Advanced Soil Testing Laboratories
A cluster of advanced soil testing
equipment is maintained by the geotechnical group at the University of
Colorado at Boulder. These facilities are particularly suitable for experimental research
involving advanced modeling of the constitutive behavior of soils. The laboratories
contain several cubical cells which can be subjected to static or cyclic loading under
proportional or nonproportional loading. The laboratories also contain a large-scale
directional shear apparatus, advanced triaxial testing machines, a resonant column device,
and equipment designed for triaxial testing at low confining pressures. The facilities
also include several universal testing machines for tension and compression testing of
geological materials including three load frame with capacities ranging from 110,000 to
1,000,000 lbs. |
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Several cubical cell devices are available for soil, rock, and concrete
testing. The versatility of a cubical cell apparatus is such that the three applied
pressures can be individually controlled to follow any stress path in three-dimensional
principal stress space. Normal displacements on all six faces of the cubical soil
specimens and pore pressure inside and on the face of the specimen can be measured. It is
possible to conduct both stress and strain controlled tests as well as experiments with
cyclic loading. The high pressure cubical cell is also equipped with facilities to conduct
tensile loading in all three directions simultaneously.
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The large-scale directional shear cell is an unconventional device used to
test the response of soils under highly nonproportional, cyclic loading where the
principal stress magnitudes and directions are allowed to vary and rotate arbitrarily to
simulate real behavior while displacements of the specimen are measured. It has been
found that significant changes in the
soil's deformation characteristics take place, changes which cannot be uncovered in
traditional testing techniques.
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