Método dos elementos finitos aplicado ao problema de escavação

Abstract

Analysis of a bi-dimensional excavation using the Finite Element Method. The soil is considered to be isotropic and non-linear material, although following Hooke's law for small increments of stresses. The mechanical parameters of the soil are function of the state of stresses. A finite element program was developped which can simulate the several phases of an excavation using the linear strain quadrilateral element, the bar element and the beam element. By using this program the stresses and the strains in the soil as well as in the supporting structures can be computed during: 1. loading dueto surcharges, 2. excavation of diaphragm wall trench with bentonite, 3. concreting of the wall, 4. lowering of the water table, 5. excavation in several steps, 6. preloading of the struts, 7. influence of the temperature on the struts 8. construction of galeries, 9. backfilling. Three applications of the program are presented: a) parametric study of the influence of the temperature on strut loads; b) determination of settlements of buildings during the excavation of a diaphragm wall trench adjacent to these buildings; and e) determination of stresses and strains in soil masses and in the diaphragm wall, bending moments in the diaphragm wall and loads in struts during a three step excavation.