0000000000351437
AUTHOR
Ziccarelli Maurizio
Aspetti geotecnici e marittimi di due interventi di difesa costiera
Two case-histories of the design of submerged breakwaters for coast protection are shortly reported in the paper. The first one refers to the stabilisation and protection works of the sand beach of S.Alessio Siculo village, in Sicily, that suffered severe erosion triggered, some forty years ago, by the construction along the shoreline of a vertical seawall in lieu of the pre-existing sand-dune system. As a consequence, long stretches of the seawall were undermined and collapsed, and the beach almost disappeared. A submerged breakwater was built to reduce the inten-sity of wave attack, the seawall was rebuilt where necessary and provided with a rock revetment at the toe, and then a “perched”…
An experimental investigation into the permeability and filter properties of pervious concrete for deep draining trenches
The reduction of pore water pressures is one of the most effective measures that can be taken to stabilise landslides or to improve the stability conditions of marginally stable water-bearing slopes. To this end, draining trenches have been used long since. When deep trenches are needed, the usual conventional construction techniques fail and recourse must be made to secant piles or to adjacent vertical panels built by means of the methods well established for diaphragm walls. However, unbonded materials cannot be used, since the excavation of a panel adjacent to previously built ones will instabilise these latter. The problem can be solved using pervious concrete rather unbonded material. …
Il calcestruzzo poroso per il miglioramento delle condizioni di stabilità dei pendii sede di falda idrica
Reduction of pore water pressures is a useful strate-gy to improve the stability conditions of slopes. Deep draining trenches can be used for this scope. For the realisation of deep trenches, the usual con-ventional construction techniques are not adequate and the use of adjacent vertical panels, built by means of the methods well established for dia-phragm walls, is necessary. However, unbonded ma-terials (i.e. gravels) cannot be used, since the excava-tion of a panel adjacent to already built ones will cause instability. For this scope a bonded material such as the pervious concrete can be used. It must have high permeability, filtering capacity in order to prevent the internal erosion of…
La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde
Le trincee drenanti profonde rappresentano uno dei metodi più efficaci per la mitigazione del rischio da frana, in pendii con falda idrica. Esse sono realizzate mediante pannelli o pali secanti. Il riempimento è costituito di calcestruzzo poroso o materiale granulare. Se le trincee sono adeguatamente “innestate” nel terreno stabile e il materiale di riempimento ha sufficiente resistenza e rigidezza come il calcestruzzo poroso, si ha ulteriore in-cremento di resistenza a taglio per effetto shear keys, oltre a quello derivante dalla riduzione delle pressioni in-terstiziali. L’incremento di resistenza è dovuto sia alla resistenza all’interfaccia calcestruzzo–terreni sia a quella intrinseca del…