Tunnelling beneath piled structures in urban areas

The provision of effective infrastructure systems (transport, power, water, waste) is something most people take for granted, yet its importance is paramount when considering public safety and economic growth. Furthermore, the increase in urban growth, which could reach 70% in 2050, is leading to increased demand for underground infrastructure systems (railways, metros, etc.). Underground infrastructure systems provide sustainable solutions in large cities that help to optimise the use of surface spaces and minimise pollution; however, they also require the construction of new tunnels (tunnelling), deep-excavations and shafts that cause ground movements, which raise concerns related to serviceability and safety of existing buildings, pipelines, tunnels, and other infrastructure in congested urban areas.

The project main aim was to developed simplified numerical solutions, implemented in MATLAB scripts, that will benefit engineers that need to assess the risk of tunnelling in urban areas during their design of underground construction. In particular, soil-structure interaction models were developed that allow estimating the response of pile groups and piled structures to external actions and tunnelling-induced ground movements, with a focus on predicting foundation and structure distress/damage. Also, design-charts are proposed to facilitate the quick exploitation of research outcomes in practice. Although the original research proposal aimed to focus on tunnelling beneath piles and piled structures, the project was expanded towards the investigation of the following thematic areas, always related to urban tunnelling: i) the response of buildings on shallow foundations to tunnelling in urban areas; ii) deep-excavations next to pile foundations; iii) distortions and movements of existing tunnels and utility pipelines due to underneath tunnelling.

For the first time, interaction models were proposed during this project that allow for a coupled analysis of soil-pile-structure interaction induced by either tunnelling or deep-excavations while considering nonlinear soil-pile transfer mechanisms, stress relief, and layered ground conditions. This overcomes the limitations of traditionally available models focusing on a portion of the full geo-structural domain, which necessarily rely on simpler (and possibly simplistic) boundary conditions at either the geotechnical or structural sub-domain. Results, at the highest standards for civil engineering, were published in peer-reviewed prestigious journals (Q1 for geotechnical engineering) and international conference proceedings. In particular, the project has led to 5 papers published in peer-reviewed prestigious Journals, 4 journal papers under review, 4 papers published in the proceedings of international conferences as well as 6 conference papers to be published in 2021 (conference postponed due to the pandemic). To disseminate results, the Experienced Researcher attended four international conferences. Also, he co-organised the Mini-Symposium "Building and infrastructure response to ground movement" at the 16th International Conference of the International Association for Computer Methods and Advances in Geomechanics (IACMAG2020) to be held in Turin (Italy) that is being followed by the preparation of a Special Issue by the "Tunnelling and Underground Space Technology" Journal, extended to all the tunnelling community. Finally, seminars and talks were given at Research Centres and industrial design firms across the EU.

The simplified models developed during TUBEURB for the efficient evaluation of excavation-induced soil-foundation-structure interaction will facilitate the shift towards optimised performance-based design in practice, in the day-to-day design and risk assessment of engineers, by allowing for the quick understanding of how geo-structural systems (buildings, piled structures, existing tunnels) behave during excavations and underground construction. These design-oriented tools are needed to satisfy the urban demand for green infrastructure. In particular, developed simplified models will help engineers to overcome overengineering and reduce the environmental impact of underground infrastructure construction (less carbon footprint, and fewer construction materials and disposal) complying with the EU sustainability aims.

Regarding the development of a network of academic and industry collaborations, new contacts spanning across EU were established (by the attendance of conferences, giving seminars at leading institutes and design firms, during the placement). In particular, the collaborations established by this intersectoral project led to a strong research synergy between the involved Universities in Madrid, Barcelona, Nottingham, Cambridge and Bologna. This has become a platform for international cooperation and joint applications to secure funding. This has already had an impact; in fact, the research project TUTSS granted to the U. Politécnica Madrid includes researchers at the U. Politècnica Catalunya and U. Nottingham.

Periodic Reporting for period 1 - TUBEURB (Tunnelling beneath piled structures in urban areas)

Compartir esta página

Descargar