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ef icient projects, with appropriate solutions to the various cycles of life, including the provision for recycling and disposal of materials at the end of the useful life of the building. One of the problems concerning the management of civil construction waste is that segregation of materials by class, aiming at their subsequent recycling or disposal, only happens in the city of Rio de Janeiro within large projects with installed construction sites, although more than half of the produced amount of waste comes from small works which discard their waste into street dump-carts or simply thrown it away on public roads or wastelands. A circular management plan is herein suggested, especially geared for small waste generators, including mandatory segregation of all materials, installation of public collection points through the city neighborhoods and implementation of treatment centers of construction waste, operated by associations of waste collectors, aiming the production of recycled materials. The success of this proposal depends on the effective participation of all agents involved in the process, as the government, owners, companies and other professionals in the construction industry.

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SUMMARYDynamic response of deeply embedded structures, such as underground tunnels and deep foundations, in a multilayered elastic half-space are analysed when the structure is excited by a plane P or SV wave propagating at some angle. The scattered field is represented by the sum of three Green's functions, corresponding to two oscillating forces and one oscillating moment at the centroid position of the buried structure. The amplitudes of these two forces and one moment are a priori unknown and are obtained by satisfying displacement and stress continuity conditions across the nearfield/far-field boundary. The distinguishing feature of this technique from direct or indirect boundary integral techniques is that in these techniques a distribution of sources of unknown amplitude are considered a t the near-field/far-field boundary, and a large number of sources are needed for different combinations of source-receiver arrangements. But in this technique the sources of unknown amplitude are placed at the location of the structure, not at the near-field/far-field boundary and, using the Saint Venant's principle, the scattered field is modelled. Thus, the number of sources required is reduced to only three. Two example problems are solved. The first one is for a deeply embedded footing in a three-layer soil mass and the second one is for a rectangular tunnel in a two-layer soil mass.