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Institute of Advanced Study

Professor Ronaldo Borja

IAS Fellow at St Cuthbert's Society, Durham University (January - March 2008)

Professor Ronaldo I. Borja has degrees in civil engineering and mechanical engineering, with a PhD in civil engineering from Stanford University. He has held visiting professorships at the Polytechnic University of Madrid in 1994, and at the Polytechnic University of Catalunya in Barcelona in 2001. He also has given short courses at the University of Rome "La Sapienza" and at the University of Naples, Federico II. Prior to joining the faculty in the Department of Civil and Environmental Engineering at Stanford University, he has held an assistant professorship at the University of the Philippines.

Professor Borja works in theoretical and computational solid mechanics with application to geomechanics and geosciences. His research includes developing theoretical and computational models for capturing large deformation and instability phenomena in soils and rocks, including the initiation of deformation bands, liquefaction of saturated sands, earthquake fault nucleation and propagation in rocks, pore collapse in high porosity solids, and folding and fracturing of geologic media. He has also developed theoretical and numerical models for capturing fluid flow phenomena in fully and partially saturated granular materials, and has used them to study the initiation of landslides and debris flow in saturated slopes. Professor Borja is currently involved in a project sponsored by the US National Science Foundation dealing with kilometer-scale folding of rock strata superimposed with kilometer-scale faulting and centimeter-scale fracturing of these materials.

Professor Borja has participated in a number of projects in which he developed numerical models for critical structures and historical monuments. He has been involved in the restoration of the Tower of Pisa, where he developed a three-dimensional nonlinear finite element model to predict the movement of this tower due to changes in the groundwater table. He has developed a three-dimensional finite element model of the South Memnon Colossus, an ancient landmark in Luxor, Egypt, to investigate its dynamic response to earthquake excitation. He has constructed a nonlinear finite element model to study the effect of dynamic soil-structure interaction on a nuclear power plant structure subjected to a strong seismic ground motion.

Professor Borja is currently on the editorial boards of a number of international journals, including Computer Methods in Applied Mechanics and Engineering, Computers and Geotechnics, International Journal for Numerical and Analytical Methods in Geomechanics, and International Journal of Geomechanics. He also serves as editor of Acta Geotechnica, a newly launched journal dealing with contemporary issues in geoengineering and geosciences.

During his time at the IAS, Professor Borja will be finishing his two books, the first dealing with modeling and computation in plasticity, and the second dealing with solid deformation-fluid flow problems. He also will interact with a number of faculty in engineering and geosciences at Durham University to work on various problems dealing with multiscale phenomena. Multiscale problems of engineering interest to him range from the nano-scale to the meter-scale, whereas problems of interest in geosciences can be as large as the kilometer-scale.

Fellow's Home Page

IAS Fellow's Public Lecture - Deformation and failure processes in geologic materials at scales from grains to basins

Sediments and sedimentary rocks display a wide range of deformation and failure processes and structural styles that reflect their porous and granular nature, variable loading conditions and loading rates in active depositional settings, and complex chemical/mechanical water-sediment-rock interactions. A basic understanding of these multiscale deformation and failure processes is a prerequisite for successful energy and water resource management and natural hazard mitigation.

IAS Insights Paper


Rainfall infiltration weakens unsaturated earthen slopes, causing the soil mass to move rapidly downhill. Increased saturation and fluid flow are two important triggers of slope movement, and to date no physics-based modeling approach can represent the combined effects of these two factors in a systematic and quantitative way. In this article I briefly review a commonly used analytical approach based on the limit equilibrium methods for quantitative analysis of slope stability, and highlight their inability to handle the effect of rainfall infiltration on the triggering of slope failure. I describe an alternative analysis approach based on continuum modeling and show some examples where I have used this approach for studying the effect of rainfall infiltration on the stability and movement of unsaturated earthen slopes.

Insights Paper