Subsurface settlements of shield tunneling predicted by 2D and 3D constitutive models considering non-coaxiality and soil anisotropy: a case study

Appropriate constitutive models and reliable excavation support sequences are believed to be the major concern in using finite element (FE) analysis simulate shield tunnel excavation. This paper presents systematic two-dimensional (2D) three-dimensional (3D) FE analyses employing a number of accounting for initial soil anisotropy non-coaxial plasticity, as evidenced within site investigations from Tsinghuayuan Tunnel Jing-Zhang high-speed railway China. The aim is assess effects both non-coaxiality on longitudinal transverse tunneling-induced surface settlements. It shown that procedures combined with degree cross-anisotropy key towards accurate prediction maximum vertical displacements tunneling, matching field data. Knowledge strength can further improve shape settlement troughs. When considering n = 0.6 ? 0° simulations, trough obtained almost coincident monitored Initial stiffness used tunnel-induced settlements sandy pebble soils does realism results significantly. predicted by larger than its isotropic counterpart.