Research on the Deformation and Damage Process of Crushed-Rock Highway Embankment in Permafrost Areas

Since most of the current researches on the crushed-rock interlayer for highway embankment in permafrost region are based on thermal properties, there are few studies on their mechanical deformation characteristics. In order to study the deformation and failure process of crushed-rock interlayer under the long-term settlement deformation of permafrost foundation and to fully consider the discrete characteristics of the crushed-rock interlayer, the finite element model and discrete element model were coupled in this study to accomplish the numerical calculation of long-term settlement deformation of crushed-rock interlayer highway embankment as well as permafrost foundation. The results show that as for the granite blocks adopted in the Gonghe–Yushu expressway, the blocks in the interlayer would be rarely broken, and the deformation of crushed-rock interlayer is mainly caused by the relative movement and rearrangement of the blocks. Based on the calculation results, it is suggested to adopt the uncompacted randomly piled crushed-rock interlayer, which is composed of crushed blocks with more sharp corners. When the size of block varies from 20 to 40 cm, the block size has no obvious effect on the deformation of crushed-rock interlayer, and therefore, the block size could be determined only by the cooling effect of crushed-rock interlayer. At the meantime, the structure layer above the crushed-rock interlayer should also be rigid enough to ensure a smaller uneven settlement value for the superstructure.