PROBLEMS OF ROCK MECHANICS ENCOUNTERED DURING THE CONSTRUCTION OF THE MONT-BLANC TUNNEL /IN FRENCH/

DURING THE DRILLING OF THE MONT-BLANC TUNNEL, EXTENSIVE BOLTING OF THE VAULT HAD TO BE CARRIED OUT BECAUSE OF DECOMPRESSION. DECOMPRESSION PHENOMENA ARE CONNECTED TO THE PRESENCE OF INITIAL STRESSES OCCURRING AT GREAT DEPTH IN THE ROCK MASS. THE CONCENTRATION OF STRESSES CAUSED BY EXCAVATIONS RESULTED IN VIOLENT RUPTURE OF THE ROCK ON THE WALLS OF THE TUNNEL. THE FOLLOWING STUDIES WERE CONDUCTED: STUDY OF THE RELATIONS BETWEEN CRACKING OF THE ROCK AND FRACTURE OF THE ROCK MASS, LABORATORY TESTS ON THE MECHANICAL BEHAVIOUR OF THE PROTOGIN, DYNAMIC NONDESTRUCTIVE TESTING OF THE ROCK MASS BY MEANS OF SEISMIC REFRACTION SURFACE MEASUREMENTS OR MEASUREMENTS IN BORE-HOLES OR BETWEEN TWO BORE-HOLES, MEASUREMENTS OF STRESSES IN HORIZONTAL BOREHOLES PERPENDICULAR TO THE AXIS OF THE GALLERY SHOWING THE STRESS CONCENTRATION IN THE VICINITY OF THE GALLERY AND FACILITATING THE DETERMINATION OF INITIAL STRESSES AT 3 DIFFERENT POINTS AND OBSERVATIONS AND ANALYSIS OF PARTICULAR PHENOMENA OCCURRING IN CORE-SAMPLES OBTAINED DURING THE DRILLING OF ROCK UNDER HIGH STRESS. THE TUNNEL LINING WAS SUBJECT TO INTENSIVE CRACKING. TESTS SHOWED THAT THESE CRACKS WERE NOT CAUSED BY STRESSES TRANSMITTED BY THE ROCK MASS BUT BY HYGROMETRIC AND THERMAL SHRINKAGE. /LCPC/(A)/RRL/

  • Supplemental Notes:
    • No 42, pp 115-145, 16 FIG, 13 TAB, 14 PHOT, 12 REF
  • Authors:
    • Panet, M
  • Publication Date: 1969-12

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Filing Info

  • Accession Number: 00234843
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Apr 25 1971 12:00AM