My research involves experimental, theoretical and computational aspects of geomechanics in multiscale, multiphase geomaterial systems. In particular, I am interested in studying the response of geomaterials and geological systems to mechanical as well as environmental loads: such as thermal, chemical, biological, and hydrological perturbations with major implications for environmental protection and system sustainability. In the following my recent and on-going research projects are described: 

 
1) Thermo-hydro-mechanical characterization of swelling clays
 
My doctoral research at the Swiss Federal Institute of Technology at Lausanne (EPFL) integrated my interest on thermo-hydro-mechanical (THM) coupled processes and their impact on the multiscale response of the geoenvironmental systems. Using an advanced double-wall triaxial system, I investigated the impact of elevated temperatures on the mechanical response of unsaturated swelling bentonites involved in the disposal of radioactive and hazardous wastes1,2. I developed an effective technique for determination of water retention and microstructural characterization of compacted swelling clays exposed to wetting/drying as well as heating/cooling cycles3. This study improved the understanding of how the involved multiphysical processes affect the mechanical, thermal and hydraulic performance of clay barrier systems. I utilized advanced microstructural investigation techniques for 3D visualizations and characterization of the microfabric of swelling geomaterials, and showed that wetting/drying cycles can modify the microstructure permanently leading to an irreversible macroscopic behavior2,4. This study differed from long-standing assumption for an elastic and reversible microstructure of a double-structure clay system, and resulted in developing a microstructurally based constitutive model to describe the hydro-mechanical behavior of swelling clays5.
 
2) Multiscale characterization of sedimentary rocks (Opalinus shale) 
 
Being funded through a highly competitive Swiss National Science Foundation (SNSF) program, I started my work as a postdoctoral tenure at Massachusetts Institute of Technology (MIT) to study the impact of diagenesis on the pore structure and hydro-mechanical properties of shales. I developed techniques that provide quantitative information to construct multiscale models for the transport and flow analysis in sedimentary rock formations. Using the state-of-the-art equipment including Mercury Intrusion Porosimetry (MIP), BET/BJH Nitrogen Adsorption, and Scanning/Backscattered Electron Microscopy (SEM/BSEM) techniques along with high-capacity triaxial testing, I have demonstrated how the diagenetic cementation bonds modify the pore size distribution as well as the hydro-mechanical and fracture properties of shales. Furthermore, I studied the anisotropy and attenuation behavior of shales due to bedding planes and fractures using multichannel ultrasonic piezoelectric sensors8,9. In the future, I would like to study the concurrent Acoustic Emission (AE) and mechanical response of sedimentary rocks towards developing a damage-plasticity model to account for mechanical and transport properties.
 
3) Particle aggregation and transport in partially saturated porous media
 
At the Department of Earth & Environmental Science at the University of Pennsylvania (UPenn), I am examining the transport and aggregation of non-spherical colloid particles (e.g., asbestos) through porous media. The broad goal of the National Institute of Environmental Health Sciences (NIEHS)–funded project is to improve the understanding of how asbestos fibers (chrysotile) form aggregate and transport in the porous geomaterials as well as in vivo, so that its implications on environmental exposure routes and subsequent development of lung cancer can be linked.

 

References
 

1. Seiphoori, A., Ferrari, A., and Laloui, L. (2011). An advanced calibration process for a thermo-hydro-mechanical triaxial system. International Symposium on Deformation Characteristics of Geomaterials, vol. 1, pp. 396-403, Seoul, South Korea.
2. Seiphoori, A., Ferrari, A., & Laloui, L. (2016). An advanced doubled-wall triaxial cell for thermo-hydro-mechanical analysis of unsaturated geomaterials. ASTM Geotechnical Testing Journal (under review).
3. Seiphoori, A., Ferrari, A., & Laloui, L. (2014). Water retention behaviour and microstructural evolutions of MX-80 bentonite during wetting and drying cycles. Géotechnique Vol. 64, No.7, 1-14.
4. Keller, L.M., Seiphoori, A., Gasser, P., Lucas, F., Holzer, L., & Ferrari, A. (2014). The pore structure of compacted and partly saturated MX-80 bentonite at different dry densities. Clays and Clay Minerals, Vol.63, No.3, 174-187.
5. Seiphoori, A. and Laloui, L. (2016). Water retention and hydro-mechanical modelling of highly swelling clays. Computers and Geotechnics (manuscript in prep.).
6. Ferrari, A., Seiphoori, A., Rüedi, J. & Laloui, L. (2014). Shot-clay MX-80 bentonite: an assessment of the hydro-mechanical behaviour. Engineering Geology 173, 10-18.
7. Seiphoori, A., L. Laloui, A. Ferrari, M. Hassan, & W. H. Khushefati (2015) Water retention and swelling behaviour of granular bentonites for application in Geosynthetic Clay Liner (GCL) systems. Soils and Foundations, Vol. 56, No.3
8. Seiphoori, A., Whittle A.J., Konrad J. Krakowiak, & Einstein, H.H. (2016). Insights into Diagenesis and Pore Structure of Opalinus Shale through Comparative Studies of Natural and Resedimented. Clays & Clay Minerals (under review).
9. Seiphoori, A., Moradian, Z., Einstein, H.H., Whittle, A.J. (2016). Microstructural characterization of Opalinus shales, 50th US Rock Mechanics/Geomechanics Symposium, pp., Houston, USA.

 

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