Hossein A. Taiebat

Simplified Mapping Rule for Bounding Surface Simulation of Complex Loading Paths in Granular Materials

AbstractThis paper presents a bounding surface plasticity model that can be used to simulate complex monotonic and cyclic loading paths. A new mapping rule that only uses the last stress reversal point is introduced to describe the stress-strain behavior of granular soils during loading and unloading. This mapping rule is easy to implement and is suitable for highly erratic cyclic loading conditions, e.g., those induced by earthquake or traffic loading. The application and performance of the model are demonstrated using the results of experimental tests with various stress paths conducted under both monotonic and cyclic loading conditions. The study shows the efficiency of the new mapping rule in capturing the characteristic features of the behavior of granular soils under various loading paths.

H-Adaptive Updated Lagrangian Approach for Large-Deformation Analysis of Slope Failure

AbstractThis paper presents a novel approach to improving our understanding of complicated slope failure mechanisms that can occur in strain-softening material as well as to evaluating the accompanying postfailure deformation of slopes. Three cutting-edge technologies were integrated into one numerical analysis tool: (1) a large-deformation analysis using the updated Lagrangian formulation, (2) a stable numerical algorithm for the solution of progressive failure in strain-softening materials, and (3) an h-adaptive mesh refinement algorithm. The significance of this study is mainly in the adoption of a proper numerical discretization for cases of slope failure in which large deformations lead to distortion of the finite-element mesh, unreliable results, and lack of convergence. The h-adaptive remeshing technique is used to refine the finite-element mesh around the area of large shear strain, thereby improving the accuracy and convergence of numerical solutions. This study presents a method that can be used...

Seismic deformation analysis of a rockfill dam with a bituminous concrete core

This paper reports the results of seismic deformation analyses of Shur River Dam, which is an 84 m high water retaining rockfill embankment with a bituminous concrete core. The proposed Shur River Dam is located in a region of high seismicity in Kerman province, Iran. The purpose of the dam is to store raw and process water for use in the Sarcheshmeh Copper Production Complex. The maximum crest settlement of the dam under three earthquake loadings was evaluated using simplified procedures and numerical analysis. Plane strain, dynamic deformation analysis of the Shur Dam has been performed using the commercial software FLAC and its built-in Mohr-Coulomb elastic-plastic model. The main objective of these analyses has been to identify the earthquake induced movements that could lead to uncontrolled release of water. The predicted deformations are compared with the results of simplified analyses and the observed displacements in other embankment dams [1] during past earthquakes. The relative movement of the asphaltic core with respect to the rockfill material on either side of the core was also studied.