Analysis on the Post-construction Settlement and Influencing Factors for Preloaded Soft Subgrade Based on Parameter Inversion

Aiming at the problem that along a special passenger railway line, the soft soil foundation is widely distributed and the thickness is generally quite deep, leading to diverse foundation reinforcement methods, and in order to ensure required stability and post-construction settlement of soft subgrade, field tests of surcharge pre-loading were carried out in concurrence with field observations. The generalized Kelvin rheological model was employed for foundation parameter inversion and numerical simulation on track-laying construction as well as post-construction settlement prediction were also performed. Results of numerical inversion showed that the foundation parameters were reasonable and reliable and the post-construction settlement was significantly reduced after three months of pre-loading. Several influential factors related to post-construction settlement are highlighted including standing time after roadbed completion, pre-loading height and pre-loading time. It shows that the longer the standing time, the smaller the settlement, and an increase in pre-loading height and time may accelerate the foundation consolidation, thus reducing post-construction settlement.