• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.25-35
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• 2008

It has been recognized that the behaviour of unsaturated soil plays an important role in geomechanics. However, up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. From the test results, the behaviours of wetting-induced collapses are observed during the drainage/water absorption tests. Under exhausted-drained conditions during shearing, the shear strength increases with an increasing initial suction. On the other hand, the volume changes become small with an increase in the initial suction. And, the volumetric strain during shearing is independent of the confining pressure.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.998-1003
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• 2008

It has been recognized unsaturated soil behaviour playing an important role in geomechanics. Up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter (i.e. non-contactable transducer) during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. Various triaxial compression tests for unsaturated soil under different drainage conditions are carried out. The behaviour of the pore pressure, namely, the pore-air pressure and the pore-water pressure, and matric suction during the shearing tests are investigated. The experimental results have revealed that the mechanical behaviour of unsaturated soil can be significantly affected by the matric suction.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1224-1227
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• 2006

It has been recognized unsaturated soil behaviour playing an important role in geomechanics. Up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter (i.e. non-contactable transducer) during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. The measurement of volume changes were performed with 0.5% of the maximum error under the axial strain ratio of less than 10%. The experimental results have revealed that the mechanical behaviour of unsaturated soil can be significantly affected by the matric suction. During the shearing processes, the level of maximum deviator stress under the initial suction pressure of 50kPa was higher than that under the initial suction pressure of 10kPa. On the other hand, the volume changes became smaller under the increase in the initial suction pressure.