Open AccessInsights on squeezing behavior from Saint-Martin-la-Porte galleries
Author(s) -
Yixuan Liu,
Jean Sulem,
Didier Subrin,
Huy Tran-Manh,
Emmanuel Humbert
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/833/1/012105
Subject(s) - context (archaeology) , saint , excavation , closure (psychology) , deformation (meteorology) , anisotropy , geology , instability , carboniferous , archaeology , geotechnical engineering , computer science , physics , history , geomorphology , mechanics , law , paleontology , optics , political science , oceanography , structural basin , computer security
In the context of the Saint-Martin-la-Porte survey project of the Lyon-Turin railway link, an access gallery (SMP2) was first excavated across a Carboniferous formation, where tectonized productive Houiller was met at a depth of 300 m. It exhibited a highly squeezing behavior, characterized by large, time-dependent and anisotropic deformation. Recently, a new survey gallery (SMP4) began to be excavated along the axis of the future base tunnel at a depth of about 600 m. Squeezing conditions have been met again when SMP4 crossed the same Carboniferous formation. Practical problems have been encountered related to the large and anisotropic closure of the cross-section and the instability on the tunnel face. On the basis of previous studies and numerical analyses of carried out for SMP2, the proposed methods are extended to SMP4 conditions. Numerical modeling is performed using FLAC3D code and the various phases of excavation and specific support installation are considered. The efficiency of the compressible elements in reducing the stress in the support system is demonstrated.