Shear Strength and Microscopic Behavior of Micaceous Kutch Soil

Micaceous soils are generally known for their high compressibility and low compacted density behavior. Mica particles have an influence on the compaction properties of soil due to their platy shape, ability to split into very thin flakes and the inter-space within the thin flakes. The mica flakes also impart resilience to the soil, which makes it difficult to compact. The spring nature of mica flakes helps them to recover their shape, when the stress is removed. The presence of mica particles in noncohesive (sandy/silty) soil affects its grain packing. The particles of non-cohesive soils (sand, silt) are predominantly rounded particles, and the presence of mica in such soils tends to decrease the packing efficiency by increasing the size of void space within the soil mass. Mica flakes alter the packing of rounded particles (silt, sand) through bridging & ordering effects at significant percentage of mica content in soils. If mica content in soil is more than ۱۰%, it has strong impact on compressibility, compressive strength and volume stability of micaceous soil. The current research is focused on the effect of water content on shear strength behavior of naturally available micaceous silty soil (Kutch, Gujarat). The resilience behavior of mica particles and the presence of water molecules in the inter-space of mica thin flakes were studied to understand the variation in shear strength behavior of micaceous Kutch soil (۱۴% mica) due to the change in its water content. A series of shear strength tests were performed on micaceous Kutch soil at different water content varying from ۰% to ۲۳.۵%. A series of XRD, SEM and AFM tests were also performed on Kutch soil to determine the mica content and understand the size, shape and geometric arrangement of particles (mica, silt, sand) within the soil mass.

Keywords:

Mica , Shear strength , XRD , SEM , AFM , Micaceous soil