SETTLEMENT PERFORMANCE OF TWO EMBANKMENTS ON DEEP COMPRESSIBLE SOILS

THE AUTOROUTE DE LA RIVE NORD ON THE NORTH SHORE OF THE ST. LAWRENCE RIVER TRAVERSES DEEP DEPOSITS OF COMPRESSIBLE SOILS IN THE BERTHIERVILLE ARE. WHERE THE FOUR-LANE AUTOROUTE SPANS A RAILROAD SPUR LINE AND HIGHWAY 41, THE UPPER 60 FT (18 M) OF SUBSOIL CONSISTS OF LAYERS OF SILTY SAND, SILTY CLAY, SAND AND SILT, STRATIFIED SILTY CLAY AND SAND, AND OVERLIES 182 FT (55 M) OF MARINE CLAY. THE DISTANCE BETWEEN THE RAILWAY AND HIGHWAY 41 IS 400 FT. (120 M), AND THE OVERPASSES ARE CONNECTED BY A GRANULAR FILL. THIS FILL HAS A TOTAL HEIGHT OF 35 FT (10.7 M), AND, FOR STABILITY REASONS, REQUIRED STAGE CONSTRUCTION AND STABILIZING BEAMS. A 25 FT (7.6 M) TEMPORARY PRELOADING FILL WAS ALSO PLACED ON HIGHWAY 41 TO INCREASE THE SHEAR STRENGTH OF AN UNDERLYING UPPER CLAY LAYER AS REQUIRED FOR STEEP SLOPE DESIGN AT THE OVERPASS ABUTMENTS. LABORATORY TESTING INDICATED THAT THE UPPER 60 FT (18 M) OF THE FOUNDATION SOILS ARE NORMALLY CONSOLIDATED FLUVIAL DEPOSITS AND THAT LARGE SETTLEMENTS OF THE EMBANKMENTS WERE TO BE EXPECTED. THE LOWER MARINE CLAY IS OVERCONSOILDATED BY 0.8 TON/FT SQUARE (0.8 KG/CM SQ). PERIODIC OBSERVATIONS TAKEN SINCE THE BEGINNING OF CONSTRUCTION IN 1964 SHOW THAT THE AUTOROUTE EMBANKMENT HAS SETTLED 7.4 FT (2.26 M) AND THAT SETTLEMENT IS CONTINUING AT A GRADUALLY DECREASING RATE. DEEP SETTLEMENT GAUGES AND PIEZOMETERS SHOW THAT MOST OF THE SETTLEMENTS ARE DUE TO THE CONSOLIDATION OF THE UPPER 60 FT (18 M) OF SOIL. THE LOWER MARINE CLAY IS CONSOLIDATING AT A MUCH LOWER RATE AND WILL CAUSE SETTLEMENTS FOR MANY YEARS. ANALYSIS OF FIELD OBSERVATIONS DEMONSTRATES THAT THE MEASURED SETTLEMENTS ARE ATTRIBUTED TO THE PRIMARY CONSOLIDATION OF THE COMPRESSIBLE STRATA RESULTING FROM THE DISSIPATION OF PORE PRESSURE. IN GENERAL, THE MEASURED SETTLEMENTS COMPARE FAVORABLY WITH THE PREDICTIONS ON LABORATORY TESTS. FIELD AND LABORATORY SOIL PROPERTIES ARE ALSO COMPARED. THIS PAPER PRESENTS A DETAILED RECORD OF THE LABORATORY INVESTIGATION AND FIELD OBSERVATIONS MADE IN CONJUCTION WITH THE CONSTRUCTION OF THE PERMANENT AUTOROUTE EMBANKMENT AND THE TEMPORARY PRELOADING FILL. EXTENSIVE FIELD STUDIES ON NEGATIVE SKIN FRICTION ON PILES HAVE BEEN CONDUCTED AT THE SAME SITE, AND THE RESULTS HAVE BEEN REPORTED ELSEWHERE.

• Authors:
  • SAMSON, L
  • Garneau, R
• Publication Date: 1905

Media Info

• Features: Figures; Photos; References; Tables;
• Serial:
  • CANADIAN GEOTECHNICAL JOURNAL
  • Volume: 10
  • Issue Number: 2
  • Publisher: National Research Council of Canada

Subject/Index Terms

• TRT Terms: Clay; Consolidation; Embankments; Fills; Foundation soils; Four lane highways; Granular materials; Marine clays; Piezometers; Pore pressure; Sand; Shear strength; Silts; Slope stability; Slopes; Soil stabilization; Soils; Stability (Mechanics); Stratification
• Uncontrolled Terms: Soil consolidation
• Old TRIS Terms: Consolidation rate; Embankment stability; Settlement rate
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00230995
• Record Type: Publication
• Source Agency: Roads & Transportation Assoc /Canada
• Files: TRIS
• Created Date: May 15 1996 12:00AM