Tunnels and underground constructions
- General contractor :GRT Gaz
- Assignment: Execution Study G3
- Total cost of work: €34k excluding tax
- Completion date: 2014-2015
PROJECT DESCRIPTION AND CHARACTERISTICS
The study carried out by GEOS Ingénieurs Conseils constitutes a part of the installation of a gas pipe Ø 1200 between the communes of Cuvilly and Betz in the department of Oise. The pipeline crosses SNCF tracks underground at five points in the communes of Rouvillers, Houdancourt, Rully, and Ormoy-Villers.
The technique used for the five crossings is the use of a micro-tunneler in lengths of about 40m and at depths between 4 and 6m.
ASSIGNMENT
GEOS’s mission was to carry out partial geotechnical Design Studies (G3 within the meaning of the NF P 94-500 standard of November 2013) for five underground crossings of SNCF tracks, using a micro-tunneler. These studies addressed, in particular, the following points:
- Analysis and synthesis of available geotechnical data,
- Identification of the hazards and geotechnical constraints of project implementation,
- Definition of the principles of preparatory work to be carried out before execution,
- Study of the influence of digging on SNCF tracks: estimation of settlement with an analytical method and of finite element with a numerical method,
- Analysis of the construction conditions and dimensioning of the foundations of the isolating stations,
- Calculation of the settlements induced by the drawdown of the groundwater on the level of the SNCF tracks,
- Definition of excavation solutions to limit the impact on the tracks.
