Lateral deformation of high-speed railway foundation induced by adjacent embankment construction in soft soils: Numerical and field study

Abstract

The excessive displacement of an existing high-speed railway foundation due to the adjacent construction of a railway composite foundation significantly threatens the railway operation safety. In the typical soft soil region of Southeast China, a series of in-situ tests are carried out in this paper to investigate the layered settlement of newly constructed embankment and lateral displacement of an existing high-speed railway foundation induced by the new embankment. A two-dimensional (2D) finite element (FE) model is built to investigate the displacement of stratums and the modified Cam-clay (MCC) model is adopted to pursue the mechanical properties of the silt. Combining the genetic algorithm (GA), a back analysis framework was developed to determine the optimized input parameters of MCC model for silt layer. The results indicate that the displacement of the existing high-speed railway foundation induced by the adjacent construction of a railway embankment decreases with depth and horizontal distance from the newly constructed embankment toe. A hysteresis phenomenon is found in the foundation settlement data during the loading procedure of the embankment. Moreover, the optimized parameters for silt layer (i.e., λ = 0.361, M = 0.828, e0 = 1.347 and k = 0.826 × 10-8m/s) have the potential for the engineer application in the soft soil region.