RESULTS OF GEOLOGIC RESEARCH AT THE STRAIGHT CREEK TUNNEL PILOT BORE, COLORADO

PROJECTION OF DETAILS OF SURFACE GEOLOGY TO DEPTH PRIOR TO CONSTRUCTION HAS MET WITH ONLY LIMITED SUCCESS IN MANY TUNNELING OPERATIONS. IN THE RESEARCH PROJECT ON THE STRAIGHT CREEK TUNNEL PILOT BORE, HOWEVER, GOOD RESULTS WERE OBTAINED BY THE PREDICTION, BASED ON A STATISTICAL STUDY OF SURFACE AND DRILL-HOLE FEATURES, OF THE KINDS OF CONDITIONS AND THEIR EXTENT, BUT NOT THEIR EXACT LOCATIONS, THAT COULD BE EXPECTED AT TUNNEL LEVEL. SUCCESSFUL PREDICTIONS WERE MADE REGARDING PERCENTAGES OF ROCK TYPES, LINEAR FEET OF FAULTED AND SHEARED ROCK, AND ATTITUDES OF FOLIATION AND FRACTURES, INCLUDING FAULTS AND JOINTS. PREDICTED ROCK LOADS AND FINAL SWELL PRESSURES IN GOUGE AND ALTERED ROCKS AGREED WELL WITH ACTUAL MEASUREMENTS. GROUND-WATER FLOWS WERE ENCOUNTERED IN EXPECTED AMOUNTS, BUT CRITERIA FOR ESTIMATIONS PROVED TO BE UNSOUND. ESTIMATES WERE MADE OF THE AMOUNT OF TEMPORARY SUPPORT, FOOTAGE OF FEELER HOLES, AND THE AMOUNT OF GROUTING THAT WOULD BE RE REQUIRED, THESE PROVIDED A SOUND BASIS FOR ESTIMATES, BY ENGINEERS, OF TUNNEL COSTS. /AUTHOR/

Language

  • English

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 9-19
  • Monograph Title: Tunneling, geophysical studies and soil-culvert interactions
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00228831
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 2004 2:37AM