Adjusting temperature distribution under the south and north slopes of embankment in permafrost regions by the ripped-rock revetment

摘要

In this paper, the finite-element formula of convective heat transfer in porous media is obtained by using the Galerkin's method according to the continuity, momentum and energy equations of fluid heat convection for solving the computational problem of temperature field on the ripped-rock revetment embankment in Qing-Tibetan railway. The temperature changes of the ripped-rock revetment and common ballast embankments with south and north slopes have been investigated in coming 24 years, respectively. The results indicate that the ripped-rock of 10 cm diameter is paved on the south and north side slopes of common embankment ballast with the corresponding thickness of 1.6 and 0.8 m, respectively, when the temperature difference of the south and north slopes is 1.8℃, which is able to make the temperature field distribution symmetrical during summertime, permafrost table greatly raised above the native ground surface with frost-susceptible sub-clay (the active layer before embankment construction) completely frozen under embankment during the time, and eliminate the disasters of longitudinal cracks resulting from the uneven settlement of embankment. Thus, we strongly suggest that the ripped-rock revetment embankment be adopted as a kind of embankment structure of Qing-Tibetan railway with south and north slopes in permafrost regions in order to protect the railway as much as possible.