FACTORS OF SAFETY TO BE APPLIED IN THE UTILIZATION OF SHEAR TEST DATA

THE IMPORTANT PROBLEM IS COMPLETELY AND ACCURATELY TO DETERMINE THE SHEARING CHARACTERISTICS OF THE SOIL. CAREFUL CONSIDERATION MUST BE GIVEN TO THE METHODS OF SHEAR TESTING AND THE ANALYSIS AND INTERPRETATION OF TEST RESULTS. RECENT RESEARCHES BY LEADING AUTHORITIES IN THE FIELD OF SOIL MECHANICS HAVE GIVEN US CERTAIN FUNDAMENTAL PRINCIPLES. THE ULTIMATE SHEARING FAILURE IN SOIL GOVERNED BY THE EFFECTIVE STRESSES CARRIED ENTIRELY BY THE GRAIN STRUCTURE OF THE SOIL. A SUBSTANTIAL PART OF THE TOTAL APPLIED STRESSES MAY BE TEMPORARILY CARRIED BY HYDROSTATIC STRESS IN THE PORE WATER, WHICH DOES NOT CONTRIBUTE IN ANY WAY TO MOBILIZING SHEARING STRENGTH. THE PROPORTION OF THE TOTAL APPLIED STRESSES THAT IS EFFECTIVE DEPENDS UPON THE RELATION BETWEEN SHEARING STRESS AND THE VOLUME-CHANGE THAT ALWAYS ACCOMPANY SHEARING DEFORMATIONS. THE SHEARING CHARACTERISTICS ARE INTIMATELY RELATED TO CONSOLIDATION CHARACTERISTICS, AND ARE DETERMINED BY THE INITIAL VOIDS RATIOS AND THE LOAD HISTORY BY WHICH THIS INITIAL CONDITION HAS BEEN REACHED. THE SHEARING CHARACTERISTICS OF CERTAIN COHESIONLESS AND CERTAIN COHESIVE PLASTIC SOILS, BOTH IN THE REMOLDED AND UNDISTRUBED STATES, ARE GIVEN IN SOME DETAIL, AND ARE DISCUSSED IN RELATION TO SHEAR FAILURE PHENOMENA. THE RESULTS ARE ANALYZED AS TO VALUES TO BE USED IN THE ANALYSIS AND SOLUTION OF PRACTICAL PROBLEMS. /AUTHOR/