Lisa,
There is very little information available on the topic of large scale shear
testing. The Large Displacement Shear Box (LDSB) here at Virginia Tech is used
for testing 0.7 m x 0.4 m interfaces with maximum displacements of 0.3m.
Clay/HDPE geomembrane and geomembrane/Geotextile interfaces have been tested
using the LDSB. Recently, a large testing program on soil/concrete interfaces
was completed.
There are many issues concerning the design of a 3m x 3m shear box, and
some of
them are not ever considered in smaller boxes. One issue of importance I can
think of is compliance. Interfaces are very sensitive to small displacements.
Therefore, equipment compliance (deflections) must be carefully accounted for
in a shear box of this size. This is only to point out that it is not possible
to extrapolate the design from smaller boxes (< 1m x 1m) to a 3m x 3m box.
For details on the LDSB and references, check:
Gómez, J.E., Filz, G.M., and Ebeling, R. M. (1999). “Development of an
improved
numerical model for concrete-to-soil interfaces in soil-structure interaction
analyses,” Technical Report ITL-99-1, U.S. Army Engineer Waterways Experiment
Station, Vicksburg, MS. Available online at
http://www.wes.army.mil/ITL/itlpubl.html
and also:
Shallenberger, W.C., and Filz, G.M. (1996). “Interface strength determination
using a large displacement shear box,” Proceedings of the Second International
Congress on Environmental Geotechnics, Osaka, Japan.
and
CU type interface tests are described in:
Gomez, J.E., and Filz, G.M. (1999)."Effects of consolidation on the
strength of
the interface between a clay liner and a smooth geomembrane". Conference
Proceedings, Geosynthetics '99. pp., 681
Hope this helps. I'll be glad to help in any way I can, so please contact
me if
you need more information.
Jesus Gomez
Virginia Tech
>Dear list members,
>
>Hi, my name is Lisa Robinson and I am an Australian engineering student
>currently studying in Germany.
>At the moment I am working in the goetechnical labs of my host uni, and
>assisting in the preliminary research regarding the testing of shear
>strength of large-sized granular soils and/or geotextiles.
>We are hoping to develop a large scale (up to 3m) direct shear box test
>procedure. If anyone can point me in the direction of any references, papers
>or websites relating to this topic it would be much appreciated.
>Thankyou in advance,
>Regards
>Lisa Robinson
>
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