CORRECTION OF AN EMBANKMENT FOUNDATION FAILURE AT THAMA ROCKS, IDAHO

DURING CONSTRUCTION OF A PORTION OF SH-200 ALONG THE PEND OREILLE RIVER IN NORTHERN IDAHO AN EMBANKMENT FOUNDATION REACTION TO THE LOAD IMPOSED BY A 40 FT ROCK FILL RESULTED IN APPRECIABLE DISTRESS TO THE ADJACENT RAILROAD. ADDITIONAL SUBSURFACE INVESTIGATION, EXTRAPOLATED DATA FROM AN ADJACENT FULLY-INSTRUMENTED EMBANKMENT FOUNDATION WAS USED TO EFFECT A DESIGN FOR A STABILIZING BERM. CONSTRUCTION PROCEEDED TO COMPLETION IN JANUARY, 1971. DURING A PERIOD OF ABNORMALLY HIGH SNOW MELT AND PRECIPITATION, GENERAL FAILURE OF THE EMBANKMENT FOUNDATION DESTROYED A PORTION OF THE COMPLETED ROADWAY AND CAUSED SUFFICIENT DISTORTION TO THE RAIL ROADBED TO RESTRICT TRAIN TRAFFIC. DATA DEVELOPED FOR THE INITIAL CORRECTION WAS RE-EVALUATED, BUT ONLY BY USING EXTREMELY HIGH VALUES OF SEEPAGE PRESSURE (OR UNREALISTICALLY LOW SOIL STRENGTH PARAMETERS) COULD THE OBSERVED FAILURE BE MOLDED. CORRECTION PROCEDURES WERE BASED ON THE BEST FIT MODELS AND INCLUDED: 1. FILL LOWERING, 2. ALIGNMENT SHIFT, 3. FILL SLOPE FLATTENING, 4. ADDITIONAL BERM CONSTRUCTION 5. GROUND WATER CONTROL 6. SURFACE WATER CONTROL DURING JANUARY OF 1972, GROUND WATER CONDITIONS NEARLY AS SEVERE AS THOSE WHICH CAUSED THE 1971 FAILURE PRODUCED TEMPORARY DEFLECTION IN THE INCLINOMETER WELLS, BUT NO APPARENT SURFACE DISTORTION. /AUTHOR/

Media Info

  • Features: Figures;
  • Pagination: p. 151-64

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Filing Info

  • Accession Number: 00236440
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 4 1973 12:00AM