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Title: A semi-analytical approach utilising limit analysis for slope stability assessment and optimal design
Author: Wu, Weigao
ISNI:       0000 0004 5992 3846
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2016
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An analytical upper bound method of limit analysis is adopted to derive generalized formulations for assessing the stability of slopes made of geomaterials obeying both the linear Mohr-Coulomb failure criterion and the non-linear Hoek-Brown failure criterion. The thesis is aimed at seeking slope profiles of optimal stability and facilitating the optimal design of pile reinforcement. The ef-fect of the presence of cracks, water pressure, seismic actions, non-homogeneous anisotropic ground and blast-induced damage is investigated. An extensive parametrical study was carried out. A large number of stability and design charts were provided for the benefit of practitioners. A software package to evaluate the safety of slope was created to overcome the limitations of chart-based design using analytical methods. The main findings of this study can be summarized as fol-lows. Firstly, to avoid potential local failure (sliding of the soil/rock mass behind cracks), the most critical failure mechanism should be determined under the constraint of maximum stable crack depth. Secondly, the application of the tangential technique to tackle the non linear Hoek-Brown failure criterion is an acceptable and convenient tool compared with the equivalent C – Ø method and the variational approach. The minimization of the least upper bound solution corresponding to the Hoek-Brown failure criterion has to be implemented under certain stress constraints to avoid any unrealistic selection of tangent lines. Thirdly, contrary to the previous literature assuming en-tirely concave shapes, the optimal profiles exhibit both a concave and a convex part. In comparison with the traditional planar profiles, the percentage of increase in the stability factor can reach (up to) 49%. In addition, for engineered slope excavation, given the same stability factor, the average slope inclination of an optimal slope is always higher than that of a planar slope. The amount of ground excavated for the optimal profile can be as little as 50% of that for a planar profile. Lastly, above-pile failure mechanisms must be taken into account when determining the optimal pile posi-tion otherwise the installation of piles may be completely ineffective.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QE Geology