The Italian Geotechnical Society (Associazione Geotecnica Italiana – AGI) organized the annual Croce Lecture on the 11^th of December at the “Centro Congressi Frentani” in Roma (Italy). The Conference is dedicated to the memory of the late Professor Arrigo Croce, who was the first professor of Soil Mechanics and Geotechnical Engineering in Italy, President of the AGI, and also Vice-President for Europe of the ISSMGE.

The Croce lecture 2019 was delivered by Prof. Heinz Brandl, from Vienna University of Technology with the title: “Structures in unstable slopes – retaining structures, bridges, earth reinforced structures”.

The conference was opened with the greetings from Nicola Moraci, President of the Italian Geotechnical Society, and the Croce lecturer was introduced by Daniele Cazzuffi, President of the AGI-IGS who highlighted the important contributions of Prof. Brandl in the area of stabilization and grouting of unstable slopes, and in particular of the geotechnical engineering with geosynthetics.

Professor Brandl has been full University Professor for Geotechnical Engineering since 1977 chairing the Geotechnical Institute founded by Professor Terzaghi in 1928 at the Vienna University of Technology. He is a member of the Royal Academy of Sciences of Belgium, of the International Academy of Engineering (Moscow) and other Scientific Academies. Since 2009, he becomes an active Professor Emeritus. Since June 2003 he has been the President of the Austrian Society for Engineers and Architects (founded in 1848). He received numerous national and international awards, honorary doctorates and other honours : among the various recognitions, Heinz Brandl gave the 2010 Giroud Lecture in Guaruja (Brazil).

The outstanding Croce lecture provided an excellent state of art on lessons learned from the past and provided future perspectives in landslide prevention and stabilization as well as risk assessment. Roads, highways and railways are frequently running along unstable slopes which often are seismic zones as well. The lecture shown the influence of water and soil shear strength parameters on slope stability, especially the importance of determining the residual shear strength in addition to peak values. Moreover, Prof. Brandl highlighted that very often the creeping phenomena causes excessive lateral pressures on structures exceeding by far the earth pressure at rest, as theoretical investigations and numerous in situ measurements since the 1970s have clearly shown.

Building in unstable slopes requires engineering flexibility and structures which can be strengthened step by step if necessary. This involves semi-empirical design, based on calculated risk and the observation method, including contingency plans and long-term monitoring. Several case histories demonstrate this engineering philosophy which has been proved to be suitable already for 40 years; during the Croce lecture, experiences of long-term monitoring were also given.

More than 200 geotechnical professionals from different sectors including universities, public institutions, designers, enterprises and contractors came from different parts of the world to gather together for this special event.

Nicola Moraci closed the session with the announcement of the next Croce Lecturer for the following year 2020, which will be Prof. Paolo Simonini from Padua University : he will speak about the geotechnical aspects of the defense of the Venice lagoon.

The 2019 annual conference closed with a light buffet where all the participants spent a nice time together and have the chance to exchange traditional greetings ; then the 2019 Croce lecture was followed with an informal dinner with Prof. Brandl and with the leadership of AGI and AGI-IGS.

The Croce lectures from the past lecturers can be downloaded from the website of AGI (http://www.associazionegeotecnica.it/rig/croce_lecture).

Reported by Daniele Cazzuffi AGI-IGS President and Giuseppe Cardile Secretary of the AGI-IGS