SOIL INSTABILITY ON SLOPES IN REGIONS OF PERENNIALLY-FROZEN GROUND

ROAD CONSTRUCTION IN MANY PARTS OF ALASKA NORTH OF THE ALASKA RANGE AND ELSEWHERE IN NORTHERN LATITUDES MUST CONTEND WITH PROBLEMS RESULTING FROM INTENSIVE FROST ACTION AND THE PRESENCE OF PERENNIALLY-FROZEN GROUND. BECAUSE OF POOR DRAINAGE, WET SOILS, DISTURBANCES CAUSED BY REPEATED CYCLES OF FREEZING AND THAWING, AND THE PRESENCE OF A GLIDE PLANE AT THE SURFACE OF THE PERENNIALLY-FROZEN GROUND, SLOPES SUBJECT TO RAPID CREEP ARE MUCH MORE COMMON THAN IN MORE TEMPERATE REGIONS. IN TUNDRA AREAS THE SOIL IS COVERED BY A MAT OF SHALLOW-ROOTED VEGETATION WHICH MODIFIES BUT DOES NOT PREVENT THE CHARACTERISTIC SOIL MOVEMENTS ON SLOPES. SPECIAL PRECAUTIONS MUST BE TAKEN TO COPE WITH THESE CONDITIONS DURING HIGHWAY CONSTRUCTION AND MAINTENANCE. SOIL MOVEMENTS ON SLOPES PRODUCE A SET OF CHARACTERISTIC MICRO-RELIEF FEATURES INCLUDING SOIL TERRACES (SOLIFLUCTION TERRACES, ALTIPLANTATION TERRACES), SOIL LOBES (SOLIFLUCTION LOBES, ZUNGE), PEAT-MOUND STRIPES, PEAT RINGS, TUSSOCK-BIRCH-HEATH STRIPES, ROCK STRIPES, AND SWALES. MANY CONSTRUCTION PROBLEMS ON SEWARD PENINSULA CAN BE ANTICIPATED BY INDENTIFICATION OF THESE FEATURES ALONG PROPOSED ROUTES. RECOGNITION OF THEIR SIGNIFICANCE PERMITS THE FIELD WORKER TO ESTIMATE THE CHARACTER AND DEGREE OF INSTABILITY OF THE SOIL, THE DRAINAGE CONDITIONS, AND THE DANGER OF SUBSIDENCE UPON THAW IN AREAS IN WHICH THESE FEATURES ARE FOUND. IN MANY LOCALITIES, STUDY OF THE MICRORELIEF FEATURES WOULD ASSIST IN SELECTING THE BEST OF SEVERAL ROUTES./AUTHOR/

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  • Accession Number: 00237852
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 26 1970 12:00AM