Characteristics and Mineralogical Composition on Dynamic Soil Properties

Dynamic loads can result in damage to buildings and structures, ground cracking and slope instability. This presentation highlights the effect of plasticity characteristics and mineralogical composition on dynamic soil properties. Extensive laboratory test results show that for two materials with the same plasticity index, the cyclic resistance in soils containing montmorillonite as the clay mineral was substantially higher than the cyclic resistance in soils containing kaolinite as the clay mineral. A relationship was established between the degradation in undrained shear strength and the post-cyclic effective stress ratio (PC-ESR), which is defined as the ratio of the consolidation pressure to the effective vertical stress after cyclic loading. Additionally, relationship between the ratio of the post-cyclic undrained strength ratio with the undrained strength ratio of a normally consolidated soil and the PC-ESR was also developed. Results from natural samples agreed well with the relationships developed from the laboratory prepared mineral mixtures.

Biography:Dr. Beena Ajmera is, currently, an Assistant Professor in the Department of Civil and Environmental Engineering at California State University, Fullerton (CSUF). She has co-authored over 60 papers in various areas of geotechnical engineering including fully softened shear strength and compressibility of soil, soil modification and soil dynamics and won several prestigious fellowships including the National Science Foundation Graduate Research Fellowship, the Charles E. Via Doctoral Fellowship, the U.S. Society of Dams Scholarship, the ASCE Los Angles Group Scholarship and is a two-time recipient of the Dwight D. Eisenhower Transportation Fellowship. Dr. Ajmera has supervised or co-supervised over 30 undergraduate and graduate students on various research projects in the past two and half years. She is a member of the Earthquake Engineering and Soil Dynamics Committee and co-advisor to the Student Leadership Council of the ASCE Geo-Institute. She also serves as an editor of the journal "Landslides." She received her B.Sc. in Civil Engineering, B.A. in Applied Mathematics and M.Sc. in Civil Engineering from CSUF before obtaining her Ph.D. in Civil Engineering with focus in Geotechnical Engineering from Virginia Tech in 2015.