FAILURE PATTERNS IN A ROCK CUT RESTING ON CLAY

A 30M-HIGH ROCK CUT WAS EXCAVATED AT A SIDEHILL FOR THE PREPARATION OF A PLOT WHERE A BUILDING WAS TO BE CONSTRUCTED. THE BOTTOM OF THE EXCAVATION REACHED A THICK CLAY LAYER AND IN SOME PLACES IT PENETRATED 1 TO 2M INTO THE CLAY LAYER. THE CLAY SAMPLES OBTAINED SHOWED THAT LIMIT EQUILIBRIUM CONDITIONS MIGHT BE ATTAINED WHERE THE CLAY WAS NOT PENETRATED AND THAT FAILURE WOULD OCCUR WHERE THE EXCAVATION WAS CARRIED DOWN INTO THE CLAY LAYER. THIS IS BASED ON THE ASSUMPTION THAT THE ROCK LOAD IS FLEXIBLE. BUT SINCE THIS IS NOT THE CASE, LOCAL FAILURES WERE OBSERVED AT THE FOOT OF THE ROCK. NO GENERALIZED FAILURE OF THE ROCK MASS OCCURRED. THIS WAS DUE TO THE FACT THAT THE ROCK LOAD WAS REDISTRIBUTED TOWARDS THE HARDER SPOTS AND TO THE INTERIOR OF THE MASS. CAVITIES FILLED WITH THE LOOSENED BLOCKS APPEARED. IN OTHER INSTANCES ROCK PARTICLES FAILED AT THE FOOT. IN ORDER TO PREVENT FURTHER DAMAGE, TWO DIFFERENT SOLUTIONS WERE PROPOSED: (1) CONSTRUCTION OF A ROW OF CONCRETE PILES AT THE FOOT OF THE SLOPE ANCHORED TO THE ROCK. (2) OVERLOADING OF THE FOOT BY MEANS OF HEAVY CONCRETE BLOCKS ALSO ANCHORED TO THE ROCK. /RRL/

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 237-42

Subject/Index Terms

Filing Info

  • Accession Number: 00235244
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: Apr 23 1972 12:00AM