Soil and foundation survey for SNCF Réseau
Tuesday, June 29, 2021
Our teams intervened on these three projects. Their main mission was: the in-depth recognition of the soils and foundations. The goal was to better understand the structures in place and to better apprehend the works to be carried out in the vicinity.
For the LONGUEAU project, the final objective is to reinforce the “OA 10” structure’s banks. The diagnosis of the foundations in place as well as the soils.
Concerning the Ménesvillers project, the creation of a holding pond in the vicinity of a railroad infrastructure required an upstream soil investigation.
Finally, the geotechnical campaign carried out in Calais was part of the regeneration of the Pra Mollien railway bridge. This explains the importance of assessing the foundations and supports of the structure as well as the soil.
These projects are similar in the sense that our teams are working in a complex and sensitive location.
The use of a barge was necessary to carry out the inclined and horizontal drilling in the abutments of the LONGUEAU structure. The drilling machine being on this floating installation, environmental precautions were taken to prevent potential risks of hydrocarbon leakage.
The location near a railroad track makes all drilling operations sensitive. The narrow area of intervention made it difficult to drill at the abutment of the Pra Mollien railway bridge on the canal side.
In Longueau, our teams used two drilling machines (GEO 205 and GEO 105) to carry out core drilling, pressuremetering and destructive drilling. For the drilling on the bridge abutment on the Avre River side, our team on site set up a barge to accommodate the GEO 105. A “hydrocarbon” type pollution recovery system, composed of 2 floating booms and absorbent fabrics, was set up downstream of the barge.
At Ménesvillers, our teams used two drilling machines ( GEO 205 and GEO 105) to carry out core drilling, augering, mini-excavation and pressuremetering.
For the Pra Mollien railway bridge, the narrow zone of intervention, between the abutment and the canal, required the use of a Comacchio MC 400P type drilling machine with a modular hand and rotating in both horizontal directions. Our team performed destructive, pressuremeter and core drilling.
In all three projects, a sludge recovery and treatment system was implemented to reduce the risk of soil and water pollution. In addition, drill parameters such as tool pressure, travel speed, drilling fluid pressure and torque were monitored and saved for each drilling.