Numerical simulation of the subgrade settlement of highway expansion based on CPTU data

ABSTRACT The differential settlement law of new and old subgrade is considered the key problem for settlement control of subgrade in highway expansion in soft soil areas. Along these lines, based on the on-site CPTU test and laboratory test results of the Huai’an-Jiangdu section of the Beijing-Shanghai high-speed expansion project, the physical and mechanical parameters of the soils were obtained in this work. In addition, by performing numerical simulations, the laws of settlement and deformation of both new and old embankments were systematically studied. From the acquired results, it was demonstrated that the deformation regularity of the whole subgrade before and after the expansion was the same, while it was observed that it only diffused outwards. However, according to the analysis of additional deformation after expansion, it was found that the load exerted on the widened part had a greater influence on the widened part of the foundation. The numerical simulation outcomes of the highway expansion foundation can provide design guidance for differential settlement control and monitoring of both the new and old highway foundation.