New Structure for Strengthening Soil Embankments

Abstract

A new prestressed reinforcement device (PRD) consisting of two lateral pressure plates (LPPs) and a reinforcement bar is developed to strengthen soil embankments by improving the soil confining pressure and providing lateral constraint on embankment slopes. The reinforcement effects of PRDs were demonstrated by investigating the beneficial effects of increasing confining pressure on the soil behavior via the performance of a series of large-scale static and cyclic triaxial tests on a coarse-grained embankment soil. The results show that PRDs can effectively improve the soil shear strength, bearing capacity, ability to resist elastic and plastic deformation, critical dynamic stress, and dynamic shear modulus, and empirical methods were also developed to determine the critical dynamic stress and initial dynamic shear modulus of the embankment soil. Moreover, 3D finite element analyses (FEAs) with an LPP width of 1.2 m were performed to analyze the additional stress field in a prestressed heavy-haul railway embankment. The FEAs showed that the additional stress at a given external distance from the border of an LPP first increased to a maximum value and then gradually decreased with increasing depth; the additional stress was transferred to the zones where the subgrade tends to have higher stresses with peak stress diffusion angles of 34° (slope direction) and 27° (longitudinal direction); and a continuous effective reinforcement zone with a minimum additional stress coefficient of approximately 0.2 was likely to form at the diffusion surface of the train loads, provided that the net spacing of the LPPs was 0.7 m. The reinforcement zone above the diffusion surface of the train loads can act as a protective layer for the zones that tend to have higher stresses. Finally, the advantages and application prospects of PRDs are discussed in detail. The newly developed PRDs may provide a cost-effective alternative for strengthening soil embankments.