GEEG Geotechnical & Environmental Engineering Group
L’activité de recherche développée par GEEG est orientée vers le développement de procédures expérimentales, d’essais en laboratoire et d’essais rapides sur site, nécessaires pour accompagner les entreprises, les sociétés d’ingénierie et les producteurs d’agents chimiques dans le développement et la mise en œuvre de projets spécifiques.
GEEG fournit services de Recherche et Développement pour des projets d’ingénierie civile et de l’environnement, avec une attention particulière aux grandes œuvres souterraines et au traitement chimique des sols.
Experimental procedures for the analysis of the injection parameters and the performance of materials and chemicals
GEEG offers services to companies and engineering firms involved in the construction of tunnels using EPB-TBM technology. We provide assistance in the selection of the chemicals, in the modulation of their use, in the assessment of the environmental impact and in the planning of the reuse of the excavated soil.
Over time, GEEG has developed a large number of experimental protocols that can quickly provide the information needed to manage soil conditioning, adapting test procedures resulting from years of research to the client’s needs. The procedures employed for selecting products and dosages to be used in the excavation are developed in the laboratory, thanks to specially designed equipment, capable of reproducing conditions close to those found in the field and adaptable to the characteristics of the TBMs used.
GEEG also provides on-site operational support by developing ad hoc procedures for the analysis of conditioned soil, in addition to the rapid tests well known in the industry literature.
Experimental analyses to evaluate the effectiveness of chemical products and their environmental profile
Chemical companies interested in verifying the characteristics of their commercial products (foaming agents, polymers, backfilling mortar additives, resins, etc.) and evaluating their performance, as well as engineering companies interested in carrying out comparative tests useful for product selection, can rely on GEEG for specific studies and experimental activities aimed at assessing their effectiveness and environmental sustainability.
The services offered include both ad hoc test procedures developed by the Group as part of its soil conditioning research activities and evaluation tests known from the industry literature. These procedures can be carried out using equipment capable of reproducing conditions close to those in the field.
The performance of the products can be assessed in relation to a consolidated technical background and a constantly evolving knowledge framework, selecting the most appropriate experimental approach depending on the intended use of the product and in accordance with the customer’s needs.
IMPACT SUR L'ENVIRONNEMENT
Experimental analyses to assess the environmental impact of chemicals, materials and technological solutions
GEEG assists engineering companies and public administrations by developing experimental protocols for managing the reuse of excavated soil.
The experimental procedures mainly concern the assessment of the biodegradability and ecotoxicity of chemicals commonly used in mechanized excavation, such as foams, polymers, greases, bentonites and cement mix additives.
The equipment available in our laboratories allows the preparation of realistic samples on which, in addition to standard tests, procedures specifically designed to reproduce specific site conditions can be carried out.
CONTRÔLE ET ANALYSE DES DONNÉES
Monitoring activities and data analysis of TBM operations and geotechnical, chemical and environmental aspects
GEEG offers operational support for the management and analysis of mechanized tunnel boring machine data, in real time or a posteriori.
This activity consists in analyzing the parameters recorded by the TBM during excavation, processing them organically, producing reports and proposing operational changes to the TBM’s management in order to improve excavation performance. To this end, GEEG uses a variety of data management tools, from simple spreadsheets to state-of-the-art neural networks.
The expertise acquired by handling and studying a large number of tunnel projects enables GEEG to contribute to the design phase of the work with predictions of excavation timing and performance.
GESTION DES DÉBLAIS
Designing plans for the reuse of excavated soils and rocks and performing the relevant experimental analysis
The reuse of excavated soils and rocks is a key aspect of the design and construction of an underground project which, if properly optimized, can lead to significant technical, economic, environmental and logistical benefits. The vast quantities of excavated soils and rocks, often with excellent chemical/physical/mechanical properties, represent a potential that has only been partially explored yet.
GEEG has developed specific experimental protocols to provide all the information and data necessary for the validation of the project by the competent authorities. The geotechnical, chemical and ecotoxicological analyses, the processing of the results, the preparation of the documentation and the on-site supervision during the execution of the works are carried out in compliance with the regulations in force and according to the specific needs of the client.
BENTONITES ET POLYMÈRES
Experimental analysis of bentonite and polymeric fluids for drilling, micro-tunneling and slurry-shield TBMs
Drilling fluids are aqueous solutions of bentonite and/or polymers used for excavations, such as piles and diaphragms, and for tunnelling with TBMs, micro-TBMs and other no-dig technologies. The main functions of these fluids are to support the borehole, transport excavation debris (bentonite slurry) to the surface and reduce friction between the borehole walls and the excavation tools.
Experimental activities are organized according to the specific needs and drilling technologies used on site and include the execution of geotechnical, rheological and chemical tests.
Determination of the evolution over time of the chemical and physical properties of the conditioned soil
GEEG carries out laboratory activities to assess the degree of biodegradability of conditioning agents in collaboration with contractors and suppliers.
The process of biodegradation is a set of biochemical reactions that lead to the partial or total degradation of organic substances (such as surfactants) through the action of microorganisms present in the environment. In our case, the study is carried out using standardized respirometric tests that allow the evolution of the biodegradation process to be assessed by measuring the biochemical oxygen demand (BOD).
The experimental studies aim to evaluate the influence of conditioning agent dosage, temperature and bacterial inoculum, as well as the effect of soil type in the case of site-specific tests. The tests will also allow to determine at the design stage site-specific storage times for excavated conditioned soils.
Accelerated biodegradation tests are being perfected by GEEG. The results of these tests, obtained by analyzing the kinetic data, can be used to respond rapidly to the needs of the clients.
PERFORMANCES DES TBM
Monitoring, analysis and optimization of TBMs excavation performance
GEEG offers in-depth studies to evaluate the excavation performance of TBMs, with the aim of optimizing the design of the cutterhead and predicting the advance rates and completion times.
The analyses are carried out in accordance with the most advanced prediction models known in the industry literature, using the approach that best suits the information available at the various stages of the project and the client’s needs. In general, the methods used are based on the analytical description of the fracture mechanism of the rock by the cutters or are derived from empirical correlations that take into account the characteristics of the rock by means of indices obtained through specific laboratory tests.
The aim of this activity is both to provide design indications for the choice of certain characteristics of the TBM (number, spacing and type of cutting tools, installed power, etc.) depending on the geotechnical characterization of the rock mass, and to predict the advance speed achievable with a known set of machine parameters.
MORTIERS DE REMBOURRAGE
Experimental analyses to assess and optimize the performance of backfilling grout
Based on the knowledge gained from years of experimentation, GEEG offers services to engineering and chemical companies interested in optimizing backfill grout mix designs or developing additives to achieve specific properties.
The immediate filling of the annular gap between the installed lining and the excavated soil – an operation known as backfilling – is indeed a key element for the successful mechanized excavation of a tunnel. This is usually done by injecting cement mixtures at the tail of the TBM shield.
The experimental activities offered by GEEG allow to evaluate the characteristics of the cement mixes, ensuring that they meet the specific requirements in terms of fluidity, setting time, strength, etc.