Stochastic Thermal-Mechanical Characteristics of Frozen Soil Foundation for a Transmission Line Tower in Permafrost Regions

Abstract

The Qinghai–Tibet Power Transmission Line (QTPTL), crossing about 55 km of permafrost region, was constructed between July 21 and October 211. The long-term thermal-mechanical stabilities attract extensive attention because of global warming and engineering activities. Conventional calculation and prediction of the thermal-mechanical characteristics of a frozen soil foundation for the QTPTL always involve deterministic analysis. This study aimed to investigate the uncertain thermal-mechanical characteristics of a transmission tower foundation by a stochastic analysis method. Considering the effect of stochastic temperature on the stochastic deformation, a stochastic coupling computer program was compiled. The random temperature fields and random deformation fields of foundation soils for a transmission line tower in a permafrost region were calculated and predicted for the next 3 years. This work provides a novel method to analyze the stochastic thermal-mechanical characteristics of a frozen soil foundation for a transmission line tower in permafrost regions. The average standard deviations of temperature grew from 1.1 to 1.6°C on January 15, and the maximum standard deviations of temperature were grew from 3. to 3.5°C. The average standard deviations of vertical displacement grew from .46 to .79 cm on January 15, and the maximum standard deviations of vertical displacement grew from 1.81 to 21.2 cm. The increase of standard deviations implies that the results of conventional prediction methods for temperature and deformation may be deviate from the exact value. These results can clarify the stochastic thermal-mechanical characteristics of frozen soil foundations for the QTPTL in permafrost regions.