The project stems from the need of updating the current engineering practice in underground constructions in urban areas, which is based on simplified design assumptions that necessarily lead to rather conservative construction solutions, often complemented by damage prevention systems in the structure and/or containment measures in the soil. This leads to a general increase in project time and costs and often inhibits the use of historic structures by inhabitants for a long time.
The proposed research has the following objectives: i) identify a new metrics to classify the level of damage induced in masonry structures subjected to typical tunnelling-related displacement patterns; ii) select the procedures to run coupled numerical models accounting for the underground excavation processes, their effects on the involved soil deposits and the resulting interaction with masonry surface structures; iii) validate the outcomes of the above objectives by carrying out the challenging numerical back-analyses of the tunnelling-induced effects in a real historical structure, the Aurelian walls at Porta Metronia, recently under passed by the twin tunnels of the metro C line in Rome.
The scientific outcomes of the proposed project are expected to impact the civil engineering academic community, with particular reference to the geotechnical and tunnelling engineering ones. The proposed framework might also impact the industry involved in the design and construction of tunnels in urban area, providing more reliable and cost-effective design tools to be adopted in fragile environments involving historical community assets. Finally, at the social and community level, the outcomes of this research will rise interest from public and private facility managers and owners of historical buildings, committed to guarantee high standards of protection of their assets.
According to United Nations projections, 2.5 billion more people will live in urban areas by 2050, which leads to a total amount of almost two thirds of global population. However, as the world continues to urbanise, many countries will face challenges in fulfilling the needs of their growing urban inhabitants related to housing, transportation, or energy systems. This future perspective also calls for an adaptation of infrastructures, mostly underground, for mobility as well as for energy, waste or data transport purposes.
It is a fact that, especially but not limited to the European context, big cities are often characterised by the presence of invaluable heritage buildings, that should be preserved while new infrastructures are being constructed. Rome represents a paradigmatic case study of such difficult coexistence: in fact, in this municipality billions of euros have been invested in the Metro C line project, planned to develop for at least another 4 km with the construction of 5 new stations (data from www.metrocspa.it).
In the perspective of a sustainable infrastructural expansion, the protection of existing structures, especially if endowed with historical and artistic value, has a pivotal importance and affects both the time required to complete the underground infrastructure and its overall cost.
This research project aims to propose and validate new tools to be adopted at the design stage of next-generation underground infrastructures. Hence, the proposed research activities are expected to potentially impact not only the related scientific communities, namely those involved in geotechnical and tunnelling engineering which will be updated by the related scientific publications, but also several professional subjects involved in design and construction of underground infrastructures in historical urban areas.
As discussed in the previous sections, the purpose of the project is to produce a breakthrough knowledge in the assessment of the impact of tunnelling in urban areas on heritage buildings. This is expected to have an immediate fallout on a wide number of relevant stakeholders, as mentioned in the following.
From a pure technological point of view, the background knowledge of this research project is sound and well established. The scientific progress in the field occurred in the past decades has improved the quality and safety of the underground activities worldwide and this allows the identification and the optimisation of work phases, technological solutions and implementation methodologies, achieving both time and cost savings. Within this research project, the analysis and simulation tools for the prediction of the interactions between the tunnelling activities, the involved soil deposits and the surface structures will be improved and validated against ideal and real case studies. Hence, the foreground knowledge of the research project will provide an important evolution in the relevant industry and professionals, allowing to safer and more reliable design and construction in fragile environment involving community assets. More broadly, this will contribute to the digital transformation of the design, construction and management of underground infrastructures in the built environment.
From an economic perspective, it is worth noting that an important portion of the budget allocated for underground construction in the built environment is related to induced damage and its mitigation. Therefore, improving the analysis of the soil-structure interaction, thus achieving a reliable prediction of the induced damage, is surely a unique opportunity to reduce the construction cost of an infrastructure. Potential beneficiaries are the public sector as well as the civil engineering companies involved in design and construction of urban underground works.
At the social and community level, the outcomes of this research will rise interest from both private and public sector among facility managers and owners of monumental and historical buildings. Indeed, their institutional activities of verification, authorization and control of urban excavation and tunnelling projects require a suitable data management framework, tailored for accurate prediction of the effects on the historical built assets. Our project will help providing a sound technical support to the decision makers, which will be more reliable than the current practice often lacking rigorous validation.