Parametric Study of Shear Behavior of Compacted Kaolinite-Bentonite

Parametric Study of Shear Behavior of Compacted Kaolinite-Bentonite–Sand Mix Proportions

Jyothi, D. N. / Prasanna, H. S. / Amrutha Lakshmi, C. V. / Nageshwar, D. K.

Fine-grained soils mainly consist of kaolinite, montmorillonite, and illite clay minerals in varying proportions along with sand and silts. The studies related to the shear behavior of such soils are being limited to the geographic locations and is having limited applications rather than the generic one. To have a thorough understanding of the general trend in variation of shear behavior of fine-grained soils having different clay mineralogical compositions around the world is tedious and time-consuming. The behavior of kaolinitic soils predominantly controlled by flocculant fabric whereas the behavior of montmorillonite soils is governed by dispersive fabric effects which also makes the study more complex. In the present experimental study, an attempt has been made, to investigate the behavior of natural fine-grained soils through a mixture of kaolinite-bentonite–sand in varying proportions. Physical properties and compaction characteristics such as MDD and OMC for Indian standard Light compaction for the mix proportions investigated were determined according to BIS specifications. The kaolinite-bentonite–sand mixture compacted at MDD and OMC was subjected to various load applied using the Box shear test and shear failure behavior was critically analyzed. Compaction characteristics of the mix proportions can be effectively correlated. The percent fines of the mix proportions have a significant bearing on the magnitude of cohesion and angle of internal friction. Useful regression models were also developed correlating shear strength behavior of the mix proportions with percent fines and sand which exhibits behavior akin to natural fine-grained soils when subjected to compactive energy.