Abstract
Unsaturated soils are the major component of both natural and artificial earth structures, and they exhibit less predictable behavior than saturated soils. Presently, the world is experiencing pronounced impacts from climate change. Sudden heavy rainfalls and droughts both result in fluctuating soil moisture levels, meaning that soil responds differently to infrastructure loads. Accordingly, a better understanding is needed of failure causes in unsaturated soils. This research was conducted to investigate the coupled behavior of unsaturated soil with varying degrees of compaction and moisture change. Samples were prepared at 81% and 88% degrees of compaction with moisture content ranging from 10 to 25% on both sides of optimum moisture content for silty soil. Different parameters such as suction, porewater pressure, and deformation were carefully measured at every stage of the triaxial test, from sample placing to the shearing phase. The results show that there is more compressive soil behavior when there is a lower degree of compaction, i.e., 81%, along with moisture content of 15–25%. Where there is a higher degree of compaction at 88%, dilative behavior is more evident, which changes to compressive behavior as the moisture content increases. Any change in moisture content (increase or decrease) during the lifecycle of any earthen structure necessitates a long time to stabilize its suction value (decrease or increase) if it compacted to a degree that still exhibits a compressive response. This slow recovery of suction, specifically from the wetting to the drying cycle, is not favorable for soil stability upon loading.
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Data will be available if the request is made to the authors.
Abbreviations
- ε a :
-
Axial strain (%)
- u a :
-
Pore air pressure (kPa)
- u w :
-
Pore water pressure (kPa)
- σ 3 :
-
Confining pressure (kPa)
- σ d :
-
Deviatoric stress (kPa)
- ε v :
-
Volumetric strain (%)
- m.c. :
-
Moisture content (%)
- e :
-
Void ratio
- \({\gamma }_{d}\) :
-
Dry unit weight (kN/m3)
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The authors duly acknowledge the Geotechnical Engineering Laboratory at Saitama University for providing its research facilities for conducting this research.
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Ahmed, I., Shah, S.K.H., Ahmad, T. et al. Coupled Influence of Compaction and Moisture on Unsaturated Soil Response in Triaxial Tests. Geotech Geol Eng (2024). https://doi.org/10.1007/s10706-024-02807-3
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DOI: https://doi.org/10.1007/s10706-024-02807-3