Abstract |
The Project aims at developing a new generation of advanced methods for geotechnical analysis characterized by a representation of soils and rocks by
means of material points (the Material Point Method MPM- ) or by means of individual particles (the Distinct Element Method DEM-). The MPM allows
the estimation of safety against failure, just as in finite element methods, but it is also capable of simulating large displacements, accelerations and
velocities. These are aspects directly associated with the evaluation of risk.
The first method concentrates more attention because of its generality ant its potential applications which extend to other fields not directly mentioned in
this document. It is stressed that part of the envisaged work will be made within the umbrella of a Consortium integrated by the University of Delft and
Cambridge University. The objective is to facilitate the access to new applications and common developments.
The Project is divided in three main areas: MPM, DEM and Validation of the models to be developed. In the MPM area, a key development is the
formulation of the method for two-phase materials (saturated soils) and three-phase materials (partially saturated soils). The main objective is to address
the transition stage from static to dynamic conditions of landslides and also its subsequent propagation. The following specific objectives have been
identified: progressive failure, strain rate effects, thermal interactions and developments in numerical techniques.
Regarding the DEM part, the objective is to develop models closer to real materials than most of the available DEM models. In particular one of the aims
is to simulate realistic particle geometries and to implement of particle breakage criteria based on Fracture Mechanics. In this way, significant
phenomena for some applications such as delayed deformations, environmental effects (Relative Humidity) and scale effects (particle size) could be
included in a natural manner.
The Validation stage will cover three aspects: a) The comparison of FE analysis (using the in-house Code_Bright Program) and MPM analysis for a
given problem not involving large deformations; b) The development of a laboratory scaled model for the failure of a slope and its subsequent recording
of deformations and geometric changes using image analysis and c) The performance of suction controlled tests on coarse granular aggregates (which
break at moderate stresses), its recording in real time and its interpretation through image analysis techniques. Model predictions will then be compared
with actual measurements. |