Road pavement operating conditions in spring in areas with deep seasonal soil freezing

Road pavements of highways in Russia are designed for the spring period of their operation — the period of the highest soil dampness. During this period, when air temperature is above 0°C, thawing of the seasonally frozen soil layer under the pavement begins. As a result of dampness, the strength characteristics of the soil in this layer of the roadbed will change downward, i.e. will be less than those assumed in the calculation of the pavement. This road structure condition will continue until the seasonal permafrost has completely degraded. During the thawing of the seasonally roadbed frozen layer, the vehicle load distribution pattern will not correspond to the design one, where the roadbed will consist of two layers — thawing and still frozen. Only after complete thawing of the frozen layer in the roadbed, its design scheme will correspond to the initial design scheme. This paper’s research purpose is to analyze the state of the road structure, in which it’s operating not in a state corresponding with the design scheme: during the period from the beginning of the roadbed soil thawing of the highway to the complete degradation of the seasonally frozen layer. To achieve the goal the following tasks were set: to reveal the stress-strain state peculiarities of the road structure and its possible influence during this period on the microdeformations accumulation in the top layer of the roadbed with their subsequent accumulation and copying on the roadway. The author presents the deformation peculiarities results of the pavement during roadbed thawing on the highway A-376 Khabarovsk-Lidoga-Vanino with access to the city of Komsomolsk-on-Amur.