DISCRET aims at demonstrating the possibility to detect and locate, in real-time, unusual or critical situations in urban areas, based on the analysis of cell phone network data. This detection will be complemented with information extracted from social networks (i.e., Twitter in the context of the project). A prototype of a warning platform for security and emergency operators will be implemented. Several recent research works have shown that major events induce locally significant modifications of the amount and nature of cellular network communications. These anomalies, typically concomitant with the unusual event, may be detected and located based on the network of cell phone antennas. Moreover, the early detection and localization of the events, together with the knowledge of the associated communication activity, allow for a more effective retrieval of information from the social networks. That permits to provide elements of description and context for the detected event and, therefore, to increase the value of the information conveyed by the population via channels that are not explicitly conceived for alerting purposes. DISCRET is a contribution to the second research axis listed in the call for proposals: “broadcasting private warnings”. The originality of the project lies in the joint usage of information generated by the population in a passive way (i.e., through the cell-phone communication activity) and the one produced in an active way through non-specific channels (i.e., online social networks). Social networks are not specifically dedicated to the broadcast of warnings, but they represent popular and major event information and broadcasting media.

This project goes beyond the current seismic risk assessment practice, incorporating recent progresses made in earthquake data observation and numerical modelling. The key scientific questions are (1) how the spatial variability of the near-field seismic ground motion impacts the soil and the structure; (2) how the seismic excitations damage and change the medium properties; and (3) how the building clusters contribute to the spatial variability of the ground motion in urban environment. We study the 2016 Kumamoto in Japan and the 2019 Ridgecrest in California earthquakes. These events have a large number of records in the vicinity of the epicentral area. We then target the impact of a building environment on the seismic risk assessment of the city of Quito, Ecuador, located on a piggyback basin created on the hanging wall of an active reverse fault. Our project respond to the needs of low-probability-high-consequences (LPHC) seismic risk in urban areas subjected to nearby earthquakes.

The detection and localization of utility networks in an urban setting has over the past few years become a topic of major interest. Standards (i.e. NF S 70-003) require a recognition of utility lines and an accurate location to within 11 cm conducted by certified service companies. According to feedback and evaluations from the scientific and technical teams within the Ministry of Ecological and Solidarity Transition, no solution currently meets the need for mapping underground networks over a large area at an acceptable cost for communities. For such an undertaking, a precise mapping of buried networks through combining physical methods, artificial intelligence (AI) methods and innovative technologies adapted to hybridization, offers an undeniable advantage for optimizing work in terms of both time and costs. This step will also lead to quality gains and help reduce the risks associated with sensitive networks. The PROMETHEUS project seeks to derive such a non-invasive methodological and technological solution, based on 3D radar technology, to structure the urban mapping of underground utility networks. This project is organized in five Work Packages (WPs), including project management (WP0) to coordinate the other WPs. WP1 focuses on the state-of-the-art and specifications for listing and selecting the influential indicators describing utilities and their environment. This selection step will generate output values or classifications for the machine learning techniques developed in subsequent WPs. WP2 is devoted to developing a hybridization approach (Deep Learning & Matrix Pencil Method) for automatic utility detection and classification applied to raw C-scan data acquired from a multi-antenna GPR device. EM signal processing can be introduced for target identification given its sole dependence on geometry and physical properties. This proposed identification step thus entails applying the high-resolution method (Matrix Pencil Method) to frequency responses. Next, a deep learning segmentation will enable automatically detecting and classifying the utilities. In parallel, WP3 focuses on a hybridization approach using GPR processing (3D migration and full-wave form inversion) prior to a deep learning process, implemented for high-yield and automatic investigations, as well as utility location and classification. The final WP (WP4) addresses the constitution of various experimental GPR databases to complement the data modeled in WPs 2 and 3 towards developing methodological approaches. These databases will then be demonstrated on: a controlled test site with several homogeneous soils, a full-scale test site offering water table level control, and several actual sites proposed by the St Quentin Metropolitan Water Authority. The use of a commercial step-frequency 3D radar array system and the design of a laboratory multi-antenna radar prototype will also contribute to database compilation in the effort to devise a global methodology of automatic detection, localization and classification. From an economic standpoint, this operational research proposal is part of the industrial partner’s (Logiroad) technical and commercial roadmap, calling for a solution that provides local authorities with access, at all times, to the full set of information characterizing road resources under their purview. The innovation resulting from this project will greatly improve positioning, thanks to a 3D platform regularly updated with information on road surfaces and structures, ancillary facilities and underground networks, in at least three markets, namely: public works contractors, network specifications, and communities seeking to optimize their road assets. To carry out this project, the five partners (including the St-Quentin Authority as an external partner) will be aided by a research engineer, two PhD students and several Master interns.

The ISOLATE project aims at improving the characterization of the liquefaction potential of saturated natural soils and their physical and numerical modelling in order to assess the response of actual geostructures and to reduce the liquefaction hazard (through mitigation) accounting for the current seismic requirements. The academic and industrial teams of the project thus propose: WP1/ the characterization at the scale of the material (cyclic triaxial tests, resonant column, shear box, calibration chamber, in situ pressuremeter), WP2/ the characterization at the scale of the foundation soil and the assessment of scale effects (centrifuge experiments, shaking table tests, innovative laminar boxes), WP3/ the analysis of the effects of liquefaction on structures (physical and numerical modelling), WP4/ to reduce the hazard and assess an innovative mitigation technique (improvement by biocalcification), WP5/ to edit practical recommendations and promote the technical results (database for soil parameters, reference results from physical models, scientific papers, design charts and practical recommendations). WP1: this WP aims at defining the soil parameters for the numerical models as well as the procedures able to characterize the behavior of saturated soils under dynamic excitations (sandy soils with various fine contents). WP2: laboratory tests (centrifuge and shaking table) on a reference sand column characterized in WP1 will be performed. An experimental database will allow to analyze scale effects and to verifying the numerical models for the foundation soil. WP3: this WP aims at: designing interaction tests between the foundation soil and a structure under controlled conditions; validating simulations from experiments; defining reliable proxies to quantify the stability and the damage of structures through performance-based approaches; check simplified criteria for the assessment of the liquefaction hazard with respect to observations. WP4: the efficiency of the mitigation technique (biocalcification) will be assessed from treated physical models (shaking table and centrifuge) with respect to the specifications from WP2 and WP3 and numerical simulations will be performed to model the phenomenon. WP5: the project will propose additional recommendations to the AFPS 2020 working group. It will bring to the engineering community validated assessment tools allowing to reduce the cost of the studies. The consortium of the project is fully relevant since the research partnership involves public research centers (CEA, IFSTTAR), academics (CentraleSupélec, ENPC), private companies (EDF, SolétancheBachy), with complementary expertises and skills in experiments, modelling and geotechnical engineering. The involved research teams have a long experience and a strong know-how in the field of mechanical and dynamic tests on soils and geostructures, and bring their expertise in physical and numerical modelling, in order to improve the knowledge on complex phenomena from the grain scale to the structural scale, as well as engineering practice. Indeed, the contribution to the project of renowned private companies ensures that the economic players will take advantage of the scientific and technical advances: as a hydraulic facilities owner, EDF is able to identify the needs for engineering and to target appropriate promotions; Solétanche-Bachy proposes an innovative mitigation methodology and may use its national and international network to disseminate the results of the project.

Masonry structures are a central preoccupation for infrastructures manager, due to their common presence, their age, with a very high patrimonial and environmental value. Unfortunately they didn’t have benefited of the same efforts in the development of structural analysis tools and standards as concrete or steel structures. The main issue for managers is to quantify the residual bearing capacity of such structure when they are identified as damaged during monitoring campaigns or when they have to be reassessed due to changes in operating conditions. The objective of the Menhir project is to develop a multidisciplinary methodology, dedicated to managers, based on reliable tools for assessing the mechanical and environmental performance of their structures, to ensure preservation and sustainable management.