CEE 200 Sec 1 Seminar: Shahrzad Roshankhah


CEE 200 Sec 1 Seminar: Shahrzad Roshankhah

Speaker:
Affiliation:

cee200: Structural & Geotechnical Engineering Seminar

UCLA Civil & Environmental Engineering Department

Geo-Engineering for Sustainability of
Energy Infrastructures

Shahrzad Roshankhah, Ph.D.

Post-Doctoral Scholar, California Institute of Technology

Energy related geo-systems involve a wide range of engineering solutions from deep fossil fuel and geothermal energy reservoirs and energy piles to energy geo-storage facilities and waste repositories (CO2 and nuclear). The analysis and optimum design of these systems require proper understanding of geo-materials including their response to extreme temperature and high stress excitations, the implications of mixed-fluid conditions when contrasting fluid viscosities and densities are involved, the effect of static and cyclic coupled hydro-thermo-chemo-mechanical excitations and rate effects on the behavior of long lifetime facilities.

In the first part of this talk, we will review the fundamentals of heat conduction in continuum and discrete materials and propose approaches to quantify and tune the thermal conductivity of composite two-phase granular samples in order to attain enhanced performance in thermal geo-systems such as heat storage facilities. The macroscale thermal response of particulate materials is intimately related to contact- and pore-scale conduction and deformation processes at interparticle contacts. Therefore, fabric and stress level govern the thermo-mechanical behavior. Pore-filling liquids also play a critical role in heat conduction as liquids may provide efficient conduction paths between solid grains depending on their other physical properties. Conversely, grains and fluids can be selected to attain very low thermal conductivity in order to create mechanically sound thermal barriers. In this study, uncemented soils and other artificial granular materials have been tested, and the evolution of their bulk thermal conductivity has been quantified as one or more parameters such as fabric, mineralogy, stress level, and pore fluid change.

In the second part of this talk, we will consider natural rock masses with various geologic origins. Heat and mass recovery from rocks of low permeability is enhanced by injecting fluids at high rates to cause hydraulic fractures. In our study, shale rock specimens are loaded to in-situ stress conditions and fracked by high fluid pressures in the laboratory. The path, morphology, and velocity of the induced hydraulic fracture and its interactions with the rock’s natural fractures are recorded with state-of-the-art optic and electromagnetic imaging techniques. The goal is to quantify the hydro-mechanical behavior of rocks subjected to hydraulic stimulation through direct modeling. Other scaled experiments reveal the physical phenomena taking place during and after hydraulic fractures in pre-structured rocks and highlight the extensive self-propped dilational distortion that the medium could experience if designed properly. This result explains the higher production rate from shale gas and fractured geothermal reservoirs that is observed in the field, contrary to theoretical predictions. In both parts, the research approach combines numerical and experimental studies with analytical methods.

Where:   Haines Hall 220

When:    4 – 6 PM, Tuesday, May 29

Dr. Shahrzad Roshankhah is a postdoctoral scholar at the California Institute of Technology, Department of Mechanical and Civil Engineering. Inspired by unprecedented challenges facing our era on water, energy, and the environment nexus and ample opportunities to solve them, Roshankhah is passionate to develop more accurate models for the hydro-thermo-mechanical behavior of geomaterials at extreme conditions (e.g., high temperatures, stresses, and fluid pressures). At Caltech, she studies the propagation pattern and regime of hydraulic fracture in rocks as well as the elastoplastic behavior of particle impacts in granular flows important for the proper design of proppant injection and sand production in the recovery of geological energy resources. Roshankhah received her PhD in geotechnical engineering from the Georgia Institute of Technology in 2015. As a researcher in geoengineering, Roshankhah specializes in designing experimental setups that simulate in-situ conditions while minimize uncertainties, utilizing sensor technology that capture the governing physical phenomena in geomaterials with proper spatial and temporal resolutions, and data analysis. After earning her MSc degree in geotechnical engineering from Tehran Polytechnic in 2006, Roshankhah worked in engineering consulting companies for four years, designing buildings and geostructures as well as seismic rehabilitation of existing buildings. Later, she formed and led committees to create and revise several national technical standards, such as guidelines for seismic rehabilitation of existing buildings, assessment of liquefaction potential, and design of earth dams. Roshankhah is the recipient of several educational and leadership awards (from NSF, GaTech, Caltech, etc.) and certificates (e.g., seismic rehabilitation of buildings, operation of Scanning Electron Microscopy, and computational geomechanics) and has been invited to serve in committees as a technical reviewer for specialized symposia, scholarship distribution, and promoting the participation of minority groups in STEM fields.

Date/Time:
Date(s) - May 29, 2018
4:00 pm - 6:00 pm

Location:
Haines Hall 220
375 Portola Plaza Los Angeles CA 90095