Analysis Of The Embankment Stability In Permafrost Regions Based On Strength Reduction Finite Element Method

With the rapid development of economy, a large number of infrastructures, including bridges, roads and railways, are built in permafrost regions. According to the demand of development of road construction and maintenance in permafrost areas, it is extremely urgent to study on the embankment stability in permafrost regions. So far, the research theory of permafrost is relatively abundant, but it needs to be supplemented. Therefore, it is very important to research the stability of embankment in permafrost region. This paper describes the impact of the external environmental factors, internal factors of permafrost, and engineering factors on the stability of embankment in permafrost regions, and analyzes the mechanism of the impact on the stability of embankment under various factors. Considering various factors based on the finite element method to analyze temperature field of embankment under different conditions in permafrost regions. Analyzing the stress-strain field and the stability of embankment under different conditions in permafrost regions based on the finite element double strength reduction method. The main contents and conclusions are as follows.(1)In terms of the characteristics of embankment in permafrost regions, simulating the annual average temperature of-3.82℃, the calescence of climate at a speed of 0.022 ℃ · a-1 constantly, different direction and different altitude of permafrost underlie the embankment during 50 a operating period based on numerical methods. It can conclude that the area of thawing plate underlying embankment, the lowest position of the thawing plate, and the distance deviating from the center line of embankment are the biggest at east-west, 45 ° to the second, north-south minimized. And with the growth of the operating time, the depth and the distance deviating from the center line of embankment and area of the thawing plate are bigger. With the increase of embankment height, the upper limit of permafrost decrease, the area of the thawing plate increases in both horizontal and vertical.(2) Using double strength reduction finite element method to calculate the simplified mechanical model of thawing plate. It can conclude that the stability safety factor of embankment has a turning point with the increases of embankment height under the condition of the given calculation. When embankment is under the height correspond to the point, the safety factor of stability increases with the embankment elevated gradually. When over this height correspond to the point, the safety factor of stability decreases with the embankment elevated gradually.(3) By comparing with the existence of the underlying embankment thawing plate, it can conclude when considering thawing plate the safety factor of stability is lower than the thawing plate is not considered under the condition of the same calculation. By analyzing the state of bilateral and unilateral thawing of the embankment, it can conclude that the safety factor of stability of the bilateral melting is lower than the unilateral melting of the embankment.(4) By analyzing longitudinal deeper development of the thawing plate area, it can conclude that the longitudinal deeper has only impact on the embankment surface with the scale of longitudinal cracks, but has no impact on its position. The deeper the longitudinal dimension of thawing plate, the smaller the safety factor of stability of embankment. The horizontal extended length of thawing plate area of embankment are different, the location and size of longitudinal cracks of the embankment surface are different. There is a critical length in different transverse extended length, and the embankment has the largest cracks.