Modeling Differential Settlement in the Partial-Cut and Partial-Fill Embankments of the Mountainous Expressways of China

To simulate the field conditions of a partial-cut and partial-fill embankment, the 3D non-linear finite difference model (FLAC3D) was utilized in this study. FLAC3D is able to visualize and characterize the deformation characteristics and stress distributions. The material parameters were determined from the laboratory tests and knowledge of the site conditions. The analysis results demonstrated that one of the main contributing factors for the settlement is the backfilling thickness as the settlement tended to increase with the backfilling thickness. Also, the maximum differential settlements existed in a small region (about 1.5 meter wide) at the junction of partial-cut and partial-fill embankment. Field evaluations on many expressways have also confirmed that surface cracks often occur in this small region. Transportation authorities can benefit from this study by formulating initiatives to develop cost effective design and construction methods that minimizes cracking, with a focus on the ∼1.5 meter wide region.