INFLUENCE OF FROST ACTION ON THE BEARING CAPACITY OF SOILS

DURING FROST MELTING PERIODS, THE BEARING CAPACITY OF FROST-SUSCEPTIBLE SUBGRADE SOIL OR SUBBASE MATERIAL IS REDUCED. THE MAGNITUDE OF THIS REDUCTION IN BEARING CAPACITY CAN BE DETERMINED BY PERFORMING CBR TESTS ON SOIL SAMPLES SUBJECTED TO SEVERAL FREEZE-THAW CYCLES. FUTHER STUDIES ARE NECESSARY BEFORE THE PREFROZEN CBR VALUES CAN BE DIRECTLY INTRODUCED IN ROAD DESIGN AS A CHARACTERISTIC NUMBER FOR BEARING CAPACITY. THE PROPOSED TEST PROCEDURE CAN BE USED FOR TESTING ALL SOILS TYPES EXCEPT CLAYS AND IS PARTICULARLY USEFUL FOR DIRTY SANDS AND GRAVELS. FOR THESE SOIL TYPES, THE CBR VALUE AFTER SEVERAL FREEZE-THAW CYCLES IS CONTROLLED BY THE FRACTION OF PARTICLES SMALLER THAN 0.02 MM AND THE COEFFICIENT OF UNIFORMITY. THE CASAGRANDE FROST CRITERION CAN PERHAPS BE MODIFIED TO INCLUDE THE COEFFICIENT OF UNIFORMITY. /AUTHOR/