FROST ACTION THEORIES COMPARED WITH FIELD OBSERVATIONS & DISCUSSION

RECENT INVESTIGATIONS OF THE MECHANISM OF FROST ACTION IN SOILS HAVE INCREASED THE UNDERSTANDING OF THE BASIC NATURE OF THIS MECHANISM. TWO RECENT STUDIES HAVE RELATED THE HEAT FLOW THROUGH THE SOIL SYSTEM TO THE MOISTURE MIGRATION AND THE RESULTING FROST HEAVE. BOTH INVESTIGATORS OBTAINED GOOD CORRELATION BETWEEN THEORY AND LABORATORY EXPERIMENTAL RESULTS, BUT ARRIVED AT SOMEWHAT DIFFERENT CONCLUSIONS. THIS PAPER REPORTS SOME RESULTS OF FIELD OBSERVATIONS ON SUITABLY PREPARED FIELD OBSERVATION PLOTS. ALTHOUGH THESE OBSERVATIONS WERE MADE WITH A VIEW TOWARD EXPLORING SEVERAL ASPECTS OF FROST ACTION, ONLY THE RELATIONSHIP OF THE HEAT BALANCE TO HEAVING AND PENETRATION IS DISCUSSED. MEASURED HEAVE RATES WERE COMPARED WITH ESTIMATED HEAT FLOW RATES FOR THE CONDITION OF ZERO PENETRATION RATE. ALTHOUGH THERE ARE VARIATIONS IN THE BEHAVIOR OF THE FOUR SOILS EVALUATED AND VARIATIONS BETWEEN SEASONS, FIELD OBSERAVTIONS AGREE WELL WITH THEORETICAL PREDICTIONS. FOR THE CASE OF A PENETRATING FROST LINE, NEITHER OF THE CONFLICTING CONCEPTS CAN BE VERIFIED COMPLETELY. ON THE BASIS OF THE LIMITED DATA AVAILABLE, IT APPEARS THAT THE VALIDITY OF EITHER CONCEPT DEPENDS ON THE SOIL TYPE. /AUTHOR/