Analytical and Numerical Study on the Stability of Highway Subgrade with Embedded Loading Berm in Soft Soil Area

Loading berm is an effective method for improving highway subgrade stability in soft soil areas. However, this method requires lots of construction space. It is not applicable in some areas with narrow construction spaces. To address this problem, an embedded loading berm (ELB) is proposed to improve highway subgrade stability, and the effects of ELB on the stability of the highway subgrade were investigated by analytical and numerical methods. Firstly, an analytical model was proposed to analyze the relationship between the ELB dimensions and subgrade stability factors. Then, numerical simulations were carried out to further reveal the stability factor of an actual subgrade with different ELBs. Lastly, ELB parameters’ sensitivity to the ELB stability factors was studied. The results show that the stability of the highway subgrade in soft soil areas can be significantly improved by the proposed ELB. With the loading berm width and height increasing, the subgrade stability factors can increase. The stability factors’ increase ratio with the increased ELB width is greater than that with the increased ELB height. The ELB parameter sensitivity order on the subgrade stability is as follows: width > height > density > cohesion > internal friction. In the design process, the ELB width and height can be mainly focused on. The research is significant for promoting the application of ELB in soft soil areas.