Research on geotechnical properties of frost heaving soil hazards on foundations in Ulaanbaatar area of Mongolia

The duration of winter cold season on territory of Mongolia lasts considerably long period of time during which the temperature on surface can reach -25-45°C causing frost heaving process to occur in the deep freezing soil. The phenomenon of frost heave results in the uplift of low embedded foundations during freezing period and settlement during spring thawing. These upward and downward motions induced by freezing and thawing cycles can be pointed as a main cause of structural damages in Mongolia. The research to determine the magnitude of frost heaving forces, the location and depth where the heave occurs most intensively, and measures to be taken to avoid frost heave induced damages was conducted at experimental field located at 7^th microdistrict of Ulaanbaatar city. For this purpose frost heave force measuring special device was designed and successfully tested at experimental field and it was found that the frost heaving forces reach its highest value (up to 2.8 MPa) at 1.0-1.5 m depth. Based on the research results the new methodology to determine frost heaving forces along with detailed analysis of heaving process was performed to avoid frost heave caused damages to structures and some recommendations are provided to address the construction safety concerns.