Search results for "interface shear strength"

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Il calcestruzzo poroso per il miglioramento delle condizioni di stabilità dei pendii sede di falda idrica

2022

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…

interface shear strengthPervious concreteSettore ICAR/07 - Geotecnicashear keys effect.
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La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde

2022

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…

interface shear strengthPervious concreteSettore ICAR/07 - Geotecnicashear keys effect. Pervious concrete for deep trench drains used to stabilise slopes must simultaneously satisfy many requirements namely adequate hydraulic conductiv-ity adequate shear strength a few days after pour-ing capacity to act as a protective filter for soils in which the drain is installed good resistance to clog-ging and adequate residual hydraulic conductivity. The pervious concrete with appropriated mix-design can effectively satisfy all the abovementioned requirements. If the trenches depth is such that they intersect the sliding surface and if the trenches are adequate-ly "socket" in the layers of stable soil there is a fur-ther increase in shear strength due to the shear keys effect. This latter is in addition to the increase in shear strength resulting from the reduction of inter-stitial pressures that remains the principal scope of the draining trenches. Obviously the increase of shear strength due to the shear keys effect occurs if the trenches are filled with material that have enough strength and stiffness such as the porous concrete. In this case the beneficial effects of the draining trenches on stability are also due to the resistance at the concrete interface of the trench - soils and to the intrinsic resistance of the concrete at the area of the trench intersected by the sliding surface taken into consideration.The increase in resistance due to the shear keys effect can be very significant in relation to the thickness and interspace of the trenches. Results reported in the paper demonstrated that the interface fine grained soil-pervious concrete is higher than the residual shear strength of the soil.
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