Soil freezing and frost heaving with special application to roads and railroads

阅读量：

698

作者：

G Beskow

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摘要：

THE TREATMENT OF THE PROBLEM OF FROST ACTION IN SOILS HAS CONSIDERABLE PRACTICAL SIGNIFICANCE IN THE CIVILIZED NATIONS OF THE NORTH TEMPERATE ZONE, WHERE THE WINTERS ARE SO SEVERE THAT FREEZING OCCURS TO CONSIDERABLE DEPTHS. GLACIAL SOILS HAVE A LACK OF COLLOIDAL MATTER, AND A LARGE AMOUNT OF MEDIUM-GRAINED SEDIMENTS, THIS TYPE OF SOIL BEING HIGHLY SUSCEPTIBLE TO FROST ACTION. THE DIFFICULTIES ENCOUNTERED DURING THE MELTING OF THE FROZEN SOIL CONSISTS PARTLY OF THE RESULTING SETTLEMENT OF THE GROUND SURFACE (IMPORTANT FOR RAILROADS AND BUILDINGS), AND PARTLY OF THE LOOSENING OF THE SOIL DURING THAWING WHICH REDUCES THE BEARING POWER OF THE GROUND. THE LOOSENING AND CORRESPONDING REDUCTION IN BEARING POWER IS DUE TO A LARGE INCREASE IN WATER CONTENT OF THE SOIL. THE WATER CONTENT IS INCREASED DURING FREEZING OF FROST HEAVING SOIL BY THE SUCKING UP OF WATER FROM UNDERNEATH, AND ALSO DURING MELTING WHEN THE MELTED WATER FROM THE UPPER LAYERS AND THE RAINWATER FROM THE SURFACE IS PREVENTED FROM DRAINING DOWNWARD BY THE STILL FROZEN LAYERS UNDERNEATH. THUS AN EXCESS AMOUNT OF WATER ACCUMULATES WHEN THAWING OCCURS, WHICH CONSIDERABLY REDUCES THE BEARING VALUE OF THE GROUND. THIS PHENOMENON IS CALLED FROST BOIL. IT IS OF IMPORTANCE THAT IN BOTH FROST HEAVING AND FROST BOILS THERE IS A SUCKING UP OF WATER DURING FREEZING AND THE CONSEQUENT RISING OF THE GROUND SURFACE, AND ALSO THAT DURING THAWING THE BEARING VALUE OF THE ROADWAY IS REDUCED. THE FIRST INVESTIGATOR TO FIND THAT DURING FREEZING OF A FINE-GRAINED SOIL WATER FLOWS TO THE FREEZING LAYERS, INCREASING THE WATER CONTENT, WAS SIMON JOHANSSON, WHO PUBLISHED HIS EXPERIMENTAL RESULTS IN 1914. THE AUTHOR AGREES WITH SIMON JOHANSSON BECAUSE HIS RESULTS SHOW THAT THE AMOUNT DEPOSITED BY EVAPORATION AND CONDENSATION IS INSIGNIFICANT. ON THE BASE OF MANY FIELD AND LABORATORY OBSERVATIONS, A GAS PHASE ALWAYS EXISTS, AND THE TRANSPORTATION IN THE FORM OF VAPOR HAS AN IMPORTANT SIGNIFICANCE, THOUGH THE QUANTITY IS SMALL. THE VAPOR DIFFUSION BETWEEN THE ICE CRYSTALS AND THE SOIL PARTICLES OCCURS OVER A DISTANCE OF 1/100 TO 1/1000MM. THE WATER SUPPLY TO THE FREEZING LAYERS IN FROST HEAVING GROUND COMES PRACTICALLY EXCLUSIVELY FROM CAPILLARY FLOW OF THE WATER BELOW. THE IMPORTANT FACTORS OF THIS PROCESS, WHICH ARE EXTREMELY VARIABLE, ARE THE DISTANCE TO WATER AND SOIL GRAIN SIZE. AN ANALYSIS OF THESE QUESTIONS INCLUDES THE MANNER IN WHICH WATER FREEZES IN SOILS OF DIFFERENT WATER CONTENT AND IN DIFFERENT TYPES OF SOILS.

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关键词：

Roads, Frost damage, Frozen ground, Frost heaving

被引量：

254

年份：

1935