A review of techniques, advances and outstanding issues in numerical modelling for rock mechanics and rock engineering

Numerical methods in rock mechanics

Discrete element simulations of dense packings and heaps made of spherical and non-spherical particles

Formulation of discontinuous deformation analysis (DDA) — an implicit discrete element model for block systems

Concrete gravity dams are an important part of the nation's infrastructure. Many dams have been in service for decades. During the service life of a dam, operating conditions and natural environmental factors may have led to some deterioration in its structural integrity, mechanical equipment, and foundation. Moreover, advances in the methodologies by which design-basis events for natural phenomena hazards are identified have caused these events to be revised upward, in some cases significantly. An increasing number of existing dams fail to meet the more recent performance criteria. A fragility model of a dam provides a tool for rational safety assessment and decision making by using a probabilistic framework to manage the various sources of uncertainty that affect dam performance. In this paper, basic fragility concepts are presented, and databases required to support the fragility assessment are identified. The method is illustrated using a concrete monolith from the Bluestone Dam in West Virginia, designed in the late 1930s. Traditional design practices have been sufficiently conservative that the probability of dam failure under a probable maximum flood 11 m (36 ft) higher than the original design-basis flood remains small.

Fragility analysis of concrete gravity dams

A numerical technique is described for the analysis of multiple interacting deformable bodies undergoing large displacements and rotations. Each body is considered an individual discrete unit, which is idealized by a finite element model. Discrete finite element models interact with their surroundings through contact stresses, which are continually updated as the elements move and deform. The method of analysis consists of a finite element formulation based on a generalized explicit updated Lagrangian method. This formulation is a general finite element formulation, that permits the large deformation analysis of both continuum and discontinuum systems. Different validations of the proposed method of analysis, including cases that involve very large rotations, as well as some examples that demonstrate the application of the discrete finite element method to problems in rock mechanics are presented and discussed in the paper.

J. Ghaboussi

Papers

Discrete finite element method