CRITICAL-LOOK ON NEW APPROACH FOR GEOMETRICALLY EVOLVING DOMAINS IN GEOMECHANICS

Numerical modelling of geometrically evolving domains, such as multist ep construction, accretion and excavation, has always been of great in terest to geotechnical engineers. Stress, strain and pore-pressure cha nges depend on hydromechanical properties and the loading process. Sev eral techniques are proposed in the literature for numerical simulatio n of excavation or backfilling processes. These are mostly based on a natural methodology that consists in dividing the problem into several time steps, each coinciding with the addition or removal of one layer which is then modelled by means of several elements. Unfortunately, a s in these methods the evolving parameters and their relative influenc e are not explicit, it is not possible to determine their accuracy. A more rigorous approach lies in the geometrical transformation of the s tudied domain, depending on the time variable for a reference domain i n which the conservation equations are verified. The application of th is methodology implies a great number of calculations. By using limite d development techniques of the Jacobian of transformations it is poss ible to reduce the volume of computations. Such a technique results in approximations which can be evaluated.