FIELD TESTS ON BEARING CAPACITY, SHEARING AND PENETRATION RESISTANCE OF SOILS

THE FIRST PART CONTAINS THE RESULTS OF FIELD SHEAR TESTS MADE ON DIFFERENT COMPONENTS OF FLEXIBLE TYPE ROAD STRUCTURES, DURING THE PAST YEAR. THE FOLLOWING PRACTICAL FACTORS ARE DISCUSSED: (1) PROPER "SEASONING" OF BASES FOLLOWING CONSTRUCTION, (2) DETERMINATION OF THE CAUSES OF FAILURE, (3) SURCHARGE EFFECT OF OVERLYING LAYERS AS FACTORS OF SAFETY IS DESIGN, AND (4) THE RELATIONSHIP OR ARBITRARY SELECTED SOIL FACTORS TO THE STABILITY OF UNCONFINED COHESIVE SUBGRADES. IN THE SECOND PART A METHOD FOR OBTAINING THE BEARING CAPACITY OF THE ROAD STRUCTURE OR ANY OF ITS INDIVIDUAL COMPONENTS IS DESCRIBED AND THE RESULTS OBTAINED ARE DISCUSSED. THIS METHOD UTILIZES THE ANCHORAGE OBTAINED BY PLACING AN AUGER IN THE SOIL TO A SUITABLE DEPTH. THE REQUIRED REACTIVE FORCE FOR DETERMINING THE BEARING CAPACITY OF THE SOIL IS PROVIDED BY OPERATING THE HYDRAULIC JACK OF THE SHEAR MACHINE AGAINST A HORIZONTAL BEAM ATTACHED TO THE UPPER PART OF THE ANCHORED AUGER SYSTEM. RELATIVELY SMALL CIRCULAR BEARING PLATES OF DIFFERENT AREAS ARE RECOMMENDED FOR USE. THIS METHOD OBVIATES THE USE OF LOADED TRUCKS OR OTHER UNWIELDY VEHICLES IN OBTAINING BEARING TEST DATA. THE REPORT ALSO CONTAINS A DESCRIPTION OF A PENETROMETER AND A BRIEF DISCUSSION OF THE RESULTS OBTAINED FROM TESTS ON COHESIVE SOILS IN THE FIELD. THE DEVELOPMENT OF THE LATTER TWO TEST METHODS ARE NOT COMPLETE BUT ARE DESCRIBED AT THIS TIME IN THE HOPE THAT OTHERS MAY WANT TO USE THEM OR A MODIFICATION OF THE PRINCIPLES INVOLVED. THE REPORT CONCLUDES WITH A SUGGESTION THAT AN EXTENSIVE FIELD STUDY OF COHESIVE SOILS BE MADE IN WHICH THE SHEARING, BEARING CAPACITY AND PENETRATION METHODS BE EMPLOYED SIMULTANEOUSLY AND THE RESULTS COMPARED. ALSO THAT A CORRELATION OF THESE TESTS BE MADE WITH THE LABORATORY STABILOMETER METHOD. FROM SUCH A STUDY A MINIMUM STANDARD FOR A SUITABLE SUBGRADE COULD BE ESTABLISHED AND THUS AFFORD A QUANTITATIVE BASIS FROM WHICH THE EFFECT OF ANY SUBGRADE TREATMENT OR IMPROVEMENT COULD BE MEASURED AND COMPARED. FURTHERMORE IT WOULD ESTABLISH THE MOST PRACTICAL AND EFFECTIVE MEANS OF GETTING ACTUAL FIELD DATA TO USE IN THE EXISTING DESIGN FORMULAS FOR FLEXIBLE PAVEMENTS. /AUTHOR/

  • Supplemental Notes:
    • Vol 20, pp 287 - 298, 16 FIG, 1 TAB
  • Authors:
    • Burggraf, F
  • Publication Date: 1941

Media Info

  • Monograph Title: Proceedings of the Twentieth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 3-6, 1940
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00233057
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM