PRR Project

Summary

With the recent Recovery and Resilience Plan, there has been considerable growth in the construction of important infrastructures in Portugal, namely those related to the expansion of the Lisbon and Oporto subways  and the construction of urban drainage systems, as is the case with the Lisbon Drainage Plan designed to safeguard the city against flooding, a problem that is predicted to worsen due to the increasing use of land and the effects of climate change.Due to the unique nature of these projects, ground improvement techniques such as stone columns, vibrocompaction, vibroreplacement, compaction or permeation grouting, soil mixing, jet grouting, and slurry barriers are frequently used to overcome challenges related to ground conditions and surface occupation while keeping construction costs low.Although ground improvement was practiced soon after the beginning of geotechnics as a discipline, a comprehensive textbook was only published in 1990 (Hausmann, 1990). Indeed, the credit for the development of ground improvement techniques lies largely with innovative contractors, who, for proprietary reasons, did not immediately disseminate the newly acquired knowledge.As ground improvement is closely tied to construction, a thorough understanding of equipment and techniques is necessary for appropriate design. Nonetheless, recent advances in the field have relied increasingly on theoretical and experimental research studies. While many ground improvement techniques are tried and proven, there are continuous developments in design, equipment, construction techniques, and quality control measures for these established methods. On the other hand, its application has expanded to include ground at contaminated land and hazardous waste sites, suggesting considerable application potential in Portugal that has not yet been fully realised.The Geotechnics Department (DG) of LNEC has conducted research on ground improvement, resulting in the development of M.Sc. and Ph.D. programs, and research projects in the fields of jet grouting, deep soil mixing, self-hardening slurry walls, and soil-bentonite cut-off walls. In addition, DG provides technical and scientific support from the design phase to the subsequent execution of works for projects as mentioned above. As a result, LNEC is best positioned to bridge the gap between construction and design and to the development path of new methods and applications and share all the information needed for safe, cost-effective and sustainable projects.More recently, there has been a growing concern about the development of sustainable, constructive solutions – which is one of LNEC’s main research goals. Future projects must explicitly consider sustainability effects in decision-making, as well as safety, performance, and construction and maintenance costs, to find solutions that balance the 2030 Agenda´s goals of economic growth, social welfare, and the preservation of the environment.In this context, the development of new materials and material combinations, as well as the use of specific industrial wastes with cementitious properties, may contribute to more sustainable solutions by replacing cement, which production accounts for 5% of total carbon dioxide emissions. Furthermore, as the availability of high-quality bentonite decreases, future research should focus on the development of materials that can replace it, much like synthetic polymers.Keeping the aforementioned in mind, the following tasks are foreseen to be developed by the prospective employee:i. Update the state of the art in recent ground improvement technological developments, particularly concerning quality control, post-construction monitoring, and detection of anomalies. Update the state of the art regarding new approaches of ground improvement methods, such as those that use biological methods to increase strength, reduce permeability, or reduce liquefaction potential, or those used on contaminated land and hazardous waste sites to contain contaminants and reduce the risk to public health and the environment.ii. Incorporation of sustainability criteria into soil improvement methods by: a) studying methodologies for assessing the impact of the solution on its lifetime, considering different dimensions – economic and environmental; b) developing more environmentally friendly materials to replace carbon high-emission products like cement and natural but limited resources like bentonite.iii. Optimization of the applicability of ground improvement techniques based on ground characteristics and improvement goals.iv. Contribution to training young researchers in Ph.D. programs.v. Participation of LNEC in international research projects on the topic.vi. Dissemination of research results.The potential employee should hold a Ph.D. in Civil Engineering specializing in geotechnics. Her/his background and experience should highlight practice in research, teamwork, and the ability to analyse problems critically.