Technical Measures for Limitation of Frost Depth in Soil

Renovation processes of existing buildings, including historically protected ones, are most of the time focused on energy saving. Nonetheless these processes might affect the function of existing shallow foundations. This paper deals with the influence of soils moisture content onto the depth of freezing. The depth of freezing depends on the type of soil as well, not just the moisture content. The influence of water and soils composition are generally perceived to be substantial for depth of freezing. Sub-zero temperatures do significantly change the soils characteristics, which has an effect to the building structure. The purpose of the research done by the personnel of Brno University of Technology was to determine the effects of special measures against frost penetration of soil. These measures included the application of various materials and solutions over the terrain in winter to monitor frost depth of soil.

A frost heave model of unsaturated coarse-grained soil considering vapour transfer

Substantial frost heave has been observed in coarse fills in high-speed railway embankments. These coarse fills have low fine contents and very low water content. The groundwater table is located below the coarse fills. The coarse fills were considered not susceptible to frost heave. Recent experimental results in the literature showed that vapour transfer has a considerable influence on the frost heaving of unsaturated coarse-grained soil. But vapour transfer has been rarely considered in the modelling of frost heave. This study presents a new frost heave model with considering vapour transfer and its contribution to ice formation. The rigid ice theory is applied to initiate an ice lens formation in the frozen fringe. An updated computer programme PCHeave is developed by considering the vapour transfer. The results of the proposed model are compared with laboratory test results, which show reasonable agreement. The prediction of the model agrees well with the measured frost heave and frost depth, which indicates that the proposed model can reasonably reflects the process of frost heave in unsaturated coarse soil.