Thermo-mechanical stability analysis of cooling embankment with crushed-rock interlayer on a sloping ground in permafrost regions

Abstract

Some embankments of highways are inevitably built on slopes in permafrost regions. It is usually difficult to ensure the stability of the embankments on sloping ground because of the asymmetric geotemperature and stress distribution. The crushed-rock layer is often layed in the slope areas to control the geotemperature. Cooling performance is focused to evaluate the thermal stability of crushed-rock embankment, but the mechanics are poorly concerned. This study developed a thermo-mechanical model to evaluate the influence of the cooling effect of crushed-rock layer on the mechanical state of embankment on sloping ground. Two embankments are taken as examples according to the engineering practice in permafrost regions on the Qinghai-Tibet Plateau, i.e., the unprotected embankment and the crushed-rock interlayer embankment. To analyze the stability of sloping embankments, the geotemperature, principal strain, deformation and safety factor in four typical seasons are simulated during operations. Numerical results indicate that the crushed-rock interlayer can effectively cool the sloping embankment and its foundation. Meanwhile, the cooling effect of the porous layer can reduce the uneven settlements to improve the safety reverse of the embankment. This study can also provide scientific basis and reference for the design of similar engineering structures in permafrost regions.