Abstract:Relying on the Shuozhou South Ring Road Reconstruction and Expansion Project, the field experimental analysis method is used to study the law of differential settlement deformation of the municipal road reconstruction and expansion subgrade in the collapsible loess stratum. The result shows that before the whole subgrade soil filling is completed, the most important part is the foundation compression deformation. The foundation settlement still increases after the completion of subgrade soil filling, but the velocity slows down and it is mainly the subgrade consolidation settlement, which can provide a scientific basis for the selection of design and construction schemes of the reconstruction and expansion projects.