科研之友
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摘要
Numerical simulations have been extensively used in braced excavation design. However, previous analyses indicate that the universally adopted constitutive models such as Mohr-Coulomb (M-C) model and Drucker-Prager (D-P) model need to be further clarified due to the unsatisfactory prediction of the ground deformation. This study focuses on the features that future continuum models should capture for braced excavation in granular ground. For this purpose, a simplified braced excavation in granular ground was simulated using the distinct element method (DEM). The same excavation case was also simulated by the Finite Difference Method (FDM) using M-C and D-P model to check their applicability. The excavation was 7.5 m in depth and was braced at the level of . The results indicate that the DEM simulation can reproduce the main responses of granular ground during excavation; the excavation initiates failure at the excavation depth of 5.0 m and evolves into total failure at the depth of 7.5 m; two types of stress paths in front of and behind the wall are observed, respectively; obvious principal stress rotations of soils are recognized. Compared with DEM results, M-C and D-P model can generally predict excavation responses qualitatively but under-estimate the ground deformation and internal forces of the wall. This is due to the incapability of the two continuum models to capture the mechanical behavior of granular material under complicated stress conditions in braced excavation. Based on these observations and comparisons, three features are emphasized for future continuum models: stress path dependency, non-coaxiality, and shear dilatancy.
- 出版日期2013-4
- 单位同济大学
