An experimental study of a forced ventilation pile

Abstract

Introduction. Thermal stabilization of foundation soils is a most widely spread method of engineering protection of structures in the cryolithic zone. Presently, as a rule, any construction is feasible if the footing temperature remains negative in the regions that have permafrost soils. In the article, the co-authors have analyzed a conceptually new method of thermal stabilization of soil, that is, the application of forced ventilation piles. The goal of the laboratory experiments is to simulate the frozen soil behaviour in case of its exposure to a ventilated and cooled pile. The co-authors have solved the problem of soil temperature reduction to ensure the soil transition from the thawed state into the frozen or plastic frozen state. Besides, the co-authors have substantiated the efficiency of this thermal stabilization method. The subject of this research is a ventilated pile, driven into sandy soil and ventilated by the cool air generated by the refrigerating unit.
 Materials and methods. A laboratory study of a scaled model.
 Results. According to the data provided by the temperature sensors, a forced ventilation pile kept the soil frozen in the radius of 10 cm as of the end of the second winter, which means 2 meters, given the scale factor of the experiment. This methodology can also be applied as a method of thermal stabilization and refrigeration of soils. In the course of the experiment, thawed soil froze. In summer, the seasonal active soil layer thawed, and negative temperatures remained unchanged and generated a frost table registered by the temperature fields, used in the summer period.
 Conclusions. Soil remains frozen in summer; the bearing capacity of the pile remains unchanged.
 Acknowledgements: The co-authors would like to express thanks to the Central research and development laboratory of permafrost research of the Federal State Budgetary Educational Institution of Higher Education Tyumen Industrial University, and to anonymous reviewers.