Keynote Lectures

Prof. Dr. Eng. Atilla Ansal

Vice-President of European Association for Earthquake Engineering (EAEE)

He received his Ph.D. in Geotechnical Engineering from Northwestern University, USA in 1977. He was promoted to full Professorship in 1988 in Istanbul Technical University. He moved to Kandilli Observatory and Earthquake Research Institute of Bogaziçi University in 2002. Since March 2012, he is professor in the Engineering School of Ozyegin University and Chairman of Civil Engineering Department.

He has been the Secretary General of the European Association for Earthquake Engineering during 1994-2014; President during 2014-2018 and Vice-President for 2018-2022. He is the Editor in Chief of the Bulletin of Earthquake Engineering published,12 issues yearly and the book series on “Geotechnical, Geological and Earthquake Engineering” by Springer since 2002.

His main areas of interest are seismic microzonation methodologies, earthquake scenarios, effects of geotechnical factors on earthquake damage, cyclic behaviour of clays and sands, liquefaction,variability of strong ground motion characteristics. He published about 250 articles in conferenceproceedings, journals, books and as technical reports in English and Turkish. He was the recipient ofthe Third Ord.Prof.Dr. Hamdi Peynircioglu Lecture Award in 1988, given by the Turkish NationalCommittee on Soil Mechanics and Foundation Engineering, the Third Prof.Dr.Rıfat Yarar Lectureaward in 2015, given by Chamber of Turkish Civil Engineers and Earthquake Engineering Committeeof Turkish Earthquake Foundation and he was the 15 th Prof. Nonveiller Lecturer elected by theCroatian Geotechnical Society.

Lecture Title: Seismic Microzonation for Damage Mitigation

Prof. Dr. Eng. Giovanni Barla

Former Professor of Rock Mechanics at Politecnico di Torino; Editor of the Rock Mechanics and Rock Engineering Journal

Giovanni Barla, former professor of rock mechanics at Politecnico di Torino, has been head of the Department of Structural and Geotechnical Engineering and vice-president of the School of Engineering. He has been instructor and associate professor at Columbia University, New York.Giovanni graduated in mining engineering at Politecnico di Torino, obtained the MScEng Degree and the DrEngSc Degree at Columbia University, School of Engineering and Applied Sciences, New York, defending a thesis on the analytical and numerical analysis of stress distribution around underground excavations.Giovanni Barla has been president of the Italian Geotechnical Association (AGI) and vice-president for Europe of the International Society for Rock Mechanics and Rock Engineering, ISRM. Giovanni is editor of the Rock Mechanics and Rock Engineering Journal. He received the ISRM fellow nomination, the IACMAG award for outstanding contributions, and the emeritus membership of AGI. He is honorary professor of Chongqing and Tianjin University and a member elected of the Torino Academy of Science.

The research interests of Giovanni Barla span over a variety of topics in the fields of rock mechanics, tunnel engineering, rock slopes and dam engineering, numerical methods in geomechanics. He is among the small group of European researchers who studied and applied the finite element method in the field of rock and soil mechanics since the early developments of the technique. He is author and co-author of more than 300 papers, which cover subjects such as laboratory and in situ testing, rock mass characterization and classification; numerical modelling; performance monitoring and back analysis; rock slopes; tunnels and caverns.Giovanni Barla is also an active international consultant. His activity is strictly related to his studies, providing valuable hints for pursuing new research topics, and brought him to become, during the nineties, principal and member of the International Board of Golder Associates. The projects in which he acted as designer, geotechnical consultant or responsible of the numerical studies are numerous and concern a variety of topics in rock engineering, including rock slopes, deep seated rock slides, dam foundations, conventional and mechanized tunnel excavations, and mining engineering.Giovanni is presently involved in a number of underground projects in Italy and Abroad. He is contributing at the design stage and during construction of the Alpine Base Tunnels and tunnels being excavated in difficult ground conditions, by using both conventional and/or mechanized excavation methods. In these cases rock mechanics an rock engineering concepts are being applied systematically and novel methods for efficient and safe construction underground are being developed. Also, the most interest is devoted to the development of civil protection strategies for rockslide hazard assessment, methods for real time monitoring and early warning, with reference to natural slopes where infrastructures and inhabited areas are located.

Lecture Title: Dealing with Rock Falls in Inhabited Areas

Among the “Grand Challenges for Engineering”, identified by the Expert Committee of the NAE (National Academy of Engineering), one may point out the Impact of rock slopes instabilities on people, man-made infrastructures, and inhabited areas. In relation to this, very important are rock falls that may pose a significant threat on inhabited areas located immediately down-slope. It is to be highlighted that rock falls are a major cause of landslides fatalities.The purpose of the present lecture is to illustrate first typical rock fall problems with examples taken from practice and personal experience. Advanced and novel investigative methods to study and characterize the rock mass in detail and define the likely modes of rock instability initiation and failure will be considered. Then, the attention will be dedicated to the three-dimensional modelling of the rock fall process down-slope.Two case studies of high, steep, and jointed limestone rock cliffs in Italy, characterized by the presence of rock volumes of different shape and size, in limit equilibrium conditions, are described in detail. It is highlighted that in both cases the rock volumes when detached from the cliffs, following a series of leaps and bounds down slope, may reach and damage town houses located at the slope toe.The studies for analyzing the rock cliff stability conditions are presented together with the kinematic simulations of the rock falls down slope considered, also with the intent to find the type and location of the passive measures to be implemented. Depending on the source of instability, being it localized or distributed along the cliff, studies of the structurally controlled mechanisms (e.g. plane and wedge sliding and/or toppling) were undertaken by using Conventional Mapping and Terrestrial Laser Scanning methods.

Prof. Dr. Eng. J.Carlos Santamarina

Distinguished Professor, Energy GeoEngineering Laboratory (EGEL), ANPERC, KAUST

J. Carlos Santamarina (Professor - KAUST) graduated from Universidad Nacional de Córdoba and completed graduate studies at the U. Maryland and Purdue U. He taught at NYU-Polytechnic, U. Waterloo and at Georgia Tech before joining KAUST.His team explores hydro-chemo-thermo-mechanical coupled processes and advances innovative characterization techniques for soils and fractured rocks, with applications in energy geo-engineering and deep-sea mining. The team’s research results are summarized in two books and more than 300 publications. Former team members are faculty members at more than thirty universities, researchers at national laboratories, or practicing engineers at leading organizations worldwide.Dr. Santamarina is a frequent keynote speaker at international events, a member of both Argentinean National Academies, and has participated in several Committees of the USA National Academies. He is the recipient of two ASTM Hogentogler Awards, was the 2012 British Geotechnical Association Touring Lecturer, and delivered the 50th Terzaghi Lecture in 2014.

Lecture Title: Long-term response of soils subjected to repetitive loads – Engineering Implications.

Geotechnical structures often experience repetitive loading cycles of all kinds, including: mechanical (wind, waves, pavement, railroad, and foundations), pore water pressure (tidal, pumped hydro), suction (dry-wet cycles), pore fluid chemistry, and thermal cycles (LNG foundations, thermally active piles, exposed rock faces, freeze-thaw).Repetitive loads can cause significant accumulations of volumetric strain (terminal void ratio) and plastic shear deformation (shakedown or ratcheting), lead to accelerated heat and chemical transport (AC-diffusion), and alter soil properties (from small strain stiffness and compression index to friction angle and hydraulic conductivity). Controlled particle-scale and pore-scale experiments and simulations provide unique insight into underlying mechanisms that explain the observed macro-scale response.The design of geo-structures needs to consider the influence of repetitive loads on long-term performance, serviceability, and safety. Convenient close-form, first-order engineering estimates are based on asymptotic conditions (e.g., cumulative deformations in soils and rocks, and transport processes). However, complex boundary conditions require numerical simulations. Time-stepping using classical constitutive models is practical for a small number of cycles, but it requires major computational resources when the number of load repetitions is high; furthermore, the accumulation of numerical errors may distort the predicted response. Indeed, engineering projects that involve a very large number of cycles may require a hybrid approach: empirical strain accumulation functions to estimate strain accumulation during repetitive loading complemented with a classical algorithm to satisfy equilibrium and compatibility at selected stages during repetitive loading.

Prof. Dr. Eng. Chandrakant S. Desai

Founding President, General Secretary and Treasurer of the International Association for Computer Methods and Advances in Geomechanics (IACMAG)

Chandrakant S. Desai is a Regents' Professor (Emeritus) , Department of Civil Engineering and Engineering Mechanics, University of Arizona, Tucson, Arizona. Dr. Desai has made original and significant contributions in basic and applied research in material-constitutive modeling, laboratory testing, and computational methods for a wide range of problems in civil engineering related to geomechanics/geotechnical engineering, structural mechanics/structural engineering, mechanical engineering and electronic packaging. Dr. Desai’s research on the development of the new and innovative disturbed state concept (DSC) for constitutive modeling of geomaterials and interfaces/joints has found significant engineering applications. In conjunction with nonlinear finite element methods, it provides a new and alternative procedure for analysis, design and reliability for challenging and complex problems of modern technology. He has authored/edited about 20 books, 19 book chapters, and has been author/coauthor of over 320 technical papers in refereed journals and conferences.

Dr. Desai’s research contributions have received outstanding recognitions at national and international levels, some of which are indentified as: (a) development and applications of finite element method for problems involving interaction between structures and foundations, (b) the thin-layer interface element for simulation of contacts (interfaces and joints), (c) the Residual Flow Procedure for free surface seepage (d) a novel fundamental approach for microstructural instability including liquefaction, and (e) the disturbed state concept for modeling of engineering materials and interfaces, including thermo-mechanical and rate dependent behavior of materials in electronic chip-substrate systems.

His book on the finite element method (Desai and Abel) published in 1972 was the first formal text on the subject in the USA, second in the world. In 1979 he authored the pioneering and the first text for teaching the finite element method to undergraduate students. His book on Constitutive Laws for Engineering Materials (Desai and Siriwardane) in 1984 is considered to be the first on the subject that presented a combination of various material models based on continuum mechanics. In 2001, he authored the book on the Disturbed State Concept (DSC) that presents an innovative concept for modeling materials and contacts in a unified manner, combing the continuum mechanics models and a novel idea for introducing the discontinuities in the deforming material. In 1977 he co- edited (Desai and Christian) including his own contributed chapters, the first book on Numerical Methods in Geotechnical Engineering that deals with problems from geotechnical and structural engineering. In 20013-14 he has coauthored (Desai and Zaman) the book, Advanced Geotechnical Engineering: Soil-structure Interaction using Computer and Material Models, which is unique because of its scope, contents and connection between research and applications.

He was the founding General Editor of the International Journal for Numerical and Analytical Methods in Geomechanics from 1977-2000. He is the founding Editor-in-Chief of the International Journal of Geomechanics, published by Geo Institute, ASC, 2001-2008, and now he serves as its Advisory Editor. He has served as a member of Editorial Boards of 15 journals, and has been chair/member of a number of committees of various national and international societies. He is Founding President of the International Association for Computer Methods and Advances in Geomechanics (IACMAG). He is credited with introducing the interdisciplinary definition of Geomechanics that involves various areas such as geotechnical engineering and rock mechanics, static and dynamics of interacting structures and foundations, fluid flow through porous media, geoenvironmental engineering, natural hazards and earthquakes, landslides and subsidence, petroleum engineering, offshore and marine technology, geological engineering and modeling, geothermal energy, ice mechanics, and lunar and planetary geomechanics.

Dr. Desai has received a number of awards and recognitions, e.g., Fellow, National Academy of Engineering, India; Lifetime Achievement Award, Alumni Association of VJTI, University of Bombay; The Distinguished Member Award by the American Society of Civil Engineers (ASCE); The Nathan M. Newmark Medal, by Structural Engineering and Engineering Mechanics Institute, ASCE; The Karl Terzaghi Award, by Geo Institute, (ASCE); Honorary Professor, University of Nottingham, U.K.; Diamond Jubilee Honor, Indian Geotechnical Society; Suklje Award/ Lecture, Slovenian Geotechnical Society; HIND Rattan (Jewel of India) Award, by Non-resident Society, New Delhi, India; Meritorious Civilian Service Award by the U.S. Corps of Engineers; Alexander von Humboldt Stiftung Prize by the German Government; Outstanding Contributions Medal by the International Association for Computer Methods and Advances in Geomechanics; Outstanding Contributions Medal in Mechanics by the Czech Academy of Sciences; Clock Award for outstanding Contributions for Thermomechanical Analysis in Electronic Packaging by the Electrical and Electronic Packaging Division, ASME ; Five Star Faculty Teaching Finalist Award and the El Paso Natural Gas Foundation Faculty Achievement Award, at the University of Arizona, Tucson, Arizona.

Constitutive Modeling of geologic materials and interfaces Significant for Geomechanics

Behavior of geologic materials, interfaces and joints play the vital role for realistic and economical solutions for geotechnical problems under mechanical and environmental (fluid, thermal, chemical, electromagnetic, etc.) loadings. Characterization of the behavior, refereed as constitutive modeling, requires appropriate basic mechanics and physics, testing (laboratory and field), determination of parameters, validations at the specimen level and at boundary value problem level.

A brief review of available constitutive models will be followed by a description of the unified Disturbed State Concept (DSC). Material behavior involves simultaneous occurrence of factors such as elastic, plastic and creep deformations, volume change, stress path effects, microstructural modifications leading to cracks, fracture, failure, liquefaction, softening or degradation and healing or strengthening. Most available models allow for specific number of these factors, while unified models are desired that allow for, as necessary, simultaneous occurrence of the foregoing factors. The DSC with the hierarchical single surface (HISS) plasticity provides for such unique and versatile unified model.

A number of examples problems involving testing and modeling of a wide range of materials and interfaces like sand, clay, rocks, asphalt, concrete, alloys, silicon involving mechanical, thermal, fluid and chemical effects will be presented. Solutions and validations for practical problems involving laboratory and field measurements using computer (finite element) procedure with the DSC/HISS will be presented. They would include challenging problems in geotechnical, ground improvement, transportation (pavement), earthquake and liquefaction, underground works, seepage and consolidation, composites (electronic packaging), and motion of glaciers and ice sheets.The importance of appropriate constitutive modeling for realistic solutions in Geomechanics and general engineering cannot be overemphasized.

Prof. Dr. Eng. Pierre DELAGE

Professor, Ecole des Ponts ParisTech, Navier-CERMES; Chair of the Technical Oversight Committee of ISSMGE, in charge of supervising the activities of the 32 Technical Committees of the ISSMGE

Pierre Delage, Professor of Geotechnical Engineering at Ecole des Ponts ParisTech where he graduated as Civil Engineer prior to complete his PhD at Mines ParisTech and Université Paris VI. After a two year stay at the University of Sherbrooke (Canada), he contributed, back to France, to the development of CERMES (the geotechnical group of Ecole des Ponts, now included in Laboratoire Navier), that he directed from 2003 to 2010. He developed researches on the fundamentals mechanisms governing the macroscopic response of multi-phase soils and rocks submitted to changes in stress, water content and temperature effects (Thermo-Hydro-Mechanical couplings), with some pioneering contributions on the role of the changes in the pore size distribution in the volume change behaviour of soils, the stress-strain and failure behaviour of unsaturated soils or the thermal response of claystones. His researches concerned various applications related to sensitive clays, deep marine sediments, unsaturated soils, compacted soils, loess, oil reservoir chalks, oil sands, claystones and shales and, more recently, Martian regoliths, in the framework of the forthcoming NASA mission InSight on Mars.

He is a corresponding member of the French Academy of Agriculture, has been Chief editor of the “Revue Française de Géotechnique” and “Géotechnique Letters”. He has been or still is member of various editorial panels (Géotechnique, Computers and Geotechnics, Geotechnical Testing Journal, Geomechanics and Geoengineering, Rivista Geotecnica Italiana). He organised, with E. Alonso, the 1st Int. Conf. on Unsaturated Soils in Paris (1995), played an active role in the 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering (Paris 2013) and chaired the 3rd European Conf. on Unsaturated Soils (Paris 2016). He serves since 2013 as Chair of the Technical Oversight Committee of the International Society of Soil Mechanics and Geotechnical Engineering, in charge of supervising the activities of the 32 Technical Committees of the ISSMGE, under both Roger Frank and Charles Ng’s Presidential terms.

Lecture Title: On the Thermal Behaviour of Clays and Claystones

Particular attention has been paid for some time to thermal issues in soils and rocks, with respect to the storage of high activity exothermic radioactive waste at great depth. This field also concerns various Geo-energy issues, like the behaviour of thermal piles, heat storage in the ground, the burial of high voltage cables, non-conventional oil production and ground-atmosphere interactions. Whereas advanced in-situ experiments have been carried out in some underground research laboratories excavated in clays and claystones in Belgium, France and Switzerland, rather few laboratory data about the thermo-hydro-mechanical behaviour of claystones are available in the literature. Thermal testing of clay rocks actually requires adopting some soil mechanics concepts, concerning in particular saturation procedures and drainage conditions. Based on the use of specifically developed novel experimental devices, new data concerning the thermo-poro-elastic characteristics, the thermal volume changes (with special interest devoted to plastic thermal contraction), and thermal pressurisation issues in various clays and claystones from Belgium (Boom clay), France (Callovo-Oxfordian claystone) and Switzerland (Opalinus Clay) are presented. These new data are of significant importance in the assessment of the stability and long-term performance of radioactive waste disposal systems in clays and claystones.