retaining walls (and hence the load-deformation response of those walls), beneath pavements in response to traffic-induced loading and around tunnels and other excavations.

In most laboratory tests, the behavior at the soil or rock boundary is atypical of the whole specimen. For example, a triaxial specimen is artificially constrained by the end platens. This upsets the stress and hence strain field close to the loading point, leading to misleading stiffness determinations. [see, for example, paper by John Burland on "Small is Beautiful: The Stiffness of Soils at Small Strains" in the Canadian Geotechnical Journal 26 (4), November 1989, 499-516.
These two issues have led researchers and practitioners to use, increasingly, on-sample instrumentation installed away from the boundaries as a means of ensuring accurate stiffness assessments However, this leads to its own problems and uncertainties which this session of TRB will seek to address. Therefore papers are invited which will contribute to an understanding of, and best- practice in, local strain instrumentation, covering the following or related topics:

  • Reliable fixing of instruments to the specimen.
  • Effect of instrument weight on strain measurement.
  • Instrument response to loading condition (cell pressure, temperature, repeated loading, etc.)
  • Comparison of performance of different instrumentation.
  • Novel local strain instrumentation techniques.
  • Comparisons of local and off-sample measurements.
  • Assessment of boundary effects.
  • Assessment of errors and their causes in local strain measurements.
  • Calibration techniques for local strain instrumentation.
  • Assessment of improvement in soil/rock characterization due to adoption of local strain measurements.
  • Limits of strain magnitude which can be reliably measured.
  • Comparison of local and in-situ stiffness determinations.

Synopses (not more than 500 words long) of proposed papers should be by either email, fax, or regular mail to either Dr. Andrew Dawson or Prof. Paul W. Mayne not later than April 15th. Full papers will be invited in early May 1997 for those synopses offering contributions appropriate to the session's theme. Note that full papers have to be submitted to TRB for peer review, according to its normal procedures, by August 1st 1997.

It will be intended that the group of accepted papers will be published together as a Transportation Research Record, pending the TRB review process.

Dr. Andrew Dawson

Senior Lecturer
Department of Civil Engineering
University of Nottingham
Nottingham NG7 2RD England, UK
fax : (+44) 115 951-3902
e-mail: Andrew Dawson

Associate Professor Paul W. Mayne

Georgia Institute of Technology
School of Civil & Environmental Engineering
Geosystems Laboratory, 305 Ferst Drive
Atlanta, Georgia 30332-0355 USA
fax : (404) 894-2281
e-mail: Paul W. Mayne

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© Copyright Mete Oner, 1997