Geomechanics and Engineering

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Shear infiltration and constant water content tests on unsaturated soils

  • Rasool, Ali Murtaza (National Engineering Services Pakistan (NESPAK)) ;
  • Aziz, Mubashir (Department of Civil Engineering, National University of Computer and Emerging Sciences (NUCES))
  • Received : 2019.09.21
  • Accepted : 2019.11.27
  • Published : 2019.12.10
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Abstract

A series of element tests with different drainage conditions and strain rates were performed on compacted unsaturated non-plastic silt in unconfined conditions. Soil samples were compacted at water contents from dry to wet of optimum with the degree of saturation varying from 24 to 59.5% while maintaining the degree of compaction at 80%. The tests performed were shear infiltration tests in which specimens had constant net confining pressure, pore air pressure was kept drained and constant, just before the shear process pore water pressure was increased (and kept constant afterwards) to decrease matric suction and to start water infiltration. In constant water content tests, specimens had constant net confining pressure, pore air pressure was kept drained and constant whereas pore water pressure was kept undrained. As a result, the matric suction varied with increase in axial strain throughout the shearing process. In both cases, maximum shear strength was obtained for specimens prepared on dry side of optimum moisture content. Moreover, the gradient of stress path was not affected under different strain rates whereas the intercept of failure was changed due to the drainage conditions implied in this study.

Keywords

Acknowledgement

Supported by : The Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT)

The Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) is gratefully acknowledged for research facilities and financial assistance.

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