A Comparative Study on Shear Behavior of Pure Sand and Micaceous Sand Under Undrained Monotonic and Dynamic Loading Conditions
Micaceous soils are considered undesirable for the construction of earthen structures due to low compatibility, high compressibility, and low shear strength. Mica particles are platy in nature with numerous foliated intact mica flakes. They tend to bend upon loading and rebound upon unloading caused by resilient nature. When mica particles are present with sand particles, it leads to intricate geometric assemblies such as bridging, ordering, and pore-filling phenomena. Such microstructure alters the shear behavior of micaceous sand under monotonic and dynamic loading conditions. This paper evaluates the shear behavior of micaceous sand in comparison to pure sand under monotonic and dynamic loading conditions. The results exhibited that the presence of mica deteriorated the stress–strain response of micaceous sand in comparison to pure sand during monotonic compression. It also altered the pore pressure characteristics from dilative to contractive nature. However, pure sand underwent liquefaction and the presence of mica increased the cyclic stability of micaceous sand during dynamic loading with repetitive stress reversal between compression and extension modes. The uniform sand–sand interparticle contacts might provide increased interparticle bonding in pure sand under monotonic compression, while it could be vulnerable due to loss of contacts under dynamic loading conditions. The sand–mica matrix with Bridging and Ordering effect deteriorated the monotonic shear behavior of micaceous sand, whereas it improved the dynamic behavior due to particle reorientation under repeated loading cycles.
KeywordsMica Monotonic compression Dynamic behavior Bridging-ordering Resilience
Financial Support from IIT Gandhinagar is gratefully acknowledged. Any opinions, findings, and conclusions or recommendations expressed in this material are those of authors and do not necessarily reflect the views of IIT Gandhinagar.
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