NTU-CEE Distinguished Seminar Series: Professor Ronaldo Borja

Organized By

CEE Seminar Committee

Host By

Professor Chu Jian

Topic

Phase Field for Compaction Band: Capture of Grain Crushing and Permeability Evolution in Heterogenous Media

About the Seminar

Compaction bands form when the pore spaces between the solid grains of a rock mass collapse into a narrow zone. This deformation style has attracted much attention in the theoretical and numerical modeling community since the porosity reduction associated with pore collapse reduces the overall permeability of the rock, thus enhancing its potential to serve as a fluid flow barrier. In this talk, I will use the phase-field approach to show how grain crushing and fluid flow impact the formation and propagation of compaction bands.

I will employ a three-field finite element formulation in terms of solid displacement, fluid pressure, and the phase-field variable for this purpose. Using material parameters calibrated from real rocks, I will show how the volume constraint imposed by fluid flow impacts the stress-strain responses of the rock and the ensuing geometric style of the compaction band.

About the Speaker

Ronaldo Borja was born and raised in the Philippines. He obtained his Bachelor’s degree in Civil Engineering from the University of the Philippines. He then attended Stanford University under a UNESCO Fellowship, where he obtained his Master of Science degree in Mechanical Engineering (Applied Mechanics) and Ph.D. in Civil Engineering. He returned briefly to the Philippines after the completion of his Ph.D., and then joined Stanford University’s Civil Engineering Department as a faculty one year later.

His main areas of research include theoretical and computational solid mechanics, geomechanics, and geosciences. Ronaldo Borja is the author of a textbook entitled Plasticity Modeling and Computation published by Springer. He currently serves as editor of two high-impact journals in his field, the International Journal for Numerical and Analytical Methods in Geomechanics published by Wiley, and Acta Geotechnica published by Springer. He is the recipient of the 2016 Maurice A. Biot Medal of ASCE and the inaugural recipient of the 2025 Mary F. Wheeler Medal of USACM."

Registration

Click here for registration
(Registration closes on 15 July 2025, 09:00am)