University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Xuetao Wang
(2009):
An updated hypoplastic model, its implementation and ist application in tunnelling.
Doctoral Thesis,
BOKU-Universität für Bodenkultur,
pp 85.
UB BOKU
obvsg
FullText
- Abstract:
- A new version of hypoplastic constitutive model is presented based on a specific constitutive equation by Wu and Bauer (1994). The failure surface and flow rule of the updated model is discussed and the calibration procedure of parameters is provided. The updated hypoplastic constitutive equation is implemented in the finite difference program FLAC3D. The implementation of hypoplastic constitutive model is verified by simulating some element tests e.g. isotropic test, triaxial test, biaxial test and simple shear test. Moreover, the excavation of a shallow tunnel with circular cross section in investigated. The influence of some model parameters on the surface settlement is studied. Then, the model performance is verified against a benchmark problem of a shallow tunnel from FLAC3D handbook. The numerical results are compared with those with the Mohr-Coulomb model. The longitudinal settlement agrees well with those of Mohr-Coulomb model, while the transverse settlement troughs predicted by hypoplastic model are wider than those predicted by the Mohr-Coulomb model. Finally, the hypoplastic model is used for the numerical analyses of the Lainzer tunnel in Vienna, which is being currently constructed according the New Austrian Tunneling Method (NATM). Besides the conventional support measures, advancing face support by horizontal glass fibre anchors is used. The influence of anchors on surface settlement is studied. The numerical results using the hypoplastic model are compared with the instrumentation data from site.