Temperature regime of soil massives as a geological influence on the founding of buildings

Abstract

The study was performed in order to develop a method for determining the calculated values of the temperature of soil massives of the buildings foundations based on the results of meteorological observations, as well as analysis of their changes in depth and territory. For the analysis the generalized results of measurements of soil temperature on depth up to 3.2 m, which were carried out by deep thermometers at 11 meteorological stations from different areas of Ukraine are used.

It is established that with increasing depth, seasonal changes in soil temperature attenuate and lag behind in time from changes in air temperature and soil surface. Standard deviations of soil temperature do not have a pronounced seasonal variability, but systematically decrease with increasing depth.

The probabilistic method of determining the design values of soil temperature is developed on the basis of the description of average minima and average maxima of temperature in the form of sequences of normally distributed random variables corresponding to 12 months of the year. According to the data of 11 selected meteorological stations of Ukraine, the minimum and maximum design values of soil temperature for depths up to 3.2 m and return periods of 20…200 years have been determined. Insignificant dependence on the return periods allowed to take as calculated data the value of soil temperature, which correspond to a return period of 100 years.

Dependences of minimum and maximum design values of soil temperature on depth for 11 meteorological stations of Ukraine are described by analytical expressions of exponential type. By analyzing these expressions, it was found that at a depth of 8…13 m, the minimum and maximum design values of soil temperature approach +12…+18°С and remain unchanged throughout the year.

The obtained results allow to predict the probable limits of soil temperature change at different depths and can be used when performing thermal calculations of deep rooms and when assessing the force effect of temperature on underground structures.