Snowcover effect in open crawl space on temperature conditions of subgrade soils

Abstract

At building design stages in permafrost conditions, it is important to conduct thermal analysis to assess temperature changes in the operation of subgrade soils. In calculations, geological factors are considered, such as lithological structure, physical and thermal characteristics of soils, geocryological (rock temperature) and climatic (ambient temperature, wind speed, height and density of snowcover). The snowcover height has a significant impact on soil freezing in winter. Existing requirements are not often satisfied for clearing blown snow in the open crawl space, that requires consideration of changes in geocryological conditions. For buildings with open crawl space, the snowcover height depends on the building dimensions, however, the principles for changing the height are not standardized. Since the results of thermal engineering calculations are used to select the parameters of pile foundations and determine their load-bearing capacity, it is necessary consides factors influencing the calculation results of thermal engineering.Purpose: The aim of this work is to determine the most reliable way to specify snowcover in the open crawl space to predict thermal calculations.Methodology/approach: Different snowcover types are for considered for structures with the open crawl space with the plan dimensions over 3 m and for vertical tanks of a diameter 25 m. Thermotechnical calculations and verification with geotechnical monitoring data are carried out.Research findings: It is shown that the snowcover height affects the calculation results, when using different methods of snow drifting. The temperature difference at the same depths and at depths below 11 m is insignificant for all types of subgrade soil. The definition methods are determined for the snowcover, that have the highest correlation with the real temperature of the subgrade soil.