Caractérisation mécanique de la plateforme ferroviaire par ondes sismiques de surface

The renewal of existent railways requires the characterisation of the mechanical properties of railway platforms  (RP),  thus  raising   the  need  to  select  appropriate  maintenance  actions. Conventional techniques (geotechnical soundings, coring) remain local, destructive, expensive and with low yields. Using  non-destructive investigation  techniques  for local  diagnosis  and  monitoring  thus appears  of great interest for enhancing RP control. Seismic surface-wave methods have been proposed to estimate in situ  mechanical   parameters  of  the  superficial  layers  below  railways.  In  this context,  a  joint geotechnical and seismic survey was carried out along the Northern Europe high-speed line (LGV) in order to precisely determine the origins of a phenomenon affecting the geometry of the track. Strong a priori knowledge  of  the  RP  structure  allowed  for inverting dispersion  measurements  for  1D  VS models along the track.

The results showed a contrast of VS in the loess lying below the RP, between areas  where  the  phenomenon  was  observed  and  those  it was  not.  This  contrast  was  confirmed  by Bender Elements measurements of VS performed on core drilling samples, and corresponded to the lateral  variations  observed  along  the  track.  These results   encourage  considering  dispersion measurements as an appropriate tool of RP monitoring.

Ludovic Bodet
Convention SNCF / UPMC
Durée du projet: 
3 ans
Date de début: 
mar 2013
Date de fin: 
déc 2016
Hydrogéologie Physique